Research On Noise Influence On Operators Within Fully-mechanized Mining Faces

Fully-Mechanized Mining Faces is a complicated production system composed by operator,machinery,and environment.Operators are always suffering from noise pollution in this complicated system.Security accidents are prone to occur under excessive noises due to the physiological and psychological instability and uncontrollability of the operators.Therefore,this research,which studied on influencing relations to operators caused by fully-Mechanized Mining Faces noises,is greatly significative in effectively preventing accidents and upgrading the safety level of production.Environment-operator relation under noises of fully-mechanized Mining Faces and noise alarm system is systematically analyzed under the guided of safety engineering and man-machine environment system engineering,through adopting methods like theoretical analysis,Field Testing,laboratory experiments,and data model.On the foundation of researching on noises of fully-mechanized mining faces by utilizing the data model to analyse feature of noise reduction affected by multiple factors in tunnel;formulating the regression equation of noise and human Indicators of both physiological and psychological through laboratory simulations;obtaining the safety operation timetable for different types of work according to consideration of specific mine;adopting the Monte-Carlo method to build the operators’ reliability model under noises of fully-mechanized Mining Faces based on performance function,and set up nice alarm system of fully-mechanized Mining Faces based on operators’ reliability.The significant achievements and conclusions of this thesis are as follow:(1)During the operating,the frequency of noise in fully mechanized mining faces maintained between 3 kHz and 11 kHz for most of the time,with most of the noise is medium-high frequency and high-frequency;the sound pressure level maintained around 75 dB-105 dB,and the highest could reach 105 dB-110 dB.The sound pressure level of the noise sources from the main machinery and equipment exceed the requirement in Coal Mine Safety Regulations,which is 85 dB for the noise limit.Operators in the working face have suffered to industrial noise in their daily work.(2)The noise attenuation follows the rules as below: when the receiving point is close to the sound source,the attenuation is fast and close to the linear attenuation.When the cross-section area of fully mechanized mining faces is fixed,the change rate of the cross-section shape to the sound pressure level appears not much difference,Except for trapezoidal,when the cross-section is trapezoidal,the attenuation of the sound pressure level performs faster.The cross-section area of fully mechanized mining face has dramatically influenced on the sound pressure level.The larger the cross-section area is,the faster the attenuation will be;the sound absorption coefficient of coal and rock mass in the tunnel has an effect on the sound pressure level,and the size of the sound absorption coefficient is positively correlated with the change rate of the sound pressure level.The larger the sound absorption coefficient is,the higher the change rate of the sound pressure level is.(3)Through research on affections of noise pollution in the laboratory,we found that the testers’ physical and psychological indicators are affected by levels of noise stimulation and period of exposing in noise pollution;when the noise level ≤95dB,the exposing period is the leading factor for testers’ physical and psychological indicators;when the noise level>95dB,the noise level is the main factor.(4)Taking fully mechanized mining face of actual mine as examples,we studied on indicators of the workers that affected quite much by the noise pollution,which are coal engine drivers,transport engine drivers,and pump station drivers.According to the GM(1,1)model of the grey theory,the change rule of the physiological index with time could be concluded.According to the threshold of the physiological index defined by medical science,the safe working time of workers in each type of work was calculated as 6.4 hours,6.0 hours and 5.7 hours,respectively.At last,due to the minimum principle,5.7 hours are selected as the safe working time under the noise working environment of fully mechanized mining face,which provides a theoretical basis for the noise working time of miners.(5)A human reliability model based on performance function was proposed.By adopting the Monte-Carlo method in modeling,the human reliability under the noise pressure level range of 50 dB-70 dB,70 dB-90 dB,and 90 dB-110 dB is 1,0.7092 and 0 respectively.(6)Based on the Domino platform of IBM and the theory of early warning system,a safety early warning system for workers in underground noise environment is established with the reliability model as the mathematical core to realize the early warning and forecasting function of workers behavior reliability.