Soil-water characteristic curve and permeability function for unsaturated cracked soil

Cracks are widely present in natural and engineered soils. As water infiltration into a cracked soil often starts from unsaturated conditions, the soil-water characteristic curve (SWCC) and permeability function for the cracked soil are required when conducting seepage analysis. This paper presents a method to predict the SWCC and permeability function for cracked soil considering crack volume changes during drying-wetting processes. The cracked soil is viewed as an over- lapping continuum of a crack network system and a soil matrix system. The pore-size distributions for the two pore systems at a particular state can be determined and used to estimate the SWCCs and permeability functions. The estimated SWCCs and permeability functions for the two pore systems can be combined to give the SWCC and the permeability function for the cracked soil at that state. Then, the SWCC and permeability function for the cracked soil at different states along a crack development path can be obtained and combined to give the SWCC or permeability function for the cracked soil consider- ing crack volume changes. Examples are presented to illustrate the prediction of the SWCCs and permeability functions for a cracked soil along five crack development paths. Resume : Les sols naturels et d'ingenierie comportent de nombreuses fissures. Puisque l'infiltration de l'eau dans un sol fis- sure debute normalement a l'etat non sature, la courbe de retention d'eau (CRE) et la fonction de permeabilite du sol fissure sont necessaires pour effectuer une analyse d'infiltration. Cet article presente une methode pour predire la CRE et la fonc- tion de permeabilite pour un sol fissure en considerant les changements de volume des fissures durant les processus de mouillage-drainage. Le sol fissure est decrit comme un systeme continu et superpose compose d'un reseau de fissures et d'une matrice de sol. La distribution de la taille des pores pour les deux systemes de pores a un etat specifique peut etre de- termine et utilise pour estimer les CRE et les fonctions de permeabilite. Les CRE et les fonctions de permeabilites estimees pour les deux systemes de pores peuvent etre combinees pour donner la CRE et la fonction de permeabilite pour le sol fis- sure dans cet etat specifique. Ensuite, la CRE et la fonction de permeabilite du sol fissure a differents etats au cours du de- veloppement de fissures peut etre obtenues et combinees pour donner la CRE ou la fonction de permeabilite pour le sol fissure en considerant les variations de volume des fissures. Des exemples sont presentes afin d'illustrer la prediction des CRE et des fonctions de permeabilite pour un sol fissure selon cinq chemins de developpement de fissures. Mots-cles : sol fissure, fissures, fractures, conductivite hydraulique, fonction de permeabilite, infiltration, courbes de reten- tion d'eau, sol non sature, courbes caracteristiques sol-eau. (Traduit par la Redaction)

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