Role of unsaturated soil properties in the development of slope susceptibility map
Alfrendo Satyanaga, Harianto Rahardjo
Abstract
A slope susceptibility map which incorporates unsaturated soil mechanics is essential to the accurate location of areas susceptible to rainfall-induced slope failures. The aim of this study was to develop slope susceptibility maps for zonations within Jurong Formation residual soils in Singapore with the incorporation of unsaturated soil parameters. Slope susceptibility maps were developed through one-dimensional seepage analyses using a transient rainfall infiltration and grid-based regional slope-stability model (TRIGRS) and three-dimensional slope stability analyses using Scoops3D. Laboratory testing of soil properties and two-dimensional (2D) seepage and slope stability analyses were conducted to evaluate the results from the slope susceptibility map. Comparison between the slope susceptibility map and the results from 2D analyses showed that the factors of safety from the slope susceptibility map were consistently lower than those of 2D analyses. Therefore, the proposed method incorporating unsaturated soil in the development of a slope susceptibility map was concluded to be reasonable, on the conservative side.