Approach to Characterize Q-Value in Seismic Environments

Empirical methods are regarded as a tool for design of tunnel. Empirical methods have been extensively used in rock mass classification. In most of the projects, the rock mass classification is being considered as the only criteria for designing the complex underground structures. Based on the recorded information, the underground structures enjoy higher level of safety against dynamic waves compared to surface structures. Previously, the seismic design of underground structures have paid less attention than that of surface structures, while designing underground structures without considering seismic loads would result in an unsafe structure. Taking into account the seismic effect in rock mass classification is a new topic which has been addressed in this paper. Moreover, it has been attempted to investigate the seismic effect in the Q-system using numerical analysis. Firstly, the effect of joint sets on seismicity of the tunnel is studied and analyzed in static and pseudo-static states. Then, the results obtained from this analysis are compared and counterbalanced with the results of Q-system. After comparing and analyzing the results, a relationship has been proposed for the effects of seismic behavior in Q-system. The solved examples give reasonable and acceptable results.