Continuous pressurization method for a rapid determination of the soil water characteristics curve for remolded and undisturbed cohesionless soils
Adel Alowaisy, Noriyuki Yasufuku, Ryohei Ishikura, Masanori Hatakeyama, Shuu Kyono
Abstract
Natural disasters like earthquakes and heavy rainfall events induce slope failures and other disasters. Proper determination of the water retention properties of porous mediums is necessary. The conventional Soil Water Characteristics Curve (SWCC) determination techniques are limited due to their complexity and lengthy time required. A highly accurate simple remolded and undisturbed samples SWCC determination method that requires a short time is lacking. A novel automatic system which adopts the continuous pressurization method and allows the direct determination of the SWCC in a short time suitable for use with remolded and undisturbed samples was developed. The accuracy of the newly developed system was validated, and it was shown to have excellent repeatability. It is a reliable and direct method that requires a short time for the SWCC determination, with the drying and wetting SWCCs obtainable in less than 10% of the time required using the conventional multi-step flow method. Consideration of the pore water pressure was shown to be necessary when calculating the matric suction utilizing the axis-translation technique. Finally, because remolded samples do not properly represent the in-situ natural conditions, the significant discrepancies should be carefully considered when conducting analysis and proposing countermeasures against unsaturated soil-related Geo-disasters.