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深部原生煤岩组合体三轴压缩破裂特征与失稳模式

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  • 国家科技期刊平台
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[目的]深部含煤地层原生分界面及其层状组合结构发育,在开采扰动作用下,层状煤岩体的原生组合结构破裂失稳是诱发突水等灾害的主要原因之一.[方法]为研究深部开采原生煤岩组合结构对层状岩体稳定性的影响,室内开展三轴压缩破裂试验及CT扫描重构,获得深部原生煤岩组合体与煤、岩单体破裂的差异,分析深部原生煤岩组合体分界面及其胶结区域的强度变化规律,划分其三轴压缩失稳的主导模式为低强度煤、原生胶结面及高强度岩石失稳 3种,揭示各主导模式形成的力学机制,明确煤岩组合体失稳强度介于低强度煤与高强度岩石之间的力学机理.[结果和结论]结果表明:深部原生煤-岩及煤-岩-煤组合体的失稳强度介于煤、岩单体之间,前两者大小与其岩石含量及界面结构相关;原生界面区域煤的抗压强度变化速率对泊松比、黏聚力与内摩擦角等参数变化敏感,并远高于岩石;低强度煤的主破裂可穿越原生分界面,促使硬岩产生类似于含单裂隙结构面岩石的破裂机制,并导致组合体的失稳强度低于岩石单体.研究成果提升了对深部开采层状岩体失稳致灾机理的认识.
Fracturing characteristics and instability modes of deep primary coal-rock combinations under triaxial compression
[Objective]Deep coal-bearing strata contain primary interfaces and layered composite structures.Under the mining disturbance,the fracturing and instability of the primary composite structures of layered coal-rock combinations prove to be a principal cause of disasters such as water inrushes.[Methods]This study aims to explore the impacts of the structures of deep primary coal-rock combinations on the stability of layered rock masses during coal mining.Using fracturing tests under triaxial compression and CT-based reconstruction conducted in the laboratory,this study determ-ined the fracturing differences between deep primary coal-rock combinations and single coal or rock masses.Based on the analyses of the laws of changes in the strength of the interface and cementation areas of deep primary coal-rock com-binations,this study identified three dominant instability modes under triaxial compression:instability of low-strength coals,primary cementation interfaces,and high-strength rocks.By revealing the mechanical mechanisms underlying the three instability modes,this study determined that the instability strengths of coal-rock combinations fall between those of low-strength coals and high-strength rocks.[Results and Conclusions]Key findings are as follows:(1)The instabil-ity strengths of deep primary coal-rock and coal-rock-coal masses,associated with the rock content and interface struc-tures,fall between those of coal and rock masses.(2)The changing rate of the compressive strength of coals at the primary interface is sensitive to Poisson's ratio,cohesion,and internal friction angle,far exceeding that of rocks.(3)The main fracturing of low-strength coals can penetrate the primary interface,causing the fracturing mechanism of hard rocks to resemble that of rocks with single-fracture structural planes and rendering the instability strength of coal-rock combinations lower than that of rocks.The findings of this study gain a deeper understanding of the mechanism behind disasters caused by instability dueing the mining of deep-layered rock masses.

deep miningprimary coal-rock combinationfracturing under triaxial compressioninstability modecoal-rock interface

李春元

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煤炭科学研究总院有限公司 深部开采与冲击地压防治研究院,北京 100013

天地科技股份有限公司北京技术研究分公司,北京 100013

深部开采 原生煤岩组合体 三轴压缩破裂 失稳模式 煤岩分界面

国家自然科学基金项目中国煤炭科工集团有限公司科技创新创业资金专项重点项目煤炭科学研究总院创新创业科技专项资助项目

519043032022-3-ZD0012021-KXYJ-004

2024

10.12363/issn.1001-1986.24.01.0013

煤田地质与勘探
中煤科工集团西安研究院

煤田地质与勘探

CSTPCD北大核心
影响因子：1.079
ISSN：1001-1986
年,卷(期)：2024.52(8)
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