Domenico Gioffrè

A relevant issue in the development of disaster risk reduction strategies is played by design of mitigation measures aimed at reducing risk to acceptable values. For rapid landslides, such as debris flows, sheltering structures are very common mitigation measures realized in exposed areas that allow to protect elements at risk and to stop flowing mass. For the design of these works, the debris flow–structure interaction mechanism is very important. The paper focuses on the evaluation of debris flow–structure interaction mechanism in earth reinforced embankments based on an uncoupled analysis of the interaction in two flow cases (dominant static and dynamic). In particular, a novel approach to evaluate the horizontal stress distribution at different time of the impact phenomenon along the upstream face height of deformable sheltering structures considering the dominant flow component has been proposed. First, impact force over the time against structure is calculated. Subsequently, assuming that debris flow is completely stopped by embankment according to a scheme of accumulation of material behind the obstacle, the deformative response of different geometrical types of embankment is obtained by FEM numerical analysis for considered flow cases. The results of numerical analyses are discussed in terms of horizontal displacements in different control points in sheltering structures. The analysis showed that the deformative response of two geometries of embankments depends on dominant static or dynamic components of impact force.

Qualitative and quantitative estimation of distribution of the existing landslides or that could occur inside a determined area is named landslide susceptibility. The zoning of landslide susceptibility consists of inventory of landslides occurred in the past and identification of the areas where the landsliding could occur in the future. The paper shows the results of a study of fast flowslides susceptibility performed on an area placed between Scilla and Favazzina (RC) regularly and historically interested by rainfall and in some cases by earthquake induced landslides. The trend of inclination and lithological features of the potential detachment zones has been analyzed at 1:5.000 scale. Classes of inclinations, where the most part of detachment zones are clustered, have been identified and the distribution of these classes for each lithological type has been graphed. Among all surveyed events, the inclinations and lithological features of the detachment zones similar to those of the events occurred in the 2001 and 2005 have been found. Finally, in order to evaluate the susceptibility of the area, the paths of flowslides have been evaluated by numerical simulations using the SPH model.