水作用下石英云母片岩各向异性响应特征及细观机理研究

The influence of the anisotropy of rock on the deformation and destruction of surrounding rock in tunnel engineering cannot be ignored. At present, there have been many achievements in the physical and mechanical properties, strength criteria and surrounding rock stability of anisotropic rocks, but the studies on the anisotropy of rocks in different water-bearing states are rare. This project intends to select quartz mica schist with obvious slice surface as the research object. The wave velocity, deformation and intensity of the rock velocity, deformation and intensity of the rock wave velocity, deformation and strength of the rock will be studied by using wave velocity test, uniaxial compression and triaxial compression test. By using polarizing microscope and scanning electron microscope, the microstructure information of schist is obtained comprehensively, and the microcosmic mechanism of anisotropy of schist under the effect of water is revealed.The 3d scanning technology is first used to research fracture morphology of schist .And then numerical simulation is adopted to analysis of mechanical response characteristics in the process of deformation and failure by the action of compressibility. By both of methods, compression-shear failure mode of anisotropic schist under the action of water research is discussed. The microcosmic quantitative indexes are introduced to improve existing empirical formula, and the prediction methods for the strength index of anisotropic rocks with the change of water content are proposed. In addition, a transverse isotropic model is established considering the influence of water content. The research results will provide important guiding significance and application value to the stability evaluation and support structure design of tunnel surrounding rock.

岩石的各向异性对隧道工程围岩变形破坏的影响不容忽视，目前关于各向异性岩石的物理力学特性、强度准则、围岩稳定性等已有较多成果，但针对水物化作用下的岩石各向异性动态响应研究尚为少见。本项目拟选取含明显片理面的石英云母片岩作为研究对象，采用波速测试、单轴与三轴压缩试验研究片岩波速、变形、强度各向异性与水含量、成分的响应规律；利用偏光显微镜、扫描电镜全面获取片岩细观组构信息，揭示水作用下片岩各向异性的细观机理；基于三维激光扫描技术，采用分形理论，定量研究片岩压缩破坏后的断裂面形貌特征，并辅以数值模拟手段分析片岩在受压剪切变形破坏过程中的力学响应特征，探讨水作用下各向异性片岩的破坏模式；最后引入细观定量指标，对已有经验公式予以改进，提出随含水量变化的各向异性岩石的强度指标的预测方法，并建立考虑含水量影响的横观各向同性体本构模型。研究成果将对隧道围岩稳定性评价与支护结构设计有重要指导意义和应用价值。

本研究从细观-宏观不同层面，深入开展了含弱面岩石各向异性宏观特征与组构因素的关联性研究，探讨了片岩物理力学各向异性对水的响应规律与机制，并从应用角度构建受压片岩强度、变形的预测模型。首先，总结出片理化岩石的典型细观特征，概化出片理化岩石的细观结构模型。将岩石分为矿物系统和孔隙（裂隙）系统，从两类对象的含量、形态、分布等方面，构建了细观组构指标体系，实现了石英云母片岩组构特征的定量分析。研究了片岩纵波速度对浸水时长的响应规律，构建了片岩的波速圆模型，可用于预测不同传播方向下的纵波速度，并探讨了水与细观结构对片岩波速的影响机制。研究了受压片岩的强度各向异性特征，能量演化特征，变形场演化特征以及片岩力学各向异性对水的响应规律。探讨了岩石力学各向异性的细观机制与水作用机制，构建了各向异性片岩的裂隙扩展方向模型。总结了各向异性片岩的宏观破坏模式，从裂纹演化的角度，利用原始缺陷的滑移开裂模型，推导出岩石沿弱面滑移剪切破坏时的临界应力表达式；考虑岩石的宏观剪切破坏，基于摩尔库伦与最大轴向应变准则，建立了斜交弱面剪切破坏时岩石的抗压强度表达式，从而创建了片理化岩石的破坏准则。将受压片岩的损伤分为由片理面引起的初始损伤和加载引起的损伤，基于横观各向同性弹性模型及微元强度服从Weilbull分布的损伤本构模型，建立了各向异性片岩的损伤本构模型。研究成果将对片理化围岩的稳定性评价与支护结构设计有重要指导意义和应用价值。