Correlation between structural geological and geotechnical properties of the rock mass at the Lukovo Pole dam site

Summary

Abstract

This paper presents the results from detailed geological investigations carried out at the Lukovo Pole dam site, and makes correlation between the structural geological and geotechnical properties of the rock mass. This issue is particularly interesting in environments with a rather complex geological structure in which tectonics plays a significant role. By resolving the structural geological properties of the rock mass, we provide a proper way to direct the geotechnical investigations and have better understanding of the physical-mechanical characteristics of the rock. In this context, it is particularly important to know the reason for the formation of the terrain, the type of geological structure, and the nature of the discontinuities. The strike and dip direction of the foliation planes have essential role in defining the drainage character of the medium. The Lukovo Pole Dam is located within the Western Macedonian province, which is distinguished as a separate geotectonic unit in Republic of North Macedonia. It is characterized by its complex lithological and tectonic composition, which is manifested by dominant presence of old paleozoic metamorphic rocks and intense folding. This kind of environment requires large scale of variable research methods and techniques. Therefore, for this purpose, numerous field investigations were carried out, consisting of: detail geological mapping, investigative drilling, water permeability tests, dilatometric tests, determination of joint strength testing with sclerometer, construction of investigative galleries, and geophysical tests. By this, the level of awareness for the lithological composition and tectonic impact of the rock mass was very high. These investigations were concentrated mainly along the axis of the dam, the spillway and the diversion tunnel. The dam axis was analyzed as primary zone of interest where total of 14 investigative boreholes were performed. Additionally, side wise two investigative galleries were performed by which direct overview for the geological structure was established.