General assessment of soil liquefaction risk using FAHP in the large projects (case study: Tabriz metro line 2)

چکیده مقاله

At the first stage of engineering geological studies for large projects, it is necessary to assess the liquefaction potential of soils with simple and comprehensive methods. Variables which influence the soil liquefaction phenomenon have been identified vaguely and defined only by the use of imprecise linguistic terms. In the current study, a combined model of fuzzy analytic hierarchy process (FAHP) and GIS was proposed in order to assess liquefaction potential of soils along Tabriz metro line 2 (TML2), northwestern Iran. For this purpose, the main criteria and sub-criteria influencing this phenomenon were identified using an extensive literature review, and also a questionnaire reflecting the opinions of a group of experts involved with Tabriz metro project. Totally, seven criteria and 26 sub-criteria were defined, and their weights were calculated by means of FAHP method. Then, GIS-based analysis were used to prepare maps of criteria and related sub-criteria in GRID format. Finally, liquefaction susceptibility maps of soils along Tabriz metro line 2 at depths of 5, 10, and 15 m were prepared. As this comprehensive questionnaire-based method takes more criteria and sub-criteria, it would be possible to rank their priorities and present a real estimation of soil susceptibility to liquefaction using GIS model.