Research on coal mine safety risk evolution and key hidden dangers under the perspective of complex network.

In order to find out the main causes of coal mine safety accidents and improve the pertinence of coal mine safety risk management and control, the identification and analysis of coal mine safety risks and hidden dangers are carried out based on the analysis of coal mine accident reports. Combing the complex network theory, a complex network model for the evolution of coal mine safety risks is constructed. The key elements that affect coal mine safety risk accidents are obtained through quantitative research on the characteristic indicators of the complex network model of coal mine safety risks.

Study on Multifield Migration and Evolution Law of the Oxidation Heating Process of Coal Spontaneous Combustion in Dynamic Goaf.

To study the dynamic evolution law of the oxidation heating process of coal spontaneous combustion in the goaf during the advancing process of the working face, a dynamic model of oxidation heating of coal spontaneous combustion in the goaf was established on the basis of deformed geometry. Through numerical simulation research, the evolution and migration laws of seepage field, oxygen concentration field, temperature field, and high-temperature area of coal spontaneous combustion in the goaf during the advancement of the working face was obtained. The results indicate that the distribution of the bulking coefficient, porosity, and permeability of the falling coal and rock mass in the goaf is nonuniform.

Research and Application of "Concentric Ring" Reinforcement and Sealing Technology for Gas Drainage Boreholes in Soft-Coal Seams.

The problems of lack of stability and difficult sealing of gas drainage boreholes in soft-coal seams directly affect the efficient extraction of gas in these soft-coal seams. After the holes are drilled, the collapsed holes lead to the failure to seal in time, which brings hidden dangers to mine production and causes time and economic waste. In this paper, the viscoelastic mechanics model is used to solve the force of the coal body in the fractured area of the orifice, combined with the theory of the external conditions affecting the collapse of the orifice of the soft-coal seam.

Experimental and Theoretical Study of the Time-Effect-Based Instability Characteristics of the Gas Drainage Borehole Sealing Section in a Soft Coal Seam.

The instability and sealing difficulty confronted by gas drainage boreholes in a soft coal seam weakens the drainage efficiency. To address this problem, the instability characteristics of the sealing section of boreholes are investigated. On the basis of the findings of the mechanical properties of the borehole around the sealing section and in view of the physical and mechanical properties of the soft coal seam, a theoretical analysis was performed.