Void Characteristics and Seismic Response of Tunnel Lining in High-intensity Earthquake Zones for High-speed Railways
To enhance the safety of railway tunnels with diseases in high seismic areas,a tunnel inspection vehicle was used to test 29 high-speed railway tunnel linings for voids behind them.The influence of voids on the safety of tunnel structures was studied using the fi-nite difference method.The results indicate that voids behind the lining of high-speed railway tunnels are prone to occur at the arch crown,accounting for 80.00%of occurrences.The most frequent range of longitudinal length for voids is from 2 m to 4 m,representing 46.49%of occurrences.The minimum distance between voids and the lining surface is mainly distributed in the range of 0.3 m to 0.55 m,accounting for 78.93%.Voids are often associated with defects in the thickness of the lining.Voids behind the lining alter the contact state between the surrounding rock and support,leading to changes in the inertial force and forced displacement of the structure.Displacement and stress states subsequently change.Voids result in changes in the internal forces of the structure in their respective locations,reducing the safety factor of the structure by 19.51%to 95.27%.As the void's circumferential angle,radial depth,and longitudinal length increase,the safety factor of the structure decreases.The cavity behind the lining will significantly reduce the seismic safety of high-speed railway tunnel lining.The research findings can provide a reference for seismic defense measures for high-speed railway tunnels with defects.
railway tunnelhigh-speed railwaylining voidsseismic responsehigh-intensity earthquake areas