Research on the combined damping technology of shallow buried large-section loess tunnel

Due to the uniqueness of loess structures and properties and the higher seismic technical requirements for tunnel engineering, it is imperative to study the seismic response of damping loess tunnels. Based on the Xichengshan tunnel project, a three-dimensional numerical model is established by finite element software to analyze the stress and strain response of the structure under different spacing of shock absorption joints and different stiffness lining. The combined damping measures of " rigid lining+ shock absorption joint " are proposed, and the damping effect of the combined damping measures is further analyzed. The results show that the setting of the shock absorption joint can effectively reduce the dynamic response of the loess tunnel under earthquake, and the recommended value of shock absorption spacing of the loess tunnel is 10 m. The dynamic response of the structure is different with different lining stiffness. The greater the stiffness, the greater the structural stress and the smaller the deformation. The combined damping measures of " rigid lining + shock absorption joint " can give full play to the advantages of single damping measures and effectively reduce the damage of earthquake to loess tunnel.