Study On The Stability Control Technology Of Surrounding Rock In A Roadway Driving Along Goaf Forward To Mining Face In Limin Colliery

Gob-side entry driving Forward to Adjacent Mining Face (GEDFMF) not onlyhas advantages of traditional gob-side entry driving in aspects like recovery rate,stress environment and maintain conditions, but also can solve the urgent succeed ofmining and excavation effectively. The technology has been put into practicesuccessfully in many mining areas. The key stage of GEDFMF, the section of headingfor Adjacent minging face, will experience the whole dynamic pressure effect frombasic roof fracture to stabilization. Thus, it will experience3times additional stressdisturbance, which will bring about large surrounding rock deformation and difficultsupport.Based on the specific stress environment of GEDFMF in0913air-return entry,Limin Colliery, the thesis adopted comprehensive research methods, like theoreticalanalysis, numerical calculation and engineering test, to maintain the stability of thesurrounding rock, and acquired research conclusions in6aspects as below:(1) By analyzing the differences of stress loading on the entry forward toadjacent mining face, and the influence of fluctuating high stress generated byadjacent working face on GEDFMF, the study acquired the time-space effect in fourstages and analyzed the stability in each stage, got that the section of heading foradjacent minging face is the key to control the stability of surrounding rock inroadway driving along goaf.(2)Through analyzing stress distribution curve mode, peak point, stressconcentration coefficient and increasing rate in the key stage (the section of headingfor adjacent minging face), the study determined the influencing interval of additionalmining stress of adjacent working face on entry driving, and then determined thereasonable driving time.(3) By analyzing the relationship between different width of narrow coal pillar inkey stage, the section of heading for adjacent minging face, and stress distribution,displacement field and surround rock deformation, the reasonable width of narrowcoal pillar was determined as5m based on the theoretical calculation and designingprinciples for narrow coal pillar.(4) According to the stress disturbance characteristics of GEDFMF, the thesisdeemed that the key to maintain the whole stability of GEDFMF is to solidify the roofand narrow coal pillar rib, which means improving their bearing stability can maintain the stability of small structure of surrounding rock.(5) According to the different stress environment in different section ofGEDFMF, the thesis put forward dynamic staged control technology for the stabilityof surrounding rock. In allusion to the complex stress environment of GEDFMF, thethesis proposed united support technology, namely high strength high pre-stress bolt,signal hydraulic support and π-shape steel beam during the key stage.(6) The study determined the support parameters of each section of testing entryin Limin Coal Mine. The engineering test illustrated that the technology could controlthe surrounding rock effectively, and could meet the production requirements, whichcontributes to the significant economic and social benefits.