摘要
以板裂为表现形式的岩石脆性破坏行为是深埋硬岩岩体开挖卸荷造成的典型围岩破坏现象。在简要比较4种硬岩脆性破坏数值模拟方法的基础上,基于损伤启裂-板裂界限(Damage initiation and spalling limit,DISL)模型,借助FLAC^3D开展硬岩矿柱原位压缩及单轴压缩数值模拟,探讨DISL方法的适用性并进一步探究硬岩矿柱的脆性破坏过程及其特征。结果表明:原位压缩模拟中,当卸荷总时步大于某一临界数值时,矿柱两侧发生V形破坏,进而矿柱整体形成沙漏状;不同均质度下屈服破坏单元主要分布在V形破坏区内及周围,其分布范围受低围压区及张拉区范围的控制;V形剪切带主要以拉剪破坏为主,剪切带内部靠近矿柱边壁一侧,伴有张拉破坏单元;单轴压缩模拟中,峰后阶段矿柱两侧仍然产生V形破坏,并且张拉裂隙的形成范围受剪切带控制。
Brittle failure with slabbing and spalling as a dominant failure mode of surrounding rock is a typical failure phenomenon in deep hard rock masses due to excavation activity.On the basis of brief introduction and comparison of four different approaches for modelling failure of brittle hard rock masses,the numerical tests of in-situ compression and uniaxial compression of hard rock pillars were carried out by means of FLAC^3D based on the DISL method.The applicability of the DISL method was discussed and the brittle failure processes and characteristics of hard rock pillars were further explored.The results show that,in the in-situ compressive simulation,when the total unloading step is greater than a critical value,V-shaped failure occurs on both sides of the pillar,and the pillar forms an hourglass shape as a whole.Under different homogeneity indices,the yield elements are mainly distributed in and around V-shaped failure area and their distribution range is controlled by low confining pressure zone and tension zone.The V-shaped shear band is dominated by tension-shear failure and accompanied by tension failure elements in the inner part close to the pillar side wall.In the uniaxial compressive simulation,V-shaped failure still occurs on both sides of pillar in post-peak stage and the range of tension fracture is limited by shear band.
作者
刘建
赵国彦
胡静云
LIU Jian;ZHAO Guo-yan;HU Jing-yun(State Key Laboratory of Safety Technology of Metal Mines,Changsha Institute of Mining Research Co.,Ltd.,Changsha 410012,China;School of Resources and Safety Engineering,Central South University,Changsha 410083,China)
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2020年第3期684-697,共14页
The Chinese Journal of Nonferrous Metals
基金
国家重点研发计划资助项目(2016YFC0600702)。
关键词
硬岩矿柱
脆性破坏
数值模拟
DISL方法
破坏模式
强度特征
hard rock pillars
brittle failure
numerical simulation
DISL method
failure modes
strength characteristics
