Estimation of mechanical parameters of Tongji-1 lunar soil simulant based on cone penetration test

Abstract

The mechanical properties of the lunar soil, e.g. the bearing capacity and the deformation modulus, are of great importance for the design of the foundations of permanent lunar outposts. To measure these two parameters, the plate loading test (PLT) is a reliable and the most popular method on the Earth, but is not directly applicable on the lunar surface due to the difficulties in setting up the test equipment. An alternative and indirect method is the cone penetration test (CPT) mainly due to its simplicity in operation. The current study concentrates on the relationships between the two mechanical parameters obtained from PLTs and the penetration resistance obtained from CPTs. Both PLTs and CPTs were carried out on Tongji-1 lunar soil simulant (TJ-1 simulant) in a calibration chamber to establish their relationships and then on a large-scale man-made ground to validate the relationships. The test results show that: the link between the acceptable bearing capacity q a, the deformation modulus E 0 and the average penetration resistance q avg was established and validated as: q a = 0.25/D 0.63 q avg and E 0 = 7.16q avg for TJ-1 simulant ground. They can be used directly in the foundation design for lunar outposts.