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    遗煤资源绿色开采与采空区功能提升中的煤岩动态力学问题研究与探讨

    Research and discussion on dynamic mechanics of surrounding rock in green mining of residual coal resources and function improvement of goaf

    • 摘要: 遗煤资源储量丰富、赋存广泛,兼具优质能源与战略空间双重价值。基于遗煤资源绿色开采和采空区功能提升中的扰动应力波来源、传播衰减和静态荷载特征,提出了“低频扰动+静态预应力”耦合的煤岩动态力学响应科学问题,构建了针对“遗煤开采−空间开发”协同体系的低频扰动岩体力学理论架构,搭建了“水−气−温”多场动静载耦合试验系统。结合现有研究,系统开展了扰动荷载作用下煤岩“拉−压−剪”动态力学响应特征研究,量化了高应力煤岩失稳前扰动荷载循环周期数和幅值之间的关系,得到了扰动荷载作用下不同静态预应力水平砂岩、煤、充填体的强度劣化特性,提出了低频扰动下高应力煤岩失稳的超前预测判据,揭示了煤岩强度劣化和微观裂纹演化之间的内在关联机制,推导了考虑低频扰动效应的损伤变量和强度准则。研究表明,在遗煤开采可行性分析、稳定性评价和围岩动态失稳防控中需要充分考虑采掘扰动的影响。相关研究成果可以为遗煤资源开采和采空区功能提升提供科学指导与决策依据。受采空区积水、瓦斯积聚、冲击矿压和火区扩展等多元风险因素的威胁,遗煤安全绿色开采及采空区功能提升仍面临挑战。扰动岩体力学理论在“遗煤开采−采空区功能提升”协同体系的工程应用中,尚需突破以下技术瓶颈:“水−气−温”复杂环境下的煤岩扰动力学响应特征尚不明确;多重采动影响下残采区围岩裂隙对扰动损伤的放大效应缺乏定量表征;扰动影响下储碳/负碳新型充填体及其构筑空间的稳定运维亟待研究;沉积岩的岩性复杂,动态力学普适性规律揭示和通用本构模型构建面临挑战。需要在煤矿安全规范框架下,推动扰动岩体力学理论在遗煤开采工程中的应用,力求实现遗煤资源绿色低碳开发与采空区赋能应用技术的突破,助力遗留难采煤炭资源安全绿色高采出率开采关键技术的发展和推广。

       

      Abstract: Residual coal resources are abundant and widely distributed, possessing dual value as high-quality energy and strategic underground space. Based on the origins, propagation attenuation, and characteristics of static loading associated with disturbance stress waves during upward mining and underground space utilization in coal mine goafs, this study proposes the scientific issue of “low-frequency dynamic disturbance coupled with static pre-stress.” A theoretical framework of disturbed rock mechanics was developed to support the synergistic system of residual coal recovery and underground space development. A multi-field coupling servo testing system was independently designed, capable of applying water–gas–temperature conditions along with static and dynamic loads. Drawing on prior studies, this research systematically investigates the dynamic mechanical responses of coal and rock materials under low-frequency disturbances, including tension, compression, and shear behaviors. The relationship between the number of disturbance cycles and amplitude prior to instability in high-stress coal and rock was quantitatively characterized. Strength degradation behaviors under various static pre-stress levels were evaluated for sandstone, coal, and backfill materials. Predictive criteria were proposed for the pre-failure identification of high-stress coal–rock systems under disturbance, revealing intrinsic mechanisms linking strength degradation to microcrack evolution. A damage variable and strength criterion incorporating low-frequency disturbance effects were derived. Findings indicate that the influence of excavation-induced disturbance must be fully considered in feasibility assessments, stability evaluations, and dynamic instability prevention during residual coal mining. These results provide theoretical guidance and decision support for the safe and efficient development of residual coal and underground resources in mined-out areas. However, challenges remain in achieving safe and green recovery of residual coal and the scientific utilization of goaf spaces, particularly under the compounded risks of water accumulation, gas buildup, dynamic pressure, and spontaneous combustion. The practical application of disturbed rock mechanics in the “residual coal–space development” framework still faces several technical bottlenecks: The dynamic mechanical behavior of coal and rock under complex water–gas–thermal conditions remains unclear; The amplification effect of existing fractures in disturbed coal–rock mass under multiple mining disturbances lacks quantitative characterization; The stability and long-term operation of novel carbon storage/fixing backfill materials and their constructed spaces require further study; The lithological heterogeneity of sedimentary rocks hinders the development of universal dynamic mechanical models and constitutive relationships. To overcome these challenges, it is essential to advance the engineering translation of disturbed rock mechanics theory within the regulatory framework of coal mine safety. This will enable breakthroughs in green, low-carbon utilization of residual coal resources and the empowered transformation of goaf space, supporting the development and implementation of critical technologies for high-recovery, safe, and sustainable mining of difficult-to-extract coal resources.

       

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