A Simple Device to Measure Soil Water Retention Curve

The soil water retention curve is very critical in the assessment of unsaturated soil behavior. In the past, with the help of the axis translation technique, the pressure plate method was usually used to measure the soil water retention curve. However, this test was very time-consuming and required using specimens with the same loading history which was difficult to achieve. In this study, a simple device is proposed to measure the water retention curve of poorly graded sand with silt through a discrete evaporation test in which the soil suction and water content are measured using a high-capacity tensiometer and a digital balance, respectively. Measurement of representative soil suction was achieved through sealing the specimen to allow the water redistribution in the soil after a certain time of free evaporation. Results from this evaporation test indicate that the time required for the soil water retention curve can be significantly reduced from weeks to 1-2 days when compared with the conventional pressure plate method