深埋隧洞开挖损伤区的演化与形成机制研究

发布时间：2018-04-26 01:25

本文选题：深部 + 隧洞　；参考：《东北大学》2013年博士论文

【摘要】：深埋隧洞开挖围岩损伤区的演化与形成一直以来是岩石力学、实验力学、损伤力学、断裂力学与构造地质等多学科互相交叉而复杂的科学问题。随着岩石工程不断向纵深发展,地质灾害频发,开展高应力下深部地质灾害孕育机制的研究备受关注,而地质灾害的孕育伴随着围岩的损伤演化,特别是深部岩体开挖卸荷条件下岩石的宏细观损伤演化规律,大型岩体围岩损伤区的综合原位测试方法,岩体埋深、隧洞尺寸、开挖方式、开挖速率等因素对开挖损伤区形成的影响以及演化机制、岩体损伤的预测与支护时间的确定已成为深部地下工程开挖中待解决的关键性问题。基于此,本文遵循从现象到本质,从局部到整体,从细观到宏观,从原位试验到数值分析的研究路线,分析钻爆法开挖和TBM开挖方式下深部岩体损伤破坏特征、动态响应规律和形成机制,开展的主要研究工作如下：(1)针对深埋隧洞开挖损伤区的测试,提出了基于开挖损伤区弹性波测试、数字钻孔摄像、滑动测微计变形测试、微震和声发射微破裂信号定位等优势互补的原位试验综合测试方法,阐释了开挖损伤区的测试原理,给出了试验场址的选择原则,试验平台的搭建方法,钻孔的布置依据,测试试验流程,以及试验设备的安装调试和数据处理方法,弥补了单一测试方法不能保证测试结果的有效性,施工方式的多样性,以及深部复杂岩体力学信息响应的完备性,并以锦屏二级水电站深埋试验洞开挖损伤区的测试试验为实例进行了原位试验设计。(2)岩芯饼化的形成是深部岩体局部应力解除下岩石的损伤演化过程。在总结岩芯饼化宏观断口形貌类型的基础上,给出了岩芯饼化数量,饼化岩芯厚度沿钻孔方向的分布规律,进一步分析了岩体埋深、地质结构、开挖损伤、钻孔直径大小和方向,以及钻进速度等因素对岩芯饼化的影响。通过对不同直径、不同厚度、不同凹凸面和不同位置的饼化岩芯断口进行SEM电镜扫描,分析了岩芯饼化的细观力学机制。(3)针对钻爆法开挖方式下深埋隧洞开挖损伤区的演化与形成机制,在了解爆破破岩机理的基础上,基于深埋科研试验洞的开挖,总结了钻爆法开挖洞壁损伤破坏模式及成因。考虑不同埋深、隧洞尺寸和开挖方式,通过数字钻孔摄像技术手段,分析了岩体损伤裂隙特征,裂隙产状开挖前后的变化规律,裂隙宽度随开挖进程和时间的演化规律,以及新生裂隙沿钻孔轴向的分布规律。通过声波测试,得到不同时间下岩体波速沿钻孔方向分布,并给出孔底段岩体平均波速随掌子面的变化关系。通过滑动测微计变形测试,给出了岩体变形随开挖时间和进尺的变化关系。通过微震监测,得到微震时间、能量指数和视体积随时间的变化关系,以及微震事件随掌子面推进的演化规律。给出了基于以上信息的分析思路,形成了钻爆法开挖方式下开挖损伤区的演化与形成机制,并分别给出掌子面对其在隧洞轴向与径向影响范围,以及时间影响效应,为深埋隧洞钻爆法开挖支护设计提供建议。(4)针对TBM开挖方式下深埋隧洞开挖损伤区的演化与形成机制,在了解TBM破岩机理的基础上,基于深埋科研试验洞的开挖,通过数字钻孔摄像测试,分析了原岩岩体结构特征,开挖过程岩体裂隙损伤特征,以及新生裂隙产状与隧洞轴向的关系,着重分析了裂隙宽度随开挖进程和时间的演化规律。通过声发射试验,得到声发射事件数和事件能量随掌子面推进在隧洞径向和轴向方向的演化规律。通过多个钻孔单孔声波测试,得到不同钻孔的损伤深度。综合以上信息,结合围岩应力状态和应力应变曲线,研究了TBM开挖方式下开挖损伤区的演化与形成机制,并分别给出TBM开挖对隧洞轴向与径向的影响范围,以及时间效应,为深埋隧洞TBM法开挖支护设计提供建议。(5)基于数值模拟手段分析了围压对隧洞初始损伤和临界破坏状态的影响,以及隧洞尺寸对围岩变形的影响；并利用原位试验和其它测试结果进行围岩参数反演,应用损伤劣化本构模型,建立深埋隧洞数值计算模型,对比分析数值模拟结果与现场围岩破坏,验证RDM损伤劣化本构模型、力学参数和FAI评价方法的合理性。
[Abstract]:The evolution and formation of the surrounding rock damage zone in deep buried tunnels has been a complicated scientific problem that intersected and intersected with rock mechanics, experimental mechanics, damage mechanics, fracture mechanics and tectonic geology. With the continuous development of rock engineering, geological disasters occur frequently, and the mechanism of deep geological disasters under high stress is studied. The gestation of geological disasters is accompanied by the damage and evolution of the surrounding rock, especially the macro and mesoscopic damage evolution of rock under the unloading condition of deep rock mass excavation, the comprehensive in situ testing method of the large rock mass surrounding rock, the depth of the rock mass, the size of the tunnel, the mode of excavation, the excavation rate and so on. And the evolution mechanism, the prediction of rock mass damage and the determination of support time have become the key problems to be solved in the excavation of deep underground engineering. Based on this, this paper follows the research route from the phenomenon to the essence, from the local to the whole, from the meso to macro, from the in-situ test to the numerical analysis, and analyzes the deep and deep excavation method under the excavation method and the TBM excavation method. The main research work is as follows: (1) according to the test of the excavation damage area of the deep buried tunnel, the advantages of the elastic wave test based on the excavation damage zone, the digital borehole camera, the sliding micrometer deformation test, the micro earthquake and the acoustic emission micro rupture signal location are put forward. The test comprehensive test method has explained the testing principle of the excavation damage area, gives the selection principle of the test site, the construction method of the test platform, the basis of the drill hole layout, the test process, the installation, debugging and data processing methods of the test equipment, and make up for the validity of the single test method, which can not guarantee the validity of the test results. The diversity of the type and the completeness of the mechanical information response of the deep complex rock mass, and in situ test design is carried out with the test test of the excavation of the deep buried test hole in the two stage of Jinping hydropower station. (2) the formation of the core cake formation is the damage evolution process of the rock under the local stress relieving of the deep rock mass. On the basis of the type of mouth shape, the number of core cake and the distribution law of the thickness of the cake core along the direction of the borehole are given. The influence of the depth of the rock mass, the geological structure, the excavation damage, the diameter and direction of the drill hole, the drilling speed and other factors on the core cake are further analyzed. The micromechanical mechanism of the core cake is analyzed by SEM scanning electron microscope in the same position. (3) in view of the evolution and formation mechanism of the damaged area in the deep buried tunnel excavation under the drilling and blasting excavation method, based on the understanding of the blasting rock breaking mechanism and the excavation of the deep buried research test hole, the damage and failure of the tunnel wall excavation are summed up. Mode and cause. Considering different buried depth, tunnel size and excavation way, the characteristics of rock mass damage fracture, the law of changes before and after excavation, the evolution law of fracture width along with the excavation process and time, and the distribution law of the new crack along the borehole axis are analyzed by digital borehole photography. At different time, the wave velocity of rock mass is distributed along the direction of drilling, and the relation between the average wave velocity of the rock mass in the bottom of the hole and the change of the hand surface is given. By the deformation test of the slide micrometer, the relationship between the deformation of rock mass with the excavation time and the change of the length is given. The evolution and the formation mechanism of the excavation damage area under the drilling and blasting method are formed, and the effect of the influence on the axial and radial direction of the tunnel, as well as the time effect effect are given respectively, for the excavation and support of the deep buried tunnel. Suggestions are provided. (4) in view of the evolution and formation mechanism of the damaged area in the deep buried tunnel under TBM excavation, based on the understanding of the mechanism of TBM rock breaking, the structure characteristics of the rock mass, the fracture damage characteristics of the rock mass, and the occurrence of the new fissure in the excavation process are analyzed on the basis of the excavation of the deep buried research test cave and the digital borehole camera test. The relationship between the axial direction of the tunnel and the evolution law of the crack width with the process and time of the excavation are emphatically analyzed. Through the acoustic emission test, the evolution law of the number of acoustic emission events and the event energy in the radial and axial direction of the tunnel with the hand surface is obtained. The damage depth of different boreholes is obtained through the sound wave test of multiple boreholes. Information, combining the stress state of surrounding rock and stress strain curve, the evolution and formation mechanism of the excavation damage area under the excavation of TBM is studied, and the influence range of TBM excavation on the axial and radial direction of the tunnel and the time effect are given respectively, and the suggestion for the design of the excavation and support of the deep buried tunnel by TBM method is proposed. (5) the confining pressure is analyzed based on the numerical simulation method. The influence of the initial damage and critical failure state of the tunnel and the influence of the tunnel size on the deformation of the surrounding rock, and the inversion of the surrounding rock parameters by the in-situ test and other test results, the numerical model of the deep buried tunnel is established by the damage deterioration constitutive model, and the results of the numerical simulation and the damage of the surrounding rock are compared and analyzed, and the RDM damage is verified. The deterioration constitutive model, the mechanical parameters and the FAI evaluation method are reasonable.

【学位授予单位】：东北大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU45

【参考文献】