动载下岩石裂纹扩展与破坏机制的三维并行数值模拟研究

岩石动载断裂破坏与其非均匀性、非连续性及应变率效应有关，由于断裂理论的复杂性与物理试验的困难，动载下岩石三维断裂破坏问题更具挑战性。本项目应用细观损伤力学、弹脆性理论与动力有限元方法，引入非均匀概率统计函数，考虑基于应变率的复合强度准则，研究粘弹性边界处理方法，建立基于MPI与OpenMP并行计算的岩石三维动力破坏模拟方法。然后，进一步通过模拟岩石预制三维裂隙动载下的扩展过程，研究均质度、入射应力幅值、历时、裂纹倾角对其扩展方式的影响，特别是动载下裂纹分叉、III型断裂规律。研究岩石三轴动静加载的破坏特征，揭示动静加载相互作用下的岩石破坏模式，探讨动态强度、非均匀性与应变率的关系。最后，以动力扰动下地下洞室破坏问题为背景，模拟隧洞在三维地应力条件下动力扰动响应规律，揭示层理方向、应力波入射角对裂纹起裂与扩展角的影响。本研究对于研究动力扰动岩爆灾害、冲击掘进或爆破开挖问题，都具有重要意义。

Due to heterogeneous properties, discontinuity, non-transparency and strain rate effect, three dimensional rock fracture failure of rock under dynamic loading is of great challenge. Based on the meso-damage mechanics, elasto-brittle theory and dynamical finite element method, statistics functions for rock non-uniform mechanical properties will be introduced into the numerical model. A combined composite strength criterion considering loading strain rate and viscoelastic boundary will be established. High performance computing method by using OpenMP and MPI will be applied to implement the three-dimensional rock dynamic model. Then, numerical specimens containing prefabricated three dimensional fracture subjected to dynamical stresses will be simulated to investigate influence of homogeneous degree, stress amplitude, duration, crack inclination angle on the crack propagation and coalescence, especially crack dynamic bifurcation, type III dynamic load crack propagation mechanism. The failure characteristics of three axis static and dynamic loading well be studied, and the relationship between the dynamical compressive strength, heterogeneity and strain rate is discussed. Finally, the dynamical numerical model will be applied in tunnel instability and failure problems due to dynamic disturbance in mining engineering. Influence of joint distribution, stress wave propagation direction on crack initiation and propagation. This research has important scientific value and application significance to the problem of rock failure induced by dynamical disturbance of blasting, excavation and rock bursts.