AU2010201761A1 - Wall panel and installation thereof - Google Patents

Description

Our Ref: 4580AU P/00/009 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ENTITLED Invention title: Wall panel and installation thereof Name of Applicant: Clayton Smyth Address for Service A.P.T. Patent and Trade Mark Attorneys PO Box 222 Mitcham, S.A. 5062 The invention is described in the following statement 2 Wall panel and installation thereof FIELD OF THE INVENTION The present invention relates to modular walls and in one particular aspect relates to a precast concrete modular retaining wall that includes a plurality of wall 5 panels each being attached at one end to a respective concrete pier and being supported at the opposing end by an adjacent wall panel. In another aspect the invention relates to a fence or wall panel in general that is supported at one end by a subterranean concrete pier and at the other end by an adjacent panel. BACKGROUND OF THE INVENTION 10 Retaining walls are used extensively in construction and garden landscaping to provide support for earth and backfill. Retaining walls inhibit downslope movement or erosion and provide support for vertical or near-vertical grade changes. Typically retaining walls are constructed from masonry, stone, brick, concrete, steel or timber. Railway sleepers have in the past been a popular way of 15 constructing retaining walls. However due to the risks associated with termite activity these have become less popular. Interlocking blocks and concrete sleepers are useful for low retaining walls. However for walls over 1 meter these types of retaining wall members can become quite expensive. Prefabricated reinforced panel retaining walls are typically used for larger 20 walls since they are cheaper and quicker to install. One such retaining wall system involves the digging of a trench and placement of rectangular prefabricated panels in an upright position within the trench. The trench is then backfilled and the portion of panel below the ground helps to support the wall in an upright position. The prefabricated panels must be positioned at least 5mm apart to provide an expansion 25 joint for the concrete panels to compensate for expansion of the material due to temperature. This exposed gap is normally filled with a silicon material to prevent soil movement through the gap. Such exposed expansion joints can be unsightly and the silicon filler tends to break down over time. A similar type of retaining wall is the cantilever wall that has an L-shaped, or 30 inverted T-shaped, cross sectional profile The downward weight of the soil on the horizontal wing helps to maintain the wall in an upright position. The limitation with 3 both these types of walls is that a significant portion of the reinforced concrete is below the surface of the ground which adds to the overall cost of the retaining wall. A popular type of retaining wall currently used involves the attachment of prefabricated panels to prepared posts. Typically a lower portion of a length of H 5 section or C-section steel post is inserted into postholes at predetermined distances and concrete is poured into the holes to fix the posts in place. The panels are then positioned between the upper portion of adjacent posts. One of the difficulties with these types of systems is that the distance between the posts has to be quite accurate to ensure that the prefabricated panels can be slidably accommodated 10 between adjacent posts. Any variation greater than around 40mm can significantly affect the wall structure. Furthermore if a post is incorrectly positioned at an angle to the vertical the person installing the panel between the posts may encounter problems. Currently available retaining wall and fence systems suffer from various 15 deficiencies and it is an object of the present invention to substantially overcome or at least ameliorate one or more of the disadvantages of the prior art. It should be appreciated that any discussion of the prior art throughout the specification is included solely for the purpose of providing a context for the present invention and should in no way be considered as an admission that such prior art 20 was widely known or formed part of the common general knowledge in the field as it existed before the priority date of the application. SUMMARY OF THE INVENTION In one aspect of the invention but not necessarily the broadest or only aspect, there is proposed a retaining wall including a plurality of wall panels each having a 25 fixable end for attachment to a support member and an opposing free end for engagement with a first adjacent wall panel, said fixable end including an engagement means for engagement with a free end of a second adjacent wall panel, wherein the free ends of the plurality of wall panels are urged against the engagement means of adjacent wall panels by the pressure of the material held 30 behind said retaining wall. Each said plurality of wall panels being coupled at said fixable end to a respective support member, and said opposing free end being supported by the 4 coupled fixable end of an adjacent wall panel. This means that each wall panel provides support for the free end of an adjacent wall panel and is itself supported at its free end by another adjacent wall panel. The fixable end of said panel may include an attachment means for 5 attachment to the support member. In one form the attachment means may be a depending coupling, the coupling being used to connect a reinforcement means of the wall panel with a reinforcement means of said support member. The support member is preferably a substantially subterranean concrete pier 10 support. Each wall panel preferably includes a generally planar rectangular body and a forwardly extending pillar at said fixable end. The rectangular body having a front face, generally parallel top and bottom edges, and perpendicular, generally parallel, first and second sides extending therein between. The first side being located at the 15 fixable end of the panel and the second side being located at the free end of the panel. The forwardly extending pillar may be configured to retain a reinforcement means and the attachment means in the form of a depending coupling. The coupling is used to connect the reinforcement means of the wall panel with a reinforcement 20 means of the support member. In one form the engagement means may be a lip being stepped into the rear of the wall panel and extending down the length of the first side, the lip including a generally planar shoulder surface perpendicular to a generally planar side surface thereby forming a recessed corner for engagement with the generally right angle 25 edge of the free end of an adjacent wall panel. The shoulder surface of said lip may be between 50-300mm and is preferably 100mm wide and side surface of said lip may be between 50-300mm and is preferably 100mm wide. In one form the shoulder surface of said lip may be parallel to a front face of the rectangular body and the lip being positioned along a vertical 30 edge of the fixable end of the wall panel wherein when adjacent wall panels are installed the respective planar rectangular bodies are substantially coplanar.

5 In an alternate form the shoulder surface of said lip extends rearwardly or forwardly at an angle to said front face of the rectangular body wherein when adjacent wall panels are installed the respective planar rectangular bodies are at an angle relative to the vertical plane. In this way various shaped walls, such as curved 5 retaining walls, can be constructed. Adjacent panels are preferably separated by a gap of between 2-10mm and preferably 5mm to provide an expansion joint to compensate for any expansion in the material from which the wall panels are constructed. The expansion joints prevent development of lateral compression between adjacent concrete panels. The 10 expansion joint is hidden from view behind the pillar. Which provides aesthetic benefits as well as inhibiting movement of soil because the front of the free end of a wall panel bears against the front shoulder of the lip of an adjacent panel. In one form the wall panels are constructed from prefabricated reinforced concrete. It should however be appreciated that other types of material could be 15 used in forming the wall panels. The prefabricated concrete panels may include a plurality of reinforcement bars in the form of a lattice, the bars being preferably constructed from steel. The reinforcement may be deformed reinforcement in the form of metal bars, wire, or fabric with a manufactured pattern of surface ridges that provide a locking 20 anchorage with surrounding concrete. Alternatively plain bars and wire mesh may also be used. The generally subterranean concrete piers may includes a plurality of reinforcement bars preferably constructed from steel. Where the wall panel is 1.2m in height the pier is preferably founded between 1.8-2m into original undisturbed hard 25 silty clay. Preferably the subterranean concrete piers are substantially post-pour piers, in that the panels are positioned with respect to previously excavated holes. The panels are located in position using temporary stays and the reinforcement for the piers is attached to the underside of the panel such that the reinforcement extends 30 down into the excavated hole. The concrete is then poured into the hole and allowed to cure before the temporary stays are removed.

6 At least some of the steel reinforcement bars of said prefabricated concrete panel are preferably connected to the steel reinforcement bars of said concrete pier. In one form each panel includes two couplings for engagement with the reinforcement of the pier. At least one of said reinforcement bars may include a 5 threaded portion for engagement with a threaded coupling. In one form the threaded coupling is attached to the reinforcement prior to pouring concrete into a mould to form the wall panel. The reinforcement is supported within the mould on plastic stools or mortar blocks of equal strength and durability to the concrete mix, ensuring that there is a 40mm clear concrete cover over all the 10 reinforcement excluding the couplings. In this way an open end of the coupling can be positioned so that it is flush with the external bottom surface of the wall panel. This means that a threaded reinforcement bar can be attached to the end of the coupling that itself is attached to a reinforcement bar contained within the prefabricated concrete wall panel. 15 Therefore the prefabricated concrete panels do not include reinforcement bars protruding outwardly, since this may cause difficulties during transport. In one form a steel C-section post may be used at one end of the retaining wall to support the free end of a first wall panel that is not supported by an adjacent wall panel. Alternatively the first wall panel located at an end of the retaining wall 20 may have a pillar at each end of the planar body so that both ends of the wall panel can be attached to respective support members. In another form the free end of the wall panel may engage a registry means attached to an existing wall or fixed structure. In another aspect of the invention there is proposed a method of constructing 25 a retaining wall including a plurality of wall panels, including the steps of: excavating a series of pier support holes at known distances; positioning a plurality of wall panels, each having a generally planar body, a fixable end and an opposing free end, wherein the fixable end of each wall panel is positioned over a corresponding excavated hole and the free end of each wall panel 30 positively registers with an engagement means of an adjacent wall panel; attaching the fixable end of each wall panel to a support member located within said excavated hole; and pouring a flowable concrete mixture into said excavated pier support holes to thereby form substantially subterranean concrete piers.

7 In use pier support holes are excavated prior to placement of the wall panels. The holes are dug at predetermined positioned to correspond to the calculated location of the pillars of said wall panels. The pier support holes would be around 2100mm apart for use on wall panels that are 2450mm in length. 5 Preferably the fixable end includes a pillar that partially accommodates depending couplings. The wall panels are positioned in an upright array such that an exposed end of the depending couplings are located above the prepared holes. Once in position the wall panels are supported with temporary stays. Main reinforcement bars can then be lowered into the excavated hole and attached to the 10 exposed end of the depending couplings. In one form additional reinforcement is suspending in the hole and connected to the main reinforcement bars using steel ligatures. The excavated holes are preferably 350mm in diameter and between 1.8 2m deep. In one form the additional reinforcement are two lengths of 12mm steel rod 15 and main reinforcement bars are two lengths of 20mm rod sold under the trade mark REIDBAR@. The wall panel includes two lengths of 20mm rod sold under the trade mark REIDBAR@ attached to REIDBAR@ couplers. It should be appreciated that other types of couplers could be used including the product sold under the trade mark MonkeyBar@. Alternatively the pier reinforcement could be chemset into the 20 underside of the wall panel using an appropriate epoxy mortar. A flowable concrete mixture is then poured into the hole and allowed to cure. The concrete is compacted by immersed mechanical vibrators. Drainage or Ag pipe is placed behind the wall and is overlaid with a 100mm wide column of gravel to reduce hydrostatic pressure, as is well known in the art. The temporary stays can 25 then be removed and soil or rocks backfilled in behind the retaining wall. The backfill acts to hold the free ends of each wall panel against the engagement means of an adjacent wall panel. In yet another aspect of the invention there is proposed a wall panel including a fixable end for attachment to a support member and a free end for engagement 30 with a first adjacent wall panel, wherein said fixable end includes an engagement means for engagement with a free end of a second adjacent wall panel.

8 In still yet a further aspect of the invention there is proposed a wall, fence, barricade or partition panel including a support end for connection to a subterranean concrete pier and an attachment end for attachment to an adjacent wall, fence, barricade or partition panel. 5 The attachment end of the panel is preferably attached to an adjacent panel using bolts, screws or any other type of fixing means that may be chemset using an appropriate epoxy mortar. Once the panels have been arranged holes can be drilled and anchoring bolts can be inserted to hold the panels in place. BRIEF DESCRIPTION OF THE DRAWINGS 10 The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several implementations of the invention and, together with the description and claims, serve to explain the advantages and principles of the invention. In the drawings, Figure 1 is a perspective view of one embodiment of the retaining wall of the 15 present invention; Figure 2 is a rear perspective view of the retaining wall of figure 1 illustrating the internal reinforcement and expansion joint; Figure 3a is a perspective view of the mould used to form the retaining wall panel of figure 1; 20 Figure 3b is a front perspective view of the panel of figure 3a during installation; Figure 4 is a perspective view of the retaining wall of figure 1 installed on slopping ground; Figure 5 is a perspective view of an alternate embodiment of the retaining wall panels; and 25 Figure 6 is a perspective view of another alternate embodiment of the retaining wall panels.

9 DETAILED DESCRIPTION OF THE ILLUSTRATED AND EXEMPLIFIED EMBODIMENTS Similar reference characters indicate corresponding parts throughout the drawings. Dimensions of certain parts shown in the drawings may have been 5 modified and/or exaggerated for the purposes of clarity or illustration. Referring to the drawings for a more detailed description, a retaining wall 10 is illustrated, demonstrating by way of examples arrangements in which the principles of the present invention may be employed. Figure 1 illustrates a retaining wall 10 having wall panels 12a, 12b, 12c, 12d. Each wall panel 12(a-d) is connected at a 10 fixable end 14 to a support member 16 and has a free end 18 that engages with an engagement means 20 of an adjacent wall panel. For instance, wall panels 12a includes a fixable end 14 that is attached to support member 16 and a free end 18 for engagement with adjacent wall panel 12b. The fixable end 14 includes an engagement means 20 for engagement with a free end 18 of adjacent wall panel 15 12c. In its simplest form each wall panel of the interlocking retaining wall 10 has the same dimensions. In the present embodiment wall panels 12(a-d) are 1200mm in height and 2450mm in length. The wall panels includes a generally planar rectangular body 22 and a forwardly extending pillar 24 at the fixable end 14. The 20 rectangular body 22 is 100mm in thickness and the pillar 24 is 300mm wide and has a thickness of 200mm with an engagement means 20 in the form of a rear stepped lip that is 100mm deep and 100mm wide. The support member 16 is a generally subterranean reinforced concrete pier having a 350mm diameter and a depth of 1800mm. The hole for the piers 16 are 25 excavated prior to positioning of the wall panels 12(a-d). It should be appreciated that the subterranean concrete piers are post-pour piers, in that the fence panels are positioned with respect to previously excavated holes. The panels are located in position using temporary stays and the reinforcement for the piers is attached to the underside of the panel such that the 30 reinforcement extends down into the hole. The concrete is then poured into the hole and allowed to cure before the temporary stays are removed.

10 As further illustrated in figure 1 the wall panels 12(a-c) are attached to corresponding piers 16, and it should be appreciated that wall panel 12d is also attached to a corresponding concrete pier (not shown). Once installed the free ends 18 of panels 12(a-d) are urged against the 5 engagement means 20 by the weight of the soil and rock 26 retained behind the wall 10. In this way each of the wall panels 12(a-d) are fixed at one end 14 to a corresponding support 16, with the opposing end 18 being supported by the fixed end 14 of an adjacent wall panel and held in place by the weight of the soil and rock being retained by wall 10. This means that each wall panel provides support for the 10 free end of one adjacent wall panel and is itself supported at its free end by another adjacent wall panel. The engagement means 20 in the form of a rear stepped lip engages with the free end 18 of an adjacent wall panel. As illustrated in figure 2, the free end 18 of panel 12a engages with the rear stepped lip 20 of panel 12b. The lip 20 is positioned 15 on the oppose side of the pillar 24 to the planar rectangular body 22 of the wall panel 12b. In this way when adjacent wall panels 12a, 12b are in position the two planar rectangular bodies 22 are substantially coplanar. As further illustrated in figure 2, the adjacent panels 12a, 12b are separated by an expansion joint 28 that is preferably 5mm wide to compensate for any 20 expansion in the concrete material due to temperature change. As can be appreciated this expansion joint is hidden from view behind the pillar 24. Furthermore the overlap resulting from the registry of the free end 18 behind an adjacent pillar 24 ensures that the front of the planar body 22 bears against the front edge or shoulder of the lip 20 which prevent movement of the soil therethrough whilst 25 still providing an expansion joint. It may also mean that there is no requirement to use silicon filler within the expansion joint, although such material may still be used to inhibit movement of water therethrough and in such a case the silicon filler will not be exposed to UV radiation that can cause degradation. The wall panels 12 are prefabricated concrete panels that include steel mesh 30 reinforcement 30. The concrete used for the panels is preferably N32 grade and the steel reinforcement comprises grade 500 square or rectangular mesh, hot rolled deformed bar and hot rolled plain round bar.

11 The forwardly extending pillar 24 is of a size to accommodate a reinforcement means 32 and a depending coupling means 34 for connecting the fixable end 14 of the panel 12 to the support member 16. The coupling means 34 is used to connect the reinforcement means 32 of the wall panel 12 with reinforcement means 36 of the 5 post-pour concrete pier 16. The reinforcement means 36 of the concrete pier 16 includes two 12mm (n12) steel rods 38, 40 and two 20mm (n20) threaded reinforcement bars 42, 44, held together by steel ligatures 46. The concrete used for the pier 16 is preferably N25 grade complying with AS3600. Where the wall panel 12 is 1.2m in height the pier 16 10 is preferably founded between 1.8-2m into original undisturbed hard silty clay. The reinforcement means 32 of the concrete panels 12 includes two 12mm steel rods 48, 50 and two 20mm threaded reinforcement bars 52, 54, held together by steel ligatures 56. The coupling means 34 are two internally threaded couplings 58, 60 that are connected to threaded reinforcement bars 52, 54 prior to fabrication of 15 the wall panel 12. One end of the couplings 58, 60 is positioned generally flush with the bottom of the wall panel 12. This means that during transport of the wall panel there are no steel protrusions that may cause injury to a worker. The use of couplings 58, 60 means that the panel can be transported to the site and positioned such that the fixable ends 14 are above the excavated holes that 20 will accommodate the concrete pier 16. The reinforcement means 36 of the pier 16 can then be inserted into the hole and connected to the reinforcement means 32 of the concrete panel 12 by way of couplings 58, 60. This ensures that the reinforcement means 36 is suspended in the hole and ready for pouring of the concrete to form the pier 16. 25 The threaded bars 42, 44, 52, 54 may be 20mm REIDBAR@ steel rods attached using REIDBAR@ couplers. It should be appreciated that other types of couplers and reinforcement bars could be used including the product sold under the trade mark MonkeyBar@. Alternatively the pier reinforcement could be chemset into the underside of the wall panel using an appropriate epoxy mortar. 30 Although not illustrated it should be appreciated that one end of the retaining wall may be engaged by a steel C-section post to support the free end 18 of the first wall panel of the retaining wall that is not supported by an adjacent wall panel. In 12 another form the free end of a first wall panel may engage a registry means (not shown) attached to an existing wall or fixed structure. Figure 3a illustrating the fabrication of wall panel 12. Prior to casting wall panel 12 the individual reinforcement steel members, such as the mesh and steel 5 rods, are preworked into the mould. The reinforcement is supported within the mould 62 on plastic stools or mortar blocks (not shown) of equal strength and durability to the concrete mix, ensuring that there is a 40mm clear concrete cover over all the reinforcement excluding the couplings 58, 60. The wooden or steel mould 62 is placed horizontally, and casting is 10 performed, using a relatively fluid mix of concrete, by metering the fluid mix under manual control from the concrete feed hopper into the mould 62 in the direction of arrow 64 to form the rectangular body 22 and pillar 24 of wall panel 12. As further illustrated one end of the couplings 58, 60 are positioned generally flush with the bottom of the wall panel 12. The ends of the couplings 58, 60 are covered with a 15 sheet of material to ensure that the concrete mixture does not ingress into the open ends of the couplings 58, 60. The concrete is then compacted to reduce void content to a practical minimum. This is usually by vibration using high-frequency vibrators or mould mounted vibrating equipment, centrifugation, tamping, or a combination thereof. 20 As further illustrated in figure 3a, insert 66 is then imbedded into the freshly placed concrete in the direction of arrows 68. This insert forms the rear-stepped lip 20 in the back of the panel 12. As illustrated in figure 3b, pier support holes 70 are excavated prior to placement of the wall panels 12(a-d). The holes are dug at predetermined positions 25 to correspond with the calculated location of the pillars of said wall panels 12(a-d). It should however be appreciated that the exact location of the pier holes can be approximate because the concrete for the piers will not be poured until after the wall panels 12(a-d) are in place. This means that there can be a degree of leeway in the exact location of the holes 70. The pier support holes 70 would be around 2100mm 30 apart when the wall panels are 2450mm in length. The pier support holes 70 are preferably 350mm in diameter and between 1.8-2m deep.

13 The wall panels 12(a-d) are then positioned in an upright arrangement such that the exposed couplings are located above the prepared holes 70. The wall panels are supported with temporary stays 72 during casting of the concrete piers. Reinforcement means 36 for the piers 16 are then lowered into the holes and 5 attached to the exposed couplings 58, 60. It is envisaged that an anchor point (not shown) will be incorporated into the top edge of the panel 12 during fabrication. The anchor point may be engaged by a lifting clutch to assist in the lifting and transportation of the panel 12. The anchor point and lifting clutches may be those sold under the trade mark SWIFTLIFT® foot 10 anchor and clutch. Alternatively a female-threaded couplings may be incorporated into the top edge of the panel during fabrication of the panel 12. The temporary stays 72 can be connected to threaded couplings or anchor points during installation of the panel 12. A flowable concrete mixture is poured into the holes 70 in the direction of 15 arrow 74 and allowed to cure. The concrete is compacted by immersed mechanical vibrators. The temporary stays 72 can then be removed and soil or rocks backfilled in behind the retaining wall 10. The backfill 26 acts to hold the free ends 18 of each wall panel 12(a-d) against the engagement means 20 of an adjacent wall panel. As illustrated in figure 4 the retaining wall can be installed on a slopping 20 surface 76. Due to the configuration of the engagement means 20 that includes a laterally extending lip 20 that extend down the entire edge of end 14, the top of adjacent wall panels do not have to be at the same height. Accordingly the retaining wall can be stepped down a hill or slope as is generally known in the art. Installation of the retaining wall of the present invention on a sloping surface 76 would require 25 some excavation however it would be appreciated that the amount of excavation required would be much less than many of the existing retaining wall systems. The engagement means 20 may also be set at an angle to the geometric plane of the rectangular body 22 of the wall panel. In this way various shaped retaining walls can be constructed. In one example as illustrated in figure 5, the 30 retaining wall comprises wall panels 78, 80a, 80b. Each of the wall panels 78, 80a, 80b include a forwardly extending curved pillar 82. The pillar 82 of wall panel 78 includes an engagement means 84 having a side or shoulder that is set at an angle of 450 to the plane of the wall panel. This 14 means that when wall panel 80b is positioned against the engagement means 84 the two panels 78, 80a are positioned with an internal angle of 135'. Wall panels 80a, 80b include engagement means 20 that are used to position adjacent wall panels along the same plane as discussed above. 5 In a further example, as illustrated in figure 6, the retaining wall 10 comprises wall panels 86, 12a, 12b. Wall panels 12a, 12b cooperate in a fashion as discussed above. Wall panel 86 includes a planar rectangular body 88 and two forwardly extending pillars 90, 92 connectable to subterranean pier supports 94. Pillar 90 includes an engagement means in the form of rearwardly positioned slot 96 being of 10 a size to accommodate the free end 18 of wall panel 12a. The slot 96 extends down the entire length of the rear of the pillar 90 and is positioned perpendicular to the plane of the body 88. This means that the retaining wall 10 of the present example can accommodate 90' corners. It should be appreciated that other angles are possible and the angle can be 15 set as required upon casting the wall panel. For instance the insert 66 illustrated in figure 3a can be imbedded into the concrete at an angle to the vertical or other shaped inserts could be used. As further illustrated in figure 6 the pillar 92 of wall panel 86 is also connectable to pier support 94. This is useful at the beginning of a retaining wall and in effect fixes both ends of the wall panel 86. 20 In another embodiment the wall panel 12 could be used in constructing a fence, partition, wall or barricade. In such an embodiment end 14 is connected to a subterranean concrete pier in a manner as discussed above. The end 18 of the wall panel 12 is attached to an adjacent panel using anchoring bolts (not shown) that in one embodiment may be chemset using an appropriate epoxy mortar. Once the 25 panels have been arranged holes are drilled and anchoring bolts, screws or other fixing means are inserted to hold the panels in place. The skilled addressee will now appreciate the many advantages of the present invention. The present invention provides a modular retaining wall that can be installed without the difficulties of accurately aligning support posts. The pier 30 support holes of the present invention are excavated prior to positioning of the wall panels. The wall panels are then set in place and attached to pier support reinforcement. Finally the concrete for the post pour piers is poured into the holes thereby securing the retaining wall. Furthermore, the use of a hidden expansion gap and interlocking walls provides many benefits over the prior art.

15 Various features of the invention have been particularly shown and described in connection with the exemplified embodiments of the invention, however, it should be understood that these particular arrangements merely illustrate and that the invention is not limited thereto. Accordingly, the invention can include various 5 modifications, which fall within the spirit and scope of the invention. For the purpose of the specification the word "comprise" or "comprising" means "including but not limited to".

Claims (20)

1. A retaining wall including a plurality of wall panels each having a fixable end for attachment to a support member and an opposing free end for engagement with a first adjacent wall panel, said fixable end including an 5 engagement means for engagement with a free end of a second adjacent wall panel, wherein the free ends of the plurality of wall panels are urged against the engagement means of adjacent wall panels by the pressure of the material held behind said retaining wall.

2. The retaining wall in accordance with claim 1 wherein the wall panels are cast 10 concrete panels including an internal reinforcement means.

3. The retaining wall in accordance with claim 1 or 2 wherein reinforcement rods are positioned within the wall panels at the fixable end.

4. The retaining wall in accordance with claim 2 wherein the fixable end of said panel includes an attachment means for attachment to the support member, 15 said attachment means being connected to said reinforcement means.

5. The retaining wall in accordance with claim 4 wherein the attachment means is a depending coupling, said coupling being used to connect said reinforcement means of the wall panel to a reinforcement means of said support member. 20

6. The retaining wall in accordance with any one of the above claims wherein the support member is a substantially subterranean concrete pier support.

7. The retaining wall in accordance with any one of claims 1 to 6 wherein each wall panel includes a generally planar rectangular body and a forwardly extending pillar at said fixable end, the rectangular body having a front face, 25 generally parallel top and bottom edges, and perpendicular, generally parallel, first and second sides extending therein between, the first side being located at the fixable end of the panel and the second side being located at the free end of the panel.

8. The retaining wall in accordance with claim 7 wherein the engagement means 30 is a lip being stepped into the rear of the wall panel and extending down the length of the first side, the lip including a generally planar shoulder surface 17 perpendicular to a generally planar side surface thereby forming a recessed corner for engagement with the generally right angle edge of the free end of an adjacent wall panel.

9. The retaining wall in accordance with claim 8 wherein the shoulder surface of 5 said lip is 100mm wide and side surface of said lip is 100mm wide, the shoulder surface of said lip being parallel to a front face of the rectangular body, wherein when adjacent wall panels are installed the respective planar rectangular bodies are substantially coplanar.

10. The retaining wall in accordance with claim 8 wherein the shoulder surface of 10 said lip extends rearwardly or forwardly at an angle to said front face of the rectangular body wherein when adjacent wall panels are installed the respective planar rectangular bodies are at an angle relative to the vertical plane.

11. The retaining wall in accordance with any one of the above claims wherein 15 the free end of the panel located at the end of the retaining wall is supported by a retention means selected from a group containing, steel H or C-section posts, wall mounted channels or a registry means attached to an existing wall or fixed structure.

12. A method of constructing a retaining wall including a plurality of wall panels, 20 including the steps of: excavating a series of pier support holes at known distances; positioning a plurality of wall panels, each having a generally planar body, a fixable end and an opposing free end, wherein the fixable end of each wall panel is positioned over a corresponding excavated hole and the free end of 25 each wall panel positively registers with an engagement means of an adjacent wall panel; attaching the fixable end of each wall panel to a support member located within said excavated hole; and pouring a flowable concrete mixture into pier support holes to thereby form 30 substantially subterranean concrete piers.

13. The method of constructing a retaining wall in accordance with claim 12 wherein the fixable end includes a pillar that partially accommodates depending couplings wherein the wall panels are positioned in an upright 18 position such that an exposed end of said depending couplings are located above the excavated pier support holes.

14. The method of constructing a retaining wall in accordance with claim 13 wherein the wall panels are supported with temporary stays, and main 5 reinforcement bars are lowered into the excavated pier support holes and attached to the exposed end of the depending couplings.

15. The method of constructing a retaining wall in accordance with any one of claims 12 to 14 wherein the subterranean concrete piers are post-pour piers, in that the panels are positioned with respect to previously excavated holes. 10

16. The method of constructing a retaining wall in accordance with claim 12 wherein the pier reinforcement is chemset into the underside of the wall panel using an appropriate epoxy mortar.

17. A wall, fence, barricade or partition including a plurality of wall panels each having a fixable end for attachment to a support member and an opposing 15 free end for engagement with a first adjacent wall panel, said fixable end including an engagement means for engagement with a free end of a second adjacent wall panel, wherein the free end of the second adjacent wall panel being connected to the engagement means.

18. The wall, fence, barricade or partition in accordance with claim 17 wherein the 20 second adjacent wall panel may be attached to the engagement means using bolts that may be chemset by way of an appropriate epoxy mortar.

19. The wall, fence, barricade or partition in accordance with claim 17 or 18 wherein the support member being selected from a group containing fence posts, subterranean concrete piers and pillars. 25

20. An apparatus as hereinbefore described with reference to the figures.