Geotechnical Properties of Lunar Soil Analogue VI-75 in Dry and Frozen State

The lunar soil analogue VI-75 fully corresponds to typical lunar regolith in terms of particle morphology, grain-size distribution, and physical-mechanical properties. It is actively used in various experimental studies and tests of space equipment and scientific instruments. This study investigates additional physical and mechanical characteristics of the lunar soil analogue VI-75, such as the angle of repose and the coefficients of subgrade reaction, which are essential for modeling and calculations when planning the placement of infrastructure for a permanent scientific lunar station on the Moon's surface. It is also shown that the water ice content in lunar soil can significantly alter its mechanical properties and greatly increase its strength characteristics. For example, doubling the water ice content in lunar regolith almost doubles its strength properties. The study addresses the rate of water migration due to gravity from the upper layer of the analogue to the lower layer and provides recommendations for preventing undesirable water migration during the preparation of experiments with frozen soil on large-scale test stands.