ABSTRACT
Catastrophic extreme runout rock avalanches, known as sturzstroms, are characterised by having a spreading efficiency (ratio of runout length to fall height) that is a function of rock volume. Tests using non-fragmenting blocks or flowing sand fail to capture this behaviour. However, centrifuge tests on avalanches consisting of fragmenting coal and chalk produce analogous relationships to that seen in the field, albeit over a lower range of volume. Normalised runout for both laboratory and field scale events has recently been found to be a function of Hardin’s relative breakage measure, BR. However, previous research on particle breakage within sands has shown the increase in surface area per unit mass, Sm to better correlate with plastic work per unit volume than BR. Here an investigation is made into a possible correlation of normalised runout with Sm for laboratory rock avalanches. The results are discussed in light of the differences between static (slow) fracture and dynamic (fast) fragmentation.
