Study on Shock Absorption Measures of Highway Tunnel in Karst Areas

Based on soil-structure interaction model, the response analyses of the Menglian tunnel by using viscous-spring artificial boundary and time history analysis method under earthquake accelerations and multiform conditions of surrounding rocks are presented. The seismic responses of the tunnel are calculated by changing parameters of surrounding rocks within certain influencing distances to the linings. The shock absorption effects, applicability, and shock mechanisms of grouting in the surrounding rock are analyzed. The results show that the displacements and stresses of the tunnel linings in karst areas decrease by grouting in the surrounding rock, under the high-intensity seismic load, and the linings are protected when the grouting measure is used. It also shows that the shock absorption effect is better with the increase of the grouting density and range. By calculating analysis, it can achieve the shock absorption effects when the grouting range is 5.5 to 7.0m in the Menglian tunnel. The results provide useful reference for the shock absorption design of tunnel.