Study On Characteristics Of Ground Obstacles And Perceived Tripping Risk In Dark Environment

Falls are the second leading cause of unintentional injury death after road traffic injuries,and most fall-related injuries are non-fatal.Most falls are caused by obstacles.An experimental study was conducted on miners of special jobs and special populations to explore the influence of surface obstacles characteristics in dark environment on perceived tripping risk.The specific study is as follows:(1)In order to study the influence of environmental factors on the perception of the risk of tripping,this research was performed under the lighting conditions,walkway,obstacle types,obstacle colors,and obstacle height conditions.There were two blocks in the experiment: light and dimmed conditions.Two floors were prepared for the walkways in the gait experiment.Two types of obstacles,namely plates and rods,each with five different heights and two different colors(black and white)were arranged.The subjects rated RRT both before and after they walked.The experimenter recorded RD(Rating of disturbance)and time of the walk after each trial.The results showed that the illumination conditions,obstacle types,obstacle color and obstacle height all had significant effects on both the RRT and gait disturbance score.The color of obstacles and floors also affected the RRT significantly.The probability of contacting obstacles under the dimmed conditions was 15 times of that in the normal lighting conditions.(2)In order to study the influence of the mine environment on the subjective score of the miners' risk of tripping,the factors such as the lighting location and the visible structure of the obstacle(the depth,number and height of the obstacle)were explored through experiments.The experiment under low light conditions,prepared a floor as experimental trails,set up two depth and three height of obstacles,the number of obstacles have 1,2,or 3.The subjects were given a receptivity of risk of tripping(RRT)before and after walking,and the experimenter gave the subjects' rating of gait disturbance(RD)and recorded the walking time.Data analysis shows that the lighting location and the height of obstacles have a significant impact on the RRT(pre),the lighting location and the number of obstacles have a significant impact on the RRT(after),and the lighting location and the number of obstacles have a significant impact on the RD level.When the starting light is on,the number of times of encountering obstacles accounts for 72.7% of the total number of times of encountering obstacles.(3)Orbit for further research of coal mine complex environment for miners stum-bled subjective risk score,the influence of coal mining is simulated design walking track lane channels(including sidewalks and orbit),the trajectory simulation is 600 cm long,60 cm wide,at the end of the first long distance but the centerline orbit for fixed distance 28 cm,the rest of the sleeper spacing is 55,65,and 75 cm,with light means has two methods of holding the head lamp,marching direction(and orbital direction Angle)is 0 °,30 ° and 90 ° respectively.The results showed that the influence of lamp holding mode on RRT and RD was not significant.Walking mode has a significant effect on RRT(before),RRT(after)and the average value of RD,while the effect on RRT(before),RRT(after)and RD is not all 0.The influence of gauge on RRT(before)and RRT(after)is not significant.The gauge has a significant effect on the average value of RD.This paper has 18 figures,26 tables and 87 references.