Mechanisms of Shallow Rainfall-Induced Landslides from Australia: Insights into Field and Laboratory Investigations

Abstract This paper presents and discusses the mechanisms of rainfall-induced shallow landslides that commonly occur in South East Queensland (SEQ) and northern New South Wales (NSW), Australia. The major factors causing the formation of landslide mass such as geology, weathering, and rainfall patterns were discussed. Results from field surveys and laboratory testing of rock/soil material from landslide masses were presented, and relationships between the material strength and landslide occurrence were drawn. It was found that most of shallow slides were related to sandstone deposits. Those failures occurred on natural slopes and road cuts with the inclination of the failure plane being in the range of 35–45°. For natural slopes where the landslide mass mostly consisted of coarse-grained soil, the relationship between the soil strength and water content was established. In addition, the relationship between rainfall patterns such as intensity and duration, and the landslide occurrence was presented. Based on the data from field work and laboratory results including a series of flume tests, the mechanism of shallow landslides triggered by rainfall events was identified and discussed.