沿河公路桥对山区河道壅水长度的影响

Effect of highway bridge along river on backwater length of channels in mountainous areas

随着中国西部在山区河流密集的地方修筑公路的持续推进,研究沿河公路桥与山区河道水力学间的关系变得越来越迫切.以四川省阿坝州沙坝大桥为例,利用Hec-Ras模型改进特征参数的设置分析了沿河公路桥对山区河道壅水长度的影响规律,基于跨河桥壅水长度的一般公式引入了单独壅高和附加壅高的概念,并提出了沿河公路桥的壅水长度公式.从公式中可以看出沿河公路桥对山区河道的影响程度和影响范围通常比跨河桥更大,约为桥长的2倍以上,壅水高度从桥位区间的下游至上游几乎呈倍数增长.

With the continuous development of highway construction in mountainous areas where rivers are dense,it becomes more and more urgent to study the relationship between highway bridges along rivers and river hydraulics in mountainous areas.Taking Shaba Bridge in Aba Prefecture of Sichuan Province for example,this paper uses Hec-Ras model to improve the setting of characteristic parameters to analyze the influence of highway bridges along rivers on backwater length of mountain rivers.Based on the general formula of backwater length of river-crossing bridges,the concepts of individual backwater height and additional backwater height are introduced;and the highway along rivers is put forward.The formula of backwater length of hibway bridge is put forward.It can be seen from the formula that the influence degree and scope of highway bridges along rivers on mountainous rivers are usually larger than that of cross river bridges,which are more than twice the length of bridges;and the backwater height increases almost exponentially from the downstream to the upstream of the bridge location.