梯形渠道砼衬砌冻胀破坏的力学模型研究

通过对梯形渠道砼衬砌冻胀破坏机理的分析，指出了渠坡衬砌板的计算简图为在法向冻结力、切向冻结力、法向冻胀力及衬砌板约束力作用下的两端简支梁；渠底衬砌板和两衬砌板都属压弯组合变形构件。提出了梯形渠道砼衬砌冻胀破坏的力学模型，并解出了渠坡衬砌板、渠底衬砌板控制内力及最大拉应力计算公式，结合砼板抗裂条件给出了冻胀力、胀裂部位、冻胀抗裂衬砌板厚度及抗冻胀破坏验算的一系列计算方法。指出了衬砌板上除重力以外的各种冻结力、冻胀力及相互约束力的大小及方向都是相互依存，最终都可以表达为最大切向冻结力的函数，而最大冻结力则是反映土质、负温及水分状况的综合指标，只要根据经验或实验确定了最大冻结力，力学模型就可求解。工程计算表明该模型是安全合理、简单实用的。

Establishment and application of mechanics models of frost heaving damage of concrete lining trapezoidal open canal

Thorough analysis of the damage mechanism of frost heaving on the concrete lining of the channel with trapezoidal cross section, this article presents the following conclusions. First, it points out that the calculating diagram of the lining plates of canal bottom and slopes are two-ends-simply-supported beam. Both of them are combined deformation members under the loads of bending and compressing. Second, it gives the mechanics models of frost heaving damage of the concrete lining plates of the canal with trapezoidal cross section. And presents the calculating formula of the control internal forces and maximal tensile stresses of the canal slope lining plates and the canal bottom lining plates. Furthermore, by considering the conditions of crack resistance of the concrete plates, it presents a series of calculating methods of frost heaving forces,position of expansion cracks,proper depth of the lining plates to prevent frost heaving and cracks occurrence, and checking calculation for prevention of frost heaving. Finally, it also elucidates that the intensity and direction of the frost heaving forces, adfreezing forces and interactionally restricting forces, except for the gravity, are all interdependent, and they all can be expressed as the function of the adfreezing forces. Moreover the adfreezing forces is a comprehensive reflection of soil quality, negative temperature and the status of moisture, thereby the mechanics models can be solved provided that adfreezing forces is determined according to the practical experience or experiment. Subjecting the models to the field engineering calculating test, its result shows its safety, rationality, simpleness and practicability.