兰新高铁碎屑流及薄层板岩隧道施工变形控制技术

发布时间：2018-01-08 22:07

本文关键词：兰新高铁碎屑流及薄层板岩隧道施工变形控制技术　出处：《北京交通大学》2015年博士论文　论文类型：学位论文

【摘要】：在青藏高原修建高铁长大隧道是一个世界性的技术难题,设计施工中会遇到一系列的风险和困难,高铁隧道修建标准更高,应对复杂地质困难的方法更难以把握。兰新高铁是目前世界上海拔最高的高速铁路,大梁隧道、祁连山隧道是兰新铁路海拔最高点,3800米,也是目前世界上海拔最高的高铁隧道,其修建过程中遇到了许多意想不到的困难,需要开展科技创新去解决。本文依托上述两座Ⅰ级风险隧道建设,对部分技术难题开展研究,主要内容为：隧道穿越碎屑流地层施工技术、高地应力薄层板岩隧道施工大变形控制技术、高原长大隧道机械降效量化指标研究。主要研究内容和成果如下：(1)通过理论分析及现场试验,揭示了碎屑流的工程特性,其主要组成为断层角砾、碎屑颗粒、砂土和水的混合物质,具有重度大、黏度高、流动性强、突发性强的特性,且分布范围广,隧道施工中难以预判。通过对隧道施工中碎屑流形成机理的研究,提出了碎屑流形成的三个阶段,即：先兆阶段、影响阶段、发生阶段。(2)结合祁连山隧道碎屑流段的工程施工,采用现场试验及理论分析方法,研究了隧道支护技术及开挖方法,提出了以碎屑体超前预报、掌子面封堵、超前高位泄水、超前强支护、强初期支护为核心的碎屑流地层高铁大断面隧道施工技术。(3)结合大梁隧道高地应力薄层板岩大变形控制难题,通过地应力的现场测试及围岩特性的试验分析,得出水平地应力(7.18～25.14MPa)大于垂直地应力,围岩强度与应力比在0.025～0.126范围,揭示了大梁隧道薄层板岩段变形为挤压型大变形,提出了高地应力薄层板岩隧道大变形分为严重大变形、中等大变形、轻微大变形和无大变形四级。(4)通过对系统锚杆的现场试验及数值模拟分析,得出了薄层板岩(Vc-2)系统锚杆效果不明显。通过对单层格栅、单层H175型钢、格栅+I20型钢双层支护的对比试验,得出双层支护控制变形效果最好,其次是单层H175型钢,单层格栅最差。(5)在严重大变形段,选取逐渐增强支护参数及预留变形量的四个试验段,分别进行现场试验,提出合理的预留变形量为50cm,并经过大量隧道变形数据统计分析,验证了该预留变形量具有95%以上的概率不侵限。(6)以高原环境实验舱配合发动机进气氮气掺混的方法,完成柴油机工作性能高原隧道环境模拟测试平台的设计和搭建,获得高原隧道施工环境下动力机械降效的量化评价。对高原长大隧道施工的设备配套及机械定额完善提供了支持。
[Abstract]:It is a worldwide technical problem to build the long tunnel of high-speed railway in Qinghai-Tibet Plateau. There will be a series of risks and difficulties in the design and construction of the tunnel, and the construction standard of the tunnel is higher. It is even more difficult to grasp the methods to deal with the complex geological difficulties. Lanxin high-speed railway is the highest elevation high-speed railway in the world at present, the Daliang Tunnel and Qilian Mountain Tunnel are the highest elevation of the Lanxin Railway 3800 meters above sea level. It is also the highest-elevation high-speed railway tunnel in the world at present, its construction process has encountered many unexpected difficulties, need to carry out scientific and technological innovation to solve. This paper relies on the above two class I risk tunnel construction. The main contents of this paper are as follows: the construction technology of tunnel through clastic flow and the control technology of large deformation in the construction of thin layer slate tunnel with high ground stress. The main contents and results of this study are as follows: 1) through theoretical analysis and field tests, the engineering characteristics of debris flow are revealed, the main composition of which is fault breccia. Clastic particles, sand and water mixture, with heavy, high viscosity, strong fluidity, sudden strong characteristics, and a wide range of distribution. It is difficult to predict the formation of debris flow in tunnel construction. Through the study of formation mechanism of debris flow in tunnel construction, three stages of formation of debris flow are put forward, namely: precursor stage and influence stage. In combination with the engineering construction of the debris flow section of Qilian Mountain Tunnel, the supporting technology and excavation method of the tunnel are studied by field test and theoretical analysis method, and the advanced prediction of the debris body is put forward. Face sealing, leading high water discharge, leading strong support, strong initial support as the core of high speed large section tunnel construction technology, combined with Daliang tunnel high ground stress thin layer slate large deformation control problem. Based on the field test of in-situ stress and the experimental analysis of surrounding rock characteristics, it is concluded that the horizontal in-situ stress is higher than that of vertical geostress. The ratio of strength to stress of surrounding rock is in the range of 0.025 ~ 0.126, which reveals that the deformation of thin layer slate section of Daliang tunnel is large and extruded, and puts forward that the large deformation of thin-layer slate tunnel with high in-situ stress can be divided into serious and large deformation. Medium large deformation, slight large deformation and no large deformation 4. 4) through the field test and numerical simulation analysis of the system anchor rod. It is concluded that the effect of bolt in thin layer slate Vc-2) system is not obvious. Through the comparison test of single-layer grille, single-layer H175 steel and grille I20 steel double-layer support. The results show that the best deformation control effect is double-layer support, followed by single-layer H175 steel, single-layer grille worst in the serious large deformation section, select gradually enhanced support parameters and reserve deformation of the four test sections. A reasonable reserve deformation of 50 cm was put forward, and a large number of tunnel deformation data were statistically analyzed. It is verified that the reserved deformation amount has a probability of more than 95% and no invasion limit. 6) the method of mixing the engine intake nitrogen gas with the plateau environment experimental cabin is verified. Completed the diesel engine performance plateau tunnel environment simulation test platform design and construction. The quantitative evaluation of power mechanical efficiency in plateau tunnel construction environment is obtained, which provides support for the equipment matching and mechanical quota improvement of plateau tunnel construction.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U455.4

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