Pneumatic
caisson
technology
Shield tunneling
technology
Port and
harbor technology
Urban rejuvenation
/green technology
Outline of pneumatic caisson
Developing Parallel Link Excavation (DPLEX) shield method
Dolphin dock construction method
Reinforce and Repair by Compound Closingwall (RECC) construction method

Civil Engineering Business: Developing Parallel Link Excavation (DPLEX) Shield Method

The shield method for building tunnels with arbitrary cut faces

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Outline of the construction method

With the developing parallel link excavation (DPLEX) shield method, cutters are rotated by the parallel link mechanism mounted on multiple rotating shafts to excavate cross-sectional surfaces that are nearly the same figure as the cutter shape; therefore, it allows for the construction of tunnels with arbitrary cross-sectional surfaces other than circular shapes, such as oval and horseshoe shapes. Our employees took on the challenge of developing the world’s first square shield and demonstrated the outstanding achievement both internally and externally. As a result, the DPLEX shield method received the Technological Development Award by Japan Society of Civil Engineers in fiscal 1996.

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Principle of excavation Example cross-sectional surfaces

Characteristics of the construction
method

Excavation of arbitrary cross-sectional surfaces is possible.

By changing the shape of the cutter frame in case the upper and lower sides of tunnel are restricted by an underground structure or the site width is narrow, it is possible to choose an arbitrary cross-sectional shape suitable for the purpose, such as circular, rectangular, oval, and horseshoe shapes. Therefore, it is applicable even though there are limiting underground conditions, and it is able to use the underground effectively and economically.

Cutter torque can be set to low.

With the small rolling radius of the cutter, the torque of the equipped cutter can be approximately 1/3 compared to the single-shaft mud pressurization shield, allowing for downsizing of the cutter driving device and reduction of output, which makes this method best suited for the shield of large-cross sectional surfaces.

Long-distance work is available without replacing the bits.

Thanks to the small rolling radius of the cutter and the short sliding distance of the bit, all bits are worn equally and by only a limited degree. The amount of wear can be approximately 1/3 compared to the single-shaft mud pressurization shield; therefore, the work distance can be increased as much as about three times without replacing the bits.

Easy to inject inside the machine.

By dispersing multiple shafts for driving the cutter, a large space can be ensured inside the machine; therefore, equipment for improving the ground, as well as the manhole, can be properly allocated. This makes it easy to perform ground improvement and remove obstacles.

Transport, assembly, and disassembly are easy.

Since multiple cutter driving sections are designed as compact units, they are easy to transport, assemble, and disassemble, and the larger the cross-sectional surfaces, the more powerful the advantage becomes. Moreover, since equipment is designed as a small unit, and the work process is shortened, costs for the shield device, as well as work costs, can be reduced.

Our Works

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    Work name
    Narashino City, Kikudagawa No.2 Trunk Sewer
    Construciton Work 18
    Client
    Japan Sewage Works Agency
    Construction period
    H6.2 to H8.9
    Work location
    Chiba Prefecture
    Application
    Sewerage
    Shape
    Arc-like rectangle
    Outer diameter of the machine (m)
    H3.98×W4.38
    Work extension (m)
    392 417
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    Work name
    MM, Honmachi Shield T Work
    Client
    Japan Railway Construction Public Corporation
    Construction period
    H10.3 to H13.2
    Work location
    Kanagawa Prefecture
    Application
    Subway
    Shape
    Circular
    Outer diameter of the machine (m)
    φ7.15
    Work extension (m)
    452 432
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    Work name
    Installation Work for Sewage Pipe of Doi River Rainwater Pipe
    (2nd section)
    Client
    Sakai City
    Construction period
    H11.1 to H13.3
    Work location
    Osaka Prefecture
    Application
    Sewerage
    Shape
    Circular (Parent and Child)
    Outer diameter of the machine (m)
    Parent φ3.93 Child φ2.14
    Work extension (m)
    Parent machine 1,026 Child machine 751
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    Work name
    Teito Rapid Transit Authority Route 11 Honjo Section
    Client
    Teito Rapid Transit Authority
    Construction period
    March 1999 to April 2001
    Work location
    the Tokyo Metropolitan Government
    Application
    Subway
    Shape
    Circular
    Outer diameter of the machine (m)
    φ9.60
    Work extension (m)
    907
See here for our work
in the Civil Engineering Business
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