Load-Bearing Compression Behaviors Of Granular Backfill Materials Incorporating Particle Breakage Effect

As a non-continuous medium,the granular filling material is composed of particles with different particle sizes,which are compressed and deformed under the load of the overlying rock layer and accompanied by particle breakage.Particle breakage changes the particle size gradation and density of the granular filling material,which in turn affects the subsequent compression deformation behavior.In order to reveal the mechanism of particle breakage effect on the compression deformation of granular filling materials,this paper developed a modular granular filling material load-bearing compression test system,and designed an overall test process and single factor rotation test scheme including the steps of measuring particle breakage characteristics and loadbearing compression characteristics,analyzed the particle breakage gradation evolution and particle breakage fractal features using comprehensive research methods such as theoretical analysis and experimental testing,obtained the effect of different main control factors on the particle breakage and load-bearing compression characteristics of granular filling materials,and studied the relationship between the particle breakage characteristics and the load-bearing compression characteristics of granular filling materials.The following major research results have been obtained.(1)Developed the load-bearing compression test system of granular filling materials,which includes two modules of sieving test and load-bearing compression,designed a single-factor rotation test scheme of load-bearing compression.(2)Analyzed the gradation evolution characteristics of granular backfill material before and after loading and compression,and determined the quantitative characterization method of granular backfill material based on Tyler fractal model,studied the influence of different main factors on fractal characteristics of particle breakage of granular filling materials before and after loading and compression.(3)Studied the law of compression deformation of granular filling materials under different main controlling factors,and analyzed the distribution of surface porosity of granular filling materials after compression,established the relationship between the compression deformation of granular filling materials and the main controlling factors.(4)Studied the relationship between the compression deformation and the particle breakage of bulk filling materials based on the grey relational theory,and analyzed the relationship between the particle breakage and the main controlling factors,revealed the internal cause of the influence of particle breakage on the compression deformation of granular backfill materials.The paper has 50 figures,16 tables and 92 references.