Elastoplastic analysis of surrounding rock of caverns considering deterioration of stiffness and strength

The stiffness and strength of the surrounding rock in underground caverns will deteriorate to a certain extent when it enters the plastic state. Based on the D-P yield criterion, the elastic-plastic solution for the anchored surrounding rock of deep-buried circular caverns is obtained considering the deterioration effects. The reliability of the method is verified by using the FLAC^3D finite difference software, and the relevant influencing factors are analyzed. The results show that: (1) Considering the deterioration of the stiffness and strength of the anchored surrounding rock, the deformation of the surrounding rock is more realistic. (2) The residual cohesion c, the residual internal friction angle φ, the residual elastic modulus E have controlling effects on the anchorage plastic residual zone radius R_b and the wall displacement u. The larger the values of c, φ, E, the smaller the values of R_b and u, and vice versa. (3) The softening moduli M_c and M_φ have great influences on the radius R_b of the plastic residual zone and the wall displacement u, but the influences on the radius R_p of the plastic softening zone can be ignored. (4) Under the coordinated action of system bolt and support resistance p_i, the scope of the plastic residual zone and the deformation of the surrounding rock can be effectively controlled.