压力流条件下的推理公式法研究

Reasoning Formula under Pressure Flow Conditions

在沿海或地势低洼地区,很容易出现管道出水口的内管顶高程低于该处设计洪水位的情况。为了弥补现行的恒定流推理公式法仅依赖均匀流条件的缺陷,采用了一种不再用管底坡降替代水力坡降计算流速,而是直接用水力坡降求解恒定流推理公式的方法,使恒定流推理公式法也能精确计算在压力流条件下的雨水设计流量;同时,该方法还具有同数学模型一样能反映管道沿途各检查井水位的功能,有利于判断管道是否会发生漫溢和地面积水。

In coastal region or low-lying area, it is very common that the crest elevation of the pipe outlet is lower than the designed flood level. However, the current reasoning formula of steady flow is based on the uniform flow. To overcome the limitation, a new method was proposed by using the hydraulic gradient to resolve reasoning formula of steady flow, instead of the gradient at the bottom of pipe. The new method could accurately calculate the design flow of rainwater under pressure flow conditions. Meanwhile, similar to the mathematical model, the proposed method could demonstrate the water level of the inspection wells along the pipeline and determine the presence of the overflow or surface ponding.