Study On The Support Technology Of Dismantling Channel Under The Condition Of Coal Pillar In The Overlying Goaf Of Huojitu Coal Mine

Chinese coal mining is mainly long wall comprehensive mining,for the moving and transferring of fully mechanized coal face,the dismantling channel is arranged in advance to fulfill the function of moving to the face,however,due to the influence of complex mining from the surrounding,the problem of mine pressure appearance and surrounding rock control and stability is particularly prominent.In this paper,the conditions of dismantling channel support engineering under the condition that the 22311 working face passes through the coal pillar of the overlying goaf are studied,through field investigation and analysis,numerical simulation analysis,mechanical analysis,field industrial test and other research methods,in this paper,the stability of the surrounding rock in the dismantling channel of the 22311 working face under the condition of goaf pillars in the overlying coal seam is analyzed,which provides technical reference for the stability of roadway support engineering under the condition that the withdrawal passage of 22311 working face passes through the coal pillar of the overlying goaf.The conclusions are as follows:（1）the influence of mining in the overlying goaf results in the obvious difference of surrounding rock stress environment between the bottom of coal pillar and the bottom of goaf;（2）the vertical stress environment in most positions under the floor of the goaf is reduced,but the local concentration is formed under the coal pillar;（3）the numerical equations of vertical stress distribution P_mzand lateral stress distribution P_mxof the surrounding rock in the dismantling channel are obtained by numerical fitting;（4）Based on the analysis of the mechanical theory by using theРуппенейтEquation,it is concluded that therefore,the back channel support control of 22311 working face should be based on the back channel support control roadway under the coal pillar,the support control roof and floor near the-50～75 m position under the coal pillar,and pay attention to the deformation effect of the surrounding rock within 75 m before and after the back channel located under the coal pillar;（5）this paper puts forward the combined support scheme of"bolt+metal mesh+anchor cable+shotcrete on the bottom plate"under the condition that the dismantling channel of 22311 working face passes through the coal pillar of the overlying goaf,and through the feedback of deformation monitoring effect of field industrial test,the combined support effect is better under and near the coal pillar of the overlying goaf,and it can meet the requirements of stable control and safe use of the dismantling channel.