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| DOI：10.13522/j.cnki.ggps.2026016 |
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| Fracture mechanics analysis of trapezoidal canal linings with pre-existing cracks under bidirectional frost heave in frozen soil |
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Wu Lang, Yang Shuai, Tian Yufeng, Xiao Min, Jiang Haoyuan, Li Hao
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1. School of Civil Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013, China;
2. Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of
Eco-environment and Resources, Lanzhou 730000, China
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| Abstract: |
| 【Objective】Concrete lining cracking caused by frost heave poses a major threat to the structural safety and serviceability of irrigation canals in cold regions. This study investigated the mechanical initiation and propagation of cracks in concrete linings of trapezoidal canals subjected to bidirectional frost heave in frozen soils.【Method】The study was based on frost-heave mechanics and linear elastic fracture mechanics. A cracking criterion incorporating the combined effects of sectional bending moment and axial force was established, with the difference in frost-heave intensity between the normal and tangential directions characterized by a bidirectional frost-heave coefficient (ε). A fracture-mechanics model for canal linings subjected to frost heave was developed and applied to a trapezoidal canal in Baiyin City, Gansu Province, to analyze the effect of ε on sectional axial force, stress intensity factors and the appropriate lining-slab thickness.【Result】①The bidirectional frost-heave coefficient did not significantly affect the variation in stress intensity factors across different sections of the canal but significantly affected their magnitudes, which increased with increasing ε. ②Both numerical modelling and experimental results indicated that the critical sections were mainly distributed at approximately 35%-55% of the distance from the slope toe. ③With increasing ε, the absolute value of the sectional axial compressive force decreased. Neglecting bidirectional frost heave underestimated the tensile stress in the lining and thereby compromising structural safety.【Conclusion】The appropriate lining-slab thickness increased linearly with increasing ε. When ε=0.422, the appropriate slab thickness was 12 cm. It is essential to consider fracture-mechanics-based criteria when determining lining thickness to ensure the safe operation of canals in cold regions. This study provides a theoretical basis and technical support for the design of frost-resistant concrete-lined canals in seasonally frozen regions. |
| Key words: canals frost heave fracture mechanics bidirectional frost heave stress intensity factor |
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