【作者】 付晓丽；

【导师】 杨纪伟；

【作者基本信息】 河北工程大学 ， 水力学及河流动力学， 2008， 硕士

【摘要】 由于桥梁阻水作用,受河道自然状况、来流条件、桥墩结构、桥址等多方面的影响,桥梁建设对河道的影响作用非常复杂,难以完全从理论上对其进行研究。从目前研究现状来看,对于斜交桥工程后的水流流态、桥墩壅水和冲刷的研究尚不深入,还需对其进行系统的试验和理论分析,而河工模型试验方法是最佳捷径。河工模型试验能够成功地重演天然河流的某些演变过程,并且能够准确的预测和预报修建工程后的河床发展趋势,确定桥前水位壅高和影响范围以及桥墩局部冲刷程度等问题,为河道管理部门和桥渡建设、设计部门提供可靠的依据。本文以某跨河工程为例,进行了河工模型试验。详述了河工模型的设计制作方法,并对多种不同工程方案进行了试验。测量了圆柱型桥墩周围在不同工况下的水流流态、桥前壅水高度和影响范围以及桥墩局部最大冲刷深度。分析比较了圆柱型桥墩在不同墩径和跨度、不同斜交角度等情况下的桥前最大壅水高度、局部最大冲深。通过模型试验结果分析得出:在河湾下游,当流量过程相同时,同一河-桥交角情况下,粗圆柱墩大跨度时桥前壅水高度和墩周冲刷深度大于细圆柱墩小跨径的;对于相同尺寸的桥墩,受桥的走向与河道交角的影响为:河-桥斜交角度越小,工程后产生的水位壅高和冲刷越大,对河床的造床作用越强:另外,对于较小河-桥交角下的研究结果表明,工程的建设减小了由于弯道存在产生的工程断面的左右岸水面比降。鉴于试验结果,建议在桥梁建设中应根据冲深设置桩基埋深,增大安全系数,并对河道下游两岸河堤进行加固防护,确保工程安全运行。同时该试验结果也为其它河工模型的设计提供了重要的参考价值,丰富了桥墩壅水及冲刷的理论研究。更多还原

【Abstract】 Influence of bridge construction on river channel become great complexity due to the effect of river natural statuses,incoming flow conditions,bridge structures,bridge locations,and many other effects,which is difficult to study from theory completely. Judging from the current situation,the research of flow patterns,backwater,and pier scour after the project of the skew bridge was not in-depth,which needs to carry out further systematic experiments as well as theoretical analysis,and the river model test method is the best shortcut.River model test can display the evolution of natural river successfully,and be able to accurately predict the evolution tendency of river bed after the project,ascertain both the level of the backwater and the bridge local scour depth at the same time,which could be a technical support for relevant administration and engineering design.Taking one river model test as an example,this article details its design method, meanwhile various engineering schemes are carried out.In this river model test the flow pattern,the level of the backwater and the bridge local scour depth were measured under different conditions.Then the results of the backwater level and the bridge local scour in different diameter,bridge span and various river-bridge skew angles were compared.Analyzing experimental data of the river model test,some results were as follows. At the downstream of the river bend,when the discharge hydrographs are the same,the level of the backwater and the depth of bridge local scour for the large-span piers are less than the small cylindrical piers with the same river-bridge obliquity.The smaller the obliquity of the river-bridge are,the more serious of the backwater level and the bigger depth of bridge local scour increased by the same piers are,moreover it also had strongly influence on river bed evolution.In addition,the small river-bridge obliquity study showed that the water surface slope of the left and right bank aroused by the existence of the river bend was reduced as the result of construction of project.Given the test results,it is necessary to increase the depth of foundation,enhance the safety factor,and reinforce the embankment at the downstream to ensure the operation of the project safely.In all,this will be an important reference for other river model tests.And these conclusions will also enrich and perfect theoretical results of the backwater and the bridge local scour.更多还原