A REVIEW OF SELECTED UNEXPECTED LARGE SLOPE FAILURES

Abstract

Significant advancements in the application of soil and rock mechanics have been achieved in
managing the risk of large-scale slope instability. In practice, however, unexpected slope failures do occur,
sometimes with significant safety and economic implications for nearby communities, public infrastructure or
the environment. This review focus on large slope failure case studies, considering the slope failure mechanisms
and the effectiveness of the controls adopted in managing the geotechnical risk. The role of appropriate data
collection and interpretation in underpinning analysis methods is investigated. The impact of levels of
uncertainty of input data on different methods of analysis is addressed in the paper. In some instances, the slope
failure mechanisms are not understood and can therefore not be incorporated into geotechnical models. It is also
found in this review that the safety implications for communities located in the failure path were not initially
evident, in some case, resulting in significant loss of life. A thorough understanding of the failure mechanism
and triggers is essential for assessing slope stability conditions. In addition, reliable stability monitoring,
geological and hydrogeological data are required for determining slope stability conditions. It is also evident
from this review that time-dependent behavior is likely to result in shear strength reduction and should be
considered for long-term slope stability.
Keywords: Slope stability, slope failure, Southern Leyte, Guinsaugon, Vaiont, Yallourn Mine