Slope failures along discontinuous planes and their shear strength

Slope failures have frequently occurred along discontinuous planes during a small amount of rainfall. The discontinuous planes were chosen as following: 1) the boundary plane between talus cone and ground, 2) the fractured clay in landslide area, 3) the joint developed in slate, 4) the thin glossy black soil adhered to joint or schist of metamorphic rock, 5) the boundary plane between granite and decomposed granite, 6) the boundary plane between decomposed granite and clay vein, 7) the boundary plane between schist of pelitic schist and the decomposed soil, 8) boundary plane between schist of pelitic schist-hornfels and the decomposed soil. Field and box shear tests were performed on the specimen having the discontinuous planes. These test results suggest that the strength parameters should be used in the stability analysis of cut slopes having the discontinuous planes.

field test

box shear test

discontinuous plane

fractured clay

thin glossy black soil

clay vein

granite

joint

schist