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甘肃省民勤县总干渠设计流量25m~3/s,用当地风丘砂(部分经河水冲洗)作防冻垫层,上铺预制混凝土薄板衬砌,1982年完成了62.15km,使每公里的渗漏率由未衬砌的0.708％降至0.31％。但是1981年以来,多次因衬砌被冲而影响供水。1982年据当地水电部门的调查,已衬62km渠段内明显的裂缝总长度达11000m,其中冻胀裂缝约占77％,冻胀面积达16000m~2,隆起高度2—12cm。因此有必要查清:1)风丘砂料之冻胀性;2)适宜的换填厚度。
Minqin County, Gansu Province, the main canal design flow of 25m ~ 3 / s, with the local wind mound (part of the river flushing) for the freezing pad, precast concrete thin lining, completed in 1982 62.15km, so that per kilometer of infiltration The leak rate dropped from 0.708% to 0.31% of unlined. However, since 1981, water supply has been affected several times due to the lining being washed. According to the survey conducted by the local hydropower department in 1982, the total length of obvious cracks in the lining of 62km has reached 11000m, of which the frost heaving cracks account for about 77%, the frost heaving area reaches 16000m2, and the height of the uplift is 2-12cm. Therefore, it is necessary to find out: 1) the frost heave of sand dune; 2) the appropriate thickness of the fill.