黄土地区CFG桩复合地基的极限承载性状研究

发布时间：2018-07-25 18:37

【摘要】：CFG桩复合地基是一种高效、性能优异的地基处理方式,已被广泛的应用于西安黄土地区高层、超高层建筑当中,但是当前对于高应力水平下CFG桩复合地基的极限承载性状研究的较少,因此本文主要理论推导出CFG桩复合地基的极限承载性状,并结合工程实例和数值模拟加以验证,以期能为工程实际所采用,达到科学合理的目的。(1)分析了 CFG桩复合地基的加固机理、桩土共同作用机理、桩土应力比和常用的承载力计算公式,为后续的理论推导打下坚实的基础。(2)将三次曲线方程用于中性点位置的推导,得到了更加准确、更加符合实际的中性点位置计算公式。基于CFG桩复合地基的基本理论和推导出的中性点位置,根据CFG桩复合地基中性面上下部分的不同特征,分别采用太沙基和迈耶霍夫破坏模型,理论推导出CFG桩复合地基的极限承载力。(3)以西安黄土地区某工程为背景,通过现场试验测出CFG桩复合地基的极限承载力,验证了理论推导的正确性。根据实测数据,分析了西安黄土地区高应力水平下,CFG桩复合地基的极限承载性状,以期指导实际工程的施工与设计。(4)利用FLAC 3D有限差分软件验证了理论推导的正确性和适用性。(5)整理了本文的研究成果,并结合实际探讨CFG桩复合地基在未来的发展前景以及目前所面对的技术难题。
[Abstract]:CFG pile composite foundation is an efficient and excellent foundation treatment method, which has been widely used in high-rise and super-high-rise buildings in Xi'an loess area. However, there is little research on the ultimate bearing behavior of CFG pile composite foundation under high stress level. Therefore, the ultimate bearing behavior of CFG pile composite foundation is deduced in this paper, which is verified by engineering examples and numerical simulation. In order to be used in engineering practice, scientific and reasonable purpose can be achieved. (1) the reinforcement mechanism, pile-soil interaction mechanism, pile-soil stress ratio and commonly used calculation formula of bearing capacity of CFG pile composite foundation are analyzed. It lays a solid foundation for the subsequent theoretical derivation. (2) the cubic curve equation is applied to the derivation of the position of the neutral point, and a more accurate and practical formula for calculating the position of the neutral point is obtained. Based on the basic theory of the CFG pile composite foundation and the deduced neutral point position, according to the different characteristics of the upper and lower neutral surface of the CFG pile composite foundation, the Terzaghi and Mayerhoff failure models are adopted, respectively. The ultimate bearing capacity of CFG pile composite foundation is derived theoretically. (3) taking a project in Xi'an loess area as the background, the ultimate bearing capacity of CFG pile composite foundation is measured by field test, which verifies the correctness of the theoretical derivation. Based on the measured data, the ultimate bearing behavior of CFG pile composite foundation at high stress level in Xi'an loess area is analyzed. In order to guide the construction and design of practical engineering. (4) the correctness and applicability of theoretical derivation are verified by using FLAC 3D finite difference software. (5) the research results of this paper are summarized. The prospect of CFG pile composite foundation in the future and the technical problems are discussed.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU473.1

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