Determination of soil-water characteristic curves

Soils from arid and semi-arid regions, compacted soils and residual soils are examples of unsaturated soils encountered in engineering practice. Unsaturated soils have negative pore-water pressures or matric suction when referenced to pore-air pressure. By the use of a miniature tensiometer for measurement of high matric suction, the matric suction of the soil could be measured directly. In this project, a clayey sand sample and a residual soil sample were prepared by specimens of 50mm diameter but of different height (20mm, 40mm, and 80mm) were trimmed from the samples to determine the soil-water characteristic curves. Drying soil-water characteristic curve and a partial wetting soil-water characteristic curve were obtained. The pressure plate test results showed that specimens of different height produce similar soil-water characteristic curves. The time for the specimens to reach equilibrium weight/loss gain were similar irrespective of specimen height. Measurement of matric suction of the pressure plate specimen using the high suction tensiometer showed that the specimen achieved the applied matric suction in a shorter time than indicated by the weight loss/gain curve.Bachelor of Engineerin