Dam Axis Selection on Soft Rocks Based on Geomechanical Characteristics and Analytical Hierarchy Process: A Case Study of Abnahr Dam, Iran

Abstract

This study discusses the engineering geological investigations for site selection of Abnahr Damsite, in order to select a suitable site from two alternatives. The alternatives are located on Mehrian River, relatively close to each other. Two alternative axes are located on an alternation of marlstone and limy marlstone. Although the rock types in both axes are the same, the engineering geological investigations revealed that their geomechanical characteristics are somewhat different. Based on these differences, one of the axes is more suitable. In this study, two alternative axes were investigated to determine their geomechanical characteristics including rock mass permeability, rock mass quality, RQD, Alluvium conditions, slope stability, and paleoslides. The suitability of the axes was finally judged based on all obtained characteristics of two alternatives. In order to make a rational decision, the analytical hierarchy process technique was used as a decision making support tool to quantify the subjective and descriptive judgments to subjective values. The results show that use of this type of systematic approach in decision making processes is very useful, especially for dam site selection. © 2018, Springer International Publishing AG, part of Springer Nature.