China Safety Science Journal

Human cognitive reliability model of marine floating nuclear power plants

ZOU Shuliang, HUANG Binhai, LI Shufan

2020, 30(1): 1-6. doi:10.16265/j.cnki.issn1003-3033.2020.01.001

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In order to guarantee safe operation of marine floating nuclear power plants, human factor reliability of them is analyzed by using HCR model. Firstly, influence of external factors such as ocean microclimate, noise and hull motion on operating speed and accuracy was analyzed and quantified, and HCR model was modified. Then, with LOCA of marine floating nuclear power plants as an example, behaviors of people involved in the accident and their handling process were analyzed before values of calculation parameters were obtained according to accident scenarios. Finally, failure probability of operator's recognition of and response to abnormal LOCA signals was calculated. The results show that calculated results are in good agreement with actual situation, and the modified HCR model has greater operability.

Relationship between work stress and behaviors of safety supervisors in mines

AN Yu, LI Jianfei, LI Hongwei, QI Minghui, XU Surui, TONG Ruipeng

2020, 30(1): 7-13. doi:10.16265/j.cnki.issn1003-3033.2020.01.002

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In order to improve safety performance in coal production, with safety supervisors of coal mines taken as research object, analysis is conducted on relationship between their work stress, safety behaviors, and managerial self-efficacy. Firstly, hypotheses were put forward and a model was constructed based on literature review. Then, investigation was carried out on 8 coal mines in Shanxi Province, and 308 valid questionnaires were collected. Finally, correlation was analyzed with SPSS software, and mediation effects of managerial self-efficacy were tested by using SEM. The results show that supervisors' pressure of safety responsibility is positively related with safety behavior while pressure from work environment, that of work tasks, internal organization, role conflict and career development are negatively related with it. And it is also found that managerial self-efficacy plays a mediating role in relationship between work stress and safe behaviors.

Research progress and practical application of safety psychology from perspective of new engineering

TONG Ruipeng, LI Hongwei, ZHANG Na, XU Surui, AN Yu

2020, 30(1): 14-20. doi:10.16265/j.cnki.issn1003-3033.2020.01.003

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In order to explore current research and application progress of safety psychology, and to further make up for shortcomings of its disciplinary contents from a perspective of new engineering, firstly, similarities and differences between safety psychology and OHP were compared through literature review, and its development history, models and methods, research objects and contents were sorted out. Then, through analyzing theoretical contents and problems in practice based on research results and psychological health policy, a vision was proposed that integrates OHP, safety ergonomics and practical interaction, and a mind map of this discipline was constructed. Finally, deficiencies of safety psychology in aspects of theoretical research, interventions as well as recognition degree were obtained. The result shows that safety psychology is similar to OHP, and its contents will be supplemented by a variety of practical application under a perspective of new engineering and thorough studies on it could be enhanced by a combination of “industry, education, research and application” to make up for its deficiencies.

Numerical simulation of airflow temperature and humidity for partly wet roadway model

ZHANG Xiaoming, HUANG Liang, WANG Yongjun, XIE Pengfei, SASAKI Kyuro

2020, 30(1): 21-26. doi:10.16265/j.cnki.issn1003-3033.2020.01.004

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In order to study different influences caused by uniform wet surface and partly wet surface on temperature of surrounding rocks and roadway walls and to accurately predict airflow temperature and humidity in wet roadway, a numerical calculation model for heat conduction of surrounding rocks and airflow temperature and humidity was constructed based on theory of three dimensional temperature field. Then, uniform wet surface model (UWSM) and PWSM were simulated, and influences of parameters on airflow temperature and humidity were discussed under different simulation conditions. The results show that rock and airflow temperature distribution calculated by three dimensional heat conduction model under partly wet condition are more reasonable. The proposed method of determining correction factors of wetness based on wet area-ratio can improve prediction accuracy of temperature and humidity in large-scale ventilation networks.

Spatial-temporal evolution characteristics and influencing factors of work safety level in construction industry

ZHENG Xiazhong, TONG Liyang, CHEN Guoliang

2020, 30(1): 27-34. doi:10.16265/j.cnki.issn1003-3033.2020.01.005

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In order to improve work safety of construction industry correspondingly at a macro level, it is essential to clarify its spatial-temporal evolution and influencing factors. Firstly, an analysis model of work safety level based on DEA-GCE was presented under window analysis framework. Then, it was applied to evaluate work safety level of construction industry between 2012 and 2017 in provinces and regions of China, and spatial-temporal evolution and influencing factors were identified and explored by using cluster analysis, exploratory spatial analysis and multiple regression analysis methods. The results show that work safety level of China's construction industry presents four temporal evolution characteristics, namely low level maintaining type, high level stable type, fluctuatingly decreasing type and fluctuatingly improving type, and its spatial agglomeration is obvious with an increasingly enhanced trend of positive spatial correlation. Among all factors, local economic development, construction as a proportion of GDP, that of state-owned construction assets of total assets, survey and design, number of supervisors and government's investment in supervision are major influencing factors for work safety level,and all elements are positively correlated with that except from the proportion of state-owned assets.

IFOA-ELM prediction model of coal and gas outburst based on preprocessing

WEN Tingxin, JIN Lulu

2020, 30(1): 35-41. doi:10.16265/j.cnki.issn1003-3033.2020.01.006

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In order to quickly and accurately predict danger of coal and gas outburst, an IFOA-ELM prediction model based on preprocessing is proposed. Firstly, some measured data of Pingdingshan Eighth Mine was preprocessed, GREA, combining GRA with EWM, was used to remove less influential factors and PCA method was adopted to further simplify factors. Then a coal and gas outburst risk prediction model was constructed, and adaptive step size update strategy and population fitness variance strategy were introduced based on fruit fly optimization algorithm (FOA) to design IFOA which was further utilized to optimize ELM input layer weights and hidden layer thresholds and train and predict preprocessed sample data as well as compare it with that of other models. The results show that prediction results of IFOA-ELM model based on pretreatment completely match with actual results, and its prediction effect is significantly better than that of the unpreprocessed one. And classification accuracy and recall rate of preprocessed IFOA-ELM model are both 100%, obviously higher than other comparison models.

Combined reinforcement technology for water scour damaged piers of heavy-haul railway

CHEN Shuli, LIU Dunli, TIAN Bo, XU Hongwei

2020, 30(1): 42-47. doi:10.16265/j.cnki.issn1003-3033.2020.01.007

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In order to prevent destruction of pier foundation caused by flood scouring which will further affect bearing capacity and operation safety, a set of technical method combining supplementary pile foundation and foundation reinforcement method was proposed based on theoretical analysis and field test of flood scour disease of a heavy load railway pier. Then, a step-by-step implementation plan was drafted and applied in practical projects. The results show that static indexes, such as bearing capacity of single pile, displacement of pier top and earth pressure at pile side, are improved obviously after reinforcement, transverse vibration amplitude of bridge pier and span structure is markedly lower, and lateral vibration frequency of pier increases 5 times. Foundation stiffness and bearing capacity of pier and abutment are improved significantly.

Dynamic reliability analysis of vertical cryogenic tank under wind load

LIU Ming, ZHENG Yaming, DUO Yili, ZHAO Chao

2020, 30(1): 48-52. doi:10.16265/j.cnki.issn1003-3033.2020.01.008

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In order to study dynamic reliability of storage tank structure under random wind load, with a 300 m³small and medium-sized vertical cryogenic tank as research object, pulsating wind speed time series and pulsating power spectral density function of wind load were numerically simulated by using AR model. Then, a three-dimensional finite element model of storage tank was established by ANSYS, and dynamic analysis of the tank was carried out to calculate random response value of storage tank structure before all digital features required for its dynamic reliability under random wind load were obtained. Finally, dynamic reliability was calculated by using first transcendence mechanism. The results show that under the condition of maximum wind speed of 26.8 m/s 10 m high in 50 years, structure displacement and velocity response amplitude are relatively large and storage tank is comparatively sensitive to low frequency vibration when vibration frequency is 0.83 Hz. With the increase of service life, dynamic reliability of storage tank structure presents a negative exponential decline trend, which will drop to 71.46% when designed service life of storage tank reaches 25 years.

Early warning indicators for safety monitoring and control of super high-rise ICCP

ZUO Zibo, PAN Xi, HUANG Yulin, WANG Xiaolin, ZHANG Longlong

2020, 30(1): 53-60. doi:10.16265/j.cnki.issn1003-3033.2020.01.009

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In order to accurately monitor operation safety of ICCP, internal relations and differences of basic principles for safety monitoring between ICCP and super high-rise buildings were discussed. With twenty safety monitoring projects for super high-rise buildings as examples, including Burj Khalifa, Shanghai Center and Taipei 101, statistical analysis was made for key monitoring items and indicators during construction and operation periods, and these items were graded according to importance. Then, based on statistical analysis results and a large number of ICCP practices, ICCP key monitoring items and warning indicators were presented, which was verified by field test of a high-rise building with three asymmetric connected towers, 368 m high at maximum. The results show that ICCP monitoring indicators are in a reasonable range, and levelness of platform frame is finally controlled within 20 mm. And proposed ICCP warning indicators can help improve security capability and informationization of super high-rise building construction.

Heated trace features of galvanized steel plate coated with polyester

JIN Jing, YAO Zijia, LIU Ling, ZHANG Jinzhuan, ZHOU Guangying, WANG Ping

2020, 30(1): 61-65. doi:10.16265/j.cnki.issn1003-3033.2020.01.010

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In order to study heated trace features of polyester coated galvanized steel sheet, thermoplastic acrylic coated galvanized steel sheet was selected as research object, and features of its heated trace under different temperature and duration was discussed based on thermogravimetric analysis of its coating. The results show that the coating obviously undergoes pyrolysis carbonization when temperature rises to 360 ℃, resulting in mass loss of steel. With cracking and shedding of the coating at temperature between 410 ℃ and 590 ℃, steel mass further decreases. As galvanized layer exposes and oxidizes at 600 ℃, steel plate is exposed and oxidized, resulting in recovery of mass, and multi-layer and non-uniform heating traces are presented for the whole plate caused by oxidization of its parts at different degree. Comparatively, influence of heating duration on traces is more significant at higher temperature.

Study on influencing characteristics of vertical penetrating crack on instability and breaking of hard roof

WANG Haiyang, ZHAO Shulei, LIU Jialiang, XIA Binwei, LI Shoulong

2020, 30(1): 66-72. doi:10.16265/j.cnki.issn1003-3033.2020.01.011

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In order to reveal influencing characteristics of vertical penetrating crack on instability and breaking of hard roof, theoretical analysis was conducted on breaking span of such hard roof based on analysis of vertical crack's morphology caused by hydraulic fracturing. Then, deformation failure characteristics and damaged area distribution of hard roof were studied by means of numerical simulation. The results show that the breaking span of hard roof is shorter than its initial limited span when open vertical penetrating crack is in certain range. But if crack is closed, two bulks of the hard roof will deflect to crack face and shear slip will take place along it, which makes hard roof easier to break. The tension-compression destructive effect in biting point area of rotary blocks is a main reason for local buckling, greater rotating degree and roof breaking. The smaller normal stiffness coefficient of vertical crack face is, the easier roof breaking will be. Hard roof with open vertical penetrating crack instead of closed one is more likely be deform and break.

Research and application of hydrogen sulfide control technology with enclosed air curtain in fully-mechanized excavation face

WANG Wei, JIA Baoshan, QI Yun

2020, 30(1): 73-80. doi:10.16265/j.cnki.issn1003-3033.2020.01.012

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In order to avoid influence caused by hydrogen sulfide emission on production safety during mining process of fully-mechanized excavation faces, a new technical plan with wind-curtain ventilator to seal these faces was put forward based on site measurement and analysis of hydrogen sulfide distribution law of No.8116 fully-mechanized excavation face in Jinniu Mine, aiming at preventing its overflow. Secondly, a mathematical model of wind-curtain dust-catching ventilator in confined space was established according to potential superposition principle and fluid mechanics theory. Finally, an air curtain jet velocity attenuation experiment was conducted to verify its rationality. The results show that wind curtain velocity will attenuate abruptly in early stage and then slowly later as jet distance grows, and theoretical wind velocity calculated through this model is basically consistent with measured one. In space sections where air curtain jet needs to be sealed, measured wind speed is all above 2.7 m/s, which helps prevent hydrogen sulfide from leaking. Through field installation and application, concentration of hydrogen sulfide at driver's position can be reduced from 72.5×10^-6 to 6.3×10^-6, thus achieving good control effect of hydrogen sulfide.

Characteristic analysis on leakage-burning coupling of LNG tanker

XIANG Li, XIE Qiyuan, ZHANG Jie, LU Qizhao, ZHOU Feng

2020, 30(1): 81-86. doi:10.16265/j.cnki.issn1003-3033.2020.01.013

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In order to analyze evolution of accident chain of "leakage-burning-heat feedback-temperature/pressure increase-stronger leakage", which is triggered by ignition of fuel leaked from LNG tanker, a coupling model of leakage-burning was developed based on typical situation in China. And effects of leakage phase, filling ratio and aperture on leakage accident development were analyzed. The results show that pressure in tanker might increase sharply and explode caused by positive feedback between leakage rate and burning heat flow at the leakage stage of liquid. It would be more dangerous in early leakage stage for low filling ratios while peak pressure would be higher for high filling ratios. The peak pressure of tanks normally decreases along with increase of aperture within certain range and at certain filling ratios.

Pipeline defect recognition method based on CEEMD-FCM

WANG Chaoqun, LIANG Wei, LIANG Xiaobin

2020, 30(1): 87-93. doi:10.16265/j.cnki.issn1003-3033.2020.01.014

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In order to improve identification accuracy of pipeline defects, CEEMD-FCM model is proposed by using CEEMD and FCM clustering algorithm. Firstly, based on analysis of defect signal waveform features, particle swarm optimization algorithm (PSO) was introduced to improve wavelet threshold de-noising method, and noise reduction of pipeline defect signals was realized. Then, defect signals were decomposed by CEEMD, and characteristic parameters of defects were extracted through principle of energy entropy. Finally, FCM was optimized by simulating annealing algorithm (SA) and genetic algorithm (GA) to complete classification of pipeline defects. The results show that comprehensive identification accuracy of the proposed identification method reaches 87.5%. It can achieve accurate identification of defect modes in petrochemical industry, therefore ensuing safe operation of pipeline and reducing accident rates.

Influence of ignition position and opening ratio on explosion pressure in pressure-relief pipe

XU Chuang, CHEN Xianfeng, DAI Huaming, HUANG Chuyuan, ZHAO Qi, WANG Yujie

2020, 30(1): 94-100. doi:10.16265/j.cnki.issn1003-3033.2020.01.015

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In order to study the influence of different initial conditions on the explosion pressure of natural gas, an experimental system of a spherical vessel connecting to pressure relief pipe was built. By the pressure sensors placed in spherical vessels and pressure relief pipes, the characteristics of explosion pressure were obtained at the ignition position of 0, 2.7 and 4.7 m from spherical vessel center and the opening ratio of 0%, 25%, 60% and 100%. The results show that when the ignition position is located at 2.7 and 4.7 m, the peak pressure and pressure increase rate in spherical vessel are significantly larger than the values after ignition at 0 m, that setting the pressure relief port obviously reduces the peak pressure in spherical vessels, but with the increasing of the opening ratio, the decreasing of peak pressure is not obvious, that the peak pressure at the end of the pipe is maximum at the ignition position of 0 m without the relief port while it is maximum at the ignition position of 4.7 m with a pressure relief port, and that when the ignition position is at 0 m, the maximum pressure increase rate at the end of the pipe is less than that at the ignition position of 2.7 and 4.7 m.

Influencing factors and depth prediction model of pre-mixed abrasive water jet cutting

GUO Jiahe, QI Xuyao, WANG Dong, ZHU Guoqing, CHEN Liangzhou

2020, 30(1): 101-106. doi:10.16265/j.cnki.issn1003-3033.2020.01.016

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In order to address deficiencies of existing forcible entry tools in cutting performance and applicability as cutting is one of the effective ways for emergency rescue, study was conducted on influence degree of pre-mixed AWJ on demolition and cutting of concrete, and an optimized method was proposed. Then, effects of process parameters such as jet pressure, traverse speed, impact angle, and target distance on cutting performance were studied mainly by single-factor experiments and orthogonal experiments. Finally, a prediction model of cutting depth was obtained through multiple linear regression analysis. The results show that cutting depth varies significantly due to influence of different parameters. It increases along with the increase of jet pressure, decrease with that of traverse speed while increase and then decreases in that case of target distance with the optimal target distance at 4mm. As impact angle fluctuates, the optimal impact angle is 80°. And these parameters rank as jet pressure, traverse speed, target distance according to their influence degree from big to small on cutting depth.

Study on optimum mass fraction of aluminum hydroxide in compound powder

LI Hangchen, GUO Xinxin, LI Shunchao, ZHANG Han, HUA Min, PAN Xuhai

2020, 30(1): 107-113. doi:10.16265/j.cnki.issn1003-3033.2020.01.017

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In order to develop efficient dry powder extinguishing agents, a novel compound powder extinguisher was prepared with ultra-fine ABC dry powder as base material and aluminum hydroxide as additive. Then, through experiments, its suppression efficiency and inhibition effects on toxic gases were measured at different mass fraction of aluminum hydroxide. The results show that as mass fraction of aluminum hydroxide rises from 0 to 10%, drop rates of temperature and flame height both increase first and then decrease while minimum extinguishing concentration (MEC) and extinguishing time decrease first and then increase. Fire-extinguishing effect and toxic gas suppression performance would be the best when mass fraction reaches 4%. Furthermore, thermogravimetric (TG) analysis results demonstrate that aluminum hydroxide can enhance thermal decomposition rate of compound ultra-fine dry powder, resulting in better fire-fighting efficiency.

Characteristics of CMC/ZrCit/GDL fire extinguishing gel used for mines

DONG Kaili, WANG Junfeng, LIANG Zewen, SHI Qi

2020, 30(1): 114-120. doi:10.16265/j.cnki.issn1003-3033.2020.01.018

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In order to prevent and control spontaneous combustion of coal, a new fire-suppression gel is developed for mines, which consists of sodium carboxymethylcellulose (CMC), zirconium citrate (ZrCit) and gluconic-δ-lactone (GDL). Firstly, gelation time and viscosity of gel at different ratios were tested, and suitable ratios for fire preventing and extinguishing in different situations were selected. Then, its resistance performance and effects on weight loss and heat release of coal were analyzed through programming temperature and thermogravimetric (TG) experiments. The results show that addition of gel suppresses spontaneous combustion of coal. Gelation occurs during penetration, and it is cemented to coal surface and fills up cracks. When being heated to 180 ℃ within same time, water losses about 30% weight more than No.32 gel, which indicates that gel has strong water retention and good thermal stability. It is demonstrated by fire extinguishing simulation experiments that using gel for extinguishing fire can cool temperature quickly and will not cause re-ignition easily.

Influence of coalification on microstructure characteristics of coal surface

LIU Huifang, SONG Dazhao, HE Xueqiu, TIAN Xianghui, LOU Quan, WANG Weixiang

2020, 30(1): 121-127. doi:10.16265/j.cnki.issn1003-3033.2020.01.019

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In order to study influence of coalification on microstructure characteristics of coal, with coal at three different metamorphic grades selected as samples, their surface pores and shape distribution were studied by using SEM. Then, types and distribution of surface functional groups were explored by FTIR spectrometer. When R₀ of HP-SH coal sample increased from 0.70% to 2.88%, surface pores tended to be rough and more complicated with a porosity ranging between 65.29%-77.07%. Relative content of oxygen functional groups gradually increased with an relative ratio of -O- between 10.1% -19.25%, that of -OH between 7.16%-41.79% and -COOH between 52.01%-51.96%. Aromaticity and polymerization degree also gradually increased with aromaticity ranging between 1.09-1.63 and the other 0.29-1.58, and aromatic structure parameters of coal samples kept a linear relation with surface porosity. The results show that functional groups on micro-surface of coal samples will be similar as coalification degree becomes greater. The more complex functional group structure is, the more complicated that of micro-surface pore will be, thus providing an environment for micro-surface to reserve gas.

Antensive form game theory based multi-ship collision avoidance scheme

OUYANG Xudong, ZHI Yunxiang, WANG Tengfei, WU Bing, WANG Yang

2020, 30(1): 128-135. doi:10.16265/j.cnki.issn1003-3033.2020.01.020

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This paper is aimed at revealing the motives and preferences of ship operators in collision avoidance decision-making for ship collision avoidance (SCA) research, and more accurately reflecting the changing trend of each ship's motion in MSCA scenarios. The game model was introduced into the existing MSCA analysis, and a method was proposed to transform the MSCA problem into a non-zero-sum dynamic game problem with complete information between related ships. Firstly, the collision risk of the encounter situations was estimated by using parameters such as DCPA and TCPA, and the SCA priority matrix of all involved ships was established. Secondly, by considering the principles of the Conventional International Regulations for Preventing Collisions at Sea (COLREGS) and choosing ship maneuverability and economy preference as SCA decision making features, the extensive form game tree was established for each ship. Finally, the backward induction was used to obtain the subgame Nash equilibrium. The simulation results show that the presented game theory-based MSCA model provides more beneficial strategy than the conventional MSCA models in terms of solving the collision-prone situation.

Research on photoelectric surveillance warning system and design scheme for airport surface

XIA Zhenghong, ZHANG Qiang, ZHU Xinping

2020, 30(1): 136-141. doi:10.16265/j.cnki.issn1003-3033.2020.01.021

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In order to reduce unsafe incidents and incidents of airport surface, a photoelectric surveillance warning method and system design scheme based on infrared and visible light sensors were proposed. Firstly, a panoramic photoelectric situation was formed through four steps, fusing, splicing, correcting and reconstructing infrared and visible images. Then, classification recognition and continuous tracking were conducted on moving objects of airport surface and classified warning was given for potential conflicts which were predicted through analyzing moving objects' behaviors and intentions. Finally, this solution was applied to one airport in southwest of China. The results show that integrated solution of photoelectric surveillance warning system can realize panoramic monitoring of large-scale airport scenes and achieve target recognition and tracking in complex weathers as well as intelligent conflict prediction and early warning. It is characterized by advantages of all-time, all-weather visual display, early warning and low cost, etc.

Study on ground impact risk of UAV based on flight environment

HAN Peng, ZHAO Yifei

2020, 30(1): 142-147. doi:10.16265/j.cnki.issn1003-3033.2020.01.022

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In order to study impacts of different flight environments on UAV ground impact risks, it is necessary to analyze boundary conditions of UAV ground impact accidents under different flight operation conditions considering mission conditions and environment scenarios of UAV have a great impact on flight safety. Firstly, flight environment factors affecting UAV safety were analyzed, in which ground population density and shelter protection capability of various mission scenarios were considered and environment influencing factors were introduced to analyze meteorological, geographical and communication elements. Then, an evaluation model of UAV ground impact accidents was established with number of casualties per flight hour as evaluating indicators. Finally, risk parameters of various UAVs in different mission and environmental scenarios were calculated and compared. The results show that meteorological, terrain and communication factors of flight environment have a great impact on UAV ground impact risk. With the deterioration of environment, number of casualties per flight hour of UAV operation would change significantly with an increase rate from 10^-8 to 10^-5.

Microscopic simulation and accident probability of traffic flow in ice and snow environment

ZHANG Shan, PANG Mingbao, REN Boning

2020, 30(1): 148-154. doi:10.16265/j.cnki.issn1003-3033.2020.01.023

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In order to provide more scientific decision support for traffic control so as to improve driving safety under ice and snow conditions, vehicle force and driving behaviors were analyzed, and possible rear-end collision and side-slip accidents were discussed based on drivers' characteristics. Then, a CAM of two-lane one-way possible traffic accidents under ice and snow conditions was established. Finally, through traffic simulation, this model was validated, and flow-density characteristics and accident probability with control measures were analyzed. The results indicate that different measures should be taken to reduce accident probability according to specific ice and snow conditions and road geometry. It can be reduced by 41.02% through using deicing salt and setting speed limit on horizontal road covered with smooth ice film, and more than 34.20% if different speed limits were set on horizontal road in other ice and snow environment. It can also be reduced effectively by using deicing salt combined with classified speed-limiting measures on longitudinal slope road. And anti-skid chains or winter tires should be installed for vehicles on longitudinal slope road under smooth ice film so as to improve driving safety.

Subway construction accident causation network modeling and analysis

GUO Wenya, ZHOU Zhipeng

2020, 30(1): 155-161. doi:10.16265/j.cnki.issn1003-3033.2020.01.024

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In order to reveal evolution law between accidents and their causation factors, a double-layer SCACN model combining causation layer and accident layer were built based on real cases of subway construction, and network topological structure and internal mechanism were analyzed. According to calculation, cumulative degree distribution of its sub-networks all followed a power law with smaller shortest path length and higher clustering coefficient, and they presented features of scale-free and small-world networks. Also, SCACN showed robustness to random attacks but vulnerability to specific attacks. The results show that inadequate safety management, lack of safety awareness, and mechanical failure are initial causation factors that lead to a large number of accidents. Eliminating key nodes with large degree will reduce subsequent accidents to the maximum extent and improve safety management of subway engineering construction.

Tunnel emergency simulation and deduction system based on MR and microservice

YU Gang, SHI Lihua

2020, 30(1): 162-167. doi:10.16265/j.cnki.issn1003-3033.2020.01.025

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In order to improve emergency personnel's ability to deal with accidents in tunnels, a novel tunnel emergency simulation and deduction system (TESDS) based on MR and microservice is proposed. With MR and BIM as carriers, a realistic and interactive virtual environment was constructed. And microservice architecture and lightweight communication mechanism were adopted to accomplish such functions as dynamic scene loading, deduction execution, judgment, and decision analysis. Then, the system was applied in emergency management of Hongmei South Road Cross River Tunnel in Shanghai. It shows that emergency personnel's grasp of related knowledge has improved significantly in half a year, meeting new requirements in emergency management.

Multi-criteria group decision-making for emergency logistics route by heterogeneous decision makers

ZHANG Youyang, ZHU Changfeng, HAN Fu

2020, 30(1): 168-173. doi:10.16265/j.cnki.issn1003-3033.2020.01.026

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In order to improve emergency rescue efficiency and ensure the emergency supplies being delivered timely, several evaluation indexes were selected to construct the intuitionistic fuzzy evaluation matrix to simplify the complexity of emergency logistics path optimization. In addition, the MPT was applied to divide decision makers according to different decision preferences into three categories: risk-taking, intermediate and conservative. An emergency logistics path decision method under heterogeneous decision makers division was established. Then the results of risk-taking, intermediate and conservative decision-making were obtained and contrasted by case analysis, and on this basis, the sensitivity of several key parameters was analyzed. The results show that compared with existing methods, this proposed method takes the rationality of heterogeneous decision makers into consideration and makes the decision results more conform to reality, and that the decision outcomes are affected both by rationality and decision preference of decision makers.

Impact of cyclist's torso posture on head injury

ZHOU Hua, TANG Mei, LIU Feng, ZHANG Aihong, LI Pingfei, TAN Zhengping

2020, 30(1): 174-179. doi:10.16265/j.cnki.issn1003-3033.2020.01.027

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In order to study impacts of torso yaw angle, torso anterior angle and participant's collision speed on cyclist's HIC in frontal collision accidents between electric bicycle and SUV, a simulation experiment was designed based on multi-rigid body model of SUV and electric bicycle verified by MADYMO software. The results show that the HIC value will gradually decrease as cyclist's torso yaw angle increases, and also do so as torso anterior angle increases when electric bicycle's speed doesn't exceed 15 km/h or SUV exceeds 50 km/h. Otherwise, it will increase first and then decrease with the increase of the torso anterior angle when the former exceeds 15 km/h or the latter no more than 50 km/h. Cyclist's head injury can be reduced by increasing torso yaw angle and anterior angle simultaneously in advance.

Dynamic comfort evaluation for operators in high-altitude mines

NIE Xingxin, FENG Shanshan, ZHANG Shudu, GAN Quan

2020, 30(1): 180-186. doi:10.16265/j.cnki.issn1003-3033.2020.01.028

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In order to help address problems of poor ventilation and waste of ventilation energy consumption in high-altitude mines, dynamic thermal comfort evaluation for operators was conducted through a modified PMV model. Firstly hourly thermal comfort on mine surface was calculated according to meteorological parameter information of typical working days, and a control chart of it was generated. Then, an underground PMV model was established to obtain control curves of natural thermal environment underground, which reflected changes of operators' thermal comfort in real time. The results show that comfort of surface environment is slightly cooler during 12:00-19:00, cooler during 7:00-12:00 and 19:00-3:00, and cold during 3:00-7:00. The PMV model tested and verified by experiments is suitable for high-altitude and low-pressure environment. After optimization, underground thermal comfort at 0:00-12:00 and 18:00-0:00 is neutral, and it is slightly warmer at 12:00-18:00. Optimized underground thermal comfort index is closer to optimal value of human thermal comfort.

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