Ridge slope failure mode analysis using strength reduction method based on double shear unified strength criterion

Abstract

Intermediate principal stress (IPS) may influence the stability of a slope under three-dimensional (3D) failure modes. However, the influence of IPS is seldom considered in slope stability evaluation. In this study, the 3D stability and failure mode of a ridge slope is analyzed by considering the influence of IPS. The mathematical model of double-shear unified strength theory was established using the UMAT subroutine in the Abaqus software. The influence of IPS on the deformation and damage modes of the homogeneous ridge slope was studied using strength reduction method. The results calculated by the Mohr-Coulomb strength criterion were very close to those the unified strength UMAT subroutine. Both have a safety coefficient of approximately 1.6. When the IPS coefficient b was 0, the safety factor was 6.95. And when the IPS coefficient increased to 0.2, the stability factor of the double-sided ridge slope was 9.44. The slop stability was enhanced obviously due to the existence of the IPS. After the excavation of the ridge side slope, the rock mass of ridge slope was not failure easily at the ridge line of the double-sided ridge slope. However, the rock mass at the side of the flank was prone to cracking damage. Moreover, the rock mass was prone to extrusion failure at the foot of the double-sided ridge slope. The calculations provide a new method and knowledge on the concrete evaluation of the failure and stability of a slope.