In situ rockfall testing in New South Wales, Australia

Despite the significance of rockfall hazards in Australia, this phenomenon is still poorly characterised in many regional environments. In particular, the relationship between slope/rock properties and rockfall motion parameters needs better definition. In the context of rockfall prediction, it is important to quantify the normal and tangential restitution coefficients (referred to as kn and kt) and the equivalent rolling coefficient (μ), which are site-specific. Several series of rockfall tests have been conducted in three different geological environments in New South Wales. The results of the tests show a large variability of the motion parameters, which is due to the natural variability of the blocks and to the randomness of the impact positions. Also, values of kn consistently and systematically higher than the benchmark values from the literature have been inferred. Despite there being no clear correlation between the restitution coefficients and the rotational energy, rotational phenomena are believed to be at the origin of such results.

► In situ rockfall tests with motion characterisation were performed in NSW Australia. ► Results showed values of normal restitution coefficient repeatedly over unity. ► Low impact angles, rotational energy and block angularity can explain these results. ► Tangential restitution coefficient was within the range of commonly adopted values. ► Rolling coefficients were also within the range of commonly adopted values.