【作者】 张振；

【导师】 窦远明；

【作者基本信息】 河北工业大学 ， 结构工程， 2002， 硕士

【摘要】 水泥土组合桩在国内是一项刚刚开展研究的地基加固新技术。水泥土组合桩是在水泥土搅拌桩成桩之后，水泥土初凝之前，用压桩机械将预制混凝土芯桩压入水泥土体内，待水泥土凝固后，芯桩与水泥土共同工作，承受上部荷载的一种新桩型。水泥土组合桩有机的结合了混凝土预制桩与水泥土搅拌桩的优点，形成了一种中间强度高、四周强度低的合理桩身结构，充分发挥了芯桩与水泥土桩体的性能。 本文对水泥土组合桩进行了试验研究和理论分析，采用有限元法对单桩的荷载传递性状进行分析，编制了单桩非线性分析的有限元程序。对工程试桩的静载试验结果进行分析，确定单桩极限承载力。室外模型桩试验通过在桩身埋设测试元件，研究水泥土组合桩荷载传递规律以及变形特性。 利用有限元计算分析了同比(桩长相同、桩径相同)水泥土组合桩、水泥土搅拌桩和混凝土钻孔灌注桩，得到了它们的荷载沉降曲线、桩身应力曲线、桩身轴力曲线、桩侧桩端分担荷载曲线等，通过这些曲线对它们的荷载传递规律以及变形特性进行了深入的分析。 利用有限元对相同的外包搅拌桩形式、相同芯桩截面、不同芯桩桩长的水泥土组合桩的Q-S曲线进行了对比，得出了最优的芯桩桩长与水泥土组合桩桩长比。 根据室内外试验和有限元分析的结果，提出水泥土组合桩的构造要求和水泥土组合桩竖向承载力计算公式。和目前常用桩在施工工艺、施工速度、成桩质量及经济性等进行了比较，得出此种桩在多层建筑中广泛应用前景的结论。更多还原

【Abstract】 The cement-soil mixing pile with concrete core is a new soil improvement method, it means that, a concrete core is plugged into cement-soil mixing pile. Concrete core pile and the cement-soil mixing pile undertake together vertical load. It appropriately combines the advantages of the precast concrete pile with the cement-soil mixing pile. The cement-soil mixing pile with concrete core forms a new reasonable structure of pile, it means that, the strength of core pile is more strong than the strength of round pile, therefore, the cement-soil mixing pile with concrete core takes advantage of property of concrete core pile and cement-soil mixing pile.This paper studies the cement-soil mixing pile with concrete core by experiment and by theory, analyzes the feature of load transferring using finite element method. Finite element program of non-linear analysis to pile is made and together with results of building test pile and model test pile, therefore, the feature of load transferring and deformation mechanism were deeply analyzed.The same type of cement-soil mixing pile with concrete core, concrete pile and cement-soil pile that means they have the same pile length and pile diameter is deeply analyzed by finite element program. We get the Q-S curve, the axis force of pile body curve, the stress of pile curve and the side and the end sharing load ratio of the pile curve by finite element program.With the help of the finite element program, the paper finds the relations between the pile’s parameter and its bearing capacity and load transferring properties.According to the results of the tests and finite element program, the paper put forward the structure need of the cement-soil mixing pile with concrete core, gives the calculating formula of pile’s bearing capacity. Finally, we draw a conclusion that the cement-soil mixing pile with concrete core will be used widely in Tianjin city zone by comparing with other piles in technology, speed, quality, and economy.更多还原