Rate and acceleration effects on residual strength of kaolin and kaolin–bentonite mixtures in ring shearing

Duong, Nguyen Thanh; Suzuki, Motoyuki; Hai, Nguyen Van

doi:10.1016/j.sandf.2018.05.011

Cited by 25 publications

(28 citation statements)

References 31 publications

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“…Besides these effects, the behaviour of clays depends not only on the material state, but also on the strain amplitude. Researchers [6][7][8][9][10][11][12][13][14][15] have found that clays behave elastically only under very small strain amplitudes je 1 j\0:01 %. Under medium strain amplitudes 0:01 %\je 1 j\1 %, the so-called small strain effects, namely the stiffness increase due to reversal loading and the reduction in the plastic strain rate, take place.…”

Section: Introductionmentioning

confidence: 99%

AVISA: anisotropic visco-ISA model and its performance at cyclic loading

Tafili

Triantafyllidis

2020

Acta Geotech.

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In this work, a constitutive model able to capture the strain rate dependency, small strain effects and the inherent anisotropy is proposed considering the influence of the overconsolidation ratio (OCR). Small strain effects are captured by using an extended ISA plasticity formulation (Fuentes and Triantafyllidis in Int J Numer Anal Methods Geomech 39(11):1235-1254, 2015). The strain rate dependency is reproduced by incorporating a third strain rate mechanism (in addition to the elastic and hypoplastic strain rate). A loading surface has been incorporated to define a three-dimensional (3D) overconsolidation ratio and to account for its effects on the simulations. Experimental investigations using Kaolin Clay and Lower Rhine Clay with horizontal bedding plane have shown that under undrained cycles of small strain amplitudes (\10 À4), the effective stress path in the p-q space is significantly inclined towards the left upper corner of the p À q plane. Consequently, a transversely (hypo)elastic stiffness has been successfully formulated to capture this behaviour. The performance of the model has been inspected by simulating the database of approximately 50 cyclic undrained triaxial (CUT) tests on low-plasticity Kaolin Clay (Wichtmann and Triantafyllidis) considering different deviatoric stress amplitudes, initial stress ratios, displacement rate, overconsolidation ratio and cutting direction. Furthermore, 4 CUT tests conducted on high-plasticity Lower Rhine Clay were simulated, whereby the influence of the displacement rate, as well as the deviatoric stress amplitude, has been analysed. The simulations showed a good congruence with the experimental observations.

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Section: Introductionmentioning

confidence: 99%

AVISA: anisotropic visco-ISA model and its performance at cyclic loading

Tafili

Triantafyllidis

2020

Acta Geotech.

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“…e consolidation process would be finished until the end of the primary consolidation, which was confirmed by judgment based on the 3t-method [30,31]. e method has been widely used for the preparation of preconsolidation samples in the laboratory test in Japan [32][33][34]. After finishing the consolidation process in the tank, the vertical load was unloaded, and the cylindrical tank containing the sample was removed from the top and bottom plates.…”

Section: Methodsmentioning

confidence: 99%

Consolidation Characteristics of Artificially Structured Kaolin‐Bentonite Mixtures with Different Pore Fluids

Duong

Hao

2020

Advances in Civil Engineering

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The consolidation characteristics of kaolin, bentonite, their mixtures, and natural clays have been widely evaluated. However, the effect of pore fluid on the consolidation characteristics of artificially structured kaolin-bentonite mixtures should be more investigated. In this study, the oedometer tests were carried out on mixtures of kaolin with 10%, 20%, and 30% bentonite reconstituted with distilled water and 1 M NaCl. The testing samples with an “artificial structure” were prepared using the preconsolidation procedure. The test results show that bentonite greatly affects the consolidation behavior of mixture samples, especially when the pore fluid is distilled water. In the case of distilled water, the addition of bentonite to kaolin clay significantly increased the compression index (Cc), swelling index (Cs), and coefficient of volume change (mv). In this case, the mv of mixture samples increased significantly at low effective axial stress (σ′a) levels (less than the preconsolidation pressure) and then decreased as the σ′a further increased. In the case of 1 M NaCl as the pore fluid, the Cc, Cs, and mv slightly changed with the increase of bentonite content. The research results also confirmed that the effect of saline water on the compression index was noticeable when the liquid limit of soil with distilled water was higher than 110%, and the compression index of soil with distilled water was higher than 1. Regarding the coefficient of consolidation (Cv), the Cv of kaolin sample increased as the σ′a increased, and this trend was independent of the pore fluid chemistry. By contrast, the Cv − σ′a trend of mixture samples depended not only on the pore fluids but also on the stress level.

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“…Compared with reversal direct shear and triaxial compression tests, ring shear tests have been preferentially adopted to determine the residual shear strength of soil, due to their ability to shear unlimited displacements [6][7][8]. Many factors, such as shearing rate, moisture content, surface roughness, consolidated state, and temperature, affect the magnitude of the residual soil strength [9][10][11][12][13][14][15][16]. Among these factors, the loss of strength caused by the shearing rate (greater than 100 mm/min) explains the high acquired velocity of landslides [17,18].…”

Section: Introductionmentioning

confidence: 99%

“…10 Geofluids 300 kPa and shearing rate of 393 mm/min). The mean size (D 50 ) decreased from 14.51 μm (original sample) to 11.68 μm (sample with a normal stress of 300 kPa and shearing rate of 393 mm/min).4.5.2.…”

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confidence: 99%

Effects of High Shearing Rates on the Shear Behavior of Saturated Loess Using Ring Shear Tests

Zhao

et al. 2021

Geofluids

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The shear behavior of saturated loess was examined by performing a series of ring shear tests with different shearing rates. The effects of shearing rates on the shear behavior of saturated loess with different normal stress are presented and discussed. The results showed that peak shear strength and steady-state shear strength were greater when the shearing rate was low and vice versa. Compared with high and low shearing rates, the maximum strength reduction ratios of peak shear strength and steady-state shear strength were 34.2% and 37.2%, respectively. The axial displacement during shearing was measured and was found to increase with increasing shear displacement in all tests. A comparison of sample height reduction (when the shear rate was stopped) found that the low shearing rate test sample underwent a much greater reduction than the high shearing rate test sample; however, the variation reduction range was within 4 mm. Monitoring the pore-water pressure during the shearing process revealed that it increased with shear displacement, and a higher excess pore-water pressure was generated within the shear zone during the fast-shearing process. Comparing the particle size distribution of the samples after the test and the original sample showed that the particles were crushed during the shearing process. The percentage that was finer than 0.005 mm increased with shearing rates and normal stress, and the soil structure implosion became more pronounced with increasing normal stress.

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Rate and acceleration effects on residual strength of kaolin and kaolin–bentonite mixtures in ring shearing

Cited by 25 publications

References 31 publications

AVISA: anisotropic visco-ISA model and its performance at cyclic loading

AVISA: anisotropic visco-ISA model and its performance at cyclic loading

Consolidation Characteristics of Artificially Structured Kaolin‐Bentonite Mixtures with Different Pore Fluids

Effects of High Shearing Rates on the Shear Behavior of Saturated Loess Using Ring Shear Tests

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