Influence of stress and suction on volume changes and microtexture of a Ca-smectite

摘要

The volume change behavior of clays depends on the hydro-mechanical stress state and physico-chemical properties. This paper deals with the effects of stresses and suctions on volume changes and on parameters that are obtained from X-ray diffraction, such as interlamellar distances. The material studied is a Ca-smectite French clay (FoCa). Experiments have been performed on this clay as powder or paste in initial state. Concerning the mechanical experiments, a large range of suctions and mechanical stresses is covered. Suctions from 0.2 MPa to 155 MPa are applied, requiring different techniques such as osmotic or salt solutions. These techniques are adapted to oedometric cells to perform hydro-mechanical tests allowing to study the behavior under low to high mechanical stresses, from a few kPa to 10 MPa. The history of the material seems to be of major importance on its microscopic and macroscopic behavior under the hydro-mechanical stresses.