不同粗糙度与围压下断层黏滑失稳的数值模拟研究  

Numerical Simulation Study on Seismic Instability of Fault with Different Roughness and Confining Pressures

作　　者：崔鹏 李地元[2] 弓昊 方旭刚 罗平框 蒋京泰 肖磊 张发宇 CUI Peng;LI Diyuan;GONG Hao;FANG Xugang;LUO Pingkuang;JIANG Jingtai;XIAO Lei;ZHANG Fayu(Huize Mining Branch,Yunnan Chihong Zinc&Germanium Co.,Ltd.,Huize 654200,China;School of Resources and Safety Engineering,Central South University,Changsha 410083,China)

机构地区：[1]云南驰宏锌锗股份有限公司会泽矿业分公司,云南会泽654200 [2]中南大学资源与安全工程学院,湖南长沙410083

出　　处：《金属矿山》2024年第9期65-74,共10页Metal Mine

基　　金：国家自然科学基金项目(编号:52074349)。

摘　　要：断层断面粗糙度与围压大小对断层黏滑过程中的力学特性具有重要影响。以某深部矿山断层周边的白云岩为研究对象,通过建立精细化数值模型,开展围岩试件的双轴压缩数值模拟,分析围压大小与断面粗糙程度对断层矿震失稳的影响规律。研究结果表明:随着断层粗糙程度JRC值与围压增大,围岩试件的弹性模量与弹性极限增大,轴向峰值应力增大且与变量之间保持正相关关系,试件剪胀效果减弱,围岩试件发生黏滑事件的次数减少,平均应力降数值与黏滑周期增大,导致断层活化被抑制,且一旦断层发生失稳,释放的能量大震级高;围岩试件的微观破坏机制以剪切为主、拉伸为辅,宏观表现为拉剪混合破坏;法向力链的热点分布区域平行于加载方向,切向力链的热点分布区域与剪切裂隙的热点分布区域相对应;随着断层粗糙程度JRC值增大,断层黏滑后对周边围岩的影响范围呈现多区域局部集中化分布;由围岩试件颗粒峰值速度分布可知,随着围压增大,断层黏滑后对周边围岩的影响范围更广,且主要集中于上下加载端位置。The roughness of fault surface and biaxial confining pressure have important influence on the mechanical properties of the fault during stick-slip period.In this paper,in order to analyze the influence law of the biaxial confining pressure and the fault surface roughness on the fault-induced mining seismicity,the dolomite around a fault in a deep mine was selected as the research object and biaxial compression numerical simulation was carry out for the surrounding rock specimen by establishing a refined numerical model.The results show that with the increase of the fault surface roughness JRC value and the biaxial confining pressure,the elastic modulus and elastic limit of the surrounding rock specimen increase;the axial peak stress increases and maintains the positive relationship with the variables;the shear dilation effect of the specimen is weakened;the number of stick-slip events in the surrounding rock specimen decreases;the average stress drop value and the stick-slip period increase,leading to the inhibition of fault activation.Once the fault has slipped,the released energy is in a high seismic level.The microscopic damage mechanism of the surrounding rock specimen is dominated by shear and supplemented by tensile,and the macroscopic performance is a mixed mode of tensile-shear failure.Inside the surrounding rock specimen,the hot spot distribution area of the magnitude of tensile contact force is parallel to the loading direction,and the hot spot distribution area of the magnitude of shear contact force corresponds to the hot spot distribution area of the shear cracks.With the increase of the fault surface roughness JRC value,the influence range of the fault stick-slip on the surrounding rocks shows a multi-regional localized and concentrated distribution.From the particles peak velocity distribution of the surrounding rock specimen,with the increase of the biaxial confining pressure,the influence range of the fault stick-slip on the surrounding rock is wider,and mainly concentrated in the upper and lower

关 键 词：断层矿震 黏滑事件 断层断面粗糙度 围压 应力降 黏滑周期 

分 类 号：TD313[矿业工程—矿井建设]