Steady-state and transient one-dimensional unsaturated flow in vertically stratified porous media are examined. Saturated hydraulic conductivity and the alpha parameter of the exponential hydraulic conductivity function were assumed to vary from soil layer to soil layer. The use of effective unsaturated hydraulic conductivity to compute matric potential in the soil profile is demonstrated. Resu...

The mechanical behaviour of unsaturated soils is one of the challenging topics in the field of geotechnical engineering. The use of finite element technique is considered as a promising method to solve settlement and heave problems, as associated with unsaturated soil. Nevertheless, the success of the numerical analysis is strongly dependent on constitutive model being used. The well-known Barc...

In order to obtain the soil water retention curve of an unsaturated soil which is defined as the relationship between water content and suction, extensive laboratory tests are essential. These laboratory tests are usually costly and time consuming. Moreover, for most practical problems, it has been found that approximate unsaturated soil properties are adequate for analysis. Thus, empirical pro...

Constitutive equations of unsaturated soils are often derived in a thermodynamically consistent framework through the use a unique ’effective’ interstitial pressure. This later is naturally chosen as the space averaged interstitial pressure. However, experimental observations have revealed that two stress state variables were needed to describe the stressstrain-strength behaviour of unsaturated...

mathematical simulation of flow toward drains is an important and indispensable stage in drainage design and management. many related models have been developed, but most of them simulate the saturated flow toward drains without a due consideration of the unsaturated zone. in this study, the two dimensional differential equation governing saturated and unsaturated flow in porous media is numeri...

By employing chemical and isotopic tracers ((15)N and (18)O in NO(3)(-)), we investigated the main processes controlling nitrate distribution in the unsaturated zone and aquifer. Soil water was extracted from two soil cores drilled in a typical agricultural cropping area of the North China Plain (NCP), where groundwater was also sampled. The results indicate that evaporation and denitrification...

This work presents a rigorous numerical validation of analytical stochastic models of steady state unsaturated flow in heterogeneous porous media. It also provides a crucial link between stochastic theory based on simplifying assumptions and empirical field and simulation evidence of variably saturated flow in actual or realistic hypothetical heterogeneous porous media. Statistical properties o...

The true efficacy of a programme of agricultural mitigation measures within a catchment to improve water quality can be determined only after a certain hydrologic time lag period (subsequent to implementation) has elapsed. As the biophysical response to policy is not synchronous, accurate estimates of total time lag (unsaturated and saturated) become critical to manage the expectations of polic...

Unsaturated hydraulic conductivity (K) is a measurement of soil water-retaining ability in unsaturated soil. The properties are necessary to predict the movement water current study aims create an alternative experimental device estimate theKusing moisturesensors. set up was designed and fabricated order measure volumetric content using GS3 (Campbell) sensors at different heights. data obtained...

The identification of freezing-thawing soil hydraulic properties is the basis and key problem of studying soil water movement. Current identifying methods of the properties have many limitations, such as big error, high uncertainty and low operability. Thus, the identifying method of freezingthawing soil hydraulic properties was researched in the research. The estimating parameters of soil free...