断层带破碎岩体采动剪切变形与渗透性演化规律  

Mining-induced shear deformation and permeability evolution law of crushed rock mass in fault zone

作　　者：李樯 马丹 张吉雄[1,2] 刘勇[1] 侯文涛[1] LI Qiang;MA Dan;ZHANG Jixiong;LIU Yong;HOU Wentao(School of Mines,China University of Mining and Technology,Xuzhou 221116,China;MOE Key Laboratory of Deep Coal Resource Mining,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国矿业大学矿业工程学院,江苏徐州221116 [2]中国矿业大学深部煤炭资源开采教育部重点实验室,江苏徐州221116

出　　处：《煤田地质与勘探》2023年第8期150-160,共11页Coal Geology & Exploration

基　　金：国家自然科学基金项目(52122404,41977238)。

摘　　要：为探索采动影响下的断层活化突水机理,开展断层破碎岩体剪切变形与渗透性演化试验研究。基于流固耦合原理设计一套破碎岩体压剪渗流试验系统,实现破碎岩体剪切变形与渗流的耦合过程,开展多因素影响下的破碎岩体剪切-渗流耦合试验,获得连续剪切过程中颗粒级配和初始孔隙率对孔隙率和渗透性参量的影响规律。结果表明,连续剪切条件下,破碎岩体的渗透率和孔隙率变化过程大致相同,可分为3个阶段:缓慢增长阶段,破碎岩石颗粒由散乱状态向有序的组织结构调整;加速增长阶段,破碎岩石颗粒剪切膨胀;增速放缓阶段,破碎岩体颗粒的剪切变形在围压的约束下达到动态平衡。试样Talbot指数越小或初始孔隙率越大,渗透率和孔隙率敏感性越强,渗透率和孔隙率越大;非Darcy流β因子的演化规律与渗透率的演化规律相反。结合数值模拟发现,剪切作用下破碎岩体剪切带内岩石颗粒的运移是剪胀现象发生的主要原因,破碎岩体剪胀过程中颗粒的力链由随机分布向特定方向转化,表现为局部孔隙和孔喉的膨胀,是孔隙率和渗透率增加的主要原因。研究成果可为深部煤矿突水灾害机理揭示与灾害防治提供参考。To explore the mechanism of water inrush induced by fault activation under mining,experimental studies were conducted on the shear deformation and permeability evolution of crushed rock mass in fault zone.Specifically,a set of compression-shear-seepage test system for crushed rock mass was designed according to the principle of fluid-solid coupling,with the coupling process of shear deformation and seepage realized.On this basis,the shear-seepage coupling test was carried out for the crushed rock mass under the influence of multiple factors.Thus,the influence of particle size distribution and initial porosity of crushed rock mass on porosity and permeability parameters during continuous shearing process was obtained.According to the experimental results,the change process of permeability and porosity of the crushed rock is generally same under the continuous shear conditions,which can be divided into three stages:(1)the slowly increase stage,which reflects the process of crushed rock particles adjusting from scattered state to a certain organizational structure under confining pressure and shear stress;(2)the accelerated increase stage that reflects the shear swelling process of crushed rock under shear stress;and(3)the slowed increase stage,during which the crushed rock particles will finally reach dynamic equilibrium under the constraint of confining pressure.The sample with smaller Talbot index or larger initial porosity has higher permeability and porosity sensitivity,as well as greater permeability and porosity.However,the evolution law ofβfactor of non-Darcy flow is opposite to that of permeability.Through numerical simulation,it is found that the migration of rock particles within the shear zone of crushed rock mass under shear stress is the main cause of the shear swelling.The transformation of the force chain of particles from a random distribution to a specific direction during the shear swelling of crushed rock mass,which is manifested in the swelling of local pores and pore throats,is the main reason

关 键 词：断层突水 破碎岩体 剪切-渗流耦合 渗透特性 离散元模拟 

分 类 号：TD315[矿业工程—矿井建设]