秦淮河地铁桥物理模型试验研究

秦淮河地铁桥临近秦淮河大桥,主桥墩采用双壁墩形式,由于桥墩壅水与桥墩形状、桥墩尺寸、桥墩布置形式、阻水面积比、河道水流情况等诸多条件有关,而经验公式往往仅考虑其中的几个因素,没有普遍适用性.应用平面比尺为1∶100,垂直比尺为1∶50的变态物理模型试验,研究了地铁秦淮河大桥的桥墩壅水、河道水流流速、水面线、流态等内容.结果表明:河道水面线可分为3段,桥前壅水最大为0.02 m,壅水长度为桥梁上游500 m,墩间流速最大增加0.29 m/s.

Physical model test of the Qinhuai River metro bridge

The metro bridge is close to the Tianyuanzhonglu road bridge,and has two main double wall piers.The backwater of bridge piers is related with piers′ shape,size,configuration,river flow and so on.Empirical formulas for backwater are not universal.A distorted physical model with a scale of 1100 horizontally and 150 vertically is built for the study.This test studies the backwater,flow velocity,water surface curve and flow pattern near the bridges.The results show that water surface profile can be divided into three sections.The maximum backwater level is 0.02 m,and the length of backwater is 500 m in the upper reaches of the bridge.The maximum increase of flow velocity between piers is 0.29 m/s.