Case Study on the Mechanism of Influence of Stoppage on Ground Pressure under Different Rates of Advance

Abstract

Because of daily maintenance, equipment damage, gas overrun, and other force majeure factors, the continuous stopping of the working face causes the roof pressure to accumulate, which leads to causing accidents such as coal wall spalling and roof falling. To address the roof safety problem caused by continuous stoppages, the 620 working face in the Huangling mining area is taken as the research object. Through field measurement, theoretical analysis, numerical simulation, and other research methods, the influence and mechanism of stopping pressure under different rates of advance are studied. The results show that the velocity factor of roof load transfer is positively correlated with the advancing velocity of the working face; the reasonable length of the suspended roof is mainly affected by the number of caving holes and the effect of pressure relief; and comparing the two stages of advance speed of 4.8 m/d and 12.8 m/d, the periodic weighting step distance of the latter increases by 24.4% compared with the former, and the rate of increase of support load caused by stopping mining increases by 42.1% compared with the former. The roof pressure accumulation caused by stopping mining is increased. Taking appropriate measures for local forced caving of the working face can release the roof pressure and reduce the risk of local caving of the working face. The study can provide a theoretical basis for roof control of continuous stopping under similar engineering conditions.

Research on process parameter optimization of irregular coal face

“…High loading rates increase the tensile strength of rock, the loading rate of maximum principal stress and the unloading rate of minimum principal stress in the coal body in front of the coal wall, and the strain energy density of shallow coal body, which leads to the increase of the risk and damage degree of pressure bumping in surrounding rock. Liu 18 and Gao 19 used FLAC numerical simulation to study the law of mine pressure behavior under different mining speeds, which provided a strong basis for the calculation of support resistance in fully mechanized mining face. Based on the actual situation of the site, Xie Guangxiang 20 – 22 explored the influence of the advancing speed of the working face on the stress of the surrounding rock of the roadway through FLAC2D, and concluded that the appropriate mining speed was helpful to the stability of the roadway.…”

Research on the Laws of Overlying Rock Fracture and Energy Release under Different Mining Speeds

“…Given the complex nature of underground environments, relying solely on theoretical analysis to fully understand the dynamics of energy release in mining fields presents significant challenges. As a result, numerous researchers have adopted numerical simulation techniques to investigate the relationship between the advancing speed and the energy released from overlying rock [29][30][31][32][33]. While extensive research has been carried out on the evolution of stress within mining fields, studies specifically addressing the energy released from mining activities are comparatively scarce.…”