JP4669303B2 - Shock absorbing structure - Google Patents

Description

  The present invention relates to a shock absorbing structure, and more particularly to a shock absorbing structure disposed between a slope and a retaining wall for damming collapsed earth and sand from the slope.

  FIG. 6 is a perspective view showing a construction state of a conventional retaining wall.

  Referring to the drawing, a retaining wall 61 made of, for example, a concrete structure is constructed on a ground surface 62 that is a predetermined distance away from the slope 63. The retaining wall 61 dams up the collapsed sediment caused by the collapse of the slope 63, landslide, etc., and the collapsed sediment flows out to the side of the structure near the slope 63 such as roads and private houses (to the left in the figure). It is provided to prevent this.

  FIG. 7 is an example of an experimental result assuming a case in which the collapsed sediment collides with the retaining wall in FIG. 6, and is a diagram illustrating a change with time of the load applied to the retaining wall. In the figure, the horizontal axis indicates the time elapsed from the time when the tip of the collapsed debris flow collides with the wall surface of the retaining wall, and the vertical axis indicates the magnitude of the load applied to the retaining wall.

  Referring to the figure, the load applied to the retaining wall increases rapidly from the moment (time 0 seconds) when the tip of the collapsed debris flow collides with the wall surface of the retaining wall, and reaches the peak load P 0.15 seconds later. . After that, the load applied to the retaining wall gradually decreases, and after 1 second from the collision, the load is almost constant. This result shows that even if the colliding with the retaining wall of the collapsing debris flow continues for more than 1 second, the dynamic load due to the collapsing debris flow is hardly applied to the retaining wall after one second after the collision. Is shown.

  Therefore, when there is a possibility that the existing retaining wall will fall due to the impact force of the collapsing earth and sand, the existing retaining wall of the existing retaining wall becomes larger with respect to the peak load P after the colliding with the collapsing earth and sand. It is necessary to take measures such as placing concrete on the surface to make the retaining wall thicker.

  As mentioned above, if the existing retaining wall is made thicker, it becomes possible to improve the stability of the retaining wall against the impact load of the collapsed earth and sand, but generally on the front side of the retaining wall (opposite the slope) In many cases, structures such as roads and private houses are adjacent to each other, and such measures may not always be possible.

  Therefore, instead of increasing the thickness of the retaining wall itself, a method has been proposed in which a cushioning material made of, for example, a rubber plate or the like is attached to the inclined wall surface of the retaining wall. With this method, construction can be performed with or without the structure on the front side of the retaining wall, and it is possible to prevent the existing retaining wall from falling by reducing the impact load caused by the collapsed earth and sand with a cushioning material. It becomes.

  However, in order to install such a cushioning material on the slope wall of the retaining wall, a certain amount of installation space is required between the retaining wall and the slope. There arises a problem that the damming effect of the collapsed earth and sand due to the retaining wall is not sufficiently exhibited.

  The present invention has been made to solve the above problems, and is arranged between the slope and the retaining wall to reduce the peak load caused by the collapsed sediment from the slope, and between the retaining wall and the slope. An object of the present invention is to provide an impact absorbing structure that can suppress the influence of the collapsed earth and sand on the storage space.

In order to achieve the above object, an invention according to claim 1 is an impact absorbing structure disposed between a slope and a retaining wall installed at a predetermined distance from the slope, the outer surface thereof. When the impact energy applied to is increased to a predetermined value or more, it includes at least one cushioning material that absorbs at least a part of the impact energy , and the cushioning material reduces the apparent volume by the deformation, It has a hollow shape, and at least a part of the outer surface is open, and further includes a sheet-like sheet body arranged so as to cover at least a part of the open cushioning material .

If comprised in this way, a part of impact energy of the collapsed earth and sand which arose by the collapse of a slope etc. will be absorbed with a buffer material. Further, the space between the inclined surface and the retaining wall is increased by the reduced volume of the cushioning material. Furthermore, intrusion of earth and sand into the buffer material is suppressed.

According to a second aspect of the present invention, in the configuration of the first aspect of the present invention, the cushioning material is formed so that the porosity is 70% or more and less than 100%.

  If comprised in this way, after a deformation | transformation of a buffer material, the storage space of the collapsed earth and sand between a slope and a retaining wall will approach the storage space in case there is no buffer material.

According to a third aspect of the present invention, in the configuration of the first or second aspect of the present invention, the cushioning material is formed so as to be crushed after being deformed.

  If comprised in this way, the volume of a buffer material will become smaller by the grinding | pulverization of a buffer material.

The invention of claim 4, wherein, in the constitution of the invention according to any one of claims 1 to 3, the shock absorber includes a plurality of cushioning material, cushioning material, which is arranged in a state of being stacked It is.

  If comprised in this way, the number and arrangement | positioning of a buffer material will become changeable.

As described above, the invention according to claim 1 reduces the peak load applied to the retaining wall from the collapsed sediment because a part of the impact energy of the collapsed sediment generated by the collapse of the slope is absorbed by the buffer material. Thus, it is possible to suppress the falling of the retaining wall. Further, since the space between the slope and the retaining wall becomes larger by the reduced volume of the buffer material, the influence on the storage space for the collapsed sediment between the slope and the retaining wall can be suppressed. Furthermore, since intrusion of earth and sand or the like into the buffer material is suppressed, the buffer material can be held in a deformable state and the buffer performance can be maintained. Further, when a slope collapse or the like occurs, impact energy from the collapsed earth and sand can be reliably transmitted to the buffer material, and energy absorption by the shock absorber is stabilized.

The invention of claim 2, wherein, in addition to the effect of the first aspect, after deformation of the buffer material, storage space collapse sediment between the inclined surface and the retaining wall is a reservoir space when no cushioning member Therefore, a sufficient amount of the collapsed sediment can be stored between the slope and the retaining wall, and the collapsed sediment is more prevented from flowing out beyond the retaining wall.

According to a third aspect of the invention, in addition to claim 1 or claim 2, according to the present description, by milling of the cushioning material, the volume of the buffer material becomes smaller, almost collapsed sediment the installation space of the buffer material It can be efficiently used as a storage space.

In addition to the effect of the invention according to any one of claims 1 to 3 , the invention according to claim 4 can change the number and arrangement of the cushioning materials, so that the size of the retaining wall and the collapsed earth and sand can be changed. The shock absorbing structure can be configured according to the storage space or the like. Further, the amount of shock energy that can be absorbed can be set depending on the number and arrangement of the cushioning materials, which is easy to use.

  FIG. 1 is a perspective view showing a schematic configuration of an impact absorbing structure according to a first embodiment of the present invention.

  Referring to the drawing, a retaining wall 1 made of, for example, a concrete structure is installed on the ground 2 at a position separated by a predetermined distance on the front side of the slope 3. The retaining wall 1 is provided to dam the collapsed earth and sand caused by the collapse of the slope 3 or the landslide as in the conventional example. And the shock absorption structure 10 is comprised on the ground 2 between a slope and a retaining wall.

  The shock absorbing structure 10 covers a plurality of box-shaped cushioning materials 12 stacked in a bed shape along the wall surface 4 on the slope 3 side of the retaining wall 1 and covers the outer surface of the stacked cushioning materials 12. And a sandproof sheet 11 laid. In this embodiment, the plurality of cushioning materials 12 all have the same configuration.

  2 is a perspective view showing a schematic configuration of a cushioning material used in the shock absorbing structure shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III shown in FIG.

  With reference to these drawings, the cushioning material 12 is formed so as to be deformed when the impact energy applied to the outer surface thereof exceeds a predetermined value, and to absorb a part of the applied impact energy. Yes. The cushioning material 12 is also formed so that the apparent volume is reduced during deformation, and the shock absorbing material 12 is crushed by applied impact energy when deformed more than a predetermined amount.

  As an example, in this embodiment, the cushioning material 12 is made of a molded product of high-stiffness synthetic resin such as polyethylene or polypropylene, and is formed in a substantially rectangular parallelepiped box shape having a hollow inside. An opening 14 having a substantially square shape in plan view is formed in the upper wall 13 of the cushioning material 12, and openings 16 a to 16 d having a substantially square shape in side view are formed in the side walls 15 a to 15 d, respectively. Each side is open. Further, almost the entire lower surface 17 of the cushioning material 12 is open. The cushioning material 12 is formed by setting dimensions such as the hollow portion, the opening, and the thickness of each portion so that the void ratio with respect to the apparent volume defined by the outer shape surface is 70% or more and less than 100%. ing.

  FIG. 4 is a diagram schematically showing a process of absorbing impact energy by the impact absorbing structure shown in FIG. 1, and FIG. 5 uses the impact absorbing structure according to the first embodiment of the present invention. In the case, it is the figure which showed the change of the load added to a retaining wall. In FIG. 4, the description of the deformed and crushed cushioning material is omitted for the sake of explanation. Further, in FIG. 5, the curve represented by the solid line in the figure shows the load change to the retaining wall in this embodiment, and the curve represented by the two-dot chain line is a conventional example for comparison. The load change to the retaining wall shown by (FIG. 7) is shown.

  First, referring to (1) of FIG. 4, in the state where the shock absorbing structure 10 is configured between the slope 3 and the retaining wall 1 as shown in FIG. Assuming that this occurs. At this time, the generated collapsed earth and sand 20 flows down along the slope 3, and its tip collides with the sandproof sheet 11 on the outer surface of the shock absorbing structure 10 on the slope 3 side. At this time, when the impact energy applied from the collapsed earth and sand 20 to the cushioning material 12 through the sandproof sheet 11 becomes a predetermined value or more, for example, the cushioning material 12 indicated by the oblique lines in FIG. Thus, the state shown in FIG. That is, in this process, a part of the energy of the collapsed earth and sand 20 is absorbed by the deformation and pulverization of the plurality of cushioning materials 12 indicated by the oblique lines in (1) of FIG. Moreover, in the state of (2) of FIG. 4, since the buffer material 12 is crushed, the storage space for the collapsed earth and sand 20 is increased. Therefore, compared with the state of (1) of FIG. More collapsed earth and sand 20 are stored between the slope 3.

  Next, when the collapsible earth and sand 20 further advances toward the retaining wall 1 from the state of (2) in FIG. The buffer material 12 is deformed and crushed, and the state shown in FIG.

  When the remaining cushioning material 12 shown in (3) of FIG. 4 is deformed and crushed by the collapsed earth and sand 20, as shown in (4) of FIG. The space is almost completely filled with the collapsed earth and sand 20, and all the loads from the collapsed earth and sand 20 are applied to the retaining wall 1.

  Here, referring to FIG. 5 as well, as described above, when the shock absorber 10 as described above is disposed between the retaining wall 1 and the inclined surface 3, a plurality of cushioning materials constituting the shock absorber 10 are provided. 12 gradually absorbs the energy of the collapsed sediment 20 while being deformed and pulverized in order. Therefore, as shown by the solid line in FIG. 5, the load applied to the retaining wall 1 rises more slowly than the conventional example shown by the two-dot chain line immediately after the collapsing of the collapsed earth and sand 20 to the shock absorber 10. The peak load applied to the retaining wall 1 becomes P ′ smaller than the peak load P in the conventional example at a time T after 0.15 seconds from the collision between the collapsed earth and sand 20 and the shock absorber 10. In addition, after time T, the load applied to the retaining wall 1 gradually decreases, and becomes substantially constant at the same size as the conventional example after 1 second after the collision.

  In addition, after the shock absorbing material 12 is deformed and pulverized to be in the state shown in FIG. 4 (4), the sandproof sheet 11 is deformed together with the collapsed earth and sand 20 deposited between the slope 3 and the retaining wall 1. If the crushed cushioning material 12 is removed, a new cushioning material 12 is installed as shown in (1) of FIG. 4 and the shock absorber 10 is installed, the peak load of the retaining wall 1 is similarly reduced. Thus, it is possible to protect the retaining wall 1 repeatedly.

  As described above, since a part of impact energy at the time of the collision of the collapsed earth and sand 20 caused by the collapse of the slope 3 is absorbed by the buffer material 12, the retaining wall 1 conventionally needs to have a strength of P or more. However, in this embodiment, the retaining wall 1 may have a strength of P ′ or more and P or less. Therefore, without increasing the thickness of the retaining wall 1, it is possible to reduce the load applied to the retaining wall from the collapsed earth and sand 20 and suppress the falling of the retaining wall 1.

  In addition, the shock absorbing material 12 is crushed after being deformed when the impact energy applied to the outer surface at the time of collision between the collapsing earth and sand 20 and the shock absorbing structure 10 exceeds a predetermined value. At the time of deformation, the apparent volume is reduced. As a result, the space between the slope 3 and the retaining wall 1 is increased by the reduced volume of the cushioning material 12, so that the influence on the storage space for the collapsed earth and sand 20 between the slope 3 and the retaining wall 1 is suppressed. Will be. Further, when the cushioning material 12 is pulverized, the volume of the cushioning material 12 becomes smaller. Therefore, as shown in (4) of FIG. 4, the installation space for the cushioning material 12 is substantially used as a storage space for collapsed earth and sand. Can be used. In particular, in this embodiment, the porosity of the cushioning material 12 is set to be 70% or more and less than 100%, so that the collapsed sediment 20 is stored between the slope 3 and the retaining wall 1. The space approaches the storage space when there is no buffer material 12. Therefore, a sufficient amount of the collapsed earth and sand 20 can be stored between the slope 3 and the retaining wall 1, and the collapsed earth and sand 20 can flow beyond the retaining wall 1 to the structure side such as a private house or a road. It is suppressed.

  Furthermore, although the shock absorbing structure 10 is configured by stacking a plurality of hollow box-shaped cushioning materials 12 in a platform shape, the retaining wall 1 can be changed to a desired number and arrangement. It is possible to configure the shock absorbing structure 10 according to the size, the storage space of the collapsed earth and sand 20, and the like, and the amount of energy that can be absorbed can be easily adjusted.

  And in this embodiment, although each outer surface of the buffer material 12 is formed so that it may open | release, the sand-proof sheet | seat 11 is laid so that the outer surface of the piled up several buffer material 12 may be covered. . Thereby, since the penetration | invasion of the earth and sand etc. to the buffer material 12 is suppressed, the earth and sand etc. are blocked in each hollow inside of the buffer material 12, and the deformation | transformation of the buffer material 12 is prevented. Therefore, it is possible to maintain the cushioning performance by always holding the cushioning material 12 in a deformable state by the sandproof sheet 11. Further, when the collapsible earth and sand 20 is generated due to the collapse of the slope 3 or the like, the impact energy of the collapsible earth and sand 20 can be reliably transmitted to the buffer material 12 via the sandproof sheet 11, and the energy by the shock absorber 10. Absorption is performed stably.

  In the first embodiment, the material and shape of the cushioning material are specified, but it is not always necessary to configure in this way, and when the impact energy applied to the outer surface becomes a predetermined value or more. As long as at least a part of the applied impact energy can be absorbed by deformation, other materials may be used to form other shapes. In that case, you may form a buffer material so that it may return to the shape before a deformation | transformation after removal of the accumulated collapsed earth and sand.

  Moreover, in said 1st Embodiment, although the impact-absorbing structure is equipped with the sand-proof sheet laid so that the upper surface of the piled up several buffer material may be covered, there may not be a sand-proof sheet.

  Furthermore, in the first embodiment, the cushioning material has a hollow shape, and at least a part of the outer surface is opened. However, even if the outer surface of the cushioning material is not necessarily opened, the cushioning material has a predetermined value or more. If it can be deformed when subjected to impact energy, the same effect can be obtained.

  Furthermore, in the first embodiment described above, the porosity of the cushioning material is set to be 70% or more and less than 100%. However, even when the porosity is set to less than 70%, the collapse occurs. Although the storage space for earth and sand is reduced, it is possible to construct an impact absorber that can reduce the peak load of the retaining wall.

  Furthermore, in said 1st Embodiment, although the shock-absorbing structure is comprised by piling up a some buffer material in the shape of a platform, if the shock-absorbing structure is provided with at least one shock-absorbing material, good. Needless to say, when the plurality of cushioning materials are stacked, the cushioning material is not necessarily limited to the shape of a platform, and may be stacked in other external shapes. Furthermore, if the buffer material has a connection structure, a more stable buffer effect can be exhibited.

  Furthermore, in the above first embodiment, the cushioning material is formed so as to be crushed after being deformed, but if it can be deformed so that the volume is close to the minimum even if not necessarily crushed, The same effect is demonstrated.

  Furthermore, in the first embodiment, the cushioning material is formed in a rectangular parallelepiped box shape, but may be formed in other shapes such as a honeycomb shape.

  Furthermore, in the first embodiment described above, the same one is used for the plurality of stacked cushioning materials, but it is not always necessary to configure in this way. A plurality of shock-absorbing materials having different magnitudes of impact energy may be prepared, and these may be combined as necessary to constitute the shock absorber.

  Further, in the first embodiment described above, the cushioning material is disposed only in a part of the space between the retaining wall and the slope, but it is not always necessary to configure in this manner, and the entire space is not affected. A shock absorbing structure may be configured by disposing a buffer material. Moreover, you may install a shock absorbing material away from a retaining wall.

  Furthermore, in said 1st Embodiment, it is good also as a structure which covers opening with a sheet | seat etc. for every buffer instead of laying a sand-proof sheet | seat. Even if a metal mesh or the like is attached to cover the opening on the outer surface of the cushioning material, or the openings are formed in a grid pattern with appropriate intervals instead of providing openings in the cushioning material, It is possible to prevent large earth and sand from entering.

It is the perspective view which showed schematic structure of the impact-absorbing structure by 1st Embodiment of this invention. It is the perspective view which showed schematic structure of the shock absorbing material used for the impact-absorbing structure shown in FIG. It is sectional drawing of the III-III line shown in FIG. It is the figure which showed typically the absorption process of the impact energy by the impact-absorbing structure shown in FIG. It is the figure which showed the change of the load added to a retaining wall in the case of using the impact-absorbing structure by 1st Embodiment of this invention. It is the perspective view which showed the construction state of the conventional retaining wall. FIG. 7 is an example of an experimental result assuming a case where collapsing earth and sand collides with a retaining wall in FIG. 6, and is a diagram showing a time change of a load applied to the retaining wall.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Retaining wall 3 ... Slope 10 ... Shock absorption structure 11 ... Sand-proof sheet 12 ... Buffer material 20 ... Collapsed earth and sand In addition, the same code | symbol in each figure shows the same or an equivalent part.

Claims (4)

A shock absorbing structure disposed between a slope and a retaining wall installed at a predetermined distance from the slope,
It is deformed when the impact energy applied to the outer surface becomes a predetermined value or more, and comprises at least one cushioning material that absorbs at least a part of the impact energy ,
The buffer material has an apparent volume reduced by the deformation, has a hollow shape, and at least a part of the outer surface is open,
Furthermore, the impact-absorbing structure further provided with the sheet-shaped sheet | seat body arrange | positioned so that the said open | released part of a buffer material may be covered at least . The buffer material, porosity is formed to be less than 100% 70% claim 1 shock absorbing structure according. The shock absorbing structure according to claim 1 or 2 , wherein the cushioning material is formed so as to be crushed after the deformation. The shock absorber includes a plurality of the cushioning materials,
The shock absorbing structure according to any one of claims 1 to 3 , wherein the cushioning material is arranged in a stacked state.

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