Farimah Masrouri

Long-Term Behavior of Lime-Treated Clayey Soil Exposed to Successive Drying and Wetting

The positive effects of lime treatment are likely to be altered by weathering, and the sustainability of lime-treatment positive effects is in question. In this study, the effects of successive drying/wetting cycles on the hydromechanical properties of a lime-treated clayey soil are assessed. Osmotic suction-controlled oedometers were used to determine the swelling/shrinkage behavior of soils subjected to successive drying/wetting cycles of small amplitude. Significant degradation of the yield stress was observed while the efficiency of the treatment on volumetric behavior remained unchanged, this being related to the stabilization process. This study showed that the evaluation of the mechanical sustainability of a lime-treated material subjected to wetting and drying cycles requires tests in realistic conditions.

Effect of Density in the Water Retention Curve of a Compacted Silt-Bentonite Mixture

In unsaturated swelling-shrinking soils, like clay soils, water content change results in significant volume change and drying is associated with high water content gradients.This work presents initially the soil water retention curve (SWRC) of a bentonite-silt mixture compacted at three different initial dry densities (1.27, 1.35 and 1.55 Mg.m− 3). The SWRCs were fitted by the van Genuchten (1980) and Brooks and Corey (1964) type functions. The estimated parameters were used to model the SWRC of the intermediate samples.

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

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 prosimetry (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.

Soil Fabric of Compacted and Natural Swelling Soils Studied by Mercury Intrusion Porosimetry

This article compares the Pore Size Distribution (PSD) study of two different fine graded swelling soils, in natural state, and remoulded at the same initial state. The soil fabric of these clayey soils including the macropores, mesopores, and micropores was mainly studied by the mercury intrusion porosimetry (MIP) technique. For both soils, the results showed clearly that the soil fabric of the remoulded samples compacted in the laboratory are significantly different from the natural ones. Therefore, as the artificial compacted samples do not correctly represent the natural soil fabric, hydro-mechanical parameters measured on them would be different from those obtained on the intact natural samples.