Transport in Porous Media 32: 49–74, 1998. c  1998 Kluwer Academic Publishers. Printed in the Netherlands. 49 Chemo-Mechanical Consolidation of Clays: Analytical Solutions for a Linearized One-Dimensional Problem MARIUSZ KACZMAREK ⋆ and TOMASZ HUECKEL Duke University, Durham, NC 27708-0287, U.S.A. (Received: 2 July 1997; in final form: 26 January 1998) Abstract. Consolidation (and swelling) of clayey soils caused by change in chemistry of pore fluid is addressed. Such phenomena are caused by changes in the concentration of various species in the solution and result primarily from a stress-independent deformation of individual clusters, and from a mechanical weakening or strengthening of the clay solid matrix in the presence of stress. Second, transport of chemicals that involves concentration gradients induces additional driving forces of osmotic consolidation due to semipermeable membrane nature of clay. In this paper an extension of Terzaghi’s model of the mechanical consolidation to incorporate chemical loading of soil is proposed. A linearized model is used to solve analytically two one-dimensional problems of consolidation of a homogeneous layer simulating a landfill liner with drained or undrained boundaries. The numerical results show a strong dependence of distribution of pore pressure on the chemical load and chemically induced settlements of soil to be comparable to the mechanical ones. Key words: chemo-mechanical consolidation, swelling pore-fluid chemistry. 1. Introduction This paper addresses consolidation and swelling induced in soils by a nonmechanical cause: change in pore fluid chemistry. The change of chemical content of pore fluid constitutes chemical loading which may affect hydraulic and mechanical behavior of rocks and soils in a number of engineering as well as natural environmental problems. Engineering importance of chemical swelling has been traditionally associated with the soil heave due to change in pore water salinity and with electro-osmotic technolo- gies. More recent technologies, where chemical consolidation plays a major role are electro-kinetic remediation and settlement of liners of landfills or impoundments affected by chemicals. In particular, it was found that an alteration of physico- chemical interaction between solid and pore fluid caused by a change in chemical content of pore fluid may induce deformation of soils, see Bolt (1956), Greenberg et al. (1973), Sridharan and Venkatappa Rao (1973), Mitchell (1993), Barbour and Fredlund (1989), Fernandez and Quigley (1991). Possible microscopic and macro- scopic mechanisms leading to the observed changes in hydraulic conductivity and in mechanical properties of clays are discussed by Hueckel et al. (1997) and Hueckel (1997). ⋆ Address for correspondence: Department of Environmental Mechanics, College of Education, Bydgoszcz, Chodkiewicza 30, 85-064 Bydgoszcz, Poland.