| 孙思洋,李和万*,王来贵,刘戬,张子恒.液氮冷加载作用下煤样渗透特性研究[J].实验力学,2023,38(4):517~529 |
| 液氮冷加载作用下煤样渗透特性研究 |
| Study on permeability characteristics of coal samples under liquid nitrogen cold loading |
| 投稿时间：2022-10-23 修订日期：2022-11-27 |
| DOI：10.7520/1001-4888-22-265 |
| 中文关键词: 液氮冷加载 煤样损伤 波速衰减率 孔隙量 渗透率 |
| 英文关键词:liquid nitrogen cold loading coal sample damage the attenuation rate of wave velocity porosity permeability |
| 基金项目:国家自然科学基金青年基金资助项目(51704142)；国家重点研发计划(2017YFC1503102)；辽宁省博士科研启动基金计划项目(2019-BS-115) |
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| 摘要点击次数: 2003 |
| 全文下载次数: 40 |
| 中文摘要: |
| 为了研究液氮冷加载对煤样渗透特性的影响，采用试验研究和理论分析相结合的方法，对不同冷加载周期煤样的孔隙、裂隙结构损伤破坏变化规律、各物理力学性质以及渗透特性展开研究，通过电镜扫描、波速测试、渗透试验和单轴压缩试验分别得到不同冷加载周期前后煤样裂隙的发育情况、波速衰减率、孔隙量、抗压强度以及渗透率的变化。试验结果表明：(1)液氮冷加载能促进煤样裂隙萌生和发育，有效地连接相对独立的裂隙结构，形成交织的裂隙网络，增大煤样气体流量，从而提高煤样渗透率。(2)温差效应与水冰相变的共同作用对煤样渗透性也有较强的促进作用；(3)随着冷加载周期的循环，煤样裂隙扩展宽度、扩展率均逐渐增大，力学性能减弱，抗压能力越来越差，煤样整体损伤程度严重，渗透率呈指数增长，比煤样初始渗透率提高了16.76倍。 |
| 英文摘要: |
| To study the influence of liquid nitrogen cold loading on the permeability characteristics of coal samples, the research method combining experimental research and theoretical analysis was used to study the change law of pore and fracture structure damage and damage, physical and mechanical properties, and permeability characteristics of coal samples under different cold loading cycles. The development of coal samples′ cracks before and after different cold loading cycles were obtained by scanning electron microscope, wave velocity test, permeability test, uniaxial compression test, change of wave velocity attenuation rate, pore volume, compressive strength, and permeability. The test results show that (1) cold loading with liquid nitrogen can effectively promote the initiation and development of coal sample fractures, effectively connect relatively independent fracture structures, form interwoven fracture networks, increase the gas flow of coal samples, and thus improve the permeability of coal samples; (2) The combined effect of temperature difference effect and water ice phase change also has a strong promoting effect on the permeability of coal samples; (3) With the cycle of cold loading cycle, the crack expansion width and expansion rate of coal samples gradually increase, the mechanical properties are weakened, the compressive strength is getting worse and worse, the overall damage degree of coal samples is serious, and the permeability increases exponentially, increasing by 16.76 times. |
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