Influence of Spatial Relationships between Key Strata on the Height of Mining-Induced Fracture Zone: A Case Study of Thick Coal Seam Mining
Abstract
:1. Introduction
2. Development of Fractures in Overburden Induced by Thick Seam Mining
2.1. Geological Conditions
2.2. Field Measurements of the Height of CFZ
3. The Mechanism by Which the KS Influenced the CFZ’s Height
3.1. Influence of KS on the CFZ’s Height
3.2. Spatial Relationships between KS Required for Their Fracturing
4. Discussion
5. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
Abbreviations
CFZ | Conductive Fracture Zone |
KS | Key Strata |
HoL | Height of Linkage |
PKS | Primary Key Stratum |
SKS | Secondary Key Strata |
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KS No. | Rock Type | Thickness (m) | Tensile Strength (MPa) | Elastic Modulus (GPa) | Wmax (mm) |
---|---|---|---|---|---|
SKS 1 | Mudstone | 10.05 | 2.2 | 17.0 | 5.9 |
SKS 2 | Fine sandstone | 7.95 | 6.0 | 45.6 | 2.6 |
SKS 3 | Fine sandstone | 11.45 | 6.0 | 45.6 | 3.1 |
PKS | Siltstone | 11.16 | 5.2 | 40.0 | 1.4 |
Model Type | Model a | Model b | Model c | Model d |
---|---|---|---|---|
Illustration | | | | |
Spatial relationships between adjacent KS | The height difference between SKS 2 and SKS 1 is greater than the HoL between them. | The height difference between SKS 2 and SKS 1 is smaller than the HoL between them, while the height difference between SKS 3 and SKS 2 is greater than the corresponding HoL. | The height difference between SKS 3 and SKS 2 is smaller than the HoL between them, while the height difference between PKS and SKS 3 exceeds the corresponding HoL. | The height difference between PKS and SKS 3 is less than the HoL between them. |
State of KS | SKS 2 is unfractured. | SKS 2 is fractured while SKS 3 is unfractured | SKS 3 is fractured while PKS is unfractured | PKS is fractured |
The height of CFZ | Fractures terminate at the bottom of SKS 2. | Fractures propagate through SKS 2 and terminate at the bottom of SKS 3. | Fractures run through SKS 3 and terminate at the bottom of PKS. | Fractures extend through all key strata and reach the surface |
Adjacent KS | Height Difference between Them (m) | HoL between Them (m) |
---|---|---|
SKS 1–SKS 2 | 52.95 | 61.25 |
SKS 2–SKS 3 | 78.55 | 59.32 |
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Li, P.; Wang, X.; Cao, W.; Zhang, D.; Qin, D.; Wang, H. Influence of Spatial Relationships between Key Strata on the Height of Mining-Induced Fracture Zone: A Case Study of Thick Coal Seam Mining. Energies 2018, 11, 102. https://doi.org/10.3390/en11010102
Li P, Wang X, Cao W, Zhang D, Qin D, Wang H. Influence of Spatial Relationships between Key Strata on the Height of Mining-Induced Fracture Zone: A Case Study of Thick Coal Seam Mining. Energies. 2018; 11(1):102. https://doi.org/10.3390/en11010102
Chicago/Turabian StyleLi, Peng, Xufeng Wang, Wenhao Cao, Dongsheng Zhang, Dongdong Qin, and Hongzhi Wang. 2018. "Influence of Spatial Relationships between Key Strata on the Height of Mining-Induced Fracture Zone: A Case Study of Thick Coal Seam Mining" Energies 11, no. 1: 102. https://doi.org/10.3390/en11010102