浅埋大断面黄土隧道灰土挤密桩复合地基受力与变形性状研究

发布时间：2018-05-07 09:44

本文选题：公路隧道 + 软弱黄土　；参考：《长安大学》2015年硕士论文

【摘要】：软弱黄土公路隧道的受力变形一直是学术界和工程界比较关注的问题。由于黄土特殊的工程性质,黄土公路隧道隧底的受力变形特征也与其它山岭隧道有着很大的不同。为了能充分认识黄土公路隧道隧底的受力与变形特征,以便提出有效的基底加固措施。本文以付家窑隧道为依托,运用有限元软件、结合现场实测等手段分析研究浅埋条件下隧道基底桩体及桩间土的受力与变形规律。主要工作如下:1、根据付家窑隧道现场测试结果,分析浅埋条件下扁平大断面三车道黄土隧道边墙压力、基底围岩压力和附加应力的大小随时间的变化规律,得到隧道基底围岩应力分布特征。2、运用MIDAS/GTS有限元软件,以依托工程为背景,对隧底未处理条件下隧道施工过程进行二维数值模拟。分析隧道基底围岩压力的分布规律、隧道开挖过程中竖向位移和水平向位移的变化趋势以及隧底围岩塑性区的分布特征。3、对采用灰土挤密桩处理后隧道的施工过程进行数值模拟,分析隧道基底桩身应力、桩身轴力及桩间土应力沿灰土挤密桩桩深的分布特征、隧道开挖过程中隧底围岩位移的变化规律及隧底围岩塑性区的分布特点。4、利用有限元软件,对浸水条件两种工况下的隧道施工过程进行二维数值模拟,研究极端条件下软弱黄土隧道基底桩身应力、桩身轴力及桩间土应力沿深度方向的分布规律、隧道支护完成后隧底围岩竖向和水平向位移的变化规律及隧底塑性区的分布特征。
[Abstract]:The deformation of soft loess highway tunnel is always concerned by academia and engineering circles. Because of the special engineering properties of loess, the deformation characteristics of loess highway tunnel bottom are different from those of other mountain tunnels. In order to fully understand the stress and deformation characteristics of loess highway tunnel bottom in order to put forward effective foundation reinforcement measures. Based on the Fujiayao tunnel, this paper analyzes and studies the stress and deformation law of the foundation pile and the soil between piles under the condition of shallow burial by means of finite element software and field measurement. The main work is as follows: 1. According to the field test results of Fujiayao tunnel, the variation law of the pressure on the side wall, the pressure of the surrounding rock and the additional stress in the surrounding rock of the loess tunnel with large flat section and three lanes under shallow burial with time are analyzed. The stress distribution characteristics of the surrounding rock of the foundation of the tunnel are obtained. Using MIDAS/GTS finite element software, the two-dimensional numerical simulation of the tunnel construction process under the untreated condition of the tunnel bottom is carried out with the backing of the engineering as the background. The distribution law of surrounding rock pressure in tunnel basement is analyzed. The variation trend of vertical displacement and horizontal displacement during tunnel excavation and the distribution characteristics of plastic zone of surrounding rock in tunnel bottom are analyzed by numerical simulation of the tunnel construction process after the treatment of lime-soil compaction pile, and the stress of foundation pile is analyzed. The distribution characteristics of axial force of pile body and soil stress between piles along the depth of lime-soil compacted pile, the variation law of surrounding rock displacement in tunnel excavation and the distribution characteristics of plastic zone in surrounding rock of tunnel bottom. The 2-D numerical simulation of tunnel construction process under two conditions is carried out to study the distribution of pile stress, axial force of pile body and soil stress between piles in the direction of depth under extreme conditions of weak loess tunnel. The variation law of vertical and horizontal displacement of surrounding rock and the distribution characteristics of plastic zone of tunnel bottom after the completion of tunnel support.
【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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