Variation of the hydraulic conductivity of Boom Clay under various thermal-hydro-mechanical conditions

Abstract

In this paper, an experimental study is presented that intended to investigate (1) the anisotropy properties of hydraulic conductivity of Boom Clay, (2) the effect of heating-cooling cycle on the hydraulic conductivity and intrinsic permeability of Boom Clay, and (3) the effect of loading-unloading cycle on the hydraulic conductivity and intrinsic permeability of Boom Clay. Constant-head tests were carried out in a temperature-controlled triaxial cell. First, the anisotropic characteristic of hydraulic conductivity of Boom Clay with respect to its bedding was confirmed. The horizontal hydraulic conductivity (parallel to bedding) is larger than the vertical hydraulic conductivity (perpendicular to bedding).Second, there was a positive and reversible relationship between the hydraulic conductivity and temperature and a negative and irreversible relationship between the hydraulic conductivity and hydrostatic pressure.Specifically, for both horizontal and vertical hydraulic conductivity, the value at 80 °C is approximately 2.4 times larger than that at room temperature (23 °C). However, it appears that the hydraulic conductivity is not sensitive to heating rate. Data analysis reveals that under variable temperature conditions, the changes in viscosity and density of water with temperature are the main factors affecting the change in hydraulic conductivity of Boom Clay with temperature, although other factors may have an effect to some extent.3

Seepage mechanisms and permeability differences between loess and paleosols in the critical zone of the Loess Plateau

“…In addition, loess contained hydrophilic clay minerals, which had a strong ability to adsorb bound water and caused particle surfaces to adsorb more bound water (Revil & Lu, 2013;Stepkowska et al, 2004). Therefore, the presence of bound water on particle surfaces meant that the physical and chemical properties were different from coarse-grained soil (Lei et al, 2019;Ma et al, 2016;Singh & Wallender, 2008). The (Nguyen et al, 2013;Singh & Wallender, 2008;Wang et al, 2011).…”

“…Fine-grained soil has viscosity, plasticity and swelling due to the presence of bound water between particles (Dolinar, 2009;Mojid & Cho, 2012;Prost et al, 1998). Finegrained soil physical and mechanical indexes are controlled by microscopic properties such as clay mineral composition, surface potential, pore water type, and so on (Deng et al, 2014;Ma et al, 2016;Nguyen et al, 2013;Wang et al, 2012). Therefore, the study of these properties helps us to understand the permeability behaviour of finegrained soil.…”

Investigation on the Influence of Temperature and Confining Pressure on the Hydraulic Conductivity of the Integrated and Fractured Jurassic Conglomerates

“…In our conglomerate sample case, the relationships of hydraulic conductivity with temperatures of 10°C, 20°C, 28°C, 35°C, and 50°C show a nonlinear variation. Ma et al [19] presented an experimental study investigating the anisotropic properties of the hydraulic conductivity of Boom clay and the corresponding influence of the heating-cooling cycle. The results show that the hydraulic conductivity is not sensitive to the heating rate, but there is a positive relationship between the hydraulic conductivity and temperatures of 23°C, 40°C, 60°C, and 80°C.…”