Resilience assessment of the seismic damage mechanism of the Daliang high-speed railway tunnel in the 2022 Menyuan earthquake (Mw 6.7) in China

Abstract

Intense fault dislocation within active fault zones can significantly impact the integrity of fault-crossing underground structures. This research examines the Daliang tunnel on the Lanzhou to Urumqi High-Speed Railway, which was severely damaged by the Menyuan great earthquake (Mw 6.7) in Qinghai Province, China, on January 8, 2022. The background of the earthquake and basic design information of Daliang high-speed railway tunnel is introduced. Field investigations demonstrate the seismic-induced damage, caused by the left-lateral strike-slip fault, can be categorized into five levels: extremely severe, severe, moderate, slight, and basically intact, which helps establish clear identification segments. A detailed analysis of damage mechanisms is conducted for each severity level, revealing that sections near the seismogenic fault experienced significant seismic damage, including pronounced uplift deformation of the roadbed slab, torsional fracture of the lining structure, alignment deformation, and extensive lining detachment, due to the combined effects of transient dislocation and the release of strong seismic motions from seismogenic fault. Other affected sections, affected by seismic vibrations and multiple contributing factors, exhibited varying degrees of damage, such as bottom bulging, fragmentation of the lining inner surface, multi-directional crack propagation, and localized peeling, as well as less discernible distribution patterns. Based on seismic damage classification, zoning, and detailed analysis of seismic damage mechanisms, this study proposes eight seismic resilience evaluation indicators for assessing the seismic damage of fault-crossing high-speed railway tunnels. These indicators include the cross-section area invasion rate, cross-section CPⅢ offset, and cross-section hundred-meter axial displacement rate, among others. A new quantitative standard for seismic resilience specific to fault-crossing high-speed railway tunnels is developed. The application of fuzzy set theory and fuzzy logic in evaluating the seismic resilience capabilities of fault-crossing high-speed railway tunnels is investigated. A resilience evaluation framework for assessing the seismic resilience of fault-crossing high-speed railway tunnels is established. Quantitative comprehensive assessments are conducted on 38 selected seismic damage sections to identify the extent of damage. The results validate the rationality and effectiveness of the proposed performance evaluation system for assessing seismic damage in fault-crossing high-speed railway tunnels. This research provides important references for the post-earthquake structural resilience performance recovery, structural safety assessment, and development of methodologies related to the seismic resilience of fault-crossing high-speed railway tunnels.