Shaking Table Test Research On Seismic Response Of Tunnel-Soil-above Ground Structure Interaction System

With the further development of urban rail transit construction in China,the projects of adjacent construction appear constantly.Such as the shield tunnel of ultra-close multi-hole overlapping shield through each other,shield tunnel close through the surface of buildings and so on.Under the background of the rapid development of underground space in the city,the interaction between the underground structure and the surface structure may not be neglected in the case where the distance between the underground structure and the surface structure is getting closer.They constitute a complex dynamic interaction system.However,on the one hand,due to the early development of the underground structure scale and size are relatively small,on the other hand,the history of underground space exploitation on a large scale in China is only more than ten years,the effect of this interaction has not been reflected,so the dynamic interaction has not caused enough attention,so that there are not enough researches about the dynamic interaction.Considering shortcomings above,first,this paper reviewed the current research status of shaking table model tests on soil-structure interaction system,in order to conducting the shaking table test of complex system which is about tunnel-soil-frame structure as reference.Then,conclude and tidy the soil-structure interaction system shaking table model test scheme design of the key problems encountered.Based on the above research results,the shaking table test of complex system which is about tunnel-soil-frame structure is completed.Firstly,the tests include four types,which are free-field,tunnel-soil,soil-frame structure and tunnel-soil-frame structure shaking table model tests;Secondly,the geometry similarity is set to 1/20 according to the selected prototype structures and experiment conditions,and at the same time,gravity undistorted model was employed because both underground structure and aboveground structure are included in the model test,weights were determined for underground and aboveground structures by the similarities;Lastly,sawdust soil was selected to model clay to reduce system total weight,and dynamic tests were conducted to obtain its dynamic properties and computation parameters.Based on the result of free-field,tunnel-soil,soil-frame structure and tunnel-soil-frame structure shaking table model tests,this paper mainly analyzes the measured values of the acceleration response of the model system and distinguishs the system natural frequency and damping ratio,as well as analyzes the boundary effect of the model box.Through the comparative research between different operating conditions which is the change law of acceleration response,it is concluded effects of underground structure and surface structure on free-field ground,as well as effects of underground structure on surface structure ? surface structure on underground structure.The research results showed that the shaking table test reaches the expected target before the experiment,the research results of the project would provide references to improvement of structure seismic analysis theory and city holistic planning in China.