Studies of rainfall-induced slope failures

Rainfall-induced slope failures often occur in steep residual soil slopes with a deep groundwater table. An understanding of these phenomena can be achieved by monitoring slope responses to rainfall over a long period. This paper discusses the various aspects of an instrumentation program for rainfall-induced slope failure studies. Site selection, ground investigation, characterisation, instrument layout and installation procedures are described. The paper also highlights different instruments that can be installed in a slope for specific purposes and the potential limitations associated with some instruments. Experience gained from a study of five instrumented residual soil slopes in Singapore in the context of protection and maintenance of the instrumented slopes is also discussed.