An Interpretation of Soil Water Retention Curves of Weathered Soils Using Micro-Membrane

Seboong Oh; Seongjin Kim

doi:10.7843/kgs.2021.37.1.17

All Issue

2021 Vol.37, Issue 1 Preview Page Next Page

Research Article

An Interpretation of Soil Water Retention Curves of Weathered Soils Using Micro-Membrane 마이크로 멤브레인을 이용한 풍화토의 함수특성곡선 분석

31 January 2021. pp. 17-27

PDF XML

Abstract

It takes a long period to conduct the test on soil water retention curve (SWRC) in unsaturated soils. To improve such a problem, the high air entry disk has been replaced by micro-membrane. After the soil water retention test, the results by the micro-membrane were compared with those by the ceramic disk. Multiple samples in 5 regions were used to validate that SWRCs by micro-membrane are equivalent to those by ceramic disk. Therefore, a quick procedure based on micro-membrane has been developed, which makes it available to acquire much soil water retention data. The data of SWRCs were obtained for total 29 samples using ceramic disk or micro-membrane. For Korean weathered soils, the unsaturated hydraulic characteristics are sorted by three groups. Based on van Genuchten model, the group is divided by the parameter n, and the value of n could be correlated to the void ratio as each function.

Keywords

Fine particles

Soil water retention curves

Unsaturated soils

Void ratio

Weathered soils

불포화토의 함수특성시험은 오랜 기간이 소요된다. 이를 줄이기 위하여 고압 공기합입치 디스크를 마이크로 멤브레인으로 대체하였다. 마이크로 멤브레인을 적용한 함수특성시험을 수행하여 그 결과를 세라믹 디스크를 이용한 시험결과와 비교하였다. 5개 지역에 대하여 많은 시료를 분석한 결과 마이크로 멤브레인을 적용한 함수특성곡선은 세라믹 디스크를 이용한 시험결과와 유사한 것으로 검증되었다. 이로 인하여 마이크로 멤브레인을 이용하여 신속한 절차기법을 개발하여 많은 양의 함수특성 성과를 획득할 수 있게 되었다. 그리고 마이크로 멤브레인을 이용한 시험을 포함하여 총 5개지역 29개 시료에 대한 함수특성곡선 데이터베이스를 구축하였다. 국내 풍화토에 대하여 불포화 수리특성은 세 그룹으로 분류할 수 있었다. 각 그룹은 van Genuchten 모델 물성치 n값에 따라서 분류되며 n값은 간극비의 함수로 상관관계를 찾을 수 있었다.

References

Kim, Y. K. (2009), "Soil slope design and stability evaluation methodology considering hydraulic conductivity and rainfall characteristics", Ph.D. Thesis, KAIST.

Jung, Y. S., Sa, H. D., Oh, S. B., and Lee, J. S. (2015), "Soil Water Characteristic Curve Using Volumetric Pressure Plate Extractor Incorporated with TDR System", Journal of Korea Geotechnical Society, Vol.31, No.8, pp.17-28. 10.7843/kgs.2015.31.8.17

Fredlund, D.G. and Rahardjo, H. (1993), Soil Mechanics for Unsaturated Soils, John Wiley & Sons, p.517. 10.1002/9780470172759

Lu, N. and Likos, W. J. (2004), Unsaturated Soil Mechanics, Wiley, New York.

Nishimura, T., Koseki, J., Fredlund, D. G., and Rahardjo, H. (2012), "Microporous Membrane Technology for Measurement of Soil-Water Characteristic Curve", Geotechnical Testing Journal, ASTM, Vol.35, No.2, pp.201-208 10.1520/GTJ103670

Oh, S. and Lu, N. (2014) "Uniqueness of the Suction Stress Characteristic Curve under Different Confining Stress Conditions", Vadose Zone Journal, 10.2136/vzj2013.04.0077. 10.2136/vzj2013.04.0077

Oh, S., Lu, N., Kim, Y. K., Lee, S. J., and Lee, S. R. (2012), "Relation between the Soil Water Characteristic Curve and the Suction Stress Characteristic Curve: Experimental Evidence from Tests on Residual Soils", Journal of Geotechnical and Geoenvironmental Engineering, Vol.138, No.1, pp.47-57. 10.1061/(ASCE)GT.1943-5606.0000564

van Genuchten, M. T. (1980), "A Closed-form Equation for Predicting the Hydraulic Conductivity of Unsaturated Soils", Soil Science Society of America Journal, 44, pp.892-898. 10.2136/sssaj1980.03615995004400050002x

van Genuchten, M. T., Leij, F. J., and Yates, S. R. (1991), The RETC Code for Quantifying the Hydraulic Functions of Unsaturated Soils, EPA 600/2-91/065.

Information

Publisher :The Korean Geotechnical Society
Publisher(Ko) :한국지반공학회
Journal Title :Journal of the Korean Geotechnical Society
Journal Title(Ko) :한국지반공학회 논문집
Volume : 37
No :1
Pages :17-27
Received Date : 2020-11-19
Revised Date : 2020-12-22
Accepted Date : 2021-01-18
DOI :https://doi.org/10.7843/kgs.2021.37.1.17

Journal of the Korean Geotechnical Society ISSN:1229-2427(Print) 2288-646X(Online) 한국지반공학회 논문집

All Issue