Constitutive and Stability Behavior of Soils in Microgravity Environment

摘要

The constitutive behavior of soils such as strength, stiffness, and localization of deformations are to a large extent derived from interparticle friction transmitted between solid particles and particle groups. Interparticle forces are highly dependent on gravitational body forces. At very low effective confining pressures, the true nature of the Mohr-Coulomb strength envelope, which is the criterion most frequently used, is unclear both with respect to interparticle friction and cohesion. Because of the impossibility of eliminating gravitational body forces on earth, the weight ofsoil grains develops interparticle compressive stresses which mask true soil constitutive behavior even in the smallest samples of models. Therefore the microgravity environment induced by near-earth orbits of spacecraft provides unique experimental opportunities for testing theories related to the mechanical behavior of soils. Such materials may include cohesionless soils, silt, clay, industrial powders, crushed coal, etc. This paper discusses the importance of testing soils under very low confining stresses, effects of gravity on the stress-strain behavior of sand, and examples of potential future experiments on soils in microgravity environment aboard the space shuttle or the International Space Station.