Mapeamento geotécnico e ambiental de área de risco em Caçapava do Sul

Abstract

The growth of urban centers in an irregular manner is occurring at an accelerated rate. So, when observing from the geological-geotechnical point of view, a possible problem is perceived, which can cause natural disasters, such as landslides. Thus, geologicalgeotechnical mapping has great relevance for the analysis of this issue, since, through it, it is possible to find ways to mitigate the damage caused by disorderly urban growth in risk areas. Thus, this work aims to identify and characterize risk areas in the municipality of Caçapava do Sul/RS, through environmental and geotechnical mapping, above all, analyzing a street in the neighborhood called Vila Sul, a region of possible risk for landslides. For this, it was necessary to collect data in the field, such as: collection of rock samples, survey of geophysical profiles to characterize soil contact, altered rock and sound rock, in addition to quantifying the thickness of each layer. Satellite image data helped in the development of the work for mapping and locating areas with the greatest topographic variations, enabling the generation of a digital terrain model (MDT). Regarding the geotechnical stability, the FS was obtained by the Bishop method for comparison with the NBR 11682. With the integration of the obtained data, that is, MDT, geophysical profiles, a defined critical section model was created for stability analysis. With the geophysical profile it was possible to characterize two lithologies, the saturated soil and the granite. As a final result, a geotechnical and environmental risk zone map was generated, the results showed low (R1), moderate (R2) and high (R3) risk zones. The safety factor was higher than indicated in the standard, saturated soil FS 3.998, unsaturated soil FS 5.063. This work was also intended to help public bodies on the importance of planning and managing the use of land within urban centers and the measures to be taken to mitigate risk situations already established.