Water conservancy EPC enterprises have accumulated rich management and experience knowledge in the whole life cycle of the project. In order to solve the problem that enterprise management knowledge has trouble updating and growing, a knowledge fusion method of water conservancy EPC enterprise management based on GNN is proposed. Firstly, the knowledge architecture of water conservancy project management and EPC enterprise management is analyzed, and the data layer of knowledge graph is constructed according to relevant standard specifications and process documents to form the thematic knowledge graph of each module. Then, the knowledge graph of each topic ontology is mapped by instance named entity recognition technology. Then, the graph neural network is used to align the entities to ensure the integration of thematic knowledge. Finally, the Yangtze River protection project is taken as an example to verify the case, and the integration of thematic knowledge map is completed in combination with each stage of EPC project management. The result show that the named entity recognition uses a model based on RoBERTa-wwm-ext, and achieves an F1 value of 0.895, showing good result. In terms of entity alignment, using the AttrGNN method, its Hits@1 and MRR values reached 97.6 and 0.97, respectively, showing a significant improvement. This study provides new ideas and method for improving the management efficiency of water conservancy EPC enterprises and promoting the improvement of management level, which has important theoretical and practical significance.

Municipal pipeline engineering is a key area in urban construction. Traditional method of recording expert construction guidance are inefficient. Speech recognition technology can improve efficiency but often has low accuracy in specialized domains. A speech recognition model was proposed for the pipeline engineering domain based on transfer learning and knowledge distillation. The model uses an end-to-end approach, adapts parameters from an open-domain model to the target domain via transfer learning, and then compresses the model using knowledge distillation.[Results]show that transfer learning reduces the word error rate by 6.2%, and knowledge distillation reduces model parameters by 83.2 MB while improving inference speed.

With the increasing complexity of modern construction projects, safety risks in high-altitude operations and other special construction scenarios have become more prominent, where frequent accidents not only severely threaten workers' lives but also significantly impact construction progress and project quality. To address these safety challenges in complex environments, a safety helmet detection dataset was developed using construction site images that captures workers' wearing characteristics under various conditions, and proposed an improved YOLOv5-based detection model that specifically targets both workers and helmets while enhancing small-object detection capability for high-altitude scenarios. Through network training and performance evaluation, the model achieved 89.8% detection accuracy, demonstrating its effectiveness in enabling automated, comprehensive monitoring that significantly improves inspection efficiency while reducing safety risks and costs associated with manual high-altitude supervision. Experimental result confirm the system's strong robustness in operating reliably within complex and dynamic high-risk construction environments, meeting critical safety management requirements for specialized construction operations.

An in-depth review of the current state of dynamic monitoring and deformation prediction technologies was offered for deep foundation pit engineering within the context of urban renewal. Various aspects were explored such as the evolution of monitoring technology, innovations in data processing method, the diversity of prediction models, and the challenges and solutions encountered in practical applications. By consolidating relevant research findings from both domestic and international sources, a theoretical foundation and technical support were provided for the safe execution of deep foundation pit engineering in future urban renewal projects, thereby fostering further advancements in this field's technology.

In the process of engineering construction, the use of directed video sensors for resource sensing helps to understand the site resource situation, so that strategic adjustments can be made in response to emergencies, but when in a multi-obstacle environment, the resource sensing efficiency is low. Aiming at the characteristics of Yichang two-network project with scattered sites and multi-obstacle environment, it is necessary to study the optimization algorithm of directed video sensor network coverage under scattered sites and multi-obstacle environment to improve the ability of key resource sensing in the field. Using the probabilistic sensing model of directed sensors, multi-obstacle node optimization, node reciprocating motion optimization, boundary problem optimization and virtual force optimization, and considering the variability of node positions, we propose the optimization algorithm for the coverage of directed video sensor networks in a decentralized site with multi-obstacle environments. The experimental result show that the algorithm is optimized to improve the network coverage by 12.03%, which is a higher enhancement of network coverage and better applicability to directed video sensors with different parameters.The optimization algorithm is more applicable to different environments as well as different parameters of directed video sensors, which can provide a reference for the deployment of surveillance cameras in the actual Yichang two-network project, and help to improve the coverage of the surveillance network in the site of the Yichang two-network project.

Mega project represents a multifaceted and dynamic process, characterized by diverse and extensive safety data sources. The existing safety risk evaluation method fail to make full use of safety big data, resulting in the lack of comprehensiveness, objectivity and accuracy of the evaluation result. To accurately assess the risk of safety hazard sources in large-scale engineering construction, a risk evaluation method of construction hazard sources based on D-S evidence fusion and LEC method is proposed. Firstly, the source identification of construction safety hazards is achieved by using the keywords of safety hazards and strong association rules, and the hazard source risk estimation index and its quantification method are given. Then, the D-S evidence fusion theory is applied to process the multi-source information derived from experts' risk estimation result. This process yields corresponding values for human exposure and accident severity indices pertaining to the identified hazard sources. Finally, an improved LEC method is employed to establish a risk evaluation model. To demonstrate the effectiveness of this approach, a case study is conducted, focusing on the hazard source of construction safety hazards in an underground main powerhouse project. The result indicated that the method significantly enhances the accuracy and objectivity of hidden danger risk evaluation, providing scientific data support and a foundation for decision-making in the management of safety hazards during mega project construction.

The Yangtze River Protection Project adopts the EPC contracting mode, which is a large-scale project involving multi-stakeholders and a complex environment. The project faces complex synergistic relationships and difficult synergistic control challenges. Therefore, how to utilize the accumulated empirical knowledge to realize efficient and high-quality assisted collaborative control is the focus of attention of all parties. In order to effectively utilize the text knowledge, BERT-BiLSTM text classification model and RoBERTa-BiLSTM-CRF entity recognition model were proposed. Knowledge extraction experiments were designed relying on the Yichang two-network phase II project, and further knowledge extraction was carried out on the textual information of the Yangtze River Great Protection EPC project, and after entity alignment and structured storage, a replicable and scalable structured collaborative strategy library was finally formed. In addition, the entity recognition model is utilized to obtain the key entity information of the interrogative sentence, and the pending strategy set is obtained through matching retrieval. Finally, the strategy sentence fusion method is utilized to realize the semantic fusion of the pending strategy set based on sentence semantic relations, and the synergistic strategy is proposed to provide an important reference for the synergistic control of subsequent projects.

For engineering, procurement and construction(EPC) projects, the precise assessment and effective mitigation of cost overrun risks by managers are crucial for ensuring strict budget adherence and achieving the project's final profitability. However, existing cost risk management systems for EPC projects still suffer from issues such as delayed warnings and limited accuracy. To enhance the prediction and evaluation accuracy of cost overrun risks throughout the entire lifecycle of EPC projects, the advantages of Markov models and grey prediction models was integrated, applying a secondary Markov correction to the residuals of the grey prediction model. A dynamic early warning model for EPC project cost risks based on grey residual Markov prediction is constructed. Using actual case data from an EPC project, the proposed model's high accuracy and effectiveness in predicting cost overrun risks throughout the project lifecycle are validated. The case analysis result demonstrate that, compared to traditional grey prediction models, the grey residual markov prediction model offers significantly more accurate predictions of EPC project cost overruns, with the average residual error reduced from 4.27% to 1.74%. The findings not only enrich the theoretical framework for cost risk management in EPC projects but also provide practical support for managers in effectively assessing cost overrun risks at various stages of the project lifecycle.

Enhancing the automation level of inventory checks for construction materials is of great significance for improving construction efficiency and project quality. An automatic rebar counting method was proposed based on the improved YOLOv5 algorithm using digital image processing technology. The YOLOv5 network structure is improved by adding a small-object detection layer to obtain larger feature maps, while a weighted bidirectional feature pyramid is used to fuse multi-scale feature maps, retaining high-level semantic information. Compared to the original YOLOv5x model, the number of parameters is reduced, and the model's robustness and inference speed are enhanced, enabling better detection of small rebars at the edges or those partially occluded. Additionally, to address the issue of limited rebar datasets and the uneven distribution of large-scale and small-scale samples, data augmentation method such as geometric image enhancement, noise addition, and brightness adjustment are used to expand the dataset. In the experiments, the YOLOv5 model with the integrated small-object detection layer and weighted bidirectional feature pyramid is compared with the original model on a test set reflecting actual working conditions. The experimental result show that the improved model achieves better detection accuracy and inference speed, with an average precision of 97.00%, an improvement of 1.30% over YOLOv5x, and a frame rate of 59.79 frames per second, which is 6.88% improvement over YOLOv5x. Meanwhile, the F1-score reaches 96.00%, indicating that the model meets the practical requirements and is ready for deployment in engineering projects. The research findings provide an intelligent technical approach for rebar counting and management in construction projects.

In view of the multi-dimensional, dynamic and uncertain characteristics of the fatigue risk of micro-tunneling rock-drilling workers, an early-warning method was proposed based on the Fuzzy-Bayesian Network(F-BN) to achieve accurate assessment and real-time early-warning of fatigue risk. By comprehensively considering factors from four aspects: human, physical, environmental, and organizational management, 24 main risk factors are determined. The fuzzy multi-attribute decision-making method is used to integrate expert evaluation data, and in-depth analysis is carried out in combination with Bayesian network reasoning. The research shows that factors such as “unreasonable work organization and arrangement” and “inappropriate temperature, humidity or air pressure” are key causal factors with high posterior probabilities. They are closely related to fatigue risk and occupy a core position. The main transmission links with high intensity include excessive nervousness→psychological abnormality, overload→external manifestation, etc. The proposed method provides a theoretical basis for the occupational safety and health management of pipe-jacking construction.

A method for assessing the postural load of workers in pipe jacking construction was developed based on digital twin technology. Digital twins enable real-time monitoring, analysis, and optimization of physical entities by constructing virtual models corresponding to real-world objects. In pipe jacking construction, the postural load of workers directly impacts work efficiency and safety. To address this, a digital twin-based assessment method was proposed. First, a digital twin model incorporating workers, equipment, and the environment is constructed, and real-time data is collected through sensors to achieve precise mapping of the physical world. Second, the digital twin model is used to monitor and analyze workers' postures in real time, with algorithms processing the data to derive key posture parameters, such as body position and muscle activity levels. Finally, by integrating ergonomic principles, a postural load assessment model is established, providing scientific support for construction management, optimizing workflows, improving efficiency, and safeguarding workers' health. The research findings offer new insights into the application of digital twins in the construction field. Future work will focus on refining the model to enhance assessment accuracy and practicality, driving the intelligent development of the construction industry.

The quality of construction scheme preparation directly impacts construction safety, quality, and efficiency. Traditional construction scheme compilation and review heavily rely on experts, lack standardized templates, and often involve time-consuming and inefficient processes. To address these issues, an ontology-based knowledge base was developed for construction scheme hazards using the Protégé ontology construction tool and the “Seven-Step Method.” We clearly define classes and their hierarchical structures, object properties, data properties, and constraints, and create instances while ensuring consistency with the built-in HermiT reasoner. A hazard rule base is then built using Semantic Web Rule Language(SWRL), with key information extracted from construction scheme documents being reasoned through the Drools inference engine, verifying the rule base's reliability and feasibility. Finally, case studies validate the reasoning function and achieve automatic hazard early warning for construction schemes. This approach significantly improves the efficiency and accuracy of construction scheme reviews, and identifies potential safety and quality risks, reducing the occurrence of accidents.

The climate of low extreme temperatures and long winter time in alpine regions increases the risk of cracking of concrete dams, and the current thermal insulation measures covered with thermal insulating materials are passive insulation, with cumbersome installation and dismantling procedures. Conductive concrete consists of cementitious materials, conductive materials, etc., both good mechanical properties of concrete materials and unique electro-thermal properties, applied to the overwintering layer of concrete dams and other key parts, both to meet the needs of the dam material performance, but also to maintain the temperature stability of the overwintering layer. Therefore, a finite element model of a typical dam section of a crushed concrete dam in the alpine zone was established, and six overwintering insulation schemes were designed based on the U-ΔT model of the energy supply required for the dam body to resist low temperature, and the temperature control simulation of conventional thermal insulation materials and electrically heated conductive concrete was carried out.The result show that the temperature control of conductive concrete with electric heating can maintain the temperature at the upstream measurement point at 18 ℃, the temperature at the downstream measurement point at 23 ℃, and the temperature at the top measurement point at 30 ℃.[Conclusion]According to the temperature field calculation during the construction period of the crushed concrete dam containing conductive concrete wintering layer, it can be found that the conductive concrete wintering layer electrified in winter has a significant effect on the surface temperature field of the dam, and the temperature difference between the inside and outside of the dam is reduced, which is favorable to the temperature control of the dam, and it can provide new research ideas for solving the temperature control and anti-cracking of the concrete dams in high alpine areas.

The construction system of the Yangtze River Protection Project is relatively complex, and its synergistic state is difficult to be evaluated directly through the engineering construction information, and the existing method rely on the subjective evaluation of the participants. Based on the principle of servitude, a random forest-based evaluation method of the project construction synergistic state was proposed through the fast variable inversion of the sequential parameter. Through engineering research and literature analysis, we select two ordinal covariates, namely, the degree of interest satisfaction and the degree of information matching, and seven fast variables, such as the number of construction reworks, to construct the quantitative relationship between the ordinal covariates and the fast variables, and then carry out statistical analysis. Then, the training set and test set are constructed to establish the prediction model of the two ordinal covariates of interest and information, and the model is verified and evaluated by the ten-fold cross-validation method and the test set verification, respectively, and the matching rule between the ordinal covariates and the collaborative state is established as the basis of evaluation. This matching relationship between ordinal parameters and synergistic state matches the predicted values of ordinal parameters with the synergistic state of subsystems, and obtains the synergistic state of the corresponding subsystems, which provides a basis for the evaluation of the synergistic state of engineering construction.

Engineering construction is a typical knowledge-intensive field, where experiential knowledge is an important source of construction knowledge. Effectively acquiring construction experience is one of the key tasks for enterprises. However, such experiential knowledge is characterized by fragmentation and tacitness, making it difficult to collect and utilize. To address this, a method for intelligent guidance of construction experience and key knowledge matching is proposed. First, a prompt-based text classification technique is introduced to locate the content of construction experience knowledge by dividing expert experience texts into different thematic text blocks. Based on this, by analyzing the characteristics of construction experience texts and construction specification clauses, the study proposes a approach—regular expressions to construct rules. These rules are then utilized in matching analysis to align the elements of expert experiential knowledge, ultimately generating prompt information to guide experts toward further reflection and targeted responses. This method offers a new approach for the in-depth excavation and utilization of construction experience in engineering.

In the process of historical construction of water conservancy projects, limited by the level of text informatization, a large number of non-editable documents of hydraulic concrete materials have been accumulated in the form of paper texts and scanned images, making it difficult to directly and effectively utilize material data, greatly increasing the difficulty of applying material knowledge. A document parsing method was proposed based on machine vision and deep learning, which accurately and efficiently converts the text information and table data of hydraulic concrete materials into editable form. Furthermore, based on the interpreted table information, a database of hydraulic concrete material tables was constructed, achieving efficient querying and unified management of concrete material data. Taking the actual engineering hydraulic concrete material document as an example to verify the feasibility of new method, the result show that the accuracy of each subtask of the document parsing method is over 90%, which is helpful for the automated reuse of non-editable resources of concrete materials and improves the data service capability in the field of water conservancy engineering.

With the commissioning of cascade reservoirs in the lower reaches of the Jinsha River, sediment discharge at Xiangjiaba Station has decreased substantially, leading to corresponding sediment reduction in inflows to the Three Gorges Reservoir(TGR). To investigate the changes in erosion-deposition characteristics in the tail area of TGR under altered water-sediment conditions, hydrological data from main control stations on the Upper Yangtze mainstream, Minjiang and Jialing Rivers was analyzed, along with years of cross-section data from Tongluoxia to Fuling in the TGR tail reach. Comparative analysis of changes in inflow water-sediment into the TGR and siltation changes in the tail area of TGR before and after 2012.The result show that compared to the period from 2003 to 2012, there was no significant change in the runoff at Cuntan station during the period from 2013 to 2024, while the sediment discharge decreased by about 63%. The intra-annual distribution was more concentrated from July to September. The sediment deposition in the river section from Tongluoxia to Fuling decreased by about 56%. The contribution rate of sediment deposition increased during July to August and decreased in November. The result indicate that the decreased sediment inflow into the TGR has significantly alleviated sedimentation in the reservoir tail section. With sediment transport becoming more concentrated during flood seasons, the proportion of July—August deposition contribution to annual sedimentation rose.During flood periods with high sediment-concentration inflows, appropriately reducing peak-flow clipping could further mitigate tail-section sedimentation, provided operational conditions permit.

The Three Gorges Dam's operation has profoundly influenced hydrological conditions in the middle Yangtze River basin. Using data from extreme droughts spanning 2010—2020 and 2022, precipitation, temperature, water level trends, and drought responses was studied through SPI(Seasonal Precipitation Index) analysis and regression method. Key findings include:(1)Precipitation showed marginal increases during 2010—2020 with stable temperatures, while the Lishui River 16.5~17.5 ℃ experienced water level 23.5~26.8 m fluctuations.(2)SPI values ranged between-0.5 to 1.0, indicating normal conditions(55%) and mild drought(30%), with annual patterns showing initial aridity followed by recovery.(3)Water levels demonstrated positive correlations with precipitation and runoff but negative correlations with temperature.(4)June 2022 saw a sudden drop from 27.3 m to 28.3 m, followed by moderate to severe drought from January to June. Notably, April, May, and July water levels showed significant SPI correlation, reflecting summer drought characteristics. The research provides critical insights for agricultural disaster prevention and integrated Three Gorges-lake basin management strategies.

As an important carrier of water resources and water environment, small and micro water bodies play an important role in water storage, drainage, water conservation and water purification, and are closely related to people's production and life.In recent years, the small and micro water bodies in the rural resettlement areas in the Three Gorges Reservoir area have shrunk, the water quality has deteriorated, and the functions are not up to standard, which is one of the environmental problems strongly reflected by the migrants.Based on the principle of water ecological restoration, a variety of restoration combinations was used such as ecological purification beds, wetland plants and artificial aquatic plants to restore the function of water ecosystem and improve the landscape effect. Taking two types of small and micro water bodies of ponds and streams in a resettlement village in Zhuyi Town, Fengjie County, Chongqing as demonstration objects, this study carries out technical demonstration to improve water quality, restore the function of water ecosystem and enhance the landscape effect. The water quality monitoring result showed that after the main external pollution sources were reduced and controlled, the indicators of COD_Mn, NH₃-N, TN, TP and other indicators in the demonstration small and micro water bodies reached above the class Ⅲ water quality standard of the GB3838-2002, and the functions of the water ecosystem were restored. The demonstration effect was good, which provided technical reference and case reference for the comprehensive treatment of small and micro water bodies in the reservoir area.

The smooth implementation of the resettlement work in the reservoir under construction is a fundamental prerequisite to promote the construction of the hub project, through the implementation stage of the resettlement work of immigrants to implement the analysis of the key difficulties, in order to implement the resettlement work of immigrants to form an effective control of the whole process. The JH reservoir project was taken as an example, analyzes the implementation of resettlement work after the approval of the preliminary design report of the project from the perspectives of organization construction, resettlement implementation, resettlement fund management, resettlement acceptance, resettlement petition and rights and interests of the immigrants, etc., and refines the key points of resettlement work, and puts forward the corresponding measures and suggestions according to the local conditions. The result show that: JH Reservoir immigrant resettlement implementation difficulties are mainly reflected in the immigrant resettlement implementation of the preparatory stage, the immigrant resettlement implementation stage, the immigrant resettlement acceptance of the three stages of the 10 aspects, a comprehensive proposed rationalization measures and recommendations for the 10. The result show that: the implementation of resettlement in reservoirs under construction to analyze the difficulties and put forward countermeasures, the outline of the implementation of resettlement to seize the key points and the core of the work of resettlement, similar to large and medium-sized water conservancy projects resettlement work has a good reference significance.

In the construction of the reservoir resettlement work is to promote the smooth implementation of the fundamental prerequisite for the construction of the hub project, through the implementation stage of the resettlement of immigrants to implement the analysis of the difficulties in the implementation of the resettlement of immigrants to the implementation of the whole process of the formation of the resettlement of immigrants to effectively control.The JH Reservoir Project was taken as an example, and makes a comprehensive analysis of the implementation of immigrant resettlement after the approval of the preliminary design report of the project, from the perspectives of the construction of organizations, implementation of immigrant resettlement, management of immigrant funds, acceptance of immigrant resettlement, immigrant petitions and rights and interests of the immigrants, and so on, so as to distill the important points of the immigrant resettlement and to put forward the corresponding measures and suggestions according to the local conditions.The result show that: JH Reservoir resettlement implementation difficulties are mainly reflected in the resettlement implementation of the preparatory stage, resettlement implementation stage, resettlement acceptance of the three stages of the 10 aspects, a comprehensive rationalization measures proposed 10 recommendations. The result show that: analyzing the difficulties and proposing countermeasures for the implementation of resettlement of immigrants in under-construction reservoirs and grasping the key points and core of the resettlement implementation work in the outline are of good reference significance for the resettlement of immigrants in similar large and medium-sized water conservancy projects.

To address the challenges faced in applying whole-process engineering consultancy in post-resettlement support projects for reservoir migrants, Analyzing the key issues that are based on the impending expiration of post-resettlement support policies. These issues include difficulties in preliminary work and implementation management, a shortage of specialized talent, and inadequate asset management. By summarizing practical experiences with whole-process engineering consultancy models in post-resettlement support projects in Jiangxi, Hubei, Guizhou, and Guangxi provinces, a fully digitalized implementation pathway was proposed comprising six stages: database construction, technical module optimization, specialized data collection, talent team building, artificial intelligence development, and customized system construction. Combined with the whole-process consultation system of the reservoir resettlement support project, the specific applications of digital systems in dynamic migrant population management, fund and project management, asset maintenance supervision, socio-economic monitoring, and data management for ongoing reservoir projects. This provides practical references for the precise implementation of post-resettlement support projects and the high-quality development of migrants.

Based on the investigation of the current situation of domestic sewage treatment in rural resettlement areas in the Three Gorges Reservoir area, aiming at the characteristics of large number of villages, scattered settlements and complex terrain in rural resettlement areas, and aiming at water quality purification and collaborative resource utilization, one rural resettlement residential area was selected in Zigui County in the Three Gorges Reservoir area for demonstration, and applied the ecological and unpowered technology of vertical subsurface flow+horizontal subsurface flow hybrid constructed wetland+water quality control and on-demand discharge to treat domestic sewage.The monitoring results showed that the average removal rates of COD_Cr(chemical oxygen demand), BOD₅(biochemical oxygen demand), TN(total nitrogen), TP(total phosphorus) and NH₃-N(ammonia nitrogen) were 79.11%, 84.51%, 43.42%, 59.71% and 71.89%, respectively. This technology has the advantages of good treatment effect, simple operation and maintenance, no power consumption, low construction and operation cost, and is not limited by the treatment scale and terrain. It is suitable for the treatment of domestic sewage in residential areas with a population of 50~200 people in the mountainous area, and provides technical reference and case reference for the ecological treatment and resource utilization of rural domestic sewage in the Three Gorges Reservoir area.

The implementation experience of the water supply upgrade project in the Xiangxi River left bank rural resettlement area of Xingshan County waw summarized. By making comprehensive use of limited water sources in mountainous areas, following the overall policy of primarily centralized water supply with supporting dispersed water supply, optimizing the layout of rural water projects, and applying water affairs information systems, a scientific water management platform can be constructed. This approach enables scientific, digital, and professional management of water affairs, establishes a reasonable water pricing and fee collection mechanism, and continuously improves rural water supply security. It is a fundamental measure to connect the last mile of water supply security network, safeguard the lifeline of rural drinking water in mountainous areas, and achieve high-quality development of rural water supply in mountainous regions. To ensure high-quality development of rural water supply in mountainous areas, suggestions such as strengthening the construction of water affairs intelligent platforms, increasing the adoption rate of smart water meters, and investing in the training of water supply professionals are proposed.

The relocation and resettlement of large and medium-sized reservoir immigrants is a complex socioeconomic reconstruction project, recognized globally as a significant challenge. To assist immigrants in restoring their livelihoods, the state has implemented a series of support measures. Through extensive field research and analysis, it has been observed that the current reservoir immigrant population exhibits a “large-scale dispersion and small-scale agglomeration” pattern, characterized by scarce land resources, limited self-development capabilities, and persistent disparities in development between reservoir areas and immigrant resettlement zones. Additionally, contradictions between ecological conservation and industrial transformation in certain regions remain prominent.In particular, immigrants relocated prior to 1985 face significant difficulties in achieving comprehensive recovery and sustainable development, with their overall living standards lagging behind the goals of common prosperity. To address these challenges, further targeted support measures are urgently needed to consolidate and enhance policy outcomes. Drawing on national strategies for rural revitalization, common prosperity, green low-carbon circular development, and high-quality growth, this paper proposes policy recommendations to promote the transformation and sustainable development of reservoir areas and immigrant resettlement zones. The objective is to ensure that immigrant communities achieve common prosperity in tandem with other residents, aligning with broader societal progress.

To further improve the quality management system of hydrological flood reporting data and achieve real-time anomaly monitoring, this study explores the cross-disciplinary application of deep learning algorithms in hydrology. By analyzing the time-series characteristics of hydrological reporting data, a hybrid model combining Convolutional Neural Networks(CNN) and Long Short-Term Memory(LSTM) networks is proposed to enhance feature extraction and processing. Furthermore, considering the physical process of river flow, spatial correlation features embedded in upstream and downstream water level and flow data are integrated to enable multi-step time-series forecasting. A dataset comprising three years of monitoring data from representative stations across the upper, middle, and lower reaches of the Yangtze River was constructed for simulation. The result demonstrate that the proposed CNN-LSTM model achieves a coefficient of determination(R²) of 0.77 for water level prediction and 0.84 for flow simulation, indicating good performance in hydrological forecasting. Building upon this, an integrated anomaly detection framework based on “prediction-residual-discrimination” is developed. In the case study of the Three Gorges Reservoir, the anomaly detection rate reached 100%, with an R² of 0.991 for water level simulation, effectively enabling the identification of abnormal flood reporting data. This study provides a robust intelligent algorithmic foundation for enhancing the quality of hydrological reporting data in river basins.

In order to effectively solve the problems of water resources shortage in western Chongqing and ensure that its water resources supply capacity matches its strategic position and social and economic development. The current situation of water resources in the region and the new water supply capacity under construction and planned are sorted out. Economic development and water demand are forecasted, and the contradiction between water resources supply and demand are found. A multi-source complementary water resources allocation scheme is proposed based on local water, transit water and regional external water transfer. The idea and path of building a "Zhong-shaped" three-dimensional regional water network in the western Chongqing region, with a view to providing reliable water resources guarantee for the integrated high-quality development of the west Chongqing area and helping the construction and development of the Shuangcheng economic circle in the Chengdu-Chongqing area, ultimately achieving major decision deployment of creating an important growth pole for high-quality development.

The deformation of high-core rockfill dams is one of the most direct and reliable indicators for assessing the operational state and safety conditions of dams. Accurately predicting dam deformation and uncovering its patterns are crucial for adjusting construction plans or improving dam safety management strategies. To address the issues of local optima entrapment and handling large-scale data in dam deformation prediction models, the Enhanced Beluga Whale Optimization(EBWO) algorithm is utilized to optimize the hyperparameters of the Light Gradient Boosting Machine(LightGBM), aiming to obtain the optimal hyperparameter combination. This forms the basis for constructing a deformation prediction model of high-core rockfill dams based on EBWO-LightGBM. Taking a high-core rockfill dam in the Southwest as a case study, EBWO-LightGBM, standard LightGBM, ELM, SVM, and RF models were developed, and their predictions analyzed. The EBWO-LightGBM prediction model achieved a correlation coefficient(R²) of 98.2%, an improvement of 3.81% over standard LightGBM, and a reduction in Root Mean Square Error(RMSE) of 11.72%. This demonstrates that the model effectively balances global and local performance, enhancing predictive capabilities. Compared to ELM, SVM, and RF models, the EBWO-LightGBM model showed an increase in R² by 4.80%, 4.58%, and 4.25% respectively, and a decrease in RMSE by 13.41%, 13.18%, and 12.75%, confirming its superiority.

Based on the back analysis of concrete dam mechanical parameters by using traditional neural network model, the BP neural network model is combined with orthogonal experiment design theory, the back analysis model of concrete dam mechanical parameters is optimized. By building a three-dimensional finite element model, the parameters of concrete and bedrock are calculated based on the arch dam and its deformation monitoring data by the back analysis. The calculation result is close to the design value and has a certain degree of improvement. Finally, the back analysis result are taken as the input of the finite element model, and the reliability of the calculation result is verified by the output result. It is proved that the optimized method improves the efficiency and accuracy of the neural network model.

To study the effect of artificial sand mica content on temperature control and crack prevention of concrete structures, for concrete with different artificial sand mica contents, all temperature control and crack prevention calculation parameters(excluding creep) were experimentally measured, numerical simulation analysis of temperature control and crack prevention for ultra-high arch dams in high-altitude cold regions was carried out. The research result indicate that the mica content has an impact on the maximum stress of the structure at around 0.1 MPa and on the temperature peak at around 0.7 ℃. The content of artificial sand mica ranges from 6.5% to 2.9%, and changes in mica content have a significant impact on the structural safety factor; When the content of artificial sand mica is below 2.9%, the change in mica content has little effect on the structural safety factor. Within the allowable temperature control standards in the design, even for high-altitude and cold areas with ultra-high concrete arch dams, concrete with an artificial sand mica content of 4.5% can meet the recommended safety factor of 2.0 in the specifications The artificial sand mica removal technology can effectively improve the safety factor of concrete arch dams, avoid the harm of mica in artificial sand to the temperature control and crack prevention of arch dams, provide support for ensuring the safety of arch dams and increasing the selection of raw materials, and have great reference value for the construction of subsequent projects.

The combination of winter surface layers and crack prevention is a key and difficult point in the construction of concrete dams in high cold areas. Based on the monitoring data and observation result, through three-dimensional finite element numerical simulation analysis, the influence of different factors on the normal stress of the interface between new and old concrete after overwintering is explored. Through simulation result, the interlayer stress state under different factors such as temperature difference between upper and lower layers, self generated volume deformation, and interlayer bonding strength is elucidated. The analysis result indicate that the opening, closing, and bonding state of the winter layer in high-altitude cold regions depend on three key factors: temperature difference between new and old concrete, self generated volume deformation, and interlayer bonding strength during construction. The temperature difference between new and old concrete and the self generated volume deformation will result in a larger normal stress as the driving force to prevent interlayer bonding, while the interlayer bonding strength will serve as the resistance force to prevent interlayer cracking. According to the analysis result, it can be concluded that the key control indicators for newly poured concrete in high cold areas after overwintering are the temperature difference between new and old concrete, as well as the strengthening of interlayer bonding through special interlayer construction techniques. The interlayer surface stress caused by the difference in self generated volume deformation caused by the temperature difference between upper and lower layers is relatively large, especially under the effect of end constraints. Therefore, increasing interlayer bonding strength while ensuring temperature control measures is also a key construction focus for newly poured concrete after overwintering.

The maximum dam height of the Yecha Reservoir Dam in Fengjie, Chongqing is 90 m. The dam is designed as a concrete face rockfill dam. The material field for the dam is located at the tail end of Jiudongxi Creek, a tributary on the right side of the reservoir. The geological formations in the material field consist of limestone interbedded with breccia, where limestone is classified as hard rock and breccia as soft rock. The zoning and material design of the dam are crucial aspects in designing high concrete face rockfill dams. To optimize the utilization of material resources and reduce the amount of material waste, thereby lowering project costs, finite element stress-strain analysis was employed to study the feasibility and appropriate mixing ratios of hard and soft rock materials in the primary and secondary rockfill zones. The research findings indicate that limestone should be used as the dam material in the primary rockfill zone of the Yecha Reservoir Dam. In the secondary rockfill zone, a mixture of limestone and breccia with a ratio of at least 60% limestone to 40% breccia is recommended. Additionally, excavation material from the weakly weathered sandstone and shale in the core area should be used in the dry upper section of the secondary rockfill zone.

During the initial impoundment period of super-high arch dams, the monitoring data are characterized by dynamic variation and complex environmental influences. Traditional models often suffer from poor prediction stability under data-scarce conditions and insufficient capability to capture nonlinear patterns when data are abundant. Therefore, there is an urgent need to establish a high-adaptability prediction model that integrates physical constraints and data-driven capabilities. This paper proposes an HST-NN integrated model, which combines the physical mechanism constraints of the HST(Hydrostatic-Seasonal-Time) formula model with the nonlinear feature learning ability of a Deep Neural Network(DNN), to accommodate the evolving data conditions throughout the entire impoundment process. The model is constructed and validated in stages based on measured deformation data from the initial impoundment of a 300 m-class super-high arch dam.Results show that the proposed model maintains a relative error within 10% under data-scarce conditions and further reduces to below 5% as data increases. Compared to traditional single models, the HST-NN model significantly improves prediction accuracy and stability. It demonstrates strong adaptability and generalization, providing an effective tool for deformation prediction and safety management during the initial impoundment of super-high arch dams.

The dynamic stability analysis of sluice gates in high seismic intensity areas is an important issue in dam design. Relying on a sluice gate project in a strong earthquake area, a three-dimensional finite element model of the sluice gate-reservoir water-foundation system was established. The model considered the radiation damping effect of infinite foundation, the nonlinearity of foundation rock and soil materials, and the dynamic contact nonlinearity between the sluice gate and the foundation. The finite element time history analysis method was used to conduct a nonlinear seismic response analysis of the sluice gate. The criteria for overall structural instability were the sudden change in overall displacement of the sluice gate, the penetration of the sliding zone at the interface between the sluice gate and the foundation, and the non-convergence of dynamic calculations. The overall stability of the sluice gate under strong earthquakes was evaluated. The result showed that under various seismic conditions, the overall deformation pattern of the sluice gate-foundation system was normal, the deformation values were controllable, the sluice gate did not undergo overall sliding along the interface between the structure and the foundation, and the overall stability of the sluice gate-foundation system could be guaranteed.

In cases where the three major ecological red lines such as basic farmland and nature reserves are restricted, the use of asphalt concrete core walls as anti-seepage measures to replace clay core walls in earth-rock DAMS is a new trend in water conservancy engineering construction and also a new innovative path. Through the static and dynamic test research on dam-building materials, the calculation parameters are provided for the finite element numerical analysis of the mechanical properties of dam-building materials. Three-dimensional finite element static and dynamic calculation, analysis and research on the dam are carried out, and targeted engineering measures are proposed for the engineering characteristics of dam construction materials, the stress and deformation characteristics, stability and seismic safety of the dam, the stability of the dam body under design verification conditions, stress and strain characteristics, dam body structure, parameters and control standards of dam construction materials, deformation characteristics of the dam body, and seismic engineering design.

To address the issues of poor quality and excessive noise in point cloud models of prefabricated bridge components, this study analyzes the underlying causes of these quality problems. Based on the identified sources of noise, a high-frequency noise removal algorithm utilizing the spatial relationships of neighboring points and a low-frequency noise smoothing algorithm based on bilateral filtering are proposed. A 25-meter-long concrete T-beam is used as a case study to verify the effectiveness of the proposed algorithms. Experimental result demonstrate that the proposed method can efficiently eliminate both high-frequency and low-frequency noise, significantly enhancing the quality of the point cloud model. Comparative analysis with existing method further confirms the superior efficiency and effectiveness of the proposed approach.

Curtain grouting in the Xiyu conglomerate region is a critical component of seepage control systems for water conservancy and hydropower projects in Xinjiang. It is also a key focus for construction management and quality control in such projects within this geological context. Based on an analysis of the permeability characteristics of Xiyu conglomerate and conventional quality control method in grouting construction, this study systematically investigates the correlation among grouting flow rate, grouting pressure, and the permeability coefficient of Xiyu conglomerate under specified slurry density conditions. Through quantitative analysis, a quality control model for the grouting process, characterized by parameters Q(flow rate), P(pressure), q(permeability), and t(time), is established. Furthermore, new quality control parameters for grouting are proposed, offering an innovative approach for quality management in water conservancy projects within Xiyu conglomerate regions. The proposed model was validated through grouting experiments conducted at the Momoke Water Control Project, and the experimental result confirm its applicability and effectiveness.

The phenomenon of temperature rise is common in ultra-high arch dams. In order to gain a deeper understanding of the causes and processes of temperature rise, this article takes a certain ultra-high arch dam as an example to analyze temperature monitoring data. Through a combination of simulation calculation and regression analysis, a calculation model for the later temperature rise of the arch dam is constructed to conduct in-depth research on the problem of temperature rise after the arch dam is sealed. Results has shown that:(1) The temperature rise after arch dam sealing is influenced by two factors: the internal transmission of external temperature and the hydration heat of concrete in the dam body. However, the speed of internal transmission of external temperature is slow, and the impact on the temperature rise inside the dam body is relatively small. Moreover, the measured maximum temperature of the dam body is higher than the stable temperature. Therefore, the main reason for the temperature rise after arch dam sealing is the hydration heat generated by concrete;(2) It takes 3~6 years for a certain ultra-high arch dam to reach its maximum temperature, and about 20 years to reach a stable temperature;(3) The hydration heat mainly affects the temperature rise inside the dam body in the early stage after arch sealing, and has no effect on the final stable temperature field of the dam body.

To meet the requirements of water conveyance, pumping stations in the Yangtze River to Huaihe River Project are designed with ultra long and large integral pouring structures, making temperature control and crack prevention much more difficult than other water diversion pump station projects. In order to explore the temperature stress and cracking characteristics during the construction of this seamless pumping station, the feasibility for crack prevention measures with easy operation and reasonable temperature control are demonstrated. Selecting the Zongyang Pumping Station as the research object, based on finite element simulation calculation of pouring process during construction, considering the influence of real environment, materials, structure, and various temperature control measures, the temperature and stress field, crack risk are analyzed. The result show that the ultra long bottom plate, thick side wall and upstream wall of the inlet channel layer are the key points for structure crack prevention; the tensile stress is mostly between 2.0 MPa and 3.0 MPa, exceeding the allowable tensile strength of concrete during construction; By adopting a combination of surface insulation, water cooling and temperature control pouring with differentiated control, the risk of cracking can be greatly reduced. The temperature control and crack prevention measures tailored to local conditions are feasible, which can provide reference for the structure crack prevention design of integral pouring pump stations in other water diversion projects.

The water conveyance project of Beikeng Reservoir adopts pressurized gravity flow for water conveyance throughout the whole process, and the end water receiving point is the central water plant. The design diversion flow is 7.64 m³/s and the tunnel diameter is 2.4 m. The total length of the water conveyance tunnel is 8 757 m. The river terraces and eroded low mountain landforms are along the tunnel. The terrain is undulating. The buried depth of the tunnel is about 50 ~ 390 m, mainly through tuff, slate and shale. The drilling and blasting method, open TBM method and double shield TBM method are compared and selected for 1~# tunnel. From the aspects of avoiding engineering risk, reducing environmental impact and ensuring the implementation progress of the project, the drilling and blasting method is not suitable. From the perspective of controlling engineering investment, the open TBM scheme is selected.

Grouting test is a test carried out before preliminary design or bidding design, which supplements the insufficient amount of exploration works in the early stage and can also improve the investigation accuracy of the project. Various parameters obtained can directly enter the analysis of the project cost and unit price to guide the completion of grouting design, and will not lead to the increase of grouting works and design changes during the construction process. Therefore, the increase of project investment and the extension of construction period are caused. The productive grouting test is the test conducted before the construction of grouting, which is to verify the rationality of the recommended parameters of grouting design. However, the unreasonable parameters of grouting may lead to major design changes, resulting in the increase of project investment and the extension of project duration. Therefore, grouting test is particularly important and necessary for water conservancy projects, especially large and medium-sized water conservancy projects.

Rock burst is one of the main engineering geological hazards during the excavation of hydraulic tunnel. Rock burst propensity prediction is a major problem in rock engineering that must be solved. At present, the evaluation index of rock burst tendency of rock has not formed a unified standard, which makes it difficult to accurately predict and prevent rock burst disaster of hard rock engineering. Based on the laboratory test of rock burst liability, four kinds of rock burst tendency indexes are selected for principal component analysis, the principal components which can be used to explain rock burst tendency are extracted, the weights corresponding to four kinds of rock burst tendency indexes are obtained so that the comprehensive grading of rock burst tendency has been completed. This comprehensive grading method provides a new method and a new idea for the workers of hydraulic tunnel construction site to judge the rock burst grade accurately and timely.

Tunnel construction, as a crucial component of infrastructure development, often encounters complex geological conditions and high-risk construction environments, posing significant challenges to construction safety management. To effectively utilize multi-source data and intelligent technologies for the efficient management of safety and quality in tunnel construction, a multi-data integrated tunnel construction safety information management platform has been developed. This platform aims to address the information management challenges of various types of data in tunnel construction and enhance the controllability of the construction process. Based on BIM, artificial intelligence, and IoT technologies, the platform integrates modules such as personnel management, equipment monitoring, safety warning, and progress management, achieving refined management throughout the entire tunnel construction process. The platform also includes the lining trolley in the scope of digital management and improves the predictive capability and response efficiency of construction management through intelligent data collection and multi-dimensional data analysis. Practical application result demonstrate that the platform effectively enhances the safety and management efficiency of tunnel construction.

Construction system simulation method serve as effective tools for optimizing the analysis of underground cavern group construction processes. To enhance resource utilization and reduce construction costs, “Resource Sharing in Construction” is routinely practiced across various workfaces of underground caverns. However, existing construction simulation studies fail to thoroughly analyze the transfer of construction resources between different workfaces, subsequently affecting the accuracy of the simulation outcomes. Addressing this issue, this study proposes a construction simulation method for underground cavern groups that incorporates resource sharing. The approach starts by analyzing multi-dimensional constraints on resource sharing from temporal, spatial, operational, and organizational perspectives. Further, a tiered construction simulation model is developed, which models resource entities as independent objects to simulate their active and idle states individually. These resource objects are then integrated with the CYCLONE model, enabling precise descriptions of resource flow and detailed simulation of the construction process. Engineering case studies demonstrate that, compared to traditional simulation method, the simulation result incorporating resource sharing provide more accurate predictions of construction timelines and machinery deployment, aligning closely with real-world engineering conditions.

A multifunctional non-dismantling insulation formwork technology for ultra-high arch dams in severe cold regions is proposed to address critical challenges such as the shortage of construction periods, significant cross-interference during construction, and the detachment of permanent insulation layers during operation. By combining structural optimization design, numerical analysis, and model testing, this article proposed the structural design and bearing capacity verification of the formwork under harsh service conditions. The result demonstrate that the final composite multifunctional formwork structure meets the performance requirements under complex external loads, including water load, wind load, temperature load, ice pulling, and ice pressure. The design effectively integrate the functions of insulation, construction formwork, anti-ice-pulling, and anti-seepage. Furthermore, the non-dismantling formwork eliminates the need for removal after built, thereby simplifying the construction process, reducing cross interference during construction, and resolving issues related to both permanent and temporary insulation. This approach provides a comprehensive solution to the durability problems of high arch dam insulation systems during operation under complex cold conditions, meeting the requirements of temperature control and crack prevention.

Aiming at the key technical problem of joint waterstop for prefabricated non-removable formwork of high arch dams, waterstop tests were conducted on two structural forms: waterstop rubber strips and polyurea coating. The influence of different waterstop materials, structural forms and construction techniques on the waterstop performance of the joint of prefabricated concrete components is analyzed. The test result show that when the external water pressure is 1.5 MPa, there is no leakage in the joint with the polyurea coating waterstop structure. When the water pressure is 0.6 MPa, the waterstop structure with rubber strips causes internal water pressure cracking and water leakage at the local coating. Meanwhile, the joint with rubber strips needs to be continuously pressed with 4 MPa to achieve the above waterstop effect. By comparing the waterstop performance, construction convenience and the strictness of requirements for assembly equipment of the two structures, it is recommended to adopt the polyurea coating waterstop structure for the joint waterstop of prefabricated non-removable formwork on the upstream face of high arch dams. This solves the key problem of joint waterstop of prefabricated non-removable formwork of high arch dams, which affects the structural safety and durability, and provides theoretical basis and practical reference for improving the waterstop effect of the joint of prefabricated components.

In order to reduce or avoid the risk of TBM construction in urban hydraulic tunnels, it is necessary to construct a set of comprehensive advanced geological prediction technology for the high-risk characteristics of TBM construction in urban hydraulic tunnels. Under the condition of fully analyzing the characteristics of urban hydraulic tunnels and the risks of TBM construction, the geological analysis method is used to preliminarily determine the main unfavorable geological bodies and geological defect parts(sections) as the key points of prediction, so as to determine the targeted geophysical exploration and drilling detection method and implementation parts(sections). Then, the obtained data and information are comprehensively interpreted in geology, and finally the surrounding rock types and main unfavorable geological bodies in front of the tunnel face are predicted. The possible geological disasters such as surrounding rock collapse, water and mud inrush and soft rock deformation are analyzed, and then the possibility and harm degree of accidents such as TBM equipment jamming, submergence and ground collapse are predicted, and targeted measures and suggestions were put forward. The prediction technology has been applied to several major urban hydraulic tunnel projects. According to the analysis of the applied engineering effect, the accuracy of the prediction of the surrounding rock type and the bad geological body is 93% and 94% respectively, The accuracy of advanced geological prediction of TBM construction tunnel has been effectively improved, and good result have been achieved. The result show that in view of the high risk characteristics of TBM construction in urban hydraulic tunnels, the use of targeted comprehensive advanced geological prediction technology can effectively improve the accuracy of prediction, provide technical support for optimization design and emergency treatment measures, thus reducing construction risks and avoiding disaster accidents. It is worthy of wide application and promotion in related projects. This technology can provide reference for the design, construction and researchers of urban hydraulic tunnels.

As a core flow-releasing facility in hydraulic structures, the healthy operation of the spillway plays a critical role in maintaining dam stability and ensuring downstream flood control safety. Spillway reinforcement and reconstruction are key focuses of risk elimination and reinforcement in water conservancy projects. The spillway of Luotian Reservoir was taken as the research object to carry out upgrading and reconstruction design research targeting its operational status and existing issues. Through analysis, it is identified that the spillway has problems such as poor scouring resistance of the floor, a stilling basin failing to meet energy dissipation and scour prevention standards, and local high-steep unstable slopes. Accordingly, an overall reconstruction plan is proposed, including the reconstruction of the floor and reinforcement of the side walls in the inlet channel and tailrace channel, the integral reconstruction of the control section of the steep slope, the chute section, and the stilling basin, as well as the support of high-steep slopes. Verified by hydraulic design(discharge capacity, water surface profile, energy dissipation and scour prevention calculations, and rechecking of flow capacity of tailrace bridges and culverts) and structural design(calculations of side wall stability and stress, stilling basin anti-floating, and slope treatment stability), the reconstruction plan meets regulatory requirements, with good discharge and energy dissipation effects and safe and reliable structures.

Based on a large underground storage tunnel project in a extreme cold area, the numerical simulation of pollutants and temperature field during tunnel excavation is carried out. The three-dimensional numerical model of long tunnel excavated is established, and the three-dimensional flow field and temperature field are simulated by CFD method, and the rationality of the numerical simulation is verified. Accordingly, the wind field and CO migration and distribution rule in the tunnel under different ventilation modes are further simulated, and the influence rule of mechanical ventilation on the temperature field of the tunnel is analyzed. The simulation result show that the pollutant field near the working surface and the influence of external cold air migration should be considered at the same time in tunnel excavation in extreme cold regions. The compressed ventilation has a long discharge path and a longer time for pollutant concentration to reach the standard, and the smoke exhaust window takes a longer time for pollutant concentration to reach the standard. However, the main roadway is not affected by the cold air outside the tunnel, and the loose smoke at the entrance of the main alley will have a stable cooling and heat convection exchange area at the entrance of the roadway.The pollutants can be effectively discharged by using mixed ventilation, however, the negative pressure generated by the extraction fan will accelerate the injection of cold air outside the tunnel. Attention should be paid to the balance of the pumping air volume and the insulation of the entrance, so as to reduce the influence of cold air on the temperature field of the tunnel.

In urban underground water conservancy projects, the construction process of a rectangular shaft is a complex and crucial engineering task. This task plays an extremely important role in ensuring the stable supply of urban water resources, effectively preventing floods and draining water, as well as protecting and maintaining the groundwater environment. During the construction of the shaft, determining the layout and shape, as well as the dimensions of the shaft's cross-section, is a step that requires careful consideration. The decision on these factors is not only influenced by the functional use and construction conditions but must also take into account various aspects such as geological conditions, water inflow, the performance of hoisting equipment, production efficiency, and the setting of safety exits. Among these considerations, geological conditions are particularly critical as they directly relate to the form of the cross-section layout and the design of the support structure. Currently, in many water conservancy projects, commonly used cross-section shapes include circular, square, and rectangular. Among them, the circular cross-section is the most common due to its convenience in construction and maintenance and its high cross-section utilization rate. However, in certain specific geological conditions or urban spatial constraints, a square or rectangular cross-section may be more appropriate.

The risk assessment of harmful gases during the construction of underground caverns is an important component of construction safety management. However, due to the combined influence of multiple factors such as self diffusion, rock type, selection of construction machinery, ventilation scheme, etc., the risk assessment of harmful gases in caverns is often difficult to carry out. Based on this, big data monitoring of harmful gases and their influencing factors during tunnel construction was used, taking into account the multidimensional and nonlinear characteristics of the data. The eXtreme Gradient Boosting(XGBoost) ensemble learning algorithm is adopted to construct a risk assessment model for harmful gases in underground tunnels, and the Tree-structured Parzen Estimator(TPE) algorithm is used to optimize the hyperparameters of the model. By combining examples, the risk assessment result of harmful gases were predicted and the accuracy of the model was verified. The research result showed that the XGBoost model achieved an accuracy rate, recall rate, and F1 score of 85.8% for the risk assessment of harmful gases in underground caverns, demonstrating the model's accurate predictive ability. Compared with XGBoost, SVM, Decision Tree, and AdaBoost, the accuracy of the XGBoost model optimized by hyperparameters has been improved by 6.8%, 54.0%, 10.3%, and 100.9%, respectively. This proves that the model can more effectively implement the risk assessment of harmful gases in underground caverns, providing theoretical and technical guidance for construction safety management.

The influence of foundation pit excavation on the adjacent large-diameter fully prefabricated tunnel was studied. Through the analysis of the interaction between foundation pit excavation and tunnel structure, the effects of vibration, settlement and deformation of tunnel structure that may be caused by foundation pit excavation are discussed, and relevant risk control and mitigation measures are proposed. Based on the research method of theoretical analysis, numerical simulation and field measurement, this paper identifies the possible adverse effects and potential risks of foundation pit excavation on the existing large-diameter fully prefabricated tunnels, and provides important guidance for the risk management of related projects.

The underground powerhouse of a pumped storage power station is typically characterized by confined spaces and fully enclosed surroundings. In particular, the turbine section features a complex structural layout and restricted access routes, posing significant challenges for concrete construction and complicating the formulation of construction plans. Among these, the method of concrete placement is a critical step during pouring. Improper selection can lead to inefficiencies and resource wastage. Drawing on the concrete construction experience of the Luoning pumped storage power station, this study analyzes the sectional structure and characteristics of each layer within the powerhouse, evaluates the performance of applicable equipment, and considers recent advancements and trends in construction techniques and equipment utilization. Based on the specific conditions of each section, optimal combinations of equipment were selected to determine the most efficient concrete placement method. Overall, it is deemed both scientific and practical to adopt ground pumps and bridge cranes with concrete buckets for sections below the spiral case, while tower cranes are recommended for sections above it. As each layer of the powerhouse units varies, careful consideration of specific site conditions is necessary for flexible implementation. The findings and method ologies presented offer valuable references and systematic approaches for the analysis and determination of concrete placement strategies in similar projects.

With the increasing service life of rail transit tunnels and the continuous changes in the surrounding soil, structural defects in tunnels have become increasingly prominent, posing significant risks to tunnel integrity and the operational safety of rail systems. This study focuses on the reinforcement design method utilizing prefabricated composite profiles for rail transit tunnels, aiming to clarify their application performance and advantages in tunnel engineering. Through literature review and case studies, existing problems and limitations in current tunnel reinforcement design method ologies are critically evaluated. A novel reinforcement design approach based on composite profiles is proposed. The findings indicate that this method offers notable advantages in enhancing the structural stability and durability of tunnels. Furthermore, a quantitative classification mechanism for shield tunnel defects is established. Based on the tunnel defect composite index(TDCI), tunnel defects are categorized into five levels. Corresponding reinforcement schemes, including prefabricated composite profile reinforcement and pre-reinforcement strategies, are developed according to defect severity. Using tunnel section scanning data, prefabricated components of the composite profiles are manufactured and assembled on-site. These components are anchored and bonded to the tunnel lining through bolts and structural adhesive, followed by grout injection, to achieve effective reinforcement. This study provides robust technical support for the structural reinforcement of shield tunnels.

The secondary lining of water conveyance tunnels is a typical thin-walled, strongly constrained reinforced concrete structure. Currently, there is no specific technical code for crack prevention in thin-walled, large-volume concrete structures. Preventing cracks in tunnel secondary linings has long been a key technical challenge. Based on the Dianzhong Water Diversion Project, this study conducted experimental investigations and computational analyses on crack prevention technologies for tunnel lining concrete, focusing on crack formation mechanisms, concrete performance optimization, and temperature control measures. The result indicate that the primary causes of circumferential and irregular horizontal cracks in some tunnel sections are excessive concrete water content and significant temperature gradients between the concrete and its foundation. To reduce concrete water demand, the MB value of manufactured sand should not exceed 1.0 g/kg. If this threshold is exceeded, washing or adding antimud agents is recommended to mitigate the adverse effects of clay content in the sand. The crack resistance safety factor of tunnel lining concrete should be no less than 1.65. Among influencing factors, temperature during construction has the most significant impact on crack resistance. Under standard construction conditions, the minimum crack resistance safety factor typically falls below 1.65; therefore, it is necessary to control both the pouring and peak temperatures to minimize cracking risks. During construction in high-temperature seasons or when structural joints are excessively long, micro-expansion concrete with added magnesium oxide can be used. This ensures that the autogenous volume change at 28 days exceeds 30 × 10^-6, raising the crack resistance safety factor above 1.65 and effectively reducing the risk of cracking.

The tailwater steel liner is a crucial component of the tailrace system in hydropower stations, and the quality and efficiency of its installation directly impact the overall progress and quality of the project. Therefore, research on efficient on-site construction organization and installation techniques for tailwater steel liners holds significant practical value. The installation of the main unit's pre-embedded tailwater steel liner marks the beginning of the electromechanical installation phase and establishes the centerline reference of the unit. However, the narrow and complex environment within the machine pit, coupled with the large size and heavy weight of the tailwater steel liner, leads to difficulties in movement and assembly. Through effective coordination of procedures between units and rational design optimization to reduce process conflicts, the preliminary embedding work can be carried out efficiently and systematically, thereby saving construction time and labor costs. The use of custom-made rail-mounted transport trolleys for pipe section positioning overcomes the limitations of bridge crane constraints and the inconvenience of dragging pre-embedded anchor hooks, enhancing operational safety and improving the precision and efficiency of pipe section positioning and assembly. These optimized construction organization strategies and technologies ultimately achieve comprehensive improvements in project schedule, quality, safety, and overall benefits.

Due to the rock mass' s poor stability in the water-rich fault fracture zone, the large-scale and difficult-to-handle TBM machine jamming disasters often happen when TBMs pass through such regions. The jamming incident of an open TBM in a water conveyance tunnel located in Xinjiang was taken as an example to analyze the causes of local large deformation of the supporting structure and the convergence deformation characteristics of the tunnel surrounding rock near the main fault surface. Based on the analysis of on-site engineering geological conditions and structural deformation, it was determined that the jamming incident was caused by the rupture, expansion and deformation of the left and upper surrounding rocks under the influence of excavation disturbance, which exerted a large squeezing effect on the shield, causing the mutual friction between the surrounding rock and the shield greater than the TBM's maximum thrust. Through numerical simulation analysis, the fractured surrounding rock on the upper left side showed an overall mechanical response of sliding along the main slip surface of the fault besides volume expansion and deformation. Therefore, under the effect of water flow, the initial shield and steel arch were severely damaged. In addition, the simulation result show that as the jamming time increases, the scope and severity of the jamming will intensify. Specifically, the surrounding rock of the vault also gradually undergoes obvious expansion and deformation, causing the shield to be affected by the circumferential force within the scope of 270°. Based on the classic elastic foundation beam theory, the easily deformable range of the supporting steel arch was calculated, further explaining the severe deformation phenomenon of the steel arch and shield in this jamming case. Finally, according to the on-site construction conditions, domestic and foreign engineering experience, and the above-mentioned analysis of the jamming disaster breeding process, an efficient TBM release theory of "tight-injection-excavation" is proposed. After the dense steel arch and chemical grouting were implemented, a strong pressure-bearing arch effect was formed around the tunnel. With the subsequent excavation release technology, the TBM was successfully continuing operation.

The "red layer" in Yunnan exhibits characteristics of weak water permeability, strong hydrophilicity, susceptibility to softening upon exposure to water, and a tendency to disintegrate when submerged. Selecting an appropriate grouting process and parameters is crucial for establishing a continuous and effective anti-seepage curtain. Based on multiple engineering grouting tests, the orifice closed segmented circulation grouting method, along with parameters such as mixed grout, maximum grouting pressure not exceeding 1.0 MPa, single-row hole layout, and 1.5 m hole spacing, has been promoted and applied in production grouting. These measures successfully form a continuous and effective anti-seepage curtain. The implemented reservoir project has been operational since the closure of water storage. No leakage has occurred at the dam foundation or around the dam, and all requirements for anti-seepage have been met. This provides valuable engineering experience that can be referenced and promoted for similar projects.

A simplified theoretical method is proposed and stress-seepage coupled numerical modeling conducted to calculate the reduction effects of grouting zone thickness and hydraulic conductivity variations, under prescribed drainage condictions, on the external water pressure and internal forces of lining. The calculations reveal the following observations:(1)When the drainage flux is not so large, e.g. less than 4 m³/(d.m), the simplified theoretical method can be employed to calculate the reduction effects with less than 10% errors.(2)When the drainage flux is quite large, e.g. larger than 4 m³/(d·m), the simplified theoretical method can still correctly refelect the variation trends, but possibly with no smaller than 10% errors.(3)Only when there is drainage, can the grouting zone contribute to the reduction effects, otherwise it can only serve as an impediment to seepage.(4) Within certain limits, the larger the drainage flux, the larger the grouting zone thickness, and the smaller the grouting zone hydraulic conductivity, the more significant the reduction effects.

Thixotropic mud plays a vital role in pipe jacking construction, where its excellent thixotropic properties not only provide stratum support but also offer lubrication and friction reduction during pipe advancement. The physical properties and friction reduction performance of the mud are directly related to the efficiency and safety of the construction process. Considering the specific requirements of water-rich soft strata, a new thixotropic mud formulation was proposed using bentonite, soda ash, carboxymethyl cellulose(CMC), and a water-reducing agent. Physical property tests were conducted under different mud ratios to analyze the effects of the water-reducing agent and other components on the mud's viscosity, water loss, and water separation rate. A scaled model test was further conducted to investigate the friction reduction performance of the new thixotropic mud, and parameter normalization analysis was carried out based on stratum characteristics to identify the optimal mud formulation. The result show that the water-reducing agent can adjust the water-cement ratio and promote gel structure formation, thereby increasing viscosity, reducing water loss, and effectively inhibiting water separation. Compared with un-grouted pipe jacking, the new thixotropic mud reduced the friction coefficient by up to 77.1%, and by 38.5% compared to traditional mud without the water-reducing agent, demonstrating significant friction reduction. Pipe jacking in water-rich soft strata requires thixotropic mud with good permeability control and long-term stability. Therefore, the optimal formulation of 10% bentonite, 0.1% CMC, 0.2% soda ash, and 0.5% water-reducing agent was selected. The findings provide effective technical support for addressing poor grouting performance in pipe jacking construction in water-rich soft strata and offer significant application value.

Selecting appropriate seepage control schemes is a critical aspect of high arch dam design, influencing the long-term safety and economic feasibility of dam operation. To optimize various seepage control measures and schemes for high arch dams, a 240-meter-high concrete arch dam was used as a case study. A three-dimensional seepage simulation finite element model was established to simulate the three-dimensional seepage field of the high arch dam. Seepage simulations under different seepage control schemes were conducted for typical cross-sections, and the seepage pressure variation patterns of these sections were analyzed to reflect the sensitivity of different seepage control schemes to the dam's seepage field. The result indicate that: Installing drainage holes can effectively reduce uplift pressure. The installation of a curtain also helps to reduce uplift pressure, but the reduction is less significant compared to drainage measures. The drainage settings for the cushion pool and resistance rock mass are crucial, playing a significant role in reducing groundwater seepage pressure in the vicinity of the cushion pool. The installation of drainage hole arrays for the resistance rock mass and cushion pool can achieve good seepage prevention effects. On the basis, an optimized scheme for seepage control has been proposed, which holds significant reference value for similar projects.

Although soilbag reinforcement is an established environmentally friendly method for highway subgrade enhancement, its working behavior and the factors influencing its performance remain inadequately understood. Model tests were conducted on soilbag-reinforced highway subgrade subjected to cyclic vertical loads are conducted, considering various reinforcement layers, embedded depths, and cyclic load frequencies and amplitudes. It was found that the reinforcement, stress dispersion, and energy dissipation characteristics of the soilbags effectively reduce surface settlement, resilient deformation, and vibrations induced by cyclic loads. Increases in the amplitude and frequency of cyclic loads were observed to lead to greater surface settlement, resilient deformation, and acceleration responses in the soilbag-reinforced subgrades, with more significant reinforcement effects noted under higher load amplitudes and frequencies. It was also demonstrated that a decrease in the embedded depth of the soilbags and an increase in the number of reinforcement layers enhance the subgrades' ability to resist deformation and vibration. A reinforcement cushion composed of multiple layers of soilbags can significantly enhance the overall anti-deformation capacity and vibration reduction and isolation effect of the subgrade. Consequently, this reduces subgrade and pavement deterioration under heavy traffic loads.

Ultra-high-pressure injection grouting is one of the main method to improve the bearing capacity of foundations, in order to investigate the diffusion mechanism of ultra-high-pressure injection grouting, the simulation method combining particle flow(DEM) and computational fluid dynamics(CFD) is used, and the macroscopic and microscopic parameters of the particles are determined by triaxial tests in the laboratory and numerical simulation tests, and the simulation method is verified by similar model tests. The validity of the simulation method was verified by similar model tests. Based on this, the numerical test of UHP injection grouting was carried out under different injection pressures of 20~60 MPa to monitor the changes of injection range, porosity and fluid pressure. The result show that the UHP jet grouting reinforcement process can be divided into three stages: cutting and wrapping, compression and tightening, and large-scale vortex cutting and replacement. With the increase of injection pressure, the injection distance increases approximately linearly, but the width of the cavity may be the same under different pressures; the peak value of the porosity of the soil around the cavity in the injection process is closely related to the shape of the cavity formed; in a very short period of time at the beginning of the injection(within 0.05) the soil body has appeared to have a multi-stage splitting phenomenon, and the fluid pressure is a significant change in the form of a stair-step; with the increase of the pressure, the vortex cutting and stirring of the soil body formed by the jetting will With the increase of pressure, the vortex cutting mixing soil formed by jetting will occur in advance, and there may be a critical pressure value(30 MPa), which can provide a certain reference for the actual project.

For land reclamation of soft soil, common method include the use of prefabricated vertical drains combined with surcharge or vacuum preloading. However, these method are often time-consuming and risky. To improve efficiency and reduce costs, new technologies are needed. Recently, prefabricated horizontal drains(PHDs) combined with vacuum preloading have been developed and tested in field experiments. A a solution was proposed for soft soil consolidation using prefabricated horizontal drains, based on an elliptical cross-section and the equal strain condition. The method is compared with both the Chai's method and the finite element method(FEM). The result show a strong agreement between the proposed method and FEM result. Additionally, the nominal reduction coefficients of this method, f^*_a and f^*_p, align with the coefficients from Chai's method, f_a and f_b. Field experiment data are also used for comparison, demonstrating that the proposed solution effectively simulates the vacuum consolidation behavoiur using PHDs. The method offers a promising alternative to traditional ones by potentially saving time and reducing the risks involved in land reclamation.

The eastern section of the Gongming Reservoir-Qinglinjing Reservoir Connection Project is located in the west side of the Longgang Karst Basin in Shenzhen near the Dongguan boundary. Engineering investigation reveals 6 sections of carbonate rocks.The age of each section of carbonate rocks is controversial. In order to clarify the stratigraphic age of carbonate rocks and analyze the soluble characteristics of rock groups, it is necessary to study the stratigraphic age of each section of carbonate rocks. The technical path of "regional stratum-lithology combination-rock mineral composition and fossils" from macro to micro is adopted for comparative analysis and research. Firstly, the regional strata of the project area are studied, and the stratigraphic age of each section is preliminarily determined. Then, the lithological combination of carbonate rocks in each section is compared and analyzed to further clarify the stratigraphic age of carbonate rocks in each section. Finally, the rock mineral composition and biological fossils of each section are compared and reviewed. Through comprehensive research and analysis, the stratigraphic age of carbonate rocks in each section involved in the Gongming Reservoir-Qinglinjing Reservoir Connection Project was clarified.The determination of the stratigraphic age should be based on the study of regional geological data, The result show that the age of carbonate strata in Longgang karst basin of Shenzhen is complex, combined with the comprehensive comparison and analysis of the lithology revealed by the survey.

Taking the Yangtze River crossing section in Wuhu Chengnan tunnel as research background, the coupled hydro-mechanical numerical model was utilized to study the deformation and seepage responses of anisotropic surrounding rocks under the action of tunnel excavation and river seepage. The influences of dominant-developed microcracks inclination, river level, and supporting water pressure on tunnel excavation responses were analyzed. The research result showed that the deformation induced by underwater tunnel excavation was mainly determined by river seepage action. Withdrawal of supporting water pressure would lead to excessive deformation of the surrounding rocks with safety risks, which was more obvious with the increase of river level. The tunnel excavation-induced deformation was also affected by the anisotropic structure of surrounding rocks and supporting water pressure. With the increase of dominant-developed microcracks inclination, the settlement of surrounding rocks in arch roof direction first increased and then decreased. The smaller the microcracks inclination, the greater the water pressure obviously decreased region around the excavated tunnel, as a result larger underwater-ground subsidence scope would be triggered by river seepage action. With the increase of supporting water pressure, the excavated-induced deformation around the tunnel gradually decreased, but excessive supporting water pressure would cause significant ground uplift displacement. It's of importance to select suitable supporting water pressure, but it was influenced by the anisotropic structural characteristic of surrounding rocks.

The Banmiao underground pumping station in the Gongming Reservoir Qinglinjing Reservoir Connection Project has a large scale of underground caverns, and complex geological conditions, which pose many challenges to the excavation and support design of the project. Numerical simulation method were used to investigate the excavation construction, support parameters, key blocks, and other aspects of the underground pumping station caverns. The numerical result showed that the geostress in the underground pumping station caverns is relatively low, and the direction of σ₁ intersected with the long axis side wall of the pump room by about 14 °. After applying systematic support, the deformation and plastic zone of the surrounding rock around are significantly reduced. Reducing the density of bolt(spacing of 1 m × 1 m → 1.5 m × 1.5 m) has a certain impact in the area of fault F1, but it is not significant in other areas; The areas with high stress on bolts and cables are mainly located in the areas of fault F1 and alteration zones; Based on the joints' information in boreholes, it is found that all of the potential blocks belong to infinite blocks using the Block Stereographic Projection Method. Seven large(> 180 m³) random blocks were found during the search, and all random blocks had a safety factor greater than 2.0 after considering anchoring support measures, meeting the requirements for the block safety factor.

In order to study the rock stability of semi-diagenetic tunnel in strong water-rich and weakly cemented fine sand, based on the fluid-solid coupling theory, taking the Wangjiazhai tunnel as an example, the seepage field, displacement field, stress field variation law and initial support stress characteristics during tunnel construction are analyzed. The result show that:(1) When considering the coupling effect, the maximum subsidence value of the tunnel vault reaches 12.6 mm, and the horizontal displacement of the tunnel body reaches 4.07 mm; regardless of whether the fluid-solid coupling is considered, the distribution characteristics of the contact stress between the surrounding rock and the initial support are similar; the pressure in the surrounding rock, taking into account the fluid-solid coupling effect, is greater than that without taking into account the fluid-solid coupling effect.(2) During tunnel excavation, the pore water pressure map is roughly funnel shaped. The contours of the pore water pressure values near the palm face are dense, with obvious seepage effects.(3) The simulation result show that the underground seepage gathers to the excavation surface, which is consistent with the occurrence of groundwater and inrush in the actual excavation of the tunnel.(4) According to the calculation result of seepage, displacement and stress after the excavation of the simulated tunnel, corresponding preventive measures are taken in the subsequent tunnel construction process to ensure the construction progress and safety of the project.It shows that it is feasible to simulate and analyze the stability of surrounding rock of water-rich tunnel by this method, which provides a theoretical basis for the stability analysis and preventive treatment of surrounding rock of water-rich tunnel.

The effect of load(S) and the resistance of the structure(R) in the probabilistic limit state design method are two independent variables, which are for the water coming from the buildings such as industrial and civil buildings, bridges, etc., to meet the requirements that the load and the structural bearing capacity are independent of each other, but for the tunnel and underground engineering, they do not meet the conditions that are independent of each other, the surrounding rock load of the tunnel is closely related to the resistance of the structure, and the load increases with the increase of the resistance of the structure, therefore, it is necessary to follow the correlation between the load and the resistance. Modify the probability function of the limit state design method.

Pile foundation is the foundation part of large buildings and infrastructure, and its safety performance directly affects the safety of the whole structure. In this paper, a three-dimensional pile-soil model is constructed by numerical simulation to simulate its mechanical response under different loads. The settlement behavior, axial stress distribution of pile body and the change law of pile-soil stress ratio are analyzed. The result show that:(1) With the increase of pile length, the pile tip settlement shows a decreasing trend, especially when the pile length reaches 33.4 m and is embedded into mudstone layer with strong bearing capacity, the pile tip embedding effect is significantly enhanced, resulting in a decrease in pile tip settlement. The difference between the settlement of raft center point and pile top surface increases with the increase of pile length, which reveals the important load regulation function of mattress layer.(2) When the pile length is short, the maximum axial stress is located at a certain distance below the top of the pile, and spreads along the pile body with the increase of load; For longer piles, the axial stress of pile bottom is larger, and the maximum axial stress point gradually increases with the increase of load. When the pile end is embedded in the strongly weathered mudstone layer, the axial stress distribution shows a “W” shape pattern, which reflects the importance of the embedment effect between the pile end and the rock.(3) With the increase of pile length, pile foundation can still maintain a high bearing capacity under large loads, but its growth rate will gradually slow down after exceeding a certain threshold, indicating that there is an upper limit of the bearing capacity of pile foundation.

The geological conditions along the Luotian Reservoir-Tiegang Reservoir water conveyance tunnel in Shenzhen are complex. The main tunnel line is adjacent to the Yulyu medium-to-high-temperature hot spring, which has a flow rate of approximately 1.5 L/s and a maximum temperature of 66~68℃. The genesis of the hot spring remains unclear, and the potential mutual impacts between the hot spring and tunnel construction require focused study. By employing surface geophysical prospecting, drilling, geothermal temperature testing, hydrochemical and isotopic analyses, this study investigates the formation mechanism of the Yulyu hot spring and evaluates its potential impacts on the tunnel project. The tunnel excavation validated the accuracy of the analytical result. The findings indicate that the geothermal water originates from atmospheric precipitation, with a recharge elevation of 102-169 m. The recharge area is identified as the northern slope of a low hilly region south of the hot spring, situated within a granite zone bounded between the southern plate of the Yulyu Fault and the northern plate of the Huangcaokengding Fault. The recharge water circulates deeply along secondary faults and fracture-dense zones, ascends via thermal convection along the Yulyu Fault, and emerges at structurally weak surface locations to form the hot spring. The Luotian-Tiegang water conveyance tunnel route avoids the deep cyclic seepage field of the Yulyu hot spring's recharge, flow, and discharge pathways. The project construction exhibits minimal impact from the Yulyu hot spring and its geothermal activity, nor does it adversely affect the hot spring itself.

With the rapid development of municipal infrastructure construction, crossing between new tunnels and existing projects is becoming more common. The shield tunneling method will inevitably cause some disturbance to the surrounding strata, which leads to the instability of the line and threatens its normal operation. In order to explore the influence of shield method on bridge pile foundation, and put forward some solutions with reference significance. Based on the Hongshankou Bridge project of the second phase of Tuan Ninth-phase water transmission tunnel under the Beijing Fifth Ring Road in a short distance, after evaluating the deformation control technical indicators that Hongshankou bridge should meet, the design scheme of lateral tunnel bridge piles is proposed, and the three-dimensional whole process construction simulation is carried out by Midas/GTS to determine whether the bridge structure meets the technical indicators. The result show that the influence of construction on the stability of Hongshankou bridge pile foundation can be reduced by adopting the design scheme of grouting with mud effect, deep hole grouting in the tunnel and strengthening the water sealing capacity of the second lining. By comparing the deformation value of Hongshankou Bridge in the construction process with the control technical index obtained by Midas/GTS simulation, the result show that the structural safety of Hongshankou bridge will not be affected under normal construction conditions of TuanninII water transmission tunnel. The research result can provide reference for the construction design of similar projects.

As the core equipment for flexible peak regulation in power systems, the performance of pumped storage power stations directly affects the stability of the power grid and the efficiency of energy utilization. The impeller, as the key component of the pump-turbine, plays a critical role in bidirectional energy conversion. In pump mode, the impeller converts electrical energy into the potential energy of water; in turbine mode, it transforms the potential energy of water back into electrical energy. This bidirectional operating characteristic imposes stringent requirements on impeller design: it must simultaneously ensure high head and high efficiency under pump conditions, as well as stable operation across a wide flow range under turbine conditions. The hydraulic performance of the impeller directly determines the unit's energy conversion efficiency(accounting for 70~80% of the total efficiency) and operational stability(including issues such as pressure pulsation and vibration). The structural characteristics of the impeller were analysed and an in-depth discussion on the principles of hydraulic design, optimization method, key parameter analysis, and practical performance evaluation was carried out. The objective is to provide detailed and scientific references for the design and operation of pumped storage power stations.

[Purpose] In order to clarify the flow characteristics of the lateral inflow forebay of Dazhaihe-Banzha main canal pumping station at different characteristic water levels, and to put forward the control measures of the flow field of the forebay and the operation scheme of the unit at the lowest water level, so as to provide technical reference for the safe, efficient and stable operation of the pumping station unit. [Methods] The method of hydraulic physical model test was used to carry out hydraulic physical model test on the diversion river, forebay and open inlet pool of pumping station. The flow field of forebay with or without flow control measures was analyzed, and the flow field characteristics of forebay with different start-up schemes at the lowest water level were analyzed. [Results] The result showed that after adopting the rectification measures of non-equal gradient arc-shaped diversion piers, the average velocity distribution uniformity of the surface layer of the forebay with the full opening of the unit at the design water level was 85.86%, the average velocity distribution uniformity of the middle layer was 88.75%, and the average velocity distribution uniformity of the bottom layer was 85.42%. The high-speed area became smaller and the flow pattern improved better. At the lowest water level, if the unit is fully started, the flow pattern of the forebay is further deteriorated, and the unit vibrates. The flow field of the 1 ~# unit deteriorates most significantly and the vortex band inside the intake pool. [Conclusion] At the lowest water level, it is recommended to open 3~# unit when the pump station is 0.2 times the load flow. When the pump station is 0.4 times the load flow, it is recommended to open 3~# and 4~# units, and the pump station is 0.6 times the load.

The development of hot dry rock(HDR) provides a zero-carbon and negative-carbon solution for China's energy industry. Hydraulic fracturing is one of the main means for building the geothermal reservoirs. Different from sedimentary rocks such as coal and shale, granitic hot dry rock is igneous rock, in which the geologically discontinuous rock, such as veins and rock interfaces are developed. Therefore, it is difficult to predict and control the propagation geometry of the hydraulic fractures when intersecting with these discontinuous rocks. Based on XFEM, the investigations were conducted on the influence mechanism of the discontinuous rock on the propagation path of hydraulic fractures in granite. The result show that: The greater the difference in tensile strength and Young's modulus between rock matrix and the discontinuous rocks, the hindrance effect on the propagating hydraulic fracture is more obvious. A large difference in Poisson's ratio is beneficial for hydraulic fractures to penetrate the discontinuous rock. For the granite with dense matrix, a smaller injection rate is beneficial for the hydraulic fracture to penetrate the discontinuous rock. When the maximum in-situ stress is consistent with the direction of hydraulic fracture initiation, a larger in-situ stress difference coefficient is beneficial for hydraulic fractures to penetrate the discontinuous rock. Under the same geological and engineering parameters, hydraulic fractures are more likely to penetrate the rock interface rather than rock veins. At the same time, the difference in the cementation degree of the discontinuous rock can also affect the propagation path of hydraulic fractures in granite.

Pier foundation scour is one of the leading causes of bridge failure, highlighting the urgent need for practical and effective scour protection strategies to ensure the structural safety and serviceability of bridges under flood conditions. A bridge scour protection design that combines grouting and riprap, was proposed and evaluates its effectiveness compared to single protection approaches. The reliability of scour simulations conducted with Flow-3D was validated by replicating the Melville experiment. Subsequently, clear-water scour simulations were carried out to analyze the critical initiation shear stress of the grouted regions around the pile foundations. In parallel, fixed-bed scour simulations were used to evaluate the turbulence-modulating effects of riprap based on flow velocity distribution around the pile. A comprehensive simulation of the combined protection method was then performed to assess its impact on scour depth and pit morphology. The comparative analysis revealed that the combined grouting and riprap protection significantly reduced scour depth, altered flow patterns more effectively, and led to more favorable scour pit geometries than either grouting or riprap alone. The integrated use of grouting and riprap provides a promising solution for pier foundation scour protection.

Offshore wind turbine pile foundations are subject to various degrees of scour under the combined action of waves and currents, which reduces the pile-soil contact depth and threatens the structural safety of wind turbines. Existing standards primarily specify hydrodynamic and structural parameters of wind turbine foundations but lack detailed classifications of seabed types. Field investigations indicate that seabeds composed of very fine sand and silt with varying relative densities and permeabilities exhibit significantly different scour depths.To achieve high-accuracy scour depth prediction, this study conducts scour tests on pile foundations across different seabed types and employs neural network models to analyze the scour evolution in seabeds with distinct characteristics. Sensitivity analyses are performed on three main categories of parameters influencing pile scour: hydrodynamic parameters, pile foundation parameters, and seabed geotechnical parameters.Test result and sensitivity analyses reveal that within the seabed geotechnical parameters, the internal permeability of seabed sediments is the most critical factor affecting scour development. The underlying mechanism is that seabeds with low permeability coefficients fail to form sufficient internal fluid pathways, resulting in reduced external fluid drag and less sediment mobilization, which ultimately leads to shallower scour depths.Based on these findings, three passive protection countermeasures aimed at reducing seabed permeability are proposed, providing valuable references for scour prediction and passive protection strategies for offshore pile foundations under complex marine conditions.

The Gongming Reservoir-Qinglinjing Reservoir Connection Project is one of the supporting projects of the Pearl River Delta Water Resources Allocation Project within Shenzhen city, serving as a crucial component of Shenzhen's backbone water network. The Banxuegang-Miaokeng Pump Station adopts an underground pumping station design, comprising two pump units: the Banxuegang unit supplies water to Banxuegang Waterworks(2 operational + 1 standby), while the Miaokeng unit serves Miaokeng Waterworks(2 operational + 1 standby). The station is equipped with six horizontal centrifugal pumps in total(4 operational + 2 standby), and includes a dedicated connecting pipeline for Miaokeng Waterworks to enable gravity-fed water supply from Qinglinjing Reservoir. The main pump chamber features excavation dimensions of 118.3×17.0×29.85 m(L×W×H). Considering Shenzhen's urban spatial constraints and stringent environmental requirements, this paper elaborates on the comprehensive design philosophy of the Banmiao Pump Station, detailing key technical aspects including: overall station layout planning, arrangement design, excavation stability control, underground drainage solutions and safety monitoring system design.

Focused on the measuring uncertainty of ultrasonic flowmeters installed at hydropower plants, the sources of measuring errors of ultrasonic flowmeter installed in hydropower stations are analyzed firstly in this paper, then a solution of site calibration is proposed which consist of actual measurement of geometric parameters, disturbance simulation and comparison to absolute discharge measurement. Site calibration is applied on two Francis turbines in a large hydropower station in China. Calibration result above 50% rated discharge show that, the deviation of ultrasonic discharge after calibration to absolute measurement is below 1% and also the deviation is less than 1% of rated discharge. The measuring accuracy of ultrasonic flowmeter is improved significantly compared to the deviation above 2% before calibration. Study and practice in this paper provides a solution to proceed site calibration on ultrasonic flowmeter in hydropower stations which is helpful for the reliable operation of flow monitoring.

The basic principle of index test is introduced firstly in this paper, then the difficulties to determine the correct flow differential coefficients on site test to measure and evaluate the discharge and efficiency of prototype turbine by the previous research are concluded. An improved method of index test is proposed to evaluate the prototype turbine efficiency with the measured relative efficiency determined by index test result at different net heads. The turbine efficiency is evaluated by the comparison between the measured result and the predicted values as the relative efficiency. Finally, this improved method is applied to a Francis turbine of a large hydropower station in China. Test result show that the relative efficiency of the improved index method is close to the predicted values from the turbine manufacturer and accepted by the all parties of the project. This improved method is an available solution and helpful reference to proceed index test for prototype turbine. However, due to the lack of accurate discharge, this improved method may be applied to evaluate the guaranteed values and penalties in the contract only when an agreement is made by all parties of the project.

Focused on the influence of the energy distribution in thermodynamic efficiency test on turbine, the basic principle of thermodynamic method is firstly introduced in this paper. Hydraulic efficiency of turbine is worked out based on the first law of thermodynamics accordingly. Numerical calculation is performed on a large-scale prototype turbine then site measurement is carried out. Study result show that energy distribution at high-pressure section is circularly symmetrical and sampling measurement may obtain reliable result. Energy distribution at low-pressure section is rather asymmetrical and is affected obviously by the operation condition. As more as possible measuring points are needed at low-pressure section to obtain the average energy. The heat exchange of the sampling device during thermodynamic measurement need specific measures to get a correct specified mechanical energy of turbine.

As a major economic and energy province, Sichuan is located at the core intersection of the Western Development Strategy and the construction of the twin-city economic circle in Chengdu and Chongqing, and is accelerating the construction of a national strategic hinterland and a key industrial backup area. As the capital of Sichuan Province and the power load center of the southwest, Chengdu has a maximum load of more than 20 million kW, but the emergency standby and peak adjustment power supply is only 4 million kW. The problem of "hollowing-out" of the power supply is prominent, and the safety of the power grid faces serious challenges. The pumped storage power station is equipped with comprehensive functions such as peak, peak adjustment, phase adjustment and black start, which is the key support to ensure the stable operation of large power grids. Based on the current situation of Chengdu's power grid, this article analyzes the formation mechanism and coping strategies of power supply "hollowing-out" in combination with the development trend of grid, source and load, and focuses on the key role of pumped storage power stations in alleviating the contradiction between power supply and demand in Chengdu and enhancing the resilience of the power grid.

In order to solve the problem of sediment accumulation in runoff hydropower stations and ensure the safe operation and power generation efficiency of hydropower stations, the river conditions, overall layout, experimental research, and operational method that affect the sand prevention and drainage of engineering power stations were analyzed and evaluated based on actual situation of the design, construction and operation monitoring of sand prevention and drainage facilities at Xinglong Hydropower Station on the Han River, which can provide references for similar engineering designs.

Caohai is a semi-enclosed shallow water lake, relies predominantly on wind fields for its hydrodynamics, resulting in slow water flow velocities and weak water exchange capacities. Consequently, pollutant deposition has led to a deteriorating water quality situation. In an effort to improve water quality, the Niulan River-Caohai Water Diversion Project uses the high-quality water source of the Niulan River to replace the existing water in the Caohai Lake, but the drainage scheme of the project is relatively simple and the water replacement efficiency is not ideal. To enhance water replacement rates and minimize water resource wastage, based on the collection and analysis of field measurement data, a three-dimensional wind field model for the Caohai Lake basin and a two-dimensional hydrodynamic-convection diffusion coupled model were established. This model was utilized to investigate the improvement effects of water replacement efficiency under various inflow forms and engineering measures. The research findings indicated:(1) the presence of surrounding mountainous terrain result in uneven distribution of wind fields across the lake surface.(2) Influenced by wind, the lake's flow field is complex, with multiple circulation patterns that hinder the water replacement process.(3) Removing certain guide flow barriers and installing 7.5 kW submersible propellers can play a “clear water introduction and pollution pushing” role, optimizing the water replacement process. This approach holds certain reference value for the optimization of water diversion project.

The hydropower station projects are developing rapidly in China. At the same time, the fire risks they face are also increasing. To study the diffusion characteristics of fire smoke in the main powerhouse of a hydropower station, a numerical model of the same size was constructed based on a typical large-scale hydropower station project in China. This research is carried out for four fire scenarios: a fire at the end of the generator floor, a fire in the middle of the generator floor, a fire in the middle of the busbar floor, and a fire in the middle of the turbine floor. The smoke diffusion process and spread characteristics under different fire scenarios are analyzed and discussed. The research shows that when a fire breaks out at the end or in the middle of the generator floor, the smoke cannot diffuse to other floors. However, when a fire breaks out in the middle of the busbar floor or the turbine floor, the smoke will fill the entire space of the main powerhouse eventually. Nevertheless, the diffusion mechanisms of smoke among different floors vary under different scenarios. The research conclusion can provide theoretical and technical guidance for fire smoke prevention, control, and emergency response in the main powerhouses of hydropower stations as well as extra-large spaces.

The dam group system is composed of multiple chain structures in series and parallel, the transmission process of disaster risk in the dam group system has a significant chain effect. On the risk chain transmission mode of the dam group system, the risk impact model between adjacent units of dams into the dam group is elaborated. A risk chain effect analysis and evaluation model for dam groups of small and medium-sized watersheds is constructed, and finally, the risk chain effect coefficient and risk level between dams are determined through the analytic hierarchy process and expert system synthesis. The method proposed provides a new path for risk assessment and management of dam groups.

The frequency of extreme events in the context of global warming, increased population density and greater ecological fragility have made our country more vulnerable to extreme events. In most cases extreme events do not occur in isolation, but through the interaction of different meteorological factors. Compound disasters are usually more hazardous than single disaster events and are driven by multiple influences. Based on literature review and combined with the actual of National Climate Center, the current response measures of the power distribution network on extreme events and the research progress of compound disasters are discussed. At present, most of the studies on the impact of power distribution network disaster prevention and mitigation are limited to the single disaster. There is a lack of research on the intrinsic connection of compound disasters, the disaster-causing mechanism, the evolution of the law, and the impact of the industry. And there is very little research on the characteristics of the spatial and temporal distribution of compound disasters and their variabilities in the distribution network area. The study of compound disaster risk for the power distribution network is still in the blank stage of the hazardous effects of disaster. Therefore, some thoughts and suggestions will be put forward from the perspective of the spatial and temporal evolution characteristics of compound disasters and their impact on the current status of the power distribution network's ability to prevent and mitigate disasters, highlighting the necessity and urgency of researching the impact of compound disasters on the electric power industry, and providing a scientific basis for preventing and responding to compound disasters to reduce their impact on electric power infrastructures.

Instability and improper protection of the secondary excavation about the slope is one of the key challenges during the reconstruction and expansion of the existing road. The excavation of rock and soil will cause secondary disturbance to the existing slope. Variations in strength parameters of rock and soil materials is found as a result of the excavation unloading. This unfavorable condition often cause the stability of the slope. Adopting the traditional design concept, the existing codes treats rock and soil as ideal elastic-plastic materials without considering the unloading deterioration effect of slope rock and soil materials. However, this practice is not consistent with practical projects. In this paper, based on the secondary development of FLAC^3D, the embedded program for unloading deterioration effect of rock and soil materials during the slope excavation is developed and realized. Then, the stability analysis of high-steep slope for the processing considering the deterioration of rock and soil mass parameters caused by unloading is performed. The result show that the maximum unloading amount in the slope excavation process can reach about 90%. After considering the unloading deterioration effect, the potential failure mode and safety factor change process of the slope during the excavation process are quite different. The unloading deterioration effect greatly reduces the rock mass parameters of the new slope, resulting in the failure of shallow landslides in the local area of the new slope in the later stage of slope excavation; compared with the ideal elastic-plastic slope model without considering the unloading deterioration effect, after considering the unloading deterioration effect, the safety factor of the slope decreases in different proportions, and the gap between them can reach about 20%.The research on the excavation of high and steep slopes considering the effect of unloading degradation can provide a reference and theoretical basis for the excavation design and stability control of high and steep slopes during construction.

In order to explore the similarities and differences in the development of engineering geological investigation codes in the water conservancy and railway, highway industries since the 1st Five-Year Plan until now, a comparative analysis method is used to analyze and compare from five aspects: development mode and scope of application, existing projects, unfavorable geological condition, and provisions for ancillary construction projects. The results show that:(1) The engineering geological investigation codes in the water conservancy industry has developed in a dispersed manner, while in the railway and highway industries, it has developed in a convergent manner, with different development ways;(2) The scope of application of the Code for Engineering Geological Investigation of Water Resources and Hydropower is gradually narrowing for medium-sized projects, while the Code for Geology Investigation of Railway(Highway) Engineering is gradually expanding in terms of applicable types(grades), and there are significant differences in the provisions of the scope of application;(3) The water conservancy regulations implemented after the reform and opening up and the current highway regulations do not have investigation regulations for existing projects, while the railway codes have had corresponding provisions in place for 39 years, and there are significant differences in the provisions for existing projects;(4) The water conservancy industry codes have many shortcomings in the provisions for unfavorable geological conditions, while the railway and highway industries codes use professional terminology and have specific codes and chapters to guide investigation work, with significant differences in the provisions for unfavorable geological conditions;(5) The water conservancy industry codes implemented from 1978 to the present do not have provisions for ancillary construction projects, while the railway and highway industries codes have had corresponding provisions in place for over 20 years, and there are clear differences in the provisions for ancillary construction projects. The results indicate that some of the regulations in water conservancy standards are not as good as those in railway and highway standards, and it is necessary to develop a Code for Engineering Geological Investigation of Water Resources and Hydropower that is suitable for the high-quality development of water conservancy in the new development stage.

Once the near-dam reservoir bank slope becomes unstable and collapses, it will inevitably have a significant impact on the adjacent hydraulic structures and the surrounding environment. Conducting safety monitoring and risk early warning for the near-dam reservoir bank slope after instability and failure is of great significance for ensuring the safe operation of hydraulic structures. Therefore, this paper proposes a set of safety monitoring and risk early warning method for the near-dam reservoir bank slope. Deformation monitoring quantities, their deformation rates, and the safety factor of the slope are selected as the key monitoring indicators for the safety of the near-dam reservoir bank slope. A monitoring classification standard of "three-level early warning(normal, mild abnormal, abnormal) + one-level emergency" is established. An overall safety early warning index for the near-dam reservoir bank slope based on the Copula function and the fusion of multi-point displacement monitoring information is constructed. Based on the analysis of landslide-induced waves, relying on the relationship between the landslide volume and the wave height in front of the dam and the allowable wave height of the automatic regulation output system of the hydropower station, a risk classification and early warning level for the operation and dispatching of the hydropower station after the instability and failure of the near-dam reservoir bank slope is established. This method not only considers the safety monitoring issues of the near-dam reservoir bank slope itself, but also takes into account the downgrading and down-classification of the landslide-induced wave risk during the transmission process after the slope instability and failure. It can provide reference and guidance for the safety monitoring and risk early warning of the near-dam reservoir bank slope.

The growth and interweaving of plant roots in three-dimensional space can significantly enhance the mechanical properties of soil. A numerical simulation method is used to construct two-dimensional and three-dimensional analysis models of complex root-soil complex from the perspective of two-dimensional and three-dimensional calculation differences, respectively, to study the change law of soil and root displacement under stepwise pull-out and horizontal coupling loads. To reveal the interaction mechanism of complex root-soil complex. It is found that complex root system can limit soil deformation more effectively than single root system. Due to the increase of root-soil interface area, the soil consolidation performance of three-dimensional complex root system is better than that of two-dimensional simple distributed root system. Compared with 2D roots, the sharp change of displacement line under 3D complex roots appears at higher load values, and the calculated pull-horizontal coupling load of 3D roots is larger than that of 2D roots. The displacement contour of the three-dimensional root system tends to be triangular with the increase of load, because the three-dimensional root system provides additional anchorage points, which changes the displacement mode.

Complete rock and cracked rock will produce different forms of new cracks under cyclic loading. It is of great significance to study the crack evolution process of different types of rock to ensure the safety and stability of rock mass structure. Based on acoustic emission(AE), resistivity and DIC monitoring technology, the evolution process of rock cracks is monitored from the perspective of acoustic, electrical and optical multi-physical fields. The results show that the peak strength of intact rock under uniaxial compression is basically the same as that under uniaxial cyclic loading and unloading. The failure mode of the former is tensile failure and the latter is shear failure. The peak strength of pre-cracked rock under cyclic loading decreases with the increase of the number of cracks. The failure mode of single and double crack rock is tensile failure. In the cyclic process, the acoustic emission count reflects the initiation state of rock cracks from a microscopic point of view. It is more in the loading stage and less in the unloading stage, which indicates that the initiation of microcracks basically occurs in the loading stage. Rock resistivity reflects the connectivity state of rock cracks from a macro perspective, which has a certain correlation with rock strain, that is, the peak value of resistivity corresponds to the valley value of strain and the valley value of resistivity corresponds to the peak value of strain. At the same time, the evolution process of new cracks in different types of rocks was obtained based on DIC monitoring. Based on a variety of monitoring angles, the crack evolution process of rock under cyclic loading is explored, which is of positive significance for the subsequent study of rock damage characteristics.

The failure mode of soil with limited width behind a rigid retaining wall differs from the classical Coulomb theory. Position and form of the slip surface are crucial factors affecting the calculation of earth pressure. This study investigates the active failure modes of limited soil to provide basis for the theoretical research on active earth pressure. Taking the TT mode as an example, the study uses a self-made model to conduct active failure tests on cohesion soil. The digital image method is employed to collect and analyze the soil images during the testing process, and the result are compared with numerical simulation result to study the of the active slip surface in limited soil. The result show that the active failure slip surface in limited soil is a “broken line” passing through heel of the wall, and the slip surface is closely related to the width-to-height ratio and the internal friction angle. The result indicate that:(1) The smaller the width-to-height ratio, the more segments the slip surface has, the larger the initial rupture angle of the soil, and the steeper slip surface becomes. The critical width-to-height ratio for limited soil is 0.49.(2) The smaller the internal friction angle, the more the slip surface has, and the smaller the rupture angle of the slip surface. The critical internal friction angle for limited soil is slightly greater than 43.1°.(3) The active earth pressure in limited soil is generated by the “triangular” sliding mass on the left side of the slip surface, which less than the earth pressure of the trapezoidal sliding wedge in Coulomb's theory. The width-to-height ratio and the internal friction angle of the fill are important factors affecting the failure mode of limited soil, and they are indispensable considerations for determining whether the soil behind the wall is in a limited or semi-infinite.

Buttressed retaining wall can effectively prevent the unstable movement of soil filling. In order to obtain the influence of soil filling on the bearing deformation law of buttressed retaining wall, this paper studies the deformation stability of buttressed retaining wall under different filling thicknesses, and discusses the influence law of the filling thickness on the displacement of the retaining wall and the distribution of internal forces of the structure. The result show that:(1) When the thickness of the filling is low, the horizontal displacement at the top of the retaining wall increases with the increase of the filling amount. The horizontal displacement at the bottom of the wall continues to increase with the increase of the filling amount, and the pressure at the bottom increases, so there is a risk of tilt.(2) The internal force change of the retaining wall is analyzed, and it is found that the lateral earth pressure and internal shear stress of the retaining wall increase with the increase of the filling height. Especially in the rib section, the shear stress reaches a peak at a certain position. In addition, the shear stress distribution is closely related to the displacement mode of the retaining wall, and the retaining wall may rotate and move, resulting in the redistribution of internal stress. The design strength and layout of the floor are very important to disperse the soil pressure and reduce the shear stress concentration.(3) The increase in the thickness of the fill causes the internal stress level of the retaining wall to rise, especially in a certain position below the ground in front of the wall, the stress reaches the maximum value. The stress at the base is relatively small due to the dispersion of the foundation. During the design, it is necessary to pay attention to the influence of the change of fill thickness on the overall mechanical properties of the retaining wall to ensure that the structure is still stable enough under the most unfavorable conditions.

In order to solve the deep foundation excavation causes nearby existing station produces large deformation problems, using finite element software, grouting is carried out in the stratum between the deep foundation excavation and the existing station, push the subway station structure to the inside of the foundation excavation, thus the horizontal displacement of the station is controlled within a smaller target value. Different grouting positions are studied and three grouting method are proposed, which are through-length grouting, segmenting grouting and multi-point grouting. Through-length grouting means that the grouting amount per unit length remains the same from top to bottom in the whole grouting range.Segmenting grouting refers to dividing the range of grouting into several sections of equal length grouting body, and the grouting amount per unit length of each section is determined according to the stratum displacement of the position of the grouting body. Multi-point grouting refers to the fact that the length of several independent grouting bodies is very small, and only concentrated grouting is carried out at the depth of the station floor. The amount of grouting of each grouting body is determined according to the displacement of the stratum. By comparing the stress of station structure under different grouting conditions when the same station deformation control target is achieved, the best grouting scheme is selected.

At present, the foundation pit construction is developing towards the trend of “deep and large”, the excavation range is large, and precipitation measures are usually required, and the impact of foundation pit excavation on adjacent buildings(structures) has attracted increasing attention. The impact of large-scale foundation pit group excavation on the existing urban rail transit interval tunnels and the safety risk control technology are studied through literature research and numerical simulation. Firstly, the deformation characteristics and influencing factors of large-scale foundation pit group excavation are analyzed, and the relevant cases and experiences in the existing literature are summarized. Secondly, the possible safety risks of foundation pit excavation are discussed, the deformation of foundation pit excavation on the existing urban rail transit section tunnel is calculated through numerical simulation, and the risk control technology and measures in the form of underground diaphragm wall + internal support support structure are proposed to meet the requirements of the specification. The result show that the excavation of foundation pit group has a certain impact on the existing urban rail transit section tunnels, but the potential risks can be reduced and the safety of the tunnel structure can be guaranteed through reasonable safety risk control technology. The result of the study provide a reference for the safety design and construction of the project to be built.

The deformation characteristics and shear strength of slope soil is an important basis for slope stability analysis. In order to study the deformation characteristics and shear strength of laterite clay slope under rainfall, the actual red clay slope engineering is taken as an example, considering the influence of rainfall on the deformation and shear strength of the slope soil, and the creep characteristics of the red clay slope are obtained through the lateral deformation monitoring of the typical borehole of the slope.Field shear tests on three groups of pre-slope samples and three groups of slope samples of the laterite clay slope are conducted. The results show that during the monitoring period, the lateral deformation of the red clay slope at the same borehole depth gradually increases with the infiltration of rainfall, and the lateral deformation of the same borehole soil layer decreases with the increase of borehole depth. The shear stress-shear displacement relationship curve of slope soil develops and changes according to the four stages of "elastic deformation, yield deformation, hardening deformation and failure deformation" has significant stress-strain softening characteristics, and there are obvious peak strength and stable residual strength. The empirical model of the peak and residual strength of the pre-slope specimen has been provided and the slope specimen and the empirical shear strength index of the pre-slope soil body are given as c_f=38.760 kPa、φ_f=15.9°、c_fr=34.577 kPa、φ_fr=12.6°, and the empirical values of shear strength index of soil body of slope body c_f=33.522 kPa、φ_f=10.2°, and c_fr=30.234 kPa、φ_fr=9.5°. The research result can provide theoretical and data reference for the stability analysis of red clay slopes, determination of shear strength parameters and similar engineering construction.

The application of 3D geological modeling technology in geotechnical engineering investigation is mostly limited to the "visualization" stage, making it difficult to fully utilize the advantages of 3D geological models. To address issues such as the difficulty of cross-platform sharing of drilling data and insufficient precision of 3D geological attribute models, based on the Phase II project of a reclaimed water plant in Beijing, the open environment of EngeoCAD survey software is used to develop drilling data interface. Based on drilling data and test data, the 3D geological structure model and high-precision attribute model of geological body are constructed, and the application of the model is verified by geological profile comparison and light cone dynamic penetration test. The results show that: The developed data interface could quickly implement the automatic import of geological drilling data from the Beijing engineering investigation cloud platform to 2D survey software, and then to professional 3D geological modeling software. Through profile comparison and analysis, the 3D geological profile shows a high degree of spatial extension consistency with the traditional 2D geological profile strata, with only slight inconsistencies in some lens bodies and thin interlayer termination points. Field measurement validation shows that the relative error in the fill volume calculated by the 3D geological model and the traditional method is 3.85% and 9.84%, respectively, demonstrating a clear advantage in the calculation accuracy of the 3D geological model. Through actual excavation layer verification, the spatial distribution domain of poor strata identified by the attribute model matches the actual strata with high accuracy. The developed data interface has bridged the gap for cross-platform sharing of drilling data in the ‘Cloud Era'. The attribute model integrates physical and mechanical parameters of geotechnical bodies into geological modeling, effectively supporting the engineering geological evaluation of site zoning and segmentation.

Landslides, as a common geological hazard, pose significant threats to human life, property safety, and operational stability of engineering facilities. Multi-source heterogeneous monitoring technology, which integrates monitoring method of diverse principles and data formats—including multi-temporal optical satellite remote sensing images, Interferometric Synthetic Aperture Radar(InSAR), unmanned aerial vehicle(UAV) aerial survey data, and the Global Navigation Satellite System(GNSS)—is recognized as a novel approach for landslide deformation monitoring. This study was conducted on the Hongxiang landslide along the right bank of the Dadu River in Hanyuan County, Sichuan Province, to systematically evaluate the application efficacy of multi-source heterogeneous monitoring technology. The result are summarized as follows:(1) Deformation zones and tensile cracks were clearly identified through the synergistic use of multi-temporal optical satellite imagery and UAV aerial data. The most intensive deformation area was localized in the middle-front section of the landslide, where maximum settlement cracks were measured at 10 m in length and approximately 5 cm in width.(2) Quantitative deformation values were derived from InSAR monitoring, revealing a maximum displacement of 143.2 mm at the frontal margin, 55.5 mm deformation at the rear edge, and intermediate deformation ranging between 65-120 mm in the central section.(3) Ground-based GNSS measurements were implemented to record displacement values at four monitoring points: 127.99 mm, 115.18 mm, 133.55 mm, and 72.47 mm. These field-measured values are proposed as critical quantifiable indicators for landslide early warning systems. The findings demonstrate that multi-source heterogeneous monitoring technology can be effectively utilized to enhance the accuracy and reliability of landslide deformation monitoring. This integrated approach is validated to provide scientifically robust and comprehensive data support for landslide hazard early warning and mitigation decision-making, highlighting its significant application potential.

Geological disasters occur frequently in the loess distribution area of the Yellow River basin. Only during the "7·20" extremely heavy rainstorm in Zhengzhou, hundreds of geological disasters occurred in the loess distribution area of the Yellow River basin in western Henan, resulting in significant losses of personnel and property. Carrying out vulnerability assessment research is the key to prevent and control geological disasters of loess. 13 evaluation factors are selectd including slope, landform, distance from structure, distance from water system, land use type, and distance from buildings. Based on information, I, BP neural network, and particle swarm optimization(PSO), I model, I-BP model, and I-PSO-BP model are constructed to evaluate the vulnerability of geological disasters in Kangdian Town, Gongyi City, which suffered the most serious geological disasters during the "7·20" extremely heavy rainstorm in Zhengzhou on the south bank of the Yellow River basin. Compare and analyze the accuracy, predictive ability, and rationality of different models using AUC values, frequency ratios, and field validation. The result show that the accuracy of the three coupled models(I-PSO-BP) is higher than that of other models(I and I-BP). The AUC values of the three models are 0.968 3, 0.976 4, and 0.978 6, respectively, and the accuracy rates are 59.14%, 92.00%, and 92.60%, respectively. The single model has the lowest accuracy. I-PSO-BP has higher accuracy and stronger prediction ability, which is most consistent with the field verification practice. The proportion of high, medium, low, and extremely low prone areas in the I-PSO-BP model is 5.09%, 2.25%, 7.52%, and 85.15%, respectively. The medium and high prone areas are concentrated along the gullies where human engineering activities are frequent, and human engineering activities such as slope cutting are important factors in the occurrence of geological disasters in Kangdian Town.