Non-uniform failure mechanism and stability control of mining roadway under deviatoric stress field.

Based on the elastic-plastic theory, the analytical formula of the second invariant J of deviatoric stress at any point around the circular roadway under the non-uniform stress field is derived. The distribution law of J of surrounding rock under the three-dimensional non-isobaric stress field is studied by theoretical analysis and numerical simulation. Combined with the butterfly failure theory of surrounding rock of roadway, the close relationship between the distribution pattern of J and the distribution pattern of plastic zone is found, and the failure mechanism of surrounding rock is revealed.

Numerical and experimental study on smoke diffusion characteristics of tunnel with ceiling beams.

Ceiling beams at the top of tunnels are more common in actual projects. Under the influence of thermal buoyancy, the ceiling structure significantly affects the diffusion characteristics of fire smoke within the tunnel. This study performed several sets of model experiments and numerical simulations to investigate the impact of the height and spacing of ceiling beams on the diffusion of smoke in tunnel fires, which results show that the maximum temperature rise and temperature decay patterns of fire smoke follow exponential changes.

Molecular simulation of the effect of water content on CO, CH, and N adsorption characteristics of coal.

The objective of this work was to investigate the sorption behavior of gases, namely CO, CH, and N, by molecules of coal sampled from Linglu mine under different water inclusion rates. To this end, the adsorption, diffusion, adsorption heat, and potential energy distribution characteristics of the gases in the coal pores at different water inclusion rates were analyzed using molecular dynamics and grand canonical ensemble Monte Carlo methods. The results showed that the adsorption relationship of the coal molecules on CO, CH, and N exhibited a downtrend followed by an uptrend when the water content was increased from 0 to 3.

Study on the Effect of HS on the Adsorption of CH, N, and CO by Anthracite.

In order to study the effect of HS on gas adsorption in a coal seam, the adsorption characteristics of single-component CO, CH, N, and HS and multicomponent HS mixed with CO, CH, and N by anthracite were simulated by using the Grand Canonical Ensemble Monte Carlo (GCMC) method. The results show that the adsorption capacity of CO, CH, N, and HS in anthracite decreases with increasing temperature and increases with increasing pressure. The isothermal adsorption curves of CO, CH, N, and HS and different proportions of HS/CH, HS/N, and HS/CO are highly consistent with the Langmuir equation, and the is above 0.

Molecular modeling of CO affecting competitive adsorption within anthracite coal.

This study aimed to investigate the adsorption properties of CO, CH, and N on anthracite. A molecular structural model of anthracite (CHON) was established. Simulations were performed for the adsorption properties of single-component and multi-component gases at various temperatures, pressures, and gas ratios.

A comprehensive risk assessment method for hot work in underground mines based on G1-EWM and unascertained measure theory.

A risk assessment method for hot work based on G1-EWM and unascertained measurement theory was proposed to prevent hot work accidents in underground mines. Firstly, based on the risk influencing factors and classification criteria for underground hot work operations in mines, a single indicator measurement matrix was constructed using unascertained measurement theory; Secondly, a risk assessment index system for mine underground hot work operations was established. The combination weight coefficient of each index was determined using the order relationship analysis method (G1) and entropy weight method (EWM) and coupled with the single index measurement evaluation vector to calculate the multi-index comprehensive evaluation vector of the evaluation object; Finally, the model was validated and examined using engineering examples, and the evaluation level was determined using confidence identification criteria.