GB2261244A - Facing element and facing system - Google Patents

Abstract

A facing element 1 for a stabilised earth structure comprises a connecting device 15 for connection to a stabilising element 30, a support member 2 for supporting earth and a pair of laterally spaced bearing members 3 to support or partly to support a further facing element 1 thereabove, the support arrangement of the bearing members 3 being such that during construction of the structure relative forward and rearward, rotational and lateral positional adjustment is permitted between the facing element 1 and the further facing element 1 thereabove. A facing system is built up from a plurality of superimposed rows of such facing elements. Other embodiments of facing elements are described (figs 6, 11, 14 & 15). <IMAGE>

Description

FACING ELEMENT AND FACING SYSTEM The present invention relates to a facing element and a facing system for an earth structure of the type stabilised by stabilising elements extending in the earth, such stabilising elements comprising for example ties secured to deadmen anchors or more preferably strips or sheets which stabilise the earth by frictional interaction therewith.

It is known from European Patent Application No. O 345 077 to provide a facing system for a frictional stabilised earth structure comprising an assembly of facing elements each having a sloping rectangular facing panel with a horizontal upper edge disposed forwardly of a horizontal lower edge, the facing panel being bolted to a pair of generally rectangular laterally spaced side panels. The side panels are stacked up one upon another so as to present the appearance of a column when the facing system is viewed in front elevation. Although the facing system may be curved in plan view, the amount of "turn" or angle between two facing elements is limited by the need for each side panel to sit on the side panel below.When the facing system slopes to the rear, with each row of facing elements disposed rearwardly of the row below, the radius of the plan curve varies with height. Since each side panel sits on a side panel below, there is little or no scope for lateral adjustability, so that to cope with the varying radius special facing elements of different lateral dimension must be provided.

Viewed from one aspect the present invention provides a facing element for a stabilised earth structure, comprising a connecting device for connection to a stabilising element, a support member for supporting earth and a pair of laterally spaced bearing members to support or partly to support a further facing element thereabove, the support arrangement of the bearing members being such that during construction of the structure relative forward and rearward, rotational and lateral positional adjustment is permitted between the facing element and the further facing element thereabove.

Viewed from another aspect the present invention provides a facing system for a stabilised earth structure, comprising a plurality of superimposed rows of facing elements, the facing elements having a connecting device for connection to a respective stabilising element, a support member for supporting earth and a pair of laterally spaced bearing members to support or partly to support a facing element in the row above, the support arrangement of the bearing members being such that during construction of the structure relative forward and rearward, rotational and lateral positional adjustment is permitted between the facing elements and the facing element thereabove.

Viewed from another aspect the invention provides an earth structure having a facing system as described herein, and having earth stabilising members attached to the facing system.

Thus, the position of the element in the forward and rearward direction may be selected in accordance with the desired batter or slope of the facing system; for example the facing elements may be in general vertical alignment to give a vertical facing system, or the facing elements of each row may be rearwardly displaced relative to the row below to give a rearwardly sloping or battered facing system, at a slope of e.g 1:4, 1:3 or 1:2 (horizontalvertical). Additionally, or alternatively, a rearward slope of the facing system may be achieved by tilting the whole set of elements to the rear.

The further adjustability of the position of the facing element results in certain significant advantages. The position of the facing element in the lateral direction may be selected to vary the lateral spacing of the facing elements. This may be particularly useful where it is desired to vary the spacing of the stabilising elements to be attached to the facing elements and thus the density of the stabilising elements. This feature of adjustability may also be desirable for architectural reasons i.e. to vary the aspect of the facing system. The permitted amount of lateral adjustment may be at least 5cm, or possibly locum, 15cm or 20cm.

The third factor concerning the position of the facing element relative to the one above, is the desirability of varying the angle between the facing elements as viewed in plan to allow the facing system to be curved in plan. Where the facing system as a whole slopes to the rear, the radius of the plan curve will vary with height, and will thus vary from row to row.

It is therefore particularly desirable for the facing elements to accommodate a wide range of angles relative to adjacent elements. Thus the support arrangement of the bearing members is preferably such as to permit an angle between adjacent elements in the range from 0 (no curvature in plan) up to +30 (with the elements angled either to form the facing system with a convex or a concave plan curve). As the radius of the plan curve varies with height, it is necessary to vary the lateral spacing between the facing elements. This is of course permitted by the design of the elements.

A preferred embodiment comprises a facing system having a curve in plan view and a rearward batter, in which substantially all the facing elements have the same lateral dimension and are at different lateral spacings depending on their vertical position in the system.

The bearing members will normally be provided with upper bearing surfaces which support lower bearing surfaces of the facing element above, either directly or with an intervening bearing pad. At least one of the upper and lower bearing surfaces is sufficiently large to permit the desired range of different positions of a facing element relative to the facing element(s) above.

Preferably, the upper bearing surfaces and/or the lower bearing surfaces are formed with a lateral dimension at least equal to (and more preferably greater than) the dimension in the forward and rear direction. In a preferred embodiment, each lower bearing surface of the facing element is generally elongate with the longitudinal axis extending laterally of the facing element. This provides substantial scope for lateral adjustability Preferably, the upper bearing surfaces of the bearing members are located substantially in only the rear half of the facing element and the earth support member extends forwardly of the upper bearing surfaces.

In fact, this arrangement is independently advantageous.

Thus, viewed from another aspect the present invention provides a facing element for an earth structure, comprising a support member for supporting earth, and a pair of laterally spaced bearing members each having a bearing surface for supporting a further facing element thereabove, the bearing surfaces being located substantially in only the rear half of the facing element and the earth support member extending forwardly of the bearing surfaces.

With such an arrangement, because the support member of a facing element extends forwardly of the rearwardly located bearing surfaces, the connection between the element and an element above is relatively inconspicuous when the facing is viewed in front elevation. Furthermore, earth placed on the support member of the facing element located forwardly of the bearing portions, can enable plants to grow in a forward position so as to conceal or at least partly conceal the bearing members. Thus the facing system in front elevation can present an array of plant growth areas located forwardly of the connections between a facing element and a facing element above, avoiding the appearance of a continuous vertical column created by upright bearing members one above another.

In some circumstances, for example when constructing an underpass, it may be desired to leave the earth unplanted. Thus the term earth as used herein is intended to cover particulate material generally as well as material which is suitable for plant growth.

In certain preferred embodiments, the bearing surfaces are located substantially in only the rear one third of the facing element.

It is preferable for the laterally spaced bearing members to extend upwardly from the earth support member. Thus the bearing members can serve to retain laterally earth supported on the member, at least at its rear. This permits each facing element to be placed at a substantial angle to an adjacent element, without earth falling from the side of the element, thereby enabling sharp curves of the facing system in plan view.

Furthermore, as the bearing surfaces of such upwardly extending bearing members will normally be provided at the upper ends of the bearing members, the earth support member of a higher facing element placed on the bearing surfaces will tend to overhang and thus conceal them.

The bearing surfaces may for example slope slightly downwardly in the forward direction (for ease of manufacture as explained below), so that an element above may be supported on an intervening bearing pad, of e.g. timber or preferably an elastomer such as EPDM, in order to correctly position the element above.

The bearing members provided with the bearing surfaces will themselves normally be located at the rear of the facing element. By providing an arrangement in which substantially no part of the facing element extends rearwardly of the bearing members, the size and weight of the facing element is advantageously kept to a minimum. This reduces costs both in terms of the amount of material, normally concrete, used to form the facing element, and in terms of manoeuvrability during construction which is assisted by reduced weight.

In preferred facing systems, each facing element is supported by the bearing members of the two adjacent facing elements in the row below. Thus the facing elements in a row may be laterally spaced and positioned above corresponding lateral spaces between facing elements in the row below. Earth placed on the support member of each facing element will then form an open sloping surface from the support member through the lateral space in the row above, to the facing element in the row above the lateral space. The angle of the open sloping surface may be anything up to the natural angle of repose of the earth, for example an angle of stand' 0.67 to the horizontal, i.e., a slope of 3:2 (horizontal:vertical), and the dimensions of the facing elements will be selected appropriately.However, as the earth will normally receive plants, it may be possible to provide steeper slopes, providing the slope is stabilised prior to establishment of plant growth.

Thus the angle may in general vary between tan~1 0.4 and tan'g 0.8 to the horizontal. Steeper angles are desirable if a minimum amount of the facing elements and a maximum amount of plant growth area are to be exposed.

Very steep angles may not be desirable due to the risk of erosion by running water An advantage of the system in which facing elements are laterally spaced is that the designer is given substantial freedom over the shape of the earth support members, since the profile at the sides of these members is not restricted by abutment against adjacent members.

Furthermore, if the facing is curved in plan view it is necessary to place laterally adjacent facing elements at an angle to each other, and this is made easier in an arrangement where such elements are laterally spaced.

Thus sharp curves in plan view can be achieved without specially shaping the side profile of the earth support members.

It is possible for the lower bearing surface or surfaces of the facing element simply to be the lower surface of the earth support member. This provides substantial scope for adjusting the position of the facing element on the upper bearing surfaces below. In a preferred embodiment, each bearing member of the facing element is formed with a lower bearing surface substantially in vertical alignment with the upper bearing surface of the bearing member. This ensures that the main loads, i.e. the weight of the facing elements in the row or rows above, are transmitted in compression. Where concrete is used to form the facing element, as will normally be preferred, this arrangement allows steel reinforcement to be omitted, since tensile forces are kept to a minimum. To assist alignment of the post of one facing element with the one below, suitable locating means may be provided.For example the facing element may include a fin projecting downwardly from its earth support member.

The bearing members of the facing element may be laterally spaced apart by the full width of the facing element. Alternatively, the bearing members may be inwardly spaced from the sides of the facing element, whereby the earth support member projects laterally outwardly beyond the post on each side.

In a preferred embodiment, the earth support member has no side walls and has side edges which, in use, are to be positioned adjacent to the side edges of adjacent facing elements. The side edges may be directly adjacent or they may be laterally spaced from each other. If they are directly adjacent, a continuous earth supporting ledge is formed. With such an arrangement, if the facing system includes a curve in plan view the earth support members of laterally adjacent facing elements where the curve is formed will need to be appropriately profiled, e.g. part-circular, to accommodate the angle between the elements.

The earth support member of the facing element preferably extends from front to rear at least as far as the rear half of the facing element. Thus a large planting area may be provided relative to the overall depth of the facing element and this involves economical use of the material forming the facing element. The earth support member may extend rearwardly to a region generally in line with the front of the bearing members, but preferably it extends as far as substantially the rear of the facing element, to provide a maximum size of planting area.

The earth support member of the facing element is preferably substantially horizontal in use, so that the amount of the member which is seen in front elevation is kept to a minimum. Preferably however at least part of the upper surface of the support member will slope downwardly to the rear to assist in retaining earth thereon. This also permits drainage to the rear of the element, where appropriate drainage material may be provided. In a preferred embodiment, the upper surface of the support member is generally concave, whereby in use water drains to the centre of the surface and then rearwardly.

The earth support member may include side walls to restrain earth on the member from lateral displacement.

The side walls may have an upper surface which follows the exposed slope of the earth on the member so that plant growth can at least partially cover the side walls. The side walls may advantageously be formed as a forward continuation of the bearing members of the facing element. The provision of side walls assists the ability of each element to be at an angle to the adjacent element, as the earth on the support member of each element is effectively self-contained.

It may also be desired to provide means for containing the earth at the front of the support member, such as a front wall. This enables greater depths of earth to be placed near the front edge of the member, thereby assisting plant growth and preventing drying out in this region. If the earth is not to be planted, the front wall helps to prevent erosion. Furthermore, as the element provides a substantially self-contained earth receptacle, one element may easily be placed at an angle to the next, allowing sharp curves in plan view.

It may be desired to provide the facing element with a rear beam member extending laterally between the bearing members, upwardly spaced from the earth support member. Such a beam member can serve to prevent forward passage of backfill on to the support member, thus separating "technical" backfill and the earth on the support member, which is preferably plantable. The upward spaing of the beam member from the support member allows plants to draw water from the backfill.

Moreover, such a beam member can provide a strengthening function.

The facing element may also have a rear wall extending below the earth support member to define a downwardly projecting fin which prevents forward passage of backfill. This can also serve to increase the vertical spacing between rows of facing elements since the open sloping earth surface can then extend upwardly from a support member of one element to the bottom of the fin of another, higher element, rather than to the bottom of the support member of the higher element. The fin may also be provided with a central forwardly extending web which allows the element to stand freely or with the aid of a wedge e.g. on a foundation. The web may extend between the fin and the earth support member, thereby reinforcing the earth support member against the load of the earth to be placed thereon.

Furthermore, the fin can assist in locating an element in position, as mentioned above.

The earth behind the facing system is preferably stabilised by sheets or strips of e.g. geotextile or by metal strips. In general, where strips are used, there will be one strip per facing element. The connecting device, for example an attachment lug, is preferably partly embedded in the material of the rest of the facing element. It may be centrally located on the facing element, for example at the level of the earth support member. This may therefore include a thickened portion at its rear for embedding the connecting device, which portion is preferably sloped on its upper surface to drain water away from the device, thereby protecting the stabilising element from water loaded with organic components.

The connecting device is particularly advantageous where geotextile stabilisation is used, since direct contact between the geotextile and a concrete facing element can be avoided. The alkanity of concrete can have an adverse effect on geotextiles.

The facing element is preferably cast or moulded in concrete, which need not be reinforced, in view of the ability of the facing elements to transmit the principal loads, resulting from the weight of the elements above, in compression.

Preferably the earth support member and the bearing members of the facing element are integrally moulded in one piece. The shape of the facing element is preferably such as to permit removal from a mould by inversion thereof on to a receiving surface and lifting of the mould In fact, these features are independently advantageous Thus, viewed from a further aspect, the present invention provides a facing element for a stabilised earth structure, comprising a connecting device for connection to a stabilising element, a support member for supporting earth and a pair of laterally spaced bearing members to support or partly to support a further facing element thereabove, the support members and the bearing members being integrally moulded in one piece and the shape of the facing element being such as to permit removal from a mould by inversion thereof on to a receiving surface and lifting of the mould.

The present invention also provides a method of moulding a facing element for a stabilised earth structure, the facing element comprising a support member for supporting earth and a pair of laterally spaced bearing members to support or partly to support a further facing element thereabove, the method comprising placing moulding material, such as concrete, in a mould to form the support member and the bearing members, locating in said moulding material a connecting device for connection to a stabilising element or locating in said moulding material a recess for receiving such a connecting device, and removing the moulding material from the mould by inversion thereof on to a receiving surface and lifting of the mould.

By providing a self unmoulding facing element, the element can be immediately unmoulded after casting, and the mould is available for re-use. Easy removability of the element from the mould is preferably achieved by forming the facing element with no surfaces which are re-entrant relative to the direction of mould removal.

The surfaces of the facing element preferably are sloped or battered relative to the removal direction in such a way as to reduce resistance to removal. Thus when the mould is to be removed in the forward direction of the facing element, it is advantageous if the upper bearing surfaces of the element slope downwardly in the forward direction. For this reason, the intervening pads mentioned above are required between a facing element and an element above.

The mould material is preferably placed in the mould via an open top thereof and is then removed via the open top after inversion, as the mould is lifted.

In one preferred method, the connecting device is embedded in the moulding material and projects therefrom. The receiving surface may then be provided with an opening through which the connecting device may pass when the mould is inverted.

In another preferred method, the mould includes d portion for forming the recess for the connecting device. After moulding, the connecting device is positioned in the recess which is then filled with moulding material. The connecting device is then embedded in the moulding material and projects therefrom The shape of the facing element is also normally such as to enable handling with slings, no lifting inserts being necessary.

Certain preferred embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figs. 1 and 2 are perspective views respectively from above and below of a first embodiment of facing element; Fig. 3 is a perspective view of the first embodiment of the facing element supported in a sling; Fig. 4 is a cross-section of a facing system constructed of the first embodiment of facing element; Fig. 5 is a perspective view of the facing system; Fig. 6 is a front elevation view of a second embodiment of facing element, being a modified version of the first embodiment; Fig. 7 is a side elevation view, partly in section, of the second embodiment; Figs. 8, 9 and 10 are respective cross-sections of facing systems constructed of the second embodiment of facing element;; Fig. 11 is a perspective view of a third embodiment of facing element; Fig. 12 is a cross-section of a facing system constructed of the third embodiment of facing element; Fig. 13 is a plan view of a fourth embodiment of facing element, being a modified form of the third embodiment; Fig. 14 is a perspective view of a facing system constructed of a fifth embodiment of facing element; Fig. 15 is a perspective view of a sixth embodiment of facing element; Fig. 16 is a perspective view of a facing system constructed of facing elements in accordance with the sixth embodiment; Fig. 17 is another perspective view of the facing system constructed of facing elements in accordance with the sixth embodiment, the elements including earth thereon; Fig. 18 is a perspective view of part of a facing element during manufacture thereof; and Fig. 19 is a perspective view of the first embodiment of facing element during manufacture thereof.

Referring firstly to Figs. 1, 2 and 3, a facing element 1 comprises a support member 2 for supporting earth thereon, a pair of laterally spaced bearing members in the form of posts 3, a rear beam member 4 extending laterally between the posts at an upward spacing from the earth support member 2, a laterally extending rear fin 5 projecting downwardly from the earth support member, and a web 6 arranged centrally of the fin 5 and connecting it with the earth support member 2.

Each post 3 includes at its upper end an upper bearing surface 7 and at its lower end a lower bearing surface 8. The forward part of each upper bearing surface 7 is provided by a protuberance 9 so that the upper bearing surface is generally 'L' shaped in plan view. This increases the length of the upper bearing surface in the forward direction to assist in inserting bearing pads 10 (see Fig. 4) which may be provided to adjust the position of a facing element on the upper bearing surfaces of the facing elements below. Each lower bearing surface 8 is defined at the bottom of a laterally projecting wing 11 on the respective post 3, so that the surface is generally elongate with its longitudinal axis extending laterally of the facing element. This permits a substantial degree of freedom in lateral positioning of a facing element on the upper bearing surfaces of the elements below.

The earth support member 2 extends the full depth of the facing element from rear to front and includes a pair of surfaces 12 which slope downwardly towards a central surface 13 of the support member which slopes rearwardly to assist earth retention on the member.

Thus any water on the support member drains centrally towards the rear of the support member. Provided centrally at the rear of the support member 2 is a thickened portion 14 in which a connecting device 70 including an attachment lug 15 (see Fig. 4) is embedded for connection of a stabilising strip 30 which in use extends rearwardly into the earth backfill behind the facing element. The central web 6 includes an upper thickened portion 16 which also serves to accommodate the embedded attachment lug 15.

Fig. 3 illustrates the facing element 1 being carried in a sling 60. The two loops of the sling can be easily hooked under the opposite lateral ends of the facing element to suspend it in a stable manner without the use of special lifting inserts. The sling 60 engages underneath the earth support member 2 and/or the lower bearing surfaces 8 and can be easily located in this position because these parts of the element are upwardly spaced from the ground by the fin 5 and web 6.

The facing element of Figs. 1-3 has an overall width of 1 metre, a height of 0.586 metres, and a depth of 0.45 metres. The upper bearing surface has a depth of 0.45 metres. The upper bearing surface has a depth of 0.157 metres, including the protuberance 9 which has a depth of 0.057 metres; the upper bearing surface thus extends over about one third of the overall depth of the facing element. The weight of the facing element might typically be 100 kg +25%.

Figs. 4 and 5 show a facing system constructed using the facing elements of the first embodiment and illustrate how an open earth slope 20 extends from the front of each support member 2, through a lateral space 21 between facing elements 1 in the row of elements above, to the bottom edge of the rear fin 5 of a facing element in the next row above the lateral space 21. It will be seen that in each case a substantial part of the earth slope is disposed forwardly of the upper bearing surface 7, and that the rear beam member 4 is virtually buried within the earth.

As seen in Fig. 5, each planting area provided by an earth slope presents a generally hexagonal shape when the facing system is viewed in front elevation. Fig. 5 demonstrates how the earth support members of the facing elements project forwardly of the upper bearing surfaces of the members below, so that as plants grow the manner in which the facing elements are connected together towards the rear will become progressively obscured.

The second embodiment of facing element shown in Figs. 6 and 7 corresponds generally to that of the first embodiment except that the wings 11 of the posts 3 are omitted and the fin 5 is reduced in width.

Figs. 8, 9 and 10 show vertical sections through facing systems made up from the second embodiment of facing element. The overall rearward batter or slope 22 of the facing system shown in Fig. 8 is 1:4 (horizontal:vertical), the slope 23 of Fig. 9 is 1:3 and the slope 24 of Fig. 10 is 1:2.

Figs. 11 and 12 show facing elements according to a third embodiment. Each facing element 1 comprises an earth support member 2, a pair of laterally spaced bearing members in the form of upright posts 3, and a thickened portion 14 of the support member in which an attachment lug 15 for an earth reinforcement 30 is embedded. When the facing elements are assembled to form a facing system as shown in Fig. 12, the earth on the support members 2 has an open slope 31 at an angle of tan~1 0.67 to the horizontal (3:2, horizontal:vertical), whilst the overall slope 32 of the facing system is at an angle of tan~1 2 to the horizontal (1:2, horizontal:vertical). Bearing pads 10 are arranged between the upper bearing surfaces 7 of the facing elements and the lower surfaces 37 of the earth support members of the facing elements above.The reinforcements 30 extending rearwardly into the earth backfill are not quite horizontal but slope downwardly in the rearward direction at a slope of 100:4 (horizontal:vertical).

As seen in Fig. 11 the support member 2 projects laterally beyond the posts 3 on each side of the facing element. If the projection is such that the side edge of one support member will be directly adjacent the side edge of the support member of the adjacent facing element in the same row (as seen in Fig. 14), then in order to accommodate a curve in plan of the facing system it is necessary to form the support member side edge with a suitable profile. Thus Fig. 13 shows a fourth embodiment of facing element 1 having a support member 2 formed with a first side edge 33 of a concave part-circular profile and a second side edge 34 of a convex part-circular profile. This arrangement permits relative turning of the facing elements.

Fig. 14 shows a facing system made up of an assembly of facing elements 1 in accordance with a fifth embodiment, being a modified form of the third embodiment. The support member 2 of the facing element terminates generally at the front of the upright posts 3 thereby producing savings in the amount of concrete used. In order to strengthen the connection between the support member 2 and the posts 3, the support member is formed with a laterally extending rear rib 35. Fig. 14 illustrates how each facing element is supported by two adjacent upright posts of the pair of facing elements in the row below. The result of such a staggered arrangement is that the ends of alternate rows need to be finished with facing elements of half normal width.

Such a facing element 36 is shown in the bottom row of the facing system of Fig. 14.

Whilst the facing elements of the three embodiments shown in Figs. 11-14 may be of any convenient size, a typical facing element might have a width of 1 metre, a height of 0.4 metre and a depth of 0.5 metre. If the element is formed in plain concrete this would give a weight of around 60-80 kg.

Fig. 15 illustrates a facing element 1 in accordance with a sixth embodiment, whilst Figs. 16 and 17 show a facing system made up of facing elements 1 according to the sixth embodiment. Each element comprises a support member 2 having a pair of laterally spaced bearing members 3 each with an upper bearing surface 7. A distinctive feature of this embodiment is that it includes a perimeter wall 40 extending round the entire support member 2 to contain earth thereon. The perimeter wall includes a rear wall 41, two side walls provided by the bearing members 3 and a front wall 43 which interconnects the side walls.

It will be seen from Figs. 16 and 17 that the facing elements are assembled in rows, with a lateral space 21 between adjacent elements in a row, the space being occupied by an earth slope, similar to the other embodiments. If desired, each facing element may be turned relative to the adjacent element, for example to provide a facing system having a convex curve in plan view. The fact that the earth is contained within the perimeter wall 40 of each facing element enables relative turning of the facing elements without earth loss. The facing elements of Figs. 15-17 are heavier than those of Figs. 11-14 and would have a weight of about 100-120 kg for the same overall dimensions.

Fig. 18 shows one way in which a connecting device 70 may be secured to the rest of a facing element. The facing element has a rear wall 41, as in the embodiment shown in Fig. 15, but the securing method could also be used in other embodiments. The rear wall 41 (or other portion of the facing element) is moulded with a recess 71 and immediately after unmoulding a bar 72, such as a 20mm diameter reinforcing bar, is placed to extend laterally in the recess in abutment with forward facing surfaces 73 of the recess 71. The bar 72 passes through a loop in an attachment lug 15 arranged to project from the rear of the element. The recess is filled with moulding material, e.g. concrete, so that the bar and the forward portion of the lug 15 are embedded, whereby the connecting device is secured to the rest of the element.The lug 15 is attachable to a reinforcement 30, or alternatively the reinforcement may itself have a loop through which the bar 72 extends, obviating the need for a separate lug. The shape of the recess 71 and the rest of the facing element is such that it can be removed from a mould immediately after the mould has been filled with e.g. concrete.

Fig. 19 shows the unmoulding step during the manufacture of the first embodiment of facing element, i.e. that of Figs. 1-5. A mould 80 is first filled with concrete via an open top thereof and the concrete is then vibrated and compacted. A connecting device (not shown in Fig. 19) is embedded in the concrete near the top of the mould so as to project upwardly from the concrete. A lid (not shown) is secured to the mould, the lid being of simple planar form and having an opening through which the connecting device projects.

The mould is turned upside down on to a sloping board 81 and is released from the lid, which rests on the board.

The mould is lifted vertically upwards by suitable means such as a crane to leave the facing element to harden while the mould is available for re-use. The whole process from starting to fill the mould through to removal of the mould ready for re-use takes a few minutes, so that the facing elements are easy and economical to manufacture. One mould may be used to produce 40 or 50 facing elements per day.

It will be appreciated from Figs. 4 and 7, for example, that at least the central upper surface 13 of the earth support member 2 is at an angle to the rear surface of the member which is less than 90", so that when the element is positioned with its rear surface arranged vertically, the upper surface slopes to the rear and assists in retaining earth on the support member. During manufacture, however, if the mould were received on a horizontal surface ready for unmoulding, the upper surface of the support member 2 would be reentrant to a vertical unmoulding direction of the mould.

This problem is overcome by positioning the mould on a mould receiving surface which slopes to compensate for the slope of the upper surface, so that it is possible to effect unmoulding by vertical lifting of the mould.

Thus in the preferred embodiment of Fig. 19, the sloping board 81 is used.

All the moulded surfaces of the facing element are in fact such that the mould can be simply lifted away from the mould receiving surface. In other words, none of the moulded surfaces are re-entrant to the direction of mould removal. This applies also to any recess formed by the mould for subsequent location of a connecting device. It will be noted therefore that the recess 71 shown in Fig. 18 would normally be formed by a mould which is removable in the forward direction of the facing element (a forward removal direction being shown in Fig. 19). A facing element such as that shown in Fig. 15 would however require mould removal in the upward direction of the facing element, and it would then be necessary to provide a recess having no surfaces re-entrant to this direction. To achieve this1 the recess 71 of Fig. 18 might be modified such that the forward facing surfaces 73 were vertical or sloping to the rear in the upward direction.

Whilst emphasis has been given to certain broad aspects in this specification, modifications may be made outside of the scope of such aspects whilst still providing at least some of the advantages of the constructions described herein. Attention is particularly directed to the feature that the earth support member of the facing element extends forwardly of the bearing portions of the laterally spaced posts, and the feature that the posts extend upwardly of the earth support member. These features and others disclosed herein may be of independent patentable significance.

Claims (17)

Claims

1. A facing element for a stabilised earth structure, comprising a connecting device for connection to a stabilising element, a support member for supporting earth and a pair of laterally spaced bearing members to support or partly to support a further facing element thereabove, the support arrangement of the bearing members being such that during construction of the structure relative forward and rearward, rotational and lateral positional adjustment is permitted between the facing element and the further facing element thereabove.

2. A facing element as claimed in claim 1, wherein the earth support member and the bearing members are integrally moulded in one piece.

3. A facing element as claimed in claim 2, wherein the shape of the facing element is such as to permit removal from a mould by inversion thereof on to a receiving surface and lifting of the mould.

4. A facing element as claimed in claim 1, 2 or 3, wherein the bearing members each have an upper bearing surface for supporting the facing element above, the upper bearing surfaces being located substantially in only the rear half of the facing element and the earth support member extending forwardly of the upper bearing surfaces.

5. A facing element as claimed in any preceding claim, comprising a rear wall extending below the earth support member to define a downwardly projecting fin which prevents forward passage of backfill.

6. A facing element as claimed in claim 5, wherein the fin is provided with a central forwardly extending web which allows the element to stand freely or with the aid of a wedge.

7. A facing element as claimed in any preceding claim, comprising a rear beam member extending laterally between the bearing members, upwardly spaced from the earth support member.

8. A facing element as claimed in any preceding claim, wherein the earth support member has side walls to restrain earth on the member from lateral displacement.

9. A facing element as claimed in any of claims 1 to 4, wherein the earth support member has no side walls and has side edges which, in use, are to be positioned adjacent to the side edges of adjacent facing elements.

10. A facing system for a stabilised earth structure, comprising a plurality of superimposed rows of facing elements as claimed in any preceding claim.

11. A facing system as claimed in claim 10, having a curve in plan view and a rearward batter, in which substantially all the facing elements have the same lateral dimension and are at different lateral spacings depending on their vertical position in the system.

12. A method of moulding a facing element for a stabilised earth structure, the facing element comprising a support member for supporting earth and a pair of laterally spaced bearing members to support or partly to support a further facing element thereabove, the method comprising placing moulding material in a mould to form the support member and the bearing members, locating in said moulding material a connecting device for connection to a stabilising element or locating in said moulding material a recess for receiving such a connecting device, and removing the moulding material from the mould by inversion thereof on to a receiving surface and lifting of the mould.

13. A method as claimed in claim 12, wherein the connecting device is embedded in the moulding material and projects therefrom.

14. A method as claimed in claim 12, wherein the mould includes a portion for forming the recess for the connecting device.

15. A facing element substantially as hereinbefore described with reference to the accompanying drawings.

16. A facing system substantially as hereinbefore described with reference to the accompanying drawings.

17. A method of moulding a facing element substantially as hereinbefore described with reference to the accompanying drawings.