Centrifuge Model Tests of Rainfall-Induced Landslides

Rainfall-induced landslides and debris flows constitute very serious threats to human lives and infrastructure. In many cases, rainfall characteristics which cause the initiation of landslides are not very well determined and this might lead to the misunderstanding of the failure mechanism, the kinematic characteristics and the run-out distance of the failure. In this paper, the design of three series of centrifuge model tests on soil slopes, subjected to rainfall conditions, is presented. The main goal is to investigate rainfall characteristics which cause failure initiation in soil slopes in respect to soil properties and slope geometry. Tests will be performed in a geotechnical centrifuge at the Nottingham Centre for Geomechanics (NCG) under very well defined initial and boundary conditions. For the accomplishment of these tests, a climatic chamber has been developed which accommodates plane-strain slope models and sufficient instrumentation and embodies a rainfall and an evaporation simulation systems. During the centrifuge tests, changes in pore water pressures and soil state as well as deformations of the slopes will be measured, while rainfall intensity and total rainfall will be accurately defined. Three different soil types will be used to create uniform slope models, i.e. fine sand, silty clay and clay, while rainfall intensity will be proportional to the infiltration capacity. The paper describes, also, the saturation and calibration of Druck PDCR-81 miniature pore pressure transducers and SWT5 tensiometers used for pore water pressure measurements.