Comparative Study of Nine Intact Rock Failure Criteria via Analytical Geometry

Abstract

The existing comparative studies of intact rock failure criteria do not typically consider the tensile stress zone and failure angle prediction. A new comparative study of nine intact rock strength criteria worth to list them here was performed under the framework of analytical geometry, with respect to their geometric characteristics in different cutting planes of the failure envelopes in three-dimensional space as well as predictive capacities for strength and failure angle. For this purpose, a universal failure angle formula was derived as a guideline to deduce the specific expression for each criterion. The sigma(1)-sigma(3) cutting plane displays two categories of the intact rock failure criteria: overlapping and separate compressive and tensile meridian boundaries. Experimental strength data and failure angle observation of two sandstones under complex compressive stress conditions highlight the failure criteria of Mogi-1967, Mogi-1971, nonlinear unified and Hoek-Brown in terms of strength and failure angle prediction. It is probably the first of its kind to date to evaluate different intact rock failure criteria by relating the failure angle and strength. This innovative comparative work enlightens the future advancement of the intact rock failure criterion with the consideration of the tensile stress zone and failure angle observation.