Remedial Measures Impact on Slope Stability and Landslide Occurrence in Small-Scale Slope Physical Model in 1 g Conditions

Abstract

AbstractPhysical modelling of landslides by analysing the behaviour of small-scale landslide models subjected to artificial rainfall can be divided into modelling under 1 g conditions and under increased acceleration (n times gravity) in a centrifuge. Physical modelling of landslide initiation began in 1970s in Japan on scaled natural slope models and after initial experiences with field and laboratory research, the small-scale landslide modelling has found a wide application around the world in different aspects of landslide investigations, analysing different types of landslides, different types of slope materials and landslide movements. The main task of landslide physical modelling is research of initiation, motion and accumulation of fast flow-like slides caused by infiltration of surface water or by shaking on a shaking table. Studies that have included landslide mitigation measures into small-scale physical models are rare and have not established correlations with a behaviour of on-site mitigation constructions. This paper discusses the behaviour of small-scale slope models supported by remedial measures under artificial rain in 1 g loading conditions. Models of slope built of different materials, with and without applied remedial measures (gravity retaining wall, gabion wall, pile wall) were exposed to identical intensities of artificial rainfall. The results of the simulations indicated that the slopes supported by remedial measures retained stability of the slope in the same conditions in which the sandy slope collapsed, as well as under significantly prolonged precipitations. At the end of the simulations, significantly higher rainfall intensities were applied to the supported slopes, exceeding the infiltration capacity of the slope material and affecting surface runout. The combination of surface erosion and saturation of superficial layer of a slope caused initiations of flow processes, while complete saturation of a slope when ground water level reached slope surface caused forming of a surface of rupture and consequently movements of the formed landslide body. The data obtained from the geodetic and geotechnical monitoring system enabled understanding of the overall process of rainfall infiltration and soil strength reduction to the development of the surface of rupture in a slope.