Arching Effect of Planetary Regolith Simulant under Extraterrestrial Gravities

Abstract

Attention has been devoted to the construction of off-earth base construction and mineral mining in recent years. This paper studies the influence of extraterrestrial gravities on the arching effect surrounding deeply buried structures in planetary regolith using trapdoor experiments. Off-earth regoliths are physically simulated using a magnetically sensitive planetary regolith simulant, whereas the gravities are simulated by applying a uniform magnetic body force. The results show that the gravity has a significant influence on both the unloading rate for soil pressure on the trapdoor and the reduction in soil pressure. Both soil pressure and normalized soil pressure unload rapidly when moving the trapdoor down at a lower gravity. The unloading rate for soil pressure increases when gravity increases. However, that of the normalized soil pressure decreases. With further increases in gravity, the normalized soil pressure appears to reach a stable state. A theoretical solution for the soil pressure on the trapdoor is proposed which includes the effect of gravity-induced stress level and stress gradient on interparticle friction resistance. The predicted soil pressure demonstrates good agreement with the experimental results. This study provides an approach to estimate the downward loading on trapdoor-like underground structures in off-earth engineering applications.