【作者】 丁静声；

【导师】 陈谦应；

【作者基本信息】 重庆交通学院 ， 道路与铁道工程， 2004， 硕士

【摘要】 随着我国国民经济的迅速发展,近年来我国公路建设的里程开始迅猛增长。从目前已建成公路的使用情况来看,存在着一些通病,其中一个较为普遍存在的就是桥头跳车现象。桥头跳车是由于桥台回填土的固结沉降、次固结沉降、地基沉降引起台背非均匀沉降进而导致过往高速车辆剧烈跳动的一种现象。治理桥头跳车的方法很多,但采用设置桥头搭板无疑是最常用的方法之一。设置桥头搭板简单实用,其目的是将台堤衔接处突变的错台高差分散到搭板的两端,从而改善桥头行车条件。桥头搭板处理目前尚没有明确规定。实践中一般桥头搭板不作专项设计,且理论依据不甚合理,如搭板长度计算采用桥头容许变坡差和沉降量确定,没有考虑路堤填土高度、桥台形式及填土性质,所以有时会出现搭板脱空、断裂或过短而未能彻底消除跳车现象,从而给道路桥梁的使用带来影响。所以对搭板的设计有待进一步作深入的研究。本文在对桥头跳车成因和桥头搭板设计影响因素作了详细的分析基础上,运用弹性地基梁理论和有限元数值计算方法,对桥头搭板在近台端不脱空和脱空时,在不同的地基模量及不同的搭板长度,搭板任意截面的地基反力、内力(剪力和弯距)及挠度大小进行计算,得出了一些有意义的结论。本文的计算成果将有助于工程上结合实际情况正确确定搭板的合理尺寸,从而消除桥头跳车隐患。更多还原

【Abstract】 Along with the quick development of the economy, the mileage of our national highways is increasing fast in recent years. However, there are some common faults in these constructed highways, of which the bumping at the bridge head is universal and typical. The bumping at the bridge head is caused by the consolidation settlement and the secondary consolidation settlement of the fill-back soil at bridge abutments and the settlement of the foundation of bridge approaches. When the vehicle cross fast the transition segment ,they will bump violently.There are many ways to deal with the bridge head bump ,but set the approach slap is undoubtedly the most common way. Setting approach slap is easy and useful. The purpose of that is to disperse the mutational difference of elevation of the faulted slabs in the joining place of the abutment bank to the bridging slab’s two ends, so as to develop the traffic condition. However, there is no clear prescription of the disposal of the approach slap. In the practice we have no special design of the approach slap , and the theoretical thereunder is not so reasonable. For example, when calculate the length of the approach slap, we adopt the permission differential change slap and settlement, without considering the height of road embankment filling , the form of abutment and the properties of the filling sort, so sometimes it is hard to eliminate the bridge head bump completely because of the disjoint, rupture or overshort of the approach slap, influencing the use of the road and bridge. So we should make deep research of the approach slap design in the step.On the basis of detail analyzing the cause and influence factors of the approach slap design, this paper which utilize the flexible ground beam theory and finite element numerical calculation method to calculate the ground reaction、internal force (shear force ,bending moment) and bending deflection, in each condition of disjoint and undisjoint of the approach slap near the abutment end, with the different ground module and length of the approach slap, achieves some valuable conclusions. What’s more, the calculation product will benefit for the project to make the reasonable size of the approach slap, so as to eliminate the hidden trouble of the bridge head bump.更多还原