Correlational Analytical Characterization of Energy Dissipation-Liberation and Acoustic Emission during Coal and Rock Fracture Inducing by Underground Coal Excavation
Abstract
:1. Introduction
2. Test Scheme
2.1. Crustal Stress Setting and Physical Property Analysis
2.2. Experimental Facility and Monitoring Technique
3. Coal Fracturing Mechanism
4. Analytical Discussion
5. Conclusions
Author Contributions
Acknowledgments
Conflicts of Interest
Appendix A
Sample Number | Mass(g) | Geometric Dimension (mm) | Volume(cm3) | Density(g/cm−3) | Appearance Description | |||
---|---|---|---|---|---|---|---|---|
X-axis | Y-axis | Z-axis | ||||||
LXMT-01 | 283 | 59.9 | 60.1 | 60.2 | 216.719 | 1.306 | Apparent through cracks in Y-axis | |
LXMT-02 | 291 | 60.3 | 61.2 | 59.8 | 220.684 | 1.319 | Apparent through cracks in all axes | |
LXMT-03 | 283 | 60.0 | 60.5 | 59.7 | 216.711 | 1.306 | Apparent tiny cracks in all axes | |
LXMT-04 | 278 | 59.4 | 59.9 | 59.6 | 212.060 | 1.311 | Apparent through cracks in Y-axis | |
LXMT-05 | 288 | 60.3 | 60.1 | 60.0 | 217.442 | 1.324 | Apparent cracks in both X- and Z-axes | |
LXMT-06 | 289 | 60.7 | 59.9 | 60.4 | 219.610 | 1.316 | Apparent tiny cracks in all axes | |
LXMT-07 | 275 | 59.6 | 59.8 | 59.3 | 211.350 | 1.301 | Apparent tiny cracks in all axes | |
LXYT-01 | 580 | 59.9 | 60.3 | 59.8 | 215.996 | 2.685 | Whole is more complete with small surface cracks | |
LXYT-02 | 540 | 59.2 | 59.8 | 61.8 | 218.782 | 2.638 | Whole is more complete with small surface cracks | |
LXYT-03 | 573 | 60.0 | 60.2 | 59.5 | 214.914 | 2.666 | Clear grain, through cracks in X,Y- and Y,Z-axis | |
LXYT-04 | 549 | 59.0 | 58.9 | 59.6 | 207.116 | 2.651 | Clear grain, through cracks in X,Y- and Y,Z-axis | |
LXYT-05 | 561 | 60.1 | 59.3 | 59.0 | 210.272 | 2.668 | Whole is more complete with small surface cracks | |
LXYT-06 | 594 | 60.7 | 60.2 | 60.6 | 221.441 | 2.682 | Clear grain, through cracks in X,Y- and Y,Z-axis | |
LXYT-07 | 592 | 61.0 | 59.8 | 60.0 | 218.868 | 2.705 | Apparent cracks in both X- and Z-axes | |
Lithology | Discrete parameter | LX (mm) | LY (mm) | LZ (mm) | Mass (g) | Density (g/cm−3) | ||
Coal mass | 60.0 | 60.2 | 59.5 | 284 | 1.312 | |||
E | 0.447 | 0.491 | 0.537 | 5.902 | 0.008 | |||
ζ | 0.745 | 0.816 | 0.903 | 2.078 | 0.610 | |||
Rock | 60.0 | 59.6 | 59.6 | 570 | 2.671 | |||
E | 0.725 | 0.642 | 0.607 | 20.781 | 0.0223 | |||
ζ | 1.208 | 1.077 | 1.018 | 3.646 | 0.835 |
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Name | Lithology | Thickness (m) | Description | |||||
Main Roof | Shale | 1.90 | hard, dark grey, and lamellar | |||||
Immediate Roof | Siltstones | 0.70 | Lamellar and joint obviously | |||||
False Roof | Shale | 0.10 | Soft and joint obviously | |||||
Coal Seam Floor | Shale | 0.55 | Joint and fragile | |||||
Serial number | Maceral composition(%) | |||||||
Vitrinite | Average | Inertinite | Average | Liptinite | Average | |||
B3-6 | 33.50–62.60 | 46.60 | 37.40–65.60 | 52.80 | 0.00–1.90 | 0.60 | ||
Organic matter(%) | Inorganic matter(%) | Vitrinite reflectance(%) | Microlithotype | |||||
86.35 | 13.65 | 0.67 | vitrinertite |
Sample Serial Number | σp (MPa) | σr (MPa) | εp (10−3) | Et (MPa) | Eb (MPa) | dε/dt (10−3/s) | |
---|---|---|---|---|---|---|---|
LXMT-01 | 18.57 | 11.53 | 98.30 | 595 | 110 | 0.56 | |
LXMT-02 | 14.37 | 7.55 | 85.75 | 956 | 91 | ||
LXMT-03 | 12.45 | 6.44 | 69.60 | 410 | 122 | ||
LXMT-04 | 11.74 | 6.11 | 52.62 | 660 | 142 | ||
LXMT-05 | 9.72 | 4.91 | 78.47 | 518 | 73 | ||
LXMT-06 | 17.26 | 8.87 | 68.20 | 682 | 148 | ||
LXMT-07 | 17.99 | 12.61 | 96.42 | 780 | 109 | ||
LXYT-01 | 25.36 | 12.52 | 72.30 | 877 | 231 | 0.55 | |
LXYT-02 | 15.48 | 9.94 | 70.40 | 727 | 128 | ||
LXYT-03 | 19.05 | 13.68 | 39.96 | 590 | 330 | ||
LXYT-04 | 12.43 | 10.81 | 40.08 | 440 | 259 | ||
LXYT-05 | 37.26 | 18.48 | 34.41 | 764 | 668 | ||
LXYT-06 | 43.13 | 24.97 | 54.83 | 716 | 525 | ||
LXYT-07 | 39.03 | 19.87 | 52.50 | 689 | 622 | ||
Lithology | Discrete parameter | σp | σr | εp | Et | Eb | |
Coal | 14.59 | 8.29 | 78.48 | 657 | 114 | ||
E | 3.44 | 2.88 | 16.44 | 178 | 27 | ||
ζ | 23.578 | 34.741 | 20.948 | 27.093 | 23.684 | ||
Rock | 27.39 | 15.75 | 52.07 | 686 | 395 | ||
E | 12.38 | 5.51 | 15.03 | 138 | 210 | ||
ζ | 45.199 | 34.984 | 28.865 | 20.117 | 53.165 |
Lithology | Sample Number | σKaiser (MPa) | Ψ (MJ/m3) | U (J) | Kt (MJ/m3) | Ψ/Kt | ΣEAE (J) | AE Stage | EAE (J) | EAE-II/ΣEAE (%) |
---|---|---|---|---|---|---|---|---|---|---|
Coal sample | LXMT-01 | 1.04 | 0.491 | 106.41 | 0.290 | 1.445 | 0.477 | I | 0.014 | 2.94 |
II | 0.022 | 4.64 | ||||||||
III | 0.330 | 69.15 | ||||||||
IV | 0.111 | 23.27 | ||||||||
LXMT-02 | 2.51 | 0.331 | 73.05 | 0.108 | 3.067 | 0.101 | I | 0.001 | 0.99 | |
II | 0.007 | 6.95 | ||||||||
III | 0.073 | 72.26 | ||||||||
IV | 0.020 | 19.80 | ||||||||
LXMT-03 | 1.54 | 0.356 | 77.15 | 0.189 | 1.883 | 0.514 | I | 0.001 | 0.19 | |
II | 0.033 | 6.52 | ||||||||
III | 0.299 | 58.27 | ||||||||
IV | 0.180 | 35.02 | ||||||||
LXMT-04 | 1.21 | 0.285 | 60.44 | 0.104 | 2.740 | 0.172 | I | 0.001 | 0.58 | |
II | 0.013 | 7.83 | ||||||||
III | 0.156 | 90.42 | ||||||||
IV | 0.002 | 1.17 | ||||||||
LXMT-05 | 1.11 | 0.324 | 70.45 | 0.182 | 1.779 | 0.546 | I | 0.012 | 2.20 | |
II | 0.039 | 7.08 | ||||||||
III | 0.461 | 84.49 | ||||||||
IV | 0.034 | 6.23 | ||||||||
LXMT-06 | 1.51 | 0.418 | 91.80 | 0.218 | 1.916 | 0.552 | I | 0.012 | 2.17 | |
II | 0.031 | 5.59 | ||||||||
III | 0.391 | 70.83 | ||||||||
IV | 0.118 | 21.41 | ||||||||
LXMT-07 | 1.42 | 0.479 | 101.24 | 0.207 | 2.375 | 0.499 | I | 0.018 | 3.61 | |
II | 0.024 | 4.81 | ||||||||
III | 0.429 | 85.97 | ||||||||
IV | 0.028 | 5.61 | ||||||||
Rock sample | LXYT-01 | 1.14 | 2.066 | 446.31 | 0.367 | 1.98 | 0.293 | I | 0.007 | 2.39 |
II | 0.078 | 26.55 | ||||||||
III | 0.206 | 70.37 | ||||||||
IV | 0.002 | 0.69 | ||||||||
LXYT-02 | 1.88 | 1.917 | 419.41 | 0.165 | 4.158 | 0.215 | I | 0.002 | 0.93 | |
II | 0.059 | 27.57 | ||||||||
III | 0.142 | 66.38 | ||||||||
IV | 0.011 | 5.12 | ||||||||
LXYT-03 | 1.92 | 1.848 | 397.22 | 0.308 | 2.165 | 0.240 | I | 0.001 | 0.42 | |
II | 0.067 | 28.07 | ||||||||
III | 0.157 | 66.09 | ||||||||
IV | 0.013 | 5.42 | ||||||||
LXYT-04 | 1.17 | 1.551 | 321.19 | 0.176 | 3.237 | 0.114 | I | 0.001 | 0.88 | |
II | 0.035 | 30.48 | ||||||||
III | 0.070 | 61.63 | ||||||||
IV | 0.008 | 7.01 | ||||||||
LXYT-05 | 2.21 | 3.904 | 820.87 | 0.455 | 2.364 | 0.242 | I | 0.001 | 0.41 | |
II | 0.043 | 17.83 | ||||||||
III | 0.109 | 44.98 | ||||||||
IV | 0.089 | 36.78 | ||||||||
LXYT-06 | 2.31 | 3.537 | 783.21 | 0.650 | 1.570 | 0.384 | I | 0.006 | 1.57 | |
II | 0.074 | 19.18 | ||||||||
III | 0.238 | 62.07 | ||||||||
IV | 0.066 | 17.18 | ||||||||
LXYT-07 | 2.44 | 3.662 | 801.47 | 0.557 | 1.866 | 0.194 | I | 0.001 | 0.52 | |
II | 0.036 | 18.71 | ||||||||
III | 0.076 | 39.02 | ||||||||
IV | 0.081 | 41.75 |
Parameter | a | a0 | 1/b | Kt |
---|---|---|---|---|
Coal sample | 1.903 | −5.841 | −0.171 | 0.162 |
Rock sample | 3.267 | −13.636 | −0.073 | 0.547 |
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Shan, P.; Lai, X.; Liu, X. Correlational Analytical Characterization of Energy Dissipation-Liberation and Acoustic Emission during Coal and Rock Fracture Inducing by Underground Coal Excavation. Energies 2019, 12, 2382. https://doi.org/10.3390/en12122382
Shan P, Lai X, Liu X. Correlational Analytical Characterization of Energy Dissipation-Liberation and Acoustic Emission during Coal and Rock Fracture Inducing by Underground Coal Excavation. Energies. 2019; 12(12):2382. https://doi.org/10.3390/en12122382
Chicago/Turabian StyleShan, Pengfei, Xingping Lai, and Xiaoming Liu. 2019. "Correlational Analytical Characterization of Energy Dissipation-Liberation and Acoustic Emission during Coal and Rock Fracture Inducing by Underground Coal Excavation" Energies 12, no. 12: 2382. https://doi.org/10.3390/en12122382