Research On Goaf Filling Paste Material Based On Coal Gangue

Coal gangue paste material is made of coal gangue,fly ash,cement and admixture with certain particle gradation.In order to master the physical and mechanical properties of coal gangue paste materials and provide reference for filling goaf with coal gangue paste materials,this paper studies the paste materials of fly ash group and coal gangue powder group used for goaf filling through indoor orthogonal test,theoretical analysis and numerical simulation.The main results are as follows :(1)The effects of fly ash/coal gangue powder content,cement content,water reducer content and their interaction on the physical and mechanical properties of coal gangue paste materials are obtained by indoor orthogonal test and response surface analysis.(2)The evolution law of compressive strength and elastic modulus of coal gangue paste material with age is obtained by carrying out compressive strength and elastic modulus tests at different ages.The functional relationship between compressive strength and elastic modulus of coal gangue paste material is obtained by fitting.(3)Through the analysis of the whole process stress-strain curve of coal gangue paste material,the stress-strain relationship of coal gangue paste material is determined,and the whole process stress-strain curve equation of coal gangue paste material is obtained.(4)The prediction model of physical and mechanical parameters of coal gangue paste material is established.The prediction equations of fluidity,water retention rate,compressive strength and elastic modulus of coal gangue paste materials with fly ash/coal gangue powder content,cement content and water reducing agent content are obtained,which provids guidance for engineering application and filling simulation of coal gangue paste materials.