Instability Law And Control Of Surrounding Rock In Compound Roof Coal Roadway Under Multiple Dynamic Pressure Disturbances

The age of coal seam formation determines the universality of compound roof in coal roadway,the instability of its structure greatly increases the difficulty of support,especially the support of compound roof coal roadway under dynamic pressure disturbance is a difficult problem that puzzles the safe and efficient production of coal mine.This paper takes compound roof coal roadway under multiple dynamic pressure disturbance as the research object,a systematic and in-depth study on anchorage structure and surrounding rock instability is carried out by combining theoretical analysis,laboratory experiments and numerical simulation.The following main results have been achieved:?1?The basic mechanical properties of surrounding rock of gas control roadway in 22301 working face of typical compound roof coal roadway are determined by experiments.A new type of similar simulation material for cementing iron-crystalline sand was tested,It is applied to the physical model making of compound roof coal roadway in mining field for the first time.The main factors affecting the stability of surrounding rock of this roadway are compound roof,dynamic pressure disturbance and unreasonable supporting structure system.?2?The failure mechanism of compound roof is obtained by force analysis based on mechanical model of compound roof,by using FLAC^3D numerical simulation software,the deformation characteristics of surrounding rock of roadway under the influence factors of position,thickness and lateral pressure coefficient of soft rock stratum are obtained:coal roadway with compound roof prone to large deformation and separation phenomenon,the deflection of roadway roof and the range of plastic zone are positively correlated with the location and thickness of weak strata,With the increase of lateral pressure coefficient,the plastic zone of surrounding rock decreases first and then increases.?3?Through numerical simulation analysis,the anchorage structure and surrounding rock stability of gas control roadway in 22301 working face during the third mining stage are obtained:as the effect of dynamic pressure increases,The roadway is affected by the superposition of high in-situ stress,lateral abutment pressure and advanced abutment pressure,the deformation of surrounding rock,the range of plastic zone and the stress of anchorage structure increase continuously,the original supporting structure can not maintain the stability of surrounding rock of roadway.?4?Optimized and determined the"high-strength bolt+steel belt+strong anchor cable+metal mesh"combined support scheme for gas control roadway of 22301working face.The stability of surrounding rock under the control of new and old support schemes is compared by simulation analysis,it is applied to field industrial test,The results of rock pressure monitoring show that the deformation of surrounding rock of roadway is effectively controlled after optimization.?5?Based on the principle of fiber Bragg grating,a dynamic monitoring system of YGS127?A?coal mine roadway surrounding rock with fiber bragg grating is developed to monitoring the force of bolt,monitoring results show that the stress of integral support structure is more uniform,the performance of support bearing body has been better developed to ensure the stability of surrounding rock-support bearing structure,which proves that the support structure can effectively control the deformation of surrounding rock in gas control roadway of 22301 working face.