Study On The Setting Of Water-Proof Coal Pillar In Fully Mechanized Caving Mining At 7401 Working Face Of Zouzhuang Coal Mine

When mining under water,the retention of water-proof coal(rock)column is related to the safety production of the whole mine.The water proof coal(rock)this column method is usually in accordance with the "three ti mes"(2017 edition)of norms,the theory and practice results show that the empirical formula calculation in the "three under" specification lead water fracture zone height of full-mechanized caving mining has certain limitations,so you need to determine a reasonable theoretical formula to forecast the water fractured zone height of full-mechanized caving mining,so as to determine the water proof this reasonable size of coal(rock)column,the water inrush of full-mechanized caving mining under the nearly loose bed collapse disaster prevention has important practical application value,can be further liberate trapped coal,improving mining limit,At the same time,it has the value of popularization and application to the domestic similar mining.This paper is to huaibei ZouZhuang coal mine 7401 working face as the research object,according to the existing mine geological data and physical and mechanical properties of coal strata,the in-situ drilling construction,deep soil,wind oxidized rock mineral composition analysis experiment and theoretical analysis,numerical simulation method,to ZouZhuang mine 7401 working face of waterproof coal pillar of reasonable design,is studied.(1)investigate zouzhuang mine,collect relevant field data,further determine the experimental site and collect test materials,and analyze the geological and hydrogeological characteristics of mine and working face.(2)Based on core identification and statistical results of borehole data,the bottom depth and lithological composition of weathered zone of bedrock in zouzhuang mine are analyzed,and the determination of its engineering geological properties is of great significance to the reduction and protection of coal-rock pillars under extremely thick loose bed and the increase of mining upper limit of coal seam.Through four Zou Zhuang ore mining area of multiple drilling data analysis-7401 face soil types are mainly sand-shale rock contact contact zone and contact with clay,shale,study working face of deep soil rock contact zone can be as a waterproof layer,which can further improve by using the method of reducing waterproof coal pillar mining upper limit.(3)Take working face in a certain depth of soil sample and drilling core sample test,the test of deep soil,and the wind oxidized zone of rock mineral composition,further study on its engineering geological properties,through the analysis of the rock and soil samples drawn montmorillonite has a good waterproof performance,water absorption expansion,can make the crack bridging,inhibit the development of crack,reduce the water flowing fractured zone height.(4)By "three under" specification experience formula,multi-factor fitting formula and other experience formula of working face water flowing fractured zone height,at the same time to Zou Zhuang coal mine 7401 working face as the prototype,on the basis of survey and drilling histogram and working face in coal rock physical and mechanical parameters,by using numerical simulation software FLAC3 D analysis of coal seam mining process,the thick loose bed of full-mechanized caving mining face under the development of conductivity fracture zone height.By comparing the height of the water-conducting fracture zone obtained by various theoretical calculation formulas,the multi-factor fitting formula,other empirical formulas and the height difference of the water-conducting fracture zone predicted by the numerical simulation are obtained,showing a certain uniformity.Finally,the height of the water-conducting fracture zone is determined to be 109 m.(5)Analysis under different soil-rock contact type,the thickness of protection layer,through the hydrogeological conditions,on the basis of its water body type,the aquifer,the occurrence condition of mining water level is determined,such as its high waterproof safety coal(rock)column is greater than or equal to the sum of water flowing fractured zone height and covering layer thickness,through calculation and finally the waterproof coal(rock)of safety pillar of reasonable design,the height is 140 m.The results of research certaining reference value for raising the upper limit of mining in the 7401 working face of Zouzhuang Coal Mine.At the same time,it has reference significance for the prevention and control of water inrush in Huaibei area and similar mines in China.