Research Article
Risk Evaluation Model of Highway Tunnel Portal Construction Based on BP Fuzzy Neural Network
Table 9
The model parameters after optimization.
| | Formation or structure | Elastic modulus E (GPa) | Poisson’s ratio (μ) | Bulk density (kN/m3) | Cohesion (kPa) | Internal friction angle (°) |
| | Fully weathered gneiss | 0.2 | 0.4 | 18 | 50 | 28 | | Strong weathering gneiss | 0.5 | 0.35 | 20 | 200 | 32 | | Weathering gneiss | 1 | 0.3 | 22 | 320 | 35 |
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