模拟节理岩体破裂过程的三维非连续数值模型研究

Simulating the fracturing process of 3D jointed rock masses is not only a scientific challenge for the computational rock mechanics, but a technical problem to be urgently solved for the prevention and treatment of geological/engineering disasters, and for the energy/resource exploitation. This study is an extension of the two previously completed NSFC projects with the approval numbers of 50479071 and 40972201, respectively. By applying theoretical analysis, algorithm formulation, programing and test verification, this project supposes to perform study on the following aspects: the automatic discretization of interest domain with tetrahedron mathematical covers, the automatic generation of 3D physical covers (boundaries, joints, lithological interfaces, etc.), and the topological calculation/generation of the manifold elements; the algorithms for speedy searching and effective contact determination amongst massive tetrahedron elements; a DDARF-NMM model for calculating the fracturing of element interfaces; the assemblage of the global stiffness matrix and the solution of the large-scale algebraic equations; VC++ code programing and debugging; the tensile and compressive tests of 3D similar-material samples with pre-cracks, etc. Within the framework of the classical numerical manifold method, this study aims to reproduce the whole macro process of crack initiation, propagation, coalescence and rock fragmentation through simply connecting and disconnecting the linkages amongst microscopic elements, to build up a 3D discontinuum-based numerical model for simulating rock masses with existing structural interfaces, and to provide a robust numerical tool for unveiling the mechanism of fracturing disaster evolution, as well as improving the pertinence of preventive and controlling technology.

模拟三维节理岩体的破裂过程是计算岩石力学面临的科学挑战，也是地质和工程灾害防治、能源和资源开发领域亟需解决的技术难题。本研究是结题的基金项目50479071和40972201的延伸。拟采用理论分析、算法推演和编程、试验验证等手段，研究如下内容：四面体数学覆盖的自动剖分、三维物理网格(边界、节理、岩性交界面等)的自动生成以及三维流形单元的拓扑计算和生成方法；海量四面体单元的快速搜索和高效接触判断算法；沿界面开裂的DDARF-NMM计算模式；总刚矩阵的装配和大规模方程组的求解方法；VC++程序编制和调试；三维含预制裂纹的相似材料试样拉、压试验等。目标是在经典数值流形方法的框架中，通过细观层次简单的界面粘接和开裂，模拟宏观层次的裂纹萌生、扩展、贯通乃至岩体破碎的全过程，建立模拟含原生断续结构面岩体的三维非连续数值理论模型，为揭示岩体工程断裂灾害的孕育机理、提高防控技术的针对性提供数值工具。

基于四面体单元的三维数值流形方法和细观层次界面的黏结-破裂模型，提出了模拟断续节理岩体渐进破坏过程的三维数值流形方法，采用c++编程语言开发了三维节理岩体破裂模拟软件，完成节理岩体建模、破裂分析和图形显示功能。建模模块实现了四面体单元数学覆盖的自动剖分、三维物理网格的自动生成，三维流形单元的生成和随机及确定结构面的模拟；力学分析模块实现了海量四面体单元、凸多面体单元和任意多面体单元的快速搜索和高校接触判断算法，沿单元界面开裂的黏结-破裂模型，总刚度矩阵的装配和方程组的求解算法；后处理模块实现了破裂过程的动态显示，单元速度和应力应变的显示。首先验证了运动学基础算例，同时开展了基于岩体相似材料的预制裂纹试样单轴压缩室内模拟试验，用以验证数值模型和校正细观模型参数，并初步应用在岩体边坡破坏和节理岩柱破坏的模拟中。本项目所建立的三维节理岩体破裂模拟方法可应用在地质和工程灾害防治、能源和资源开发领域，为岩体工程断裂灾害的孕育机理、提高防控技术，优化地下空间利用及提高能源开采效率提供针对性的数值工具。基于本项目所取得的研究成果，出版专著2部，发表SCI收录论文10篇，EI论文1篇。取得授权发明专利3项，国家软件著作权 3项，另目前还有3项软件著作权处于受理阶段。开发三维破裂模拟软件 1 套。获得国家科技进步二等奖1项，项目负责人在基金资助下，入选百千万人才工程国家级人选，国家有突出贡献中青年专家，国务院政府特殊津贴专家。兼任国际主流SCI杂志《International Journal of Geomechanics-ASCE》共同主编。指导相关研究方向博士生6人，其中已毕业3人。