Slope creep behavior: observations and simulations

摘要

Rock slopes undergoing long-term effects of weathering and gravity may gradually deform or creep downslope leading to geological structures such as bending, bucking, fracturing, or even progressive failure. This study uses geomechanics-based numerical modeling to qualitatively explain the cause and evolution of slope creep behavior. Constitutive models used include the creep, Mohr-Coulomb, and anisotropic models. The last two models are used with the strength reduction in calculation. First, the results of field investigation around a landslide site occurring in slate are present. The causes and modes of creep structures observed on slopes and underground are studied. Second, the study investigates the influences of slope topography and anisotropy orientations on slope creep behavior. Finally, progressive failure of slopes with different shapes is examined. The simulated results show that the bending type of structures develops near slope surfaces, and the buckling type of structures is associated with the deformation or slides of a slope. The creep pattern varies with the orientation and position of an original planar structure. The shear zone involves a joint or fracture along which displacement has taken place. Moreover, creep behavior is more significant on slopes with greater height and inclination as well as on steeper portions whether on concave or convex slopes. In addition, with the same topographic conditions, consequent slopes with coinciding cleavage and obsequent slopes with steep cleavage result in greater creep behavior. Without the effects of anisotropic cleavage, concave and straight slopes develop failure surfaces from the crowns downwards, whereas convex slopes develop failure surfaces from the toes upwards.