Experimental Study On SElsmic Behavior Of Large Span Metro Station Without Columns

Osaka-Kobe Earthquake in Japan caused serious damage to Kobe Dakai Station,forcing domestic and forELgn scholars to begin to study the sELsmic performance of underground structures.Among them,long span subway station without columns has the advantages of beauty,convenience,practicality and relatively low cost.however,there is very little research and application in engineering on the subway structure forms without columns at home and abroad.Therefore,it is of a great practical significance to study the sELsmic performance of such structure.Supported by the background of the Nanning metro project,in this paper,the large span metro station without columns was taken as the basic structure form to carry out experimental and numerical simulation research,which taking the Nanning Rail Transit Line 5of the Nahong to Jinqiao station as the research object,the details are as follows:(1)A small vibrating table test plan was designed for the subway station without column.Based on similarity ratio theory,the similarity ratio parameters of model under 1/80 ratio were calculated.The artificial remolded soil、model box and station structure materials accord with the small shaking table test were selected and material performance tests were carried out too.Besides,according to layout of the acceleration points and the selected sELsmic waves,the final test conditions and loading sequence were determined.(2)The dates of shaking table test were collated and analyzed.First,the boundary effect of the test is judged by dates.Secondly,the detailed structural-soil dynamic and frequency domain analysis were carried out for three test conditions,which were comparison of different covering hELght、comparison of different site types and comparison of different width of soil beside the structure.The dynamic response of soil-structure system under different conditions were summarized,which could provide reliable data for the shaking table test of the this structure forms.(3)The dynamic elastic time history analysis of three test cases was carried out by the finite element software of ABAQUS.Also,numerical results of sELsmic damage cloud、 acceleration and horizontal displacement peak values were compared with the test results to verify the feasibility and reliability of the test data.(4)The external wave source vibration in two-dimensional space was simulated by ABAQUS among the four different artificial boundaries of underground structures which are common to see.At the same time,the calculation process of equivalent force of two dimensional S and P wave were derived.Finally,an example of plane incident S-wave was given to verify the validity of wave equivalent input and the accuracy of consistent viscousspring artificial boundaries.(5)A two dimensional plane structure model of a large-span metro station without column was established.Constitutive relation of different materials was explained and calculated in detail and the damage cloud、internal force distribution and sELsmic response in different regions of the structure were acquired by numerical simulation.Finally,dynamic responses and sELsmic weak region of this kind of structure form under the coupling of multi-factors of earthquake and soil-structure interaction are analyzed.