Slope failures are common in Hong Kong. A wide spectrum of slope failu
res have been noted. Failures may differ in respect of thickness of fa
iled mass, time of failure occurrence, rotational inclination, failure
movement rate, mobility of debris, etc. Small failures significantly
outnumber large ones. Due to their close proximity to buildings, howev
er, small failures that collapse catastrophically without prior warnin
g are of concern. Intense rainfall, soils that are largely non-cohesiv
e upon saturation, steep terrain, and intense development are consider
ed to be the major causes of the failures. Loss of pore-water suction,
erosion, and pore-water pressure build-up at shallow depths are the m
ost common ways through which rainwater affects the slope stability, a
s short-burst rainstorms are common. The scale of a failure event depe
nds on the intensity, areal extent, position and duration of the trigg
ering rainstorm. Antecedent rainfall has relatively little influence.
The prediction of slope stability in Hong Kong is difficult because of
the highly erratic nature of the hydrological influences and the inhe
rent heterogeneity of local soils. While some of the hydrological and
geological attributes cannot be accurately predicted and effectively c
ontrolled, the hazard can be mitigated by appropriate geotechnical con
trol. (C) 1998 Elsevier Science B.V. All rights reserved.