Steep Slope Stability Assessment Based on Hydrological Characteristics

Steep Slope Stability Assessment Based on Hydrological Characteristics

Each year, steep slope failures occur frequently because inopportune combinations of intensity and duration of rainfall trigger instability of the slopes. An Examination of effects of these two important rainfall factors on steep slope failure is a priority to prevent severe damage of properties and loss of lives resulting from slope failures. Slope failures are often triggered by a wetting band deepening caused by a decrease in matric suction due to water infiltration from the slope surfaces. The existing slope failure warning system in Korea does not reflect mechanical or hydraulic characteristics of unsaturated soils. In this study, geotechnical properties of unsaturated weathered soil, including permeability, soil-water characteristics curve, and shear strength, were examined by a series of experiments to evaluate slope stability. A procedure of steep slope failure risk evaluation is developed to reflect rainfall intensity, rainfall duration, and the mechanical and hydraulic properties of unsaturated soils.