Stability of Slopes in Residual Soils

Wesley examines why residual-soil slopes behave differently from slopes in transported soils. He discusses the role of their in-situ weathering structure, bonding, and suction in allowing steep, apparently stable natural slopes, and contrasts this with the tendency for shallow translational failures during intense or prolonged rainfall. The paper argues that analytical methods based on simple effective-stress parameters often cannot capture residual-soil behaviour without careful attention to suction, seepage paths and macro-structure, and it emphasises the importance of field observation and geological assessment.