THE OPTIMUM SUPPORT SELECTION BY USING FUZZY ANALYTICAL HIERARCHY PROCESS METHOD FOR BEHESHTABAD WATER TRANSPORTING TUNNEL IN NAIEN

The engineers can frequently encounter with the situation to select the optimum option among the alternatives related with tunneling operations. The optimum choice can be selected by the experienced engineers taking into consideration their judgment and intuition. However, decision-making methods can offer to the engineers to support their optimum selection for a particular application in a scientific way. The Fuzzy Analytical Hierarchy Process (FAHP) is one of the multi attribute decision-making (MADM) methods utilizing structured pair-wise comparisons. This paper presents an application of the FAHP method to the selection of the optimum support design for water transporting tunnel in Naien. The methodology considers six main criteria, considering: displacement values for determined history locations, factor of safety (FOS), cost (total cost), time, mechanization and applicability factor for the selection of support design. The displacements and stress values were obtained by using the finite difference program FLAC2D as the numerical studies have been widely used by engineers examining the response of tunnels, in advance. After carrying out several numerical models for different support designs, the FAHP method was incorporated to evaluate these support designs according to the pre-determined criteria. These studies show that such FAHP application can effectively assist engineers to evaluate the alternatives support system for tunnels.