Tunnel construction projects in China have developed rapidly，and significant dust hazards are associated with drilling and blasting construction. To improve the effectiveness of spraying to reduce dust in tunnels，this article uses digital simulation and a tunnel model was created using ANSYS. The variations in dust mass concentration distribution under different conditions，such as surrounding rock temperature，jet velocity，and nozzle diameter，were investigated in the study. The results show that as the surrounding rock temperature increases，dust movement becomes more intense，which significantly affects dust reduction efficiency. The dust capture effect of atomized water droplets decreases with the increase in surrounding rock temperature. With the increase of water jet velocity，the water pressure in the jet pipe increases，improving the dust capture effect of the droplets. Dust reduction efficiency decreases with increasing nozzle diameter. When the nozzle diameter is too large，the ability of water mist to capture particles weakens. Conversely，a smaller nozzle diameter improves dust reduction efficiency. However，if the nozzle diameter is too small，too much splash water spray rather than affect the efficiency of the dust.

To optimize the professional talent training objectives，curriculum structure，and teaching syllabus of hazardous chemicals safety supervision，the state-of-the-art knowledge system and professional capabilities of hazardous chemicals safety supervision personnel were analyzed. Questionnaires and interviews were used to investigate the recruitment needs，on-the-job training，requirements，and school-government cooperative model for hazardous chemicals safety supervision positions. The results showed shortcomings such as insufficient talents trained in hazardous chemicals safety supervision，imperfect professional knowledge system，and mismatched professional capability structure. Hazardous chemicals safety supervision personnel should master professional knowledge such as laws and regulations，safety management skills (e.g.，integrity and process safety management)，chemical processes，and chemical reactions. Furthermore，professional capabilities in risk assessment (e.g.，equipment，processes，and instrument systems)，chemical reaction analysis，and chemical process simulation analysis should be enhanced.

In order to study the effect of liquid CO₂ injection on coal spontaneous combustion heat production and gas release in the gob with high gas content and easy spontaneous combustion，the gas desorption test system was composed of a self-made variable temperature chamber and desorption instrument to simulate the influence of liquid CO₂ injected into a high-temperature point of gob on coal sample temperature and coal gas desorption amount and analyze the change of gas desorption energy of coal sample under corresponding coal body gas pressure and different temperature during the process of "falling to rising" temperature change. The results show that the temperature of the coal sample will stabilize at a lower level，and the gas will stop desorbing within 60 minutes to 100 minutes after the liquid CO₂ is injected. After 100 minutes，the cold energy gradually runs out，and the coal continues to oxidize and heat up，and the gas resumes desorbing with an increasing desorption rate. The cold energy released by the liquefied CO₂ gasification and the CO₂ gas has an excellent inhibitory effect on reducing coal temperature and gas desorption. When the coal sample temperature is between 10 and 30 ℃，the coal is in a low energy state. In this temperature range，the internal coal is more likely to cause the adsorption heat value to stabilize. The decrease in the surface free energy of the coal body will also present a stable trend.

To improve the efficiency of urban sewage pipeline defect detection，reduce resource wastage resulting from indiscriminate inspection methods，and mitigate environmental safety risks，the XGBoost model was used to predict the probability of urban sewage pipeline defects. Firstly，the causes of sewage pipe defects were statistically analyzed to determine key indicators that can characterize the pipeline defects as the inputs of the XGBoost model. Secondly，appropriate objective functions and base learner parameters were selected. Then the model training and optimization were performed by a grid search algorithm to determine the key parameters of the base learner. Finally，the XGBoost model prediction performance was validated against an area of the sewage pipeline network in Zhongshan，Guangdong province. Moreover，the main factors and paths affecting defect probability were investigated based on the model output，and the defect probability of the sewage pipe network in the area was divided into 4 different levels for visualization.The results indicated that the average area under curve (AUC) of the XGBoost model was 0.97 under 10-fold cross-validation with a prediction accuracy of 93%. Pipeline depth，slope，and length had the greatest impact on the probability of pipeline defect. As the pipe length increases，the sewage pipe defect probability will increase if the slope becomes greater and the buried depth becomes shallower.

In order to quantify the psychological changes of crowds and the impact of competitive factors on the behaviors of evacuees in emergency evacuation situations，a dynamic model was constructed that closely links the state of personnel psychological state with competitive influencing factors. In this model，the crowd was divided into three categories based on individual behavioral characteristics: independent evacuees，cooperative evacuees，and competitive evacuees. Three major factors influencing individual decision-making during the evacuation process were analyzed in depth: personal characteristics，social guidance mechanisms，and environmental factors. Specific parameter values were set，and SD were employed to simulate and study the behavioral characteristics of pedestrians during emergency evacuation. The research results indicate that as environmental visibility decreases and panic spreads，the proportion of competitive evacuees significantly increases. Conversely，when there are positive guiding behaviors and acts of helping others in the environment，these positive factors can effectively alleviate the crowd's anxiety and reduce competitive behaviors. Particularly noteworthy is that when multiple factors are coupled，the greater the competitive intensity，the more significant the positive effect of helping behaviors becomes. This shows that in highly stressful evacuation environments，positive social guidance and mutual assistance behaviors play a non-negligible role in relieving competitive pressure and improving evacuation efficiency.

In order to solve the heat damage issue brought by deep mining in coal mines，based on ANSYS simulation software，the roadway heat insulation model was constructed. The influence of basic parameters of different heat insulation layers and laying methods on the roadway wall structure was analyzed，and the cooling effect of the heat insulation roadway was further investigated. The results of the study show that the laying of the heat insulation layer could reduce the radius of the peripheral rock heat-regulating circle and slow down the heat dissipation of the peripheral rock，and the three ways of laying the heat insulation layer have little effect on the temperature field of the peripheral rock. Compared with the temperature of the non-insulated support layer，the average temperature of the support layer is reduced significantly by laying of the heat insulation layer in the rock-adhering type，whereas the opposite is true for wall-adhering type and the sandwich type. The increase in the thickness of the heat insulation layer and the decrease in the heat conduction coefficient of heat-insulating material could increase the heat-insulating effect，and 7cm is the optimal thickness of heat insulation layer. Excessive inlet wind speed or air temperature will affect the cooling effect of heat-insulated roadway. Heat-insulated roadway is suitable for high temperature roadway with low wind speed，low inlet air temperature and long ventilation distance.

To effectively prevent and control the risk of subway waterlogging accidents，a quantitative analysis method integrating the AcciMap model，FAHP，and triangular fuzzy DEMATEL-ISM method was proposed to investigate the causes of urban subway waterlogging accidents and their coupling associations. Accident causation factors were selected from the system level through AcciMap model. FAHP was used to integrate expert opinions and determine expert weights. The DEMATEL method was used to calculate the importance of accident causes，ISM method was used to reveal the relationship between factors，and a multi-level ladder stepwise graph was constructed. The model was validated by waterlogging accidents on the Zhengzhou subway. The results showed that the core contributing factors leading to the incident were inadequate awareness and prevention measures of major disasters by the management department，the lack of diligence in supervision and inspection duties by regulatory authorities，and ineffective response and handling by operational departments. These factors can be paid special attention to prevent system failures.

In order to improve the theoretical guidance of safety training and promote the effective promotion of safety training in enterprises，a safety training curriculum system framework based on "principle，law，technique，instrument，power，and goal" was created by applying the related theories such as the ACT training method，safety-Ⅰ and safety-Ⅱ. Then，important training points and the level of mastery of knowledge for various types of employees were clarified，and the application study was conducted. The results show that the training covers six dimensions: safety management objective，safety ideology principles，safety laws and regulations，safety management requirements，safety management tools and safety production situation. The 77 sets of video courses made according to the framework of the developed safety training course system have achieved good feedback in application. It can offer enterprises some direction and a point of reference when creating training materials，making training schedules and setting up safety training.

To understand the characteristics of goaf air leakage and gas migration in different mining periods of Y-type ventilation working face without coal pillar mining，97312 working face in Sihe No.2 coal mine of Jinneng Holding Equipment Manufacturing Group Co.，Ltd. was selected. The sulfur hexafluoride (SF₆) tracer gas approach was used to determine the air leakage area distribution，air leakage type，and air leakage volume of 97312 working face and the roadways under different connectivity states with the adjacent 97311 working face goaf. The air leakage flow field distribution and gas migration characteristics in the goaf area were analyzed by numerical simulation. The results showed that 97312 working face had four air leakage areas of positive pressure-negative pressure-positive pressure-negative pressure along the wind direction. The main air intake roadway 97222 had positive pressure leakage. The air return roadway 97224 had mainly negative pressure air leakage along the gob-side entry retaining section，but positive pressure leakage was prone to occur near the extraction pipe and in the area where the roadway was severely deformed. After connectivity with the adjacent goaf area，an additional air leakage path was created. Moreover，the connection status with the adjacent goaf affected the internal air leakage flow field and gas migration of the goaf. Air leakage from the 97311 goaf area carried gas to the 97312 goaf，causing an increase in gas volume fraction in the 97312 goaf，working face，and the gob-side entry retaining section of the 97224 roadway. After the closure of the 97311 working face，the gas volume fraction near the connected goaf area decreased.

To drive multi-stakeholder work safety governance in enterprise-intensive areas such as industrial parks，the dynamic mechanism for forming a multi-stakeholder work safety governance model was explored. Firstly，the key stakeholders involved in the industrial park work safety alliance were identified through text-based data mining. Subsequently，a comprehensive investigation was conducted on the development process and governance model of the work Safety Alliance in Suzhou Industrial Park. Finally，an alliance network was proposed to analyze the translation process based on ANT. Then，the dynamic mechanisms of the Industrial Parks work Safety Alliance were investigated. The results indicated that the benefits of resource exchange could be balanced by developing a work safety resource-sharing platform and proposing a multi-agent governance mechanism in a regional work safety alliance，which can promote multiple stakeholders' collaboration in work safety governance. Furthermore，the active mobilization of core actors，coupled with concerted efforts from both internal and external parties，contributes to the efficient operation of the alliance.