Research On Bearing Characteristics And Overlying Rock Deformation Control Of Gangue Grouting Filling In Subsequent Space

Coal resources are an important material guarantee for China’s economic and social development.They play a role in ballast and bottom protection in the fields of energy,metallurgy and materials.However,solid wastes such as coal gangue mined with coal have problems such as large emissions,low utilization rate,and high disposal costs.At the same time,excessive mining causes subsidence and damage to the overlying strata,causing a series of problems such as surface subsidence,damage to buildings（structures）,and loss of water resources.In order to achieve the purpose of controlling the deformation of overlying strata while realizing green mining,this thesis takes the 3^-1802 working face of Hongqinghe Coal Mine as the research object,and uses theoretical analysis,laboratory test,numerical analysis and other research methods to study the filling bearing characteristics and overlying strata deformation control effect of subsequent space gangue grouting.The following research results have been achieved:（1）The structural properties of gangue grouting filling materials were studied macroscopically and microscopically.The fluidity and bleeding rate were used as response values.The optimal design response surface method in Design Expert software was used to design,test and optimize the screening.The optimum ratio of gangue slurry in the range of 220-260 mm was obtained.（2）The bearing capacity of gangue slurry under different fluidity ratios is studied by confined compression test.Based on the stress-strain and strain-time curves of gangue slurry under instantaneous and creep compression,combined with the pressure bleeding rate and the height ratio of the pressure body,the evolution law of the bearing performance of gangue grouting is revealed.It is determined that the slurry with a fluidity of 220～240mm has better water retention under pressure.（3）The self-developed upper and lower grouting filling simulation system of fluidized well in broken rock mass was used to design and carry out the slurry accumulation distribution test,and the accumulation distribution law of slurry under different fluidity ratios was revealed.The ratio of 240 mm fluidity of gangue slurry was optimized and the grouting diffusion test was designed to obtain the migration and diffusion law of gangue slurry under different grouting pressures and mass concentrations.（4）Combined with the actual situation of Hongqinghe 3^-1802 working face,the numerical model is established by UDEC7.0,and the control effect of different equivalent filling rate grouting filling overburden displacement and stress distribution is analyzed.（5）Based on the geological conditions and filling area profile of the 3^-1802working face in Hongqinghe Coal Mine,a grouting filling scheme was designed and the effect of surface subsidence was predicted.The thesis has 63 figures,50 tables and86 references.