Análise de estabilidade e de dano potencial em queda de bloco rochoso no Morro da Boa Vista, Vila Velha/ES

Abstract

The disordered occupation in urban perimeters has caused problems for the population that inhabits these regions, resulting in social and environmental issues, making them vulnerable to floods, landslides, and rockfalls. Geological-geotechnical mapping is an extremely important tool for risk assessment in these areas, grading the risk scale and delineating areas vulnerable to accidents. This study aims to analyze the geological risk in Morro Boa Vista, located in the São Torquato neighborhood in Vila Velha/ES, focusing on the safety factor for block rupture and the possible trajectory in case of their fall. The methodologies employed for creating a virtual model of the outcrop include the use of existing 3D models. For the safety factor analysis, the limit equilibrium method was used for blocks formed by discrete fractures in a 3D model. For the block fall analysis, the rigid body motion methodology was used. When performing the mapping from the virtual model, the orientations of the discontinuities were measured, observing that these condition planar ruptures. Due to the low resolution of the model, the results may be imprecise. A total of five rock blocks were discretized: block no. 5 has already slid; blocks no. 2 and no. 3 were stabilized by engineering works; block no. 4 is supported by blocks no. 2 and no. 3; and block no. 1, the largest with a total volume of 41.6 thousand m³, presented a safety factor of 1.7 even under saturated conditions. To simulate the trajectory of the falling blocks, different block sizes detaching from block no. 1 were considered. The restitution coefficient used should be better studied, as its variation can impact the results. The results showed that the blocks would not directly reach the houses at the base of the hill but could trigger the destabilization of other blocks along the path.