Chuanfeng Fang

Roadway cross-sectional geometry dominates surrounding rock deformation and failure, yet most existing numerical studies adopt oversimplified ideal cavities rather than practical coal mine roadway profiles, lacking systematic comparisons of real engineering section shapes. This work aims to reveal how practical cavity geometries alter rock mechanical behaviors and fracture mechanisms under uniaxial compression. Twelve equal-area cavity models corresponding to four common underground coal mine roadway types (circular, arched, rectangular, trapezoidal) were constructed, and two-dimensional discrete element method (DEM) uniaxial compression simulations were performed. The results indicate that uniaxial compressive strength and elastic modulus continuously decrease as cavity shapes shift from smooth circular arcs to angular asymmetric profiles, with degradation aggravated by increasing sharp corners; cavity geometry exerts limited influence on Poisson’s ratio but enlarges surrounding rock radial displacement at sharp edges. Angular cavities trigger severe coupled tensile–compressive–shear stress concentration, advance microcrack nucleation and expansion, and generate broader X-type conjugate shear bands, significantly weakening rock bearing capacity. This study clarifies the mesoscopic stress evolution law of rock around roadways, offering theoretical support for roadway section optimization and surrounding rock disaster prevention in underground engineering.

The pore shape is a crucial factor affecting the mechanical properties and failure characteristics of porous rock-like materials. This paper quantitatively analyzes the effects of the angularity and aspect ratio of pores on the mechanical properties of porous rock-like materials under uniaxial compression via the Discrete Element Method (DEM). Numerical models containing pores of various shapes were constructed as Voronoi polygon aggregates to more realistically reflect material fracture. The results indicate that as either angularity or aspect ratio increases, the uniaxial compressive strength and elastic modulus decrease in distinct patterns, while Poisson's ratio remains constant. Additionally, an increase in angularity or aspect ratio not only causes cracks to initiate at the sharp corner and make the crack deviate from the axial loading direction, but also results in an increase in the total length of cracks and the number of fragments. Finally, the evolution of the microstructure, including contact forces and the spatial distribution of stress, was evaluated to investigate the impact of pore shape on microscopic characteristics.