CONTROL METHOD OF THE ROCK MASS STRESS CONDITION IN THE VICINITY OF WORKING Russian patent published in 2017 - IPC E21C39/00 

FIELD: mining.

SUBSTANCE: scanning is performed by ultrasonic stationary noise signals with the average equal to zero mass sections, located between parallel wells along its depth. The ultrasonic signals reception is carried out by two acoustic transducers, which at each of the scanning sections are located symmetrically relatively to the axis of the emitted acoustic transducer radiating pattern main lobe. Measure the correlation intervals and the cross-correlation coefficient of the signals from the receiving transducers outputs, increasing its clamping force to the well wall until the measured correlation intervals increase is stopped. The values of the measured cross-correlation coefficient are fixed after reaching the specified moment in each section and the graph of this coefficient versus the depth is plotted. The depth, from which the cross-correlation coefficient obtains the constant value, is taken as the abutment pressure zone limits, and the depth, from which the cross-correlation coefficient is less than the specified value, is taken as the stress relief zone limit. The depth, at which the maximum value of the cross-correlation coefficient takes place, corresponds to the maximum stress in the abutment pressure zone.

EFFECT: determination of the stresses spatial distribution in the vicinity of the mine workings and the abutment pressure zone maximum depth.

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