The retrogressive successive rotational landslides of soil slope on hillside along the Dschang-cliff highway (West Cameroon), inferred by the geomorphic features and processes
摘要
November 5, 2024, registered the retrogressive successive rotational landslides of soil slope on hillside along the Dschang-cliff highway (West Cameroon). This paper presents the results of slope movement monitoring and geomorphic investigation to understand the characteristics of these active landslides and creates awareness of unstable factors in roads that pass within hilly and mountainous terrains. The soil slope is deep enough to generate circular slip lines that support the rupture surfaces of landslides, which can be approximated by half an ellipsoid, indicating that the landslides yield rotational movements, which are successive and retrogressive. The first landslide has a total length of about 104.4 m and a width of about 50 m, with a height difference of about 30 m, whereas the second landslide has a total length of about 152.32 m and a width of about 80 m, with a height difference of about 60 m. The disrupted material volumes are respectively about 34.15 m3 and 159.43 m3. The disruption of the balance of forces of the soil slope is mainly related to the highway excavation. The break in equilibrium is due to the depletion of the disrupted mass or to at times anthropogenic-induced vibration onto the mass on the verge of collapse. The slope stability then lies on the disturbed mass, which has the role of counter-weight berm. The third landslide would be the biggest, with a half ellipsoid volume of about 1298 m3. Efforts to move the unstable factors in roads that pass within hilly and mountainous terrains are recommended.