A note on the shrinkage behaviour of a clay paste under various loads

Talsma, T

doi:10.1071/sr9770275

Cited by 28 publications

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“…Reeve & Hall provided shrinkage lines only for P = 0. Because the shrinkage lines at different values of P cannot ‘cross over’, the slope of the shrinkage lines at constant ϑ varies only slightly with P (Talsma, 1977). With reasonable accuracy one can therefore equate α cc to the slope of the unloaded shrinkage line:…”

Section: Theory and Methodsmentioning

confidence: 99%

Re‐evaluation of the structural properties of some British swelling soils

Groenevelt¹,

Grant²

2001

European J Soil Science

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Summary The structural condition of swelling soils can be assessed from their shrinkage curves. We re‐evaluated data on six British swelling soils using modern methods to model the void ratio, e, as a function of the moisture ratio, ϑ. The points on the e–ϑ curve were fitted with a constitutive shrinkage equation using an unbiased least‐squares, curve‐fitting program. The shrinkage curves were then differentiated to obtain their slopes, σ(ϑ), which were used to calculate the overburden potentials, Ω. The slope functions were subsequently differentiated to obtain the curvatures, κ(ϑ), from which the maximum curvature at the wet end was used to separate the structural shrinkage, Sc, from the proportional (unsaturated) shrinkage. At the point of maximum curvature, Sc and the volumetric air content, θac, were calculated and found to correspond closely to those reported previously. Water retention curves were constructed and fitted using the van Genuchten equation, from which the α coefficient appears an important structural parameter. The structural condition of a swelling soil appears to be well described by its air content at the point of maximum curvature, its van Genuchten α coefficient, and a parameter describing the effect of the overburden potential.

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Section: Theory and Methodsmentioning

confidence: 99%

Re‐evaluation of the structural properties of some British swelling soils

Groenevelt¹,

Grant²

2001

European J Soil Science

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“…For most clay and clay soil pastes z r p z z [see, e.g. data from Talsma (1977); van Genuchten (1980) for Bet Netofa clay; Tessier and Pédro (1984); Bruand and Prost (1987); and estimates of z r and z z from Chertkov (2003)]. For such pastes one can consider that already at z .…”

Section: Conditions Of the Negligible Adsorption Contributionmentioning

confidence: 97%

A physically based model for the water retention curve of clay pastes

Chertkov

2004

Journal of Hydrology

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“…Talsma [47] observed the shrinkage behavior of clay paste samples under four loads (Table 1; Fig.16). The samples 2 cm in height and 7 cm in diameter were prepared from Black Earth (NSW, Australia).…”

Section: Talsma's [47] Datamentioning

confidence: 99%

Physical modeling of shrink–swell cycles and cracking in a clayey vadose zone

Chertkov

2015

Geomechanics for Energy and the Environment

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Abstract. Physical understanding of the crack origin and quantitative physical prediction of the crack volume variation far from the clay soil surface are necessary to protect the underlying aquifers from pollutants. The basis of this work is an available physical model for predicting the shrinkage and swelling curves in the maximum water content range (the primary curves) and crack volume variation. The objective of the work is to generalize this model to the conditions of the deep layer of a clayey vadose zone with the overburden pressure, multiple shrinkage-swelling, and variation of water content in a small range. We aim to show that the scanning shrinkage and swelling curves, and steady shrink-swell cycles existing in such conditions, inevitably lead to the occurrence of cracks and a hysteretic crack volume. The generalization is based on the transition to the increasingly complex soil medium from the contributive clay, through the intra-aggregate matrix and aggregated soil with no cracking, to the soil with cracks. The results indicate the single-valued physical links between the scanning shrink-swell cycles and crack volume variation of the four soil media on the one hand, and primary shrinkage and swelling curves of the media on the other hand. The predicted cycles and crack volume hysteresis can be expressed through the physical properties and conditions of the soil at a given depth. The available observations of the cracks and crack volume variation in the clayey vadose zone give strong qualitative experimental evidence in favor of the feasibility of the model. Keywords IntroductionShrinkage cracks close to the soil surface, their origin owing to the vertical water content gradient, and prediction of their volume, width, and spacing are well known [1][2][3][4][5]. Even though these cracks can extend to depths of several meters keeping a micro-width [4], their characteristics cannot explain the origin, volume, and volume variation of the cracks that are directly or indirectly observed at sufficiently large depths of a clayey vadose zone [6][7][8][9][10]. Contrary to the notion about the small permeability of clays, such cracks can essentially increase the hydraulic conductivity of the vadose zone and, correspondingly, transport different contaminant admixtures and solutes to the ground water [6]. Therefore, theoretical estimation of the crack volume, accompanying the natural multifold shrink-swell cycles far from the soil surface, as a function of soil structure and local hydrological conditions, is of theoretical as well as practical interest. In particular, the physical understanding of the origin of such cracks and quantitative physical prediction of the crack volume variation, are important to protect the underlying aquifers from different pollutants.The physical understanding and prediction should take into account the major specific limitations existing in a clay soil at large depths: (i) overburden action at a given depth; (ii) limited and frequently small range of water content variation (compa...

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A note on the shrinkage behaviour of a clay paste under various loads

Cited by 28 publications

References 0 publications

Re‐evaluation of the structural properties of some British swelling soils

Re‐evaluation of the structural properties of some British swelling soils

A physically based model for the water retention curve of clay pastes

Physical modeling of shrink–swell cycles and cracking in a clayey vadose zone

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