Some aspects of the influence of mineralogy and moisture redistribution on the weathering behaviour of mudrocks

Olivier, H

doi:10.1016/0148-9062(81)90358-2

Cited by 14 publications

(17 citation statements)

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“…Van Eeckhout (1976) identified these expansion-contraction characteristics and the associated lengthening in internal cracking as a possible cause for the lowering in strength he observed due to humidity fluctuations. Similar observations have been made by Olivier (1979) for specimens of a Lower Triassic mudrock. With the help of water retention curves for several wetting-drying cycles between 10 and 99 % RH, Cardoso et al (2011) showed that the air-entry value of an Upper Jurassic marl decreases with an increasing number of cycles.…”

Section: Introductionsupporting

confidence: 86%

“…Few studies exist in which the influence of cycles in RH on the drying-swelling characteristics of clay shales has been investigated (e.g. Grice, 1968;Van Eeckhout, 1976;Olivier, 1979;Pham et al, 2007;Farulla et al, 2010;Cardoso et al, 2011;Yang et al, 2012;Pineda et al, 2014). Grice (1968) noted that specimens of Utica shale that were immersed in water disintegrated completely after oven drying.…”

Section: Introductionmentioning

confidence: 99%

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The response of Opalinus Clay when exposed to cyclic relative humidity variations

2017

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Abstract. Clay shale specimens were exposed to cyclic relative humidity (RH) variations to investigate the response of the material to natural environmental changes. Opalinus Clay, a clay shale chosen as host rock for nuclear waste disposal in Switzerland, was utilized. The specimens were exposed to stepwise relative humidity cycles in which they were alternately allowed to equilibrate at 66 and 93 % relative humidity. Principal strains were monitored throughout the experiments using strain gauges. After each relative humidity cycle, Brazilian tensile strength tests were performed to identify possible changes in tensile strength due to environmental degradation.Results showed that Opalinus Clay follows a cyclic swelling-shrinkage behaviour with irreversible expansion limited to the direction normal to bedding, suggesting that internal damage is restricted along the bedding planes. The Brazilian tensile strength in direction parallel and normal to bedding as well as the water retention characteristic remained unaffected by the RH variations.

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Section: Introductionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

The response of Opalinus Clay when exposed to cyclic relative humidity variations

2017

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“…1) over 8 months indicated RH values ranging between 93% and 20%. Similar records for the Orange-Fish tunnel in South Africa have been given by Olivier (1987). RH changed from full saturation to values close to 55%.…”

Section: Drying-wetting Cyclessupporting

confidence: 76%

“…In this case, the rock excavated was a carboniferous expansive mudrock. Olivier (1987) reported the strong effect of full wetting-air drying cycles on unconfined specimens. Some specimens were described as broken after two wetting-drying cycles.…”

Section: Drying-wetting Cyclesmentioning

confidence: 99%

A constitutive model for soft clayey rocks that includes weathering effects

Pinyol¹,

Vaunat²,

Alonso³

2007

Géotechnique

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Microstructural and mineralogical observations of claystones reveal the presence of clay aggregates bonded by a skeleton of inert minerals such as calcium carbonate. The behaviour of these natural materials evolves from a rock-like behaviour, when undisturbed, to clay-like soil when weathered or when subjected to straining. A model has been developed to simulate the constitutive behaviour of these transitional materials. Following the proposal made by Vaunat & Gens, the material is conceived as a composite medium made of a clay matrix and a quasibrittle bonding microstructure. The basic model has been modified and extended to reproduce the expansive behaviour of the clay matrix, a fundamental aspect to simulate weathering effects, induced largely by drying-wetting cycles. The clay matrix reacts to stress and suction changes, whereas the bond component is not affected by suction changes. An elasto-plastic double-structure model for expansive clay soils describes the clay matrix. The bonding structure follows a damage model. The interaction between the two constitutive models derives from strain compatibility conditions and energy considerations. The model performance is first illustrated by means of a sensitive analysis that explores the effect of initial bond strength, bond damage rate, bonding concentration, and wetting-drying cycles. Simple stress paths (uniaxial deformation; triaxial compression) are used to highlight the features of the formulation and the role of significant parameters. Some published tests are also reproduced with the model. They have been selected to show some relevant features of evolving soft clay rocks: stiffness and strength degradation during loading and enhanced rebound during unloading, and the effect of drying-wetting cycles on subsequent stiffness and strength degradation.

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“…The durability behaviour of these rocks is responsible for slope stability problems P. Miščević Á G. Vlastelica (&) Faculty of Civil Engineering and Architecture, University of Split, Matice hrvatske 15, 21000 Split, Croatia e-mail: Goran.Vlastelica@gradst.hr due to rapid slope degradation by the loss of strength of the surface material, unexpected additional settlements and failures of embankments, long term loss of intact strength affecting the stability of underground openings, etc. (Athmania et al 2010;Hornig 2010;Miščević and Vlastelica (2009) ;Frydman et al 2007;Gökçeoglu et al 2000;Miščević 1997;Miščević and Bonacci 1995;Johnston and Novello 1994;Anagnostopoulos et al 1991;Maekawa and Miyakita 1991;Fookes et al 1988;Olivier 1979). Of the above mentioned weak rock types, this research is focused on marls.…”

Section: Introductionmentioning

confidence: 94%

Durability Characterization of Marls from the Region of Dalmatia, Croatia

Miščević

Vlastelica

2011

Geotech Geol Eng

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Durability is one of the most important engineering properties of weak and clay-bearing rocks. Weathering can induce a rapid change in rock material from initial properties to soil-like properties. The sensitivity of a rock type against weatherability is usually described by a durability parameter, such as the slake durability index. However, marl resistance is not detected satisfactorily by the durability indices by using slake durability test as suggested by ISRM for two wetting-drying cycles. The results of this study are obtained from samples of compact or laminated eocene marls from region of Dalmatia, Croatia. The samples were subjected to 4 cycles of slake durability, point load tests, determination of dry density, determination of carbonate content and absorption of water. The scatter of data suggests that strength probably has no influence on the durability of marls. On the other hand a separate group of marl samples have a second-cycle slake durability index higher than approximately 85%, and the durability of these samples is classified as ''medium-high'' to ''high'', although the visual inspection of samples after testing, suggests that they should have ''medium'' to ''low'' durability classification. According to obtained results these samples of marl fulfil the criterions for the durability classification: a carbonate content lower than approximately 65%, a dry density lower than 2.4 Mg/m 3 , and values of water absorption higher than 5%.

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Some aspects of the influence of mineralogy and moisture redistribution on the weathering behaviour of mudrocks

Cited by 14 publications

References 0 publications

The response of Opalinus Clay when exposed to cyclic relative humidity variations

The response of Opalinus Clay when exposed to cyclic relative humidity variations

A constitutive model for soft clayey rocks that includes weathering effects

Durability Characterization of Marls from the Region of Dalmatia, Croatia

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