Yongliang He, Liying Sun, Xuegang Xing
School of Engineering for Safety and Emergency Management, Taiyuan University of Science and Technology, Taiyuan 030024, China.
Intelligent Monitoring and Control of Coal Mine Dust Key Laboratory of Shanxi Province, Taiyuan University of Science and Technology, Taiyuan, Shanxi 030024, China.
ACS Omega. 2024 Sep 12;9(38):40110-40121. doi: 10.1021/acsomega.4c06087. eCollection 2024 Sep 24.
Coal damage accumulation and strength deterioration caused by mining-induced disturbances in deep mines are among the factors influencing the occurrence of dynamic disasters such as rock bursts. To study the mechanical deformation and failure characteristics of coal masses under both cyclic impact and confining pressure, SHPB experiments were performed to systematically analyze the behavior of coal samples under 1, 2, and 3 cycles at impact pressures of 0.25, 0.30, 0.35, 0.40, and 0.45 MPa. To study the influence of pressure and impact frequency on the dynamic mechanical failure of coal samples, a weakening effect model of coal samples under confining pressure was established, revealing the dynamic mechanical characteristics and failure mechanism of coal samples under different impact pressures and impact frequencies. The confining pressure SHPB results reveal that the number of cycles and impact pressure are inversely proportional to the peak stress and are proportional to the degree of weakening. The peak stress weakening coefficient of the coal samples under the different impact pressures ranged from 28.5 to 73.2%, and a linear weakening relationship with the number of cycles was obtained. The coal exhibited an end effect-controlled Y-shaped failure mode under both confining pressure and dynamic loading. This study provides an experimental reference for preventing the energy absorption and erosion of weak structures around rock bursts and improving the stability of supporting structures.
深部矿井开采扰动引起的煤体损伤累积和强度劣化是影响冲击地压等动力灾害发生的因素之一。为研究循环冲击和围压作用下煤体的力学变形及破坏特性，进行了分离式霍普金森压杆（SHPB）试验，系统分析了煤样在0.25、0.30、0.35、0.40和0.45MPa冲击压力下1、2和3个循环的行为。为研究压力和冲击频率对煤样动态力学破坏的影响，建立了围压作用下煤样的弱化效应模型，揭示了不同冲击压力和冲击频率下煤样的动态力学特性及破坏机理。围压SHPB试验结果表明，循环次数和冲击压力与峰值应力成反比，与弱化程度成正比。不同冲击压力下煤样的峰值应力弱化系数在28.5%至73.2%之间，并得到了与循环次数的线性弱化关系。煤在围压和动载作用下均呈现端部效应控制的Y形破坏模式。该研究为防止冲击地压周围薄弱结构的能量吸收和侵蚀以及提高支护结构稳定性提供了试验参考。
