High-energy gas fracturing of shale is a novel, high efficacy and eco-friendly mining technique, which is a typical dynamic perturbing behavior. To effectively extract shale gas, it is important to understand the dynamic mechanical properties of shale. Dynamic experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this research. The dynamic stress-strain curves, peak strain, peak stress and failure modes of shale are investigated. The results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors, although this effect decreases as the strain rate increases. The characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates, which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial compression. Additionally, a numerical three-dimensional Split Hopkinson Pressure Bar (3D-SHPB), which is established by coupling PFC3D and FLAC3D methods, is validated to replicate the laboratory characteristics of shale. The dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D method. The numerical results are in good agreement with the experimental data.

中文翻译：

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高应变率真三轴压缩页岩动态力学行为实验与数值研究

页岩高能气体压裂是一种新型、高效、环保的开采技术，是一种典型的动态扰动行为。为了有效地开采页岩气，了解页岩的动态力学特性非常重要。本研究首次对不同应变率下的页岩进行真三轴压缩动态实验。研究了页岩的动态应力-应变曲线、峰值应变、峰值应力和破坏模式。研究结果表明，中间主应力和次主应力对动态力学行为有显着影响，尽管这种影响随着应变率的增加而减弱。压剪破坏特征主要发生在高应变率三轴压缩的页岩中，这与页岩在动态单轴压缩下观察到的破碎特征不同。此外，通过耦合 PFC3D 和 FLAC3D 方法建立的数值三维分割霍普金森压力棒 (3D-SHPB) 经验证可以复制页岩的实验室特征。采用PFC3D与FLAC3D耦合方法系统研究了页岩在不同围应力作用下的动态力学特性。数值结果与实验数据吻合良好。