Numerical Modelingresearch On The Influence Of Sea-crossing Bridge Engineering To River Course Flood Propagation

The traditional river-crossing or sea-crossing bridges are mainly square bri dges,while as a matter of fact,some stream segments are restricted by terrain,hydrologic features,municipal planning and other factors,the bridges in these areas can’t be orthogonal to river,and have to be designed into the form of the skew bridge.In recent years,with the accelerating development of urbaniza tion,the traffic pressure and urban construction intensity are intensified,which making the angle of skew bridge becomes bigger and bigger,even occurring th e form of bridges built along the river.Considering the background of the pro posed sea-crossing bridge which will be built along the Tang River estuary of Qinhuangdao,in this article we construct a two-dimensional hydrodynamic mat hematical model using numerical simulation methods,with the purpose of analy zing the special bridge project which is built along the Tang River estuary and the waterway dredging engineering using numerical simulation analysis method s.The main research results are as follows: First of all,tidal flow mathematical model is established for the bridge engineering area based on the two-dimensional shallow water equations in the way of large and small model nested,after the rati onality is verified,we further establish the mathematical model which applying to the research of cross-sea bridge hydrodynamic characteristics in Hailuo Isla nd.All above results provide technique support for the flood discharge charact eristic research in Tang River.Second ly,we also analyze the hammed water ch aracteristics for the special bridge built along the river,and the results indicate that this kind of bridge can lead to hammed water,but the change of water l evel rise is not that big,and have no serious effects o n the safety of river flo od passing.Desilting work is also simulated because of its significant influence on the safety of flood passing,it turns out that the implementation of the dre dging engineering can effectively reduce the river water level,which can make sure the safety of flood passing.Finally,the flow regime of large and small Tang River is simulated in this article,and we furtherly analyze the cause of r iver bed scour and river maelstrom.In conclusion,d redging engineering has s mall influence on river flow regime,but the establishment of the cross-sea brid ge is the direct cause of large vortex in the river,in addition,Hailuo Island pr oject itself,the number of bridge piers,piers layout situation as well as the br idge site location and other factors also have effects on river flow regime.Wh at’s more,after calculation,maximum erosion depth of the river bed scour which caused by flood passing meets the safe value of buried depth of the special bridge ba sement and has no threat for the bridge itself.