In order to improve the systematicity and objectivity of safety risk identification in civil aviation ATC operations and to explore the causes and interaction relationships of ATC unsafe incidents, a causal analysis method for ATC unsafe incidents was proposed, integrating TM, HFACS, and FRAM. Firstly, TM technology was employed to perform text processing on unsafe incident reports, and high-frequency keywords related to ATC operation risks were extracted using the Term Frequency-Inverse Document Frequency (TF-IDF) method. Secondly, semantic attribution was conducted on these keywords, and an improved multi-level HFACS framework for ATC operations was constructed based on the characteristics of ATC work, and the corresponding risk factors were determined. Then, the interdependent relationships between various functional modules in the ATC operation system were analyzed by introducing FRAM to reveal the potential impact of interactions within the complex ATC system on incident occurrence. Finally, two cases of ATC unsafe incidents were investigated to analyze their risk causes. The results show that the proposed method effectively mines the interrelationships between multi-source causes and identifies multi-level risk causal factors, which verifies the effectiveness and scientific rigor of the method in multi-source data processing and complex causal structure mining.

To prevent the risk of abnormal gas emissions during tunnel excavation through unstable coal-bearing strata, this study focused on the inclined shaft section of Baoanying No.1 Tunnel in the Chengdu-Kunming Railway Expansion Project. Through on-site monitoring, numerical simulation, and engineering application, gas emission patterns, risk identification methods, and prevention technologies were investigated. The results indicate that tunnel gas originates from unstable coal seams and carbonaceous rocks within the strata, and gas emissions correlate strongly with coal/carbon content in surrounding rocks and the degree of geological fracturing. Then an integrated geophysical-geological drilling approach was employed to establish an advanced identification method for abnormal gas emissions. This method utilizes multiple indicators: unfavorable geological bodies, lithological variations, borehole gas concentrations, and emission rates. A "borehole curtain" interception technique was developed for high-efficiency gas risk prevention and control. Boreholes arranged in curtain patterns were drilled from both side chambers to intercept and extract coal-rock gas ahead of the advancing tunnel face. Field applications demonstrate that this technology reduces construction interference and increases advance rates.

To address problems such as fixed granularity in emergency scenario modelling and unclear descriptions of multi-scenario attributes and structures, a top-down unitary-scenario construction method was proposed from a microscopic perspective based on baseline thinking. Evolution relationships were established based on two types of knowledge elements, namely state elements and trigger elements. Combined with a hierarchical PN and refined layer by layer, the cascading evolution scenarios of emergencies were systematically characterized, and the evolution dynamics of scenarios were simulated. Taking cascading lifeline disaster events under heavy rainfall as an example, a hierarchical scenario model was constructed.. The characteristics of cascading failure, common cause failure and escalation failure features were characterized, and the evolution trends were analyzed. The interlocking dilemma between urban lifeline failure and emergency response was identified. The results indicate that the proposed scenario construction method can meet different levels of decision-making needs through a hierarchical scenario structure. The isomorphic Markov chain can identify the critical elements affecting the scenario evolution.

In order to address the challenges associated with the long-distance vertical transport of fire suppressant agents delivered by tethered firefighting drones in super high-rise building fires, a vertical transport model for foam extinguishing agents was established. The simulation results were comparatively validated against both empirical model calculations and experimental data. Furthermore, the study conducted an in-depth investigation into the effects of flow rate, gas-liquid ratio, and pipe diameter on pressure loss and flow velocity during the vertical transport of foam extinguishing agents. The findings indicate that the numerical simulation errors remain stable and are consistently less than 3%, demonstrating superior accuracy compared to the empirical model. In terms of flow characteristics, as the flow rate increases, pressure loss gradually rises, with the rate of increase becoming more pronounced at higher flow rates; concurrently, the stabilization time of the flow velocity within the pipe is reduced. Under constant flow rate conditions, when the pipe diameters are 60 mm and 100 mm, respectively, pressure loss decreases with an increase in the gas-liquid ratio. Moreover, increasing the pipe diameter mitigates the influence of the gas-liquid ratio on both frictional pressure drop and flow velocity. The impact of pipe diameter on pressure loss is primarily realized through alterations in the internal flow velocity: as the pipe diameter increases, the flow velocity decreases, leading to a corresponding reduction in frictional pressure drop. Within the pipe diameter range of 40 mm to 60 mm, the effect of pipe diameter on pressure loss and velocity variation is significant; however, when the pipe diameter exceeds 80 mm, this influence gradually diminishes. The research outcomes provide theoretical guidance for the vertical.

To investigate the influence of pre-existing fissures on the settlement and deformation behavior of high-fill compacted loess foundations, geotechnical centrifuge model tests were conducted for a flat-terrain high-fill engineering scenario. Two foundation models, an intact model and a fissured model, were designed and comparatively examined during the loading process with respect to deformation development and failure characteristics. The results show that the failure mode is transformed by fissures from a single tensile-cracking pattern to a combined tensile-shear failure, in which fissure propagation, a branched crack network, and stepped surface dislocation are formed. The overall stiffness and stability of the foundation are reduced by fissures; settlement is initiated earlier than in the intact model, the total settlement is increased, and the settlement distribution is more non-uniform. A V-shaped concentration pattern of surface settlement is exhibited and is markedly intensified with increasing load. In addition, a distinct stratified effect on stress distribution is induced by the fissure structure: vertical stress is concentrated in the upper layer, weakened in the middle layer, and only slightly affected in the lower layer, whereas horizontal stress is concentrated near the bottom and released in the middle and upper layers. These changes reconstruct stress-transfer paths and increase the risk of local instability.

In order to promote the implementation of the responsibilities of participating entities in the prevention and handling of mine safety accidents, improve the efficiency of safety governance and reduce the risk of mine safety accidents, the assumption of an enterprises' illegal liability was analyzed. The authority and responsibility system of regulatory authorities was sort out. The guarantee mechanisms for the professionalism and objectivity of work safety social service institutions were explored. Drawing on the provisions and practical experience of foreign jurisdictions regarding the primary responsibilities for work safety, and putting forward legal suggestions for improving the prevention and handling of mine safety accidents in China. The findings show that the addition of punitive damages and differentiated penalties for repeated illegal acts are important factors for enterprises to consider the costs and liabilities of illegal acts, which can raise enterprises' awareness of the importance of wore safety and firmly establish their sense of responsibility for work safety. Allocating the responsibilities of regulatory authorities by stages and constructing a regulatory model that attaches equal importance to inspections and unannounced investigations can straighten out the predicament of unclear division of powers and responsibilities of regulatory authorities and improve regulatory efficiency. Refining the access threshold for work safety social service institutions, establishing an information disclosure platform, and clarifying the provisions on accountability and the practice withdrawal system can ensure the professionalism, transparency and objectivity of the services provided by work safety social service institutions.

To prevent the occurrence of the butterfly effect in risk management, and in response to the scientific need to enhance the effectiveness of resilience governance in the face of risk amplification, a binary explanation framework for the butterfly effect was constructed based on the duality of risk. This framework encompassed social and cascading amplification of risk, clarifying the social amplification mechanism and cascading transmission pattern of the butterfly effect. On this basis, human-centered resilience construction mechanism in response to the butterfly effect was further explored. The results show that the duality of risk emphasizes the dialectical unity between the objective reality of risk its social constructiveness. Meanwhile, based on this duality, the uncertainty arising from the butterfly effect can be deconstructed, rooted in the complexity of modern socio-technical systems and the ambiguity resulting from the social construction of risk. On the one hand, modern socio-technical risks are interlinked and interdependent, forming an intricate risk network that exhibits endogenous complexity and provides impetus for risk cascade amplification. On the other hand, constrained by risk knowledge, the public's risk perception and behavior are influenced by social, institutional, and cultural factors, among others, manifesting as social ambiguity that creates conditions for the social amplification of risk. The duality of risk necessitates the establishment of a human-centered resilience governance system, that focus on improving risk monitoring and early warning system, refining risk communication mechanism, and promoting multi-stakeholder participation in governance, thereby enhancing the effectiveness of resilience management against the butterfly effect.

In order to accurately predict the noise distribution of offshore platforms to prevent occupational noise hazards, a joint simulation method combining the sound ray method and SEA method was proposed to solve the problem that the traditional single noise prediction method was difficult to take into account the structural sound and air sound propagation characteristics and could not describe the large-scale spatial sound field distribution in detail. In this method, SEA was used to simulate the acoustic propagation characteristics of the structure, and the acoustic propagation law of the air in the large space of the deck was simulated by the sound ray method. Taking an offshore central platform as the research object, a joint simulation model was constructed based on the measured vibration and noise source intensity data. The sound field distribution of each deck was simulated and calculated, and the effectiveness of the method was verified by a spatial grid noise test. The results show that the contribution of air acoustic energy to the total noise energy of each deck of the offshore platform is more than 50 %, which is higher than that of structural acoustic energy. Obstacles such as large-scale equipment, production area rooms and firewalls have a significant effect on noise shielding, and air sound propagation has a more prominent impact on the spatial sound field distribution of the deck, the joint simulation results are in good agreement with the measured results, and the overall average difference between the prediction and the test data is within 2 dB, which can realize the high-precision prediction of the spatial sound field distribution of the offshore platform deck.

To address the unsustainable problems arising from significant demand gaps, inadequate support, and delayed supply of emergency resources in major disasters, and to tackle the limitation of traditional evaluation indicators that overlook social and environmental sustainability, this study was conducted. Firstly, based on the triple bottom line theory of sustainable development and literature mining method, a comprehensive evaluation index system was constructed from three dimensions: economic support capacity, social support capacity, and environmental support capacity for emergency resource support. Then, the original indicators were revised through expert evaluation to determine the final selected indicators. Finally, the grey relational analysis method was applied to construct an evaluation model for emergency resource support capacity in major disasters oriented towards sustainable development. Taking Henan Province as an example, the model was applied to verify its scientificity and effectiveness. The research shows that, when considering various factors such as economy, society, and environment, the correlation degree of social support is 0.933 90, having the strongest impact on emergency resource support capacity. In addition, indicators such as fixed assets investment in the logistics industry, the number of social organization units, the number of hospital beds in medical and health institutions, and regional GDP rank among the top, making them key influencing factors driving emergency resource support in Henan Province.

In order to effectively identify the unsafe behaviors of construction workers in high-altitude environments, a recognition model based on MCT-GCN was proposed. Firstly, a data preprocessing module was designed to convert video surveillance data into three-dimensional skeleton data. Secondly, a tri-component dynamic adjacency graph convolution was constructed. It integrated learnable structural prior topology, channel correlation adaptive topology, and relative position encoding topology to dynamically build adjacency matrices adapted to different actions. Furthermore, a multi-scale separable temporal convolution was proposed to decompose standard convolutions into deep temporal convolution and point-by-point convolution, thereby independently modeling the temporal characteristics and spatial distribution characteristics of construction workers' actions. Finally, experimental verification and comparative analysis were conducted on both public datasets and a self-built dataset of workers' unsafe behaviors. The results demonstrate that the proposed model outperforms existing methods in terms of recognition accuracy and cross-scene generalization. On the self-built dataset, the model achieved a peak recognition accuracy of 95.8%, significantly enhancing the detection of workers' unsafe behaviors in complex and dynamic construction environments, and making a significant contribution to the development of intelligent monitoring and control in the construction industry.