基于双K断裂准则的U形混凝土衬砌渠道冻胀破坏力学模型研究

Fracture Mechanical Model for Frost Heave of U-shaped Concrete Lining Canal Based on Double-K Fracture Criterion

为探讨U形渠道衬砌的冻胀断裂力学模型,采用有限元软件简化模拟混凝土衬砌板初始裂缝扩展,并结合线弹性断裂力学的双应力强度因子的混凝土双K断裂破坏准则,建立了冻胀力与冻结力共同作用下的U形渠道混凝土衬砌板冻胀断裂力学模型。根据混凝土双K断裂准则与冻胀条件下的混凝土衬砌力学模型,计算了U形渠道各部位混凝土衬砌板在初始裂缝扩展情况下,混凝土衬砌板冻胀断裂破坏的临界厚度。通过实例计算,验证了此双K断裂准则下的混凝土渠道衬砌冻胀力学模型具有一定的实际应用价值,为以后的U形混凝土衬砌渠道抗冻胀设计提供了合理的理论参考。

In order to explore the fracture mechanics model for frost heave of U-shaped channel concrete lining,we used finite element software to simplify and simulate the initial crack propagation for concrete lining slab,combining with concrete fracture failure criteria of double stress intensity factors,which was from linear elastic fracture mechanics. The frost heave fracture mechanics model of U-shaped channel concrete lining slab under joint action of frost heaving force and freezing force was established. Through double-K fracture criterion of concrete and the model,critical thickness of concrete lining slab needed to prevent frost heave fracturing could be calculated for each part of the U-shaped channel concrete lining slab in the presence of initial crack propagation. Verified by the calculation of application of examples,the frost heave fracture mechanics model is practical and can provide a rational theoretical reference for the design of frost heave in U-shaped concrete lining canal.