Measurement of soil-water characteristic curves of quasi-saturated soils

摘要

Important geotechnical structures involve cohesive soil compacted either around or on the wet side of optimum water content. In general, at the corresponding saturation values, water component in soil voids is continuous but the air phase is not. The soil with entrapped air may be assumed to be in a state termed as "quasi-saturated". The soil-water characteristic curve is often used to estimate unsaturated soil property functions. Since the measurement of pore air pressure in an occluded sample is extremely difficult, the data for the soil-water characteristic curve of quasi-saturated soils is not well defined. A simple experimental procedure for rapid measurement of continuous soil-water characteristics curves of quasi-saturated soils is described in this paper. The apparatus, testing procedures and results are presented and discussed. Data from the test results are used to validate a theoretical soil-water characteristic function involving discontinuous air phase derived by using the occluded state theory proposed by Schuurman (1966).