Determination of the Shear Strength Parameters of Two Unsaturated Colluvium Soils using the direct Shear Test

Feuerharmel, C; Pereira, Allonso Curty da Silva; Gehling, Wai Ying Yuk; Bica, Adriano Virgílio Damiani

doi:10.1061/40802(189)96

Cited by 7 publications

(6 citation statements)

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“…Numerous experimental studies revealed that the moisture content of laboratory specimen can have a major influence on the strength and deformability of soils and rocks (Dyke and Dobereiner 1991;Hsu and Neson 1993;Lashkaripour and Passaris 1995;Wild 2010;Vale `s et al 2004;Fredlund et al 1987;Escario et al 1989;Rahardjo et al 1995;Cui and Delage 1996;Feuerharmel et al 2006;Chae et al 2010;Nam et al 2011;Schnellmann et al 2013). It was consistently shown that the increasing strength or stiffness, along with decreasing moisture content, is associated with capillary forces arising from both the pressure difference between the wetting and the non-wetting fluid at the gas/ liquid boundary (capillary suction), and osmotic processes (osmotic suction) in a partly saturated system composed of solids, air and water (Schmitt et al 1994;Fredlund et al 1978;Birle 2012).…”

Section: Introductionmentioning

confidence: 99%

Water Retention Characteristics and State-Dependent Mechanical and Petro-Physical Properties of a Clay Shale

et al. 2014

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A series of clay shale specimens in equilibrium with various humidity conditions were used to establish the water retention characteristics, the influence of suction on ultrasonic p-wave velocity and rock mechanical properties such as Young's modulus, Poisson's ratio, onset of dilatancy, unconfined compressive strength and Brazilian tensile strength. Opalinus Clay, a clay shale considered as host rock for the disposal of nuclear waste in Switzerland was utilized. The results showed that the p-wave velocity normal to bedding (v p,n ) dropped sharply upon desaturation until suction approached the air-entry value. The sharp decrease was associated with desiccation cracks solely oriented parallel to bedding. For suction in excess of the air-entry value, v p,n was constant, indicating no further desiccation damage. The suction at the shrinkage limit and at the airentry point is similar in magnitude. The p-wave velocity parallel to bedding (v p,p ) remained constant in the entire range of suction investigated in this study. The constant v p,p with increasing suction might be associated with the disproportional decrease in the Poisson's ratio and Young's

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Section: Introductionmentioning

confidence: 99%

Water Retention Characteristics and State-Dependent Mechanical and Petro-Physical Properties of a Clay Shale

et al. 2014

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“…Most of data on shear strength of unsaturated soils appear to have been undertaken on soils that were initially compacted to an initial water content and density and then wetted such that the initial suction was allowed to come toward a zero value (Gan et al, 2006;Vanapalli et al, 1996).…”

Section: Shear Strengthmentioning

confidence: 99%

“…Figure 3-4 Extended Mohr-Coulomb failure surface written as a function of the stress state using Fredlund et al 1978 equation Figure 3-4 shows a three-dimensional constitutive surface with matric suction plotted perpendicular to the conventional two-dimensional Mohr-Coulomb plot. The shear strength parameters c', and ϕ' are presented as saturated soil constants; however, the soil property function, f1, varies in response to the amount of water filling the voids of the soil (i.e., it is a function of matric suction)(Gan et al, 2006).…”

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confidence: 99%

Simulation of progressive shear failure in railway foundation

Vanapalli

2021

Transportation Geotechnics

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“…Similar effects on shear strength of unsaturated sand specimens were reported by Shwan and Smith (2015), assuming that measured peak strength values above expected values might be related to dilation; however, vertical displacement measurements were not reported. Röhm (1995), Feuerharmel et al (2006) and Hussain (2010) reported increased effective friction angle for increased suction. An increase in ϕ' may be observed as an increased ϕ b .…”

Section: Comparison With Prediction Modelsmentioning

confidence: 99%

Influence of extreme long-term rainfall and unsaturated soil properties on triggering of a landslide – a case study

Heyerdahl

2017

Preprint

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A case study of a natural slope in Eastern Norway that failed after extreme long-term rainfall in year 2000 was performed.Effect of soil suction on soil shear strength was investigated for intact specimens of Quaternary silt/sand, using an unsaturated shear box apparatus. Common prediction models under-predicted the unsaturated shear strength, particularly for small 10 suctions. Analyses of rainfall infiltration were performed for silt and sand slopes, based on retention curves measured in laboratory. For normal annual rainfall of 800 mm/year the model slope is theoretically stable. Extreme rainfall (240 mm in 30 days) during the autumn of year 2000 results in a rise of groundwater and loss of soil suction in the vadose zone. To reach theoretical slope failure, lower cohesion had to be assumed than measured in laboratory. High cohesion may be caused by cementation in shallow soil layers, and lower cohesion may be appropriate. Slope stability analyses based on transient seepage 15 analysis of rainfall show gradual decrease of slope stability towards slope failure (for the silt slope). With expected future increase in rainfall, more attention is needed on the role of unsaturated soil properties in rainfall triggering of landslides in different soil types, climatic conditions and geologic settings.

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Determination of the Shear Strength Parameters of Two Unsaturated Colluvium Soils using the direct Shear Test

Cited by 7 publications

References 0 publications

Water Retention Characteristics and State-Dependent Mechanical and Petro-Physical Properties of a Clay Shale

Water Retention Characteristics and State-Dependent Mechanical and Petro-Physical Properties of a Clay Shale

Simulation of progressive shear failure in railway foundation

Influence of extreme long-term rainfall and unsaturated soil properties on triggering of a landslide – a case study

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