A four-way enhanced numerical manifold method for crack propagation and failure analysis of rock slopes

摘要

A four-way enhanced numerical manifold method (NMM) is proposed in order to simulate crack propagation in rock media and progressive failure of jointed rock slopes. Specifically, the original NMM is improved in the following four aspects: (1) An "enriched local approximation" is employed to characterize singularity and discontinuity of the displacement/stress fields near the crack tip. (2) A "modified generalized Duffy transformation" is proposed to improve the accuracy of numerical integration associated with the 1/r and 1/(r~(1/2)) singularities. (3) A "critical length cracking criterion" is introduced to determine propagation length and direction for both tensile-shear and compressive-shear cracks in rock mass. (4) A "cone-complementary-based contact formulation" is incorporated to resolve the cohesive/frictional contact phenomena between discontinuous interfaces more accurately. Some examples demonstrate the performance and application prospect of the presented NMM in stability and failure analysis of the jointed rock slopes.