Study on the Fissure Propagation of Jointed Rock Slope Under Unloading Condition

Abstract

AbstractThe rock mass unloading is closely related to the change of geological environment, such as river valley down-cutting, frequent rainfall and evaporation, and slope excavation. For the jointed rock slope with complicated structure, these changes may trigger the propagation of cracks, posing a serious threat to slope stability and construction safety. Thus, it is necessary to analyze the fissure propagation of jointed rock slope under unloading condition. Currently, traditional finite element method (FEM) has been widely used to analyze the failure of slope because of its rigorously theoretical system. However, for discontinuous problems such as crack propagation, the result in FEM often presents high stress concentration in crack tip (numerical singularity), causing calculation to abort. In this connection, this paper intended to introduce cohesive zone model (Theory of cohesive element) from fracture mechanics to deal with the numerical singularity, and meanwhile adopt Voronoi diagram algorithm for rapidly modelling the structural planes. Firstly, a jointed rock slope model was taken as an example, discontinuity network of which was generated by Voronoi diagram, and then 0-thickness cohesive elements were embedded into structural planes to establish a numerical model. Finally, the study compared and analyzed the crack evolution of slope under different unloading conditions by changing the geometry of slope.KeywordsFemJointed rock slopeCzmVoronoi diagramCrack propagation