高地下水位弧底梯形渠道混凝土衬砌冻胀破坏力学模型探讨

Dynamic model for frost-heaving damage of concrete lining trapezoidal canal with arc-bottom at high groundwater level

【目的】探讨高地下水位弧底梯形渠道混凝土衬砌结构冻胀破坏的力学模型,为实际工程中衬砌体的设计与建设提供参考。【方法】根据冻土力学、材料力学及高等数学知识,提出渠道坡板的计算简图是在法向冻结力、切向冻结力和法向冻胀力共同作用下的简支梁,渠底板是与两衬砌相互作用的压弯构件,进而依据合理的简化和假设,提出并建立高地下水位弧底梯形渠道混凝土冻胀破坏的力学模型,并进行了实例应用研究。【结果】通过建立的高地下水位弧底梯形渠道混凝土冻胀破坏力学模型,不仅能计算出弧底梯形渠道坡板、底板的控制内力及最大弯矩作用点,而且可以计算出渠道衬砌渠坡板所受的法向冻结力,并可估计混凝土板可能发生胀裂的位置。【结论】弧底梯形渠道混凝土衬砌结构法向冻胀力小,法向冻结力作用点在距渠顶1/5处,整体变形及抗冻胀能力强,并优于梯形渠道,为以后的渠道防冻胀设计提供了科学依据。

【Objective】 This study aimed to establish a dynamics model for analysis of frost-heaving damage of concrete lining trapezoidal canal with arc-bottom at high groundwater level to guide the design and construction of the lining scientifically.【Method】 Based on knowledge from soil mechanics,material mechanics and higher mathematics,the calculation diagram of the canal was proposed.It was a simply supported beam under combined action of normal freezing force,tangential freezing force and normal frost heaving force.The baseboard of canal was a compression-flexure part interacting with two lining flexures.According to the reasonable assumptions and simplifications,the mechanical model was established and the application of it was discussed with living example.【Result】 The established dynamics model was capable to calculate the internal forces of trapezoidal canal slope board and the backplane,the normal frosting force and the possible locations where splitting was likely to happen.【Conclusion】 The normal frosting force of trapezoidal canals with concrete lining is small and the point of normal freezing force is at the one-fifth position.Its overall distortion and anti-frost heaving ability are better than trapezoidal channel.This study improves the future anti-freezing researches on channels.