Interface Shear Behavior of MGS-1 and JEZ-1 Martian Regolith Simulants

Abstract

The mechanical behavior of Martian regolith–structure interfaces is of great significance for the design of Mars rover and excavation tools, as well as for infrastructure construction for Mars exploration. This paper aims to understand the basic interface response of MGS-1 and JEZ-1 Martian simulants. The characteristics of simulant–simulant and simulant–steel interface are investigated by a direct shear apparatus in the laboratory. The compression properties of the two Martian regolith simulants are also investigated by one-dimensional oedometer tests, finding that both MGS-1 and JEZ-1 are less compressible and lower swelling soils. The direct shear results indicate that the peak and residual cohesion of MGS-1 and JEZ-1 are less than 8 kPa. The peak internal friction angles (38.8°–40.6°) of MGS-1 and JEZ-1 are lower than two previously tested typical simulants (i.e., JSC Mars-1 and MMS-1) with values ranging between 5.4° and 10.0°, while the residual friction angles (38.2°–39.7°) are similar to those of JSC Mars-1 and MMS-1. All the adhesion values of the smooth and rough interfaces are lower than 5 kPa. For the tests employing a smooth steel plate, resulted in peak interface friction angles of MGS-1 and JEZ-1 are 17.6° and 18.9°, and the residual interface friction angles are of 14.5° and 16.7°, respectively. For the tests employing a rough steel plate, the peak interface friction angles of MGS-1 and JEZ-1 are 38.3° and 36.2°, and the residual interface friction angle values of 33.4° and 33.2°, respectively. The interface friction angles of MGS-1 and JEZ-1 are lower than the corresponding internal friction angles. The properties of simulant–steel interface obtained from this paper provide information for the design and construction of humans’ settlement infrastructure, and are also of interest for spacecraft hardware development for future Mars exploration.