Numerical Damping Calibration Study of Particle Element Method-Based Dynamic Relaxation Approach for Modeling Longwall Top-Coal Caving
Abstract
:1. Introduction
2. Basic Theory of Dynamic Relaxation Approach
2.1. Dynamic Relaxation Principle
2.2. The Principle of Progressive Failure Process of CDEM
3. Numerical Simulation Experiment of Drawing Coal in Extra-Thick Coal Seams
3.1. Numerical Model
- (1)
- Basic assumptions
- (2)
- Engineering background and numerical model
3.2. Simulation Scheme
3.3. Simulation Results
- (1)
- Results of the level 1 caving under different damping values
- (2)
- Results of the level 2 caving under different damping value
- (3)
- Results of the level 3 and level 4 caving under different damping value
4. Verification by Laboratory Experiments
4.1. Structure Design of Test Device
4.2. Scheme of Laboratory Similarity Experiment
4.3. Experimental Process and Results
5. Discussion
5.1. Calibration Parameters
5.2. Comparison of Results
6. Conclusions
- (1)
- By studying the results of different damping values in CDEM numerical simulation of top-coal caving, it is verified that the numerical damping value greatly influences the accuracy of top-coal caving modeling.
- (2)
- In the comparison of numerical simulation and similar simulation results, it is proposed that the angle, the maximum width, and the upper height of ‘V’ shape of coal drawing funnel are the indexes to determine the numerical damping in ‘large’ drawing. The angle and the maximum width of ‘V’ shape are the indexes to determine the numerical damping in a ‘medium’ drawing. By comparing the deviation of characteristic parameters between numerical simulation and similar simulation, it is concluded that 0.07 is the reasonable numerical damping value for CDEM numerical simulation of ‘large, medium, small and micro’ top-coal caving in Tashan coal mine.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Conflicts of Interest
References
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Rock Layer Type | Density/(kg/m3) | Elastic Modulus/GPa | Poisson’s Ratio | Tensile Strength/MPa | Cohesion/MPa | Internal Friction/° |
---|---|---|---|---|---|---|
Coal Seams | 1364 | 2 | 0.27 | 0 | 0 | 32.65 |
Immediate Roof | 2552 | 10 | 0.1 | 0 | 0 | 31.24 |
Top-Coal Drawing Sequence | Hydraulic Support Number |
---|---|
Level 1 or Large | 1#; 9#; 17#; 25# |
Level 2 or Medium | 5#; 13#; 21# |
Level 3 or Small | 3#; 7#; 11#; 15#; 19#; 23# |
Level 4 or Micro | 2#; 4#; 6#; 8#; 10#; 12#; 14#; 16#; 18#; 20#; 22#; 24# |
Damping Value | Hydraulic Support Number | The Angle of ‘V’ (°) | Average Angle of ‘V’ (°) | Maximum Influence Width of ‘V’ (m) | Average Maximum Influence Width of ‘V’ (m) | Upper Height of ‘V’ (m) | Upper Average Height of ‘V’ (m) |
---|---|---|---|---|---|---|---|
0.01 | 1# | 53 | 48.5 | 10.41 | 10.90 | 1.85 | 1.99 |
9# | 48 | 11.22 | 1.62 | ||||
17# | 47 | 10.81 | 2.69 | ||||
25# | 46 | 11.14 | 1.81 | ||||
0.03 | 1# | 41 | 41.25 | 10.23 | 9.47 | 1.27 | 1.51 |
9# | 43 | 9.11 | 1.44 | ||||
17# | 36 | 9.24 | 1.5 | ||||
25# | 45 | 9.31 | 1.82 | ||||
0.07 | 1# | 38 | 35.5 | 8.85 | 8.69 | 1.32 | 1.51 |
9# | 34 | 8.97 | 1.57 | ||||
17# | 36 | 9.08 | 1.53 | ||||
25# | 34 | 7.85 | 1.62 | ||||
0.11 | 1# | 29 | 29.25 | 8.23 | 7.43 | 1.2 | 1.69 |
9# | 30 | 6.71 | 1.49 | ||||
17# | 32 | 7.68 | 1.98 | ||||
25# | 26 | 7.09 | 2.07 | ||||
0.15 | 1# | 17 | 17 | 6.42 | 6.43 | 2.93 | 2.63 |
9# | 17 | 6.46 | 1.89 | ||||
17# | 19 | 6.61 | 2.65 | ||||
25# | 15 | 6.24 | 3.06 |
Damping Value | Hydraulic Support Number | Angle of ‘V’ (°) | Average Angle of ‘V’ (°) | Maximum Influence Width of ‘V’ (m) | Average Maximum Influence Width of ‘V’ (m) |
---|---|---|---|---|---|
0.01 | 5# | 33 | 64 | 6.3 | 6.88 |
13# | 76 | 7.53 | |||
21# | 83 | 6.81 | |||
0.03 | 5# | 54 | 56.7 | 6.1 | 6.72 |
13# | 52 | 6.73 | |||
21# | 64 | 7.34 | |||
0.07 | 5# | 42 | 43.3 | 7.36 | 7.15 |
13# | 44 | 7.03 | |||
21# | 44 | 7.05 | |||
0.11 | 5# | 25 | 30.7 | 8.17 | 7.74 |
13# | 36 | 7.21 | |||
21# | 31 | 7.84 | |||
0.15 | 5# | 12 | 10 | 8.17 | 7.88 |
13# | 8 | 7.71 | |||
21# | 10 | 7.75 |
Coal Drawing Sequence | Type of Coal Drawing Opening | Hydraulic Support Number | Coal Port Size |
---|---|---|---|
1 | Large | 6#; 14# | 100 mm |
2 | Medium | 2#; 10#; 18# | 100 mm |
3 | Small | 4#; 8#; 12#; 16# | 100 mm |
4 | Micro | 3#; 5#; 7#; 9#; 11#; 13#; 15#; 17#; 19# | 100 mm |
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Li, H.; Li, D.; Zhang, W.; Li, H.; Wang, S.; Wang, H.; Xu, X.; Li, Z. Numerical Damping Calibration Study of Particle Element Method-Based Dynamic Relaxation Approach for Modeling Longwall Top-Coal Caving. Energies 2021, 14, 2348. https://doi.org/10.3390/en14092348
Li H, Li D, Zhang W, Li H, Wang S, Wang H, Xu X, Li Z. Numerical Damping Calibration Study of Particle Element Method-Based Dynamic Relaxation Approach for Modeling Longwall Top-Coal Caving. Energies. 2021; 14(9):2348. https://doi.org/10.3390/en14092348
Chicago/Turabian StyleLi, Hongbin, Dongyin Li, Weiyu Zhang, Huamin Li, Shen Wang, Hao Wang, Xiaokai Xu, and Zhenfeng Li. 2021. "Numerical Damping Calibration Study of Particle Element Method-Based Dynamic Relaxation Approach for Modeling Longwall Top-Coal Caving" Energies 14, no. 9: 2348. https://doi.org/10.3390/en14092348