REINFORCING NET STRUCTURE FOR GEOTECHNICAL APPLICATIONS, USE OF THE REINFORCING NET STRUCTURE, AND A METHOD FOR PRODUCTION OF THE REINFORCING NET STRUCTURE

- TENAX S.P.A.

A product for reinforcing terrain includes a net structure made of a plastic material having a plurality of bars and a plurality of elongate elements that are transversal with respect to the bars. The elongate elements are arranged between adjacent pairs of bars and exhibit a substantially wire-like structure, with a transversal section having a smaller area than a transversal section of the bars. Also described are a use of the product and a method for manufacture thereof.

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Description
CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of Italian Patent Application No. MI2010A001920, filed Oct. 20, 2010, pursuant to 35 U.S.C. 119(a)-(d), the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The following is a description of a reinforcing net structure for geotechnical applications, a use of the reinforcing net structure and a method for production of the said structure.

BACKGROUND OF THE INVENTION

In the geotechnical sector there is often a need to reinforce terrain or support steep slopes, with the aim of preventing landsliding and/or to guarantee greater stability of the terrain, even in the presence of natural events such as earthquakes, floods and others besides.

A first known technical solution comprises the use of reinforced nets made using woven metal wires, or wires coupled to one another such as to realize a net structure. These net structures are inserted or applied on the terrain or on the slope to be reinforced. Although these technical solutions have been widely used in the past, they exhibit a significant number of drawbacks related to production costs, difficulties connected with the process of weaving or coupling the metal wires and the complexity of realizing the net structure, as well as drawbacks connected to the structural capacity of the finished product and its ability to resist corrosive agents.

In addition to the above-described technical solution, plastic grids for geotechnical applications have become widespread, which grids are made using plastic materials such as high density polyethylene (HDPE). These net structures are obtained by extrusion of a first semi-finished piece having a plurality of through-openings. Then, by uni-directional stretching of the plastic material, net structure can be obtained which comprise a plurality of substantially rigid bars, joined to one another by a plurality of slim longitudinal elements having a certain flexing capacity with the aim of at least partially taking on a profile in accordance with the conformation of the terrain to be consolidated. The plastic net structures described are chemically inert and have a very pronounced resistance to traction in the direction of the longitudinal stretched elements, thereby guaranteeing network structures that are cheap to produce and which exhibit mechanical properties that are adequate for the geotechnical applications described above.

Further, the openings present in between two elongate longitudinal elements enable the earth to insert into the net structures, guaranteeing formation of a reinforced composite material. In practice, the reinforced earth, with the net structures described above, exhibits enhanced structural capacities in which the net structures can give the earth a greater rigidity and stability, by absorbing the stresses and re-distributing them in the reinforced mass of earth, guaranteeing, definitively, a greater static resistance and a greater dynamic resistance.

Although the product described has been a considerably success, given its mechanical properties, and the ability to be chemically inert combined with the possibility of a low-cost production, uni-directionally stretched reinforcing net structures at present on the market exhibit an accentuated mechanical resistance of the product in the stretched direction, but a limited structural flexibility as well as a relatively significant weight.

This type of characteristic, while enabling a wide range of different applications to be covered, as well as a sufficiently broad range of mechanical resistances to traction, requires the realization of a number of different products according to the required mechanical characteristics and the uses the product is to be put to.

Further, the weight of the product grows significantly in line with the requested mechanical resistance.

The poor flexibility and deformability of the longitudinal elements beyond their lie plane, as well as the rigidity of the non-stretched transversal bars, have an impact on the versatility of use of the product.

SUMMARY

In this situation, an object of the present invention is to provide a net structure for reinforcement of earth having high mechanical resistance and improved flexibility.

A further aim of the invention is to obtain a net structure product having a lower weight than the monolithic plastic net structures currently on the market.

A further aim of the invention is to obtain a net structure for geotechnical applications that can be easily applied and is adaptable to any arrangement whatsoever internally of the terrain or on the surface thereof.

A further aim of the invention is to obtain an artifact which, thanks to its intrinsic flexibility, can be arranged in several layers without losing structural continuity, even in low-temperature environmental conditions.

A further aim of the invention is to provide a net structure that is intrinsically capable of ensuring a high resistance even in a case of breakage of one or more elements.

One or more of the above aims are substantially attained by a reinforcing net structure for geotechnical applications, according to what is described in one or more of the accompanying claims.

Aspects of the invention are described herein below.

A 1st aspect relates to a product for reinforcing terrains, comprising a net structure made of a plastic material, the net structure having: a plurality of bars, reciprocally distanced, and a plurality of elongate elements which are transversal of the bars, the elongate elements being arranged between adjacent pairs of bars and being terminally fixed to the adjacent pairs of bars, wherein a plurality of the elongate elements exhibits a substantially wire-like structure with a transversal section having a smaller area than a transversal section of the bars.

In a 2nd aspect according to the first aspect, the elongate elements are able to flex freely about at least a first and at least a second direction which are perpendicular to one another and transversal with respect to a longitudinal development direction of each elongate element. In other words, the wire elements are not able to provide substantial flexional and compressive rigidity, but being wire-like provide a capacity of resistance to traction.

In a 3rd aspect, according to any one of the preceding aspects, each of the elongate elements is substantially rigid to traction.

In a 4th aspect, according to any one of the preceding aspects, numerous elongate elements, substantially of a same length, are arranged between two adjacent transversal bars, such as to define a maximum relative distance at which two adjacent bars can be positioned.

In a 5th aspect, according to any one of the preceding aspects, the length of each of the elongate elements arranged between two adjacent bars is comprised between 150 mm and 300 mm, optionally between 230 and 240 mm.

In a 6th aspect, according to any one of the preceding aspects, each elongate element exhibits a transversal section having an area of less than 5 mm2, optionally less than 1 mm2.

In a 7th aspect, according to any one of the preceding aspects, the transversal section of each elongate element exhibits a substantially circular profile, or substantially polygonal.

In an 8th aspect, according to any one of the preceding aspects, each elongate element exhibits a transversal section having an extension D1 in a first direction which is greater than or equal to an extension D2 of the transversal section in a second direction, such that a ratio between the extension in the first direction and the extension in the second direction D1/D2 is comprised in an interval of from 1 to 3, optionally in an interval of from 1 to 2.

In a 9th aspect, according to any one of the preceding aspects, each of the elongate elements, at least in a central tract thereof being 80% of the longitudinal extension thereof, exhibits a substantially constant transversal section area.

In a 10th aspect, according to any one of the preceding aspects, each of the elongate elements exhibits terminal portions having a transversal section with a progressively growing area starting from the central tract up to a connecting end to a bar of two adjacent bars.

In an 11th aspect, according to any one of the preceding aspects, two adjacent bars are connected by at least 40 longitudinal elements per linear meter of bar. In a case where the section of the wire-like elements is less than 1 mm2, adjacent bars will be connected by at least 200 wire-like elements per linear meter.

In a 12th aspect, according to any one of the preceding aspects, in the absence of external loads, the elongate elements are arranged substantially parallel to one another.

In a 13th aspect, according to any one of the preceding aspects, the product comprises a plurality of bars, from each of which elongate elements extend on each of two opposite flanks of the bars.

In a 14th aspect, according to any one of the preceding aspects, the elongate elements exhibit an aspect ratio defined as a ratio between a square of the length of each elongate element and a mean area of the transversal section of the elongate element, which is greater than 20000, optionally comprised between 4000 and 8000.

In a 15th aspect, according to any one of the preceding aspects, the bars exhibit an aspect ratio, defined as a ratio between the square of the length of the bar and a mean area of the transversal section of the bar which is at least 5 times, optionally 8 times, greater than the aspect ratio of the elongate elements.

In a 16th aspect, according to any one of the preceding aspects, the transversal section of the bars has a flattened conformation with an area comprised between 7 and 15 mm2, optionally comprised between 9 and 10 mm2.

In a 17th aspect, according to any one of the preceding aspects, the adjacent bars are positionable in a plurality of different relative positions, thanks to the flexibility of the elongate elements.

In an 18th aspect, according to any one of the preceding aspects, when two adjacent bars are arranged at a maximum distance condition from one another, substantially equal to the length of the elongate elements arranged between the two adjacent bars, adjacent bars and corresponding elongate elements between adjacent bars are arranged such as to define a plurality of through-openings.

In a 19th aspect, according to any one of the preceding aspects, when adjacent bars are in the said maximum distance condition, a frontal area of the through-openings is comprised in a range of between 75% and 95% with respect to a frontal area occupied by the product in its entirety.

In a 20th aspect, according to any one of the preceding aspects, the elongate elements are terminally fixed to adjacent bars by hot-coupling such as to define joining zones in which the plastic material of the elongate elements is co-penetrated into the plastic material of the bars, defining a monolithic product made of plastic material. Optionally the bars or the elongate elements are extruded and contemporaneously, or immediately after, the extrusion they are coupled to one another at the join zones.

In a 21st aspect, according to any one of the preceding aspects, the elongate elements are obtained by uni-directional longitudinal stretching, following the coupling thereof to the bars. In a 22nd aspect, according to any one of the preceding aspects, the elongate elements are stretched by at least 500% with respect to an initial length thereof.

In a 23rd aspect, according to any one of the preceding aspects, the elongate elements are made from a first polymer material and the bars are made from a second polymer material which is different to the first polymer material.

A 24th aspect concerns the use of a product according to any one of the preceding aspects, for consolidation of terrain.

In a 25th aspect, according to the preceding aspect, the product is applied to a surface zone of front of a slope.

In a 26th aspect, according to aspect 24 or 25, the product is folded upon itself once or more times, in order to define a multilayer structure, and is thus applied to the terrain to be consolidated.

A 27th aspect concerns the use of a plurality of products, each of which has the characteristics of one or more of aspects from 1 to 23, the products being applied in reciprocal superposition such as to form a multilayer structure for consolidating terrains.

In a 28th aspect, in accordance with aspect 27, the elongate elements of a first product are located parallel or transversal with respect to the elongate elements of a second product superposed on the first product.

In a 29th aspect, a process is provided, for example usable for manufacturing a product having the characteristics of one or more of aspects from 1 to 23, the process comprising steps of:

    • a. forming a plurality of the bars,
    • b. forming a plurality of elements located transversally to the bars,
    • c. hot-welding distanced zones of the elements at corresponding join zones provided on adjacent bars,
    • d. uni-directionally stretching the elements in order to form the elongate elements.

In a 30th aspect according to the 29th aspect, the bars and the elements are formed and joined continuously by hot extrusion of the bars and contemporaneous formation of the elements transversally to the bars in order to define a monolithic semi-finished grid-like workpiece.

In a 31st aspect according to the 29th and 30th aspect, in the semi-finished workpiece the elements have a substantially rectangular section, with a shorter side thereof in contact and connected with the surface of the bars.

In a 32nd aspect according to the 29th or the 30th or the 31st aspect, the elements, brought to a temperature of above 80° C., are stretched by at least 500% in order to form the elongate elements.

In a 33rd aspect according any one of aspects from the 29th to the 32nd to the bars are extruded an moved downstream the extrusion head according to a machine direction, while the elements are formed and transversally joined to the bars immediately upon the bars extrusion, and wherein the elements are stretched to form the elongated elements in correspondence of a stretching station applying a stretching action parallel to the elements and perpendicular or transverse to the machine direction.

BRIEF DESCRIPTION OF THE DRAWINGS

In the description that follows describes some aspects and embodiments are illustrated, by way of example, of a reinforcing net structure according to the invention. The description is provided with reference to the accompanying figures of the drawings, provided by way of non-limiting example, in which:

FIG. 1 is a plan view of a product in accordance with aspects of the invention arranged in a first configuration;

FIG. 1A is a perspective view from above of the product of FIG. 1;

FIG. 2 is an enlarged transversal section along line II-II of the product of FIG. 1;

FIGS. 2A-2E each show, in an enlarged view with respect to FIG. 1, a possible profile of a transversal section along line II-II of the elongate elements of the product of FIG. 1;

FIG. 3 is a view along line III-III of FIG. 1, in enlarged scale with respect to FIG. 1;

FIGS. 4A and 4B schematically show the product of FIG. 1 in a second and a third configuration;

FIG. 5 is a perspective view of a portion of the semi-finished workpiece for the formation of the product of FIG. 1;

FIG. 6 is a plan view of the portion of the semi-finished workpiece of FIG. 5;

FIG. 7 is a lateral view of the portion of the semi-finished workpiece of FIG. 5; and

FIG. 8 shows the product of FIG. 1 in a use condition.

 DETAILED DESCRIPTION

With reference to the accompanying figures of the drawings, 1 denotes in its entirety a product for reinforcing terrain, which can for example be used for retaining slopes or for reinforcing terrains requiring structural strengthening.

The product 1 comprises a net structure 2 made of a plastic material; for example, the structure 2 made of a plastic material can be realized using one or more of the following polymers: polyethylene, high density polyethylene (HDPE), polypropylene. The net structure 2 may optionally be obtained by a continuous process of formation as will be more fully described herein below, or by discontinuous processes such as injection molding.

The net structure 2 product 1 exhibits a plurality of bars 3, distanced from one another, which are substantially rigid structural elements able to offer a considerable resistance to traction in the longitudinal direction of development thereof, but also considerable resistance to shear, torsion and flexion. For example, each of the bars 3 exhibits a transversal sectional having an area comprised between 7 and 15 mm2. For example, the bars 3 may have an area comprised between 9 and 10 mm2. In terms of geometry, the bars 3 exhibit a pronounced aspect ratio and a polygonal transversal section, for example, rectangular with rounded corners, or a flattened transversal section such as to guarantee a certain level of ability to flex, at least in one plane. In the example shown in FIG. 3 the transversal section of the bar 3 has a flattened conformation, for instance rectangular, with a width of between 3 and 6 mm and a thickness comprised between 1.5 and 3 mm.

Numerous elongate elements 4 are fixed to the bars 3, which elongate elements 4 are placed transversely to the bars 3 and extend on opposite sides thereof such as to conjoin with adjacent bars 3. More precisely, as shown in FIG. 1, numerous elongate elements 4 are arranged between adjacent pairs of bars 3, for example more than 200 per linear meter of bar, which elongate elements 4 are terminally fixed to the bars 3 such as to form a structure 2 having a plurality of bars 3 intervalled by series of elongate elements 4 transversally joined to pairs of adjacent bars.

The elongate elements spanning across two adjacent bars 3 exhibit a substantially wire-like structure having an area in transversal section that is substantially less than the area of the transversal section of the bars 3, such that the elongate elements 4 are able to flex freely about at least a first and at least a second direction, denoted by 5 and 6 in FIGS. 2A to 2E, perpendicular to one another and transversal to a longitudinal development direction of each elongate element 4.

The elongate elements essentially behave as wires and therefore provide resistance to traction, while they yield to flexion and torsion. According to an aspect of the invention, each of the elongate elements 4 is substantially rigid to traction and, thanks to the entity of the stretching that gives them a substantially wire-like conformation, it exhibits a high tensile breaking load: in particular with reference to polypropylene the tensile breaking load can exceed 39 N/mm2. For polyethylene, the tensile breaking load varies on the basis of the molecular weight distribution. On the basis thereof, tensile breaking load varies between 18 N/mm2 and 38 N/mm2. In particular, with an HDPE conformed like the elements 4, the tensile breaking load is greater than 22 N/mm2.

A plurality of elongate elements 4 are arranged between two adjacent transversal bars 3, elongate elements 4 being substantially equal in length such as to define a maximum relative distance at which two adjacent bars 3 can be positioned, which is equal to the length of the elongate elements 4. In this condition, shown in FIG. 1, the elongate elements 4 between adjacent bars 3 develop parallel to one another and transversally, for example perpendicularly, to the bars 3 (in a condition where the elongated elements are kept in straight configuration). Owing to the flexibility of the elongate elements 4, the bars 3 can however also be arranged in different relative positions with respect to the bar 3 of FIG. 1, i.e. as shown for example in FIG. 4A and FIG. 4B, where consecutive bars 3 are positioned such that the elongate elements 4 are straight but inclined with respect to the bars 3 (FIG. 4A) or arranged in curved lines (FIG. 4B). In other configurations the bars 3 may also be inclined with respect to one another, for example arranged in reciprocally-oblique lie lines, thanks to the flexibility of the elongate elements 4.

In greater structural detail, note that the elongate elements 4 and the bars 3 can be made of a same plastic material, such as polypropylene or HDPE. Alternatively, the bars 3 can be made of a first plastic material, for example high density polyethylene, and the elongate elements 4 can be made of a second plastic material such as polyethylene.

As regards the geometry, the length of each of the elongate elements arranged between two adjacent bars 3 is comprised between 150 mm and 300 mm, in order to allow considerable scope of relative movement between two adjacent bars 3. In the illustrated examples, where there are more than 200 elements per linear meter of bar 3, the length of each elongate element 4 is comprised between 230 and 240 mm. Further, each elongate element 4 exhibits a polygonal transversal section (e.g. square or rectangular as in FIGS. 2B and 2C), substantially circular (FIG. 2A), substantially elliptical (FIG. 2D), broadly lenticular (FIG. 2E) having in any case an average area of less than 1.5 mm2, with the aim of ensuring the above-mentioned characteristics of flexibility. For example, the area of the transversal section of each elongate element 4 at least at 80% of the longitudinal extension of the elongate element may be less than 0.8 mm2: for example 0.7 mm2 in the case of rectangular or square section, and 0.55 mm2 in the case of circular or elliptical section. Alternatively, in other embodiments each elongate element 4 may exhibit a transversal section having an average area of less than 5 mm2, for instance 2 mm2 or 4 mm2, again with the aim of ensuring the above -mentioned characteristics of flexibility. It should also be noted that the geometry of the transversal-section of the elongate elements 4, even in cases where the section is not circular or a substantially circular conformation, may be such that the relationship between the extension D1 of the transversal section of the elongate elements 4 in a first direction and the extension of the transversal section D2 of the elongate elements 4 in a second perpendicular direction (see FIGS. 2A-2E) is comprised within a range of from 1 to 3.

Further, the elongate elements 4, in a central tract 7 thereof of at least 80% of the overall longitudinal extension of the elongate element 4, may exhibit a transversal section that is substantially constant and of a minimal size, with an area of not more than 1 mm2. In some cases, the central section 7 having a constant transversal section can reach up to 85% or even 90% of the total extension of the elongate elements 4. Consecutively to the central section 7, each elongate element 4 may exhibit terminal portions 8 having a progressively increasing transversal section going from the central section 7 up to a connecting end 11 with one of two adjacent bars 3, where the transversal section of the connecting ends 11 exhibits a transversal section having a maximum area.

As can be seen in FIG. 1, numerous wire-like elongate elements 4 extend between two adjacent cross bars 3: for instance, adjacent bars 3 may be connected by a number of items per linear meter of 4 elongated upper bar 200, for example 210 wire-like elongate elements 4 per linear meter of bar 3.

The elongate elements 4 have an aspect ratio, defined as the ratio between the square of the length of the elongate element 4 and the mean area of transversal section also of the elongate element 4, that is significantly greater than the aspect ration of the bars 3: in particular, the elongate elements 4 exhibit an aspect ratio that is greater than 20000 and is typically comprised between 40000 and 80000, while the bars exhibit an aspect ratio that is typically greater than the aspect ratio of the elongate elements 4, as the bars 3 exhibit a longitudinal extension of 2 or more meters: for example the aspect ratio of the bars 3 can be 5 or even 8 times greater than the aspect ratio of the elongate elements 4.

As already mentioned, and as shown in FIG. 1 and FIGS. 4A, 4B, the product 1 can be placed in many different configurations thanks to the flexibility of the elongate element 4, in particular, because of the flexibility of the elongate elements 4, two adjacent bars 3 are positionable in a plurality of different relative positions in which, for example, the bars 3 can be parallel to one another, not parallel but not coplanar, not parallel and not coplanar, straight or curved. However, when two adjacent bars 3 are arranged in a condition of maximum distance between them (hereinafter referred to as the configuration of maximum extension, see FIG. 1), substantially equal to the length of the elongate elements 4 arranged between the two adjacent bars 3, the said adjacent bars 3 and the corresponding elongate elements 4 between the adjacent bars 3 are arranged such as to define a plurality of through-openings 9 also substantially parallel to one another. In this maximum-distance condition, the frontal area of the through-openings 9 defined between two adjacent bars 3 may be greater by 70% than the area occupied by the entire frontal area occupied by the whole product 1: for example, the frontal area of the through-openings 9, again with reference to the condition of maximum extension, can be comprised in a range of between 75% and 90% of the area occupied by the entire product 1. In other words, though there are numerous elongate elements 4 between two adjacent bars 3, when the product is in a position of maximum extension there is a considerable free area between adjacent bars 3, which means that the material used to make the product 1 is of a relatively small entity.

Use of the Product.

From an operational point of view the product 1 may be applied to terrain in need of consolidation, slopes or cliffs liable to slipping, in order to provide support to the loose surface of the terrain.

For example, the product 1 may be applied to a frontal part of a slope, essentially at a surface area thereof such as to provide consolidation and containment against the breaking-off of portions of terrain. The product 1 also offers the possibility of seeding and growth of grass and the like because of the large area left free between the elongate elements.

In addition, or alternatively to the above, the product 1 may be inserted into the matrix of land to be consolidated in order to strengthen its structure and better support and redistribute loads.

In use (on both the surface and inside the terrain) the product 1 may be folded back on itself once or several times, such as to define a multi-layer structure, and may be applied to land needing consolidation, or a plurality of products may be applied in reciprocal superposition in order to form a multilayer structure for the land consolidation. The elongate elements 4 of differentiated portions of a same product 1, or different products, may be placed parallel or transversally to one another.

Production of the Product.

The product 1 may be made of a non-woven textile in which the elongate elements 4 are terminally fixed to adjacent bars 3 by means of contemporaneous or substantially contemporaneous formation of the elongate elements 4 with the bars 3, or by hot-coupling of elongate elements 4 with the bars 3 during the actual formation of the product 1; once the bars 3 and 4 elements are coupled to one another, at least the elongate elements 4 can then be longitudinally stretched in order to arrive at the finished product, as described herein below.

In this way, at the join areas between the bars 3 and the elongate elements 4, the plastic material of the elongate elements 4 is indistinguishable from, or at least penetrates, the plastic material of the bars 3, thus defining a monolithic product made of a plastic material.

In more detail, according to a first manufacturing process, the item 1 may be obtained by molding a semi-finished workpiece (see FIG. 5) having a series of bars 3′ arranged transversally with respect to a series of elements 4′ such as to form a grated monolithic structure. Thereafter, by stretching the elements 4′ uni-directionally, for example in the direction 10 of FIG. 5, the product of FIG. 1 can be obtained, in which the bars 3 and the elongate elements 4 are joined in a single piece.

Alternatively, a plurality of bars 3′ may be formed by extrusion, and the elements 4′ can be contemporaneously or subsequently formed on the bars 3′. The elongate elements 4, visible for example in FIG. 1, may be obtained by means of unidirectional longitudinal stretching, following coupling by substantial co-extrusion of the elements 4′ and of the bars 3′. The stretching can be done for example in baths, where the semi-finished workpiece is brought to a temperature of about 90-95 degrees Celsius and the elongate elements 4′ are stretched to at least 500% of the initial length thereof.

In accordance with an aspect of the invention which can be applied to the described process, the elements 4′ (see FIGS. 5-7) are substantially rectangular in section with the short side in contact with and connected to the surface of the bars 3′. In this way, following the stretching the join areas are stretched substantially only in the material that forms elements 4′.

Independently of the formation process of the semi-finished workpiece of FIG. 5, the entity of the stretching of the elements 4′ determines the aspect ratio of the elongate elements 4. For example, the elements 4′ may be stretched to at least 500% greater than their initial length: a stretching range that is practicable for polyethylene or polypropylene comprised between 600% and 800%. During the stretching stage the elongate element 4′ or the whole semi-finished workpiece are maintained at a temperature comprised between 90 and 95° C.

It will be apparent to those skilled in the art that various modifications and variations can be made to the reinforcing net structure, its use, and the method of producing the reinforcing net structure of the present disclosure without departing from the scope of the invention. Throughout the disclosure, use of the terms “a,” “an,” and “the” may include one or more of the elements to which they refer. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only.

Claims

1. A product for reinforcing terrains, comprising a net structure made of a plastic material, the net structure having:

a plurality of bars, reciprocally distanced; and
a plurality of elongate elements which are transversal of the bars, the elongate elements being arranged between adjacent pairs of bars and being terminally fixed to the adjacent pairs of bars,
wherein a plurality of the elongate elements exhibits a substantially wire-like structure with a transversal section having a smaller area than a transversal section of the bars, the elongate elements being able to flex freely about at least a first and at least a second direction which are perpendicular to one another and transversal with respect to a longitudinal development direction of each elongate element.

2. A product for reinforcing terrains, comprising a net structure made of a plastic material, the net structure having:

a plurality of bars, reciprocally distanced; and
a plurality of elongate elements which are transversal of the bars, the elongate elements being arranged between adjacent pairs of bars and being terminally fixed to the adjacent pairs of bars,
wherein a plurality of the elongate elements exhibits a substantially wire-like structure with a transversal section having a smaller area than a transversal section of the bars, the elongate elements being able to flex freely about at least a first and at least a second direction which are perpendicular to one another and transversal with respect to a longitudinal development direction of each elongate element,
wherein each elongate element exhibits a transversal section having an area of less than 5 mm2,
wherein the elongate elements exhibit an aspect ratio, defined as a ratio of between a square of the length of each elongate element and a mean area of the transversal section of the elongate element, which is greater than 20000, and
wherein the transversal section of the bars has a flattened conformation with an area comprised between 9 and 15 mm2.

3. The product of claim 1, wherein the length of each of the elongate elements arranged between two adjacent bars is comprised between 150 mm and 300 mm.

4. The product of claim 3, wherein length of each of the elongate elements arranged between two adjacent bars is comprised between 230 and 240 mm.

5. The product of claim 1, wherein each of the elongate elements is substantially rigid to traction, wherein a plurality of elongate elements is arranged between two adjacent transversal bars, which plurality of elongate elements is substantially equal in length in order to define a relative maximum distance at which two adjacent bars can be positioned, and wherein thanks to the flexibility of the elongate elements given by each elongate element exhibiting a transversal section having an area of less than 5 mm2, adjacent bars are substantially freely positionable in a plurality of different relative positions within said maximum distance.

6. The product of claim 1, wherein the length of each of the elongate elements arranged between two adjacent bars is comprised between 150 mm and 300 mm.

7. The product of claim 1, wherein each elongate element exhibits a transversal section having an extension D1 in a first direction which is greater than or equal to an extension D2 of the transversal section in a second direction such that a ratio between the extension in the first direction and the extension in the second direction is comprised in an interval of from 1 to 3.

8. The product of claim 1, wherein each of the elongate elements, at least in a central tract thereof being 80% of the longitudinal extension thereof, exhibits a substantially constant transversal section area, and wherein each of the elongate elements exhibits terminal portions having a transversal section with a progressively growing area starting from the central tract up to a connecting end to a bar of two adjacent bars, the product exhibiting a plurality of bars from each of which bars extend elongate elements on each of the two opposite flanks of the bars.

9. The product of claim 1, wherein two adjacent bars are connected by at least 40 longitudinal elements per linear meter of bar, wherein the elongate elements, in absence of external loads, are arranged substantially parallel to one another.

10. The product of claim 2, wherein two adjacent bars are connected by at least 40 longitudinal elements per linear meter of bar, wherein the elongate elements, in absence of external loads except gravity, are configured to take a position where they result parallel to one another.

11. The product of claim 1, wherein the elongate elements exhibit an aspect ratio, defined as a ratio of between a square of the length of each elongate element and a mean area of the transversal section of the elongate element, which is greater than 20000.

12. The product of claim 11, wherein the bars exhibit an aspect ratio, defined as a ratio between the square of the length of the bar and a mean area of the transversal section of the bar which is at least 5 times greater than the aspect ratio of the elongate elements.

13. The product of claim 1, wherein the elongate elements exhibit an aspect ratio, defined as a ratio of between a square of the length of each elongate element and a mean area of the transversal section of the elongate element, which is comprised between 40000 and 80000; and wherein the bars exhibit an aspect ratio, defined as a ratio between the square of the length of the bar and a mean area of the transversal section of the bar, which is at least 8 times greater, than the aspect ratio of the elongate elements.

14. The product of claim 1, wherein the transversal section of the bars has a flattened conformation with an area comprised between 7 and 15 mm2.

15. The product of claim 5, wherein when two adjacent bars are arranged at a maximum distance condition from one another, substantially equal to the length of the elongate elements arranged between the two adjacent bars, wherein the adjacent bars and the corresponding elongate elements between adjacent bars are arranged such as to define a plurality of through-openings; and wherein when adjacent bars are in the said maximum distance condition, a frontal area of the through-openings is comprised in a range of between 75% and 95% with respect to a frontal area occupied by the product in its entirety.

16. The product of claim 1, wherein the elongate elements are terminally fixed to adjacent bars by hot-coupling such as to define joining zones in which the plastic material of the elongate elements is co-penetrated into the plastic material of the bars, defining a monolithic product made of plastic material, in which the elongate elements are obtained by uni-directional longitudinal stretching, following the coupling thereof to the bars, in which the elongate elements are stretched by at least 500% with respect to an initial length thereof.

17. The product of claim 1, wherein the elongate elements are made from a first polymer material and wherein the bars are made from a second polymer material which is different to the first polymer material.

18. Method of consolidating terrains, comprising applying the product of claim 1 to a surface zone of a front of a slope and wherein applying comprises one in the group of:

folding the product on itself once or more times, in order to define a multilayer structure, and applying this latter to the terrain to be consolidated, and
applying a plurality of the products in reciprocal superposing relation and forming a multilayer structure for consolidation of terrains.

19. A process of producing a product of claim 1, comprising steps of:

forming a plurality of the bars;
forming a plurality of elements located transversally to the bars;
hot-welding distanced zones of the elements at corresponding join zones provided on adjacent bars; and
uni-directionally stretching the elements in order to form the elongate elements,
wherein the bars and the elements are formed and joined continuously by hot extrusion of the bars and contemporaneous formation of the elements transversally to the bars in order to define a monolithic semi-finished workpiece in a grid form, and wherein the elements, brought to a temperature of above 80° C., are stretched by at least 500% in order to form the elongate elements.
Patent History
Publication number: 20120099933
Type: Application
Filed: Oct 20, 2011
Publication Date: Apr 26, 2012
Applicant: TENAX S.P.A. (Vigano (Lecco))
Inventors: Cesare BERETTA (Lomagna (LC)), Pierluigi MAGGIONI (Barzano (LC))
Application Number: 13/277,293
Classifications
Current U.S. Class: Net, Fabric, Or Sheet Type (405/302.7)
International Classification: E02D 3/00 (20060101);