Dynamic caving interval technology and its mechanisms for improving top coal recovery at the upward–downward transition of longwall top coal caving panel

IF 2.8 3区工程技术 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS

Computational Particle Mechanics Pub Date : 2025-01-07 DOI:10.1007/s40571-024-00895-9

Weijie Wei, Dongliang Cheng, Jinwang Zhang, Guanghui Fu, Huashun Xie, Yipeng Zhang, Xiujuan Li, Yaochen Wang

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引用次数: 0

Abstract

The longwall top coal caving mining (LTCC) is one of the effective mining methods for thick coal seams in China. With the advancement of LTCC panel, upward mining, downward mining and alternate upward–downward mining always occur in the whole mining process, which has great effect on the top coal drawing law. By summarizing the motion characteristics of top coal and gangue in upward mining or downward mining, the dynamic caving interval technology for the upward–downward transition is proposed in this paper, and the variation of top coal boundary, caving body and top coal recovery at different caving stages in this technology is analyzed by discrete element numerical simulation. The results show that when the LTCC panel adopts the dynamic caving interval technology, the top coal boundary is relatively smooth and the caving body develops preferentially in vertical direction at the upward mining stage with the interval of one-cutting and one-caving. When the interval of three-cutting and one-caving is used at the downward mining stage, the intrusion of gangue can be effectively reduced toward the goaf, and the horizontal development of caving body is obvious. Compared with the conventional fixed caving interval technology, the top coal recovery of the whole panel under the dynamic caving interval technology is improved by about 3.64%. In the excessive caving process, the terminated gangue mixed ratio at downward mining stage and horizontal mining stage is low under the same high top coal recovery, at 10–15%. The research results provide a new approach for improving the top coal recovery at the upward–downward transition stage and obtain a theoretical basis for determining the closing time of caving opening in intelligent LTCC.

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长壁放顶板上下过渡时动态放顶段技术及其提高顶煤采收率的机理

长壁放顶煤开采是中国厚煤层开采的有效方法之一。随着LTCC盘面的推进，在整个开采过程中不断发生上采、下采和上下交替开采，对顶板放煤规律产生了较大影响。在总结顶煤和矸石在上采和下采过程中的运动特征的基础上，提出了上下过渡的动态放顶段技术，并通过离散元数值模拟分析了该技术不同放顶段阶段顶煤边界、放顶体和顶煤回采量的变化规律。结果表明：当LTCC盘采用动态放顶段技术时，在上采阶段，以一切一放的间隔，顶煤边界相对光滑，放顶体优先向垂直方向发育；下采阶段采用三切一放间隔，可有效减少矸石向采空区的侵入，垮落体水平发育明显。与常规固定放煤间隔技术相比，动态放煤间隔技术下全盘顶煤采收率提高约3.64%。在过量崩落过程中，在相同高顶煤采收率条件下，下采阶段和水平采阶段终止矸混合比较低，为10 ~ 15%。研究结果为提高上下过渡阶段顶煤采收率提供了新途径，为智能LTCC放顶煤开孔闭合时间的确定提供了理论依据。

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来源期刊

Computational Particle Mechanics Mathematics-Computational Mathematics

CiteScore

5.70

自引率

9.10%

发文量

期刊介绍： GENERAL OBJECTIVES: Computational Particle Mechanics (CPM) is a quarterly journal with the goal of publishing full-length original articles addressing the modeling and simulation of systems involving particles and particle methods. The goal is to enhance communication among researchers in the applied sciences who use "particles'''' in one form or another in their research. SPECIFIC OBJECTIVES: Particle-based materials and numerical methods have become wide-spread in the natural and applied sciences, engineering, biology. The term "particle methods/mechanics'''' has now come to imply several different things to researchers in the 21st century, including: (a) Particles as a physical unit in granular media, particulate ﬂows, plasmas, swarms, etc., (b) Particles representing material phases in continua at the meso-, micro-and nano-scale and (c) Particles as a discretization unit in continua and discontinua in numerical methods such as Discrete Element Methods (DEM), Particle Finite Element Methods (PFEM), Molecular Dynamics (MD), and Smoothed Particle Hydrodynamics (SPH), to name a few.