화강풍화토는 가장 일반적인 흙의 종류이다. 비등방성 화강풍화토의 응력-변형-강도를 측정하는 것은 사면, 옹벽, 굴착의 변형과 안정을 위하여 매우 중요하다. 불포화 강도특성을 알기 위하여 일련의 불포화 배수삼축압축시험을 시행하였다. 시험시료는 다짐방향에 각각 0, 45, 90도의 축방향각을 갖도록 하였다. 등방압축을 받는 시료의 축변형률은 다짐방향에 의하여 크게 영향을 받으며 이차압축과정에는 시간의존성은 다짐방향과 관계가 거의 없다. 삼축압축강도와 변형에 미치는 다짐방향의 영향은 저구속압과 포화토에서 더 확연한것으로 나타났다. 다짐방향과의 각도를 고려하는 불포화화강풍화토의 강도를 추정하는 방법을 제안하였다.
Decomposed granite soil is the most common type of soils. The measurement of the stress-strain-strength behavior of anisotropic decomposed granite soils is very important for the deformation and stability analysis of slopes, retaining walls, excavations. A series of unsaturated-drained triaxial compression tests were performed to know unsaturated strength properties. The sample had three different angles of the axial (major principal) direction to the sedimentation plane (compaction plane): 0, 45 and 90 degrees. The compression strain of specimens subjected to an isotropic compression was strongly influenced by the sedimentation angle. In addition, the time dependence was independent of the sedimentation angle in relation to the deformation behavior during the secondary compression process. The effect of the sedimentation angle on the triaxial compression strength and deformation was clearly shown with low confining stress. The effect of the sedimentation angle on the compressive strength and deformation was more evident in saturated specimens. A new method of predicting the shear strength of unsaturated decomposed granite soils, considering compaction angles, was proposed.
