Small- and Medium-Scale Assessment of Rockfall Coefficients of Restitution

Smart Rock (SR) sensors designed at the University of New Hampshire have been used to instrument laboratory and field rockfall experiments. This paper summarizes the results of instrumented small- and medium-scale tests using SRs embedded in the test blocks, performed with the aim to enhance input parameters in rockfall models and to evaluate the contribution of block rotation, often disregarded in energy computations. Fabricated concrete blocks weighing 1 and 13.5 kg were released under controlled conditions onto a poorly graded sand from a height of 1 to 10 m. The impacted surface was also varied at angles between 0 degrees and 42 degrees. High-speed video and SR data were used to determine block translational and rotational velocities of 45 tests and to calculate their energy restitution after each drop. The results demonstrate that different test conditions produce distinct responses in terms of energy restitution, highlighting the difficulty of using fixed coefficients of restitution to realistically model rockfall trajectories.