水-热耦合作用是高寒地区供水渠道劣化失稳的重要因素.以北疆典型供水渠道为研究对象,依据渠道典型断面的监测结果,系统分析供水渠道的温度场和渗流场特征,在此基础上通过数值计算分析湿干冻融耦合循环下供水渠道的水热演化规律,探讨不同运行年份对于渠道水热特性的影响.结果表明:渠基土每年经历了显著的升降温过程以及饱和-非饱和的状态转换,多年来经历了干湿交替、冻融循环的耦合作用过程,其水热问题往往呈现湿干冻融耦合循环的特点.在运行过程中,渠道的水分场、温度场发生显著变化,但这一变化在模型渠道运行3年后已趋于稳定,浅层基土饱和度的增长是造成模型渠道冻胀融沉的主要原因.研究成果可为高寒地区长距离调水工程建设及运维提供科学依据.
Moisture-heat coupling is an important factor for deterioration and instability of canals in cold regions.Taking the typical canal in North Xinjiang as the object,the characteristics of the temperature field and seepage field of the canals were systematically analyzed based on the monitoring results of canals.Then,the water and heat evolution rules of the canals under the wetting-drying-freezing-thawing cycle were calculated through numerical software,and the impact of different running years on the moisture and heat characteristics was discussed.The results showed that the canal foundation soil had experienced significant rise-fall process of temperature and saturated-unsaturated transition every year,and had experienced the coupled process of wetting-drying alternation and freezing-thawing cycle for many years.Its hydrothermal problem often presented the characteristics of wetting-drying-freeze-thaw cycle.In the running process,the moisture field and temperature field of the canal had changed significantly,but this change had become stable after three-years running time of the canal.The saturation increase of shallow foundation soil was the main reason for the frost heaving and thawing settlement of the canal.The research results could provide scientific basis for the construction,operation and maintenance of long-distance water transfer projects in cold regions.