The mechanical behaviour of rock specimens with specific edge crack distributions under triaxial loading conditions

Abstract

Research on the mechanical behaviour of rock masses with multiple joints has become a popular topic and has practical applications in natural slope stability. This paper aims to clarify the influence of joint geometry, joint orientation and joint connectivity ratio on the mechanical behaviour of rock specimens containing two pre-existing joints. Triaxial compression tests were conducted under various confining pressures to simulate the variation in external conditions. An exponential criterion was used to describe the relationship between the axial stress and confining pressure. The experimental crack propagation was explored by varying the joint orientation, joint connectivity ratio and confining pressure. The structural plane with a greater angle of inclination controlled the failure of the rock sample. Two failure patterns were observed under the loading conditions: shear failure and mixed failure. The failure surface trajectory presented similar deviations with the increase in joint inclination angle, joint connectivity ratio and confining pressure, which also accelerates the transition from mixed failure to shear failure. The experimental results highlight the significance of elucidating the influence of structural planes in practical engineering to predict the stability of natural slopes.