Table 5 The groundwater conditions classification (Bieniawski 1989)
Inflow/10 m (lt/minute) | – | < 10 | 10–25 | 25–125 | >  125 |
Pore pressure ratio | 0 | 0–0,1 | 0,1–0,2 | 0,2–0,5 | > 0,5 |
General condition | Dry | Humid | Wet | Dripping | Flowing |
RMRb value | 15 | 10 | 7 | 4 | 0 |