Field soil-water characteristics and its engineering implication

Abstract

In order to study soil-water characteristics of unsaturated soil slope, moisture probe and tensiometers are installed simultaneously for the soils at depths of 1, 2, 3 and 4 m at the crest of a cut slope in Hong Kong. Based on the field monitored results of volumetric water content and matric suction, field soil-water characteristic curves for the soils at different depths at the crest are determined. Compared with the obvious hysteresis of laboratory soil-water characteristic curves, the field soil-water characteristic curve shows negligible hysteresis. The negligible hysteresis may be attributed to the non-equilibrium effect during the heavy rainfall or the different measurements of volumetric water contents and matric suctions in the field and laboratory. Furthermore, the engineering implication of the field soil-water characteristic curve is also discussed in this paper.