Predicting residual friction angle of lunar regolith based on Chang'e-5 lunar samples

With the rapid development of human lunar exploration projects, the lunar base establishment and resource utilization are on the way, and hence it is urgent and significant to reasonably predict engineering properties of the lunar regolith, which remains to be unclear due to limited lunar samples currently acces-sible for geotechnical tests. In this contribution, we aim to address this outstanding challenge from the per-spective of granular material mechanics. To this end, the 3D multi-aspect geometrical characteristics and mechanical properties of Chang'e-5 lunar samples are for the first time evaluated with a series of non-destructive microscopic tests. Based on the measured particle surface roughness and Young's modulus, the interparticle friction coefficients of lunar regolith particles are well predicted through an experimental fitting approach using previously published data on terrestrial geomaterials or engineering materials. Then the residual friction angle of the lunar regolith under low confining pressure is predicted as 53 degrees to 56 degrees according to the particle overall regularity and interparticle friction coefficients of Chang'e-5 lunar samples. The presented results provide a novel cross-scale method to predict engineering properties of the lunar regolith from particle scale information to serve for the future lunar surface engineering construction.(c) 2023 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

Automated summary

With limited access to lunar samples for geotechnical tests, accurately predicting the engineering properties of lunar regolith is urgent and significant. In this study, the 3D geometrical characteristics and mechanical properties of Chang'e-5 lunar samples are evaluated for the first time through non-destructive microscopic tests. By utilizing particle surface roughness and Young's modulus, the interparticle friction coefficients are predicted, and the residual friction angle of lunar regolith is estimated to be between 53 degrees and 56 degrees under low confining pressure. These findings present a novel method for predicting the engineering properties of lunar regolith, which can be valuable for future lunar surface engineering construction.