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An experimental method to study the drying-wetting behaviour of a sand
Publikationstyp
Conference Paper
Date Issued
2016-10
Sprache
English
Author(s)
Institut
TORE-URI
Start Page
211
End Page
216
Citation
Asia-Pacific Conference on Unsaturated Soils: 211-216 (2016-10)
Contribution to Conference
The Soil-Water Characteristic Curve (SWCC) is a basic function of unsaturated soil behaviour. It is essential for the understanding of effective stress in unsaturated soils and for unsaturated flow behaviour. Therefore, the experimental determination of the SWCC is an important issue of research. This task is often time consuming and in many cases, using standard test methods, only the main branches for either drying or wetting can be determined. For some types of soil however, the SWCC encounters rigorous hysteretic behaviour, which is of importance when cyclic flow occurs. Therefore, also test data on hydraulic hysteresis and the scanning curves is needed. In this paper an experimental method is presented, which allows to determine the SWCC of a coarse grained soil in a transient way, taking hysteresis into account. The method applies a flow of water volume to a small soil specimen, subjected to atmospheric air pressure at the top. This allows to prescribe monotonic or cyclic drying or wetting paths in the degree of saturation-suction space. While the degree of saturation can be calculated from the prescribed water outflow, the soil suction is simultaneously measured on top of the specimen using a miniature tensiometer.As a result of the test the SWCC can be obtained as well as different scanning paths and their slope δSr/δs, which is especially important for the development of hydraulic hysteresis models.