自流压力输水管路保水堰最小安全超高分析

Analysis on minimum superelevation of retaining weir in long distance water transfer conduit system

自流压力输水管路的保水堰是保证稳定供水和安全运行的重要工程措施。本文把调节池-输水管道-保水堰作为一个水力系统,分析保水堰的工作原理和运行特点,建立动态水流的数值计算模型。利用试验数据对计算模型进行验证后,采用数值方法对保水堰的水流特性进行模拟。结果表明,当输水系统停水时,长管道水流的惯性力作用可能引起调节池的水位跌落和波动,为了防止进水口发生水体脱空现象,保水堰的最小安全超高需大于上游突然停水时调节池的最大跌落深度,从而建立了保水堰安全超高的估算公式。

Retaining weir is a kind of important structure for ensuring the stability and safely operation of gravity long distance water transfer conduit system. In this paper the regulation pool, conduit and retaining weir are regarded as an integrated system to analyze the working principle and operation characteristics of a retaining weir and establish the numerical model for calculate the hydraulic transient probably occured to the system. The validity of the model is verified by physical model test. On this basis, the model is applied to further investigate the hydraulic characteristics of a retaining weir. It is found that sharply drop down and consequent fluctuation of water level will occur to the regulation pool due to inertia force when the water transfer system suddenly stop working. For ensuring the safely operation of conduit system, a minimum superelevation relative to the top of the inlet must be adopted. The formula for calculating the superelevation is suggested.