Estimating Rock Mass Parameters in Block and Matrix Rocks in Devoll Valley

Devoll Hydropower Project in Albania consists of 3 power plants stretching from the village of Maliq to Banja. For the construction of Moglice hydropower, which is the upstream plant of the cascade, a 11 km headrace tunnel is planed from Moglice dam to Grabove underground powerhouse. Approximately 700-800 m of the tunnel will cross through heterogeneous rock masses consisting of different lithology blocks embedded in a fine grained sheared matrix. Estimating the rock mass parameters of this section for tunnelling purposes has been challenging and different methods of classification have been used. The paper at hand will describe the estimation of strength and deformability parameters of the rock mass through the usage of Hoek and Brown Criteria and RocLab software. A comparison will be made with the laboratory tests results to evaluate the effectiveness of the method.