The 5th International Symposium on Slope Risk and Resilience

Understanding the mechanical behavior of lunar regolith is fundamental for upcoming lunar exploration and infrastructure development. However, the scarcity of returned samples and the limitations of conventional simulants necessitate high-fidelity numerical modeling. This study establishes a novel Discrete Element Method (DEM) framework to investigate the mechanical behavior of Chang'e-5 lunar regolith by simultaneously incorporating realistic particle morphology, the actual particle size distribution, and distance-dependent interparticle adhesion. High-fidelity particle shapes, including spherical, columnar, flat, and bladed forms, are reconstructed from micro-CT images of over 5000 particles (Wu et al., 2025), and represented using bonded sphere clusters, while faithfully replicating the measured size distribution. A new surface-based adhesive contact model is developed to simulate van der Waals forces between irregular particles. Numerical triaxial tests were conducted to analyze macroscopic strength from peak to critical state (Figure 1). The simulated dense specimen (porosity=38%) exhibited peak strength parameters (friction angle φ=43.5°, cohesion c=3.77 kPa) and critical state parameters (φ=37.3°, c=2.44 kPa). The loose specimen (porosity=46%) showed lower peak strength (φ=40.2°, c=2.21 kPa) and a critical state of φ=38.2° and c=2.14 kPa. Our results indicate that the presence of adhesive forces significantly enhances cohesion but has a negligible effect on the friction angle. Microscopic analysis reveals that adhesion stabilizes the contact network and suppresses particle rotation, which are key strengthening mechanisms. The findings highlight the critical interplay between particle morphology and interparticle adhesion, providing essential insights for lunar surface engineering.

lunar regolith,micro-CT imaging,discrete element method,particle morphology,interparticle adhesion