Nonlinear empirical failure criterion for rocks under triaxial compression

Abstract

Based on existing triaxial compression experimental data, a new empirical failure criterion with wide applicability was proposed considering hydrostatic pressure, second stress invariance, and maximum shear stress. Four fitting evaluation indicators were used to verify the consistency of the new failure criterion, and the differences with the other 6 failure criteria were discussed. The characteristics of the new failure criteria in the principal stress space were finally analyzed. The results indicate that (1) the new failure criterion exhibits strong predictive ability for triaxial experiments and has good applicability for both intact and jointed rocks; (2) the influence of hydrostatic pressure on the failure surface exhibits a non-linear trend, and different hydrostatic pressure also exhibits different distribution patterns on the deviatoric stress plane, with a distribution characteristic pattern of hexagonal snowflake-regular hexagon. The maximum shear stress has a torsional effect on the new criterion, in the three-dimensional failure surface. The parameters a and b of the rock have an impact on the failure surface morphology of the new criterion function on the offset surface.

Keywords

• Failure criterion
• Intermediate principal stress
• Geotechnical materials
• True-triaxial experiment
• Rock mass strength