Study On The Fracture Mechanism And Stability Control Of Surrounding Rock In Gob-side Entry Driving

This article takes 22117 return air roadway of Lu'an Coal Industry of Lu'an Group as research object,through in-depth field investigation and real-time microseismic monitoring,theoretical analysis and numerical simulation method for 22117 along goaf roadway surrounding rock broken characteristics,the plastic zone development situation,such as coal pillar and get the reasonable width of coal pillar and reasonable supporting scheme design,and verified by field of surrounding rock deformation monitoring research.The main conclusions of this paper are as follows:(1)The deformation of the surrounding rock of the roadway and the stress of the bolt have a good synchronization.The stability of the surrounding rock of the roadway can be judged in time by the force of the bolt and timely supplementary support measures can be taken to prevent the further deformation of the roadway;The larger or larger range of change fully indicates that the side of the coal pillar is more stressed under the action of the overburden;the closer it is to the working face,the more obvious the disturbance of the roadway.The advance support range must be observed and reasonably carried out in time Supplementary support.(2)Through calculation,it can be known that when the sum of the horizontal stress peak distance from the coal pillar to the side surface of the coal pillar and the horizontal distance from the ultimate strength in the coal pillar to the side surface of the coal pillar goaf is less than the width of the coal pillar,the calculated agreement The actual stress state of the coal pillar at the present stage;when the sum of the horizontal distance from the peak value of the stress in the coal pillar to the side surface of the coal pillar and the horizontal distance from the ultimate strength in the coal pillar to the side surface of the coal pillar is greater than the width of the coal pillar,Indicating that the coal pillars are all in the state of plastic failure.At this time,it is necessary to further assume the sum of the horizontal distance between the peak value of the stress in the coal pillar and the side surface of the roadway of the coal pillar and the horizontal distance from the ultimate strength in the coal pillar to the side surface of the goaf of the coal pillar When it is equal to the width of the coal pillar,continue to solve the stress state of the coal pillar at the same time.(3)The law of tunneling on the roof is a transition process gradually developed from the tunnel roof-coal pillar and roof-coal body roof(including the coal body below it).The range of the tunnel roof directly affected by tunneling is within 32.6m from the heading of the tunnel;The driving dynamic disturbance has a hysteresis effect on the microseism of the fracture of the roof of the rear coal pillar,and the affected range is about 93.3m behind the head.(4)Based on the on-site microseismic and electromagnetic radiation monitoring and borehole peeping,the microseismic and electromagnetic radiation coupling phenomena of the coal seam and direct roof on the coal pillar side and the influence range of the surrounding rock loosening ring under the influence of driving are analyzed,and the coal seam and direct roof on the coal pillar side are obtained Coupling phenomenon of microseismic and electromagnetic radiation is stronger than that of coal.The influence range of the surrounding rock loosening circle is very large,and the lower gang is relatively small.The damage range of the surrounding rock is consistent,and the effect of the upper anchor cable support is poor.Therefore,the anchor cable support parameters need to be optimized,and the anchor cable support still needs to be added at the lower edge.(5)The development of plastic zones with different coal pillar widths and different coal pillar widths under the same coal pillar width and the same buried depth are analyzed through numerical simulation.Development law of coal pillar plastic zone and under the same burial depth,with the increase of coal pillar width,the development law of coal pillar side plastic zone;considering the dynamic disturbance effect of the overlying hard rock layer,the average buried depth is about 530 m The width of the coal pillars along the empty tunnel in the face-down groove is 15 m.However,according to the burial depth of the roadway,when the local burial depth is greater than 530 m,on the foundation of the roadway upper and lower anchor bolts,the anchor cable located at the upper roof should be arranged.(6)To effectively control the deformation of surrounding rock of 22117 on the return air along the trough,according to research results,the supporting plan for fine-tuning,will be the most help on an anchor cable length adjustment of 6.3 m(anchorage length and the anchor cable),the anchor cable and the horizontal Angle of 30 ° construction,and will depend on the help of a cable to roof and vertical Angle of 30 ° construction,the present help coal body also is broken,the support and help to help.Through the actual monitoring results,it can be seen that the supporting effect is better after fine-tuning,and it can also provide reference for the same mining area 22122 backwind driving roadway.