Study On Seismic Performance Of Subway Station In Ground Fissure Site

As a special engineering geological disaster,ground fissures destroy the integrity of the site and aggravate the seismic response of the structure.In recent years,a large number of built and planned subway stations in Xi’an have been affected by ground fissures,and some have even directly crossed existing or secondary ground fissures.Therefore,it was of great theoretical significance and practical engineering value to carry out analysis and research on seismic performance of underground structures under high-intensity ground fissures.In this paper,the subway station of the ground fissure site was taken as the research object,and the seismic performance of the underground structure was analyzed by a combination of experimental research and numerical simulation.First,the design completed the shaking table test of the subway station at the ground fissure site.The dynamic characteristics of the test model structure and site soil are studied,and the response law of peak acceleration of input seismic wave to the peak acceleration of each layer of underground structure was analyzed,analyzed the seismic response law of ground fissure site.Secondly,based on the ABAQUS large-scale nonlinear finite element analysis platform,the numerical model of the dynamic interaction between the ground fissure site soil and the subway station was established,and the time history analysis of the ground fissure site soil-underground structure finite element model was carried out.Comparing the test results,the two showed good consistency.At the same time,through the comparative analysis of the soil-underground structure finite element model of the ground fissure site and the ordinary site,the influence law of the ground fissure site on the underground structure was discussed.Finally,using Pushover analysis method,the whole process of the subway station structure damage and destruction was analyzed.By comparing the time history analysis and Pushover analysis,the results of the two analysis methods were close.At the same time,the underground structures with different site conditions and different burial depths were discussed,and the weak parts of the underground structures in the seismic design were found.Strengthening measures were proposed to strengthen the connection of weak locations,especially the bottom of the center column,to ensure that its bending loadbearing capacity meets the design requirements.