CHEMOMECHANICAL CONSOLIDATION OF CLAYS - ANALYTICAL SOLUTIONS FOR A LINEARIZED ONE-DIMENSIONAL PROBLEM

Consolidation (and swelling) of clayey soils caused by change in chemi stry of pore fluid is addressed. Such phenomena are caused by changes in the concentration of various species in the solution and result pri marily from a stress-independent deformation of individual clusters, a nd from a mechanical weakening or strengthening of the clay solid matr ix in the presence of stress. Second, transport of chemicals that invo lves concentration gradients induces additional driving forces of osmo tic consolidation due to semipermeable membrane nature of clay. In thi s paper an extension of Terzaghi's model of the mechanical consolidati on to incorporate chemical loadings of soil is proposed. A linearized model is used to solve analytically two one-dimensional problems of co nsolidation of a homogeneous layer simulating a landfill liner with dr ained or undrained boundaries. The numerical results show a strong dep endence of distribution of pore pressure on the chemical load and chem ically induced settlements of soil to be comparable to the mechanical ones.