桩间土流失对双排桩支护结构变形的影响分析

发布时间：2019-02-12 07:14

【摘要】：随着城市化进程的加快,地下结构大量涌现,双排桩支护结构作为一种悬臂式空间支护体系,以其施工快捷、抗侧移刚度大等优点,成为一种应用广泛的支护形式。然而双排桩支护结构的受力与变形较为复杂,目前对于该支护体系的理论分析还不完善,尤其是桩间土对双排桩的作用还有待进一步的研究。本文在分析双排桩计算理论的基础上,运用有限元软件ABAQUS建立双排桩有限元模型,研究了桩间土流失与坑底土体变软对双排桩支护体系变形与受力的影响,并以工程实例为背景进行了进一步的验证。本文的主要内容如下:(1)分析了双排桩支护结构的计算理论。详细阐述了五种具有代表性的计算方法的原理、特点及适用性;介绍了基于ABAQUS软件的有限元法,对本构模型的选取、桩土接触问题的处理及基坑开挖工况的模拟等问题进行了分析。(2)建立考虑止水帷幕的三维有限元模型,分析了桩距、排距两个方向上桩间土流失对双排桩支护体系变形与受力的影响,可知桩距方向桩间土流失对排桩桩身侧移和弯矩以及水泥土搅拌桩桩身侧移的影响均很小,而排距方向桩间土流失对三者的侧移和受力都有较大影响。同时,研究了排距方向桩间土流失率对双排桩支护体系的影响。此外,建立二维有限元模型,研究了坑底土体变软对双排桩支护体系变形与受力的影响。(3)以天津某基坑工程为例,分析了实际工程中桩间土流失与坑底土体变软对双排桩变形产生的影响,验证了本文所采用的有限元模型的适用性以及分析结果的合理性。
[Abstract]:With the acceleration of urbanization, underground structures have emerged in large numbers. As a cantilever space support system, double-row pile supporting structure has become a widely used support form because of its advantages of quick construction and large anti-lateral stiffness. However, the stress and deformation of the double-row pile supporting structure are more complex, so the theoretical analysis of the supporting system is not perfect, especially the effect of soil between piles on the double-row pile is still to be further studied. Based on the analysis of the calculation theory of double-row piles, the finite element model of double-row piles is established by using the finite element software ABAQUS, and the influence of soil loss between piles and soft soil on the deformation and force of double-row pile supporting system is studied. Further verification is carried out on the background of engineering examples. The main contents of this paper are as follows: (1) the calculation theory of double row pile supporting structure is analyzed. The principle, characteristics and applicability of five representative calculation methods are described in detail. The finite element method based on ABAQUS software is introduced. The selection of constitutive model, the treatment of pile-soil contact problem and the simulation of excavation conditions are analyzed. (2) the three-dimensional finite element model considering the waterproof curtain is established, and the pile spacing is analyzed. The influence of soil loss between piles on the deformation and force of double row pile support system in two directions shows that the soil loss between piles in the direction of pile spacing has little effect on lateral displacement and bending moment of pile body and lateral displacement of cement soil mixing pile. The soil loss between piles in the row direction has great influence on the lateral displacement and force. At the same time, the influence of soil loss rate between piles in the direction of row distance on the support system of double row piles is studied. In addition, a two-dimensional finite element model is established to study the effect of soft soil on the deformation and force of double-row pile supporting system. (3) A foundation pit project in Tianjin is taken as an example. The effects of soil loss between piles and soft soil on the deformation of double-row piles in practical engineering are analyzed. The applicability of the finite element model and the rationality of the analysis results are verified.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU473.1

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