Evaluation of the rockburst proneness of red sandstone with prefabricated boreholes: an experimental study from the energy storage perspective

Abstract

To reveal the function of drilling pressure relief (DPR) in preventing rockbursts from the energy storage perspective, we investigated the rockburst proneness of red sandstone with different number and arrangement of prefabricated borehole via uniaxial compression tests. The experimental result revealed the failure intensity characteristics of specimen can be quantitatively described using the peak-strength strain energy storage index (PESI). The PESI of red sandstone specimens with boreholes decreased by 23.2%–70.2% compared with that of intact specimens, i.e. DPR can effectively reduce the rockburst proneness of rocks. Furthermore, the effects of the number and arrangement of boreholes on rockburst proneness were evaluated. The PESI decreased as the number of boreholes increased. When the arrangement angle with the loading direction changed from 90° to 27° and then to 0°, the PESI first decreased and then increased; when the arrangement angle with the loading direction was 27°, the efficiency of eliminating rockburst proneness and weakening peak compression strength was the best. The borehole arrangement angle affects rockburst proneness more than the number of boreholes does. This paper offers a novel approach of quantitatively evaluating the rockburst proneness of rocks after DPR and clarifies the effectiveness DPR in reducing the probability of rockbursts.

Keywords

• rockburst
• rockburst proneness
• drilling pressure relief
• peak-strength strain energy storage index
• linear energy storage law