【摘要】 <正> 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。更多还原

【Abstract】 Experimental results show that the frost heave ratio of most wind-blown sands with the content of 5 % of <0.05 mm particles under the natural frost penetration rate of 1.5 to 2.5cm per day is less than 4 %, so, most of them are good anti-heave meterials as a lining cushion of canal. The thickness of replacement clayey base with fine sands shouldbe almost the same as the maximum frost depth when the clayey base is impermeable。更多还原