Effects of soil skeleton deformations on hysteretic soil water characteristic curves: Experiments and simulations

Abstract

[1] Soil water characteristic curves (SWCCs) represent the relationship between suction and water content in unsaturated soils. The SWCCs exhibit hysteresis during wettingdrying cycles; however, the empirical expressions used to describe SWCCs have typically ignored the hysteresis. Additionally, the shape of the SWCC will vary depending on the void ratio of the soil and changes resulting from soil skeleton deformations, which may also show hysteretic behavior under various loading conditions. Therefore, it is important to investigate, both experimentally and theoretically, the relationship between soil skeleton deformations and the SWCC for different soils. There is limited information in the literature that examines, both experimentally and theoretically, the complex coupling between the soil skeleton deformation and SWCC behavior, and generally, this behavior is not well understood. This paper presents laboratory test results of SWCCs determined under different confining stresses on similarly prepared samples of a silty soil; drying, wetting, second drying, and scanning curves were obtained. The influence of soil skeleton deformations on SWCCs is inferred from the curves measured in an oedometer under different stress conditions. An elastoplastic phenomenological constitutive model based on the bounding surface plasticity theory was utilized to simulate the coupled mechanical-hydraulic behavior of measured results. This research demonstrates that the model is capable of predicting hysteresis in SWCCs and soil skeleton deformation and the coupling between the hydraulic and mechanical behavior of unsaturated soils.

Investigation into water retention behaviour of deformable soils

“…The volume of voids in a soil depends on the granulometry and on the state of compaction of the medium. In deformable soils, it has been evidenced that the soil deformation has an effect on the shape of the soil-water retention curve (SWRC) (Romero and Vaunat 2000;Miller et al 2002;Sugii et al 2002;Tarantino and Tombolato 2005;Salager et al 2007;Miller et al 2008;Parent et al 2011). Conventionally, the main source of deformation is the external, mechanical stress exerted on the soil.…”

Consequences on water retention properties of double-porosity features in a compacted silt

“…The water retention curve expressed in terms of water content or degree of saturation and suction is hysteretic, stress path dependent (void ratio) and depends on the pore network [1,10,16,18,19,21,23,25,27,28,31]. To properly describe its evolving water retention character, a multimodal retention model is proposed in the paper by considering a linear superposition of two subcurves of the van Genuchten [33] type.…”

Modeling of inherent anisotropic behavior of partially saturated clayey rocks

“…The symmetric second-rank tensor a(p cp ) defines the anisotropic Biot coefficients of the partially saturated material, which are dependent on capillary pressure p cp . It is noted that the skeleton deformation has a strong effect on hydraulic behavior according to previous investigations [29][30][31]. However, for simplicity, we only consider influence of capillary pressure on mechanical behavior of partially saturated material in this paper.…”

“…However, for simplicity, we only consider influence of capillary pressure on mechanical behavior of partially saturated material in this paper. Hydric responses (variations of fluid pressures with mass change and skeleton deformation) are not detailed here (see [29][30][31]). …”