Investigation of Geological Limitations for Subway Tunneling in Ahvaz City, Iran

This article endeavors to provide some of the geological limitations that could impose some problems on Ahvaz city subway project in Iran. Urban development together with growth of industry and population are leading to the spoliation and dereliction of land. So, planning and in turn urban geology may play their key roles. Thus, a need for conducting detailed engineering geological and geotechnical investigations for urban expansion is increasing day by day. This is of major concern in Ahvaz city, the capital of Khuzestan Province, where a subway rural transportation project is going on. The three major problems are discussed here. The first is due to the lithological properties of rocks and alluvium that are composed of Agha Jari Sandstones and Ahvaz Sandstone member of Asmari Formation with different geotechnical properties. Second, hydrogeological features including high level groundwater table and high permeability of the rock and soil layers in addition to their hydraulic relation to Karun river. The third problem is due to seismotectonic framework of the region especially occurrence of Ahvaz active fault that crosses the city that can reduce stability of the tunnels possibly accompanied by liquefaction and uplift during future earthquakes. The paper also explains importance of geological investigations in urban development of the city.