深井开采岩石孔洞群能量演化及应力调控方法研究

Deep mining is a process of stress redistribution and energy evolution of surrounding rock, induced by excavation under high stress environment. The concentrated surrounding rock stress accompanied by increased energy storage will cause frequent deep disasters such as rock burst, large deformation and so on. In contrast, release of stress is beneficial to the stability of surrounding rock and disaster prevention. This project aims at studying the energy evolution and the stress regulation of the surrounding rock, which is of great significance to the safety and efficiency of deep mining. Based on the theory of energy principle, stress wave and acoustic emission, by true triaxial test, static-dynamic coupled impact test and similar simulation experiment, this project plans to study the strain characteristics of surrounding rock, acoustic emission rate, energy release rate and spatial correlation length under loading and unloading, to study the correlativity between the incident energy, the reflection energy, the transmission energy, the energy density and the strain rate, the load as well as its rate under different stress paths, and to study the effect of hole excavation location, shape, size, time sequence on stress field and energy field of surrounding rock. Finally, it can obtain the distribution characteristics of mining-induced stress, the failure mechanism of surrounding rock and the law of energy dissipation, fully reveal the unconventional failure mechanism of deep rock mass and develop the strain energy density failure criterion of rock and the regulation methods of high stress near stope area. In conclusion, rock burst and other disasters can be eliminated through pressure release and orderly energy regulation, providing a theoretical basis for the innovation of methods and process of deep mining.

深井开采是高应力环境下孔洞群开挖诱发围岩应力重分布和能量演化的过程，围岩应力集中伴随储能增大导致岩爆、大变形等深部灾害频繁高发，而卸荷则有益于围岩稳定性控制和灾变防治，研究采动诱发围岩能量演化及应力调控对深部安全高效开采意义重大。项目以能量原理、应力波理论和声发射信号处理技术为基础，基于真三轴实验、动静组合冲击试验和相似模拟实验等手段，通过研究加卸载作用下孔洞岩石应变、声发射率、能量释放率和空间相关长度指标特征，研究不同应力路径下入射能、反射能、透射能及能耗密度与应变率、载荷和加卸载速率的相关关系，探讨孔洞开挖位置、形状、尺寸及时序对应力场与能量场的影响效应，获得采动应力重分布特征、围岩失稳破裂机理和耗能规律，充分揭示深部岩石非常规破坏作用机制，构建岩石应变能密度破坏准则和近场区域高应力调控方法体系。通过深部资源卸压开采和能量有序调控来消除岩爆等灾害，为深部采矿方法与工艺变革提供理论基础。

随着地球浅部资源的日益枯竭，地下矿山陆续进入千米级采深阶段，且深部开采已成为当前矿业开发的常态。深部岩体处于“三高一扰动”（高应力、高渗透压、高地温和强开采扰动）的条件，受深部复杂力学环境特征影响，深井开采中冒顶片帮和岩爆等灾害频繁高发，且难以预测和有效控制，矿山安全生产面临严峻挑战。本质上，应力是引起岩体变形和破坏的根本作用力，岩石破裂失稳正是高应力驱动下裂纹萌生、扩展和相互贯通形成宏观断裂的渐进过程。另外，岩石在灾变过程中始终伴随着能量的变化，能量耗散致使围岩产生损伤，能量释放决定围岩破坏的剧烈程度。显然，研究深井开采岩石孔洞群能量演化及应力调控方法尤为必要，是进行深部矿山灾害防控的重要理论基础。本项目综合运用实验室试验、理论分析和数值模拟等相结合的方法进行了系统而又深入的研究，首先，对深部典型硬岩的细观结构和宏观基本力学特性进行了试验研究，获得了了硬岩常见的物理力学参数。其次，将复合形优化方法用于孔洞映射函数的求解并编写了相应的求解程序，由此采用复变函数理论推导了任意应力状态下圆形、直墙拱形、梯形、矩形和方形孔洞周边应力的弹性解析解，并与数值模拟结果进行了补充验证，揭示了深部井巷采动应力场的时效特征和空间分布规律。再次，采用各种岩石力学实验机和分离式霍普金森压杆系统针对含不同孔洞形状、数量、排列组合的硬岩试样开展单轴、双轴和动载等不同加载方式下的力学实验，采用先进的数字图像相关设备和声发射装置监测裂纹扩展过程，获得了高应力下孔洞围岩的破裂演化规律和能量演化过程。最后，借助大型相似模拟实验掌握了深井开采岩石孔洞群力学响应，提出了转移降阶-稳态释放-高效阻断的近场应力调控方法。研究成果为深部开采岩石灾害防控和地压灾害监测提供理论指导和技术支撑。项目共发表了论文42篇（SCI34篇，EI8篇），授权发明专利15项（转化1项）；培养博士、硕士生18名，获省部级奖励3项。