| 1. |
Excavation in high-water-pressure
gravel layer at great depths using muddy soil pressure |
Safe excavation is ensured by controlling high water pressure and
preventing blows or face collapse.
| 2. |
Adaptability to the soil or groundwater
condition |
Adjusting the volume of chemical additives or changing
to an ordinary muddy soil shield method is easy.
| 3. |
Improvement of excavated soil |
Excavated soil can be improved to make a soil without
fluidity, which can be transported out of the tunnel as an ordinary
excavated soil.
| 4. |
Use of environmental-friendly safe
material |
Main chemical agent and assistant are safe to
both humans and animals, and neutralize the improved soil.
|
|
An additive and the main chemical agent are mixed with the excavated
soil in the chamber. Then, the assistant is injected into the screw
conveyor to create a cut-off plug from improved soil. This enables
safe and accurate excavation in water-bearing gravelly soil under
high water pressure while controlling face pressure and preventing
face collapse due to blow and other soil disturbances.
|
