Measurement of Soil-Water Characteristic Curve with a continuous pressurization method

In order to measure the Soil-Water Characteristic Curve (SWCC), a continuous pressurization method is presented (Hatakeyama et al., 2015). In this method, the air pressure for the specimen is continuously increased for an air pressure chamber, in which a small pore water measurement devise is equipped inside the specimen. For the specimen, the suction is defined as a difference between the air pressure applied and the pore water pressure measured. The soil moisture is measured with the water displacement through the ceramic disk equipped in the pedestal of the pressure chamber. In this method, SWCCs for a soil specimen in drying and wetting process are measured in two or three days. It is found that soil moisture characteristic curves in drying and wetting processes obtained by new testing apparatus were in acceptable agreement with those obtained by conventional test apparatus. It was also verified that the testing time of retentively test with continuous pressurizing method is notably shorter than that of with conventional test method. In this paper, the measured results for several soil are shown, and the applicability of this method is examined.