A multi-dimensional approach to the assessment of tunnel excavation methods

Selection of tunnel excavation method in rock calls for an exact assessment of engineering geology as well as geotechnical conditions of the tunnel strike. Moreover, uncertainties related to properties of engineering geology of rock often trigger complexity. In order to select the best possible excavation technique, one needs to take into account numerous operational, economic, environmental factors, and so forth. Using a hybrid methodology, including multiple attributes decision-making techniques and fuzzy set theory, the present study aims to evaluate the excavation methods of tunnels. The proposed approach is based on fuzzy-AHP and TOPSIS methods where the fuzzy-AHP determines weights of the criteria by decision makers in uncertain environment and TOPSIS concludes rankings of the excavation methods. Finally, a case study of Ghomroud project in Iran is presented to demonstrate the result of the proposed methodology.

► Proper method selection of excavation is a complex phenomenon containing many conflict factors.
► A new comprehensive decision-making model is developed based on fuzzy-MADM methods.
► Preference of criteria and rank of alternatives are modeled by fuzzy-AHP and TOPSIS techniques, respectively.
► TBM is selected by 63.5% of score between excavation techniques in the Ghomroud tunnel case study.