|
| Indicator | Criteria |
| Very weak | Weak | Moderate | Strong | Very strong |
|
|
[C11] average annual rainfall (mm) | <600 | 600~800 | 800~1000 | 1000~1600 | >1600 |
|
[C12] average annual evaporation (mm) | >800 | 600~800 | 500~600 | 400~500 | <400 |
|
[C13] area of catchment zone (km2) | <5 | 5~10 | 10~30 | 30~50 | >50 |
|
[C14] coefficient of rainfall infiltration | <0.05 | 0.05~0.15 | 0.15~0.30 | 0.30~0.50 | >0.50 |
|
[C15] spatial relationship between the tunnel and geomorphology | Other (such as flat, protruding) | Flat and basin-shaped | Angular space and river crossing | Side below the valley and river crossing | Right below the valley and river crossing |
|
[C16] capacities of reservoirs and lakes on the ground (m3) | <1 | 1~10 | 10~50 | 50~300 | >300 |
|
[C17] flow of surface rivers (m3/s) | <0.1 | 0.1~0.5 | 0.5~2.0 | 2.0~10.0 | >10.0 |
|
[C21] carbonate rocks exposure ratio (%) | <30 | 30~50 | 50~70 | 70~90 | >90 |
|
[C22] water yield property of aquifers | <5 | 5~10 | 10~15 | 15~20 | >20 |
|
[C23] water pressure on the tunnel (Mpa) | <0.5 | 0.5~1.0 | 1.0~3.0 | 3.0~5.0 | >5.0 |
|
[C24] development of folds | No folds | Folds with undeveloped fissure | Folds with moderately developed fissure | Folds with developed fissure | Folds with developed faults |
|
[C25] development of fracture zones | Rarely developed | Poorly developed | Moderately developed | Developed | Well developed |
|
[C26] formation lithology | Mudstone, shale, or clay | Sandstone or fine sandstone | Granite or igneous rock | Metamorphic rock | Soluble rocks including limestone, dolomite, and so forth |
|
[C27] location of tunnel in horizontal and vertical hydrodynamic zoning of groundwater | Recharge area in horizontal and unsaturated zone in vertical zoning | Recharge area in horizontal and seasonal fluctuation zone in vertical zoning | Runoff area in horizontal and shallow saturation zone or deep circulation zone in vertical zoning | Runoff area in horizontal and stressful saturation zone in vertical zoning | Discharge area in horizontal zoning |
|
[C31] length of tunnel (km) | <1.0 | 1.0~3.0 | 3.0~10.0 | 10.0~30.0 | >30.0 |
|
[C32] area of disturbed range (m2) | <50 | 50~120 | 120~250 | 250~350 | >350 |
|
[C33] construction method | Tunnel boring machine method | New Austrian Tunneling Method | Partial excavation using drilling and blasting method | Benching tunneling using drilling and blasting method | Full face excavation using drilling and blasting method |
|
[C34] burial depth of tunnel (m) | Extremely bad for water inflow | Bad for water inflow | Moderate for water inflow | Good for water inflow | Extremely good for water inflow |
|
[C35] measures for prevention of groundwater flowing into tunnel | Composite lining and pregrouting | Composite lining and exterior waterproof (or postgrouting) | Composite lining | Structural self-waterproof | Drainage |
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