GEOCOMPOSITE AND METHOD FOR THE PRODUCTION THEREOF

Abstract

A geocomposite which is suitable for the consolidation and/or drainage of ground, having a plurality of layers including at least a first web of geotextile and at least a second web of geotextile which are thermofixed to the sides of an intermediate separation layer which is produced by at least one geomat of entangled plastics threads having a thickness of approximately from 4 to 5 mm, or more. This geocomposite may be used as a basis in order to form a complex geocomposite, in which there is thermofixed to at least one of the webs of the basic geocomposite at least one additional layer of a geosynthetic selected from the group including geogrids, geonets, geomats, geotextiles, geomembranes or a combination or stratification thereof.

Claims

1. A geocomposite which is suitable for the consolidation and/or drainage of ground, composed of a plurality of layers comprising at least a first web of geotextile material and at least a second web of geotextile material which are thermofixed to respective sides of an intermediate separation layer which is produced by means of at least one geomat of entangled plastics threads having a thickness of approximately from 4 to 5 mm, or more, in order to form a basic geocomposite, in which there is thermofixed to at least one of the first web and the second web of the basic geocomposite at least one additional layer of a geosynthetic selected from the group comprising geogrids, geonets, geomats, geotextiles, geomembranes or a combination or stratification thereof.

2. The geocomposite according to claim 1, wherein at least one of the first and second geotextile webs is a water-repellent non-woven textile.

3. The geocomposite according to claim 1, wherein the at least one additional layer comprises at least one layer which is produced by means of a geogrid and/or a geomat which is/are thermofixed to one of the two geotextile webs of the basic geocomposite.

4. The geocomposite according to claim 1, wherein the at least one additional layer comprises at least one geomat which is reinforced by a geogrid, in which the plastics filaments of the geomat are entangled with the geogrid, the geomat which is reinforced by the geogrid being thermofixed to one of the two geotextile webs of the basic geocomposite.

5. The geocomposite according to claim 1, wherein the at least one additional layer comprises at least one geomat which is thermofixed to one of the two geotextile webs, an external web being thermofixed to the geomat, at the side opposite the one of the two geotextile webs.

6. The geocomposite according to claim 5, wherein the external web is a geomembrane.

7. A method for preparing a geocomposite according to claim 1, comprising the step of producing a basic geocomposite on the basis of a geomat of entangled plastics threads which are obtained by means of hot extrusion, the geomat having a thickness of approximately from 4 to 5 mm, or more, and being subsequently thermowelded at the sides thereof to two geotextile webs by means of localized heating.

8. The method for preparing a geocomposite according to claim 7, comprising the step of supplying the basic geocomposite to a thermowelding station in order to fix to at least one of the webs of the basic geocomposite one or more layer(s) of a geosynthetic which is selected from the group comprising geogrids, geonets, geomats, geotextiles, geomembranes or a combination or stratification thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other advantages and characteristics will become clear from the following detailed description of a preferred embodiment which is given with reference to the appended drawings which are provided purely by way of non-limiting example and in which:

[0017] FIG. 1 is a schematic perspective view of an example of the basic geocomposite, incorporating aspects of the present invention,

[0018] FIG. 2 is a schematic view of a plant for producing the basic geocomposite of FIG. 1,

[0019] FIG. 3 is a schematic, perspective view of a first example of a multi-layered geocomposite on the basis of the basic geocomposite of FIG. 1,

[0020] FIG. 4 is a schematic view of a plant for producing the multi-layered geocomposite of FIG. 3,

[0021] FIG. 5 is a schematic perspective view of a second example of the multi-layered geocomposite on the basis of the basic geocomposite of FIG. 1, and

[0022] FIG. 6 is a schematic view of a plant for producing the multi-layered geocomposite of FIG. 5.

DETAILED DESCRIPTION

[0023] With reference now to FIG. 1, a basic geocomposite 10 comprises a lower web 12 of a geotextile, preferably but in a non-limiting manner a non-woven textile, for example, of polypropylene. The basic geocomposite 10 further comprises an upper web 14 of a geotextile which is preferably but in a non-limiting manner a non-woven textile, for example, of polypropylene. The lower web 12 and the upper web 14 may be identical to or different from each other. In particular, for applications in which it is advantageous or necessary to produce a protection from ice, the lower web 12 may be of the water-repellent type, in particular with a dimension of the pores which is sufficiently small and such as to prevent moisture from passing through the lower web 12 via capillarity. The lower web 12 and the upper web 14 are fixed to the two sides of an intermediate separation layer 16 which is preferably produced with a geomat. As known in the sector, a geomat is a layer of material which is formed with entangled filaments of plastics material which are welded to each other so as to produce a structure having a given thickness and having a very low density and irregular voids therein. Preferably, the intermediate separation layer 16 has a thickness of approximately from 4 to 5 mm or more so as to prevent any contact, even accidental, between the lower web 12 and the upper web 14 following, for example, a localized pressure or crushing of the basic geocomposite 10 while being put into operation.

[0024] The basic geocomposite 10 is produced in a plant and according to a method of the generally known type, as schematically shown in FIG. 2. There are emitted from an extruder 21 hot filaments 23 of a plastics material, for example, polypropylene, polyethylene polyamide, polyester or an admixture of those polymers, and where applicable with a portion which also has a natural base. There is positioned below the extruder 21 a cooling tank 22 which contains a cooling liquid for cooling the hot filaments 23 which, by being supported on the roller 24, are intertwined with each other, forming a three-dimensional material structure. The extrusion speed of the hot filaments 23 and the speed of the roller 24 are adjusted and synchronized in order to obtain a geomat 16 having a predetermined thickness, preferably approximately from 4 to 5 mm or more. The geomat 16 is then caused to pass through a pair of rollers, a lower roller 29 and an upper roller 31, which preferably compress it slightly. One of the two webs which form the basic geocomposite 10 slides on the upper roller 31, for example, the upper web 14, which is supplied from a first coil 26. The other of the two webs slides on the lower roller 29, for example, the lower web 12, which is supplied from a second coil 27. In the passage between the lower roller 29 and the upper roller 31, the geomat 16 and the lower web 12 and upper web 14 are heated locally so as to become thermowelded. The localized heating may be carried out by heating the same lower roller 29 and upper roller 31 or by separate heating means, such as torches 30 or radiators or other functionally similar means.

[0025] In a variant which is not illustrated, the upper web 12 and lower web 14 are caused to pass both on the lower roller 29 and upper roller 31, respectively, while the roller 24 provides for the formation of the single geomat which will form the separation material 16 of the basic geocomposite 10. The basic geocomposite 10 described above may be advantageously used for producing multi-layered geocomposites. For this purpose, the basic geocomposite 10 may be conveyed to subsequent processing steps both online and offline. In the first case, there are provided downstream of the production plant for the basic geocomposite 10 additional processing stations which are synchronized with the production station of the basic geocomposite 10. Alternatively, the basic geocomposite 10 is stored after being, for example, coiled in basic coils 32, as schematically indicated in FIG. 2, which can be subsequently used for producing multi-layered geocomposites.

[0026] This last mode of use allows a substantial flexibility of use, being able to manufacture the basic geocomposite 10 both for use only as a conventional drainage geocomposite and for use as a basic material for producing more complex geocomposites which are suitable from time to time for specific requirements, in the quantities required at the time.

[0027] With reference now to FIG. 3, a first example of a complex geocomposite 20 comprises the basic geocomposite 10 which is constituted by two geotextile webs 12, a lower web 12 and upper web 14, which are welded to the intermediate separation layer 16 which is produced, for example, with a geomat, as indicated above, preferably having a thickness of from 4 to 5 mm or more. There is arranged, in a thermowelded state, on the upper web 14, at the side opposite the intermediate separation layer 16, a second intermediate separation layer which is also produced, for example, with a geomat, preferably also having a thickness of from 4 to 5 mm or more. There is arranged, in a thermowelded state, on the second intermediate separation layer 19 an external web 25 of a geotextile, which is preferably but in a non-limiting manner a non-woven textile, for example, of polypropylene or one of the materials set out above with reference to the lower web 12 and upper web 14. The external web 25 may be of the type which is identical to the lower web 12 and/or the upper web 14, or of the type which is different from both the lower web 12 and upper web 14. According to a particular embodiment, the external web 25 may also be an impermeable or water-repellent geosynthetic.

[0028] The multi-layered geocomposite 20 described above and illustrated by way of example in FIG. 3 may be produced in a plant and according to a method which are schematically indicated in FIG. 4. The plant has similarities to the one schematically described in FIG. 2 for producing the basic geocomposite 10. There are emitted from an extruder 21 hot filaments 23 of a plastics material, for example, polypropylene, polyethylene polyamide, polyester or an admixture of those polymers, and where applicable with a portion which also has a natural base. There is positioned under the extruder 21 a cooling tank 22 which contains a cooling liquid for cooling the hot filaments 23 which, by being supported on the roller 24, are intertwined with each other, forming a three-dimensional material structure. The extrusion speed of the hot filaments 23 and the speed of the roller 24 are adjusted and synchronized in order to obtain a separation geomat 19 having a predetermined thickness, preferably approximately from 4 to 5 mm or more. The separation geomat 19 is then caused to pass through a pair of two rollers, a lower roller 29 and an upper roller 31, which preferably compress it slightly. The basic geocomposite 10 which is unwound from the basic coil 32 passes over the lower roller 29.

[0029] The geotextile 25 which is unwound from a respective coil 26 is caused to pass over the upper roller 31.

[0030] During the passage between the lower roller 29 and upper roller 31, the basic geocomposite 10 is welded to the separation geomat 19 and connected to the external web 25 in order to form the multi-layered geocomposite 20 which is wound on a collection coil 35. The geomat 19 and the basic geocomposite 10 are heated locally so as to thermoweld them. The localized heating may be carried out by heating the same lower roller 29 and upper roller 31 or by separate heating means, such as torches 30 or radiators or other functionally similar means.

[0031] With reference now to FIG. 5, a second example of a complex geocomposite 40 comprises the basic geocomposite 10 which is described above and which is constituted by two geotextile webs 12, a lower web 12 and upper web 14, which are welded to the intermediate separation layer 16 which is produced, for example, with a geomat, as indicated above, preferably having a thickness of from 4 to 5 mm or more. At the side opposite the intermediate separation layer 16, there is fixed to the upper web 14 a geomat 42 which is reinforced with a geogrid 44, for example, of the type constituted by bands of plastics filaments which are thermowelded to each other in the manner of a warp and weft as indicated above with reference to the complex geocomposite 20 of FIG. 3. The geogrid 44 is mixed and/or interposed with entangled plastics filaments which form the geomat 42 during the extrusion process.

[0032] The multi-layered geocomposite 40 described above and illustrated by way of example in FIG. 5 may be produced in a plant and according to a method schematically illustrated in FIG. 6.

[0033] There are emitted from an extruder 21 hot filaments 23 of a plastics material, for example, polypropylene, polyethylene polyamide, polyester or an admixture of those polymers, and where applicable with a portion which also has a natural base. There is positioned below the extruder 21 a cooling tank 22 which contains a cooling liquid for cooling the hot filaments 23 which, by being supported on the roller 24, are intertwined with each other, forming a three-dimensional material structure. There is further caused to pass over the roller 24 the geogrid 44 which is unwound from a coil 26 and which passes over a tensioner 28, the recording position of which influences the position of the geogrid 44 which is more or less centred with respect to the centre of the geomat 42 which is formed by the filaments 23 which are welded to each other and also to the geogrid 44. The extrusion speed of the hot filaments 23 and the speed of the roller 24 are adjusted and synchronized in order to obtain a separation geomat 42 having a predetermined thickness, preferably approximately from 4 to 5 mm or more. The separation geomat 42 which is reinforced by the geogrid 44 is then caused to pass through a pair of two rollers, a lower roller 29 and an upper roller 31 in order to be connected to the basic geocomposite 10 in a manner similar to that described above with reference to FIG. 4, to which reference may be made.

[0034] Naturally, there may be provided other variants of complex geocomposites on the basis of the basic geocomposite 10, using any combination of one or more geogrids, geonets, geomats, geotextiles and/or geomembranes which are stratified at one of the two sides or at both sides of the basic geocomposite 10, according to production principles which will be evident to the person skilled in the art of the sector upon reading the present description and from the appended Figures. The intermediate separation layer 16 may also comprise one or more geonets or geogrids of material and/or one or more metal reinforcement nets which is/are fixed or interposed or interwoven with/to the entangled plastics filaments which compose the geomat of the intermediate separation layer 16.

[0035] Naturally, the principle of the invention remaining the same, the forms of embodiment and details of construction may be varied widely with respect to those described and illustrated without thereby departing from the scope of the present invention.