Analysis and Estimation of the Coefficient of Consolidation

Consolidation is one of the most important behaviors of saturated fine-grained soils that needs to be understood for settlement analysis of these soils. The two most important aspects of laboratory consolidation tests are: (1) estimation of the compression index (Cc), used to predict total settlement of normally consolidated soils provided the void ratio versus log (effective stress) is linear; and (2) the coefficient of consolidation (Cv), used to predict the rate of settlement in the range of primary consolidation. Several researchers have proposed various graphical methods for obtaining estimates of Cv from laboratory oedometer tests. Olson (1985) concluded that since different graphical methods estimate different values for Cv for the same data, the only rational way to estimate the Cv value is to base it on the coefficient of volume compressibility (mv) and the coefficient of permeability (k). Guided by these considerations, an attempt has been made to establish the feasibility of estimating Cv using stress state-permeability relationships (Nagaraj et al. 1993). The input parameters are the liquid-limit void ratio (eL) and the overburden pressure (p).