Influence of Slope Morphology on the Stability of Earthen Slopes: Fid-Bau Portal

Influence of Slope Morphology on the Stability of Earthen Slopes

Gray, D. H.

Slope morphology or surface topography greatly affects the stability of slopes with regard to both surficial erosion and mass wasting. Topographic parameters normally considered in estimating soil erosion losses and calculating short-term mass stability include inclination and length of slope. Most engineered or man-made slopes are planar in form with an unvarying, down-slope gradient and little, if any, plan-form curvature. Natural slopes do not typically exhibit planar slope faces with uniform, un-varying gradients. Instead natural slopes manifest a variety of complex slope forms and profiles. Slopes that start out with planar topography also tend to evolve over time into equilibrium shapes that seldom are entirely planar. This paper describes conceptual and mathematical models, as well as the results of laboratory tests and field observations, that can be used to determine the effect of slope shape on both mass stability and resistance to rainfall erosion. The results of these analyses and observations show that concave slope profiles appear to be more stable and generate less sediment than uniform, planar slopes. These findings are consistent with conceptual models and they also accord with results of computer modeling of soil erosion on slopes with irregular shapes