Study On Roof Structure Stability In Goaf Of Guojiawan Coal Mine

In Guojiawan a mined-out area of Shanxi Province as the research object,combining on-site investigation,a combination of theoretical analysis,numerical simulation tools and laboratory tests,etc.,from coal capitals board structural stability standpoint mined area for further stability the study.The establishment of a longwall coal pillar group-roof structure mechanical model,based on the renormalization group theory obtained pillar group-Roof critical instability probability,and the use of numerical simulation of goaf stability under the influence of multiple factors were studied.Research indicates:(1)Based on the law in force,the unknown constraint to support force F were analyzed by variation of the changes under study F other pillar supporting force,then study until the local coal Columns decay instability of coal pillar group-roof overall system stability of the law.(2)With local coal Columns reduce the load will be gradually transferred onto adjacent pillar,separated by a small pillar affected,if pillar adjacent continue crushing overload,the load will shift further outward diffusion,so that Effect of coal pillar groups-the overall stability of the roof structure.(3)Get the critical probability pillar group Goaf in the range 0.147?p*?<0.333.After the pillar buckling load is transferred to the extent of losses during pillar adjacent load transfer rate can be expressed,Pillar Group-roof unit critical failure probability p*With increasing load and decreasing the transfer rate.(4)In order to analyze the goaf safety and stability under the influence of dynamic disturbance,the goaf roof pillar mechanical model is bulit under the action of traffic loads and gravity stress taking goaf as research object based on the theory of elastic plate.(5)Pillar material mechanical parameters impact analysis,each pillar with the vertical displacement of the elastic modulus and internal friction and cohesion angle increases and decreases with the increase of Poisson's ratio increases.Under the same pillar,the elastic modulus and Poisson's ratio on the vertical displacement larger,less cohesion and internal friction angle of impact.(6)Size of impact analysis,the amount of vertical displacement of each pillar Pillar spacing increases with the increase,with the increase of coal pillar width and decreasing the amount of vertical displacement pillar influence significantly greater than the size factor under Pillar material mechanical parameters under the influence of the amount of displacement.