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大量桥墩的下部具有扩大的重力式基础或桩基承台基础。可是,现有的局部冲刷计算方法,对这种结构形式的影响考虑得不够正确,因而常常造成错误的局部冲刷计算深度。变截面桥墩的计算宽度系采用整个水深中的平均宽度。但是,对局部冲刷有影响的桥墩宽度仅仅是自河底算起的1/2水深内的桥墩部分。众所周知,局部冲刷是由于障碍物压缩水流后引起水流发生剧烈变形而造成的。比较低层层的水流部份形成指向床面的弯曲水流,在接近床面区域内产生流速的加大和紊动的增强,并且具有漩涡结构。
The lower part of a large number of piers has an enlarged foundation of gravity or pile foundation. However, the current method of local erosion calculation, which takes into account the effect of this type of structure, is not properly considered and often results in erroneous calculation of the local erosion. The calculated width of the variable section piers is based on the average width of the entire depth. However, the width of the piers that affect partial scouring is only the part of the piers within 1/2 of the water depth from the bottom of the river. As we all know, local erosion is due to obstructions caused by the flow of water flow caused severe deformation. The lower water flow part forms a curved flow of water directed towards the bed surface, resulting in an increase in flow velocity and turbulence near the bed surface, with a vortex structure.