한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

한국지반공학회 (Korean Geotechnical Society)
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유효응력에 근거한 불포화토의 역학적 구성모델

Constitutive Model for Unsaturated Soils Based on the Effective Stress

  • 신호성 (울산대학교 건설환경공학부)
  • Shin, Ho-Sung (Dept. of Civil and Environmental Engineering, University of Ulsan)
  • 투고 : 2011.08.01
  • 심사 : 2011.11.15
  • 발행 : 2011.11.30
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초록

다양한 지반공학적 문제들에서 불포화 상태의 중요성이 강조되면서, 불포화 지반의 열-수리-역학적 현상들에 대한 거동특성을 모사하기 위한 역학적 구성모델 개발이 진행되고 있다. 본 연구에서는 Bishop의 유효응력 정의에 근거한 불포화 지반의 역학적 탄소성 구성모델을 제시하였다. 유효응력에 근거한 구성관계는 유효응력과 온도를 주 변수로 증분 형식으로 표현되었으며, 이를 이용하여 응력 갱신과 강성 텐서를 산정하였다. 개발된 구성모델을 이용하여 THM 현상을 포함하는 불포화토의 1차원 거동, 불포화토의 삼축 압축시험, 그리고 고준위 방사성폐기물 시설의 완충재의 거동 특성에 관한 예제 해석을 수행하여 해의 안정성과 구성모델의 적용성에 대하여 논의하였다. 수치해석결과는 개발된 역학적 구성모델이 THM 현상의 매우 복잡한 거동을 효과적으로 모사할 수 있었으며, 일반적인 불포화토의 거동 해석뿐만 아니라 다양한 환경 조건하에서의 THM 거동 해석에 적용이 가능할 것으로 판단된다.

The importance of unsaturated state in various geo-engineering problems has led to the advance of mechanical constitutive model emulating behavior of unsaturated soils in response to thermo-hydro-mechanical loading. Elasto-plastic mechanical constitutive model for unsaturated soil is formulated based on Bishop's effective stress. Effective stress and temperature are main variables in constitutive equation, and incremental formulation of constitutive relationship is derived to compute stress update and stiffness tensor. Numerical simulations involving coupled THM processes are conducted to discuss numerical stability and applicability of developed constitutive model: one-dimensional test, tri-axial compression test, and clay-buffering at high level radioactive waste disposal. Numerical results demonstrated that developed model can predict very complex behavior of coupled THM phenomena and is applicable to geo-engineering problems under various environmental conditions, as well as interpret typical behavior of unsaturated soils.

키워드

과제정보

연구 과제 주관 기관 : 울산대학교

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