Abstract
Abstract In order to effectively predict and control the rib spalling and roof leakage, it is necessary to reveal the deformation and failure mechanism of the chamber and propose the corresponding surrounding rock control technology. Based on uniaxial compression experiments and numerical simulations, it is concluded that coal body damage is dominated by shear failure during uniaxial compression, which indicates to some extent the main form of damage of the surrounding rock in the chamber. Then the combined finite and discrete element method is used to establish a numerical model to reveal the evolution law of fracture in the surrounding rock. The simulation results show that after the excavation of the chamber, a large amount of shear failure occurred in the ribs and the roof. Then those cracks further developed, expanded, penetrated, and finally connected with the surface of the chamber. Under the effect of the mine pressure, the coal body is separated from the surface of the chamber, leading to the occurrence of rib spalling and roof leakage. So it was given that support method by controlling crack development. The grouting and high-strength anchor bolt and anchor cable are proposed to improve the shear strength of the surrounding rock, which helps to reduce the occurrence of cracks, and inhibit the cracks from interpenetrating. An industrial test was carried out in the chamber of Tashan Coal Mine, which showed good control effect of the surrounding rock in the chamber.
Highlights
Coal is China’s major primary energy source, accounting for more than 70% of the total energy consumption [1,2]
The coal sample is placed in the MTS815 Flex Test rock mechanics test system, and the PCI-II acoustic emission test system is used for the real-time positioning test of the whole process of uniaxial compression
In order to further analyze the number of cracks caused by shear failure and tensile failure of coal samples during uniaxial compression and reveal the main failure modes in the compression process, a numerical simulation of a set of uniaxial compression is added
Summary
Coal is China’s major primary energy source, accounting for more than 70% of the total energy consumption [1,2]. The above studies mainly focus on the use of continuous numerical simulation software to reveal the development law of the plastic zone of the surrounding rock of the chamber or roadway or to analyze their stability based on the theoretical calculations. The FDEM is used to simulate the surrounding rock crack development of the chamber, which can accurately reveal the deformation and failure mechanism. The crack development of the surrounding rock of the chamber is analyzed using the model to reveal the mechanisms of rib spalling and roof leakage. Based on the failure mechanism of the chamber surrounding rock, a support method the combines grouting and high-strength anchor bolt and anchor cable is proposed, and the industrial test is carried out in the chamber of Tashan Coal Mine
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