Patent Description:
There are many civil works scenarios where wall structures are required. In some instances these wall structures are made as mounds of self supporting material. In other instances the wall structure boundary is defined by and supported by a multiplicity of substantially vertically disposed concrete panels. The concrete panels allow much steeper wall definition boundaries then mounds of self-supporting material can usually provide. Where concrete panels are used in these situations there arises the problem in some instances of requiring that the resulting wall should be substantially impermeable to the passage of water or like liquids or fine solids such as sand or soil therethrough. This requirement can apply to liquid flow in a direction from within the wall structure to external the wall structure or vice versa.

As one might expect in civil works there can be movement of the wall structure over time. More particularly there can be movement of adjacent panels with respect to each other. This presents a problem to providing reliable seal of the gaps between the panels.

<CIT>discloses use of a thermosetting polymer resin as a seal between adjacent panels. Its stated virtue is its hardness. Such an arrangement is not flexible and not at all suited to situations where there is movement between adjacent panels.

<CIT>likewise discloses a seal system for vertical joints between abutting concrete panels in which the seal members are partially embedded in the panels to emerge at niches at the corners of the panels. These corner niches form a confining channel when the panels are in situ making it difficult to heat weld a strip over the ends of the seal members, or even more difficult, welding the overlap of one of the members over the other. Other disadvantages of the Bachy arrangement arise in that firstly, the filling in of the channel after welding prevents access to the seal for inspection and secondly, allows for virtually no flexibility of movement between the panels.

It is an object of the present invention to address or at least ameliorate some of the above disadvantages.

The term "comprising" (and grammatical variations thereof) is used in this specification in the inclusive sense of "having" or "including", and not in the exclusive sense of "consisting only of".

The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.

Accordingly, the invention provides a flexible seal system according to claim <NUM>. In particular, the flexible seal system comprises:
a first flexible seal member locatable proximate a first end of one said concrete panel; said first flexible seal member including:.

wherein the overlap component of the first flexible seal member is structured and selected in use to overlap the surface component of the second flexible seal member sufficient to permit welding of at least a portion of said overlap component of said first flexible seal member to at least a portion of said surface component of said second flexible seal member so as to form a continuous welded seal between and along the length of said first flexible seal member and said second flexible seal member. Preferably, the length of the first flexible seal member and the second flexible seal member is a longitudinal length.

Preferably, the first flexible seal member is homogeneous.

Preferably, the second flexible seal member is homogeneous.

Preferably, the first flexible seal member is cast into a concrete panel by immersing its anchor component into at least a surface region of the concrete panel prior to the setting of the concrete from which it is formed.

Preferably, the anchor component comprises a projection extending from the flexible seal member.

Preferably, the projection includes a bulbous portion or enlarged angular portion at a free edge thereof.

Preferably, the flexible seal member extends substantially around the entire periphery of each concrete panel.

Preferably, the anchor component comprises a substantially continuous extension, extending substantially, continuously, longitudinally, for the length of the flexible seal member.

Preferably, the anchor component comprises a substantially discontinuous, periodic extension, extending substantially, longitudinally, for the length of the flexible seal member.

Preferably, individual panels are one or more of square, rectangular, or cruciform.

Preferably, each of the panels is provided with at least one conventional tie back suitable for anchoring the panels to back-filled, compacted soil areas.

In a particular preferred form, the panels are precast panels.

In an alternative preferred form, the panels are cast in situ.

Preferably, the length of the first flexible seal member and the second flexible seal member is a longitudinal length.

In preferred forms, the panels are shaped.

In a particular preferred form, the panel is arched.

Embodiments of the present invention will now be described with reference to the accompanying drawings wherein:.

The present invention is drawn to a flexible seal system for sealing the joints between abutting concrete (or other settable material) panels. In each of the below described embodiments, each panel is prepared when cast with flexible seal members of two distinct configurations; a first flexible seal member and a second flexible seal member. Both the flexible seal members include at least one anchor component embedded within the concrete and a surface portion which extends over, or overlays, a portion of the outer surface of the panel. The first flexible seal member is distinguished from the second flexible seal member in that an overlap portion extends from its surface portion in such a way that the overlap portion extends beyond the edge of the panel.

With reference to <FIG>, there is illustrated a first embodiment of a flexible seal system <NUM> used to create a substantially watertight seal between, in this instance, a first concrete panel <NUM> and a second concrete panel <NUM>. As shown in the plan view there is a first flexible seal member <NUM> proximate a first end of concrete panel <NUM>. First flexible seal member <NUM> includes a surface component <NUM> extending over, and anchored into, a surface region <NUM> first concrete panel <NUM>. In this instance the first flexible seal member <NUM> further includes at least an anchor component formed as legs or elongate flanges 15A,15B which, in this instance project substantially normal from and are cast into the surface region <NUM> of the first concrete panel <NUM>, leaving the surface component <NUM> exposed above surface region <NUM>. Each of the legs 15A, 15B ends in an enlarged portion for securely embedding the anchor components in the concrete of the panel. The first flexible seal member <NUM> further includes an overlap component <NUM> mechanically supported by and extending from the surface component <NUM> to extend past the end of the concrete panel <NUM>. The first flexible seal member <NUM> thus described is shown in profile <NUM> of <FIG>.

The flexible seal system <NUM> further comprises a second flexible seal member <NUM>, disposed proximate a second end of an abutting concrete panel <NUM>, comprising, in this instance, a surface component <NUM> extending over a portion of the surface region <NUM>. Second flexible seal member further includes an anchor component <NUM> in this instance in the form of a first leg <NUM> A and a second leg <NUM> B projecting preferably substantially at right angles from surface component <NUM>,. The legs <NUM> A and <NUM> B are cast into the surface region <NUM> of second concrete panel <NUM> in such a way as to anchor surface component <NUM> reliably into the second concrete panel <NUM> whilst leaving surface component <NUM> exposed above surface region <NUM>.

The flexible seal members are arranged so that each concrete panel is provided with a first flexible seal member along each of a first pair of contiguous edges and with a second flexible seal member along each of a second pair of contiguous edges. Thus the differences between the first and second flexible seal members provides, in this embodiment, for sealing around both the vertical and horizontal edges of the panel.

As shown in the plan view of a concrete panel <NUM> prepared with the flexible seal system of the invention in <FIG>, the ends of the first flexible seal members <NUM> at their intersection <NUM> are mitrered and welded to form a watertight continuous seal surface. Similarly the second flexible seal members <NUM> at their intersection <NUM> are mitrered and welded. The junctions <NUM> between first and second flexible seal members are also mitrered and welded so that there is formed a continuous seal surface at the perimeter of the concrete panel. The cross sectioned view and enlargements of <FIG> show the disposition of each of the first and second flexible seal members and their anchor portions relative the opposite edges of the concrete panel.

The concrete panels of this preferred embodiment may be formed as follows. The flexible seal members are prepared in lengths to suit the dimensions of the panel to which they are to be applied and the ends mitrered as described above. The first and second flexible seal members are then welded at their intersections to form the continuous seal surface and positioned over formwork for the pouring of the concrete, with the anchor members suspended relative the formwork so as to become embedded within the concrete, and leaving the surface components extending over the surface. One the concrete has set, pressure testing of the flexible seal members completes the process.

Each of the first and second flexible seal members comprises an integral polymer structure. In use the first concrete panel <NUM> and the second concrete panel <NUM> are juxtaposed in sufficiently close relationship that overlap component <NUM> or at least a portion of it overlaps a longitudinal length of at least a portion of the surface component <NUM> as shown in the plan view of <FIG> thereby to define a weld zone <NUM>.

It should be noted that the surface component extending along an outer surface of the concrete panel with the overlap portion disposed as shown in <FIG> and <FIG>, affords considerable flexibility to the seal of the invention, allowing some movement between two adjacent panels in at least two directions. Moreover, the relatively short distance the anchor components of the two flexible seal members intrude into the concrete allows the flexible seal system of the invention to be used with relatively thin concrete panels. This may be contrasted for example with the arrangement of <CIT>discussed above, in which the arrangement of the flexible seal members require a much greater thickness of panel. It is noted also that the Bachy system creates an inherent weakness in the concrete by the long intrusion likely to lead to cracking.

The overlap component <NUM> and surface component <NUM> are made from a weldable plastics material whereby, following the juxtaposition of the adjacent panels the overlap component <NUM> is welded along its length to the surface component <NUM> by means not shown. Preferably, the overlap component of the first flexible seal member is of thinner or more pliable than the anchor components.

Preferred materials for the flexible seal members <NUM>, <NUM> include plastics materials, in particular, plastic materials which have the capacity to stretch and flex and preferably to be welded one to the other.

Suitable materials include polymers; HDPE; PVC; Teflon and polymer blends. Preferably these materials may be particularly selected and optimized for properties such as elongation, resistance to chemicals, and resistance to heat. Polyethylene and polypropylene are particularly suited for petrochemical applications. PVC or PET may be suited to water applications.

Preferably the same material is used for both the first flexible seal member <NUM> and the second flexible seal member <NUM> thereby to assist in homogeneity of the weld (see below).

A preferred process of welding is thermal fusion welding utilising a modified plastics extruder machine (not shown) that can be hand operated and which extrudes a molten bead of High Elongation resin through a "stepped" die head over an overlapping weld zone <NUM>. Preferably the weld zone <NUM> is prepared via abrasion prior to extrusion welding to remove surface grit and contamination.

In preferred forms the weld consumable comprises the same material composition as that of the first flexible seal member <NUM> and second flexible seal member <NUM>. At <FIG> is a side section view of a preferred form of weld showing the consumable <NUM> enveloping a beveled edge portion of the overlap component <NUM> and at least a portion of the surface component <NUM>.

Preferably, each weld is tested for water tightness at the completion of the weld. In a preferred method, after preparing the seal to be tested with a suitable liquid, a plexiglass dome, provided with a seal around its periphery, is placed over the area to be tested and a partial vacuum created under the dome to show up any imperfections. This testing is facilitated by the ready access available to the overlap component of the first flexible seal member and the bead of welding along the overlap edge.

With reference to the wall panel plan view of <FIG> a preferred arrangement for the first concrete panel <NUM> is to have a flexible seal member of the first flexible seal member <NUM> aligned along a first edge <NUM> thereof and to have a second flexible seal member <NUM> aligned along an opposite parallel second edge <NUM> thereof as illustrated. Panels of like types and flexible seal member arrangements can then be juxtaposed side-by-side in the manner illustrated in the adjacent wall panels plan view of <FIG>. In this embodiment a preferred distance between edges of adjacent panels is approximately <NUM> and with the opposed anchor component inset approximately <NUM> from an edge of an opposed panel edge with the overlap component extending approximately <NUM> from an edge of the panel into which it is anchored so as to thereby provide a weld zone of around <NUM> and where the face of the surface region of the second flexible seal member over which it extends is of the order of <NUM> in width.

Typical precast concrete panel or cast in situ panel dimensions can be of the order of <NUM> x <NUM> or as required by the application. The panels themselves may be square, rectangular, cruciform, arched or other suitable shapes preferably adapted for adjacent abutting of long edges thereof.

In preferred forms the flexible seal members are applied on the "inside" of the resulting barrier structure. That is to say on the side abutting the material or liquid which is being retained by the structure.

With reference to <FIG> there is illustrated a second embodiment of a flexible seal system <NUM> wherein like components are numbered as for the first embodiment described with reference to <FIG> except in the <NUM> series. In this instance first flexible seal member <NUM> includes a single anchor component <NUM> subtending from a surface component <NUM> which, in this instance, then extends integrally to the overlap component <NUM>.

The overlaps of the arrangement of <FIG> are approximately the same as for the arrangement of <FIG>.

With reference to <FIG> there is illustrated a third embodiment of a flexible seal system <NUM> where like components are numbered as for the first embodiment described with reference to <FIG> except in the <NUM> series. The construction of the flexible seal members <NUM>, <NUM> is substantially the same as that for the first embodiment. In this instance the second flexible seal member is placed as close to an edge of the concrete panel as possible rather than inset <NUM> as was the case with the arrangement of <FIG>. Correspondingly the extension of the overlap component <NUM> may be reduced to <NUM> as a result.

As shown in <FIG> further panels can then be stacked on the initial longitudinal alignment of panels and joined by welds along all four edges to create a wall structure of substantially any length and any height. In this instance a wall structure <NUM> is comprised of lower juxtaposed panels <NUM>, <NUM> joined at weld zone <NUM> above which are placed further panels <NUM>, <NUM> which are themselves joined at weld zone <NUM>. Upper panel <NUM> is joined at weld zone <NUM> to lower panel <NUM> whilst upper panel <NUM> is joined to lower panel <NUM> at weld zone <NUM> thereby to form a wall structure comprised of four concrete panels.

<FIG> illustrates the cross section a staged wall construction that may be applied with a vantage in some circumstances.

The wall panel arrangement of <FIG> or <FIG> can be used by way on non-limiting example of a dam wall, tunnel arch, tank farm vertical bund wall, sea wall.

In addition, in respect of any one of the above described embodiments, a fire-resistant/heat-resistant/chemical-resistant/UV-resistant expandable and/or flexible sealant or mastic may be inserted in the gap region between adjacent panels. In some forms this will be for the purpose of providing UV resistance. In other forms it will be for the purpose of providing heat resistance. In some forms this will be particularly for protecting the welded flexible seal.

The above described system can be utilised as part of a methodology to reclaim landfill volume.

With reference to <FIG> there is illustrated a berm <NUM> traditionally used to define a boundary for a landfill volume.

An alternative arrangement which permits use of substantially the volume of the berm involves use of a substantially vertical wall structure <NUM> thereby permitting use of volume <NUM> that otherwise would be occupied by the berm itself.

Advantageously, the vertical wall structure <NUM> is constructed utilising the arrangements described with reference to the earlier embodiments of <FIG>.

With reference to <FIG>, a preferred system which can be used as part of a landfill system includes:.

In some applications a liner may be applied to the filling area <NUM>. In some applications a contiguous liner may be applied over the inside face of the wall structure <NUM>, <NUM>.

Applications for embodiments of the invention described above include, but not are limited to:.

In a preferred arrangement in which the concrete panels with the flexible seal system of the invention are used for the sequential erection of a wall defining the boundary of refuse land fill, the concrete panels are erected with the flexible seal members on the rear surface of the panels, that is away from refuse land fill. In this arrangement, the flexible seal member along the lower horizontal edge of the lowermost or first row of panels of the wall, is the second flexible seal member described above and designated <NUM> in <FIG> and <FIG>. A liquid proof seal between the wall and ground cover sheet of the land fill area can then be made by extending the polymer ground sheet of the land fill surface to lie under the foundation or toe of the wall to curve upward and, after the concrete panels are erected, welding the edge of the ground cover sheet to the flexible seal member of the panel.

With reference to <FIG>, there is illustrated a wall seal system <NUM>, in accordance with an alternative example not covered by the appended claims, wherein like components are numbered as for earlier embodiments, except in the <NUM> series.

In this instance, the overlap component <NUM> comprises a separate component from the first flexible seal member <NUM> and the second flexible seal member <NUM>. Accordingly, in use, the adjacent wall panels <NUM>, <NUM> are juxtaposed and then the overlap component <NUM> is applied so as to overlap at least a portion of both the first flexible seal member <NUM> and the second flexible seal member <NUM>, and substantially along the entire length thereof. The overlap component <NUM> is then welded to both flexible seal members <NUM>, <NUM>.

This alternative example is also suited for use in most situations where the previously-described embodiments are applicable.

In this preferred arrangement of the invention, wherein like components are numbered as for earlier embodiments, except in the <NUM> series, the panels described above are arranged to form an irrigation channel <NUM> as shown in the cross section view of <FIG>. Typically, many conventional irrigation channels <NUM> are formed in the manner shown in the cross section view of <FIG> (prior art). These channels are formed by excavating a relatively shallow broad ditch <NUM> with the excavated material arranged in berms <NUM> on either side of the formed channel. In most cases, the sides of the channel are no more than compacted earth which degrades the water carrying efficiency through seepage. In some cases, the bottom and sides of the channel may be lined with concrete to prevent loss through seepage. In both cases however, the surface area <NUM> exposed to evaporation is large relative to the volume of water per unit length of the channel.

With reference now to <FIG>, in the present preferred arrangement, panels <NUM> provided with first and second flexible seal members as described above and as shown in the various embodiments of <FIG>, are arranged in an excavated channel <NUM> in rows to form substantially vertical, twin opposing walls <NUM> and <NUM>. In this instance, each of the panels <NUM> may be provided with at least one conventional "tie back" <NUM> anchoring the panels to the back-filled, compacted soil areas <NUM> and <NUM>. In at least one preferred form, the proximate ends of the tie back elements <NUM> may be cast into the rear portions of the panels <NUM>. In a more preferable arrangement, the panels <NUM> may be provided on their rear sides with securing elements (not shown) cast into the concrete for attaching the tie back elements thereto.

Depending on the desired depth of the channel to be constructed, and on the size of the panels to be employed, a number of panels <NUM> are arranged stacked one on top of another to a level at which the twin opposing vertical walls <NUM> and <NUM> extend above the level of the adjacent ground surface <NUM>. The panels may be stacked in vertical alignment or may be staggered by a proportion of their length. Preferably the walls extend a metre above the surface, or to a level where access to the channel by wild and feral animals is prevented.

As described above, the flexible seal members anchored in each of the panels, are arranged so that a first flexible seal member of the type labelled <NUM> (<NUM> in <FIG> or <NUM> in <FIG>) is at the lower edge of the panel while the second flexible seal member of the type labelled respectively <NUM> (<NUM> in <FIG> and <FIG>), is disposed at the upper edge. Thus as shown in the enlarged view of a section of the wall <NUM>, the overlap component of the first flexible seal member <NUM> overlaps the surface component of the second flexible seal member <NUM> along the surface of the wall. When welded in the manner described above, the flexible seal members provide a waterproof seal over the horizontal joints between the stacked panels.

Panels <NUM> are further provided with complementary flexible seal members at their vertical edges and the panels positioned such that a flexible seal member <NUM> is adjacent to a flexible seal member <NUM>. Thus similarly, the vertical joints between longitudinally abutting panels may also be sealed by the welding of the overlapping portion of flexible seal members <NUM> to flexible seal members <NUM>.

The overlap portions of the first flexible seal members <NUM> of the lowermost panels <NUM> and <NUM> of each of the walls, may be bent and laid against the surface of the bottom <NUM> of the channel as shown in <FIG>. A liner <NUM> of a compatible impervious polymer material is then laid to overlap the flexible seal members and preferably welded to them in the same manner as already described to provide a watertight flexible seal between the twin opposing walls of the channel.

It can be seen that the method of construction of irrigation channels by means of the panels of the invention provides a number of advantages over conventionally constructed channels. Firstly the panels are easily and rapidly erectable, especially, if in a preferred form, cast in low density concrete. Secondly the cast-in flexible seal members provide a simple and effective means of making the joints between abutting panels watertight. Furthermore the overlap components of the flexible seal members at the lower edges of the lowermost panel provide a unique element for the welded attachment of a liner for the bottom of the channel. Finally, the relatively narrow surface area to depth of the channel minimises water loss through evaporation.

With reference now to <FIG>, in this further preferred arrangement of an irrigation channel <NUM>, wherein like components are numbered as for earlier embodiments and arrangement, except in the <NUM> series, precast concrete panels <NUM> provided with first and second flexible seal members as previously described, again form the opposing walls of the channel. In this instance however, the walls comprise of series of single vertical panels <NUM> extending the depth of the channel.

Panels <NUM> are located in spacer elements <NUM> laid along the bottom of a prepared trench at intervals equal to the width of the panels <NUM>. The lower edges <NUM> of the panels <NUM> are retained in grooves <NUM> formed in the ends of the spacer elements <NUM>. Similar spacer elements <NUM> are located along the upper edges <NUM> of the panels <NUM> to form a controlled structure, with generally parallel vertical walls.

Sealing along the vertical joints <NUM> between adjacent panels <NUM> is by means of the first and second configured flexible seal members described above, with the overlap component <NUM> of the first configured flexible seal member of one panel, welded to the surface portion of the second configured flexible seal member <NUM> of the adjacent panel. Usually, though not necessarily, the panels <NUM> will be erected with the first and second flexible seal members directed to the inside of the irrigation channel as shown in <FIG>, but in some applications the flexible seal members may be disposed on the outside of the panels.

Panels <NUM> of this preferred arrangement are provided proximate their lower edges with a flexible seal member <NUM> of the form described above as the second configured flexible seal member. That is, a flexible seal member extending across the width of the panel <NUM> and comprising a surface component from which project at least two anchor components embedded into the concrete of the panel.

The bottom of the channel <NUM> may be formed of a sheet <NUM> of polymer material compatible with that of the flexible seal members of the panels. These sheets forming the base of channel are formed or folded into a channel form with upturned flanges <NUM> which are then welded to the flexible seal members (not visible) along the lower edges of the panels. The sheets are of a length to overlap the width of the panels (as well as the spacer elements) so that the edge of an overlap of one sheet may be welded to the surface of the next adjacent sheet. Alternatively, the sheet <NUM> may be of sufficient length to extend past a number of panels <NUM> and spacer elements <NUM>.

By these means, the vertical joints between panels <NUM> and the bottom of the channel <NUM> are rendered water tight by the welding of the various flexible seal members and bottom sheets.

In some applications it may be desired to clad the bottom of the channel with concrete slabs extending between adjacent spacers so at to provide a protective floor over the polymer sheets. By this means for example, mechanical equipment may be used to clean the channel from sediment and accumulated debris.

The construction method illustrated in <FIG> allows for a minimum of excavation and obviates the need for "tie back" of the panels into the adjacent soil body. Although for irrigation channels, the top of the channel <NUM> will usually remain open, it will be understood that the upper spacer elements <NUM> (or the upper edges <NUM> of the panels <NUM>) may provide support for concrete cover slabs or other coverings, such as a security mesh for example.

In at least one preferred arrangement, the panels <NUM> are provided proximate their upper edges <NUM> with first flexible seal members as described above. The channel may then be covered over with panels provided on their undersides with flexible seal members according to the invention to which the overlap components of the flexible seal members of the vertical panels may be welded. Thus the channel in this arrangement may become a fully sealed conduit or tunnel for the movement of liquids under some pressure.

Although the above arrangements are drawn to an irrigation channel, it will be appreciated that the panels and the wall seal system of the invention may be applied to other liquid conveying channels such as storm water channels for example. It will further be appreciated that although the above described panels are planar, the flexible seal members of the invention may equally be applied to the edges of curved panels to form arched structures.

In one arrangement the panels and the seal system of the invention may be adapted for the construction of a tunnel for the conveyance of cabling or traffic for example. In this case the vertical and horizontal panels are arranged with the flexible seal members on the outward surfaces of the panels to make the joints between panels proof against external hydraulic pressure.

In yet a further arrangement of the invention, the seal system may be applied to the seal of tunnels formed of curved panels to form arches as shown in <FIG>. Considering firstly the tunnel arrangement shown in <FIG>, it can be seen that the tunnel <NUM> comprises a series of one-piece arched units <NUM> supported in a base slab <NUM>, with the ends of the arched units <NUM> located in channels <NUM> cast into the base slab <NUM>. Watertight flexible seal at the base of the arched units <NUM> of this arrangement of the tunnel <NUM> may include bedding the ends of the arched units <NUM> in a seal compound within the channels <NUM>. Alternatively, sealing along the channels may be achieved by providing the outer ledge <NUM> of the channels with a flexible seal member of the second type as described above; that is a flexible seal member comprising a surface component <NUM> extending between two anchor components <NUM> as can be seen in the enlargement of <FIG>. The surface components <NUM> provide for sealing with overlap components of first flexible seal members provided on the arched unit as explained below.

The curved panels <NUM> for the tunnel <NUM> of <FIG>, are analogous to the panels for vertical walls described above and as illustrated in <FIG>. in which a curved panel <NUM> and its flexible seal members are represented by a plane two-dimensional figure. It can be seen that the curved unit <NUM> is provided with flexible seal members <NUM> of the first type along one long side <NUM> (that is extending over the curve of the curved panel) It will be recalled that the first flexible seal member comprises a surface component <NUM> extending over the surface <NUM> of the concrete from one, or preferably from between two anchor components, (not visible) embedded in the concrete of the curved panel, and an overlap component <NUM> extending beyond the perimeter <NUM> of the concrete curved panel. The two short sides <NUM> and <NUM> (that is the two base ends of the curved panel) are provided with wide flexible seal members of the second type, with the remaining opposite long side <NUM> (that is extending over the curve of the panel) also provided with a second flexible seal member <NUM>. Again it will be recalled that is a second flexible seal member comprises a surface component <NUM> extending over the surface <NUM> of the concrete from at least one, preferably two, embedded anchor components (not visible). The flexible seal members <NUM> and <NUM> form a continuous seal by mitering and welding at the intersecting comers.

In use, as shown in <FIG>, the overlap component <NUM> of a first flexible seal member projecting from the curved edge of a first curved panel, overlaps the surface component along the curved edge of an adjoining curved panel and is heat welded to the surface component. In the arrangement of <FIG> (and as best seen in the enlargement of <FIG>), the ends of the curved panels <NUM> may be sealed into the channel <NUM> of the base slab <NUM> by means of a sealing compound firstly placed in the channel.

Alternatively, as also shown in the detailed view of <FIG>, separate flashing strips <NUM> maybe welded both to the surface component of the flexible second seal members <NUM> at the ends of the curved panel, and to the surface component <NUM> of the flexible seal member provided along the outer ledges <NUM> of the channels <NUM> as explained above. Thus the tunnel panels <NUM> are completely sealed panel to panel and to the base slab <NUM>.

In an alternative arrangement of a tunnel sealed with the seal system of the invention, a tunnel <NUM> as shown in <FIG>, in this instance is formed of curved panels made up of pairs of cooperating curved panels <NUM> and <NUM>. The lower ends of the curved panels <NUM>,<NUM> are again located in a similar base slab <NUM> provided with channels as described above. The joint at the upper ends of the curved panels <NUM>,<NUM> may be arranged variously, for example as a stepped joint <NUM> or with a key block <NUM> as shown in the enlargements of <FIG> and <FIG>.

In this arrangement in which each arch unit comprises a pair of curved panels <NUM>, <NUM>, the pairs are arranged with flexible seals as shown in <FIG>. Again, one long side of each panel is provided with a first flexible seal member <NUM> while the opposite long side is provided with a second flexible seal member. In this instance one of the pair of panels (say <NUM>) is provide at its lower channel-seating end <NUM> with a second flexible seal member <NUM> but at its upper, jointing end, with a first flexible seal member 822A. The other panel of the pair (thus <NUM>) is provided with flexible seal members in the same configuration as the panels of the single panel arches <NUM> and shown in <FIG>. The method of sealing of the tunnel <NUM> is similar to that of the previously described tunnel <NUM> in every respect except that the sealing of the joint between the upper ends of a panel <NUM> and a panel <NUM> is now achieved by the overlap component of the first flexible seal member 822A of panel <NUM> being heat welded to the surface component of second flexible seal member 840A. In the case of the panels <NUM> and <NUM> being joined via a key block <NUM>, the overlap component of flexible seal member 822A is simply increased in width to cover the joints at either side of the key block.

As illustrated in cross section in <FIG>, the concept may be applied to either single piece arches, two piece arches or two piece and coupling-type arches.

Arrangements of the invention as discussed above may be applied with advantage to concrete tank reservoirs and also to concrete building structures where the concrete construction may be either of the pre-cast or in situ type.

In one further arrangement of the seal system according to the invention, the system may be applied to bund walls for dams. In this instance the bund walls may be formed of vertical concrete panels as described above. Sealing between the panels is provided with the same first and second flexible seal members arranged at the edges of adjoining panels.

Claim 1:
A flexible seal system (<NUM>) for provision of a substantially watertight seal between adjacent concrete panels (<NUM>, <NUM>); said system comprising
a first flexible seal member (<NUM>) locatable proximate a first end (<NUM>) of one said concrete panel (<NUM>); said first flexible seal member (<NUM>) including:
at least one anchor component (15A);
a surface component (<NUM>) suitable for overlaying a portion of an outer surface of said concrete panel (<NUM>); said surface component (<NUM>) extending from said at least one anchor component (15A) which is projecting from said surface component (<NUM>) and which is suitable to be embedded within said concrete panel (<NUM>);
a second flexible seal member (<NUM>) locatable proximate a second opposite end (<NUM>) of an abutting said concrete panel (<NUM>); said second flexible seal member (<NUM>) including;
- at least one anchor component (19A);
- a surface component (<NUM>) suitable for overlaying a portion of an outer surface (<NUM>) of said abutting concrete panel (<NUM>); said surface component (<NUM>) of said second flexible seal member (<NUM>) extending from said at least one anchor component (19A), which is projecting from said surface component (<NUM>) and which is suitable to be embedded within said abutting concrete panel (<NUM>);
characterized in that the surface component (<NUM>) of said first flexible seal member (<NUM>) extends integrally to an overlap component (<NUM>) said overlap component (<NUM>) suitable for extending beyond said first end (<NUM>) of said concrete panel (<NUM>),
wherein the overlap component (<NUM>) of the first flexible seal member (<NUM>) is structured and selected in use to overlap the surface component (<NUM>) of the second flexible seal member (<NUM>) sufficient to permit welding of at least a portion of said overlap component (<NUM>) of said first flexible seal member (<NUM>) to at least a portion of said surface component (<NUM>) of said second flexible seal member (<NUM>) so as to form a continuous welded seal (<NUM>) between and along the length of said first flexible seal member (<NUM>) and said second flexible seal member (<NUM>).