Seismic response evaluation of simplified form of tunnel by linear time history analysis

Non-uniform cyclic loading can damage the tunnel structure; for this reason, the present research proposes a simplified form of tunnel for linear time history analysis (LTHA) by using the Hilber-Hughes-Taylor method to evaluate behaviors of the tunnel under the Kobe seismic excitation. To reach this goal, an undamped condition is considered to analyze the proposed model for obtaining an explicit unconditionally stable solution. 9-field studies are addressed in this research, and the model is validated with 2-field studies. The minimum differences in validation results are obtained to be 3.02% and 4.06% for Cankurtaran and Komurhan tunnels, respectively, which may represent a good accuracy of numerical analysis. Also, the minimum difference in application result (i.e., maximum tunnel displacement) between the previous study and present research is found to be 3.64% in the case of the Sabzkuh tunnel. This research may be enhanced in the future by considering damping, more time history functions, etc.