Análise de evento de queda de bloco seguido de explosão da rocha no distrito de Banquete, Bom Jardim RJ

Abstract

Rock falls are common phenomena on rocky slopes and bring enormous risk to people and physical structures around. They consist of mass movements that, in general, occur instantaneously and without many warning signs. Because they are usually associated with high elevations, the energies involved in this type of event are high, resulting from high potential energy components which are transferred to kinetic translational and rotational components. In cases which the block weight is high, the effectiveness of the event becomes evident, with devastation of natural areas, collapse of engineering structures and human losses. In the most extreme cases, the impact of a large block can result in large rock explosions (Rock Blasting), resulting in the fragmentation of the block, which can reach the level of spraying, potentially increasing the destructive character of the event and the resulting devastation. These explosions can reach as high levels of energy as any existing non-nuclear bomb, causing shockwaves that can cut down trees hundreds of meters away and devastate entire spaces. There are not many researches available about Rock Blasting coming from falling blocks, so much still needs to be developed about this theme. The present research seeks to reproduce and understand a similar phenomenon that occurred in Banquet district, Bom Jardim-RJ, which resulted in the total devastation of forest area at the top of a slope, with spraying of fragments of varying sizes hurled to varying distances, whose recorded range apex was the roof of a residence distant about 430m from the point of impact. Through the program Meshlab, the creation of a profile very close to reality was achieved to effectively analyze the rock fall in the program RocFall v 6.0. Several hypotheses were simulated in order to better understand the kinetic and kinematic behavior of the fall process and, through a logical sequence of research, a reproduction of the phenomenon was obtained, respecting and creating solutions to the limitations of the program, that works well the fall of blocks, but nothing solves in the question of rock fragmentation. The conclusion of the work identifies the causes that may have jointly potentiated the explosion and proposes mitigating actions for new occurrences.