Energy evolution‐based damage quantification and failure prediction of fault zone tunnel lining concrete: A novel acoustic emission–strain energy coupling approach

Abstract This study proposes a methodology combining acoustic emission (AE) technology and strain energy evolution for quantifying damage and predicting the failure of tunnel lining concrete in active fault zones. The test specimens were prepared using the same concrete mix proportions as those used in an actual high‐altitude mountain tunnel project crossing active fault zones. The energy transformation mechanisms during concrete loading were analyzed through uniaxial compression testing integrated with AE monitoring. Results show a significant linear correlation between the AE cumulative absolute energy and the total strain energy, which effectively characterizes concrete damage evolution. Based on these findings, the change rate of AE cumulative absolute energy is proposed as a failure precursor indicator, providing an average advance warning time of 26.4% before concrete failure occurs. Additionally, energy‐based damage variables (the strain‐energy‐based damage variable, and the AE‐energy‐based damage variable, ) were established to accurately quantify concrete damage progression. Furthermore, an energy‐based stress–strain equation was developed to comprehensively describe the mechanical behavior of concrete. These research results provide theoretical foundations and technical support for safety monitoring and early warning systems for tunnel linings in active fault zones, with significant implications for improving tunnel safety in seismically active regions.