Supporting Technology Research Of Roadway In Ultra-close Multiple-seams Mining

For ultra-Close multiple-seams mining,due to the minimum of distance between the coal seam,the roof below has been damaged before mining,leading a difficulties during coal seam mining maintenance,its control principle and supporting scheme of reasonable is still a problem.The stability of surrounding rock below are closely related with degree of influence during the up coal seam mining, the different way of coal seam mining leand a different whole mechanical environment under roof, such as when the coal seam adopted longwa ll caving mining method, the roof boundary conditions;are destroyed rock between the layers,If the method is pillar mining, after coal mining goaf on the residual coal pillars in the bottom of form concentrated stress, when the coal seam mining under the roof boundary conditions for the concentrated load boundary conditions.the different boundary conditions, will appeared to present a diversity pressure in coal seam miningThis article respectively study Ultra-Close Multiple-seams Mining in sanquang longwall mining and wangfeng pillar minging,using method of theoretical analys is, numerical simulation and field measurement to study roadway support research. The main research results are as follows:(1)Have studyed the stability of coal pillar,and stress distribution in coal floor below pillar; Theoretical analysis of the roadway in the non-uniform stress field, the supporting structure prone to partial overload, produce a local failure, could eventually lead to the unstability of the supporting structure; Calculate and determine the reasonable distance within coal seam mining below;(2)Adopting the elastoplastic theory and the slip line field theory to calculate damage depth range after mining, and accordingly divided the layer into three types: as less than 2m of the roadway, 2-4m roadway roadway, and more than 4m,respectively supporting the three type and verified by field practice;(3)Through the analys is of 8# coal in wangfeng pillar group of roadway surrounding rock we can conclude that: the roadway roof pressure distribution characteristics under the pillar group is the volatility changes pillar goaf are studied under the conditions of roadway surrounding rock stress and mechanical properties analys is was carried out on the bracket; Knife under the column group of roadway surrounding rock deformation and the location of the damage showed strong correlation:(1) at the bottom of the coal pillar coal strata approximation for vertical stress under maximum principal stress, the level of stress for the minimum princ ipal stress pressure stress field;(2) the maximum princ ipal stress under the goaf of coal rocks is horizontal stress approximately, the vertical compressive stress field of stress for the minimum principal stress;(4)The thickness between 8, 9# coal layer in wangfeng is only 0.75 m, in the condition, the roof is loose and broken, easy to leakage, the reinforcement of the surrounding rock, can only use a metal stent. Through the analysis of failure mechanism and failure characteristics of surrounding rock of roadway in different location combining with the analys is, proposed the corresponding mechanical properties of roadway surrounding rock stability control countermeasures.The above research achieved good results in practice, it has a certain reference value for similar conditions of roadway surrounding rock stability control.