Numerical Investigation on the Effects of Pore Location on Mechanical Properties and Failure Modes of Single-Fissured Rock Mass under Uniaxial Compression

To investigate the influence of pore position on the strength and failure modes of rock specimens containing fractures with varying dip angles, a numerical model of fractured rock with pore-fracture combinations was established using a continuous-discontinuous method. Uniaxial compression numerical simulations were conducted to explore the relationships among fracture inclination, pore position, and rock strength. Furthermore, the effect of pore position on the failure modes of fractured rocks was analyzed. The results indicate that with increasing fracture inclination, both the elastic modulus and compressive strength of intact rock (without pores) exhibit a decreasing-then-increasing trend. Meanwhile, the influence of the pore on rock strength also shows a “V-shaped” variation, characterized by an initial reduction followed by an increase;The influence of the pore on the crack propagation and coalescence patterns increases with the fracture inclination angle. In rock specimens containing fractures with dip angles ranging from 0° to 60°, the fracture dominates the failure process. In contrast, in specimens with fractures inclined at 75° to 90°, the pore plays a dominant role in controlling the failure mode༛Under the same fracture inclination, different pore positions exert varying influences on the crack propagation behavior of the rock. The presence of the pore alters the crack trajectory, leading to a clockwise deflection of the propagation path. When the inclination angles of the pore group are 42° and 61°, the pores significantly accelerate the coalescence of anti-wing cracks, leading to rapid failure. In contrast, when the pore group inclinations are 90°, 119°, and 138°, the pores exhibit limited influence on crack propagation, except for partially promoting the extension of wing cracks. These findings provide valuable insights and references for future investigations into the mechanical behavior of rock masses containing combined pore-fracture defects.