A Method to Determine cv Under Sinusoidal Pore Pressure Distributions

Abstract

The coefficient of consolidation (cv) is traditionally evaluated by fitting experimental settlement-time data to the theoretical percentage consolidation-time factor curve of a layer subjected to a uniform initial excess pore water pressure (ui) distribution. Over the years, numerous curve-fitting techniques have been developed for this experimental-theoretical correlation, the most popular of which are Casagrande's logarithm-of-time method and Taylor's square-root time method. These classical curve-fitting techniques have recently been generalized to account for a variety of different ui distributions. In this paper, basic consolidation principles have been applied in a novel fashion to both standard and tall oedometer tests on two clays to simulate a sinusoidal ui distribution (operating under either singly or doubly drained conditions) within a laboratory setting. The settlement-time data obtained from these tests were analyzed using the modified curve-fitting procedures previously put forward by the authors to determine appropriate values for cv, which were found to closely align with values of cv obtained using the traditional Taylor and Casagrande methods, when the ui distribution is considered uniform. The most valuable feature of these modified curve-fitting techniques was found to be their ability to analyze traditionally obtained settlement-time data to supplement any conventionally obtained cv values. This is useful in terms of validation when settlement-time data do not exhibit the usual trends and traditionally calculated values of cv require further authentication.