沙漠地区大型供水工程建设的关键技术与方法

Key methodologies for constructing large-scale water supply canals in desert

北疆供水工程由北向南纵贯准噶尔盆地,其中穿越古尔班通古特沙漠的明渠全长166.5 km。20世纪90年代,针对该建设工程,围绕渠道选线、沙基压实、渠床加固、防风固沙、生态环境保护等方面,采用理论研究、技术开发、试验示范,采取科学试验和工程实践相结合的方法,结合12 a的安全运行和动态监测,经过系统分析与评估,总结出一套针对沙漠地区明渠建设的集成技术与方法:(1)采用"渠、林、路集中条带布置"的"平台"建设模式,具有对沙漠扰动小,机械化施工效率高,便于运行管理的优点;(2)渠床风积沙和砂砾石垫层"沙–砂水平同起"干碾压实技术,解决了沙漠地区缺水条件下土料压实以及渠道边坡2种不同特性土料同时压实的技术难题;(3)集成创新了机械固沙与生物治沙技术,充分利用沙漠悬湿沙层土壤水分,建成了110 km无灌溉生物防沙带,构建了防风固沙–减速沉沙–阶梯拦沙的多梯次综合防沙技术体系;(4)结合生物治沙,沿渠道两侧构筑了人工植被修复景观,建设野生动物迁徙通道,改善饮水条件,增加了区域生物多样性,在沙漠中形成了一条绿色生态走廊。

The water supply project in Northern Xinjiang traverses the Junggar Basin from north to south. The open canal in Gurbantungut Desert is 166.5 km long. In the 1990 s,a series of theoretical research,experiments and engineering practices were carried out regarding the field layout of canal line,sand foundation compaction,canal bed strengthening,wind prevention,sand fixation and eco-environment protection et al. After twelve years of operation and monitoring,the following conclusions are drawn through systematic analysis and evaluation：（1） the mode of the concentrated band arrangement for canal,shelterbelt,and road on platform has the advantages of small disturbance to desert,high efficiency in mechanized construction and management. The rolling and compaction technologies of sand foundation,wind-blown sand of canal bed and sand-gravel cushion resolved the technical problem for soil compaction and the compaction of two types of soils in the canal slopes simultaneously in the desert.（3） Using the soil water in the suspension wet sand layer,a biological sand control belt of 110 km long has been built with the mechanical sand fixation and biological sand control. A comprehensive sand prevention technology system including the wind prevention,sand fixation,deceleration of the sand and stepped sand blocking has been constructed.（4） The migration paths of wild animals are guaranteed. Using the biological sand control technology system,the vegetation landscape has been constructed along both sides of the canal. The biodiversity has been increased by improving the conditions of drinking water. A green ecological corridor has been built in the Gurbantungut Desert.