A Method for Dividing Rockburst Risk Zones—A Case Study of the Hegang Mining Area in China
Abstract
:1. Introduction
2. Overview of Rockbursts in the Hegang Mining Area
3. Distribution of the In-Situ Stress in the Hegang Mining Area
3.1. In-Situ Stress Measurement
- Representativeness: The test locations should represent the general characteristics of the regional stress field.
- Stability of the rock layers: The test locations should be chosen in stable rock layers with homogeneous and intact rocks.
- Influence of geological structures: The test locations should not be strongly affected by geological structures and should be kept away from areas with complex geological structures.
- Avoidance of mining impact: The test locations should not be located in areas with a dense distribution of tunnels and chambers and should be far from mining and excavation faces to minimize the influence of errors caused by mining activities.
- Construction feasibility: The test locations should be chosen at positions favorable for in-situ stress measurement, considering factors such as the available construction space, water, and electricity, thereby ensuring that they do not conflict with other processes in coal mining production.
3.2. Inversion of the In-Situ Stress Field in the Hegang Mining Area
4. Criteria for Dividing Rockburst Risk Zones
- (1)
- For coal seams with a weak tendency to suffer rockburst, the criteria for dividing rockburst risk zones can be expressed as:
- (2)
- Because coal seams with a strong tendency to suffer rockburst are easily affected by other factors that cause rockburst, there is no safe zone. The corresponding division criteria can be defined as follows:
5. Division of the Hegang Mining Area into Rockburst Risk Zones
6. Discussion
7. Conclusions
- (1)
- To enable the inversion of the in-situ stress, first, representative measurement points were selected in the Hegang mining area; second, numerical models were established based on representative exploration lines in the region; third, the model loads were calculated based on the measured in-situ stress results; and finally, the maximum horizontal principal stress values at the main mining level were extracted through an interpolation method to generate a maximum horizontal-principal-stress contour map for the main mining level. By comparing the measured and simulated data, the relative error distribution range of the maximum horizontal principal stress was found to be 0.44 to 50.77%, with an average error of 17%. Thus, the numerical simulation results for the in-situ stress indicated a certain degree of rationality.
- (2)
- Based on energy theory, the minimum energy principle, field microseismic monitoring, and early warning data, we proposed criteria for the division of the Hegang mining area into rockburst risk zones and calculated the total stored energy in the coal–rock mass at mining elevations of −330 m and −450 m based on the inversion results for the in-situ stress field in the Hegang mining area. Then, we adopted coal seam #3 as an example to illustrate the division of the Hegang mining area into rockburst risk zones based on the division criteria proposed herein and generated rockburst risk zoning maps accordingly. When the five rockburst events that occurred in coal seam #3 in the Hegang mining area were marked on the risk zoning map, it was found that their locations coincided with the threatened zone.
- (3)
- The division method for rockburst risk zones proposed in this paper accounts for both the coal seam characteristics and the in-situ stress conditions, resulting in more accurate and meaningful prediction results, especially for rockburst prediction before coal seam mining begins. Therefore, coal mines can take preventive measures based on these evaluation results to prevent the occurrence of rockburst disasters.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Rock Stratum | Thickness/m | Histogram | Lithology Description |
---|---|---|---|
sandstone | 80 | Mainly fine grey sandstone, intercalated thin conglomerate and black–grey siltstone | |
#3 coal | 3.5 | Coal | |
sandstone | 50 | Fine siltstone interbedding, grey horizontal bedding | |
#7 coal | 3.0 | Coal | |
fine sandstone | 40.0 | Fine sandstone, light grey | |
#8 coal | 1.43 | Coal | |
medium-grained sandstone | 8.0 | Medium-grained sandstone with fine siltstone | |
#9 coal | 0.8 | Low-quality coal | |
sandstone | 25 | Mainly fine sandstone with medium-grained sandstone in the upper part, coarse- to medium-grained sandstone with fine sandstone in the lower part | |
#10 coal | 0.6 | Coal; poor quality at the top, good quality at the bottom | |
sandstone | 18 | Fine sandstone in the upper and lower parts and medium sandstone in the middle part, light grey–white grey | |
#11 coal | 1 | Coal, containing layers of rock | |
sandstone | 23 | Medium-grained sandstone and fine sandstone, with a thin siltstone layer | |
#12 and #13 coal | 6 | Coal, possible ash siltstone in the middle | |
sandstone | 20 | Coarse, medium-grained sandstone with fine siltstone; grey to light grey | |
#15-1 coal | 9 | Coal; coal–shale interbed at the top, with several intercalated layers of rock | |
fine sandstone | 55 | Fine sandstone | |
#15-2 coal | 3.5 | Good-quality, hard coal | |
sandstone | 2 | Siltstone and medium sandstone, all grey–white | |
#18-1 coal | 3.6 | Coal; the quality of the lower part is good, with a thin layer of fine sandstone, brown and contains water | |
sandstone | 38 | Fine and medium sandstone, with siltstone | |
#18-2 coal | 4.55 | Coal | |
fine sandstone | 25 | Fine sandstone | |
#18-2-2 coal | 1.1 | Coal | |
sandstone | 6 | Siltstone, fine sandstone, sandstone, coarse sandstone; mostly grey | |
#18-3 coal | 1.5 | Coal, semi-bright, hard | |
sandstone | 25 | Siltstone in the upper part and fine sandstone in the lower part | |
#21 coal | 1.5 | Coal, semi-bright, brown locally | |
sandstone | 20 | Fine sandstone in the upper and lower parts and coarse sandstone in the middle, with poor sorting and local gravel | |
#22 coal | 6.4 | Coal with two layers of fine sandstone and rock | |
sandstone | 40 | Fine siltstone intertexture | |
#27 coal | 3.3 | Good-quality coal containing beaded inclusion stones | |
sandstone | 22 | Fine siltstone interbedded | |
#29-1 coal | 0.6 | Coal | |
fine sandstone | 8 | Fine sandstone | |
#29-2 coal | 2.03 | Coal | |
fine sandstone | 5 | Fine sandstone | |
#29-3 coal | 2.68 | Low-quality coal | |
sandstone | 15 | Fine sandstone, medium sandstone | |
#30 coal | 5.6 | Coal, containing several layers of rock | |
sandstone | 30 | Fine, silty sandstone in the upper part; coarse, coarse sandstone in the lower part, with glutenite | |
#31 coal | 1.7 | Low-quality coal | |
sandstone | 35 | Medium sandstone, coarse sandstone, fine sandstone | |
#32 coal | 1.6 | Low-quality coal | |
sandstone | 28 | Fine sandstone, gravel, coarse sandstone, fine sandstone, conglomerate | |
#33 coal | 1.69 | Low-quality coal | |
sandstone | 30 | Fine sandstone, medium sandstone, tuffaceous siltstone, medium sandstone | |
#34 coal | 2 | Low-quality coal | |
sandstone | 30 | Tuffaceous siltstone, fine sandstone, coarse sandstone, tuffaceous siltstone | |
#35 coal | 0.7 | Low-quality coal | |
fine sandstone | 35 | Mainly fine sandstone with some tuff mudstone | |
#36 coal | 0.8 | Low-quality coal | |
siltstone | 035 | Tuffaceous siltstone |
No. | Lithology | Bulk Density (kg/m3) | Bulk Modulus (GPa) | Shear Modulus (GPa) | Tensile Strength (MPa) | Cohesive Force (MPa) | Internal Friction Angle (deg) |
---|---|---|---|---|---|---|---|
1 | Sandstone | 2630 | 2.19 | 1.87 | 0.01 | 1.211 | 36 |
2 | Coal Seam | 1380 | 1.05 | 0.95 | 0.015 | 0.188 | 42 |
3 | Fault | 1302 | 0.036 | 0.066 | 0.001 | 0.007 | 30 |
Prospecting Line | Average Elevation (m) | Upper Boundary Burial Depth (m) | Average Bulk Density (N·m−3) | Upper Boundary Load (MPa) | Horizontal Load Gradient Equation (m) |
---|---|---|---|---|---|
a | 254 | 304 | 0.028 | 8.7 | 2.82 + 0.044 h |
b | 259 | 309 | 0.028 | 8.8 | 2.82 + 0.044 h |
c | 266 | 316 | 0.030 | 9.4 | 31.1 |
d | 285 | 335 | 0.026 | 8.8 | 12.27 + 0.033 h |
e | 290 | 340 | 0.027 | 9.2 | 11.94 + 0.029 h |
f | 330 | 380 | 0.027 | 10.2 | 1.31 + 0.048 h |
g | 310 | 360 | 0.023 | 8.5 | 20.3 |
h | 330 | 380 | 0.024 | 9.1 | 8.82 + 0.018 h |
Measurement Point | ||||||
---|---|---|---|---|---|---|
Measured Value (MPa) | Calculated Value (MPa) | Relative Error | Measured Value (MPa) | Calculated Value (MPa) | Relative Error | |
JD#1 | 33.42 | 23 | 31.18% | 21.16 | 16 | 24.39% |
JD#2 | 22.87 | 23 | 0.57% | 13.2 | 13 | 1.52% |
JD#3 | 32.5 | 16 | 50.77% | 17.49 | 16 | 8.52% |
XA#1 | 30.1 | 25 | 16.94% | 23.61 | 16 | 32.23% |
XA#2 | 32.72 | 26 | 20.54% | 24.03 | 16 | 33.42% |
XA#3 | 30.48 | 16 | 47.51% | 13.95 | 14 | 0.36% |
FL#1 | 35.9 | 28 | 22.01% | 21.67 | 18 | 16.94% |
FL#2 | 39.2 | 28 | 28.57% | 18.69 | 20 | 7.01% |
FL#3 | 41.2 | 30 | 27.18% | 22.37 | 20 | 10.59% |
XL#1 | 39.64 | 36 | 9.18% | 26.14 | 22 | 15.84% |
XL#2 | 39.79 | 32 | 19.58% | 27.93 | 22 | 21.23% |
XL#3 | 35.49 | 26 | 26.74% | 20.98 | 18 | 14.20% |
NS#1 | 27.878 | 28 | 0.44% | 14.223 | 14 | 1.57% |
NS#2 | 25.729 | 26 | 1.05% | 14.438 | 14 | 3.03% |
NS#3 | 23.892 | 24 | 0.45% | 12.946 | 12 | 7.31% |
NS#4 | 31.813 | 25 | 21.42% | 17.258 | 16 | 7.29% |
NS#5 | 25.576 | 26 | 1.66% | 13.435 | 13 | 3.24% |
YX#1 | 21.7 | 26 | 19.82% | 13.6 | 14 | 2.94% |
YX#2 | 19.0 | 12 | 36.84% | 13.4 | 16 | 19.40% |
YX#3 | 20.3 | 20 | 1.48% | 12.0 | 14 | 16.67% |
XS#1 | 17.9 | 18 | 0.56% | 11.7 | 12 | 2.56% |
XS#2 | 21.6 | 18 | 16.67% | 15.76 | 14 | 11.17% |
XS#3 | 18.6 | 18 | 3.23% | 11.10 | 12 | 8.11% |
XS#4 | 14.7 | 14 | 4.76% | 11.11 | 12 | 8.01% |
Coal Seam | Compressive Strength (MPa) | Elastic Modulus (GPa) | Minimum Energy (J) |
---|---|---|---|
#3 | 13.511 | 9.00 | 10,141.51 |
Yixin #3 | 14.582 | 9.00 | 11,813.04 |
Coal Seam | Index | Measurement Results | ||||
---|---|---|---|---|---|---|
DT | WET | KE | Rc | Classification | Name | |
Yinxin #3 | 1356 | 2.925 | 6.684 | 14.582 | III | strong tendency |
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Pang, J.; Yang, X.; Yang, S.; He, Y.; Xie, J.; Han, Q. A Method for Dividing Rockburst Risk Zones—A Case Study of the Hegang Mining Area in China. Sustainability 2023, 15, 14808. https://doi.org/10.3390/su152014808
Pang J, Yang X, Yang S, He Y, Xie J, Han Q. A Method for Dividing Rockburst Risk Zones—A Case Study of the Hegang Mining Area in China. Sustainability. 2023; 15(20):14808. https://doi.org/10.3390/su152014808
Chicago/Turabian StylePang, Jiewen, Xiaojie Yang, Shaoqiang Yang, Yongliang He, Jianlin Xie, and Qiaoyun Han. 2023. "A Method for Dividing Rockburst Risk Zones—A Case Study of the Hegang Mining Area in China" Sustainability 15, no. 20: 14808. https://doi.org/10.3390/su152014808