【作者】 孙健；

【导师】 夏柏如；

【作者基本信息】 中国地质大学（北京） ， 地质工程， 2005， 博士

【摘要】 目前,复合地基的理论研究远远落后于复合地基的工程实践,而我国关于复合地基的相关规范由于岩土材料性质的复杂性和变异性,岩土工程边界条件的不确定性等众多影响因素,使得复合地基的设计和施工留有很大的选择和发挥空间,因此,如何提高复合地基的设计计算精度,满足建筑工程对可靠性、安全性及经济性的要求,是岩土工程人员的当务之急,也是复合地基工程的研究目标和方向。有限元等数值方法由于能够建立较为符合实际工程的相应计算模型和边界条件,并且根据求解的精度要求对求解域进行离散,能得到求解域内任意点的应力和变形,所以近年来被越来越多地运用到复杂或重要工程的复合地基分析和研究中,并且得出了许多对实践有指导意义和应用价值的结论。 本文针对高层建筑筒中筒结构的特点,利用ANSYS8.0有限元软件对其箱形基础下CFG桩复合地基进行了三维数值模拟(边界条件参考北京佳程广场CFG桩复合地基工程),通过以下六中不同的情况对高层建筑筒中筒结构箱形基础下CFG桩复合地基的性状做了详细地分析和研究。 1.内外筒基础底板上作用不同荷载的情况 2.内外筒基础底板厚度不同的情况 3.内外筒CFG桩面积置换率不同的情况 4.CFG桩复合地基褥垫层厚度不同的情况 5.内外筒CFG桩桩长不同的情况 6.内筒CFG桩布桩范围向外筒外扩长度不同的情况 在对CFG桩复合地基应力场和位移场的变化规律进行分析后,结合北京佳程广场(地上26层、地下3层)筒中筒结构箱形基础下CFG桩复合地基实际工程进行优化设计,并将设计结果应用于佳程广场的CFG桩复合地基实际工程中。在佳程广场施工阶段,对天然地基、CFG桩单桩、CFG桩复合地基的承载力以及CFG桩土应力比做了现场静载试验,且在主体结构加荷的各个阶段,对基础底板不同更多还原

【Abstract】 Theory analysis of composite subgrade has got behind practice engineering of it in recent years. In correlation code, design and construction of composite subgrade have actual being unsureness for complex of geotechnical conditions. As a technician of geotechnical engineering, what he need is accuracy of design as well as reliability、 safety and economy of build engineering. Method of FEM has been found application in practice engineering for which can erect model of calculation by specially boundary conditions and obtain exact explain.Through established a three-dimension model, this paper makes use of ANSYS FEM software analysis and study of the characteristics of CFG-pile composite subgrade under tall building box foundations (parameter of model was acquired from CFG pile composite subgrade of Beijing Jiachen plaza). Result of analysis detailed explain its characteristics from six-aspect.1. Bring diverse pressure to bear on motherboard of foundation.2. Distinct thickness of motherboard of foundation.3. Difference replacement rate of area of CFG-pile under the motherboard of foundation.4. Disparate thickness of cushion of CFG-pile composite subgrade.5. Different longth of CFG-pile.6. Distinct outward extension of CFG-pile in the core region.After analyze stress field and deformation field of CFG-pile composite subgrade , a good result were had application in composite subgrade of Beijing Jiachen plaza (twenty-six floor on ground and three floor under ground). At the stage of construction, a practice text was taked about nature foundation、 CFG-pile and composite subgrade bearing load and pile-soil ratio of stress. At the same time, a long period of observation were put in practice when gradually add load of construction. In the end, good conclusions with satisfied economic was been given through comparing of results of tests in site、 FEM simulation and calculation of更多还原