束状炮孔爆破倾斜张开节理的动态断裂特性研究
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摘要
采用动态焦散线实验和ABAQUS数值模拟,对束状炮孔柱部区域和端部区域节理处裂纹的动态断裂特性进行了研究。结果表明,在炮孔柱部区域,初始爆炸应力波在张开节理处产生透射波与绕射波并与其相互叠加,节理端部产生拉剪应力集中形成翼裂纹,垂直于节理面起裂扩展。且节理近端翼裂纹扩展速度、扩展长度和裂纹尖端应力强度因子较节理远端处翼裂纹的相应值大。而次生裂纹是爆炸应力波在试件边界处产生的反射拉伸波与倾斜张开节理相互作用起裂的,并沿水平方向扩展。远端次生裂纹的起裂韧度约为翼裂纹的0.5倍,且由于反射波较弱,次生裂纹的扩展长度远小于翼裂纹。炮孔端部区域翼裂纹和次生裂纹是在倾斜张开节理处的反射拉伸波和绕射波与倾斜张开节理的相互作用下先后起裂的,翼裂纹偏向炮孔方向起裂,并向相反方向扩展,而次生裂纹近似沿着爆炸应力波的传播方向扩展。
The dynamic caustic method and ABAQUS numerical simulation were used to study the fracture mechanics characteristics of oblique open-joints in the column area and at the end region under bunch-hole explosion in oblique open-joints medium. The transmitted wave and diffracted wave generated by the initial explosion stress wave in the oblique open joints are superimposed on the initial explosion stress wave and the wing crack in the column area of the borehole propagates perpendicularly to the oblique open-joints surface due to the tensile-shear stress. Compared with the wing crack at the near-end of oblique open-joints, the propagation speed, crack length and stress intensity factor of the wing crack at the far-end of oblique open-joints are bigger. The reflected tensile wave generated by the explosion stress wave at the boundary of the specimen and the oblique open-joints interact with each other so as to induce the happening of secondary crack, which initiates and propagates similarly along the horizontal direction due to the tensile stress. The initial toughness of the secondary cracks at the far-end of oblique open-joints is about 0.5 times that of the wing crack. The secondary crack length is shorter than the wing crack because the intensity of the reflected wave is weaker. The wing crack and secondary crack at the end area of borehole occur due to the interaction of the oblique open-joints with the reflected tensile wave and diffracted wave in the oblique open-joints. The wing crack tends to initiate in the borehole direction, and propagates in the opposite direction, while the secondary crack initiates and propagates gradually along the direction of explosion stress waves.
The dynamic caustic method and ABAQUS numerical simulation were used to study the fracture mechanics characteristics of oblique open-joints in the column area and at the end region under bunch-hole explosion in oblique open-joints medium. The transmitted wave and diffracted wave generated by the initial explosion stress wave in the oblique open joints are superimposed on the initial explosion stress wave and the wing crack in the column area of the borehole propagates perpendicularly to the oblique open-joints surface due to the tensile-shear stress. Compared with the wing crack at the near-end of oblique open-joints, the propagation speed, crack length and stress intensity factor of the wing crack at the far-end of oblique open-joints are bigger. The reflected tensile wave generated by the explosion stress wave at the boundary of the specimen and the oblique open-joints interact with each other so as to induce the happening of secondary crack, which initiates and propagates similarly along the horizontal direction due to the tensile stress. The initial toughness of the secondary cracks at the far-end of oblique open-joints is about 0.5 times that of the wing crack. The secondary crack length is shorter than the wing crack because the intensity of the reflected wave is weaker. The wing crack and secondary crack at the end area of borehole occur due to the interaction of the oblique open-joints with the reflected tensile wave and diffracted wave in the oblique open-joints. The wing crack tends to initiate in the borehole direction, and propagates in the opposite direction, while the secondary crack initiates and propagates gradually along the direction of explosion stress waves.
引文
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[2]ADHIKARI G R,GUPTA R N.Influence of natural blocks on rock fragmentation by blasting[J].International Journal of Mining&Geological Engineering,1989,7(4):333-340.
[3]LARSON W C,PUGLIESE J M.Effects of jointing and bedding separation on limestone breakage at a reduced scale[R].Bureau of Mines,Twin Cities,Minn.(USA).[S.l]:Twin Cities Mining Research Center,1974.
[4]刘婷婷,李新平,李海波,等.应力波在充填节理岩体中传播规律的数值研究[J].岩石力学与工程学报,2016,35(增刊2):3552-3560.LIU Tingting,LI Xinping,LI Haibo,et al.Numerical study on stress wave propagation across filled joints[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(Sup 2):3552-3560.
[5]孙冰,郭闪闪,曾晟,等.应力波在层状节理岩体中的透反射与衰减规律[J].防灾减灾工程学报,2015,35(6):828-832.SUN Bing,GUO Shanshan,ZENG Sheng,et al.Transmission and reflection and the attenuation law of stress wave in layered joint rock mass[J].Journal of Disaster Prevention and Mitigation Engineering,2015,35(6):828-832.
[6]饶宇,赵根,吴新霞,等.应力波入射黏弹性节理的传播特性研究[J].岩土工程学报,2016,38(12):2237-2245.RAO Yu,ZHAO Gen,WU Xinxia,et al.Propagation characteristics of stress waves across viscoelastic joints[J].Chinese Journal of Geotechnical Engineering,2016,38(12):2237-2245.
[7]ZHU Z,MOHANTY B,XIE H.Numerical investigation of blasting-induced crack initiation and propagation in rocks[J].International Journal of Rock Mechanics&Mining Sciences,2007,44(3):412-424.
[8]ZHU Z.Numerical prediction of crater blasting and bench blasting[J].International Journal of Rock Mechanics&Mining Sciences,2009,46(6):1088-1096.
[9]李传明,刘万荣.节理岩体巷道围岩稳定性的颗粒离散元分析[J].中国安全科学学报,2017,27(4):133-138.LI Chuanming,LIU Wanrong.Particle discrete element method based analysis of stability of roadway surrounding joint rock mass[J].China Safety Science Journal,2017,27(4):133-138.
[10]宋林.节理岩体中应力波传播的动力特性研究[D].西安:西安建筑科技大学,2012.
[11]岳中文,郭洋,王煦,等.起爆时差对孔间裂纹扩展影响的动焦散实验研究[J].岩石力学与工程学报,2015,34(11):2293-2300.YUE Zhongwen,GUO Yang,WANG Xu,etal.Dynamic caustics of influence of delayed initiation on crack propagation between boreholes[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(11):2293-2300.
[12]郭东明,闫鹏洋,薛磊,等.动静载荷下巷道围岩裂纹扩展规律的试验研究[J].矿业科学学报,2016,1(2):146-154.GUO Dongming,YAN Pengyang,XUE Lei,et al.The experimental research on the propagation laws of cracks in roadway surrounding rock subjected to static-dynamic load[J].Journal of Mining Science and Technology,2016,1(2):146-154.
[13]宋俊生,王雁冰,高祥涛,等.定向断裂控制爆破机理及应用[J].矿业科学学报,2016,1(1):16-28.SONG Junsheng,WANG Yanbing,GAO Xiangtao,et al.The mechanism of directional fracture controlled blasting and its application[J].Journal of Ming Science and Technology,2016,1(1):16-28.
[14]郭东明,刘康,罗浪,等.爆炸载荷下邻近硐室迎爆侧原先裂纹扩展机理研究[J].矿业科学学报,2017,2(4):348-356.GUO Dongming,LIU Kang,LUO Lang,et al.Growth mechanism of original crack facing the blasting side of adjacent tunnel under the blasting load[J].Journal of Mining Science and Technology,2017,2(4):348-356.
[15]CHONG K P,KURUPPU M D.New specimen for fracture toughness determination for rock and other materials[J].International Journal of Fracture,1984,26(2):59-62.
[16]曾庆轩,简国祚,李兵,等.叠氮化铜JWL状态方程参数拟合[J].火工品,2014(6):28-31.ZENG Qingxuan,JIAN Guozuo,LI Bing,et al.The fitted parameters of JWL equation of state for copper azide[J].Initiators&Pyrotechnics,2014(6):28-31.
[17]岳中文,郭洋,许鹏,等.定向断裂控制爆破爆生裂纹扩展机理的实验研究[J].工程力学,2016,33(2):50-58.YUE Zhongwen,GUO Yang,XU Peng,et al.Experimental study on the mechanism of blast-induced crack propagation under directional fracture controlled blasting[J].Engineering Mechanics,2016,33(2):50-58.
[18]邓志勇,张志毅,王中黔.条形药包端部爆炸应力场的动光弹试验研究[J].爆炸与冲击,1996(1):86-90.DENG Zhiyong,ZHANG Zhiyi,WANG Zhongqian.Dynamic photo-elastic studies of explosive stress field at the end of a bunch-hole[J].Explosion and Shock Waves,1996(1):86-90.
[19]邓志勇,张志毅,王中黔.条形药包爆炸应力场试验研究[J].工程爆破,1995(2):31-34.DENG Zhiyong,ZHANG Zhiyi,WANG Zhongqian.Experimental study on stress field of explosion of bunch-hole[J].Engineering Blasting,1995(2):31-34.