Liroo dam abutments leakage analysis using DFN-DEM hybrid method

The Liroo Dam is one of the largest concrete dams in the country under study. The objective is to investigate and estimate the amount of water leakage from joints and fractures in dam abutments using numerical method. Interconnected fractures are the main pathways of water flow into the abutments and control the rock hydraulic behavior. Considering the stochastic properties of the geometric parameters of the joints, especially the persistence of the joints, and the presentation of a more realistic model is essential for hydraulic analysis. Therefore, geometric model of discrete fractures network (DFN) was prepared in 3D using 3D-DFN written code. Finally, after validation of DFN model constructed with the extracted values, it is found that the average fit for the different geometrical components and the values ​​of the joints intensities are over 90%. These results were used as reliable inputs of the geometrical model for modeling the hydraulic flow of the left and right abutments using the Discrete Element Method (DEM) in the UDEC software. The total leakage rate was calculated to be 135415 m3 / year. Compared to the useful volume of the reservoir, the total leakage from both supports comprises 0.03% of this useful volume.