浅埋偏压连拱隧道数值模拟及其优化分析

发布时间：2018-02-26 05:25

本文关键词： 浅埋偏压连拱隧道施工变形数值模拟监控量测　出处：《西安建筑科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,随着我国经济的快速发展,我国高速公路隧道工程技术水平得到了迅速推进,由于连拱隧道能够更好地适应山区特殊地形,线形流畅,近年来连拱隧道越来越多的被实际工程所应用。论文以湖北天鹅连拱隧道为背景,采用有限元软件MIDAS/GTS对偏压连拱隧道的施工过程进行数值模拟,通过对围岩和支护结构应力应变规律的研究,对不同开挖方案和开挖顺序优化分析,结合现场监控量测资料,应用灰色建模理论对监测数据进行分析预测。论文的主要研究成果为:(1)采用三导洞法施工时,隧道施工完成后应力最大值在出口处中隔墙的左侧腰部和脚部为9.0MPa;采用中导洞法施工时,左洞上台阶开挖后,左洞仰拱部分松动区和先前开挖中导洞时形成的松动区相互重叠形成一体,隧道施工完成后应力最大值在中隔墙为10.3MPa。采用三导洞施工左右洞最终沉降为12.25mm,10.09mm,而采用中导洞施工,左右洞的最终沉降值为13.14mm,10.95mm。三导洞法开挖中隔墙拱顶、腰部和底部应力值分别为4.6MPa、2.6MPa和3.0MPa,小于中导洞法的5.0MPa、3.0MPa和4.0MPa,说明先行开挖两侧导洞能够释放部分围岩压力,有效减小中隔墙的受力。(2)就中隔墙而言,左洞先行开挖(工况一)中隔墙最大压应力为11.0MPa小于右洞先行开挖(工况二)的最大压应力值12.0MPa,对于中隔墙最大拉应力值,工况一为1.2MPa小于工况二最大值2.8MPa;从初衬受力情况来看,工况一和工况二的最大位移值分别为19.23mm、24.97mm,初衬最大拉应力分别为1.1MPa、2.1MPa,最大压应力分别为8.4MPa、10.0MPa。从围岩塑性区来看,工况一的塑性区主要分布在两侧拱腰处和中隔墙顶端,工况二的围岩塑性区位于中隔墙顶部偏压侧及两侧拱腰处。(3)ZK72+755断面拱顶沉降、水平收敛、仰拱沉降的预测值分别为20.78mm、7.49mm、10.50mm;经过现场监控量测,ZK72+755断面的实测值分别为21.00mm、7.68mm、9.45mm。由此可见,方程预测接近实测值,可见,灰色GM(1,1)模型可以准确的模拟围岩的时间位移序列,预测精度达到了隧道安全施工的要求。(4)天鹅连拱隧道的拱顶沉降、水平收敛和仰拱沉降趋于稳定时的位移分别为:15.0mm、5.0mm和8.0mm,稳定所需时间为35天左右。拱顶沉降和仰拱沉降值较大。初衬与围岩接触压力随着掌子面的推进基本呈逐渐增长态势,监测点在开挖35天左右,压力值趋于稳定,左拱肩承受的压力基本都大于右拱肩。
[Abstract]:In recent years, with the rapid development of China's economy, China's highway tunnel engineering technology has been advancing rapidly, because the arch tunnel can better adapt to the special terrain and terrain, streamline, arch tunnel in recent years has been more and more practical engineering applications. This paper takes Hubei Swan arch tunnel as the background of numerical simulation of the construction process using finite element software MIDAS/GTS to bias arch tunnel, through the research on the stress and strain of the surrounding rock and supporting structure, to different excavation schemes and optimization of excavation sequence analysis, combined with field monitoring data, the grey modeling theory is applied to analyze and forecast the monitoring data of the main research results of this paper. As follows: (1) the three heading construction, tunnel construction after the completion of the maximum stress in the wall at the outlet of the left side of the waist and feet is 9.0MPa; the heading construction, left Bench tunnel after excavation, part of loose zone of left tunnel invert and loose zone formed previously in the excavation of pilot tunnels overlapping integrated tunnel construction after the completion of the maximum stress in the walls for the 10.3MPa. using the three heading construction hole about final settlement of 12.25mm, 10.09mm, and used the heading construction, final settlement. The hole is 13.14mm, 10.95mm. three heading excavation method of partition in the vault, waist and bottom stress values were 4.6MPa, 2.6MPa and 3.0MPa, less than the central drift method of 5.0MPa, 3.0MPa and 4.0MPa, indicating the excavation in advance on both sides of the guide hole can release the pressure of surrounding rock, effectively reduce the wall stress (2) on the wall. First, the left tunnel excavation (condition) the maximum compressive stress is less than 11.0MPa in the wall of right tunnel excavation in advance (case two) the maximum stress value of 12.0MPa, the partition of the maximum value of tensile stress, a condition for less than 1.2MPa conditions The maximum value of two 2.8MPa; from the lining stress situation, the maximum displacement and the status of the two values were 19.23mm, 24.97mm, lining the maximum tensile stress were 1.1MPa, 2.1MPa, the maximum compressive stress of 8.4MPa, 10.0MPa. from the surrounding rock plastic zone, plastic zone of the main conditions of a distribution on both sides of the arch waist and in the top of the partition, the plastic zone of the surrounding rock condition two is located in the side wall top bias on both sides and the arch waist. (3) ZK72+755 section vault settlement, horizontal convergence, forecast the settlement value of inverted arch were 20.78mm, 7.49mm, 10.50mm; through field monitoring, measurement of ZK72+755 section the values were 21.00mm, 7.68mm, 9.45mm. shows that the equation predicts close to the measured values, the grey GM (1,1) model can accurate simulation of surrounding rock displacement time series, the forecast accuracy of the tunnel construction safety requirements. (4) the settlement of the Swan arch tunnel vault, Horizontal convergence and invert displacement stable were: 15.0mm, 5.0mm and 8.0mm, time required for 35 days. The vault settlement and the settlement value is larger. The inverted arch lining and surrounding rock stress with the working face of the advancing basic showed a gradual growth, monitoring points in the excavation of 35 days or so, pressure the value tends to be stable, the left spandrel pressure are greater than the right shoulder.

【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.4

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