Abstract
A confinement structure comprises one or more open cells (70) for confinement, in use, of particulate fill materials such as soil, sand or aggregate. The cells (70) comprise walls (72) formed of a composite material comprising a polymeric grid layer laminated to a fabric layer. The walls (72) may be formed from a strip of the composite material comprising one or more living hinges. The cells (70) may be provided with skirt portions (74) that extend from at least some of the walls (72).
Claims
1. A confinement structure, comprising: a first open cell configured for confinement of particulate fill materials, the first open cell comprises (i) a first plurality of separate external wall panels each comprising a composite material defined by a polymeric grid layer thermally laminated to a fabric layer, and (ii) a first plurality of mechanical hinges each comprising a hinged piece of flexible fabric material; wherein the first plurality of separate external wall panels are pivotally connected using the first plurality of mechanical hinges; wherein the fabric layer of at least one external wall panel comprises bicomponent fibers having a sheath component and a core component, and wherein the sheath component is thermally bonded to the polymeric grid layer.
2. The confinement structure of claim 1, wherein the first plurality of mechanical hinges includes a first mechanical hinge bonded to a first polymeric grid layer of a first external wall panel and a second polymeric grid layer of a second external wall panel.
3. The confinement structure of claim 2, wherein the first mechanical hinge is adhesively glued or thermally bonded to the first polymeric grid layer and the second polymeric grid layer.
4. The confinement structure of claim 1, wherein the first plurality of mechanical hinges includes a first mechanical hinge bonded to a first fabric layer of a first external wall panel and a second fabric layer of a second external wall panel.
5. The confinement structure of claim 4, wherein the first mechanical hinge is adhesively glued, stitched, or thermally bonded to the first fabric layer and the second fabric layer.
6. The confinement structure of claim 1, wherein the first plurality of mechanical hinges comprise a geotextile material.
7. The confinement structure of claim 1, wherein the first plurality of mechanical hinges comprises a liquid impermeable fabric material.
8. The confinement structure of claim 1, wherein the composite material is vapor permeable.
9. The confinement structure of claim 1, wherein the fabric layer of at least one external wall panel comprises a microporous fabric material.
10. The confinement structure of claim 1, wherein the fabric layer of at least one external wall panel comprises a liquid impermeable and vapor permeable fabric.
11. The confinement structure of claim 1, further comprising a second open cell located adjacent to and interconnected with the first open cell.
12. The confinement structure of claim 11, wherein the second open cell comprises (i) a second plurality of separate external wall panels, and (ii) a second plurality of mechanical hinges; wherein the second plurality of separate external wall panels are pivotally connected using the second plurality of mechanical hinges.
13. The confinement structure of claim 12, wherein the first plurality of separate external wall panels includes a first external wall panel and the second plurality of separate external wall panels includes a second external wall panel; the first open cell and the second open cell being joined together to provide an inner wall defined by both of the first external wall of the first open cell and the second external wall of the second open cell.
14. The confinement structure of claim 11, wherein the first open cell, the second open cell, or both are provided with one or more skirt portions extending from at least one of the separate external wall panels.
15. The confinement structure of claim 14, wherein the one or more skirt portions are formed by a separate piece of material fastened to the composite material.
16. The confinement structure of claim 1, wherein the confinement structure comprises a first configuration comprising a flattened configuration wherein a first external wall panel and a second external wall panel are folded face-to-face against one another and a third external wall panel and a fourth external wall panel are folded face-to-face against one another.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Some preferred embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:
(2) FIG. 1 is a perspective view of a multi-cell confinement structure;
(3) FIG. 2a is a schematic drawing of a cell construction according to a first embodiment and FIG. 2b is an exploded view of a multi-cell unit confinement structure formed from such a cell;
(4) FIG. 3a is a schematic drawing of a cell construction according to a second embodiment and FIG. 3b is an exploded view of a multi-cell unit confinement structure formed from such a cell;
(5) FIG. 4a is a schematic drawing of a cell construction according to a third embodiment and FIG. 4b is an exploded view of a multi-cell unit confinement structure formed from such a cell;
(6) FIG. 5 shows additional hinge lines in the cell of FIGS. 3a and 3b;
(7) FIG. 6a is an exploded view of a first exemplary hinge construction and
(8) FIG. 6b shows the assembled hinge;
(9) FIG. 7a is an internal exploded view of a second exemplary hinge construction and FIG. 7b is an external exploded view of the hinge construction;
(10) FIG. 8 shows a first method of producing a living hinge;
(11) FIG. 9 shows a second method of producing a living hinge;
(12) FIG. 10 perspective view of a multi-cell confinement structure comprising skirt portions; and
(13) FIG. 11 shows the confinement structure of FIG. 10 with the skirt portions folded into the cells.
DETAILED DESCRIPTION
(14) There is seen in FIG. 1 a highly portable cellular confinement system 1 that when filled with a suitable aggregate or particulate fill can provide an effective asset protection structure for use in both the military and civil defence environments. The system is also likely to be well suited to flood defence applications.
(15) At least the external cell walls 2 of the confinement system are manufactured from a plastic composite material consisting of a polymeric grid or mesh layer and either one or two geotextile layers. The layers are laminated together. A suitable grid might be of the SS bi-axially orientated type such as that produced by Tensar International, Cunningham Court, Shadsworth Business Park, Blackburn, BB1 2QX, and a suitable net or mesh might be of the type produced by Fiberweb Geosynthetics, Maldon, Essex (previously Terram Limited). The polymeric grid or mesh might be manufactured with round, square, triangular or rhombus shaped openings but the preferred configurations would be square, rectangular or rhombus. The composite material is preferably manufactured by thermally bonding the polymeric grid or mesh layer to the geotextile layer(s) by means of a gas flame lamination process but a suitable adhesive lamination process could be used.
(16) The multi-cell unit 1 is made by gluing or stitching the required number of single cells together. The inner dividers or joining walls 4 might consist of a single geotextile layer with no reinforcement. It is shown in FIG. 1 that the corners of the cells comprise a hinge means 6, which may be provided by a separate hinged piece of material or by an integrally formed hinge. The cells of the unit 1 can therefore be collapsed and then zigzag folded.
(17) The cells can be assembled in a number of ways. Firstly, as seen in FIGS. 2a and 2b, cells can be formed from individual rectangular wall panels 8 joined by means of a fabricated hinge system. The hinges 10 provide the necessary flexibility to flat-pack the structure. FIG. 2a shows a single cell constructed from individual wall panels 8 joined at each corner by a fabricated flexible hinge 10the hinge material can be attached by gluing or sewing. FIG. 2b shows a multi-cell unit 11 formed by joining together three of the single cells. In such a unit the inner walls will be made of a double layer of the composite material of the wall panels.
(18) Alternatively, as seen in FIGS. 3 and 4, cells can be formed from strips of composite material. In these embodiments a strip of a length equivalent to the circumference of a single cell can be modified so as to contain a sufficient number of living hinges to allow the material to be folded to the desired shape and subsequently joined. For ease of formation of the living hinges, the composite material may be formed from a polymeric net layer that has not been aligned to provide tensile strength, such as a geonet or mesh from Fiberweb Geosynthetics (previously Terram Limited) rather than a biaxial geogrid or TriAx geogrid from Tensar.
(19) In FIG. 3a there is seen a cell formed from a strip 12 with three living hinges that create three of the corners and a single fabricated hinge 14 that creates the fourth corner. The hinge 14 may be provided by a separate piece of fabric material that connects the ends of the strip 12. FIG. 3b shows a multi-cell unit 21 formed by joining together three of the single cells. In such a unit the inner walls are again made of a double layer of the composite material. This embodiment requires less material than a cell construction that uses separate panels, as only one hinge piece is required. Moreover, manufacturing may be quicker and easier.
(20) In both embodiments described with respect to FIGS. 2 and 3, the fully-bonded construction of the composite material enables the textile layer to be utilized as a fully load bearing component in the construction of the hinge(s).
(21) In FIG. 4a there is seen a cell formed from a strip 16 with four living hinges that create all four of the corners of the cell so that no separate hinge pieces are required. A separate piece of material 18 may be used to connect the ends of the strip 16. A cell so formed may then be attached side-by-side with another cell to form a multi-cell unit. However, to save material and reduce assembly time the cells can be joined together in a multi-cell unit 31 as seen in FIG. 4b, with the cell wall adjacent the join between the ends of the strip 16 bridging the ends to make the connection without requiring the separate connecting piece 18 seen in FIG. 4a. A double layer is therefore formed at the inner walls of the structure, with the joining position in one wall being offset from that of an adjacent wall so that the strip forming each cell is fixedly connected by the strip forming the facing wall.
(22) FIG. 5 shows a single cell similar to that of FIG. 3a but with additional hinges 26 in two of the wall panels 22 which enable it to concertina fold. A multi-cell unit may consist of any practically transportable number of cells and more hinge assemblies might be incorporated into each cell to aid folding and thus improve the packing density of the product.
(23) There are a number of possible methods of manufacturing a hinge mechanism in cells formed of a composite or polymeric material.
(24) A first hinge construction is shown in FIGS. 6a and 6b for pivotal connection of two wall panels 32 formed of a composite material comprising a fabric layer 34 laminated to a polymeric grid layer 36. The hinge material 38 (e.g. a high strength geotextile fabric of a thermally bonded, mechanically bonded, or woven type) is attached to the composite wall panels 32, e.g. by means of a high strength adhesive or sewn, in such a manner that the hinged piece of material 38 always envelops at least one vertical member of the reinforcement grid in the polymeric layer 36. The gluing/stitching lines are highlighted in FIG. 6b. Incorporating the reinforcement grid layer 36 in the assembly of the hinge mechanism in this way ensures that any load applied to the cell walls 32 is fully absorbed by each component of the wall composite. The overlapping hinge piece 38 may also help to prevent delamination of the polymeric grid layer from the fabric layer 34.
(25) A second hinge construction requires that a three layered composite material is used to construct the cell walls 42, as is shown in FIGS. 7a and 7b. A polymeric grid layer 46 is laminated between a first fabric layer 44 and a second fabric layer 45. In this case a piece of hinge material 48 is attached by gluing or stitching to both the inner and outer fabric layers 44, 45 of the composite forming the wall panels 42. The result is a reinforced hinge and wall construction that ensures full integration with the stiff polymeric grid layer 46. This hinge construction also provides the flexibility of being able to fold the wall panels 32 either inwardly or outwardly.
(26) A third hinge construction does not use a separate hinge but instead requires that the composite material is pressed or deformed to cause localised extrusion of the polymeric grid material at the hinge pivot point, thus producing a form of living hinge. In FIG. 8 a high pressure (e.g. hardened steel) platen 50 acting against an anvil 58 is shown to form a living hinge in a panel 52 of composite material. In FIG. 9 a hardened steel wheel 60 is shown acting against an anvil 68 to form a living hinge in the panel 52 of composite material. The composite material of the panel 52 is seen to comprise a polymeric grid layer 56 sandwiched between a first fabric layer 54 and a second fabric layer 55, but the composite material may comprise a fabric layer on only one side of the reinforcement grid. The same technique may be used to form a living hinge in any polymeric material.
(27) To ensure total containment of the fill material and improve the stability of the structure during filling, each cell 70 may be fitted with a fabric skirt 74 as shown in FIGS. 10 and 11. The skirt 74 is manufactured from a lightweight geotextile fabric which is adhered or sewn to the inside lower edge of the external walls 72 of each cell compartment. Typically the fabric of the skirt 74 protrudes 100 to 150 mm below the edge of the cell wall 72 and can be folded into the cell prior to filling, as is seen from FIG. 11. In FIG. 11 the dotted lines show the containment skirts 74 folded into the cells 70 in the correct position for filling. The skirt 74 has the combined benefits of preventing the escape of fill material from underneath the cell walls 72 and the weight of fill material sitting on the skirt 74 can stop vertical displacement of the cell wall during the filling operation, thus aiding stability.
(28) Single and multiple units may be stacked to increase the height of a structure. In the case of the multi-cell unit seen in FIGS. 1 and 11 the internal dividers 4 are preferably 20 to 50 mm lower than the external walls 2, 72 to enable each layer to be nested into the preceding layer thus further reducing the risk of the escape of fill material and improving the overall stability of the structure by providing a degree of interlock.
(29) While the embodiments shown in the drawings have been described with respect to cell walls formed of a composite material, according to some aspects of the invention the cells may be formed from a rigid polymeric material, for example a strip of such material provided with living hinges.
