水力学方法估算大桥对河道防洪的影响

 提出了估算大桥对河道防洪影响的水力学方法，采用这一方法，可以在河道地形和水文资料缺乏的情况下，估算出中、小型河道建桥后桥址上游水位壅高值和壅水范围。具体水力学方法包括：断面流量模数法、宽顶堰淹没出流法、局部水头损失法和恒定渐变流法。应用这些方法，成功地进行了洪湖市汉洪公路新滩东荆河大桥对桥址上游河道防洪影响的计算分析。

Hydraulic Methods for Estimating Effect of Bridge on Flood Control of River Channel

Hydraulic methods are presented in this paper for estimating the effect of bridge on flood control of river channels. Under condition of lack of topographic and hydrographic data, the values and scopes of back up water level at upper reaches of bridge, built on medium of small size rivers, can be evaluated by using the methods. The specific methods include the method of cross section modulus of dischange, method of submerged broad crest weir outflow, method of local head loss and method of gradually varied steady flow. Applying these methods, calculations and analyses of the effect of the Dongjinghe Bridge, which is located across Han Hong road, Xintan town, Honghu city, on flood control of upper river channels are implemented successfully.