Percussive Excavation and Its Nullifying Effect on the Influence of Soil Relative Density

Excavation in low gravity environments produces a problematic force imbalance between soil shear strength and excavator body loads. The same body forces which normally overcome a soil's shear strength are insufficient in low gravity. Consequently, percussion is being researched as a means of reducing a soil's in situ shear strength. By applying percussion to the soil-tool interface during excavation the interlocking particle forces, soil dilatancy, within a dry granular soil are mitigated. As applied percussive frequency is increased there is an exponential decay in the excavation baseline draft force. In addition, the continuity of shear plane formation increases inhibiting a soil's ability to strain-harden. Given these outcomes, it is concluded that the effect of a soil's in situ relative density, in the context of dilatancy, is nullified.