基于双重能量约束的煤与瓦斯突出发展及强度分析理论

A theoretical framework for development and intensity analysis of coal and gas outburst based on dual energy constraints

  • 摘要: 基于“源−耗”关系的能量守恒模型长期主导煤与瓦斯突出的定量化研究,但单式约束在描述具体能量演化路径时存在局限性,注定其研究方法以对比分析为主,难以反映煤与瓦斯突出的动态发展过程。通过揭示突出激发阶段煤体变形能预释放与瓦斯膨胀能释放的协同作用机制,构建包含全过程能量判据的新型理论框架。首先,基于煤体拉伸破坏的临界应力−孔隙率耦合关系,推导瓦斯膨胀能阈值的解析表达式,并建立考虑工作面应力和瓦斯非均匀分布特征的突出激发能量判据;然后,将传统的能量守恒式作为突出发展的判别式,建立基于变形等效原理的突出不同阶段煤体搬运功计算模型、基于最小新增面积原理的煤体破碎功计算模型,以完善突出发展的多阶能量约束体系;最后,提出能量链式释放理论,通过“激发—发展”双条件时序约束机制,多阶段动态模拟突出过程。结果表明:随着与工作面距离的增加,煤层储能与突出阈值呈现非线性递增趋势,且突出阈值的超线性增长特性导致二者形成自下而上的交叉点,该临界交点决定了煤体抛出的空间范围;突出初始阶段受激发条件主导,后期转为发展条件控制;经参数敏感性分析,确定能量转化效率为30.5%~66.1% (μ=52.3%±13.1%),该参数使模拟结果与近年来事故案例突出强度数据吻合度较好。研究发现,构造煤(f < 0.2)在高地应力( > 35 MPa)和低瓦斯压力( < 0.52 MPa)条件下仍具备突出潜能,建议将地应力监测提升为煤矿动力灾害防控的核心指标。本研究建立的“激发—发展”全周期能量链式分析体系,为突破难以定量化表征突出过程的瓶颈提供了新范式。

     

    Abstract: The “source-sink” energy conservation model has long underpinned quantitative coal and gas outburst research, yet its oversimplified constraints limit precise energy pathway characterization, relegating analyses to semi-quantitative comparisons. This study addresses two essential processes for outburst initiation: the pre-release of coal deformation energy and the induced elevation of gas expansion energy release. Building on this foundation, we propose a gas expansion energy threshold formula derived from critical tensile failure stress and porosity conditions, and establish discriminant criteria for outburst-triggering energy that integrate working face stress distribution and gas spatial heterogeneity. Both coal seam energy and outburst thresholds exhibit nonlinear increases with distance from the working face. Notably, the threshold variation demonstrates higher-order mathematical characteristics, intersecting the energy profile from below to determine coal ejection zones. By adopting the energy conservation equation as a discriminant criterion, two computational models are developed: a coal transport work model for distinct outburst stages based on the deformation equivalence principle, and a coal fragmentation work model grounded in the minimum incremental area principle. These advances collectively refine energy constraints governing outburst progression. Under the hypothesis of chain-reaction development, an energy chain-release analysis method constrained by temporally sequential energy criteria is proposed. Numerical simulations reveal that when energy distribution ahead of the working face simultaneously satisfies initiation and propagation constraints, the system enters cyclical outburst phases. Outburst evolution transitions from initiation-dominated constraints in early stages to propagation-dominated constraints in later phases. Calibrating energy conversion efficiency (30.5%-66.1%, mean 52.3%±13.1%) aligns simulated intensities with recorded outburst intensity data from actual accidents. Crucially, tectonically deformed coal (f < 0.2) exhibits outburst potential even under low gas pressure ( < 0.52 MPa) combined with high in situ stress ( > 35 MPa), underscoring geomechanical stress as a prioritized prevention indicator. This study establishes a unified theoretical framework bridging energy quantification and outburst dynamics, advancing mechanistic understanding through multi-constraint energy-chain modeling.

     

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