Based on the background of high-precision concrete construction in Three Gorges Project ship lift, the meaning of hydraulic high-precision concrete and its construction techniques and construction practices are expounded in this paper. The main accuracy control standards, high-precision measurement technology, high-precision concrete construction technology and concrete physical test results of the high-precision concrete construction of the Three Gorges Project ship lift are introduced in details.
The ship lift of Three Gorges Project is huge and technically complex, and as there is no similar ship lift in the world as a precedent putting into operation, it has been well concerned by domestic and international engineering and technical community. The design and research process of Three Gorges Project ship lift , has been strongly supported by many domestic scientific research and design units, their works provide a theoretical basis for the gradual improvement of the ship lift design. After scheme comparison, the Three Gorges Project ship lift eventually identified as rack and pinion climbing type, its equipment is of complex structure and its manufacture, installation and civil structure need high construction precision requirements, and the Sino-German joint design approach is adopted for the first time. The final review and acceptance for the design results of every stages are executed by Quality Experts Group of Three Gorges Project organized by the Three Gorges Project Corporation. For the technical difficulties and key technical issues of the ship lift, a series of special experimental researchs, such as "research on manufacturing technology of rack, nut column" are organized to examine the rationality and implement ability of the key project design of ship lift .To reduce the effect of tower column deformation on the installation accuracy of rack and nut column, some research and adjustment are done to the construction procedures of ship lift to ensure safe and reliable operation of ship lift. Engineering construction proofs that the management, technical measures undertaken in this paper are scientific and they ensure the smooth implementation of the construction of the Three Gorges Project ship lift.
This paper firstly describes the whole construction program of the tower column. Then the important and difficult construction problems have been analyzed, such as the precision control of civil structure, the precision control of metal structures and its embedded parts, concrete temperature control and crack prevention, and safety control. At the same time, the construction surveying control technique, the temperature control and crack prevention technique of thin wall concrete, high precision concrete continuous and rapid construction technique,metal structure construction technique,and the construction technique of high altitude and large span beam structure have been made a systemic summary. The application of those construction techniques meets the requirement of high precision construction of the tower column and ensures its smooth construction. Meanwhile, these construction techniques lay a solid foundation for the construction of similar projects.
The construction time limits for the tower column concrete of Three Gorges Project ship lift is pressed for time and require high accuracy. In order to ensure the construction progress and quality, the hydraulic self-climbing formwork is used. This paper focuses on the construction technology of hydraulic self-climbing formwork, improvement measures of self-climbing formwork as well as structural measures made in the plate girders and corbels department of tower to meet the rising-up of self-climbing formwork on Three Gorges Project ship lift tower column concrete. It has been found that application and improvement of the hydraulic self-climbing formwork construction technology meet the design requirements of the tower column cylinder concrete of the Three Gorges ship lift, effectively improve the construction efficiency, save cost, ensure the engineering quality and improve the safety of the construction,can provide reference for other hydropower project construction.
he concrete construction of the beam concrete of tower load-bearing structure in Three Gorges Project ship lift is difficult, with high-complexity and no mature technology available for reference. In this paper, combined with the structural features and construction characteristics of concrete pouring in tower beam of the Three Gorges Project ship lift, the concrete construction technology for continued construction of the Three Gorges Project ship lift top beam is summarized, which uses hierarchical, block pouring approaches. Through scientific computing, reasonable construction machinery layout and construction management are made out to ensure the quality of concrete construction for tower beam. The monitoring results analysis on Bailey shelf support system indicate that, the stress deformation, deflection and bent deformation of Bailey shelf support system meet the construction load requirements. The cylinder displacement also meet the technical requirements, thus Bailey shelf support system is stable and secure. The concrete construction practices of Three Gorges Project ship lift tower beam certify the effectiveness and reliability of the technical solutions. And it also provides a reference for the construction organization design and on-site implementation of similar projects.
According to the use of the steel roof truss on top of the Three Gorges Project ship lift machine room, steel roof truss structure is analyzed. The safety of steel roof structure and its design scheme is verified by using the establishment of three-dimensional finite element model. At the same time, based on the research of the steel roof truss construction scheme, construction procedure and construction equipment selection are formulated which is suitable for Three Gorges Project ship lift steel roof construction work at the top of the room environment. Specific construction methods have been proposed for steel truss segment, setting of lattice racks, steel truss hoisting installed central control room, roof rack, roof panel, etc. The structure design method and construction scheme of the steel roof of Three Gorges Project ship lift the top room truss ensure the smooth installation of the steel roof truss and safe operation. It has a certain reference value to similar projects
Aiming at the impact of load imposed order of balance weight and ship compartments on the the deformation of pillar and built-in structure parts, the construction order of ship compartments chamber and equipment installation sequence scheme are studied, which Solved the technical problems that the impact of load imposed order of balance weight and ship compartments on the the deformation of nut column, rack ,and vertical direction displacement. According to the simulation results of pillar structure, the impact of the ship chamber and balance weight loading sequence to the nut, rack and vertical guide displacement in the direction across the river, along the river and vertical is analyzed. Reasonable ship lift ship compartments chamber construction procedure and construction schedule arrangement are set by optimizing the construction procedures. The construction procedures can make nut, rack, vertical direction, the structure of the ship compartments and pillar under various operating conditions on the displacement meet the safety requirements. And the procedures based on the construction progress of the construction can meet the requirements of ship lift commissioning. Engineering practice proved that chamber construction procedures of Three Gorges Project lift ship established in this paper are reasonable and scientific which ensure the smooth construction of ship chamber of Three Gorges Project lift ship and guarantee the safe operation of ship lift. these construction procedures can provide a reference for similiar project.
In order to choose the suitable grouting material and grouting process, and simulate the actual situation of clearance grouting of rack and nut column in ship lift, grouting process test and prototype grouting experiment were carried out respectively. Comparing three kinds of domestic grouting material and the German PAGEL grouting material in grouting process test, the experimental results showed that the physical and mechanical property indexes of German PAGEL grouting material were superior to the domestic grouting material. In prototype grouting test, selection of the grouting equipment type, mixing time, templates seal, method of grouting parameters control of grouting flow were researched, and some applicable grouting material and grouting process were selected which were suitable for the rack and nut column joint in Three Gorges Project ship lift. The above test effects were obvious, and solved the construction problems of great difficulty in grouting seal and easy blockage of pipeline, etc.
During the continued construction of Three Gorges Project ship lift, the loading test experiment has been carried out before the pouring work of the beam concrete, which is aimed at the complex characteristics of the bracing system of tower column beam construction. The experiment chose axle 1 beam, axle 2 beam and corresponding foundation beams' Bailey trusses as models, and the loading prototype test is conducted according to 1:1 ratio scale. Through arranging proper monitoring points and adopting reasonable testing frequency, the experiment completed the collection and analyzing of test data. The test results are as follows： The test obtaines the maximum stress of different member bars during the loading procedure. With the increasing of loading capacity, the bending variation of beams and Bailey trusses build up slowly, while altitudes of formwork and framed bent drop. With the increasing of loading capacity, the beams and foundation Bailey trusses experienced subtle side movements. The variation of both the axle 2 beam formwork and the framed bent's verticality from left to right is very tiny. The monitoring data indicates that, the parameters of strengthened Bailey trusses meet the safety requirements, and the proposal applies to the tower column beam construction while ensuring its safety.
The structure of ship lift tower in Three Gorges Project, belonging to high-rise and thin-walled structure, is complex. And its concrete temperature is greatly influenced by the ambient temperature. Thus, the concrete temperature control of it is extremely difficult. In construction practice, by optimizing the concrete mix, rationally arranging the concrete cooling system, scientifically regulating the temperature and time of cooling water, scientifically adjusting the external ambient temperature, introducing new materials and new processes of concrete curing and strengthening the construction management measures of temperature control and other measures at the same time, the construction quality of concrete tower is ensured and the scientific rationality of the temperature control program is proved. Temperature control and crack prevention technology for concrete in ship lift tower of Three Gorges Project has important reference value to research the technical level of temperature control measures for ship lift projects at home and abroad, to improve the quality of concrete construction in hydropower projects and to save the cost.
This paper describes the selection process on concrete construction equipment of ship lift boat cab segment in Three Gorges Project in detail, including analysis on the characteristics of concrete construction in boat cab segment, selection argumentation of construction equipment at the tender stage and system adjustment and optimization of equipment selection at the construction stage. The engineering practice effect of construction equipment indicates that the concrete pouring equipment layout plan for Three Gorges Project ship lift boat cab section effectively covers all pouring surface, meeting the warehousing strength requirements in concrete pouring peak, and the construction schedule, cost, safety, can be effectively controlled. The concreting equipments of Three Gorges Project ship lift boat cab segment have been pre-rational planned, post-system adjusted and optimizated , they play an important role in the successful end of construction of Three Gorges ship lift project, and they have high promotion and application value.
This paper describes the embodiment of concrete construction supporting system of the Three Gorges Project ship lift tower beams. It begins with the load requirements, structural strength requirements, and deformation stability requirements of the Bailey rack supporting system. Through scientific computing, reasonable bearing system design, structural design and the upper steel pipe bent design of Bailey rack supporting system are developed. And the monitoring of the stress and strain, deformation, displacement are done to the Bailey rack supporting system and the corresponding tower concrete wall structure around the concrete pouring process. The monitoring results show that the beam supporting system meets the pouring and supporting requirements of beams. The construction quality is first-rate, safety and reliable. Both the design and the construction are feasible.
The installation technology of counterweight system of Three Gorges Project ship lift has been studied in this paper based on the construction requirements of counterweight system and construction environment. The overall installation procedure of counterweight system has been put forward which are suitable for Three Gorges Project. Then the construction processes and construction methods of balance chain guide installation, balancing pulley installation, main hoist rope installation and counterweight installation have been described in detail. At the same time, the installation technology system of counterweight system is set up. This construction technology effectively solves many problems faced in the installation process of counterweight system of Three Gorges Project ship lift, such as large scale project, large component size, high accuracy requirements, high installation elevation, difficult construction, construction with wide distribution, complex construction conditions, etc. Meanwhile, the technology provides a good reference for similar projects at home and abroad.
The installation and demolition of Bailey truss support system of Three Gorges Project ship lift belongs to be grade separation operation. Because of the narrow construction site, high construction strength, and big construction disturbance, the installation and demolition of Bailey truss has been one of the construction problems of Three Gorges Project. The installation and demolition technology system of bailey truss support system has been established based on the analysis of construction environment and the characteristics and requirements of different parts. The technology system contains the layout of construction equipment, the division of lifting units, the set of lifting point, and demolition plans of different parts and so on. This technology system ensures the smooth implementation of the installation and demolition of bailey truss. Construction schedule, cost, and safety of this project have achieved good results, and this technology system can provide a reference for similar project.
The overall construction program has been changed in the extension project of Three Gorges Project ship lift. Because of it, the tower column, rack, nut post, counterweight, and longitudinal guide rail should be constructed at the same time which forms the grade separation operation. In this case, conventional shelving scheme can not meet the requirement of construction. So the aerial comprehensive lifting platform is adopted which can quickly change the vertical construction site and meet the requirements of different parts and working procedures. This platform contains hoist lifting platform, gear-rack lifting platform, and hanging lifting platform. Comprehensive lifting platform can meet the requirements of the installation of metal structure, construction of second stage concrete, installation of mechanical and electrical equipment, concrete pouring of second stage concrete, and pagel grouting. It can relief the intense construction period. This technique after design can be popularized and applied in similar project.
Based on the layout characteristics of the first-stage and second-stage metal structure embedded parts, and combined with the site construction environment, this article analyzes the high precision installation method in detail. At the same time, various construction plans which are suitable for Three Gorges Project ship lift are put forward. These construction plans which have been successfully used in Three Gorges Project have solved many technological problems, such as the deformation control of the embedded parts, fast and accurate positioning, high precision measurement and so on. Meanwhile, these technologies provide a reference for the constructions of similiar projects.
According to technology requirements of installation precision and characteristics of rack, nut column of Three Gorges Project ship lift, and combined with the integrated environment the installation method and installation accuracy control elements have been in detailed analysis, put forward the suitable rack, nut column installation construction process and control measures for Three Gorges Project ship lift. In engineering practice, use the test of datum point to control installation precision of the rack and nut column, put forward the method that screw of finish machining technology to cooperate with jack to readjust as reinforcement measures of installation of the rack, nut column. Thus various high precision standard technical difficulties of installation of the rack, nut column, have been solved, provides the beneficial reference for the similar engineering construction.
Three Gorges Project vertical ship lift is high-walled tower structure. According to the precision requirements of construction for concrete body and built-in embedded parts, the plane, elevation datum transmission and positioning measurement methods for embedded parts in construction survey of concrete and built-in embedded parts of Three Gorges Project ship lift tower were studied. The construction survey technologies, including zenith telescope planar cast point, electromagnetic distance measuring and cylindrical nut type positioning device with a sighting mark in center are applied to size-control measurement for concrete structure and positioning measurement for built-in embedded parts respectively. Through the statistical analysis on the measured data, the construction survey technology solutions for concrete construction of Three Gorges Project ship lift tower are proved to be reliable and feasible.
This paper begins with internal and external factors as well as field operating conditions during the monitoring process. According to the accuracy analysis which is done to several typical monitoring methods and the study which is done to the 360° reflecting prism test, the final choice is that total station polar coordinate would be used as the deformation monitoring method of Three Gorges Project ship lift tower during construction period, and deformation analysis is received using the long-term monitoring data obtained by the use of the method. The results show that tower deformation is greatly affected by temperature; the greater the temperature difference, the greater the deformation. It would be small deformation or even no deformation when temperature difference is small or under constant temperature.
Safety monitoring on crossbeam supporting system of Three Gorges Project ship lift has been introduced in detail through the selection of monitoring objects, determination of monitoring items, arrangement of monitoring points and evaluation on monitoring results. The monitoring items include stress-strain and displacement monitoring of Bailey rack supporting system, deformation monitoring of tower column, verticality and displacement monitoring of bent. By comparing the monitoring results with the data acquired from prototype load tests, it shows that the crossbeam supporting system is very safe and reliable during the construction progress. At the same time, all the monitoring indexes can meet the design requirements. Meanwhile, the safety monitoring plan and technology system can provide a reference for the safety monitoring of other similar projects.