Study On Seismic Response And Seismic Isolation Of Urban Utility Tunnel

In recent years,China has made great efforts to develop urban underground space and construct urban utility tunnels.In order to improve the seismic safety and the disaster protection capability of the project,it has a great significance to study the seismic response and seismic isolation of the utility tunnels.In this paper,the finite element method is used to study the dynamic response and seismic isolation of a constructing utility tunnel in China.The research contents are as follows:1)The seismic response of a special-shaped two layers of four storehouse utility tunnel under the action of horizontal earthquake was studied,and the influence factors of materials of structure,buried depth and properties of soil on seismic response of the tunnel were analyzed.The results show that under the horizontal earthquake,the horizontal displacement of the lower part of the utility tunnel is greater than that of the upper part,the shear deformation of the utility tunnel is prominent,and the acceleration of the upper part is slightly larger than that of the lower part,the the main stress at the each node of the partiton wall in the middle of the utility tunnel is littlely large,the change of concrete material has little effect on the seismic response of the structure,but the buried depth of the structure has great effect on its seismic response,with the increase of the buried depth,the peak of the displacement of the structure decreases and the peak of the main stress increases,when the structure is placed on a sandy soil layer,the structural displacement response and main stress response are significantly lower than those of miscellaneous fill and clay layer.2)The shock absorption effects of shock-absorption layers of the utility tunnel were studied,and the shock absorption effects of materials and thickness of the shock-absorption layer were analyzed.The results show that the foam concrete shock-absorption layer outside the utility tunnel can effectively reduce the main stress on the partition wall in the middle of the structure,but the shock-absorption layer has little effect on the displacement response of the structure,the effect of the foam concrete to reduce the main stress of the utility tunnel is better than that of the rubber concrete,but the two concretes have little effect on the structural displacement,the decrease of thickness of the shock-absorption layer can lead to the increase of the horizontal shear dislocation of the structure and the peak of the main stress on the partition wall in the middle of the structure.3)The effects of underground diaphragm wall,composite structure of diaphragm wall and shock-absorption layer,and excavation backfill on seismic response of the utility tunnel were studied.The results show that under the action of horizontal earthquake,the diaphragm wall used for maintenance pit can obviously causes the increase of the displacement and the main stress of the utility tunnel;By setting a foam concrete shock-absorption layer between the diaphragm wall and the utility tunnel structure,the negative effects of the diaphragm wall on the seismic response of the structure can be effectively reduced,under the action of horizontal earthquake,the material of excavation backfill has a significant effect on the seismic response of the utility tunnel,the use of foam concrete backfill has better performance in reducing the structural displacement response,but the use of C25 concrete backfill has advantage in reducing the main stress of the structure.Figure[25]Table[32]Reference[92]...