Ranking of geological risks in mechanized tunneling by using Fuzzy Analytical Hierarchy Process (FAHP)

Many variables make foundation conditions unpredicted and uncertain in tunnel and underground constructions which could endanger the safety and adversely impact economy of a project. Evaluating and risk assessment of projects such as mechanized tunneling is necessary to manage and respond to the associated risks, hence, identification of risk factors would be required. In this study by contribution of experienced technicians and use of geological study eight (category) levels of risks are considered. Probability and impact factors are used in the ideal risk analysis. Additionally, in this study ideal and some supplementary factors such as uncertainty of estimates and risk manageability are also addressed. Ranking of risks are determined by Multi-Criteria Decision Making (MCDM) techniques like Fuzzy Analytical Hierarchy Process (FAHP). The present research in Golab tunnel is located in the northwest of Esfahan (Iran), shows that squeezing and face tunnel instability have highest level and gas emissions and clogging of clay have the lowest level of risks.