Seismic Response Analysis of Surrounding Rock of Deep Buried Tunnel Crossing Active Fault Zone
Tunnel engineering accounts for a large part of the road and railway projects in the dangerous mountains in southwest China.This area has large tunnel burial depth,complex geological conditions and frequent seismic activities.There are several engineering problems with small angle crossings between tunnel engineering and active faults.In addition,near-field earthquakes have different influences on surrounding rocks with different burial depths.Therefore,near-field earthquakes of active faults have significant adverse influences on the smooth construction and safe operation of tunnel engineering.Therefore,based on the impact of multiple disastrous earthquakes at home and abroad on tunnel engineering,the influence rules of historical earthquake magnitude on the damage of surrounding rock(surrounding rock burial depth,lithology and grade)of tunnels passing through the seismogenic fault are analyzed and summarized.Combined with the characteristics of active faults,the ground motion records that can reflect the regional fault characteristics and pulse characteristics are obtained.Finally,the finite difference software FLAC3D is used to study the influence of the active fault near-field earthquake on the surrounding rock of deep tunnel engineering.The results show that the tunnel surrounding rock is more stable with the increase of tunnel buried depth,which can restrain the plastic deformation of tunnel surrounding rock.The trend of maximum shear stress and maximum principal stress under different ground motions is basically the same,and the stress of tunnel surrounding rock in fault section is greater than that in ordinary section.The surrounding rock of Grade IV and below has a great displacement and stress response when the depth of tunnel is 200m and PGA is larger than 0.3g.The response level increases with the increase of PGA,and there is a large increase of nearly 50%in the process of PGA from 0.2g to 0.39g.This process is the main process of tunnel plastic deformation,and the area of plastic zone gradually increases with the increase of PGA.Therefore,the influence of near-field earthquakes should be carefully considered in deep-buried tunnels through active faults.The research results can provide technical support for seismic optimization design of tunnel.
active fault zonenear-field earthquaketunnel surrounding rockdynamic responsenumerical simulation
万方数据
维普
