Strength Characteristics and Failure Mechanism of Cemented Super-Fine Unclassified Tailings Backfill
Abstract
:1. Introduction
2. Materials and Methods
2.1. Tailings, Binder and Mixing Water
2.2. Specimen Preparation
2.3. Uniaxial Compression Tests
3. Results and Discussion
3.1. Strength Characteristics of CSUTB
3.1.1. Effect of CTR
3.1.2. Effect of Solid Content
3.1.3. Effect of Curing Time
3.2. Sensitivity of Strength to Influencing Factors
3.3. Failure Process and Mechanism of CSUTB
4. Conclusions
- (1)
- ZGIM tailings is a super-fine and alkaline tailings with high quality and activity. The non-uniform coefficient of the tailings is 8.6, meaning a good gradation.
- (2)
- The effects of the CTR, solid content and curing time on the UCS of CSUTB are investigated. When the other two factors are fixed, the UCS of CSUTB increases exponentially with the increase of CTR and solid content, while increases linearly with curing time. The sensitivity of UCS to curing time is strongest, with a correlation degree of 0.728, and the sensitivity is weakest to solid content, with a correlation degree of 0.689.
- (3)
- The failure process of CSUTB is divided into four stages including initial deformation, linear elastic deformation, yield deformation and complete failure. The damage of the CSUTB is attributed to the accumulation of micro cracks and concentration of partial stresses, and the evolution of damage leads to complete failure of CSUTB.
- (4)
- Future studies are required to investigate the strength characteristics of CSUTB under complex mechanical conditions, explore the hydration mechanism of CSUTB and compare it to normal CPB, and test the long term performance of CSUTB.
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Characteristic Diameter | d10 | d50 | d60 | d90 | d100 |
---|---|---|---|---|---|
Size (μm) | 2.17 | 14.2 | 18.7 | 82.9 | 211 |
Composition | CaO | SiO2 | Fe2O3 | MgO | Al2O3 | SO3 | K2O | Na2O | TiO2 |
---|---|---|---|---|---|---|---|---|---|
Tailings | 44.41 | 20.91 | 16.39 | 11.30 | 3.22 | 2.23 | 0.52 | 0.39 | 0.10 |
OPC | 60.51 | 22.86 | 3.35 | 1.57 | 5.45 | 3.01 | 0.56 | 0.25 | 0.11 |
CTR | Solid Content | Curing Time (Day) |
---|---|---|
1:4 | 65% | 3 |
1:6 | 68% | 7 |
1:8 | 70% | 14 |
1:10 | 73% | 28 |
CTR | Curing Time (Day) | Solid Content | |||
---|---|---|---|---|---|
65% | 68% | 70% | 73% | ||
1:4 | 3 | 0.41 | 0.64 | 0.84 | 0.96 |
7 | 0.83 | 1.02 | 1.34 | 1.58 | |
14 | 1.47 | 1.68 | 2.16 | 2.40 | |
28 | 2.04 | 2.26 | 2.80 | 2.97 | |
1:6 | 3 | 0.35 | 0.37 | 0.45 | 0.57 |
7 | 0.63 | 0.68 | 0.84 | 0.95 | |
14 | 1.07 | 1.14 | 1.30 | 1.55 | |
28 | 1.42 | 1.46 | 1.64 | 1.82 | |
1:8 | 3 | 0.24 | 0.26 | 0.33 | 0.38 |
7 | 0.43 | 0.45 | 0.50 | 0.53 | |
14 | 0.84 | 0.97 | 1.08 | 1.17 | |
28 | 1.17 | 1.29 | 1.33 | 1.40 | |
1:10 | 3 | 0.17 | 0.19 | 0.21 | 0.24 |
7 | 0.35 | 0.38 | 0.42 | 0.43 | |
14 | 0.60 | 0.66 | 0.68 | 0.73 | |
28 | 0.83 | 0.86 | 0.89 | 0.94 |
Curing Time (Day) | Fitting Type | Solid Content | ||||
---|---|---|---|---|---|---|
65% | 68% | 70% | 73% | Average | ||
3 | linear | 0.9760 | 0.8712 | 0.7986 | 0.9216 | 0.8919 |
exponential | 0.9533 | 0.9991 | 0.9836 | 0.9968 | 0.9832 | |
7 | linear | 0.9554 | 0.8834 | 0.8765 | 0.9143 | 0.9074 |
exponential | 0.9816 | 0.9884 | 0.9845 | 0.9564 | 0.9778 | |
14 | linear | 0.9695 | 0.9282 | 0.8905 | 0.9448 | 0.9333 |
exponential | 0.9909 | 0.9309 | 0.9401 | 0.9581 | 0.9550 | |
28 | linear | 0.9414 | 0.8974 | 0.8670 | 0.9051 | 0.9027 |
exponential | 0.9694 | 0.9510 | 0.9606 | 0.9790 | 0.9650 |
Curing Time (Day) | Fitting Type | CTR | ||||
---|---|---|---|---|---|---|
1:4 | 1:6 | 1:8 | 1:10 | Average | ||
3 | linear | 0.8883 | 0.9118 | 0.9324 | 0.9797 | 0.9281 |
exponential | 0.8776 | 0.9348 | 0.9375 | 0.9837 | 0.9334 | |
7 | linear | 0.9739 | 0.9374 | 0.9347 | 0.9651 | 0.9528 |
exponential | 0.9751 | 0.9410 | 0.9356 | 0.9593 | 0.9528 | |
14 | linear | 0.9481 | 0.9320 | 0.9888 | 0.9974 | 0.9666 |
exponential | 0.9484 | 0.9492 | 0.9807 | 0.9964 | 0.9687 | |
28 | linear | 0.9232 | 0.9187 | 0.9695 | 0.9832 | 0.9487 |
exponential | 0.9235 | 0.9242 | 0.9701 | 0.9860 | 0.9510 |
Solid Content | Fitting Type | CTR | ||||
---|---|---|---|---|---|---|
1:4 | 1:6 | 1:8 | 1:10 | Average | ||
65% | linear | 0.9484 | 0.9382 | 0.9515 | 0.9457 | 0.9460 |
exponential | 0.8269 | 0.8351 | 0.8507 | 0.8219 | 0.8337 | |
68% | linear | 0.9559 | 0.9204 | 0.9060 | 0.9233 | 0.9264 |
exponential | 0.8702 | 0.8169 | 0.8207 | 0.8005 | 0.8271 | |
70% | linear | 0.9480 | 0.9078 | 0.8946 | 0.9267 | 0.9175 |
exponential | 0.8818 | 0.7956 | 0.8288 | 0.8080 | 0.8286 | |
73% | linear | 0.9646 | 0.8723 | 0.8761 | 0.9190 | 0.9080 |
exponential | 0.8983 | 0.7899 | 0.8245 | 0.8149 | 0.8319 |
CTR | Fitting Type | Solid Content | ||||
---|---|---|---|---|---|---|
65% | 68% | 70% | 73% | Average | ||
1:4 | linear | 0.9484 | 0.9539 | 0.9480 | 0.9109 | 0.9403 |
exponential | 0.8269 | 0.8702 | 0.8818 | 0.8189 | 0.8495 | |
1:6 | linear | 0.9382 | 0.9204 | 0.9078 | 0.8723 | 0.9097 |
exponential | 0.8351 | 0.8169 | 0.7956 | 0.7899 | 0.8094 | |
1:8 | linear | 0.9512 | 0.9060 | 0.8946 | 0.8761 | 0.9077 |
exponential | 0.8507 | 0.8207 | 0.8288 | 0.8245 | 0.8311 | |
1:10 | linear | 0.9457 | 0.9233 | 0.9267 | 0.9190 | 0.9287 |
exponential | 0.8219 | 0.8005 | 0.8080 | 0.8149 | 0.8133 |
Group | γ01 (k) | γ02 (k) | γ03 (k) |
---|---|---|---|
1 | 1.000 | 1.000 | 1.000 |
2 | 0.677 | 0.974 | 0.680 |
3 | 0.422 | 0.959 | 0.422 |
4 | 0.333 | 0.949 | 0.333 |
5 | 0.739 | 0.898 | 0.755 |
6 | 0.988 | 0.859 | 0.851 |
7 | 0.578 | 0.821 | 0.535 |
8 | 0.555 | 0.805 | 0.511 |
9 | 0.723 | 0.778 | 0.718 |
10 | 0.715 | 0.736 | 0.947 |
11 | 0.985 | 0.636 | 0.745 |
12 | 0.731 | 0.583 | 0.593 |
13 | 0.620 | 0.545 | 0.651 |
14 | 0.679 | 0.407 | 0.683 |
15 | 0.778 | 0.371 | 0.844 |
16 | 0.868 | 0.333 | 0.749 |
correlational degree | 0.712 | 0.728 | 0.689 |
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Qiu, J.; Yang, L.; Sun, X.; Xing, J.; Li, S. Strength Characteristics and Failure Mechanism of Cemented Super-Fine Unclassified Tailings Backfill. Minerals 2017, 7, 58. https://doi.org/10.3390/min7040058
Qiu J, Yang L, Sun X, Xing J, Li S. Strength Characteristics and Failure Mechanism of Cemented Super-Fine Unclassified Tailings Backfill. Minerals. 2017; 7(4):58. https://doi.org/10.3390/min7040058
Chicago/Turabian StyleQiu, Jingping, Lei Yang, Xiaogang Sun, Jun Xing, and Songbo Li. 2017. "Strength Characteristics and Failure Mechanism of Cemented Super-Fine Unclassified Tailings Backfill" Minerals 7, no. 4: 58. https://doi.org/10.3390/min7040058