• 全部
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
大倾角工作面飞矸冲击破碎特征研究
  • Title

    Fractal characteristics and fracture mechanisms of flying gangue in longwall workings of the steeply dipping seam

  • 作者

    胡博胜伍永平文虎解盘石王红伟

  • Author

    HU Bosheng;WU Yongping;WEN Hu;XIE Panshi;WANG Hongwei

  • 单位

    西安科技大学 能源学院西部矿井开采及灾害防治教育部重点试验室西安科技大学 安全学院

  • Organization
    School of Mineral Engineering, Xi’an University of Science and Technology
    Key Laboratory of Western Mine Exploitation and Hazard Prevention Ministry of Education
    School of Safety Engineering, Xi’an University of Science and Technology
  • 摘要

    飞矸灾害长期威胁大倾角、急倾斜煤层长壁工作面人员和设备安全,单一飞矸迁移过程碰撞破碎衍生出大量“子矸”,其动力损害具有突发性,揭示冲击载荷作用下煤岩体破碎特征是准确掌握飞矸动力损害的重要前提。综合运用分离式霍普金森压杆试验、数值SHPB试验和物理模拟开展冲击载荷作用下煤岩体破碎特征与碎裂机制研究,得到以下主要结论:高速冲击作用下煤岩破坏模式分为相对完整、单一劈裂和完全粉碎,破碎程度随着加载应变率增加而增加,分形维数D与应变率呈对数函数关系。相同应变率水平,煤岩抗压强度越小分形破碎程度越高;煤岩分形维数D与其几何尺度负相关;圆盘和立方体煤岩分形维数D与应变率均呈对数函数关系。立方体煤岩累积碰撞作用下内部节理裂隙发育,应力波传播呈现弥散性,在边缘应力集中并诱发破坏,即不规则形状煤岩外缘易率先与主体破坏分离从而导致其球形度增加。相反,飞矸运动过程棱角处更易受到碰撞而承受直接应力冲击而产生局部崩解。研究成果可为大倾角、急倾斜煤层飞矸灾害防控实践中挡矸网形状以及网格大小的选择提供一定的科学指导。飞矸涉及材料、几何等多源不确定因素,内部层理、裂隙分布及发育程度受开采扰动影响较大,其破碎分形特征更加趋于复杂,下一步将考虑以上因素对飞矸破碎特征的影响。

  • Abstract

    The flying-gangue hazard has long threatened the safety of personnel and mining equipment in steeply dipping/inclined coal seams. A flying gangue maybe produces a large number of “subgangues” after impacting on the longwall floor, it’s damage is sharply increased. Revealing the rupture response and fragmentation mechanism of the flying gangue under dynamic loading is one of the important contents to grasp the characteristics of dynamical damage for flying gangue hazard. This study was carried out through the combination of Split Hopkinson Pressure Bar test, model test and numerical simulation test. The results show: The failure mode of coal-rock under high-speed impact can be divided into three types: intact, single crack, and severe fragmentation. Fractal dimension D the coal specimen has a logarithmic relationship with the strain rate. Coal with lower uniaxial compression strength is more severely broken and has a larger fractal dimension D under the same strain rate conditions. The larger the coal size, the smaller the fractal dimension D is. The fractal dimension D of coal has a logarithmic relationship with strain rate regardless of whether the shape of the specimen is a disk or a cube. The “shape-rounded” phenomenon of the cube block is prone to appear during the movement. This phenomenon can be attributed to three parts: First, because the impact orientation between the block and slope or equipment is not strictly perpendicular compared with a drop test, the stress wave propagation within the specimen is dispersed to some extent during an impact. Second, because the block shape is not strictly regular, the stress is easily concentrated on a non-smooth surface. Finally, due to local shear failure in the contact area, a damaged area is formed. The corners of the flying-gangue are more susceptible to collision and direct loading, resulting in localized disintegration. This study provides a method for risk assessment and for determining the principles of protective systems in underground steep coal seams. In contrast, the flying-gangue involves material, geometry and other sources of uncertainty, stratification, fracture distribution and the degree of development by mining disturbance has a greater impact on the fractal characteristics of its crushing tends to be more complex. In the next step, the effect of the above factors on the crushing characteristics of the flying-gangue will be considered.

  • 关键词

    大倾角煤层飞矸灾害应变率效应分形维数碎裂机制

  • KeyWords

    steeply dipping coal seam;flying-gangue hazard;strain rate effect;fractal dimension;fracture mechanism

  • 基金项目(Foundation)
    国家自然科学基金青年资助项目(52204151);国家自然科学基金重点资助项目(51634007);中国博士后科学基金面上资助项目(2022MD713796)
  • DOI
  • 引用格式
    胡博胜,伍永平,文 虎,等. 大倾角工作面飞矸冲击破碎特征研究[J]. 煤炭科学技术,2024,52(10):1−10. DOI: 10.12438/cst.2023-1322
  • Citation
    HU Bosheng,WU Yongping,WEN Hu,et al. Fractal characteristics and fracture mechanisms of flying gangue in longwall workings of the steeply dipping seam[J]. Coal Science and Technology,2024,52(10):1−10. DOI: 10.12438/cst.2023-1322
  • 相关文章
  • 图表
    •  
    •  
    • 应力波在弹性杆中传递原理

    图(16) / 表(4)

相关问题
立即提问

主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会

©版权所有2015 煤炭科学研究总院有限公司 地址:北京市朝阳区和平里青年沟东路煤炭大厦 邮编:100013
京ICP备05086979号-16  技术支持:云智互联