Hidrodinâmica e análise quantitativa das fraturas nas rochas cristalinas da região de Campina Grande-PB.

Abstract

Storage and exploitation of groundwater crystalline rocks face difficulties due to the complexities in the hydrological properties of crystalline rocks such as rocks metamorphic and magmatic. Usually the fractures in these rocks provide the permeability and porosity necessary for them to be make aquifers. But it is still quite costly and difficult to detect these underground properties and the presence of water in these rocks. The goal this work and to elucidate the nature of the fractures and the conditions that govern the hydrodynamics in the crystalline rocks and try to figure out occurrences of fractures and the areas favorable for the groundwater storage. The research work involved a 25 km radius area with the central point of Campina Big. In the field work, surveys were made on location of rock outcrops, fracture azimuth measurements and lithological description at each location. Field data were used to prepare the fracture maps of each subarea, statistical analysis of the fractures, and classification of fractures in relation to their spacing. The tubular wells and other characteristics existing in the region were placed in the fracture maps in order to observe the correlation between wells and fractures. The highest frequency and occurrence of fractures in the region It is presented in azimuths ranging from N30W to N45E. Dives range from 30 ° to 90 °. The fractures were classified in relation to their frequencies and occurrence and spacing, in classes of frequent local, frequent regional and regional fractures. Correlations were made between the fractures and current failures in the region. In the areas of shearings there is a tendency for occurrences of fractures very frequent sites, micro-fracture beams and fragmented rock. THE drainage formation and valleys in the study region are directly related to fractures; wide valleys, with signs of water, parallel to the intentional fractures or their intersections. This research work showed that there are fractures that serve as water conductors in rocks. O water storage occurs where there is a large intersection fractures with small spacing, as well as in the areas of shear where rocks have a high concentration of micro-fractures and rock fragmentation. Consequently the medium acquires the characteristics of an aquifer.