Effects of joint roughness and inclination on fracture behavior of jointed rock under true triaxial compression

True triaxial compression experiments were conducted on jointed rock with different Joint Roughness Coefficient (JRC, JRC = 4.78, 9.57, 14.74 and 19.47) or inclined angle (α = 30°, 45°, 60° and 90°) firstly. Then, the adaptive transform a Lagrangian solid element to Discrete Element Sphere particles (adaptive Solid to DES) method was employed to realize the true triaxial compression simulation on jointed rock with various JRC and α. The results show that: (1) The maximum equivalent stress and cracks are firstly concentrated at the joint asperities and develop into the rock matrix with increasing axial stress, resulting in joint-matrix coupled fracture mode. (2) The strength and peak strain of the jointed rock show a decreasing (30 ° ≤ α ≤ 60°) then increasing α = 90°) tendency as the α increased. Increasing JRC weaks the influence of α on strength but amplify on peak strain. (3) When the joint strike parallels to intermediate principal stress, the failure mode are matrix shear (α = 30°), matrix shear-joint sliding (α = 45°), joint sliding (α = 60°), to matrix shear failure (α = 90°), respectively. When the joint strike parallels to minor principal stress, the larger stress on the inclined side inhibits the influence of the joint, resulting in all jointed rock matrix shear fracture.