水泥搅拌桩复合土钉支护技术的应用与研究

发布时间：2018-09-13 13:29

【摘要】：近几年由于经济的快速增长,房地产业也得到快速发展,高层建筑如雨后春笋般涌现,地上空间变得越来越紧缺,利用地下空间已经是一种趋势,然而利用地下空间就得面临一个问题—基坑支护。土钉支护因其具有简单、快速、经济等优点被大量采用。但是土钉支护也有一些缺点,不宜在软土地区使用,当周围环境比较复杂时且对变形要求控制较严时也不宜使用,因而在很大程度上限制了该项支护技术的应用,复合土钉支护在此背景下产生。复合土钉支护是基于纯土钉支护发展起来的,它利用了其他支护的优点来弥补单纯土钉支护的不足,同时又保留了土钉支护的很多优点。但是复合土钉支护起步较晚,对其作用机理不明确,理论依据不够充分,更多的是依靠经验。为了更加深入地了解复合土钉支护,使得这项技术得到更为广泛的应用。论文以水泥搅拌桩复合土钉支护为对象,运用abaqus有限元软件对其模拟分析,目的在于探讨复合土钉的作用机理,总结复合土钉支护的变形与内力规律;论文同时对土钉参数进行了优化设计,也对搅拌桩的最佳厚度以及搅拌桩插入坑底的最佳深度给出合理的建议。本文的主要工作及创新点如下:(1)阐述了土钉支护的优点的同时指出了土钉支护的缺点,进而引出复合土钉支护。由于复合土钉支护目前理论研究相对落后,作用机理不是很明确,指出论文将以搅拌桩复合土钉支护为对象,对复合土钉支护进行更为深入的研究。(2)列举了几个搅拌桩复合土钉支护技术在具体工程中运用,指出搅拌桩复合土钉支护在哪些条件下应用优势明显。(3)探讨了搅拌桩复合土钉支护稳定性验算的几方面内容。(4)基于abaqus有限元软件,假想一理想模型,对其进行数值模拟,得出搅拌桩的水平位移、地表沉降、坑底隆起、以及土钉与搅拌桩的内力变化规律。并对土钉的参数进行优化,最后探讨了搅拌桩的最佳厚度与最佳插入坑底的深度。(5)结合一具体工程实例,再次用有限元软件对其模拟,并结合实际监测数据、以及理正软件计算结果,将三者结果进行对比分析,指出搅拌桩复合土钉结构部分变形及内力的规律在一定程度上是合理的,并就实例中支护结构的各参数选取给予评价,为设计提供一些参考信息。
[Abstract]:Due to the rapid economic growth in recent years, the real estate industry has also been rapid development, high-rise buildings have sprung up, the aboveground space has become increasingly scarce, the use of underground space has been a trend. However, the use of underground space will have to face a problem-foundation pit support. Soil nailing is widely used because of its simplicity, rapidity and economy. However, soil nailing support also has some shortcomings, it is not suitable for use in soft soil areas, and when the surrounding environment is more complicated and the deformation requirements are more strict, so the application of this support technology is limited to a large extent. Composite soil nailing is produced under this background. Composite soil nailing support is based on the development of pure soil nailing support, it uses the advantages of other support to make up for the shortcomings of simple soil nailing support, while retaining many advantages of soil nailing support. But the composite soil nailing support started late, its action mechanism is not clear, the theoretical basis is not enough, more rely on experience. In order to understand the composite soil nailing, this technique is widely used. This paper takes the composite soil nailing support of cement mixing pile as an object, and uses abaqus finite element software to simulate and analyze it. The purpose of this paper is to discuss the action mechanism of composite soil nailing and to summarize the law of deformation and internal force of composite soil nailing support. At the same time, the optimum design of soil nailing parameters and the optimum thickness of mixing pile and the optimum depth of mixing pile into the bottom of the pit are given. The main work and innovations of this paper are as follows: (1) the advantages of soil nailing support are expounded and the shortcomings of soil nailing support are pointed out. Because the theoretical research of composite soil nailing is relatively backward and the mechanism of action is not very clear, it is pointed out that the paper will take the composite soil nailing support of mixing pile as the object. Further research on composite soil nailing support is carried out. (2) several composite soil nailing technologies of mixing piles are listed and applied in concrete projects. It is pointed out that the advantages of composite soil nailing support of mixing pile are obvious under which conditions. (3) several aspects of checking calculation of stability of composite soil nailing support of mixing pile are discussed. (4) based on abaqus finite element software, an ideal model is hypothesized and simulated numerically. The horizontal displacement, ground subsidence, bottom uplift and internal force variation of soil nailing and mixing pile are obtained. The parameters of soil nailing are optimized, and the optimum thickness and depth of mixing pile are discussed. (5) combined with a concrete engineering example, the finite element software is used to simulate the soil nailing again, and the monitoring data are combined with the actual monitoring data. By comparing and analyzing the three results, it is pointed out that the law of partial deformation and internal force of mixed pile composite soil nailing structure is reasonable to a certain extent, and the selection of various parameters of supporting structure in the example is evaluated. Provides some reference information for design.
【学位授予单位】：安徽工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU753

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