Study on the stepped failure of rock slopes and fracture mechanism of rock bridges
The stepped failure path of the rock slope consists of joints and fractured rock bridges.To study the failure mechanism by geomechanical model testing,bottom friction tests were conducted.The fracture mechanism of the rock bridge was emphatically analyzed.Three slope models were examined including one with a stepped arrangement of low-inclination joints,one with a stepped arrangement of low-inclination and high-inclination joints,and one with a parallel arrangement of low-inclination joints.The stepped failure mechanism was revealed by analyzing the fracture evolution process of rock bridges and the displacement field characteristics.The fracture modes of the rock bridge were determined through the mechanical mechanism analysis.These modes were verified through in-situ rock mass failure,model test results,and PFC2D numerical analysis.The slope failure occurs in two modes:the multistage locking tensile type and the interlayer block tensile type.Local rock bridges undergo tensile fracture under compressive shear stress or tensile shear stress.The displacement-increasing area of the former failure mode appears in strips and expands towards the slope surface.The displacement-increasing area of the latter failure mode is flake-like and connected.The process of rock bridge tensile fracture and block splitting is shown in these two failure models.Compared to planar rockslides,different fracture paths,fracture properties,and extension directions in the rock bridge are exhibited in the stepped failure.The research results provide theoretical support for the stability analysis of rock slopes with stepped failure.
万方数据
维普
