A modified three-dimensional Hoek–Brown criterion for intact rocks and jointed rock masses

Abstract Accurate description of the failure strength behaviors rock materials, including intact rocks and jointed masses, is essential for engineering design construction. First, a novel three-dimensional (3D) version Hoek–Brown (HB) criterion proposed in this paper. A stress weighting factor n used to describe effects intermediate minimum principal stresses. The 3D validated using six sets polyaxial test data, its prediction effect compared with that five other existing criteria. Results show exhibits smallest error most types. fitted closely correlated both partial correlation factors Then, an empirical relationship m b ( ? ) between material parameter joint dip angle developed apply masses. performance relation three expressions masses at different angles compared, best. also verified nine conventional true triaxial data. indicate predicted strengths are agreement expression form established can accurately variation value direction ? .