基于结构面原位测量的复杂节理煤体变形破坏机理研究

In coal mining process, coal roadway is faced with the discontinuities-controlling failure problems such as coal fragmentation, separation, roof fall and bolt shear break. However, the mechanical behavior study of coal mining has not systematically considered the influence of coal discontinuities. To solve the discontinuities-controlling failure problems in coal roadway, the scientific issue of deformation and failure mechanism of complex jointed coal mass has been proposed and focused on in this project. First, the three-dimensional model of discrete fracture network (DFN) of jointed coal will be created by means of discontinuities in-situ measurement and the Monte-Carlo stochastic simulation. Second, the numerical model of complex jointed coal mass will be constructed by using the PFC3D-based synthetic rock mass (SRM) method. The physical models of complex jointed coal mass will also be prepared by using the developed physical model making method of complex jointed rock, which integrates 3D printing with chemical dissolution. Then, compression and shear tests under different loading orientations and confining pressure/normal stress will be performed on the constructed numerical and physical models. Finally, through comparison and summary of the numerical and physical results, the deformation and failure characteristics of jointed coal under compression and shear will be clarified, the influencing mechanism of the coal DFN on compression and shear failure of jointed coal will also be revealed. The results will contribute to solving the discontinuities-controlling failure problems of coal roadway and promoting the refined research of coal mining.

煤炭开采过程中煤巷面临煤体碎裂、离层、冒顶与锚杆剪断等结构面控制性破坏难题，而目前煤炭开采力学行为研究尚未系统考虑煤体结构面的影响。为解决煤巷结构面控制性破坏难题，本项目提炼并围绕复杂节理煤体变形破坏机理这一科学问题，首先，采用结构面原位测量与蒙特卡罗随机模拟方法建立煤体结构面网络三维模型；其次，基于PFC3D软件，利用合成岩体方法构建复杂节理煤体数值模型，开发基于3D打印技术与化学溶解原理的复杂节理岩体物理模型制作方法，制备复杂节理煤体物理模型；然后，针对复杂节理煤体数值模型与物理模型，采用数值模拟与物理模拟互相验证的方法，开展不同加载方位、不同围压/正应力的压缩与剪切试验；最后，对比总结数值试验与物理试验结果，阐明压缩与剪切条件下复杂节理煤体的变形破坏特征，揭示结构面网络对煤体压缩与剪切破坏的影响机理。研究成果有助于解决煤巷结构面控制性破坏难题、推动煤炭开采的精细化研究。

煤炭开采过程中煤巷面临煤体碎裂、离层、冒顶与锚杆剪断等结构面控制性破坏难题，而目前煤炭开采力学行为研究尚未系统考虑煤体结构面的影响。为解决煤巷结构面控制性破坏难题，本项目提炼并围绕复杂节理煤体变形破坏机理这一科学问题，综合采用实验室试验、数值模拟、现场试验等方法系统研究了煤体结构面原位测量与结构面网络三维模型构建方法、复杂节理煤体数值模型构建与物理模型制作方法以及压缩与剪切条件下复杂节理煤体变形破坏特征与机理。通过本项目研究，形成了煤矿井下煤体结构面的实用高效原位测量方法，以及煤体结构面网络三维模型的构建方法，有助于实现煤矿工程和岩土工程的精细化建模，可在工程稳定性分析中系统考虑结构面的影响；开发出基于3D打印技术与化学溶解原理的复杂节理岩体物理模型制作方法，既可确保模型主体为强度可控的常规砂浆，又可包含复杂结构面网络，使裂隙岩体的物理模拟能力扩展至复杂裂隙岩体；阐明了压缩与剪切条件下复杂节理煤体变形破坏特征，揭示了结构面网络对复杂节理煤体变形破坏的影响机理，可为裂隙岩体力学行为分析提供理论参考。研究成果有助于解决煤巷结构面控制性破坏难题、推动煤炭开采的精细化研究。特别是本项目开发的复杂裂隙岩体物理模型制作方法可用于裂隙岩体工程的物理模拟研究，丰富了裂隙煤岩体的研究手段。