中文摘要：

依据温度梯度理论,论述了大型U形混凝土衬砌渠道冻胀机理;运用原型观测成果,建立了大型U形混凝土衬砌渠道季节性冻融水热耦合二维模型,采用混合型Richards方程对冻结过程中渠基非饱和土壤水分运移进行了模拟;并用冻结水分运移量、气温和冻深观测值分别建立了冻深、冻胀预测模型。经检验：模拟曲线和预测曲线与原型观测曲线基本吻合。该研究为大型U形混凝土衬砌渠道设计、推广应用提供了理论依据。

英文摘要：

The frost-heaving mechanism of U-shape canal during seasonal freezing and thawing stage was studied based on the temperature gradients theory. A model of coupled heat-fluid transport for U-shape canal lining with concrete during seasonal freezing and thawing stage was developed, and the hybrid Richards＇ equation was used to study unsaturated water movement of frozen soils. The prediction model of frozen depth and frost-heaving deformation were derived with the amount of soil moisture transfer, temperature and observation value of frost depth. The test results show that the simulation and prediction curves are fitting with the observation curve. The research supplies a theoretical basis for the design of the U-shape canal lining with concrete.