Experimental and numerical studies of the hydromechanical behaviour of a natural unsaturated swelling soil

Nowamooz, Hossein; Mrad, M.; Abdallah, Adel; Masrouri, Farimah

doi:10.1139/t08-127

Cited by 36 publications

(3 citation statements)

References 24 publications

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“…The volume change potential (VCP) under cyclic W/D shows different behavior responses. Some studies, e.g., [5,6,9,44,45,48], have concluded that this cyclic process results in cumulative swell strains, while others have shown swell fatigue (i.e., accumulated shrinkage), e.g., [1,3,4,8,13,24,32,[36][37][38]47,49,50], and was explained as the soil particles exhibited continuous rearrangement, leading to a less active microstructure. The results of [12][13][14]34,44] reported both swell and shrinkage accumulation at the end of this cyclic process.…”

Section: Introductionmentioning

confidence: 99%

Simulating the Hydraulic and Volume Change Behavior of Compacted Highly Expansive Soil under Potential Field Stress and Seasonal Climatic Variation

Abbas

2023

Sustainability

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A sustainable design of some engineering applications, such as earth dam cores, landfill liners, clay barriers, and radioactive waste disposal systems, that utilize compacted expansive soils requires simulation for probable field conditions. This study investigated the hydraulic and volume change (H-VC) behaviors of highly expansive compacted soils in Al-Qatif city under different seasonal climatic variations for a wide range of stress conditions, aiming for more economical and rational design and practices. The extent of the effect of the start cycle condition of the cyclic wetting and drying (W/D) process on the examined properties is examined, as well. Two testing series of the cyclic W/D process, representing the probable seasonal climatic variations, were executed for varied axial stress conditions. The H-VC behaviors of expansive soils are affected by the simulated seasonal variation (i.e., cyclic W/D process), with the first cycle of W/D being the most effective cycle and an elastic state being attained by the third to fourth cycle. Swell fatigue is noted for both testing series, and this is attributed to the initial placement condition. Analysis of results recommends exposure of the compacted expansive soil layers in the field to drying after compaction to reduce their equilibrium wetting potential. As a consequence of the noted shrinkage accumulation, a reduction tendency of saturated hydraulic conductivity (ksat) with repeated W/D cycles is reported for both series under all the stress states applied. Finally, it is recommended for clay barrier projects to be submerged once compacted to obtain barriers with the lowest values of hydraulic conductivity.

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Section: Introductionmentioning

confidence: 99%

Simulating the Hydraulic and Volume Change Behavior of Compacted Highly Expansive Soil under Potential Field Stress and Seasonal Climatic Variation

Abbas

2023

Sustainability

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“…This includes exposure to wetting from the saturated host rock and drying from the hot nuclear spent fuel [48], which makes the characterisation of the water retention behaviour of these materials particularly important. The water retention behaviour of clays is also relevant to other applications including, for example, the prediction of settlements under superficial foundations, the study of groundwater flow and the design of agricultural irrigation systems [3,44,69].…”

Section: Introductionmentioning

confidence: 99%

A water retention model accounting for void ratio changes in double porosity clays

et al. 2021

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This paper presents a constitutive model that predicts the water retention behaviour of compacted clays with evolving bimodal pore size distributions. In line with previous research, the model differentiates between the water present inside the saturated pores of the clay aggregates (the microstructure) and the water present inside the pores between clay aggregates (the macrostructure). A new formulation is then introduced to account for the effect of the macrostructural porosity changes on the retention behaviour of the soil, which results in a consistent evolution of the air-entry value of suction with volumetric deformations. Data from wetting tests on three different active clays (i.e. MX-80 bentonite, FEBEX bentonite, and Boom clay), subjected to distinct mechanical restraints, were used to formulate, calibrate, and validate the proposed model. Results from free swelling tests were also modelled by using both the proposed double porosity model and a published single porosity model, which confirmed the improvement in the predictions of degree of saturation by the present approach. The proposed retention model might be applied, for example, to the simulation of the hydromechanical behaviour of engineered bentonite barriers in underground nuclear waste repositories, where compacted active clays are subjected to changes of both suction and porosity structure under restrained volume conditions.

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“…This behavior was explained by the continuous rearrangement of the soil particles, leading to a less active microstructure. In contrast, Chu and Mou [5], Pousada [6], Nowamooz [7] and Nowamooz et al [8] observed the opposite effect, in which the amount of swelling strains increases with the number of successive cycles. All of these tests showed that the equilibrium elastic state could be reached at the end of several cycles.…”

Section: Introductionmentioning

confidence: 99%

Volumetric strains due to changes in suction or stress of an expansive bentonite/silt mixture treated with lime

Nowamooz

Masrouri²

2010

Comptes Rendus. Mécanique

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Experimental and numerical studies of the hydromechanical behaviour of a natural unsaturated swelling soil

Cited by 36 publications

References 24 publications

Simulating the Hydraulic and Volume Change Behavior of Compacted Highly Expansive Soil under Potential Field Stress and Seasonal Climatic Variation

Simulating the Hydraulic and Volume Change Behavior of Compacted Highly Expansive Soil under Potential Field Stress and Seasonal Climatic Variation

A water retention model accounting for void ratio changes in double porosity clays

Volumetric strains due to changes in suction or stress of an expansive bentonite/silt mixture treated with lime

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