路桥结合部位水毁规律模型试验研究

Model Test Research on Flood Damage Rule of Highway-bridge Binding Site

为揭示平原河段路桥结合部位水毁规律,开展路桥结合部位水毁现场勘查和10种工况的室内模型试验,研究桥台尺寸、阻水比、端头形状、坡比、挑角以及水流冲刷时间和水流流速等影响因素下的水毁规律.研究表明,路桥结合部位是公路桥梁工程水毁易发部位,具有显著的区域性特征;模型迎水面水流流速及其冲刷时间、水流冲刷淘空最大深度、水毁堆积物横向扩散范围及其竖向堆积厚度,在一定程度上反映了路桥结合部位水毁程度和变化规律;桥台长度越短则其安全性越高,水位越高则桥台水毁越强烈,桥台端头为圆弧状能有效降低其水毁程度;有一定坡度的桥台削弱了水流与其迎水面的接触作用力,从而降低了水毁程度;桥台挑角不同会产生不同的水毁破坏现象;水流冲刷时间越长、水流流速越大,桥台水毁越显著.试验结果与现场勘查实际情况相吻合,研究结果在路桥结合部位水毁防治方面有一定的参考意义和应用价值.

In order to reveal the rule of flood damage in the joint position of road and bridge in the plain rivers,develop site survey of flood damage at the joint position of road and bridge and indoor model test of 10 working conditions,the article studies the flood damage law under the influencing factors of abutment dimensions,water resistance ratio,end shape,slope ratio,bucket angle,flow scouring time and flow velocity.The result shows that,the combination position of road and bridge is liable to be damaged by flood in highway and bridge engineering with distinct regional characteristics;the flow velocity and scour time of the model facing the water surface,maximum depth of scouring and emptying,horizontal diffusion range of destroyed deposits and their vertical stacking thickness reflect,to some extent,the degree of flood damage and the changing law at the joint position of road and bridge;the shorter the abutment length is,the higher the safety will be,the higher the water level becomes,the stronger the water damage of abutment will be,and the end of abutment with a circular arc can effectively reduce the damage degree of abutment;the abutment with a certain slope weakens the contact force between water flow and its facing surface and reduces the degree of water damage accordingly;Abutment with different angles will cause different damaging phenomena;the longer the scouring time is and the higher the flow velocity turns,the more significant the abutment water will damage.The results of model test match the actual situation of site survey,and the research results have certain reference significance and application value in prevention and treatment of road and bridge joint site.