Effects of intermediate principal stress on rock cavity stability

The linear Mohr-Coulomb and nonlinear Hoek-Brown failure criteria, which neglect the effects of intermediate principal stress, are widely used in soil and rock engineering. However, much experimental data shows that the failure envelope relates to the intermediate principal stress. Employing the failure criterion and the generalized plastic potential function, the stability of rock cavity driven in an isotropic and homogeneous medium was investigated under the condition of plane strain considering the effects of intermediate principal stress. The closed-form solutions for stresses and displacement around a rock cavity were given in the elastic and plastic zones. Based on the closed-form solutions, the intermediate principal stress has an important effect on cavity stability.