Modelamiento tridimensional de fracturas utilizando la técnica de redes de fracturas discretas aplicado en el túnel de la línea 4 del metro de Rio de Janeiro

Abstract

The knowledge of the fractures behavior and distribution in the subsurface is essential for calculations stability and permeability. In the industry, the behavior estimate is produced by rock mass characterization, getting the geomechanical mapping areas with high or low degree fracturing. Such analyses are performed on two-dimensional environment, which don´t allow us to estimate the fracture medium permeability and flow behavior. The main goal of this work is to present a discrete fracture network three-dimensional modeling, obtaining a more realistic fractured medium geometry and to provide a better rock mass global comprehension. In this context, the proposed methodology was applied by SKB (Svensk Kärbränslehantering) group for the fractures systems analysis present in the rock mass of subway Line 4 tunnel construction on Jardim Oceânico - Gavea in Rio de Janeiro. We used the geological modeling software PETREL, to generate both, the geologic-structure model and the discrete fracture model. The discrete fracture model was generated based on the available data obtained from fractures along the borehole and image logs. The modeling validation was done through the correlation with the provided data from the Sorima. The result shows three-dimensional fractures modeling fit well with geomechanical mapping area, so the analysis shows a good fractured zone correlation ensuring the methodology implementation as well as three-dimensional fractures analysis.