Research On The Seismic Responses Of Subway Station Based On Shaking Table Tests

In recent years, the subway construction of our country is in the ascendant, while the seismic research on underground structures is lagging behind, and the seismic analysis method is not perfect without independent seismic design criterion of underground structures. Once the subway is destroyed, it will result in severe direct economic losses and secondary disasters which are hard to repair. Therefore, it is essential to study the seismic response of structures beneath the ground. Furthermore, numerous studies demonstrate that the non-uniform of ground space has a relatively high influence on underground structure which length is more than 100 meters. Based on previous studies, a series of shaking table tests were designed and conducted on scaled subway station model with silty clay foundation under non-uniform input earthquake wave excitation. After obtaining the regularity of its dynamic responses, numerical simulation was conducted to verify the results’accuracy, thus offering advices for the aseismic design of subway station. The main tasks and conclusions are listed below:(1) The Zexu Square station of Fuzhou metro line No.1 is chosen as the case-study background. According to the dynamic similarity theory, the design of subway station model’s shaking table tests were proposed. The test model is scaled to 1/30 of the case-study double-deck subway station, which real length is 135m. After the analysis of material ratio and design of steel reinforcement, micro-concrete and galvanized steel wire were used to build the test model. Based on the existing experimental conditions, two rigid soil boxes and a subway station model were built, and polystyrene foam plates with certain thickness were set in the inner lining of steel box to alleviate wave reflection effect.(2) In accordance with the local ground condition, El-Centro wave, Kobe wave, Chi-Chi wave were chosen as the input waves to implement the shaking table tests of subway station model under non-uniform input earthquake wave excitation. The results showed that subway station’s seismic responses of one end which waves arrived earlier were larger than that of the later one. The peak value of seismic wave is adjusted according to the actual load capacity of the shaking table, and the operating modes could be settled. The non-uniform input earthquake wave excitation was provided by ServoTEST shaking table system in Fuzhou University from the aspect of traveling wave effect, in other words, there is a time-delay of input waves between the two tables.(3) After the experiment, the test results were analyzed considering the variation of parameters ranging from acceleration, to soil pressure, to component strain, etc. Herein, the differences of sections’dynamic responses when seismic waves arrive at different times, the differences of each component’s dynamic responses in the same section, and the differences between the station and soil’s dynamic responses could be obtained, thus the regularity of the station’s dynamic responses could be deduced.(4) The numerical analysis software ABAQUS was used to build its 3-D model and implement numerical simulation considering the dynamic response of structure-soil interaction. The experiment results were compared with the numerical results. The results demonstrate that, the regularities drawn from shaking tests and numerical simulation are basically consistent with certain deviations.