High speed railway is a complicated and enormous system. Beijing-Tianjin inter-city railway is the first high speed railway that has started commercial operation in China. There are significant innovations made on key technologies and four challenging issues including system design and integration, high track regularity and stability, high safety and riding comfort, reliable operational control and high efficiency. China Railways experienced three years to build Beijing-Tianjin inter-city railway. The operational performances of Beijing-Tianjin inter-city railway showed that the whole technology is ranking at the leading position in the world. The technologies are convincing exemplary demonstration and will be applied to build the high speed railway network in the future.
The steel truss structure is adopted for all of these bridges of the under construction Beijng-Shanghai and Beijing-Guangzhou High Speed Railways across Yangtze River and Yellow River, and they are multy railway lines or rail-cum-road bridges, with heavy loading capacity and high railway operation speeds. Some new materials, new structures and new workmanship are applied accordingly.
According to the features of bridges in the section between Beijing and Cangzhou in Beijing-Shanghai high-speed railway, the construction and technical innovations which include special representative structure of bridges, control measures on settlement after the completion of bridges in the regional land subsidence area and assurance methods on high track regularity of ballastless track in 350 km/h speed are mainly introduced.
Based on engineering practice in Beijing-Shanghai high speed railway, effect to concrete workability, meachincal performance, and durability of mineral admixtures are studied, at the same time the preparing technology of high performance concrete with high-volume supplemementary cementitious materials are studied. Combining with pracitce engineering, control technology of raw materials, design of mixing proporation and construction for high performance concrete with high-volume supplemementary cementitious materials are introduced.
Beijing-Tianjin inter-city railway is the first built passenger dedicated line with the speed of 350 km/h in our country. During the design, new ideas of bridge construction were carried out in order to ensure the safety, amenity and stability requirements of the train under high-speed condition. At the same time, concepts of environmental adaptability, serving for transportation and comprehensive benefits were followed. In the whole line of the railway, long-bridge scheme was adopted, and the most advanced technology of unballasted track was utilized in bridges which account for 87.7 % of the total line. The success of the design and construction of bridges in Beijing-Tianjin inter-city railway accumulated valuable experiences for large-scale construction of high-speed railway at the future. And roles of demonstration, landmark and prototype are played at the same time.
Specific requirements and methods of settlement monitoring which are used in bridge of unballasted track passenger dedicated line or high-speed railway are introduced systematically, and mathematical model and determinant conditions of settlement are proposed simultaneously, taking Beijing-Tianjin inter-city railway as an example.
The criterion for residual deformation of Substructure of unballasted track on railway passenger dedicated line is extremely strict in order to satisfy the safety and comfort requirements of the high-speed train. Based on new Wuhan(Guangzhou railway passenger dedicated line engineering practice,this paper introuduces the key technologies for the deformation monitoring, data management and analysis system, the prediction method and assessment criterion are put forward to determine the reasonable time of unballasted track laying to guarantee the quality of unballasted track. Some advice provide reference for the ongoing unballasted track on railway passenger dedicated line construction.
As a case for study, the online montoring and numerical analysis for 32 m concrete prestressed box girder prestressing and elastic camber effect in Wuhan-Guangzhou passenger express line was performed in the paper. The effect of monitoring and analysis, based on the engineering practice, the control measures of the box girder creep camber were put forward, which can be taken as a reference and experience guidance for the similar projects.
On the basis of the research results of the project, the Research on the Industrialization of Freely Supported Box and Girder for Passenger Express Line, in Ministry of Railways and China Railway Construction Corporation, and the programming and design experience for almost 30 girder prefabrication fields, the three important aspects of girder field construction, i.e. site election, plane layout and corollary equipment, are discussed in depth.
Polycarboxylates water-reducing admixture possesses the capability which could meat with the comprehensive performance of high performance concrete using in field of passenger dedicated line. Problems of engineering application of polycarboxylates water-reducing admixtures were analyzed. At present the key for polycarboxylates application is to settle the compatibility with cement andkeep the quality retention of this admixtures.
Take Sutong Bridge as the subject investigated, the correctness of the geometry control theory is verified by the numerical simulation analysis. The influences of structural geometric shape induced by temporary loads and temperature field during the construction procedure are investigated. Taking the impact of geometry non-linear during construction into account, the simulation results indicate that only the stage state of the structure during construction is affected and the completion stage state is not affected. Geometry control theory applied to control the super-span cable-stayed bridge construction, and satisfied outcome of construction control can be achieved based on geometry control theory.
Urban rail transit construction in our country is now stepping into a quickly developing period. Based upon urban rail transit planning of Beijing, this article analyzes questions existing in urban rail transit planning, construction and management. Using international metropolis's urban rail transit planning, construction and management experience for reference, the article brings forward optimized countermeasures on building synthesized harmonizing mechanism, perfecting urban rail transit planning and creating synthesized communication hinges, as well as giving concrete suggestions on urban rail transit's transfer and joint by utilizing state railway resources.