초록

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공중투하법으로 만든 등방압밀 모래공시체를 평면변형률 압축시험을 실시하여 강도.변형특성의 이방성을 연구하였다. 세계 각국의 주요 연구기관에서 사용되고 있는 7종류의 연구용 표준시공시체를 최대주응력방향(e,)의 변형률과 최소주응력방향(e3)의 변형률을 각각 $10^{-60}에서\; 10^{-2}$ 까지 상세히 측정하였다. 그 결과,실험한 모든 모래에 대하여 변형률 0. 001%이하까지의 변형률에 있어서는 최대주응력이 퇴적면과 이루는 각도 5에 관계없이 탄성적.등방적인 거동을 나타내었다. 그러나, 변형률이 증가하여 탄성한계를 넘어면 점차퍽으로 이방적인 성질을 띄게 되고 마침내 피크에 도달하면 최대내부마찰각 $\phi_{max}은 \delta가\; 90^{\circ}에서 0^{\circ}$로 감소함에 따라 감소하고 그 최소치와 최대치의 비는 0.82-0.90 사이에 있었다. 또, $\phi_{max}$값의 최소치는 모래의 종류에 따라 $ \delta=0^{\circ}-30^{\circ}$ 사이에 있었다. 그러나, 잔류상태에 도달하면 모래는 다시 등방적인 거동을 하여 $\pji는\delta$에 크게 의존하지 않고 거의 일정한 값을 나타내었다.

Abstract ▼ AI-Helper

Anisotropy in strength and deformation characteristics of isotropically consolidated sande prepared by pluviating through air was studied by plane strain compression tests. Seven types of sand of the world-wide origins were tested, which have been extensively used for research purposes. The strains...

Anisotropy in strength and deformation characteristics of isotropically consolidated sande prepared by pluviating through air was studied by plane strain compression tests. Seven types of sand of the world-wide origins were tested, which have been extensively used for research purposes. The strains for direction of bmazimum principal stress and direction of minimum principal strews were measured continuously from $10^{-6}\; to 10^{-2}$. The following results were obtained for all sands. The behaviour at strains leas than about 0.001% was elastic and isotropic regardless of the angle $\delta\; of\; the\;\sigma$ direction relative to the bedding plane. However, the sands became gradually more anisotropic as the strain increased to the extent exceeding the elastic limit. The peak strength was noticeably anisotropic with a similar trend. Thus, the angle of internal friction $\phi\; decreased \;as\;\delta$ decreased from $90^{\circ}$, and the ratio of the smallest to largest values of was between 0.82 and 0.90. The l has a minimum at $\delta=0^{\circ}~30^{\circ}$ depending on the hypes of sand. The residual strength became isotropic again.

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