Table 1 Standard of classification for assessing the risk of water inrush into tunnel.
Risk level | Risk evaluation classification criteria |
|---|---|
I | Total water inrush rate: < 2000 m3/d, Negligible level of risk, basically no sudden inrush of water hazard accidents |
II | Total water inrush rate: 2000–8000 m3/d, The level of risk is within tolerable limits and usually manifests itself in the form of a small inrush of water, which is unlikely to result in casualties |
III | Total water inrush rate: 8000–14,000 m3/d, Acceptable level of risk, prone to medium-sized inrush water hazard incidents |
IV | Total water inrush rate: 14,000–20,000 m3/d, Higher degree of risk, prone to large-scale inrush water disaster accidents |
V | Total water inrush rate: > 20,000 m3/d, Extremely high level of risk, prone to cause very large inrush water disaster accident |
