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2014 Vol.30, Issue 4 Preview Page
Coupled Finite Element Analysis of Partially Saturated Soil Slope Stability

유한요소 연계해석을 이용한 불포화 토사사면 안전성 평가

Jae-Hong Kim1
,
Jae-Seong Lim2
,
Seong-Wan Park3*
김 재홍1
,
임 재성2
,
박 성완3*
1Research Prof., Dept. of Civil Engrg., Chonbuk National Univ.
2Graduate Student, Dept. of Civil & Environmental Engrg., Dankook Univ.
3Associate Prof., Dept. of Civil & Envirnmental Engrg., Dankook Univ.
1전북대학교 토목공학과 연구교수
2단국대학교 토목환경공학과 공학석사
3단국대학교 토목환경공학과 부교수
*교신저자. *Corresponding Author. 
30 April 2014. pp. 35-45
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Abstract

Limit equilibrium methods of slope stability analysis have been widely adopted mainly due to their simplicity and applicability. However, the conventional methods may not give reliable and convincing results for various geological conditions such as nonhomogeneous and anisotropic soils. Also, they do not take into account soil slope history nor the initial state of stress, for example excavation or fill placement. In contrast to the limit equilibrium analysis, the analysis of deformation and stress distribution by finite element method can deal with the complex loading sequence and the growth of inelastic zone with time. This paper proposes a technique to determine the critical slip surface as well as to calculate the factor of safety for shallow failure on partially saturated soil slope. Based on the effective stress field in finite element analysis, all stresses are estimated at each Gaussian point of elements. The search strategy for a noncircular critical slip surface along weak points is appropriate for rainfall-induced shallow slope failure. The change of unit weight by seepage force has an effect on the horizontal and vertical displacements on the soil slope. The Drucker-Prager failure criterion was adopted for stress-strain relation to calculate coupling hydraulic and mechanical behavior of the partially saturated soil slope.

Keywords
Limit equilibrium method
Slope stability
Finite element analysis
Drucker-Prager model
Partially saturated soil slopes

사면의 안정성을 위한 한계평형해석은 간편함과 적용성 때문에 가장 널리 적용되고 있다. 이러한 간편한 방법으로 균질하지 않고 방향성 있는 지층 같은 다양한 지형조건을 해석하기에는 신뢰성과 설득력 있는 결과를 주기에 한계가 있다. 또한 지반굴착과 성토지반 같은 토사사면의 초기 응력상태나 응력경로와 같은 지반의 응력변화에 대해서 고려하지 못한다. 반면, 한계평형해석과는 다르게, 유한요소법에 의한 변형과 응력분포 해석은 시간에 따른 복잡한 하중단계와 탄성영역외의 범위를 다룰 수 있다. 본 연구에서는 불포화 토사사면에서 발생하는 얕은 파괴의 안전율 계산과 임계단면을 결정하는 방법을 제안한다. 유한요소해석은 유효응력 거동을 근간으로 각 요소들의 가우스 포인트에서 응력들이 계산되고 안전율이 가장 약한 지점들을 찾아 비선형 임계단면이 결정된다. 이러한 사면안정해석은 강우 침투에 의해 변형되는 지반의 사면 표층파괴에 적합하게 계산된다. 침투에 의한 지반의 단위중량의 변화는 사면의 연직 및 수평변위에 영향을 주며, Drucker-Prager 파괴기준은 수리학-역학적인 연계된 불포화토의 거동 해석과 응력-변형률 관계를 위해 적용된다.

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Received : September 26th, 2013
21
Revised  : January 8th, 2014
22
Accepted : April 3rd, 2014
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 :4
  • Pages :35-45
  • Received Date : 2013-09-26
  • Revised Date : 2014-01-08
  • Accepted Date : 2014-04-03
  • DOI :https://doi.org/10.7843/kgs.2014.30.4.35
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