Rapid concurrent measurement of the soil water characteristics curve and the hydraulic conductivity function utilizing the continuous pressurization method

Adel M. Alowaisy, Noriyuki Yasufuku, Ryohei Ishikura, Masanori Hatakeyama, Shuu Kyono

Research output: Contribution to conferencePaper

Abstract

Natural disasters including earthquakes, typhoons and heavy rainfalls induce various risks such as slope failures. The conventional unsaturated soils hydrological properties mainly the Soil Water Characteristics Curve (SWCC) and the Hydraulic Conductivity Function (HCF) determination techniques are limited due to the complexity and prolonged time required. Thus a simple method that considers short time and high accuracy under the drying and the wetting phases considering remolded and undisturbed samples is lacking. Through this paper, a novel systematic testing setup utilizing the Continuous Pressurization Method (CPM) that allows rapid, concurrent, continuous, direct determination of the SWCC and the HCF considering both remolded and undisturbed samples was developed. It was found that the air pressurizing rate influence on the obtained SWCC using the developed system can be neglected. It was confirmed that remolded samples do not properly represent the in-situ conditions with significant error that should be carefully considered. It must be noted that applying low air pressurizing rate induces almost linear suction profile, however, it changes into higher order non-linear profile when applying high air pressurizing rates or achieving low degrees of saturation. A correction function based on Van Genuchten (VG) model was proposed which has finally led to obtaining accurate reliable HCFs. Finally, it was concluded that the developed system is rapid, direct, reliable, continuous with accurate repeatability that allows concurrent determination of both the SWCC and the HCF under the drying and wetting phases. Where the system allows concurrent determination of the SWCC and HCF in less than 7% of the testing time required using the conventional methods and considers testing both remolded and undisturbed soil samples.

Original languageEnglish
Pages366-375
Number of pages10
DOIs
Publication statusPublished - 2019
Event7th Asia-Pacific Conference on Unsaturated Soils, AP-UNSAT 2019 - Nagoya, Japan
Duration: Aug 23 2019Aug 25 2019

Conference

Conference7th Asia-Pacific Conference on Unsaturated Soils, AP-UNSAT 2019
CountryJapan
CityNagoya
Period8/23/198/25/19

All Science Journal Classification (ASJC) codes

  • Soil Science

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    Alowaisy, A. M., Yasufuku, N., Ishikura, R., Hatakeyama, M., & Kyono, S. (2019). Rapid concurrent measurement of the soil water characteristics curve and the hydraulic conductivity function utilizing the continuous pressurization method. 366-375. Paper presented at 7th Asia-Pacific Conference on Unsaturated Soils, AP-UNSAT 2019, Nagoya, Japan. https://doi.org/10.3208/jgssp.v07.059