EXPERIMENTAL RESEARCH ON THE ULTRASONIC TECHNIQUE AND ITS APPLICATION IN STUDYING ROCK PROPERTIES

The experimental installation and measurement system of ultrasonic wave property in rocks during complete stress-strain process were established and perfected. The interrelations between ultrasonic wave property of mudstone,sandstone and limestone specimens during complete stress-strain process and their mechanic property were investigated. A new type of device for the observation of surrounding rock stability--borehole ultrasonic device with completely dry coupling was developed to get better coupling and more accurate measurement data comparing with those of water coupling situation. Preliminary study on the application of ultrasonic measurement technique at belt conveyor roadway of north wing in Baodian Coal Mine (Shandong province) was conducted. Based on the interrelations between the complete stress-strain properties of specimens and their wave properties, the structural properties of surrounding rocks, the range of yield zones,and the change of stresses within surrounding rocks when a Iongwall face was across over the roadway were analyzed. Therefore,a new and feasible way was found for the research on the deformation law of surrounding rock of roadway and rational selection of support parameters.

The experimental installation and measurement system of ultrasonic wave property in rocks during complete stress-strain process were established and perfected. The interrelations between ultrasonic wave property of muds tone, sands tone and limestone specimens during complete stress-strain process and their mechanic property were investigated. A new type of device for the observation of surrounding rock stability-borehole ultrasonic device with completely dry coupling was developed to get better coupling and more accurate measurement data comparing with those of water coupling situation. Preliminary study on the application of ultrasonic measurement technique at belt conveyor roadway of north wing in Baodian Coal Mine (Shandong province) was conducted. Based on the interrelations between the complete stress-strain properties of specimens and their wave properties, the structural properties of surrounding rocks, the range of yield zones, and the change of stresses within surrounding rocks when a longwall face was across over the roadway were analyzed.Therefore,a new and feasible way was found for the research on the deformation law of surrounding rock of roadway and rational selection of support parameters.