Abstract:
To address the safety needs of coalburst mines in China and fulfill the national “zero coalburst” management objectives of no casualties, no roadway damage, and no equipment damage, this study proposes the hierarchical prevention and control objectives and technical paths for “zero coalburst”: ① The highest objective is “no coalburst occurrence” with the technical path of “no stress overrun”. Through theoretical derivation, critical stress formulas were obtained for 3 types of coalbursts, namely coal compression-type coalburst, roof tensile-type coalburst, and fault shear-type coalburst. An analysis was conducted on “no stress overrun”, systematically investigating the influence relationships between the actual stress of the 3 types of coalbursts and mining conditions as well as geological conditions, and the relationships between critical stress and the geometric parameters of the coal-rock deformation system and its own physical and mechanical parameters. "No stress overrun" can be achieved by reducing actual stress and increasing critical stress; on this basis, engineering measures for reducing actual stress and increasing critical stress for the 3 types of coalbursts were systematically sorted out. ② The basic objective is “no coalburst damage” with the technical path of “no residual energy”. Through theoretical derivation, formulas for energy release and energy absorption of the 3 types of coalbursts have been obtained. An analysis was performed on “no residual energy”, systematically studying the maximum released energy and absorbed energy of the 3 types of coalbursts. Impact tests on rock samples and support structures were carried out, and the results showed that the drilling structure of rock samples can absorb impact energy and reduce the overall damage of rock samples. Energy-absorbing devices can significantly improve the energy absorption capacity of supports, with the energy absorbed by the energy-absorbing devices accounting for 78.6% of the total energy absorbed by the supports. "No residual energy" can be achieved by reducing the energy released by coalbursts and increasing the energy absorbed by the surrounding rock and supports. The engineering measures for reducing the released energy of the 3 types of coalbursts, the engineering measures for increasing the absorbed energy of surrounding rock and supports were systematically sorted out. ③ The bottom-line objective is “no coalburst injuries” with the technical path of “adequate space guarantee”. The roadway deformation values causing coalburst injuries were analyzed and determined as follows: the section shrinkage rate exceeds 20%, and the support deformation exceeds 20 cm. “Adequate space guarantee” can be achieved by energy-absorbing devices. Energy-absorbing devices can share up to 70% of the impact deformation of hydraulic supports through yielding deformation, which protects the roadway support structure and controls the support deformation within 20 cm. The engineering measures are as follows: Roadways shall be reinforced with energy-absorbing hydraulic supports, and the appropriate type and model of energy-absorbing hydraulic supports shall be selected based on the maximum released energy of coalburst, the direction of impact load and the roadway conditions. This study confirms that the “zero coalburst” prevention and control objective can be achieved through stress control, energy control, and space control, providing theoretical and technical support for coalburst mines to realize “zero coalburst”.