【作者】 翁效林；

【导师】 谢永利；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2009， 博士

【摘要】 高速公路拓宽路基的差异沉降是难以避免的，如何采取合理措施控制新老路基差异沉降是设计和施工中的关键问题。针对拓宽工程现有新老路堤差异沉降控制措施，以处治手段消化新老路基不均匀沉降的能力作为一条主线索，以变形协调和控制作为主要目标，通过有限元仿真分析、土工离心模型试验、设计优化及工程实例观测分析，开展了拓宽工程路基差异沉降控制技术的研究。对有限元分析软件MARC进行二次开发，研编了模拟地基初始应力其释放、脱空单元处理、等厚接触面单元等用户子程序，提高了数值分析的针对性和可靠性。通过建立拓宽工程沥青混凝土面层和半刚性基层结构层底脱空计算模型，利用数值分析方法提出新老路基差异沉降的基本控制标准。以此为标准，分析新老路基的路基和地基的沉降变形特征，研究拓宽路基拼接带常用处治措施适应能力大小，研究结果表明加筋处治效果存在一定的局限性，特别对于深厚软弱地基，单一的路基加筋处治不能有效解决新老路基差异沉降差所带来的工程难题。建立地基沉降计算简化模式，利用数值分析方法对拓宽路基拼接带加筋处治技术的筋材铺设层位、铺设层数、搭接长度进行设计优化；对预应力管桩复合地基的桩体模量、桩体长度、置换率、垫层模量、桩帽与桩体等效半径比以及管桩处理范围、布置方式等因素对拓宽路堤荷载下复合地基沉降特性的影响进行了数值分析。分析得出了拓宽工程路基拼接带加筋处治和预应力管桩复合地基处治优化设计参数，并基于分析结果提出了优化设计措施。在土工型离心机上安装加载装置和位移、应力量测系统，建立与实际应力相符的土工离心试验模型，研究了新老路基拼接技术及管桩复合地基处治技术对于拓宽路基差异沉降变形的改善控制作用，得出了拓宽工程新老路基变形性状和差异沉降处治技术的处治效果及作用机理。通过数值分析，结合预应力管桩桩体特殊的工作机理，提出拓宽路基荷载下的管桩复合地基沉降变形计算方法，并根据优化设计研究结果，对本文提出的计算方法进行系数修正。结合郑州至洛阳高速公路改扩建工程施工现场试验段观测，验证了管桩复合地基沉降计算方法的准确性，论证了本文关于新老路基差异沉降控制处治技术研究的合理性。更多还原

【Abstract】 In freeway widening, sub-grade difference settlement is inevitable. How to take action to reduce the differential settlement between new and old ground becomes the key problem of freeway design and construction. Against the existing control measures of difference settlement in widening project, the harmony and control of sub-grade deformation is the important objective with the clue of the capacity to digest treating differential settlement of new and old ground. Through the finite element simulation analysis、geotechnical engineering centrifuge test、design optimization and observational analysis of engineering example, this dissertation studies on the control technology of differential settlement between the new and old ground.Based on the Visual-Fortran flat, the dissertation does the second development of the large common finite element MARC programme using finite element method and geotechnical theory. The subroutines is programmed including initial and release stress subroutine, void element disposal subroutine, motion load subroutine, changing parameter nonlinear elasticity model subroutine, three-dimensional and contact interface element subroutine, and so on. This dissertation establishes computation model of widening the bottom of asphalt concrete road surface, and puts forward the control standard of differential settlement between new and old ground using numerical analysis method. Take this as the standard, this dissertation analyzes the settlement and deformation behavior of the new and old ground, studies on the adaptiveness of treatment measure in convergence zone of widening sub-grade. The result indicated that reinforcement treatment effect is limitation, especially for the deep weak sub-grade, the reinforcement treatment cannot effectively solve difficult engineering problem, taken by differential settlement between new and old ground.This dissertation establishes computation simplification pattern of ground settlement, designs the laying down position, the layer number, the overlap length of the reinforcement treatment technology by numerical analysis method. This dissertation analysis the influence of pile modulus、pile length and exchange rate of pre-stressed pipe pile compound foundation on the settlement characteristic of compound foundation. The result shows that the piles’ space、pile stiffness、cushion compression modulus、treatment scope and arrangement way of pipe pile compound foundation has influences on differential settlement between new and old ground. Therefore, this dissertation obtains optimization design parameter about reinforcement treatment of widening sub-grade convergence zone and the treatment of pre-stressed pipe pile compound foundation, and puts forward the optimization design measures.This dissertation installs load device、stress and displacement measurement system using medium centrifuge equipment. This dissertation simulates the improvement of the deformation and treatment technology to sub-grade settlement、stress concentration and overall stability in sub-grade widening.Base on numerical analysis and the centrifuge model test, this dissertation put forward reasonable calculation methods of pipe pile foundation settlement by the stress and deformation of the compound foundation pile-soil, combined with mechanism of the pre-stressed pipe pile. Through observing the application of the pipe pile compound ground in Zhengzhou-Luoyang Expressway Extension Project test section, this dissertation proves the veracity of the calculation methods about pipe pile foundation settlement, and proves the rationality of the control technology of differential settlement between the new and old ground.更多还原