Centrifugal modelling of rockfall events

Rockfall, and its subsequent motion down the slope, often poses a serious hazard for people and infrastructure. This paper describes the development of a rockfall generation system used to investigate the rockfall behaviour and dynamic process of the overall trajectory in centrifuge model tests. Firstly, the experimental results are compared with the theoretical movement of a free fall event under the hypothesis that this occurs fully in a rotational acceleration field. Secondly, a series of centrifuge model tests were performed to observe the movement of falling boulders, which exhibit various falling modes: free falling, bouncing, rolling or sliding, sometimes associated with fracturing during the falling process, which is not taken into account in most numerical simulations. In order to investigate the influence of a boulder fracturing on the falling velocity and bouncing height, tests were carried out using different parameters for boulder material (stiffness and shape), with the trajectory measurements of the falling boulder captured by a high­speed video camera. The test results revealed that the falling velocity, and the bouncing height in the case of fractured boulders, were larger than those for rolling ones (unfractured).