Study Of Pile-Beam-Arch Method And The Reliability Of Lining Structure

With the growing of the economy and the advancement of urbanization construction, the cities in China have developed the urban rail transit to alleviate increasingly serious traffic jams since the 1950s. In the thirteenth five-year plan of China’s economic development, a great period is expected of urban rail transit construction. By 2020, urban rail transit lines will be operating in 50 cities of China. The urban rail transit mileage will reach 6000 km and the number of underground stations will amount in tens of thousands.Most of the subway stations are constructed in commercial areas of the cities. Around a station usually there are many high-rise buildings and underground pipelines. As the evacuation hubs of a city, subway stations are constructed in many different kinds of structure type. Subway stations are constructed in complicated conditions and they are the key control projects in an urban rail transit system. Therefore, research of the underground station design and construction has a very important practical significance. The limit state design based on reliability theory, using the structure failure probability and reliability index to measure the structure reliability, is an effective way to improve the level of engineering design. It is expected to be applied to the design of subway station. The major tasks of this thesis are as follows:(1) Based on previous optimization study in subway station, a numerical model is established by using FLAC software. The optimal process of the excavation in the soil of station hall is obtained by monitoring the sedimentation of the soil in surface layer.(2) A two-dimensional numerical model is built by using Midas software, and a two-dimensional lining structure is analyzed by using the load-structure model and the formation-structure model. The bending moments and internal forces in typical cross section of the lining structure are presented and compared with each other.(3) Based on the response surface method, a series of sample points are simulated to find the relationship between the basic random variables and the lining internal forces. The reinforcement is then designed. Finally, the reliability of the lining structure is calculated based on the response surface method.(4) The partial safety factors for bending moment and axial force are found for the LRFD of lining structure. The two calculated factors can be used as a reference for the corresponding specifications regulated in the future.