Surrounding rock failure characteristics and its control in the roadway influenced by multiple mining of close distance coal seams
Aiming at the stability control of surrounding rock in the roadway of the upper and lower mining face of the coal seam in close proximity of Longde Coal Mine.The roadway support forcing characteristics and coal pillar's stress evolving characteristics under the influence of multiple mining are studied using on-site observation and theoretical analysis.The re-sults show that the bolt/cable force of roadway undergoes 7 stages:the initial stable stage before the influence of mining,the advanced influential stage of single working face,the advanced influential stage of double working faces,the rapid rising stage of mining pressure relief zone,the slow rising stage of mining stress recovery zone,the secondary stable stage and the rising stage of mining disturbance.The evolution of the mining stress of coal pillar experiences five stages:the initial stable stage before the influence of mining,the slow rising stage of the advanced influence area of working face,the fast rising stage of the mining pressure relief area,the free evolution stage of the mined-out area compaction and the rising stage of mining disturbance.With the increase of the installation depth of the borehole stress meter,the stress of the coal pillar increased at first and then decreased.The shallow part of the coal pillar entered a plastic state at about 3 m,and the bearing capacity was reduced.Based on the above observation results,the support parameters of newly tunneling roadway were optimized to ensure the long-term stability of surrounding rock and reduce the support cost.The measured results show that the roadway surface displacement was within the allowable range of the project,and the crack development degree of the surrounding rock was low.
close distance coal seamsroadway surrounding rockanchor/cable tensioncoal pillar stresssupport optimization
万方数据
维普
