Dynamic model to forecast slope stability - a case study: Geradiella lanslide site

Abstract

Forecasting the potential for disastrous events such as landslides has become one of the major necessities in the current world. Most of the landslides occurring in Sri Lanka are found to be triggered by intense rainfall events. This study was carried out on a landslide that occurred near Gerandiella waterfall, located in Kotmale Divisional secretariat in Sri Lanka. This project investigates the possibility of developing a dynamic model to map the spatial distribution of the slope stability using Geographic Information System (GIS). The model incorporates several theoretical models including the infinite slope model, Green Ampt infiltration model and Perched ground water flow model. A series of rainfall values can be fed to the model as the main input to simulate the dynamics of slope stability. Hydrological model developed using GIS is used to quantify the perched water table height. Infinite slope stability model is used to quantify the degree of slope stability in terms of factor of safety. DEM was built with the use of digitized contour data. Stratigraphy was modelled in Surfer software using borehole data and resistivity images. This model equipped with the predicted rainfall values can be used to forecast the slope dynamics of the area of interest.