A Study on the Seismic Dynamic Response of Deeply Buried Tunnels Crossing Faults under Different Fault Conditions

DOI: https://doi.org/10.62517/jcte.202606208

Author(s)

Sijie Zhou1,*, Zelin Yan2, Songlin Li1, Binlin Wang2

Affiliation(s)

1College of Water Resource and Hydropower, Sichuan University, Chengdu, China 2College of Architecture and Environment, Sichuan University, Chengdu, China *Corresponding Author

Abstract

Tunnels in the high-altitude, seismically active regions of Sichuan and Tibet often face hazards from both earthquakes and active faults. However, how fault geometry affects tunnel response has received limited attention. This study takes a tunnel under construction on the Qinghai-Tibet Plateau as an example. A 3D numerical model was built using FLAC3D to see how the maximum principal stress in the lining changes with fault width from 20 m to 50 m and with fault dip angle from 25° to 90°. In all cases, the stress peaks at the crown and invert. These two locations are therefore the most important for seismic design. Lining stress increases as fault width increases, and decreases as fault dip increases. A dip angle of 25° gives the highest stress. In addition, the fault influence area becomes much wider when the fault is wider or when the dip angle is smaller. These results can help guide the seismic design of tunnels that cross active faults.

Keywords

Fault Zone; Seismic Response; Fault Width; Fault Dip

References

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