渠道复合材料防渗结构型式在滹沱河灌区中的运用

滹沱河灌区续建配套和节水改造工程中共需防渗渠道179．77km，其中忻定、广济两大干渠及其下属的流量大于2m^3／s的支渠和干斗渠共计122．70km均采用复合材料防渗结构型式：两侧护岸为重力式浆砌石墙，渠底及侧墙后铺设0，20mm厚的聚乙烯土工膜防渗，渠底土工膜上铺设覆土保护层。并每隔50m设防冲坎一道。这一型式的成功使用使已建区域的灌溉水利用系数得到很大提高，收到了较为满意的效果。

Application of Canal Antiseepage Structure With Compound Materials in Hutuohe Irrigation District

According to continuing construc ti on and water-saving reform plan of Hu tuohe Irrigation District,the tota l length of canal,which need to reconstruct by antiseepage technique is 179. 77km.Among these canals,122.70k m of canals,induding Xinding,Guangji m ain canal,leteral canals,the disch age of which exceeds 2m 3/s,are adopted antiseepage type with compound mate rials;two leteral wall s are made of g ravity stone masonry,in the bottom o f canal and behind the let eral walls,polyethylene geomembrane 0.2mm thick are s et up,potecting soil layer is placed on the geomembrane,along the canal,anti-scour lips are set u p 50m apart.Using this antiseepage strcture,in some h aving been constructed canals and areas of this irrigation district,the water efficiency of irrigatio n have raise d in a great degrees and some more satisfactory e ffect is obtained .