Patent Description:
Shoring systems are constructed to retain earth and the adjacent structures when a bulk excavation is required. Traditionally, a shoring system comprises piles inserted vertically into the ground at the design spacing around the exterior of the perimeter of a new structure. The area in front and between the piles is excavated in increments (maximum <NUM> meters), which is a time consuming and difficult task. As excavation progresses the piles can be reinforced by bracing with temporary anchors and installing steel dowels between the piles before creating a shotcrete wall interface (see <FIG>).

Ensuring that permanent underground wall structures and floors remain watertight is not a trivial task. Several methods have been used including; constructing a concrete block wall in front of the piles from the basement up to the ground level, to "hide from view" the water leakages and the uneven surface of the piles and the shotcrete walls. In addition, a vertical geosynthetic drainage strip material can be attached to the rear side of the reinforcing steel dowels prior to shotcreting to provide a direct flow of passage of seepage to the basement prior to pumping it out. In the case where the ground has a particularly high water table, a secant piles wall may be used to provide the tanking of the underground structure.

discloses the use of precast concrete panels to build a wall in a shoring-free excavation and basement construction apparatus and method. The concrete panels in <CIT> are moulded with a parabolic cross section and lateral faces of the panels are attached between the piles-columns using a bolt system. The bolt system comprises a bolt through the metal post to a steel plate bonded to the backside of the concrete panel. The bolt mechanism acts to prevent the panel from any downward movement during the excavation process. This system does not allow any tolerance on the installation of the columns / soldier piles and requires the soil/earth between the piles-columns to be excavated.

<CIT> discloses a method of constructing an underground building structure without the use of a conventional shoring system. The shoring method requires inserting columns into the ground and vertically arranging concrete or shoring panels against the exterior wall columns. Thus the panels vertically exert force on the ground whilst being reinforced with temporary braces. In this technique the panels are not permanently bolted in place.

<CIT> discloses an excavation perimeter surface lining system and method according to the preamble of claims <NUM> and <NUM>, respectively.

<CIT> discloses a rigid connection system for adjustably connecting facing panels to soldier piles so as to support the cut face of an excavation, said system comprising: a first rigid bracket coupled to the rear face of a facing panel; a second rigid bracket coupled to the front face of a soldier pile substantially opposite said first bracket; at least one rigid connecting plate coupled between said first bracket and said second bracket, and adjustment means provided by said first bracket, said second bracket and said rigid connecting plate for providing three degrees of adjustment between said soldier pile and said facing panel.

Some of the main disadvantages of the traditional shoring method using piles and shotcrete walls are time consuming steps including excavating the earth between the piles and the additional supply and installation of dowel bars. Furthermore, shotcreting is not only time-consuming but also extremely sensitive to inclement weather. The traditional shoring method cannot provide waterproofed walls and strip drains are difficult to install and most of the time inefficient. Generally, the construction of an additional concrete block wall in front of the piles is required to overcome these problems. Overall, the construction of underground structures is a long and complex activity, that is expensive and requires the expertise of tradesmen in areas such as: diggers, steel fixers, shotcreters and brick layers.

It would be advantageous if a system and method could be provided which did not require the participation of multiple trades and yet provided for a means of shoring, even in unstable or water laden ground. It would be further advantageous in at least some forms to provide a waterproofing seal at the soldier pile interface. It would be further advantageous if a system and method could be provided which did not require the construction of additional facades in order to provide a finished, functional lining for the perimeter surface of an excavation.

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.

Accordingly, in one broad form of the invention, there is provided an excavation perimeter surface lining system for lining a perimeter surface of an excavation; the perimeter surface defined by a solid structure; characterized in that the perimeter surface lined by means of precast concrete panels which are affixed to the solid structure; wherein the solid structure is a rock face; wherein the solid structure comprises a plurality of columns; wherein the precast concrete panels are affixed to a front portion of the columns; wherein material in the volume between the columns is not excavated; wherein the precast concrete panels are arranged with their edges in a juxtaposed relationship; wherein the precast concrete panels adjoin at a location between the columns; wherein the precast concrete panels adjoin vertically; where the precast concrete panels adjoin horizontally; wherein the columns are substantially parallel to each other; and wherein the concrete panels are arranged in juxtaposed relationship such that an overlap component of a flexible seal member of a first type overlaps at least a portion of a surface component of a flexible seal member of a second type so as to form an elongated weld zone along edges of the juxtaposed concrete panels; and wherein a welding operation is performed along the length of the elongated weld zone whereby the overlap component of the flexible seal member of the first type is welded to the flexible seal member of the second type substantially along the elongated weld zone thereby to form a substantially water tight flexible seal between the juxtaposed concrete panels; and wherein the overlap component of the overlap components of the flexible seal members proximate the vertical edge of first and second vertical concrete panels are welded.

Accordingly, in another broad form of the invention, there is provided an excavation perimeter surface lining method for lining a perimeter surface of an excavation; the perimeter surface defined by a solid structure; characterized in that the perimeter surface lined by means of precast concrete panels which are affixed to the solid structure ; and wherein the solid structure is a rock face; and wherein the solid structure comprises a plurality of columns; and wherein the precast concrete panels are affixed to a front portion of the columns; and wherein material in the volume between the columns is not excavated; and wherein the precast concrete panels are arranged with their edges in a juxtaposed relationship; and wherein the precast concrete panels adjoin at a location between the columns; and wherein the precast concrete panels adjoin vertically; and wherein the precast concrete panels adjoin horizontally; and wherein the columns are substantially parallel to each other; and wherein the concrete panels are arranged in juxtaposed relationship such that an overlap component of a flexible seal member of a first type overlaps at least a portion of a surface component of a flexible seal member of a second type so as to form an elongated weld zone along edges of the juxtaposed concrete panels; and wherein a welding operation is performed along the length of the elongated weld zone whereby the overlap component of the flexible seal member of the first type is welded to the flexible seal member of the second type substantially along the elongated weld zone thereby to form a substantially water tight flexible seal between the juxtaposed concrete panels; and wherein the overlap component of the overlap components of the flexible seal members proximate the vertical edge of first and second vertical concrete panels are welded.

Accordingly, in another broad form of the invention there is provided a system for lining a perimeter surface of an excavation; the perimeter surface defined by a solid structure; the perimeter surface lined by means of precast concrete panels which are affixed to the solid structure.

Accordingly, in a further broad form of the invention there is provided a system for lining a perimeter vertical and horizontal surface of an excavation for the purpose of waterproof tanking including the base floor area; the perimeter surface defined by a solid structure; the perimeter surface lined by means of precast concrete panels which are affixed to the solid structure.

Accordingly, in a further broad form of the invention there is provided a method for lining a perimeter surface of an excavation; the perimeter surface defined by a solid structure; the perimeter surface lined by means of precast concrete panels which are affixed to the solid structure.

Preferably the perimeter surface is a vertical surface.

Preferably the perimeter surface is a horizontal surface.

Accordingly, in yet a further broad form of the invention there is provided a top-down method of affixing precast concrete panels to piles; said method including the steps of:.

Accordingly, in yet a further broad form of the invention there is provided a bottom-up method for the construction of an underground structure can be used subsequent to the completion of the formation level of the precast concrete panel system affixed to piles; said method including the steps of:.

Accordingly, in yet a further broad form of the invention there is provided a top-down method of affixing precast concrete panels to a rock face; said method including the steps of:.

Accordingly, in yet a further broad form of the invention there is provided a bottom-up method for the construction of the underground structure can be used subsequent to the completion of the formation level of the precast concrete panel system affixed to rock a face; said method including the steps of:.

Accordingly, in yet a further broad form of the invention there is provided a top-down method of affixing precast concrete panels to canopy tubes; said method including the steps of:.

Preferably the solid structure is a rock face.

Preferably the solid structure comprises a plurality of columns.

Preferably the precast concrete panels are affixed to a front portion of the columns.

Preferably the material in the volume between the columns is not excavated.

Preferably the precast concrete panels are arranged with their edges in a juxtaposed relationship.

Preferably an expansion seal, gasket or wall seal system (as described further in this patent application) can be utilized to seal between the adjacent precast concrete panels.

Preferably the precast concrete panels adjoin at a location between the columns.

Preferably the precast concrete panels adjoin vertically.

Preferably the precast concrete panels adjoin horizontally.

Preferably the columns are substantially parallel to each other.

Preferably the piles comprise soldier piles.

Preferably the piles comprise of contiguous piles.

Preferably the piles comprise of secant piles.

Preferably the piles are comprised of reinforced concrete.

Preferably each pile of the piles is formed by the step of drilling so as to define a tubular cavity followed by the step of inserting reinforcement material into the tubular cavity followed by the step of pouring concrete into the tubular cavity and allowing it to set thereby to construct the pile.

Preferably the columns comprise canopy tubes.

Preferably the canopy tubes are filled with grout.

Preferably the perimeter surface is substantially planar.

Preferably the perimeter surface is substantially curved.

Preferably the precast concrete panels are comprised of steel and/or fibre reinforced concrete.

Preferably the precast concrete panels are cast in a mould.

Preferably the precast concrete panels are cast with a fully covering vertical drainage structure void HDPE mesh.

In a preferred form the mesh is covered both sides with a geotextile being a composite material that is adhered to the reverse side of the precast concrete panels.

Preferably the reverse side of the precast concrete panels comprising said fully covering vertical drainage structure void HDPE mesh.

In a preferred form the mesh is covered both sides with a geotextile being a composite material that is positioned against the solid structure to which the precast concrete panels are affixed.

Preferably the precast concrete panels are cast with an encapsulated flexible seal member extending from at least one edge of the precast concrete panels.

Preferably the precast concrete panels are affixed to the solid structure by means of rock bolts.

Preferably the precast concrete panels are affixed to the solid structure by means of chemical bolts.

Preferably the precast concrete panels are affixed to the solid structure by means of mechanical bolts.

Preferably the precast concrete panels are affixed in a first step by means of anchors extending beyond the perimeter surface into material located behind the perimeter surface.

Preferably the anchors are deactivated after alternative support structures are implemented.

Preferably the anchors are deactivated after the basement floors are built.

Preferably excavation occurs at a maximum of <NUM> metre increments.

Preferably if tanking of the underground structure is required, install the precast concrete panels horizontally on the lowest basement and vertically on the perimeter of the structure.

Preferably there is a further step of sealing all joints between adjacent panels.

Preferably sealing is performed utilising overlapping seals, expansion seal, gasket or the wall seal system as described further in this application.

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

Embodiments of the present invention are concerned with the use of precast concrete panels affixed to solid structures to form the interior walls or linings of excavations such as tunnels or underground structures which may be in the form of car parks, train stations and containment cells for contaminated materials. In one form components of the system may be used to form a shoring system to facilitate formation of the excavations.

With reference to <FIG>, there is illustrated a plan view of a first embodiment of the present invention where the solid structures in this instance comprise vertical piles <NUM>.

In this preferred embodiment, the excavation is built utilizing a precast concrete panel system <NUM> in this instance by way of a top-down construction method. Once the formation of the excavation has been achieved, the construction of the underground structure can start using a bottom-up method.

In the first embodiment of the precast concrete panels system <NUM> piles <NUM> are inserted into the ground at a horizontal spacing <NUM> around the exterior perimeter <NUM> of the underground structure <NUM> to be formed. In preferred forms the horizontal spacing <NUM> between the piles is calculated preferably using the vertical loads and the side loads exerted on the piles. A typical, non-limiting spacing is approximately <NUM> - <NUM> metres.

With reference to <FIG>, in the first preferred embodiment, the material directly in front of the piles <NUM> may be excavated in vertical increments <NUM> (preferably maximum <NUM> metres) to avoid ground collapse. At each excavated vertical increment <NUM>, the rectangular precast concrete panels <NUM> are affixed, in this instance, to the front portion of two or more piles <NUM>. In a preferred form the precast concrete panels <NUM> are oriented with their longest dimension parallel to the ground. In another form the precast concrete panels <NUM> may include decorative features. In one form these features may include relief patterns.

With reference to <FIG>, the preferred juxtaposed relationship between precast concrete panels <NUM> ensures that they vertically adjoin at a region <NUM> located intermediate the piles. In a preferred form there may be a gap, for example of up to <NUM>, between adjacent precast concrete panels. In this embodiment the region <NUM> at no stage is located flush with the front <NUM> of the piles <NUM>.

In this instance the preferred method of affixing the precast concrete panels to the piles <NUM> is by means of bolts <NUM> passing through the precast concrete panels <NUM> and into the piles <NUM>. In a particular preferred form, a minimum of <NUM> bolts <NUM> is utilised to affix each precast concrete panel <NUM> to piles <NUM>.

In a preferred embodiment, a temporary anchor <NUM> is inserted through a steel plate <NUM> and driven at an angle into a precast concrete panel <NUM>. In a preferred form the temporary anchor <NUM> passes through the precast concrete panel <NUM> and then through the soldier pile <NUM> to which the precast concrete panel is abutted. The temporary anchor <NUM> then extends into the material <NUM> located behind the perimeter surface <NUM> (see <FIG>) thereby to anchor the precast concrete panels <NUM> into the material <NUM>. There remains a portion of the temporary anchor <NUM> which protrudes at an angle from the surface of the wall <NUM>. This arrangement provides at least temporary bracing or shoring of the precast concrete panels <NUM> pending utilisation of alternative forms of bracing or shoring.

In a preferred embodiment, the basement slabs <NUM> may form the floor of each respective level. The slabs <NUM> are installed sequentially from the lowest level up. The floors provide the required bracing or shoring for the precast concrete panel system <NUM>. As each floor is installed the relevant temporary anchor <NUM> may be destressed and the anchor plates <NUM> and protruding section of the temporary anchor <NUM> removed.

In a preferred embodiment, the precast concrete panels <NUM> are cast with a fully covering vertical drainage structure <NUM> on the reverse side. The vertical drainage structure <NUM> includes either a bi-dimensional or tri-dimensional HDPE mesh void structure, encapsulated by a geotextile fabric. The vertical drainage structure <NUM> may function as a conveyance passage for water and/or gas emissions. In addition, or in the alternative it may be used as a thermal and/or noise insulator.

With reference to <FIG> and <FIG> and <FIG> there is illustrated a second preferred embodiment of the present precast concrete panel system <NUM> wherein the gaps between the affixed precast concrete panels <NUM> are sealed using a flexible seal system for provision of a substantially watertight seal between adjacent concrete panels.

In a preferred embodiment the precast concrete panels are cast with an encapsulated flexible seal member extending from at least one edge of the precast concrete panels.

In this second preferred embodiment the precast concrete panels are constructed from a method comprising pouring concrete into formers moulds; suspending flexible seal members into the concrete prior to its setting such that at least the anchor portion of the flexible seal member is encased within the concrete; The concrete then sets to form a solid concrete panel having one or more flexible seal members anchored therein.

The concrete panels are arranged in juxtaposed relationship such that an overlap component of a flexible seal member of a first type overlaps at least a portion of a surface component of a flexible seal member of a second type so as to form an elongated weld zone along edges of the juxtaposed concrete panels. A welding operation is performed along the length of the elongated weld zone whereby the overlap component of the flexible seal member of the first type is welded to the flexible seal member of the second type substantially along the elongated weld zone thereby to form a substantially water tight flexible seal between the juxtaposed concrete panels. The overlap component of the overlap components of the flexible seal members proximate the vertical edge of first and second vertical concrete panels are welded. Panels may be stacked on the longitudinal alignment of panels.

With reference to inset <FIG> one particular form of the wall seal system comprises an F shaped membrane <NUM> having an overlap component 130A is anchored into precast concrete panel <NUM> by means of anchor component 130B. The overlap component 130A is dimensioned so as to, in use, overlay an external portion of C shaped membrane <NUM> and to which it is subsequently welded by double weld <NUM>. The C shaped membrane is anchored into the adjacent panel <NUM> by means of anchor components 131B.

In this instance a tongue in groove or male/female joint <NUM> is utilised to position and retain adjacent precast concrete panels <NUM> in juxtaposed relationship.

In one form the precast concrete panels <NUM> are fixed in a manner to suit the construction sequence of the underground structure and seek to avoid the male-female interlocking joints <NUM> from interfering with basement slabs <NUM> and walls.

In an instance where the ground water table is very high partial or full tanking of the underground structure may be required. In this case the lowest basement is built using the precast concrete panels <NUM> placed horizontally. The joints <NUM> between the precast concrete panels may be waterproofed using the Wall Seal System <NUM>.

Further examples of the wall seal system <NUM> which may be applied to any of the described above embodiments, are described later in this specification.

In the precast concrete panels system <NUM> shown in <FIG> the solid structure illustrated comprises piles <NUM> arranged in soldier pile format. In a further preferred embodiment the horizontal spacing between the piles <NUM> becomes negligible and the solid structure takes the form of contiguous piles <NUM>. A plan view of such an arrangement is shown in <FIG>. The precast concrete panels <NUM> may then be affixed directly to the front region <NUM> of the contiguous piles in a juxtaposed relationship. In preferred forms the gaps between the affixed precast concrete panels <NUM> are sealed using sealing material. In a particular preferred form, a flexible seal system (as described elsewhere in the specification) for provision of a substantially watertight seal between adjacent concrete panels may be adopted. In this instance the fully covering vertical drainage structure void HDPE mesh adhered to the reverse side of the precast concrete panels acts as a drainage system between the contiguous piles and the inner wall.

In the precast concrete panels system <NUM> shown in <FIG> the solid structure illustrated is piles <NUM>. In a further preferred embodiment, where the material <NUM> has a high water table, the piles <NUM> may be cast such that they are interlocked and the solid structure takes the form of secant piles (see <FIG>). The construction of secant piles involves casting primary (female) piles <NUM> first with secondary (male) piles <NUM>, cutting into the primary piles forming a continuous wall. In one form the primary and secondary piles may be cast from different concrete. In this instance the fully covering vertical drainage structure void HDPE mesh adhered to the reverse side of the precast concrete panels acts as the drainage system between the piles and the inner wall.

With reference to <FIG> there is illustrated a third preferred embodiment of the present precast concrete panel system <NUM> wherein precast concrete panels <NUM> are affixed directly to a rock face <NUM> to line the perimeter surface <NUM> of an excavation <NUM> in this instance defined substantially by the rock face <NUM>.

In this embodiment, particularly where the perimeter surface <NUM> of an excavation is too dense to insert any additional solid fixtures, the precast concrete panels <NUM> may be directly affixed to the rock face <NUM> or rocky ground. In this instance, the preferred method of affixing the precast concrete panels to the rock face <NUM> is by means of rock bolts <NUM> passing through the precast concrete panel <NUM> and into the rock face <NUM>. In this instance, no temporary anchor bolts are required. In a preferred form, the rock bolts <NUM> are used to support the panels <NUM> in place on a permanent basis.

With reference to <FIG>, there is illustrated a fourth embodiment of the present precast concrete panel system <NUM> wherein curved precast concrete panels <NUM> are affixed to canopy tubes <NUM>, to line the perimeter surface <NUM> of an arch formation <NUM>.

In the fourth preferred embodiment hollow canopy tubes <NUM> are driven into material <NUM> at a distance slightly higher than the perimeter surface <NUM> of the intended arch formation <NUM>. The canopy tubes <NUM> are filled with grout <NUM> and the material <NUM> directly below is excavated in increments. The curved precast concrete panels <NUM> are affixed to the grout filled canopy tubes, in this instance using stainless steel bolts <NUM>, as the excavation progresses.

In a preferred embodiment, the curved precast concrete panels <NUM> may include on the reverse side a fully covered drainage structure which in a preferred form comprises of a biplanar or tri-planar HDPE mesh void structure encapsulated by a geotextile fabric <NUM>. Adjacent curved precast panels <NUM> may be joined using the flexible seal system <NUM> described earlier. In preferred forms the flexible seal system <NUM> acts to form a waterproof joint between adjacent panels <NUM>.

With reference to <FIG>, there is illustrated a perspective view of an alternative embodiment for sealing the reverse side of adjacent precast concrete panels. The precast concrete panel <NUM> is defined by surface edges <NUM>. In this instance the perimeter of the precast concrete panel <NUM> near the surface edge <NUM> is rimmed with a conductor, preferably copper wire positioned beneath a layer of the flexible seal system <NUM>. A through channel <NUM> is formed communicating from the front side 122A to the reverse side of the precast concrete panel <NUM>. The edges <NUM> of two adjacent precast concrete panels <NUM> may be sealed by electrofusion welding by means of heating the copper wire <NUM> using the through channel <NUM> to establish an electrical connection with the copper wire on the reverse side of the precast concrete panel <NUM>. In a particular preferred form electro conductive welding is utilised to weld both the front layers of the flexible seal system and the reverse side layers of the panels <NUM> thereby providing a double seal.

With reference to <FIG>, there is illustrated a perspective view of a further embodiment of a precast concrete panel <NUM> incorporating cavities <NUM>. The cavities <NUM> in this instance comprise hollowed out passages through the precast concrete panel from one surface edge <NUM> to another. These cavities <NUM> can be used to house services such as electrical and communication cables thereby to facilitate the enclosed transportation of services around the perimeter of the underground structure <NUM>.

The flexible seal system <NUM> described above may take a number of forms when used to assist in sealing any of the above described embodiments. Further examples of the flexible seal system are described below and with reference to <FIG>.

The flexible seal system is 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> mm x <NUM> or as large as <NUM> x <NUM> mm 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 further 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 further embodiment of a flexible seal system <NUM> where like components are numbered as for the 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.

The wall panel arrangement of <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 of any previous embodiments including those of <FIG> 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 a further preferred embodiment of the invention, 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>.

Claim 1:
An excavation perimeter surface lining system for lining a perimeter surface (<NUM>) of an excavation (<NUM>); the perimeter surface (<NUM>) defined by a solid structure (<NUM>; <NUM>); characterized in that the perimeter surface lined by means of precast concrete panels (<NUM>; <NUM>) which are affixed to the solid structure (<NUM>; <NUM>); wherein the solid structure (<NUM>; <NUM>) is a rock face (<NUM>); wherein the solid structure comprises a plurality of columns (<NUM>); wherein the precast concrete panels (<NUM>; <NUM>) are affixed to a front portion of the columns (<NUM>); wherein material in the volume between the columns (<NUM>) is not excavated; wherein the precast concrete panels (<NUM>; <NUM>) are arranged with their edges in a juxtaposed relationship; wherein the precast concrete panels (<NUM>; <NUM>) adjoin at a location (<NUM>) between the columns (<NUM>); wherein the precast concrete panels (<NUM>; <NUM>) adjoin vertically; where the precast concrete panels (<NUM>; <NUM>) adjoin horizontally; wherein the columns (<NUM>) are substantially parallel to each other; and wherein the concrete panels (<NUM>; <NUM>) are arranged in juxtaposed relationship such that an overlap component of a flexible seal member of a first type overlaps at least a portion of a surface component of a flexible seal member of a second type so as to form an elongated weld zone along edges of the juxtaposed concrete panels; and wherein a welding operation is performed along the length of the elongated weld zone whereby the overlap component of the flexible seal member of the first type is welded to the flexible seal member of the second type substantially along the elongated weld zone thereby to form a substantially water tight flexible seal between the juxtaposed concrete panels; and wherein the overlap component of the overlap components of the flexible seal members proximate the vertical edge of first and second vertical concrete panels are welded.