Comparison of SGR method with the results of analytical equations governing groundwater inflow into Amirkabir tunnel

In this paper, using SGR (Site Groundwater Rating) method, 11 km of Amirkabir tunnel has been studied and categorized into quantitative and qualitative classes from groundwater hazard point of view. Considered parameters in this method are: joint frequency, joint aperture, karstification, crashed zone, schistosity, and head of water above tunnel, soil permeability and annual raining. Using SGR method, tunnel site can be categorized into six different classes from no risk to critical. According to this classification more than 60% of Amirkabir tunnel has been located in no risk class and results are compatible with the results of analytical method.Furthermore, approximately 5% of tunnel has been found in critical class that mostly coincides on crashed zones and following analytical method results, inflow rate is 0.46 L/sec/m in this portion of tunnel.