Influence of dip directions on the main deformation region of layered rock around tunnels

摘要

The influence of dip directions on the main deformation region of layered rock around tunnel is studied using a 3D distinct element code called 3DEC. We learn that the main deformation regions around tunnels are regularly changeful along with different intersection angles between dip direction and advancing direction of the tunnel. The specific deformation regions can be anticipated based on detailed engineering geological survey before tunnel excavation. Moreover, the common deformation pattern around tunnels is found to be structural deformation including bending and slipping of layered rock. The main deformation region is prone to occur at the region where the normal direction of rock layer points to the inside of tunnel because the minimum tensile strength of bedding plane appears on this region and rock bending is generally easier than rock slipping. An understanding of the main deformation regions around tunnels provides critical information for selecting the route of a tunnel, forecasting the main deformation region and designing an efficient support system.