深埋大断面黄土隧道旋喷桩复合地基受力与变形性状研究

发布时间：2018-03-08 01:04

本文选题：黄土隧道　切入点：基底处理　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：黄土隧道开挖以后,天然基底的承载力往往难以满足隧道结构的受力要求,在隧道修建完成以后,基底会产生较大的变形,因此,为了隧道施工过程及后期运营的安全,必须对地基进行加固处理。本文以付家窑1#隧道为依托,该隧道采用旋喷桩对基底进行了加固处理。为了分析隧道基底桩体及桩间土等受力与变形的规律,利用现场测试和有限元等手段进行了分析研究,主要分析了深埋条件下未处理隧底与旋喷桩处理后基底受力与变形的特征。结合分析结果,最后对旋喷桩加固后隧道的稳定性进行了评价。论文主要研究内容如下:1.根据付家窑隧道现场测试结果,分析深埋条件下扁平大断面三车道黄土隧道桩顶和桩间土的受力情况、边墙与基底围岩压力的大小随时间的变化规律以及隧道基底沉降变形的基本变化趋势;2.利用MIDAS/GTS有限元软件,以依托工程为背景,对隧底未处理与利用旋喷桩处理的隧道施工过程分别进行二维数值模拟。分析隧道基底桩身应力、桩身轴力及桩间土应力沿旋喷桩埋深的分布规律、隧道开挖过程中竖向位移与横向位移的变化趋势以及隧道基底塑性区的分布情况;3.根据现场测试及数值模拟结果,分析隧道施工完成后,现场测试基底变形累计值、数值模拟隧道施工过程的基底变形、拱顶下沉及周边收敛的累计最大值、衬砌的安全系数及塑性区范围,并通过数值模拟分析隧道施工完成后在仰拱回填及支护结构自重作用下引起的沉降变形,将实测和模拟结果与规范允许值进行比较,评价旋喷桩对黄土隧道基底加固后隧道的稳定性。通过对旋喷桩处理黄土隧道基底的研究,旨在为类似隧道工程设计和安全施工提供参考和借鉴。
[Abstract]:After the loess tunnel is excavated, the bearing capacity of the natural foundation is often difficult to meet the stress requirements of the tunnel structure. After the completion of the tunnel construction, the foundation will produce large deformation, therefore, in order to ensure the safety of the tunnel construction process and later operation, The foundation must be strengthened. In this paper, based on Fujiayao 1# tunnel, the foundation is strengthened with rotary jet pile. In order to analyze the law of stress and deformation of the foundation pile and the soil between piles, etc. By means of field test and finite element method, the characteristics of the stress and deformation of the foundation after the treatment of the untreated tunnel bottom and the rotary jet pile under the condition of deep burying are mainly analyzed, and the results are combined with the results of the analysis. Finally, the stability of the tunnel strengthened by rotary jet grouting pile is evaluated. The main contents of this paper are as follows: 1.According to the field test results of Fujiayao tunnel, the stress on the pile top and the soil between piles of three lanes loess tunnel with flat and large section under the condition of deep burying is analyzed. The variation law of side wall and surrounding rock pressure with time and the basic change trend of tunnel foundation settlement and deformation 2.Using MIDAS/GTS finite element software, taking the backing engineering as the background, Two dimensional numerical simulation is carried out on the untreated tunnel bottom and the tunnel construction process treated by rotary jet pile respectively. The distribution law of the stress of the foundation pile, the axial force of the pile body and the soil stress between the piles along the burying depth of the pile is analyzed. The variation trend of vertical displacement and transverse displacement during tunnel excavation and the distribution of plastic zone of tunnel base are analyzed. According to the results of field test and numerical simulation, the cumulative value of deformation of base after tunnel construction is analyzed. Numerical simulation of the foundation deformation during tunnel construction, the cumulative maximum value of vault subsidence and peripheral convergence, the safety factor of lining and the range of plastic zone, The settlement deformation caused by the backfill of invert arch and the self-weight of supporting structure is analyzed by numerical simulation, and the measured and simulated results are compared with the allowable values of the code. In order to provide reference for similar tunnel engineering design and safety construction, the stability of loess tunnel foundation strengthened by rotary jet grouting pile is evaluated, and the research on treatment of loess tunnel base by rotary jet pile is carried out.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U452.11

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