箱式涵洞侧翻式拍门过流计算的模型与应用

The Model and Application of Overflow Calculation of Box Culvert Flap Door

侧翻式拍门因水力损失小、过流能力大,在排水涵洞工程中的应用越来越广泛,但目前为止尚未有设计规范和书籍明确其水力计算公式,造成设计工作者无据可依。文章通过对拍门进行受力分析,推导了箱式涵洞侧翻式拍门的开启角计算公式,还进行了过流分析,给出了适用于箱式涵洞侧翻式拍门的过流计算公式,并以实际工程为例进行了过流计算和分析。结果表明:下游水位一定时,拍门的开启角和过流量随着上游水位的逐渐增高而不断增大,但增大的速度逐渐减慢;因安装拍门对上游水位产生的壅高值,随着过流量的增加呈现出先减小后增加的趋势;随着下游水位的逐渐增高,开启拍门所需要的上下游水头差呈减小趋势。

The rollover shutter has been widely used in drainage culvert engineering,because of the small hydraulic loss and large flow capacity.However,there is no design code or book to clarify the hydraulic calculation formula,resulting in no basis for designers.Based on the force analysis of the flap door,the opening angle calculation of the flap door of box culvert is deduced in this paper.The overflow analysis is also carried out,and the formula for calculating the overflow is given.The overcurrent calculation and analysis are carried out by taking the actual project as an example.The results show that when the downstream water level is constant,the opening angle of the door and the flow rate of the gate increase with the upstream water level,but the increasing speed gradually slows down.With the increase of the flow,the opening angle first decreases and then increases.The difference of upstream and downstream water head required to open the flap door tends to decrease.