临近断层特厚煤层分层开采冲击地压发生机制

为了研究临近断层分层开采的冲击地压发生机制,以老虎台矿特厚煤层开采为研究背景,采用地质动力区划方法、数值模拟和现场监测方法对井田的地质动力环境、临近断层开采的围岩应力分布规律和断层滑移特征及其与冲击地压的关系进行了研究。采用地质动力区划方法,将老虎台井田断裂构造划分为5级,通过地震和矿震分布情况,确定老虎台矿地质构造活跃,处于较高的应力环境;采用FLAC3D数值模拟和锚索应力监测方法,分析断层围岩应力演化规律和断层滑移规律,在断层和开采共同作用下工作面断层侧超前支承压力急剧升高。结果表明,地质动力环境为冲击地压的发生创造了外界环境条件,断层和采动的耦合作用是冲击地压诱发的主要原因。

Mechanism accounting for the rock-bursts in mining the thick coal seam near the fault zone

This paper is aimed at presenting the results of our analysis of the geological environment of the Laohutai coal mine,so as to grasp the surrounding rock stress distribution regularity of mining-causing faults,the fault slip characteristics and its relationship between the time intervals of the rockbursts by using the geological dynamic division method,numerical simulation and anchor cable stress monitoring method.In order to identify and grasp firmly the mechanism leading to the frequently occurring rock bursts near the fault,we have chosen the thick coal seam slicing mining of the said coal mine as the research project.While dividing the structural blocks of the mine by using the geological dynamic division method along with the navigation,interpretation and identification of the satellite photos in addition to the area survey of the seismic and tectonic activity,we have divided fracture structures into five levels.The aforementioned analysis of the distribution features of earthquake and rockburst situation has made us prove that the geological structure of the said mine remains in a status in situ being highly active and highly-stressed.We have also analyzed the surrounding rock stress evolution regularity and the fault slip-and-sliding regularity with a FLAC3D numerical simulation software and a cable stress monitoring method.In terms of the function of the fault,we have found that the advanced abutment pressure has been increased from 2 MPa to 4 MPa with the ahead disturbance effect scope being increased by 40 m.What is more,the ahead advanced abutment pressure remains at a higher level whereas its affecting scope has been found greater.Thus,the cable working resistance monitor indicates that the overlying strata turn to be activated after the busy mining operations,which also imply that the fault motion is also relatively active and the mining stress has been affected in a very wide range of the mining ahead-face,with two sets of faults being sustainably dislocated.It is also just because of the joint effects of the two factors,the fault would likely be activated as a result of the repeated mining operations while the ahead abutment pressures in the side of the fault area tends to grow significantly.From what is discussed above,it can be concluded that the author of this paper has identified and determined the actual mechanism of the rockburst mining thick coal seam near the fault,confirming the geological dynamic environment created due to the resulted rockburst,with its coupling effect of the fault,though mining should be taken as the main reason for it.