Construction of porous DEM specimens for seafloor massive sulfides and their uniaxial compression behavior

Seafloor massive sulfides (SMS) exhibit high porosity and weak cementation, promoting core fragmentation and reducing core recovery during deep-sea coring. Pore structure significantly affects the mechanical properties and failure behavior of SMS. This study proposes a DEM-based approach to construct porous DEM specimens with controllable porosity, pore size, and spatial distribution. Using these specimens, uniaxial compression simulations are performed under varying porosity P and pore-size control parameter η to analyze the effect of pore structure on the compressive response of SMS. The results show that the uniaxial compressive strength and elastic modulus decrease markedly as P increases. The influence of η on the mechanical response is porosity-dependent. When P<30%, the differences in specimen strength and stiffness among different η values are limited. When P≥30%, specimens with larger η values generally show higher uniaxial compressive strength and elastic modulus. Contact force-chain analysis indicates that, under high-porosity conditions, larger η values help preserve the continuity of local strong force chains, leading to relatively higher strength and stiffness. Further analyses of cracks and fragments show that pore structure changes the crack propagation paths and post-failure fragment distribution of the specimens, thereby affecting the final fragmentation pattern of SMS.