Evolution and Control Mechanism of Rockburst in Rock Anchored by New Energy-Absorbing Material

The essence of rockburst is the sudden release of energy accumulated in the rock. High-strength energy-absorbing anchoring bolt is an effective means for rockburst control. We conducted rockburst tests on the intact rock and rocks anchored by a new type of energy-absorbing material with high-strength, high-elongation, and high-energy-absorbing characteristics. Subsequently, we analyzed the damage evolution and acoustic emission characteristics of the intact, single-anchored, and double-anchored rocks. Then we explored the control mechanism of the constant-resistance energy-absorbing (CREA) bolt to rockburst. Our experimental results show that the rockburst process includes two stages: gradual damage stage and accelerated damage stage. The time and stress at the beginning of the damage acceleration are about 80% of the rockburst time and peak stress. Compared with the intact rock, the high-amplitude and high-energy signals are significantly reduced in the rocks reinforced by the CREA bolts, indicating that the CREA reinforcement can effectively control the energy release from rockburst. Considering rockburst energy criterion, we find that the rockburst peak stress in single-anchored and double-anchored rocks is 2.0 times and 2.2 times of the uniaxial compressive strength, respectively. The energy required for rockburst in these two anchored rocks is increased by 15.8% and 37.1%, respectively, compared with the intact rock. Therefore, CREA reinforcement can effectively reduce the risk of rockburst. The findings from this work can provide a reference for designing energy-absorbing reinforcing system for rockburst prevention in underground engineering.