Bearing capacity of shallow footings under reduced gravity using a seepage-controlled experimental system

The growing demand for extraterrestrial construction highlights the need to understand foundation behavior under reduced gravity. This study investigates the bearing capacity of shallow footings using a newly developed Seepage-controlled Low-gravity Experimental System (SLES), which enables long-term, stable simulation of gravity levels from g /6 to 1 g . A series of model footing tests and cone penetration tests was conducted and showed that the ultimate bearing capacity decreases linearly with gravity, but at a slower rate than gravity itself. This was accompanied by a transition in soil failure mode from general shear to punching shear. Classical cone penetration test (CPT)-based methods remain applicable for estimating the subgrade reaction coefficient, but require modification to account for gravity-dependent influence zones when predicting bearing capacity. Dimensional analysis within Terzaghi's framework confirms that gravity reduction has effects analogous to footing size reduction, and that gravity-dependent cohesion plays a significant role under low gravity. These findings may advance the theoretical and experimental understanding of soil–structure interaction across gravitational regimes and offer insights relevant to future geotechnical studies in extraterrestrial environments.