| 基于CT三维重建的注水煤岩体裂隙扩展规律研究 |
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| 引用本文： | 毛彦军,陈曦,范超男,葛少成,李文璞. 基于CT三维重建的注水煤岩体裂隙扩展规律研究[J]. 岩土力学, 2022, 43(6): 1717-1726. DOI: 10.16285/j.rsm.2021.1609 |
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| 作者姓名： | 毛彦军 陈曦 范超男 葛少成 李文璞 |
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| 作者单位： | 1. 太原理工大学 安全与应急管理工程学院，山西 太原 030024；2. 太原理工大学 材料科学与工程学院，山西 太原 030024 |
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| 基金项目： | 国家自然科学基金（No.52174195,No.51804211）；;山西省应用基础研究计划（No.201901D211037）~~； |
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| 摘 要： | 针对煤层注水防尘过程中注水压力设置不合理、注水渗流效果差等问题，采用CT扫描技术与RFPA软件相结合的方法，构建了可以表征注水煤岩体内部孔裂隙结构的三维细观非均匀渗流损伤数值模型。通过对经过CT三维重构的煤岩模型进行不同注水压力的渗流损伤模拟，研究了煤层注水压力对煤样的渗流破坏、渗透率演化及声发射特性变化的影响；并通过对重构的煤岩模型进行缩放处理，研究了煤岩尺寸对煤样的渗流破坏和声发射变化的影响。研究结果表明：在煤样微观裂隙扩展过程中，随着注水压力的递增，煤样损伤单元数、渗流运动的渗流场分布范围、渗透率、声发射数目和能量总体呈上升趋势，局部范围内有波动发生，发生波动的原因是由于渗流运动的渗流场与煤样裂隙内部应力场发生临界反应，致使煤样破坏单元位置发生改变；煤样渗透率由3.82×10−5 μm2上升至0.314 μm2，孔隙率由5.45%上升至48.45%，揭示了煤岩体裂隙总体上随注水压力增大而不断扩展贯通，局部上随注水压力增大而扩展趋势有所下降的影响规律；随着煤样尺寸的增加，注水破坏后煤样的孔隙率呈现先下降后逐渐平稳的趋势，声发射特性变化趋势正好与之相反，表明煤样的尺寸对注水煤岩渗流破坏有显著影响，但当煤样尺寸超过40 mm时，煤样尺寸对注水煤岩渗流破坏的影响趋于稳定。CT扫描技术与RFPA软件相结合的方法能够有效模拟注水煤岩的裂隙渗流扩展行为。
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| 关 键 词： | 煤层注水 裂隙扩展 渗透率 尺寸效应 |
| 收稿时间： | 2021-09-21 |
| 修稿时间： | 2022-04-29 |
Crack network evolution of water injection coal and rock mass by means of 3D reconstruction |
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| MAO Yan-jun,CHEN Xi,FAN Chao-nan,GE Shao-cheng,LI Wen-pu. Crack network evolution of water injection coal and rock mass by means of 3D reconstruction[J]. Rock and Soil Mechanics, 2022, 43(6): 1717-1726. DOI: 10.16285/j.rsm.2021.1609 |
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| Authors: | MAO Yan-jun CHEN Xi FAN Chao-nan GE Shao-cheng LI Wen-pu |
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| Affiliation: | 1. College of Safety and Emergency Management Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China;2. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China |
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| Abstract: | In view of the unreasonable setting of water injection pressure and poor water injection seepage effect in the process of coal seam water infusion and dust prevention, a three-dimensional meso non-uniform seepage damage numerical model which can characterize the internal pore and fracture structure of water injection coal and rock mass is constructed by using the method of CT scanning technology and RFPA software. Through the seepage damage simulation of coal rock model reconstructed by CT with different water injection pressures, the influence of water injection pressure on the seepage damage permeability, evolution and acoustic emission characteristics of coal rock sample was studied. The effect of coal rock size on seepage damage and acoustic emission of coal rock samples is studied by scaling the reconstructed coal rock model. The results show that in the process of micro fracture propagation of coal sample, with the increase of water injection pressure, the number of damage units, seepage movement distribution range of seepage field, permeability, acoustic emission number and energy of coal sample generally show an upward trend, and there are fluctuations in local area. The reason for the fluctuation is the critical reaction between the seepage field and the internal stress field of coal sample fracture, resulting in the change of the position of coal sample failure unit. The permeability of coal samples increases from 3.82×10−5 μm2 to 0.314 μm2, and the porosity increases from 5.45% to 48.45%, which reveals the influence law that the fractures of coal and rock mass continue to expand and penetrate with the increase of water injection pressure on the whole, and the expansion trend decreases with the increase of water injection pressure on the part. With the increase of coal sample size, the porosity of the coal sample after the water injection failure shows a trend of first decreasing and then gradually stabilizing, and the change trend of acoustic emission characteristic is just the opposite, indicating that the coal sample size has a significant impact on the water injection coal rock seepage failure. However, the impact of the coal sample size on the water injection coal rock seepage failure tends to be stable when the coal sample size exceeds 40 mm. The combination of CT scanning technology and RFPA software can effectively simulate the fracture seepage propagation behavior of water injection coal and rock. |
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| Keywords: | coal seam water infusion fracture expansion permeability size effect |
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