Coupled Effects of Moisture Content and Inherent Clay Minerals on the Cohesive Strength of Remodelled Coal
Abstract
:1. Introduction
2. Materials and Methods
2.1. Sample Description and Preparation
2.2. Apparatus and Procedures
2.2.1. Direct Shear Test
2.2.2. X-ray Diffraction Observations
3. Results and Discussion
3.1. Direct Shear Test Results and Discussion
3.1.1. Shear Stress-Displacement Curves
3.1.2. Physical Properties Based on Mohr-Coulomb Failure Criterion
3.2. Effect of Moisture Content on Inherent Clay Minerals
3.3. Discussion about the Sunction Stress and Cohesive Strength of Remodelled Coal
4. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Coal Seam | W (%) | A (%) | V (%) | FC (%) | S (%) | CV (MJ/Kg) |
---|---|---|---|---|---|---|
NO. 2 | 0.85 | 28.35 | 22.97 | 68.73 | 3.89 | 34.47 |
Group Number | Moisture Content (%) | Density (kg/m3) | Normal Load (kPa) | Shear Velocity (mm/min) |
---|---|---|---|---|
G-1 | 6.6 | 1.30 | 100, 200, 300, 400 | 2.4 |
G-2 | 12.3 | 1.35 | ||
G-3 | 17.6 | 1.45 | ||
G-4 | 19.6 | 1.55 | ||
G-5 | 20.7 | 1.65 |
References | Materials | Range of Moisture Content (%) | Trend of Cohesive Strength |
---|---|---|---|
Wang et al. [9] | Coal | 1.57–6.55 | [1.57–3.07] increase; [3.07–6.55] decease |
Hu et al. [10] | Coal-bearing soil | 8.5–20.6 | [8.5–20.6] decease |
Cokca et al. [28] | Unsaturated clay | 18–28 | [18–23] increase; [23–28] decease |
Consoli et al. [29] | Cemented soils | 4.0–13.5 | [4.0–10] increase; [10–13.5] decease |
Liu and Zhu [30] | Mudstone | 10–20 | [10–13] increase; [13–20] decease |
Huang et al. [27] | Soil | 3.0–27.5 | [3.0–12.0] increase; [12.0–27.5] decease |
Minerals | Chemical Formula | Introduction |
---|---|---|
Kaolinite | Al2Si2O5(OH)4 | Easily broken and can be moulded or shaped, especially when wet. However, it does not expand when contacts with water. |
Smectite | (Al,Mg)2[Si4O10](OH)2·nH2O | An absorbent clay that can absorb large quantities of water, swelling to many times their original volume, and give rise to permanent suspensions of gel-like masses. |
Illite | K0.75(Al1.75R)[Si3.5Al0.5O10](OH)2 | A non-expanding clay and the capability of absorbing water is weaker than that of Smectite. |
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Zhang, H.; Wan, Z.; Ma, D.; Zhang, B.; Zhou, P. Coupled Effects of Moisture Content and Inherent Clay Minerals on the Cohesive Strength of Remodelled Coal. Energies 2017, 10, 1234. https://doi.org/10.3390/en10081234
Zhang H, Wan Z, Ma D, Zhang B, Zhou P. Coupled Effects of Moisture Content and Inherent Clay Minerals on the Cohesive Strength of Remodelled Coal. Energies. 2017; 10(8):1234. https://doi.org/10.3390/en10081234
Chicago/Turabian StyleZhang, Hongwei, Zhijun Wan, Dan Ma, Bo Zhang, and Peng Zhou. 2017. "Coupled Effects of Moisture Content and Inherent Clay Minerals on the Cohesive Strength of Remodelled Coal" Energies 10, no. 8: 1234. https://doi.org/10.3390/en10081234