深埋薄基岩厚煤层开采评价及岩层-地表控制研究

Evaluation of mining and strata-surface control in deeply buried thick coal seams under thin bedrock

  • 摘要: 为实现深埋薄基岩厚煤层绿色高效开采,以赵固二矿为工程背景,采用理论分析、室内试验和现场实测方法,对比分析分层、大采高和放顶煤开采条件下工艺与装备、技术难题与解决方案和经济效益指标等,构建基于经济-开采技术指标的开采方案适应性评价模型,提出巨厚冲积层地表沉陷预测方法。研究结果表明:放顶煤开采适应性最强,大采高开采次之,分层开采适应性最差;基于覆岩冒落拱失稳特征建立的动载荷法可用于指导液压支架选型;冲积层底部注浆改性加固可提高薄基岩-冲积层界面区域的整体性和隔水性,促进顶板高耸岩梁结构的形成,削弱厚冲积层载荷向工作面支架的集中传递;构建的地表沉陷预测模型揭示地表沉陷系数大于1.0的力学机制。研究为深埋薄基岩厚煤层开采方案选择、岩层控制及沉陷区减损治理提供参考。

     

    Abstract: To achieve green and efficient mining of deeply buried thick coal seams under thin bedrock, this study takes the Zhaogu No.2 Mine as the engineering background and employs theoretical analysis, laboratory experiments, and field measurements. The technologies and equipment, technical difficulties and corresponding solutions, and economic benefit indicators under multi-slicing mining, large-cutting-height mining, and top-coal caving mining are compared. An adaptability evaluation model for mining methods is established based on economic and mining-technical indicators. A surface subsidence prediction method for extra-thick alluvium is proposed. Results show that top-coal caving mining exhibits the highest adaptability, followed by large-cutting-height mining and multi-slicing mining shows the weakest adaptability. The dynamic load method established based on the instability characteristics of the overburden caving arch can be used to guide the selection of hydraulic supports. Grouting-based modification and reinforcement at the bottom of the alluvium can enhance the integrity and water-resisting capacity of the thin bedrock-alluvium interface, promoting the formation of the towering roof beam structure, and weakening the concentrated transfer of thick alluvium load to the supports in the working face. The established surface subsidence prediction model reveals the mechanical mechanism of a surface subsidence exceeding 1.0. This study provides references for mining method selection, strata control, and subsidence mitigation in deeply buried thick coal seams under thin bedrock.

     

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