Research On Seismic Response And Damping Measures Of Parallel Double Tunnel

In recent years,with the rapid development of national economy,the scale of underground space structure has become larger and larger,and underground building structure has become an essential part of infrastructure construction.China is a country with frequent earthquakes.Compared with the above ground structure,the underground structure investment is relatively large.Underground structure is very important.Once it is damaged,it is difficult to repair again,and its loss is immeasurable.Firstly,this paper introduced the stress characteristics of double tunnel,analyzed the surrounding rock pressure of double tunnel,expounded three dynamic constitutive models of soil under dynamic action,introduced the basic theory of dynamic finite element method,and focuses on the basic principle and characteristics of viscoelastic artificial boundary.Secondly,the main structure model of a subway tunnel is established using Midas GTS three-dimensional finite element analysis software.Different seismic waves were selected to carry out seismic calculation and analysis,and the results of dynamic time history analysis were compared.The results show that the maximum relative displacement of the soil is mostly at the soil boundary under the effect of the seismic wave,and the maximum relative displacement of the tunnel lining is mostly at the tunnel portal.Then,the seismic response of parallel double tunnel with different tunnel spacing,tunnel depth,surrounding rock level and other factors under the effect of transverse seismic load and the three-dimensional seismic response characteristics of parallel double tunnel were studied.The results show that the tunnel portal section has a great influence on the dynamic response of seismic load.From the beginning to the middle part of the tunnel,the maximum principal stress of the tunnel lining structure decreases gradually.In the range of tunnel portal,the decrease range of maximum principal stress is relatively large,and the decrease range is relatively small in the middle.Finally,in order to research the damping effect of the tunnel damping measures,the damping layer was used as the damping measures,and the damping effect of the damping layer was studied by numerical simulation.The results show that the damping layer can absorb the energy of the seismic wave,reduce the damage of the tunnel caused by the seismic load,and effectively reduce the shear stress of the lining of the parallel double tunnel.