Multi-directional drainage geocomposite

Abstract

A multi-directional drainage geocomposite (1, 10, 11, 12, 13) comprises at least two drainage structures (2, 3) with a surface extent which is greater than the thickness and which are shaped so as to define respective main conveying directions (H-H; K-K) of a fluid flow along the extent thereof. The drainage structures (2, 3) are adjacent to each other, with respective surfaces facing each other. They are further connected to each other in a stable manner so that at least two respective main directions are orientated differently with respect to each other.

Description

[0001] MULTI-DIRECTIONAL DRAINAGE GEOCOMPOS ITE

[0002] Field of the invention

[0003] The present invention relates to the field of drainage geocomposites for geotechnical applications .

[0004] Technological background

[0005] Geocomposites are structures which are formed by a combination and / or superimposition of several elements , such as geotextiles , geogrids , geomats , geomembranes and the like , which are generally extensive in terms of width and particularly length, have a relatively small thickness and are used for various obj ects in civil engineering, for example , for reinforcement , separation, anti-erosion, stabili zation protection, sound-proofing and other similar applications in civil structures .

[0006] Among geocomposites there are known drainage geocomposites which are generally constituted by a draining core which may be a geomat , a net ( also called a geonet ) or a shaped element which is coupled at one side to a layer of geotextile or closed in a sandwich-like manner at the two sides thereof between two layers of geotextile . The drainage geocomposites are capable of performing filtration, separation and sometimes also other functions such as protection .

[0007] EP1160367 describes a geomat which is suitable for constructing the core of such a drainage geocomposite . This geomat is a structure with a high index of voids which is constructed with extruded plastics monofilaments which are intertwined with each other and which are shaped to confer on the geomat a "tip-like" profile .

[0008] An example of a drainage geocomposite is known under the commercial name "MACDRAIN® M" which is produced by Of ficine Maccaferri S . p .A. This drainage geocomposite is used in geotechnical applications in which it is necessary to drain water away, for example , rain water, by redirecting it away from its natural course in the ground . The properties of the geomat core confer on it high levels of planar drainage properties under medium / low loads . Typical even i f nonlimiting applications of such a geocomposite are drainage works , such as , for example , drainage works from planar to vertical and for consolidation by means of drainage , barrier systems for surfaces for capping landfill sites , applications of "roof gardens" in buildings .

[0009] In order to increase the characteristics of resistance to loads , it is known to construct a drainage geocomposite with drainage and filtration functions having a geomat core with monofilaments which is no longer shaped in a "tip-like" manner but instead shaped in a wave-like or W-shaped or zigzag manner, that is to say, shaped so as to define a series of mutually parallel channels with a sectional profile which is substantially similar . This geomat core is also coupled to one or two geotextile filters at one or both sides thereof . Such a geocomposite is known by the commercial name MACDRAIN® W which is also produced by Of ficine Maccaferri S . p .A. The wave-like shaping of the geomat which is brought about , for example , in accordance with the teachings of US 4252590 , confer on the geocomposite optimum properties of planar drainage with high flow rates of water even when it is subj ected to high overloads .

[0010] However, the geocomposite which uses such a shaped geomat with parallel channels has a preferential drainage direction for the water which limits the possibility of use when a multi-directional planar drainage is instead required, as instead obtained with a geocomposite , the core of which is constructed with the less resistant but multi-directional non-orientated geomat core .

[0011] Therefore , there is perceived in the field the need for a drainage geocomposite which at the same time has a good resistance to loads and is capable of providing a multidirectional drainage .

[0012] Statement of invention

[0013] An obj ect of the invention is therefore to solve the problems of the prior art and to provide a drainage geocomposite which demonstrates a good level of resistance to loads and which is capable of providing multi-directional drainage .

[0014] Another obj ect of the invention is to provide a geocomposite which is simple and economical to manufacture and which does not require particular arrangements for putting it into operation, other than those already known and used in the field of drainage geocomposites .

[0015] These obj ects and other obj ects are achieved by a geocomposite having the features indicated in the appended claims .

[0016] According to a first aspect , there is described a multidirectional drainage geocomposite which may comprise at least two drainage structures , for example , geomats which are formed by extruded filaments which have an open reticular structure or, still by way of example , thermoformed polymer structures . These drainage structures have thicknesses which are far less than the extent thereof in terms of width and length so as to each define two respective faces which extend in terms of width and length . The at least two drainage structures are shaped so as to each define a respective main conveying direction of a fluid flow, for example , but not only, water, along the extent thereof . In other words , the fluid flow which flows in each drainage structure flows along the extent thereof , mainly in the respective main conveying direction, for example , in terms of width or length, while the fluid flow is substantially smaller, i f not even absent , in the other directions and along the thickness of the drainage structure .

[0017] The at least two drainage structures with main directions are arranged adj acent to each other and connected to each other with two respective facing surfaces thereof in accordance with a configuration such that the main conveying directions of the two drainage structures are orientated di f ferently with respect to each other, that is to say, in such a manner that the two main conveying directions are not parallel with each other .

[0018] This drainage geocomposite therefore allows the liquid which runs through it to be drained away in accordance with at least two di f ferent directions , mainly or exclusively in accordance with the main directions of the two drainage structures , thereby obtaining a multi-directional drainage geocomposite , the compression strength of which is greater than the compression strength of a conventional multidirectional drainage geocomposite .

[0019] According to a particular aspect , at least one of the drainage structures with main directions , preferably two drainage structures beside each other, are geomats with an open reticular structure which are constructed preferably but in a non-limiting manner by means of extruded mono- filaments in accordance with techniques known in the field of production of geomats with parallel channels , for example , undulating or W-shaped or zig- zag geomats . The ready availability and practicality of manufacture of the geomats with a main direction, such as the geomats with a profile with parallel channels , makes it convenient and economical to produce a resistant multi-directional drainage geocomposite such as the one of the present invention .

[0020] According to a particular aspect , the drainage geocomposite may further comprise a first sheet which is connected, in contact , to one of the at least two drainage structures with main directions , in particular one of the geomats with parallel channels , so as to cover one side thereof . The sheet may be a filter sheet which can be passed through by the fluid when there is a suf ficient pressure di f ference between one side and the other of the sheet . In any case , it is not excluded that the filter sheet may act , completely or partially, in accordance with other principles , for example , by capillarity or osmosis .

[0021] According to an advantageous aspect , the above-mentioned first sheet may be an intermediate filter sheet which is interposed between the mutually facing sides of the first and second drainage structure with a main direction, for example , of the first and second geomats with parallel channels .

[0022] According to a particular aspect , the geocomposite may comprise at least one second sheet which covers at least one of the two drainage structures , preferably geomats , at the external side thereof , opposite the side facing the other drainage structure , preferably a geomat .

[0023] According to another particular aspect , the multi-directional drainage geocomposite may comprise at least a third sheet which also covers the other drainage structure with a main direction, at the external side thereof , so that the second and third sheets cover in a sandwich-like manner the drainage core which is composed by the assembly of the at least two drainage structures and the first sheet which is interposed between them .

[0024] According to another advantageous aspect , one , two or all of the sheets cited can be non-permeable with respect to water, thereby forming drainage compartments for the water which are impermeable with respect to each other, that is to say, such that the water is confined in the zone of the at least two geomats with parallel channels .

[0025] According to a particularly advantageous aspect , the multidirectional drainage geocomposite can be constructed with two drainage structures with a main direction, having the same thickness . In this manner, it is possible to use the same type of one-directional drainage structure , forming from it , in a state cut to si ze , both the drainage structures to be connected in the multi-directional drainage geocomposite . Otherwise , it is possible to construct the drainage geocomposite with drainage structures which have di f ferent characteristics , for example , with regard to the flow rate in the main direction, in this case obtaining a geocomposite which, notwithstanding that it is multi-directional , has a main flow conveying direction over the others .

[0026] According to another particularly advantageous aspect , the at least two drainage structures can be geomats formed by intertwined filaments , for example , made of plastics material , including recycled material , or natural material , which form a drainage matrix with a high index of voids , wherein the matrix of the geomat has a profile with parallel channels , in which peaks and valleys which define a succession of channels which define the main conveying direction alternate with each other . The channels can be closed, that is to say, with continuous walls which are formed by compact filaments , or can have an open reticular structure which partially allows , even i f not mainly, the fluid passage in a di f ferent direction from the main direction defined by the extent direction in terms of length of the parallel channels . These geomats are simple and economical to construct by means of apparatuses which are generally known in the field . For this reason, the geocomposite which results from the connection of these geomats is also economical , as well as being particularly resistant to compression .

[0027] According to a particular aspect , the main direction defined by the first drainage structure with a main direction is orientated at an angle greater than 0 ° and less than or equal to 90 ° with respect to the main direction defined by the second drainage structure . Even more advantageously, the angle between the first main direction and the second main direction is between 10 ° and 90 ° , preferably the angle is between 30 ° and 90 ° , more preferably it is between 45 ° and 90 ° , even more preferably it is between 60 ° and 90 ° , much more preferably the angle is between 80 ° and 85 ° . The arrangement which is most advantageous , particularly from the point of view of the ease of production, is the one in which the main directions of the two drainage structures are perpendicular to each other .

[0028] In the geocomposite , it is possible to construct the second sheet , that is to say, one of the external sheets with respect to the core which is formed by the drainage structures with main directions , as the geotextile filter sheet , both of the woven type and of the non-woven type , or as an impermeable sheet or also in the form of a film or with a geomembrane .

[0029] There is further described a method for manufacturing a drainage geocomposite , comprising the steps of :

[0030] - providing at least two drainage structures each having two dimensions with a greater extent with respect to a thickness thereof , and which are shaped so as to define two respective main conveying directions of a fluid flow in the extent plane of the geomats ,

[0031] - superimposing the two drainage structures one on the other, with two respective faces facing each other,

[0032] - connecting in a stable manner the two drainage structures with main directions to each other so that the respective main directions are orientated di f ferently from each other, that is to say, non-parallel with each other .

[0033] In the method, advantageously the two drainage structures can be connected to each other by interposing therebetween a first sheet which therefore acts as an intermediate sheet between the two drainage structures . The two drainage structures are preferably thermo-welded at opposite sides of the intermediate sheet . The whole can be supplemented by an external sheet which is fixed to one of the two drainage structures with a main direction or by two external sheets which close in a sandwich-like manner the drainage core which is formed by the drainage structures with the intermediate sheet ( s ) .

[0034] According to an alternative method for constructing the drainage geocomposite of the present invention, it is possible to provide a base drainage geocomposite having as a drainage core a geomat with an open reticular structure which defines a first main conveying direction, for example , a geomat of the type with parallel channels , also called a Ilshaped channel , zig- zag channel or the like . There is provision in this base drainage geocomposite for extruding a second geomat with an open reticular structure , wherein there is defined a second main conveying direction which is orientated di f ferently from the first main conveying direction of the geomat of the first drainage geocomposite , that is to say, so that the first and second main conveying directions are not parallel with each other .

[0035] In any case , the invention is not limited to the connection of only two drainage structures or geomats , nor does the type of sheets used limit the invention, wherein the drainage core formed by the geomats can be connected with various combinations of sheets and / or other geocomposites to be selected in accordance with the speci fic applications for which the multi-directional drainage geocomposite of the present invention is intended .

[0036] Brief description of the drawings

[0037] Additional features and advantages will become evident from the following detailed description of a preferred embodiment with reference to the appended drawings which are given merely by way of non-limiting example and in which :

[0038] - Figure 1 is a perspective , exploded view of a drainage geocomposite incorporating aspects of the present invention;

[0039] - Figure 2 is a perspective view of the drainage geocomposite of Figure 1 in the assembled configuration for use ;

[0040] - Figure 3 is a perspective view of a first variant of a drainage geocomposite according to the invention;

[0041] - Figure 4 is a perspective view of a second variant of a drainage geocomposite according to the invention;

[0042] - Figure 5 is a perspective view, similar to Figures 3 and 4 , of a third variant of a drainage geocomposite according to the invention; and

[0043] - Figure 6 is a perspective view of a fourth variant of a drainage geocomposite according to the invention .

[0044] Detailed description

[0045] In the following embodiments , there are described features which allow the invention to be carried out . The features described can be combined with each other in various manners and are not necessarily limited to the precise embodiment to which the drawings and the relevant description refer . In other words , a person skilled in the art in the sector who reads the following description will know how to obtain the information items which are useful for knowing the way to carry out one or more of the features described by combining it with one or more of the other features described without the particular formulation of the description, the paragraphs , phrases or drawings constituting a limitation on the possibility of isolating one or more of the features described and illustrated in order to combine them with one or more of any of the other features described and illustrated . The materials , forms and functions described and illustrated do not limit the present invention but are only speci fied in order to enable a person skilled in the art to understand and carry out the invention according to preferred but non-exclusive embodiments .

[0046] In the following description, reference will be made to the use of drainage structures in the form of geomats with parallel channels , but naturally the same considerations also apply to using drainage structures with channels with continuous walls , for example , but in a non-limiting manner, constructed with a thermo- formed, undulating polymer sheet so as to form unidirectional conveying channels for liquids , in particular water .

[0047] Now with reference to Figures 1 and 2 , a drainage geocomposite 1 incorporating features of the present invention comprises a first geomat 2 and a second geomat 3 which are adj acent . In the example of the Figures , the two geomats 2 , 3 are separated by a sheet 4 of filtering geotextile but in other embodiments , as will be seen below, the two geomats can be superimposed one on the other directly without any intermediate layer .

[0048] The geomats 2 , 3 , which are sometimes also called "permeable felts" , "veils" , "pads" or "mats" are formed by filaments of a thermoforming plastics material , for example , polypropylene , which are intertwined with each other so as to form loops or curls which are disordered and partially welded to each other at the intersection points . The filaments form a matrix with a high index of voids , that is to say, with a high ratio between the volume of voids and the volume occupied by the plastics material from which the filaments are formed . For the forming of the geomats , there are used synthetic polymers which are suitable for being spun in the molten state and which run from a die which has noz zles which are aligned and solidi fy in a cooling bath below, for example , a water bath . The filaments are welded to each other as a result of the adhesive nature of the material which is still in the softened state in order then to give rise to a sparse but solid geomat which is generally characteri zed by a resilient behaviour or, more preferably, visco-elastic behaviour during compression . The filaments being discharged from the die fall at least partially onto a roller which is substantially immersed in the cooling bath . The surface of the roller is shaped to confer an undulating configuration on the geomat when the filaments have solidi fied . In general terms , the geomats 2 , 3 have such a configuration as to define a main flow direction of a fluid flow indicated in Figures 1 and 2 , respectively, with the line H-H for the first geomat 2 and with the line K-K for the second geomat 3 . However, the configuration of the geomat 2 , 3 does not prevent the fluid from flowing, even though with a substantially lower flow, in other directions di f ferent from the main direction .

[0049] In the preferred embodiment , the geomats 2 , 3 have an undulating structure , also called a W-shape , which has an alternation of peaks 5 and valleys 6 which define parallel channels 7 which extend in terms of length parallel with the main flow direction H-H or K-K, respectively . The undulating form of the geomats 2 , 3 improves the compression resistance thereof with respect to a generally three-dimensional configuration which is accidental or with tips .

[0050] As illustrated in the Figures , the undulating form of the geomats 2 , 3 defines a group of channels 7 which are elongate in a preferential direction . As illustrated in Figure 2 , the main directions H-H and K-K are incident to each other and form an angle a which in the Figure which illustrates the preferred embodiment is 90 ° , that is to say that the main directions of the first and second geomats are perpendicular to each other .

[0051] However, the angle a between the two main directions may take up a smaller value , preferably up to a minimum of approximately 10 ° . Therefore , the first main direction H-H which is defined by the first geomat 2 can be orientated at an angle of from 10 ° to 90 ° with respect to the second main direction K-K which is defined by the second geomat 3 . More preferably, the angle a can be from 30° to 90°, even more preferably from 45° to 90°, much more preferably from 60° to 90°. The angle between the first main direction H-H and the second main direction K-K may also be similar, but less than 90°, for example, between 80° and 85°.

[0052] The sheet 4 which is interposed between the two geomats 2, 3 is preferably thermo-welded to both. In this manner, there is formed a good structural connection between the two geomats which will be welded to the sheet 4 in the region of the peaks 5 or the valleys 6 of the channels 7 which are positioned beside the two surfaces, the lower and upper surfaces in Figures 1 and 2, of the sheet 4, respectively.

[0053] Two additional external sheets 8, 9 can close in a sandwichlike manner the assembly of the two geomats 2, 3 and the sheet 4 which is interposed between them. The external sheets 8, 9 can also each be thermo-welded to a respective geomat 2, 3 in the region of the valleys 6 of the geomat 2 and the peaks 5 of the geomat 3, respectively, as illustrated in the Figures. Basically, each geomat 2, 3 is closed between two sheets, of which the intermediate sheet 4 is common to both the geomats 2, 3.

[0054] Each of the sheets, the intermediate sheet 4 and external sheets 8, 9, can be both a nonwoven and woven geotextile or can be in turn a geocomposite, in particular a geotextile which is connected to a film or also a geomembrane.

[0055] Naturally, the sheets 4, 8, 9 can also be fixed to the geomats with other systems, for example, of the mechanical type, using clips, bindings, stitches, through tie rods or other functionally similar systems. It is not excluded that under particular conditions it may be advantageous to use an adhesive .

[0056] As mentioned above , various variants of the geocomposite 1 are possible . Figure 3 illustrates a geocomposite 10 similar to the geocomposite 1 described above but without one of the two external sheets . Reference numerals which are the same in Figures 2 and 3 indicate identical components .

[0057] The geocomposite 10 of Figure 3 is composed by two geomats 2 , 3 with main directions angled relative to each other at 90 ° in the case illustrated, even i f it is possible to orientate the main directions in accordance with di f ferent angles , greater than 0 ° , in a generally similar manner to what is described above with reference to the geocomposite 1 . The two geomats 2 , 3 are separated from each other by the intermediate sheet 4 . One of the two geomats , in particular the geomat 3 illustrated in the upper region of Figure 3 , is covered externally by the sheet 9 . As can be seen, the geomat 2 , illustrated in the lower region of Figure 3 , is not covered externally by any sheet .

[0058] Figure 4 illustrates a geocomposite 11 similar to the geocomposite 1 described above but without both the two external sheets . Reference numerals which are the same in Figures 2 and 4 indicate identical components .

[0059] The geocomposite 11 of Figure 4 is composed of the two geomats 2 , 3 with main directions angled relative to each other at 90 ° in the case illustrated, even i f it is possible to orientate the main directions in accordance with di f ferent angles , greater than 0 ° , in a generally similar manner to what is described above with reference to the geocomposite 1 . The two geomats 2 , 3 are separated by the intermediate sheet 4 . As can be seen, none of the two geomats is covered externally by any sheet .

[0060] The geocomposites 10 , 11 in which one or both of the geomats do not have any covering at the side opposite the intermediate sheet 4 are highly suitable for any particular applications in which, for example , it is desirable to disperse a granular material inside the matrix formed by the interlaced filaments of the geomat ( s ) .

[0061] Figures 5 and 6 show another two embodiments of the geocomposite , both not having any intermediate sheet 4 .

[0062] More specifically, in Figure 5 the core of a geocomposite 12 is formed by the two geomats 2 , 3 which are positioned beside each other and fixed directly to each other, for example , by thermo-welding, which can be carried out with locali zed heating, for example , of the peaks 5 of the lower geomat 2 and / or the valleys 6 of the upper geomat 3 . Alternatively or additionally to the thermo-welding, the two geomats 2 , 3 can also be fixed to each other by other systems , for example , of the mechanical type , using clips , bindings , through tie rods or other functionally similar systems . It is not excluded that under particular conditions it may be advantageous to use an adhesive . The two geomats 2 , 3 are closed in a sandwich-like manner at the respective external sides thereof by two sheets 8 , 9 which are functionally and structurally similar to the ones already described with identical reference numerals in Figures 1 and 2 . Even in the case of the geocomposite 12 of Figure 5 , the geomats 2 , 3 also have the respective main directions orientated perpendicularly with respect to each other even i f - as explained above - this feature is preferred but non-limiting given that the angle between the two main directions may take up di f ferent values greater than 0 ° , up to 90 ° . Figure 6 illustrates a geocomposite 13 in which the two geomats 2 , 3 are positioned beside each other and fixed directly to each other, similarly to the ones of the example of Figure 4 . In this case , however, there is provided only one external sheet 9 which covers the geomat 3 while the external side of the geomat 2 is not covered, similarly to what has already been described with reference to the geomat 10 of Figure 3 .

[0063] In order to construct the drainage geocomposites described above , it is possible to proceed by providing the first geomat and the second geomat , which are normally provided in rolls , in an installation comprising two reels or other means which are suitable for progressively unrolling the two geomats . The two geomats are positioned in such a manner that they can cross each other, being positioned one on the other, together forming the generic angle a, preferably substantially equal to 90 ° , between the preferential directions H-H and K-K which, in the maj ority of cases , are parallel with the unrolling and advance direction of the geomats in the manufacturing installation of the geocomposite .

[0064] Alternatively, it is possible to provide two rolls of geomat in which the preferential directions are already orientated di f ferently in the geomat rolls . For example , one of the two geomats may be provided in a roll in which the preferential direction is parallel with the unrolling direction of the roll , while the other of the two geomats can be provided in a di f ferently prepared roll , wherein the preferential direction of the geomat is orthogonal to the unrolling direction of the roll . It is thereby possible to position the two rolls in the installation so as to unroll the two geomats , one positioned on the other, in parallel directions , thereby already being located with the two respective preferential directions orientated perpendicularly to each other .

[0065] I f the geocomposite provides for the intermediate sheet 4 , it can be fixed, preferably thermo-welded, to one of the two geomats before the other geomat is overlaid and thermo-welded on it . In an integrated process , it is possible to simultaneously j uxtapose the two geomats with the intermediate sheet positioned between them so as to thermoweld all three layers at the same time .

[0066] According to another methodology for producing the geocomposite of the present invention, it is possible to use a drainage geocomposite of the known type with a geomat with parallel channels which can form a drainage core with one or two sides covered by a respective geotextile . This drainage geocomposite is caused to pass into an apparatus for forming geomats in such a manner that , at one of the faces thereof , which is or is not provided with geotextile , a second geomat with parallel channels having a main direction di f ferent from that of the parallel channels of the first geomat is extruded, preferably but in a non-exclusive manner orientated at 90 ° with respect to each other . Using the same apparatus it is then possible to couple , at the external side of the second geomat j ust formed, the other potential geotextile i f it is desirable to construct a geocomposite in which the drainage core formed by the geomats is closed in a sandwichlike manner between the geotextile of the initial drainage geocomposite and the second geotextile which is applied in the apparatus after the second geomat is produced .

[0067] Naturally, the production processes described above can be modi fied in order to take account of the speci fic configuration of the geocomposite which it is desirable to obtain, in particular in accordance with the number of geomats and the number and position of the geotextiles used with respect to the geomats .

[0068] Therefore , it is possible , i f the geotextile provides for one or two external sheets , for them also to be thermo-welded or in any case fixed to the external sides of the drainage core comprising the geomats in accordance with known fixing techniques , for example, by thermo-welding .

[0069] There are possible variants with respect to the geocomposites of the present invention which a person skilled in the art will be able to readily identi fy having learnt the principles of the invention from the present description . For example , the number of geomats positioned one above the other may be greater than two . For example , it is possible to construct geocomposites which are formed by three geomats with axes staggered by 45 ° so as to define main fluid flow directions in two directions which are perpendicular to each other and a third bisector direction of the angle of 90 ° which is formed between the other two geomats . Naturally, there are also possible other combinations of orientation between the main directions of the various geomats so as to generally define the flow multi-direction of the fluid of the drainage geocomposite .

[0070] The thickness of the geomats which defines the depth of the channels as well as the width of the channels themselves , that is to say, the pitch between peaks and valleys , may be identical for the two or more geomats or may be di f ferent in order to supply to the geocomposite generally main behaviour in one or more directions , for example , where the fluid flow rate in the main direction of a geomat can be greater than the fluid flow rate in the main direction of another geomat which is positioned above it as a result of the di f ferent dimensions of the channels or in any case of the flow areas of the fluid in the two geomats .

[0071] 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 .

Claims

1. A multi-directional drainage geocomposite (1, 10, 11, 12, 13) comprising at least two drainage structures (2, 3) which have an extent which is greater than the respective thickness thereof and which are shaped so as to define respective main flow conveying directions (H-H; K-K) in order to convey a fluid flow along the extent thereof, the drainage structures (2, 3) being adjacent to each other, with respective surfaces facing each other, the drainage structures being connected to each other so that at least two respective main flow conveying directions are orientated differently with respect to each other.

2. A multi-directional drainage geocomposite according to claim 1, comprising at least a first sheet in contact with a surface of one (2) of the at least two drainage structures (2, 3) .

3. A multi-directional drainage geocomposite according to claim 2, wherein the first sheet is an intermediate filter sheet (4) which is interposed between the mutually facing surfaces of two drainage structures (2, 3) .

4. A multi-directional drainage geocomposite according to claim 2, comprising at least a second sheet (9) which covers at least one external surface of the drainage structures (2, 3) , opposite the surface which faces another drainage structure ( 3 , 2 ) .

5. A multi-directional drainage geocomposite according to claim 4, comprising at least a third sheet (8) which covers the external surface of the other drainage structure (3, 2) so as to close in a sandwich-like manner together with thesecond sheet (9) the assembly of the drainage structures (2, 3) with the intermediate sheet (4) being interposed.

6. A multi-directional drainage geocomposite according to any one of the preceding claims, wherein the thicknesses of the drainage structures (2, 3) are substantially identical to each other.

7. A multi-directional drainage geocomposite according to any one of the preceding claims, wherein the drainage structures are geomats having an open reticular structure and a configuration with parallel channels which define in each geomat the relative main flow conveying direction.

8. A multi-directional drainage geocomposite according to claim 7, wherein the geomats (2, 3) are formed by irregularly intertwined plastics filaments which are welded to each other at the contact points and which form a drainage matrix with a high index of voids, wherein the matrix of the geomat has an undulating profile, in which peaks (5) and valleys (6) which define the succession of parallel channels (7) which define the main flow conveying direction (H-H; K-K) alternate with each other.

9. A multi-directional drainage geocomposite according to any one of the preceding claims, wherein a first main flow conveying direction (H-H) defined by a first drainage structure (2) is orientated at an angle (a) greater than 0° and less than or equal to 90° with respect to a second main flow conveying direction (K-K) defined by a second drainage structure (3) .

10. A multi-directional drainage geocomposite according to claim 9, wherein the angle (a) between the first main flowconveying direction (H-H) and the second main flow conveying direction (K-K) is between 10° and 90°, preferably the angle is between 30° and 90°, more preferably it is between 45° and 90°, even more preferably it is between 60° and 90°, much more preferably the angle is between 80° and 85°.

11. A multi-directional drainage geocomposite according to claim 9, wherein the first main flow conveying direction (H- H) is substantially perpendicular to the second main flow conveying direction (K-K) .

12. A multi-directional drainage geocomposite according to claim 4 or claim 5, wherein the second sheet (9) is an impermeable sheet or a film or a geomembrane.

13. A method for manufacturing a multi-directional drainage geocomposite, comprising the steps of:- providing at least two drainage structures (2, 3) with a greater extent with respect to the thickness, which are shaped so as to define respective main flow conveying directions (H-H; K-K) in order to convey a fluid flow along the extent thereof,- arranging in an adjacent manner the at least two drainage structures (2, 3) with respective surfaces facing each other,- connecting the at least two drainage structures (2, 3) to each other so that at least two respective main flow conveying directions (H-H; K-K) are orientated differently from each other.

14. A method according to claim 13, further comprising the step of connecting at least one sheet in contact with a surface of one (2) of the at least two drainage structures (2, 3) .

15. A method for manufacturing a multi-directional drainage geocomposite, comprising the steps of: providing a drainage structure (2) comprising a first drainage geomat with parallel channels defining a first main flow conveying direction (H-H) ; extruding a second drainage geomat (3) with parallel channels on the first drainage structure (2) , defining a second main flow conveying direction (K-K) which is orientated differently from the first main flow conveying direction (H-H) .

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