A Proposal for Estimating Strength Parameters of Lunar Surface from Soil Cutting Resistances

For future lunar and planetary exploration activities such as in-situ resource utilizations and surface operations, an idea for estimating both c and φ of the lunar surface was proposed. The strength parameters were estimated from the soil-tool response involved in soil cutting processes with blades That is to say, the soil cutting is considered as an in-situ testing, and the boundary problem is inversely analyzed to determine c and φ through a soil-tool interaction model. The method of stress characteristics was used to establish the theoretical model. Moreover, laboratory model tests for the soil cutting were performed using a lunar soil simulant to investigate force-distance behavior and verify the validity of the proposed estimation method. As a result of the verifications, it became clear that the estimated strength parameters are in agreement with drained strength parameters obtained from direct shear box tests. Hence it can be said that there is a possibility that soil cutting process may enable the strength characterization of the lunar surface.