Note: Descriptions are shown in the official language in which they were submitted.
CA 02518571 2005-09-08
SANDBAG RETAINING WALLS ADAPTED
FOR PLANT GROWTH
Technical Field
The invention pertains to sandbag wall systems for use in erosion
control, flood protection, coastal protection, slope stabilization and similar
applications, and to improved bags and walls.
Background of the Invention
In the art of erosion control, flood protection, coastal protection,
slope stabilization and the like, it is known to build strong and effective
retaining walls made with sandbags, preferably using interconnecting
members to connect the bags together and stabilize the wall. See, for
example, International patent publication WO 00/61880 (Kim) dated
October 19, 2000. It is often desirable to grow vegetation on the face of a
sandbag retaining wall, both for aesthetic reasons and to provide additional
protection to the wall face. This can be done by using soil mixed with
grass seed or other plant seeds as a fill material. The bags are made of
geotextile or other material which permits plants to grow out through the
bag walls. As the seeds in the filled bags germinate and plants grow out
through the bag walls, the wall face acquires a cover of vegetation.
Soil of a quality sufficient to facilitate the growth of an adequate
vegetation cover, mixed with seeds, is a relatively expensive fill material
2S for use in sandbags. It would be desirable to reduce the cost while still
being able to grow a vegetation cover on sandbag walls.
Summary of the Invention
The invention is based on the principle that it is possible to grow
vegetation on a sandbag wall by using sandbags that are not completely
filled with soil, but have soil as a fill material at one end of the bag,
while
the rest of the bag is filled with other, cheaper, fill materials.
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The invention provides a sandbag for use in the construction of
sandbag walls. The bag has a bag wall, a first end and a second end and
the sandbag is filled with two or more types of fill material, a first type of
fill material, preferably soil mixed with plant seeds, being at the first end
of the bag and a second type of fill material being spaced from the first
end.
The invention also provides sandbag walls comprising multiple
courses of such sandbags. The sandbags are arranged such that the ends
that contain the soil form at least part of the outer face of the wall.
In this specification "fill material" means any material that is
suitable for use in bags in the construction of walls, including sand, soil,
gravel, dry mix concrete (which hardens after wetting and curing) and
mixtures thereof, including fill material with seeds for vegetation. The
term "sandbag" as used herein means a bag containing any "fill material".
For further clarity, the term is not limited to a bag in which the fill
material
is sand. The term "soil" includes any solid materials that are suitable for
use in sandbags to support the growth of plants from seeds mixed
therewith. The term "wall" as used herein in relation to structures made of
sandbags includes any array of sandbags that is suitable for the purpose of
erosion control (for example along shorelines, riverbanks, etc.), flood
control, retaining or stabilizing slopes or embankments, noise barriers,
landscaping, and for similar applications.
Brief Description of Drawing-s
Figure 1 is a perspective view of a sandbag according to an
embodiment of the invention.
Figure 2 is a perspective view of one course of sandbags of a
sandbag wall.
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Figure 3 is a cross-sectional view of a sandbag wall.
Figure 4 is a top plan view of a course of sandbags of a sandbag
wall according to another embodiment of the invention.
Detailed Description of the Preferred Embodiments
In the following description and drawings, corresponding and like
parts are referred to by the same reference characters.
l0 With reference to Figure 1 of the drawings, sandbag 10 comprises a
bag 12 filled with fill material 24. The bag has a wall 14, a closed bottom
end 16 and a top end 18, which has opening 20 that is closed by means of
a tie 22. The sandbag is accordingly sealed to retain the fill material
within its interior. The bag 12 is preferably made of geotextile and is
formed of a single piece thereof by sewing along the bottom and a
longitudinal side of the bag.
Sandbag 10 has a length L between its opposed ends 16, 18, and a
width W, and a depth, the length being greater than the width.
Fill material 24 comprises soil 24A mixed with plant seeds, which is
put at the bottom end of the bag, and a second fill material 24B, which
may be sand, gravel, etc., depending on the particular application and the
availability of such fill materials. If desired, mixtures of relatively
inexpensive fill materials may be used for fill 24B.
The soil 24A may fill any selected proportion of the bag volume.
For example, the soil may fill one-quarter, one-third, one-half, etc. of the
bag volume. Generally, it is desirable that the amount of soil be sufficient
to support the proper growth of vegetation, but for reasons of economy not
more than that. In some cases, the selection will depend on the particular
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application and the fill materials used. For example, a sandbag with about
one-third of the bag volume filled with soil and about two-thirds with dry
mix concrete would be suitable for an erosion control application where
land and water meet, as along a shoreline or the embankment of a river or
stream.
Referring Figs. 2 and 3, sandbags 10 are assembled into a wall 50
comprising a plurality of generally horizontal courses. Configurations of
sandbags forming retaining walls and other erosion control structures are
well known in the prior art, for example WO 00/61880, and bags 10 can be
employed in such configurations. Retaining wall 50 comprises multiple
generally horizontal courses 30 of sandbags, the courses being arranged in
a generally vertical or sloping configuration. In the present invention, the
bags in each course 30 are laid so that the bottom end 16 of the bags,
containing the soil/seed mix, is adjacent to the outer (i.e. exposed) face 32
of the wall and the opposite end 18 of the bags is adjacent the inner side 34
of the wall, i.e. adjacent to the backfill or slope 36 that is in back of the
wall. The sandbags 10 are accordingly positioned such that the soil/seed
fill material is at the outer face of the wall, to facilitate the growth of
vegetation on the wall face. This both enhances the appearance of the wall
and protects the bags from exposure to sunlight and weather.
Optionally, and preferably, interconnecting members 25 are used to
attach adjacent sandbags together, to strengthen the retaining wall. The
interconnecting members comprise a plate 27 having projections 29 on
both sides thereof which project into sandbags of vertically-adjacent
courses and into horizontally-adjacent sandbags. They may be of the types
described in WO 00/61880 (Kim).
The sandbags 10 of the invention may be used in wall structures in
conjunction with other sandbags which have only a single fill material.
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Fig. 4 shows one example of such an arrangement, out of the many
possible arrangements that can be made. Course 40 of the wall comprises
sandbags 10 alternating with sandbags 42 which have only a single fill
material. If it is desired to grow vegetation on the entire wall, the fill
material for sandbags 42 would preferably be soil mixed with seeds. The
sandbags 10 are positioned such that end 16 of the bags is adjacent to the
outer face 32 of the wall.
While exemplary embodiments have been discussed above, those of
skill in the art will recognize that certain modifications thereto may be
made. It is intended that the following appended claims are interpreted to
include all such modifications, as are within their true scope.
