冲击载荷作用下硬煤的动态力学特性研究
|
摘要
为研究硬煤在动载荷作用下的力学特性,采用分离式霍普金森压杆(SHPB)测试系统开展了径向自由和被动围压2种约束状态下不同冲击速度的硬煤试件冲击压缩试验,研究了硬煤的动态力学特性及其随应变率、约束状态的变化规律,分析了试件的破坏形态,并结合声波测试研究了被动围压时硬煤试件的损伤特性。研究结果表明:冲击速度、约束状态对动态抗压强度峰值和应变率的影响很大,径向自由时动态抗压强度峰值与应变率呈线性增长关系、被动围压时动态抗压强度峰值随应变率的增大而减小;动态抗压强度峰值随冲击速度的增大呈对数关系,随冲击速度的增大,且被动围压时动态抗压强度峰值增长更快;径向自由时,试件的破坏以劈裂破坏和压碎破坏为主,破碎形态和块度取决于冲击速度,被动围压下试件能够保持完整、仅表面和边缘出现裂纹;被动围压条件下,试件的损伤程度与冲击速度呈指数关系。
In order to study the mechanical properties of hard coal under dynamic load, the Split Hopkinson Pressure Bar(SHPB) test system is used to carry out the impact compression test of hard coal specimens with different impact speeds under radial and passive confining conditions. The dynamic mechanical properties of hard coal and its variation with strain rate and restraint state are studied. The failure modes of the specimens are analyzed, and the damage characteristics of specimens under passive confining pressure are studied through combined acoustic wave tests. The results have shown that the impact velocity and constraint state have a great influence on the peak value of dynamic compressive strength and strain rate. The radial compressive strength peak and the strain rate will increase linearly when radial direction is free, and the dynamic compressive strength peak will decrease with the increase of strain rate during passive confining pressure. The peak value of dynamic compressive strength is logarithmically related to the increase of impact velocity. With the increase of impact velocity, the peak value of dynamic compressive strength increases faster during passive confining pressure. When the radial direction is free, the failure of the test piece will be mainly caused by splitting and crushing damage. The fracture shape and the lumpiness depend on the impact speed. Under the passive confining pressure, the test piece can remain intact, and only the surface and the edge are cracked. Under the condition of passive confining pressure, the damage degree of the test piece is exponentially related to the impact speed.
In order to study the mechanical properties of hard coal under dynamic load, the Split Hopkinson Pressure Bar(SHPB) test system is used to carry out the impact compression test of hard coal specimens with different impact speeds under radial and passive confining conditions. The dynamic mechanical properties of hard coal and its variation with strain rate and restraint state are studied. The failure modes of the specimens are analyzed, and the damage characteristics of specimens under passive confining pressure are studied through combined acoustic wave tests. The results have shown that the impact velocity and constraint state have a great influence on the peak value of dynamic compressive strength and strain rate. The radial compressive strength peak and the strain rate will increase linearly when radial direction is free, and the dynamic compressive strength peak will decrease with the increase of strain rate during passive confining pressure. The peak value of dynamic compressive strength is logarithmically related to the increase of impact velocity. With the increase of impact velocity, the peak value of dynamic compressive strength increases faster during passive confining pressure. When the radial direction is free, the failure of the test piece will be mainly caused by splitting and crushing damage. The fracture shape and the lumpiness depend on the impact speed. Under the passive confining pressure, the test piece can remain intact, and only the surface and the edge are cracked. Under the condition of passive confining pressure, the damage degree of the test piece is exponentially related to the impact speed.
引文
[1]王家臣,王兆会,孔德中.硬煤工作面煤壁破坏与防治机理[J].煤炭学报,2015,40(10):2243-2250.WANG Jiachen,WANG Zhaohui,KONG Dezhong.Failure and prevention mechanism of coal wall in hard coal seam[J].Journal of China Coal Society,2015,40(10):2243-2250.
[2]李定启.深部硬煤掘进工作面煤与瓦斯突出机制探讨[J].岩土力学,2014,35(增刊1):1-7.LI Dingqi.Discussion on mechanism of coal and gas outbursts in face of hard coal roadway tunneling in deep coal seam[J].Rock and Soil Mechanics,2014,35(Sup 1):1-7.
[3]刘晓辉,张苑,刘建峰.不同应变率下煤岩冲击动力试验研究[J].煤炭学报,2012,37(9):1528-1534.LIU Xiaohui,ZHANG Yuan,LIU Jianfeng.Dynamic test study of coal rock under different strain rates[J].Journal of China Coal Society,2012,37(9):1528-1534.
[4]李明,茅献彪,曹丽丽,等.高应变率下煤力学特性试验研究[J].采矿与安全工程学报,2015,32(2):317-324.LI Ming,MAO Xianbiao,CAO Lili,et al.Experimental study on mechanical properties of coal under high strain rate[J].Journal of Mining&Safety Engineering,2015,32(2):317-324.
[5]高文蛟,单仁亮,苏永强.无烟煤单轴冲击动态强度理论[J].爆炸与冲击,2013,33(3):297-302.GAO Wenjiao,SHAN Renliang,SU Yongqiang.Theoretical research on dynamic strength of anthracite under uniaxial impact[J].Explosion and Shock Waves,2013,33(3):297-302.
[6]付玉凯,解北京,王启飞.煤的动态力学本构模型[J].煤炭学报,2013,38(10):1169-1774.FU Yukai,XIE Beijing,WANG Qifei.Dynamic mechanical constitutive model of the coal[J].Journal of China Coal Society,2013,38(10):1169-1774.
[7]穆朝民,宫能平.煤体在冲击荷载作用下的损伤机制[J].煤炭学报,2017,42(8):2011-2018.MU Chaomin,GONG Nengping.Damage mechanism of coal under impact loads[J].Journal of China Coal Society,2017,42(8):2011-2018.
[8]王登科,刘淑敏,魏建平,等.冲击载荷作用下煤的破坏特性试验研究[J].采矿与安全工程学报,2017,34(3):594-600.WANG Dengke,LIU Shumin,WEI Jianping,et al.The failure characteristics of coal under impact load in laboratory[J].Journal of Mining&Safety Engineering,2017,34(3):594-600.
[9]江红祥,杜长龙,刘送永.冲击速度对煤岩破碎能量和粒度分布的影响[J].煤炭学报,2013,38(4):604-609.JIANG Hongxiang,DU Changlong,LIU Songyong.The effects of impact velocity on energy and size distribution of rock crushing[J].Journal of China Coal Society,2013,38(4):604-609.
[10]张文清,石必明,穆朝民.冲击载荷作用下煤岩破碎与耗能规律实验研究[J].采矿与安全工程学报,2016,33(2):375-380.ZHANG Wenqing,SHI Biming,MU Chaomin.Experimental research on failure and energy dissipation law of coal under impact load[J].Journal of Mining&Safety Engineering,2016,33(2):375-380.
[11]刘瑜,周甲伟,杜长龙.煤块冲击破碎粒度分形特征[J].振动与冲击,2013,32(3):18-21,28.LIU Yu,ZHOU Jiawei,DU Changlong.Fractual character of impact crushing granularity of coal lumps[J].Journal of Vibration and Shock,2013,32(3):18-21,28.
[12]刘少虹,秦子晗,娄金福.一维动静加载下组合煤岩动态破坏特性的试验分析[J].岩石力学与工程学报,2014,33(10):2064-2075.LIU Shaohong,QIN Zihan,LOU Jinfu.Experimental study of dynamic failure characteristics of coal-rock compound under one-dimensional static and dynamic loads[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(10):2064-2075.
[13]李成武,王金贵,解北京,等.煤岩材料SHPB实验被动围压数值模拟研究[J].采矿与安全工程学报,2014,31(6):957-962.LI Chengwu,WANG Jingui,XIE Beijing,et al.Numerical analysis of split Hopkinson pressure bar test with passive confined pressure for coal[J].Journal of Mining&Safety Engineering,2014,31(6):957-962.
[14]王礼立,胡时胜,杨黎明,等.材料动力学[M].合肥:中国科学技术大学出版社,2017:179-180.
[15]许金余,吕晓聪,刘军忠,等.斜长角闪岩累积损伤特性的围压效应研究[J].土木工程学报,2012,45(1):115-120.XU Jinyu,LYU Xiaocong,LIU Junzhong,et al.Study of the confining pressure effect of amphibolites cumulative damage properties under cyclical impact loadings[J].China Civil Engineering Journal,2012,45(1):115-120.
[16]吕晓聪,许金余,葛洪海,等.围压对砂岩动态冲击力学性能的影响[J].岩石力学与工程学报,2010,29(1):193-201.LYU Xiaocong,XU Jinyu,GE Honghai,et al.Effects of confining pressure on mechanical behaviors of sandstone under dynamic impact loads[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(1):193-201.
[17]刘军忠,许金余,吕晓聪,等.主动围压下岩石的冲击力学性能试验研究[J].振动与冲击,2011,30(6):120-126.LIU Junzhong,XU Jinyu,LYU Xiaocong,et al.Experimental study on rock's mechanical capabilities under impact loading with confining pressure[J].Journal of Vibration and Shock,2011,30(6):120-126.
[18]胡英国,卢文波,陈明,等.岩体爆破近区临界损伤质点峰值震动速度的确定[J].爆炸与冲击,2015,35(4):547-554.HU Yingguo,LU Wenbo,CHEN Ming,et al.Determination of critical damage PPV near the blast hole of rock-mass[J].Explosion and Shock Waves,2015,35(4):547-554.
[2]李定启.深部硬煤掘进工作面煤与瓦斯突出机制探讨[J].岩土力学,2014,35(增刊1):1-7.LI Dingqi.Discussion on mechanism of coal and gas outbursts in face of hard coal roadway tunneling in deep coal seam[J].Rock and Soil Mechanics,2014,35(Sup 1):1-7.
[3]刘晓辉,张苑,刘建峰.不同应变率下煤岩冲击动力试验研究[J].煤炭学报,2012,37(9):1528-1534.LIU Xiaohui,ZHANG Yuan,LIU Jianfeng.Dynamic test study of coal rock under different strain rates[J].Journal of China Coal Society,2012,37(9):1528-1534.
[4]李明,茅献彪,曹丽丽,等.高应变率下煤力学特性试验研究[J].采矿与安全工程学报,2015,32(2):317-324.LI Ming,MAO Xianbiao,CAO Lili,et al.Experimental study on mechanical properties of coal under high strain rate[J].Journal of Mining&Safety Engineering,2015,32(2):317-324.
[5]高文蛟,单仁亮,苏永强.无烟煤单轴冲击动态强度理论[J].爆炸与冲击,2013,33(3):297-302.GAO Wenjiao,SHAN Renliang,SU Yongqiang.Theoretical research on dynamic strength of anthracite under uniaxial impact[J].Explosion and Shock Waves,2013,33(3):297-302.
[6]付玉凯,解北京,王启飞.煤的动态力学本构模型[J].煤炭学报,2013,38(10):1169-1774.FU Yukai,XIE Beijing,WANG Qifei.Dynamic mechanical constitutive model of the coal[J].Journal of China Coal Society,2013,38(10):1169-1774.
[7]穆朝民,宫能平.煤体在冲击荷载作用下的损伤机制[J].煤炭学报,2017,42(8):2011-2018.MU Chaomin,GONG Nengping.Damage mechanism of coal under impact loads[J].Journal of China Coal Society,2017,42(8):2011-2018.
[8]王登科,刘淑敏,魏建平,等.冲击载荷作用下煤的破坏特性试验研究[J].采矿与安全工程学报,2017,34(3):594-600.WANG Dengke,LIU Shumin,WEI Jianping,et al.The failure characteristics of coal under impact load in laboratory[J].Journal of Mining&Safety Engineering,2017,34(3):594-600.
[9]江红祥,杜长龙,刘送永.冲击速度对煤岩破碎能量和粒度分布的影响[J].煤炭学报,2013,38(4):604-609.JIANG Hongxiang,DU Changlong,LIU Songyong.The effects of impact velocity on energy and size distribution of rock crushing[J].Journal of China Coal Society,2013,38(4):604-609.
[10]张文清,石必明,穆朝民.冲击载荷作用下煤岩破碎与耗能规律实验研究[J].采矿与安全工程学报,2016,33(2):375-380.ZHANG Wenqing,SHI Biming,MU Chaomin.Experimental research on failure and energy dissipation law of coal under impact load[J].Journal of Mining&Safety Engineering,2016,33(2):375-380.
[11]刘瑜,周甲伟,杜长龙.煤块冲击破碎粒度分形特征[J].振动与冲击,2013,32(3):18-21,28.LIU Yu,ZHOU Jiawei,DU Changlong.Fractual character of impact crushing granularity of coal lumps[J].Journal of Vibration and Shock,2013,32(3):18-21,28.
[12]刘少虹,秦子晗,娄金福.一维动静加载下组合煤岩动态破坏特性的试验分析[J].岩石力学与工程学报,2014,33(10):2064-2075.LIU Shaohong,QIN Zihan,LOU Jinfu.Experimental study of dynamic failure characteristics of coal-rock compound under one-dimensional static and dynamic loads[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(10):2064-2075.
[13]李成武,王金贵,解北京,等.煤岩材料SHPB实验被动围压数值模拟研究[J].采矿与安全工程学报,2014,31(6):957-962.LI Chengwu,WANG Jingui,XIE Beijing,et al.Numerical analysis of split Hopkinson pressure bar test with passive confined pressure for coal[J].Journal of Mining&Safety Engineering,2014,31(6):957-962.
[14]王礼立,胡时胜,杨黎明,等.材料动力学[M].合肥:中国科学技术大学出版社,2017:179-180.
[15]许金余,吕晓聪,刘军忠,等.斜长角闪岩累积损伤特性的围压效应研究[J].土木工程学报,2012,45(1):115-120.XU Jinyu,LYU Xiaocong,LIU Junzhong,et al.Study of the confining pressure effect of amphibolites cumulative damage properties under cyclical impact loadings[J].China Civil Engineering Journal,2012,45(1):115-120.
[16]吕晓聪,许金余,葛洪海,等.围压对砂岩动态冲击力学性能的影响[J].岩石力学与工程学报,2010,29(1):193-201.LYU Xiaocong,XU Jinyu,GE Honghai,et al.Effects of confining pressure on mechanical behaviors of sandstone under dynamic impact loads[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(1):193-201.
[17]刘军忠,许金余,吕晓聪,等.主动围压下岩石的冲击力学性能试验研究[J].振动与冲击,2011,30(6):120-126.LIU Junzhong,XU Jinyu,LYU Xiaocong,et al.Experimental study on rock's mechanical capabilities under impact loading with confining pressure[J].Journal of Vibration and Shock,2011,30(6):120-126.
[18]胡英国,卢文波,陈明,等.岩体爆破近区临界损伤质点峰值震动速度的确定[J].爆炸与冲击,2015,35(4):547-554.HU Yingguo,LU Wenbo,CHEN Ming,et al.Determination of critical damage PPV near the blast hole of rock-mass[J].Explosion and Shock Waves,2015,35(4):547-554.