Table of Content

28 December 2023, Volume 33 Issue 12

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Safety social science and safety management Safety engineering technology Public safety Technology and engineering of disaster prevention and mitigation Emergency technology and management Occupational health

Safety social science and safety management

Risk zoo (III): cognitive mechanisms and paths of risk metaphors based on animal imagery

TONG Ruipeng, HU Xiangyang, YUAN Jiacong, WANG Denghui

2023, 33(12):  1-7.  doi:10.16265/j.cnki.issn1003-3033.2023.12.1309

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In order to explore the cognitive construction mechanism and role path of animal imagery in risk metaphors and to excavate the correlation property between animal imagery and risk types, the connotation of risk attributes in animal imagery was analyzed under the perspective of cognitive science. The cognitive mechanism of animal imagery was analyzed in terms of cognitive construction, cognitive process and cognitive thinking. The effectiveness of risk metaphors was explored in terms of their effects and transmission paths. The results show that risk metaphors use animal imagery to characterize the existence of different types of risks, and convey the conceptual structure of risk events through the structural transformation from animal spatial images to animal schematic imagery. As an important medium for risk knowledge dissemination, the process of risk metaphor dissemination is the result of the interaction between cultural field, knowledge field and practice field. Individuals understand and accept risk metaphor information according to the "skill-rule-knowledge" structure, and their behaviors and attitudes are changed towards the expected goal, so as to achieve the expected effect of risk metaphor and expand the means of risk perception and risk communication.

Evolutionary game of construction safety supervision involved by work safety service provider

CHEN Shu, YIN Jia, SHAO Bo, CHEN Yun, WANG Yue

2023, 33(12):  8-15.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2163

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This study aims to improve the current situation of high incidence of accidents in the process of construction work safety. The possible rent-seeking phenomenon of introducing the intermediary services for work safety was analyzed. By applying the method of game theory, a 3-party evolutionary game model was established among construction enterprises, work safety service providers and government regulators. The evolutionary characteristics of the 3-party behaviors were analyzed, and the stability of the equilibrium point in the game system was simulated. The results show that the high cost of implementing safety management makes the construction enterprises and work safety service providers choose behavior strategies that are not conducive to the safety management of construction projects. Reasonable control of the maintenance and rectification costs and the safety management inputs enables them to actively implement safety management strategies. In the process of supervision, the government should focus on work safety service providers, strengthening the regulation of the providers' behaviour, and guide the construction enterprises to act in accordance with the rules, which is conductive to achieving the goal of regulating the behaviour of both sides while saving costs and inputs. Simulating the public to actively participate in the supervision of construction safety and increasing the rent-seeking costs of enterprises and the speculative costs of providers can well guide the supervision of construction enterprises and work safety service providers to standardize their behaviour.

Solution of digital transformation for offshore work safety management

YU Jin

2023, 33(12):  16-22.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0282

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In order to ensure the safety of China's large-scale offshore oil development, it is necessary to improve the safety level based on the reality of few offshore safety personnel, many risk control points and limited communication between offshore and onshore. At first, this article investigated and analyzed the work list of offshore teams, sorted out the main businesses and digital functions of offshore work safety management based on needs, and clarified the functions' solution of digital offshore work safety management based on scenarios. Then, based on the principles of cloud computing, the work safety management and control points were associated with the management processes at both ends of the offshore and onshore, and a network architecture that can improve work safety management with cloud computing and edge computing was designed to alleviate the constraints of limited bandwidth on the safety management processes implementation. Finally, based on the domain-driven principle, a method of combining micro-service design and safety management elements was proposed, so that on-site personnel can adjust the informatization process according to the actual situation on site, thereby improving the flexibility of digitalization and reducing the impact of changing safety management scenarios on process digitalization. The results show that the core of the digital transformation of work safety management is the realization process of functional requirements in each business field based on the communication environment and sensing system. Under the guidance of this design idea, the digital transformation of offshore work safety management integrates business needs and safety responsibilities, and the dual-domain driven structures the implementation plan of the digitalization.

Safety risk assessment for low and medium altitude general aviation flight plans

HUANG Jingyang, PAN Xuan, FU Xiaorong, GAO Jianwei, PAN Weijun

2023, 33(12):  23-30.  doi:10.16265/j.cnki.issn1003-3033.2023.12.1873

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To promote the air safety of low and medium altitude general aviation, a safety risk assessment system for low and medium altitude general aviation flight plans was established. Firstly, combined with the regulations and policies, safety factors of general aviation flight plans were investigated to obtain the risk assessment indicators, which included the complexities of flight plans, the completeness of equipment, the sites and heights of obstacles, the conflicts of flights, and personnel and environmental conditions. Secondly, the BWM was utilized to process the evaluation information of indicator importance preference, and thus the weights of risk assessment indicators were determined. Thirdly, a series of risk computation models were developed according to the characteristics of indicators based on flight plan information. Finally, the total risk value was calculated and classified into five risk levels from very low to very high, and the risk assessment system for low and medium altitude general aviation flight plans was developed. The results show that the indicator of pedestrian risk has the biggest weight and the indicator of flight plan complexity risk has the smallest weight by using the proposed method. The indicators with high risk of a general aviation flight plan are the complexity of flight plan, the collision of flights and the dispatch release. The total risk value is 0.088 and the risk level is the lowest level. The flight plan is the optimal choice through comparing the total risk values.

Safety engineering technology

Risk assessment model of maintenance organization based on correlation between unsafe information and hazards

WANG Yonggang, WANG Haiyue, ZHANG Di

2023, 33(12):  31-37.  doi:10.16265/j.cnki.issn1003-3033.2023.12.1576

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To reduce human factor errors in traditional expert scoring methods, based on analysis of maintenance risk characteristics, a risk assessment model based on the correlation between unsafe information and hazards was proposed. The average value of the number of unsafe events and the number of non-conformities (violations and other deviations from requirements that have not yet constituted unsafe events) correlated with each hazard within a certain period of time was taken as the risk possibility. If multiple hazards jointly lead to an unsafe event or non-conformity, the number of associations for each hazard is added once. The proportion of occurrence times of each consequence in the total occurrence times of all consequences was taken as the proportion of the severity of such consequence in the total severity of consequences that may be caused by the hazard. The total consequence severity that the hazard may cause was determined by the sum of the product of each consequence's severity and its corresponding proportion. The model was used to analyze a large maintenance organization and statistical analysis was made on nearly twenty thousand unsafe incidents and non-conformance records in the past three years. The results indicate that the evaluation results are consistent with the distribution of hazards found during the inspection of the local regulatory authority in the same period, and the risk assessment model based on the correlation between unsafe information and hazards can objectively quantify the risk level.

Characteristics of mining overburden and surface movement under influence of faults

GUO Wenbing, LIU Xuan, YANG Weiqiang, WU Pengfei, ZHANG Yihui

2023, 33(12):  38-46.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0126

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In order to study the overlying rock and surface response of working faces with faults under mining disturbance, numerical simulation, theoretical analysis, and on-site measurement methods were first used to study the characteristics of overlying rock and surface migration and stress response under the influence of mining near fault working faces. Secondly, a numerical simulation model was established and the characteristics of overlying rock failure and stress response in the mining area near the fault working face were analyzed by combining "fracture arch" and "stress arch". Then, a mechanical model of fault plane slip was established, and the activation tendency of the fault plane in the mining of the hanging wall of the fault was quantitatively analyzed by combining the fault slip tendency index Q_s. Finally, the on-site measurement method was used to analyze the surface movement and deformation characteristics of the fault hanging wall under the influence of mining in Daping coal mine in the Zhengzhou mining area. The research findings indicate that under mining disturbances, the maximum width of "fracture arch" development reaches 221.5 m, and the maximum height reaches 110 m, resulting in a width-to-height ratio of approximately 1∶2. The faulted working face exhibits characteristics of "stress arch" with an asymmetric structure. With the increase of fault depth, the slip tendency of the fault surface shows a trend of increasing, then decreasing, and increasing again. In the curved subsidence zone at the same depth, the slip tendency gradually increases. In the fissure zone at the same depth, it initially decreases before increasing again. In the collapsed zone at the same depth, it increases rapidly. The protective coal pillar on the hanging wall of the fault is left with a 30 m fault that is not activated. The bedrock movement angle and boundary angle of Daping coal mine are 8.8 and 4.6 degrees smaller than those on the working face under general geological conditions in the Zhengzhou mining area, respectively, and 6.7 degrees smaller than those on the working face without faults in the same coal mine.

Fire extinguishing performance and fire extinguishing mechanism of perfluorobutyl methyl ether

WANG Kai, WANG Dezheng, ZHOU Biao, LI Xueyao

2023, 33(12):  47-52.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0775

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In order to comprehensively reveal the fire-extinguishing reaction path of perfluorobutyl methyl ether, its fire extinguishing performance and fire extinguishing mechanism were investigated by combining experimental and theoretical methods. The fire extinguishing performance of perfluorobutyl methyl ether was evaluated by cup combustion test, and its high-temperature thermal decomposition process was simulated by a gas high-temperature pyrolysis mechanism analysis platform, and the pyrolysis products at different temperatures were analyzed by gas chromatography-mass spectrometry. It was found that the critical fire extinguishing volume fraction of perfluorobutyl methyl ether was about 5.90%, and the fire extinguishing performance was good. The initial thermal decomposition temperature of perfluorobutyl methyl ether was 400 ℃, and the pyrolysis products include nonafluoro-1-butane, octafluoro-1-butene, hexafluoropropane and trifluoromethane. The test results revealed the fire-extinguishing mechanism of perfluorobutyl methyl ether, indicating its potential to become a substitute for halon fire-extinguishing agents.

Influence and prediction of climatic factors on forest fires in China

LU Yi, ZHOU Qinyun, SHAO Shuzhen, WANG Wei, DAI Yuqing, WEI Xue'e

2023, 33(12):  53-59.  doi:10.16265/j.cnki.issn1003-3033.2023.12.1736

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In order to explore the influence mechanism of climatic factors on the weight of forest fire accident, firstly, based on the data of forest fire accidents in China from 2011 to 2020, four kinds of climatic factors, including annual average pressure, temperature, precipitation and sunshine time, were selected as characteristic variables. Secondly, the results of forest fire danger zoning were obtained by the hierarchical clustering method, and the grey correlation coefficient was calculated to obtain the influence degree of climate factors on forest fire. Then, the regression model of four types of climatic factors in China was established to obtain the weight ranking of the impact of climatic factors on forest fires, and the risk value in 2021 was predicted. The results show that the fire danger areas in China could be divided into 10 categories under the influence of climatic factors. The influence of climate on the number of forest fires per unit area is ranked as follows: annual average precipitation > annual average pressure > annual average temperature > annual average sunshine time. Linear regression analysis and grey correlation degree analysis have similarities in the ranking results of fire danger zone. The relative error between the predicted risk value by linear regression analysis and the actual value in 2021 is less than 5%.

Research on image recognition technology for external scaffold hidden danger based on improved YOLOv5s

ZHAO Jiangping, LIU Xingxing, ZHANG Xiangzhuo

2023, 33(12):  60-66.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2011

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In order to improve the quality and efficiency of external scaffold safety management, an improved YOLOv5 s external scaffold hidden danger identification method is proposed based on image recognition technology.Firstly, in order to solve the problem that the recognition precision decreases due to more background information, a convolutional block attention module(CBAM) was embedded in the algorithm backbone network to obtain various detailed features of hidden danger. Secondly, the neck feature fusion module was improved into BiFPN, which can effectively deal with the problem of multi-scale feature imbalance caused by the uneven size distribution of scaffolding hidden targets. Thirdly, the original frame loss function was replaced by Scylla intersection over union(SIoU) Loss. Finally, the influence of the improved module on the performance of the model was analyzed by ablation test and compared with other algorithms to verify the recognition effect. The results show that the score of mAP@0.5:0.95 is increased by 5.13%, and the recall rate is increased by 3.45 %. The algorithm has a good recognition effect in multi-scale, the multi-target and complex background of construction sites. It provides technical support for the further application of image recognition technology in the field of external scaffold safety management in a construction site.

Interval non-probabilistic reliability analysis of support structures for deep tunnel

LI Xiang, WEI Heng, WANG Jingtong

2023, 33(12):  67-76.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0546

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Aiming at the current situation of a lack of uncertain data, an interval non-probabilistic tool was introduced to perform a preliminary investigation in the domain of reliability analysis for the support structures of the deep tunnel. Firstly, the mechanism of the shearing slip displacement in the weak rock surrounding the deep tunnel was taken as an illustrative example, and a method was developed to calculate the total support resistance by using the combined support modes. Subsequently, based on the framework of the interval non-probabilistic theory, and meanwhile considering the influence caused by the interval extension problem, the applicability of the interval non-probabilistic tool was discussed for reliability study on the support structures of the deep tunnel. Eventually, a fluctuation range was defined to characterize the variations of the interval used for those uncertain parameters, and on this basis the difference for the level of those effects of fluctuations regarding a single-parameter and multiple-parameters coupling on the reliability of the support structures was revealed via the sensitivity analyses. The results manifest that the greater the fluctuation range of the interval for the uncertain parameters, the smaller the value of the non-probabilistic reliability index will be. Moreover, the larger the number of uncertain parameters involved in the fluctuation coupling, the higher the decrease in the value of the non-probabilistic reliability index will be. Hence, this situation makes the unfavorable effects on the reliability of the support structures more significant.

Construction and analysis of evolution network of runway excursion events

CHENG Ming, MEI Aoran

2023, 33(12):  77-84.  doi:10.16265/j.cnki.issn1003-3033.2023.12.1893

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In order to study the formation mechanism of runway excursion events and reduce the probability of events, this paper analyzed the evolution mechanism of runway excursion events based on scenario deduction and complex network theory, and constructed the evolution network model of out-of-runway events. The static characteristics of the weighted directed network were calculated, including the node degree, betweenness centrality, clustering coefficient and network density. Based on the cascading failure theory, the dangerous propagation path of the evolution network of the runway event was analyzed. The results show that the network density of the evolutionary network is 0.13, the average clustering coefficient is 0.404, and the average path length is 1.549, which shows the small-world characteristics of the network. The comprehensive values of large grounding speed of key nodes, throttle rod and engine damage are 0.508 3, 0.491 2 and 0.487 1, respectively. In the critical path of dangerous propagation, the frequency of grounding speed, throttle rod (operation error) and re-flight in each propagation chain is high, which is an important node in dangerous propagation.

Risk identification and assessment for gas extraction drilling sealing operations

LI Hong, MA Jinkui, TIAN Kunyun, YANG Hao

2023, 33(12):  85-91.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0354

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In order to effectively improve the safety of sealing operation of new sealing material, the safety risk identification method of hazard analysis of operating conditions was adopted to identify the danger sources in sealing operation. The safety risk assessment index system method was adopted to subdivide the sealing operation into 7 first-level risk factor indexes and 34 second-level risk factor indexes. The correlative and dangerous degree of each index factor was quantitatively calculated. The safety checklist method was adopted to check the safety of "human-machine-environment-management" system during the whole process of sealing operation. The safety checklist method was used to check the safety of the "human-machine-environment-management" system in the whole process of the operation. The research results show that cracking of pressurized air pipeline, falling roof plate, fan blade of air-driven mixing drum, corrosion of new materials and blockage of grouting outlet to hold the pressure are the risk factors that are important to be controlled in the drilling and sealing operation. The safety checklist method can be used to comprehensively screen the risks before, during and after sealing operations.

Research progress on thermal stability of combustible dust

LYU Pengfei, GU Xiaoke, LI Gongfang, ZHAO Jing, PANG Lei

2023, 33(12):  92-103.  doi:10.16265/j.cnki.issn1003-3033.2023.12.1228

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In order to prevent and control fire and explosion accidents triggered by the heat change of combustible dust, firstly, through analyzing the domestic and international literature related to dust thermal stability, the influence of heating rate, inert medium, dust particle size and other factors on dust thermal stability were summarized and analyzed. Then, the current status of the multi-instrument linkage between the thermal analyzer and the lowest ignition temperature test device of the dust layer, the Godbert-Greenwald furnace, and Fourier transform infrared spectroscopy (FTIR) and other multi-instruments were summarized. Finally, the commonly used kinetic methods for dust thermal analysis were summarized. The results show that increasing the heating rate will cause a certain delay in the pyrolysis of dust, and the inert medium makes the dust more thermally stable and increases the activation energy, the specific surface area and surface activity of dust particles of smaller size are usually larger, and more energy is released during the pyrolysis process.

Numerical simulation study on air distribution in space of mine ventilation clothing

YOU Bo, YANG Jiao, WU Guoshan, HAN Qiaoyun, YANG Xinyu

2023, 33(12):  104-112.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0254

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In order to improve the cooling performance of mine ventilation clothing and explore the air distribution law in mine ventilation clothing and the influence of different pipeline structures on the cooling effect, this paper established three-dimensional physical models of three different pipeline structures based on the structural characteristics of human body wearing ventilation clothing in static state. The numerical simulation method was used to analyze the mechanism of air flow change and temperature distribution characteristics in the space of human body-ventilated clothing, and the temperature distribution characteristics in microenvironment of clothing were analyzed to judge the cooling effect of ventilation clothing. The results show that the airflow distribution uniformity of the microenvironment under the underwear of the human body-ventilation room formed when the human body wears three kinds of mine ventilation clothes is better than that of the spiral type and the longitudinal type. The total airflow volume of the microenvironment of spiral type is higher than that of longitudinal type and transverse type. For the pipeline structure, the cross pipeline structure greatly affects the utilization rate of airflow. The spiral type has only a single ventilation pipe, and airflow flows along the bend of the pipe, which reduces the local resistance of airflow in the pipeline and improves the airflow utilization rate. Therefore, the spiral type is the optimal choice for pipeline structure. The total air volume inside the microenvironment affects the cooling effect of the clothing. The cooling performance of the three kinds of mine ventilation clothing is that spiral type is better than longitudinal type and transverse type.

Effect of crude oil immersion on micropore structure of coal

SHUANG Haiqing, WEI Mengmeng, BAI Yang, ZHANG Jin, TIAN Yu, ZHANG Xing

2023, 33(12):  113-121.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2396

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In order to study the change law of coal pore structure after crude oil immersion, typical coal samples associated with kerosene mine were selected and immersed in crude oil for different days. The changes of pore morphology, type, pore volume and specific surface area of coal before and after oil immersion were studied by mercury intrusion method and low temperature nitrogen adsorption method, and the microscopic mechanism of crude oil invading coal was revealed by scanning electron microscope (SEM). The research shows that after the coal sample is immersed in crude oil, the mercury entry and exit curve and the low temperature adsorption and desorption curve have obvious weakening trends. The tiny pores of the coal sample change from the original parallel plate pores to the wedge-shaped pores, and the connectivity between the pores becomes worse. With the increase of oil immersion days, the effect of crude oil immersion on coal porosity is obvious. Compared with raw coal samples, the total pore volume of coal samples is reduced by 32%-80%, and the pore volume of macropores and mesopores decreases significantly. The total pore specific surface area of coal samples decreases by 87%-94%, and the specific surface area of small pores and micropores decreases significantly. The flow of crude oil in coal can be roughly divided into three parts: the penetration of large pores and fractures-the filling of medium and large pores-the blockage of small pores.

Study on stress model and critical conditions for coal breaking by submerged jet

WANG Fengchao, LIU Yingke, ZHANG Liyao, XU Rui, NIU Yue, JIANG Mingjun

2023, 33(12):  122-130.  doi:10.16265/j.cnki.issn1003-3033.2023.12.1244

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In order to explore the critical conditions of coal breaking by submerged jet in the hydraulic pressure relief and permeability enhancement operation of coal mines, the stress model of submerged jet impinging on coal body was established by using the theories of turbulent jet, contact mechanics and momentum theorem. The distribution of surface stress on coal body under the submerged jet impinging was studied through discrete numerical solutions for the established stress model. Then, the critical conditions of coal breaking by submerged jets were determined according to the maximum normal stress criterion. Finally, the correctness of the above theory was verified through on-site tests of submerged jet coal breaking at Jinjia mine in Guizhou. The results show that the maximum principal stress of coal is axial compressive stress in the impact zone, while it is radial tensile stress outside the impact zone. Whether inside or outside the impact zone, the maximum principal stress on the coal surface, central symmetry, decreases with the radial distance. The critical pressure and nozzle diameter of submerged jet coal breaking increase with the coal strength and impact target distance. The larger the target distance is, the greater the impact of coal strength on critical conditions. A submerged jet is only suitable for crushing soft coal seams, while a non-submerged jet or accompanying jet can be used for crushing hard coal.

Causation analysis of ship accident severity based on ordered choice model

JIANG Yujie, WAN Zheng, CHEN Jihong

2023, 33(12):  131-139.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0245

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In order to explore the factors that affect the severity of ship accidents, a ship accident analysis method based on an ordered choice model was put forward. Firstly, based on 604 investigation reports of ship accidents in coastal waters issued on the official website of the China Maritime Safety Administration and its direct subordinate organizations, as the dependent variable, the severity of ship accidents was divided into minor accidents, general accidents, and larger and above accidents. Secondly, from five aspects of ship, environment, crew, management, and accident, 19 potential influencing factors were selected. Thirdly, the ordered choice model (including the ordered Logit model and ordered Probit model) was utilized to identify the significant factors affecting the severity of ship accidents. In addition, the marginal effect of the best model was used to quantify the influence direction and degree of significant factors on the severity of ship accidents. The findings indicate that the significant influencing factors identified by the two ordered models are the same, including ship operation status, strong wind, failure to adopt safe speed, improper hazard judgment, improper use of navigation equipment, insufficient staffing, inadequate safety management, autumn, winter, coastal routes, collision, and self-sinking. All the significant influencing factors meet the parallel line hypothesis. The fitting effect of the ordered Probit model is better than that of the ordered Logit model. All the significant influencing factors have a positive effect on larger and above ship accidents. In terms of impact degree, collision is the largest (the absolute value of the marginal effect is 20.44%), and improper hazard judgment is the smallest (4.94%).

Public safety

Systematic analysis on causative factors of gas pipelines leakage accidents in urban underground

XIANG Pengcheng, ZHANG Ziwei, LI Hui, JIA Fuyuan

2023, 33(12):  140-147.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2162

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To prevent gas pipeline leakage accidents in urban underground, the composition and correlation of accident causes were analyzed by this paper from the perspective of the complex system, and the system failure mechanism was revealed. The WSRH (Wuli-Shili-Renli-Huanjing) analysis framework was established by this paper to identify the causes of accidents. Based on the grey number theory, the DEMATEL-ISM method was improved by this paper to establish the multi-level recursive structure model, which was used for the analysis of accident-cause relationship and to determine the key factors and critical failure path. The results show that the leakage accident of urban underground gas pipeline is the result of direct cause, transitional cause and essential cause. There are complex correlations among these factors. There are 7 key causes of system breakdown, forming 8 critical failure paths. The most important of the key causes is the lack of strict implementation of safety education. In the management, priority should be the key cause. Then, according to the critical failure paths, the causes are optimized one by one to realize the safe operation of urban underground gas pipeline system.

Resilience assessment of multi-modal regional rail transit networks considering grey attack

MA Fei, GOU Huiyan, YANG Mengnan, LIU Qing, WEI Xiaolin, AO Yuyun

2023, 33(12):  148-159.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0626

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In order to effectively describe the multi-modal regional rail transit network and improve the accuracy of its network resilience assessment, according to the coupling relationship between different sub-network layers and characteristics of transportation services, MRRT interdependent network model was constructed based on complex network theory. Considering the network topology and service quality, the network resilience measurement index was constructed from four dimensions: resistance ability, absorption ability, buffer ability and recovery ability, and the method of identifying its key stations based on gravity model was improved. Due to the high complexity of MRRT network, the potential attack information disturbed by emergencies had grey characteristics. Therefore, using Matlab to simulate the grey attack strategy under different information accuracy, the influence rule of the information accuracy of grey attack on the resilience of MRRT interdependent network was explored. The research shows that the interdependent network of MRRT has the characteristics of scale-free network. Identifying key stations evaluation index based on the gravity model can improve the accuracy of key evaluation of network nodes. Reducing the information accuracy α of grey attacks can improve network resilience, and there is a threshold for the impact of α on network resilience. When α∈(0.2,0.8), the performance loss of network after being attack decreases as the increase of information accuracy α. When α≥0.8∪α≤0.2, reducing the information accuracy α has no significant impact on network resilience.

Two-stage optimization of vehicle routing problem for hazardous materials with time windows

CHAI Huo, HE Ruichun, HAN Wei, JIA Xiaoyan, DAI Cunjie

2023, 33(12):  160-166.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2080

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In order to effectively reduce the risks and costs of road transportation of hazardous materials, aiming at vehicle routing problem(VRP)for hazardous materials with time windows(HMVRPTW), a two-stage optimization was studied. First of all, according to its characteristics, it was divided into bi-objective shortest path problem and bi-objective VRP with time window. Secondly, the mathematical models were established and two-stage methods were designed to solve them. In the first stage, the pulse algorithm was used to filter the path to obtain the Pareto-optimal path between the distribution center and each demand node. In the second stage, an ant colony algorithm was designed for the bi-objective VRP with time window. Then, taking the test of 9 nodes and 17 edges as an example, the solution process was explained. Finally, taking the oil delivery of 16 gas stations in the main urban area of Lanzhou city as an example, this method calculated an average time of 24.38 seconds to obtain the Pareto-optimal solution for the vehicle scheduling, while using multi-objective genetic algorithm, the average time was 41.05 seconds. The results show that the proposed method simplifies the problem scale through the filtering paths, fully consider the changes in risk and the constraint of time window of hazardous materials transportation, and guides the ants to search for optimization in the specified search space. The proposed method has obvious advantages in efficiency compared to the multi-objective genetic algorithm.

Coupling smoke information and Monte Carlo simulation for evacuation of tunnel fires and its optimization

ZHANG Xiaochun, CHEN Linjie, ZHOU Geyao, ZHANG Zhaomin, WEI Ruichao, WU Binbin

2023, 33(12):  167-175.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2206

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In order to ensure the safe evacuation of people under tunnel fire, a tunnel in Guangzhou city was studied as an example. Firstly, 18 simulation conditions were formed by the combination of three factors: fire heat release rate, natural wind speed and fire location. Secondly, the available safe evacuation time (ASET) was solved with the fire dynamics simulator(FDS), and the hazard characteristic parameters such as smoke visibility, temperature and CO concentration in the grid were obtained. Then, the smoke information was coupled with Monte Carlo simulation to solve the required safe egress time (RSET) and fractional effective dose (FED) with the Pathfinder. Finally, the double criterion (whether ASET was greater than RSET or not, and whether individual risk value FED exceeded the standard or not) were used to analyze the scenarios, and the hazard scenarios were optimized and their effects were quantified. The results show that the personnel evacuation risk is significantly correlated with the fire heat release rate and natural wind speed, but has nothing to do with fire location. In addition, the evacuation optimization efficiency of the method based on zonal evacuation and dynamic exits is more than 10%.

Risk analysis on fire accident of urban commercial complex based on fuzzy Bayesian network

QIN Rongshui, SHI Chenchen, CHEN Chao, LAN Meng, LIU Xiaoyong, XIAO Junfeng

2023, 33(12):  176-182.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0879

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To effectively reduce the risk of fire accidents in urban commercial complexes, firstly, based on the causal analysis of the evolution process of fire accidents and influencing factors, the corresponding Fault Tree (FT) and Event Tree (ET) models were constructed. Then they were mapped into Bayesian networks (BN) to determine the conditional relationships between influencing factors. Secondly, fuzzy theory based on expert judgment was used to determine the prior probabilities of basic events. The FBN model was constructed to overcome the uncertainty of failure probabilities of risk factors. Finally, the FBN-established risk assessment model was utilized to perform bidirectional inference and sensitivity analysis for fire accidents of urban commercial complexes, identifying the key influencing factors leading to fire accidents at different severity levels. The study indicates that strengthening fire and smoke zoning design, increasing the fire resistance rating of fire separation facilities, installing fire separation facilities reasonably and reducing the failure rate of smoke exhaust systems can effectively prevent the occurrence of high-loss risk-level fire accidents.

Evacuation model considering visually impaired pedestrians

SUN Huakai, CHEN Changkun, WENG Jiajun, ZHU Kai, WU Ke

2023, 33(12):  183-191.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2081

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In order to study the influence of visually impaired pedestrians on crowd evacuation, a floor field cellular automata evacuation model was established to simulate the movement state and evolution process of crowd evacuation in the place where visually impaired pedestrians appeared. In the model, the evacuation behavior of visually impaired pedestrians was described by combining with the controlled experiment phenomenon of ISOBE et al., and the helping behavior of normal pedestrians to visually impaired pedestrians was considered. Besides, the movement of the small group was determined by the movement probability and modified Moore neighborhood. Then the influence of normal pedestrians' helping behavior, the proportion of visually impaired pedestrians and the exit location on the evacuation were studied using the model. The results showed that the helping behavior of normal pedestrians to visually impaired pedestrians could effectively reduce the evacuation time, and the beneficial effect of helping behaviors on the evacuation efficiency became more significant as the crowd density increased. The evacuation efficiency would reduce when the proportion of visually impaired pedestrians in mixed crowds increased, and this adverse influence would increase as the crowd density increased. Compared with the exit at the corner and the exit near the side wall, the location of the exit in the middle of the wall is more beneficial to the evacuation of mixed crowds.

Technology and engineering of disaster prevention and mitigation

Risk analysis of rainstorm flood disaster chain and research on disaster mitigation of broken chain under complex network

LI Lei, MA Mengge, SHE Yaya, WANG Yuqiu, FANG Zihao, WANG Fan

2023, 33(12):  192-197.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2006

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In order to improve the emergency response and disaster rescue capability of rain and flood disasters, the risk analysis on the rain and flood disaster chain under complex networks was conducted in this study. The secondary derivative disaster events and interrelationships of rain and flood disaster were counted and the network topology structure of the rain and flood disaster chain was constructed. The rain and flood disaster risk assessment model was established, and the node importance degree, the edge vulnerability degree and the risk degree of disaster chain were calculated. The results show that the two chains of "rainstorm-landslide-infrastructure damage" and "rainstorm-landslide-road-bridge destruction-traffic paralysis" are the key points in the prevention and control of rain and flood damage. Controlling important nodes before the occurrence of rain and flood disasters, and cutting off the edge with high risk in time after the occurrence of rain and flood disasters can effectively prevent the occurrence and spread of secondary derivative events of rain and flood disasters.

Study on resilience of airport infrastructure under blizzard weather

HUANG Xin, TAN Chengsong, WU Kun, QI Lin, CHEN Yu

2023, 33(12):  198-205.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2542

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To ensure the safety of airport operations under major natural disasters, the resilience index system consisted of physical resilience, functional resilience, economic resilience and organizational resilience was proposed, and the resilience index was evaluated by expert questionnaires. CFA model was established, and the influence of various resilience index on the resilience of airport infrastructure was systematically analyzed. The weight of the evaluation index was determined by CFA model. Based on a fuzzy comprehensive evaluation, the resilience level of airport infrastructure was evaluated. Results show that the established evaluation index of airport infrastructure resilience has good reliability and convergence validity. The proposed evaluation system of resilience indexes is reasonable. Compared with the physical, economic and organizational resilience, the functional resilience is the most significant for the resilience of airport infrastructure. Through fuzzy comprehensive evaluation, the fuzzy comprehensive evaluation value of airport infrastructure is 73.4, which indicates that the airport infrastructure has a good resilience level, and the proposed quantitative evaluation method can be used to evaluate the resilience of infrastructure.

Emergency technology and management

Evaluation method of collaborative capacity of cabin fire emergency response based on cloud model

WU Yu, YANG Meng, ZHANG Qingsong

2023, 33(12):  206-213.  doi:10.16265/j.cnki.issn1003-3033.2023.12.0313

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In order to solve the problems of subjective evaluation of virtual emergency drill and difficult evaluation of multi-users collaborative effect, a method of evaluating emergency coordination capacity was proposed based on cloud model. Firstly, from the perspective of team cooperation and post competence, combined with the drill platform based on VR technology, the virtual drill process of emergency response in cabin fire was proposed, and the evaluation index system of emergency coordination capacity was constructed. Secondly, the actual process data of cabin crew in disposing of cabin fire emergency drill were collected and processed dimensionless. The drill results were calculated based on the cloud model and simulated by Matlab. Finally, competition mode and training mode were designed to realize the evaluation of emergency coordination capacity of multiple groups under different modes. The results show that this method could objectively collect the data of the drill process, quantitatively analyze the emergency capacity of cabin crew under different modes, and intuitively sort the results of each drill, which meets the actual requirements of cabin crew to improve their emergency drill capacity.

Occupational health

Prediction of occupational health damage caused by coal mine noise based on t-SSA-BP

GAO Xiaoxu, GAO Lu, PAN Xiangxu, GAO Xiang, MA Hao

2023, 33(12):  214-222.  doi:10.16265/j.cnki.issn1003-3033.2023.12.2068

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In order to accurately predict the occupational health damage of workers exposed to noise in coal mines, the influencing factors were selected based on the quantile plot method. According to the noise occupational health damage assessment method, the adaptive t distribution variation operator and SSA were used as parameter optimization algorithms to establish the t-SSA-BP coal mine noise occupational health damage prediction model, and the benchmark function was used to test the optimization performance of the algorithm. 10 coal mines in northern Shaanxi were taken as the research objects, and the prediction model was verified by field investigation, theoretical analysis and Matlab simulation. The results show that the noise exposure intensity, individual age, length of service and noise exposure post are the influencing factors of noise health damage in coal mines. The overall accuracy of t-SSA is 66.0%, which is higher than that of SSA in four benchmark functions. The order of accuracy of the five prediction models is: t-SSA-BP>SSA-BP>PSO-BP>CFA-PSO-RBF>PSO-GRNN. Compared with SSA-BP, the MAE and MAPE of t-SSA-BP prediction model decreases by 68.1% and 66.7% respectively, and the R² reaches 0.999. The prediction accuracy and convergence rate are significantly improved.