Centrifuge model tests on a cohesive soil slope under excavation conditions

Abstract

Problems induced by slope excavations are quite common. An in-flight excavation device was realized to simulate the live excavation of slopes at high g levels during centrifuge model tests. A series of centrifuge model tests was conducted to simulate the excavation of a slope at different inclinations and heights, and the effect of the excavation size was taken into consideration. The displacement histories of points over the slope were measured by an image capture and displacement measurement system. Measurement results showed that the excavation-induced deformation process could be divided into several phases with different displacement distribution features. The excavation was found to only affect a restricted zone of the slope whose boundary could be outlined by an A-surface. A strain analysis was conducted to determine the excavation-induced strain localization area of the slope. The degree of strain localization increased as the excavation time increased, but the width of the strain localization area was nearly invariable. Shear failure first occurred near the excavation surface and then extended upwardly to the slope surface under excavation conditions, while tension failure played a dominant role in the upper part of the slip surface. The strain localization area moved towards the slope surface with an increasing slope inclination. The lower part of the final slip surface was located in the strain localization area.