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2014 Vol.30, Issue 6 Preview Page
Effect of Depth-Variant Soil Properties on Shallow Failure of Slope during Rain Infiltration

깊이별 지반특성변화가 강우침투에 의한 사면표층 파괴에 미치는 영향

Ka-Hyun Park1*
,
Ji-Young Kim2
,
Choong-Ki Chung3
,
Kyung-Suk Kim4
박 가현1*
,
김 지영2
,
정 충기3
,
김 경석4
1Graduate Student, Dept. of Civil & Environ. Eng., Seoul National Univ.
2Graduate Student, Dept. of Civil & Environ. Eng., Seoul National Univ.
3Prof., Dept. of Civil & Environ. Eng., Seoul National Univ.
4Researcher, Korean Expressway Corporation
1서울대학교 건설환경공학부 박사과정
2서울대학교 공학연구소 연구원
3서울대학교 건설환경공학부 교수
4한국도로공사 책임연구원
*교신저자. *Corresponding Author. 
30 June 2014. pp. 41-49
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Abstract

Intensive rainfall causes frequent slope failures at the shallow depths of slopes. Because soil layers at shallow depths of slopes usually become dense, and its permeability and soil strength vary according to depth, forensic studies and stability analyses of shallow slope failure need to consider the depth-variant soil properties. In this study, the effect of depth-variant soil properties on surface failure of slopes during rain infiltration is investigated using numerical analysis. Three different cases considering depth-variant soil properties were conducted and the results were compared. For the analysis, undisturbed soils at three different depths were sampled at actual slope failure sites and the properties including strength and permeability characteristics at each depth were obtained. Stability analysis and seepage analysis were conducted using actual rainfall records. The comparison of the results shows that analysis could lead to an erroneous conclusion according to the way of considering depth-variant soil properties. The case in which depth-variant soil properties were considered predicted similar failure times and failure shapes to the actual failure. Therefore it is recommended that the depth-variant soil properties should be considered for the analysis of shallow slope failure during rain infiltration.

Keywords
Surface slope failure
Infiltration
Depth-variant soil properties
Slope stability

집중강우 시에는 사면의 얕은 심도에서 파괴가 빈번하게 발생한다. 사면의 표층 지반은 심도에 따라서 조밀해지는 특성이 있으며 지반의 투수특성과 강도특성도 달라지므로 강우시 사면의 얕은 심도에서 발생하는 파괴의 원인분석과 안정해석은 이러한 지반특성 변화를 고려할 필요가 있다. 본 연구에서는 사면의 표층 부근의 지반특성 변화가 강우시 사면의 안정성에 미치는 영향을 수치해석적으로 분석해 보고자 하였으며, 표층 근처에서 심도에 따라 구한 지반특성 값을 적용하는 방식에 따라 강우침투와 사면안정해석 결과의 차이를 비교해 보았다. 실제 강우시 파괴가 발생한 사면을 대상으로 사면의 표층에서 심도별로 시료를 채취하여 전단강도와 투수특성 등 지반특성을 구하였으며, 파괴를 유발한 강우기록을 적용하여 침투해석과 안정해석을 실시하였다. 해석결과 깊이별 지반의 특성 변화를 고려한 경우와 단일지층으로 가정하여 고려하는 방식에 따라 간극수압 분포, 예상파괴면, 안전율 변화에 차이가 있는 것으로 나타났으며, 깊이별 지반 특성 변화를 고려하는 경우가 실제 파괴거동과 유사한 결과를 나타내었다. 이러한 결과는 강우침투에 의한 표층파괴현상을 규명하고자 하는 경우 지반의 심도별 지반특성 변화를 고려할 필요가 있음을 의미한다.

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Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 30
  • No :6
  • Pages :41-49
  • Received Date : 2014-03-27
  • Revised Date : 2014-05-20
  • Accepted Date : 2014-06-02
  • DOI :https://doi.org/10.7843/kgs.2014.30.6.41
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