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Performances of two instrumented laboratory models for the study of rainfall infiltration into unsaturated soil

M. L., Lee and A., Kassim and N. , Gofar (2011) Performances of two instrumented laboratory models for the study of rainfall infiltration into unsaturated soil. Engineering Geology Journal, 117 . 78–89. ISSN 0013-7952

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Official URL: http://dx.doi.org/10.1016/j.enggeo.2010.10.007

Abstract

Rainfall infiltration and suction variation in unsaturated soils must be taken into consideration in the analysis of most slope stability problems, particularly in the tropical regions where the annual precipitation is high. The process of rainfall in?ltration into unsaturated soils is an extremely complex problem attributed to the non-linearity of the hydraulic property functions of the unsaturated soils. This paper describes in detail two instrumented laboratory models, i.e. one-dimensional soil column, and two-dimensional slope model used to provide experimental evidences for the transient suction variations in the unsaturated soils under certain rainfall conditions. The performances of the laboratory models were tested on four typical types of residual soils, i.e. sand-gravel, silty gravel, sandy silt, and silt (kaolin), and a two-layered soil system, i.e. sandy silt underlain by silty gravel. The results showed that the suction distributions for the single-layered homogeneous soils obtained from the simpler one-dimensional soil column were almost identical to that of two-dimensional slope model. However, the two-dimensional slope model should be employed for the two-layered soil system because of the dominant effect of the lateral ?ow mechanism. The capillary barrier effect was observed when a less permeable soil layer was underlain by a more permeable soil layer. The minimum suction value in soil is governed by the rainfall intensity, rainfall duration, and the saturated permeability of soil. The in?ltration rate of the ?ne-grained soils that subjected to shrink and crack was independent of the soil permeability, but was signi?cantly governed by the preferential ?ows developed in the soils.

Item Type:Article
Uncontrolled Keywords:rainfall infiltration,unsaturated soil, laboratory model, slope stability, suction distribution
Subjects:T Technology > TA Engineering (General). Civil engineering (General)
Divisions:Civil Engineering
ID Code:25968
Deposited By: Liza Porijo
Deposited On:21 Jun 2012 08:12
Last Modified:27 Feb 2013 01:27

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