Slope failures in Singapore due to rainfall

Abstract

Singapore experienced a number of major and minor slope failures during the months of December 2006 and January 2007 when the island experienced above average monthly rainfalls. Slope failures varied with respect to slope geometry, soil type and rainfall intensity. On 19 December 2006, Singapore experienced the third highest amount of rainfall in 75 years. The relationship between rainfall intensity and slope failures in Singapore is presented in this paper, particularly for the period from December 2006 to January 2007. Initial observations indicated that most slope failures took place when the total rainfall exceeded 200 mm in one day. It was also observed that many slope failures occurred in the residual soil from the Bukit Timah Granite. The roles of soil type and rainfall intensity in rainfall-induced slope failures are explained in detail in this paper.