Research Article
Study on the Stability of the Coal Seam Floor above a Confined Aquifer Using the Structural System Reliability Method
Table 4
Calculation results of reliability probability of the water-resistant floor’s stability.
| Cover depth/m | Water pressure/MPa | Coefficient of water inrush/(MPa·m−1) | Parameter | First type of failure mode | Second type of failure mode | Mining failure | Intrusion | Combined mode involving mining and intrusion | Tensile failure | Shear failure |
| 500 | 1.6 | 0.036 | Median safety factor | 9.64961 | 1.70000 | 2.92816 | 2.76584 | 4.75042 | Reliability probability | 0.99991 | 0.99995 | 0.99997 | 0.95363 | 0.98151 | Reliability probability of the system | 0.95259 |
| 520 | 1.8 | 0.040 | Median safety factor | 8.92160 | 1.7000 | 2.87671 | 2.49447 | 4.17738 | Reliability probability | 0.99986 | 0.99995 | 0.99998 | 0.93592 | 0.97427 | Reliability probability of the system | 0.93549 |
| 540 | 2.0 | 0.044 | Median safety factor | 8.27299 | 1.70000 | 2.82513 | 2.27722 | 3.71882 | Reliability probability | 0.99977 | 0.99995 | 0.99998 | 0.91824 | 0.96530 | Reliability probability of the system | 0.91750 |
| 550 | 2.1 | 0.047 | Median safety factor | 7.97488 | 1.70000 | 2.79933 | 2.18406 | 3.52226 | Reliability probability | 0.99966 | 0.99996 | 0.99998 | 0.90659 | 0.95931 | Reliability probability of the system | 0.90757 |
| 560 | 2.2 | 0.049 | Median safety factor | 7.69261 | 1.70000 | 2.77353 | 2.09933 | 3.34353 | Reliability probability | 0.99975 | 0.99996 | 0.99994 | 0.89746 | 0.95426 | Reliability probability of the system | 0.89656 |
| 570 | 2.3 | 0.051 | Median safety factor | 7.42506 | 1.70000 | 2.74774 | 2.02193 | 3.18032 | Reliability probability | 0.99959 | 0.99997 | 0.99998 | 0.88736 | 0.94869 | Reliability probability of the system | 0.88614 |
| 580 | 2.4 | 0.053 | Median safety factor | 7.17123 | 1.70000 | 2.72199 | 1.95095 | 3.03067 | Reliability probability | 0.99955 | 0.99998 | 0.99994 | 0.87791 | 0.94177 | Reliability probability of the system | 0.87619 |
| 590 | 2.5 | 0.056 | Median safety factor | 6.93020 | 1.70000 | 2.696286 | 1.885618 | 2.8929881 | Reliability probability | 0.99954 | 0.99994 | 0.99994 | 0.86646 | 0.93508 | Reliability probability of the system | 0.86549 |
| 600 | 2.6 | 0.058 | Median safety factor | 6.70112 | 1.70000 | 2.67061 | 1.82528 | 2.76586 | Reliability probability | 0.99941 | 0.99995 | 0.99989 | 0.85676 | 0.92849 | Reliability probability of the system | 0.85634 |
| 610 | 2.7 | 0.060 | Median safety factor | 6.48322 | 1.70000 | 2.64501 | 1.76941 | 2.64812 | Reliability probability | 0.99952 | 0.99994 | 0.99992 | 0.84512 | 0.92143 | Reliability probability of the system | 0.84503 |
| 620 | 2.8 | 0.062 | Median safety factor | 6.27582 | 1.70000 | 2.61951 | 1.71751 | 2.53882 | Reliability probability | 0.99932 | 0.99993 | 0.99992 | 0.83644 | 0.91408 | Reliability probability of the system | 0.83609 |
| 630 | 2.9 | 0.064 | Median safety factor | 6.07823 | 1.70000 | 2.59411 | 1.66907 | 2.43691 | Reliability probability | 0.99919 | 0.99996 | 0.99989 | 0.82507 | 0.90543 | Reliability probability of the system | 0.82411 |
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