The impact of a debris flow on a structure can have disastrous effects because of the enormous destructive potential of this type of phenomenon. Although the introduction of risk mitigation structures such as the Sabo Dam, the filter dam and more recently flexible barriers is usual, there are very few methods that are universally recognized for the safe design of such structures. This study presents the results of experimental tests, conducted with the use of a specifically created flume, in order to obtain detailed knowledge of the mechanical aspects, and to analyze the dynamics of the impact of a debris flow on different types of structures. The analyses of the tests, together with the calculation of the thrust caused by the flow, have made it possible to analyze the dynamics of the impact, which has shown differing effects, on the basis of the type of barrier that has been installed.

A new automatic method for discontinuity traces mapping and sampling on a rock mass digital model is described in this work. The implemented procedure allows one to automatically identify discontinuity traces on a Digital Surface Model: traces are detected directly as surface breaklines, by means of maximum and minimum principal curvature values of the vertices that constitute the model surface. Color influence and user errors, that usually characterize the trace mapping on images, are eliminated. Also trace sampling procedures based on circular windows and circular scanlines have been implemented: they are used to infer trace data and to calculate values of mean trace length, expected discontinuity diameter and intensity of rock discontinuities. The method is tested on a case study: results obtained applying the automatic procedure on the DSM of a rock face are compared to those obtained performing a manual sampling on the orthophotograph of the same rock face