高速公路单侧拓宽工程新老路基差异沉降的研究

发布时间：2019-05-16 17:17

【摘要】：为满足高速公路日益增长的交通量需求,现阶段常采取的措施是对老高速公路进行改扩建,一般是在路基一侧或两侧直接进行拼接拓宽。我国已建或计划建设的高速公路拓宽工程大多以双侧拓宽为主且相关研究比较深入,然而,单侧拓宽工程及其相关理论研究、工程特性分析较少。为全面深入地了解高速公路单侧拓宽工程,本文在分析国内外研究现状的基础上,运用ABAQUS有限元软件研究分析单侧拓宽工程中新老路基的沉降变形特性,为实施工程技术提供理论依据。首先,对拓宽工程中路基常出现的病害及沉降变形机理进行分析,总结单侧拓宽情况下新路基产生附加应力及新老路基差异沉降的计算方法。然后,对高速公路单侧拓宽路基进行深入分析,运用ABAQUS有限元软件建立单侧拓宽路基的数值模型,进行有限元数值模拟,分析在新路基填筑施工过程中老路基的沉降变形及工后几年不同时期新老路基之间的差异沉降变化特性。通过建立不同拓宽形式的路基数值模型,重点分析单侧拓宽路基与双侧拓宽路基在沉降特性方面的差异;针对单侧拓宽路基模型,探讨拓宽路基宽度、路基设计高度、新老路基模量差异、路基填料强度等不同因素对路基差异沉降的影响,从而对新老路基差异沉降的产生及影响因素有全面的认识。最后,从地基和路基两个方面考虑采取控制单侧拓宽工程路基差异沉降的技术措施,地基处治措施主要包括采用轻质路堤填料及复合地基法,路基处治措施主要包括老路削坡及开挖台阶、应用土工合成材料、提高路堤压实度等,并分析这些措施的处治效果及设计要点,为应对单侧拓宽工程中控制差异沉降采取措施提供参考依据。
[Abstract]:In order to meet the increasing demand for traffic volume of expressway, the measures often taken at this stage are to reconstruct and expand the old highway, which is usually spliced and broadened directly on one or both sides of the roadbed. Most of the highway widening projects built or planned in our country are mainly bilateral widening and the related research is more in-depth. However, the unilateral widening project and its related theoretical research have little analysis of engineering characteristics. In order to understand the unilateral widening project of expressway in an all-round way, on the basis of analyzing the present research situation at home and abroad, this paper uses ABAQUS finite element software to study and analyze the settlement and deformation characteristics of the new and old roadbed in the unilateral widening project. It provides a theoretical basis for the implementation of engineering technology. Firstly, the common diseases and settlement deformation mechanism of subgrade in widening project are analyzed, and the calculation methods of additional stress and differential settlement of new subgrade and old subgrade under unilateral widening are summarized. Then, the unilateral widening subgrade of expressway is deeply analyzed, and the numerical model of unilateral widening subgrade is established by using ABAQUS finite element software, and the finite element numerical simulation is carried out. This paper analyzes the settlement deformation of the old subgrade in the process of new subgrade filling construction and the characteristics of the difference settlement between the new and old roadbed in different periods after construction. By establishing the numerical models of different widening forms of subgrade, the difference of settlement characteristics between unilateral widening subgrade and bilateral widening subgrade is analyzed. Aiming at the unilateral widening subgrade model, this paper discusses the influence of different factors, such as widening subgrade width, subgrade design height, new and old subgrade modulus difference, subgrade filling strength and so on, on the differential settlement of subgrade. Thus, there is a comprehensive understanding of the emergence and influencing factors of the differential settlement of the new and old roadbed. Finally, the technical measures to control the differential settlement of subgrade in unilateral widening project are considered from two aspects of foundation and subgrade. The measures of foundation treatment mainly include light embankment filling and composite foundation method. The measures of subgrade treatment mainly include cutting slope and excavation step of old road, applying geosynthetics to improve compaction degree of embankment, etc., and analyze the treatment effect and design essentials of these measures. It provides a reference for the control of differential settlement in unilateral widening project.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.1

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