Deep mining faces high temperature and pressure environments. In order to understand the adsorption gas characteristics of deep coal bodies，an isothermal adsorption experiment was conducted to study the coal's adsorption characteristics under different temperature and pressure conditions. The experiment examined both macro and micro perspectives of the coal's adsorption behavior，molecular dynamics isothermal adsorption simulation and theoretical analysis. The research results are as follows. When the gas pressure is low，the difference between the absolute adsorption capacity and the excess adsorption capacity is not significant at different temperatures. When the gas pressure is high，the difference between the absolute adsorption capacity and the excess adsorption capacity increases with the increase in temperature. In the process of gas pressure increasing from 0 to 20 MPa，the amount of gas adsorbed by coal is divided into three stages. The growth pattern consists of a rapid increase during the initial stage，followed by short-term stability in the middle stage，and a gradual decline in the later stage. The equal adsorption heat and adsorption capacity of coal meet the exponential function relationship. The temperature-pressure adsorption model based on the equivalent adsorption heat deduction can predict the quantity of isothermal adsorption gas under any temperature and pressure conditions，and the relative error between the measured and predicted values is 10%.

To mitigate the long-term impact of horizontal loads (such as wind，waves and currents) on offshore wind turbines，a finite element model for the ultimate bearing capacity of heterogeneous clay single-pile foundations was developed using ABAQUS software. Temperature was employed as a virtual variable to reflect the relationship between shear strength of heterogeneous soil and depth. The Model Change technique was employed to achieve geostatic equilibrium，and the obtained results regarding the variation in horizontal loads on single-pile foundations were compared with centrifuge test outcomes to validate accuracy. Combining the failure modes of soil under horizontal ultimate loads for both rigid and rigid-flexible piles，the influence of parameters such as aspect ratio，soil elastic modulus coefficient and pile-soil friction coefficient on the horizontal ultimate bearing capacity of single pile foundations was analyzed. The findings indicate that with an increase in pile embedment depth，the pile transitions from a rigid state to a rigid-flexible state，and the soil failure mode shifts from wedge and rotational failure to wedge，full-flow and rotational failure. The soil elastic modulus coefficient has a minor impact on the horizontal ultimate bearing capacity of single-pile foundations，while the aspect ratio and pile-soil friction coefficient exert a significant influence.

In order to explore the influence of initiation sequence on the crushing effect of open steps and the surrounding environment，the LS-DYNA simulation software was used to calculate the step blasting model under different initiation sequences. First，the physical and mechanical characteristics of the model under different initiation orders were analyzed. Then，the field test was conducted to verify the simulation results and study the influence of the initiation sequence on the blasting vibration strength and rock crushing degree. The results show that the stacking effect，which changes the stress wave，shows the breaking effect and blasting vibration strength. The hole-by-hole blasting technology can effectively reduce the blasting vibration so as to reduce the adverse effects on the surrounding environment，but the rock-crushing effect is not ideal; the rock passing rate is 81.52%. Compared with the hole-by-hole blasting，the passing rate of wave sequential blasting gravel is increased by 11.68%，and the amount of single-hole collapse is increased by 16.8% when the hole net parameter is increased to 3 m×7 m，which effectively reduces the explosive consumption and reduces the comprehensive cost. However，it produces a large blasting vibration strength，which needs to pay attention to the impact on the surrounding environment.

To explore the enhanced permeability of gas-containing coal seams and improve extraction efficiency，high-pressure gas fracturing tests under different impact directions were performed by a self-developed true triaxial high-pressure gas impact rock fracturing test system. The test variable was the angle between gas impact direction and maximum horizontal principal stress. High-pressure gas impact tests were performed under the actions of three triaxial stress，and rock fracture morphology and acoustic emission response were obtained at angles between the impact direction and the maximum horizontal principal stress of 0，30，45，60，and 90°. The results indicated that the rock fracturing process caused by high-pressure gas presented five significant stages including the impact crack initiation stage，air pressure rising stage，crack propagation stage，air pressure stabilization stage，and pressure attenuation stage; High-pressure gas impact caused vertical and horizontal cracks. Vertical cracks were deflected，and the deflection angle increased with the increment of the jet angle. Moreover，the crack deflection points gradually moved away from the drilling hole，and the horizontal fracture surface took on a shape of low in the middle and high in surrounding areas. The maximum gas pressure increased with the angle between the jet direction and the maximum principal stress，and the peak pressure represented a linear increment from 0 to 90°; The acoustic emission signals analysis indicated that rock impact failure was primarily caused by tensile failure and supplemented by shear failure. However，as the jet angle increased，it gradually became a tensile-shear composite failure dominated by shear failure.

To deeply explore whether ride-hailing services directly affect road traffic crashes and whether they indirectly affect road traffic crashes by changing the usage of buses and private cars，based on panel data from 114 cities in China from 2005-2017，the multi-period DID method and the causal steps method are used to estimate the impact mechanism of ride-hailing services on road traffic crashes. The results show that the entry of ride-hailing services increases road traffic crashes by 5.6%，and this conclusion still holds after performing robustness tests such as parallel trend and Propensity Score Matching-DID. Ride-hailing services significantly reduce public transit usage by about 19.3%，thus indirectly increasing road traffic crashes by 0.71%，which indicates that public transit usage plays a mediating effect. Ride-hailing services significantly increase private car usage by 5%，thus indirectly increasing road traffic crashes by 0.14%，which indicates that private car usage plays a mediating effect. The decrease in public transit usage is an important reason why ride-hailing services indirectly increase road traffic crashes. Government departments should strengthen the regulation of ride-hailing services，while encouraging the synergistic development of ride-hailing services and public transit.

In order to achieve the goal of cost reduction and efficiency enhancement in emergency logistics，the comprehensive capabilities of emergency logistics suppliers were evaluated from the perspective of suppliers by utilizing the Cloud TOPSIS. Based on the characteristics of emergency logistics，a comprehensive evaluation index system for emergency logistics suppliers was constructed from five aspects: emergency response capability，material quality，cost control，emergency response flexibility，and internal and external conditions of the enterprise. Drawing on the ideas of game theory，the objective weights obtained by the improved entropy weight method and the subjective weights obtained by Analytic Hierarchy Process (AHP) were taken as game opponents to determine the optimal combination of weights. The cloud model was used to solve for the decision-making cloud of indicators and the weighted cloud for the fuzzy qualitative evaluation semantics quantification of suppliers. Finally，using the TOPSIS method，the positive and negative ideal solution sets were constructed，and the relative closeness to these ideal solutions was determined by calculating the distance of alternative solutions，thus identifying the optimal alternative. Research indicates that the Indicator Decision Cloud can accurately quantify evaluative language，and the results of the Cloud-TOPSIS method are more reasonable. In the ranking of suppliers' relative closeness，the difference between the best and worst calculated by the Cloud-TOPSIS method is 0.331 5，while for the TOPSIS method，it is 0.088 2，with a difference of 0.243 3. This suggests that the evaluation results of the Cloud-TOPSIS method have a greater degree of differentiation，which can more intuitively assist decision-makers in making optimal choices.

In order to reduce the casualties and property losses and improve the emergency rescue capability in coal and gas outburst accidents，an SSA optimized SVM was proposed to evaluate the emergency rescue capability of coal and gas outburst accidents. First，according to relevant literature and research reports，four first-level indicators，including emergency prevention ability，emergency preparedness ability，emergency response ability and recovery and rehabilitation ability，were constructed. These indicators were further subdivided into 18 second-level indicators，and the score data of each indicator was used as the model training dataset. Then，the network analytic Hierarchy process (ANP) and entropy weight method (EWM) were used to determine the subjective and objective weights of each evaluation indicator under the mutual influence，and the Lagrange function was used to merge the weights to obtain the optimal weights. SSA optimized the radial basis parameters g and penalty factor C of SVM. The result of optimal weight calculation was used as the input of the SSA-SVM model，and the expected value was used as the output for linear regression prediction. Finally，taking a mine in Hebei Province as an example，the prediction results of the SSA-SVM model was compared with the traditional SVM，particle swarm optimization algorithm (PSO) optimization SVM and Whale optimization algorithm (WOA) optimization SVM，and the predicted results and the expected values were analyzed. The results show that the prediction results of the SSA-SVM model are consistent with the reality，and the average absolute error decreases by 8.04%，5.15% and 4.82%，respectively，compared with other models，which proves the superiority of the proposed model. This model can be applied to the evaluation of the emergency rescue ability of coal and gas outburst accidents in actual mines.

The association between MHO and HUA and whether liver enzyme abnormalities could modify this association were studied. The cross-sectional study was conducted using 6，868 steelworkers in Hebei Iron and Steel Company who participated in occupational medical examinations as the study population. The data were analyzed using logistic regression models and interaction effect model. The results show that，in a multiple adjusted logistic model，the risk of HUA is increased 2.13-fold (odds ratio (OR)=2.13，95% confidence interval (CI): 1.08-4.21) for metabolically healthy generalized obesity (MHGO). The risk of HUA is increased 2.25-fold (OR=2.25，95%CI: 1.14-4.45) for metabolically healthy abdominal obesity (MHAO). In stratified analysis，in the group with elevated liver enzymes，the prevalence of HUA in steelworkers with MHO(MHGO and MHAO) is significantly higher than that in the group with normal liver enzymes，and the interaction between obesity phenotypes and liver enzyme levels has a statistically significant effect on HUA (P<0.05). MHO is associated with a high prevalence of HUA. Liver enzyme levels may alter the relationship between MHO and HUA.

In order to analyze the content characteristics of international occupational health policies and promote the high-quality development of China's occupational health career，the occupational health policy texts of five countries，namely China，the United States，Japan，Australia，and Sweden，were taken as the research object. Relying on theory of policy tools and PMC index model，a quantitative analysis of the occupational health policies of the five countries was conducted under the international comparative perspective，and suggestions for optimizing China's occupational health policies were then put forward. The study shows that the five countries tend to shape the macro-environment and human and material resources of occupational health governance through environmental and supply-side tools and neglect the pulling role of demand-side tools. Compared with other countries，China has an excellent performance in terms of policy nature，policy recipients，policy focus，and incentives and constraints，and there is still some room for development in terms of policy effectiveness，policy perspectives，and policy subjects. Enhanced comprehension of the issue concerning the imbalanced allocation of occupational health policy tools is imperative. In light of the intricate and dynamic characteristics inherent in managing occupational health for workers，the imperative lies in providing enhanced guidance and support，particularly to those susceptible to mental health hazards.

In order to better develop and sustainably utilize saferesources (which is newly created composite word that means the resources on safety & security in this paper)，the disciplinary theory and its embryonic form of saferesourcesology (which is newly created composite word that means the science of resources of safety & security in this paper) were investigated，based on the new prospect that safety & security was a type of extremely popular and important resource. The whole study stood at the height of the science of science and viewed from the perspective of interdisciplinary science，and adopted the research methods of survey research，innovative thinking，theoretical analysis，logical induction and prediction method. Then，the definition and connotation of saferesources and saferesourcesology，the nature and classification of saferesources，the research objects and contents of saferesourcesology，the basic principles and research methods of saferesourcesology，the research directions and prospects of saferesourcesology，etc，were systematically investigated. The results show that saferesources have both the main characteristics of safety & security and resources. The characteristics of saferesources can be divided into two categories: social characteristics and their own characteristics. Eight aspects of main research contents of saferesourcesology are given from different perspectives and levels. Ten basic principles of saferesourcesology are condensed from the fundamental level of the discipline. Typical research methods of saferesourcesology are summarized based on the interdisciplinary nature. The above research results have formed the core foundational theory and disciplinary framework of saferesourcesology，which has references and guides for the follow-up research of the specific contents of saferesourcesology and the acceleration of the formation of an independent new discipline of saferesourcesology.