Determination of permeability coefficient of saturated clay based on linear segment of settlement curve

In this article, the conception of determination of permeability coefficient k based on linear segment of the settlement curve in a compression test is presented. By observing the evolution of the settlement curve of a soil, it is possible to find in its initial part a linear relation between the settlement and time. For clays, the time interval ranges from about 45 sec to a few minutes, as measured from the moment a load has been imposed. The linear character of the graph means that rheological effects are absent and that settlement velocity is constant and equal to percolation velocity. Thus, it may be supposed that within this time interval the permeability coefficient is approximately constant, too. Hence, the value of k calculated on the basis of this linear part of the settlement curve should be reliable. In this paper, the values of permeability coefficient k for clay, obtained in triaxial apparatus were compared with those obtained in oedometer test (based on the linear segment of the settlement curve). The results obtained appear to be promising. Nevertheless, since the number of tests carried out so far is rather small, it is necessary to perform more experiments to verify our conception.