【作者】 李中国；

【导师】 赵有明； 刘国楠；

【作者基本信息】 中国铁道科学研究院 ， 岩土工程， 2011， 博士

【摘要】 锚索桩板墙是一种新型支挡结构,主要由桩、锚索和挡土板构成。与悬臂式桩板墙相比,桩的受力状态得到改善,应用高度明显提高,具有显著的技术经济优势,已经在公路、铁路及水利建设项目中得到了较广泛的应用。但是目前对该结构的研究远落后于工程应用,锚索桩板墙应用不当造成破坏的现象时有发生。在此背景下,本文结合现场试验对高填方锚索桩板墙结构进行了系统的研究,深入分析了该结构的工作机理及受力特性,构建了结构-土的相互作用力学模型并提出了更加合理、完善的设计计算方法。本文取得的研究成果对该类结构的进一步发展和推广应用有重要的理论和工程实际意义。本文首先对锚索桩板墙结构进行了简要的分析,阐述了锚索桩板墙的各组成部分的工作特点。通过分析发现锚索桩板墙结构的最终的内力及变形与施工过程有着密切的关系,不同的工况将导致不同的结构的内力及变形。基于结构-土的相互作用分析,建立了各施工工况的锚索桩板墙的力学计算模型并提出了新的锚索桩板墙的计算方法——“增量法”,该方法可计算各工况的结构反应。分析了两个不同地层条件下的锚索桩板墙现场试验结果,研究了结构受力性状随施工过程的变化规律。着重分析了两个试验工点的结构内力和变形随着填土过程和锚索张拉施工的变化规律,总结了锚索、桩和填土之间的相互作用关系。锚索张拉工况的现场试验结果与弹性地基梁计算结果吻合较好,验证了在锚索张拉时桩土系统符合竖向弹性地基梁模型的特性。将两个现场试验的结果对比,总结了不同的地层条件下结构的不同反应特性。论文采用ABAQUS有限元软件建立了二维计算模型并对锚索桩板墙试验工点的的施工过程进行了模拟分析,研究了不同施工阶段锚索桩板墙结构和填土的应力状态的变化及变形规律。模拟结果表明:在锚索张拉后,改变了填土的应力状态,限制了填土内塑性区的持续发展;锚索张拉锁定后的填土塑性区以新的填土面开始发展。论文根据现场试验及数值分析成果,提出了土压力在各工况的分布模式并给出了完整的增量法计算过程。采用增量法对试验工点进行了反算,反算结果与试验结果吻合较好,证明了本文提出方法的合理性。关于锚索拉力设计值的确定,建议根据不同地层条件以静止土压力的(0.4~0.7)倍取值。最后,根据不同地层的锚索桩板墙的受力特性,提出了不同地层条件下的高填方锚索桩板墙“桩-土刚度匹配”的设计原则,即当地层刚度较小和较大时分别采用“强锚弱桩”和“强桩弱锚”的桩锚搭配关系。总结归纳了锚索桩板墙的设计流程及步骤。列举了某高速公路的高填方路基锚索桩板墙应用实例的以供参考,同时对某个锚索桩板墙的破坏原因进行分析,总结了经验及设计注意事项。更多还原

【Abstract】 Anchored soldier pile and lagging wall consisting of pile, ground anchor and concrete lagging is a new type of retaining wall to retaining high fill embankment. Compared to cantilever soldier pile and lagging wall, load bearing of pile is greatly improved and the wall became higher than other type wall for the usage of anchor. With significant technical and economic advantages, this structure has been widely used in freeway, rail way construction and water conservancy project. But the theoretical research of the structure is far behind of its engineering application, Anchored soldier pile and lagging wall damage occurs at times for improper application. On this background,a systematic study of the structure was made in this paper . The working mechanism and the mechanical properties of this structure were studied. Then the mechanical model was erected based on structure-soil interaction and a more rational, suitable calculation method was proposed. The achievements of the study on the structure have significant theoretical and practical value for further application of the wall in the future.First of all, through briefly analysis of the structure, the working characteristics of the each component of the structure was discussed. It was recognized that the final inner force and displacement was influenced by the process of the construction, namely the different case conditions would result in different inner force and displacement. Based on the soil-structure interaction, the mechanical calculation model of different construction stage was established which can calculate the change of structural reaction. The new Calculation method named "incremental method" was proposed.The results of two filed test with different geologic conditions were analyzed and the characters of the structure reaction during the construction process was studied. Consequently, the change law of the pile inner force, displacement and anchor force was emphatically analyzed. The results of field tests also demonstrated that final inner force and deformation of piles was closely related with construction processes. It was confirmed that the pile-soil system was in good accordance with beam on vertical elastic Foundation model characteristics by the conformance between datum from test and results from calculation of model of the beam on elastic Foundation when anchor stressing. Results of the two field test demonstrated that the structure under different geologic conditions have different behavior.The 2D analysis of one of field tests work was conducted by ABAQUS FEM software and its construction processes was simulated to study the reactions of the structure and backfill. The simulation results showed that the stress state of backfill was changed and its sustainable development of the plastic zone of the backfill was constrained once the anchor was locked-off. The development of new plastic zone of subsequent filling would start at the locked-off plane.On the basis of the field test and numerical analysis conclusions,the distribution of the earth pressure in each stage was put forward and the complete calculation process of the incremental method was given. Then one of field test wall was calculated by the incremental method and the good agreement between the tests results and calculation result proved the correctness of the incremental method proposed in this paper. For the value of the anchor force, it was suggested that the total pull force can be determined by (0.4~0.7) E0 according to different strata conditions. E0 stands for the general rest earth pressure.Finally, according to mechanical characteristics of different strata conditions, the basic design principles of the wall were presented, called "pile-soil stiffness matching" design method. When the stiffness of the strata where the pile was embedded is weak, the weak stiffness of the pile and more anchors should be taken. Otherwise, the strong pile should be designed. Furthermore the design process and steps of anchored soldier pile and lagging wall was summarized and an application of the wall for high fill embankment in some freeway was introduced for future reference as well as a damaged anchored soldier pile was analyzed. Lessons and the points for attention to be drawn for the future design.更多还原