Probabilistic Analysis of Soil-Water Characteristic Curves |
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Authors: | Kok-Kwang Phoon Anastasia Santoso Ser-Tong Quek |
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Affiliation: | 1Professor, Dept. of Civil Engineering, National Univ. of Singapore, Blk E1A, #07-03, 1 Engineering Dr. 2, Singapore 117576, Singapore. E-mail: cvepkk@nus.edu.sg 2Research Scholar, Dept. of Civil Engineering, National Univ. of Singapore, Blk E1A, #07-03, 1 Engineering Dr. 2, Singapore 117576, Singapore (corresponding author). E-mail: g0600999@nus.edu.sg 3Professor, Dept. of Civil Engineering, National Univ. of Singapore, Blk E1A, #07-03, 1 Engineering Dr. 2, Singapore 117576, Singapore. E-mail: cveqst@nus.edu.sg
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Abstract: | Direct measurement of the soil-water characteristic curve (SWCC) is costly and time consuming. A first-order estimate from statistical generalization of experimental data belonging to soils with similar textural and structural properties is useful. A simple approach is to fit the data with a nonlinear function and to construct an appropriate probability model of the curve-fitting parameters. This approach is illustrated using sandy clay loam, loam, loamy sand, clay, and silty clay data in Unsaturated Soil Database. This paper demonstrates that a lognormal random vector is suitable to model the curve-fitting parameters of the SWCC. Other probability models using normal, gamma, Johnson, and other distributions do not provide better fit than the proposed lognormal model. The engineering impact of adopting a probabilistic SWCC is briefly discussed by studying the uncertainty of unsaturated shear strength due to the uncertainty of SWCC. |
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Keywords: | Unsaturated soils Soil water Probability Correlation Shear strength Uncertainty principles |
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