considering soil properties, moisture is of central significance, affecting its physical characteristics and behavior. that is why, determining soil water volume and the way it moves through soil is of importance. the most basic parameter in water movement is hydraulic conductivity in saturated and unsaturated conditions.the present study, incorporating campbell method of soil characteristic cu...

A new simple shear apparatus is fabricated which is capable of applying monotonic and cyclic load on soil specimens. A series of tests was conducted to study the pore pressures (or suction), volume change, and shear behavior of the soil samples with anisotropic consolidation pressure. The simple shear apparatus is capable of controlling as well as measuring pore-air and pore-water pressure in t...

This paper presents an overview of elasto-plastic modelling of unsaturated soils. Alternative stress and strain variables that have been used in constitutive models for unsaturated soils are discussed. The use of an effective stress equation may simplify constitutive relations, but often result in a stress space that depends on the material state. In this case, the constitutive behaviour is emb...

The Soil-Water Characteristic Curve (SWCC) is an important soil function relating the water content of a soil to soil suction. Many unsaturated soil properties (or soil property functions) can be related to the water content versus suction relationship of a soil. Hydraulic conductivity, shear strength, chemical diffusivity, water storage, unfrozen volumetric water content, specific heat, and th...

the majority of hydraulic processes under a natural condition in a field are carried out under unsaturated flow conditions. the soil moisture retention curve (smrc) is the most important hydraulic characteristic of an unsaturated soil whose knowledge is of prime importance in soil-water studies such as soil conservation, soil erosion, land evaluation, soil reclamation, and water resources manag...

The Richards equation is widely used as a model for the flow of water in unsaturated soils. For modelling one-dimensional flow in a homogeneous soil, this equation can be cast in the form of a specific nonlinear partial differential equation with a time derivative and one spatial derivative. This paper is a survey of recent progress in the pure mathematical analysis of this last equation. The e...

A complete thermo-hydro-mechanical model is presented to tackle the complex coupling problems encountered in clay barriers. A detailed formulation coupling the heat, moisture (liquid water and water vapour) and, air transfer in a deformable unsaturated soil is given. The formulation of the AlonsoGens’s mechanical model for unsaturated soil is also incorporated. The sensitivity to some parameter...

A thermodynamically consistent extension of the constitutive equations of saturated soils to unsaturated conditions is often worked out through the use of a unique ’effective’ interstitial pressure, accounting equivalently for the pressures of the saturating fluids acting separately on the internal solid walls of the pore network. The natural candidate for this effective interstitial pressure i...

The water flow in unsaturated soils is governed by Richards equation, a nonlinear parabolic partial differential equation. In a layered unsaturated soil, enforcing the continuity of both pressure head and flux across the interface of distinct soil materials leads to a non-linear interface equation. This interface equation may exhibit multiple solutions. Using different averaging methods for cel...

An iterative geostatistical inverse approach is developed to estimate conditional effective unsaturated hydraulic conductivity parameters, soil-water pressure head, and degree of saturation in heterogeneous vadose zones. This approach is similar to the classical cokriging technique, and it uses a linear estimator that depends on covariances and cross covariances of unsaturated hydraulic paramet...