Unsaturated Soil Response under Plane Strain Conditions Using a Servo/Suction-Controlled Biaxial Apparatus

Cruz, J. A.; Hoyos, Laureano R.; Lizcano, Arcesio

doi:10.1007/978-3-642-31116-1_5

Cited by 5 publications

(2 citation statements)

References 8 publications

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“…11), by an increase in the suction, a greater angle was obtained for the shear band to the horizontal axis increasing around 15 to 20 over the range of a suction between 0 and 55,000 kPa. (As shown, the saturated condition is represented by suction = 1 kPa) Cruz et al [19] also observed a fully developed failure surface for the unsaturated silty sand under a plane strain condition with failure angles of 61 and 65 for suctions 50 and 100 kPa, respectively.…”

Section: Shear Band Inclinationmentioning

confidence: 84%

Plane strain shear strength of unsaturated fiber-reinforced fine-grained soils

Soleimani-Fard¹,

König

Goudarzy

2021

Acta Geotech.

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Discrete randomly distributed fibers are commonly used to improve the engineering characteristics of the soil and thus soil properties such as shear strength, compressibility, density, and hydraulic conductivity. Most studies have so far focused on describing the behavior of soils containing randomly distributed fibers under dried or saturated conditions. However, the water table may seasonally fluctuate, thus generating unsaturated soil conditions. Therefore, a better understanding of the hydro-mechanical properties of unsaturated improved soils is of high necessity. In this research, the shear strength parameters of fine-grained soils were evaluated using the biaxial device available at Ruhr Universität Bochum. The applied device was modified to test unsaturated fine-grained soils with various degrees of saturation using axis translation and vapor equilibrium techniques. The experiments were conducted on fine soils containing 0, 0.5, and 1% fiber contents under a wide range of matric suctions. The ductile behavior was more noticeable in samples with lower suctions and higher straw contents. Furthermore, the shear strength of both unreinforced and reinforced fine-grained soils considerably increased by an increase in the suction. Finally, shear band inclination increased by the suction while decreasing by straw content.

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Section: Shear Band Inclinationmentioning

confidence: 84%

Plane strain shear strength of unsaturated fiber-reinforced fine-grained soils

Soleimani-Fard¹,

König

Goudarzy

2021

Acta Geotech.

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“…Several studies on unsaturated soils show that the localization of strains into planar zones of intense deformation are indeed quite common in unsaturated soils [33,34,62]. This has been observed either though biaxial experiments [32,62] or by simulating localization processes through advanced numerical techniques [13,24,45,96]. Although these observed and/or simulated localization processes exhibit phenomenological patterns very similar to those seen in saturated media [55,82], experiments and simulations are rarely inspected in light of bifurcation criteria specialized to unsaturated conditions.…”

Section: Introductionmentioning

confidence: 99%

Instability of unsaturated soils: A review of theoretical methods

Buscarnera

Mihalache

2014

Journal of Geo-Engineering Sciences

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The paper reviews a series geomechanical approaches for interpreting instabilities in unsaturated geomaterials, a class of solids involved in numerous geo-engineering problems, such as hazard forecasting, infrastructure management, underground disposal of by-products and energy technologies. The review details the connection between second-order work input, loss of controllability and material failure. Hydro-mechanical problems are addressed, focusing on a specific class of environmental perturbations that can cause sharp changes in both mechanical and hydrologic variables. A procedure to define the second-order work input to an unsaturated soil volume is discussed first. It is pointed out that this energy measure motivates the incremental form of the constitutive laws for stability analyses. It is then discussed how to link the theory of hydro-mechanical controllability with constitutive approaches for unsaturated soils, which are typically based on the framework of strain-hardening plasticity with extended hardening. In doing so, the crucial role of the properties that govern the interactions between soil skeleton and fluid-retention processes is emphasized. The implications of these findings are commented with reference to a specific application: the forecasting of landslide triggering in natural slopes. It is shown that the use of suitable stability indices allows one to differentiate between frictional slips and volumetric collapses turning into flows. These results suggest that geomechanical theories calibrated for site-specific properties can support the quantitative assessment of landslide susceptibility, as well as a number of other engineering applications involving the instability of unsaturated porous media.

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