This thesis is part of the context of several works carried out by the study group of Mass Movements formed by the Institutions PUC-Rio and COPPE-UFRJ, led by Professors Alberto Sayão and Anna Laura Nunes. The work seeks to address ways of obtaining the impact forces of Brazilian debris flows, mainly arising from the portion referring to the rock blocks (non-viscous portion) of the movement. The subject still needs well-defined methodologies applicable to cases that, recently, have become an object of study by the technical and academic communities, in an effort to mitigate and/or coexist with mass movements, increasingly present in Brazilian cities. Thus, a methodology is proposed that uses numerical tools such as DAN-3D and ROCFALL to obtain the impact forces of rock blocks in static and dynamic containment structures, taking into account viscous portions and frictional forces, as well as the proposed methodology is compared with existing empirical methods. To obtain the results, we sought to apply the methodology in three recent cases of important debris flows that occurred in Brazil, located in the Serra do Mar, more precisely in the municipalities of Nova Friburgo and Teresópolis in Rio de Janeiro and in São Sebastião in São Paulo.