Gravity Effect on Cone Penetration in Lunar Regolith Simulant

The cone penetration test (CPT) provides an important means of evaluating the geotechnical response of lunar regolith for future lunar exploration and infrastructure development. In this study, CPTs were performed on a lunar regolith simulant under terrestrial gravity (1g) and simulated lunar gravity (1/6g) using the geotechnical magnetic-similitude-gravity model testing (GMMT) method. Three-dimensional discrete element method (DEM) simulations were conducted and validated against the measured cone-resistance profiles, after which the validated model was used to investigate particle rearrangement, stress-path evolution, and three-dimensional stress transmission. Reducing gravity from 1g to 1/6g decreased the simulated cone resistance by approximately 24-33% over penetration depths of 100-300 mm. Reduced confinement facilitated local particle rotation and rearrangement but weakened the penetration-induced stress-bearing network. The attenuation exponents of the radial, circumferential, and vertical stress components changed from -1.18 to -1.34, -1.07 to -1.39, and -1.32 to -1.71, respectively, while the characteristic vertical-stress influence radius decreased from approximately 2.78R to 1.65R. These results quantitatively link macroscopic cone resistance to particle-scale rearrangement and three-dimensional stress transfer, providing a basis for interpreting CPT measurements and evaluating near-surface mechanical responses in lunar regolith.