Kawasaki s Superior Technology

Slurry feed and discharge pipes
A partition is installed toward the anterior of the front body(in the case of a sealed machine). In the slurry shieldtunneling method, slurry prepared at the ground plant is fed
into the chamber (via the slurry feed line) to counteract theground water pressure, thereby stabilizing the surrounding
soil. Excavated soil is discharged to the ground plant after
being sucked up by a pump installed on the carrier behindthe machine (via the slurry discharge line).

2 2H&V (Horizontal and Vertical)
Shield Machine Drives Forward
Challenging UndergroundConstruction Projects

Cutter head

Teeth bit

Slewing bearing
This bearing transmits
power from thecutter-driving electricmotor to rotate thecutter head.

Commentary by

In the shield tunneling method,
the tunnel wall structures(segments) are built to the rearof the shield machine as it
advances. Shield jacks apply
force to the assembled segments
to push the machine forward.

Articulation jackThe shapes of the face plate and the excavation
cutter bits are designed to accommodate thegeological features of the site and the hardness ofthe soil. The fact that the chips mounted on thecutter are made of carbide is indicative of thechallenges involved in excavating earth with varied
geological features, soil properties, and pressures.
Pre-cutting bit

Shield jackFlexible Joint Mechanism of
the Connecting Pins that
Made Spiraling Possible

Flexible joint
mechanism section

In this rainwater overflow drainage project, the machine to
the right advances upward and to the left, gradually achievinga vertical configuration. Because the machine had to bearticulated at 3.9 degrees and perform three-dimensional
movements, development of a flexible joint mechanism wasessential. The two shield machines, placed in horizontal configuration in the departure shaft, perform spiral excavation
Front body Rear bodyfor about 137 m, then change theirposition to a vertical configuration
Flexible joint mechanism(Interior of the rightand excavate a further 600 m.
machine’s rear body)(cross-section view)

This jack supports excavationof curved tunnels by allowing
the anterior body of themachine to flex.
Leftmachine

Presserplate

Senior Staff Officer (formerly Project Manager)
Section 3, Quality Assurance Department of Quality Assurance Division
Energy System & Plant Engineering Company

Engineering Section 1
Tunneling Equipment Department
Energy System & Plant Engineering Company

ShieldjackRightmachine

Hiroshige Uchida (left)

Akane Fukuoka (right)

Mechanical stopper

Shieldjack

Connecting pin

Presserplate

Connecting pin

Direction ofexcavation→

Most peripheral
pre-cutting bit

Kawasaki Achieves World’s First Spiral
Excavation by H&V Shield Tunneling MethoddSlurry feelinee
charge lin
Slurry dis

Shield machines excavate underground tunnels using rotating cutters located at the frontof these steel units. As a result of impressive technical advancements over the last 170years, very complex projects can now be carried out using two shield machines designed
to work in tandem ― an excavation method called the “H&V Shield Tunneling Method.”

Begun in 2013, a Tokyo Metropolitan Government Sewage Bureau project to constructpipelines for draining rainwater overflow from the Tachiaigawa River (in Shinagawa,Tokyo) to the Keihin Canal saw the world’s first implementation of this H&V Shield Tunneling “spiral excavation” method. In this type of excavation, two shield machines are
initially configured either side-by-side (horizontal configuration) or one on top of theother (vertical configuration). As they move forward, however, they spiral to alternate
from a horizontal to a vertical configuration or vice versa. In the rainwater overflow
drainage project, the machines excavated with their positions changing from the horizon-

Working deck

Each shield machineis custom-made,tailored to the site’sgeographical features
and thestructure’s purpose

soil
atedvacEx

Cutter-driving electric motor
The shield machine is equipped with six
reduction gear motors to drive the cutter,
which rotates at 0.82 rpm.

tal to the vertical settings.

This area within the machine
permits workers to performsegment assembly and othertasks. Even when themachine is spiraling, the angleof the working space floorchanges (up to 90 degrees) sothat the deck remains level.

Each machine is 5.85 m in diameter and weighs about 400 t. Amazingly enough, thesegigantic machines were able to follow the meandering of the river as they excavated,maintaining an extremely narrow, 9-cm space between them. Key to this success was
the “flexible joint mechanism” of the pins. It enables each machine to move helically■ Project to Accommodate Challenging Urban Restrictions

around an axis to achieve spiral excavation, while the two machines stay connected.
The previous connection was a fixed one, allowing the rear bodies to move only in

Revetment pilingsof the canalthe same direction.
To date, Kawasaki has delivered 1,400 units of shield machines for both domestic andRight shield machineinternational tunneling projects. Some of them were used in constructing the Channel
Departure
shaft

Tunnel beneath the Strait of Dover between the UK and France, which the American
Society of Civil Engineers recognizes as one of the top 10 civil engineering achievementsof the 20th century in the railway category. Kawasaki’s technological prowess con-Flexible joint
mechanism section

tributed to making possible another “world’s first”.

Underground
Left shield machine

10Scope 123

The site for constructing two 5-m diameter pipelines under theTachiaigawa River for draining excess rainwater is approximately
778-m long. The pipelines will take up rainwater overflow toprevent flooding in the vicinity and contamination from sewage
coming from the “combined sewage system.” The excavation
under the river first required the shield machines to go under therevetment pilings near the departure shaft. It also necessitated thatthe machines maintain an excavation path of less than 8 m to staywithin the river’s width. It was a challenging project with many
restrictions to deal with. However, thanks to Kawasaki’s shieldmachines which are capable of spiraling, coupled with robust
project management by Shimizu Corporation, the excavation,
which began in March 2018, was completed in July 2019.

(Curve radius)

Excavation route has consecutive tight curves measuring R=55 m
Arrival shaft

Tachiaigawa Stationon the Keikyu Line
Verticalconfig.
R=55 m

Verticalconfig.
R=55 m

Verticalconfig.
R=55 mKatsushima Canal

Right machine
Verticalconfig.
R=55 mTachiaigawa River

Verticalconfig.
R=55 m

Verticalconfig.
R=80 mSpiraling
section137 m

Horizontal
config.
R=50 mLeft machine

Departure shaft

778 m
Scope 123

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