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/mWater pressure/MPaCoefficient of water inrush/(MPa·m−1)ParameterFirst type of failure modeSecond type of failure mode
Mining failureIntrusionCombined mode involving mining and intrusionTensile failureShear failure

5001.60.036Median safety factor9.649611.700002.928162.765844.75042
Reliability probability0.999910.999950.999970.953630.98151
Reliability probability of the system0.95259

5201.80.040Median safety factor8.921601.70002.876712.494474.17738
Reliability probability0.999860.999950.999980.935920.97427
Reliability probability of the system0.93549

5402.00.044Median safety factor8.272991.700002.825132.277223.71882
Reliability probability0.999770.999950.999980.918240.96530
Reliability probability of the system0.91750

5502.10.047Median safety factor7.974881.700002.799332.184063.52226
Reliability probability0.999660.999960.999980.906590.95931
Reliability probability of the system0.90757

5602.20.049Median safety factor7.692611.700002.773532.099333.34353
Reliability probability0.999750.999960.999940.897460.95426
Reliability probability of the system0.89656

5702.30.051Median safety factor7.425061.700002.747742.021933.18032
Reliability probability0.999590.999970.999980.887360.94869
Reliability probability of the system0.88614

5802.40.053Median safety factor7.171231.700002.721991.950953.03067
Reliability probability0.999550.999980.999940.877910.94177
Reliability probability of the system0.87619

5902.50.056Median safety factor6.930201.700002.6962861.8856182.8929881
Reliability probability0.999540.999940.999940.866460.93508
Reliability probability of the system0.86549

6002.60.058Median safety factor6.701121.700002.670611.825282.76586
Reliability probability0.999410.999950.999890.856760.92849
Reliability probability of the system0.85634

6102.70.060Median safety factor6.483221.700002.645011.769412.64812
Reliability probability0.999520.999940.999920.845120.92143
Reliability probability of the system0.84503

6202.80.062Median safety factor6.275821.700002.619511.717512.53882
Reliability probability0.999320.999930.999920.836440.91408
Reliability probability of the system0.83609

6302.90.064Median safety factor6.078231.700002.594111.669072.43691
Reliability probability0.999190.999960.999890.825070.90543
Reliability probability of the system0.82411