Role of unsaturated soil properties in the development of slope susceptibility map

Abstract

A slope susceptibility map which incorporates unsaturated soil mechanics is imperative to accurately locate areas susceptible to rainfall-induced slope failures. This study aimed 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 1-D seepage analyses using Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Model (TRIGRS) and 3-D slope stability analyses using Scoops3D. Laboratory testing of soil properties and 2-D 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 2-D analyses showed that the factors of safety from the slope susceptibility map were consistently lower than those of 2-D 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.