西北某大型倒虹吸工程设计分析

西北某大型倒虹吸工程设计水头高达300m,输水压力管道长度达2 500m,属于大型倒虹吸工程。由于原工程已不能满足安装使用要求,因此需重建倒虹吸。为了保证倒虹吸工程安全可靠的发挥效能,结合当地的地形地质条件和原工程的使用及管理情况,分析了高水头长距离倒虹吸工程的设计特点,研究了倒虹吸工程的管线布置、管材和管径选择、管壁厚度的确定、伸缩节形式的确定以及加劲环和支撑环设计时注意的问题。综合考虑各种因素,并经比较和计算,基本可选用在原管线上重建,设计时可选用管径为800mm、压力分级可为五级、管壁厚度在8~16mm之间,伸缩节可采用套筒式伸缩节,盘根填料采用聚四氟乙烯石棉,支墩间加劲环间距和位移计算宜采用有限元计算来确定。

Design Analysis of a Large-scale Inverted Siphon Engineering in Northwest China

The inverted siphon is a large-scale project of northwest China which water head is 300 m and the length of water pipeline is 2 500 m. Because the original project can not meet the requirements of the installation and utilization, it needs to rebuild the inverted siphon. In order to making the inverted siphon project safe and reliable, combined with the local geological conditions and the use and management of the project, the characteristics of designing the high head and long distance inverted siphon project were analyzed. It also studied the layout of pipeline, pipe material, pipe diameter selection, the determination of pipe thickness and expansion joint forms, and the designing problems of stiffened rings and supported rings. Considering various factors, the reconstruction on the original pipeline is determined through comparison and calculation. The designing of pipe diameter is 800 mm. Pipe have 5 grade of pressure rating and thickness is between 8-16 mm. Expansion joints can use sleeve expansion joints and using PTFE asbestos as packing material. The spacing of stiffener rings between piers and displacement can appropriately determine by the finite element calculation.