Compaction Mechanical Characteristics And Gradation Optimization Of Waste Rock And Tailings Dry Filling Materials

Filling mining fills solid waste filling materials into goaf to achieve stability of stope and surface.Cemented filling uses cement or other cementing agents as cementing materials for filling,which has high cost.Dry filling has the advantages of low cost and simple operation.It is also an important research direction of filling mining.The gradation of dry filling materials directly affects its compaction mechanical properties,thus affecting the filling effect.The gradation optimization problem of dry filling materials at home and abroad has not been solved well so far.Therefore,it is of practical significance to study the compaction mechanical properties and gradation optimization of dry filling materials,which can guide mine production.Aiming at the compaction mechanical characteristics and gradation optimization of dry filling materials,the effects of porosity,compactness and particle size gradation on the compaction mechanical characteristics of dry filling of waste rock were studied.The compaction mechanical characteristics of single waste rock and waste rock tailings dry filling materials were analyzed from four aspects : axial strain-stress relationship,deformation modulus,compression modulus and fractal characteristics.Taking the compaction mechanical characteristics as the evaluation index,a gradation optimization method of waste rock tailings dry filling materials was proposed.The following conclusions were obtained :(1)Through the research on the influence factors of mechanical characteristics of waste rock dry filling,the change law of porosity and compactness of waste rock is obtained by using the test method of waste rock particle compaction.The influence degree of particle size gradation of waste rock on compaction mechanical characteristics is analyzed by using the discrete degree analysis method.(2)Through the experimental analysis and research on the compaction mechanical characteristics of waste rock dry filling,the compaction mechanical characteristics of waste rock are analyzed from four aspects : axial strain-stress relationship,deformation modulus,compression modulus and fractal characteristics of waste rock.The phase change characteristics of axial strain-stress relationship,deformation modulus and compression modulus in the compression process of waste rock are obtained,and the variation law of fractal characteristics of waste rock with particle size distribution is obtained.(3)Through the study of compaction mechanical characteristics and gradation optimization of waste rock and tailings dry filling material,the feasibility of mixed dry filling was studied from the microstructure of waste rock and tailings.Then the axial strain-stress,compression modulus and fractal characteristics of waste rock tailings mixed samples under different gradations were obtained by the compaction mechanical test of waste rock tailings filling materials.Taking the compaction mechanical characteristics of waste rock tailings dry filling material as the evaluation index,a method of optimizing the dosage of tailings by the natural porosity of waste rock with different particle sizes is proposed,so as to realize the grading optimization of waste rock tailings dry filling material.