单轴压缩条件下不同含水率煤体裂纹扩展及破坏模式研究

卢卫永; 刘琦; 屈丽娜; 张海军

doi:10.13272/j.issn.1671-251x.2022040036

单轴压缩条件下不同含水率煤体裂纹扩展及破坏模式研究

doi: 10.13272/j.issn.1671-251x.2022040036

卢卫永^{1, 2,},
刘琦^3, ,,
屈丽娜³,
张海军⁴

1.
吕梁学院矿业工程系, 山西吕梁　033001
2.
吕梁市智慧煤矿工程技术研究中心,山西吕梁　033001
3.
中原工学院能源与环境学院, 河南郑州　451191
4.
山西煤炭运销集团锦瑞煤业有限公司, 山西吕梁　033000

基金项目: 山西省基础研究计划资助项目（20210302124633）；吕梁市平台基地建设项目（2021GCZX-1-46）；国家自然科学基金项目（51804355）。

详细信息

作者简介:
卢卫永（1987—），男，河南沈丘人，副教授，博士，主要研究方向为煤岩体水力致裂，E-mail:luwyll@126.com

通讯作者:
刘琦（1972—），男，河南郑州人，副教授，博士，主要研究方向为矿山安全与灾害防治，E-mail:liuqzut@126.com

中图分类号: TD712
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出版历程
- 收稿日期: 2022-04-13
- 修回日期: 2022-08-06
- 网络出版日期: 2022-08-09

Study on coal crack propagation and failure mode with different moisture content under uniaxial compression

LU Weiyong^{1, 2
,},
LIU Qi^{3
, ,},
QU Lina³,
ZHANG Haijun⁴

1.
Department of Mining Engineering, Lüliang University, Lüliang 033001, China
2.
Lüliang Engineering Research Center of Intelligent Coal Mine, Lüliang 033001, China
3.
School of Energy and Environment, Zhongyuan University of Technology, Zhengzhou 451191, China
4.
Jinrui Coal Industry Co., Ltd. of Shanxi Coal Transportation and Marketing Group, Lüliang 033000, China

摘要

摘要: 为研究水分侵入对受载煤体裂纹扩展及破坏模式的影响，开展了不同含水率煤体单轴压缩试验及声发射监测，对比分析了不同含水率下受载煤体应力−应变特征、宏观破坏形态及累计振铃计数的变化规律。单轴压缩试验结果表明，随着含水率增加，煤体单轴抗压强度及弹性模量持续降低，且峰后阶段内煤体应力下降速率逐渐平缓，煤样宏观破裂模式由典型的脆性破坏转变为剪切−拉张组合破坏。声发射监测结果表明，随着煤体含水率增加，累计振铃计数不断降低，而累计振铃计数曲线斜率相应增大，说明水分侵入会降低煤体裂隙发育时的能量释放，但加剧了煤体内部结构损伤。研究结果表明，水分的侵入一定程度上削弱了裂隙表面晶体颗粒间的相互摩擦，增加了煤体滑移破坏的可能性；同时水分侵入也减小了煤体表面活性能，导致煤样受载过程中产生的裂隙数量显著增多，造成煤体宏观力学强度大幅降低。
- 含水煤体 /
- 含水率 /
- 煤体裂纹扩展 /
- 煤体破坏模式 /
- 单轴压缩 /
- 声发射 /
- 应力−应变 /
- 累计振铃计数
Abstract: In order to study the influence of moisture intrusion on crack propagation and failure mode of loaded coal, uniaxial compression tests and acoustic emission monitoring of coal with different moisture contents are carried out. The stress-strain characteristics, macroscopic failure patterns and change law of cumulative ringing counts of loaded coal with different moisture contents are compared and analyzed. The results of uniaxial compression tests show that with the increase of moisture content, the uniaxial compressive strength and elastic modulus of coal decrease continuously. The stress drop rate of coal gradually slows down in the post-peak stage. The macroscopic failure mode of coal samples changes from typical brittle failure to shear-tension combined failure. The acoustic emission monitoring results show that the cumulative ringing counts decreases with the increase of coal moisture content. The cumulative ringing counts curve's slope increases correspondingly, indicating that moisture intrusion can reduce the energy release when the coal cracks develop. However, the moisture intrusion aggravates the internal structure damage of coal. The results show that the water intrusion weakens the friction between crystal particles on the surface of cracks to some extent, and increases the possibility of coal sliding failure. At the same time, the water intrusion also reduces the surface active energy of the coal, resulting in a significant increase in the number of cracks generated during the loading process of the coal sample. This leads to a large drop in the macroscopic mechanical strength of the coal.
- water-bearing coal /
- moisture content /
- coal crack propagation /
- coal failure mode /
- uniaxial compression /
- acoustic emission /
- stress-strain /
- cumulative ringing counts

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图 1 试验方案

Figure 1. Experimental scheme

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图 2 煤样含水率变化曲线

Figure 2. Change curves of coal samples moisture content

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图 3 不同含水率煤样应力−应变曲线

Figure 3. Stress-strain curves of coal samples with different moisture content

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图 4 不同含水率煤样破坏模式

Figure 4. Failure modes of coal samples with different moisture content

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图 5 不同含水率煤样应力和累计振铃计数随时间变化曲线

Figure 5. Change curve with the time of stress and cumulative ring count of coal samples with different moisture content

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图 6 不同含水率煤样累计振铃计数对比曲线

Figure 6. Comparison curves of cumulative ringing counts of coal samples with different moisture content

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表 1 煤样基本力学参数

Table 1. Basic mechanics parameters of coal samples

参数	值
真密度/（kg·m⁻³）	1 365
抗压强度/MPa	20.75
抗拉强度/MPa	2.61
黏聚力/MPa	4.07
内摩擦角/（°）	27.64
弹性模量/GPa	1.82
泊松比	0.31

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表 2 不同含水率煤样单轴压缩试验结果

Table 2. Uniaxial compression test results of coal samples with different moisture content

煤样编号	含水率/%	密度/ （kg·m⁻³）	抗压强度/MPa	应变/%	弹性模量/GPa
A−1	0	1 379.18	20.72	1.36	1.85
A−2	0	1 371.89	21.37	1.43	1.81
A−3	0	1 344.34	20.16	1.33	1.79
B−1	6.83	1 521.97	18.58	1.43	1.70
B−2	6.54	1 485.74	19.04	1.39	1.79
B−3	6.98	1 498.80	18.33	1.44	1.68
C−1	9.61	1 578.17	14.43	1.47	1.53
C−2	10.03	1 468.79	15.74	1.50	1.67
C−3	9.84	1 527.36	16.84	1.52	1.73
D−1	10.89	1 481.90	12.59	1.51	1.24
D−2	11.08	1 531.41	14.93	1.61	1.39
D−3	11.11	1 564.97	13.97	1.52	1.37

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