Simulation of mechanical effects due to the impact of fluid-like debris flows on structures

Design criteria usually applied to estimate the impact force acted by a fluid-like debris flow against a structure generally neglect the actions arising during the initial phase of the impact phenomenon. Recent theoretical studies, mainly developed in the field of coastal engineering, point out, however, the importance of this phase; unfortunately, impact tests reported in literature do not supply results useful to propose simple, but reliable, rules to design safeguarding measures, since recorded impact pressures are widely scattered. In the paper, the initial, impulsive phase of the impact of fluid bodies against structures is numerically (FEA) analysed: simulations are carried out by taking into account different models. Proposed results allow to identify the most important physical and mechanical governing factors, to understand their role in the time evolution of the impact force as well as to estimate the corresponding mechanical effects, such as structural damages and displacements of boulders.