Research On The Influence Of Presence Of Adjacent Utility Tunnel On Seismic Response Of Tunnel Structure

Subway tunnels and utility tunnels are important parts of urban underground space engineering.It can be seen from the historical data of earthquake disasters that once the underground structure is damaged by the earthquake,it will not only cause loss of life and property but also be difficult to put into use again.In recent years,subway tunnel and utility tunnel have been built together.Many cities have built to be a ‘sponge city' with subway tunnel construction.Therefore,within the development of underground space engineering,utility tunnels and subway tunnels may inevitably appear the space form of parallel or cross vertical.At present,there is little research on the influence of presence of adjacent utility tunnel on seismic response of tunnel structure.Therefore,this paper relies on the utility tunnels second phase of the Jiangbei new district in Nanjing to establish three-dimensional refined finite element model of utility tunnel structure-soil-subway tunnel structure based on ABAQUS finite element software with the modified Davidenkov model and viscous-spring artificial boundary.Then the seismic response analysis is carried out,which mainly includes the following work:(1)Based on the Japanese KIK-net seismic network record and the Matlab software GUI development platform,the SELECTWAVE software with seismic wave screening and processing was compiled.According to the seismic environment of Nanjing near field and historical seismic activity records,the suitable seismic wave for Nanjing site was selected: Shizuoka wave and Tochigi wave.(2)Comparing the dynamic response of utility tunnel to existing adjacent tunnel structure under different locations,it is found that the existence of the utility tunnel can suppress the seismic response of the subway tunnel.From the perspective of the optimal seismic performance of the tunnel,the utility tunnel or other underground structure in security level can be placed under the tunnel.(3)The seismic response of the utility tunnel-soil-subway tunnel is analyzed under different ground motion intensity and different spectral characteristics.It is investigated that the seismic response of bottom of subway tunnel is greater than the rest under the excitation of the near-field wave,because the high-frequency is filtered by soil medium.However,The seismic response of top of subway tunnel is greater than the rest under the excitation of the far field wave which seismic intensity is same as near-field wave.The seismic response of the subway tunnel increases nonlinearly with the increase of seismic intensity under the same seismic frequency.