Seismic Loading of Tunnels and Metro Stations

Underground projects are strongly affected by structural properties, which have more ambiguous points in comparison with aboveground structures, and studying about their effective forces and parameters associated with high approximation. On the other hand, due to the complexity of estimating loads in the analysis and design of underground structures, particular problems occur. The aim of this paper is to introduce loads and their magnitude according to standards, research papers and empirical research or experience recommendations. Earthquake effects on underground structures have been investigated by researchers for many years because, in addition to the parameters in earthquake like aboveground structures, response behavior of buried structures during an earthquake is very complex. Acceleration of the project, Structural performance, Soil-structure interaction, Ductility capacity and, etc., are discussed for designing underground structures. Research studies in this field are less lead into exact consequence. Uncertain nature of soil behavior has caused no similar codified and certain procedures for underground structures. Qualitative study on approximate seismic force techniques with the flexible method and introducing a simple solution procedure which is under theoretical obligations is one of the other objectives of this study.