Slope stability against rainfall and preventive measures
Leong, Eng Choon
Ng, Yew Song
Pang, Henry Tam Cheuk
Hua, Chai Juay
Date of Issue2009
Structural Inspection and Restoration of Building Safety (2009)
School of Civil and Environmental Engineering
Slope failures caused by rainfall are common occurrences in Singapore and Southeast Asia. Many residual soil slopes have a deep groundwater table with a thick unsaturated soil zone above the water table. Infiltration rate into slopes is governed by permeability of the unsaturated soil above the groundwater table. As a result, changes in negative pore-water pressure or soil suction and consequently in shear strength of unsaturated soil are a function of water content. NTU and HDB have embarked on research collaboration to study the mechanism of rainfall infiltration into residual soil slopes in Singapore under local climatic conditions and the effects of rainfalls on stability of slopes. Unsaturated soil mechanics and unsaturated soil properties are used in assessing stability of slopes against rainfall. Measurements of soil properties are carried out using unsaturated soil apparatuses and technology. In addition, preventive measures for rainfall-induced slope failures are investigated using the principles of unsaturated soil mechanics. Preliminary results of the assessment and preventive measures based on unsaturated soil mechanics principles are illustrated.
© 2009 BCA Seminar on “Structural Inspection and Restoration of Building Safety”.