Determination of Safety Factor for Rock Mass Surrounding Tunnel by Sudden Change of Equivalent Plastic Strain in Strength Reduction Method

The safety factor of rock mass surrounding tunnel can be determined using the strength reduction method (SRM), furthermore, it is very important to solve criterion critical state. For stability estimation tunnel, there need discuss that preferable use same criteria for slope stability, such as non-convergence finite element calculation, penetration plastic strain and sudden change horizontal displacement. by equivalent in relationship between a coefficient parameter strain. This based on elasto-plastic (FEM) SRM ABAQUS Mohr–Coulomb yield criterion. Simulation results this show how varies with geometries, friction angles cohesions circle square tunnels. also varying quality mass, pore water pressure depth.