Modified criteria for sliding and non-sliding failure of anisotropic jointed rocks

• Modified failure criteria are proposed for transversely isotropic rock with through-going joint.
• The proposed criteria take account of nonlinearity of strength variations as well as the effects of confining pressure on the anisotropy.
• The proposed criteria require less experimental tests for determination of their parameters (compared with the original ones).
• Laboratory tests are conducted to verify the proposed criteria.
• An equation is derived to estimate the critical confining pressure above which the anisotropy is vanished.

Modified failure criteria are proposed to estimate sliding and non-sliding strength of anisotropic rocks containing single or a set of parallel well-defined discontinuities. A newly modified form of Mohr–Coulomb relation is incorporated into two well-founded failure criteria namely Jaeger’s criterion and Tien–Kuo criterion. Some input parameters of the proposed criteria may be indirectly determined using empirical correlations extracted from the literature. Consequently, the strength of anisotropic jointed rocks can be evaluated more easily and accurately compared with current failure criteria. Another advantage of the proposed criteria is that their use does not require any curve fitting procedure since the parameters can be estimated through the given relations. The concept of critical confining pressure is also assessed in more detail and an equation is proposed to predict the confining pressure above which discontinuity has no effect on the strength. In addition, laboratory tests are carried out to evaluate the theoretical results and it is shown that the proposed criteria are of acceptable accuracy and applicability.