Numerical Analysis and Experimental Study of Hard Roofs in Fully Mechanized Mining Faces under Sleeve Fracturing
Abstract
:1. Introduction
2. Mathematical Model of Sleeve-Fracturing Hard Roof
2.1. Working Mechanism of Single-Hole Controlled Fracturing
2.1.1. Working Mechanism of Single-Hole Two-Way Controlled Fracturing (TCF)
2.1.2. Working Mechanism of Single-Hole Unidirectional Controlled Fracturing (UCF)
2.2. Working Mechanism of Multi-Hole Controlled Fracturing
3. Simulation of Cracking Roofs with SFM (Sleeve Fracturing Method)
3.1. Model Establishment
Type | Compressive Strength (MPa) | Tensile Strength (MPa) | Cohesive Strength (MPa) | Internal Friction Angle (°) | Modulus of Elasticity (GPa) | Poisson’s Ratio (μ) | Density (kg·m−3) |
---|---|---|---|---|---|---|---|
Sandstone | 21.00 | 0.91 | 0.93 | 45 | 4.00 | 0.23 | 2600 |
3.2. Results
3.2.1. Model 1
3.2.2. Model 2
3.2.3. Model 3
4. Experiment on Cracking Roof with SFM
4.1. Method
4.2. Experiment Results
4.2.1. Similar Model 1
Measured Values | Borehole Spacing (mm) | ||
---|---|---|---|
100 | 160 | 200 | |
Sleeve Fracturing Pressure (MPa) | 13.8 | 18.4 | 23.6 |
4.2.2. Similar Model 2
Measured Values | Borehole Spacing (mm) | ||
---|---|---|---|
150 | 240 | 300 | |
Sleeve Fracturing Pressure (MPa) | 10.6 | 16.7 | 20.4 |
4.2.3. Similar Model 3
Measured Values | Borehole Spacing (mm) | ||
---|---|---|---|
200 | 320 | 400 | |
Sleeve Fracturing Pressure (MPa) | 9.2 | 10.7 | 17.6 |
5. Discussion
5.1. Similar Model 1
5.2. Similar Model 2
5.3. Similar Model 3
6. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Zheng, Z.; Xu, Y.; Li, D.; Dong, J. Numerical Analysis and Experimental Study of Hard Roofs in Fully Mechanized Mining Faces under Sleeve Fracturing. Minerals 2015, 5, 758-777. https://doi.org/10.3390/min5040523
Zheng Z, Xu Y, Li D, Dong J. Numerical Analysis and Experimental Study of Hard Roofs in Fully Mechanized Mining Faces under Sleeve Fracturing. Minerals. 2015; 5(4):758-777. https://doi.org/10.3390/min5040523
Chicago/Turabian StyleZheng, Zhitao, Ying Xu, Desheng Li, and Jianghui Dong. 2015. "Numerical Analysis and Experimental Study of Hard Roofs in Fully Mechanized Mining Faces under Sleeve Fracturing" Minerals 5, no. 4: 758-777. https://doi.org/10.3390/min5040523