复线桥区航道的巷道效应分析

Analysis of the laneway effect of pipeline bridge

针对2座桥和3座桥构成的复线桥,利用数学模型,计算了不同桥间距和不同斜流交角情况下复线桥的水流流场,得到了修建复线桥后通航净宽的减小值,提出了计算净宽减小值的公式.分析结果表明,随着桥轴线法线方向与水流方向夹角的增大,通航净宽相应减小,需增大航宽;而桥梁间距与桥梁数目的增加,会使桥洞纵深长度增加,巷道效应更加明显,通航净宽也会增大.故桥洞长度及桥轴线法线方向与水流方向的夹角是影响巷道效应的主要因素.

For the pipeline bridge which is constituted by two and three bridges, mathematical model is used to simulate water field of pipeline bridge at different bridge space and different diagonal angle. In order to obain the reduced net width of navigation after the construction of the pipeline bridge, and then the formula is proposed for calculating the reduced net width. The results show that with the increase of the angle between normal direction of bridge axis and the direction of flow, the net width of the navigation decreased, the width of navigation is needed to be increased. The increase in the number of bridges and bridge spacing will be added to the vertical length, which can results in laneway effect more obviously, the width of navigation is also needed to be increased. So,the length of bridge hole and the angle between the direction of flow and bridge axis normal are main factors for affecting the laneway effect.