2.Jacket Materials
Geo's most important products are jackets used for reinforcing.
| 1) |
Hose-like jacket: Seamless woven jacket, 200 mm in diameter,
made from the same material used for fire hoses.
Characterized by having both high yield strength and for being
light weight. |
| 2) |
Large jacket: Seamless woven jacket up to 2000 mm in diameter. |
| 3) |
Pipe jacket: Woven jacket combining high compressive yield
strength, filtering capability, flexibility and the rigidity
necessary for maintaining a round cross section (see Fig. 1). |
| 4) |
3D jacket: Unique seamless woven jacket with a diameter varies
along the length of the jacket (see Fig. 2). Diametric variation
can be up to 6X and it can be used to form varied shapes such
as bumps or tank shapes. |
| 5) |
Cross jacket: Two hose jackets, each containing a ‘bump' section,
joined at right angles to form a cross configuration with full
structural integrity. |
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Figure 1 Pipe jacket |
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Figure 2 Large 3D jacket |
3.Construction Methods
using Jackets
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| Figure 3 |
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Experimental installation to reduce water volume with Rogepack R |
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| Figure 4 |
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Tyuramizu (slow sand filter) |
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These construction methods take full advantage of the tensile
strength of the fiber for various applications of the tubular jackets.
The materials and methods are described below.
(1) Handling of muddy soil and water (Rogepack,
Tyuramizu)
Rogepack S, E is a bag material developed in collaboration
with P.S. Mitsubishi Construction Co., Ltd. and Ashimori Industry
Co., Ltd. It is the material used for the “ecotube”, a recycling
system for both solidifying and facilitating the disposal of surplus
soil from construction sites. The product was jointly developed
by the Public Works Research Institute (formerly part of the then-Ministry
of Construction; now renamed the ‘Incorporated Administrative Agency
Public Works Research Institute'), the Public Works Research Center,
and nine commercial enterprises. The ecotube system reduces the
volume of soft ground with high water content such as substrates
extracted from riverbeds, behind dam walls, or in reservoirs. The
water is removed without using chemicals such as hardening agents
and the resulting soil can be used as banking material at other
construction sites. The High Grade Soil Study Consortium, which
was formed by the Public Works Research Institute, the Public Works
Research Center and 37 enterprises, are currently involved in a
program directed at promoting the use of this system.
Rogepack R (Fig. 3) is a material used for consolidating
and treating mud extracted from the bottom of reservoirs
and oxidation ponds at water purification plants. In order to reduce
transportation costs, water can be removed from the mud on site
before it is transported to a treatment facility.
Tyuramizu (Fig. 4), a slow sand filter used as a pipe
jacket for drains, has been developed as a means of preventing
the erosion of red soil in Okinawa. Filtration of the muddy water
through the sand is periodically interrupted to back-wash the pipe
jacket to remove sand and contaminants from the jacket openings.
The solids thus removed are collected by Rogepack located
underneath. This system is capable of extended use and appears
to have considerable potential for simple drain water processing
at industrial sites. A prototype of this pipe jacket system
has been installed at a sedimentation basin in Ishigakijima, Okinawa.
The system has received excellent performance evaluations to date.
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| Figure 5 |
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Verification test
for Palace Sheet |
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(2) Bump Anchor (Bump Jacket)
Bump anchor are 3D jacket that have several
bumps in the longitudinal direction (bump jacket) and
are used as anchoring members, holding anchors or lock bolts. They
offer great pull-through resistance for use on silt or clay foundations
or other locations where mortar reinforcement is not practical.
(3) Palace Sheet (Cross Jacket)
Palace Sheet is a system jointly developed by Kajima
Corporation and Ashimori Industry Co. Ltd for improving the surfaces
of construction locations with weak subgrades. It is intended for
use while building roads and other structures through reclaimed
land, marshy areas and other such locations. The load is dispersed
by the lattice structure formed by cross jackets filled with mortar,
which act to decrease the likelihood of the sheet tearing under
the loads and movement of heavy equipment. Tests to verify their
properties and characteristics have already been conducted by Chouhou
Construction Co., Ltd. (Nagano Prefecture, Iida City) together
with Ashimori Industry Co. Ltd also in Nagano Pref. (see Fig. 5).
Another pilot project by Yamadagumi (Aichi Prefecture, Nagoya City)
in Gifu Prefecture is being conducted to improve the subgrade without
damaging a river environment.
(4)SZ Cuttable Construction Materials (SZ Pile, SZ
Segment)
SZ CuttableConstruction Materials
were jointly developed by Kajima Corporation and
Ashimori Industry Co. Ltd. They are a new cuttable construction
material designed for use in tunnels where they can be cut by shield
machine. Ashimori's proven method for replacing underground piping,
the Paltem
SZ Construction Method, employs a process that uses a special
FRP. Not only can this be employed for shaft walls,
but it can also be used for curved components such as shield segments.
At Ashimori, we look forward to applying the expertise
we have gained over our many years of service in the fiber industry
toward fulfilling the diverse needs of the construction industry
for jackets and other fiber technologies. We ask the members of
IGS for their advice and suggestions.
 Newsletter of Japan chapter of International Geosynthetics Society, November
2004
Using Jackets in Construction |
