Study On Musculoskeletal Fatigue Injurymechanism And Working Postureoptimization Of Bolt Support Workers

The long-term operation of bolt support workers in a poor ergonomic environment not only reduces the work comfort and efficiency of the bolt support workers,but also directly affects the musculoskeletal health of the bolt support workers.Based on the theories of safety ergonomics and ergonomics,this thesis adopts theoretical analysis,software simulation and experimental research methods to study the musculoskeletal fatigue damage and working posture optimization of underground bolt support workers in order to improve the comfort of support operations,and ensure that underground coal production is carried out safely and efficiently.Firstly,according to the technical process of supporting operation in fully mechanized excavation face,the posture characteristics of bolt supporting operation are analyzed and determined,and the ergonomic influencing factors of supporting operation are obtained.From the four aspects of bolt working posture,physical load,working environment and labor organization,the characteristics of musculoskeletal fatigue injury of bolt support workers were investigated and researched.Logistic regression univariate analysis was used to determine the ergonomic factors and their degree of influence significantly related to MSDs in the waist,neck and shoulder.Secondly,JACK software is used to conduct simulation research on four ergonomic factors,including neck posture,operating distance,work load and rest between work stations.Human factor analysis tools such as lower back analysis,NIOSH force analysis,comfort value analysis,and metabolism analysis were used to analyze fatigue damage,and determine the influence characteristics of fatigue damage of four factors.Thirdly,the surface electromyography was used to measure the fatigue injury of neck muscles,and to explore the fatigue injury law of neck muscle fatigue injury with the change of activity angle and working frequency.The active muscle of neck flexion is the sternocleidomastoid muscle,the active muscle of neck extension is the clip muscle,the comfortable range of motion of the neck muscle is-15°～15°.During high-frequency operation,the muscle fatigue speed is accelerated,and the main neck muscle fatigue occurrence time is advanced from 16-19 minutes to 13-17 minutes,and the continuous operation time is kept at about 30 minutes for rest,which can effectively relieve neck muscle fatigue.Finally,based on the comprehensive analysis results,the improvement of musculoskeletal fatigue damage and the optimization of working posture of bolt support workers are proposed for neck posture,operating distance,work load,and rest between work.