A new method for characterization of stress concentration degree of coal mine roadway surrounding rock

Abstract

An accurate assessment of the stress concentration of the surrounding rock is crucial for ensuring safety in underground coal mines with a high potential for rockburst accidents. Traditional methods for measuring the stress of the surrounding rock use borehole stress monitoring equipment and drilling and cutting methods. However, these methods do not always yield accurate and reliable data. In this study, we aim to explore the feasibility of a novel approach for characterizing stress concentration in surrounding rock using monitoring while drilling (MWD) technology during large-diameter drilling. This study combined microseismic monitoring to collect vibration signals during the drilling process and collection of pulverized coal samples at each drilling stage. We analyzed the amplitude, number of coal vibration events and proportion of coarse pulverized coal. By integrating these indices, we characterized the stress concentration in the surrounding rock. Our approach was validated by comparing accurate, stable, and representative data from deep- and shallow-hole stress gauges installed in similar locations and data from the conventional drilling cutting method. Our findings indicate that the proposed method provides a reliable and effective alternative to traditional techniques during large-diameter drilling. The proposed approach can significantly enhance safety management in underground coal mines prone to rockburst accidents.