Evaluation of geological hazard of the subway (case study: Ahvaz subway, southwest of Iran)

Abstract

Like other large-scale development projects, the design, construction, and utilization of subway projects have several positive and negative environmental consequences. In this study, geological hazards in the construction phase of Ahvaz Subway Line 1identified and localized. The environmental impacts also were assessed in the surface and subsurface sections. During the surface evaluation, after providing and preparing the required information layers, AHP and TOPSIS methods were used to model the environmental effects in the subway route. During the subsurface evaluation, the subsidence, liquefaction, soil corrosion, and RQD characteristics were examined separately in a vertical section. The results showed that Stations 1, 2, 11, and 12 had the most significant potential for environmental hazards at the surface section. Assessing the subsurface conditions showed that due to the type of alluvial material and lithology and water table, subsidence was possible in a subway route. Due to the region's seismic conditions, seismic stresses can cause soil displacement and tunnel collapse along the subway route, especially during the construction phase. The soil chemical test results showed that soils in the subway route had moderate to severe corrosion potential.