Elastic-plastic response of tunnel in GZZ-based constitutive model

Abstract

Investigating the stress redistribution characteristics after tunneling is critical for designing and constructing deeply buried tunnels. Three-dimensional stresses are more prominent in deep than in shallow tunnels, resulting in nonlinear strength. The generalized Zhang–Zhu (GZZ) criterion captures the nonlinear strength well. Therefore, this study established a 2D plane-strain numerical model using a GZZ-based constitutive model. The effects of the axial stress and rock properties on the stress redistribution and plastic zone are discussed. The initial axial stresses changed the axial stress distribution after excavation and had little effect on the radial and tangential stress distributions. The size of the plastic zone decreases with decreasing geological strength index and increasing rock mass mi . However, with increasing dilation coefficient, the stress distributions remained almost unchanged, whereas the radial deformation gradually increased.