Internal friction angle variation in a kaolin/montmorillonite clay mix and microstructural identification

Hattab, Mahdia; Hammad, Tammam; Fleureau, Jean‐Marie

doi:10.1680/geot.13.p.081

Cited by 32 publications

(14 citation statements)

References 25 publications

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“…The obtained value of the angle of shear strength, f 0 2p , of the bentonite is in good agreement with the published data (e.g. Mesri and Olson (1970), Mesri and Olson (1971), Domitrovic and Kovacevic Zelic (2013) (Hattab et al, 2015).…”

Section: Sandssupporting

confidence: 91%

The bearing capacity of footings on sand with a weak layer

Valore

Ziccarelli

Muscolino

2017

Geotechnical Research

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Minor details of the ground, such as thin weak layers, shear bands and slickensided surfaces, can substantially affect the behaviour of soil-footing and other geotechnical systems, despite their seeming insignificance. In this paper, the influence of the presence of a thin horizontal weak layer on the ultimate bearing capacity of a strip footing on dense sand is investigated by single-gravity tests on small-scale physical models of the soil-footing system. The test results show that the weak layer strongly influences both the failure mechanism and the ultimate bearing capacity if its depth is lower than about four times the footing width. It is found that the presence of a thin weak layer can cause decreases of the ultimate bearing capacity of up to 80%. Numerical simulations, by finite-element analysis, of the behaviour of the reduced-scale models are able to capture the failure mechanism and the ultimate bearing capacity correctly, only if the mean equivalent constant value of the secant angle of shearing resistance used in calculations is selected, taking into account the curvature of the shear strength envelope of the sand within the very low normal stress range existing in the tested models.

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Section: Sandssupporting

confidence: 91%

The bearing capacity of footings on sand with a weak layer

Valore

Ziccarelli

Muscolino

2017

Geotechnical Research

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“…The primary mechanism suggested to generate failure in clay sediments is particle reorientation, forming a shear zone as the load increases [70]. However, Hattab et al [71] proposed that the mechanism of particle reorientation also depends on the content of specific clay minerals, showing that a shear plane is more likely to develop in montmorillonite as opposed to kaolinite. The stiffer and more brittle behavior of clay also results from remolding and mottling processes [41].…”

Section: Classification Of the Granular Assemblagementioning

confidence: 99%

Numerical Characterization of Cohesive and Non-Cohesive ‘Sediments’ under Different Consolidation States Using 3D DEM Triaxial Experiments

et al. 2020

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The Discrete Element Method has been widely used to simulate geo-materials due to time and scale limitations met in the field and laboratories. While cohesionless geo-materials were the focus of many previous studies, the deformation of cohesive geo-materials in 3D remained poorly characterized. Here, we aimed to generate a range of numerical ‘sediments’, assess their mechanical response to stress and compare their response with laboratory tests, focusing on differences between the micro- and macro-material properties. We simulated two endmembers—clay (cohesive) and sand (cohesionless). The materials were tested in a 3D triaxial numerical setup, under different simulated burial stresses and consolidation states. Variations in particle contact or individual bond strengths generate first order influence on the stress–strain response, i.e., a different deformation style of the numerical sand or clay. Increased burial depth generates a second order influence, elevating peak shear strength. Loose and dense consolidation states generate a third order influence of the endmember level. The results replicate a range of sediment compositions, empirical behaviors and conditions. We propose a procedure to characterize sediments numerically. The numerical ‘sediments’ can be applied to simulate processes in sediments exhibiting variations in strength due to post-seismic consolidation, bioturbation or variations in sedimentation rates.

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“…In sample 3, sand is added progressively to clay + water by steps of 5 to 10 g. Distilled water is used to mix sand and clay. Many researchers adopted 1.5 WL of the clay as the initial water content to mix sand-clay mixtures [12][13][14][15]. Whereas in this paper, the initial water content to mix sand and clay is 1.5 WL of the sand-clay mixture (50% to 50% in weight) which measured by Atterberg limits tests (see Table 3).…”

Section: Sample Preparationmentioning

confidence: 99%

Influence of sample preparation on the multi scale structure of sand-clay mixtures

Yin¹,

Fauchille²,

Othmani³

et al. 2019

E3S Web Conf.

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This paper focuses on the influence of sample preparation on the multi scale structure of sand-clay mixtures. Three different protocols to mix silica and kaolinite were tested in the laboratory to identify the one providing the most homogeneous microstructure. From the macroscopic to the microscopic scales, optical observation, 3D X-ray tomography, 2D scanning electron microscopy (SEM) and 2D environmental scanning electron microscopy (ESEM) were carried out on wet and dry samples. This paper provides a first insight on the mechanisms of sand clay mixing from the cm to μm scale. Preliminary results demonstrate that the microstructures of the samples prepared by the three procedures have similar macroporosities based on imaging techniques. However, the preparation which consists in mixing the sand firstly, followed by water and clay provides a more homogeneous microstructure with silica grains well-surrounded by an oriented clay layering, probably due to a geometrical effect. Understanding the formation of the oriented clay layering brings microstructural features that will help to better explain the grain displacements and rotations during direct shear tests, the behaviour at the pile sand-clay soil interfaces and to formulate sand clay microstructure models.

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Internal friction angle variation in a kaolin/montmorillonite clay mix and microstructural identification

Cited by 32 publications

References 25 publications

The bearing capacity of footings on sand with a weak layer

The bearing capacity of footings on sand with a weak layer

Numerical Characterization of Cohesive and Non-Cohesive ‘Sediments’ under Different Consolidation States Using 3D DEM Triaxial Experiments

Influence of sample preparation on the multi scale structure of sand-clay mixtures

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