In order to study the compressive strength and crack evolution form of roadside filling body, the strength and acoustic emission of filling body under different loading rates were studied by using PCI-2 acoustic emission tester and pressure testing machine. The crack evolution process of the specimen under different conditions was analyzed, and the compression failure mode, failure mode and internal energy change law of the filling material were obtained, and then the deformation failure and crack evolution law of the filling material were mastered. The results show that the mechanical properties of the filling body are related to the loading rate, while the peak strain is not obviously affected by the loading rate. The cumulative Hit number and cumulative energy of filling materials increase with the increase of loading rate. The higher the Hit number and energy of the filling material, the earlier the internal damage occurs, the earlier the crack evolves, and the easier it is to form instability failure. The abrupt change of the cumulative Hit number and cumulative energy value with time can be used as a reference for entering instability failure.
Gangue filling is an important green mining technology, but it is difficult to realize the precise control of the filling and compaction effect, so that the required dense filling rate and filling material parameters cannot be guaranteed. The study of uniaxial compression meso-mechanical properties of gangue particle clusters is of great significance for maximizing the use of gangue filling technology. In this paper, in order to study the mechanical response of displacement, breakage and force chain evolution in the process of compression and compaction of gangue particles, the numerical simulation method based on discrete element is used to establish the model of gangue particle cluster. Through the overflow test, friction physical experiment and steel drum compression test, the compression simulation of gangue particle cluster is carried out, and the physical and mechanical parameters of gangue and the bonding parameters of particle cluster are obtained. The results show that with the compression process, the bonding bond presents the conversion process of bonding-breaking-contact and the crushing sequence of particle cluster tip-whole particle cluster. The formation and extension of the force chain correspond to the fragmentation, displacement and mosaic of the block, and the elongation and penetration of the high stress force chain correspond to the fragmentation of the particle cluster, which will lead to the increase of the stress concentration. The degree of influence on the stress-strain curve of gangue particle clusters from large to small is : particle shape, particle size, loading speed. It provides a theoretical basis for precise quantitative control of gangue solid compaction effect.
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