Surrounding Rock Control Technology Of Artificial Pillar Collaborative Short-Wall Block Mining

The associated high-intensity longwall mining has resulted in numerous irregular blocks and residual coal pillars being left behind over the years of operation.Due to mining economics,surface environmental concerns,and other factors,the mining of residual coal areas(e.g.,‘under three’ pressed coal,slope pressed coal)has been limited.As a new development in mining,the short-wall block mining method has provided an effective technical solution for coal resource mining.Affected by the influence of previous longwall mining,short-wall block mining stope usually faced with complex stress environment,roof is not easy to form a stable structure,and remaining coal pillars have potential destabilization risk and other problems.Therefore,this thesis puts forward the surrounding rock control technology of artificial pillar collaborative short-wall block mining.The research method combines field investigation,theoretical analysis,laboratory experiment,numerical simulation and other means.The control principle of surrounding rock of artificial pillar collaborative short-wall block mining is analyzed.The main controlling factors of surrounding rock deformation of artificial pillar collaborative short-wall block mining are pointed out.Strong ductile cemented backfilling material was prepared.The instability mechanism and failure law of surrounding rock control technology of artificial pillar collaborative short-wall block mining are systematically studied.The engineering design of surrounding rock control technology of artificial pillar collaborative short-wall block mining is carried out.It aims to achieve the dual goals of safe coal mining and improving the recovery rate of resources.The main research results are as follows:(1)Based on the characteristics of short-wall block mining face layout,the surrounding rock control technology of artificial pillar collaborative short-wall block mining is proposed,and the deformation characteristics of surrounding rock control technology of artificial pillar collaborative short-wall block mining are analyzed,and the main controlling factors of surrounding rock deformation of artificial pillar collaborative short-wall block mining are obtained.(2)A variety of solid waste ratio tests are carried out and the workability and mechanical properties of cemented artificial pillar under different material ratio conditions are analyzed,and the optimal ratio of cemented artificial pillar filling material with reliable strength and good toughness is obtained.(3)The mechanical model of roof-surrounding rock-artificial pillar system in surrounding rock control technology of artificial pillar collaborative short-wall block mining is established,and the cusp catastrophe model of roof-surrounding rock-artificial pillar system is constructed based on the model.The instability mechanism of roof-surrounding rock-artificial pillar system is revealed.(4)The deformation and failure laws of surrounding rock under different width of artificial pillar,block length and material ratio are studied by numerical simulation.The optimal engineering design scheme satisfying the stability of artificial pillar and stope surrounding rock is obtained.Combined with the mining geological conditions of Serian No.1 mine,the engineering design of surrounding rock control technology of artificial pillar collaborative short-wall block mining is carried out.