In order to more effectively and accurately judge the gas concentration field，temperature field，and flow field distribution in the goaf during the mining of extra thick coal seams，and thereby determine the self-ignition risk area for layered mining of extra thick coal seams，taking the 172307 working face of Lingquan mine as an example，numerical simulation technology was used to establish a mathematical model of coal spontaneous combustion in the goaf for layered mining of extra thick coal seams based on the coupling mechanism of multiple fields in the goaf. Combined with the distribution models of coal oxygen consumption rate，heat release intensity，critical oxygen concentration for spontaneous combustion，porosity and permeability，the evolution law of the spontaneous combustion risk zone for layered mining of extra thick coal seams in a stable state was obtained through the simultaneous solution. The results show that in the upper layered goaf，the high oxygen concentration area and the high-temperature area are mainly located near the stop mining line and in the upper part of the intake and return air tunnels，and the main air leakage area is located at the stop mining line. In the composite goaf，the high oxygen concentration area is mainly located on the inlet and return air sides. As it moves towards the deeper part of the goaf，the oxygen concentration shows a decreasing trend. And a local high-temperature zone resembling an ellipse appears at a certain distance from the coal mining face.

To investigate the effects of different incidental emotions on low sensation seekers' unsafe behavior decision-making process from a neural level，ERPs technique was used. The Chinese version of the Sensation Seeking Questionnaire for College Students was used to select low and medium sensation seekers (control group). Then，video clips were used as emotional stimulus materials to induce positive and negative emotions before the experiment，and a risk scenario task was set to perform risk decision-making experiments. The results indicated that when the emotional stimulus variable was not considered，there was no significant difference in safe behavior decision-making between the low sensation-seeking and the control groups. Under positive emotion，low sensation seekers maintained risk aversion. However，low sensation seekers were more likely to make unsafe behavior decisions regarding behavioral performance under negative emotion. Under negative emotion，the latency of LPP induced by low sensation seekers was delayed，indicating that the interference of negative emotion made it more difficult for individuals to classify and evaluate risks. Therefore，the intrinsic reasons for their external behavioral performance can be explained from a neural level. Therefore，emotions play a moderating role in the process of sensation seeking affecting safe behavior decision-making.

To establish a comprehensive evaluation system for urban waterlogging risk，three dimensions were selected: water accumulation risk，overload risk，and lateral inflow. This system aims to provide a reference for the optimal placement of storage tanks. Firstly，a mixed MCDM framework including the improved analytic hierarchy process (IAHP)，anti-entropy weight method (AEW)，and technique for order preference by similarity to ideal solution (TOPSIS) was designed. Then，the IAHP-AEW-TOPSIS model was compared with IAHP-TOPSIS and AEW-TOPSIS model respectively，and the ranking consistency was verified by Spearman ranking correlation coefficient. The performance of IAHP-AEW-TOPSIS model was confirmed by calculating variation coefficient，relative range and sensitivity. Finally，a model based on MCDM-BPNN was established and verified by a waterlogging-prone area in Shanxi Province. The results show that water accumulation risk has the most significant influence in the evaluation system of urban waterlogging risk，with the weight of 0.46，followed by the overload risk with the weight of 0.36. The location of the node and the number of connecting pipes greatly affect the risk of waterlogging of the node，and waterlogging occurs more frequently at the junction of pipes or in larger confluence areas. There was better performance exhibited by the IAHP-AEW-TOPSIS model. In the 5-year and 10-year return periods，the accuracy of MCDM-BPNN model verification set is 93.3% and 100% respectively，which can accurately and rapidly simulate and predict urban floods. After the application case is set up，the number of high，medium and low risk nodes are 7，9，30 and 6，19，21 respectively，and the effect of reducing waterlogging overflow is remarkable.

To explore the influence of the lithology and cross-section shape on spalling failure properties of deep hard rock tunnels，indoor true triaxial tests on spalling failure were performed. Firstly，two types of rock samples (marble and granite) and two typical cross-section shapes (high side wall gate arch shape and horseshoe shape) samples in practical applications were selected. Then，the failure characteristics under the influence of different lithology and cross-section shapes were analyzed from the three aspects including spalling failure mode，spalling rock plate characteristics，and the characteristic stress during spalling. Finally，numerical simulation was conducted to explore the corresponding displacement and stress distribution characteristics during the development and propagation of the cracks. Furthermore，the spalling failure characteristics of deep hard rock tunnels were investigated. The results indicated that the slab peeling and opening failure phenomenon for the marble sample was more significant than the granite one in terms of spalling failure mode during the test process. Moreover，the cross-sectional contour range involved in spalling failure for the horseshoe shape sample was smaller than the high-side wall gate arch shape. Different lithologies presented different flaked rock slab shapes for different flaked rock slab characteristics. Compared with the high-side wall gate shape，the flaked rock slabs near the outer layer relevant to the curved wall arch sample were more slender. For the characteristic stress during spalling，the granite sample had a larger threshold at the beginning of the spalling and a faster rate for the evolution process of the spalling failure compared with the marble one. Furthermore，compared with the horseshoe shape sample，the characteristic stresses of the high-side wall gate arch sample were higher from the beginning of plate cracking to the occurrence of obvious plate cracking failure. The area with large displacement in the numerical simulation was mainly observed on the side wall of the hole. The farther away from the side wall，the smaller the displacement. Moreover，the major reason the spalling occurs can be attributed to the tangential stress concentration.

In order to ensure the normal operation of wastewater treatment plants and prevent equipment failures，an improved FMEA risk assessment model was proposed. Firstly，the FMEA method was used to identify the failure modes of wastewater treatment plant equipment，and it was combined with PFS to portray the uncertainty assessment information. Secondly，the subjective and objective weights were calculated using the stepwise weight assessment ratio analysis (SWARA) method and the maximum deviation method，and the comprehensive weights of the three risk factors were calculated through the game theory combination weights. Thirdly，the multi-objective optimization on basis of ratio analysis (MOORA) method was used for the equipment failure mode risk ranking. Finally，taking Changchun City Z wastewater treatment plant equipment failure risk assessment as an example，the model proposed in this paper was compared with traditional FMEA，Pythagorean fuzzy technique for order preference by similarity to ideal solution (PF-TOPSIS)，and Pythagorean fuzzy VlseKriterijumska Optimizacija I Kompromisno Resenje (PF-VIKOR)，and the feasibility and effectiveness of the model were verified. The results show that the top 3 failure modes of wastewater plant equipment are that the grit extracted by the grit remover contains excessive organic matter，the diaphragm is dislodged or broken，and large foreign objects enter the pump.

In order to prevent coal spontaneous combustion disasters under high-temperature environment and clarify the spontaneous combustion characteristics，coal samples from the 1306 working face of the VI coal seam in Barapukuria coal mine were selected. The coal samples were subjected to constant temperature treatment at 40，50，and 60 ℃ for 30 days，and pore structure analysis and thermogravimetry(TG) were performed on the raw coal samples and high-temperature pretreated coal samples to test the oxidation kinetic parameters. The results show that after high-temperature treatment，the proportion of small pores decreases while the proportion of medium pores and large pores increases. After treatment at 60 ℃，the specific surface area of the coal sample increases from 2.351 m²/g of raw coal to 3.285 m²/g，and the total pore volume increases from 0.007 88 mL/g of raw coal to 0.010 01 mL/g. In addition，compared with raw coal，the ignition temperature and burnout temperature of the coal sample significantly decreased after high-temperature treatment，and the maximum weight loss and the maximum weight loss rate increased by 6.1% and 23.3%，respectively. The calculation results of oxidation kinetics show that the activation energy and pre-exponential factor of the coal sample after high-temperature treatment are lower than those of the raw coal，indicating that the high-temperature environment significantly improves the oxidation reaction activity and increases the risk of spontaneous combustion of coal.

In order to prevent and control the explosion hazards of ethylene/polyethylene hybrid mixture，bicarbonate was selected as the explosion suppression powder，and the explosion suppression experiment was carried out in a 20 L spherical explosion device to explore the explosion inhibition effect and mechanism of different bicarbonate on ethylene/polyethylene hybrid mixture. The differences of explosion inhibition performance of different bicarbonate on the hybrid mixture were discussed. The results show that the hybrid mixture is more difficult to inhibit than the single-phase polyethylene. With the increase of ethylene concentration，the explosion inhibition of the hybrid mixture becomes more difficult. The bicarbonate has an inhibitory effect on the ethylene/polyethylene hybrid mixture with different concentrations，and the inhibition efficiency is affected by the concentration of ethylene and bicarbonate. Bicarbonate can inhibit the ethylene/polyethylene hybrid explosion through physicochemical reaction during the polyethylene explosion. The decomposition and endothermic properties of potassium bicarbonate and its retardation effect on polyethylene pyrolysis are better than those of sodium bicarbonate，so the inhibition effect of potassium bicarbonate on the explosion of ethylene/polyethylene hybrid mixture is better than that of sodium bicarbonate.

The aim of this study is to investigate the dispersion of aluminium powders with different SF in a 20 L spherical container. By establishing a numerical model describing the formation of a two-phase dispersion system of dust carried by a gas stream，including the equations of the gas flow and the trajectory of the dust particles，unsteady numerical simulations were carried out. The spatial distribution of dust，the turbulent kinetic energy and velocity at the center of the spherical chamber with time changes were analyzed under the conditions of SF of 0.2，0.4，0.6，0.8 and 1.0，respectively. The results show that the dispersion of airflow-carried dust inside the ball chamber can be divided into four stages，including powder intake，diffusion，stabilization and settling，and the dispersion uniformity and maximum velocity values are enhanced with the increase of SF. The bigger SF is，the closer the particle shape is to spherical，and the better the dispersion of aluminum dust is. The smaller SF is，the easier the dust will accumulate near the wall surface. When the nominal concentration is certain，SF ≤ 0.4，the peak concentration increases with the increase of SF，SF > 0.4，the peak concentration decreases with the increase of SF. The maximum value of the turbulent kinetic energy of the aluminum powder-air mixture decreases with increasing values of SF，the peak velocity of the aluminum powder particles increases with increasing values of SF.

In order to guarantee the structural safety of masonry structures in existing buildings and prolong their lifespan，a SHM system and the mean value control charts were employed to investigate the condition evaluation and early alarming mechanism of these structures. The monitoring items for this structure were chosen to be the load-bearing wall cracks and the relative displacement of window sills. The data about structural reaction and ambient temperature was collected，and a correlation model between these two factors was built. Additionally，the correlation model was employed to replicate the temperature impact of the data collected from monitoring the structural response. Ultimately，the structural condition index was suggested and integrated with the mean value control chart to assess the early detection of potential issues in the structure. The structural condition index represented the disparity between the simulated outcomes of the correlation model and the real measured values. The findings demonstrate that the system has the capability to gather real-time monitoring data，accurately assess structural health，and promptly alert about structural damage. The monitoring data indicate that the crack width varies between 0.746 and 4.391 mm，while the sill relative displacement spans from 1.282 to 5.690 mm. Both of these variations are within the acceptable safety limit. From the findings of the mean value control chart in the early alarming system，the fracture width and relative displacement of the window sill are within normal parameters.

To ensure the safe，high-quality，efficient，and environmentally friendly construction of future infrastructure projects，it is crucial to investigate the prevalent issues and characteristics of intelligent safety management and control practices in infrastructure projects. Firstly，the evolutionary process of intelligent safety management and control was comprehensively reviewed. It includes four distinct stages: intelligent identification and control of risk sources，data-driven identification and rectification of safety hazards，enhancement of intelligent safety management and control system，and comprehensive integration of intelligent management and control. On this basis，the successful experiences of different stages were summarized. Secondly，the challenges encountered in intelligent safety management and control were analyzed from the perspective of overall collaborative management，and its characteristics were analyzed from the perspective of "people，objects，environment，and management". Subsequently，starting from the three dimensions of safety management process，the whole life cycle of engineering construction，and the development level，the thoughts on intelligent management and control for infrastructure engineering safety were proposed，focusing on "reverence for safety，intelligent safety，inherent safety，digital intelligence，digital capability，and digital value". Finally，the future development path of intelligent safety management and control was envisioned. The results show that the safety management and control of infrastructure projects are transitioning from experience-based to data-driven approaches，while rapidly integrating new technologies，equipment，and processes. Intelligent safety management and control represents a significant extension of intelligent construction and management in infrastructure engineering. This is mainly evidenced by the transformation of safety management concepts，methods，and systems，as well as the value extraction from data assets. In the future，the intelligent management and control for infrastructure engineering safety will develop to comprehensive data fusion，knowledge-driven，virtual and real integration，human-machine collaboration，and full life-cycle control. At the same time，the importance of data privacy protection and standardised governance will become increasingly prominent.