Seismic Response Analysis And Seismic Damping Of Metro Shield Tunnel

China’s urban rail transit construction is in the stage of large-scale development of network expansion,structural improvement and rapid expansion.While the mileage of subway operations is rising,the earthquake threats faced by subway projects cannot be ignored.It is of great engineering significance to carry out seismic research on subway shield tunnels.In this paper,ANSYS numerical analysis software is used to analyze the seismic response of shield tunnel,the response of double-line tunnel under the influence of hole spacing and the shock absorption and inferiority of relevant damping measures,the study.The main research work of the thesis includes:(1)Analysis of seismic response characteristics of single-hole subway shield tunnel.Through the calculation and analysis of the finite element model of single-hole subway shield tunnel,the seismic response of the tunnel under horizontal earthquake is studied.The research shows that the displacement,velocity and acceleration response decrease in the tunnel lining from top to bottom,and the tunnel vault is the maximum response position.For the main stress response,the high stress region is "X"-shaped in the tunnel section,It means that the main stress response of the waist and the foot position is large,and the peak stress concentration falls on the inner side of the lining;the shear stress is different.Except for the dome,the inverting arch and the side wall,the high shear stress is evenly distributed over the entire lining ring surface.With the continuation of the time of the earthquake action,it reciprocates on the inner side of the lining ring.(2)Analysis of response law of double-line subway shield tunnel under the influence of hole spacing.The calculation model of the outer diameter of the tunnel is established 0.5,1,1.5 and 2 times respectively,and the variation law of tunnel seismic response under the condition that the hole spacing is the main influencing factor is analyzed.The research shows that the displacement and velocity response of the double-hole tunnel is similar to that of the single hole,but the acceleration response is opposite,showing the characteristics of large lower position and small lower position.When the hole spacing changes from small to large,all three responses are reduced.The stress response is very different from that of the single-line tunnel.The high stress areas are the dome,the inverting arch and the side wall.The larger the hole spacing,the greater the stress response.(3)Evaluation of the damping effect of each damping structure.The response of seven different shock absorbing structural models was studied and compared with the seismic response of shield tunnels without damping layer.The research shows that the aerated concrete damping layer has better damping efficiency than the rubber damping layer when only the damping layer is used;the addition of the concrete isolation wall has a significant effect on the displacement response of the tunnel,but it will greatly enlarge the stress response;replacing the isolation wall with EPS particle mixed soil will have a further damping effect compared to the use of only the damping layer.Figure[90]table[24]Reference[82]...