Shear displacements induced by decrease in pore solution concentration on a pre-existing slip surface

Maio, Caterina Di; Scaringi, Gianvito

doi:10.1016/j.enggeo.2015.11.007

Cited by 49 publications

(25 citation statements)

References 37 publications

(41 reference statements)

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“…[] reported that atmospheric tides can affect the slope stability and correlate with landslide velocities. A decrease in pore solution concentration (leaching of salts) is also considered to influence slope instability in marine mudstone areas [ Moore and Brunsden , ; Di maio and Scaringi , ]. Although no attention has been paid to ground temperature as a trigger for landslides, we recently reported interesting landslides that can be activated by a decrease in ground temperature [ Shibasaki et al ., ].…”

Section: Discussionmentioning

confidence: 99%

Temperature‐dependent residual shear strength characteristics of smectite‐bearing landslide soils

Shibasaki

Matsuura

Hasegawa³

2017

JGR Solid Earth

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This paper presents experimental investigations regarding the effect of temperature on the residual strength of landslide soils at slow‐to‐moderate shearing velocities. We performed ring‐shear tests on 23 soil samples at temperatures of 6–29°C. The test results show that the shear strength of smectite‐rich soils decreased when temperatures were relatively low. These positive temperature effects (strength losses at lower temperatures) observed for smectite‐bearing soils are typical under relatively slow shearing rates. In contrast, under relatively high shearing rates, strength was gained as temperature decreased. As rheological properties of smectite suspensions are sensitive to environmental factors, such as temperature, pH, and dissolved ions, we inferred that temperature‐dependent residual strengths of smectitic soils are also attributed to their specific rheological properties. Visual and scanning electron microscope observations of Ca‐bentonite suggest that slickensided shear surfaces at slow shearing rates are very shiny and smooth, whereas those at moderate shearing rates are not glossy and are slightly turbulent, indicating that platy smectite particles are strongly orientated at slow velocities. The positive temperature effect is probably due to temperature‐dependent microfriction that is mobilized in the parallel directions of the sheet structure of hydrous smectite particles. On the contrary, the influence of microviscous resistance, which appears in the vertical directions of the lamination, is assumed to increase at faster velocities. Our results imply that if slip‐surface soils contain high fractions of smectite, decreases in ground temperature can lead to lowered shear resistance of the slip surface and trigger slow landslide movement.

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Section: Discussionmentioning

confidence: 99%

Temperature‐dependent residual shear strength characteristics of smectite‐bearing landslide soils

Shibasaki

Matsuura

Hasegawa³

2017

JGR Solid Earth

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“…Moreover, the first experimental results seem to show that the water flow along the slip band can also produce a reduction in the ion concentration of the pore solution, with possible negative consequences on the soil shear strength [37][38][39][40]. On the other side, recent results of field and laboratory experimentation show that an increase of given cations in the pore fluid can increase greatly and permanently the strength parameters on the slip band and can reduce creep movements [41,42].…”

Section: Resultsmentioning

confidence: 99%

Hydraulic Conductivity and Pore Water Pressures in a Clayey Landslide: Experimental Data

et al. 2020

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To analyze the response to hydrological conditions of an instable slope in a structurally complex clay formation, the hydraulic conductivity of the subsoil was estimated and pore water pressures were monitored. Two types of field tests were carried out: falling head tests in the Casagrande piezometers and localized seepage measurements in test boreholes. The experimental data show that in a narrow band around the slip surface, the hydraulic conductivity is higher—more than two orders of magnitude—than that of the landslide body and of the stable formation. Furthermore, the data of a long-term monitoring by Casagrande piezometers and vibrating wire cells show that the response of pore water pressures to the site hydrological conditions along the shear band is far faster than in the landslide body and in the stable formation. The slip band seems largely connected to the atmosphere, and the water pressures in the band are correlated with the deep displacement rates of all the inclinometers crossing the active slip surface.

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“…Thus, expansive soils exhibit elastoplastic behavior regardless of pore fluid composition, which is similar to general clays. Moreover, a few previous studies examining the shear deformation and strength characteristics of expansive soils have indicated that the strength of expansive soils increases with confining pressure, and expansive soils finally reach the critical state. Notably, the friction angle of expansive soils depends on the pore fluid composition.…”

Section: Review Of Previous Experimental Studies On the Osmotic Behavmentioning

confidence: 99%

“…Thus, the initial interlaminar void ratio e il 0 could be determined by a calibration of the osmotic consolidation with exposure to a high‐concentration solution ( c Na+ = 4.0 mol/l), as shown in Figure for Ponza bentonite and Figure B,C for Bisaccia clay. The cation exchange capacity is set by referring to the previous study, and the other specifications of bentonite and pore water were set by referring to a previous study. Only sodium ions Na + are considered in this study.…”

Section: Model Performancementioning

confidence: 99%

A method for extending a general constitutive model to consider the electro‐chemo‐mechanical phenomena of mineral crystals in expansive soils

Kyokawa

Ohno

Kobayashi

2020

Num Anal Meth Geomechanics

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Summary The mechanical behavior of expansive soils varies according to the chemical composition of the pore fluid. It is well known that electrochemical phenomena on the surface of clay mineral crystals considerably affect their macrostructural behavior. In particular, a change in the pore fluid composition causes osmotic consolidation or swelling. In this study, a model is constructed to describe the characteristic behavior of expansive soils by coupling the interlaminar behavior of clay mineral crystals and the soil skeleton behavior. The interlaminar behavior is derived from the electro‐chemo‐mechanical coupling equilibrium of mineral crystals, and the soil skeleton behavior is given by a general elastoplastic constitutive model for soils. This modeling approach extends a general model to consider the electro‐chemo‐mechanical phenomena of mineral crystals. Oedometer tests with the replacement of the cell fluid and the swelling pressure and deformation tests on expansive clays are simulated with the proposed model. The simulation results indicate that the proposed method can reasonably represent the typical behavior of expansive soils.

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Shear displacements induced by decrease in pore solution concentration on a pre-existing slip surface

Cited by 49 publications

References 37 publications

Temperature‐dependent residual shear strength characteristics of smectite‐bearing landslide soils

Temperature‐dependent residual shear strength characteristics of smectite‐bearing landslide soils

Hydraulic Conductivity and Pore Water Pressures in a Clayey Landslide: Experimental Data

A method for extending a general constitutive model to consider the electro‐chemo‐mechanical phenomena of mineral crystals in expansive soils

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