Bearing capacity of lunar soil ground under extraterrestrial environmental effects

Abstract

Lunar environment features a low gravity field and ultra-high vacuum which shows significant effects on the bearing behavior of lunar soil ground for future lunar habitation. Therefore, the 2D Discrete Element Method was employed to simulate the plate load tests under different gravity fields in non-vacuum (i.e., excluding the van der Waals force) and high-vacuum (i.e., including the van der Waals force) environments, analyzing the bearing behavior and soil response under extraterrestrial environmental effects. The results show that a bilinear line bounded by 1g can be employed to describe the gravity effect on the gravity factors for ultimate bearing capacity and coefficient of subgrade reaction. The slopes are different in low and high-gravity fields, indicating that the high-gravity effect in a centrifuge cannot be directly applied to predict the bearing behavior of lunar soil ground in a low-gravity field. The affected area becomes deeper in depth and narrower in width with the decreasing gravity level in non-vacuum environment, while the affected area becomes deeper in depth and wider in width with the decreasing gravity level in high-vacuum environment. Such observations can provide advice for developing analytical models for the bearing capacity of lunar soil ground considering the extraterrestrial environmental effects.