深部硬岩近采区应力的量化表征及调控机制

The project focuses on concentrating laws and releasing process of rockmass stress, where transient and delayed instability occurred near underground stopes induced by deep mining in hard rocks. The laboratory experiments, in-situ tests, numerical simulation, and theoretical analysis will be applied to research the significant problem. Firstly, the objective function and constraints for wave velocity field tomography will be explored by taking the advantage of controllable parameters of active source. Then, the physico mathematical model for wave velocity field tomography near underground stopes will be established with the cooperative functions of active and passive sources. Secondly, the complex spatial structure and stress distribution near underground stopes will be simulated by excavating multiple holes during the similar material tests under bi-directional loading. Using the acoustic emission monitoring system, the active source triggered by hammering and the passive source triggered by loading will be used to verify and optimize the model for wave velocity field tomography. Based on the acoustic emission and microseismic data and the result of wave velocity field tomography, it will be feasible to establish the representation model for quantified stress. In addition, the physico mechanical conditions for transient and delayed instability of rockmass will be explored clearly. Finally, the areas of stress concentration can be identified through the combination of the numerical simulation and in-situ tests in a deep hard rock mine. Furthermore, the precursory characteristics of rockmass instability near underground stopes will be revealed. The mechanical conditions of dedicating the high stress in the potential transient instability areas to beneficial rock fragmentation will be obtained. The adjustment method for weakening the seismic magnitude in the potential delayed stability areas of high stress will be explored. The stress control mechanism for the “disturbance stage, adjusting stage, instability stage” system of rockmass near underground stopes will be clarified. This project is expected to provide theoretical supports for the beneficial utilization of high stress in hard rocks, as well as prevention and control of disasters induced by rockmass instability near underground stopes in deep mining.

针对深部硬岩开采诱发的近采区瞬态与延迟失稳中应力集聚规律与释放过程，通过室内实验、现场试验、数值仿真、理论分析等手段进行研究。首先利用主动震源参数可控性优势，探究波速场成像的目标函数和约束条件，建立近采区协同主被动震源的波速场成像数学物理模型；其次在相似材料双向加载试验时，通过多孔洞开挖模拟近采区复杂空间结构与应力分布，利用声发射监测下锤击产生的主动震源和加载产生的被动震源验证并优化上述波速场成像模型，进而联合声发射与微震震源及波速场成像结果建立应力量化表征模型，探明岩体瞬态与延迟失稳的物理力学条件；最后结合数值模拟与现场试验，辨识应力集聚区，揭示近采区岩体失稳的前兆特征，寻求潜在瞬态失稳区高应力向良性碎岩转化的力学条件，探究延迟失稳高应力区震源震级弱化的调控方法，阐明近采区岩体“扰动期—调整期—失稳期”系统的应力调控机制。本项目将为深部硬岩开采中高应力良性利用及失稳灾害防控提供理论依据。

随着硬岩矿山开采深度的增加，岩体地应力持续增大，采掘爆破等开采扰动使得岩体中应力重新调整和分布，极易诱发大震级微震事件地发生，严重的还会因高应力岩体储能的释放诱发岩体大范围垮塌、岩爆等灾害，造成采矿作业人员伤亡和设备严重破损，使得大量矿石无法采出，严重威胁着深部硬岩安全高效开采。为解决上述难题，本项目主要从深部硬岩开采震源精准定位方法、深部硬岩开采震源机制与岩体响应和深部开采能量调控与灾害防治三个方面开展研究，基于解析定位算法与Logistic概率分布函数提出了一种异常到时识别方法，并据此针对复杂深部采矿环境中异常到时数据和预先测定的波速误差对微震定位的精度影响较大的难题，提出了解析迭代协同定位算法（CLMAI），提高了深部开采区域岩体失稳源的定位精度；发明了一种高应力区隧道围岩区域应力场的二次测试方法用以掌握岩体中应力的分布状态，并基于改进A*算法和潜在异常区域匹配的思想创新性地提出了一种探测异常区域位置及大小的方法，可为异常区域的确定、岩体失稳前兆指标的提取提供指导；基于全波形矩张量反演方法，定量地分析各破坏类型下岩石破裂方向和破裂过程，揭示了不同岩体失稳类型的震源机制，发明了考虑岩体响应的深部岩体工程标准化支护方法，为硬岩开采中不同类型灾源辨识和岩体工程防护提供了技术支撑；建立了微地震荷载影响下的区间非概率可靠度分析模型，能够为硬岩开采过程中岩体工程稳定性评估提供技术指导；最终定量分析了各指标参数在岩石破坏各阶段中的时间关系，对岩石所处损伤状态进行风险划分和识别，揭示了基于声发射技术的岩石破裂前兆特征，提出了花岗岩失稳风险评价方法和判据模型。本项目的研究成果可为深部硬岩回采参数的设计与优化、高应力集聚区域岩体稳定性分析、深部岩体工程支护及危险区域超前辨识等提供重要的理论依据。.基于以上研究成果，在中国工程院院刊Engineering等国内外知名期刊发表标注学术论文17篇（其中，第一标注11篇、第二标注5篇、第三标注1篇），SCI检索14篇，项目负责人以第一或通讯作者发表论文15篇，以第一发明人申请国家发明专利9项，已授权6项，申报省部级奖励6项，湖南省技术发明一等奖等4项已授奖，2项处于评审阶段，主持撰写了行业团体标准1项。