Variation of consolidation coefficient of expansive clays at high initial water content

Abstract

The coefficient of consolidation is a fundamental parameter for estimating the rate of settlement of structures found on saturated clayey layers. In this study, twelve series of one-dimensional consolidometer tests were performed on both undisturbed and remoulded/reconstituted samples of an expansive clay from Western Australia. The aim of this study is to investigate the variation in coefficient of consolidation at high initial water contents. The consolidometer tests start at very low consolidation stress (3 kPa) and increase to the relatively high-stress level of 1600 kPa to consider the effect of stress level on the results. The results show that the initial water content, stress level, and clay mineralogy have a great impact on the coefficient of consolidation. Moreover, the physicochemical factor governs the compression behaviour of remoulded samples prepared at initial water contents less than the liquid limit, and reconstituted samples at initial water contents higher than the liquid limit at medium to high-stress levels. Therefore, the coefficient of consolidation decreases with increasing consolidation stress for such samples. On the other hand, the mechanical factor mainly controls the compression behaviour of reconstituted samples at low-stress levels, and there is an increasing trend of the coefficient of consolidation with consolidation stress. In addition, the results also show that sample disturbance has a great influence on the coefficient of consolidation by decreasing the value by approximately four times.