Numerical Investigation of Factors Influencing Multiple Hydraulic Fracture Propagation from Directional Long Boreholes in Coal Seam Roofs

作者：Maolin Yang, Shuai Lv, Yu Meng, Xing Wang, Sicheng Wang, Jiang‐fu He · 发表于：Applied Sciences · 年份：2025 · DOI：10.3390/app15126521 · 被引用次数：4 · 研究领域：Rock Mechanics and Modeling、Landslides and related hazards、Geotechnical Engineering and Underground Structures

The hanging of hard roofs in coal seams poses a significant threat to the safe mining of coal. Hydraulic fracturing is an important method to achieve the pre-weakening of coal seam roofs. Clarifying the scope of hydraulic fracturing in coal seam roofs and its influencing factors is a prerequisite for ensuring the effectiveness of the pre-weakening process. In this paper, we developed a fluid–structure coupling numerical simulation model for hydraulic fracturing based on the element damage theory, and have systematically examined the effects of both engineering parameters and geological factors on the hydraulic fracture propagation behavior of the segmented fracturing of coal seam roofs. Results indicate that increasing the injection rate can significantly enhance fracture propagation length. A larger stress difference directs fractures along the maximum principal stress direction and effectively extends their length. Additionally, increasing the spacing between fracture stages reduces stress interference between clusters, leading to a transition from asymmetric to uniform fracture propagation. To validate the numerical simulation results, we conducted a field test on the hydraulic fracturing of the coal seam roof, and monitored the affected area by using transient electromagnetic and microseismic monitoring techniques. Monitoring results indicated that the effective impact range of field hydraulic fracturing was consistent with the numerical simulation results. Through the sy...