Abstract:In order to improve the effect of dry filling of waste rock and improve the filling strength, this paper studies the compaction mechanical characteristics and influencing factors of dry filling of waste rock utilizing physical tests and theoretical calculations. The results show that the particle size gradation of the sample and the continuity of the gradation have a great influence on the compactness of the sample. The compactness of the continuous gradation is lower and the compressive strength of the sample is stronger. Through range analysis, the influence of gradation coefficient n on axial strain is greater than that of maximum particle size D ; the axial strain-stress curve of the specimen shows that the main source of the macroscopic deformation of the specimen is the direct compression and filling of the pores. The deformation modulus-axial stress curve shows that the particle size distribution of the waste rock sample is perfect, and there should be a reasonable proportional relationship between the particle sizes in each range so that the sample reaches a stable state through less axial strain. The fractal characteristics of the sample show that the reasonable Taibo coefficient n and the maximum particle size D can improve the crushing degree of the waste rock particles and improve the compressive strength of the sample. The optimum particle size gradation of waste rock was determined: n = 0.4, D = 30 mm. The research results have a certain guiding significance for the dry filling of waste rock.