Field infiltration characteristics of natural rainfall in compacted roadside slopes

Wetting depth in a slope is an important indicator to properly evaluate the rainfall-induced slope instability. This rainfall infiltration has potential to induce shallow slope failures. It is necessary to characterize the field infiltration and movement of the wetting front due to a natural rainfall. To monitor important infiltration characteristics of a field slope, a compacted roadside slope in an express highway (South Korea) was instrumented to measure variations of matric suction and water content. The monitored variations of matric suction and water content in vegetated and nonvegetated areas are discussed. The pattern of field infiltration by severe rainfall storms is also compared with the estimation results obtained by widely used ID infiltration models. The Chu model, by considering the ponding and run-off at each time interval, showed a good agreement with the field measurements. DOI: 10.1061/(ASCE)GT.1943-5606.0000160 CE Database subject headings: Unsaturated soils; Slope stability; Rainfall; Infiltration; Highways and roads. Author keywords: Unsaturated slope; Natural rainfall; Rainfall infiltration; Wetting front depth.