EP0864017B1

EP0864017B1 - Earth structures

Info

Publication number: EP0864017B1
Application number: EP96940027A
Authority: EP
Inventors: Henri Charles Vidal; Jean-Marc Jailloux
Original assignee: Societe Civile des Brevets Henri Vidal
Current assignee: Societe Civile des Brevets Henri Vidal
Priority date: 1995-12-01
Filing date: 1996-11-29
Publication date: 2003-07-30
Anticipated expiration: 2016-11-29
Also published as: BR9611681A; JP3840263B2; JP2000501468A; DE69629310D1; AU7703396A; AU722475B2; IL124644A0; CN1203647A; EP0864017A1; WO1997020996A1; MX9804359A; CA2239016A1; KR19990071824A; AR004823A1; TR199800982T2; TW330958B

Description

This invention relates to facing elements for earth structures, such as stabilised earth structures, and to earth structures having a facing made up of such facing elements. It also relates to earth stabilising members for earth structures.

It is frequently necessary to provide earth structures, such as embankments, in civil engineering projects. Such structures comprise a mass of earth which must be securely retained, typically with at least one steep facing. One method of mechanically stabilising the earth is to use the so-called tie and anchor technique in which strong facing elements hold back a mass of earth, the facing elements being held in place by means of ties or the like which pass through the mass of earth to dead-man anchors. An alternative technique is to stabilise the earth by means of a plurality of frictional stabilising elements extending rearwardly from a facing of the structure into the earth mass. In these structures, the earth is stabilised throughout the mass by frictional engagement with the stabilising elements, which may for example be in the form of strips, sheets or grids. Commonly, the facing of the structure consists of facing elements in the form of concrete panels which are connected to the forward ends of the frictional stabilising elements. A variety of arrangements of such a system are known from GB-A-1 324 686.

It is known from GB-A-1 324 686, to provide a facing formed from a number of like concrete panels connected to stabilising strips. In some of the systems described, lugs are cast into the panels to form connection points for stabilising strips. Although these systems have been highly successful, they do suffer from certain drawbacks. In particular, the concrete panels have to be comparatively thick in order to have sufficient strength to provide a secure connection to the stabilising strip and to allow forces to be transmitted between the panels and the strip. The thickness of the panels results in comparatively high material and transport costs, and also increases the difficulty of handling the panels on site.

It was also proposed in GB-A-1 324 686 to connect the earth stabilising strips to pins located in vertical holes in the edges of the concrete facing panels. However, this system was never put in to commercial production, possibly because it was considered that even thicker panels would have been required to cope with the concentration of loads caused by providing the panel to strip connections at the edges of the panels.

It is known from JP-A-5565635 to provide a facing element for use in a stabilised earth structure, the facing element comprising:

a central portion,

a plurality of reinforcing portions extending substantially across the facing element and converging at corner regions of the facing element so as to define a flange extending substantially about the periphery of the facing element outwardly of the central portion. The structure includes connection means for connecting vertically adjacent facing elements and for connection to earth stabilising members.

The present invention is characterised by a dual function connection point at a said corner region for connection to a vertically adjacent facing element and to an earth stabilising member, the connection point including either a connecting pin or a hole for receiving a connecting pin, such that, when the facing element is assembled in said stabilised earth structure with said vertically adjacent facing element, the facing element is connected at said corner region to said vertically adjacent facing element by said connecting pin.

The invention also extends to an earth structure having a facing comprising such facing elements, wherein at least one earth stabilising member is connected to the facing elements.

As the reinforcing portions extend substantially across the element, they significantly strengthen the element and are able to transfer forces effectively between the element and an earth stabilising member and an adjacent element. As a result, the remainder of the element can be made thinner, and therefore lighter, than is the case with conventional elements. Consequently, the overall weight of the element may be significantly reduced, leading to lower material, transport, handling and erection costs.

Since the connection point is used for connecting the element to an earth stabilising member, the design of the facing element can be simplified compared to conventional facing elements in which the connection point is provided inset from the edge of the element.

The reinforcing portions preferably extend upwardly/downwardly, i.e. vertically when the facing element forms part of a vertical facing, or at a rearwardly tilted angle to the vertical when the facing element is itself rearwardly tilted in a battered facing.

In an embodiment a reinforcing portion is provided at each edge of the element. Thus, a plurality of reinforcing portions together extend about substantially the entire periphery of the facing element.

The reinforcing portions can be formed in a number of ways, for example, they can be formed integrally with the remainder of the element. Thus, if the element is formed of cast concrete, as is conventional, ribs or other reinforcing profiles could be cast as part of the element. The connection point for the stabilising member and adjacent facing element can then be formed at one end of the reinforcing profile, eg. by casting a connecting pin or lug to project from the profile or providing a hole in the profile into which a connecting pin or lug (which may be a separate pin or lug or may be formed on a stabilising member or adjacent element) can be inserted. The plural reinforcing portions extending about the periphery of the facing element are then provided by a thickened peripherally extending flange which surrounds a thinner central portion. The resultant facing element then has a shallow open box shape. Connection points can then be provided in the flange at the corners of the element.

As an alternative to integral formation of the reinforcing portions with the rest of the facing element, the reinforcing portions can be provided by means of a member which may be formed of a different material from that of the remainder of the element. This may be attached to the outside of the element for example in the form of an external brace, but, at least in the case of cast concrete elements, it is preferred to locate it at least partly within the facing element. This may be achieved by casting the reinforcing portion in place.

A further possibility provided by the present invention is that the stiffening effect of the reinforcing portion allows the use of plates or sheets e.g. of metal such as steel to form the facing elements. Such elements may be much thinner than those made of concrete. Again, there are various ways in which the reinforcing portions may be formed, including casting or rolling them integrally with the facing. However, it will often be desirable to form metal facings from lengths of sheet metal. The reinforcing portions may then, if desired, be formed by bending the metal, eg by using a press. This is most conveniently done near the edges of the panel. It is preferred to bend all of the edges in by about 90 degrees. Preferably each bend is a similar distance from the respective edge of the panel to form a peripherally extending rim, so that the resultant facing element has a shallow open box shape.

When an arrangement having such a bent portion is used, it will generally be desirable to provide the connection point in the form of a discrete member or assembly which is attached to the reinforcing portion. In the preferred shallow-box construction, the connection point is located at a corner where the structure is strongest. If a number of assemblies is to be provided, they may each be located at a corner. Although suitable assemblies may be bolted into place, it is preferred that they be welded. A typical construction will comprise two pin-like connectors at the upper corners and two pin-receiving connectors (eg. holes or tubes) at the lower corners.

An alternative construction has reinforcing portions in the form of separate (typically elongate) reinforcing members. These may then be secured to the facing by any conventional method, such as by bolts, rivets, adhesives or welding. Welding is, however, preferred since a connection can thereby be formed along most of the length of the reinforcing member, either continuously or at intervals eg. by spot-welding.

For aesthetic reasons, when the reinforcing portions are exposed they will normally be provided on the rear of the facing element. However, this is not essential, and in certain designs it may be preferable to make the reinforcing portions visible by locating them on the front.

The connecting point may be provided by a bracket or other connecting device cast into or otherwise secured to a reinforcing portion. Preferably, however, the connection point is provided by a connecting pin. It is then a simple matter during construction to locate a connector such as a hole, loop or hook formed in the end of an earth stabilising member around the connecting pin. Additionally, or alternatively, an adjacent panel may be attached by engaging the pin with a corresponding part of that panel.

In certain preferred embodiments, the connecting pin is connected to the rear of the facing element and there is preferably a clearance between the rear of the element and the pin. This construction is particularly useful when a sheet facing is employed. One way to achieve this construction is by forming the pin with a crank or by mounting it on a bracket. The clearance enables a stabilising member to be connected to the element without the requirement for a large gap between vertically adjacent elements to accommodate it.

Although such a cranked pin may be connected to the rear of a cast facing element, if it is desired to use such a pin, a preferred construction is partially to cast the pin into the facing element. Thus, the pin may comprise three parts: a first part cast into the facing; a second part projecting outwardly from the rear of the facing to provide an offset; and a third part providing the connection point.

In most constructions, the third part will be generally parallel to the first, and hence to the rear face of the facing element.

Although in the simplest facing element only a single connecting pin is necessary, if only this pin is used to connect earth stabilising member(s) to the facing element, then the element must be employed carefully to ensure that there is no resultant couple about the pin resulting from its connection to a stabilising member which could destabilise the structure. It is therefore preferred that a plurality of pins (eg. two) be provided and that each of these is connected to a stabilising member.

The connecting pin may be provided separately of the facing element, for example to be received in a hole formed at one end of a reinforcing portion. Alternatively, however, the connecting pin may be permanently fixed to the facing element.

The facing element will normally be constructed to cooperate with other facing elements to form the facing of an earth structure. It is highly advantageous that the connecting pin mentioned above is used to provide both the connection point to an earth stabilising member, and to provide connection to another facing element provided with suitable pin receiving means, such as a hole, recess, collar, loop or hook. The facing element therefore preferably comprises receiving means for receiving a connecting pin of an adjacent like element.

This dual use of the connecting pin ensures simplicity of design. The connecting arrangement of the pin in the receiving means is most appropriate for connecting vertically adjacent facing elements. During construction, it enables the element to be held in position by an element or elements below before an earth stabilising member has been attached to the upper element and anchored by having earth placed thereon.

Where the facing element is assembled with like elements to form a planar eg. vertical facing, then the connecting pin and receiving means will normally both be parallel to the plane of the facing. It may however be desired to have vertically adjacent facing elements at different angles, for example a lower element arranged vertically and an upper element tilted rearwardly. The connecting pin and receiving means arrangement may be used to accommodate such a change in angle, for example by arranging the connecting pin and/or the receiving means of the facing element at an angle (i.e. non-parallel) to the main plane of the facing element.

The facing element may have a lower edge designed to rest on the upper edge(s) of an element or elements below, for example with a deformable strip located between the edges. The pin and receiving means arrangement then assists with location and support of the element during construction, but will not normally transmit significant loads between adjacent elements. In certain preferred embodiments, however, the receiving means is arranged to provide an abutment against which the connecting pin of the adjacent like element may abut at least during construction. This is very useful since, although in a completed stabilised earth structure the weight of the facing elements is generally supported by their frictional engagement with the earth behind them (against which they are held by the earth stabilising members), such support is not available during the construction process.

Thus, since the facing element has a receiving means with an abutment against which a connecting pin of another element can abut, forces can be transmitted from one element to the next by means of the pin and receiving means rather than via the edges of the elements. Therefore, the edges of the elements do not have to be designed and constructed to withstand bearing against adjacent elements during construction. They can be spaced apart. In the case of a connection between vertically adjacent elements, the weight of an element or elements above causes the connecting pin to be loaded in axial compression. A further advantage is that in a completed structure there is less likelihood that relative movement of adjacent elements will result in damage to the elements. Moreover since the edges of the elements need not directly inter-engage, there is much greater freedom in the choice of element shapes, and, apart from the connecting pins and receiving means, the elements can be made to greater tolerances. A further advantage is that no interlocking formations such as tongues, grooves or lips are required along the edges. Thus, the edges may be straight from front to back, as viewed in a typical cross-section, although the edge profile may differ locally in the vicinity of a connecting pin or receiving means.

It will be appreciated from the foregoing that various advantages stem from the arrangement in which the receiving means provides an abutment against which the connecting pin of an adjacent like element may abut eg. during construction.

The connecting pin and receiving means arrangement for connecting facing elements may be designed such that the pin abuts against a rigid member and such an arrangement will be suitable for use in low cost applications or where a comparatively short design life is appropriate. However, preferably, the receiving means or the connecting pin comprises a deformable member, such as a block or pad of elastomeric material, for example rubber, plastics, cork or the like. The purpose of such a deformable member is to accommodate at least a degree of relative movement between the facing elements making up a facing of a structure as a result of settlement of the earth of the structure and also to provide a degree of tolerance in the fitting of the elements. The deformable member may be provided separately of the facing element for assembly therewith during construction, or it may be adhered to the facing element ready for assembly.

Since the reinforcing portions extend substantially across the facing element, in accordance with the invention, they are ideally suited to accommodate forces arising from the element's interconnection to other elements, as well as those which occur as a result of the connection to the stabilising member. In particularly preferred embodiments, therefore, the connecting pin is provided at one end of the reinforcing portion and the receiving means is provided at the other end thereof.

As previously discussed, the reinforcing portions strengthen the facing element and therefore assist in resisting the forces placed on the facing element, eg. due to the earth mass bearing against its rear face. It will be appreciated that this construction allows much more flexibility in the design of the parts of the facing element which are visible in use. This makes much more attractive the use of non-conventional materials such as steel, plastics or composites for some or all of the facing part of the element, allows for greater freedom in the choice of element shapes for aesthetic reasons and can also lead to savings in material and fabrication costs.

The connecting pin and receiving means are preferably separate members at opposite edges of the facing element, linked for load transmission by a respective reinforcing portion, as mentioned above. Alternatively, the connecting pin and the receiving means of the facing element are directly interconnected to define an elongate member. They may thus conveniently be formed integrally so that in combination they form a respective reinforcing portion, or a major part of it.

One preferred way in which to form such a directly interconnected connecting pin and receiving means (the "elongate member") is to provide an elongate pin having a pin receiving means such as a hole formed in, or a tube or collar provided around, one end thereof. This provides a simple structure which enables forces to be transmitted from the pin and associated pin receiving means directly to the reinforcing portion and thereby to the remainder of the element. During construction, this arrangement allows the weight of one element to be transmitted directly through the reinforcing portions of the lower elements.

Since connection points are formed at the corners of the facing elements, a facing assembled from the facing elements may have each element in direct alignment with the one below. This arrangement allows curved facings to be provided easily.

Although the invention is applicable to facing elements having a wide range of sizes, they are preferably relatively small, for example square panels 0.5m by 0.5m or 0.85m by 0.85m, or rectangular panels 0.6m in height by 0.9m wide, or 0.6m by 1.2m, or 0.5m by 0.7m, or 0.5m by 1.0m. Such small dimensions can combine with the small thicknesses which are achievable to give low weight facing elements which are easy to manoeuvre during construction. Preferred concrete facing elements may have a thickness less than or equal to 100mm, more preferably less than or equal to 80mm or even 50mm or less. Facing elements of other materials may be substantially thinner. Small scale lifting equipment can be used and this saves costs. In addition, with smaller elements the height thereof can conveniently be equal to the vertical spacing between earth stabilising members, in contrast to larger elements which often require two vertically spaced attachment points at the rear.

Various types of earth stabilising member may be used with the facing element, for example the metal strips known from GB-A-1 324 686 or GB-A-1 563 317, the polymeric strips or metal "ladder" strips known from WO 94/23136, or the metal grids also known from WO 94/23136. If the connection point of the facing element is used for connection to a stabilising member and is provided by a connecting pin, then the connection of a strip or grid to the facing element may be in accordance with the teachings of the above-mentioned documents. In one preferred arrangement, there is provided a metal bar which passes round the connecting pin of the facing element and is connected, eg. welded directly to a stabilising member in the form of a metal strip. This is a particularly economical way of connecting the facing element to an earth stabilising metal strip. The metal bar may loop round a single connecting pin, or it may loop round two or more connecting pins, either belonging to the same facing element or to adjacent facing elements. By looping the metal bar round more than one connecting pin, this advantageously distributes the loading of the stabilising member to spaced locations on the facing.

In a preferred construction, a recess is formed in the element at least at the connection point. The front end of an earth stabilising member may then be received in the recess and e.g. secured to a connecting pin. This allows the edges of vertically adjacent facing elements to abut or be closely spaced without fouling the stabilising member or being visible between the panels. In the shallow box construction referred to above a similar result may be obtained by in-setting the rim at least in the region of the connecting pin. The provision of a recess is particularly useful because the same pin is used to form a connection to an earth stabilising member and to an adjacent facing element. Such a recess is thus advantageous with both metal and concrete facing elements.

In order to secure horizontally adjacent elements together, an earth stabilising member may be connected to two adjacent elements. Alternatively, or additionally, separate connectors may be used which are interconnected with adjacent elements' connection points. These may take the form of a plate having two holes to receive connecting pins. This construction is advantageous because it ensures correct lateral spacing of the facing elements. A predetermined degree of tolerance can be allowed for by forming the holes slightly over-size. If desired, a third hole or other connection means may be provided for co-operation with an earth stabilising member. Preferably, the facing element has a recess in an upper or lower edge thereof, the recess extending to a side of the facing element. This allows the front end of an earth stabilising member or a separate connector to locate in the recesses of laterally adjacent facing elements and interconnect their connection points.

The correct lateral spacing of facing elements can be determined by the front end of an earth stabilising member, by forming the member with two laterally spaced points for attachment to the facing and a portion extending laterally between those points. With such an arrangement, the earth stabilising member can advantageously be used to define the correct relative position of adjacent facing elements. By providing the lateral portion between the attachment points, which in use is preferably in the same general plane as the facing, the lateral spacing of the facing elements can be maintained fairly precisely.

The lateral portion may be provided separately of the rest of the earth stabilising member and assembled therewith during installation of the facing or alternatively may be a fixed or integral part of the rest of the earth stabilising member.

Preferably, the attachment points are openings, which may be in the form of holes in a plate portion of the stabilising member, or in the form of loops. In the latter case there may be two loops in a continuous bar, thereby avoiding the need for a weld at an end of the bar. Alternatively two bar portions may be bent round to form respective loops, the ends of the bar portions being fixed together, e.g. by welding.

As mentioned above, it is desirable to provide a deformable member between adjacent facing elements, to cope with relative movement of the elements caused by earth settlement. In a preferred arrangement, the front end of an earth stabilising member provides the deformability.

The deformability may be provided by a block or pad of deformable material, for example rubber, plastics cork or the like, which may be provided separately of the rest of the earth stabilising member and assembled therewith during installation of the facing elements or alternatively may be fixed to the rest of the stabilising member in advance, e.g. by adhesive. It is then not necessary to provide a separate deformable member elsewhere on the edges of the facing elements. If the facing elements are connected to each other by a pin, then an annular deformable pad can locate round the pin.

In one preferred arrangement, the deformability may be provided by an arrangement in which the front end of the earth stabilising member is bent to form a spring. Thus no additional material is required to provide deformability. The spring may take various shapes, e.g. a flattened "C"-shape in side elevation. If however the front end is in the form of at least one loop, then this can provide both a spring and an opening through the loop for receiving a suitable portion of a facing, such as a pin. Such an opening is preferably arranged vertically, to receive e.g. a vertical pin. The loop can effectively form a coil of the spring. Overlying portions of the member forming the loop will be spaced apart in an unstressed condition, to allow for compressive deformation.

A single loop may be provided, but preferably the earth stabilising member has a pair of loops and a portion extending laterally therebetween. The advantage of this is discussed above.

Certain embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:

Figure 1 is a rear elevation of a first embodiment of facing element;

Figure 2 is a schematic view of a front elevation of a facing structure using a number of facing elements as shown in Figure 1;

Figure 3 is a partial perspective rear view of the first embodiment of facing element;

Figure 4 is a connecting pin assembly for use in the first embodiment;

Figure 5 is a connecting tube assembly for use in the first embodiment;

Figure 6 is a schematic perspective view showing the interconnection of panels of the first embodiment and an earth reinforcing member;

Figure 7 is a rear perspective view of a second embodiment of facing element;

Figure 8 is a side elevation, partly in section, of the connection between two vertically adjacent facing elements of the second embodiment;

Figure 9 is a horizontal cross-section of the connection of Figure 8;

Figure 10 is a plan view of a sheet for forming the second embodiment of facing element, before bending;

Figure 11 is a rear elevation view of a third embodiment of facing element;

Figure 12 is a vertical section on the lines A-A of Figure 11;

Figure 13 is a horizontal section on the lines B-B of Figure 11;

Figure 14 is a vertical cross-section through the connection between two vertically adjacent elements of the third embodiment;

Figure 15 is a perspective view of the front end of an earth stabilising element;

Figure 16 is a perspective view of an alternative form of earth stabilising member; and

Figure 17 is a perspective view of a further alternative form of earth stabilising member, together with a corner of a facing element to which it is to connect.

The first embodiment of facing panel 90 is illustrated in Figures 1 to 5. It is formed of 4mm thick plain steel sheet and is suitable for structures of up to 6m in height. Thinner metal may be used for low structures or thick metal for higher structures. The panel 90 has at its edges bent portions 91 which are bent backwards at 90° to the central part which is a square. The bent portions extend rearwardly by about 30mm. Connecting pins 92 are provided at the upper corners and connecting tubes 93 are provided at the lower corners. In use panels 90 are connected together to form a facing as shown in Figure 2, with the connecting pins 92 of each facing panel 90 being received in the connecting tubes 93 of the panel above. It will be noted that the vertical edges of the panels are aligned, rather than being offset to form a brickwork effect.

The construction of panel 90, which is effectively a shallow open box, can be seen from Figure 3. The bent portions 91 stiffen the panel so that it can withstand earth pressures without other reinforcement. At each corner a section of the folded back edge 91 is cut-away to receive connecting pin assemblies 95 and connecting tube assemblies 96.

Figure 4 shows a connecting pin assembly 95. It comprises a strip of steel 98 similar to that forming the remainder of the facing panel which has a bore through which the connecting pin is located. Initially these components are tack-welded together. The strip is bent so that in the finished panel a recess 97 is provided around the connecting pin to receive the end of an earth stabilising member. This prevents the stabilising member fouling the panel above or being visible through the gap between adjacent panels.

The connecting tube assembly 96 (Figure 5) is formed from a steel plate 99, which is also of similar thickness to the facing panel. A tube 93 is welded to the lower face of the plate.

As may be seen from Figure 3, the assemblies are located in the respective corners of the facing element so that the connecting pin 92 is directly above the tube 93. The assemblies are first tack welded into place and then the entire facing element is welded together. It will be noted that the lower end of the connecting pin is bent towards the vertical bend-line of the facing element (which it abuts) and is welded thereto. The tube assembly 96 is welded to the front of the panel and the tube itself is located within a hole 102 in the base edge 91' of the panel. The location of the pins 92 and the tubes 93 in the corners of the panels, where there are three mutually perpendicular components provided by the main panel body and the rim forming components (i.e. the bent portions 91 and the strips 98), creates a very strong connection point.

In a facing structure, the connecting pins 92 and connecting tubes 93 of vertically adjacent panels are inter-engaged. A rubber pad will generally be located within tubes 93 to accommodate settlement. However, the interconnection of horizontally adjacent panels is significantly different.

As shown in Figure 6, a metal plate 105 having two holes 106 formed therein is located over adjacent connecting pins 92, thereby connecting them together. The plate 105 is located in recess 97 referred to above and keeps the elements the correct distance apart. The holes in the plate are larger than pins 92 by a predetermined amount (5mm in this case) in order to accommodate a given amount of expansion and/or settlement of the structure. An earth reinforcing member in the form of an 8mm diameter steel wire 110 is then passed around the pins 92. A further layer of panels may then be added with their connecting tubes 93 engaging with the pins 92.

Since the vertical edges of the panels are aligned, rather than being offset to form a brickwork effect, it is easier to form a curved facing structure than is possible with offset panels. The result will also often be more attractive since, with the connection points being at the edges of the panels, they provide good pivot points.

The second embodiment of facing panel 90 is shown in Figs. 7 to 10. It is formed of 3mm plain steel sheet and has overall dimensions of 0.6m by 0.6m. The panel has a shallow open box shape having at its edge bent portions 91 bent backwards at 90° to a main central portion 130. The bent portions extend rearwardly by about 60mm. As shown in Fig. 10 the vertically extending bent portions each have one bend line 111. The horizontally extending bent portions each have three bend lines 112, such that when the sheet is bent a horizontally extending lip 113 is formed with a horizontally extending ledge 114 behind the lip 113 and vertically inset therefrom. A horizontally extending recess 97 is thus defined behind vertically adjacent lips (see Fig. 8) for receiving the front end of an earth stabilising member. As shown in Fig. 7 the adjoining end edges of the bent portions 91 are welded at 115.

A connecting pin assembly 95 is provided at each upper corner of the facing panel 90 for connection with a hole 116 provided in the lower ledge 114 at the lower corners of a panel above. A connecting pin 92 is welded at its lower end into the vertically extending bend 111 between the central portion 130 and a vertically extending bent portion 91. The pin 92 projects vertically through a hole 117 in the upper ledge 114.

The third embodiment of facing panel is shown in Figs. 11 to 14. It is formed of cast concrete and has a main central portion 130 surrounded by a thickened flange 131. The flange 131 extends about the periphery of the panel and effectively provides four reinforcing portions extending across the panel, two vertically and two horizontally. The panel is formed along its upper and lower edges with respective horizontally extending lips 113 and ledges 114. As with the embodiment of Figs. 7 to 10 the ledges 114 are vertically inset from the lips so as to define a horizontally extending recess 97 behind vertically adjacent lips 113 (see Fig. 14) for receiving the front end of an earth stabilising member. A chamfer 135 can optionally be provided at the front edge of the flange 131, about the entire periphery of the panel, as seen in Fig. 14.

Adjacent the corners of the panel, vertical blind bores are formed by casting plastic tubes 100 into the flange 131. During assembly loose connecting pins 92 are inserted in the tubes 100 to locate one panel above another. A vertical gap 140 is allowed between the top of the pin and the upper end of the tube 100 of an upper panel, to allow some play for relative vertical movement of the panels. In this example, the gap is 5mm.

The example of facing panel shown in Figs. 11 to 14 is 0.5m square, with a maximum flange 131 thickness of 100mm and a central portion 130 thickness of 40mm. Other dimensions are of course possible, but this example serves to illustrate the thinness of the central portion, and thus savings in weight, compared to known panels.

The front end of an earth stabilising member 120 is shown in Figs. 8, 9, 14 and 15. The front end is formed from a continuous bar into two loops 121 joined by a lateral bar portion 122. The bar extends rearwardly as two parallel elongate portions 123 interconnected at longitudinal intervals by cross-members 124. Each loop 121 engages round a connecting pin 92 in the recess 97 between vertically adjacent facing panels 90. The lateral spacing of the loops 121 is determined and maintained by the length of the lateral bar portion 122, so that the front end of the earth stabilising member can usefully define the lateral spacing between laterally adjacent panels.

Each loop 121 is formed with a vertical space 125 between the lateral bar portion 122 and the rearwardly extending portion 123, so that the loop effectively forms a one coil spring able to compress or expand if there is relative movement of vertically adjacent facing panels caused for example by earth settlement. Thus, for example the lips 113 may initially be spaced apart by 5mm and the ledges 114 behind by 20mm. The earth stabilising member may be formed from 8mm diameter bar with a vertical space 125 of 4mm at the loop.

The front end of another stabilising member 120 is shown in Figure 16. This differs from the earth stabilising member of Figs. 8, 9, 14 and 15 in that the lateral bar portion 122 is formed by welding together two bar end portions. As before the lateral bar portion is vertically spaced from the rearwardly extending portions 123, so as to form a deformable spring.

The front end of a further stabilising member is shown in Figure 17. In this case the rearwardly extending portion 123 of the member is in the form of a flat ribbed strip, as known from GB-A-1 563 317. The front end of the strip is welded to a laterally extending plate 122 formed with laterally spaced holes 121. A facing panel 90 has an upwardly projecting connecting pin 92 on which one of the holes 121 engages to attach the earth stabilising member to the facing element. An annular deformable pad 140 is engaged on the pin, so as to provide the earth stabilising member with a deformable front end. The pad 140 could alternatively be adhered to the earth stabilising member in advance of assembly.

In a modification of the Fig. 17 arrangement, the rearwardly extending portion 123 could be in the form of a tie-bar secured at its rear end to an anchor buried in the earth behind the facing.

Claims

A facing element (90) for use in a stabilised earth structure, the facing element comprising:

a central portion (130),

a plurality of reinforcing portions (91;131) extending substantially across the facing element and converging at corner regions of the facing element so as to define a flange extending substantially about the periphery of the facing element outwardly of the central portion (130),

characterised by

a dual function connection point at a said corner region for connection to a vertically adjacent facing element and to an earth stabilising member (110;120), the connection point including either a connecting pin (92) or a hole (93;116;100) for receiving a connecting pin, such that, when the facing element is assembled in said stabilised earth structure with said vertically adjacent facing element, the facing element is connected at said corner region to said vertically adjacent facing element by said connecting pin.
A facing element (90) as claimed in claim 1, wherein the connecting pin (92) is permanently fixed to the facing element.
A facing element (90) as claimed in claim 2, comprising a metal sheet having the connecting pin (92) fixed thereto.
A facing element (90) as claimed in claim 1, wherein the connecting pin (92) is provided separately of the facing element.
A facing element (90) as claimed in any preceding claim, wherein the reinforcing portions (91) have been formed by bending part of the facing element.
A facing element (90) as claimed in any preceding claim, wherein the central portion (130) is formed integrally with the reinforcing portions (91;131).
A facing element (90) as claimed in any preceding claim, comprising a recess (114) in an upper or lower edge of the facing element, the recess extending to a side of the facing element.
An earth structure having a facing comprising facing elements (90) as claimed in any preceding claim, wherein at least one earth stabilising member (110;120) is connected to the facing elements.
An earth structure as claimed in claim 8, wherein the facing elements are four sided and have four corner regions and wherein vertically adjacent facing elements are arranged in alignment with each other.
An earth structure as claimed in claim 8 or 9, wherein two connecting pins at two laterally adjacent corner regions of two laterally adjacent facing elements are connected to a common earth stabilising member.
An earth structure as claimed in claim 10, wherein said earth stabilising member (110;120) comprises a pair of laterally spaced attachment points (106;121) for attachment to said two connecting pins, and a portion (105;122) extending laterally between the attachment points to define the lateral space therebetween.
An earth structure as claimed in claim 11, wherein the lateral portion (105;122) is provided separately of the rest of the earth stabilising member (110;120) and assembled therewith.
An earth structure as claimed in claim 11, wherein the lateral portion comprises a connector plate (122) having two laterally spaced holes (121) which provide the attachment points, each hole (121) receiving a connecting pin (92) of respective laterally adjacent facing elements (90).
An earth structure as claimed in claim 13, wherein the connector plate has a third hole or other connecting means for cooperating with the rest of the earth stabilising member.
An earth structure as claimed in claim 11, wherein the attachment points (121) of said earth stabilising member are openings formed by two loops in a continuous bar.
An earth structure as claimed in any of claims 8 to 15, wherein the earth stabilising member (120) is provided with a deformable front end so that in use it can form a deformable abutment between vertically adjacent facing elements of the structure.
An earth structure as claimed in claim 16, wherein the front end of said earth stabilising member (120) is bent to form a spring.
An earth structure as claimed in claim 17, wherein the front end of said earth stabilising member is in the form of at least one loop (121).
An earth structure member as claimed in claim 18, wherein the earth stabilising member comprises a pair of loops (121) and a portion (122) extending laterally therebetween.