Research On Fault Activation Mechanism And Monitoring Technology In Coal Seam Mining Process

The coal seam mining will cause the deformation and destruction of the roof,and also cause the activation of the fault.The depth,strength and scope of the roof are closely related to the safety of the coal mine.Therefore,monitoring the failure process of coal seam roof and developing fault activation research is an essential task for coal mine safety production.Based on the theories and methods of geology,mining,rock mechanics and hydrogeology,this thesis takes the Zibo Mining Group Xuchang Coal Mine as the background to study the development height of "two belts" and the mechanism of fault activation near the fault zone.This thesis first studies the failure mechanism of fault activation,expounds the failure theory of overlying rock and the law of electrical variation of overlying rock,and uses the FLAC3 D numerical simulation technology to simulate the roof failure of coal seam,analyses the deformation and failure and movement characteristics of the overburden,and obtains the depth of the failure of the coal seam roof,and then combines the electrical parameters of rock mass and the geological structure.The dynamic monitoring of the failure process of coal seam roof is carried out by the parallel network method,and compared with the numerical simulation results,combined with the actual observation of the roadway,the characteristics of the overlying rock failure are analyzed.Thesis work to achieve the following results:(1)the multi-electrode resistivity method can effectively monitor the geological conditions such as the height of the development of the crack zone of the roof,the depth of the failure of the floor and the process of the development of the fault activation and water diversion under the reasonable arrangement of the observation parameters.(2)The multi-electrode resistivity method is used to set electrodes in the roof and floor of the coal seam mining face.It can monitor the activation of fault caused by the coal mining face in real time.It has the characteristics of low cost and high efficiency.(3)The amplitude of fault activation is more obvious after the coal seam passes through the fault.Under the influence of mining,the depth,strength and range of fault zone are weakened with the increase of the distance from the bottom of the mining face.(4)There is a stress concentration in the front of the working face without the influence of the fault,which leads to the descent of the roof and the position of the mining face,the maximum stress is reached and the maximum decrease is reached.After the recovery,the stress release leads to the collapse of the roof,and the activation of the fault is changed when the roadway affected by the fault is recovered to the fault.The stress field distribution around the roadway and the roof near the fault show an upward trend.