![]() ![]() ![]() When it is filled into the goaf, the phenomenon of particle crushing occurs in the process of cyclic compaction by the compaction mechanism. Crushed gangue backfilling material (CGBM) is most commonly used as a kind of solid backfill material for SBCM. Finally, the solid backfill material will serve as the main supporting body to bear the load of the overlaying strata. After that, the compaction mechanism, as a key structure, is applied to push and compact the solid backfill material, which is repeated for several cycles to connect the immediate roof with the required density. Then, the solid backfill material fills the goaf by being unloaded from the discharge port in the scraper conveyor. In the SBCM process, the vertical feeding system transports solid backfill material from the waste storeroom under the mine to the scraper conveyor at the rear of the hydraulic support. At the same time, the gangue heap on the ground surface can be well disposed with the use of the technology, which can significantly reduce environmental pollution. ![]() It can effectively control overburden movement, thus increasing the coal recovery ratio. This technology is aimed at backfilling solid waste, which mainly includes crushed coal gangue and fly ash, into the underground goaf, thus bearing the majority of the overburden load and recovering coal resources under buildings, railways, and water bodies. Solid backfilling coal mining (SBCM) is a green mining technology proposed for use in difficult coal mining situations, such as mining under buildings, railways, and water bodies, and for solving the problem of the opening dumping of gangue on the ground. This study is of great significance for obtaining an in-depth understanding of the mechanical properties of CGBM, as well as providing guidance for the engineering practice of SBCM. The crushing ratio of CGBM was highly correlated to the AE signals, which indicated that AE signals can be used to reflect the particle-crushing situation of CGBM. What is more, it was found that the CGBM samples exhibited an apparent Felicity effect during CACL, and AE signals were the most active during the first loading cycle. The content of newly generated fine particles can reflect the particle-crushing conditions to a certain extent. It also demonstrated that both the crushing ratio ( B g) and the newly produced fine granule content increased with the cyclic loading times. The results showed that the gangue particles were generally in the shape of irregular convex polyhedrons with more edges and angles that were prone to breakage. At the same time, the relationship between particle crushing and AE signals was established. This study implemented an experimental approach to investigate the particle-crushing characteristics and acoustic-emission (AE) characteristics of CGBM during constant-amplitude cyclic loading (CACL). However, the deformation resistance of CGBM is critical for controlling overburden strata movement and ground surface subsidence. In this cyclic compaction process, the particles are crushed, which has a significant effect on the deformation resistance of CGBM. Vibrational motion can be defined as the movement of particles back & forth along with their mean position.In solid backfilling coal mining (SBCM), the crushed gangue backfilling material (CGBM) is generally compacted circularly by a compaction machine in order to reduce its compressibility.The different types of motion are Translation, Rotation, Vibration and Electronic motion.Order of random motion → Solid Order of Degree of freedom → Solid Order of intramolecular forces of attraction → Solid > liquid > gas.Molecular motion can be defined as the motion or movement of constituent particles insolid, liquid or gas.The entire phenomenon from absorbing light by the molecules and later measuring this value of absorbance is known as spectroscopy techniques and can be used for analysing or measuring the movement of constituent particles as well as for identification of the types of atomic or molecular species present in an unknown sample. Different types of atoms and molecules require a different amount of energy to undergo their motion, hence they all have a characteristic value for absorbance of light. They can get this energy by absorbing a certain amount of light such as infrared and can then show their characteristic motion. Measurement of Movement of Particles or MoleculesĮvery atom or molecule requires energy for its motion. Weakest intramolecular force & highest degree of freedom ![]() Weak intramolecular forces when compared to solids ![]()
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