thumbnail

Hysteresis and uncertainty in soil water-retention curve parameters

Journal of Geotechnical and Geoenvironmental Engineering

By:
, ,
DOI: 10.1061/(ASCE)GT.1943-5606.0001071

Links

Abstract

Accurate estimates of soil hydraulic parameters representing wetting and drying paths are required for predicting hydraulic and mechanical responses in a large number of applications. A comprehensive suite of laboratory experiments was conducted to measure hysteretic soil-water characteristic curves (SWCCs) representing a wide range of soil types. Results were used to quantitatively assess differences and uncertainty in three simplifications frequently adopted to estimate wetting-path SWCC parameters from more easily measured drying curves. They are the following: (1) αw=2αd, (2) nw=nd, and (3) θwsds, where α, n, and θs are fitting parameters entering van Genuchten’s commonly adopted SWCC model, and the superscripts w and d indicate wetting and drying paths, respectively. The average ratio αw/αd for the data set was 2.24±1.25. Nominally cohesive soils had a lower αwd ratio (1.73±0.94) than nominally cohesionless soils (3.14±1.27). The average nw/nd ratio was 1.01±0.11 with no significant dependency on soil type, thus confirming the nw=nd simplification for a wider range of soil types than previously available. Water content at zero suction during wetting (θws) was consistently less than during drying (θds) owing to air entrapment. The θwsds ratio averaged 0.85±0.10 and was comparable for nominally cohesive (0.87±0.11) and cohesionless (0.81±0.08) soils. Regression statistics are provided to quantitatively account for uncertainty in estimating hysteretic retention curves. Practical consequences are demonstrated for two case studies.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Hysteresis and uncertainty in soil water-retention curve parameters
Series title:
Journal of Geotechnical and Geoenvironmental Engineering
DOI:
10.1061/(ASCE)GT.1943-5606.0001071
Volume
140
Issue:
4
Year Published:
2014
Language:
English
Publisher:
American Society of Civil Engineers
Contributing office(s):
Geologic Hazards Science Center
Description:
11 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Geotechnical and Geoenvironmental Engineering
Number of Pages:
11