Mechanics of Unsaturated Soils

Laloui, Lyesse; Nuth, Mathieu; Baudin, François

doi:10.1002/9781118616871.ch2

Cited by 8 publications

(5 citation statements)

References 17 publications

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“…Compared with the loess of the Gansu area, loess clay minerals in Shanxi Province are mainly mixed-layer minerals, with a decreasing chlorite content but with increasing montmorillonite, resulting in a stronger cohesive force. Loess cements are mainly clay minerals that act as cementation (kaolinite, illite, montmorillonite and chlorite), various salts, organic material and so on; however, the insoluble salts (mainly calcium carbonate) in Heifangtai loess not only act as a skeleton, but also act as cementing metrial (Laloui et al, 2010). In addition, montmorillonite has a crystal cell structure with three layers and the binding strength between unit cells is weaker.…”

Section: Discussionmentioning

confidence: 99%

Experimental study of loess disintegration characteristics

Wang

Zhang

et al. 2019

Earth Surf Processes Landf

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Loess structures with large joints and fissures often undergo natural disintegration when subjected to contact with water. The slaking of loess results in the formation of loess gullies, caves, and landslides. To study the disintegration properties and the factors influencing them, we carried out field and laboratory tests. First, we carried out an in situ disintegration test using different sample shapes obtained from Heifangtai and analysed the effect of soil sample shape on loess disintegration. We then developed an improved disintegrator and tested the effect of different factors on the disintegration of loess. The effects of water content, salinity, and composition on disintegration are discussed. The results show that the loess disintegration process can be divided into three broad stages – wetting, softening, and subsidence – the disintegration is mainly concentrated in the third stage, while the first two stages are short and show very weak disintegration. The main factors influencing the disintegration of loess samples are shape, size, and clay mineral content. During the in situ disintegration test, the edge angles of soil samples are disintegrated, to soften all their edges. Disintegration duration increases with increasing sample size, but the extent of disintegration was found to decrease. Disintegration duration is inversely proportional to the loess disintegration rate. The loess disintegration rate is positively correlated with water temperature within a certain range; however, the reverse is observed with soil sample size and initial water content, and salinity was found to have little effect on the disintegration rate. Higher clay content of cohesive soil and weaker permeability leads to a slower disintegration rate. Additionally, lower cementation may easily cause loess disintegration. © 2019 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

Experimental study of loess disintegration characteristics

Wang

Zhang

et al. 2019

Earth Surf Processes Landf

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“…Experiments demonstrate that the residual shear resistance—which can control the kinematics and evolution of first‐failure landslides after large displacements, landslides in the reactivation state, bedding shears, sheared joints, and faults (Bromhead, ; Leroueil, ; Skempton, )—depends on a number of parameters, such as the mineralogy of the solid skeleton and the particle shape (e.g., Chattopadhyay, ; Di Maio & Fenelli, ; Kenney, ; Li et al, ), the chemical composition of the pore fluid (e.g., Di Maio, ; Di Maio & Fenelli, ; Fan, Xu, Scaringi, Li, et al, ; Pontolillo et al, ; Scaringi, ), and the normal effective stress accounting for the state of saturation (e.g., Laloui et al, ). Furthermore, the residual shear resistance is not independent of the shear displacement rate.…”

Section: Introductionmentioning

confidence: 99%

Shear‐Rate‐Dependent Behavior of Clayey Bimaterial Interfaces at Landslide Stress Levels

Scaringi

et al. 2018

Geophysical Research Letters

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The behavior of reactivated and first‐failure landslides after large displacements is controlled by the available shear resistance in a shear zone and/or along slip surfaces, such as a soil‐bedrock interface. Among the factors influencing the resistance parameter, the dependence on the shear rate can trigger catastrophic evolution (rate‐weakening) or exert a slow‐down feedback (rate‐strengthening) upon stress perturbation. We present ring‐shear test results, performed under various normal stresses and shear rates, on clayey soils from a landslide shear zone, on its parent lithology and other lithologies, and on clay‐rock interface samples. We find that depending on the materials in contact, the normal stress, and the stress history, the shear‐rate‐dependent behaviors differ. We discuss possible models and underlying mechanisms for the time‐dependent behavior of landslides in clay soils.

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“…The compaction should be performed at an adequate water content of the soil that allows optimizing the density for a given energy of compaction. In addition to the natural binding effect of the argillaceous material, capillary cohesion contributes, for a big part, to the total strength of the materials [17,28]. This is related to the internal suction which is related to the co-existence of gas and liquid phases in the void space.…”

Section: Introductionmentioning

confidence: 99%