China Safety Science Journal

Vulnerability assessment of rainfall and waterlogging in subway stations based on projection pursuit model

WANG Junwu, WU Han, YANG Tingyou

2019, 29(9): 1-7. doi:10.16265/j.cnki.issn1003-3033.2019.09.001

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In order to scientifically evaluate vulnerability of heavy rainfall and waterlogging in subway stations, enhance prevention and emergency response ability as well as reduce injuries and loss of life and property, firstly, vulnerability factors were comprehensively identified and furthermore an evaluation index system was constructed based on PSR model. Then, a model of vulnerability assessment was established combining methods of projection pursuit, particle swarm optimization and others. Finally, all station projects of Chengdu subway line 11 were selected for empirical analysis. The results show that poor surrounding environment, height of water retaining walls and disaster relief supplies storage have obvious impacts on vulnerability and should be paid close attention to, and adaptability is a key element of vulnerability. Empirical evaluation results are basically consistent with the disaster situation of flood season in 2018.

Research on generation mechanism of safety culture

WANG Bing, WU Chao

2019, 29(9): 8-12. doi:10.16265/j.cnki.issn1003-3033.2019.09.002

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In order to clarify the generation law of safety culture, and further enrich and improve the theories of safety culturology, this research is carried out to systematically study the generation mechanism of safety culture by using the methods of theoretical speculation and literature analysis from a comprehensive perspective of "macro-middle-micro sense". Firstly, the definition of safety culture generation was put forward, and six factors of it, such as human needs of safety, safety threats and responders, were extracted out. Then, five approaches like the united type, practical type and rational type and two kinds of power-spontaneous type and operational type were proposed. Finally, four expression forms, including the formal form, experience form and theoretical form were analyzed. The results show that the core mechanism of safety culture generation can be summed up as the "6-5-2-4" generation theory of safety culture, which includes generation factors, approaches, power and expression forms.

Development of questionnaire on miners' mind wandering

LI Naiwen, XU Chang

2019, 29(9): 13-19. doi:10.16265/j.cnki.issn1003-3033.2019.09.003

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In order to develop a questionnaire on miners' characteristic mind wandering, based on the qualitative research on it, firstly, an initial questionnaire of 89 initial items concerning mind wandering inducement, content and result was prepared. Then, taking 551 miners as research objects, project analysis and confirmatory factor analysis were conducted for initial questionnaires, and a formal questionnaire of 54 items was developed from 9 dimensions, including physical and mental state, personal traits, spontaneous thinking, external factors, irrelevant assignment tasks, assignment task results, assignment task processes, negative mind wandering and positive mind wandering. The results show that the proposed questionnaire has high reliability and validity as it can measure miners‘ mind wandering effectively and provide scientific basis for safety managers of coal mining enterprises to manage and control miners' mind wandering effectively.

Classification and responsibility identification of individual unsafe behaviors based on behavior flow

HUANG Lang, WU Chao, MA Jian

2019, 29(9): 20-26. doi:10.16265/j.cnki.issn1003-3033.2019.09.004

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In order to perfect the theoretical system of behavior-based safety management and safety information cognition, the classification and responsibility identification procedures of unsafe behaviors were developed. Firstly, the concept of behavior flow was put forward and its connation was analyzed based on the concepts of information flow and cognition flow. Secondly, the behavior modules and deviation model related to different behavior patterns were analyzed. Lastly, the responsibility identification procedures of unsafe behaviors were constructed based on behavior flow and behaviors pattern. The results show that the individual behavior flow consists of safety information acquisition, analysis and utilization, that the classification framework including ignoring, time deviation, sequence deviation, target deviation, and action deviation, that the responsibility identification procedures of individual unsafe behaviors can be summarized to five categories, and that the proposed classification and responsibility identification procedures are feasible and effective.

Study on human error in AIDC transfer based on STPA and fuzzy BN

WANG Jiening, LI Baoshen, JI Shanshan

2019, 29(9): 27-35. doi:10.16265/j.cnki.issn1003-3033.2019.09.005

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In order to assess potential human risk in the transfer of air traffic control due to incomplete functions of air traffic control automation system, firstly, key human errors in AIDC transfer were identified through developing a control feedback structure diagram with STPA method. Then a BN-based human error analysis model was constructed in combination with HERA-JANUS, and prior probability of each node was quantized building on expert experience and fuzzy set theory. Finally, through visually diagnosing fuzzy BN with training data of GeNIe software, occurrence probability of target events was finally acquired and key human errors were concluded. The results show that fuzzy BN driven by STPA method can comprehensively identify key human error causes in AIDC transfer, among which dearth of system warnings in the event of transfer failure is a key hazard source of human errors during transfer process. And when target event occurs, four kinds of human error behaviors have higher probability to occur, including “controllers' distraction”, “forgotten monitoring”, “low concentration” and “diminished alertness”, which are four fundamental causes that result in a smaller and dangerous interval during the transfer of AIDC.

Simulation study on influences of construction workers' bounded rational cognition on unsafe behaviors

YE Gui, YUE Hongzhe, YANG Jingjing, FENG Xinyi, WANG Yuhe

2019, 29(9): 36-42. doi:10.16265/j.cnki.issn1003-3033.2019.09.006

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In order to analyze cognitive process of construction workers with bounded rationality, influences on their unsafe behaviors of three cognitive factors, namely risk perception experience, risk degree and action execution level of construction workers were explored in both situations of complete information and incomplete information. A four-stage cognitive model was constructed then and Matlab simulations were conducted with construction workers of an engineering project as empirical objects and initial parameters being set. The results show that construction worker's cognition is updated more frequently and and there is a smaller proportion of unsafe behaviors and hazardous events in case of complete information compared with that of incomplete information. Experience can help workers recognize risks to a certain extent, but excessive reliance on risk perception experience can lead to unsafe behaviors. The more rational workers are and they stronger executive power they have, the fewer unsafe behaviors there will be.

Study on natural gas leakage and diffusion in utility tunnels and optimization of monitoring methods

HE Leping, TANG Shuang, HU Qijun, CAI Qijie, SHI Rendan

2019, 29(9): 43-50. doi:10.16265/j.cnki.issn1003-3033.2019.09.007

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In order to determine locations of CH₄ sensors in utility tunnels so as to improve safety of gas transportation in natural gas compartments, a three-dimensional CFD model was built to study CH₄ leakage and diffusion under factors of pipeline pressure grade, leakage aperture, leakage angle, ventilation speed, ventilation temperature and section type. The results show that CH₄ diffusion rises to utility top and then migrates down to compartment bottom along with increase of longitudinal diffusion length under comprehensive factors. CH₄ sensors should be placed on walls that are much closer to pipes if the pipe is not in the center of compartment or installed on either side of the wall when it is at the center. And sensors should be 0.6-1.6 m high above gas release source.

Research on cloud model for safety evaluation of rail transit vehicle system

WANG Kang, DONG Sihui

2019, 29(9): 51-56. doi:10.16265/j.cnki.issn1003-3033.2019.09.008

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In order to evaluate safety status of rail transit vehicle systems more accurately and solve ambiguity of single method evaluation, an evaluation method based on SD and cloud model is proposed. Firstly, a safety evaluation index system was put forward on the basis of questionnaire survey and current relevant standards. Secondly, principal component analysis and SD model were used to analyze weights of each index. Then, a cloud model for safety evaluation of rail transit vehicle system was established to assess safety status of the system and its subsystems. Finally, model verification was conducted with Dalian Metro Line 1 as an example. The results show that drive system, vehicle safety equipment and vehicle monitoring system constitute important subsystems of rail transit vehicle system. Safety evaluation cloud model can intuitively assess system safety and facilitate its safety management.

Application of RAGA-PPC cloud model in slope stability evaluation

WU Menglong, YE Yicheng, HU Nanyan, YAO Nan, JIANG Huimin, LI Wen

2019, 29(9): 57-63. doi:10.16265/j.cnki.issn1003-3033.2019.09.009

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In order to accurately evaluate slope stability of open pits and prevent slope accidents, firstly, six indexes, including cohesion, slope angle, slope height, pore water pressure ratio and natural bulk density, were selected to establish a slope stability evaluation index system. Secondly, based on 20 sets of samples, PPC method was adopted to project multidimensional data on one-dimensional plane, and weight values of each index were calculated with RAGA optimized projection indexes. Then, membership degree of each stability level were obtained by using forward cloud generator, on the basis of which weighted membership degree of slope stability levels was calculated. Finally, a RAGA-PPC evaluation cloud model combining qualitative and quantitative analysis was constructed and verified through 5 groups of samples. The results show that the most important factor that affects slope stability is slope height. RAGA-PPC cloud model's accuracy rate for evaluating 20 sets of sample data is 95.0% and 100% for 5 sets of sample data.

Mesoscopic traffic flow simulation based on heterogeneous driving behaviors and collision

SHI Xueying, SUN Zhicheng, ZHU Tong

2019, 29(9): 64-69. doi:10.16265/j.cnki.issn1003-3033.2019.09.010

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To study heterogeneity of driving behaviors and its influence on traffic flow characteristics, firstly a questionnaire-based survey was conducted to investigate heterogeneous driving behaviors under influences of surrounding vehicles' speed, traffic flow density, number of stops, collision accidents and other factors. Then according to survey results, a meso-traffic flow model based on multi-agent system was established using NetLogo, and heterogeneous driving behaviors and collision factors were deployed to simulate evolution process of traffic flows. The results show that drivers would adjust driving speed to different degrees influenced by surrounding vehicles' speed, and their average driving speed is related to their own characteristics. Behaviors of changing lanes are determined by traffic flow density and number of stops, and heterogeneity of this behavior makes distribution of vehicles in each lane change in a tidal manner and therefore affects traffic flow stability. It is also found that collision accidents can reduce driving speed and cause traffic bottlenecks.

Study on longitudinal decay of flue gas temperature in underwater V-shaped slope tunnels

JIANG Xuepeng, XIE Zhiyun, YU Siwei, LIAO Xiangjuan

2019, 29(9): 70-76. doi:10.16265/j.cnki.issn1003-3033.2019.09.011

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In order to study temperature distribution of fire smoke in underwater V-shaped slop tunnels, firstly, smoke flow and temperature distribution characteristics in horizontal tunnels, single-slope tunnels and V-slope tunnels were compared and analyzed through theoretical analysis and numerical simulation method. Then the influence of tunnel slope shapes on flue gas movement and temperature distribution of different slope tunnels were explored. Finally, an attenuation prediction model of flue gas temperature under roof of V-slope tunnels within 1 to 8 degrees was established. The results show that temperature distribution along V-shaped slop tunnel obeys exponential function distribution, which is slower than that upstream of single-slope tunnels, faster than that downstream of single-slope tunnels, and slightly faster than that of horizontal tunnels. At the same time, the dimensionless temperature rise parameters of prediction model have an exponential relationship of 0.6 with power of fire source and a certain non-linear relationship with tunnel slops.

Low-temperature oxidation characteristics of compacted broken coal and macroscopic cause analysis

CHU Tingxiang, HAN Xuefeng, YU Minggao

2019, 29(9): 77-83. doi:10.16265/j.cnki.issn1003-3033.2019.09.012

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In order to identify the effects of stress loading on the oxidation process of broken coal, firstly, using self-designed experimental devices, low-temperature oxidation experiments of compacted broken coal were conducted under different stress loading. Secondly, the oxygen consumption rate, CO and C₂H₄gas generation characteristics were analyzed based on the test data. Finally, variation causes of coal oxidation under different stress loading states were analyzed. Results show that,while at the same temperature, the oxygen consumption intensity and generation amount of CO and C₂H₄will increase with the increase of axial loading strength, and the C₂H₄ occurrence temperature was advanced, with the increase of axial pressure, the oxidation activity of coal samples will be enhanced which contributes to the occurrence of low temperature oxidation and spontaneous combustion of coal, it was also found that the increases of fractal dimension, the specific surface area and the thermal conductivity coefficient are the causes for oxidation behavior variance of compacted broken coal.

Experimental study on effects of plus water content on low-temperature oxidation of coal

LI Wanhong, CHU Tingxiang, LIU Wende, ZHOU Liping, ZENG Yanming

2019, 29(9): 84-89. doi:10.16265/j.cnki.issn1003-3033.2019.09.013

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In order to determine inhibition effects of plus water content on coal's self combustion, low temperature oxidation experiment and thermal analysis technique were adopted to test indicators like carbon monoxide occurrence, ethylene production, oxygen consumption rate, crossing point and endothermal peak temperature, and low-temperature oxidation characteristics of coal samples with different water content were analyzed. The experimental results show that oxygen consumption and oxidation gas production are larger compared with natural air-dried coal samples when content is in the range of(0, 9%], and increase of water content speeds up spontaneous combustion of coal.Oxygen consumption and oxidation gas production are smaller in the range of(9, 25%], and spontaneous combustion of coal will be inhibited by increase of water content. Crossing point and endothermic peak temperature reach minimum with 9% of water content within all tested coal samples. Therefore, when adopting hydraulic fire-fighting measures, attention should be paid to humidifying effects of coal to ensure that residual coal is with corresponding water content.

Study on cooling effects of insulation layers of life rescue capsule

ZHU Jingcheng, ZHANG Jiaqi

2019, 29(9): 90-95. doi:10.16265/j.cnki.issn1003-3033.2019.09.014

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In order to improve thermal insulation performance of heat-protective layers of fire rescue capsule structure, a high temperature test platform for insulation performance was built based on multi-layer gas insulated construction with multi-layer serpentine pipelines and aluminum silicate fiberboards to test thermal insulation effect of each layer before and after adding aluminum foil in high temperature environment. Then, low temperature carbon dioxide gas and normal temperature air were injected into thermal insulation pipelines at different inner temperature. At last, influences of the two gases on cooling effects of each layer were explored. The results show that adding aluminum foil in insulation structure can improve thermal insulation efficiency, and it will be most effective when heating temperature reaches 600 ℃ with an increase of 39.3% for insulation efficiency which will gradually decrease as temperature continues to rise. Cooling effects of gases depend on temperature difference between the gas and insulation layers, the greater temperature difference is, the more obvious cooling effects are, and low temperature gas works better than normal temperature gas.

Effects of obstacles on gas explosion shock wave propagation

XU Ameng, CHEN Xuexi, JIA Jinzhang

2019, 29(9): 96-101. doi:10.16265/j.cnki.issn1003-3033.2019.09.015

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In order to study propagation characteristics of gas explosion shock waves and flame waves in pipelines with differently-shaped obstacles, Fluent software was used to simulate changes of overpressure and temperature during gas explosion, and effects of circular, square and rectangular obstacles on gas explosion shock waves and flame waves were systematically studied. The results show that peak pressure of gas explosion can reach 0.84 MPa when a square obstacle with a side length of 0.13 m exists in pipelines and explosion-proof facilities should be strengthened especially where there are square obstacles in actual roadways. For all obstacles of various shapes, increase of their sizes will lead to increase of peak explosion overpressure. For circular obstacles, peak temperature increases first and then decreases and its change range is small when blocking rate changes from less than 50% to more than 50%. Therefore, it can be inferred that peak temperature will change in different ways with a blocking rate of 50% as the boundary. As for square and circular obstacles, peak temperature will increase with an increase of blocking rate. It is also found that explosive flame waves will flow around different obstacles, indicating that obstacles will accelerate propagation of flame waves.

Research on minimum explosible concentration of dust based on method of combustion duration

TAN Xin, ZHAO Peng, WU Dejian, HUANG Weixing, YUAN Jingjie

2019, 29(9): 102-106. doi:10.16265/j.cnki.issn1003-3033.2019.09.016

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To improve the reliability of MEC tests, a method of measuring MEC by combustion duration was proposed. Through theoretical analysis of the relationship between the flame propagation rate and dust concentration, systematical experiments were performed in the 20 L sphere vessel to investigate the basic variation behavior of combustion duration under different ignition energy, particle size and dust concentration. The feasibility of the combustion duration method was verified by MEC experimental results. The results show that the combustion duration time essentially characterizes explosive dynamics features and the concentration at the maximum of combustion duration time is MEC, and that the results of MEC determined by this proposed combustion duration method are in good agrement with those obtained by current pressure-benchmarked test method, but the proposed method is more stable and accurate.

Influence of cavity length on gas explosion suppression

ZHOU Hui, MU Chaomin, LIU Wei, HUANG Haijian

2019, 29(9): 107-112. doi:10.16265/j.cnki.issn1003-3033.2019.09.017

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In order to explore the relationship between length of cavity structure attached to straight pipes and effectiveness of gas explosion suppression, rectangular cavities with a cross-section at 500 mm×200 mm and lengths at 300, 500 and 800 mm separately were designed, and then suppression experiments were carried out by applying cavities of different lengths in a self-built 36 m-long gas explosive test system. The results show that cavities of different lengths can suppress explosion flame front to a certain extent. Flame elimination effect of a single cavity is linearly related to its length, and the highest flame suppression rate can reach 76.91% within experimental range. Overpressure inhibition rate is logarithmic to its length, and there exists a critical length of cavity for suppressing overpressure. When it is 300 mm long, overpressure peak will rise by 9.5% while its suppression rate will improve from 17.59% to 28.53% as the length increases from 500 mm to 800 mm.

Identification method of mine water inrush source based on IWOA-HKELM

SHAO Liangshan, ZHAN Xiaofan

2019, 29(9): 113-118. doi:10.16265/j.cnki.issn1003-3033.2019.09.018

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In order to improve accuracy in identifying mine water inrush source, an IWOA-HKELM water source identification model is proposed. Firstly, HKELM, featuring better learning ability and generalization performance, was constructed on combined basis of Gaussian kernel function and polynomial kernel function. Secondly, IWOA algorithm was proposed considering that WOA was easy to fall into local optimization. Then, three strategies were introduced to reduce probability of premature convergence and obtain better results, including tent mapping, improvement of non-linear factor and setting of reverse elite learning threshold. Finally, water inrush source data of Xinzhuangzi Mine, being taken as simulation data, was put in IWOA-HKELM model for result prediction after dimension reduction. The results show that optimization of HKELM parameters through IWOA can improve the algorithm's overall prediction performance. Prediction results of IWOA-HKELM are completely consistent with actual situation. Compared with other models, the proposed model obviously excels in terms of average classification accuracy with its average mean square error and standard deviation of classification accuracy being significantly reduced.

Research on runway incursion conflict detection and alarm based on ADS-B

SHEN Xiaoyun, ZHANG Xiaoyan, ZHANG Siyuan

2019, 29(9): 119-124. doi:10.16265/j.cnki.issn1003-3033.2019.09.019

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In order to prevent accidents caused by civil aviation runway incursion, ADS-B technology was used to obtain real-time position of moving targets through information reported by ADS-B, and then it was determined whether there was a runway incursion according to positional relationship between moving targets and runway protection areas before an incursion alarm was generated. Secondly, runway conflict was identified and alarm was generated according to relative motion state, spatial distance and encounter time between moving targets. Finally, conflict scenarios and a two level alarm mechanism were constructed based on Geographic Information Systems to study runway incursion conflict detection and alarm system. The results show that when there are two moving targets in runway protection zones, the system will generate a runway incursion alarm. When moving targets are close to each other, spatial distance is smaller than minimum safety interval, encounter time is less than 30s, and the system then generates a conflict alarm.

FMEA approach for risk evaluation based on consensus model and IN-TODIM

WANG Rui, ZHU Jianghong, LI Yanlai

2019, 29(9): 125-131. doi:10.16265/j.cnki.issn1003-3033.2019.09.020

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In order to make traditional FMEA approach more scientific and accurate, a novel FMEA approach for risk evaluation under interval neutrosophic background was proposed, which considers both consensus level and risk preference of decision makers. Firstly, interval neutrosophic numbers were introduced to represent decision makers' evaluation on failure modes and risk factor weights, and a new consensus model was developed to accurately identify and revise non-consensus evaluation information. Secondly, weights of risk factors were determined according to collective evaluation matrix of consensus risk factors combined with evaluation information of risk factor weights and interval neutrosophic entropy measures. Finally, IN-TODIM method was constructed considering irrational psychological behaviors of decision makers to obtain risk ranking of failure modes, and it was also applied to evaluate risks of a steel smelter. The results show that the proposed FMEA approach can iteratively improve non-consensus evaluations that deviate from group opinions and thus obtain more accurate evaluation results.

Coupling risk analysis of road dangerous goods transportation system based on N-K model

YANG Ting, SHUAI Bin, HUANG Wencheng

2019, 29(9): 132-137. doi:10.16265/j.cnki.issn1003-3033.2019.09.021

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In order to identify risk factors in road transportation system of dangerous goods and prevent transportation accidents from the source, the N-K model was used to analyze the system risk coupling. Firstly, risk factors were divided into five categories: human, machine, material, environment and management. Then according to the number of risk factors involved in the coupling, single, double, triple, quadruple and five factors coupling risks were divided, and the N-K model was used to calculate the coupling risk values of various couplings. Finally, taking 220 road dangerous goods transportation accidents in China in the first half year of 2017 as examples, the system coupling risk was calculated. The results show that the more risk factors involved in coupling, the greater the coupling risk value will be, that the risk of coupling between human and environment is the greatest and that between material and management is the smallest, and that coupling risk between subject and objective is relatively large while the risk of multiple subjective factors coupling with each other is smaller.

Structural plane characteristics and stability of broken surrounding rocks

ZHAO Kang, WANG Qing, WANG Junqiang, SUO Tianyuan, HAO Jiaolong, LIU Xiaosheng

2019, 29(9): 138-143. doi:10.16265/j.cnki.issn1003-3033.2019.09.022

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In order to evaluate the stability of extremely fractured surrounding rocks in a gold mine, micro-fracture structural planes of the IV and V grade of the surrounding rocks in the mine were measured and analyzed in three production sections of +260, +295 and +330 m. The influences of joint spacing, occurrence, undulating shape, roughness, openness and seepage on surrounding rock stability were analyzed by scanline method. The distribution characteristics of dominant structural planes occurrence were discussed by using pole plot and rose plot. The results show that the surrounding rock joints are well developed and closely distributed, and the average spacing is less than 1m and is mainly concentrated in 0.2-0.6 m. The surrounding rocks are broken and extremely broken rock mass with poor stability. The dominant occurrence has obvious concentration in the middle of +260, +295 and +330 m. The dip is mainly concentrated at 324-360 ° and 0-35 °, and the dip direction is mainly concentrated at 70-79 °. The undulating state of the structural plane is mostly straight, which has a great influence on the stability of the structural plane. The structural surfaces are tightly combined with less filler, which has less influence on the structural surface stability.

Reconstruction of coal pore network based on improved watershed algorithm and seepage simulation

WU Xin, PENG Yawen, YAN Qiao, ZHAO Hongxia, WANG Xuemei

2019, 29(9): 144-149. doi:10.16265/j.cnki.issn1003-3033.2019.09.023

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In order to construct the digital pore network structure of coal to simulate the microscopic seepage process of gas in coal pores, the pore-reconstruction study of coal rock based on the morphological improvement of watershed algorithm was carried out. Firstly, a method based on improved watershed algorithm to identify coal matrix particle distribution parameters and pore network was proposed, and the noise influence was reduced by median filtering and mathematical morphology transformation to avoid the phenomenon of "over-segmentation". Then, taking 5-10 mesh, 10-40 mesh and 40-80 mesh size coal as examples, the particle distribution parameters were identified and the pore network structure of the coal was established. Finally, the seepage simulation test was carried out to verify pore network gas based on the LBM. The results show that the improved watershed algorithm reduces noise interference and the reconstructed coal pore structure has high complexity and connectivity, and that the seepage simulation of the pore structure by LBM algorithm can show local details such as gas seepage velocity and direction.

Research and application of grading dust suppression system on comprehensive heading faces

HUANG Yisheng, HU Shengyong, SHAO He, LIAO Qi, GAO Yang, HU Fei

2019, 29(9): 150-154. doi:10.16265/j.cnki.issn1003-3033.2019.09.024

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In order to solve shortcomings of dust removal technology in coal mining production process and reduce threats of excessive dust on workers' occupational health, firstly, analysis was made on current status of underground dust removal, through which it was found that the main reasons for current low dust removal efficiency are nozzles' tendency to be blocked, incomplete dust source coverage, effects of head wind flow on water mist and poor insulation effects of dust curtains. Secondly, based on dust generation characteristics of different areas and dust migration law, a regional grading dedusting system was proposed which consisted of a ring wrapped dust suppressor, an air curtain dust blasting knife and a double atomization device that respectively controlled dust in the front, middle and back regions of a comprehensive face. Finally, system device was applied on comprehensive face of 26 belt lane of Zhangcun Coal Mine to test dust removal effects. The results show that total dust and respirable dust suppression efficiency in working areas both reaches up to 95%, which is about 40% higher than that of current dust removal measures, basically making dust-free working areas possible.

Research on polycentric synergetic governance model for special equipment safety

HAO Suli

2019, 29(9): 155-160. doi:10.16265/j.cnki.issn1003-3033.2019.09.025

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In order to improve the safety supervision efficiency of special equipment and realize the transformation from "one part supervision" to "multi-center governance", theories of multi-centered governance, synergetics and entropy were applied to establish the multi-center governance system framework. The synergistic elements of governance, market and society were analyzed and the multi-centered collaborative governance mode of special equipment was established. Finally the synergy degree of each governance subject was given. The results show that the overall public participation degree is the largest (0.887), and the government's external synergy is the largest(1.0) but its overall coordination is the smallest. It indicates that under the current governance system, the government is still the key to safety management of special equipment, and it is necessary to strengthen the coordination of internal business segments. Enterprises should actively cooperate with other entities through market mechanisms, and inspection agencies must accelerate the process of marketization. This will improve the coordination of the entire governance system.

Comprehensive analysis method of multi-factor risks for highway traffic accidents in mountain areas: taking rain and fog weather for example

WEN Huiying, XUE Gang

2019, 29(9): 161-166. doi:10.16265/j.cnki.issn1003-3033.2019.09.026

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In order to improve the analytic theory and method of highway traffic accidents and risks under the influence of multiple factors, a comprehensive analytic model of multi-factor risks of traffic accidents in mountain area was proposed based on the joint return period of vulnerability surface and risk factors, and the typical rain and fog weather in mountainous highway traffic of Yunnan province was selected for case study. Firstly, a vulnerability surface model was established to represent the relationship between the strength of risk factors and the losses. Secondly, a copula-based risk factor analytic model was established. Finally, the risk curves of traffic participants' loss of life under the combined influence of multiple factors of rain and fog in four case study sections were obtained. The results show that the risk of highway traffic in mountainous area increases sharply under the influence of multi-hazard risk, and that the comprehensive analysis method proposed can quantify the absolute value of risks.

Safety early warning system for live working considering body signs

LI Wen, GU Su, MAO Dun, PAN Junwen, WANG Zhigang, MEI Wenjian

2019, 29(9): 167-172. doi:10.16265/j.cnki.issn1003-3033.2019.09.027

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In order to avoid the accidents of working personnel caused by thermal stress in enclosed structure of shielding suit for live operation, a safety early warning system based on body signs was developed based on the thermal stress theory. Firstly, the state parameters of human body were analyzed and set as the threshold of the early warning system. Secondly, the safety warning method was proposed and the design idea was introduced from five module including power supply, microprocessor, Wireless Fidelity(WiFi) communication, data acquisition and alarm. Finally, the WiFi communication function test, the heart rate detecting function test and the high-voltage electric field experiment were carried out by using the sample machine. The results show that the proposed system's endurance capacity is greater than 8 h, that WiFi communication distance is greater than 15 m, that the heart rate error is less than 3%, and that it can work normally under 300 kV high pressure environment.

Location of maritime emergency supplies repertories considering risk uncertainty

ZHANG Lingye, LYU Jing

2019, 29(9): 173-180. doi:10.16265/j.cnki.issn1003-3033.2019.09.028

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In order to improve the rescue service capability of maritime emergency system, site selection of maritime emergency material reserve was studied. Firstly, according to the characteristics of maritime emergency response, the concept of emergency response satisfaction was introduced from the perspectives of timeliness, effectiveness and the difference in the demand for emergency response services among accidents with different risk levels. Based on this, a site selection model of marine emergency material reserve was constructed to realize the maximization of emergency efficiency. Then the uncertainty of the overall distribution of risk value of maritime accidents was analyzed by discrete simulation scenarios, and the robust optimization model of the location of storage pool was constructed by using robust theory. Finally, genetic algorithm was used to obtain the final location scheme. The results show that in discrete simulation scenarios with significant difference in risk distribution, the proposed robust optimization model are more stable than deterministic model and it can ensure the reliability of the location scheme.

An experimental study on evacuation characteristics and restrictive factors for passengers evacuating from a motorcoach

ZHANG Shuo, HUANG Rong, YU Qiang

2019, 29(9): 181-187. doi:10.16265/j.cnki.issn1003-3033.2019.09.029

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In order to promote the formulation and improvement of safety regulations of motorcoaches and improve its safety design level, an evacuation experiment with 45 passengers aged 20-68 was conducted in six scenarios. Firstly, evacuation movement data of passengers were collected with an on-vehicle video system and then macroscopic evacuation performances of motorcoaches in different scenarios were compared to obtain key factors that affect evacuation efficiency by using variance analysis. Finally, key movement parameters of passengers in aisles in front of stairs were collected, and velocity-density relationship was constructed. The results show that evacuation takes the longest time (i.e. 63 second) in a rear door opening scenario, and available exits, evacuation drill and door width have a significant influence on evacuation efficiency. Furthermore, average speeds of passengers on the front and rear stairs are (0.93±0.31)m/s and (0.90±0.31)m/s respectively. Velocity-density relationship curve is consistent with related researches in terms of values and trends.

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