Structure degradation and changes in the mechanical behaviour of a stiff clay due to weathering

Cafaro, Francesco; Cotecchia, Federica

doi:10.1680/geot.51.5.441.39967

Cited by 11 publications

(19 citation statements)

References 28 publications

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“…However, beyond the yield point, the soil transits into a stress-controlled regime. Cafaro & Cotecchia [16] and Cuccovillo & Coop [17] reported Gmax to reduce after yielding at higher confining stresses. On the contrary, several other studies showed it to increase and stay above Gmax values for corresponding reconstituted clays by applying either isotropic or one dimensional oedometer compression tests.…”

Section: Introductionmentioning

confidence: 99%

Small Strain Stiffness of Artificially Cemented Soft Clay: Modelling the Effect of Structure Degradation

Khan

2019

E3S Web Conf.

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This paper presents a study on the evolution of small strain stiffness (Gmax) along vertical and horizontal directions for lightly cemented clay. Soft clays have historically been a subject for studying the evolution of stiffness anisotropy under varying loading conditions. These studies have focused on stress history (overconsolidation) effects as well. However, for lightly cemented clays, such studies are limited and their main scope has primarily been on the evolution of vertically aligned stiffness (GVH) at varying effective confining stresses. This study investigates the effect of isotropic loading on uncemented and lightly cemented kaolin clay. Kaolin clay mixed with 10% cement is used in this study. Stiffness measurements have been conducted using bender elements for obtaining GVH and GHH hence resulting in the measurement of vertical and horizontal stiffness values respectively. By comparing the behaviour of both samples, the influence of bonding and fabric due to cementation on the evolution of stiffness and anisotropy is studied. In order to characterize the behavior of structure in cemented soil with confining stress, a modelling equation is applied for the cemented sample to predict the variation of Gmax before and after yielding.

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Section: Introductionmentioning

confidence: 99%

Small Strain Stiffness of Artificially Cemented Soft Clay: Modelling the Effect of Structure Degradation

Khan

2019

E3S Web Conf.

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“…Les propriétés des terrains structurés sont changées par le processus d'altération pour aboutir à des sols pseudosurconsolidés dont les propriétés mécaniques sont dégradées par rapport aux propriétés initiales (Chandler, 1969(Chandler, , 1972Chandler et Apted, 1988). Cafaro et Cotecchia (2001) montrent que l'altération s'interprète comme une dégradation des liaisons inter-particulaires et se traduit par une réduction de la raideur du sol et de sa résistance. Maquaire et al (2003) montrent que l'altération des « Terres Noires » dans les Alpes est à l'origine de l'érosion et des ravinements des versants.…”

Section: Introductionunclassified

Divers aspects du comportement mécanique des marnes en laboratoire

Serratrice

2017

Rev. Fr. Geotech.

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-Diverses illustrations du comportement mécanique des marnes sont présentées sur la base d'exemples de résultats d'essais de laboratoire. Les marnes ont été testées dans leur état naturel au cours de programmes expérimentaux réalisés dans le cadre des reconnaissances géotechniques de massifs marneux pour des projets d'ouvrages en France. Les illustrations s'adressent à la grande variété des marnes par niveaux de difficultés expérimentales croissantes, en allant des marnes homogènes tendres vers des terrains fissurés ou altérés. Les premiers exemples concernent des marnes du point de vue de leur déformabilité, leur résistance et leur caractère isotrope ou anisotrope. Des exemples sont consacrés ensuite au comportement de marnes plus ou moins indurées, puis des marnes fissurées et des marnes altérées. Les programmes expérimentaux reposent essentiellement sur des essais triaxiaux qui sont réalisés dans une gamme étendue de pressions (0-10 MPa), ce qui permet de mettre en relief les différents aspects des comportements observés.

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“…Many authors have reported premature failures of cut slopes and embankments, constructed in stiff clays and shales (McGuffey 1982;Oakland & Lovell 1982;Šuklje 1980, among others). There have been a number of studies on the evolution of the mechanical behaviour of materials such as shales and stiff clays (Leroueil & Vaughan 1990;Cafaro & Cotecchia 2001;Sorensen et al 2007). However, very few studies deal with the behaviour of the material in actual embankments.…”

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confidence: 99%

Overconsolidated clays and flysch for embankments in Slovenia

Petkovšek

Majes

2012

EGSP

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In Slovenia 512 km of motorways have been constructed since 1994. Most of them run over hilly terrain, where the bedrock is stiff clay and soft argillaceous sedimentary rock. In order to improve the understanding of stiff clays/soft rock behaviour, series of conventional and advanced tests were performed. The inherent suction of freshly compacted material was up to 2000 kPa whereas after construction, it equilibrated at between 100 and 500 kPa. The decrease in suction resulted in material wetting and softening. Therefore, the Proctor compaction diagrams were complemented with the corresponding Soil Water Characteristic Curve (SWCC). The fundamental issue was that during compaction, inherent suction had to be maintained below a certain level and the fills had to be constructed as soil fills. For quality control, the control of soil suction was found to be important as the relative density control. The conventional monitoring with settlement plates, inclinometers and piezometers was complemented with suction and TDR probes and the seasonal water content changes were measured continuously both during and after construction. Several millions of tons of excavated flysch, shales and stiff overconsolidated clays were used for high embankments using this newly developed approach.

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Structure degradation and changes in the mechanical behaviour of a stiff clay due to weathering

Cited by 11 publications

References 28 publications

Small Strain Stiffness of Artificially Cemented Soft Clay: Modelling the Effect of Structure Degradation

Small Strain Stiffness of Artificially Cemented Soft Clay: Modelling the Effect of Structure Degradation

Divers aspects du comportement mécanique des marnes en laboratoire

Overconsolidated clays and flysch for embankments in Slovenia

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