Table of Content

28 January 2024, Volume 34 Issue 1

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Safety science theory and safety system science Safety social science and safety management Safety engineering technology Public safety

Safety science theory and safety system science

Research on disciplinary theory of saferesourcesology

WU Chao, WANG Bing

2024, 34(1):  1-9.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0475

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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.

Implementation path for cultivating public health emergency management talents under overall safety and emergency response

WANG Sitong, LONG Xuecheng, LIU Wei

2024, 34(1):  10-16.  doi:10.16265/j.cnki.issn1003-3033.2024.01.1364

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To adapt to the needs of public health emergency management and the changing talent requirements in the context of overall safety and emergency response, it is necessary to make appropriate adjustments to the public health emergency management talent development system. Firstly, the deficiencies and demands in cultivating public health emergency management talents were analysed. On this basis, the core elements in this training were clarified, including goals, types, modes, and curriculum development. Finally, the implementation path for cultivating these talents within the overall safety and emergency response was proposed. The results indicate the importance of updating educational concepts, implementing practical, experimental, and case-based teaching, integrating interdisciplinary training, enhancing collaborative and comprehensive skills, establishing a scientific evaluation system, and refining practical assessment methods to effectively enhance the construction of the public health emergency management talent development system.

Study on multi-level edge intelligent management and control mode based on SI-SB system safety model

ZHANG Chong, ZHANG Wei, LI Zeya, ZHAO Tingsheng, ZHANG Yaoting

2024, 34(1):  17-26.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0405

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In order to explore the innovative work safety control model empowered by information technology and intelligent technology, this study analyzed the characteristics of information flow in the safety control process from a perspective of safety informatics, and proposed a multi-level edge intelligent management and control mode. Based on SI-SB system safety model, the principles of safety decision lag and deviation in the safety management and control process were analyzed, and the idea of improving the performance of safety management and control system was proposed. Combined with the characteristics of safety organization management systems and the advantages of digital technologies, the foundation of digital technologies in enabling information perception and transmission, safety information interpretation, and safety behavior guidance was analyzed. And the pathways of digital technology in enabling digital perception, intelligent decision-making and multi-level control were analyzed. On this basis, the multi-level edge intelligent management and control mode for work safety with intelligence, agility, flexibility, and unity was proposed. Finally, the performances of responding with safety events were calculated and compared before and after the application of the digital control mode in the three types of scenarios: emergency, short-cycle control and long-cycle control. The results show that the proposed multi-level edge intelligent management and control mode can significantly improve the effectiveness of safety control.

Comparative study on definition of cause factors between 24Model and LCM

YUAN Chenhui, FU Gui, WU Zhirong, ZHAO Jinkun

2024, 34(1):  27-34.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0195

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In order to explore the similarities and differences, advantages and disadvantages between the definition of cause factors in LCM and the 24Model, a review of the definition of causes and results at various levels for both models was conducted. The definition content and its guidance role in safety practices, focusing on accident causation analysis, were compared. An empirical analysis was conducted using a coal mine gas explosion accident as an example to identify differences in the analysis results between the two models. The research shows that LCM is the first one-dimensional event sequence model that incorporates management factors into accident causation analysis. It provides clear definitions of cause factors at various levels and their logical relationships. However, LCM has issues with overlapping and repetitive definitions of causal factors and fails to reveal deeper accident cause factors such as guiding principles for safety work. 24Model, as a systematic accident causation model, predominantly defines various factors in terms of the organization. It describes the concepts of events, accidents, and safety, categorizing individual safety acts, safety capabilities, and organizational safety management systems, providing meanings and explanations. It explores organizational safety culture and reflects it with 32 elements. Both models' accident causation analysis methods are built on the definitions of cause factors at different levels and are applicable to their respective theoretical frameworks.

Studies on research objects of safety science

LI Xiao, FU Gui

2024, 34(1):  35-42.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0124

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In order to explore the appropriate research object of safety science from a perspective of practice, based on the methods of logical analysis and deductive reasoning, six criteria were constructed to evaluate the research object of the discipline. And on the basis of analysing the presuppositions, advantages and disadvantages of 11 main views, it was argued that accident is the appropriate research object of safety science from the perspective of practice. The results show that the research object in practice should have the characteristics of uniqueness, clarity, generalization, comprehensiveness, maturity and deducibility. The main views can not meet these characteristics of the research object that should be met in practice. The proposal of a clear definition of accident solves the demand for the concept of general safety. The essential problem of safety science is accident prevention.

Safety social science and safety management

Contagion mechanism of unsafe behavior information in groups of construction workers

NI Guodong, YANG Li, AN Yaoyao, ZHENG Yuzhuo

2024, 34(1):  43-52.  doi:10.16265/j.cnki.issn1003-3033.2024.01.2491

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In order to explore the contagion mechanism and effect of unsafe behavior information in groups of construction workers, a theoretical model of the contagion mechanism of unsafe behavior information among construction workers was constructed based on social information processing theory, theory of planned behavior, and social contagion theory. In this model, information about workmates' unsafe behaviors was served as the independent variable, and behavioral cognitive factors (i.e. behavioral attitudes, subjective norms, and perceived behavioral control) and unsafe behavioral intentions were served as mediating variables. Through developing measurement scales and creating questionnaires to collect data, the theoretical model was empirically tested based on 271 valid samples using the analysis methods of confirmatory factor analysis and structural equation modeling. The results show that workmates' intentional unsafe behaviors and workmates' unsafe communication behaviors can induce new unsafe behaviors through six contagious pathways. Moreover, as a source of contagion, the contagion effect of workmates' intentional unsafe behaviors is greater than that of workmates' unsafe communication behaviors. Managers can effectively control the contagion effect of unsafe behavior information among construction workers by controlling contagion information sources and weakening infectious media.

Intelligent modeling and simulation of online public opinion for major accidents based on proactive safety

CHEN Xin, XIE Kefan

2024, 34(1):  53-61.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0741

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In case of major security accidents, information disseminated wantonly and difficult to discern in terms of authenticity can easily cause negative social sentiments. This poses several issues to emergency rescue. Sentiment analysis, topic calculation, and the SEIR model were used to investigate online opinion simulation and control strategies for major security accidents. The CDBN-TCN-CRF sentiment analysis model was proposed by coupling the Convolutional Deep Belief Networks (CDBN), temporal convolutional networks (TCN), and conditional random fields (CRF). Then, the T-distributed Wasserstein autoencoder (TWAE) topic computation model was used to discern sentiment polarity, topic categories, race sentiment trajectory, and public attention focal points within the network discourse. Furthermore, the proposed SEIR model was used to predict online public opinion tendency and analyze the dissemination dynamics and their influencing factors. The results indicate that the coupling of CDBN-TCN-CRF sentiment analysis, TWAE topic computation, and SEIR model has a better prediction performance on network discourse analysis and trend analysis.

Promotion path of civil aviation employees' willingness to share safety information: based on fsQCA

ZHENG Xiumei, MA Guoyu

2024, 34(1):  62-69.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0162

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In order to explore the promotion path of civil aviation employees' willingness to share safety information, a multi-condition linkage model was constructed based on the theory of Person-Environment Fit, which presented the impact of individual characteristics and organizational environment on employees' willingness to share safety information. On the basis, model validation was carried out using fsQCA method based on 178 survey questionnaires. The results show that willingness to share safety information is not driven by a single condition, such as individual cognition level, job embeddedness, professional identity, leadership support, and safety culture, but rather the result of multiple conditions. There are three models for promoting higher levels of willingness to share safety information. The first is employee autonomy-driven model, which has as its core conditions high individual cognitive, high job embeddedness, and high professional identity. The second is the resonance-driven model, the core conditions of which are high individual cognitive, high professional identity, high support from leaders, and insufficient job embeddedness. The third is the leadership support-driven model, whose core conditions are high support from leaders and the absence of safety culture.

Influences of distracted behaviors on driving performance of drivers in city

LUO Shuang, YI Xinxin, SHAO Yiming, XU Jin

2024, 34(1):  70-76.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0175

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To investigate influences of common distracted driving behaviors on driving performance in the urban environment, three secondary tasks were designed. Sixteen young subjects were recruited. The driving tests were conducted under real conditions. Vehicle longitudinal and lateral driving parameters were measured. The driving performances under normal driving and distracted driving conditions were compared and analyzed, and the influences of driving age on these performances were also discussed. The results show that compared to the normal driving, in all 3 distracted conditions, the standard deviation of longitudinal acceleration and the standard deviation of lateral acceleration increase while vehicle speed decreases. This indicates that drivers compensate for driving performance by speed and maneuver while distracted. The mean speed and the mean longitudinal acceleration are significantly influenced by the talking task, while the standard deviation of speed and the mean lateral acceleration are significantly influenced by reading the advertisement (p<0.05). The standard deviation of speed is significantly higher for experienced drivers compared to novices in the phoning condition (p=0.021). During phoning and advertisement reading tasks, the mean lateral acceleration is significantly higher for experienced drivers compared to novices (p=0.003, p=0.004). This means the experienced drivers are less affected by distracting behaviors.

Safety engineering technology

Visual load in threshold zone of highway tunnel based on Topsis improved factor analysis method

LIANG Bo, QIN Can, NIU Jia'an, XIAO Jinghang, WEN Sen

2024, 34(1):  77-84.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0039

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In order to investigate the visual load of drivers at the threshold zone of linear highway tunnels, five visual indicators of drivers were collected through the real vehicle test. A visual load evaluation model was developed by the Topsis improved factor analysis method, the visual load at different times and locations was analyzed, the evaluation criteria of driving comfort were proposed based on the constructed visual load curve, the generalization ability of the constructed load model was verified by using published data, and finally, the influence of visual indicators on visual load was investigated by sensitivity analysis. The results show that when the driver locates about -13 m to 55 m (12:00) and -10 m to 49 m (15:00) from the entrance, the visual load exceeds the boundary value (0.906), indicating the driver's driving comfort and safety is extremely low. The visual load and closeness of the drivers near the entrance are much greater than those inside and outside the entrance, and the visual load and closeness at 18:00 are much lower than those at 12:00 and 15:00. The sensitivity parameters of the visual indicators are fixation duration, pupil area, fixation time, saccade range, saccade speed in descending order.

Research progress on prevention and control of mine earthquake and rock burst

LI Junping, GUAN Tingting, FENG Jiayu, WANG Haiquan

2024, 34(1):  85-93.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0103

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Mine tremors and rock bursts are hot, difficult, and bottleneck problems that need to be solved urgently in the mining field. In order to effectively control mine tremors and rock bursts, the definition and classification of mine tremors, the hypothesis of mine pressure and the prevention and control technologies of mine tremors and rock bursts were summarized. And the theory of roof-cutting and pressure-relief was reviewed. Then, its application in abandoned stope disposal and pressure unloading mining of medium-thick gold mines and gob-side entry retaining laneway of medium-thick and below coal mines were introduced, and its difference with 110 working method was compared. Based on this, the definition of mine tremors was given, and it was pointed out that the occurrence conditions of mine tremors are similar to those of rock bursts. Therefore, the controlled blasting and groove caving technology of a deep-buried hard roof plate was put forward for thick ore body mining. The summary shows that the technology of controlled blasting groove caving is still the main method to release and transfer high underground pressure in the prevention and control of mine tremors and rock bursts in the future, it can also simplify the "masonry beam" of deep-buried thick orebody into a spring rock beam bearing system.

Investigation of adsorption characteristics of C₂H₄ from coal in low-temperature stage

WEN Hu, LI Zhuofeng, ZHANG Duo, TANG Rui, LI Jie

2024, 34(1):  94-105.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0299

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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.

Study on slipstream characteristics of 400 km/h high-speed trains passing through tunnels

XIONG Xiaohui, ZHANG Duoduo, GENG Yutang, YANG Bo, TANG Mingzan, CHEN Guang

2024, 34(1):  106-115.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0435

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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.

Aircraft taxiing trajectory prediction and conflict risk identification in airfield area based on AM-LSTM

WANG Xinglong, XU Yanfeng

2024, 34(1):  116-124.  doi:10.16265/j.cnki.issn1003-3033.2024.01.1517

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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.

Correlation analysis and prediction of coal spontaneous combustion risk based on correlation coefficient method

ZHANG Yutao, GUO Qiang, ZHANG Yuanbo, LI Yaqing, SUN Yali

2024, 34(1):  125-132.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0774

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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.

Temperature variation characteristics of double fuel-pool fire in fan cavity based on software FDS

CHENG Guanbing, YE Haohui

2024, 34(1):  133-139.  doi:10.16265/j.cnki.issn1003-3033.2024.01.1803

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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.

InSAR deformation monitoring and safety and stability evaluation on surface of coal mine goaf

DONG Jianjun, ZHANG Ying, LI Xin, MEI Yuan

2024, 34(1):  140-149.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0148

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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.

Study on explosion suppression characteristics of water mist containing potassium compounds outside methane-air premixed area

WANG Xiaoling, LIU Zhenqi

2024, 34(1):  150-157.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0695

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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.

Deformation and failure analysis and control of deep roadway with intercalated coal seam in roof

YUAN Yue, ZHANG Fengbin, SHANG Xi, LIU Zhaoqiang, PENG Gang

2024, 34(1):  158-165.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0806

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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.

Quantitative risk analysis on failure of submarine pipeline leakage based on FDHHFLTS-BN

LIU Fupeng, YANG Jiu, WU Shibo, XU Lixin

2024, 34(1):  166-170.  doi:10.16265/j.cnki.issn1003-3033.2024.01.1247

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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.

Study on catastrophe instability criterion of layered surrounding rock in tunnel under blasting

PENG Yaxiong, ZHOU Zipei, YAO Yingkang, LIU Yunsi, ZUO Qingjun

2024, 34(1):  171-178.  doi:10.16265/j.cnki.issn1003-3033.2024.01.2440

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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.

Study on flame image recognition of chemical industrial park fires based on convolutional neural network

ZHANG Shulin, ZHANG Ya'nan, TIAN Chao, YAN Xiang, LU Yi, SHI Shiliang

2024, 34(1):  179-186.  doi:10.16265/j.cnki.issn1003-3033.2024.01.2333

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In order to discover fire accidents in chemical industrial parks in time and reduce accident losses, this study used CNN to establish a real-time fire detection system for chemical industrial parks. Based on CNN, the YOLOv5 algorithm was used to calculate chemical industrial park fire data sets and ordinary fire data sets. The loss value, recall rate, precision and mean average precision of the two data sets were compared. Among them, the loss value and recall rate of the chemical industrial park fire data set are slightly lower, but the precision and mean average precision were higher than that of an ordinary fire data set, which shows the feasibility of detecting fire. In addition, based on fire detection results, this study further designed the flame image recognition software system for the chemical industry park with the help of the PyQt5 program framework, realized the application of fire image and video recognition in the chemical park, and expanded the application scope of the method. The results show that the YOLOv5 target detection algorithm based on convolutional neural network can detect fires in chemical industrial parks in real-time. This detection method is portable,and the results are reliable, which can help improving the safety management level of the chemical industrial park.

Research on deformation characteristics and driving safety of upper arch of ballastless track in tunnel

SONG Huilai, LIN Jinzhen, JIANG Dianyou, ZHANG Lushun, YU Lei

2024, 34(1):  187-192.  doi:10.16265/j.cnki.issn1003-3033.2024.01.2363

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To evaluate the influence of upper arch deformation on the safety of train operation on ballastless track inside high-speed railway tunnels, the upper arch deformation characteristics of different ballastless tracks were obtained based on measured data. Subsequently, a dynamic calculation model of the coupled system of uplift arch filler layer-ballastless track-vehicle was established. The impact of different upper arch deformation characteristics on the dynamic response of the vehicle was determined by using the calculation model, thereby assessing the safety of high-speed train operation. The results show that the measured wavelength is mainly distributed in 3 to 30 m and the amplitude is mainly distributed in 0 to 8 mm, among which the upper arch deformation is the most prominent with a wavelength of 10 m and an amplitude of 2 mm. When the upper arch wavelength is less than 6 m, the peak value of wheel-rail force is larger, and when the upper arch wavelength is about 12 m, the peak value of vertical acceleration of the vehicle is larger. The upper arch, with a wavelength of about 6 m, has a significant impact on high-speed driving safety and has a certain derailment risk, which should be paid more attention.

Heterogeneous vehicle routing problem of hazardous materials transportation considering carbon emissions

MA Tianming, HUANG Chuyuan, CHEN Xianfeng

2024, 34(1):  193-199.  doi:10.16265/j.cnki.issn1003-3033.2024.01.1243

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To fill the research gap, a HVRP for hazardous materials transportation was proposed in this study, aiming at optimizing the three objectives as total risk, total cost and total carbon emissions. Firstly, in the model construction stage, the measurement methods of total cost and total risk were improved, including establishing a loading-dependent risk quantification method for explosion scenarios, and designing a specific soft time window for penalty cost calculation, which could preferentially reduce the waiting time of vehicles with large loads at customers. Then, to better solve the above model, the NSGA-II was improved in two aspects. A hybrid crossover method with new crossover operators was designed to improve the global search efficiency, and a two-stage variable neighborhood search (VNS) algorithm was adopted to improve the local search ability. Finally, a numerical example was given to verify the effectiveness of the model and algorithm. The results indicate that, compared with the original NSGA-II, the convergence curve of the improved algorithm decreases faster, and the average values of the three optimization objectives of total cost, total risk and total carbon emissions are further reduced by 3.36%, 12.16% and 6.96% respectively. In a fleet with limited number of vehicles, the carrier can have different degrees of influence on each target by choosing different vehicle types.

Ignition mechanism of high-voltage power cables under influence of internal heat source

WANG Tao, SONG Xiaofeng, XU Wenshu, AN Weiguang

2024, 34(1):  200-205.  doi:10.16265/j.cnki.issn1003-3033.2024.01.1133

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In order to explore the spontaneous combustion mechanism of high-voltage power cables under the effect of core heating when it was overloaded or short circuited, heating rods was used to simulate the internal heat source for experimental research. The influence of the power of the internal heat source and the cross-sectional area of the inner core of the cable on the key parameters of the spontaneous combustion characteristics, such as cable temperature rise and ignition time, were analyzed. It was found the whole process of cable from heating to ignition to combustion can be divided into four stages: initial heating, pyrolysis gas escaping, ignition, combustion and extinguishment. The results show that the dripping of insulating layer melt leads to the change of flame shape. The heating rate of the surface temperature of each structural layer of the cable increases with the increase of internal heat source power and the decrease of the distance to the surface of the internal heat source. The increase in the power weakens the influence of the cross-sectional area of the inner core of the cable on the heating rate of each layer. The ignition time of the cable is linearly decreasing with the power of the internal heat source.

Public safety

Research on smoke exhaust efficiency and evacuation of multi-storey terminal buildings under action of environmental wind

SONG Yang, MA Wenju

2024, 34(1):  206-214.  doi:10.16265/j.cnki.issn1003-3033.2024.01.1866

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In order to investigate the effect of smoke evacuation patterns under ambient winds on the safe evacuation of people, taking a terminal building as the subject of the study, the multi-floor area was selected as the data acquisition range, 33 control conditions were divided by controlling the smoke exhaust window, and fire dynamics simulator (FDS) software was used to obtain the smoke exhaust effect in the building under different conditions. Further construct wind direction intervals with north winds shifting to east winds via northeast winds to obtain the curve law of wind direction and time to reach hazards, and 0-90° as the high side window opening angle interval to obtain the suitable window opening range, according to the environmental wind to determine and optimize the safe evacuation. The results show that for the smoke exhaust effect in the building, if the high side windows are fully opened, it is conducive to smoke exhaust under no wind and low wind speed. If the wind speed is high, the wind direction perpendicular to the floor alignment is more effective for smoke evacuation. In the wind direction range, the wind direction of 0-70° will promote the smoke exhaust of the high side window, and the wind direction of 30 and 60° is the best, and the wind direction along the floor trend will have smoke backflow. Within the high side window opening angle, a 5-30° down-hung window or full opening window is appropriate. Combined with the time to reach hazards of the wind direction, the evacuation of floor personnel is optimized, and the evacuation time after adjustment is reduced by 10% compared with the unoptimized time.

Numerical simulation of gas explosion in underground unventilated kitchen based on FLACS

PENG Shanbi, LI Wei, TANG Ping

2024, 34(1):  215-222.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0275

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In order to optimize the anti-explosion design of an underground unventilated kitchen, the finite element model of a house with an underground unventilated kitchen was established in FLACS software. Based on this model, the effect of gas cloud size, ignition position, shape of obstacle, position, and size of obstacle on gas explosion pressure was investigated. The extent of explosion damage to the unventilated kitchen structure was obtained according to simulation results. The results show that when the gas cloud size increases in the unventilated kitchen, the explosion damage to the building is more severe. The maximum pressure peak values are 41.9, 19.5, and 3.25 kPa when ignition is in the kitchen, ventilation shaft, and living room. When an obstacle exists, a greater amount of pressure is generated. The peak pressure is much higher when the obstacle cross-section shape is square than when it is circular and rectangular. The closer the obstacle is to the ignition position, the more intense the pressure peak. With the increase in the obstacle section size, the peak pressure increases continuously. The greatest rise in peak pressure is near the elevator. Shock waves from gas explosions in unventilated kitchens have a greater impact on the floor space than in traditional kitchens.

Characteristics of urban public safety risk and its enlightenment for risk management

ZHANG Chao, WENG Wenguo, CHEN Yong, DAI Baoqian, QIN Tingxin

2024, 34(1):  223-230.  doi:10.16265/j.cnki.issn1003-3033.2024.01.0627

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In order to establish a scientific, accurate and normative urban safety risk management system, this paper makes some proposals based on the characteristics of urban safety risk. First, the urban safety risk was classified into four types according to the causal chain model which was established based on the definition and connotation of risk. Then, the characteristics of these four types of risk were analyzed considering the relevant static and dynamic urban characteristics. Last, the general and specific urban safety risk management proposals were made considering the current practice. This research shows that the characteristics of urban safety risk include accumulation of conventional risk, emergency of emerging risk, intensification of complex risk, and frequent occurrence of extreme risk. Some measures should be implemented to enhance the urban safety risk management system. The general framework of urban safety risk management should be established, and the specific risk assessment process and risk treatment measures should be implemented. Further, they should be integrated into the regular emergency management system of a city.

Public safety

Fire type discrimination of hazardous chemicals tanker based on multinomial Logistic

LIU Yong, LI Xiao, SHI Shiliang, LU Yi, WANG Zhengwu, SHI Xingyu

2024, 34(1):  231-237.  doi:10.16265/j.cnki.issn1003-3033.2024.01.1871

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In order to effectively prevent and control fire accidents of hazardous chemical tanks during transportation, it is necessary to identify the type of tank fire quickly and correctly. The statistical data of domestic hazardous chemicals tanker fire accidents from 2013 to 2020 was analyzed with Python software. According to the characteristics of fire accidents, a regression model with multiple logistic regression theory was established. The three common fire types of hazardous chemicals tankers, namely, jet fire, pool fire and BLEVE(Boiled Liquid Evaporate Vapor Explosion)fire, were regarded as the categories of explained variables. Through the analysis of accident data, a total of 15 fire factors in five aspects, namely, space and road characteristics, time and meteorological characteristics, personnel factors, vehicle and equipment factors, and hazardous chemicals factors, were determined. A multiple logistic regression equation of fire probability of hazardous chemicals tankers was constructed, and the explicitness and accuracy of the equation were tested. The determined model was proved by examples. The probability of three types of fire in hazardous chemicals tankers was obtained. The accident prevention measures were proposed. The results show that it is the most likely a pool fire for a liquefied natural gas tanker, with a probability of 0.55. The second one is jet fire, and the last one is the boiling liquid expanding vapor explosion fire. To reduce the probability of pool fires, measures such as improving the mechanical strength of the container and reducing the collision strength could be adopted to prevent leakage holes of large size in the container. Measures such as slowing down the leakage rate, controlling the leakage range and efficient scientific fire extinguishing are adopted to decrease sequences of tank fire.

Research status and prospect of fire origin determination based on fire traces

NIU Tianhui, GENG Dianqiao, YUAN Yi, ZHAO Liang, DONG Hui, WANG Bai

2024, 34(1):  238-246.  doi:10.16265/j.cnki.issn1003-3033.2024.01.2351

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In order to help fire investigators determine the location of the fire origin, improve the chain of evidence in accident investigations and identify the cause of the fire quickly and accurately, the researches on fire origin determination based on fire traces were reviewed in present paper. First, fire traces were classified, including burn marks, smoke marks, collapse marks and electrical wiring marks, with emphasis on soot deposition traces. Then, multiple fire origin determination methods at home and abroad were reviewed and classified into three categories: determining the fire origin directly using experience, determining the fire origin using numerical reconstruction techniques, and determining the fire origin using machine learning algorithms. The advantages and limitations of each method were analyzed respectively. Finally, the future research tendency of fire origin determination technology was prospected. The results show that numerical simulation of soot deposition traces combined with machine learning for fire origin determination has a good perspective for application.