Search

EP-4735693-A1 - RETICULAR STRUCTURE FOR GEOTECHNICAL APPLICATIONS AND PROCESS FOR THE REALIZATION OF THE SAME

EP4735693A1EP 4735693 A1EP4735693 A1EP 4735693A1EP-4735693-A1

Abstract

The present invention refers to a reticular structure (2) of plastic material for geotechnical applications comprising: first and second elements (3, 4) having an elongated conformation intersecting at nodes (5) to form meshes (6) and to define a uniplanar structure; a plurality of protuberances (7) emerging from at least one side of the reticular structure itself. The structure has first and second elements having respective cross-sectional area, the ratio of which is between 0.7 and 1.5.

Inventors

  • BERETTA, CESARE

Assignees

  • Tenax S.p.A.

Dates

Publication Date
20260506
Application Date
20240704

Claims (20)

  1. 1. Reticular structure (2) of plastic material for geotechnical applications, said reticular structure (2) comprising: a plurality of first elements (3) spaced apart and having an elongated conformation according to a first extension trajectory (T1), wherein each first element (3) has a predetermined cross section defined according to a plane orthogonal to the first extension trajectory of the respective first element (3), a plurality of second elements (4) spaced from each other and having an elongated conformation according to a second extension trajectory (T2) transverse to the first extension trajectory (T1) of the first elements (3), wherein each second element (4) has a predetermined cross section defined according to a plane orthogonal to the second extension trajectory of the respective second element (4), wherein said first and second elements (3, 4) intersect at nodes (5) to form meshes (6) and substantially define a uniplanar structure extending between a first and second surfaces (2a, 2b) opposite each other, wherein the reticular structure (2) comprises a plurality of protuberances (7) emerging from at least one side of the reticular structure itself, characterized by the fact that the ratio between a cross-sectional area of a first element (3), measured at an intermediate portion between two immediately consecutive nodes (5), and a cross-sectional area of a second element (4), also measured at an intermediate portion between two immediately consecutive nodes (5), is between 0.7 and 1.5.
  2. 2. Reticular structure according to claim 1 , wherein each first element (3) has, for at least 80% of a tract of said first element connecting two immediately consecutive nodes (5), a substantially constant cross section, wherein each second element (4) has, for at least 80% of a tract of said second element connecting two immediately consecutive nodes (5), a substantially constant cross section.
  3. 3. Reticular structure according to any one of the preceding claims, wherein the first elements (3) have a thickness (S1), optionally measured orthogonally to the first extension trajectory (T1) of said first element (3) and transversely to the second extension trajectory (T2) of the second elements (4), wherein the second elements (4) have a thickness (S2), optionally measured orthogonally to the second extension trajectory (T2) of said second element (4) and transversely to the first extension trajectory (T1) of the first elements (3), wherein the ratio between the thickness (S1) of a first element and the thickness (S2) of a second element (4) is between 0.7 and 1.5, optionally between 0.8 and 1.3.
  4. 4. Reticular structure according to any one of the preceding claims, wherein each protuberance (7) emerges from a respective node (5).
  5. 5. Reticular structure according to any one of the preceding claims, wherein each protuberance (7) is substantially laterally contained within a surface size of the node (5) from which the protuberance (7) itself emerges.
  6. 6. Reticular structure according to any one of the preceding claims, wherein protuberances (7) emerge from at least one of the first and second surfaces (2a, 2b) of the uniplanar structure.
  7. 7. Reticular structure according to any one of the preceding claims, wherein each protuberance (7) extends along a direction from a base (7a) to a top (7b) opposite the base (7a), wherein the base (7a) of the protuberance (7) is joined in a single piece to a respective node (5), optionally, the extension direction of each protuberance (7) is transverse to the first extension trajectory (T1) and the second extension trajectory (T2).
  8. 8. Reticular structure according to the preceding claim, wherein each protuberance (7) has a height (H) defined by the maximum distance between the base (7a) and the top (7b) of the same protuberance (7), wherein the height (H) of each protuberance (7) is more than 4 mm, optionally between 5 mm and 40 mm, even more optionally between 5 mm and 30 mm.
  9. 9. Reticular structure according to the preceding claim, wherein the ratio between the height (H) of a protuberance (7), optionally of each protuberance, and the thickness of the uniplanar structure is greater than 2, optionally is between 3 and 5.
  10. 10. Reticular structure according to any one of the preceding claims, wherein each protuberance (7) has a substantially rectangular parallelepiped or a truncated pyramid shape.
  11. 11 . Reticular structure according to any one of the preceding claims, wherein each protuberance (7) has a predetermined length (L1), optionally measured along the first extension trajectory (T1) of the first element (3) passing through the respective protuberance (7), wherein each protuberance (7) has a predetermined width (L2), optionally measured along the second extension trajectory (T2) of the second element (4) passing through the respective protuberance (7), wherein the ratio between the length (L1) to the width (L2) of a prominence (7) is between 0.8 and 1.2, even more optionally between 0.9 and 1.1.
  12. 12. Reticular structure according to any one of the preceding claims, wherein each protuberance (7) has, for at least 80% of its height extension, a substantially constant section.
  13. 13. Reticular structure according to any one of the preceding claims, wherein the minimum distance between two protuberances (7) immediately adjacent to and emerging from two respective nodes (5) connected by a tract of a first element (3) is equal to or less than the distance between two second elements.
  14. 14. Reticular structure according to any one of the preceding claims, wherein the ratio between the minimum distance between two immediately adjacent protuberances (7) emerging from two respective nodes (5) connected by a tract of a first element (3), and the distance between two second elements is greater than or equal to 1, optionally between 1 and 1.2.
  15. 15. Reticular structure according to any one of the preceding claims, wherein the minimum distance between two protuberances (7) immediately adjacent to and emerging from two respective nodes (5) connected by a tract of a second element (4) is equal to or less than the distance between two first elements.
  16. 16. Reticular structure according to any one of the preceding claims, wherein the ratio between the minimum distance between two immediately adjacent protuberances (7) emerging from two respective nodes (5) connected by a tract of a second element (4), and the distance between two first elements is greater than or equal to 1, optionally between 1 and 1.2.
  17. 17. Reticular structure according to any one of the preceding claims, wherein protuberances (7) only emerge from nodes (5).
  18. 18. Reticular structure according to any one of the preceding claims, wherein the first and second elements (3, 4) lie substantially on a single ideal lying surface, wherein each node (5) has, with respect to the ideal lying surface at the respective node (5), a predetermined size, wherein each protuberance (7) has a maximum size substantially equal to or less than the predetermined size of the node (5) from which the protuberance emerges, optionally said sizes of the node (5) and protuberance (7) are defined with respect to the ideal lying surface at the respective node (5).
  19. 19. Reticular structure according to any one of the preceding claims, wherein the ratio between a minimum distance (D72) between two protuberances (7) immediately adjacent to and emerging from two respective nodes (5) connected by a tract of a first element (3), and a distance (D2) between two second elements is greater than or equal to 1, optionally being between 1 and 1.2.
  20. 20. Reticular structure according to any one of the preceding claims, wherein the ratio between a minimum distance (D71) between two protuberances (7) immediately adjacent to and emerging from two respective nodes (5) connected by a tract of a second element (4), and a distance (D1) between two first elements is greater than or equal to 1, optionally being between 1 and 1.2.

Description

RETICULAR STRUCTURE FOR GEOTECHNICAL APPLICATIONS AND PROCESS FOR THE REALIZATION OF THE SAME DESCRIPTION FIELD OF THE INVENTION The present invention relates to a reticular structure for geotechnical applications that can be used for soil containment and/or drainage. The reticular structure may also be used for the reinforcement and/or consolidation of soils, such as natural and artificial structures, for example, slopes, barrier walls, rockfall valleys, railroad ballasts, road bottoms and parking areas. The present invention also concerns a process of making said reticular structure and its use. STATE OF THE ART Geogrids are common in the geotechnical field for soil reinforcement, containment and/or consolidation. Geogrids may be made by stretching (mono-directional or bi-directional) a starting semi-finished product consisting of a uniplanar slab having a constant thickness that is extruded and then drilled. Such geogrids have a uniplanar reticular structure having longitudinal and transverse elements which intersect at nodes. Such geogrids are, for example, described in the following patent applications/patents: US5419659A, US2004062615A1 , US3386876, US7407699B2, US6423394B1. Alternatively, geogrids may be made by co-extruding a series of first and second elements joined together to define a monolithic grid. The co-extruded grid is then stretched along one or more directions to define a monostretched or bi-stretched reticular structure. Such co-extruded geogrids are, for example, described in the patent applications No. US4662946A and No. US5753337A. The known geogrids are chemically inert and have excellent tensile strength in the direction of the stretched elements. In addition, the openings in the mesh defined by the reticular structure allow the soil to fit between the threadlike elements of the reticular structure, ensuring the formation of a reinforced composite material. In particular, geogrids are able to absorb stresses and redistribute them evenly in the soil ensuring greater static and dynamic strength of the entire reinforced structure. However, the Applicant noted that the above-mentioned known geogrids are substantially lacking in drainage capacity. Therefore, geogrids made of sheet material having, on the one hand, a substantially flat surface suitable for accommodating a woven-nonwoven filter element and, on the other hand, having an irregular surface with a plurality of protuberances suitable for defining a sort of three-dimensional reticular structure with high drainage capacity were developed. Such geogrids is described, for example, in PCT patent application No. WO 2020/165726 A1 : such geogrid is defined by a rectangular mesh reticular structure with a first and a second set of elongated linked elements. The first and/or second strands have, throughout their development, a sort of rib suitable for defining a of three-dimensional structure with drainage capabilities. A further example is described in U.S. Patent No. US 5,891,549, which shows a co-extruded reticular structure with rectangular meshes defined by a first and a second set of elongated linked elements. The reticular structure has, on the one hand, a plurality of ribs each of which extends in height from a node of the reticular structure while longitudinally it is connected to at least one of the elongated elements. In fact, each rib defines a projecting part of the node and also constitutes a part of the elongated element: the ribs are suitable for defining a of three-dimensional structure with draining capabilities. Although the reticular structures described in PCT Patent Application No. WO 2020/165726 A1 and U.S. Patent No. US 5,891,549 have good drainage capabilities, these are generally characterized by a hydraulic capacity strongly prevailing in one direction, particularly the direction of major sheet development. This characteristic may be a huge limitation of geogrid when applied on structures having different slope directions, e.g., parking lots, roads, structures dedicated to the collection of municipal solid waste. An additional limitation of known drainage geogrids is the large contact surface area suitable for engaging the woven-nonwoven filter element, a condition that reduces the nominal permeability of the woven-nonwoven significantly. Although the aforementioned drainage geogrids are used in the geotechnical filed, the Applicant noted that they are not devoid of drawbacks and therefore can be improved in some aspects. SCOPE OF THE INVENTION The scope of the present invention is therefore to solve at least one of the drawbacks and/or limitations of the previous solutions. A first object of the present invention is to provide a reticular structure having excellent drainage capabilities in multiple directions. It is then an aim of the present invention to provide a reticular structure for geotechnical applications that can be easily installed, in particular capable of adapting to any ground arrangement whi