以隧洞围岩的时效变形诱发滞后型岩爆为核心,围绕隧洞围岩的时效变形特性进行声发射辅助岩石三轴蠕变实验和现场微破裂监测实践.研究隧洞围岩在蠕变过程中的微破裂前兆及其时空演化规律,根据卸荷蠕变变形损伤演化规律及蠕变率随时间的发展阶段特征,构建高应力作用下岩体蠕变损伤模型.建立微震活动信息与物理、力学参数变化之间的联系,应用大规模数值分析方法进行不同偏应力作用下隧洞围岩的流变失稳研究.结果表明:深埋岩体隧洞中,岩爆的时间、空间、强度等分布存在较明显的规律性,岩爆发生之前普遍存在一个孕育过程,并伴随着大量微破裂的产生和微震能量的释放(微震前兆),微震活动对岩爆事件普遍具有时间优先性和空间一致性,可利用其指导安全施工,从而为滞后型岩爆预测和安全施工提供新的研究思路.
In recent years,more and more long,large and deeply buried tunnels were constructed and have brought about many deep rock mechanics problems.The prominent rockburst has become a technical bottleneck in the future deep underground engineering.In this paper,the problem that time-dependent deformation of the surrounding rockmass leads to delayed rockburst in deep tunnel is considered as the time-dependent deformation characteristics of the surrounding rockmass in deep buried tunnels.Multi-disciplinary methods such as rheological mechanics,damage mechanics and information science,and performing triaxial creep and AE testing and field microseismic monitoring are adopted to study the crack precursor and its temporal and spatial evolution during rock creep,to analyze creep deformation,associated damage evolution and creep rate evolution characteristics during unloading of deep rock mass,to establish a high-stressed creep damage model,to construct a link between the microseismic events and physicomechanical parameters,to perform a series of numerical simulations on the rheological instability of surrounding rockmass in deep buried tunnels under different partial stresses.The results of study show that there exist laws of temporal,spatial and intensity distribution of rockburst.There is always a process of gestation before rockburst,it is with a lot of micro-fractures emerging and microseismic energy losing (microseismic indication).Microseismic activities always occur ahead of rockburst,while the locations of them coincide with rockburst,thus the safety of construction can be guaranteed.A new idea on prediction of time-dependent rockburst and safe construction is obtained.