Investigation on instability mechanism and control of abandoned roadways in coal pillars recovery face: A case study

IF 8.2 1区 工程技术 Q1 ENGINEERING, CIVIL
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Abstract

The abandoned roadways (ARs) in front of the longwall face catastrophic instability will seriously hamper mining progress, which is a complicated process related to the stress environment, the roadway section, and the mechanical properties of the surrounding rock. The cusp catastrophe theory is employed to establish a state identification model for the irregular coal pillar-roof system (CPRS) formed by the ARs and re-mining entries. To begin, the state discrimination equation (Δp) for the gradual CPRS is derived, and the critical value at which the system transitions into an unstable state under quasi-static conditions is determined. The results indicated that when 16.49 m ≤ L ≤ 22.63 m (L denotes the equivalent span of the intersection roof) and 0 < Re ≤ 2.61 m (Re denotes the width of the elastic zone within the triangular coal pillar), the triangular CPRS is inherently unstable. Similarly, for trapezoidal CPRS configurations where the length Lm (the span of the right-angled trapezoid roof in the propulsion direction) varies from 4.0 to 12.60 m, the system is unstable as well. Subsequently, the model was further enhanced by accounting for the impact of the Pc (advance stress increment load), where a critical criterion for the catastrophic instability of the CPRS was proposed, which represented the external energy required to transition the CPRS from an unstable state to catastrophic instability in different mining stages. After that, the stability degree of the irregular coal pillar was categorized, and a coupling zoning control technology was applied to CPR operations. Field monitoring results demonstrated the effectiveness of the zoning control technology, providing valuable guidance for similar mining practices.
煤柱回采工作面废弃巷道失稳机理及控制研究:案例研究
长壁工作面前的废弃巷道(ARs)灾难性失稳将严重阻碍开采进度,这是一个与应力环境、巷道断面和围岩力学特性有关的复杂过程。本文采用顶板灾害理论,建立了由AR和回采入口形成的不规则煤柱-顶板系统(CPRS)的状态识别模型。首先,推导了渐变煤柱顶板系统的状态辨识方程(Δp),并确定了准静态条件下系统过渡到不稳定状态的临界值。结果表明,当 16.49 m ≤ L ≤ 22.63 m(L 表示交叉顶板的等效跨度)和 0 < Re ≤ 2.61 m(Re 表示三角形煤柱内弹性区的宽度)时,三角形 CPRS 固有不稳定。同样,梯形 CPRS 配置的长度 Lm(直角梯形顶板在推进方向上的跨度)从 4.0 米到 12.60 米不等,系统也不稳定。随后,通过考虑 Pc(超前应力增量载荷)的影响,对模型进行了进一步改进,提出了 CPRS 灾难性失稳的临界标准,即在不同开采阶段 CPRS 从不稳定性状态过渡到灾难性失稳所需的外部能量。随后,对不规则煤柱的稳定程度进行了分类,并将耦合分区控制技术应用于 CPR 作业。现场监测结果证明了分区控制技术的有效性,为类似的采矿实践提供了宝贵的指导。
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来源期刊
Underground Space
Underground Space ENGINEERING, CIVIL-
CiteScore
10.20
自引率
14.10%
发文量
71
审稿时长
63 days
期刊介绍: Underground Space is an open access international journal without article processing charges (APC) committed to serving as a scientific forum for researchers and practitioners in the field of underground engineering. The journal welcomes manuscripts that deal with original theories, methods, technologies, and important applications throughout the life-cycle of underground projects, including planning, design, operation and maintenance, disaster prevention, and demolition. The journal is particularly interested in manuscripts related to the latest development of smart underground engineering from the perspectives of resilience, resources saving, environmental friendliness, humanity, and artificial intelligence. The manuscripts are expected to have significant innovation and potential impact in the field of underground engineering, and should have clear association with or application in underground projects.
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