桩后土体加固对基坑支护体系内力变形影响的有限元分析

发布时间：2018-06-07 14:56

本文选题：桩后土体加固 + 内支撑支护形式　；参考：《天津大学》2014年硕士论文

【摘要】：目前在基坑支护设计中,为保证基坑工程的安全性,往往在支护桩后设置一定厚度的水泥土搅拌桩。但基坑支护设计软件不能够对支护桩后水泥土搅拌桩进行计算,因此本文采用PLAXIS有限元程序通过对支护桩后土体进行加固来考虑水泥土搅拌桩对基坑支护体系内力和变形的影响。本文通过一内支撑基坑工程实例,首先介绍了内支撑基坑支护形式的计算原理。其次采用当前两种基坑支护设计软件(两种软件为同济启明星基坑支护设计软件FRWS和理正基坑支护设计软件FSPW)进行基坑支护系统方案设计,对比两种基坑支护设计软件对于内支撑基坑支护形式计算的差异。最后采用PLAXIS2D有限元程序建立平面应变有限元模型,分别建立了桩后土体未加固和加固两种有限元模型。通过改变桩后土体加固有限元模型中土体加固的厚度,分析支护桩位移、地表沉降和支撑轴力的变化规律。分析得出支护桩后设置的水泥土搅拌桩能够承担部分土压力,减小支护结构的位移和地表沉降,增强基坑支护体系的安全性。对比分析基坑变形实测值与设计值,验证了水泥土搅拌桩的挡土作用。本文通过采用PLAXIS程序对桩后土体加固进行有限元分析,得出了支护桩后设置水泥土搅拌桩对基坑支护体系内力和变形的影响规律,对深基坑支护结构的设计和施工具有重要的参考价值。
[Abstract]:At present, in the design of foundation pit support, in order to ensure the safety of foundation pit engineering, cement soil mixing piles with a certain thickness are often set up behind the supporting piles. However, the software of foundation pit support design can not calculate the cement soil mixing pile behind the supporting pile. In this paper, the influence of cement soil mixing pile on the internal force and deformation of foundation pit support system is considered by using PLAXIS finite element program to reinforce the soil behind the supporting pile. This paper first introduces the calculation principle of the support form of the inner braced foundation pit through an example of the foundation pit with inner bracing. Secondly, two kinds of foundation pit support design software (Tongji Qi-xing foundation pit support software FRWS and Lizheng foundation pit support design software FSPW) are used to design the foundation pit support system. The difference between the two kinds of software in the calculation of the support forms of the inner braced foundation pit is compared. Finally, the plane strain finite element model is established by using PLAXIS2D program, and two kinds of finite element models of unreinforced and strengthened soil after pile are established respectively. By changing the thickness of soil reinforcement in the finite element model of soil reinforcement after pile, the variation law of displacement, surface settlement and supporting axial force of supporting pile is analyzed. It is concluded that the cement-soil mixing pile after supporting pile can bear some soil pressure, reduce the displacement of supporting structure and ground subsidence, and enhance the security of foundation pit support system. The soil retaining effect of cement soil mixing pile is verified by comparing the measured value and design value of foundation pit deformation. In this paper, the finite element analysis of soil reinforcement behind piles is carried out by using PLAXIS program, and the influence of cement soil mixing piles on the internal force and deformation of foundation pit supporting system is obtained. It has important reference value for the design and construction of deep foundation pit supporting structure.
【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】：TU753

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