scholarly journals Dependence of the water retention curve of snow on snow characteristics

2012 ◽  
Vol 53 (61) ◽  
pp. 6-12 ◽  
Author(s):  
Satoru Yamaguchi ◽  
Kunio Watanabe ◽  
Takafumi Katsushima ◽  
Atsushi Sato ◽  
Toshiro Kumakura
Keyword(s):  
Grain Size ◽  
Snow Cover ◽  
Water Retention ◽  
Water Movement ◽  
Column Experiment ◽  
Water Retention Curve ◽  
Dry Density ◽  
Soil Physics ◽  
Retention Curve ◽  
Physics Model

AbstractThe water retention curve (WRC), which shows the relationship between the volumetric liquid water content,θv, and suction,h, is a fundamental part of the characterization of hydraulic properties. Therefore, the formulation of the WRC as a function of snow characteristics is essential for establishing a model of water movement through the snow cover. In this study, we measured the WRC of several snow samples, which had different characteristics (grain size, bulk dry density and grain type), using a gravity drainage column experiment and then analysed these data using the Van Genuchten soil physics model (VG model). The shape of the WRC depended strongly on both the sample grain size,d, and bulk dry density,ρ. Therefore, we introduced the parameterρ/dto model the WRC of snow. The relationships between the parametersαandnof the VG model andρ/dchange with grain type. For melt forms,α, which is related to the inverse value of the air-entry suction, increases quickly asρ/ddecreases, whereasn, which is related to the gradient ofθvvsh, increases withρ/d. Conversely, neither of these parameters of the VG model for rounded grains showed obvious dependence onρ/d. These results suggest that water movement through snow cover can be modelled using grain size, bulk dry density and grain type based on the soil physics model.

scholarly journals Determination of soil-water retention curve: an artificial intelligence-based approach

2020 ◽  
Vol 195 ◽  
pp. 02010
Author(s):  
Ehsan Nikooee ◽  
Rasoul Mirghafari ◽  
Ghassem Habibagahi ◽  
Alireza Ghadamgahi Khorassani ◽  
Amir Mohammad Nouri
Keyword(s):  
Grain Size ◽  
Water Retention ◽  
Water Retention Curve ◽  
Silty Clay ◽  
Clay Loam ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Retention Curve ◽  
Physically Based ◽  
Physically Based Models

Soil Water Retention Curve (SWRC) is a fundamental relationship in unsaturated soil mechanics, knowledge of which is essential for determining major mechanical and hydraulic properties of unsaturated soils. There are several empirical, semi-empirical and physically-based models which have been proposed to date for estimating SWRC. While the physically-based models which employ the basic soil characteristics such as grain-size and pore-size distributions are regarded superior to purely empirical models, their Achilles’ heel is the several simplifying assumptions based on which these models are constructed, thereby, restricting their applications and influencing their accuracy. Given the complexity of the soil porous structure, one may resort to the new inference techniques rather than mechanistic modelling to find the relationship among soil physical characteristics and the retention properties. Therefore, an alternative approach to purely empirical relationships as well as physically-based and conceptual models for determining SWRC is the use of Artificial Intelligence (AI) based techniques to acquire a relationship for SWRC based on the soil basic properties, especially grain size distribution and porosity. Among AI-based methods, Multi-Gene Genetic Programming (MGGP), often used to establish a close form equation for a complex physical system, offers a suitable alternative to the current approaches. In this study, a database compromising of 437 soils (containing various soil types, namely, sand, clay, silt, loam, silt loam, clay loam, sandy loam, sandy clay loam, silty clay loam, silty clay, and loamy sand soils) was used along with MGGP to establish a relationship among suction, saturation, porosity and grain size distribution. The proposed equation had a reasonable agreement with the experimental data compared to the other grain-based and physically-based models.

scholarly journals Relating Hydraulic Conductivity Curve to Soil-Water Retention Curve Using a Fractal Model

Mathematics ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 2201
Author(s):  
Carlos Fuentes ◽  
Carlos Chávez ◽  
Fernando Brambila
Keyword(s):  
Hydraulic Conductivity ◽  
Fractal Geometry ◽  
Water Retention ◽  
Water Movement ◽  
Darcy Law ◽  
Water Retention Curve ◽  
Hydrodynamic Characteristics ◽  
Soil Pressure ◽  
Retention Curve ◽  
Conductivity Curve

In the study of water transference in soil according to Darcy law, the knowledge of hydrodynamic characteristics, formed by the water retention curve θ(ψ), and the hydraulic conductivity curve K(ψ) are of great importance. The first one relates the water volumetric content (θ) with the water-soil pressure (ψ); the second one, the hydraulic conductivity (K) with the water-soil pressure. The objective of this work is to establish relationships between both curves using concepts of probability theory and fractal geometry in order to reduce the number of unknown functions. The introduction of four definitions used at the literature of the pore effective radius that is involve in the general model has permitted to establish four new specials models to predict the relative hydraulic conductivity. Some additional considerations related to the definitions of flow effective area and the tortuosity factor have allow us to deduce four classical models that are extensively used in different studies. In particular, we have given some interpretations of its empirical parameters in the fractal geometry context. The resulting functions for hydrodynamic characteristics can be utilized in many studies of water movement in the soil.

A model to predict the water retention curve from basic geotechnical properties

2003 ◽  
Vol 40 (6) ◽  
pp. 1104-1122 ◽  
Author(s):  
M Aubertin ◽  
M Mbonimpa ◽  
B Bussière ◽  
R P Chapuis
Keyword(s):  
Grain Size ◽  
Unsaturated Soils ◽  
Water Retention ◽  
Liquid Limit ◽  
Geotechnical Properties ◽  
Degree Of Saturation ◽  
Water Retention Curve ◽  
Adhesion Forces ◽  
Retention Curve ◽  
Fine Grained

The water retention curve (WRC) has become a key material function to define the unsaturated behavior of soils and other particulate media. In many instances, it can be useful to have an estimate of the WRC early in a project, when little or no test results are available. Predictive models, based on easy to obtain geotechnical properties, can also be employed to evaluate how changing parameters (e.g., porosity or grain size) affect the WRC. In this paper, the authors present a general set of equations developed for predicting the relationship between volumetric water content, θ, (or the corresponding degree of saturation, Sr) and suction, ψ. The proposed model assumes that water retention results from the combined effect of capillary and adhesion forces. The complete set of equations is given together with complementary relationships developed for specific applications on granular materials and on fine-grained soils. It is shown that the model provides a simple and practical means to estimate the water retention curve from basic geotechnical properties. A discussion follows on the capabilities and limitations of the model, and on additional tools developed to complement its use. Key words: water retention curve, unsaturated soils, prediction, porosity, grain size, liquid limit.

INFLUENCE OF SOIL MATRIX ON SOIL-WATER RETENTION CURVE AND HYDRAULIC CHARACTERISTICS

2017 ◽  
Vol 16 (4) ◽  
pp. 869-877
Author(s):  
Vasile Lucian Pavel ◽  
Florian Statescu ◽  
Dorin Cotiu.ca-Zauca ◽  
Gabriela Biali ◽  
Paula Cojocaru
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Water Retention Curve ◽  
Hydraulic Characteristics ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Soil Matrix ◽  
Retention Curve
Sign in / Sign up

Export Citation Format

Share Document