Dong Longjun, Zhang Yihan, Chen Zhongjie, Kou Yongyuan, Pei Zhongwei
The School of Resources and Safety Engineering, Central South University, Changsha, 410083, China.
Jinchuan No.2 Mine, Jinchuan Group Co., LTD., Jinchang, 737100, China.
Sci Rep. 2024 Jul 17;14(1):16499. doi: 10.1038/s41598-024-66445-8.
The quantitative characterization of rock mass and stress changes induced by mining activities is crucial for structural stability monitoring and disaster early warning. This paper investigates the time-space-intensity distribution of microseismic sources during the pillar-free large-area continuous extraction. Furthermore, it explores a method involving collaborative evolution patterns of the velocity field and spatial b-value to identify stress and structural changes at the panel stope. Results show that anomalous zones in wave velocities and b-values form at the intersections of extraction drifts, strike drifts, cross drifts, and connection roadways influenced by mining activities, as well as in footwall ore-rock contacts, often accompanied by the nucleation of microseismic events. The synergistic use of wave velocity fields and spatial b-value models reveals the relationship between stress migration behavior and stope structure changes due to mining disturbances. The velocity field primarily reflects macroscopic changes in the structure and stress distribution, while spatial b-values further explain stress gradients in specific areas. Additionally, we have advanced the identification of an instability disaster at the connection roadway and cross drift intersection based on increases in wave velocity and abnormal changes in b-value. This paper demonstrates the potential of risk identification using the proposed method, providing insights into predicting geotechnical engineering disasters in complex stress environments.
岩体定量表征以及采矿活动引起的应力变化对于结构稳定性监测和灾害预警至关重要。本文研究了无矿柱大面积连续开采过程中微震源的时空强度分布。此外，还探索了一种涉及速度场和空间b值协同演化模式的方法，以识别盘区采场的应力和结构变化。结果表明，受采矿活动影响的回采巷道、走向巷道、穿脉巷道和联络巷道的交叉点以及下盘矿岩接触带会形成波速和b值异常区，且常伴有微震事件的成核。波速场和空间b值模型的协同使用揭示了采矿扰动引起的应力迁移行为与采场结构变化之间的关系。速度场主要反映结构和应力分布的宏观变化，而空间b值则进一步解释特定区域的应力梯度。此外，基于波速增加和b值异常变化，我们改进了对联络巷道和穿脉巷道交叉点失稳灾害的识别。本文证明了使用所提出方法进行风险识别的潜力，为预测复杂应力环境下的岩土工程灾害提供了见解。
