Geotechnical and Mineralogical Characterisation of Soils from Landslide Scars and Inferred Sliding Mechanism: Case of Limbe, SW Cameroon

The occurrence of landslides in any area may be attributed to the geotechnical, mineralogical and chemical properties of the soils as well as to forces acting on these materials. In this paper, we investigate the role of geotechnical and mineralogical properties of soils in the occurrence of shallow translational landslides in Limbe, SW Cameroon. Laboratory results show that the soils are mainly inorganic silts of medium to high plasticity with clay fraction composed of non-swelling clay minerals. Calculated factor of safety using the infinite slope model for completely saturated soil is greater than 1.5. We therefore propose that failure is generated as a result of fracture enhanced permeability in localized zones of the superficial soils leading to rainwater accumulation and the development of a perched water table in the saprolite from which high positive pore pressure may development and result in the mobilisation of the overlying soil column.