Rockfall is a natural hazard that needs to be rigorously managed along all the major road and railways transport networks by identifying the most appropriate mitigation measures. There has been significant progress in rockfall modelling and rockfall protection systems in recent years but there remains one aspect that is not very well understood and quite challenging to account for in the design of rockfall protection structures, namely the fragmentation of falling blocks upon impact. Rocks often break up upon impact, which leads to a change in size, shape and energy of falling blocks, parameters that affect the design of the protective structures. Before being able to incorporate fragmentation into predictive trajectory models, it is required to better understand the fragmentation process and its likely outcome (number, volume of fragments and their trajectories). To that aim, an innovative experimental setup was developed at the University of Newcastle (Australia) to study rock fragmentation upon impact. The setup was designed to perform controlled vertical drop tests and record the following impact parameters: impact force, impulse, impact duration, velocities (of the block before impact and its fragment after impact) and all components of energy, pre and post impact. Six views (four high-speed cameras and two mirrors) are used for an accurate reconstruction of the 3D trajectory of blocks and fragments, in translation and rotation. This paper presents the validation of the setup via two series of drop tests using mortar spheres. Attention was focused on the evaluation of impact force and impulse from load cells placed under the impacted surface, tracking of translational and rotational velocity and the computation of total kinetic energy (before and after impact) and all components of energy dissipation. The results confirm that the experimental setup and the approach developed can be used to obtain impact force, impulse and to compute the energy balance during the impact and fragmentation and conduct advanced fragmentation testing.

落石是一种自然灾害，需要通过确定最合适的缓解措施来严格管理所有主要公路和铁路运输网络。近年来，在落石建模和落石防护系统方面取得了重大进展，但在落石防护结构的设计中，仍有一个尚未被很好理解且极具挑战性的方面，即落石在撞击时的破碎。岩石经常在撞击时破碎，这会导致下落块的大小、形状和能量发生变化，这些参数会影响保护结构的设计。在能够将碎片纳入预测轨迹模型之前，需要更好地了解碎片过程及其可能的结果（数量，碎片的体积及其轨迹）。为此，纽卡斯尔大学（澳大利亚）开发了一种创新的实验装置来研究撞击时的岩石碎裂。该装置旨在执行受控垂直跌落测试并记录以下冲击参数：冲击力、冲量、冲击持续时间、速度（冲击前的块及其冲击后的碎片）以及所有能量成分、冲击前和冲击后。六个视图（四个高速摄像机和两个镜子）用于在平移和旋转中准确重建块和片段的 3D 轨迹。本文介绍了通过使用砂浆球进行的两个系列跌落测试来验证设置。注意力集中在对放置在受冲击表面下的称重传感器的冲击力和脉冲的评估上，跟踪平移和旋转速度以及计算总动能（撞击前后）和能量耗散的所有分量。结果证实，实验装置和开发的方法可用于获得冲击力、冲量并计算冲击和破碎过程中的能量平衡，并进行高级破碎测试。