| 黄河流域陕北煤炭开采区厚砂岩对覆岩采动裂隙发育的影响及采煤保水建议 |
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| 引用本文： | 王双明,魏江波,宋世杰,王生全,孙涛.黄河流域陕北煤炭开采区厚砂岩对覆岩采动裂隙发育的影响及采煤保水建议[J].煤田地质与勘探,2022,50(12):1-11. |
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| 作者姓名： | 王双明 魏江波 宋世杰 王生全 孙涛 |
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| 作者单位： | 1.陕西省煤炭绿色开发地质保障重点实验室，陕西 西安 710054 |
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| 基金项目： | 国家自然科学基金项目(41402308)；榆林市科技计划重大项目(6130819001)；陕西省煤炭绿色开发地质保障重点实验室重点基金项目(DZBZ2022Z-03) |
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| 摘 要： | 煤炭开采活动导致的煤层顶板覆岩地质条件变化及采动裂隙发育是损害地下关键含水层的直接原因，也是造成矿区生态环境退化的根源。煤层顶板覆岩结构中发育的厚砂岩作为一种典型的地质条件，其对覆岩采动裂隙的发育规律具有重要的影响。为此，在分析研究区主采煤层赋存地质条件及其分布规律的基础上，选择陕北煤炭开采区曹家滩煤矿主采2?2煤层顶板覆岩为地质原型，采用FLAC3D数值模拟平台模拟分析了厚砂岩不同厚度和位置对覆岩采动裂隙发育形态和发育高度的影响，并以此提出了相应的“采煤保水”建议。结果表明:研究区2?2煤层顶板覆岩中厚砂岩平均厚度25 m，距2?2煤层平均间距76 m；厚砂岩距煤层30 m时，覆岩采动裂隙表现为“矩形—L形—马鞍形”的动态变化特征，距煤层70 m时表现为“L形—倒梯形—马鞍形”变化特征，距煤层大于95 m时全程表现为“马鞍形”特征；覆岩采动裂隙最大发育高度随厚砂岩层位的升高而先减小后增大；厚砂岩厚度H≥30 m、距煤层间距L>95 m，或H≥60 m、L>60 m时，可有效阻挡采动裂隙向上发育贯穿厚砂岩；在充分考虑厚砂岩对覆岩采动裂隙发育规律的影响，选择合适的空间位置和开采阶段进行合理的覆岩减损和保水防治，实现“边采边治、边采边护”的绿色开采模式。该研究成果可为黄河流域中游陕北煤矿区煤炭开采与生态环境保护协调发展提供理论指导。
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| 关 键 词： | 黄河流域 覆岩采动裂隙 厚砂岩 数值模拟 绿色开采 |
| 收稿时间： | 2022-08-02 |
Influence of thick sandstone on development of overburden mining fissures in northern Shaanxi coal mining area of Yellow River Basin and suggestions on water-preserved coal mining |
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| Institution: | 1.Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation, Xi’an University of Science and Technology, Xi’an 710054, China2.College of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, China3.Geological Research Institute for Coal Green Mining, Xi’an University of Science and Technology, Xi’an 710054, China |
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| Abstract: | The change of geological conditions of coal seam roof overburden and the development of mining fissures caused by coal mining activities are the direct causes of damage to the key underground aquifers, and also the root causes of ecological environment degradation in the mining area. As a typical geological condition, the thick sandstone developed in the overburden structure of the coal seam roof has an important impact on the development law of mining fissures in the overburden. Therefore, the influence of the thickness and location of different thick sandstones on the development morphology and height of overburden mining fractures was simulated and analyzed with the FLAC3D numerical simulation platform based on the analysis of the geological conditions and distribution rules of the main mining coal seams in the study area, taking the roof overburden of main mining coal seam 2?2 in Caojiatan Coal Mine of northern Shaanxi coal mining area as the geological prototype. Hence, suggestions were proposed for “water-preserved coal mining”. The results show that the thick sandstone in the roof overburden of coal seam 2?2 in the study area is 25 m thick on average, with an average spacing of 76 m from coal seam 2?2. Besides, the overburden mining fissures show the dynamic change in “Rectangle—L-shaped—Saddleback” characteristics for the thick sandstone 30 m away from the coal seam, “L-shaped—Inverted trapezoid—Saddleback” characteristics for the thick sandstone 70 m away from the coal seam, and “Saddleback” characteristics in the whole process for the thick sandstone 95 m away from the coal seam. The maximum development height of mining fissures in overburden decreases first and then increases with the increasing of thick sandstone horizon. The thickness of thick sandstone H≥30 m and the distance from the coal seam L>95 m, or H≥60 m and L>60 m could effectively prevent the upward development of mining fissures through the thick sandstone. In full consideration to the influence of thick sandstone on the development law of overburden mining fissures, reasonable measures were taken at appropriate spatial location and mining stage for overburden loss reduction and water conservation to realize the green mining mode of “mining while controlling, mining while protecting”. Generally, the research results could provide theoretical guidance for the coordinated development of coal mining and ecological environment protection in northern Shaanxi coal mining area of Yellow River Basin. |
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