Numerical simulations of the effect of bolt inclination on the shear strength of rock joints

摘要

Joints are widely encountered in rock engineering. They damage the continuity and the integrity of a rock mass, thus turning the rock anisotropic and unstable. Therefore, investigations on the shear strength and deformation of rock joints are essential. Current researchers on joints primarily focus on joint mechanical characteristics, especially shear strength, by experimental and analytical methods [1-15]. For simplicity, some studies place joints on flat planes [5]. However, rock joint parameters are difficult to determine because of the unclear differences between theory and reality in terms of the interactions between engineering and geological bodies. Simplifying joints to flat states and disregarding undulating states is impractical. Therefore, certain scholars have investigated joint characteristics through joints with irregular surfaces or different undulation angles. Patton [7] demonstrated the influence of surface roughness on the shear strength of joint by means of an experiment in which he carried out shear tests on 'saw-tooth' specimens. Barton and Bandis [9,11,14,15] proposed a criterion for the shear strength of rock joints based on a large number of joints tests, which takes into account both slip under low normal stresses and asperity crushingunder high stresses. Barton and Choubey [9] proposed standard profiles of joints to determine the coefficient JRC in Barton-Bandis criterion. Fox [16], Lee [13] and Jafari [17] studied the stress-strain property of joints under cycling shear load. Li et al. [18] employed artificial concrete joint samples with saw-tooth-shaped surfaces to study the strength of joints with various undulation angles under different shearing velocities.