Consolidation of Nonhomogeneous Clay Layers

The application of the Terzaghi theory of consolidation of loaded clay layers assumes that the coefficients of permeability and compressibility of the clay are constant through the thickness of the stratum. However, the permeability and compressibility generally are not constants. These parameters may vary spatially, due to variations of soil type, initial state of stress, and previous stress history. The progress of consolidation in a stratum of clay through which there is a known continuous variation of the consolidation parameters is studied. A theory is presented to account for these changes. Analytical and numerical methods are presented to solve the governing equations. A series of cases are presented for variations of k and mv with depth, in which the effects of these parameters are analyzed in terms of the excess pore pressure isochrones and time-settlement relations. An analysis is presented for the consolidation of thick clay layers. The consolidation of thick normally consolidated clay layers is examined in terms of the modified theory presented; an analysis is made of the London clay, as an example.