Abstract

To eliminate roof-control disasters typically encountering in mines with thick and hard rock strata, fracture characteristics, instability mechanism and prevention methods were investigated in the study. A mine stope with thick and hard main roof and wedge-structure immediate roof in Zhuxianzhuang Coal Mine was taken as the background. In terms of the strata behaviors and roof control difficulty levels via physical simulations, mining zones were classified into strong pressure behavior zone, less-strong pressure behavior zone and pressure mitigation zone. Theoretical analysis was used to study the interaction characteristics of the support-surrounding rock under different mining zones and the principles and methods of zonal control under THR were proposed. A coordinated control method, which combined confined blasting in water-filled deep holes for reducing the roof fracture size and reasonable support optimization for increasing the supporting intensity, was applied to the strong pressure behavior zone and less-strong pressure behavior zone. The mechanical calculation model of a “presplit-THR-block–immediate-roof-top-block–top-coal-wall–hydraulic-support” system was established, which determined the length of confined blasting blocks as 20–25 m and supporting intensity as 1.15–1.28 MPa. These parameters can satisfy the requirements of THR control and lead to the best economic performance.

Article Highlights

• Study the fracture characteristics and instability migration law of THR, could be found in 3.1 Structural characteristics of the THR in close distance during the first weighting part.

• Divide the mining zones based on the strata behaviors and roof control difficulty, could be found in 3.1 Control zones of THR part.

• The principles and methods of zonal control under THR were proposed, could be found in 3.2 Zonal control principles and methods for THR, 3.3 Mechanical model of pre-control of THR in close distance and determination of working resistance, and the 3.4 Pre-control technology for THR in close distance part.

中文翻译：

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楔形结构直接顶板发生厚硬岩动力破坏与稳定性模型分析

摘要

为消除厚硬岩层矿山常见的顶板控制灾害，研究了断裂特征、失稳机理和防治方法。以朱仙庄煤矿一个厚硬的主顶板和楔形结构直接顶板的采场为背景。通过物理模拟，根据地层行为和顶板控制难度等级，将矿区划分为强压力行为区、弱压力行为区和压力缓释区。通过理论分析研究了不同采区下围岩的相互作用特征，提出了THR下分区控制的原则和方法。一种协调控制方法，将充水深孔密闭爆破减小顶板裂缝尺寸和合理优化支护提高支护强度相结合的方法，应用于强压力行为区和弱压力行为区。建立了“预裂-THR-块-直接-顶-顶-块-顶-煤-壁-水力-支撑”系统的力学计算模型，确定约束爆破块长度为20-25 m，支撑强度为 1.15–1.28 MPa。这些参数可以满足 THR 控制的要求，并带来最佳的经济性能。建立了“预裂-THR-块-直接-顶-顶-块-顶-煤-壁-水力-支撑”系统的力学计算模型，确定约束爆破块长度为20-25 m，支撑强度为 1.15–1.28 MPa。这些参数可以满足 THR 控制的要求，并带来最佳的经济性能。建立了“预裂-THR-块-直接-顶-顶-块-顶-煤-壁-水力-支撑”系统的力学计算模型，确定约束爆破块长度为20-25 m，支撑强度为 1.15–1.28 MPa。这些参数可以满足 THR 控制的要求，并带来最佳的经济性能。

文章亮点

• 研究THR的断裂特征和失稳迁移规律，可以在3.1 THR第一配重部分近距离结构特征中找到。

• 根据地层行为和顶板控制难度划分采区，见THR部分3.1控制区。

• 提出了THR下分区控制的原理和方法，参见3.2 THR分区控制原理和方法，3.3近距离THR预控和工作阻力确定的机械模型，3.4预控技术对于近距离部分的THR。