Effect of low vacuum on density and stress-strain-strength behavior of lunar soil simulant

Proposals to establish a manned base on the moon have necessitated the in-depth study of the engineering properties of the lunar regolith. In this investigation, the density and stress-strain-strength behavior of a lunar soil simulant in low vacuum were studied. A lunar soil simulant was produced from crushed terrestrial basalt rock and a vacuum triaxial stress device was designed, fabricated, and operated. The simulant was compacted to ultimate density, subjected to one-dimensional stress while constrained, and then subjected to triaxial states of stress. Vacuum levels ranged from 760 torr to 0.004 torr. Confining stresses considered were 0.10 MPa, 0.14 MPa, and 0.17 MPa. Low vacuum was found not to have any significant effect on the density or the stress-strain-strength behavior of the simulant as compared to results of tests at atmospheric pressure.