高喷搅拌水泥土插芯组合桩复合地基工作性状研究

发布时间：2018-06-01 18:20

本文选题：复合地基 + 水泥土插芯组合桩　；参考：《山东建筑大学》2017年硕士论文

【摘要】：高喷搅拌水泥土插芯组合桩复合地基是由柔性桩(高喷搅拌水泥土桩)与同心植入的刚性桩(混凝土桩)组成的复合材料桩作为竖向增强体,并与桩周土共同承担上部荷载而形成的一种适用于软弱土地层条件的新型复合地基。可以充分发挥水泥土桩桩身侧阻力和芯桩桩身材料强度,融合了柔性桩复合地基和刚性桩复合地基各自的优势,具有设计可调性强、性价比高、经济环保等特点。在已有研究的基础上,通过现场载荷试验以及有限差分软件的数值计算分析,对竖向荷载下高喷搅拌水泥土插芯组合桩复合地基的承载及变形性状进行了研究。现场载荷试验表明,高喷搅拌水泥土插芯组合桩对减小复合地基沉降,提高其承载力具有显著影响,地基承载力提高幅度为天然地基的1.55~2.71倍;复合地基中组合桩桩身荷载传递规律呈明显的摩擦桩特性,芯桩底端端阻比约为10%;单桩复合地基承载力特征值对应荷载条件下,增强体承载力发挥系数约为0.59,桩侧土承载力发挥系数约为1.38;复合地基荷载分担比、应力比随上部荷载的变化而动态调整,其变化规律与荷载水平、面积置换率、芯桩长度比等因素有关。利用有限差分软件FLAC3D计算分析了不同组合桩尺寸、复合地基面积置换率、地层条件等因素对高喷搅拌水泥土插芯组合桩复合地基的承载及变形性状的影响,给出了对此种复合地基组合桩芯桩与水泥土桩的长度比、桩径比以及桩间距的建议取值范围;讨论了地层条件的改变对荷载分担比、桩身轴力传递规律等的影响,并指出应尽量将组合桩的芯桩末端或水泥土桩末端设在性质较好的地层。文章的研究内容为高喷搅拌水泥土插芯组合桩复合地基的工程应用提供了一些理论上的指导,并对下一步的研究内容给出了建议,为此种复合地基的推广应用提供了一些理论参考。
[Abstract]:The composite foundation is composed of flexible pile (high jet mixing cement soil pile) and concentric rigid pile (concrete pile) as vertical reinforcement. A new composite foundation, which is suitable for the soft soil layer condition, is formed by bearing the upper load together with the soil around the pile. It can give full play to the side resistance of cement soil pile and the strength of core pile material. It combines the advantages of flexible pile composite foundation and rigid pile composite foundation, and has the characteristics of strong design adjustability, high performance-price ratio, economic and environmental protection, etc. On the basis of existing research, the bearing capacity and deformation behavior of composite foundation with high jetting mixing cement-soil intercalated pile under vertical load is studied by field load test and numerical calculation and analysis of finite difference software. The field load test shows that the composite pile with high jetting mixing cement and soil core has a significant effect on reducing the settlement of the composite foundation and increasing its bearing capacity, and the increase of the bearing capacity of the foundation is 1.55 ~ 2.71 times of that of the natural foundation. The law of load transfer of composite pile in composite foundation is obvious characteristic of friction pile, the ratio of end to end resistance of core pile is about 10, the bearing capacity characteristic value of single pile composite foundation corresponds to load condition, The coefficient of bearing capacity of reinforcing body is about 0.59, the coefficient of bearing capacity of pile-side soil is about 1.38.The ratio of load-sharing and stress of composite foundation is adjusted dynamically with the change of upper load, its changing law and load level, area replacement ratio, The length ratio of core pile is related to other factors. By using finite difference software FLAC3D, the effects of different composite pile sizes, replacement rate of composite foundation area, and formation conditions on the bearing capacity and deformation behavior of composite foundation with high jet mixing cement-soil composite pile are analyzed. The suggested range of length ratio, pile diameter ratio and pile spacing of composite pile core pile and cement soil pile on composite foundation is given, and the influence of the change of formation conditions on load sharing ratio and axial force transfer law of pile body is discussed. It is pointed out that the core pile end or the cement soil pile end of composite pile should be located in the stratum with better properties as far as possible. The research content of this paper provides some theoretical guidance for the engineering application of the composite foundation with high jetting mixing cement soil inserted core pile, and gives some suggestions for the next research content. Therefore, some theoretical references are provided for the popularization and application of this kind of composite foundation.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU473.1

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