Numerical modelling of lumpy clay landfill

Najser, Jan; Maš́ın, David; Boháč, Jan

doi:10.1002/nag.990

Cited by 25 publications

(14 citation statements)

References 44 publications

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“…For example, Cui et al (2002) assumed realistically that the role of macroporosity in swelling of dense compacted soils may be neglected, and developed a global mechanical model based on the microstructural model. Similarly, Koliji et al (2008) and Najser et al (2012) described the behavior of double porosity lumpy soils using a model based on the microstructural behavior, with phenomenological incorporation of the influence of macrostructure.…”

Section: Introductionmentioning

confidence: 99%

Modeling swelling–shrinkage behavior of compacted expansive soils during wetting–drying cycles

Wang¹,

Wei

2015

Can. Geotech. J.

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This paper presents a straightforward approach for modelling volume change behavior of expansive soils during wetting-drying cycles. The swelling-shrinkage strain of expansive soils induced by cyclic wetting and drying was decomposed with distinctive physical background into a reversible component, which shows a synchronous change with the cyclic change of suction, and an irreversible component, which is generated mainly in the early stage of the wetting-drying process. The mechanisms of the two swelling-shrinkage strain components can be well explained through the double-level structure of expansive soils and its evolution with mechanical and hydraulic loading. The reversible component originates from the reversible deformation behavior of aggregates, and primarily depends on current suction or water content. The irreversible component is associated with the irreversible change of macrostructure, reflecting the difference in soil structures at current state and the equilibrium state. A practical constitutive model was proposed for compacted expansive clays from a global and phenomenological perspective. The model parameters can be calibrated with observed macroscopic deformation behavior without measuring microstructural parameters. The performance of the presented model was validated by simulating cyclic suctioncontrolled tests as well as an alternately soaked and dried test with irregular amplitudes of suctions.Key words: expansive soils, volumetric behavior, swelling, shrinkage, model. Résumé :Cet article présente une approche directe pour modéliser les variations de volume de sols expansifs durant des cycles de mouillage-séchage. La déformation causée par le gonflement-retrait des sols expansifs induite par les cycles de mouillageséchage a été décomposée, selon des notions physiques, en une composante réversible qui démontre une variation synchrone avec les variations cycliques de succion, et une composante irréversible qui est générée principalement dans les premières étapes du processus de mouillage-séchage. Les mécanismes des deux composantes de la déformation en gonflement-retrait peuvent être bien expliqués grâce à la structure à deux niveaux des sols expansifs et par l'évolution de cette structure avec les charges mécaniques et hydrauliques. La composante réversible provient de la déformation réversible des agrégats, et dépend principalement de la succion présente et de la teneur en eau. La composante irréversible est associée avec les variations irréversibles de la macrostructure, reflétant les différences dans les structures du sol à l'état présent et à l'état d'équilibre. Un modèle constitutif pratique est proposé pour les argiles expansives compactées basé sur une perspective globale et phénomé-nologique. Les paramètres du modèle peuvent être calibrés avec les déformations macroscopiques observées sans mesurer les paramètres microstructuraux. La performance du modèle présenté a été validée en simulant des essais de succion cyclique contrôlés de même d'avec un essai alternant le mouillage...

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Section: Introductionmentioning

confidence: 99%

Modeling swelling–shrinkage behavior of compacted expansive soils during wetting–drying cycles

Wang¹,

Wei

2015

Can. Geotech. J.

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“…The overall effective mean stress can also be calculated from the volumeaveraged stresses of the constituents with the volume fraction according to Eq. (6). The overall strain is defined similarly to those of its constituents:…”

Section: Verification Of the Homogenization Law Using The Finite Elemmentioning

confidence: 99%

Analysis of the compression behavior of artificial lumpy composite materials

Shi

2016

Int. J. Numer. Anal. Meth. Geomech.

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Summary The landfills are dumped without any compaction and have a relatively open structure, which is similar to that of the granular materials. However, the original dumped material might be gradually transformed into a lumpy composite structure because of the influence of the climate. As a result, the lumps are randomly distributed in the reconstituted soil. In the presented study, the compression behavior of the lumpy composite soils was analyzed within the homogenization framework. Firstly, the volume of the composite soil was divided into four individual components. The inter‐lump porosity was introduced to account for the evolution of the volume fractions of the constituents, and it was formulated as a function of the overall porosity and those of its constituents. A homogenization law was then proposed based on the analysis of the lumpy structure together with a numerical method, which gives a relationship for tangent stiffnesses of the lumpy soil and its constituents. Finally, a simple compression model was proposed for the composite lumpy material, which incorporates both the influence of the soil structure and the volume fraction change of the reconstituted soil. The predictions of the model were validated against the test results, and the stress distribution within the lumpy composite was assessed. Copyright © 2016 John Wiley & Sons, Ltd.

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“…After several years from filling, mainly due to the influence of climate, gravitational effect and precipitation, the originally high interlump porosity clays in landfills tend to become relatively homogeneous soils (Figure 1(b)). However, even more than 10 years after filling, their corresponding double porosity still remains (Masin et al, 2005;Najser et al, 2010Najser et al, , 2012.…”

Section: Introductionmentioning

confidence: 96%

“…In many parts of the world, the large-scaleopencast coal mining has resulted in depositing the clayey overburden in non-engineered landfills (Herbstova and Herle, 2009;Najser et al, 2012). These kinds of landfills usually reach depths of several tens of metres.…”

Section: Introductionmentioning

confidence: 99%

Laboratory investigation of artificial lumpy materials

Shi

2014

Engineering Geology

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Numerical modelling of lumpy clay landfill

Cited by 25 publications

References 44 publications

Modeling swelling–shrinkage behavior of compacted expansive soils during wetting–drying cycles

Modeling swelling–shrinkage behavior of compacted expansive soils during wetting–drying cycles

Analysis of the compression behavior of artificial lumpy composite materials

Laboratory investigation of artificial lumpy materials

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