摘要
随着深部煤炭资源开采强度增大,穿层巷道围岩稳定性问题日益突出。本文以山东霄云煤矿穿层巷道为背景,针对含不同倾角(0°、10°、15°)的煤岩复合结构,设计恒下限(路径Ⅰ)与变下限(路径Ⅱ)循环加卸载试验,结合声发射监测及电镜扫描技术,研究其宏-细观破坏机制。结果表明:(1)循环路径显著影响力学特性,路径Ⅱ因动态应力扰动增强压密效应,峰值应力和应变较路径Ⅰ提升显著;(2)倾角增大导致力学性能劣化,0°试样峰值强度较15°试样提高58.8%,滞回回线面积缩减明显,能量耗散效率下降,脆性破坏加剧;(3)声发射信号与破坏模式呈倾角依赖性,0°试样振铃计数峰值较15°高约50%,事件点沿煤岩界面集中分布,而高倾角试样破坏局部化;(4)微观分析表明,倾角增加使煤体韧窝减少、脆性断裂占比上升,路径Ⅰ分形维数较路径Ⅱ高8.9%,裂纹网络更复杂。研究揭示了穿层倾角与循环路径协同作用下的破坏机制,为深部巷道稳定性评估与灾害防控提供了理论依据。
With the increasing intensity of deep coal resource extraction,the stability of interbedded roadways has become a critical concern.This study focuses on coal-rock composite structures with varying dip angles(0°,10°,15°)from the Xiaoyun Coal Mine in Shandong Province.Two cyclic loading-unloading paths—constant lower bound(PathⅠ)and variable lower bound(PathⅡ)—were designed to simulate static and dynamic stress conditions,respectively.Mechanical behaviors,acoustic emission(AE)signals,energy dissipation,and microstructural damage evolution were systematically investigated using AE monitoring and scanning electron microscopy(SEM).The key findings are as follows.The cyclic stress paths significantly affect mechanical properties.Cyclic loading paths exert a pronounced influence on mechanical properties.PathⅡinduces enhanced compaction effects through dynamic stress perturbations,resulting in significantly higher peak stress and strain compared to PathⅠ.Mechanical degradation correlates with dip angle.The peak strength of 0°specimens exceeds that of 15°specimens by 58.8%,accompanied by a marked reduction in hysteresis loop area,indicating diminished energy dissipation efficiency and heightened brittle fracture.AE characteristics exhibit dip angle dependency.The peak AE ringing counts for 0°specimens are approximately 50%higher than those of 15°specimens,with AE events concentrated along coal-rock interfaces for low-angle specimens,while localized failure dominates at higher angles.Microscopic analysis reveals reduced ductile dimples and increased brittle fractures with higher dip angles.The fractal dimension under PathⅠ(2.31)is 8.9%,which is higher than thar under PathⅡ.It reflects more intricate crack networks under constant lower bound conditions.This research elucidates the synergistic effects of dip angle and cyclic stress paths on failure mechanisms,which will provide theoretical insights for stability assessment and dynamic hazard mitigation in deep interbedded roadways.
作者
彭瑞
沈春阳
刘江
杨学红
郑迪
PENG Rui;SHEN Chunyang;LIU Jiang;YANG Xuehong;ZHENG Di(School of Safety Engineering,North China Institute of Science and Technology,Yanjiao 065201,China;Hebei Key Laboratory of Strategic Critical Mineral Resources,Yanjiao 065201,China;School of Mine Safety,North China Institute of Science and Technology,Yanjiao 065201,China)
出处
《华北科技学院学报》
2025年第3期1-11,共11页
Journal of North China Institute of Science and Technology
基金
国家自然科学基金资助项目(51804119)
河北省自然科学基金项目(E2021508008)
中国科协青年人才托举工程项目(YESS20210414)。
关键词
穿层巷道
循环加卸载
声发射
电镜扫描
分形维数
cross-layer roadway
cyclic loading-unloading
acoustic emission
scanning electron microscopy
fractal dimension
