@This method starts an enlarged shield from the starting base at a
given point in a shield driven tunnel and excavates the tunnel longitudinally
to enlarge the cross section in the tunnel.
| 1. |
Cross section can be enlarged for
a desired length according to the use of space.
|
| 2. |
Circular cross section created after
enlargement ensures structural stability.
|
| 3. |
Eccentric enlargement of cross section
is possible in all directions.
|
| 4. |
The method offers even greater economy
and shorter construction period in tunneling at greater depths.
|
| 5. |
Work is carried out exclusively in
the tunnel with no adverse effects on surface traffic or the
environment. |
 @One
of three construction methods can be selected according to the length
of the tunnel to be enlarged.
| Type 1: |
Combination of circumferential
shield tunneling system and enlargement shield tunneling system
|
| Type 2: |
Combination of circumferential shield tunneling
system and enlargement excavation system
|
| Type 3: |
Circumferential shield tunneling system |
Circumferential shield machine |
 |
| Enlargement shield machine |
Enlargement slurry shield machine |
|
|
1. Excavation by a circumferential shield machine
(construction of the base for starting an enlargement shield machine)
£zoom
2. Assembly of an enlargement shield machine
£zoom
3. Tunneling by the enlargement shield machine
£zoom
| |
| Use |
Outer diameter (mm) |
Length (m) |
| Primary segment |
Enlarged segment |
Underground
cable tunnel |
6,600
|
7,800
|
24.1
|
| Utility tunnel |
6,600 |
9,200 |
29.5 |
| Sewer tunnel |
6,000 |
8,709 |
11.3 |
| 2,000 |
3,150 |
2.6 |
|
|
