爆破-地下水协同作用下板岩隧道围岩劣化机制研究

On the field with rich groundwater and at the slate tunnels, evacuated by the drilling and blasting method, the coordinating effect of blasting and groundwater on the surrounding rock leads the rock suffers deterioration, affecting the engineering stability. This topic sets the slate tunnel as the research object, the blasting and rich water environment as the action factor, applying the combination of the site tests, the indoor experiments, the real material model tests and the theories analysis to study the slate deterioration mechanism of the coordinating effect of blasting and groundwater. To begin with through the site acoustic tests and the drill-hole camera measures, the surrounding rock damage fracture distribution rules of the surrounding rock affected by the coordinating effect of blasting and groundwater are achieved; next through the dynamic monitoring of stress, the macroscopic evolution rules of the surrounding rock deformation are studied; then through the blasting vibration tests, the characteristic of the dynamic parameters of surrounding rock are mastered; further through the X-ray energy spectra mineral analysis and the microscopic CT non-destructive testing technology, the mesoscopic evolution rules of the surrounding rock micro parameters are analyzed; moreover through the water absorption tests and the WRR chemistry tests, the physicochemical evolution mechanism of the surrounding rock deterioration is explored; what’s more with the real material model tests and the ANSYS/LS-DYNA dynamic FEM analysis, the mechanics evolution mechanism of the surrounding rock is achieved. The contribution and the ratio of each deterioration factor to the slate deterioration are determined, to establish the deterioration degree functions for the relations between the slate mechanics parameters and the deterioration factors and further to establish the degradation prediction model. The research results can reveal the mechanism of the soft surrounding rock deterioration of slate tunnel under the coordinating effect of the blasting and groundwater, and provide theoretical basis for revising the tunnel structure design code and guiding design and construction for slate tunnel in rich water area.

在富含地下水地区钻爆开挖板岩隧道时，爆破与地下水协同作用下的隧道围岩易遭受劣化作用，影响工程稳定性。以板岩隧道为研究对象，以爆破及地下水为作用因子，采用现场试验、室内试验、模型试验与理论分析相结合的方法，开展爆破-地下水协同作用下板岩隧道围岩劣化机制研究。通过声波测试、孔内摄像测量，获取围岩损伤裂隙的展布规律；借助应力及变形监测，研究围岩变形宏观演变规律；基于现场爆破振动测试，掌握围岩动力参数变化特征；采用X射线能谱矿物分析、显微CT无损伤探测等方法，分析围岩劣化的微细观演变规律；基于吸水膨胀、水岩化学等试验，探寻围岩劣化的理化机制；通过真实材料模型试验并结合动力有限元程序，获取围岩劣化的力学机制。构建板岩隧道围岩力学参数与劣化因子之间的劣化度函数，建立劣化预测模型，揭示爆破-地下水协同影响下板岩隧道围岩劣化机制，为修订完善隧道结构设计规范，指导富水地区板岩隧道设计和施工提供理论基础。

随着我国在地下水丰富地区采用钻爆法开挖隧道数量的不断增加，对爆破-地下水协同作用下板岩隧道围岩性质劣化演变机理这一科学问题展开研究，对丰富理论研究与指导工程实际具有较大的科学意义。以板岩隧道围岩性质劣化机理为研究中心，以爆破作用及赋存富水环境为工程背景，通过现场调查、理论分析、现场试验、室内试验、数值模拟等研究手段，从微细观、宏观、理化、力学等层面，开展了爆破-地下水协同作用下板岩隧道围岩性质劣化机理研究。通过开展岩石薄片（切片）偏光显微镜试验，分析了不同工况下板岩的微观结构、胶结类型、矿物颗粒排列情况，获取了板岩微观结构劣化规律。通过多功能X-射线衍射（XRD）试验，分析了板岩矿物成分及含量的变化情况，揭示了板岩矿物成分微观劣化规律。通过环境扫描电子显微镜试验，分析了板岩表面形貌细观特征，揭示了板岩表面形貌细观劣化规律。采用离散格子弹簧元模型，模拟了板岩细观断裂扩展行为，揭示了板岩的细观断裂劣化规律。通过密度试验、电阻率试验、耐崩解性试验、现场波速测试，揭示了板岩的物理劣化机理。开展了干燥板岩室内饱水试验、室内X射线能谱试验，揭示了爆破-地下水协同作用下板岩的化学性质的劣化规律通过开展现场爆破振动测试、现场变形监测，建立了宏观振动劣化模型及宏观变形劣化模型。开展了室内三轴压缩力学试验、现场径向液压枕抗力试验，揭示了板岩抗力性质的劣化机理。建立了爆破-地下水协同作用的劣化板岩强度定量确定方法并应用于具体工程实际，对劣化后的隧道围岩强度展开分析和计算。