Soil Fabric and Soil Water Retention Curve of a Compacted Silt-Bentonites

摘要

This study presents the effects of the initial dry density and the initial water content on the soil water retention curve (SWRC) of a compacted bentonite/silt mixture during a single wetting and drying path. The samples were compacted at two different loose and dense states and at different constant initial water contents: 15% representing the dry side of the optimum, 25% representing the optimum point, and 30% representing the wet side of the optimum compacted. The initial soil fabric of each compacted sample was also studied by the mercury intrusion prosim-etry (MIP) tests. To obtain the SWRCs, two suction imposition techniques were used: the osmotic method for matrix suctions below 8.5 MPa and the vapor equilibrium technique for suctions higher than 8.5 MPa. The MIP tests were then used to fit the SWRC of each compacted sample in the degree of saturation-suction plane. The initial soil fabrics play an important role on the hydric response of the samples. Generally it can be stated that a good correspondence between MIP results and the SWRCs was found on the wetting path for the low suctions close to saturation and on the drying path for the higher suctions.