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Table of Content

    28 October 2022, Volume 32 Issue 10
    Safety science theory and safety system science
    Exploring "two lines and one frame" education mode for curriculum politics of safety discipline in colleges and universities
    TONG Ruipeng, WANG Lulu, CHEN Xingbang, WANG Leyao, AN Yu
    2022, 32(10):  1-7.  doi:10.16265/j.cnki.issn1003-3033.2022.10.0614
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    In order to effectively carry out the construction for curriculum politics of safety discipline, and to promote the organic unity of discipline knowledge transmission, value shaping, and ability cultivation, research on the essential connotation and education mode for curriculum politics of safety discipline was conducted. Firstly, the implication and specificity for curriculum politics of safety discipline were identified. Secondly, the concept of "two lines and one frame" education mode for curriculum politics of safety discipline was put forward, which was applied at China University of Mining and Technology-Beijing. The results show that the curriculum politics of safety discipline can be understood as the infiltration of ideological and political education in the teaching of safety discipline courses. The knowledge line of the safety discipline and the logical line of political education are the important support for the construction of the mode. The objects of talent cultivation, education strategy, evaluation and optimization of educational effect are the basic elements of creating a pattern of the curriculum politics of safety discipline. Besides, by applying the mode, it has been able to satisfy the needs of moral education in safety discipline and improve the quality of talent cultivation.

    Main achievements of construction engineering safety management: review of safety accidents, safety management system, and relevant literature
    ZHENG Wenbo
    2022, 32(10):  8-17.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1932
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    In order to improve the safety management level of construction engineering, the characteristics of construction engineering safety accidents in the world were analyzed, the typical national institutional arrangements were explored, and the achievements and shortcomings of academic research were summarized. The results show that the overall trend of construction engineering safety accidents in the world changed from a large number of accidents with a low fatality rate to a small number of accidents with a high fatality rate, and the number of accidents and fatality rate in China increased first and then decreased, and remained at a low level. More attention has been paid to safety management at the bottom of the system (enterprise and market) in the United States, and design at the top of institutions (laws and organizations) has been more important in China and Vietnam, and both have been tightly controlled in Singapore. Fruitful results in four aspects have been achieved of literature research, safety evaluation indicators have been determined, safety accident occurrence and response mechanism have been explored, safety management investment has been calculated, and safety atmosphere measurement and mechanism have also been analyzed.

    Safety social science and safety management
    Impact of non-compliance tasks on unsafe behavior of new generation miners
    LI Naiwen, LIU Yaping, NIU Lixia
    2022, 32(10):  18-24.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2111
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    In order to explore the influence mechanism of non-compliance tasks on miners' unsafe behaviors, organizational self-esteem and mind wandering were introduced to construct a chain mediation model. A total of 499 new generation miners were investigated by using non-compliance tasks scale, organizational self-esteem scale, mind wandering scale and unsafe behavior scale, SPSS26.0 and AMOS23.0 software were used for correlation analysis and mediating effect test. The results show that non-compliance tasks can not only directly predict the unsafe behaviors of the new generation of miners, or indirectly affect the unsafe behaviors of the new generation of miners through the independent mediating role of organizational self-esteem and mind wandering, as well as the chain mediating role of organizational self-esteem and mind wandering. Effectively controlling of non-compliant tasks, organizational self-esteem and mind wandering can reduce the frequency of unsafe behaviors and the occurrence of accidents.

    Revision and application of Chinese version of risk attitude scale
    LIU Jin, SHEN Hao, LIU Zhuohui, CHEN Sitong, XIONG Zhixiang, PAN Chuan
    2022, 32(10):  25-30.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1479
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    In order to measure individual risk attitude of and reduce unsafe behavior, the Chinese version of the risk attitude scale was revised to discuss the structure of the scale in Chinese culture. A total of 250 risk attitude questionnaires were distributed and 220 valid questionnaires were collected. The reliability and validity of the questionnaires were analyzed by SPSS software. The results show that the revised risk attitude scale consist of four factors: attitude towards risk acceptance, attitude towards approaching risk acceptance, attitude towards risk avoidance and attitude towards risk rejection. with a total of 32 items, and the cumulative contribution rate is 75.43%. The Cronbach's α coefficient of the scale is 0.796, with good reliability. The chi-square degree of freedom ratio (CMIN/DF) of the scale is 1.832, the increment fitting index (IFI) is 0.905, the comparative fit index (CFI) is 0.904, the root of mean square residual (RMR) is 0.038, and the root mean square error of approximation (RMSEA) is 0.049, indicating that the scale has good structural validity. Through unstructured interviews with experts and related scholars, some items are modified and deleted, and the content validity of the scale is good.

    Research on key risk control mechanism of urban safety based on system dynamic
    WANG Xiaoqing, CHEN Dong, WANG Anna, QIAN Chengjiang
    2022, 32(10):  31-39.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1660
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    In order to study evolution trend of key risks in urban regional work safety and establish an effective risk control mechanism, according to actual survey results in a prefecture-level city in Jiangsu Province, main risk factors in three key industries, namely transportation, construction and commercial places, were deeply analyzed in view of their field characteristics. Then, a system model of key risks in urban work safety was constructed by using SD theory and method, and risk value was dynamically simulated by adopting Vensim software. Finally, countermeasures to improve urban intrinsic safety were put forward from perspectives of actual risks of the three key industries based on survey data and simulation results. The results show that the evolution trend of key risks in urban work safety is roughly as slow decrease → extremely rapid decrease → gradual flattening out. Moreover, risk influencing factors, total risk, number of risk elimination, rate of risk elimination, and turning point of risk elimination of the three key industries are different due to different industries.

    Safety engineering technology
    Signal identification of fracture in gas bearing coal based on dual strategy coupling optimization
    FU Hua, ZHAO Juncheng, LIU Hao, LIU Yuzhu, LU Wanjie
    2022, 32(10):  40-47.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1868
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    In order to address identification problems of signal characteristics of fracture in gas bearing coal during fracture process, with Bi-directional Long Short-Term Memory network (BiLSTM) as base classifier, a dual strategy coupling optimization identification model for such signal characteristics was proposed based on AdaBoost algorithm and HHO algorithm. Firstly, in view of the problem that proportion of error samples in AdaBoost algorithm increased with iteration, which had an impact on results of final strong classifiers, weight parameters were introduced and weights of weak classifiers were changed so as to improve identification. Then, to determine optimal model parameters, identification parameters and weight parameters were optimized based on HHO, and during optimization process, HHO and improved AdaBoost algorithm produced a coupling effect, which made the identification model's accuracy and stability reach optimal level, resulting in an average accuracy of 91.36% and standard deviation being reduced to 0.017 4. The results show that the dual strategy coupling optimization model of HHO-AdaBoost-BiLSTM identification of signal characteristics of fracture in gas bearing coal has higher accuracy and stability.

    Safety risk assessment of blasting in open-pit mine based on SNA
    KE Lihua, CHEN Kuixiang, HU Nanyan, TAN Ming, ZHANG Guangquan, MENG Huanhuan
    2022, 32(10):  48-56.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2045
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    In order to reduce casualties and accident losses caused by blasting safety accidents in open-pit mines, SNA was used to construct the relationship network model of blasting safety risk factors in open-pit mines (A model network) and the relationship network model between safety risk factors and safety accidents (B model network). The relationship between risk factors and blasting accidents and risk factors was studied, and the risk assessment model of open-pit blasting safety based on SNA was proposed. It is determined that the core risk factors affecting the blasting safety of open-pit mines were inadequate guidance and inspection of blasting technology, weak safety awareness and illegal operation. And the key relationship of key control is from bad weather to illegal operation. After risk control, the overall network density and intermediate center potential of the network decreased by 75% and 100%, respectively. Researches has shown that risk can be effectively controlled through targeted intervention of core risk factors and cutting off key relationships.

    Slope seepage failure analysis based on improved Green-Ampt model
    REN Qingyang, CHEN Bin, MENG Xin, JIN Honghua, BIAN Linlin, ZHENG Shiyue
    2022, 32(10):  57-62.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2246
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    In order to solve the safety and stability problem of slope water seepage failure caused by rainfall, taking a bridge foundation slope as an example, the Green-Ampt infiltration model was improved by fully considering the catchment effect of slope flow. Based on the improved model, the temporal and spatial characteristics of slope rainwater infiltration under continuous heavy rainfall were calculated, and the progressive failure process of slope with rainwater infiltration is simulated by FLAC3D software. The results show that the characteristics of the wetting front obtained by the improved model are in agree with the engineering practice. The farther away from the slope top, the greater the rainwater infiltration depth, and the slower the rainwater infiltration rate with the extension of the rainfall time. The depth of the wetting front caused by overland flow accounts for a large proportion of the total depth, andwhich is more than 50% at the front of the slope in the first 5 hours. The failure of slope develops gradually from toe to top and from shallow to deep, and has obvious characteristics of time discontinuity and multi-layer progressive backward progressive damage.

    Experimental study on synergetic fire extinguishing performance of water mist and inert gas
    LUO Zhenmin, WANG Xin, WANG Tao, MENG Ziqi, WANG Zijin
    2022, 32(10):  63-68.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2237
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    In order to improve the fire extinguishing efficiency of water mist, the fire extinguishing performance and synergistic fire extinguishing effect of water mist, inert gas nitrogen (N2) and carbon dioxide (CO2) were studied by experimental study and mathematical model analysis. The single and compound fire extinguishing effects of water mist and inert gas were tested by a self-designed cup burner test device, and a mathematical model of synergy factor suitable for water mist and inert gas was established. The results show that the minimum volume fractions of N2 ethanol-extinguishing fire and heptane-extinguishing fire were 34.92% and 31.97%, respectively, and that of CO2 ethanol-extinguishing fire and heptane-extinguishing fire were 24.37% and 22.15%, respectively. From the perspective of synergistic effect, there is a positive synergistic fire extinguishing effect between water mist and N2, but the synergistic fire extinguishing effect with CO2 is not obvious, and there is no synergistic fire extinguishing effect between N2 and CO2.

    Development and application of risk assessment model for prefabricated building construction
    WANG Dan, LIANG Jinghan
    2022, 32(10):  69-75.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2119
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    In order to reduce the construction risks of prefabricated building projects, indexes were refined based on accident analysis and other methods, and the construction risk evaluation index system of prefabricated buildings with 5 primary indexes and 26 secondary ones was established. Then, the contingency theory and nearness degree were introduced to replace constant weight assignment method and correlation degree algorithm in traditional matter element extension method, and the construction risk assessment model of prefabricated buildings based on the improved matter element extension was constructed. Finally, the model was applied to validate the case whose construction risk level was obtained to be 1, namely low risk, and effectiveness of the model was verified by comparing its assessment results with those of the traditional one. The results show that the assessment model based on the improved matter element extension method can be applied to effectively evaluate the project risk status before the occurrence of accidents and achieve the purpose of improving risk management benefits.

    Online fault diagnosis of mine ventilation system based on OCISVM
    ZHAO Dan, SHEN Zhiyuan, LIU Xiaoqing
    2022, 32(10):  76-82.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1766
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    In order to address the difficulty in obtaining failure samples of mine ventilation system and the lack of research on online detection to fill the blank in fault branch diagnosis based on real-time monitoring data of sensors, OC-SVM and IL method were combined to construct OCISVM model. Firstly, monitoring data of normal samples were used to construct classification hyperplane at offline phase. Then, at online detection stage, classification hyperplane was updated by introducing delta function according to incremental learning, and online fault branch diagnosis was achieved based on threshold criterion. Finally, the proposed model was applied to Dongshan coal mine ventilation system. The results show that the model's fault diagnosis accuracy can reach as high as 96.5% while running in milliseconds. Moreover, it demonstrates higher stability when dealing with unbalanced data.

    Effect of N2-water mist-slip device on methane explosion characteristics
    DUAN Yulong, BU Yunbing, LONG Fengying, LI Yuanbing, HUANG Jun, YU Shuwei
    2022, 32(10):  83-89.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1861
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    In order to further explore the synergistic explosion suppression effect among various explosion suppression technologies, the methane explosion characteristics under the combined action of no pressure (0 MPa), low pressure (0.1, 0.2 MPa) nitrogen-water mist and different elastic coefficients (0.42, 0.81 N/mm) limit slip devices were carried out on a self-built 100 mm×100 mm×1 000 mm square pipeline explosion platform. The results show that the development of the "tulip"\|shaped flame structure is hindered by the coupling effect of the nitrogen-containing water mist and the sliding device, the sliding device makes the combustion zone form a variable-capacity restricted space, its volume is proportional to the flame propagation speed, the explosion overpressure in each working condition decayed, and the decay rate of the burned area was slightly greater than that of the unburned area. Under the action of 0.1 MPa nitrogen-water mist under the two elastic coefficients, the overpressure peak in the burned area decreased by 12.92% and 16.07%, respectively, and the overpressure peak in the unburned area decreased by 11.97% and 15.12%, respectively.

    Causation analysis model for ship traffic accidents based on C5.0 decision tree and application
    HUANG Changhai, SHEN Jia, ZHU Ranchao, QI Xucun, ZHENG Fei, LU Hao
    2022, 32(10):  90-99.  doi:10.16265/j.cnki.issn1003-3033.2022.10.0483
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    In order to reduce the occurrence of ship accidents, the causation of ship traffic accidents was analyzed. Firstly, a ship traffic accident causation path analysis model based on the C5.0 algorithm was constructed. The model took accident type as the output variable and the ship traffic accident data as samples. Then, the evaluation indexes of validity for path analysis of accident causation were established. Furthermore, the 24Model was used to analyze the causal relationship of different types of accident paths. Finally, the prevention and control measures for ship traffic accidents were proposed by cutting off the potential causation path of accidents. Taking 894 ship traffic accidents as an example, the sample set was randomly divided into 80% training set and 20% test set, and the proposed model was used for analysis. The research results show that the proposed model can generate a set of classification rules for different types of accidents, the classification accuracy rate of the model is over 90%, and the model has a strong generalization ability. The causal chain of ship traffic accidents constructed in combination with the classification rule set provides a quantitative theoretical basis for the prevention of accidents.

    Comparative analysis of explosion suppression performance of nonmetallic spherical spacers and mesh aluminum alloys
    YU Yangyang, LIU Lehai, ZHANG Junhong, JI Ning, MENG Xiangde, ZHOU Tianyi
    2022, 32(10):  100-106.  doi:10.16265/j.cnki.issn1003-3033.2022.10.0138
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    In order to study the explosion suppression performance of NSSs and MAAs on propane in closed space. NSSs and MAAs with a density of 45.1 kg/m3 were filled in a CVCB, and the explosion test was carried out after premixed propane-air. Explosion suppression effect and contrast of NSSs and MAAs were analyzed and compared including overpressure, the maximum explosion overpressure time and the maximum explosion overpressure reduction rate. The average propagation velocity of the filled flame front was calculated and compared by flame schlieren image. the The turbulent combustion phenomenon was analyzed and the explosion suppression performance under different equivalence ratios was compared. The results showed that the effects on explosion suppression of NSSs was better than that of MAAs. With the increase of equivalence ratio, the maximum explosion overpressure reduction rate of NSSs and MAAs first decreased and then increased, and the average flame velocity of NSSs and MAAs first increased and then decreased. The suppression effect was lower under the equivalence ratio of 1 than that of another equivalence ratios (0.8, 1.2, 1.5 and 2.0). As a result, with the concentration of propane increasing, suppression effect increased.

    Analysis of deflagration characteristics of leakage gas on an offshore platform
    MA Chenbo, LU Xinyi, LIU Xiangdong, HU Dong, WU Xu, CAO Yang
    2022, 32(10):  107-114.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2741
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    In order to evaluate deflagration consequences arising from natural gas leakage on a domestic offshore platform, ANSYS Fluent software was used to simulate the evolution process of deflagration accidents. Firstly, a three-dimensional model was established based on the structure and equipment layout of the offshore platform. Then, the spatial and temporal distribution characteristics of three key parameters, overpressure of deflagration, high temperature and thermal radiation intensity of combustion, were investigated. Finally, the hazardous area and influence range of the deflagration were analyzed, and the corresponding safety prevention suggestions were proposed. The results show that overpressure has the most serious effect on the three-phase separator and heater skid, while other facilities (i.e., Christmas trees, laboratory and central control room) are less affected by overpressure. The minimum distance to ensure the safety of humans under overpressure is 22.5 m downwind side of the ignition source. The impact of high temperature on facilities is mainly reflected in the three-phase separator, Christmas trees and column. The hazardous area generated by high temperature is extended to the living quarter. Deformation of facilities on lower deck can be caused by thermal radiation of combustion, and personnel burns can be caused the continuous thermal radiation.

    Fire smoke spread characteristics of T-shaped bifurcated tunnel under longitudinal ventilation
    YAO Yongzheng, SONG Kebin, SHI Congling, REN Fei, LI Jian, CHE Honglei
    2022, 32(10):  115-120.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1590
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    In order to study the characteristics of fire smoke spread in T-shaped bifurcated tunnels under longitudinal ventilation, a full-scale numerical model of the bifurcated tunnel was established using fire dynamics simulation(FDS) numerical simulation software. By changing different longitudinal ventilation and heat release rates, the temperature distribution and smoke flow characteristics were studied. The results show that: With the increase of longitudinal ventilation, the upstream fire smoke temperature in the bifurcated tunnel decreases first and then increases, and the velocity field in the bifurcated tunnel changes from inclined to upstream of the fire source to inclined to downstream of the fire source. The maximum smoke temperature in the main tunnel increases first and then decreases with the increase of longitudinal ventilation. The turning longitudinal ventilation speed is 2 m/s, and the maximum temperature of fire smoke is basically near the fire source. The smoke spread front in the main tunnel gradually moves downstream with the increase of longitudinal ventilation speed. When the longitudinal ventilation speed is 3 m/s, the smoke spread front is close to the fire source area.

    Research on preparation of film-forming colloidal foam and its fire extinguishing and cooling characteristics
    SHI Quanlin, YANG Hongqi, LI Hongbiao
    2022, 32(10):  121-126.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2201
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    Aiming at the poor stability and short time for oxygen isolation of the existing fire-extinguishing foams, the novel colloidal foam technology with long-lasting water retention and film-forming function has been developed. The influence of the composition ratio on the foaming and stability of colloidal foam, its film-forming characteristics, and its inhibition and extinguishment characteristics were analyzed. The results show that the prepared colloidal foam using 0.3% foaming agent, 0.4% thickening agent(TA), and 0.3% crosslinking agent(CA)exhibited the best comprehensive performance with the half-life and expansion ratio above 120 h and 5 times respectively. Moreover, colloidal foam could wrap the high-site ignition sources quickly to cover and extinguish. In addition, there would be a dense colloidal oxygen barrier film formed from the drying colloidal foam on the surface of the coal, which achieved the long-lasting prevention and control of coal spontaneous combustion.

    Association rules mining of water traffic accidents causation under value attenuation
    YANG Lichao, LIU Jingxian, LIU Zhao, LIU Yiwei
    2022, 32(10):  127-134.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2087
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    In order to improve the traffic safety level of China's coastal waters, an Apriori algorithm based on time weight was proposed on the basis of considering the value attenuation of water traffic accidents. Taking the data of water traffic accidents in China's coastal waters from 2015 to 2020 as samples, the characteristics of water traffic accidents in China's coastal waters were analyzed,and the potential mapping relationship between accident attributes and causal attributes were explored, to form 13 strong association rules. The results show that the mining value of traffic accident has the characteristics of decaying with time. The coastal waters of China have the characteristics of high incidence of water traffic accidents in fixed seasons, fixed periods, specific vessels and special waters. There is a ctetain mapping relationship between the basic attributes of accidents and the causal attributes. Some causal attributes often appear at the same time under the specific basic attributes of accidents.

    Experimental study on effect of blockage on smoke temperature in tunnel fire
    YANG Yuxuan, CHENG Huihang, LONG Zeng, CHEN Junfeng, LIU Chang, ZHONG Maohua
    2022, 32(10):  135-141.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1792
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    In order to study the influence of blockage effect on the smoke temperature distribution characteristics in a tunnel fire, a series of 1∶20 small-scale model experiments were carried out in this paper. By varying fire power parameters, tunnel slope, blockage location and blockage length, the smoke spread time, maximum ceiling temperature rise and dimensionless longitudinal temperature distribution in the tunnel fire have been analyzed in depth. The results show that: the blockage length has little effect on the smoke temperature characteristics, while the blockage location has a greater impact. The spread speed of smoke to the side with blockage is greater than that in the scenario without blockage, and greater than that in the scenario with blockage on another side of the fire source. When the fire power changes, the location effect of blockage will also change. Due to the blockage effect, the smoke temperature attenuation rate decreases during the longitudinal spread of smoke to the side with the blockage, while the longitudinal spread to the side without blockage is not disturbed by this effect.

    Study on thermal radiation in upwind area of aviation kerosene pool fire under ambient wind
    WANG Huaiyuan, DING Yanming, CHEN Wenlu, LU Kaihua, MAO Shaohua
    2022, 32(10):  142-147.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2284
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    In order to better carry out the fire rescue work of aviation kerosene fire, the thermal radiation distribution of aviation kerosene pool fire in the upwind area under the action of the environmental wind was studied, and the relationship between aviation kerosene combustion rate and wind speed and oil pool diameter was discussed. Variation trend of heat radiation flux in upwind area with the wind speed and distance was analyzed. Safety range of thermal radiation in the upwind area under different wind speed and horizontal distance was determined. The results show that the thermal radiation flux in the upwind area decreases first and then increases slightly with the wind speed, and the increasing amplitude decreases gradually with the horizontal distance. In the far-field radiation whose distance to the center of the oil pool greater than three times of the oil pool's diameter, the thermal radiation flux in the upwind area first increases and then decreases with the height, and the maximum value appears when the height from the surface of oil pool is the same as the diameter of it.

    Study on jet fuel explosion characteristics in different volume containers
    DONG Zhangqiang, WANG Yawei, LIU Lijuan, CHEN Xianfeng, YANG Manjiang
    2022, 32(10):  148-153.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2588
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    In order to provide theoretical support for the safe storage, transportation and use level of jet fuel, the variation characteristics of explosion pressure, pressure rise rate, temperature and flame propagation velocity of jet fuel with different mass concentrations in different volume pressure containers were studied experimentally, and the change process of flame structure of jet fuel was simulated by CFD(Computational Fluid Dynamics)explosion simulation software. The effects of container volume and fuel mass concentration on the combustion and explosion characteristics were analyzed. The results show that in the confined space, the explosion parameters of jet fuel first increase and then decrease with the increase of mass concentration, and the fuel mass concentration of the maximum explosion hazard is 104.17 g/m3. At the same time, the pressure generated by the detonation of jet fuel is equal everywhere, and in an equal proportion containers, when the chemical equivalence ratio is close to 1, the maximum flame propagation speed and maximum deflagration pressure of jet fuel are basically not affected by the container volume, but the maximum average pressure rise rate caused by the detonation of jet fuel is inversely proportional to the container size. In the same time, the larger the detonation space, the higher the internal temperature.

    Public safety
    Research on landscaplization of municipal road lighting facilities based on road traffic safety
    YAN Yonghong, YE Zhenguang, YU Kaiyuan, LI Na, ZHANG Bohan
    2022, 32(10):  154-161.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1526
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    In order to improve road lighting safety through an artistry lighting design strategy with limited cost, with lighting design of Chancheng Avenue in Xishui county as an example, influence of lamppost color on drivers' fatigue was studied based on road space enclosed scene and road length threshold by using drivers' visual attention theory. Secondly, effects of LED light-boxes on visual guidance in foggy weather, pedestrian security, and location identification were explored, and influence of road lighting, light source color temperature, and color rendering index on foggy nighttime driving safety was studied. Then, four different working modes for full bright (from dusk till midnight), mid-night, foggy daytime, and foggy nighttime were proposed based on energy-saving requirement. Finally, reliability and effectiveness of all-weather, all-time design strategy were verified through data measurement and user evaluation after project completion. The results indicate high satisfaction from drivers and pedestrians on the uniqueness of the design, safety of the nighttime road lighting environment, and visual guidance of lighting facilities. Colored lampposts relieve drivers' visual fatigue and remind them to reduce speed. Also, the light-boxes effectively provide visual reference for foggy nighttime driving.

    Influence mechanism of built environment around subway station on traffic accident risk
    JI Xiaofeng, QIAO Xin, PU Yongming, LU Mengyuan, HAO Jingjing
    2022, 32(10):  162-170.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2546
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    In order to explore the influence mechanism of subway station passenger flow and surrounding built environment on traffic accident risk within the radiation range, the "5D+S" (5D+Subway) built environment index system was established. An accident risk model based on XG Boost algorithm and a SHAP(Shapley Additive Explanation) attribution analysis model were constructed to explore the nonlinear relationship between built environment and traffic accident risk. Taking Shenzhen as an example, this paper explores the influence mechanism of traffic accident risk around subway stations from two dimensions of weekdays and non-weekdays, and compares it with the elastic network regression model and support vector regression(SVR) model. The results show a nonlinear relationship between the built environment index of subway stations and traffic accident risk. When the density of recreational points of interest (POI) is more than 25 pieces/km2, the traffic accident risk is higher. When the accessibility of shopping malls is between [0.3,0.5]km, the traffic accident risk is higher. The built environment around subway stations has a greater impact on the risk of traffic accidents on weekdays.

    Study on fire spread behavior of surrounding buildings caused by urban extreme explosion accidents
    ZHANG Guowei, LIU Chunyuan, ZHANG Zhiwei, ZHANG Xianghua, YUAN Diping
    2022, 32(10):  171-177.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2033
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    In order to reduce the secondary disasters of surrounding buildings caused by extreme fire and explosion accidents in the city, taking the explosion accident of liquefied petroleum gas storage and transportation device in cities as an example, a simplified explosion model of liquefied petroleum gas storage and transportation device and a radiation ignition model of combustible materials in buildings were established, and an analysis method of fire spread behavior of surrounding buildings caused by urban extreme explosion accidents was put forward. The results show that the urban extreme explosion accident can cause the fire spreading behavior of surrounding buildings, and the thermal radiation generated by the explosion accident will first ignite the flammable materials at the openings of buildings. Subsequently, combustible materials will ignite other combustible materials in the building, and the fire will develop in the trend of t2 fire. When the whole building was over-fired, the fire continued to burn and remained stable. On the whole, the danger arrival time of each floor in the building is relatively close, and the temperature is the main factor affecting the danger arrival time.

    Research on urban fire station layout planning based on model intersection method
    YU Zhijin, XU Lan, CHEN Shuangshuang, GU Yu, YANG Song
    2022, 32(10):  178-185.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2749
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    In order to realize scientific siting of urban fire stations, rationally allocate fire emergency resources, improve fire rescue response speed, and reduce accidents and casualties, the model intersection method was proposed based on the maximizing coverage model and the minimizing facility point model. Firstly, taking Fengdong New City of Xi'an City as the research background, based on geospatial data such as fire risk points of interest (POI), locations of existing fire stations, road networks and fire station layout planning principles, the model intersection point method was applied to optimize the layout of urban fire stations; then the nearest facility point model and service area model were introduced to test the applicability of the model intersection point method, and the POI coverage rate and regional area coverage rate of the new planning site were calculated. The study shows that: compared with the existing fire stations, the POI coverage rate is increased by 10.20% and the regional area coverage rate is increased by 12.43% by using the model intersection method to determine the fire stations. Based on the results of the practicality analysis, 11 new primary fire stations are needed in Fengdong New City after several iterations, and the POI coverage rate and regional area coverage rate can reach 97.66% and 84.80% respectively. Only considering the high-risk places in the study area, the optimized layout of fire stations can cover 98.4% of POI and 96.8% of the regional area within 4min response time.

    FCM-based vulnerability evolution analysis of metro systems under storm disturbances
    ZHAO Luwei, WANG Qing'e
    2022, 32(10):  186-192.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2221
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    In order to prevent subway safety accidents under storm disturbances, an FCM-based root cause analysis method was proposed to assess subway system vulnerability. A causal model consisting of six concepts of human behavior, equipment and facilities, safety management, emergency rescue, environment and vulnerability was constructed to simulate subway system vulnerability within the FCM framework using text mining and expert interviews. The results show that all five factors are strongly correlated with subway system vulnerability, and their correlation magnitudes are safety management > human behavior > emergency rescue > equipment and facilities > environment; equipment and facilities are the most suspicious causes of subway system vulnerability, in addition, attention should be paid to monitoring the emergency rescue reserve and subway operation environment; subway system vulnerability is most sensitive to changes in safety management and personnel behavior. This method can be applied to the prevention of subway safety accidents, so as to improve the safety management of the subway system.

    Research and design of space structure of embedded safety evacuation signs
    FAN Ruiwen, DAI Zhangyin, ZHOU Hui, TIAN Shixiang, JI Tao
    2022, 32(10):  193-200.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1797
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    In order to improve visual appeal of embedded safety evacuation signs, a simulation test of their spatial direction information transmission efficiency was conducted. Influence of their different spatial angles on subjects' choice response time, expected choice conformity and choice confidence was analyzed, and verified through fire drills to get the optimal space angle. Finally, a kind of spatial three-dimensional embedded safety evacuation signs was designed according to research results. The results show that generally the larger the spatial angle is, the larger the visible area there will be, the shorter the choice response time and the higher the expected choice conformity and choice confidence will be. When the angle is 5°, spatial direction information transmission efficiency is the strongest, with the average escape time of participants being the shortest, and proportion of choosing unfamiliar exits increases. The embedded safety evacuation sign with a spatial three-dimensional structure can effectively improve efficiency of fire emergency evacuation.

    Emergency technology and management
    Modified social force model for aircraft cabin emergency evacuation
    YANG Yonggang, WANG Jingjing, SONG Wei
    2022, 32(10):  201-206.  doi:10.16265/j.cnki.issn1003-3033.2022.10.0818
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    In order to accurately evaluate the movement state and evacuation efficiency of passengers in the process of evacuation, make the social force model applicable to the emergency evacuation environment with closed aircraft cabin and dense seats, and simulate the steering and avoidance behavior of passengers in the process of evacuation, a modified social force model based on the aircraft cabin was proposed. This model introduced the steering factor and the avoidance factor, and obtained the comprehensive factor after the weighted average to correct the evacuation speed of passengers. The kinematic-mechanics dynamic equation of the social force model was improved. The correction range was obtained by the theoretical numerical analysis to the key parameters of the modified social force model. Taking a partial cabin of a certain plane as an example, a simulation experiment with 9×6 seats and a single channel was established to simulate the cabin environment. The results show that the simulated evacuation time is consistent with the experimental evacuation time, and the modified social force model is a continuous model of four factors, namely the prediction principle, subjective psychology, movement state and stress state, which can highlight its superiority in the application of emergency evacuation in aircraft cabin.

    Occupational health
    Experimental study on treatment effect of MET on renal injuries in gas explosion
    TIAN Linqiang, LAI Feng, ZHANG Yue, WENG Xiaogang, YAO Sanqiao, REN Wenjie
    2022, 32(10):  207-213.  doi:10.16265/j.cnki.issn1003-3033.2022.10.2123
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    In order to explore characters of kidney injuries caused by gas explosion and treatment effect of MET as well as its possible action mechanism, rat samples were divided into normal control group (NC group), kidney injury caused by gas explosion group (SW group) and kidney injury caused by gas explosion treated with MET group randomly. Then, kidney injury model of rats was built by utilizing actual roadway, renal functions were tested, histological changes of kidney and express changes of apoptosis associated molecular were observed, and those of AMPK and PGC-1α were detected. The results show that kidney injuries are normally expressed as significant congestion and edema in renal corpuscle and kidney tubules along with kidney disfunction. MET can improve renal function and decrease damages probably through activating AMPK and PGC-1α, thus inhibiting apoptosis of renal tubular epithelial cells.

    Development and verification of human thermal response model in high temperature environment
    LIU Donghua, WANG Haitao, YANG Jie, ZHAO Jiangping
    2022, 32(10):  214-221.  doi:10.16265/j.cnki.issn1003-3033.2022.10.1664
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    In order to evaluate the heat strain level of workers in high temperature environment simply and reasonably, a thermal response model of human body in high temperature environment was developed based on the layered principle of human body structure in the two\|node model, by modifying the temperature setting value, metabolic heat production,convective heat transfer coefficient and thermal insulation and vapor resistance of clothing of the original model. According to the test data of 8 different working conditions (normal temperature environment, warm environment and high temperature environment, different clothing, and different labor intensity) in the literature, the prediction accuracy of the model was verified by comparing the simulation results of core temperature and skin temperature with experimental measurements The results show that the modified model works at room temperature. The root mean square deviation of the simulated value of core and skin temperature is less than the standard deviation of the experimental value. Especially in the high temperature environment, the simulated value of the modified model is in good agreement with the experimental value. The maximal difference between simulations and measurements in terms of the core temperature and mean skin temperature is no more than 0.3 and 0.6 ℃ respectively. In the four high temperature working conditions, the prediction accuracy of the proposed model is improved by at least 15% compared with the original two-node model. Especially in the two high temperature working conditions (air temperature 35 ℃, relative humidity 40% and air temperature 38 ℃, relative humidity 25%)of Chinese human body data, the core temperature prediction accuracy of the modified model is improved significantly.