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<p>Concrete-sandstone composite structures are commonly used for roadway support in underground coal mining engineering. Dynamic impact simulations using the split Hopkinson pressure bar (SHPB) were performed in LS-DYNA software for concrete strengths of 25&#xa0;MPa, 30&#xa0;MPa, and 35&#xa0;MPa. This study investigates the effects of concrete strength and confining pressure on crack propagation dynamics and damage evolution in a concrete-sandstone composite. The characteristics of stress–strain curves, crack propagation, and damage evolution of concrete-sandstone composite were analyzed under an impact velocity of 14&#xa0;m/s. The simulation results identified three distinct stages in the stress–strain curve of the composite: elastic deformation, plastic deformation, and post-peak damage. With increasing confining pressure and concrete strength, crack propagation extended from the concrete component to the sandstone component, shifting from unidirectional to multi-directional behavior. At constant concrete strength, increased confining pressure reduced damage in the concrete component while increasing damage in the sandstone, reducing overall composite damage. At constant confining pressure, increased concrete strength reduced damage in the concrete component but increased damage in the sandstone, resulting in higher overall composite damage. When concrete strength and confining pressure are low, the concrete primarily absorbs the energy, acting as the main energy dissipation body. Conversely, at higher concrete strength and confining pressure, the concrete accumulates and transfers energy, rendering sandstone the primary energy dissipation body. This study is crucial for optimizing concrete materials and ensuring structural stability in roadway support for underground engineering.</p>

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Numerical analyses of dynamic crack propagation and damage evolution in concrete-sandstone composite under confining pressure

  • 期刊论文

  • 发表日期：

    2025年12月6日

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  • Pu Yuan,
  • Yunda Dong,
  • Aobo Li,
  • Xiaobo Zheng

摘要

Concrete-sandstone composite structures are commonly used for roadway support in underground coal mining engineering. Dynamic impact simulations using the split Hopkinson pressure bar (SHPB) were performed in LS-DYNA software for concrete strengths of 25 MPa, 30 MPa, and 35 MPa. This study investigates the effects of concrete strength and confining pressure on crack propagation dynamics and damage evolution in a concrete-sandstone composite. The characteristics of stress–strain curves, crack propagation, and damage evolution of concrete-sandstone composite were analyzed under an impact velocity of 14 m/s. The simulation results identified three distinct stages in the stress–strain curve of the composite: elastic deformation, plastic deformation, and post-peak damage. With increasing confining pressure and concrete strength, crack propagation extended from the concrete component to the sandstone component, shifting from unidirectional to multi-directional behavior. At constant concrete strength, increased confining pressure reduced damage in the concrete component while increasing damage in the sandstone, reducing overall composite damage. At constant confining pressure, increased concrete strength reduced damage in the concrete component but increased damage in the sandstone, resulting in higher overall composite damage. When concrete strength and confining pressure are low, the concrete primarily absorbs the energy, acting as the main energy dissipation body. Conversely, at higher concrete strength and confining pressure, the concrete accumulates and transfers energy, rendering sandstone the primary energy dissipation body. This study is crucial for optimizing concrete materials and ensuring structural stability in roadway support for underground engineering.