Complex jointed rock masses are common in nature. When a roadway is located in complex jointed rock mass, numerous joints can weaken the strength of surrounding rock, resulting in large deformation of the roadway and impact on mine production. In this paper, a DFN–DEM jointed roadway model was constructed based on discrete element method, with the failure characteristics and layout optimization of roadway analyzed. Also, the mechanical properties of jointed rock masses with different sizes and rotation angles were numerically investigated. And the failure and deformation characteristics of jointed roadway with different layout angles were analyzed. The results demonstrated that the UCS of jointed rock masses under different loading directions are significantly different, with an RVE size of 6 m. UCS of the jointed rock masses reaches maximum value at the rotation angles of 30° and −60°, and the average UCS of rock masses has a positively relationship with the joint density P₃₀. The shear instability of joints results in the macro-failure of rock masses, and brings about the asymmetric failure of jointed roadway. The layout angle of jointed roadway can significantly affect its failure and deformation characteristics. With the roadway axial direction adjusted to −60° relative to the direction of principal stress, the deformation degree of the surrounding rock reached minimum values. In engineering practice, an optimal layout angle and supporting of jointed roadway are effective for avoiding the large deformation of surrounding rock.

Jointed rocks under local load are ubiquitous in civil engineering. The instability and failure of jointed rocks are fatal to engineering safety. This paper numerically investigated the effects of loading area and joint angle on the strength dividing points, energy evolution, and crack distribution characteristics of non-persistent jointed rocks. The results demonstrated that the closer the absolute value of joint angle to 45° and the smaller the loading area, the lower the strength dividing points of rocks. The curves of rock joint angle versus total energy at peak and of elastic energy versus amplitude of post-peak abrupt energy change render a W-shape distribution. Meanwhile, compared with joint angle, loading area has more influence on rock energy input. The larger the loading area, the higher the crack fractal dimension, the crack entropy, and the penetration rate. Tensile cracks outnumber shear cracks when jointed rocks are damaged, and shear cracks increases significantly at the post-peak stage.