Experimental study and field application of charge induction law in coal rock deformation and failure

Abstract

It is of great significance to accurately grasp the charge induction law of rock mass during load failure process for the prediction of dynamic disasters such as rock burst. On the basis of optimizing and improving the acquisition accuracy of charge monitor, laboratory monitoring tests were carried out on the charge induction rule of sandstone samples under uniaxial compression failure under load, and underground monitoring tests were carried out. The relationship between charge induction, stress drop and crack growth of sandstone samples under different loading rates and the charge induction characteristics in the area affected by abutment pressure of advanced working face were analyzed in detail. The research shows that: the formation, development and propagation of cracks are accompanied by charge induction signals during the process of loading failure, and the generation of precursor charge signals is earlier than the stress drop caused by loading failure. Under the loading rates of 0.005 mm/s, 0.015 mm/s and 0.020 mm/s, the law of charge signal in the failure process of rock samples varies with the loading rate. The higher the loading rate is, the richer the charge signal is, and the precursory charge signal appears more early. Field monitoring found that the maximum value of the average induced charge at each measuring point was located in the influence area of the advanced abutment pressure, and the average induced charge was consistent with the distribution trend of the advanced abutment pressure on the working face.

Keywords

• charge monitoring instrument
• rock mass failure
• charge induction
• charge signal
• non-contact prediction