Abstract: The study focuses on investigating the influence of initial pores on the mechanical behavior of vesicular amygdaloidal basalt using a stochastic three-dimensional modeling method. The proposed modeling method considers calculated porosity, volume parameters, shape parameters, angle parameters, and structural parameters. Subsequently, five-factor and five-level orthogonal numerical simulations under uniaxial compression are conducted to analyze stress‒strain curves, damage modes, and failure characteristics. The calculated porosity, angle parameters, and structural parameters are found to strongly influence the uniaxial compressive strength (UCS) and elastic modulus of the rock. Specifically, the UCS and elastic modulus exhibit negative correlations with calculated porosity and angular parameters, while showing positive correlations with structural parameters. Weak correlations are observed with the remaining factors. The percentage of plastic strain in the stress‒strain curve of vesicular amygdaloidal basalt is noted to increase with increasing model porosity. The damage mode shifts from a single-shear surface, multiple-shear surface to local crush damage. Additionally, the rock transitioned from brittle to ductile failure. It is identified that a porosity of 5% and 12.5% can be approximated as critical values for the strong brittle‒brittle‒ductile transition. The established damage statistical constitutive equation is found to better predict the mechanical behavior of vesicular amygdaloidal basalt based on the initial pore. This suggests the potential importance of determining the mechanical properties of porous rocks in basaltic formations.

Key words: basalt, porous rock, stochastic modeling, numerical simulation, damage model