ECRAN ANTIBRUIT A STRUCTURE VEGETALE

A VEGETATIVE NOISE PROTECTION DEVICE

Abrégé français

La présente invention a pour objet un écran antibruit à structure végétale comportant deux parois latérales (1 et 2) retenant un substrat (3). Les parois latérales (1 et 2) sont constituées de branches de saule (5) rassemblées en rangs serrés de haut en bas et formant deux parois (4) retenues par compression à l'aide de tiges de serrage (6 et 7) réparties dans l'axe longitudinal du mur. En appui sur la surface extérieure de chacune des parois (1 et 2), au moins deux poteaux (9) enfoncés dans le sol (10) assurent le support de la structure. Les poteaux de soutien (9) disposés de part et d'autre des parois latérales (1 et 2) sont inclinés l'un vers l'autre et reliés par des tiges filetées (12). Une matière textile (8) permettant le passage des racines est interposée entre les branches de saule (5) et le massif structural (3).

Abrégé anglais

A vegetative noise protection device comprises two side
walls (1, 2), the space between the side walls (1, 2) being
filled with a substrate (3). The side walls (1, 2) are
erected from wall elements (4) formed by closely adjacent
willow branches (5) extending from the top to the bottom and
clamped between clamping rods (6, 7) extending in the
longitudinal direction of the wall. On the outside of each wall
element (4) there are at least two supporting poles (9)
protruding into the subsoil (10). The supporting poles (9) on
the two side walls (1, 2) are inclined toward each other and
interconnected by threaded rods (12). Between the willow
branches (5) and the space filled with substrate (3) there is
a root-permeable textile material (8).

Revendications

7
CLAIMS:
1. A vegetative noise protection device comprising two
side walls, the space between the two side walls being filled
with a substrate and the side walls being erected from wall
elements formed by closely adjacent willow branches extending
from the top to the bottom and clamped between clamping rods
extending in the longitudinal direction of the wall, at least
two supporting poles protruding into the subsoil being disposed
on the outside of each wall element, characterized in that the
supporting poles (9) are inclined toward each other and
interconnected by threaded rods (12), a root-permeable thin
layer (8) being disposed between the willow branches (5) and
the space filled with substrate (3).
2. The noise protection device of claim 1, characterized
in that the root-permeable thin layer (8) consists of a textile
material.
3. The noise protection device of claim 1 or 2,
characterized in that the willow branches (5) stand with their
lower ends on the soil (10, 16), a substrate bank (15) being
provided at the lower end of the willow branches (5) to press
against the willow branches (5) from outside.
4. The noise protection device of any of the above
claims, characterized in that the substrate is a mixture of
humus and foamed clay.
5. The noise protection device of any of the above
claims, characterized in that it is traversed in the
longitudinal direction by at least one irrigation pipe (17).
6. A method for making a vegetative noise protection
device by making wall elements (4) for erecting two side walls
(1, 2) to form a space (3) inbetween, which wall elements are

8
formed by closely adjacent willow branches extending from the
top to the bottom of the wall elements (4) and being clamped
between clamping rods (6, 7) extending in the longitudinal
direction of the wall elements (4), providing the wall elements
(4) on their inner side adjacent to said space (3) with a root-
permeable layer (8), driving at least two supporting poles (9)
into the subsoil (10) on the outside of each wall element (4)
so that the supporting poles on one side wall are inclined
toward the supporting poles on the other side wall,
interconnecting with threaded rods (12) the supporting poles on
one side wall with the supporting poles of the other side wall,
filling said space (3) with substrate up to below the clamping
rods (6, 7), removing at least the inner clamping rods (7), and
filling the space (3) further with substrate.

Description

, ~ ' CA 022136S~ 1997-08-19
A vegetative noise protection device
This invention relates to a vegetative noise protection
device comprising two side walls, the space between the side
walls being filled with a substrate and the side walls being
erected from wall elements formed by closely adjacent willow
branches extending from the top to the bottom and clamped be-
tween clamping rods extending in the longitudinal direction
of the wall, at least two supporting poles protruding into
the subsoil being disposed on the outside of each wall ele-
ment.
Such a noise protection device is known (DE 41 26 6~7
Cl~. It has proven useful in many places but serious problems
have also arisen.
In order to have the necessary stability and sufficient
thermal storage capacity at a sufficient height of e.g.
2.5 m, the known device is formed by a wide lower level which
has high stability and whose substrate has high water storage
capacity, and a narrower upper level whose poles protrude
into the substrate in the lower level from above. In order to
take up part of the pressure of the substrate on the lower
level side walls, the lower ends of the willow branches are
also inserted into deep ditches which must be produced with
considerable labor.
However, the main pro~lem of the known noise protection
device is that the poles driven into the lower level for the
upper level cannot withstand the pressure in the course of
time so that the upper level can tilt to the side or be de-
formed in another way. One has attempted to reduce the pres-
sure on the side walls and the poles in the upper level by
making the upper level thinner, but this causes the upper
level substrate to dry out too fast.
The problem of the invention is to provide a stable,
high, thoroughly moistened and effective noise protection de-

CA 022136~ 1997-08-19
vice of the abovementioned kind with relatively small thick-
ness.
This is obtained according to the invention by the sup-
porting poles on both side walls being inclined toward each
other and interconnected by threaded rods, a root-permeable
thin layer being disposed between the willow branches and the
space filled with substrate.
Due to the inwardly inclined supporting poles on both
side walls, the space with substrate tapers upward so that
the pressure on the side walls decreases from the bottom to
the top. This clearly reduces the force tending to press the
supporting poles outward.
The supporting poles are driven into the ~rown soil,
which can be additionally compacted. The length of the poles
corresponds approximately to the height of the noise protec-
tion device plus the length of the portion driven into the
soil. The willow branches can protrude upward beyond the sup-
porting poles. Altogether the height of the noise protection
device above the ground can be e.g. 2.50 m at a width of e.g.
1.20 m at the bottom and 0.80 m at the top. The angle of in-
clination of the supporting poles and thus the side walls is
preferably 80 to 88~.
The supporting poles on one side are further connected
with the diametrically opposite supporting poles on the other
side of the device by threaded rods in order to brace the
poles mutually.
Deformation of the inventive device is in addition pre-
vented by the root-permeable layer disposed on the inner side
of the side walls. At places with thin willow branches out-
ward deformations can occur on the device, in particular when
willow branches dry out and die. However, the thin layer
evens out the pressure of the substrate on the willow
branches of a side wall, thereby counteracting such deforma-
tion. The root-permeable layer can be for example a textile
material with meshes through which the roots of the willows

CA 022136~ 1997-08-19
can pass into the substrate and which widen as the roots be-
come thicker.
In the inventive device the willow branches stand with
their lower ends on the grown soil or on humus or a similar
substrate. This ensures a sufficient water supply for all
branches. The willows therefore take root after a very short
time and quickly produce, through the abovementioned root-
permeable layer, a thorough rooting and thus consolidation of
the substrate between the side walls.
In order to improve the water supply to the willow
branches one provides in the lower area of the device a humus
or similar substrate bank which presses against the willow
branches from outside. The bank thus produces further dimen-
sional stabilization of the inventive noise protection de-
~ vice.
The substrate between the side walls preferably consistsof a mixture of humus and foamed clay. The proportion of
foamed clay in the mixture can be 40 vol% and more. However,
it is normally 10 to 30 vol%. Since foamed clay has a very
low specific weight, this measure achieves a further substan-
tial pressure relief. The concentration of foamed clay can
vary within the device, being in particular higher in the up-
per area than in the lower area of the noise protection de-
vice.
The foamed clay at the same time stores water, thereby
counteracting the drying of the substrate.
Since the inventive noise protection device already en-
sures sufficient noise protection with a relatively small
thickness, thus requiring a relatively small substrate vol-
ume, there is a danger of the substrate drying out. In order
to prevent this one preferably lays irrigation pipes in the
substrate in the longitudinal direction of the device. For
the density of the moistened substrate and thus the pressure
on the side walls to decrease from the bottom to the top, the
irrigation pipes are preferably disposed in the lower half of
the device.

CA 022136~ 1997-08-19
The inventive noise protection device is preferably
erected as follows. The supporting poles are first beaten in
with the desired inclination on one side. The wall elements
are fastened temporarily to the supporting poles, being
screwed on for example. The wall elements for the other side
wall are then leaned against the thus fastened wall elements,
whereupon the supporting poles are beaten in with the desired
inclination on the other side of the noise protection device.
The leaning wall elements are then fastened temporarily to
these poles.
Before the space between the side walls thus formed by
the wall elements is filled with substrate, the thin root-
permeable layer is provided on the inner side of each side
wall. The space between the side walls is first filled with
~ substrate up to below the clamping rods of the wall elements
or, if the wall elements have a plurality of pairs of clamp-
ing rods disposed one above the other, up to below the lower-
most pair of clamping rods.
The clamping rods serve primarily to hold the willow
branches together during storage and transport and during
erection of the inventive protection device. It has turned
out that if the clamping rods remain in the noise protection
device the willow branches can be attacked by fungus in the
area of the rods.
Thus, at least the inner clamping rods are preferably
removed when the space has been filled with substrate up to
below the rods. If a plurality of pairs of rods are disposed
one above the other on the wall elements, the lowermost inner
rods are first removed, then substrate is added further up to
below the pairs of rods thereabove, then the inner rods of
these pairs removed, etc.
When the lower area of the space between the two side
walls is filled with substrate, the wall elements are fixed
sufficiently to permit the mounting of the horizontally dis-
posed threaded rods extending perpendicular to the longitudi-
nal direction of the device for bracing the pairs of support-

CA 022136~ 1997-08-19
ing poles on opposite sides of the device. A plurality of
threaded rods can mutually brace the pairs of diametrically
opposite supporting poles.
In the following an embodiment of the inventive noise
protection device will be explained more closely by way of
example with reference to the drawing, in which:
Fig. 1 shows a cross section through the noise protec-
tion device;
Fig. 2 shows a side view of a portion of the noise pro-
tection device.
According to Fig. 1 the noise protection device com-
prises two side walls 1, 2, the space between side walls 1, 2
being filled with substrate 3, for example a mixture of humus
and foamed clay.
Side walls 1, 2 are erected from wall elements 4. As
shown in Fig. 2, each wall element 4 consists of willow
branches 5 extending vertically from the bottom to the top
and held together by a lower and an upper pair of semicircu-
lar clamping rods 6, 7 interconnected with screws, cords or
the like. Willow branches 5 can have for example a diameter
of 1 to 4 cm, pre~erably 2 to 3 cm.
On the inner side of side walls 1, 2 there is root-
permeable thin layer 8, for example a large-meshed textile
material.
Side walls 1, 2 or wall elements 4 are supported on sup-
porting poles 9 which are beaten into grown soil 10 so as to
be inclined inward.
Two supporting poles 9 are diametrically opposite each
other on both side walls 1, 2 in each case. They are braced
at the bottom and top with two threaded rods 12. Threaded
rods 12 protrude through bores 14 in poles 9, nuts 13, for
example wing nuts, being screwed on the threaded portions
protruding out of poles 9 and shims being provided between
nuts 13 and poles 9. Threaded rods 12 are for example zinced
or made corrosion-resistant in another way.

CA 022136S~ 1997-08-19
-- 6
In the lower area of willow branches 5 there is humus
bank 15 pressing against willow branches 5 from outside. Fur-
ther one can provide humus fill 16 below the device in a cor-
responding excavation in grown soil 12, for willow branches 5
to stand on with their lower ends.
As shown on the left in Fig. 1, inner clamping rod 7 can
for example be removed upon erection of the device. Also,
both clamping rods 6, 7 can optionally be removed when space
3 has been filled with substrate 3 up to below the particular
pair of clamping rods 6, 7.
In the lower area of the space or substrate 3 between
the two walls 1, 2 there are right and left irrigation pipes
17 extending in the longitudinal direction of the protection
device. Irrigation pipes 17 can be formed by perforated
tubes. To prevent the pores of the perforated tubes from
clogging one can use double-walled tubes, the inside tube for
supplying water being perforated while the outside tube
spaced therefrom is provided with a fiber layer, for example
coconut fiber, for keeping the roots from penetrating into
the space between the inside and outside tubes.

Dessin représentatif