铁路斜交桥对河道行洪的影响及对策

一些桥梁受地形和线路的制约,桥位不得不采取与河渠斜交的穿越方式,造成桥墩较大的阻水作用.采用经验公式计算与数值模拟两种方法对某铁路斜交桥的行洪影响进行分析,研究了不同洪水条件下的壅水高度与范围、桥梁一般冲刷与局部冲刷深度、桥梁对行洪断面的阻水比.研究表明:桥梁设计基本满足要求,建桥后河势变化不大,但行洪断面的阻水比偏大.拟建桥采用与既有桥对孔布置,可以减小双桥对行洪的阻滞影响.提出了疏浚开挖边滩来补偿工程占用河槽行洪面积,经计算分析该方案,可以有效减小阻水比与壅水高度,减轻工程局部冲刷,有利于区域行洪安全.

Impact of the skew bridge on the river flood and countermeasures

Restricted by topographic and route conditions,some bridges have to be constructed across the river channels by the way of skew,which results in greater resistance effects on the pier.The original text adopts two ways of empirical formula and numerical simulation to analyze the impact of the skew bridge on the floods.The backwater height and range in different flood conditions and the scour depth of the general scour and local scour are confirmed,and the water-blocking ratio of the bridge to the over-current section is also analyzed.The analysis of the backwater height,range and bridge scour shows bridge design meets the requirements basically,and the river regime doesn′t change much after bridge construction;but the water-blocking ratio of the over-current section is too large.The proposed bridge uses on-the-hole layout with the existing bridge,which has little effect on the over-current and regime of the proposed bridge,and can reduce the flood retarding effect of the two bridges.The author proposes excavation of the beach to compensate the flood area occupied by the project.By calculation and analysis of the program,it can reduce the water-blocking ratio and the backwater height effectively,and mitigate local scour,which is conducive to regional flood control.