Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 15, 1835-1849, 2015
https://doi.org/10.5194/nhess-15-1835-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
18 Aug 2015
A method for predicting the factor of safety of an infinite slope based on the depth ratio of the wetting front induced by rainfall infiltration
B.-G. Chae1, J.-H. Lee2, H.-J. Park2, and J. Choi1 1Korea Institute of Geoscience and Mineral Resources, 305-350 Daejeon, Republic of Korea
2Dept. of Geoinformation Engineering, Sejong University, 147-747 Seoul, Republic of Korea
Abstract. Most landslides in Korea are classified as shallow landslides with an average depth of less than 2 m. These shallow landslides are associated with the advance of a wetting front in the unsaturated soil due to rainfall infiltration, which results in an increase in water content and a reduction in the matric suction in the soil. Therefore, this study presents a modified equation of infinite slope stability analysis based on the concept of the saturation depth ratio to analyze the slope stability change associated with the rainfall on a slope. A rainfall infiltration test in unsaturated soil was performed using a column to develop an understanding of the effect of the saturation depth ratio following rainfall infiltration. The results indicated that the rainfall infiltration velocity due to the increase in rainfall in the soil layer was faster when the rainfall intensity increased. In addition, the rainfall infiltration velocity tends to decrease with increases in the unit weight of soil. The proposed model was applied to assess its feasibility and to develop a regional landslide susceptibility map using a geographic information system (GIS). For that purpose, spatial databases for input parameters were constructed and landslide locations were obtained. In order to validate the proposed approach, the results of the proposed approach were compared with the landslide inventory using a ROC (receiver operating characteristics) graph. In addition, the results of the proposed approach were compared with the previous approach used: a steady-state hydrological model. Consequently, the approach proposed in this study displayed satisfactory performance in classifying landslide susceptibility and showed better performance than the steady-state approach.

Citation: Chae, B.-G., Lee, J.-H., Park, H.-J., and Choi, J.: A method for predicting the factor of safety of an infinite slope based on the depth ratio of the wetting front induced by rainfall infiltration, Nat. Hazards Earth Syst. Sci., 15, 1835-1849, https://doi.org/10.5194/nhess-15-1835-2015, 2015.
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This study presents a modified equation of infinite slope stability analysis based on the concept of the saturation depth ratio associated with the rainfall. A rainfall infiltration test was performed using an unsaturated soil column to understand the effect of the saturation depth ratio. The proposed model was applied to assess its feasibility and to develop a regional landslide susceptibility map using a GIS. The approach in this study showed better performance than the steady-state approach.
This study presents a modified equation of infinite slope stability analysis based on the...
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