Abstract To evaluate the support effectiveness of active rockboltanchor bolt-based active support systems in rock? burst-prone tunnels, a case study was conducted based on the Jiulingshan Tunnel. The secondary stress on tunnel walls and rock strength were obtained using the stress relief method and point load test. A comparative analysis of the suitability of rockburst prediction criteria was carried out, along with inversion of the initial stress field of the tunnel. Based on these results, the rockburst suppression mitigation effects of active and passive support systems were compared from the perspectives of stress and energy. Additionally, the key parameters of active support systems under varying different rockburst gradelevels were explored. The findings indicate the followingthat: (1) Compared to passive support, the active support system can significantly reduces the maximum value of σθ /Rb around the tunnel the maximum stress around the tunnel and suppresses the intensity of rockburst intensityoccurrences. The"energy absorption and release" effect of the active support system is more pronounced, aligning better with the principles of rockburst mitigation; (2) Increasing rockbolt anchor bolt strength and decreasing rockanchor bolt spacing both can improve the performance of the active support systems in mitigating rockburst; (3) For medium and intense rockburst scenarios, enhancing rockbolt anchor bolt strength proves to be more effective and economical than reducing rockbolt anchor bolt spacing.
Abstract：
To evaluate the support effectiveness of active rockboltanchor bolt-based active support systems in rock? burst-prone tunnels, a case study was conducted based on the Jiulingshan Tunnel. The secondary stress on tunnel walls and rock strength were obtained using the stress relief method and point load test. A comparative analysis of the suitability of rockburst prediction criteria was carried out, along with inversion of the initial stress field of the tunnel. Based on these results, the rockburst suppression mitigation effects of active and passive support systems were compared from the perspectives of stress and energy. Additionally, the key parameters of active support systems under varying different rockburst gradelevels were explored. The findings indicate the followingthat: (1) Compared to passive support, the active support system can significantly reduces the maximum value of σθ /Rb around the tunnel the maximum stress around the tunnel and suppresses the intensity of rockburst intensityoccurrences. The"energy absorption and release" effect of the active support system is more pronounced, aligning better with the principles of rockburst mitigation; (2) Increasing rockbolt anchor bolt strength and decreasing rockanchor bolt spacing both can improve the performance of the active support systems in mitigating rockburst; (3) For medium and intense rockburst scenarios, enhancing rockbolt anchor bolt strength proves to be more effective and economical than reducing rockbolt anchor bolt spacing.
ZHANG Chengyou1 WANG Bo1 DU Zehao1 GAO Junhan1 TAN Lihao2
.Analysis of the Suitability of Different Anchor Bolt Support Systems for Rockburst Mitigation and Optimization of Anchor Bolt Parameters[J] MODERN TUNNELLING TECHNOLOGY, 2024,V61(6): 64-73
2024, Vol. 61 