深埋长大公路隧道主要工程地质问题分析及对策研究

发布时间：2018-07-28 10:22

【摘要】：深埋长大隧道埋深大、距离长,施工周期长、成本高,多经过地形复杂区域、施工困难,不可避免地会碰到一系列如塌方、岩爆、围岩大变形等工程地质灾害问题。因此,对这些深埋隧道工程施工中常见的主要地质灾害问题及对应措施进行分析研究具有重要意义。以荣乌高速公路营尔岭隧道为实际工程背景,通过地质资料及现场勘察,对隧址区工程地质情况做了初步分析。结合工程实例,采用Midas GTS NX有限元分析软件对深埋隧道软弱围岩管棚处理效果做了深入研究,对预开挖段隧道围岩做了岩爆和大变形的预测研究。主要内容如下:(1)模拟了不同厚度的注浆加固区,隧道围岩的应力场、变形场及塑性区分布特征情况,定量分析了管棚注浆加固法对隧道围岩的加固效果。得出注浆加固区并不是厚度越大越好,综合施工安全和经济合理等方面因素,厚度取5m是较为合理的。(2)对深埋隧道软弱围岩管棚加固段的施工过程进行数值模拟。通过模拟,重点分析了开挖后隧道围岩的受力及变形特征,并对不同预支护条件下隧道开挖掌子面的稳定性进行了评价。分析得出管棚的注浆加固效果在对隧道附近围岩应力重分布和控制围岩的收敛变形方面起到了决定性作用,而管棚的梁效应则能有效控制开挖掌子面的拱顶沉降和纵向鼓出,对开挖面的稳定性起到了关键作用。(3)对不同埋深下的围岩进行数值模拟,预测发生岩爆或者大变形的可能性。通过研究隧道附近围岩的应力特征并结合岩爆的判定依据,得出营尔岭隧道有发生岩爆的可能性,轻微岩爆区约占隧道总长的38%,中等岩爆区约占7%,埋深在200m以上的坚硬完整围岩会发生轻微岩爆甚至中等岩爆,主要危险区位于拱脚及边墙部位;通过研究隧道的变形特征并结合围岩大变形的判定依据,得出营尔岭隧道埋深在600m以上的软弱破碎围岩会发生大变形,程度为轻度。
[Abstract]:The deep buried long tunnel is very deep, long distance, long construction period, high cost, passing through the complicated terrain area, and the construction is difficult, so it will inevitably encounter a series of engineering geological disasters such as collapse, rockburst, large deformation of surrounding rock and so on. Therefore, it is of great significance to analyze and study the main geological hazards and corresponding measures in the construction of these deep buried tunnels. Taking Yingerling Tunnel of Rongwu Expressway as the actual engineering background, through geological data and on-the-spot investigation, this paper makes a preliminary analysis of the engineering geological situation in the tunnel site area. Combined with engineering examples, the treatment effect of soft surrounding rock pipe shed in deep buried tunnel is deeply studied by using Midas GTS NX finite element analysis software, and the prediction of rockburst and large deformation of tunnel surrounding rock in pre-excavated section is studied. The main contents are as follows: (1) the stress field, deformation field and plastic zone distribution characteristics of different thickness grouting reinforcement zone, tunnel surrounding rock are simulated, and the effect of pipe shed grouting reinforcement method on tunnel surrounding rock is quantitatively analyzed. It is concluded that the grouting reinforcement area is not the thicker the better, the safety and economy are reasonable, and the thickness of 5 m is reasonable. (2) numerical simulation of the construction process of the soft surrounding rock pipe shed reinforcement section of deep buried tunnel is carried out. Through simulation, the stress and deformation characteristics of tunnel surrounding rock after excavation are analyzed, and the stability of tunnel excavation face under different pre-supporting conditions is evaluated. It is concluded that the grouting reinforcement effect of pipe shed plays a decisive role in stress redistribution and control of convergence and deformation of surrounding rock near tunnel, while beam effect of pipe shed can effectively control the settlement of arch roof and longitudinal bulging of excavation face. It plays a key role in the stability of excavated surface. (3) numerical simulation of surrounding rock with different buried depth is carried out to predict the possibility of rock burst or large deformation. By studying the stress characteristics of surrounding rock around the tunnel and combining with the judging basis of rock burst, the possibility of rock burst in Yingerling tunnel is obtained. The minor rockburst area accounts for about 38 of the total length of the tunnel, and the moderate rockburst area accounts for about 7. The rock burst or moderate rockburst will occur in the hard and intact surrounding rock with a depth of more than 200 m. The main danger area is located at the arch foot and the side wall. By studying the deformation characteristics of the tunnel and judging the large deformation of surrounding rock, it is concluded that the weak and broken surrounding rock with buried depth above 600m in Yingerling tunnel will undergo large deformation, and the degree is mild.
【学位授予单位】：烟台大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U452.11

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