Rheological behaviour of pyroclastic debris flow

The pyroclastic soils that cover the mountains of the Campania region in Italy are usually unsaturated and collapse due to rainfall infiltration triggering landslides. The evolution of these soils after collapse is not well understood. Indeed, their post-failure behaviour may be "solid-like" or "fluid-like", depending on causes that are not well known. The objective of this paper is the study carried out on the rheological behaviour of the "fluid-like" pyroclastic material with fluid mechanics tools: a vane rotor rheometer and an inclined plane. Two natural pyroclastic deposits have been sampled and different soils-water mixtures have been analysed. The main results have been explained and discussed. © 2010 WIT Press.