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Desiccation cracking of soils Herv Peron Lyesse Laloui Tomasz Hueckel Liang Bo Hu Ecole Polytechnique F d rale de Lausanne EPFL Laboratory of Soil Mechanics Station 18 CH 1015 Lausanne Switzerland herve peron epfl ch Duke University Department of Civil and Environmental Engineering Durham NC 27708 U S A ABSTRACT The scope of this paper is to present the global mechanisms of soil desiccation including drying shrinkage and cracking The paper first reviews the basic processes that are beneath the word desiccation Then the results of an experimental study of desiccation are presented in which strains suction water content degree of saturation and crack geometry are investigated The results show that cracking initiates close to the onset of de saturation Insights into the micro scale are proposed to explain this observation A scenario for the processes leading to crack initiation is further established in terms of the macroscopic variables an assessment of the stress building up is proposed until a critical point at which the tensile strength is met Desiccation crack pattern formation is finally discussed R SUM Le but de cet article est de pr senter l ensemble des m canismes de la dessiccation des sols comprenant le retrait de s chage et la fissuration La nature de ces derniers processus dans les sols est tout d abord d finie Les r sultats d une tude exp rimentale de la dessiccation qui consiste en une investigation de l volution des d formations de la succion de la teneur en eau du degr de saturation et de la g om trie des fissures sont ensuite expos s Les r sultats montrent que la fissuration commence un moment proche du d but de la d saturation et de la valeur d entr e d air Cette observation est interpr t e l chelle microscopique Un sc nario pour les processus menant l initiation de la fissuration est tabli en termes de variables macroscopiques une valuation du d veloppement des contraintes jusqu un crit re macroscopique d initiation des fissures est propos e La formation des formes de fissures est finalement discut e KEYWORDS drying shrinkage cracking degree of saturation air entry value stresses retrait de s chage fissuration degr de saturation valeur d entr e d air contraintes MOTS CL S DOI 10 3166 EJECE 13 869 888 2009 Lavoisier Paris EJECE 13 2009 Failure in multiphase geomaterials pages 869 to 888 870 EJECE 13 2009 Failure in multiphase geomaterials 1 Introduction Drying of soils and the ensuing cracking are a crucial issue in geo environmental engineering Drying fractures strongly affect permeability and may compromise the integrity of structures such as clay buffers for nuclear waste isolation In addition cracking is the cause of substantial damage in foundation supported structures Compressibility increases substantially while the rate of consolidation decreases with the appearance of desiccation cracks Morris et al 1992 Cracks are also a possible precursor for inception of a failure surface at the top of dams and embankments Assessment

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