Failure Probability Model considering the Effect of Intermediate Principal Stress on Rock Strength

Abstract EN

A failure probability model is developed to describe the effect of the intermediate principal stress on rock strength.

Each shear plane in rock samples is considered as a micro-unit.

The strengths of these micro-units are assumed to match Weibull distribution.

The macro strength of rock sample is a synthetic consideration of all directions’ probabilities.

New model reproduces the typical phenomenon of intermediate principal stress effect that occurs in some true triaxial experiments.

Based on the new model, a strength criterion is proposed and it can be regarded as a modified Mohr-Coulomb criterion with a uniformity coefficient.

New strength criterion can quantitatively reflect the intermediate principal stress effect on rock strength and matches previously published experimental results better than common strength criteria.