Numerical finite element analysis of underground tunnel crossing an active reverse fault: a case study on the Sabzkouh segmental tunnel

ABSTRACT

The study of past earthquakes indicates that permanent landform variations are the main cause of tunnels failure in comparison with seismic vibrations. In this study, the effect of reverse fault displacements on tunnels has been investigated using 2D and 3D FEM. An explicit dynamic analysis method has been used to take the effect of fault movement into account. The effect of different factors such as tunnel position, crossing angle, dip angle and soil characteristics surrounding the tunnel have been studied. As a case study, the behavior of Sabzkouh tunnel located in Chahar Mahal-e Bakhtiari province, Iran is investigated at the intersection with Sulaghan fault. Due to the displacement of the Sulaghan fault, the most damage to the Sabzkouh tunnel will be from the connections area. A brief discussion on the design countermeasures to reduce the effects of reverse fault movement is also included.

KEYWORDS:

• Underground tunnel
• finite elements method
• surface faulting
• Sabzkouh tunnel
• seismic design

Acknowledgments

The authors would like to thank A. Eftekhari for helpful comments on the engineering geological and seismotectonics of the Sabzkouh water conveyance tunnel. This study was also supported in part by a research fellowship from the University of Kashan. We also thank the anonymous reviewers for their helpful and constructive comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.