Calculating cv based on non-uniform initial excess pore pressure

Abstract

The coefficient of consolidation (cv) is often determined by comparing the characteristics of the experimental and theoretical consolidation using empirical curve-fitting procedures which are based on the theoretical U−T curve generated by a layer subjected to a uniform initial excess pore water pressure distribution. However, in cases where settlement–time data are a result of a non-uniform initial pore pressure distribution, these curve-fitting procedures are no longer valid. In this technical note, a generalised procedure for Taylor and Casagrande's popular curve-fitting procedures is proposed, where the user is directed to select appropriate adjustment factors, depending on the type of non-uniform initial excess pore pressure distribution encountered. These factors were determined by approximating separate regions of the U−T curves using simple power and exponential functions. In non-uniform cases where the power approximation only captures a small portion of the U−T curve it may be difficult to use the corresponding modified curve-fitting procedure objectively.