U形衬砌渠道冻胀机理与防渗技术研究

The study of frost-heave mechanism and seepage technical control on U canal

用薄壳结构理论分析U形衬砌渠道抗冻胀机理,认为在冻胀力作用下,U形砌体发生整体上抬时,不象梯形渠道在渠底中部沿渠道轴线方向和在两渠坡距渠坡底1/3处沿渠线方向各形成一条冻胀裂缝,U形衬砌渠道破坏的主要原因是受渠基土壤水分以及不良气象条件影响,同时与渠道走向及受力状态有关,所有这些将使衬砌体发生不均匀冻胀而破坏。依据水力最佳断面条件求解U形渠最佳断面参数,分析我国南北灌区的三种断面形式不同衬砌材料、不同结构形式及不同嵌缝材料的大中型U形衬砌渠道的设计及施工技术,认为在无冻害地区U形衬砌渠道具有良好的防渗性能,在冻胀量不超过5 cm的Ⅱ级基土冻胀性工程地区,在采取适当的防冻措施后,U形衬砌渠道仍然是一种完全适用的、良好的防渗方案。针对U形衬砌渠道目前存在的问题提出了今后应研究的方向。

Mechanism of frost of U canal is studied through shell structure theory and it is found that under the frost- heave force, the lining of U canal will be lifted overall, unlike ladder - shaped canals, which will crack in the middle of canal bottom and along the line locating in 1/3 the length of the slope of two side to the bottom line. The main reason of canal destroyed are soil moistures , meteorological phenomena, canal move towards and strength state on canal, all of these which evenly cause frost heave to canal. The parameter of optimized section of U canal is determined according to water dynamics conditions for sections. All these are analyzed, which include three sections of canals in the north and south china irrigated areas, different lining materials, structure forms, filling materials which are used in the designing and building large or medium sized U canals and it is suggested that U canals have good seepage control in frost free areas, and in areas of heaving bottom , where the value of frost heave does not exceed 5 cm, U canal is a feasible and excellent solution for seepage control provided that proper anti - frost measures are implemented. Some problems about the lining of U Canal to be solved are discussed.