Wetting collapse and failure of and slope tested in centrifuge machine

Abstract

This paper presents a centrifuge model of a silty clay slope. The increase of the gravity accel-eration is applied to the slope under unsaturated conditions. The slope is wetted in flight by means of water injection from the bottom. The deformation of the slope and the subsequent failure is analyzed. In order to avoid difficulties in the installation of sensors in the prototype, the model was built in a box of transparent walls and the slope behavior during the flight was recorded using a digital camera. The images were analyzed using the PIV method (Particle Image Velocimetry) and processed by means of the methodology called PIV-NP with the aim of obtaining accumulated displacements and strains. This methodology is able to provide the strains from PIV measurements following an Eulerian scheme even in case of large defor-mations. The experimental results indicate that the wetting-induced volumetric strains (col-lapse) occurred in the wetting front and the soil located above settled as a rigid block. The slope failure was observed at a certain time before the wetting front reached the slope surface and the failure surface was located close to the wetting front.