Research on recognition of roadway roof rock layer interface based on sound pressure response characteristics of drilling

Currently, rock coring and borehole imaging are widely used in the field of rock formation detection in coal mines.However, the rock coring is time-consuming, laborious, and it is very difficult to obtain rock samples with weak interlayers.The borehole imaging method is greatly affected by subjective factors, and the imaging is not clear due to the harsh environment.A new method for rapid identification of rock formation interface based on the drilling response characteristics of sound pressure is proposed in this paper.Cement, sand, loess, and water are mixed into concrete specimens with three different strengths in different proportions, and the sound pressure of each specimen is collected during the drilling process with a sound pressure recorder.And the field test is carried out in 504 return airway in a mine.The following conclusions are drawn.The sound pressure increases as the strength of the drilling specimen increases.The sound pressure changes little during drilling in different specimens, and there are certain fluctuations in the sound pressure when drilling in the same specimens.The recognition error of coal-rock interface with drilling sound pressure as a single indicator is up to 15 cm, but it provides a new method for rock formation recognition.Measurement while drilling is the main direction of intelligent rock formation detection.These research conclusions provide references for follow-up scholars.