兰州西固水厂下游斗槽水力冲沙条件的论证

Hydraulic Sand Sluicing in Lateral Canal at the Downstream of Xigu Waterworks in Lanzhou

兰州西固水厂采用斗槽从黄河取水 ,由于供水扩建工程需要增加下游斗槽的设计引水流量 ,使原水力冲沙效果不好的斗槽冲沙问题更为突出。设计论证从原始资料入手 ,用水力学理论对斗槽的冲沙条件进行了分析计算 ,认为斗槽本身具有一定的水力冲沙能力。根据运行和勘测资料 ,分析论证了影响斗槽冲沙效果的原因并提出了相应的对策 ,确定工程分两步实施 ,首先进行疏浚 ,使斗槽过流断面达到设计的要求 ,然后根据疏浚后的冲沙效果确定是否需要采取工程措施。疏浚以后斗槽的冲洗效果明显提高 ,但尚需较长时间的观测和验证。

The water intake of Xigu Waterworks is situated in a downstream diverting lateral canal from Yellow River. Along with the expansion of the water supply in Lanzhou, the designed diversion flow of the lateral canal have to be expanded, consequently deterioration on the recently poor performing hydraulic sand sluicing in the lateral canal will be even more. Based on the originally designed data, the erosion conditions of lateral canal are evaluated with the theory of hydraulics. It is found that the lateral canal itself has the ability for hydraulic erosion. The reason of lateral canal erosion was analyzed in accordance with the measured and operating data. The countermeasures for the lateral canal erosion were proposed that the project should be completed by two stages. First, the canal shall be dredged so that the flow area of the canal can meet the design requirement. Second, engineering measures shall be determined in accordance with the erosion effect of the dredged canal. It is found that the scouring effect of the canal has been improved obviously after dredging, but it needs a long time to measure and verify the effect.