Defining engineering-geological characteristics of the terrain planned for foundation of small hydropower plant "Zrnovska River 353"

At the entire surface of the investigated field can be seen metamorphic rocks from Rifei -Cambric age. According to the mineral composition it can be concluded that it is albite-quartz-sericite- chloritic schist (Sab). From the ground provided for the foundation of the dam for small hydropower plant "ZRNOVSKA RIVER 353", from the stage of geological investigations it is conducted a detailed engineering geological mapping of the terrain and for this purpose are analyzed 15 measuring points. The measurement points were set up along the selected profile lines. In this paper are given engineering-geological properties of the rock mass along the profiles 4-4 ', 6-6', 8-8 'and 3-3'. The most important issue during the mapping of schist metamorphic rocks is to determine foliation which is a predisposed structure to the development of cracks. On the investigating area are developed three families (systems) of cracks with different orientation, angle of decline and density. At the terrain along the researched profiles at first is calculated RQD parameter (indicator of the quality of rock mass) and also has been given the classification of the rock masses according Bienawski (RMR system 1989) i.e. defined quasi homogeneous zones in the rocky massif. Of these quasi homogeneous zones has been performed categorization of the rocks according to construction norms GN-200 (Brauns-Stini) and defines the method of excavation in them. Keywords: engineering geological mapping, cracks , profiles, RQD parameter, RMR system