A Dynamic Method for Determining the Soil Water Characteristic Curve for Coarse-Grained Soils

摘要

The air-entry suction is an extremely importnat parameter in the water characteristic curve, but is difficult to identify when using conventional static methods such as the pressure plate apparatus. In the dynamic method described herein, instantaneous measurement of matric suction and water content are acquired from a soil specimen undergoing a slow drying cycle with the aid of a tensiometer and a soil moistue probe, respectively. The method offers a quaick and reliable way of quantifying the drying soil-water characteristic curve (SWCC) for matric suctions of up to 80 kPa. The large number of data points acquired make it easy to obtain an accurate estimate of the air-entry suction. It is particularly effective for soils ranging from medium sands to sandy silts where a nearly continuous SWCC is provided.