上下盘开采影响下断层滑移失稳力学机制  

Mechanism of fault activation when mining on hanging-wall and foot-wall

作　　者：韩科明[1,2] 于秋鸽 张华兴[1,2] 李凤明[1] HAN Keming;YU Qiuge;ZHANG Huaxing;LI Fengming(Coal Mining and Design Branch,China Coal Research Institute,Beijing 100013,China;Coal Mining and Design Department,Tiandi Science and Technology Co.,Ltd.,Beijing 100013,China)

机构地区：[1]煤炭科学研究总院开采研究分院,北京100013 [2]天地科技股份有限公司开采设计事业部,北京100013

出　　处：《煤炭学报》2020年第4期1327-1335,共9页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(51874177,51604151);天地科技开采设计事业部青年基金资助项目(KJ-2018-TDKCZL-10)。

摘　　要：当工作面上覆岩层中含有断层时,地表下沉规律与不含断层时具有显著差别。为了研究上下盘开采断层滑移失稳力学机理,基于关键层理论建立了上下盘开采断层活化力学模型,推导了断层滑移失稳的判据,并结合数值模拟和相似模拟对上下盘开采断层活化难易程度进行了分析。研究结果表明:①相对于上盘开采,下盘开采断层保持稳定除了满足断层带岩体在断层面不发生滑移外还需满足断层面不产生离层,下盘开采断层保持稳定条件更加苛刻,下盘开采断层更容易活化;②对于上盘开采,随着工作面推进,浅部断层带岩体正应力逐渐减小,剪应力逐渐增大,深部断层带岩体剪应力和正应力都逐渐增大,说明断层露头处断层带岩体已经处于活化状态,断层带岩体产生裂隙,应力逐渐松弛,而深部断层带岩体正在为活化蓄能,浅部断层带岩体超前深部断层带岩体发生活化;③对于下盘开采,随着工作面推进,浅部断层带岩体剪应力和正应力逐渐增加,深部断层带岩体剪应力与正应力逐渐减小,工作面推进长度较小时,断层即活化;④工作面推进过程中,下盘开采断层带岩体剪应力与正应力的比值为上盘开采的3~5倍;⑤上盘开采断层活化时仅在断层露头处地表产生轻微裂隙,未形成明显台阶,下盘开采断层活化将在断层露头处产生明显台阶下沉。When fault exists in overburden strata,the earth-surface subsidence laws would be greatly different from the laws without faults.To study the mechanism of fault activation when mining on hanging-wall and foot-wall,the fault activation mechanical criterions were built.At the same time,the activation difficulty of mining on hanging-wall and foot-wall was analyzed by numerical simulation and analogue modeling.The results showed that the stability condition of footwall mining is more severe and fault can be activated more easily when mining on footwall.This is because the stability needs not only to meet the requirement that the fault zone rock mass does not slip at the fault plane,but also meet the requirement that the fault plane does not produce separation.For hanging-wall mining,with the advance of the working face,the normal stress of the rock mass in the shallow fault zone gradually decreases and the shear stress gradually increases,while both the shear stress and normal stress of the rock mass in the deep fault zone gradually increases,and the rock mass in the shallow fault zone is activated ahead of the rock mass in the deep fault zone.In the advance of working face,the ratio of shear stress to normal stress of rock mass in footwall mining is 3-5 times of that in hanging-wall mining.Fault is activated when mining on footwall,only slight cracks occur on the surface of fault outcrop,and no obvious steps are formed.However,fault outcrop will produce obvious steps sinking when mining on foot-wall.

关 键 词：开采沉陷 上下盘开采 断层活化 关键层理论 台阶下沉 

分 类 号：TD327[矿业工程—矿井建设]