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| Stability evaluation of cracked section of lining structure based on crack shape and characteristics |
| CHEN Zhimin, SHI Haobo*, ZHANG Runlong, LI Junhong, LU Shuai, TAN Chenglong
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| School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China |
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Abstract To accurately evaluate the safety state of tunnel lining cracked sections, optimize structural design, and determine maintenance timing scientifically, a stability evaluation system was established in this study by integrating fracture mechanics with the ultimate bearing capacity theory. Numerical simulations were employed to systematically calculate the safety coefficients for three key lining parts—namely, the vault, haunch, and side wall—under varying crack depths. A dual-index system, comprising the stability coefficient P (indicating crack stability)and the bearing capacity safety coefficient K (assessing whether the sectional bearing capacity meets requirements), was introduced to analyze the influence mechanisms of various factors on structural safety. The results showed that the post cracking stability of the lining was primarily governed by two factors: first, whether the cracks continued to propagate, and second, the weakening of bearing capacity resulting from the reduction in effective section thickness due to cracking. Furthermore, cracking in one location was found to have a negligible impact on the bearing capacity safety coefficient of other locations, confirming the independence of local crack assessment. Critical crack depths and angles corresponding to different damage grades were also identified. This study provides a quantitative basis for the safety evaluation of tunnel lining cracks, offering valuable references for optimizing structural design theory and scientifically planning maintenance schedules.
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Published: 23 March 2026
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