272-7 Can Short Earthquakes Imitate the long Ones? Seismic Analysis of a Fault-Crossing Tunnel via ABAQUS Explicit with Focus on Critical Point Displacements

Session: Faults, Fractures, and Geomechanics for the Energy Transition (Posters)

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This study examines how fault-crossing tunnels respond to earthquakes of varying durations, focusing on whether short-duration seismic windows can effectively simulate the effects of longer-duration earthquakes, helping to reduce both computational time and costs without compromising the accuracy of displacement predictions. For this purpose, three identical fault crossing tunnel models were created in ABAQUS Explicit to simulate different seismic durations: (1) a 2-second peak acceleration window, (2) a 10-second strong motion window, and (3) the full 90-second acceleration data of the Chi-Chi 1999 earthquake.

The results suggest that the 10-second strong motion window, when appropriately selected from a full-length earthquake, closely matches the displacement behavior of the full earthquake event with only minimal displacement differences (<10% at critical points) except for outliers. The 2-second peak acceleration window, while computationally economical, significantly underestimates cumulative displacements by 30–40%, particularly at critical points. The research findings highlight a pragmatic trade-off: selecting an excessively short seismic window or relying solely on PGA can reduce computational time by ~98%, but it may overlook key displacements and yield outlier results. However, a carefully chosen shorter window can decrease computational time by ~89% while maintaining enough accuracy in displacement-driven evaluations.

However, for precise structural design and long-term stability assessments, where sustained seismic loading is critical, the full seismic event duration is still recommended. This study demonstrates how computational resources can be optimized without sacrificing accuracy in preliminary seismic evaluations in the form of displacements, particularly for fault crossing tunnel models. Future research may explore dynamic scaling methods, complex materials, and variable fault geometries to further enhance this study’s applicability.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7013

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