基于混合失效模型的含坚硬结核煤体截割SPH模拟

    SPH simulation of pick cutting of coal mass with hard concretions based on hybrid failure model

    • 摘要: 针对采煤截割过程中煤岩大变形与破裂模拟难题,提出一种基于光滑粒子法(SPH)的数值模型。融合Drucker-Prager屈服准则与Grady-Kipp模型,构建可同步表征剪切与拉伸失效行为的混合失效模型,完成了Fortran求解程序开发。通过引入人工应力、应力光滑与黏性边界等技术,有效抑制应力振荡与边界反射噪声,提高了数值稳定性。结果表明,模型能够复现预裂缝岩样压缩及单截齿贯入试验中的裂纹扩展路径与破坏模式,验证了其在不同加载方式下裂纹动态扩展模拟能力。模拟了单个截齿切割含坚硬结核煤体破裂过程,揭示了不同切入深度下煤体变形破裂与结核成块剥落的力学机制,识别出以剪切和张拉为主导的两种结核剥落模式。

       

      Abstract: To address the challenges in simulating large deformation and fracture behavior of coal rock during coal cutting, this paper proposes a numerical analysis method based on the smoothed particle hydrodynamics (SPH) approach and a hybrid failure model. This method integrates the Drucker-Prager yield criterion and the Grady-Kipp damage model to establish a hybrid failure mechanism capable of simultaneously describing shear and tensile failure. A Fortran solver is developed accordingly. By incorporating techniques such as artificial stress, stress smoothing, and viscous boundaries, stress oscillations and boundary reflection noise in the calculations are effectively suppressed, enhancing numerical stability. The results demonstrate that the model accurately reproduces crack propagation paths and failure modes in pre-cracked rock compression tests and single pick penetration experiments, verifying its reliability in simulating dynamic crack propagation under different loading modes. Furthermore, the model is applied to simulate linear and rotational cutting processes of a pick, revealing the mechanical mechanisms of coal deformation, fracture, and the blocky spalling of concretions under different penetration depths. Two dominant spalling failure modes, shear-dominated and tensile-dominated, are identified, along with their variation patterns with depth.

       

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