Structure that absorbs impact energy

Abstract

We propose a reinforced shock-absorbing structure. [Solution] The structure for absorbing impact energy includes a dike (15) having a first surface (10) exposed to impact, and reinforcing materials distributed within the dike (15) and having a friction interface with the material of the dike. The reinforcing materials consist of strip-shaped strips arranged in a first reinforcing region (12) adjacent to the first surface (10), and include a first main reinforcing material (16) arranged at an angle of less than 45° with respect to the first surface such that the main strength direction forms an angle of less than 45° with respect to the first surface, and secondary reinforcing materials arranged in a direction transverse to the first surface.

Description

Detailed Description of the Invention

[0001] [Technical Field] The present invention relates to the field of structures for protecting against accidental impacts of large objects, such as rockfalls in mountains or train derailments.

[0002] [Prior Art] Two types of solutions have been conventionally used to protect roads or buildings from accidental impacts.

[0003] First, protective nets arranged to block the colliding object are known. These nets are generally made of metal and can stop impacts of up to 8 megajoules (MJ) by deforming, and have the advantage of being compact. However, they are accompanied by many problems. These structures cannot function multiple times and require significant maintenance. After stopping the projectile, the anchor points are damaged and repairs must be carried out. The maintenance of these structures is costly and is carried out frequently. Also, generally, due to the corrosion of the nets placed outdoors, maintenance is required. Since these structures are generally located in difficult-to-access places, this suppression is more important. On the other hand, these less attractive structures tend to damage the landscape. In many regions, simply installing a protective net is not sufficient to make the land where the falling objects are exposed suitable for construction and tends to protect the landscape. These requirements are important in mountainous areas where the pressure on the land is increasing.

[0004] Finally, the effectiveness of these nets is non-uniform and they cannot absorb impacts over their entire range. For example, the impact on the anchor posts is not properly absorbed.

[0005] In French Patent Application Publication No. 3083551 A1, such protective nets relate to Marlon-type structures composed of substantial dikes that enable complete blockage of impact. These structures are capable of absorbing higher energy levels, up to 30 megajoules, and require little maintenance. However, these structures occupy a large footprint on the ground and are not practically usable.

[0006] International Publication No. 2019 / 091508 A1 and International Publication No. 2017 / 077313 A1 disclose gabions, i.e., metal cages filled with stone or sandbags, which do not necessarily require protection against strong impacts. Nevertheless, when such impacts occur, the metal elements of the cage are subjected to tension. To prevent excessive damage, it is necessary to rely on the low deformability of the contained stone, but the absorption of impact energy by the structure remains considerably limited.

[0007] European Patent Application Publication 1520933 A1 discloses a technology relating to deformable materials such as recycled tires, in which gabion-like facing elements are placed on the front of a reinforced soil structure. Thus, in the event of a stone impact, damaged individual facing elements can be replaced.

[0008] [Technical problems] Therefore, there is a need for a durable, compact, and aesthetically pleasing impact-absorbing structure that blends well with the surrounding landscape.

[0009] [Overview of the prefecture] This invention proposes a reinforced shock-absorbing structure that allows for the lateral dispersion of impact energy, thereby reducing the thickness of the structure. When the use of reinforcing materials is known, these reinforcing materials are conventionally positioned in the depths of the embankment, parallel to the direction in which the reinforcing materials are expected to be subjected to action.

[0010] [Overview of the prefecture] The object of the present invention is an impact energy comprising a dike having a first surface exposed to impact, and reinforcing materials distributed within the dike and having friction interfaces with the dike material. The reinforcing materials include a first reinforcing region located adjacent to the first surface and having a primary strength direction that forms an angle of less than 45° with respect to the first surface.

[0011] The structure may be of the Marlon type. The structure may be positioned perpendicular to the trajectory on which the impact is expected to travel. The impact requiring protection occurs, for example, with a strong component in the direction normal to the first surface. The structure may also be a retaining wall positioned to prevent the collapse of stepped terrain in response to substantial impacts.

[0012] The embankment is preferably composed of soil, but may also have any type of material that readily absorbs mechanical energy by interacting with reinforcing materials. Preferably, the embankment has a specific particle size that allows it to have desirable mechanical behavior.

[0013] In one embodiment, for example, suitable for locations where strong impacts are likely to occur in opposite directions, the embankment has a second surface facing a first surface. The reinforcing material may include a second reinforcing material positioned in a second reinforcing region adjacent to the second surface, having a primary strength direction that forms an angle of less than 45° with respect to the second surface.

[0014] The configuration of the absorption structure allows friction generated by the first reinforcing member (or second reinforcing member, if applicable) to significantly contribute to the dissipation of energy from strong impacts occurring on the first surface (or second surface). This friction is due to the deformation of the first surface (or second surface) caused by the impact. The position of the first reinforcing member (or second reinforcing member) within the first reinforcing region (or second reinforcing region) adjacent to the first surface (or second surface), and the orientation of the first reinforcing member (or second reinforcing member) relative to the first surface (or second surface), allows for effective dissipation without requiring insertion into deep parts of the structure. Thus, it is possible to obtain an absorption structure that is not very bulky perpendicular to a surface that may be struck by an object with high kinetic energy. The footprint on the ground is, for example, 10 m or less, preferably 5 m or less, and more preferably 3 m or less.

[0015] The reinforcing material used is preferably a one-dimensional type. That is, the mechanical strength exhibited by the reinforcing material is, in most cases, exerted in a single strength direction, and the mechanical strength exhibited by the reinforcing material in other directions is negligible compared to the mechanical strength exerted in that single strength direction. The reinforcing material is, for example, in the form of a strip, not a sheet or an expanded grid. The primary strength direction of the reinforcing material corresponds to the direction in which mechanical stress tends to propagate when the reinforcing material is subjected to action. This is generally the direction of the maximum dimension of the reinforcing material.

[0016] These reinforcing members are arranged such that their primary strength directions are substantially parallel to each other and to one or more faces of the structure. The primary strength direction of the first reinforcing member may be parallel to the first face of the embankment, and optionally parallel to the second face. On the other hand, in certain cases, the primary strength directions may be slightly offset from the plane of the first face, or, if the first face is not plane, from the plane tangent to the first face. However, the angles formed between these primary directions and the first face must be acute such that the projection of the reinforcing member onto the first face is longer than the projection of the reinforcing member perpendicular to the first face. This provides a good energy dissipation effect in the event of a vertical impact.

[0017] Therefore, if the surface is non-planar, the reinforcing members extending from each other may, for example, form polygons that match the shape of the surface. The curved surface may preferably have a large radius of curvature.

[0018] The placement of reinforcing members perpendicular to the front normal, and therefore perpendicular to the direction of the impact from which energy is absorbed, allows for the lateral dispersion of the mechanical energy of the impact and a reduction in the thickness of the structure over which it acts.

[0019] To avoid weakening the embankment by creating a preferred slip surface, it is preferable to avoid placing the first reinforcing material in the center of the embankment as much as possible. For this reason, the reinforcing material is mainly placed near one or more faces of the structure that may be subjected to impact. This does not rule out the presence of reinforcing material in the center of the embankment, but such placements are infrequent. The distribution of reinforcing material is non-uniform in the thickness direction of the structure. The density of reinforcing material is lower in areas further from the impact surface than in the first (or second) reinforced areas of the embankment. While these are standard, very locally, exceptions can be seen due to structural irregularities or deformations of the structure, for example, where multiple reinforcing materials are placed close together, thereby causing a localized increase in the density of these reinforcing materials. Therefore, the density of reinforcing material does not necessarily decrease continuously. Preferably, the reinforcing material is placed at regularly spaced intervals but only in reinforced areas that are close to at least one face of the structure. There may be areas that are not so close to the faces of the structure, in which the reinforcing material may be placed at wider intervals, or there may be no reinforcing material at all. However, these regions may have other types of reinforcing materials, for example, reinforcing materials oriented along the thickness direction of the structure.

[0020] The following features may be implemented at will. These features may be implemented independently of each other or in combination. - The first and / or second reinforcing members are positioned horizontally. - The first surface of the embankment is covered with facing. This facing can be of any type. This facing can improve the mechanical properties of the structure, and if it is, for example, green or mineral facing, it can also create a sense of unity with the landscape. - The secondary reinforcements are positioned laterally to the first surface. These secondary reinforcements may have any orientation. These secondary reinforcements can, for example, reinforce the structure against forces that the structure can withstand in a static state without impact. Therefore, one may consider zigzag-shaped reinforcements connecting the front and rear surfaces, or reinforcements oriented perpendicular to the front surface and connecting the first and / or second reinforcements. - The first reinforcing material includes a metallic reinforcing material, a reinforcing material made of a polymer material, a geogrid-type reinforcing material, or a geotextile-type reinforcing material. - At least some of the first reinforcing members are arranged in continuous segments along the main strength direction of those reinforcing members, and have overlapping regions that overlap with each other between the segments. In these overlapping regions, there may be embankment material between the continuous segments of the first reinforcing members.

[0021] In general, the structure can absorb impacts having energy exceeding 2 megajoules, preferably exceeding 5 megajoules. This energy corresponds to the pressure that a protective marlon placed in a mountain can conventionally withstand.

[0022] Energy dissipation due to friction is desirable for maintaining the performance of the structure. Therefore, the arrangement of reinforcing members is preferably designed to limit the fracture of the reinforcing members as much as possible. Multiple reinforcing members include those arranged such that their front surfaces are ductile and do not exhibit brittle behavior when subjected to normal impact.

[0023] An embodiment of such an arrangement consists of restricting the direct connection between the reinforcing members. Along the main strength direction, two reinforcing members arranged in successive segments are, for example, arranged in an overlapping region that overlaps with each other between the segments, and a layer of dike material is placed between the reinforcing members. Thereby, in order to avoid breakage of the reinforcing member, it is possible to generate friction and soften the transmission of lateral pressure. This mutually overlapping region correlates with the rigidity of the reinforcing member, the friction surface, and the breaking strength of the reinforcing member.

[0024] The maximum dimension of the reinforcing member is also important. From the perspective of elasticity that enables a structure to withstand multiple impacts without requiring repair, it is important not to use a reinforcing member of excessive dimension to prevent breakage.

[0025] [Brief Description of the Drawings] Other characteristics, details, and advantages of the present invention will become apparent by reading the following detailed description and analyzing the accompanying drawings.

[0026] [Fig. 1] is a cross-sectional side view of a structure according to an embodiment of the present invention.

[0027] [Fig. 2] is a cross-sectional side view of a structure according to another embodiment of the present invention.

[0028] [Fig. 3] is a cross-sectional side view of a structure according to another embodiment of the present invention.

[0029] [Fig. 4] is a cross-sectional side view of a structure according to another embodiment of the present invention.

[0030] [Fig. 5] is a front cross-sectional view of the structure, and the cross-section is on the plane V-V shown in any one of Figs. 1 to 4.

[0031] [Fig. 6] is a cross-sectional top view of the structure according to the embodiment of the present invention in Fig. 3.

[0032] [Fig. 7] is a cross-sectional top view of another embodiment of the structure according to the present invention in Fig. 3.

[0033] Figure 8 is a diagram similar to Figure 6, but showing the result after an energy collision.

[0034] [Description of Embodiments] As an example, the impact energy absorbing structure disclosed below takes the form of a protective marlon used to block falling rocks that can weigh up to several hundred metric tons, for example, near mountain trails. Such falling rocks can carry more than 6 megajoules (MJ) of energy.

[0035] This protective marlon has a first surface, i.e., a front surface 10, shown on the right side in Figures 1-4, and a second surface, i.e., a rear surface 20, shown on the left side. These front surface 10 and rear surface 20 may be substantially parallel, as shown in Figures 1 and 3. The rear surface 20 may also be inclined relative to the front surface 10, as shown in Figures 2 and 4.

[0036] The orientation of the rear surface 20 in Figures 2 and 4 allows for better dissipation of mechanical energy on the ground, but increases the footprint of the structure on the ground.

[0037] Although the front surface 10 is shown vertically in Figures 1 to 4, the front surface 10 may be inclined, particularly when it is necessary to increase the stability of the structure, to modify the footprint on the ground, or to adapt to an expected oblique impact trajectory. Specifically, it is preferable that the front surface be as perpendicular as possible to the impact trajectory.

[0038] The marlon of this embodiment comprises an earthen embankment 15 defined by a front surface 10 and a rear surface 20. Reinforcement members 16 have a friction interface with the embankment material. For example, in a direction perpendicular to the horizontal cross-section in Figures 1 to 4, the reinforcement members 16 are strips that are regularly distributed vertically, extend horizontally, and are horizontal to the front surface 10 and the rear surface 20. This orientation allows for the mechanical energy of impact to be preferentially dispersed laterally rather than through the thickness of the protective marlon.

[0039] The reinforcing members 16 are positioned in the area of ​​the embankment 15 that is most affected when there is an impact that must absorb energy. In the embodiments shown in Figures 1 and 2, the reinforcing members 16 consist of first reinforcing members 16 positioned in a first reinforcing region 12 adjacent to the front surface 10. In the reinforcing members of Figures 3 and 4, in addition to the first reinforcing region 12, a second reinforcing region 22 is provided near the rear surface 20. This second reinforcing region 22 includes a second reinforcing member 16. Generally, in the central region of the marlon, the reinforcing members 16 are not positioned parallel to the surface 10 and the rear surface 20. This prevents the marlon from being weakened by deforming it when there is an impact.

[0040] However, the secondary reinforcing members 18, which are positioned laterally relative to the front 10 and rear 20, may be incorporated into the embankment 15 to reinforce the whole structure. In particular, the secondary reinforcing members 18 may connect the front 10 and the rear 20.

[0041] The reinforcing members 16 may be placed along the entire width of the marlon. More preferably, the reinforcing members 16 are used in a manner that partially overlaps in continuous segments along the main strength direction, as shown in Figure 5. Each overlapping region 25 between two continuous reinforcing members 16 has the embankment material so that the reinforcing members 16 do not come into contact with each other. Thus, when subjected to impact, energy is transferred from one segment to the next by friction, gradually dissipating and simultaneously avoiding the fracture of the reinforcing members 16. This allows the marlon to withstand multiple consecutive impacts without requiring repair.

[0042] Ideally, as shown in Figure 6, the reinforcing members 16 are positioned perfectly parallel to the front and rear surfaces to distribute mechanical energy as much as possible laterally. However, for logistical reasons, or in particular to reinforce and / or protect specific parts of the marlon, the reinforcing members may have a slight angle (must be less than 45°) and may be pressed to some extent into the thickness of the structure, as shown in Figure 7. The reinforcing members are considered substantially parallel to the front 10 and rear 20, as their orientation remains primarily lateral. The primary strength direction of the reinforcing members 16 forms an angle of less than 45° with the front 10 and / or rear 20 of the embankment 15.

[0043] Similarly, the reinforcing member 16 may vary in height and may have a slight incline. This incline should preferably remain shallow in order to distribute energy as much as possible laterally.

[0044] Figure 8 is a similar depiction to Figure 6, showing the front surface 10 of the embankment, indicated at the bottom of the figure, after a powerful, localized impact. It can be seen that the energy was adequately dissipated laterally by the reinforcing material 16. The reinforcing material 16 did not rupture. The reinforcing material remains positioned in a configuration that can dampen other impacts.

[0045] Furthermore, the present invention is not limited to the embodiments disclosed above. This disclosure encompasses all different inventions that a person skilled in the art could conceive of within the scope of the protection rights desired by that person. [Brief explanation of the drawing]

[0046] [Figure 1] This is a cross-sectional side view of a structure relating to one embodiment of the present invention. [Figure 2] This is a cross-sectional side view of a structure according to another embodiment of the present invention. [Figure 3] This is a cross-sectional side view of a structure according to another embodiment of the present invention. [Figure 4] This is a cross-sectional side view of a structure according to another embodiment of the present invention. [Figure 5]This is a front cross-sectional view of the structure, and the cross-section lies on the plane VV shown in one of Figures 1 to 4. [Figure 6] Figure 3 is a cross-sectional top view of the structure according to an embodiment of the present invention. [Figure 7] Figure 3 is a cross-sectional top view of the structure according to an embodiment of the present invention. [Figure 8] This diagram is similar to Figure 6 after the energy collision.

Claims

1. A structure that absorbs impact energy, A levee (15) having a first surface (10) that includes the levee material and is subjected to impact, The reinforcing material is distributed within the embankment (15) and has a friction interface with the embankment material, The first surface (10) is covered with a facing, The reinforcing material consists of a strip-shaped strip placed in a first reinforcing region (12) adjacent to the first surface (10), and includes a first main reinforcing material (16) that is positioned at an angle of less than 45° with respect to the first surface, such that the main strength direction forms an angle of less than 45° with respect to the first surface. A structure comprising: a secondary reinforcing member arranged in a direction transverse to the first surface.

2. The structure according to claim 1, wherein the main strength direction of the first main reinforcing member (16) is parallel to the first surface of the embankment (15).

3. The embankment (15) has a second surface (20) that faces the first surface (10), The structure according to claim 1, wherein the reinforcing member is arranged in a second reinforcing region (22) adjacent to the second surface (20), and includes a second main reinforcing member (16) arranged at an angle of less than 45° with respect to the second surface such that the main strength direction forms an angle of less than 45° with respect to the second surface.

4. The structure according to claim 3, wherein the main strength direction of the second main reinforcing member (16) is parallel to the second surface of the embankment (15).

5. The structure according to claim 1, wherein the reinforcing member (16) is arranged horizontally.

6. The structure according to claim 1, wherein the first main reinforcing member (16) includes a metallic reinforcing member.

7. The structure according to claim 1, wherein the first main reinforcing member (16) includes a reinforcing member made of a polymer material.

8. The structure according to claim 1, wherein the first main reinforcing material (16) includes a geogrid type or geotextile type reinforcing material.

9. The structure according to claim 1, wherein at least some of the first main reinforcing members (16) are arranged in segments that are continuous along the main strength direction of the first main reinforcing members and have overlapping regions (25) that overlap with each other between the segments.

10. The structure according to claim 9, wherein in the overlapping region (25), the material of the embankment is located between the continuous segments of the first main reinforcing member (16).

11. The reinforcing material (16) is unevenly distributed within the structure. The structure according to claim 3, wherein the density of the reinforcing material is lower at locations away from the first and second surfaces than that of the first or second reinforcing region.

12. The first main reinforcing member (16) includes at least two strip-shaped segments that partially overlap each other in the overlapping region (25), The structure according to claim 1, wherein a portion of the embankment material is arranged between the two strip-shaped segments in the overlapping region (25).

13. The embankment (15) has a second surface (20) that faces the first surface (10), The structure according to claim 3, wherein the secondary reinforcing material connects the first surface (10) and the second surface (20).

14. The structure according to claim 3, wherein the secondary reinforcing material connects the first surface (10) and the second surface (20) and has a zigzag shape in the cross-sectional side view of the structure.

15. The structure according to claim 1, wherein the secondary reinforcing material is oriented perpendicular to the first surface (10).

16. The structure according to claim 3, wherein the secondary reinforcing member connects the first main reinforcing member (16) to the second main reinforcing member (16).

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