Analysis of Steep Cuts and Slopes in Cemented Sand Using Fracture Mechanics

파괴역학을 이용한 경화모래로 이루어진 사면의 해석

  • Published : 2003.12.01

Abstract

Most natural deposits of sandy soil possess some degree of cementation resulting from the deposition and precipitation of cementing agents. The presence of cementation can have a significant influence on the stiffness and volume change behavior, and the strength of soils. An important feature of deposits of cemented sandy soils is their ability to remain stable in surprisingly high and almost vertical man-made cuts as well as natural slopes. Numerous field observations and studies of failures in slopes of cemented soils have reported that application of conventional analysis techniques of slope stability is inadequate. That is not only due to the fact that the failure surface of the slope is not circular, but also the fact that the average shear stress along the failure surface is much smaller than the shear strength measured in laboratory shear experiments. This observation alerts us to the fact that a mechanism different from conventional Mohr-Coulomb shear failure takes place, which may be related to fracture processes, which in turn are governed by fracture mechanics concepts and theory. In this study, steep slopes in cemented sand were assessed using fracture mechanics concepts. The results showed that FEM coupled with fracture mechanics concepts provides an excellent alternative in the design and safety assessment of earth structures in cemented soils.

대부분의 자연상태의 사질토는 어느 정도 경화되어 있다. 경화의 정도는 흙의 체적변형 거동이나 강도에 중요한 영향을 준다. 경화된 사질토 지반의 중요한 특징은 사질토임에도 불구하고 굉장히 높이 서 있을 수 있다는 것이다. 많은 현장 관측이나 경화모래로 된 사면의 파괴 해석들은 기존의 사면해석방법이 적절하지 않다는 것을 보여준다. 이것은 단지 파괴면이 원호가 아니라는 점뿐만 아니라 파괴면에서의 전단응력이 실험으로부터 얻어진 전단강도보다 훨씬 작기 때문일 것이다. 이러한 사실은 파괴양상이 Mohr-Coulomb 전단파괴와 다르다는 것을 말한다. 이런 파괴는 파괴역학 개념과 이론으로 설명될지도 모른다. 이 논문에서는 파괴 역학 개념을 이용해서 경화모래로 이루어진 급경사 사면의 해석을 수행하였다. FEM 해석 결과는 파괴역학의 개념을 이용한 해석방법이 경화사질토로 이루어진 지반구조물의 설계나 안정해석에 훌륭한 대안임을 보여주고 있다.

Keywords

References

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