Modeling of Hydrophysical Properties of the Soil as Capillary-Porous Media and Improvement of Mualem-Van Genuchten Method as a Part of Foundation Arrangement Research

Vitaly Terleev,Vladimir Badenko,Olga Skvortsova,Aleksandr Nikonorov,Wilfried Mirschel,Inna Guseva,Yulia Volkova,Sergey Pavlov

doi:10.1155/2016/8176728

Abstract

Within the concepts about the capillarity and the lognormal distribution of effective pore radii, a theoretical justification for function of differential water capacity and its antiderivative (function of water-retention capacity in form of a dependence of the soil volumetric water content on capillary pressure of the soil moisture) is presented. Using these functions, the ratio of soil hydraulic conductivity function to the filter coefficient is calculated. Approximations to functions describing the water-retention capacity and relative hydraulic conductivity of the soil have been suggested. Parameters of these functions have been interpreted and estimated with applying the physical and statistical indices of the soil.

Highlights

In laboratories usually do not measure the differential water capacity (DWC) function μ = μ(ψ) but its antiderivativewater sorption equilibrium isotherm as a dependence of the volumetric soil moisture θ on capillary pressure of the soil moisture ψ
Calculating the values of DWC is usually limited to interpolating the measured water-retention capacity (WRC) data and to selection of the approximating function, which is used in the computation by the formula μ = dθ/dψ
Formulas (13b) and (16b) have been used to depict curves (1) and (2), which represent the approximation to WRC and relative hydraulic conductivity function (HCF)

Summary

Introduction

In laboratories usually do not measure the differential water capacity (DWC) function μ = μ(ψ) but its antiderivativewater sorption equilibrium isotherm as a dependence of the volumetric soil moisture θ (cm3⋅cm−3) on capillary pressure of the soil moisture ψ (cm H2O). The dependence θ(ψ) is an indicator of water-retention capacity (WRC) of soil. Calculating the values of DWC is usually limited to interpolating the measured WRC data and to selection of the approximating function, which is used in the computation by the formula μ = dθ/dψ. The degree function was previously widely used for the interpolation of modified WRC points for the subsequent calculation of the DWC values. There are some positive examples of the use of WRC approximations, which include the model:

Objectives

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Conclusion