Effective Stresses in Soil and Rock and Consolidation in Three Dimensions

In the following, the continuum model for a fully saturated porous material is presented. The theory is mainly due to M.A. Biot [?, ?]. We shall only consider a twophase system consisting of a solid skeleton and a single pore fluid, e.g. water. The theory for three-dimensional consolidation is developed. Anisotropic permeability of the material is allowed, but for simplicity the analysis is restricted to isotropic linear elastic material behaviour. However, the theory is easily extended to elastoplasticity. Finally, it will be shown that the effective stresses in a porous material may in general not be calculated as proposed by Terzaghi. Whereas highly accurate results are achieved for residual soils, i.e. sand, silt and clay, poor results are obtained for cemented materials such as concrete sand, silt and clay, poor results are obtained for cemented materials such as concrete and rock. Here it is recommended to follow the stress approach proposed by Biot.