Research On Control Technology Of Surrounding Rocks In Withdrawal Channel Of Fully Mechanized Caving Face In Huangyuchuan Coal Mine

The 21604 fully mechanized top coal caving face in Huangyuchuan coal mine adopts the pre excavation double withdrawal channel,which is significantly affected by the mining dynamic pressure in the final mining stage,the mine pressure appears violently,the surrounding rock deformation and damage are serious,which affects the safe and smooth withdrawal of the equipment.The 21605 face and 21604 face are in the same panel area,the coal seam occurrence conditions and roof and floor lithology are similar,the roadway layout and the proposed surrounding rock control measures are the same.Therefore,it is necessary to optimize the surrounding rock control measures of the withdrawing passage of 21605 working face to ensure the smooth operation of the equipment withdrawing.First of all,in this paper,field measurement and numerical simulation method are used to study the strata behavior and stress distribution law of 21604 face in the final mining stage.It can be determined that the significant range of the influence of mining on the main withdrawal channel is 30m.After the main withdrawal channel is cut through,the field ground pressure in this range is violent,the surrounding rock of the main withdrawal channel is seriously deformed and damaged,the plastic area is large,and the stress concentration reaches the peak value.When optimizing the support of the main withdrawal channel,the dynamic pressure control within the advancing range of the working face should be strengthened;and the mine pressure in the middle area(50m-200m)of the main withdrawal channel is more serious than that at both ends;although there is mine pressure in the auxiliary withdrawal channel under the influence of mining,the surrounding rock is relatively stable and can be used normally.Secondly,based on the theoretical analysis of the deformation and failure characteristics of the roof covering rock and its control measures in the last mining stage of the working face,it can be seen that the periodic pressure should be avoided as much as possible after the working face is connected with the withdrawal channel,and the technical measures for stopping mining and allowing pressure are elaborated in detail.On this basis,the auxiliary mine pressure control measures such as mining height control and forced caving are put forward.Finally,through the theoretical analysis and research of the back channel support technology,and the relevant parameters of the main support form are calculated.The paper puts forward the optimization measures of surrounding rock control,such as strengthening the roof and roadway wall by Malisan grouting,improving the design anchoring force of anchor bolt in the main withdrawal channel,and strengthening the support along the return air chute near the main withdrawal channel.After the analysis of numerical simulation,the optimization measures of surrounding rock proposed for the 21605 working face are feasible.The field measurement also shows that after adopting the surrounding rock control optimization measures in 21605 working face,the subsidence of the roof in the main withdrawal channel,the shrinkage under the cribbing support,and the approach of the roadway side movement are significantly reduced compared with 21604 working face,and the deformation of the surrounding rock is well controlled.The field application has achieved remarkable results,ensuring the safe and efficient withdrawal of the equipment in 21605 working face.The research results of this paper can provide practical reference and reference for the control of the surrounding rock of the withdrawal channel in the follow-up other fully mechanized caving faces of Huangyuchuan coal mine,and provide experience guidance for the control of the surrounding rock of the withdrawal channel in other mines under similar circumstances.