公路桥头跳车问题探讨
揭阳市公路局直属分局  黄泽冰
【摘 要】 本文从路基沉降、施工方法和结构体系上对桥头跳车病害进行原因分析，探讨提出减少病害防治措施。

【关键词】 桥头跳车原因分析防治措施　

1 前言

   随着经济发展，公路建设取得了突飞猛进成绩，投入营运高等级公路越来越多，但从使用情况上看，出现了桥头跳车这个较为普遍问题，尤其在一些软土地基地方更为严重，给养护部门带来了很大困难。如揭阳去年建成的榕华大桥，刚投入使用就出现严重桥头跳车现象，高差达５-８ｃm，使桥头接缝，在砼板遭到破坏，影响了行车舒适与安全。因此，探讨桥头跳车现象，对此进行综合分析，对我们养护部门有较现实意义。

２ 桥头跳车原因分析

２．１ 地基沉陷

   土质不良，由此产生沉陷是桥头跳车的主要原因。桥涵通常位于沟壑地方，地下水位较高，在南方地带多有软土，此类土天然含水量大于液限，天然孔隙比大，常含有机质，压缩性高，抗剪强度低，一旦受到扰动，天然结构易受破坏，强度便显著降低，桥头路基填筑高度较大，产生基底应力相对较大，在车辆荷载作用下，更容易引起地基沉陷，且变形稳定历时往往持续数年乃至数十年。就是在一些稳定地基，在外荷作用下，也无可避免出现这个问题。

２．２ 压缩沉降

   台后填料一般为渗透性材料，存在着多孔隙，加上施工时受施工作业方面影响，压实机具不能过分靠近接触台背，不能将填料颗粒间孔隙完全消除，在车辆荷载和自身重力作用下，填料迅速压缩，孔隙率降低，便在短时间内产生压缩沉降，造成跳车。在工程实践中，就是施工时工序符合要求，压实度达到要求，但台后填土较高，随着时间推移，也会产
Highway Bump Discussion
Jieyang City Highway Bureau directly under the branch huangze ice
Abstract In this paper, Settlement, construction methods and structural systems were on the Causes of Disease Bump, the reduction of disease control measures.

Key words Bump Causes Prevention

1 Introduction

   With economic development, road construction has made rapid results, more and more highway put into operation, but the use of point of view, there Bump the more common problem, particularly more serious in some soft place, to the maintenance department is a big difficulty. Such as Banyan Jieyang China last year built the bridge, just seriously put into use on the bridge of bridge, the height difference up to 5-8cm, to bridge joints, the concrete panels were damaged, affecting the ride comfort and security. Therefore, the phenomenon of Bump, this comprehensive analysis, we have more practical significance conservation department.

2 Analysis of Bump

2.1 Ground subsidence

   Poor soil, the resulting subsidence is the main reason for Bump. Bridge is usually located in ravines, water tables are high, many areas in the south have soft soil, such soil moisture content is greater than liquid limit, the natural void ratio, often with organic matter, high compressibility, shear strength and low, in the event of disturbance, natural structure sensitive, the intensity will be significantly lower, larger bridge roadbed filling height, resulting in relatively large base stress, the vehicle load, the more likely to cause ground subsidence, and deformation are stable for several years and even took a few years. Some stability is the foundation, under the action of external load, but also inevitably have such problems.

2.2 compression settlement

   After the filling station is generally permeable material, there are porous, with construction aspects of construction operations by the effects of compaction equipment can not be too close contact with Taiwan back, can not completely eliminate the pore filler particles in the vehicle load and own weight under rapid compression packing, porosity reduction, will be produced in a short time compression settlement, resulting in jumping. In engineering practice, is the construction process to meet the requirements, meet the required degree of compaction, but after the filling station higher over time, will produce