Design And Analysis For Shaking Table Test Of Subway Mold Station In Loess Sites

With the improvement of urbanization level in China, the congestion of urban traffic is growing simultaneously. To alleviate the situation, the planning and construction of subway on a large scale gains much attention in most of the first- and second-tier cities in our country. As one of them, there are more than 10 subway lines planned for Xi’an. Most subway stations in Xi’an, however, are constructed in loess sites and 8 degree fortification zone, thus it will bring much inconvenience to the production and living of the whole city once the subway station structure encounters earthquake damage. The existing earthquake damage shows that the subway station is not only difficult to repair, but also cost a lot. Therefore, it is of great significance to conduct and analyze the shaking table test of subway station in loess sites for further seismic design and study. This paper develops the shaking table test scheme design of subway station in loess sites, and validates its rationality. The main research work includes the following aspects:(1)The advantages and disadvantages of various shaking table test method are summarized firstly through consulting a great number of research literature about underground structure shaking table test. In view of the test content, the shaking table, shear model box and various test components are selected to satisfy the test requirements.(2)Shaking table test scheme suitable to the typical loess sites of Xi’an is designed. The main design and research content includes the following aspects: the similarity ratio of each parameter in the whole test is designed by determining the length, material, and density similarity ratio; reinforcement scheme fit with this test is determined after comparing the advantages and disadvantages of two conventional reinforcement schemes of similar bearing capacity and equal area reinforcement ratio; the station model is manufactured using micro-mold; the design and layout of the counterweight is performed using under-artificial quality model; natural seismic wave and synthesis seismic appropriate to the loess sites of Xi’an is compared and selected; sensor placement optimization research of seismic response is performed.(3)Finite element software ABAQUS is used to simulate the mechanical characteristic of the test model under the action of 8 degrees fortification earthquake. The response displacement method introduced by Code for seismic design of urban rail transit structures(GB 50909-2014) is adopted。In order to restore the real test conditions, three dimensional solid elements are adopted in analysis model rather than the beam element analytical model recommended by the code. The simulated results are compared with the test results under the condition of acceleration 0.2g of Xi’an artificial wave. The damage characteristics of subway station structure in the test and in the practical engineering are also compared. The rationality and feasibility of the test scheme is validated from the above two aspects.