Seismic Response Analysis Of Soil-Subway Tunnel Group Interaction System

In recent years,the construction of subway tunnel is in full swing with the rapid development of Chinese economy and science and technology.For the need of transfer,some sections require multiple lines parallel,which put forward higher requirements for seismic performance of the structure.The subway tunnel in China seismic response research started late and develops rapidly.Dynamic response study has made some achievements in the single tunnel and double tunnel group,but the seismic performance of the tunnel group is relatively small.Therefore,it is of great significance to study the dynamic response law of four hole parallel subway tunnel group.Based on the project of Tianjin metro line five and line six,a 3D finite element model of four hole parallel which based on ABAQUS finite element calculation software tunnel is established.The use of Python language program and the boundary of seismic waves is developed,The response of tunnel group structure under the influence of various factors are explored,and a reference for the future design of subway tunnel is provide.The main research contents and achievements are as follows:(1)The principle of seismic waves with viscoelastic boundary and viscoelastic boundary conditions are study.The visco elastic boundary wave and the precision is applied automatically by using the Python programming language,which lays a foundation for further study on the underground structure and the visco elastic boundary wave and applied results are verified at the same time.The calculation results show that the accuracy of the method meets the requirements,and the seismic analysis of underground structures can be carried out.(2)The finite element of containing free field,double tunnel field,four tunnel field models are established.The spectral characteristics of different seismic input model under the condition of acceleration,displacement and hoop stress are analyzed.The results show that the existence of the four-hole tunnels will make the filtering more obvious,but it can reduce the amplification of acceleration along the depth direction of seismic wave;the lower tunnel increases the relative displacement of tunnel group overall response,but it also has a certain damping effect on the upper tunnel;tunnel under earthquake the lower tunnel group damage is more serious,the upper tunnel affected by the earthquake.(3)The frequency spectrum characteristics,acceleration peak value,displacement response and circumferential stress variation law of the soil tunnel group are analyzed by changing the horizontal spacing and vertical spacing of the four hole tunnel group.The results show that isolation of the upper lower tunnel tunnel is obvious when the horizontal distance is near.The isolation effect gradually weakened with the increasing of distance,but the vertical spacing on the lower tunnel is close to the seismic unfavorable.