In order to study the evolution characteristics of adsorption of C₂H₄by residual coal in closed area of coal mine goaf，taking non-cohesive coal in Lingxin Coal Mine of Ningxia as the research object，the adsorption of C₂H₄ by coal was tested by volumetric method. The effects of temperature，pressure and particle size on the adsorption capacity，adsorption rate and adsorption thermodynamics were analyzed. The results show that when the temperature is 30-60 ℃，the pressure is 0.15-0.45 MPa and the particle size is 20-120 mesh，the adsorption capacity of C₂H₄ increases with the decrease of temperature，the increase of pressure and the decrease of particle size. The adsorption process changes from fast to slow with time，then tends to equilibrium，and the adsorption rate rapidly tends to 0. When the temperature and particle size are constant，the adsorption rate increases with the increase of equilibrium pressure. When the temperature and pressure are constant，the adsorption rate increases with the decrease of particle size. At the same adsorption capacity，the smaller the particle size is，the lower the equilibrium adsorption heat is. The equivalent adsorption heat of C₂H₄ adsorbed by coal samples with different particle sizes is 0.69-40.23 kJ/mol，which belongs to physical adsorption. The pressure correction coefficient is introduced to fit，and the pressure and particle size are proportional to the reduction of adsorption free energy when the temperature is constant. Under the condition of constant particle size，the temperature is inversely proportional to the decrease of adsorption free energy. The adsorption entropy of C₂H₄ for coal samples with different particle sizes is negative，and the adsorption entropy increases with the increase of adsorption capacity and the decrease of temperature. Under the same adsorption capacity，the larger the particle size，the greater the adsorption entropy.

To explore the slipstream characteristics of 400 km/h high-speed trains passing through tunnels，a three-dimensional，unsteady，compressible and realizable k-ε turbulence model was used to perform numerical simulations to analyze the time evolution and spatial distributions of slipstream in tunnels. In addition，the flow field around the train was zoned according to the times when each part of the train reached and left the measuring point. Five characteristic parameters were used to measure the change of the slipstream speed in each area. The influence of different train formation lengths and tunnel lengths was discussed. The research results show that the change characteristics of slipstream in the tunnel are significantly affected by the train running position and pressure wave propagation. The slipstream peak increases with the increase of train formation length and speed，and the peak arrival time is delayed and advanced. The positive peak value of 8 formation is 68.75% higher than that of 3 formation，and the peak value at 400 km/h is 22.65% higher than that of 300 km/h. Under the same tunnel length，the maximum positive peak slipstream appears at the midpoint of the tunnel，and the fluctuations here are more intense and complex. The influence of pressure wave in the long tunnel on the peak slipstream speed is weakened. When the tunnel length reaches 3km，the positive peak slipstream drops by 30.70% compared with the length of 1km.

In order to address the increasing risk of conflict caused by the difficulty in effectively predicting aircraft point source localization，a time series trajectory prediction model AM-LSTM based on AM and LSTM was constructed，to predict the instantaneous point source location of the aircraft in the airfield area in a short time in the future. On this basis，the contour was expanded according to the aircraft type and glide heading，the aircraft speed was used as the safety distance weight，and the ray method was used to realize the determination of the contour conflict. Urumqi Dewopu Airport was used as an example for validation，and the trained trajectory prediction model was utilized to predict aircraft taxiing trajectories in the airfield area and identified taxiing conflicts between aircraft profiles. The results show that the AM-LSTM prediction model can accurately predict the aircraft movement trajectory in the airfield area，and the average displacement error of the trajectory position prediction in the next 3 s is 1.05 m，and the accuracy of trajectory point position prediction can reach 94.37%. Therefore，it can accurately identify the risk of taxiing conflict on the basis of trajectory prediction，which is conducive to guaranteeing the safe operation of the airfield area.

In order to shorten the identification time of coal spontaneous combustion tendency，firstly，industrial analyzer and temperature programmed test device were used to measure the coal quality index value and the content of coal spontaneous combustion indicator gas at different temperatures. The critical temperature point of low-temperature oxidation was determined by CO volume fraction. Then，the equation between temperature and oxygen consumption rate was fitted through the Arrhenius formula，and the apparent activation energy of each coal sample at different stages before and after the critical temperature was solved. The correlation between the coal quality index value and the apparent activation energy before and after the critical temperature was analyzed by Pearson correlation coefficient method，and the correlation coefficient was calculated. Finally，the coal quality index value with the largest correlation coefficient was selected，and a multiple linear regression model for calculating the apparent activation energy of coal samples was established to analyze and predict the spontaneous combustion risk of coal. The results show that the correlation coefficients between different components of coal quality and the apparent activation energy before and after the critical temperature are significantly different. The negative correlation coefficients between volatile matter and the apparent activation energy before and after the critical temperature are the largest，which are -0.893 and -0.977 respectively. The positive correlation coefficients between fuel ratio and the apparent activation energy before and after the critical temperature are the largest，which are 0.956 and 0.968 respectively. The fitting degree of the established multiple linear regression model can reach 0.912 5 and 0.933 0.

Pool fire caused by fuel leakage seriously threatens engine operation and aircraft safety. To deeply understand the complicated physical mechanisms of pool fire in engine fan cavities，temperature variation characteristics of double fuel pool fire were investigated. Firstly，the physical and numerical models of the CFM56-7B engine fan cavity were established based on the software FDS. Secondly，simulated temperature variations of single fuel pool fire were validated against measurements of the Trent 800 engine fan cavity，and then grid independence was analyzed. Finally，the fire development process and temperature variation characteristics of double fuel pools were analyzed within the fan cavity using several detectors and slices. The results indicated two phases for temperature variation of the double fuel-pool fire in the engine cavity，including an increment state and a quasi-steady state. Moreover，temperature variation magnitude was affected by distances between the detectors and the fuel pools. Fuel-pool fire flame propagation inclined to the left side of the fan cavity，causing an increment of fire temperature on the left side. Plume floating，flame fusion，fusion expansion，and full flame coalescences were observed in the axial direction of the cavity.

To investigate the safety and stability of a proposed substation site in Pingdingshan city，Henan province，and avoid potential risks to the substation caused by the subsidence or tilting of the coal mine goaf，PS-InSAR was utilized to study 45 scenes Sentinel-1A data in Pingdingshan City from 2015 to 2022. A comprehensive analysis of the temporal deformation patterns of nine representative positions of the proposed site was performed. An evaluation mechanism for the safety and stability of the surface site of the coal mine goaf was established based on InSAR monitoring，and the evaluation of the site's safety and stability was completed. The research results demonstrate that the proposed fuzzy PS point selection method based on fuzzy sets theory can overcome the disadvantages of low PS point density，effectively increase the available data for analysis，and enhance the accuracy of monitoring results. After correcting the time series deformation of the representative points in the proposed area based on the reference point，it is found that the overall deformation of the proposed site is small and gradually showing a stable trend，with the maximum settlement of 13.05 mm，the maximum settlement velocity of 5.73 mm/a，and the maximum inclination of 0.070 mm/m. The analysis based on the safety and stability evaluation mechanism reveals that the surface displacement of the coal mine goaf is in a stable state，the substation foundation is in a safe state，and the surface settlement has little influence on the proposed substation. Based on the analysis of three evaluation indicators，the safety and stability level of the ground site on the coal mine goaf is classified as high，and it is feasible to build a substation.

In order to recognize the explosion suppression ability of potassium-containing fine water mist in the scenario of gas leakage in urban comprehensive pipeline corridors，the explosion suppression tests were carried out with additive-containing fine water mist located outside the methane-air explosion area by a self-made explosion experimental system. The effects of pure water and fine water mist of three potassium compounds，namely potassium oxalate，potassium carbonate and potassium chloride，on the overpressure and overfire range of 9.5% methane-air explosion were analyzed. The results indicate that the critical explosion suppression atomization concentration range of pure water mist outside the methane-air premixed area is 320-480g/m³. The overpressure decrease rate under potassium oxalate-containing conditions showed a trend of NormalCDF (Normal Cumulative Distribution Function) with increasing mass concentration，and the optimum suppression concentration is 10%. When the atomization concentration is 480 g/m ³，D₃₂ is 61.7 μm，the mass concentration of the compound is 10%，and the explosion suppression ability of water mist containing additives is greater than that of pure water mist. Among them，potassium oxalate has the strongest explosion suppression ability，followed by potassium carbonate and potassium chloride. The peak overpressure reduction rate is 2.32 times，1.88 times，and 1.53 times higher than that under pure water mist conditions，respectively. The range of overfire is reduced by 46.7%，40%，and 13.3%，respectively. Compared to potassium carbonate and potassium chloride，the potassium oxalate fine water mist outside the premixed area could absorb more heat and consume more active free radicals.

Aiming at the problem of large deformation and failure of soft rock roadway in deep coal seam roof，taking the belt transport roadway in No.Wu2 mining area of No.3 horizontal plane in No.6 Mine of Pingdingshan Coal Group as the engineering background，the failure mechanism and control countermeasures of surrounding rock in intercalated coal seam roadway were studied. Firstly，the combined arch mechanical model of the original scheme of belt was constructed，and the stability discriminant of the straight wall semi-circular arch roadway was derived. Secondly，the joint repair technology of "anchor cable-beam-grouting-composite mortar anchor cable" was proposed，that was，the roadway was expanded along the roof of No.Wu8 coal seam，and the basic support of the roadway was completed by anchor cable and ladder beam. The deep and shallow hole grouting of surrounding rock was used for reinforcement support，and the composite mortar anchor cables were arranged at the key parts of the roof and the two sides to strengthen the roadway support. The distribution characteristics of stress and displacement field before and after roadway repair were analyzed by numerical simulation. Finally，the industrial test of the roadway was carried out. The monitoring results of mine pressure show that the maximum convergence of the two sides and the roof and floor are 93 mm and 112 mm respectively，and the deformation rate of the surrounding rock of the roadway is less than 1 mm/d in the later stage. The deformation has been effectively controlled and the repairing effect is good.

In order to prevent the leakage failure of submarine pipelines，a FDHHFLTS-BN risk analysis method based on FDHHFLTS and BN was proposed to study the probability and key factors of the leakage failure of submarine pipelines. BN was transformed from the fault tree model，and then experts evaluated the probability of basic events according to FDHHFLTS. The best-worst method (BWM) was used to determine the weights of experts，and SAM was used to aggregate the opinions of experts. Finally，based on the constructed Bayesian network model，the probability of accident occurrence was obtained through forward reasoning. Also，the posterior probability was obtained through backward reasoning，and sensitivity was analyzed. Applying the method for the example analysis，the results show that the probability value of the leakage accident of the analyzed submarine pipeline is P=6.20×10^-3. Through sensitivity analysis，construction defect of weld-seam，construction defect of material，and fishing gear interaction can be identified as the key factors for the accident.

In order to judge the stability of the surrounding rock in a tunnel under the blasting vibration and damage，the mechanics model was established according to the instability characteristics of the layered surrounding rock. Considering the blasting damage and vibration effect，the total potential energy equation and catastrophe instability criterion were established，and the stability evolution law of tunnel under blasting was analyzed. Taking Yaojia tunnel in Hunan of Shanghai-Kunming high-speed railway as an engineering background，the stability of the layered surrounding rock in the tunnel was analyzed. The results show that the necessary and sufficient condition for the catastrophe instability of layered surrounding rock in the tunnel satisfies the bifurcation equation，that is，when the mutation eigenvalue Δ≤0，the system may suffer catastrophe instability. The cumulative effect of blasting results in the continuous reduction of surrounding rock stiffness，and the increase of blasting charge aggravates the blasting vibration effect，both of which increase instability probability for stratified surrounding rock. The actual instability evaluation results are consistent with the construction site situation and monitoring results，which verifies the effectiveness of the instability criterion.