This paper examines the current procedure for determining the soil water characteristic curve swcc model with a particular focus on its application to slope stability analysis under transient. In recent years, the soil water characteristic curve swcc has become an. If the tension is expressed as the logarithmic value of cm water, the graph is referred to as a pfcurve. Test study on soilwater characteristic curve of bentonitesand. The swc is an important soil property related to pore space distribution sizes, interconnectedness, which is strongly. Role of the soil water characteristic curve in unsaturated. The soil water characteristic curves of statically compacted specimens for three different finegrained soils with varying percentages of clay were measured using the centrifuge for a suction. Nature of soil water characteristics curves swcc for soils from anbar governorate. The definition for the vadose zone is the same as that commonly used for the unsaturated soil zone in unsaturated soil mechanics. The equation provides a good fit for sand, silt, and clay soils over the entire suction range from 0 to 10pa. Soil water characteristic curve of an unsaturated soil under low. This is an important definition to retain because of the manner in which the soilwater characteristic curve is measured in the laboratory and used in engineering practice. Statistical assessment of soilwater characteristic curve. A national catalog of subgrade soil water characteristic curve swcc default inputs and selected soil properties for use with the mepdg.
The soil water characteristic curve can be used to estimate various parameters used to describe unsaturated soil behaviour. One of the main unsaturated soil parameters required for modeling is the soil water characteristic curve swcc. Prediction of the soil water characteristic curve from. This thesis evaluates whether unsaturated soil hydraulic functions estimated by a number of published techniques can be used to predict insitu pore pressure development in unsaturated soils.
Water retention activity in soils which is used to predict the stability or seepage problems in the ground is one of the key features in unsaturated. This paper presents a method of estimating the soil water characteristic curve swcc of coarsegrained soils using parameters derived from the grainsize distribution curve and volume mass. In this paper, test studies on soilwater characteristic curve swcc of bentonitesand mixtures are presented. Soilwater characteristic curve modeling at low water content. For each soil case study, the characteristic curve is obtained using the filter paper. A nonlinear, leastsquares computer program is used to determine the bestfit parameters for experimental data presented in the literature. Optimization of soilwater characteristic curve data optimization techniques are used to obtain the bestfit pa. Prediction of the soil water characteristic curve from grain size distribution allows for a inexpensive description of the behavior of. Evaluation of soil water characteristic curves of sandclay mixtures. Pdf soilwater characteristic curves and dual porosity. The objective of this study is to estimate multiplecycles of the soilwater characteristic curve swcc using an innovative volumetric pressure. Pdf soil water characteristic curves and dual porosity. The incremental soil water characteristic curves are then summed to produce a final soil water characteristic curve. During laboratory assessment of the soil water characteristic curve swcc, determining.
Equations for the soilwater characteristiccurve soilvision. This method is similar to that proposed by fredlund et al. A methodological framework to determine optimum durations for the. Simulation of the soilwater characteristic curve using. The soil water characteristic curve the soil water characteristic swc curve describes the functional relationships between soil water content v or m and matric potential under equilibrium conditions.
The pump characteristic curves ae for a range of pumps are given in the figure 6. A packing porosity and soil water characteristic curve is assumed for each group of particles. A national catalog of subgrade soil water characteristic. Pdf equations for the soilwater characteristiccurve. Pdf soil water characteristic curves swccs of mining sand. Estimation of soilwater characteristic curves in multiplecycles. The soil water characteristic introduction and measurement. Pdf nature of soilwater characteristics curves swcc. Review of soil water retention characteristic swrc. A general equation for the soil water characteristic curve is proposed. The mathematical correction procedures are applied to all of the proposed soilwater characteristic curve models.
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