With the advancement of technology and the possibility of making large underground excavations in difficult geological conditions, dynamic analysis of underground structures against earthquakewaves has been necessitated. In this research, factors affecting response of underground structures to earthquake loading has been reviewed using finite difference numerical method. In modeling, Tabas, Naghan and El-Centro earthquakes are used as typical earth shakes. The changes in amplitude of displacement, velocity and acceleration as a function of changing desired model parameters are recorded and facilitated a sensitivity analysis. Results indicate that design parameters such as diameter and depth of underground structures have greater impacts than geotechnical parameters. Among geotechnical parameters, density and elastic modulus show greater impacts. Friction angle and cohesion have great influence only in terrestrial environments during dynamic analysis and it can be stated that these two parameters have little impacts in rocky environments in the process of dynamic analysis.
There has been a lot of controversy around the issue of earthquake especially for the last century. Once it was believed that effects of earthquake on tunnels and underground spaces is not very important and have long been assumed they have the ability to sustain earthquakes with little damage. But due to significant damages in some underground structures for instance the 1995 Kobe Japan earthquake (Parra-Montesinos et al., 2006), the 1999 Chi-Chi Taiwan earthquake and the 1999 KocaeliTurkey earthquake (Iwatate et al. 1997); few rock mechanic engineers subscribe to this viewpoint anymore. Therefore strong motions or shallow tunnels can be considered as factors which can cause considerable damages to underground structures. The primary purpose of current research in this field is to present methods for analyzing stresses and defections developed in underground structures when they are subjected to arbitrary earthquake loading.
