TECHNICAL FIELD

[0001] The present invention is in the field of shoring panels. More specifically, it relates to prefabricated shoring panels with reinforced anchor pads and embedded reinforcing meshes.

BACKGROUND

[0002] Prior to constructing high-rise buildings, for example, the ground is excavated to provide room for foundations and floors that are below ground level. During and after excavation, the exposed walls are at risk of collapse and are therefore shored up. One method of shoring involves drilling anchor holes in the walls, pouring or spraying concrete in separate patches on the exposed wall around the anchor points, allowing the concrete to set into a panel, and then tensioning anchors to hold the panels to the wall. The process is then repeated for the intervening areas of the wall that remain exposed, so that the entire excavated face is covered and retained. As the concrete is poured on site, enough time must be allowed for the concrete to set and sufficiently harden. During this time, for example overnight, there is some risk that the ground will collapse.

[0003] Japanese patent application no. H07197469A to Fukuda et al. discloses a retaining wall made using piles, an earth retaining face, anchors and walings.

[0004] Korean patent application no. 20120030513A to Kim discloses a concrete retaining wall structure using an anchor and a precast panel. Each precast panel has a front panel, a rear panel, a drain groove, a mortar filling groove, and an anchor hole.

[0005] This background is not intended, nor should be construed, to constitute prior art against the present invention.

SUMMARY

[0006] The prefabricated shoring panel has a reinforced anchor pad either on its outer side in the form of a wedge, or recessed in a countersunk hole in the panel. The front or outward face of the wedge that supports the load of the anchor is angled so that it is approximately perpendicular to the longitudinal direction of the anchor. A wire mesh is embedded in the prefabricated shoring panel to provide reinforcement. The wire mesh may project out of the sides of the panel to provide reinforcement for additional concrete that is used to fill the gaps between neighboring panels after they have been installed. The rear or inner face of the panel may have dimples or other structures to seat and stabilize the prefabricated shoring panel to the exposed wall.

[0007] The panels are suitable for retaining a variety of different ground materials, varying from sand to hard rock. Multiple levels of panels may be installed on deep excavations, such as required for buildings with multiple underground floors.

[0008] An advantage of construction projects that make use of the prefabricated shoring panel is the speeding up of the shoring task. In some cases, the time saving is potentially 35% to 45%. Another advantage is that the prefabricated shoring panels can be used such that the excavated region is not left unsupported overnight. Also, quality control may be implemented more effectively, and sloughing may be prevented or reduced in poor ground conditions. Furthermore, the prefabricated shoring panels can be made waterproof, which prevents washouts. Embodiments may provide one or more of these advantages depending on their configuration and use.

[0009] Disclosed herein is a panel for shoring an excavated wall comprising: a base that has a front face and a rear face connected by edges; an anchor pad defined in the panel; reinforcement embedded in the panel; and wire mesh embedded in the base; wherein the anchor pad defines an opening of an anchor hole that passes through the panel. In some embodiments, the anchor pad projects out from the front face of the base, and in other embodiments the anchor pad is countersunk in the base.

[0010] Also disclosed is a method for shoring an excavated wall comprising: placing a shoring panel over an anchor that is fixed in a hole drilled in the excavated wall, wherein the shoring panel has a base that has a front face and a rear face connected by edges, an anchor pad defined in the panel, reinforcement embedded in the panel, and wire mesh embedded in the base, wherein the anchor pad defines an opening of an anchor hole that passes through the panel, the anchor hole accommodating the anchor; placing an anchor plate over the anchor onto the anchor pad; and tensioning the anchor against the anchor plate so that the panel is held against the excavated wall.

BRIEF DESCRIPTION OF DRAWINGS

[0011] The following drawings illustrate embodiments of the invention, which should not be construed as restricting the scope of the invention in any way.

[0012] FIG. 1 is a three-dimensional view of a prefabricated shoring panel, according to an embodiment of the invention.

[0013] FIG. 2 shows a front view of the prefabricated shoring panel, according to an embodiment of the invention.

[0014] FIG. 3 shows a side view of the prefabricated shoring panel, according to an embodiment of the invention.

[0015] FIG. 4 is a rear view showing the inner face of the base of the prefabricated shoring panel, according to an embodiment of the invention.

[0016] FIG. 5 is a partial cross-sectional view showing the profile of dimples in the prefabricated shoring panel, according to an embodiment of the invention.

[0017] FIG. 6 is a front view of a prefabricated shoring panel with its reinforcement system, according to an embodiment of the invention.

[0018] FIG. 7 is a side view of the prefabricated shoring panel of FIG. 6, showing the dimples and the reinforcement system, according to an embodiment of the invention.

[0019] FIG. 8 is a plan view of the rebars and welded wire mesh in the prefabricated shoring panel, according to an embodiment of the invention.

[0020] FIG. 9 is a side view of the rebars and mesh of FIG. 8, according to an embodiment of the invention.

[0021] FIG. 10 is an elevational view of the prefabricated shoring panel with its reinforcement system, according to an embodiment of the invention. [0022] FIG. 11 is a partial cross-sectional view from the side of the prefabricated shoring panel, according to an embodiment of the invention.

[0023] FIG. 12 shows a prefabricated shoring panel seen from the front, according to another embodiment of the present invention.

[0024] FIG. 13 shows a prefabricated shoring panel seen from the side, according to another embodiment of the present invention.

[0025] FIG. 14 shows a flowchart describing the steps to install the prefabricated shoring panel, according to an embodiment of the present invention.

[0026] FIG. 15 shows a cross-sectional view of a prior art form of shoring using shotcrete.

[0027] FIG. 16 shows a side view of an alternate prefabricated shoring panel, according to an embodiment of the present invention.

[0028] FIG. 17 shows a side view of another prefabricated shoring panel, according to an embodiment of the present invention.

DETAILED DESCRIPTION

A. Glossary

[0029] Dimples refer to recesses or other surface features that increase a surface's unevenness. Dimples, or the equivalent, are incorporated in a surface to enhance the friction between the surface and an element in contact with the surface. Other features such as pads (reverse dimples), ridges, projections, and spears may be used to increase a surface's unevenness.

[0030] Grout is mortar that is usually used to fill cavities or joints in order to form a solid bond between two elements of a structure.

[0031] Lifting eyes are usually used in the construction industry to lift various structural elements on site. They can be made of stainless steel or high tensile steel, and can have different shapes such as oval or circular, for example. The term "lifting eyes" encompasses other lifting features such as eye nuts.

[0032] Rebars are steel bars or meshes of steel wires assembled together and are used in the construction industry to reinforce concrete structures. The rebars increase the tensile strength of the concrete.

[0033] Reinforcement is a term used to refer to reinforcement such as welded wire mesh or rebar.

[0034] Shoring is the setting up of a temporary or permanent structure to prevent the collapse of rock or earth during construction.

[0035] Shotcrete is a form of concrete that can be sprayed into place via a hose connected to a pump. This type of concrete can be either a dry or wet mix.

[0036] Welded wire mesh or WWM is made of interlocking metal wire such as steel, stainless steel or other materials. WWM can be used for the reinforcement of concrete.

B. Exemplary embodiments

[0037] Referring to FIG. 1 , the prefabricated shoring panel 10 (hereinafter "panel" for brevity) has a base 12 with a planar, front or outward face 14 and a rear or inner face 18 (FIG. 3). Edges 16 around the base 12 connect the front face 14 to the rear face 18. An anchor pad 22 projects from the front face 14 of the base 12 of the panel 10. In some embodiments, the front face 14 of the panel is a square with a side between 0.5 and 3 m. The typical panel sizes are 1.2 m by 1.2 m, or 1.5 m by 1.2 m, not including the WWM 24 (welded wire mesh) or other rebar extensions. In some embodiments, the panels 10 are custom ordered to the client’s dimensions.

[0038] An anchor hole 26 is defined in the anchor pad 22, the anchor hole also passing through the base 12 of the panel 10 to exit the rear face 18 of the panel. The anchor hole 26 is for the anchor to pass through the panel 10 for retaining and tensioning the panel to the excavated wall. The front face 30 (i.e. exposed face) of the anchor pad 20 is angled relative to the plane of the front face 14 of the base 12 of the panel 10. Typically, anchors that retain shoring panels are directed downwards from the horizontal at an angle, as they extend from the excavated wall into the ground behind the excavated wall.

[0039] A WWM 24 is partially embedded in the base 12 of the panel 10. The WWM 24 is made of welded wires in a square grid. The wires are spaced apart from each other by 0.1 m intervals, for example, and extend 0.25 m outward from the base 12 of the panel 10. The welded wire in the WWM 24 is, for example, 8/8 gauge galvanized steel. In some embodiments, the WWM 24 has different dimensions. In some embodiments, the welded wires from the WWM 24 are spaced at 0.025; 0.05 or 0.075 m intervals. In some embodiments, the spacing between welded wires in the WWM 24 is greater than 0.1 m. In some embodiments, the WWM 24 does not extend out from the base 12 of the panel 10.

[0040] A lip 28 is located on the outer edges of the front face 14 of the base 12 of panel 10 for the attachment of a waterproof membrane. In some embodiments, the lips 28 have holes to facilitate the attachment of the membranes. In some embodiments, lips 28 are used for attaching other types of reinforcement structures or devices, or additional joining elements to connect to adjacent panels. The lip 28 overhangs the top edge of the front face 14 of the base 12 of the panel 10. The lip 28 is cast in place in the panel 10 or affixed to it after casting. Flanges 32 project from the sides of the base 12 of the panel 10. A flange also extends from the lower edge of the base 12 of the panel 10. The flanges 32 are cast in place in the panel 10 or affixed to it after casting.

[0041] FIGS. 2 and 3 show a front and a side view of the panel 10 respectively. The anchor pad 22 is located in the central region of the front face 14 of the base 12 of the panel 10. The anchor hole 26 is located in the central region of the front face 30 of the anchor pad 22. The anchor hole 26 is perpendicular to the front face 30 of the anchor pad 22. Flanges 32 are located at the left and right sides of the base 12 of the panel 10. Flange 34 extends from the bottom edge of the base 12.

[0042] Four post-grout holes 42 are located in the front face 14 of the base 12 in the vicinity of each corner of the anchor pad 22. These post-grout holes 42 allow excess filling material, e.g. grout or concrete, that is placed behind the panel 10 to escape as the panel is tensioned to the excavated wall.

[0043] The anchor pad 22 is a 6-faced irregular polyhedron with a rectangular back face or inner face 46 that interfaces with the base 12 of the panel 10. The anchor pad 22 is an integral protrusion or extension of the base 12 of the panel 10, as they are cast as one piece. The anchor pad 22 has a front face 30 inclined in such a way that its lower edge 50 protrudes from the front face 14 of the panel more than its upper edge 54. The front face 30 of the anchor pad 22 is inclined with an angle a (e.g. 15°) to the front face 14 of the base 12 of the panel 10. Its lower edge 50 is shorter than its upper edge 54. The lower face 56 of the anchor pad forms an angle b (e.g. 45°) with the front face 14 of the base 12 of the panel 10. In some embodiments, the geometry and the dimensions of the anchor pad 22 are different.

[0044] FIG. 4 shows the rear face 100 of the base 12 of panel 10, showing detail of the dimples 104 between ridges 106. In this figure, the anchor pad is not visible. The hole 26 for the anchor is shown.

[0045] FIG. 5 shows the profile of the dimples 104 more clearly. The dimples 104 have a central flat face surrounded by ridges 106. The dimples 104 have a square shape that is, for example, of side 120 mm. In other embodiments, the dimples 104 may have other shapes, such as rectangular, hexagonal, triangular, irregular or other tessellating shapes. The ridges 106 between the dimples 104 may have walls at angles other than 45°. The ridges between adjacent dimples 104 may have a triangular cross-section or may be flat-topped walls with sloping sides.

[0046] When the rear face 100 is in contact with the excavated face, the ridges 106 help to increase the friction between the rear face 100 and the ground material in the excavated face. This reduces the risk of potentially loose material moving around the behind the rear face 100 over time.

[0047] The main requirement for the rear face 100 of the panel 10 is that there is some surface structure on it, to help seat the panel on the excavated wall. In some embodiments, the surface profiles of the dimples 104 have different configurations depending on the class of ground material, which may be soft, medium or hard ground. Panels for retaining soft ground have a deeper dimple profile, and panels for retaining hard ground have a shallower profile. An intermediate depth of dimple may be used for medium ground hardness. For example, for medium hardness ground, the depth of the dimples 104 may have a medium depth (in some embodiments, 19 mm). For softer ground, the depth of the dimples 104 is deeper (in some embodiments, 26 mm). For harder ground, the depth of the dimples 104 is shallower (in some embodiments, 13 mm). In some embodiments, the surface profiles of the seating dimples 104 have other configurations in order to adapt to a wider variety of ground material.

[0048] FIG. 6 shows the front of a prefabricated shoring panel 200 with wire ropes 204 extending from within the panel. The wire ropes 204 are, far example, 10 mm diameter galvanized wire ropes terminated with wire rope clips 208 at each end. The rope clips 208 are embedded inside the panel 200. In some embodiments, another way to fasten the wire ropes 204 to the panel 200 is used. These wire ropes 204 are used for lifting the panel 200. In other embodiments, the wire ropes are not present.

[0049] Lifting eyes or manipulators 212 are also included in the panel 200. A lifting eye 212 is a recess 214 in the surface of the panel 200, across which a metal bar 215 is spanned, 10 mm in diameter, with its ends embedded in the panel 200. In some embodiments, the lifting 212 eyes are optional. The lifting eyes 212 are used for a controlled positioning of the panel 200 against the face of the excavated wall as the anchor is tensioned against the anchor pad 220. The lifting eyes 212 are also used for jiggling or vibrating the panel 200 against the excavated wall prior to final tensioning of the anchor.

[0050] Rebars 228, 230 are positioned in the panel 200. These rebars are arranged in such a way to provide reinforcement for the panel 200, and they may be referred to simply as "reinforcement". In some embodiments, the location of the rebars 228, 230 in the panel 200 is different, depending on the overall configuration of the panel. In this embodiment, four rebars 228 are used perpendicular to four rebars 230. Besides this reinforcement (i.e. rebars 228, 230), the WWM 236 may also be considered to be reinforcement. As such, there are two different kinds of reinforcement in the panel 200. [0051] Post-grout (or cast) tubes 232, 234, both 13 mm in diameter and inclined 15° are cast in the panel 200. A first PVC (polyvinyl chloride) post-grout tube 232 is located above the anchor hole 216. A second PVC post-grout tube 234 is located below the anchor hole 216. The PVC post-grout tubes 232 and 234 are inclined with an angle of 15° to the front face 202 of the base of the panel 200. In some embodiments, the PVC post-grout tubes 232, 234 are made of a different material than PVC. For fully grouted anchors, the free anchor length, which is left after the initial anchoring bond is formed, is surrounded by grout injected through the post-grout tubes 232, 234 after the anchor is tensioned.

[0052] Also present in the panel 200 are post-grouting holes, post-grouting ports or weep holes 224. These allow excess filling material that is placed behind the panel 200 to escape as the panel is tensioned to the excavated wall. Four post-grouting holes 224 are located on the front face of the panel 200 in the upper section of the front face 202. The post-grouting holes 224 are aligned horizontally. In some embodiments, the number of post-grouting holes 224 is different. In some embodiments, the dimension, arrangement or configuration of the post-grouting holes 224 is different. Panels may be made as standard with, for example, 4 or 6 post grouting holes 224 depending on the panel 200 width. In some embodiments, additional post-grouting holes are drilled through the panel 200 after the placement of the panel on the excavated wall. WWM 236 is shown projecting from the edges of the base of the panel 200.

[0053] FIG. 7 is a side view showing the prefabricated shoring panel 200 with dimples 304 as hidden detail.

[0054] The wire rope 204 is set inside the panel 200 via a wire clip 208. Most of the wire rope 204 embedded inside the panel 200 is located closer to the rear face 316 than the front face 202 of the body of the panel. The part of the wire rope 204 located in the top region of the panel is embedded in the panel in such a way that it is brought closer to the front face 202. The wire rope 204 emerges from the top edge of the panel 200 in such a way that it is directed away from the WWM 236. This way when the wire ropes 204 are used to position or carry the panel 200, the balance of the panel is maintained to keep the panel in a vertical orientation. [0055] The rebars 228, 230 and the WWM 236 are cast inside the panel 200 to be approximately midway between the rear face 316 and the front face 202 of the panel.

[0056] Post-grout tubes 232 and 234 share the same inclination (15°) as the anchor hole 216. Post-grout tubes 232 and 234 pass through both the anchor pad 220 and the base 320 of the panel 200.

[0057] In some embodiments, the structure on the inner face 316 of the panel may be different to the dimples 304 as shown here. For example, the structure may be an array of pads (reverse dimples), ridges, projections, spears, etc, or may be described as a waffle structure. Spears may be ridged or have grooves. Spears may be made separately from the panel and attached to the back of it, e.g. using threaded rebar.

[0058] Referring to FIGS. 8 and 9, another arrangement of the WWM 330 and the rebars 334, 338 for a panel is shown. Rebars 334, 338 may also be referred to simply as "reinforcement". The rebars 334 and 338 are positioned in the panel in such a way as to provide reinforcement to the anchor pad and base, respectively, of the panel.

[0059] Rebars 338 are positioned so that they lie within the planar portion, or base, of the panel. Each rebar 338 is made of a long straight portion and a shorter section connected by a short elbow. The rebars 338 are arranged in an X-shape geometry with a total of 8 rebars. Depending on the embodiment, rebars 338 may or may not be connected to each other.

[0060] Rebars 334 are positioned so that they lie within the anchor pad. The rebars 334 that reinforce the anchor pad extend into the base of the panel. There are 4 rebars 334 that reinforce the anchor pad. They are in a cross-shaped arrangement, in two pairs of equally spaced bent bars. They follow the overall shape of the anchor pad. Depending on the embodiment, rebars 334 may or may not be connected to each other. In some embodiments, the rebars 334 are bonded or attached to the rebars 338 located in the base of the panel. In some embodiments, the rebars 334 from the anchor pad are extensions of the rebars 338 in the base of the panel. Rebars 334, 338 may be considered to be reinforcement that is separate from the reinforcement provided by the WWM 330. [0061] FIG. 10 is a sectional view of a panel as seen from its bottom edge, showing locations of the lifting eyes 404 on the base 400 of the panel. The lifting eyes 404 have a recess 405 in the concrete and a bent bar 406. The anchor pad 408 projects from the front face 410 of the base 400 of the panel. The WWM 424 is positioned below the set of rebars 412, 420. Block out dowels 416 are cast in the base 400 of the panel. For example, the block out dowels 416 are made of PVC (polyvinyl chloride) or other tube or rod. They may be removed after the panel has been cast to leave holes that can be inserted with rebar, which is then fixed in place with epoxy.

The rebar that is placed in the holes made by the block-out dowels 416 extends beyond the edges of the base 400 of the panel, and can be used for reinforcing concrete that is applied to the excavated face between the panels. The post-grout holes 430 are present above and below the anchor hole 432.

[0062] FIG. 11 is a side view of another anchor pad 500 projecting from the base 504 of a panel. An anchor plate 508, with anchor hole 509 and post-grout holes 510, is shown in contact with the front face 511 of the anchor pad 500. In use, an anchor would pass through the anchor hole 509 in the anchor plate 508 and anchor hole 512 in the panel to tension the panel to the excavated face. An anchor guide tube that passes through both the anchor pad and the base may be present in the anchor hole 512. Post-grout holes 510 in the anchor plate align with post-grout holes 516 in the panel. The wire rope 524 is positioned behind the rebars 528, 530, which are positioned behind the WWM 532.

[0063] FIGS. 12 and 13 show the front and side respectively of a panel 600 with anchor pad 604. Cast-in lifting anchors 608 are present in the base of the panel 600 around the anchor plate 604. Post-grout holes 612 are shown in the upper portion of the panel. The tubes 614 that are used to cast the post-grout holes 612 are still in place, and can be removed before the panel is used.

C. Exemplary method

[0064] The specific design of the prefabricated shoring panel for a given excavation should be undertaken by a qualified design engineer. For example, the size, thickness, amount of reinforcement and strength of concrete selected should be appropriate for the particular excavation that needs shoring.

[0065] Referring to FIG. 14, upon receiving the design, the panels are pre-cast in step 800, numbered by row and panel (or anchor) number, or by row and column. The panel anchor holes are cast to site specific anchor size, type and inclination. The panels may come with many options. For example, options may include precast sockets for epoxy installed rebar dowels.

[0066] In step 804, the ground is excavated where the first panels are to be installed. Depending on the type of ground, the excavation may be partial to leave temporary berms or buttresses which are removed after the first panels are installed.

[0067] Anchor holes are then drilled in step 808, as per a typical anchor/shotcrete installation. Anchors holes are pre-drilled, prior to installation of the panels. The anchor holes are located so that when the panels are positioned, there is an overlap (e.g. 20 cm) of the wire mesh that projects from the sides of neighboring panels.

[0068] The anchors are then placed into the anchor holes in step 812.

[0069] In step 816, the anchors are fixed by applying grout to the anchor holes with the anchors in place. When the anchor grout is cured and the pre-installed anchors are ready to accept the panels, excavation of the panel areas is completed, if necessary, and trimmed carefully around the anchors. Some hand trimming may be required. Batter boards and string lines are a suggested control system to ensure against over-excavation.

[0070] The panels are then lifted up and placed at the desired position and elevation over the anchors in step 820. To place the panel, it may be picked up by the excavator using a quick connect “manipulator”, for example. The panel is connected to manipulator at four connecting points (lifting eyes), ensuring safety with the four connection points. The panel is then placed over the anchor and seated against the soil. With the vibratory option, seating of the panel against the soil is helped. At this point the panel orientation is checked and corrected if required. [0071] At this point, the anchors are left projecting through the anchor pads of the panels. There is an overlap (e.g. 20 cm) of the wire mesh that projects from the sides of neighboring panels.

[0072] Any required drainage matting is then placed, in step 822. In some cases, waterproof backing material is installed between the rear face of the panels and the exposed face of the excavated wall. Consideration is therefore needed as to the profile of the dimples on the panels so that the backing material is not punctured as the panels are positioned on the excavated wall and the anchors tensioned.

[0073] Should over-excavation have occurred, any voids may be backfilled with free-draining pea gravel in step 824. In some cases, concrete is pumped behind the panel to help fill any gaps between the panel and the excavated wall. Other material, e.g. some kinds of waste material, may also be placed behind the panels.

[0074] After the backfilling step 824, the panel is tensioned in step 828. A steel backing plate (anchor plate 508) is then placed over the projecting end of the anchor followed by an anchor nut. Using a hydraulic wrench, the nut is tightened onto the anchor to tension the panel to the excavated wall with the specified load. The outer WWM extending from the panel is then flattened, if necessary, over the surface of the excavated face. As soon as the panels are in place and tensioned, the risk of collapse of the excavated wall is greatly minimized. The time to install the panels, since they are prefabricated, is significantly shorter than if the excavated wall were to be retained by concrete entirely poured on-site.

[0075] Additional mesh may be then added to fill any gaps between the panels. A minimum of a 2 square (e.g. 20 cm) overlap is advisable when adding connecting mesh. Pins are used to secure the extra mesh, if required.

[0076] When the panels have been tensioned and any extra mesh added, shotcrete is applied, in step 832, over the exposed mesh, some of which is overlapping, and around the panels to tie the panels to each other. Depending on ground conditions and design, shotcrete may not be required in some installations.

D. Alternate embodiment [0077] FIG. 15 shows a prior art shoring arrangement. In this, a wall is formed by shotcreting onto an excavated wall around a pre-installed anchor. An anchor pad is formed in the shotcrete, inclined to the face of the excavated wall and the body of the shotcrete panel, and under-flush with the outer face of the shotcrete. This countersunk anchor pad is formed prior to the shotcrete curing.

[0078] A blind-formed wall 900 with WWM reinforcement 904 is formed around anchor 908 with shotcrete. The WWM is, for example 8/8 gauge, with a 10 cm grid, and the wall 900 is about 10 cm thick. In about a 30 cm diameter zone around the anchor region, an area 912 of the wall is thickened to about 15 cm. Additional WWM 916 is used in the thickened area 912 of the wall. In some cases, additional shotcrete layers, or reinforced shotcrete layers, are applied depending on the type of soil or ground material of the excavated wall.

[0079] The anchor pad 920 is a flat surface formed in a recess 922 in the shotcrete panel. An anchor plate 924 is placed over the protruding end of the anchor. The back face of the anchor plate 924 is flush with the anchor pad 920.

[0080] The anchor is pre-installed in drilled hole 925. The protruding end 930 of the anchor 908 has a Dywidag™ thread. A nut 934 is screwed onto the end of the Dywidag™ thread against the anchor plate 924, in order to tension the anchor 908. A portion A of the anchor 908 is not bonded to the surrounding ground and is therefore the portion of the anchor that can extend freely to stress the anchor. The portion B of the anchor 908 is bonded to the surrounding ground 926 and is the part of the anchor that is fixed. For fully grouted anchors, it is possible to post-grout the free anchor length A after locking off the anchor nut 934 and obtaining the necessary approval. To do this, suitable post-grout holes are needed in the anchor plate 924, the anchor pad 920 and the thickened area 912 of the wall.

[0081] As the anchor ends may need to lie flush or underflush with the completed shoring, as in FIG. 15, this can also be achieved with the present invention. To do this, prefabricated shoring panels may be made with a countersunk anchor pad rather than an anchor pad that projects from the surface of the panel. [0082] Referring to FIG. 16, a prefabricated shoring panel 950 is shown in which there is a recess 952 or countersink in the front face of the panel. The anchor pad 954 is a surface lying within the body of the planar part of the panel 950, at an angle to the front surface of the panel. The anchor hole 956 is perpendicular to the surface of the anchor pad 954.

[0083] The panel 950 is reinforced with rebars 960, 962 and 964, for example. Rebar 962 extends below the anchor pad 954 and may be considered to be reinforcement of the anchor pad. The rebars may be located in other positions in other embodiments. The WWM 966 extends out of the panel as in other embodiments.

[0084] The rear surface 968 of the panel 950 may include surface features, such as dimples or projections.

[0085] Referring to FIG. 17, another prefabricated shoring panel 970 is shown in which there is a thickened region 971 at the rear of the panel and a recess 972 or countersink in the front face of the panel. The anchor pad 974 is a surface lying within the panel 970, at an angle to the front surface of the panel. The anchor hole 976 is perpendicular to the surface of the anchor pad 974.

[0086] The panel 970 is reinforced with rebars 980, 982 and 984, for example. Rebar 984 extends below the anchor pad 974 and may be considered to be reinforcement of the anchor pad. The rebars may be located in other positions in other embodiments. The WWM 986 extends out of the panel as in other embodiments. Part of the WWM 986 needs to be cut out to leave the anchor pad 974 unobstructed.

[0087] The rear surface 988 (rear face) of the panel 970 may include surface features, such as dimples or projections. The rear surface of the thickened region of the panel 971 may also include surface features, such as dimples or projections. The rear face of the thickened region 971 and the rear face 988 together form the rear face of the panel 970, or of the base of the panel.

E. Variations

[0088] The panels have many options. Lightweight concrete can be used for casting the panels. The panel may be made of 25 MPa concrete as standard, or lower or higher strengths may be used. Additional vertical or horizontal rebar walers can be added. Most waste grout ports can be added to the panels. Different size soil-facing projection rods can be used depending on soil conditions. Leveling shims may be used to adjust the position, angle and orientation of the panels. Many different sizes of mesh may be incorporated in the panels.

[0089] The panel can be made to accept any size of anchor, including those with DCP (double corrosion protection). Panels may be made to accept post grout tubes if required. In some embodiments, the panel has multiple anchor pads on its front face. For example, anchor pads are placed in each quadrant of the base of the panel. The panels may be made without the flanges and lip.

[0090] In some embodiments, the anchor pad 22 is made as a separate component to the base 12 of the panel 10, and is tethered or otherwise fastened to the front face 14 of the base 12.

[0091] In some embodiments, two pairs of wire ropes are embedded inside the panel with one set positioned closer to the front face while the other set is positioned closer to the inner face. This may be used to improve the balance of the panel when placing it.

[0092] It should also be noted that these panels can be used in conjunction with typical conventional shoring systems.

[0093] In some embodiments, the panel is made without the dimples or any other surface feature on the rear face. The angle between the outer face of the anchor pad and the outer face 12 of the base of the panel 10 may be 15° in some embodiments and other angles in other embodiments, depending on the angle at which the anchor is to be inserted in the ground and the angle at which the panel is to be installed.

[0094] Sizes of rebars, WWM, lifting bar, lifting eyes and wire ropes may be different in other embodiments than shown herein. Dimensions, proportions, angles, shapes, sizes, positions, materials, configurations and quantity of all features of the panel may be different in other embodiments. Some of the features described herein may be omitted in some embodiments of the panel. Additional features may be incorporated into the panel.

[0095] Throughout the description, specific details have been set forth in order to provide a more thorough understanding of the invention. However, the invention may be practised without these particulars. In other instances, well known elements have not been shown or described in detail and repetitions of steps and features have been omitted to avoid unnecessarily obscuring the invention. Accordingly, the specification is to be regarded in an illustrative, rather than a restrictive, sense. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the claims.