高地下水位弧底梯形混凝土衬砌渠道冻胀断裂破坏力学模型及应用

Development and application of frost-heaving fracture damage mechanical model for concrete lining channel with arc-bottom trapezoidal at high groundwater level

【目的】在线弹性断裂力学的基础上,对高地下水位弧底梯形混凝土衬砌渠道冻胀断裂破坏力学模型进行研究,为弧底梯形衬砌渠道的设计提供依据。【方法】将高地下水位弧底梯形渠道混凝土衬砌简化为简支梁结构并建立其冻胀力学模型,在考虑材料本身缺陷的基础上结合断裂力学理论,提出了高地下水位弧底梯形渠道冻胀断裂破坏力学模型。运用断裂力学及结构力学等相关理论,考虑法向冻结力的作用,通过适当的简化计算弧底梯形渠道衬砌的相关内力,并提出适用于弧底梯形渠道衬砌的断裂力学破坏准则,利用计算实例对所建立的渠道冻胀断裂破坏力学模型进行验证。【结果】渠道衬砌板的冻胀断裂符合Ⅰ-Ⅱ复合型裂纹的特点,通过建立的弧底梯形渠道混凝土冻胀断裂力学模型,可以计算出渠道阴坡、阳坡、渠底的衬砌板厚度。计算实例证明,所建立的高地下水位弧底梯形渠道冻胀断裂破坏力学模型正确可行、简单实用。【结论】弧底梯形混凝土衬砌渠道优于梯形渠道,是一种冻胀力及冻胀变形较小的结构形式。

【Objective】Based on the liner elastic fracture mechanics,this study explored the frost heave fracture damage mechanical model of arc bottom trapezoidal concrete lining channel at the high underground water level,aimed provide to improve the design of arc bottom trapezoidal channel lining.【Method】The concrete lining of high groundwater level arc bottom trapezoidal channel was simplified for the simply supported beam structure and established the frost-heaving mechanical model.Considering the defect of material and combining with the fracture mechanics theory presenting the high groundwater level arc bottom trapezoidal channel frost-heaving fracture damage mechanical model.Using the theory of the fracturemechanics and structural mechanics and considering the normal freezing force,relevant internal forces of arc bottom trapezoidal channel lining were calculated through appropriate simplification and the failure criterion suitable for fracture mechanics of arc bottom trapezoidal channel lining was proposed.The frostheaving fracture mechanical model was also evaluated using numerical example.【Result】Channel lining plate frost heave fracture fit the Ⅰ-Ⅱ complex style fracture,and the lining plate thickness of channel shady slope,sunny slope and channel bottom could be calculated using the established arc bottom trapezoidal channel concrete frost-heaving fracture mechanical model.Calculation examples proved the frostheaving fracture damage mechanical model for arc-bottom trapezoidal channel at high groundwater level was correct practicable simple and useful.【Conclusion】Arc bottom trapezoidal concrete lining channel was structure with small frost heaving force and frost heave deformation was superior to the trapezoidal channel.