动态扰动触发深部岩体失稳破裂的时间滞后效应研究

During deep underground mining, the rockburst that may be triggered by dynamic disturbance usually lags behind the blasting operation, which brings great difficulties for predicting the occurrence time of rockburst. This project aims to investigating the time-dependency of the unstable failure of high-stress rockmass that is triggered by dynamic disturbances such as rock blasting. Firstly, the creep test of rock, which may be altered by the dynamic disturbance, is carried out in order to examine the damage behavior of rock under creep conditions that may be affected by the dynamic disturbance. Secondly, considering the rock damage as the main thread, a damage-based model is developed to represent the tertiary creeps of rock triggered by dynamic disturbance, based on which, a numerical program is developed. Thirdly, by employing the blasting-induced vibration monitoring and microseismic monitoring, the response of surrounding rockmass of deep underground excavation to the blasting is measured, in order to examine the deformation and damage characteristics of surrounding rockmass that is related to blasting, based on which, the excavation- and blasting-induced damage of surrounding rockmass are characterized. Lastly, the mechanical model of surrounding rockmass of underground excavation is established and the evolution of damage zone and development of deformation of surrounding rockmass subjected to blasting is numerically simulated. Based on the numerical results and monitoring data, the evolution of damage zone is predicted, in order to clarify the possible precursory features for the unstable failure of rock mass. This study may provide theoretical basis for the prediction of time-lag rockburst triggered by dynamic disturbance.

在深部开采中，爆破等动态扰动诱发矿山岩爆往往滞后于爆破作业，表现出时间滞后效应，这给预报岩爆的发生时间带来了极大的困难。本研究以动态扰动触发深部岩体岩爆具有时间滞后效应的机理为研究目标，首先，进行动态扰动后岩石蠕变损伤的试验，分析动态扰动对岩石流变损伤的影响特征；其次，以岩石的损伤为主线，发展动态扰动影响后岩石发生加速流变的损伤力学模型，并研发数值模拟系统；再次，借助于爆破震动测试和微震监测技术对试验巷道围岩进行实时监测，认识围岩开挖损伤区的时空演化规律，并基于测试数据进行围岩力学参数及损伤变量的数值表征；最后，基于监测数据建立巷道围岩的力学模型，进行爆破应力波作用下围岩损伤及失稳破裂时间效应的数值模拟，把数值模拟和现场监测结果相结合，探讨爆破应力波作用下巷道围岩损伤区的时空演化规律，探寻瞬时岩爆或滞后岩爆发生的条件及前兆特征，为爆破应力波触发深部巷道岩爆的评价提供新的理论依据。

在深部采矿工程中岩爆往往在爆破扰动后滞后一段时间才发生，表现出明显的时间滞后效应，这给岩爆的预报和预警带来了极大的困难。本研究以动态扰动触发深部岩体岩爆具有时间滞后效应的机理为目标，首先，进行了动态扰动下岩石蠕变效应和松弛效应实验，分析了不同初始应力（或应变）、扰动波形以及含水率对于岩石流变及其扰动下的失稳破裂的影响；其次，以岩石的损伤为主线，通过与黏弹性力学理论相结合建立了动态扰动下岩石流变损伤的力学模型，与弹性动力学理论相结合建立了围岩瞬态卸荷及爆破损伤致裂煤层的弹性动力损伤模型，研发了多应变率条件下岩石损伤与破坏的数值模拟程序；开展岩石蠕变-冲击和松弛-冲击条件下的数值模拟，通过将数值模拟结果与实验结果进行对比分析，验证了程序的正确性，继而讨论了动态扰动对岩石流变损伤的影响，研究了不同侧压力系数和不同卸荷条件下围岩应力场的变化规律和损伤区的分布特征；再次，基于损伤力学理论和流固耦合理论建立了脉冲水压致裂的力学模型，结合高压空气爆破致裂过程的试验，反演高压气体加载曲线，将爆破载荷视为爆破应力波和爆生气体压力的依次共同作用，借助于数值模拟分析高压空气爆破损伤区演化过程，分析了致裂的机理及影响因素；同时，进行了现场爆破振动测试，研究了不同爆破条件下振动信号的频带能量分布特征，研发了岩石爆破损伤过程分析系统，分析了不同地应力条件和节理角度双孔爆破和切缝药包爆破爆生裂纹萌生-扩展-贯通过程的演化规律；最后，基于声发射监测数据进行岩体参数及损伤的表征，反分析模型中因破裂引起的物理、力学参数的变化，再现了单轴压缩岩石破裂全过程，分析了基于声发射监测数据进行岩石破坏预测的可行性，并将室内声发射数据的预测方法应用于现场微震监测数据的解读，基于微震活动的时空演化特征，得出了石人沟铁矿矿山境界顶柱断裂前兆现象时序特征，推测出了其隐含断层边界，对其破坏风险做出了评价。