锦屏二级深埋隧道大理岩段突水破坏机理研究

发布时间：2018-01-03 22:31

本文关键词：锦屏二级深埋隧道大理岩段突水破坏机理研究　出处：《成都理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：锦屏二级深埋隧道位于四川省凉山彝族自治州木里、盐源、冕宁三县交界处的雅砻江锦屏大河湾处，其深埋引水隧道平均长度16.67km，横穿锦屏山河间地带，具有“埋深大、洞线长、洞径大”的特点。工程区域内可溶岩分布广，岩溶发育，岩溶储水丰富，导致工程开挖后诱发产生大量突水灾害，对人员和财产安全造成巨大威胁。本文通过对锦屏二级深埋隧道工程地质条件、水文地质条件及深埋隧道突水灾害特征进行分析，建立了锦屏二级深埋隧道大理岩突水破坏机制概念模型。根据概念模型理论，利用成都理工大学自行研制的大型岩石高压渗透试验仪进行了一系列的岩石高压破坏及高压渗透试验，并通过理论推导得到大理岩突水破坏的力学分析模型。最后结合力学分析模型和数值模拟深入研究了锦屏二级深埋隧道突水破坏机理。论文主要研究成果如下： 1.锦屏二级深埋隧道突水破坏受多种因素影响。其中，隧道开挖人工扰动是主要诱因，高地应力高水压条件是突水破坏发生的必要条件，岩石的自身渗透特性改变是突水破坏发生的内因。通过对岩石突水破坏概念模型的分析得出，，高地应力、高水压力和大理岩渗透特性是研究区内突水破坏的三个主要影响因素。 2.试验结果表明：围岩压力越高，渗透压越高，岩石越容易发生突水破坏。渗透压升高不仅会提升裂隙、孔隙内水压力，还会降低岩石的峰值强度，促进岩体破坏。高压水在岩石变形破坏的不同阶段具有不同的作用，在岩石进入裂纹稳定扩展后，高压水对岩石有一定的保护作用，引导岩石通过形变抵抗岩石应力增加，但仅能延长岩石破坏的时间，对提高岩石的峰值强度影响不大。且随着水压值升高岩石的破坏模式逐渐由剪切破坏为主导转化为由压致拉裂破坏为主导。当岩石内部裂隙扩展贯通后，高压水加速岩石破坏，降低岩石的残余强度值。这在一定程度上解释了岩体突水破坏的滞后性和突发性。 3.通过建立大理岩突水破坏单元体新生裂隙力学分析模型，结合岩样单元体在试验中中的受力条件，并将高压水引入受力分析。通过三种不同的岩石裂纹扩展准则判定，证明裂隙内部有高压水填充时，裂隙的应力状态更加稳定。 4.使用有限元模拟方法对锦屏二级深埋隧道工程区内的地应力条件及开挖过程中隧道应力演化过程进行分析得到：隧道范围内白山组区域的应力条件高于岩塘组和杂谷脑组，初始状态下白山组最大第一、第三主应力分别为65MPa和13MPa；开挖过程中除T3区域的第一主应力值明显下降外，其余区域应力随开挖深度增大而升高。 5.结合试验、力学分析模型及数值模拟三方面的研究，大理岩突水破坏机理可以概括为：隧道开挖后，大理岩在高地应力高水压条件下发生应力场、渗流场重分布，围岩应力集中加剧，渗流通道内水压力升高。随着压力值的升高，岩体进入塑性变形阶段，由于高压水的作用，岩体产生大量微裂隙抵抗形变，延长岩体破坏的时间，同时岩体结构趋于碎裂化。最终岩体完全破坏，破碎的岩体随高压水一同冲出形成突水。
[Abstract]:Jinping two deep buried tunnel in Sichuan Yi Autonomous Prefecture in Liangshan province Muli, Yanyuan, Jinping Yalong River Bay at the junction of three Mianning County Office, the deep buried tunnel of average length of 16.67km, across the Jinping land area, with the depth, hole length, hole diameter characteristics ". Within the project area can be karst distributes widely, karst, karst water rich, leading to the project after the excavation induced large inrush of water disasters, poses a great threat to the safety of persons and property.
This article through to the Jinping two level deep engineering geological conditions of tunnel, hydro geological conditions and the characteristics of deep buried tunnel water bursting disaster analysis, the establishment of the Jinping two level deep tunnel water inrush marble failure mechanism conceptual model. According to the conceptual model theory, from the large rock high pressure permeability test instrument for the development of rock damage and high pressure a series of high pressure permeability test using the Chengdu University of Technology, and damage mechanics analysis model of marble water inrush through theoretical derivation. Finally combining with mechanical model and numerical simulation research of Jinping two deep buried tunnel water bursting failure mechanism.
The main research results of this paper are as follows:
1. Jinping two deep tunnel water inrush damage is affected by many factors. Among them, the artificial disturbance is the main cause of tunnel excavation, high stress and high water pressure condition is a necessary condition for the occurrence of water inrush damage, rock permeability change is its water bursting failure. Through the analysis of internal damage model of rock water inrush concept that high stress, high water pressure and seepage characteristics of marble are three main influential factors in the research area of water inrush from destruction.
2. test results show that the surrounding rock pressure is high, the osmotic pressure is higher, the more prone to sudden water rock damage. The increase of osmotic pressure will not only enhance the fracture pore water pressure, but also reduce the peak strength of rock, promote the rock failure. High pressure water has different roles in different stages of rock deformation and failure in rock entry stable crack growth, high pressure water has a protective effect on the rock rock rock deformation resistance by lead stress increases, but can only prolong the time of rock failure, did not improve the peak strength of rock. And with the influence of hydraulic pressure increased gradually from the failure mode of rock shear failure leading into compressioncracking damage as the leading rock. When the crack propagation through high pressure water, accelerate the failure of rock, reduce the residual strength of rock. This explains the lag of the damage of the rock water inrush in a certain extent And sudden.
3. an analysis model failure unit new fractures mechanics marble water inrush, combined with the sample unit in the test of the stress condition, and the force analysis of the introduction of high pressure water. By three different criteria of rock crack propagation, crack proof internal high pressure water filling, the fracture stress state is more stable.
4. using the finite element simulation method of Jinping two deep buried tunnel engineering stress conditions in the region and in the process of tunnel excavation stress evolution analysis: the tunnel within the scope of the Baishan regional stress conditions is higher than that of rock Tang Group and Zagunao group, the initial state of Baishan group the first third principal stress respectively 65MPa and 13MPa; in the process of excavation in the first principal stress T3 region decreased significantly, the regional stress increases with the increase of excavation depth.
5. according to the test, the mechanical analysis of three aspects of the model and numerical simulation, the failure mechanism of water inrush of marble can be summarized as follows: after the tunnel excavation, rock stress under high water pressure stress field in the Highlands, the seepage field distribution, stress concentration increased, the seepage channel water pressure increases. With the increase of pressure value rock, entered the stage of plastic deformation, due to the action of the high-pressure water, resulting in a large number of micro cracks of rock mass deformation resistance, prolong the time of rock damage, and rock fragmentation. Rock mass structure tends to be completely destroyed, broken rock with high pressure water together out of the water inrush.

【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U457.2

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