Mechanical properties and failure behavior of rock with different flaw inclinations under coupled static and dynamic loads  

动静组合加载下含不同倾角裂隙岩石的力学特性与破坏规律

作　　者：XIAO Peng LI Di-yuan ZHAO Guo-yan ZHU Quan-qi LIU Huan-xin ZHANG Chun-shun 肖鹏;李地元;赵国彦;朱泉企;刘焕新;张春顺(School of Resources and Safety Engineering,Central South University,Changsha 410083,China;Deep Mining Laboratory of Shandong Gold Group,Laizhou 261442,China;Department of Civil Engineering,Monash University,Clayton,VIC 3800,Australia)

机构地区：[1]School of Resources and Safety Engineering,Central South University,Changsha 410083,China [2]Deep Mining Laboratory of Shandong Gold Group,Laizhou 261442,China [3]Department of Civil Engineering,Monash University,Clayton,VIC 3800,Australia

出　　处：《Journal of Central South University》2020年第10期2945-2958,共14页中南大学学报（英文版）

基　　金：Project(2019JJ20028)supported by the Outstanding Youth Science Foundations of Hunan Province of China;Project(51774321)supported by the National Natural Science Foundation of China;Project(2018YFC0604606)supported by the State Key Research Development Program of China。

摘　　要：The deep fissured rock mass is affected by coupled effects of initial ground stress and external dynamic disturbance.In order to study the effect of internal flaw on pre-stressed rock mechanical responses and failure behavior under impact loading,intact granite specimens and specimens with different flaw inclinations are tested by a modified split Hopkinson pressure bar(SHPB)and digital image correlation(DIC)method.The results show that peak strain and dynamic strength of intact specimens and specimens with different flaw angles(α)decrease with the increase of axial static pressure.The 90°flaw has weak reduction effect on peak strain,dynamic strength and combined strength,while 45°and 0°flaws have remarkable reduction effect.Specimens with 90°flaw are suffered combined shear and tensile failure under middle and low axial static pre-stresses,and suffered shear failure under high axial static pre-stresses.Specimens with 45°and 0°flaws are suffered oblique shear failure caused by pre-existing flaw under different axial static pre-stresses.Besides,based on digital image correlation method,it is found that micro-cracks before formation of macro fractures(include shear and tensile fractures)belong to tensile cracks.Tensile and shear strain localizations at pre-existing flaw tip for specimen with 45°and 0°flaws are produced much earlier than that at other positions.深部裂隙岩体开挖受初始地应力和外界动力扰动的共同作用。本文基于改进的霍普金森压杆和数字图像相关技术,对完整和含不同裂隙倾角的花岗岩进行预静载下的冲击试验,研究了动静组合加载下预制裂隙对岩石动态力学响应和破坏特性的影响规律。结果表明,完整试样和含不同裂隙倾角试样的峰值应变和动态强度随着轴向静压的增加而减小,加载方向90°的裂隙对峰值应变、动态强度和组合强度只有较弱的降低程度,而45°和0°裂隙则有明显的降低作用。含90°裂隙试样在中低轴向静压下发生剪切-拉伸复合破坏,在高轴向静压下发生剪切破坏。含45°和0°裂隙试样在不同的轴向静压下由于预制裂隙的影响均发生宏观剪切破坏。基于数字图像相关技术发现,在宏观裂纹(包括剪切和拉伸裂纹)形成前的微裂纹均属于拉伸裂纹,含45°和0°裂隙试样,在预制裂隙尖端要远早于其他位置产生的拉应变和剪应变集中。

关 键 词：split Hopkinson pressure bar(SHPB)system digital image correlation(DIC) coupled static and dynamic loads FLAW crack propagation 

分 类 号：TD315[矿业工程—矿井建设]