The Study Of Ultrasonic Differentiating Theory And Measure For Coal Structure Types

The disaster of coal and gas outburst is serous in China. In these years with the increasing of coal production and exploitation depth, the frequency of the disaster is higher and it has badly affected the order of coal production. So how to effectively forecast the disaster is imminent. Practice has been proved that the necessary condition of coal and gas outburst is the existence of coal structure (coal ofâ…¢&â…£),so the disaster can be forecasted by exploring coal structure in coal bed or not. This paper brings forward a new method of exploring and differentiating coal structure types. By studying the exploring theory, models of calculating ultrasonic speed and ultrasonic attenuation coefficient in coal have been set up. Models have achieved the measure of ultrasonic speed and ultrasonic attenuation under the condition of multilayer and the relation between coal structure types and ultrasonic attenuation coefficient has been proved by experiments. Then the differentiating model of ultrasonic and BP neural network has been set up .The model is typical three-layer structure and in the model the input judging indexes are ultrasonic speed, ultrasonic attenuation coefficient and ultrasonic work frequency, the output indexes are coal structure types. By analyzing these indexes, coal structure types can be made exact estimation. These theories and models are proved to be reasonable and correct through experiments, BP neural network have been verified by the checkout data. In a word, this paper has made in-depth studies at ultrasonic quality, exploring project of coal structure types and theory modeling. And these studies have offered theory basis to exploring system of exploiting coal structure types for the future.