Study On Reasonable Filling Ratio In Solid Backfilling With Gob-side Entry Retaining Mining

The environmental problems caused by coal mining become more serious,State and governments place a high value on the coordinated development of coal mining and environmental protection,Solid waste in mining area apply to backfill mining is imperative.On the engineering background of backfilling with gob-side entry retaining mining face in Hu Lu Su coalmine,which belongs to Zhong Tian He Chuang company.Based on the achievements of surrounding rock movement regularity in backfill mining researched by the experts at home and abroad,the characteristics of strata movement and behaviors at different filling ratio,and the physical and mechanical properties of solid filling materials were studied systematically in this thesis through field investigation,theoretical analysis,laboratory test,numerical simulation.The primary achievements as follows.(1)The deformation characteristics of gob-side entry retaining and the reasons are stated in this paper based on the law of strata movement.Research shows that filling ratio and the physical and mechanical properties of solid filling materials are main factors to affect the deformation of gob-side entry retaining at the same supporting condition,so it would be of great significance to research the reasonable filling ratio to control the displacement of surrounding rock of stope and gob-side entry retaining.(2)The physical and mechanical properties of gangue from coal washery and TBM driving,flyash from coal plant are researched in this thesis.It has been discovered that gangue from TBM driving and flyash can’t directly filling in gob on account of its low intensity,the gangue from coal washery has high intensity because of low porosity aperture.The filling body constitute of above-mentioned three filling materials in different proportions that gangue from coal washery more than gangue from TBM driving and gangue from TBM driving more than flyash has been compacted in laboratory.The most reasonable proportion of solid filling materials and its relationship between elastic modulus and vertical stress are discovered by laboratory test.(3)It will prevent key stratum from breaking and create better strata stress environment at filling ratio are 70% and 80% after using FLAC3 D software to research law of strata movement and behaviors at filling ratio are 50%,60%,70%,80% and 90%.So the stability of gob-side entry retaining can be improved at filling ratio are 70% and 80% due to pressure relief caused by the strata near coal seam breaked.(4)The deformation and strata behaviors of strata around gob-side entry retaining at filling ratio 70% and 80% are analyzed by rebuilding more accurate numerical model.When filling ration is 80%,the plastic zone and maximum stress in surrounding rock of gob-side entry retaining and its deformation are less than when filling ratio is 70%.So we draw a conclusion that the most reasonable filling ratio in backfilling with gob-side entry retaining mining is 80%.There are 60 figures,6 tables and 86 references in the dissertation.