Introduction Environmental pollution is causing widespread concern in all countries of the world and has become one of the global problems that must be solved in the survival and development of human society. Noise has become an important source of pollution, and noise control has become an important discipline. The so-called noise is a sound that makes people sound unpleasant and people don't need it. Noise is annoying, hearing damage, and hinders language communication and other necessary sounds. Long-term operation in a noisy environment can cause obstacles in the cardiovascular system, nervous system, and digestive system, and of course, affect people's work and productivity. In the production of stope, due to the high power, equipment and serious noise of the machinery and equipment, it seriously affects the production and life of the workers. It must be analyzed and controlled to promote the safe and comfortable conversion of the stope environment and protect the health of workers. And improve the reliability of the system.
1 Measurement and analysis methods of stope noise
1.1 Measurement of noise 1 Sound pressure level The sound pressure level is expressed as:
In the world, the sound pressure P0 that can be heard by the human ear is set to 0 dB, and the hearing range of the human ear is 0-120 dB.
2 Calculation of the overall sound pressure level of the sound source environment in the stope In the work environment, there are multiple noise sources, and it is necessary to understand the relationship between the sound pressure level of each sound source and the overall sound pressure level. According to the principle of energy synthesis:
Let there be several sound sources at a certain point. The sound pressure levels generated at a certain point are L1,...Ln, respectively. If the sound pressure of each sound source is P1...Pn, then
3 The influence of noise on the language communication of the working face: Noise has a masking effect on language communication. In order to obtain correct language and auditory information in a noisy environment, the language-noise ratio L(S/N) is usually used in the stop face. In terms of measurement, L (S/N) is generally required to be greater than 10 dB.
In the case of different signal-to-noise ratios in a working face of the stope, the frequency table for observing the blocking communication once and correctly listening to the other party's instructions is shown in the table below.
1.2 Using fuzzy mathematics to establish the membership function of the noise factor of the stope:
Taking the sound pressure level domain U=[0,90], the unreasonable membership function can be expressed as follows:
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