矿井断裂构造分形特征及其对冲击地压影响的研究

Fractal characteristics of mine fracture structures and their impact on rockburst

  • 摘要: 矿井断裂构造是诱发冲击地压的重要地质因素。为研究断裂构造对冲击地压的影响,以峻德井田为工程研究背景,采用地质动力区划法,将井田内的断裂构造按照不同长度等级划分为Ⅰ−Ⅴ级断块,利用分形理论中的盒维法计算了Ⅴ级断块分形维数,分析了断裂整体分形特征和断裂分区分形特征,探究了断裂构造分形维数与构造应力分布状态、冲击地压之间的耦合关系。结果表明:① 断裂整体分形维数与北西向断裂分形维数具有良好的一致性,北西向断裂对峻德井田冲击地压控制作用的程度较高,北东向断裂次之。② 不同走向断裂的分形维数不同,表明不同走向断裂在空间展布上表现出明显的差异性,反映了分形维数与断裂构造复杂程度呈正相关,即分形维数越大,断裂构造空间分布特征越复杂,越容易诱发冲击地压。③ 区域内的构造复杂程度越高,构造应力集中程度越高,煤层冲击地压主要发生在高应力区,表明构造复杂程度与构造应力集中程度一致性较高。研究成果从分形维数角度对断裂构造进行定量分析,为冲击地压危险性预测及防治提供了新思路。

     

    Abstract: Fracture structures in mines are critical geological factors in triggering rockbursts. This study investigated the impact of fracture structures on rockburst, focusing on the Junde mining area. Using geological dynamic zoning, the fracture structures in the mining area were classified into grade Ⅰ-Ⅴ fracture blocks based on length. The box-counting method in fractal theory was employed to calculate the fractal dimension of grade Ⅴ fracture blocks. The study analyzed the overall and partitioned fractal characteristics of the fractures and explored the coupling relationship between the fractal dimension of fracture structures, structural stress distribution, and rockburst. The results showed: ① The overall fractal dimension of the fractures was highly consistent with the fractal dimension of the NW-trending fractures, indicating that NW-trending fractures had a more significant influence on rockburst in the Junde mining area than NE-trending fractures. ② The fractal dimensions varied among fractures of different orientations, demonstrating clear spatial distribution differences and a positive correlation between fractal dimension and fracture complexity. This implied that a greater fractal dimension corresponded to a more complex spatial distribution of fracture structures, thereby increasing the likelihood of rockbursts. ③ Higher structural complexity was associated with higher stress concentration, and rockbursts in coal seams primarily occurred in high-stress regions, showing a high level of consistency between structural complexity and stress concentration. This study provides a new perspective for predicting and mitigating rockburst risks by quantitatively analyzing fracture structures through fractal dimensions.

     

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