Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DRAINAGE SYSTEM FOR TUNNELS
BACKGROUND AND SUMMARY OF THE INVENTION
The invention concerns a process for the manufacture of a drainage system
components for tunnels, and for tunnel drainage systems. The invention
comprises or
consists of multiple plastic parts for connection to each other, in the form
of shaped lengths
with an arched profile made of plastic having a ribbed surface contour and
angled lateral
sections on both sides, as well as moulded parts suitable for coupling and
attachment,
which are required in tunnel constructions in order to collect and drain
water. The
invention is particularly applicable to collection of water forced through the
rock surface of
1p the tunnel, and transports the water in a controlled manner under the
llnish covering,
especially shotcrete, to main collection conduits. The invention is also
concerned with a
drainage system for surface water emerging under pressure out of the tunnel
rock walls
under the finish covering, especially concrete, particularly in tunnel
constructions. The
invention preferably comprises or consists of arched shaped lengths with
angled lateral
parts on both sides, and a surface contour having ribs running perpendicular
to the
longitudinal axis and molded parts that ensure the connection of either
confluent shaped
lengths or the main collection conduit through overlapping, or the attachment
of collection
hoods, for instance to anchor heads.
EP-A1 -0 648 916 discloses shaped lengths of flexible sealing material, with
which
joints and gaps remaining in concrete cladding are covered over, in order to
collect the
water emerging therefrom in order to transport it away in a controlled manner.
The shaped
lengths comprise an arched middle part and lateral parts, capable of being
bent down,
molded onto the arched middle. The lateral parts are provided with contouring
in order to
improve adhesion to the concrete parts or other cladding elements of the
tunnel. What is
disadvantageous is that these known shaped lengths can only be used for
sealing or
additional sealing of gaps in finished concrete parts or similar cladding
elements and are
applied to these from the outside. Since they probably are of flexible sealing
material, and
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especially rubber, they would be so damaged by the covering shotcrete or
thereby
compressed that the water would no longer be able to flaw through them.
Furthermore,
attachment to the rock surface through adhesion is not, in practice, possible.
CH-PS 479 777 dated 1968 describes an open channel having laterally molded
edge strips to enable a better attachment to the rock surface. The channel
also posses a
stiffening wire which, being such, allows bending, that is flat compression,
of the channel.
The channel Is of a PVC film, and the stiffening wire is also provided with a
corresponding
PVC coating. These known open channels allow a certain degree of adaptation to
the
rock surface, although it has become apparent that the PVC material in use
does not allow
covering with shotcrete, Rather, here too, the channel is damaged to the
extent that
reliable removal of the water is no longer assured.
USP 3,699,684 reveals drainage pipes made of flexible material, whereby the
pipes
are placed into previously prepared incisions or channels, in order to
transport away the
water collected in them. Stiffening rings or wires are set into the material
at intervals, so
that they are best suited to horizontal drainage, since inlet openings are
provided at
intervals between the stiffening rings, through which the water can enter.
This full round
type of pipe is not suitable for drainage to be undertaken largely in a
vertical attitude.
Even if this pipe were simply to be halved, connection with or attachment to,
the rock
surface would not be possible. The openings provided at intervals between the
stiffening
rings would also prove to be disadvantageous in that case.
USPS 4,380,042 discloses a drainage pipe that is also intended for horizontal
drainage and which has a stiffening base part in which. there are openings in
order
immediately to conduct away the water leeching into the channel or drain. In
this case,
also, a ribbed surtace profile is provided, comprising wave troughs and crests
arranged in
equal separation from each other. There is a folded edge provided here,
although only in
order to facilitate connection to the base part, which provides the required
stiffening. The
entire body is of a -flexible material and is therefore, once again, not
suited for covering
with shotcrete when installed on the rock surface.
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The European patent application 96 810 239.2, in which the texts referred to
earlier
here are cited as the state of the art, describes a drainage system of a
suitably flexible
shaped length and associated molded pans, whereby bath the shaped lengths and
the
molded parts have a ribbed surface contour in the junction area and can
therefore easily
be joined to each other. The shaped lengths are equipped on both sides with
angled
lateral parts to enable connection with the rock surface, and angled folds at
the end into
which a sealant material is injected to prevent the egress of water. Here,
too, the shaped
lengths and the molded parts are made of a flexible material (i.e. plastic),
so that they can
be placed at the water exit points suitably bent, although they are damaged
and thereby
rendered unusable if the drainage system is covered with shotcrete, whereby
account
must be taken of the fact that, in order to make it adhere to the rock
surface, the shotcrete
has tv be applied under appropriate pressure. Even the ribbed surface
contouring is not
sufficient to prevent destruction of the molded parts or shaped lengths. Also
disadvantageous are the facts that no effective covering over of the water
exit locations in
the region of the anchor caps is possible, and that angling is difficult
despite wedge-
shaped notches provided for that purpose. Furthermore, as previously
mentioned, the
material is a flexible plastic, which does not permit manufacture of the
drainage system in
a sufficiently stable form.
The invention creates a drainage system in the form of a collection and
conduction
system that is simple to assemble and can be covered over with shotcrete while
ensuring
faultless transport of water. This is accomplished by utilizing films or thin-
walled boards
made from high density polyethylene (HDPE) of high impact resistance and tear
resistance
with a width chosen to be slightly greater than the subsequent shaped lengths.
The
boards are heated for deep drawing, and are drawn over a positive form by
application of a
vacuum, and are so molded that, over substantially the entire length in the
arched region,
the same surtace contouring with smooth lateral parts is produced. Deep
drawing of
plastic parts is conventional per se, as shown by U S Patent 4,818,465.
By utilizing a manufacturing process as described above, it is possible to
make an
arched shaped length that is designed, purely by virtue of its shape and the
material used
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to manufacture it, so that it can be covered over without difficulty using
shotcrete after its
installation on the rock surface. The very dense PE material with its high
level of impact
resistance protect against the more or less fine quartz particles contained in
the shotcrete,
without the possibility of any significant damage arising, so that, in any
event, the hollow
space through which (after covering with shotcrete) the surface water or the
water
emerging from the rock surface can be transported without causing any damage
to the
tunnel lining, remains intact. Of further advantage is the fact that., due to
the surface
contouring being substantially the same over the entire length, a secure
overlap, and
therefore linking with the molded parts, is possible. The molded parts also
possess
substantially the same surface contour in the joint region. An identical
profile of this kind
can be reliably manufactured using the deep drawing process so that, through
the
formation of the smooth lateral parts, that different from the form of the
arched area, a
sealing surface is created that is generally adequate to ensure that the water
flows through
the arched area and does not escape laterally. Solely in the case of special
ground or rock
surface areas might it be necessary to effect additional sealing by the use of
sealing
materials.
In a suitable embodiment of the invention, it is intended that molded parts
shaped to
fit the anchor heads or attaching points of the shaped lengths are deep drawn
from films or
thin-walled boards, so that they are given substantially the same or a
slightly larger than
contour, as the shaped lengths in the later joining regions. The molded parts,
which
secure only relatively short sections, are also preferably made from
substantially the same
material and in substantially the same manner, so that even with a
disadvantageously
applied covering of shotcrete, continuous drainage is assured. Profiling in
the joining
region makes possible a safe coupling to the relevant part of the shaped
length, and
without the need for any additional sealing material. Rather, by overlapping
of the shaped
parts provided with contouring and of the shaped lengths, a form of labyrinth
seat is
achieved that is adequate for this application. Through the process of
manufacture as
deep drawn parts, a consistent profiling and therefore a sure connection with
the shaped
lengths is assured.
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A particularly advantageous embodiment of the molded parts, kept to precise
specifications, is possible if films or boards of a thickness between about
4.8 and 1.5 mm
(and all narrower ranges within that broad range) and preferably about 1.2 mm,
are used
for the shaped lengths and the molded parts. With about 1 rnm and thicker
films (and
5 boards, too,) deep drawing is possible, as well as precise profiling when
deep drawing, so
that the connection of the individual parts of the drainage system is sure,
and so that there
is a sufficient wall thickness in all areas of the molded parts and shaped
lengths.
It has been shown that not every PE material is suitable for the manufacture
of
appropriately advantageous drainage systems according to the invention. The
invention
provides for the shaped lengths and molded parts to be manufactured out of a
HDPE with
a formulation corresponding to the plastic used for refuse bins. This material
has a very
high density and high impact resistance. sealing capability and other values,
which, as with
refuse bins, ensure adequate service life even under heavy loading.
With the help of the process according to the invention, a drainage system is
made
that comprises or consists of multiple parts, the drainage system itself is to
be protected,
and apart from the shaped lengths with angled lateral parts on both sides,
molded parts
are also provided that have ribs in the connecting region which are
substantially the same
as or correspond to those of the shaped lengths. The shaped lengths themselves
comprise or consist of an arched middle section with sine wave-shaped ribs and
the lateral
parts running at an angle thereto it without any contouring. The shaped
lengths may be
formed from a single piece from HDPE of a special formulation with a high
impact
resistance, and have single ribs at a predetermined distance from each other
and each
running through to the edges of the shaped length. A shaped length of this
type
possesses the necessary stability and impact resistance for the application of
shotcrete
thereto, and can be securely attached in the edge region to the rock surface
with nails,
anchors or similar structures, while simultaneously providing a seal because
the lateral
parts have a substantially flat, smooth surface. The lengths can be installed
bent
according to the prevailing conditions, since single ribs running through to
the edge are
provided at a substantially equal distance from each other, which permits
bending to either
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side. It is conceivable that the molded parts could also possess corresponding
single ribs,
although this is not necessary in general, if the single ribs had the relevant
dimensions,
because then a lack of seal in the upper region of the flat lateral parts
would not be
harmful.
A further embodiment of the invention comprises one in which the continuous
single
ribs are formed to be correspondingly substantially as broad as, or broader
than, the other
ribs. This means that overlapping (in order to connect neighboring drain
parts) is possible
without difficulty, because in the important area of connection with the rock
wall
substantially flat parts are present which do not pose a problem for
correspondingly proud-
standing single ribs. On the other hand, bending in practically all directions
is possible,
and therefore adaptation to the water emerging from various sites.
Particularly
advantageous in this respect is when the single ribs have the width of two
positive ribs and
one negative rib, since then the necessary bending is possible and, at the
same time, a
corresponding overlap is provided since one single rib overlaps two positive
ribs without
presenting any joint problems.
The formation of molded parts in the connection region so that an overlap or
connection with the neighboring shaped length is achieved is preferably made
possible by
providing the molded parts with coupling ribs corresponding to the ribs of the
shaped
lengths - that is, ribs that have slightly larger dimensions so that they can
be placed over
the ribs of the neighboring shaped length. However, the coupling ribs should
not be too
large, since then the necessary labyrinth seal could be impaired.
Of particular importance to the function of the invention is catching water
that
emerges in the region of anchor heads. Since the anchors or the holes drilled
to accept
them may possibly intersect several water-conducting slip planes and fissures,
wafer
leakage there is a particular problem. Therefore, the invention allows for the
molded
anchor parts associated with the anchor heads to have a cap that accepts the
anchor end,
anchor nut, and possibly the domed plate. In this way, a molded anchor part
can be
placed over the entire anchor head in order to seal this area and to ensure
that the water
emerging there is transported through the drainage system. This is
particularly so when
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the molded anchor part of the domed plate has a rectangular shape and a
receptive
sealing bead is formed around 'rt. The sealing bead simply ensures that the
emerging
water does not seek other routes, but is collected by the molded anchor part
and
transported away through the drainage system.
In this regard, it is desirable if the sealing bead is produced through
shaping, or
through tapering of the bent-over edges, an approximate linear contact with
the rock
surtace is produced. In this way, a seating bead in the proper sense, that is,
an additional
molded part, is not required at all. Rather, the entire molded part - the
molded anchor part
in this case - simultaneously provides the seating region, thus allowing a
simpler
manufacturing processes.
The rock surtace might comprise protruding parts in the area of the relatively
small
molded anchor parts. In order to achieve adaptation to the rock surface, the
invention
provides for the molded anchor parts to have molded ribs substantially the
same as, or
similar and running parallel to, the ribs of the shaped lengths. In this way,
the entire
molded anchor part can be easily bent and so adapted to the existing shape of
the rock
surface.
The prior art typically uses a main collection conduit, comprising a round
pipe,
probably also made of plastic. This round pipe can only be adapted to a
limited extent to
the course of the rock surface, which is not usually straight. This is helped
by the
embodiment of the invention in that the main collection conduit is made of
ribbed piping
such that its ribs are formed so that they correspond to the ribs of the
shaped lengths.
This means that the drainage system can be easily connected to the main
collection
conduit while, at the same time allowing a predetermined course of the main
collection
conduit along the rock surface.
An advantageous possibility for the connection of the drainage system to the
main
collection conduit is also provided for if this is made as a polygonal or
preferably
rectangular-section pipe, although a main collection conduit of this form
naturally does not
fit as well to the contours of the rock surface as the previously described
ribbed pipe.
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However, such a rectangular-section pipe can have advantages for particular
application
purposes.
The invention distinguishes itself in particular by providing a drainage
system that
can be used to particular advantage where shotcrete has to be applied for
stabilization of
the rock surface. Even under this problematic coating, maintenance of the
effectiveness of
the drainage system employed is assured since it is manufactured from the
particular PE
material described, so that when the shotcrete is applied, no particular
precautions need to
be taken. This applies both to the shaped lengths and to the molded parts.
Installation of
the shaped lengths is significantly simplified by the fact that the lateral
parts are simply
nailed onto the rock wall in order, at the same time, to produce the necessary
seal,
because the lateral parts have flat surfaces and so water cannot emerge
therefrom. The
molded parts can, through appropriate formation, easily be attached to the
ground or rock
wall as well as to the relevant shaped lengths, since, at least in the
coupling area they
possess corresponding ribs. Particularly advantageous are both the connection
of the
shaped lengths with the individual molded parts (particularly the molded
anchor parts) as
well as with the main collection conduit, so that it can be guaranteed with
the necessary
degree of certainty that pressurized water will not endanger the tunnel wall,
even after a
long service life.
According to one aspect of the present invention there is provided a method of
manufacturing a component of a drainage system comprising: a plurality of
plastic parts
connected together in the form of shaped lengths, with an arched profile
having a ribbed
surface contour and an angled lateral section on each side of the arched
profile; and a
plurality of molded parts for coupling the shaped lengths to each other and to
main
collection conduits; said method comprising: (a) selecting films or thin-
walled boards made
from high impact and tear resistance high density polyethylene and having a
width slightly
greater than the desired width of shaped lengths to be formed therefrom; (b)
heating the
films or boards from (a) to a conventional temperature suitable for deep
drawing; and (c)
by the application of a conventional level of vacuum, deep drawing the heated
films or
boards from (b) over a positive form to produce a shaped length having over
substantially
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the entire length thereof an arched profile with two sides, with a ribbed
surface contour,
and an angled lateral section on each side of the arched profile. The method
may further
comprise using the shaped length from (c) with other shaped lengths and molded
coupling
parts to provide a tunnel water drainage system.
The method may also further comprise: (d) selecting films or thin-walled
boards
made from high impact and tear resistance high density polyethylene and having
dimensions corresponding to molded coupling parts to be formed therefrom; (e)
heating
the films or boards from (d) to a temperature suitable for deep drawing; and
(f) by the
application of vacuum, deep drawing the heated films or boards from (e) over a
positive
form to produce a molded coupling part having a configuration with
substantially the same,
or slightly larger, contour as the portions of a shaped length to which the
molded coupling
part is to be connected; and connecting the shaped length from (c) and the
molded
coupling part from {f), together to provide a tunnel water drainage system. In
the method
(a) and (d) may be practiced by selecting a film or board having a thickness
between about
0.8 - 1.5 rnrn. {e. g. by selecting a film or hoard from a high density
polyethylene used to
make refuse bins and having a thickness of about 1.2 mm.)
According to another aspect of the invention there is provided a drainage
system for
tunnels having rock walls, comprising: a plurality of shaped lengths, each
with: an arched
profile having first and second sides, a plurality of ribs defining a ribbed
surface contour,
and a substantially flat angled lateral section on each of the first and
sides; the shaped
lengths capable of transporting water in a substantially leak-free manner in a
tunnel
environment; at least one main collection conduit for transporting water from
the shaped
lengths in or from a tunnel; and a plurality of molded parts coupling the
shaped lengths to
each other and to the at least one main collection conduit; and wherein the
shaped lengths
each comprise a substantially single piece of high impact and tear resistance
high density
polyethylene and having a plurality of spaced single ribs extending across the
arched
profile and substantially flat angled lateral sections. Preferably, the
plurality of molded
parts are also made of high impact and tear resistance high density
polyethylene, such as
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of the type used to make refuse bins. Preferably the high impact and tear
resistance high
density polyethylene has a thickness of between about 0.8 - 1.5 mm.
Preferably the single ribs are substantially as wide as, or wider than, the
ribs of the
ribbed surface contour. Also preferably the ribbed surface contour comprises
alternating
positive and negative ribs; and wherein the single ribs have a width
substantially equal to
two of the positive ribs and one of the negative ribs. Also, the coupling
parts typically
comprise coupling ribs in connecting regions thereof which correspond to the
ribs of the
ribbed surface contour of the shaped lengths. The drainage system also further
comprises
anchor heads, including an anchor bolt end, anchor nut, and domed plate,
provided in the
tunnel rock; and wherein the coupling parts include caps that accept the
anchor heads,
and are connected to the shaped lengths. Typically the caps have a
substantially square
configuration corresponding to that of the domed plate, and a sealing bead
formed
therearound far engaging the rock, and the caps have molded ribs substantially
the same
as the ribs of the ribbed surface contour of the shaped lengths. The sealing
bead may be
provided by shaping or tapering of a downward angled edge of a the cap.
In the preferred embodiment the at least one main collection conduit comprises
an
enclosed ribbed pipe having a plurality of ribs substantially corresponding to
the ribs of the
ribbed surtace contour of the shaped lengths. Also, the at least one main
collection
conduit preferably has a substantially polygonal (e. g. rectangular) cross-
section.
It is the primary object of the present invention to provide a simple yet
effective
method of making component parts for a tunnel drainage system, and an improved
tunnel
drainage system. This and other objects of the invention will become clear
from an
inspection of the detailed description of the invention, and from the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic simplified representation of a drainage system
according
to the invention attached to a rock wall;
FIGURE 2 is a top plan view of a shaped length of the system of the invention;
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FIGURE 3 is a partial cross-section in the area of the middle section, of a
shaped
length according to one embodiment of the invention;
FIGURE 4 is a plan view of an exemplary molded anchor part according to the
invention;
FIGURE 5 is a longitudinal cross-section of a molded anchor part according to
the
invention;
FIGURE 6 is a schematic cross-section of a drainage system installed on a rock
surface, or a shaped length in the drainage system, according to the
invention.
DETAILED DESCRIPTION OF THE DRAWINGS
FIGURE 1 shows a drainage system 1 mounted on a rock wall 2, so that the water
emerging from individual sections of the rock wall 2 can be reliably
transported to the main
collection conduit 4 laid on the tunnel floor 3. The drainage system 1
comprises or
consists of shaped lengths 5 with surface contouring 8 and smooth lateral
parts 6, 7. It
can be seen that the lateral parts 6, 7 are attached with nails 16, 17, or
like fasteners, to
the rock wall 2. It is not necessary to specify relevant points on the lateral
parts 6, 7,
although this may simplify installation, especially under difficult
conditions.
The surface contouring 8 comprises or consists of wave-shaped ribs 9, 10, and
11.
The ribs 9, 10, 11 comprise substantially regularly shaped waves, which
simpl'rfy
installation, and simultaneously improve the stability and simplify
application of shotcrete,
because they represent a form of adhesion zone for the shotcrete. This
multiple effect is
particularly advantageous in that in the area of the relatively narrow lateral
parts 6, 7 no
adhesion is provided, or at best only through the nails 1fi, 17,
The shaped lengths 5, 5', 5" are connected by the molded parts 1 Z, 13, 14 to
each
other or to appropriate other parts. Thus the molded part 12 serves to connect
shaped
length 5 to the main collection conduit 4 (aid on the tunnel floor 3, while
the substantially Y-
shaped piece -- that is the molded part 13 -- produces a branch so that the
shaped lengths
5' and 5" can run to the relevant anchor heads 15 at an angle to the central
shaped length
5. The anchor heads 15 are considered in more detail later on, and it will
only be
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mentioned here that the relevant anchor head 15 is fully covered by the molded
anchor
part 14.
FIGURE 2 is a plan view of part of a shaped length 5 which shows that only the
middle section 18 is provided with ribs 9, 10, 11. These ribs 9, 10, 11 are
distributed
evenly over substantially the entire length, and only at intervals are single
ribs 21 provided
that run right across to the edges 19, 20 of the shaped length 5. These single
ribs 21
enable or simplify curved installation of the shaped length 5 on the rock wall
2, as is
suggested FIGURE 1.
V1lhile the middle section 18 has ribs 9, 10, 11 and single ribs 21, in the
area of the
lateral parts 6, 7, there are no ribs, or only the continuous single ribs 2 1.
This flat shape
ensures that installation of the shaped lengths 5 is possible without any
additional
measures, i.e, special sealing measures. The narrow single ribs 21 do not
represent a
hindrance, so that it can otherwise be ensured with suitable measures that
these contour
ribs do not interrupt the seal zone.
FIGURE 3 shows how the single ribs 21 can be formed differently than in FIGURE
2. Here an arch-shaped single rib 21 is illustrated which has the width of two
positive ribs
22 and one negative rib 23. The single rib 21 can also be formed with a
relatively flat
shape, so that in both cases when the shaped length 5 is laid on the
connecting region 25
of molded parts 12, 13, 14, overlapping action is not hindered. When the
connecting
region 25 is laid on the shaped lengths 5, there may be a slight hindrance
under certain
circumstances which, however, can be compensated for by providing a
sufficiently broad
connecting region 25.
FIGURES 4 and 5 show a molded anchor part 14 in plan view and in cross-
section,
respectively, wherein it is clear that coupling ribs 26 are provided in the
connecting region
25, facilitating connection with adjoining shaped lengths 5 because the parts
are made
slightly broader.
In this design of the molded anchor part 14, it is important that it covers
the entire
anchor as far as possible, as is made clear in FIGURE 5. The anchor bolt 27
fastened into
the earth lies with the anchor end 28 and the anchor nut 29 protruding above
the rock wall
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2, so that the cap 31 covers not only this region, but also the entire domed
plate 30, which
allows for effective tightening of the anchor or the anchor bolt 27 using the
anchor nut 29.
FIGURE 5 shows that, in the region of the edge 34, either a sealing bead 32
can be
included or that a seal can be achieved through tapering of the edging 34. so
that water
cannot escape, but rather is caught in the molded anchor part 14 and is then
transported
through the connecting region 25.
FIGURE 4 shows a special embodiment with molded ribs 33. 33 formed so that the
molded anchor part can be bent according to the shape of the rock wall 2, to
provide a
better seal.
FIGURE 6 shows a drain 1 installed on a rock wall 2, wherein it is clear that
the
d rains of the invention cover, by way of example, water-conducting fissures
36 in order to
collect the water emerging from them and to transport it safely under the
shotcrete [not
shown]. Identifiable here are the fixing nails 37 that are inserted through
lateral parts 6, 7
into the rock 2 and thus enable effective attachment. In FIGURE 1 these fixing
nails are
identified as 16 and 17; these attachment means (e.g. nails 16, 17) can
alternatively be
small anchors or the like.
FIGURE 6 makes it clear that the lateral pal-is 6, 7 can possess a raised edge
38, in
order to introduce sealing material 39, or a turned down edge 40, which is
generally
adequate to concentrate the entire water flow in the region of the hollow
space 41. This
may possibly also be influenced in that the fixing nails 37 are not only
inserted, as shown
here, centrally in the lateral parts 6, 7, but offset close to the middle
section 18 or to the
edges 38, 40.
While the invention has been described in connection with what is presently
considered to be the most practical and preferred embodiment, it is to be
understood that
the invention is not to be limited to the disclosed embodiment, but on the
contrary, is
intended to cover various modifications and equivalent arrangements included
within the
spirit and scope of the appended claims.
