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Table of Content

    28 November 2020, Volume 30 Issue 11
    Safety science theory and safety system science
    Analysis on essential content of hazard
    FU Gui, WU Yali, ZHANG Shijie, YANG Yaodang
    2020, 30(11):  1-5.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.001
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    In order to address inconsistent interpretations of hazard, its essential content was analyzed. Hazard related standards formulated by three technical committees of ISO, TC 262, TC 283 and TC 292 were analyzed, and definition expressions and general ideas in them were studied. Then, the widely recognized implications of hazard were obtained and its essentioal content was summarized based on energy theory and researches of previous scholars. The results show that the term hazard comes from international standards and it actually means causes of accidents. It can be interpreted in three ways as hazardous conditions or situations of things, hazardous substances or energy, depending on which accident causation model is used.
    Safety social science and safety management
    Simulation study on causes of cognitive failure of construction workers' unsafe behavior
    YE Gui, YUE Hongzhe, FENG Xinyi, LI Yuanli, CHEN Liying
    2020, 30(11):  6-12.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.002
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    In order to improve safety management in construction and effectively reduce unsafe behavior of construction workers, seven types of individual factors and four types of environmental factors affecting cognitive process failure of their unsafe behaviors were sorted out. Then, a four-stage causation model of failure was established, and Matlab was used to simulate process of cognitive failure caused by multiple factors. The results show that environmental factors affect workers' cognitive processes by influencing individual factors. Inadequate safety awareness and safety knowledge will lead to cognitive failure in first stage while underestimating risk is a main reason for it in second stage. Failure to choose a safe motivation and lower risk acceptance will lead to cognitive failure in third stage, and failure to perform actions properly leads to that in fourth stage. Moreover, good subjective norms help to correct cognitive bias in second stage of workers' cognitive process.
    Study on construction of risk portrait index system for airline pilots
    WANG Lei, JIANG Yin, TAN Wei
    2020, 30(11):  13-21.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.003
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    In order to quantify risk behaviors of airline pilots and its influencing factors, dimensions of pilot risk portrait were defined through literature synthesis and expert evaluation method. Then, questionnaire of airline pilots risk portrait index system was compiled and implemented among senior pilots of airlines, for which 116 valid samples were obtained. Finally, questionnaire's reliability and validity were tested by exploratory factor analysis(EFA), system effectiveness was examined by confirmatory factor analysis(CFA), and impact importance of each index was determined by adopting effective index combination weighting method. The results show that pilot risk profile, as an assessment method based on big data theory, can effectively quantify personal risks of pilots. And its index system includes six dimensions, namely pilot ability, skills, style, social risk, personality, physical and mental status, and 20 indexes. Among them, risk perception and space perception are the two most important ones.
    Development and application of professional identity measurement model for safety practitioners
    FU Jing, NIE Fangchao, LYU Wei, HE Jingsen, LIU Hong, CHEN Weiwei
    2020, 30(11):  22-29.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.004
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    In order to study occupational psychological state of safety practitioners more clearly and too fully bring into play their professional efficiency, a measurement model of professional identity was developed by using method of Mutually Exclusive Collectively Exhaustive (MECE) based on analysis of career definitions and role differences of safety practitioners between China and foreign countries. Then, data of 144 objects were collected and analyzed and it was found that their professional identity was at a medium level. Additionally, there were significant differences in occupational cognition of latent variables influenced by individual characteristics, such as working years, professional qualifications and technical titles. Different levels of personnel education also led to significantly diverse professional identity of target items, and they were in a positive correlation. It was also found that personals of undergraduate education level received highest professional identity. The research shows that this model can reflect professional identity of safety practitioners from six dimensions, comprehensively measure significance of individual characteristic factor difference on potential variables and target items, as well as indicate influence of educational level on self-cognition and professional evaluation of safety practitioners.
    Psychological symptoms of public under COVID-19 outbreak and improvement of emergency management system
    TIAN Fangyuan, TIAN Shuicheng, LI Hongxia, ZHENG Ya, SHAO Jiang
    2020, 30(11):  30-36.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.005
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    In order to support current and future epidemic prevention and control, between January 31 to February 2, 2020, SCL-90 online questionnaire and snow sampling method were applied to investigate psychological symptoms and performance of 1 060 ordinary Chinese people under level I emergency response after outbreak of COVID-19. The results show that their psychological symptoms during level I emergency response to COVID-19 (P<0.05) are generally worse than that of SCL-90 norms in 1986 and 2018. Three dimensions, obsessive-compulsive symptoms, depression and interpersonal sensitivity, indicate the most severe symptoms, and they were the worst among people over 60 years of age. To stabilize social mentality, government should act as soon as possible to fill up blank of emergency response plan and psychological intervention and psychological aid in emergency management system by taking corresponding measures to reduce people's psychological symptoms.
    Research on unsafe mentality and behavior scales of workers in confined space
    CAO Lulu, LIU Yan
    2020, 30(11):  37-42.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.006
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    In order to explore unsafe mentality and behaviors of workers in confined space, scales for them were compiled from 7 dimensions of paralysis, fluke, rebellion, conformity, shortcut energy saving, boredom and risk-taking mentality and 4 dimensions of personal protective equipment, operation detection, operation ventilation and barbaric operation. Then, collected questionnaires were analyzed by using SPSS25.0 software. The results show that scale items are well distinguished, and overall reliability of scales is 0.953 and 0.966 respectively, while that of each dimension for them is between 0.683-0.887 and 0.857-0.942 respectively. Moreover, KMO values of factor analysis are 0.932 and 0.906, and 7 and 4 common factors extracted could explain 76.102% and 85.014% of variance difference respectively.
    Safety engineering technology
    Mechanism of aqueducts in cold and dry areas under effect of salt-frozen coupling erosion
    GONG Li, KANG Chuntao, WANG Hong, YANG Yiqun, WANG Zhonghui
    2020, 30(11):  43-52.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.007
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    In order to explore service performance of aqueduct in saline cold and arid areas of Northwest China, firstly, finite element simulation analysis of freezing and thawing cycle of aqueduct body was carried out using sequential coupled thermal stress analysis method. Then, freeze-thaw cycle tests were conducted on 3 types of concrete specimens, including reference, antifreeze and early strengthening water reducer, under erosion of Na2SO4 solutions at 4 mass concentrations. The results show that in finite element simulation, as number of freeze-thaw cycles increases, stress and strain values of aqueduct body also increase correspondingly which are mainly concentrated at junction of frozen areas. It is found through tests that quality loss rate and compressive strength loss rate of concrete specimens increase with rise in number of salt freezing, and their damage also gradually intensifies. Under erosion of salt solution at same mass concentration, damage degree of specimen ranks in descending order as antifreeze, reference and early strengthening water reducing agent group. Moreover, salt freezing will cause damage to aqueduct body, and in a long run, it will lead to decline of strength and stability of its structure, therefore affecting service life of water delivery project
    Research on outburst risk prediction and visualization of dangerous zone in driving work face
    LI Zhonghui, MA Yunbo, ZHENG Anqi, HE Shun, WANG Fengzhi, ZHANG Xin
    2020, 30(11):  53-59.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.008
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    In order to improve prediction accuracy of coal and gas outburst risk in driving work face, and improve precise management of dangerous areas, firstly, an optimized grey prediction model of coal and gas outburst was constructed and verified by tested data of 1101 and 1102 track driving work faces of Wujia coal mine. Secondly, average relative error of their outburst risk prediction indexes were calculated to be 2.46% and 1.2% respectively. Then, fuzzy matter-element early warning model for coal and gas outburst was established with four warning levels of "none, mild, moderate, and severe". Finally, a three-dimensional visualization model for outburst was developed with 3D MAX software, which realized visual display of risks in driving work face. The results show that the optimized model improves prediction accuracy of coal and gas outburst, and and the visualization model can directly decide outburst risks in front of driving work face.
    Decision-making method for collision avoidance of ships in confined waters based on velocity obstacle and artificial potential field
    MA Jie, SU Yudong, XIONG Yong, ZHANG Yu, YANG Xin
    2020, 30(11):  60-66.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.009
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    In order to solve the problem that ships were affected by both river boundaries and movement of surrounding ships during collision avoidance process in restricted waters, a decision-making method for ship collision avoidance was proposed, which combined thought of velocity obstacle with theory of artificial potential field. Velocity obstacle method was applied to avoid collision with other ships and static obstacles under constraint of inland river collision avoidance rules. Then, artificial potential field was constructed on navigable waters boundaries to realize collision avoidance. Finally, collision avoidance scenarios such as crossing, meeting and overtaking of ships under straight channel and curved channel were set up, and the method was verified in simulation environment. The results show that the proposed method can help ships make decisions of avoiding obstacles and approaching ships in different directions under constraints of rules, and ensure that collision avoidance path keeps safe distance from boundaries of navigable waters, so as to meet requirement of limited maneuvering in process of collision avoidance.
    Safety evaluation of continuous multi-span aqueduct's demolition blasting based on FAHP method
    ZHANG Zhixiong, YE Xueyun, YIN Zhiqiang, LIU Yang, LAN Shengning
    2020, 30(11):  67-74.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.010
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    In order to effectively control blasting hazard factors, with demolition blasting of continuous multi-span aqueduct's complex structure as research object, a safety evaluation model of its demolition blasting was established by using FAHP method. Then, a triangular fuzzy function was developed to quantitatively describe comparative strength. Finally, weight and membership degree of influencing factors at different levels were obtained by defining corresponding matrix operation, and safety evaluation grade of the object was analyzed. The results show that FAHP quantitatively evaluates safety risk of demolition blasting, and obtains weight and importance ranking of influencing factors. And comprehensive assessment score of the object is 75.18, rated as "relatively safe". Blasting design parameters are optimized, and construction quality of drilling, breakpoint location and pretreatment is improved.
    Dynamic simulation of bus seats and model improvement
    TANG Youming, TAN Weifeng, ZHANG Yi, WANG Ping
    2020, 30(11):  75-81.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.011
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    In order to have newly produced bus seats meet mandatory requirements of dynamic testing regulation GB13057-2014, a 3D mathematical model and finite element model of bus seats for a company was established by adopting explicit finite element software LS-DYNA 3D. And through coupling it with Hybrid III 50% male dummy model, a dynamic simulation model of seats was obtained. Then, test results were analyzed and simulation model was verified by using occupants' injury peak, WIC, dynamic responses and posture, and deformation mode of seats. Finally, the model was improved by changing sponge stiffness of seat back and light-weight seat foot design based on cost considerations. The results show that occupants' injury index and seat deformation are in good agreement in test and simulation, and error of WIC value is less than 4.3%. Moreover, light-weight design has obvious effects as seat foot weight reduces 31.8% and WIC value decreases 11% in case of an increase of 2.8% in cost. Weakening main components' strength and reducing sponge stiffness of seat back can effectively decrease occupants' injury level in rear seats on the basis of considering international acceptance standard of deformation range and seat comfort.
    Study on behavior and control of droplets in high-temperature counter gas
    HE Mingli, ZHANG Guang, HU Shaohua, WANG Cheng
    2020, 30(11):  82-87.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.012
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    In order to promote penetration properties of water mist, its motion in high-temperature counter flow was studied. Firstly, a motion and heat transfer model of a single droplet was established which was utilized to analyze effects of counter gas and high temperature on velocity and penetration distance of droplets in detail. Then, control effects of co-flow jet on droplets were evaluated. Finally, a method to design a co-flow jet water mist fire extinguishing system was proposed. The results show that it is difficult to effectively increase penetration distance of small droplets by increasing operating pressure at sprinklers, and moreover, droplets are easily entrapped by counter gas. A co-flow jet can help reduce velocity attenuation and increase penetration distance. Furthermore, utilization efficiency of water mist can be improved by a co-flow jet due to decrease of droplet vaporization in flue gas layer and increase of droplets entering flame zone. Structure and operation parameters of a co-flow jet water mist fire extinguishing system can be basically determined according to the design method.
    Research on safety monitoring system of tower crane based on FEM and IoT
    HE Guanghui, LI Xiaowei, LI Xinkui, SHEN Zhiyong
    2020, 30(11):  88-94.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.013
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    In order to remotely monitor operation safety of tower cranes, and to reduce risk of monitoring workers, IoT technology was applied to obtain real-time sensor operation data of tower cranes, and a FEM-based real-time SMS for its structure was developed. Then, its dynamic structure mesh was updated automatically in real time on local computer by SMS based on sensor data collected by mobile communication network. Finally, linear equations governing operation process were solved by Cholesky solver, and a comparison between remote monitoring results and filed measurements was made for stress and deflection of tower crane members. The results show that solving efficiency of Cholesky is much better than that of Gauss solver with its time cost for each computation less than 0.5 s. And analysis errors of SMS pertaining to deflection and strain results are respectively less than 14% and 12%, which indicate that SMS is reliable and accurate.
    Similar experimental study on non-linear oxidation heating up process of coal in dynamic gob areas
    ZHOU Peiling, YUAN Fei, ZHAO Pengxia
    2020, 30(11):  95-100.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.014
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    In order to explore deeper into oxidation heating characteristics of residual coal in gob areas, a similar experimental platform was built based on heat and mass transfer model which was established by volume average method. Nonlinear heating up process of such residual coal was studied and similar experiment results were verified by field test data. The results show that high temperature area mainly concentrates on air inlet side, and it will move forward along with advancing of working face while temperature in gob areas increase exponentially over time. Advancing speed of working face is a main factor that influences oxidation heating up process, the faster it is, the smaller heating rate of gob will be, and there is a negative exponential reduction relationship between it and maximum temperature in gob. Meanwhile, along with its increase, depth of maximum temperature point increase gradually. According to fitting curves of characteristic points' heating up in gob, it is also found that experimental results are basically consistent with that of field experiment, which proves rationality of similar experiment.
    Effects of gas volume fraction on venting features of 90° elbows after explosion
    HUANG Qiang, MU Chaomin, WANG Yajun, ZHOU Hui, LI Zhongqing
    2020, 30(11):  101-107.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.015
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    In order to explore propagation characteristics of gas with different volume fractions in explosion chambers and venting characteristics of 90° elbows, a gas venting experiment was carried out. Numerical simulation and experimental research were used to analyze propagation process of explosive blast in system, and variation characteristics of blast and flame size of six groups of gas at different volume fraction were explored. The results show that propagation of explosion shock wave in pipeline is in the form of multiple overpressure, and its peak overpressure gradually decreases. Additionally, peak overpressure and its rising rate in explosion cavity have the same change trend, and both reach maximum when gas volume fraction is 9.5%. At the same position in 90°elbows, peak overpressure rising rate generated by different volume fractions of gas is in a sawtooth shape. When it is 5.8%-11.0%, flame size varies in a sawtooth shape along with propagation distance. When at 5.8% and 6.5%, flame is extinguished before 90°. When between 5.8% and 11%, peak overpressure and flame size are significantly attenuated after pipe is bent at 90°
    Weld defect detection and identification method of typical equipment in oil-gas station
    WU Linyu, LIANG Wei, SHA Duolin
    2020, 30(11):  108-113.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.016
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    Based on three-coil detection technology under bidirectional excitation, a method to identify weld defect types building on weld state identification and feature subset optimization was proposed in this paper. Firstly, characteristics and complexity of weld signals were analyzed by utilizing non-linear characteristic analysis method and Lemper-Ziv complexity value so as to identify weld category. Then, extracted features were reduced in dimension based on improved maximum relevance minimum redundancy feature selection method. Finally, optimal feature subset under different weight factors were used as input of SVM to identify defects of tested signals in oil-gas station. The results indicate that Lemper-Ziv complexity-based distribution can help accurately distinguish weld types. And it is verified by tests that recognition method based on feature subset optimization has high recognition accuracy for both longitudinal defects and transverse defects of welds, and its overall accuracy can reach as high as 83.33%.
    Public safety
    Influence of multi-hole obstacles at different locations on premixed flame's propagation
    CHENG Fangming, CHANG Zhuchuan, GAO Tongtong, JI Pengfei, LUO Zhenmin
    2020, 30(11):  114-120.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.017
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    In order to understand propagation mechanism of premixed flame, influence of multi-hole obstacles at different locations in semi-closed pipes on flame propagation was studied through experiments. Then, propagation process was recorded by high-speed cameras, and shape and dynamic changes of flame before and after passing through obstacles were analyzed. Meanwhile, its edges were detected by using boundary operator, pixels were calculated, and folds were measured. The results show that compared with cases without obstacles, multi-hole obstacles intensifies flame front folds, which therefore increases pixel value of its edge and shortens time to spread in pipes. In addition, it was found that the farther obstacles are away from ignition position, the more significant impact they will have on flame. And compared with cases of zero obstacle, when it is at 100 mm position, maximum transmission speed of flame is increased by 54%, transmission time is reduced by 76.2%, and flame edge pixel increased by 52.7%.
    A dynamic assessment method for consequences of explosion accidents on offshore platforms
    YANG Dongdong, CHEN Guoming, SHI Jihao, DAI Ziliang
    2020, 30(11):  121-126.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.018
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    In order to scientifically evaluate consequences of explosion accidents in offshore platforms, a dynamic assessment method was proposed considering disaster evolution induced by leak and emergency evacuation of operators. With process area of lower deck in an offshore platform as example, and effects of emergency shut down (ESD) system and blowdown system on dangerous gas profile being considered, explosion simulation was conducted by introducing ignition source. Then, emergency evacuation trajectories were determined with help of grid-based concept and emergency response sequence. Finally, dangerous area was identified and classified based on maximum overpressure loads in real-time position of operators, and simulation results were compared with those obtained from "static" method. The results show that the proposed method gives a better consideration of accident evolution process and emergency evacuation and the latter can greatly reduce dangerous area of explosion but may aggravate consequence severity of operators in local area.
    Identification of black spots in urban roads and spatiotemporal patterns mining
    WU Peijie, MENG Xianghai, CAO Mengdi
    2020, 30(11):  127-133.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.019
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    In order to identify black spots and their spatiotemporal evolution patterns in urban road networks accurately, rapidly and microcosmically, and to effectively reduce frequency of traffic accidents, a crash data mining method based on space-time cubes was proposed. Firstly, selection method of important parameters in construction of space-time cubes model was studied, and spatiotemporal black spots in urban road network were identified by "space-time cubes + cumulative frequency curve method". Then, their spatiotemporal dynamic evolution patterns were obtained based on emerging hot spot analysis method. Finally, the space-time cubes method was compared with quality control method, empirical Bayesian method and kernel density estimation from aspects of their advantages, disadvantages and application scopes. The results show that space-time cubes method and kernel density estimation are applicable to identification of black spots at the meso and micro scale while emerging hot spot analysis method can be utilized to obtain their spatiotemporal evolution patterns
    Research on building fire insurance premium rate based on improved combination weighting method
    MA Aidi, YUE Zhong, SUN Baoping, CHEN Dawei
    2020, 30(11):  134-140.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.020
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    In order to address problems of unknown fire risk index weight and rough fire insurance rate determination method for public buildings in China, a targeted fire risk assessment model was established considering factors such as structural design of insured subjects and fire risk management. Secondly, ideal point theory was utilized to improve combination weighting method, and fire insurance premium rates were determined by using assessed fire risk coefficients based on characteristics of modern public buildings and calculation principle of the rates. Finally, with 3 large department stores in Beijing as an example, improved method was compared with linear weighted and multiplication normalization methods before its rate was calculated. The results show that improved combined weighting method effectively reduces uncertainty of existing method in subjective judgment coefficients, and minimizes distance between subjective and objective weights and ideal point. It is suitable for improving existing actuarial methods of fire insurance rates with calculated result of target premium being consistent with its fire risk status.
    Analysis on injury severity of pedestrian in motor vehicle-pedestrian accidents
    DONG Aoran, WANG Changshuai, QIN Dan, ZHU Tong, XU Ting
    2020, 30(11):  141-147.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.021
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    In order to explore factors affecting pedestrian's injury severity in motor vehicle-pedestrian crashes, 6 101 cases of such crash accidents in a city were investigated. 19 variables were selected from four aspects, including human, vehicles, roads and environmental conditions, and a pedestrian injury severity analysis model was established by using partial proportion odds model. Then, influence of significant variables on injury severity was analyzed quantitatively through elasticity analysis. The results show that 12 variables have a significant impact on pedestrian's injury severity in these crashes, including drivers' gender and age, pedestrian's gender and age, vehicle types, pavement structure, road types, time of accident, whether there is a traffic signal control, visibility, lighting conditions and terrain. Among them, variables like drivers' gender and age meet the proportional odds assumption, while those like pavement structure do not.
    Technology and engineering of disaster prevention and mitigation
    Analyses on formation conditions and triggering mechanism of Atabad landslide
    CHEN Wentao, YANG Zhiquan, ZHU Yingyan, ZHANG Zhiwei, ZHANG Jie, LUO Zhigang
    2020, 30(11):  148-155.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.022
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    In order to study strarting theory of huge ice-wedge landslide, its formation conditions and triggering mechanism were analyzed with Atabad landslide as research object. Field investigation was conducted on classic geomorphy, climate, engineering geology, hydrogeology, seism and neotectonic movement in Atabad village, and triggering mechanism was obtained through theoretical analyses. The results show that landslides in Atabad are caused by special geological factors of alpine high altitude area, including geomorphy, climate, engineering geology, hydrogeology, seism and neotectonic movement. The landslide on January 4, 2010 was induced by groundwater crack action and repeated frost heaving of ice wedge, while several secondary landslides which occurred after that were mainly developed by freeze-thaw actions.
    Improvement and application of trapezoidal fuzzy fault tree prediction algorithm
    ZHANG Yuanyuan, SUN Lin, LIU Ming
    2020, 30(11):  156-161.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.023
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    In order to address deficiencies of linear approximation of basic events' multiplication results in traditional trapezoidal fuzzy fault tree prediction algorithm, an improved algorithm was proposed based on both cut set theorem and representation theorem of fuzzy mathematics. Then, with fire accidents in a coal mine as an example, accident consequence was simulated in five cases, and furthermore, reliability and adaptability of the new algorithm was verified according to both traditional and improved trapezoidal fuzzy fault tree prediction methods. Finally, approximate and accurate membership degree graphs were drawn, and approximate and accurate fuzzy importance degree of electrical equipment explosion events were calculated. The results show that the new algorithm features good adaptability, and its application in five cases can all improve prediction accuracy. The bigger blindness and core of basic events' trapezoidal fuzzy number and the longer data sequence are, the more significant improvement new algorithm will achieve.
    Design and application of test device for tailings erosion under sand flow
    CAI Hai, WU Shangwei, WU Dongming, JING Xiaofei, WANG Wensong, KANG Qinrong
    2020, 30(11):  162-167.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.024
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    In order to explore gradual failure and erosion characteristics of overtop of tailing dam, a tailing erosion test device under sand flow was developed based on dynamic theory of sediment. Then, height change of tailing sample before and after erosion was observed with horizontal pipe made of transparent acrylic plate, and water flow was continuously changed through frequency converter. Meanwhile, erosion height and time of sample before and after erosion were recorded with Vernier caliper and high-speed camera. Finally, erosion rate of tailings with different mass fraction (0%, 3%, 6%, 9%) was measured with test device, and erosion characteristics of sand bearing water flow and velocity on tailings were analyzed. The results show that erosion rate of tailings reaches its maximum under action of clean water, and it will decrease along with increase of sand content in water flow. This conclusion is consistent with previous research results, which verifies feasibility and effectiveness of the test device.
    Emergency technology and management
    Bi-objective optimization of emergency material game allocation considering limited rationality
    ZHENG Yanhui, ZHU Changfeng, WANG Qingrong, LIU Sinan, MA Yangyang
    2020, 30(11):  168-174.  doi:10.16265/j.cnki.issn1003-3033.2020.11.025
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    In order to improve emergency management in early stages of a large-scale sudden disaster, and to effectively and reasonably allocate emergency materials to each affected point, prospect theory was applied to describe people's psychological satisfaction with supplies' distribution considering shortage of emergency materials, complexity of allocation process and people's competitive psychology under limited rationality. At the same time, in view of time delays of material transportation caused by secondary disasters, a bi-objective optimization allocation model was constructed in non-cooperative game environment to minimize emergency material transportation time and maximize overall psychological satisfaction at each affected point. Finally, NSGA-Ⅱ algorithm was designed to solve the model before Pareto solution set was obtained, and ideal solution was selected as satisfactory solution. The results show that the model and algorithm are effective and convergent, and satisfactory solution obtained by the model is more efficient and fair
    Construction of risk potential map of toxic gas diffusion considering influence of multiple factors
    LYU Wei, JIANG Cuiling, JIANG Yajuan, ZHAO Caihong, WANG Jinghui, LI Jiawei
    2020, 30(11):  175-181.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.026
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    In order to analyze leakage and diffusion risk of hazardous chemicals during transportation, with influence of multiple factors taken into consideration, including uncertain wind condition, position of diffusion source and surrounding social environment, location of diffusion source was determined by scenario hypothesis. Then, population density distribution was characterized based on building distribution and population information, and possibility of wind condition was quantified by wind direction map. Finally, a construction method of risk potential map of toxic gas diffusion was proposed for comprehensive evaluation of possible influence area, and a case of liquid chlorine leakage and diffusion was analyzed by using scenario hypothesis. The results show that possible influence range of toxic gas diffusion can be more comprehensively evaluated with uncertainty of wind direction being considered. And regional population density can be quantitatively characterized by utilizing information of building distribution and number of people it can accommodate.
    Occupational health
    Numerical simulation of skin temperature of hands in low-temperature environment
    HE Yan, YANG Jie
    2020, 30(11):  182-187.  doi:10.16265/j.cnki.issn 1003-3033.2020.11.027
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    In order to evaluate cold stress and injuries of hands, develop high-performance gloves, and improve work efficiency of first responders, from perspective of multi-segment and multi-layer modeling, hand was divided into 7 segments including thumb, index finger, middle finger, ring finger, little finger, palm and dorsum, and each segment included four layers which were skin, fat, muscle, and core layer. Then, a hand thermal response model was proposed to simulate skin temperature. Finally, simulations were compared with measurements in literature so as to validate prediction accuracy of the model. The results indicate it shows great accuracy in palm and dorsal skin temperature, and simulations are comparatively consistent with measurements with a maximum discrepancy of 3.6 ℃ and 2.4 ℃, respectively. Moreover, decrease rate in skin temperature of middle finger and ring finger are the highest, followed by thumb while index finger and little finger are the lowest.