基于哈密顿力学的煤岩冲击损伤演化机理与分析方法

Analytical method and damage evolution mechanism of coal and rock bursting based on Hamiltonian mechanics

  • 摘要: 为了研究突出煤层掘进工作面前方煤体的受载状态和原位煤岩体在静态、动态载荷作用下的非线性力学传递路径,采用哈密顿力学体系建立横观各向同性层状组合煤岩体数学模型,并结合辛空间-时间子域法求解煤岩体的层间动态力学传递路径。通过理论分析研究了采掘扰动应力波的卸载/二次加载过程对掘进工作面前方煤岩体的影响,包括塑性区、弹性区及原岩应力区的应力传递路径与损伤破坏规律。研究结果表明,中心区域会产生应力集中,且沿着短轴和长轴方向的应力衰减;在对角线方向表现出能量衰减和“X”型剪切破坏模式;塑性加载波追赶弹性卸载波,在0.02、0.03和0.06 s时刻塑性区与弹性区煤体之间出现脱层现象,在0.004和0.028 s时刻出现了径向变形引起的脱层现象。基于MC破坏准则和应变能密度分析,研究了“V”型能量坑的分布特征,从而验证了轴向主导、长轴扩展的十字形裂隙的试验现象。

     

    Abstract: In order to study the loading state of the coal body in front of the heading face of the outburst coal seam and the nonlinear mechanical transfer path of the in-situ coal and rock mass under static and dynamic loads, a mathematical model of the transversely isotropic layered combined coal and rock mass was established by using the Hamilton mechanical system, and the symplectic space-time subdomain method was used to solve the interlayer dynamic mechanical transfer path of the coal and rock mass. This study investigates the unloading-reloading process of excavation-induced stress waves and its effects on the coal-rock mass ahead of the tunneling face. The results show central stress concentration with attenuation along the short and long axes, and an "X"-shaped shear failure along the diagonal. Plastic loading waves overtaking elastic unloading waves induce delamination at 0.02, 0.03 and 0.06 s, while radial deformation causes additional delamination at 0.004 and 0.028 s. Analysis based on the Mohr-Coulomb criterion and strain energy density reveals a "V"-shaped energy pit, consistent with experimentally observed cross-shaped fractures dominated by axial propagation and long-axis extension. This study conclusions can provide a theoretical basis for predicting and preventing coal-rock instability.

     

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