Internal Mechanism of Reducing Rockburst Proneness of Rock Under High Stress by Real-Time Drilling Pressure Relief

To investigate the internal mechanism of drilling pressure relief (DPR) to reduce the elastic strain energy of deep rock, SG4500 equipment that can realize real-time drilling under high stress was independently developed. Real-time drilled (RD) uniaxial compression experiments were conducted on red sandstone specimens under different stress levels, and then the influence of real-time drilling on the weakening of rockburst proneness was studied. For comparison purposes, uniaxial compression tests were also performed on non-drilled (ND) and prefabricated drilled (PD) rock specimens. The results demonstrate that both prefabricated drilling and real-time drilling under high stress can effectively weaken the mechanical behavior of rock and reduce the storage capacity of the elastic strain energy and rockburst proneness of rock. Compared with ND specimen, the energy storage coefficients of PD and RD specimens were reduced by 1.01% and 5.16%, and the rockburst proneness index was reduced by 5.15% and 19.32%, respectively. The failure intensity of PD and RD specimens was also weaker than that of ND specimen. However, compared with prefabricated drilling, real-time drilling under high stress can more accurately reflect the change in the rock energy state. The energy storage coefficient and rockburst proneness index of RD specimen were decreased by 3.8% and 14.9% compared to those of PD specimen, respectively. Furthermore, it is also found that drilling energy relief (DER) is a significant feature of real-time drilling under high stress to prevent rockburst, which further demonstrates the effectiveness of DPR in reducing rockburst proneness from an energy perspective.