GB2239477A

GB2239477A - Facing system for earth structures

Info

Publication number: GB2239477A
Application number: GB9027468A
Authority: GB
Inventors: Yutaka Hirano
Original assignee: Societe Civile des Brevets Henri Vidal
Current assignee: Societe Civile des Brevets Henri Vidal
Priority date: 1989-12-29
Filing date: 1990-12-19
Publication date: 1991-07-03
Also published as: IT9048625A1; GB8929298D0; IT9048625A0; JP2663051B2; CA2033288A1; IT1241564B; GB9027468D0; FR2656639A1; JPH05331858A

Abstract

A facing system for a frictionally stabilised earth structure, comprising an assembly of facing panels (1) having means (8) for attachment to frictional stabilising members (9) embedded in the earth of said structure, the facing panels having side edge portions for connection to laterally adjacent facing panels, each such side edge portion having a lateral projection (3) and a lateral recess (4) respectively engaged with a lateral recess and a lateral projection of the adjacent facing panel, at least some laterally adjacent facing panels being assembled in the same plane as each other and at least some laterally adjacent facing panels being assembled at an angle to each other, the assembly of the facing panels in both cases being substantially sealed against passage of earth between adjacent panels. <IMAGE>

Description

FACING SYSTEM The present invention relates to a facing system for a frictionally stabilised earth structure.

British Patent No. 1069361 of Henri Vidal describes earth structures wherein stability is achieved by compacting successive layers of earth into frictional contact with stabilising members. These members stabilise the mass virtually completely by frictional forces, both between the reinforcements and the adjacent fill particles and between those particles and the remainder of the fill. The stabilising members are so spaced that the frictional forces are transmitted throughout the fill and tension generated in the stabilising elements opposes significant horizontal movement of the fill particles. A preferred type of reinforcement in these structures is an elongate flat steel strip which in use lies in the fill with its flat faces horizontal and with one end attached to a facing panel.

This earth stabilisation technique enables the structure to have at least one substantially vertical face and such a face will normally be clad with a facing system which, in order to conform to small movements created by the above compacting procedure and to accommodate the small elastic or even permanent movements of the structure permitted by the stabilisation technique, is preferably flexible in the plane of the face. In general, such flexibility can be provided by facing panels attached to the stabilising members. British Patent No. 1324686 discloses such a facing system in which the facing panels have interlocking side edge portions arranged to permit relative displacement between adjacent panels whilst preventing earth particles from passing between adjacent panels.With this known interlocking arrangement the facing panels must all lie in the same place since it is not possible to connect adjacent panels at an angle to each other.

It has been proposed in European Patent Application No. 0 345 077 (not published as of the priority date of this application) to form a facing which is angled or curved when viewed in plan. This is achieved by slightly turning a facing element relative to an adjacent element, but the design of the elements is such that the maximum amount of "turn" as between any two elements is limited to a few degrees. It is not therefore possible to achieve for example a right angle bend in the facing.

Viewed from one aspect the invention provides a facing system for a frictionally stabilised earth structure, comprising an assembly of facing panels having means for attachment to frictional stabilising members embedded in the earth of said structure, the facing panels having side edge portions for connection to laterally adjacent facing panels, each such side edge portion having a lateral projection and a lateral recess respectively engaged with a lateral recess and a lateral projection of the adjacent facing panel, at least some laterally adjacent facing panels being assembled in the same plane as each other and at least some laterally adjacent facing panels being assembled at an angle to each other, the assembly of the facing panels in both cases being substantially sealed against passage of earth between adjacent panels.

Viewed from another aspect the invention provides a kit of facing panels for assembly with each other to form a facing of a frictionally stabilised earth structure, each facing panel having means for attachment to at least one frictional stabilising member embedded in the earth of said structure, and a side edge portion for connection to a laterally adjacent facing panel, each such side edge portion having a lateral projection and a lateral recess respectively for engagement with a lateral recess and a lateral projection of the adjacent facing panel, the side edge portions being configured such that adjacent facing panels are engagable either in the same plane as each other, or at an angle to each other, the engagement in both cases being substantially sealed against passage of earth between adjacent panels.

The invention also provides a frictionally stabilised earth structure having such a facing system, and frictional stabilising members attached to said facing system and embedded in the earth of said structure.

Using facing panels in accordance with the invention it is possible to form a facing having therein one or more right angle or other angle bends, as viewed in plan, whilst the facing panel design also permits the more conventional arrangement in which adjacent panels lie in the same plane. Since the side edge portions of the facing panels are configured such that laterally adjacent facing panels may be connected to each other at any desired angle between the coplanar and at least a perpendicular arrangement, the facing may be designed to follow many possible profiles in plan view. The increased versatility of the facing panels thus provides greater choice to a designer of frictionally stabilised earth structures.

The side edge portions of the facing panels are preferably configured such that adjacent panels are engagable with each other with their rear faces turned towards each other with an angle of less than 1800 (e.g.

a right angle) therebetween, or with their front faces turned towards each other with an angle of less than 180 (e.g. a right angle) therebetween. Such an arrangement means that a facing can be bent in both directions as desired, producing either "external" or "internal" corners.

A facing will normally comprise a series of superimposed rows of facing panels, and it is possible for the panels of one row to follow a profile in plan view which differs from the profile of the row below.

Thus in a preferred form of the invention, the facing comprises a plurality of superimposed rows of facing panels, wherein a lower row includes two laterally adjacent facing panels arranged with their rear faces turned towards each other with an angle of less than 180 (e.g. a right angle) therebetween, and a row superimposed on said lower row includes two laterally adjacent facing panels arranged with their front faces turned towards each other with an angle of less than 180 (e.g. a right angle) therebetween, whereby an exposed area of earth is defined generally rearwardly of said two facing panels of the lower row and generally forwardly of said two facing panels of the superimposed row. Such an arrangement advantageously provides planting areas for vegetation whilst using relatively simple plate- or slab- like facing panels.

There are many possibilities for the plan view profile of each row of facing panels, providing the panels of a superimposed row are located either directly above or rearwardly of panels in the row below. Thus the size of an exposed area of earth may be limited to a rhombus or a square having sides all approximately equal to the lateral dimension of the panels, or the exposed area may take a variety of parallelogrammatic or rectangular shapes with dimensions approximating to multiples of the lateral dimensions of the panels. More complicated shapes are possible in view of the ability of a facing panel to be "bent" either forwardly or rearwardly relative to an adjacent panel.

With the arrangement described above, there will be some facing panels with a forward side edge portion supported by an adjacent facing panel and a rear side edge portion supported by the earth backfill below.

Where larger exposed areas of earth are provided, both side edge portions of certain facing panels may be supported on the backfill. It may then be desired to provide the facing panels with foundation pads to spread their weight on the backfill.

The earth backfill behind the facing panels will normally be compacted to ensure good frictional contact with the frictional stabilising members. It may not be easy to establish plant growth on compacted backfill and it may be desired to place topsoil on the backfill.

Alternatively, a hole of e.g. 35cm diameter may be drilled in the backfill to receive the roots of a shrub, tree or other plant or plants, with suitable soil being provided around the roots.

In order to maintain a seal between the side edge portions of the facing panels in the different possible positions thereof, preferably the side face of each lateral projection is formed as a convex curve, and the side face of the lateral recess of the adjacent facing panel with which said projection engages is formed as a complementary concave curve. This enables the gap between the connected side edges of the panels to be kept to a minimum whatever the angle between the panels to prevent escape of earth particles. Best results will generally be achieved if the convex and concave curves are part-circular, although a certain amount of deviation from part-circular curves will normally be permitted.

To ensure that adjacent facing panels are positioned correctly relative to each other, the panels are preferably provided with means for vertically aligning the engaged side edge portions. In a preferred embodiment the alignment means comprises a vertical hole formed in the lateral projection of each side edge portion, and a pin which in use is disposed in aligned vertical holes of adjacent panels. It is thus a relatively simple operation during construction to ensure that the side edge portions of adjacent panels are correctly aligned whilst at the same time adjustment of the angle between the panels can be easily achieved.

Where a panel has curved convex and concave side faces which are part-circular as discussed above, the centre of the curves will generally be at the vertical hole of the panel.

Various arrangements for the lateral projections and recesses of the facing panel side edge portions are possible. In a preferred embodiment the side edge portion has a lateral projection extending half the panel height and a lateral recess extending the other half of the panel height. Whilst it is possible for a facing panel to be formed at one side with the lateral projection on its lower half and at the other side with the lateral projection on its upper half, it is particularly preferred for the lateral projections on opposite sides of the facing panel to be provided at the same level as each other, and the lateral recesses similarly to be provided at the same level as each other. The panel is then generally "T" shaped. In a facing having a row of such facing panels, each facing panel will be inverted relative to the laterally adjacent panels.It will thus be appreciated that using a plurality of like facing panels a facing for a frictionally stabilised earth structure may be formed with considerable scope for variation of the profile of the facing.

In frictionally stabilised earth structures it is normally possible to use relatively lightweight facing panels since the earth pressures on the facing are not particularly high. In the present context, however, it is desirable for the lateral projections to be thicker than the main central region of the facing panel. This can provide increased strength and stability of the connection with adjacent panels, whilst at the same time saving on material by providing a relatively thin main central region.

The means for attaching the facing panels to at least one frictional stabilising member may for example comprise a lug projecting from the rear of the facing panel. In view of the ability of the facing panels to take up various positions relative tp the overall plane of the facing system, it is desirable for the stabilising member to be attached to-the lug by a single bolt, so that the orientation of the stabilising member is readily adjustable. Alternatively, where the angle between the facing panel and the stabilising member is known in advance, two or more bolts may be provided. In the case of relatively large panels, for example 1.5m wide by 1.5m high, a pair of lugs may be provided on each panel e.g. one vertically above the other in the centre of the panel.Alternatively, in a simplified arrangement the lugs may be omitted and a stabilising member may be attached to the vertical pin which connects the side edge portions of adjacent panels; this arrangement provides one stabilising member per panel and is thus suitable for smaller panels, for example l.0m wide by l.0m high. Even smaller panels might be provided, for example 0.25m wide by 0.25m high.

The facing panels may typically have a thickness of the order of 10 per cent of their height or width, so for example the larger 1.5m by 1.5m panels may have a thickness of 0.14m, 0.18m or 0.22m. A preferred embodiment of the facing panel having dimensions 1.5m by 1.5m by 0.18m has a weight of 1005 kg. A preferred embodiment of a smaller 1.0m by l.0m panel has a thickness of 0.075m and a weight of 430 kg. Where a central region thinner than the lateral projections is provided, the thickness of the lateral projections would generally be at least 0.15m greater than that of the central region.

Some preferred embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figures 1, 2 and 3 are respectively perspective, top plan and front elevation views of a facing panel'in accordance with the invention; Figure 4 is a rear perspective view of the facing panels assembled in a row; Figure 5 is a view similar to that of Figure 4 showing an alternative form of attachment of the stabilising members; Figure 6 is a front perspective view showing a structure having a facing assembled from the facing panels; and Figures 7, 8 and 9 are respective front elevation views of three embodiments of facing assembled from the facing panels.

Referring to Figures 1, 2 and 3, a facing panel 1, made for example of reinforced concrete, has a relatively thin central region 2 from which a pair of lateral projections 3 extend on opposite sides. The lateral projections each have a height equal to half the overall height of the panel and thus give the panel a generally "T" shaped appearance as seen in the elevation view of Figure 3. Vertically above each lateral projection 3 a lateral recess 4 is defined for receiving the lateral projection of an identical facing panel to be placed side-by-side the illustrated panel, inverted relative thereto (see Figures 4 and 5). Each lateral recess 4 also has a height half that of the overall panel height.

The thickness of the lateral projections 3 is greater than that of the central region 2 to give the connection with an adjacent panel improved strength and stability, particularly when the two connected panels are positioned at an angle to each other. Such an angle may be a right angle or any other angle less than 180 .

Each lateral projection 3 has a side face 5 formed with a convex curve, and the upper half of the central region 2 has opposed side faces 6 formed with a complementary concave curve. When two panels are placed side-by-side the convex and concave side faces 5 and 6 engage or are in close proximity with each other, both when the panels lie in the same plane or when they are arranged at an angle, so as to prevent escape of particles of earth backfill and to form a substantially continuous facing.

Each lateral projection 3 is formed with a vertical cylindrical hole 7 which might for example be lined with a metal or plastic sleeve (not shown). When assembling two panels side-by-side these holes 7 are aligned and a pin e.g. of metal is received therein to maintain the correct relative positions of the panels. Thus a pivotal axis is defined to enable one panel to be turned relative to the other from a coplanar arrangement to at least 900 either clockwise or anticlockwise.

Figure 4 shows part of a row of assembled facing panels 1 in a coplanar arrangement. Each of these panels is provided on its vertical centre line with a pair of vertically spaced lugs 8, formed for example of steel embedded in the concrete of the panel. Attached to each lug an earth stabilising member 9 in the form of a steel strip extends rearwardly into the earth backfill behind the facing panels. The strips are formed with transverse ribs on their lower and upper surfaces to improve their frictional grip with the earth.

Figure 5 shows an alternative means of attaching the stabilising members 9 to the facing panels 1. In this arrangement the members 9 are attached to the lateral projections 3 by means of a reinforcement bar (not shown) projecting from the concrete of the panel, for example a 16mm diameter bar. This results in the provision of one stabilising member per panel, thus being suitable for smaller sizes of panel. The reinforcement bar preferably also acts as the pin interconnecting adjacent panels, but alternatively the pin and the bar can be provided as separate members.

Figure 6 shows an earth structure having a facing assembled from the panels. The facing comprises a series of superimposed rows 10,11,12,13,14,15,16, with exposed earth planting areas 17 being provided at the upper level of each of rows 10 to 13, and a continuous facing being formed by rows 14 to 16. Referring to the lowermost row 10 a pair of laterally adjacent facing panels la, lb are connected with their rear faces turned towards each other and a right angle therebetween, an angle of 270 being defined between their front faces.

An external corner 18 is thus defined in the facing. A panel lc is arranged adjacent panel lb such that their front faces are turned towards each other with a right angle therebetween, an angle of 270 being defined between their rear faces. An internal corner 19 is thus defined in the facing.

In the superimposed row 11 a pair of facing panels ld,le form another such internal corner 20 above and rearwardly of the external corner 18 of row 10, so as to define a generally horizontal exposed earth area 17.

This arrangement is repeated elsewhere in the facing to produce earth planting areas at the upper levels of rows 10 to 13; once vegetation is established in these areas it can substantially enhance the appearance of the facing. The effect of this arrangement is also to cause the lower part of the facing to slope to the rear.

The upper rows 14,15,16 of the facing also include external and internal corners as described above but the panels are laid directly on top of each other so that the facing is continuous without planting areas.

Figures 7,8 and 9 show different ways in which rows of facing panels 1 may be superimposed on each other when all the panels are used in a substantially coplanar arrangement. In Figure 7 a panel placed directly on a panel below is inverted relative thereto. In Figure 8 a panel placed on a panel below is in the same orientation. The Figure 9 arrangement is similar except that the rows are laterally offset such that one side face 6 of a panel central region 2 is vertically aligned with a side face 5 of a panel lateral projection 3 in the tier below.

Claims

1. A facing system for a frictionally stabilised earth structure, comprising an assembly of facing panels having means for attachment to frictional stabilising members embedded in the earth of said structure, the facing panels having side edge portions for connection to laterally adjacent facing panels, each such side edge portion having a lateral projection and a lateral recess respectively engaged with a lateral recess and a lateral projection of the adjacent facing panel, at least some laterally adjacent facing panels being assembled in the same plane as each other and at least some laterally adjacent facing panels being assembled at an angle to each other, the assembly of the facing panels in both cases being substantially sealed against passage of earth between adjacent panels.

2. A facing system as claimed in claim 1, further comprising laterally adjacent facing panels arranged with their rear faces turned towards each other with an angle of less than 180 therebetween, and laterally adjacent facing panels arranged with their front faces turned towards each other with an angle of less than 180 therebetween.

3. A facing system as claimed in claim 1 or 2, comprising a series of superimposed rows of facing panels, wherein the facing panels of one row follow a profile in plan view which differs from the profile of the row below.

4. A facing system as claimed in claim 2, comprising a plurality of superimposed rows of facing panels, wherein a lower row includes two laterally adjacent facing panels arranged with their rear faces turned towards each other with an angle of less than 180" therebetween, and a row superimposed on said lower row includes two laterally adjacent facing panels arranged with their front faces turned towards each other with an angle of less than 180 therebetween, whereby an exposed area of earth is defined generally rearwardly of said two facing panels of the lower row and generally forwardly of said two facing panels of the superimposed row.

5. A facing system as claimed in any preceding claim, wherein the lateral projections of the facing panels have a side face formed as a convex curve, and the lateral recesses of the facing panels have a side face formed as a complementary concave curve.

6. A facing system as claimed in any preceding claim, including means for vertically aligning the side edge portions of laterally adjacent panels, the alignment means comprising a vertical hole formed in the lateral projections of the side edge portions of the adjacent panels, and a pin disposed in and aligning the vertical holes.

7. A facing system as claimed in any preceding claim, wherein the side edge portions of the facing panels have a lateral projection extending half the panel height and a lateral recess extending the other half of the panel height.

8. A facing system as claimed in any preceding claim, wherein the facing panels are generally "T" shaped.

9. A facing system as claimed in any preceding claim, wherein each facing panel has a main central region and lateral projections which are thicker than the main central region.

10. A frictionally stabilised earth structure having a facing system as claimed in any preceding claim, and frictional stabilising members attached to said facing system and embedded in the earth of said structure.

11. A kit of facing panels for assembly with each other to form a facing of a frictionally stabilised earth structure, each facing panel having means for attachment to at least one frictional stabilising member embedded in the earth of said structure, and a side edge portion for connection to a laterally adjacent facing panel, each such side edge portion having a lateral projection and a lateral recess respectively for engagement with a lateral recess and a lateral projection of the adjacent facing panel, the side edge portions being configured such that adjacent facing panels are engagable either in the same plane as each other, or at an angle to each other, the engagement in both cases being substantially sealed against passage of earth between adjacent panels.

12. A kit of facing panels as claimed in claim 11, wherein the side edge portions of the facing panels are configured such that adjacent panels are engagable with each other with their rear faces turned towards each other with an angle of less than 180 therebetween, or with their front faces turned towards each other with an angle of less than 180 therebetween.

13. A kit of facing panels as claimed in claim 11 or 12, wherein the lateral projections of the facing panels have a side face formed as a convex curve, and the lateral recesses of the facing panels have a side face formed as a complementary concave curve.

14. A kit of facing panels as claimed in claim 11, 12 or 13, including means for vertically aligning the side edge portions of laterally adjacent panels, the alignment means comprising a vertical hole formed in the lateral projections of the side edge portions of the adjacent panels, and a pin for location in the vertical holes to align them.

15. A kit of facing panels as claimed in any of claims 11 to 14, wherein the side edge portions of the facing panels have a lateral projection extending half the panel height and a lateral recess extending the other half of the panel height.

16. A kit of facing panels as claimed in any of claims 11 to 15, wherein the facing panels are generally "T" shaped.

17. A kit of facing panels as claimed in any of claims 11 to 16, wherein each facing panel has a main central region and lateral projections which are thicker than the main central region.

18. A facing system for a frictionally stabilised earth structure, substantially as hereinbefore described with reference to the accompanying drawings.

19. A frictionally stabilised earth structure having a facing system and frictional stabilising members attached to said facing system and embedded in the earth of said structure, substantially as hereinbefore described with reference to the accompanying drawings.

20. A kit of facing panels for assembly with each other to form a facing of a frictionally stabilised earth structure, substantially as hereinbefore described with reference to the accompanying drawings.