Influence of geotechnical properties on landslide dam failure due to internal erosion and piping

Abstract

Landslide dams are formed in valley-confined settings where favourable conditions like earthquakes, oversteepened slopes, rainfall and snowmelt affect relativelyweathered bedrocks, leading to downslope movement of mountain materials which, under favourable geomorphic setting, block river valleys creating barrier lakes. Landslide damsmay fail by overtopping or by internal erosion and piping. Presently, stability assessments of landslide dams are done considering the geomorphic characteristics of the blockage mainly, without analyzing the properties of the dam materials. This paper presents results of experiments carried out to study the influence of geotechnical properties of landslide dams to failure by internal erosion and piping. The dam models were made up of mixed and uniform soils of varying grain sizes and other index properties. The results show that characteristic properties of dam materials such as density, soil type, dispersion, degree of compaction, hydraulic conductivity and soil gradation affect the stability of dams and control the time and magnitude of the resulting flood. The present study provides new idea and insight on stability analysis of landslide dams considering sparse research results onmaterial properties of landslide dams, which is relevant in numerical simulation of dams, flood routing and early warning system development. Keywords Landslide dam