对不同岩桥长度的双圆孔洞凝灰岩进行单轴压缩试验及声发射测试，获取岩石变形破坏过程的声发射参数，研究岩桥长度对声发射响应特征的影响，并基于声发射特征参数分析预警前兆信息。结果表明：声发射参数随时间呈阶段性变化特征，岩石失稳破坏前有明显异常响应特征；AE能量随岩桥长度增大由群震型向孤震型转变，AE振铃计数经历了平静期、活跃期和突增区，AE RA/AF值对局部细小裂纹扩展较敏感，AE b值随时间经历了上升期、波动期及下降期，总体呈减小趋势；声发射各参数均存在岩石破坏前兆，将AE累计能量、AE累计振铃计数、AE累计RA/AF值突增点和AE b值的最低点作为“临界破坏前兆点”D，预警时效序列为：AE累计RA/AF值＞AE累计振铃计数＞AE累计能量＞AE b值。

Uniaxial compression test and acoustic emission test were carried out on tuff with double round holes of different rock bridge lengths to obtain the acoustic emission parameters of rock deformation and failure process. The influence of rock bridge length on acoustic emission response characteristics was studied, and the early warning precursor information was analyzed based on acoustic emission characteristic parameters. The results show that the acoustic emission parameters change periodically with time, and there are obvious abnormal response characteristics before rock failure. AE energy changes from group earthquake type to solitary earthquake type with the increase of rock bridge length. AE ringing count has experienced quiet period, active period and sudden increase area. AE RA/AF value is sensitive to local small crack propagation. AE b value has experienced rising period, fluctuation period and falling period with time, and the overall trend is decreasing. Each parameter of AE has the precursor of rock failure. The AE cumulative energy, AE cumulative ring count, AE cumulative RA/AF value sudden increase point and the lowest point of AE b value are taken as the’ critical failure precursor point’ D. The early warning time series is: AE cumulative RA/AF value > AE cumulative ring count > AE cumulative energy > AE b value.

国家自然科学基金(52178393)；陕西省创新能力支撑计划-创新团队(2020TD-005)