高应力超大采空区围岩破裂机理研究  

Study on the Mechanism of Surrounding Rock Fracture at Large-size Goafs Under High Stress

作　　者：邓鹏宏[1] 崔瑞瑞[2] 刘建坡[2] 李元辉[2] 

机构地区：[1]鞍钢集团矿业公司,辽宁鞍山114004 [2]深部金属矿山安全开采教育部重点实验室,辽宁沈阳110004

出　　处：《金属矿山》2016年第7期84-89,共6页Metal Mine

基　　金：国家自然科学基金项目(编号:11232014;51109035);中央高校基本科研业务费专项(编号:N120701001;N120801002)

摘　　要：针对红透山铜矿岩爆等地压灾害频发现状,采用声发射与多点位移计联合监测技术,对27采场4分层边墙和顶板的岩体破裂及变形进行长期监测。通过位移与AE事件数的不同分时累计曲线比较发现:1硬脆性岩体在强卸荷后,其释放的变形很小,而且变形的波动总是先于AE事件。根据岩体变形破坏能量释放机制,围岩变形释放的应变能决定了岩体耗散能,而耗散能是导致岩体破裂的直接原因,所以,围岩变形是微破裂产生的先决条件。2岩体微破裂的开裂扩展改变了岩体的内部结构,在应力场的二次调整过程中,裂隙不断发育,直至产生稳定的岩体构造。为避免硬脆性岩体在高应力强卸荷条件下出现片帮、岩爆等剧烈破坏,建议通过增加卸荷瞬时释放变形的方式,加强岩体应变能的释放,从而减少耗散能;同时在爆破开挖后及时支护阻止岩体内部构造的劣化。另外在岩爆多发地段,增加布设高精度位移监测设备,通过卸荷后围岩变形的突变,对高应力条件下的地质灾害进行预测预报。Acoustic emission（ AE） events and multiple-point borehole extensometer were employed in the long term monitoring on rock mass deformation and fractures of sidewall and roof at the 4 sub-level 27 stope of Hongtoushan Copper Mine,where highly frequent ground pressure disasters occur,such as rock burst. Two observations could be derived from the deformation data comparison and different time cumulative curve of AE events： 1Initial deformation is very small after a strong unloading in hard brittle rock mass,and AE events lags behind the deformation occurrence. Release of strain energy in the surrounding rock affects dissipated energy of rock mass in terms of the energy release mechanism of deformation and fracture. The dissipated energy is primary factor to result in rock mass destruction,so the deformation of surrounding rock is precondition to produce the micro fracture. 2The internal structure of the rock mass has been changed due to the propagation of micro crack. In the secondary adjustment process of the stress field,fractures keep growing until generating a stable rock mass structure. Therefore,to avoid from spalling and rock burst in the hard brittle rock under high stress,an approach of increasing deformation in transient deformation of surrounding rock is suggested,which leads to improve the release strain energy of surrounding rock and hence reduce dissipated energy; Meanwhile,degradation on the internal structure of the rock mass can be prevented through setting up support system timely after excavation. Furthermore,in the field where rock burst frequently occurs,more displacement monitor equipments is suggested to lay out. Geological disasters under high stress could be forecasted by means of monitoring the sudden deformation of the surrounding rock after unloading.

关 键 词：岩石力学 高应力 强卸荷 声发射 多点位移计 

分 类 号：TU45[建筑科学—岩土工程]