Research And Application Of Gob-Side Entry Retaining Technology With High-Water Packing In Yitian Coal Mine

Retained gob-side entry(RGE)technology has a series of significant advantages,such as improving the recovery rate of coal resources,reducing mining costs,alleviating the tension of mining replacement of mining and driving,and realizing Y-type ventilation.It is of far-reaching significance to promote the sustainable development of coal resources in China.However,serious deformation of RGE,the problem between the support of roadside backfilling body and extraction hinders the wide application of RGE in coal mines.Therefore,based on the RGE in 1101 high-grade general mining face of Yitian Coal Mine,this paper systematically studies the key problems of surrounding rock stability mechanism,parameters of roadside support and surrounding rock control technology of RGE by laboratory test,theoretical analysis,numerical simulation and engineering application.The research results have been successfully applied to Yitian Coal Mine with remarkable economic and social benefits.The main results are as follows:(1)To clarify the law of roof movement along RGE,discuss the bearing system of surrounding rock along RGE and the stress characteristics of coal wall,analyze the stage mechanism of roadside backfilling body,establish the mechanical model of surrounding rock structure,obtain the calculation formula of Support resistance of roadside backfilling body at different fracturepositions of roof,and verify that the compressive strength of roadside backfilling body meets the requirements.Based on the geological and mining condition of RGE at 1101 panel of Yitian Coal Mine,the calculation formula for the needed strength and width of roadside backfilling body are concluded,the width of roadside backfilling body is determined theoretically;(2)According to the plastic zone and roof subsidence of RGE,the reasonable width of roadside backfilling body is determined compared with different width of roadside backfilling body by using FLAC numerical simulation,the correctness of theoretical results is further verified;(3)To introduce the high-water quick-setting backfilling material,put forward the pre-stress bearing structure of roadside backfilling body,analyze its mechanism,design the roadside backfilling system and process,determine the key parameters of roadside backfilling of transport entry at 1101 panel of Yitian Coal Mine of body combined with theoretical analysis and numerical simulation,and give the support technical scheme of RGE.On-site roadway retaining situation,rock pressure observation and rock cores from boreholes obtained from entry show that RGE has achieved good results,which can be used as a reference for the popularization and application of REG in other mines with similar geological conditions.