【作者】 王富江；

【导师】 张建经；

【作者基本信息】 西南交通大学 ， 岩土工程， 2013， 硕士

【摘要】 如何控制工后沉降和提高施工速度是在软基上修建高速铁(公)路时面临的两大技术难题。桩-网复合地基的推出为解决快速施工条件下的路基工后沉降控制问题提供了新的途径。目前该方法在工程上已经有一定应用并取得较好的效果,但由于桩-网复合地基的工作机理十分复杂,其理论研究远远落后于工程应用,在很大程度上制约了其推广应用。本文首先梳理了桩-网复合地基的基本理论,对其加固机理以及土拱效应和薄膜张拉效应作了简要介绍。然后对路堤-桩-网复合地基体系作适当简化,通过Plaxis2D建立二维路堤模型对路堤下桩-网复合地基的各部分力学性状以及复合地基的作用机理进行了有限元分析,并详细分析了软土层模量、下卧层模量、土工格栅抗拉刚度、CFG桩体模量、桩长及桩间距布置等影响因素对复合地基承载特性和各部分力学性状的影响规律。最后利用有限元方法对路堤作用下桩-网复合地基的变形,包括侧向变形和沉降规律及其影响因素作了详细的研究,并针对工程应用中的一些问题给出了具体建议。本文在研究过程中分别考虑了路堤填筑阶段和固结阶段桩-网复合地基的不同力学性状及变形特点。更多还原

【Abstract】 Residual settlement control and construction speed improvement are two technology difficulties if high speed railway and express road are built in soft soil.There emerged pile-net composite foundation, which a new way to solve stability and residual settlement control, and it is used in construetion with effective performance.But the working mechanism of pile-net composite foundation is very complex, the theoretical research is far behind the engineering practice, to some extent limited its popularization and application.At first, this paper combs the basic theory of pile-net composite foundation, briefly introduces the reinforcement mechanism and the soil arching effect and membrane effect.And then appropriately simplify the embankment-pile-net composite foundation system, establish a two-dimensional model of the composite foundation by Plaxis2D, do finite element analysis about mechanical behaviors and mechanism of portions of pile-net composite foundation under embankment. A detailed analysis of the soft soil layer moduli, crouching modulus, geotechnical grid under tensile stiffness, modulus, length of CFG pile and pile spacing, layout and other influence factors on bearing capacity of composite Foundation and the law of some mechanical properties.Finally using finite element method detailed study of the embankment pile under-net composite foundation deformation, including lateral deformation and settlement rules and its influencing factors, made specific recommendations for some of the problems of engineering applications.Based on the study were considered in the process of the embankment filling and consolidation phase pile-net composite foundation of different mechanical properties and deformation characteristics.更多还原