含断层围岩采动应力场连续演化透明解析方法初探
Preliminary study on transparent analysis of continuous evolution of mining-induced stress fields in surrounding rocks of faulted roadway
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摘要: 开采扰动引起的含断层围岩结构应力场变化是诱发断层型冲击地压的根本原因。直观描述和定量表征含断层围岩采动应力场的连续演化规律, 对于揭示断层型冲击地压致灾机理、实现冲击地压灾害源头治理与防控具有重要意义。采用3D打印技术及应力光敏材料, 制备了含断层围岩结构的高精度透明物理模型, 利用自主研发的矿山巷道围岩采动应力场透明解析实验装置, 获得了煤层开挖过程中含断层围岩结构内部全场应力连续演化过程。通过改进十步相移算法, 克服了传统数字光弹解包裹算法中的误差问题, 量化解析了工作面开采过程引发的围岩结构内部主应力差、切应力演化特征; 揭示了采动过程中巷道围岩结构“卸载拱”演化与低应力区迁移规律以及断层邻域应力响应特征, 刻画了采动影响下断层失稳滑移的敏感区域, 给出了断层滑移的临界条件。研究发现: 当断层达到临界滑移状态时, “卸载拱”与低应力区融合, 卸载区高度扩展至煤层高度6倍左右, 待开采煤层两端主应力差增加至基准状态的2倍以上, 断层面切应力增至初始值的1.3倍左右。研究为准确理解采动诱发断层型冲击地压的机理及影响因素, 实现冲击地压风险的精准研判提供了实验支撑与理论基础。Abstract: The variation of stress fields in faulted surrounding rock structures induced by mining disturbance is the fundamental cause of fault-type rock burst. Visually describing and quantitatively characterizing the continuous evolution of mining-induced stress fields in such structures is crucial for revealing the mechanism of fault-induced rock burst and achieving effective source control and prevention. In this study, high-precision transparent physical models of faulted surrounding rock structures were fabricated using 3D printing technology and stress-sensitive photoelastic materials. A self-developed transparent analysis experimental system for mining-induced stress fields in surrounding rocks of mine roadway was employed to capture the continuous full-field stress evolution within the faulted rock structures during coal seam excavation. By improving the ten-step phase-shifting algorithm, the study overcame the error issues associated with traditional digital photoelastic phase-unwrapping methods. This enabled the quantitative analysis of the evolution characteristics of principal stress difference and shear stress within the surrounding rock structures caused by the advance of the working face. The study further revealed the evolution of the "unloading arch", the migration of low-stress zones during mining, and the stress response characteristics in the vicinity of fault. It also identified sensitive regions prone to fault instability and slip under mining influence and proposed the critical conditions for fault slip.The results show that when the fault reaches a critical slip state, the unloading arch merges with the low-stress zone, causing the unloading zone to expand vertically to approximately six times the coal seam height. Meanwhile, the principal stress difference at both ends of the unmined coal seam increases to more than twice the baseline level, and the shear stress on the fault surface rises to approximately 1.3 times its initial value. This research provides both experimental support and a theoretical foundation for accurately understanding the mechanisms and influencing factors of mining-induced fault-type rock burst, thereby contributing to precise risk assessment and effective hazard control.