摘要
采用损伤孔隙裂隙结构的方法可以提高煤体的渗透性。利用液氮冷加载实验,研究煤样孔隙裂隙结构损伤后的物理力学性质变化规律。通过卸载后煤样表面裂隙宽度、整体孔隙量的变化值,研究煤样结构损伤的物理性质,运用单轴抗压强度研究煤样结构损伤的力学性质,进而揭示液氮冷加载对煤样结构损伤的作用机理。结果表明:1)随着煤样围压的增加,煤样结构损伤程度逐渐加剧,12~13 MPa围压使煤样发生破碎;2)在注液氮条件下,冷加载加速了围压煤样结构的损伤,10~11 MPa围压下煤样发生破碎;3)煤样裂隙结构开裂方向与层理方向垂直,随着围压的增加,煤样单轴抗压强度逐渐降低,力学性能劣化。注液氮引起的温度应力可以加速煤体结构损伤,对煤体改性增透和预防冲击地压灾害提供了新的方法。
The permeability of coal body can be improved by damaging the pore and fracture structure.The experimental approach of liquid nitrogen cold loading has been applied to coal samples to investigate the changing law of physical and mechanical properties of coal samples after the damage in their pore and fracture structure.According to the varied values of surface crack fissure width and the overall volume change value of coal samples after unloading,physical properties of coal sample with structural damage have been studied and the uniaxial compressive strengths has been studied to evaluate the mechanical properties of coal samples structure damage.The mechanism action of liquid nitrogen cold loading on the coal sample structure damage have then been revealed.The results have shown that:1)With the increases of confining pressure of the coal sample,the damage degree of coal sample structure will gradually intensify,with 12-13 MPa confining pressure causing the coal sample fracture.2)Under the condition of liquid nitrogen injection,cold loading accelerates the confining coal structural damage of coal samples with confining pressure,with 10-11 MPa confining pressure causing the coal sample Break.3)The cracking direction of the coal sample crack structure is perpendicular to the bedding direction,and the uniaxial compressive strength of coal sample decreases gradually with the increase of confining pressure,and the mechanical properties deteriorates.The temperature stress caused by the liquid nitrogen injection can accelerate the structural damage of coal samples.The research provides a new method for the permeability enhancement via coal body modification and for the prevention of rock burst disaster.
作者
李和万
左建平
王来贵
苏荣华
周浩
LI Hewan;ZUO Jianping;WANG Laigui;SU Ronghua;ZHOU Hao(School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Department of Mechanics and Science Engineering,Liaoning Technical University,Fuxin,Liaoning 123000,China)
出处
《采矿与安全工程学报》
EI
CSCD
北大核心
2020年第4期804-811,共8页
Journal of Mining & Safety Engineering
基金
国家自然科学基金青年基金项目(51704142)
国家自然科学基金面上项目(51474121,51474120)
辽宁省博士科研启动基金计划项目(2019-BS-115)
关键词
冷加载
煤体结构
损伤
液氮
cold loading
coal body structure
damage
liquid nitrogen
