China Safety Science Journal

Urban resilience evaluation system and optimization strategy from perspective of disaster prevention

XU Zhaofeng, TIAN Jiefang, ZHANG Jing

2019, 29(3): 1-7. doi:10.16265/j.cnki.issn1003-3033.2019.03.001

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In order to promote urban disaster resilience, urban resilience was studied from the perspective of disaster prevention. Firstly, urban resilience was analyzed from four aspects including infrastructure resilience, economic resilience, social resilience, organizational and institutional resilience, and the evaluation index system was constructed. Then the weight of each index was calculated by analytic hierarchy process method, and the comprehensive evaluation model of urban disaster resilience was estalished by cloud matter-element method. Finally, the validity of the model was verified by taking Tangshan City, Hebei Province as an example, and the optimization suggestions for the construction of resilient cities were proposed based on the evaluation results. The results show that infrastructure resilience and organizational and institutional resilience are main factors that should be considered in the evaluation of urban disaster resilience, and that the comprehensive disaster resilience level of Tangshan city is calculated as good by the model, which is consistent with the actual situation.

Study on relations between village road vehicles meeting characteristics and driver's psychological physiological state

QIAO Jian'gang , WU Yanxia , XU Jun

2019, 29(3): 8-13. doi:10.16265/j.cnki.issn1003-3033.2019.03.002

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For the sake of improving the safety of driving on village road, the paper was aimed at analyzing the relations between the running characteristics of the vehicle and the physiological state of the driver during the vehicles meeting process based on the theories of traffic engineering, psychology and human factor engineering. Data on the driver's psychological and physiological changes and the vehicle speed and other parameters were obtained through field testing. The speed change of the vehicle during the vehicles meeting and the driver's heart rate growth rate were analyzed. The relationship between the vehicle speed change and the heart rate growth rate during the meeting process on the straight line segment was studied. The relationships between the vehicle speed, the growth rate of driver's heart rate and the flat curve radius on the curved section were analyzed. The results show that the driver feels an obvious tension when the vehicles crossing each other, and the vehicle speed in the meeting duration undergoes an U-shaped change process, however the change in the corresponding heart rate growth rate undergoes a process opposite to the U-shaped change process, and that when the curve radius gets larger, the vehicles speed get higher when crossing each other, however the growth rate of driver's heart rate gets lower.

Fine modes of repeat speeding behaviors

FU Chuanyun, LI Yajie, HU Zhongyu

2019, 29(3): 14-20. doi:10.16265/j.cnki.issn1003-3033.2019.03.003

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In order to prevent speeding recidivists, the fine modes of repeat speeding behavior and their applicable conditions have been explored. According to the speeding records of motorized vehicles from 2015 to 2017 collected in Deyang City, the type of speeding vehicle were classified. After quantifying speeding gains violations, three fine modes were established, including low uniform fine, increasing block fine, and high uniform fine. Based on these fine modes, the cost-benefit theory was utilized to propose the calculation methods of social welfares generated by speeding. And then, the social welfares associated with three fine modes were compared respectively in two cases where both acceptable gain and illicit gain were fixed, and the acceptable gain was stochastic while the illicit gain was fixed. According to the aforementioned comparisons, the application condition for each fine mode was determined. In the end, a numerical example analysis was conducted. The results show that if the social loss caused by speeding is comparatively great, the increasing block fine mode outperforms the low uniform fine mode, but underperforms the high uniform fine mode; conversely, the opposite is true. The increasing block fine mode is the most compromised solution.

Study on injury to occupants in car left rear line of seats in offset collision

PENG Cong, ZHANG Daowen, YANG Ling, LIU Zhuoyi

2019, 29(3): 21-26. doi:10.16265/j.cnki.issn1003-3033.2019.03.004

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To identify the characteristics of the injury to left rear occupants in car frontal offset collision, simulation studies were conducted. The HyperMesh finite element software was used to build a basic model 1, including a finite element car, a deformable wall, and a dummy. A three-point seat belt was added to the basic model 1, and a model 2 was built. A side airbag was created to the model 2, and a model 3 was built. The Ls-Dyna software was used to solve the calculation, and the HyperGraph software was used to analyze the injury to the dummy under different overlapping rates in offset collisions. A comparison was made between the injuries to the dummy in the basic model 1, model 2 and model 3. The effectiveness of the different restraint systems in protecting the left rear dummy was analyzed. The results show that there isa negative correlation between the collision overlap rate and the acceleration peaks of the left rear occupant'shead and chest, that when the collision overlap rate changes within the test range, the peak fluctuation of the resultant force on the neck is small, that the use of seat belt can significantly reduce occupant damage, and that the side airbag is very effective in protecting the occupant's chest.

Study on safety of power Li-ion battery based on puncturing experiments

PENG Bo, LUO Qiongyao, ZHANG Yi, WANG Lifen, ZHAO Changzheng

2019, 29(3): 27-31. doi:10.16265/j.cnki.issn1003-3033.2019.03.005

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In order to study the safety performance of power Li-ion battery in puncturing, puncturing experiments of different depths and speeds were carried out on three kinds of common 18650-type Li-ion batteries (two kinds of them are positive cobalt acid lithium materials and the other ternary materials). During the puncturing process, surface temperature of the positive electrode of the battery was monitored to evaluate its risks for fire and explosion. The results show that the deeper the puncturing depth is, the higher the temperature-rise rate of Li-ion battery and fire risk will be, that when the puncturing depth is 100%, puncturing speed has little effect on the temperature rise of these two kinds of batteries using a cathode material, that the temperature-rise rates of the same kind of batteries are almost the same under different puncturing speeds, and that temperature of LiCoO₂ Li-ion battery rises faster and reaches higher than that of ternary materials Li-ion battery under the same puncturing speed.

Research on evacuation route from high-rise building under real effect of fire spread

ZHANG Mingkong, HU Xiaobing, WANG Jing'ai

2019, 29(3): 32-38. doi:10.16265/j.cnki.issn1003-3033.2019.03.006

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In order to provide the optimal evacuation path for people and improve the emergency response capability, CEPO method based on RSA is proposed in this paper. Fire Dynamics Simulator(FDS) was used to obtain fire spreading parameters and simulate the fire spreading process, then the CEPO based on the RSA was used to optimize the evacuation path with fire real-time spreading, and Dynamic Path Optimization(DPO) method was taken to verify the effectiveness of the CEPO method. By simulating the high-rise fire evacuation process, the results show that t he total evacuation time of the CEPO method is about 8% shorter than the traditional DPO method. The total number of people who cannot successfully evacuate the DPO method is 270% of the CEPO method. The CEPO method can perform one off-line optimization to obtain the actual optimal fire evacuation path, avoiding the unreasonable phenomenon of the roundabout, and significantly improving the number of people successfully evacuated.

A cover system with automatic extinguishing device for vehicle lithium battery: development and verification

LIU Dexing , LAN Fengchong, CHEN Jiqing, LIU Mengmeng

2019, 29(3): 39-44. doi:10.16265/j.cnki.issn1003-3033.2019.03.007

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In view of the shortcomings in the measures for monitoring and preventing the thermal runaway of vehicle lithium battery, a lithium battery cover system with an automatic extinguishing device was developed.For developing the system, combustion characteristics of a single ternary lithium-ion battery and its main components were measured by carrying out combustion tests, and corresponding temperature and heat release rate curves were obtained. Based on this, the overall design scheme of the cover system was determined, and the fire detection module and fire extinguishing module were selected and designed. Finally, combined with Semenov thermal runaway principle, heat transfer theory and the design requirements of GB50084-2017, the fire extinguishing effect of the cover system applied to a battery pack of an electric vehicle is verified. The results show that the cover system can effectively monitor and extinguish the early local fire of battery pack, and keep cooling to prevent the fire from re-igniting, which has a strong marketing potential.

Experimental study on factors influencing spontaneous combustion of oil containing sulfur storage tanks

YIN Min, LI Zijun

2019, 29(3): 45-50. doi:10.16265/j.cnki.issn1003-3033.2019.03.008

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In order to further study factors influencing spontaneous combustion of oil containing sulfur storage tanks, firstly, four factors including particle size, oil stain, water content and ferric iron compound mass ratio were selected for single-factor experiments to determine the oxidative weight gain rate. And then, based on the orthogonal experiment to verify the influence degree of the interaction between these four factors, the method of range analysis and the method of variance analysis were used to calculate the experimental data. The results show that sulfur corrosion products' particle size, oil stain, water content and mass ratio of ferrous sulfide to ferric sulfide are all important; and the order of importance of single factor influence is the mass ratio, oil stain, particle size and water content, and that the interaction between the mass ratio and oil stain and the interaction between water content and oil stain need to be considered, and the remaining interactions may not be considered.

Study on propagation characteristics of benzene vapor explosion and combustion flame

GAO Jiancun, ZHOU Shangyong, HU Shoutao, WANG Le, SUN Xu

2019, 29(3): 51-56. doi:10.16265/j.cnki.issn1003-3033.2019.03.009

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In order to explore the propagation characteristics of explosion and combustion flame of the benzene vapor, explosion and combustion experiments of different concentrations of benzene vapor were carried out in a self-designed 1m transparent explosion test pipeline. The high-speed camera was used to capture images of flame propagation of benzene vapor explosion in the pipeline. The flame images were compared and analyzed. The results show that a violent explosion reaction occurs when the low concentration of premixed benzene vapor-air gases are ignited, and the violent explosion reaction turns into a mild combustion reaction with the increase of concentration of benzene vapor in the premixed gases. The average flame propagation velocity increases with the rise of benzene vapor concentration, and reaches a maximum when the volume fraction of benzene vapor is 2.8%. Then the velocity decreases with increasing benzene vapor concentration. The propagation process of explosion flame of low concentration benzene vapor can be divided into four stages: a rapid accelerating stage, a rapid decelerating stage, a slow accelerating stage and a slow decelerating stage. The propagation speed of high-concentration benzene vapor flame basically keeps constant, and the flame shape is closely related to flame propagation speed.

Study on peak overpressure prediction of underground blasting shock waves on straight-through roadways

LUO Haohao, LI Xianglong, WANG Jianguo, LI Guangtao, LI Zaili

2019, 29(3): 57-62. doi:10.16265/j.cnki.issn1003-3033.2019.03.010

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In order to reduce the impact of blasting shock waves on underground personnel and equipment, studies were conducted by using the NUBOX-9012 intelligent blasting shock wave monitor and the matched shock wave sensor to monitor the explosion shock wave on site and using the finite element software ANSYS/LS-DYNA to simulate the attenuation process of blasting shock waves on the straight-through roadway. The results of numerical calculations were extracted, the unknown coefficients b₁, b₂, and b₃ in the formula for shock wave peak overpressure prediction on straight-through roadways with one end opening were acquired, and the calculated value was obtained by substituting the original data of different doses at different distances into the prediction formula as compared with the measured value. The results show that the prediction error is within reasonable limits, and the prediction formula are applicable to the prediction of the peak overpressure of shock waves on straight-through roadways.

Study on UGM(1,1) modeling for prediction of pipes corrosion under different initial conditions

ZHANG Xinsheng, YE Xiaoyan

2019, 29(3): 63-69. doi:10.16265/j.cnki.issn1003-3033.2019.03.011

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In order to study the influence of the initial condition for unequal interval grey models(UGM(1,1)) on pipeline corrosion prediction, firstly, the modeling steps of unequal interval pipeline corrosion prediction grey model under different initial conditions were discussed, secondly, aiming at solving the problem of selection of initial conditions in the traditional unequal interval pipeline corrosion prediction grey model, a sliding unequal interval grey pipeline corrosion prediction model (SUGM(1,1,ρ)) under a sliding initial condition was built up by combing the ideas of metabolism and new information priority principle. Finally, the models were used to predict the pipeline corrosion of a certain marine riser as an example, and a comparison was made between the prediction effects of SUGM(1,1,ρ) model and the unequal interval pipeline corrosion prediction grey models under different initial conditions. The effectiveness of SUGM(1,1,ρ) model was verified. The results show that the average relative errors of predicted results obtained by using four unequal interval pipeline corrosion rate prediction grey models under different initial conditions are 3.16%,3.35%,3.49% and 3.36%, and that obtained by using SUGM(1,1,ρ) model is 1.77%.

Impact of axial stress on ultimate internal pressure of corroded pipelines

ZHAO Pengcheng, SHUAI Jian, TANG Yu, XU Kui

2019, 29(3): 70-75. doi:10.16265/j.cnki.issn1003-3033.2019.03.012

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In order to study the influence of axial stress on ultimate internal pressure of corroded pipelines, a three-dimensional finite element model of pipeline was established. The model was verified by the blast test data from the literature. The changes of ultimate internal pressure of pipelines under axial compressive stress and axial tensile stress with different corrosion defect parameters and material parameters were analyzed, and the results were based on the finite element simulation. The formula to predict the ultimate internal pressure of corroded pipeline under axial stress was put forward. The results show that the axial compressive stress will lead to reduction of the ultimate internal pressure, that the effect of axial stress on the ultimate internal pressure of pipelines varies and the smaller the defect size is, the more obvious the effect will be, that the axial tensile stress will result in a slightly higher ultimate internal pressure, and the greater the axial stress is, the more obvious the effect will be, that the higher the yield strength of pipelines with different geometric sizes of corrosion defects is, the less obvious the effect of axial stress will be, and that the established ultimate internal pressure formula is accurate, and it can be used for predicting the ultimate internal pressure of corroded pipelines.

Study on muscle fatigue characteristics of drilled workers in confined space

XU Sheng, JIN Longzhe, XU Mingwei

2019, 29(3): 76-81. doi:10.16265/j.cnki.issn1003-3033.2019.03.013

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In order to study the muscle fatigue characteristics of drilling workers in confined spaces, the sEMG of ten muscles such as splenius cervicis and thoracolumbar fascia was measured under standing posture, semi-squatting posture and full knee posture through the simulation experiments. Using the MF as an indicator, the fatigue degree of each muscle was evaluated according to the MF reduction rate, and different time gradients were set to compare the change of fatigue degree, thereby proposing a solution to reduce muscle fatigue. The experimental results show that the deeper the muscle fatigue degree is, the faster the MF declines, that the waist shows a high rate of decline (0.374±0.129) in all three postures, that the drop rate (0.60) of the neck is higher in the standing position and the drop rate (0.55) of tibial muscle is higher in the kneeling position, and that the adjustment of the working cycle can reduce the MF value by 1.33-9.85 times and effectively reduce fatigue.

Effect of pressure released and permeability improved induced by working face arrangement under long distance coal seam mining

XIAO Jiaping, YANG Ke, LI Zhihua, SUN Zehong

2019, 29(3): 82-88. doi:10.16265/j.cnki.issn1003-3033.2019.03.014

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In order to study the effect of pressure released and permeability improved induced by working face arrangement under long distance coal seam upward mining, according to the geological conditions of the 11223 working face in Panji No.2 Coal Mine, the FLAC^3D numerical simulation software was used to study the distribution character of stress field, displacement field and crack field after the pressure relived mining, and make sure the pressure released and permeability improved area depend on stress relief coefficient under different mining condition. The results indicate that: the working faces were vertically arrangement in the west second segment, the mining of lower 11223 working face can induce remarkable change in stress field, displacement field of upper 11224 working face, the stress relief coefficient is 90.37% in the middle part of 11224 working face, which can make a good stress relief effect. However, in the east first segment, the 11224 working face used the 90 m outward stagger mode in ventilation entry and 90 m inner stagger mode in conveyor entry, the stress relief coefficient is 88.97% in the lower part of 11224 working face, this can make a good stress relief effect, while the stress relief is very feeble in the upper part. To sum up, it can make a better effect of pressure released and permeability improved when working faces apply vertically arrangement under long distance coal seam upward mining.

Simulation modeling analysis of human error probability based on system dynamics

ZHANG Ya, ZHANG Mingguang, QIAN Chengjiang, ZHAO Yao

2019, 29(3): 89-94. doi:10.16265/j.cnki.issn1003-3033.2019.03.015

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In order to deeply study the changes in HEP of petrochemical employees in the face of accidents, based on SD theory and method, a causal map and a system map were drawn for enterprise employees HEP under accidents. Dynamic simulations were performed by using Vensim software to quantitatively analyze the dynamic evolution process of the influence of various factors on corporate employees' HEP. The results show that the change in HEP curve is divided into two different stages with 35 h as the cut-off point, that the main influencing factors before and after the cut-off point are risk cognition and personal safety commitment, and that the trend in the evolution of HEP can be changed by controlling the changes in different HEP influencing factors.

Research on method for calculating three-dimensional stability of slope with inclined weak-layers

WANG Dong,LI Guanghe,CAO Lanzhu,XU Xiaohui,ZHANG Liguo

2019, 29(3): 95-101. doi:10.16265/j.cnki.issn1003-3033.2019.03.016

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For the sake of calculating the exposed length of the slope with inclined weak-layers, and considering the occurrence characteristics of rock mass and the spatial geometry of the potential landslide, a simplified mechanical model was built for the three-dimensional landslide of the slope with inclined weak-layers. The mechanical conditions on the boundary of landslide body were analyzed. A method for the three-dimensional stability of slopes by calculating the exposed length of inclined weak-layers was obtained with the theory of limit equilibrium. The method was verified by CDEM in Baiyinhua 1st open pit mine. The results show that there is a negative correlation between the stability coefficient F_s and the exposed length L of the weak layer in Baiyinhua 1st open pit mine non-working slope, the critical exposed length is about 500 m and the allowable exposure length is about 300 m, and that the exposed length of weak layer determined by this method comforms with the simulation results.

Modeling test based study on roof cutting for pressure unloading in inclined coal seam

DAI Shuhong, LI Shuo, ZHANG Yin, CHEN Chen

2019, 29(3): 102-107. doi:10.16265/j.cnki.issn1003-3033.2019.03.017

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In order to study the effect of the roof cutting position on pressure unloading and the stability of inclined coal seam, geomechanical modeling tests were carried out according to the conditions existing in the working face of Shuangyashan coal mine. Analog materials and model frames were used to simulate the geological structure and the in-situ stress of coal seam. The deformation fields of the coal pillar, coal body and roof before and after the roof cutting were measured in real time by using the digital image correlation method. The experimental study shows that when the roof cutting is carried out at the coal pillar adjacent to the roadway, deformation is concentrated in the roadway and the coal pillar, the overlying strata sank, the tension deformation occurrs in the coal pillar, that when the roof cutting is carried out at the coal pillar adjacent to the goaf, the coarse sandstone and the fine sandstone slid relatively along the boundary interface, but the sliding displacement is small, that when the roof cutting is carried out at a position having a distance of 3 meters to the outer edge of the coal pillar, the coal body on the side of the goaf is plastically deformed, the lateral plastic zone of the coal pillar will have a horizontal displacement, and the roof subsidence will have a little effect on the deformation of the coal pillar, and that the position having a distance of 3 meters to the outer edge of the coal pillar is the best roof cutting position.

Analysis on spatial and temporal characteristics of outburst prevention effect in protective seam mining

GUO Huaiguang

2019, 29(3): 108-113. doi:10.16265/j.cnki.issn1003-3033.2019.03.018

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The paper aims to study temporal-spatial evolution features of outburst prevention effect in protective layer mining area and provide the basis for determining gas drainage parameters and mining sequence. A mechanical modle for underlying rock stress (deformation) was established to carry out the numerical simulation. The spatiotemporal distribution of parameters of protected coal seam was investigated. The results show that main factors influencing spatiotemporal distribution of protection effect are rock quality and structure, coal seam mining thickness and length of mining face, that the distribution of stress of protected coal seam is W-shaped and that of deformation is M-shaped, that with the change of mining face position, the gas pressure firstly increases and then decreases, while the expansion rate and permeability firstly decrease and then increase, and that the change of coal deformation lags behind the advancing of mining face position, which shows the creep characteristics of the coal deformation.

Experimental study on mechanical properties of basalt fiber-reinforced tailings

ZHENG Binbin, ZHANG Dongming, WANG Hao, YANG Han

2019, 29(3): 114-119. doi:10.16265/j.cnki.issn1003-3033.2019.03.019

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In order to improve the stability of tailings dam, a method for enhancing the mechanical properties of tailings by fiber reinforcement was worked out. Triaxial experiments and scanning electron microscope (SEM) tests were carried out to systematically study fiber reinforcement effect and fiber action mechanism. Firstly, a classified tailings material from Yunxi company as taken the test sample, basalt fiber was taken as an ideal reinforcement material for the tailings, and basalt fiber was added to tailings slurry, and then a fiber reinforced tailings specimen was formed after tailings natural deposition. Then, a triaxial test of the specimen was carried out to study the effects of dry density on the mechanical properties of the specimen. Finally, the interfacial interaction between basalt fiber and tailings particles were analyzed by SEM from a microscopic point of view. The results show that the basalt fiber can enhance mechanicalproperty of tailings, that the shear strength of reinforced tailings increases with the increase of both dry density and confining pressure, and that the coarser the tailings particles are, the better the reinforcing effect.

Study on optimization of borehole sealing parameters based on extraction drilling spontaneous combustion control

QI Yun,QI Qingjie,LYU Youchang,ZHOU Xinhua,CHI Yuchun

2019, 29(3): 120-126. doi:10.16265/j.cnki.issn1003-3033.2019.03.020

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To solve the problem of spontaneous combustion of boreholes caused by poor sealing of boreholes in bedding extraction in No.10 Coal Mine of Pingdingshan Coal Mine, the stress distribution characteristics of surrounding rock of roadway were studied by means of drilling cuttings method, the leakage passage around boreholes and the conditions leading to spontaneous combustion of boreholes were analyzed in depth, and distribution of air leakage velocities around boreholes as a function of both sealing depth and sealing condition was simulated by using the Comsol Multiphysics software. Optimum sealing parameters were obtained and their effects on gas extraction were discussed. The results show that 0-7 m away from the roadway is the broken area, 8-19 m is the plastic area, 20-28 m is the elastic area, the broken area around the roadway, the air leakage around the borehole, the air leakage of sealing material and the air leakage of the extraction pipeline are the air leakage ways of the borehole, providing the ventilation and oxygen supply conditions for the spontaneous combustion of the borehole, that when the sealing depth is 17 m, the sealing length is 8 m, the maximum negative extraction is achieved, and when the pressure is less than 30 kPa, it can not only guarantee the effect of drainage but also prevent the spontaneous combustion of boreholes, and that volume fraction of single hole gas drainage reaches 70% after optimization of sealing parameters, which can effectively prevent spontaneous combustion of drainage holes.

Study on danger in graphene oxide preparation process based on reaction calorimetry

ZHOU Yu, SU Lei, XIE Chuanxin

2019, 29(3): 127-132. doi:10.16265/j.cnki.issn1003-3033.2019.03.021

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In order to reduce the risk in the preparation process of graphene oxide, experiment were carried out. RC, DSC, SEM, EDS and other instruments were used to explore the cause of heat release during the process and study effects of the stirring speed, the feeding time, the feeding temperature and the reaction temperature in the middle temperature stage and other parameters on the heat release. Orthogonal tests were designed and performed to obtain the relevant kinetic parameters under different conditions. Finally, according to the orthogonal analysis of the kinetic parameters, optimal conditions for the preparation process were obtained. The results show that the exothermic cause is accumulation and rapid decomposition of potassium permanganate, that the reaction temperature in the middle temperature stage is an important factor in controlling the risk in the process of preparing graphene oxide, and that a operating condition having a stirring speed of 250 r/min, a feeding time of 60 min, a feeding temperature of 0 ℃, and a reaction temperature of 20 ℃ in the intermediate temperature stage is the optimum operating condition.

Research on sealing technology of screen pipe based on creep deformation

ZHANG Qi, WEI Guoying, QIN Binbin, LIU Wei, WANG Junming

2019, 29(3): 133-138. doi:10.16265/j.cnki.issn1003-3033.2019.03.022

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In order to solve the problem of low extraction flow rate and concentration caused by borehole deformation in the process of extraction, theFLAC^3D software was used to build a deformation model of coal body around the borehole based on creep law, and the creep displacements and plastic-zone shape change of coal body around conventional and preset screen pipe were compared and analyzed. The technology of sealing hole inner screen extraction was put forward to improve the borehole support force and ensure the borehole extraction section, and the industrial test was carried out. The results show that after the completion of the borehole, the hole wall is affected by the circumambient pressure, and the coal body presents the creep pressing characteristics towards the direction of borehole, that compared with conventional borehole, the shape variable of sieve tube drilling is obviously smaller, and that after adopting the sealing technology of preset screen pipe extraction, on the 65 day of extraction, the volume of extraction increases by 191% and concentration increases by 137% compared with the conventional sealing technology, and the extraction efficiency is significantly improved.

Experimental study on influencing factors of water mist charge removal of PM_2.5

GE Shaocheng, SUN Liying, JING Deji, CHEN Xi, CHEN Jingxu, GUO Jiace

2019, 29(3): 139-144. doi:10.16265/j.cnki.issn1003-3033.2019.03.023

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To solve the problem of difficult removal of PM_2.5, an orthogonal experiment was designed to effects of charge-characteristics of water mist and dust-laden air velocity on efficiency of PM_2.5 removal were studied by carrying out orthogonal experiments. Experimental data were processed by the analysis method of linear regression. A regression model was built for PM_2.5 removal efficiency. The results show that the regression model is an effective one and can be used to predict the efficiency of PM_2.5 removal, that when the charge voltage(x₁) is 12 kV, electrodes distance(x₂) is 15 mm, electrode ring diameter(x₃) is 60 mm, gas-liquid ratio(x₄) is 1.5, nozzle diameter(x₅) is 0.6 mm, dusty airflow velocity(x₆) is 4 m/s, the optimal value of PM_2.5 removal efficiency is 97.26%, that there is a positive correlation between factors-x₁, x₂, x₄ and PM_2.5 removal efficiency, and a negative correlation between factors-x₃, x₅, x₆ and PM_2.5 removal efficiency, and that the importance ranking of factors is x₁>x₆>x₄>x₅>x₃>x₂.

Research on mining types of safety hidden dangers in coal mine based on text clustering

TAN Zhanglu, WANG Zhaogang, HU Han, JIANG Xuan, PENG Shengnan

2019, 29(3): 145-148. doi:10.16265/j.cnki.issn1003-3033.2019.03.024

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In order to enhance the ability of coal mine safety administrators to understand and process hidden danger data, and improve the work of hidden danger investigation and management,the text clustering method was applied to mining and analyzing the data of historical safety hazards records of coal mining enterprises.The chi-square statistics was used to extract feature words,and the feature words with high degree of correlation with category were used to describe the clustering results.The main types and characteristics of hidden dangers recorded in historical data were studied.The results show that the combination of text clustering and chi-square statistics could identify the types and characteristics of the main hidden dangers recorded in the data on coal mine safety hazards and that the serctor in coal mine responsible for investigation and treatment of hidden dangers should focus on the hidden danger types with large numbers, and formulate corresponding treatment measures according to the characteristics of hidden danger types, so as to improve the pertinence and effectiveness of the investigation and treatment of hidden dangers.

Measurement model for coal mine safety integrity

WEI Zhijie, YIN Tengfei, WANG Lijie

2019, 29(3): 149-154. doi:10.16265/j.cnki.issn1003-3033.2019.03.025

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The paper was aimed at precisely evaluate safety integrity of coal mines. Firstly, on the basis of analysing related research results, four evaluation dimensions were determined: safety integrity culture, management system construction, education and training, and safety supervision. Secondly, a measurement model was established based on these four dimensions, and the questionnaire was made according to the Likert five-level scale technology and several observational variables. Then two coal mines of Jizhong Energy Group Company were taken as samples to conduct survey, and survey data was obtained to verify the model. Finally, the CFA method was used to process data. The results show that sample data matches well with the measurement model and observational variables can describe latent variables, and that the four evaluation dimensions can reflect the management level of coal mine safety integrity.

Research on coupling of safety information in accidents

LUO Tongyuan, WU Chao

2019, 29(3): 155-160. doi:10.16265/j.cnki.issn1003-3033.2019.03.026

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In order to provide new ideas and methods for emergency response to and prevention of accidents, the transmission of safety informationin in accidents was studied by coupling analysis theory. Firstly, the concept of safety information was proposed from the perspective of safety informatics, and the necessity of applying the coupling theory to the propagation and evolution of safety information was analyzed. Then four characteristics of accident safety information were defined based on the essential law of safety information. At the same time, 24 basic coupling factors influencing safety information were expounded from the aspects of enterprise, government and society. Finally, according to the literature and coupling factors, the coupling effect path diagram of safety information in accidents containing 9 key points and 42 paths was established, on which the basic coupling model of safety information was built. The results show that the coupling mechanism of safety information in accidents has guiding significance for the coupling effect and evolution model of safety information, and provides a theoretical basis for accident emergency response and prevention based on safety information.

Multi-hazard comprehensive risk assessment based on coupling incentive mechanism

WANG Wei, XIA Chenhong, MA Donghui, SU Jingyu

2019, 29(3): 161-167. doi:10.16265/j.cnki.issn1003-3033.2019.03.027

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In order to solve the problems of neglecting the interaction between multiple disasters and lacking guidance for urban land use planning in regional comprehensive risk assessment of multiple disasters, a comprehensive risk assessment model was built for multiple disasters based on coupling incentive mechanism. The central area of Shijiazhuang city was taken as the research object. Firstly, GIS was used to obtain typical disaster information such as geology, earthquake, fire, flood, and waterlogging. Then, the spatial coupling incentive rules between disasters were constructed. Finally, the integrated risk assessment of multi-hazards was carried out by using the ordered weighted set of settlements. The results show that the areas of extremely high, high, medium, low and extremely low risk areas account for 26%, 19%, 31%, 21% and 3% respectively. Among them, the areas with high comprehensive disaster risks are mainly concentrated along Hutuo River, the periphery of major hazard sources and Shijiazhuang fault zone, which are distributed in clusters. The obtained research results are highly consistent with the actual situation, indicating that the incentive model can accurately integrate various disaster information and overcome many uncertain problems, thus effectively realizing rapid and flexible comprehensive disaster risk assessment for cities.

Evaluation method of ship navigation safety in routing waters based on stream reasoning

WEI Wanqi, GAO Shu, CHU Xiumin

2019, 29(3): 168-173. doi:10.16265/j.cnki.issn1003-3033.2019.03.028

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In order to use the data of personnel, ship, environment and management during ship navigation more effectively and conduct real-time assessment of navigation safety, this paper proposed a method for evaluating ship navigation safety based on SR in routing waters. Firstly, the safety assessment elements of ship navigation were reduced based on RSCIE and the assessment ontology was constructed by combining expert knowledge. Then the ship navigation-related streaming data collected in real time was integrated by semantic Web technology, and the SR engine was used to infer the navigation safety. Finally, the ship navigation safety in a certain routing water system in Nanjing was evaluated and the method presented in this paper was compared with the other two methods based on cloud theory. The results show that the proposed method has better timeliness, higher detection rate and lower false alarm rate.

Conflict coordination model for emergency decision making in disaster accidents

XIA Dengyou, GAO Ping, REN Shaoyun, ZHU Hongwei, ZHANG Yunbo

2019, 29(3): 174-179. doi:10.16265/j.cnki.issn1003-3033.2019.03.029

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For the sake of resolving conflicts in emergency decision making process of disaster accidents, a model of conflict coordination for decision-making was established. Firstly, according to the relationship between conflict and consistency, a representation method for conflict degree of emergency decision making was proposed based on the fuzzy logic theory, and the conflict threshold was determined. Then the conflict coordination strategies were proposed and the steps of conflict coordination were designed in combination with actual situation of conflict. Finally, the rationality and feasibility of the model were verified through an actual case. The study indicates that this model can fully reflect experts' preferences in emergency decision making, quantify the degree of conflict, and could coordinate and eliminate the conflict among decision makers.

Emergency evacuation path optimization model under multi-export conditions

ZHENG Xiazhong, CAI Lili, ZHANG Ming, JIN Lianghai, CHEN Yan

2019, 29(3): 180-186. doi:10.16265/j.cnki.issn1003-3033.2019.03.030

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To reduce the probability of congestion, considering the characteristics of evacuation route selection under multi-export conditions, an emergency evacuation route optimization model is established. Firstly, based on the evacuation channel arrangement orientation, the evacuation network is established, and the feasible evacuation path set is determined. Considering the dynamic relationship between crowd flow and queuing time, the population lag time is calculated, the path equivalent length is characterized, and the iterative feasible path set is represented. Then aiming at the shortest total evacuation time, the Dijkstra algorithm objective function is modified, the time search optimal path is globally, and the evacuation scheme is allocated. Finally, taking the multi-egress floor case as an example, the total time of the shortest and optimal evacuation path evacuation is compared to verify the validity of the model. The results show that the total time of queuing and the total evacuation time of the optimized evacuation scheme are smaller than the traditional evacuation model. The utilization of evacuation exit is higher, the distribution of people flow is more even, and the probability of overlapping of evacuation paths is smaller, which effectively improves the evacuation efficiency.

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