JP4185877B2 - Rock fall prevention wall - Google Patents

Description

  The present invention relates to a rock fall prevention wall for preventing roads, railways, buildings, and the like in mountainous areas and steep slopes from falling rocks.

Conventionally, as a cushioning material that prevents damage caused by falling stones directly against a rockfall prevention wall and absorbs an impact used for the rockfall prevention wall having a buffering action, (1) JP-A-8-68016 or Sand (sand cushion) is used as disclosed in Japanese Patent Publication No. 6-26566, or (2) foam synthesis as described in Japanese Patent Application Laid-Open No. 9-88015 or Japanese Patent No. 26455481. Use a resin material, or (3) use a composite material of sand, foam , or sand as described in JP-A-2000-144644, or (4) Japanese Utility Model Publication No. 6-74611. Use old tires as described in the official gazette, or (5) use cushioning materials in which rubber or resin is blocked in a solid or hollow cross section as described in Japanese Patent No. 2654811. Ri, have used (6) as described in JP-A-9-242025, cushion material filled with shock-absorbing material. Further, (7) Japanese Patent Application Laid-Open No. 2003-221810 describes a cushioning material using wood chips. Further, (8) Japanese Patent Application Laid-Open No. 2003-55933 also discloses a method of using a unit block in which wood is filled in a frame made of a shape steel and a wire mesh.
JP-A-8-68016 Japanese Utility Model Publication No. 6-26566 JP-A-9-88015 Japanese Patent No. 2645481 JP 2000-144644 A Japanese Utility Model Publication No. 6-74611 Japanese Patent No. 2645481 Japanese Patent Laid-Open No. 9-242025 JP 2003-221810 A JP 2003-55933 A JP 2001-336048 A

When the cushioning material constituting the rock fall prevention wall is sand, its weight is heavy and the transportation cost to the construction site is high. In addition, when the cushioning material is a foamed synthetic resin material, there are problems such as high material costs, and since it is a substance that is not compatible with the natural environment, it costs chemical treatment when the cushioning material is damaged. There's a problem. Further, in the case of an old tire, there is a problem that rainwater accumulates in the tire and mosquitoes are generated. In the case of a shock absorber made of a rubber material, a resin material or a synthetic resin, there is also a problem that the price is high.

  When using a unit block filled with wood in a frame made by attaching a wire mesh to a steel frame assembled in a cube, give rigidity and strength for transportation and handling of the unit block filled with wood. For this reason, the frame body tends to be reinforced with shape steel or the wood is stuffed without gaps, so that the weight is heavy and the buffer performance is not sufficiently exhibited, and there is still a problem in workability on site.

  The present invention provides a buffer material for the rock fall prevention wall body by a square hollow columnar body having four sides formed of a steel wire mesh that can self-hold the shape, thereby providing a buffer that is economical, has good workability, and enables rapid construction. An object is to provide a rock fall prevention wall having a mechanism.

  In order to solve the above-mentioned problem advantageously, the present invention is configured as follows.

The rock fall prevention wall according to the first aspect of the present invention has four surfaces formed by a steel wire mesh that is configured to be capable of self-maintaining by welding or combining meridians and parallels. A prismatic hollow columnar body that deforms and exhibits a buffer function is configured, and a plurality of the rectangular hollow columnar bodies are disposed on a surface that receives the rockfall, thereby forming a rockfall prevention wall body, and the square hollow columnar body The above-mentioned steel wire mesh which constitutes is a combination mesh body of meridians and parallels made of a steel wire formed in a spiral shape.

A second invention is characterized in that, in the first invention, one or a plurality of rod-shaped timbers are included in the hollow portion of the square hollow columnar body.

According to a third invention, in the first or second invention, a support frame body is constituted by a plurality of support columns that are arranged at a predetermined interval in the vertical direction and a plurality of transverse beams connected to the support columns, and the support frame body A rock fall prevention wall main body is configured by fixing a plurality of the square hollow columnar bodies on a surface that receives the fall rock.

According to a fourth aspect of the present invention, in the first or second aspect, a plurality of pillars that are arranged in the vertical direction at predetermined intervals are provided, and a plurality of rectangular hollow pillars are provided across at least two of the pillars. Are arranged in a horizontal direction and stacked and fixed in multiple stages, whereby a rock fall prevention wall main body is configured on the surface that receives the rock fall.

A fifth invention is characterized in that, in any one of the first to fourth inventions, a plurality of arranged square hollow columnar bodies are provided toward a surface that receives rock fall.

A sixth invention, in any one invention of the first to fifth, the surface receiving the rock fall plurality arranged the rectangular hollow pillar, further provided an impact load dispersing bearing plate, or impact load distribution The present invention is characterized in that a square hollow columnar body overlapped on a supporting plate is provided.

According to the present invention, as the cushioning material for the rock fall prevention wall, a square hollow columnar body using a wire mesh knitted with a spiral wire composed of four surfaces with a steel wire mesh capable of self-holding the shape is used. Because it is very lightweight compared to other cushioning materials, and it is rich in transportability and on-site workability, it can be easily and rapidly constructed even in a mountainous area where a heavy machine such as a large crane cannot enter. Further, when a falling rock collides, the collapsing energy can be absorbed by collapsing the square hollow columnar body, so that a remarkable effect of exhibiting a very excellent buffering performance is exhibited. Therefore, this superior shock-absorbing performance reduces the force acting on the pillars and foundations when falling rocks. Therefore, the support frame body and foundation structure of the rockfall prevention walls can be made compact and small, further improving workability and economic efficiency. Can also be improved .

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
1 and 2 show a first embodiment of the present invention, FIG. 1 is a partially longitudinal side view showing a rock fall prevention wall having a buffer mechanism, and FIG. 2 is a front view showing a part of FIG. is there.

  In this embodiment, a number of pillars 4 such as H-shaped steel are tilted upright and spaced apart from a substantially flat reinforced concrete foundation 3 constructed on the ground 2 below the steep slope side 1. Are fixed to the foundation 3 by anchor bolts 5 or the like, and a holding column 6 made of H-shaped steel or the like is erected on the back side of the column 4, and the upper end of the column 6 is connected to the column 4 is detachably fixed by a bolt / nut 7 or the like, and the lower end portion of the retaining column 6 is seated on the foundation 3 and fixed by an anchor bolt 5 or the like.

  On the steep slope 1 side of the front surface of the support column 4, a mold member 8 as a horizontal horizontal beam made of H-shaped steel or the like is disposed at right angles so as to extend in the vertical direction and extend in the horizontal direction. The flange 4a on the front surface side of the support column 4 and the flange 8a on the rear surface side of the mold member 8 are detachably fixed by bolts and nuts 7 or the like to constitute the support frame body 11 of the rock fall prevention wall main body 10. Yes. The front surface side of the mold member 8 is a buffer surface side that receives falling rocks.

  The rock fall prevention wall main body 10 has a square hollow columnar body 12 (illustrated in an example using the spiral mesh 12c in FIG. 7) having four surfaces made of steel wire mesh placed on a mold material 8 spaced vertically. The upper end part 8 and the lower end part 8 are fixed by a U-shaped bracket or a mounting bracket 9 such as a bolt or nut, or an appropriate wire or the like wound around the outer periphery of the columnar body. The rock fall prevention wall 13 which comprises is comprised.

5 to 11 show a reference example of a rectangular hollow columnar body serving as a buffer layer of the rock fall prevention wall 13 and a configuration example of the first and second rectangular hollow columnar bodies 12 .

A rectangular hollow columnar body 12 according to the reference example shown in FIG. 5 is a straight steel wire (which is abbreviated as a normal steel wire) having a predetermined strength and thickness, and a meridian (one intersecting wire) 14 and a latitude line. (The other wire rod intersecting) Four sides are formed by a welded wire mesh 12a welded to an intersecting portion 16 of 15. Although both ends of the rectangular hollow columnar body 12 are open in the drawing, both ends may be closed with the same steel wire metal mesh as the four surfaces, or a metal mesh or a lid made of a material different from the four surfaces. Further, the four surfaces of the square hollow columnar body 12 are formed by bending a single welded wire mesh 12a at right angles at four corners of a rectangular cross-sectional view, connecting the ends thereof, or bending them substantially into a U-shape. The two-part welded wire mesh 12a faces each other and is arranged in a four-sided shape, and the two ends thereof can be connected by welding, bolt / nut connection fittings, connecting cords, or other commonly used connecting means. . Further, the two-part welded wire mesh 12a bent in a substantially L shape is faced and arranged in a four-sided shape, and the two ends thereof are connected by the same connecting means as described above to constitute the square hollow columnar body 12. You can also.

  According to the square hollow columnar body 12 shown in FIG. 5, the four sides are made of wire mesh, so it is very lightweight, and has excellent transport performance and on-site workability. Simple and rapid construction is possible even in places where heavy machinery cannot enter. The rectangular hollow columnar body 12 is constructed in advance in a factory and only the assembly and installation of the spiral net is performed at the construction site, so that the construction period can be remarkably shortened and the construction cost can be reduced.

  In addition, when a falling rock collides with the square hollow columnar body 12 of FIG. 5, the collision energy can be absorbed by collapsing the square hollow columnar body 12, so that a remarkable effect of exhibiting a very excellent buffering performance is obtained. Show. Therefore, because of this excellent buffering performance, the force acting on the support pillar 4 and the foundation 3 when falling rocks is reduced, so that the mold material 8 and the foundation structure of the falling rock prevention wall can be made compact and small, further improving the workability. Economic efficiency can also be improved.

6 and 7 show corners according to the first and second configuration examples configured by using the spiral wire meshes 12b and 12c (details are shown in FIGS. 9 and 10) using steel wires formed in a spiral shape. The mold hollow columnar body 12 is shown. Spiral wire rods that do not have a cavity in the center (shown in FIG. 8) engage with each other when a horizontal spiral wire rod or a vertical spiral wire rod is combined so that the crests and troughs engage each other to form a net. When the misalignment is regulated by the ridges and valleys that meet, a strong net having a stable shape is obtained. A form in which this mesh body is formed into a cylindrical shape is disclosed in Japanese Patent Application Laid-Open No. 2001-336048, and its use as a pillar material or pipe material is shown. The use as a buffer material for absorption has not been studied.

  6 and 7, the steel wire formed in the spiral shape is knitted using a longitudinal meridian 14a and a lateral latitude 15a. 6 and FIG. 7 is different from that of FIG. 6 in that the spiral wire mesh 12c of FIG. 7 is knitted in a close-packed state with meridians 14a and latitude lines 14b (details are shown in FIG. 11). In the spiral wire mesh 12b, the meshes are coarsened by thinning out the meridian lines 14a and the latitude lines 15a from the spiral wire mesh 12c of FIG. 7 at a ratio of 2 out of 4 (details are shown in FIG. 10). By changing the mesh as shown in FIG. 6, the strength and buffering performance of the square hollow columnar body 12 can be changed, and the design can be changed (details will be described later).

  If the spiral wire used in the present invention is a steel wire, the material and size are not limited, but from the viewpoint of strength, workability, and assembly workability, for example, a wire made of mild steel with excellent workability is used, and the wire diameter is It is desirable that the outer diameter of the spiral is 1 to 5 mm, the spiral outer diameter is about twice the wire diameter, and the spiral pitch is 5 to 8 times the wire.

  Further, if plated steel wire is used, durability can be enhanced from the viewpoint of weather resistance and anticorrosion, so that the performance such as the buffer performance does not change over time, and the stable performance by the wire mesh is maintained.

  Details of the spiral metal meshes 12b and 12c constituting the rectangular hollow columnar body 12 of FIGS. 6 and 7 will be described with reference to FIGS. As shown in FIG. 8, the spiral wire rod (steel wire) 17 has a spiral shape in which a crest 18 and a trough 19 having the same shape are repeated relative to each other in the axial direction, and the trough 19 is a spiral central axis A−. It is a wire that turns to a position in contact with A or a position close thereto. BB is a spiral central axis.

  A spiral wire mesh 12c shown in FIG. 11 or a spiral wire mesh 12b shown in FIG. 9 is manufactured by weaving spiral wire rods (steel wires) 17 shown in FIG. 8 using meridians 14a and latitude lines 15a. The spiral wire mesh 12b shown in FIG. 9 is manufactured by thinning out the meridians 14a and the parallels 15a from the close-packed spiral wire mesh 12c shown in FIG.

The four sides of the rectangular hollow columnar body 12 according to the first and second configuration examples shown in FIGS. 6 and 7 are formed by bending one spiral wire mesh 12b, 12c at right angles at four corners of a rectangular sectional view. The two end parts are connected to each other, or two members bent into a substantially U-shape are faced to be arranged in a four-sided shape, or two members bent into a substantially L-shape are faced to be arranged in a four-sided shape. The two ends can be connected to each other. In any case, it is necessary to connect the ends, but by using the spiral wire mesh 12b, 12c, welding can be made unnecessary by using the connecting spiral wire (one example of the connecting means is shown in FIG. 10). Further, since the mesh is formed of the spiral wire rod, the spiral wire mesh 12b and 12c can be disassembled and the wire rod partially replaced by rotating the spiral wire rod so as to move forward or backward even after being knitted into the spiral mesh. And can be added easily.

  That is, as shown in FIG. 10, when connecting the ends of the spiral wire mesh 12b, in which the two adjacent pieces are left in advance and the two pieces between them are thinned, the positions of the ends are shifted from each other, and At the portion of the thinned two latitude lines 15a, the latitude line 15a protruding from the other spiral wire mesh 12b is made to rotate so as to be knitted to the meridian 14a of the one spiral wire mesh 12b. At the connecting portion 22 that is inserted into the meridian 14a at the end and bites into each other with the comb teeth facing each other, the connecting helical wire 20 is rotated and entered from the direction perpendicular to the protruding distal end portion 23. By doing so, the ends of the spiral wire mesh 12 can be connected to each other.

  The case where the end portions of the close-packed spiral metal mesh 12c in FIG. 11 are connected can be performed in substantially the same manner as described above. In other words, the ends of the spiral wire mesh 12c are arranged opposite to each other, and the latitude lines 15a at one end of the spiral wire mesh 12c are rotated every other line to advance, and the latitude lines 15a at the corresponding positions are rotated at the other end side. By retreating, the end portions are connected to each other such that the comb teeth face each other and bite each other, and by rotating the connecting helical wire from the direction perpendicular to the connecting portion, The ends of the spiral wire mesh 12c can be connected to each other. The ends of the spiral wire mesh 12c may be connected by welding, a bolt / nut connecting bracket, a connecting rope, or other commonly used connecting means.

  According to the experiment results of the inventors of the main body, the spiral wire mesh composed of a spiral wire rod having no hollow in the center has an extremely high energy absorption capacity when subjected to an impact force compared to a welded wire mesh or a diamond wire mesh. Has been confirmed.

  The experiments conducted by the main inventors are described below. In the experiment, a welded wire mesh, a diamond wire mesh, and a spiral wire mesh were prepared for each 1 m × 1 m, and a weight of 100 kg, 200 kg, and 300 kg was dropped from a height of 2 m in the center to investigate the impact absorbing performance. As an evaluation index, acceleration in rebound (repelling) immediately after falling of the weight is measured, and it can be evaluated that the smaller this is, the better the shock absorbing ability is. FIG. 14 shows the acceleration in the rebound immediately after dropping the weight. The welded wire mesh had the highest acceleration, and the weight penetrated (the mesh was broken) at 200 kg. The diamond-shaped wire mesh was almost the same as the welded wire mesh, and the weight penetrated (the mesh was broken) at 200 kg. On the other hand, the spiral wire mesh has a considerably smaller acceleration than other wire meshes, and even with a 300 kg weight, the weight could be sufficiently held without penetrating (breaking the mesh). This indicates that the shock absorbing capacity of the spiral net is extremely high compared to a general net. It has been found that the shock-absorbing ability of the spiral wire mesh is excellent because it absorbs the impact energy when the spiral wire is stretched when it receives an impact force.

  Since the hollow columnar body 12 is hollow in the columnar body, wood such as thinned wood may be included in this space, and this enables effective use of the thinned wood and the like, and also improves the landscape. Is also connected. At this time, in order to exhibit the buffering performance of the rectangular hollow columnar body 12, it is preferable to arrange the wood roughly leaving a space inside.

Second Embodiment
3 and 4 show a second embodiment of the present invention, FIG. 3 is a partially longitudinal side view showing a rock fall prevention wall having a buffer mechanism, and FIG. 4 is a front view showing a part of FIG. is there.

  In the second embodiment, the rectangular hollow columnar body 12 (illustrated in the example using the spiral mesh 12c in FIG. 7) is horizontally installed. The first embodiment in which the square hollow columnar body 12 is vertically installed. It is different from the form. With this difference, the structure of the support frame 11 is slightly different. That is, in the second embodiment, the square hollow columnar body 12 having the same configuration as that of the first embodiment is installed in a horizontal direction on a large number of pillars 4 such as H-shaped steels standing at intervals on the foundation 3. The plurality of rectangular hollow columnar bodies 12 constitute a buffer mechanism, and a rock fall prevention wall 13 is provided.

  At this time, it is preferable that the square hollow columnar body 12 is fixed to at least two columns 4. If the square hollow columnar bodies 12 are arranged in a staggered manner as shown in FIG. As a weak point.

  According to the second embodiment, the square hollow columnar bodies 12 can be installed so as to be stacked in the horizontal direction from below, and therefore, the workability is very good. Since the rectangular hollow columnar body 12 is a hollow columnar structure using a wire mesh, it is lightweight and excellent in strength and deformation performance. Therefore, the horizontal hollow columnar body 12 in the first embodiment can be omitted. Other operations are the same as those in the first embodiment.

  In the first and second embodiments shown in FIGS. 1 and 3, an example in which the rectangular hollow columnar body 12 arranged vertically and horizontally is provided on the front surface of the support frame 11 is shown. However, the present invention is not limited to this, and a plurality of layers may be provided. By providing a plurality of square hollow columnar bodies 12, the impact force can be absorbed by the square hollow column state 12 of each layer, so that the buffering function can be doubled.

<Third Embodiment>
FIGS. 12 and 15 show a third embodiment, in which a plurality of square hollow columnar bodies are provided on a surface that receives rock fall.
As shown in FIG. 12, when stacking a plurality of layers of rectangular hollow columnar bodies, for example, in the case of two layers, a plurality of small rectangular hollow columnar bodies 25 with small rigidity are formed on the layer in contact with the support frame 11. The rectangular hollow columnar body 24 having high rigidity may be stacked on the surface that receives the falling rocks, and may be installed so as to cover a plurality of the rectangular hollow columnar bodies 25 having low rigidity. By using the square hollow columnar bodies having different rigidity in this way, the square hollow columnar body 25 having a plurality of lower rigidity, which is positioned under the high-rigidity square hollow columnar body 24 through which the impact load of falling rocks is large. The energy can be absorbed efficiently and energy can be absorbed efficiently, and the local impact force to the falling rock protection wall can be prevented from increasing. As shown in FIG. 10 and FIG. 11, the square hollow columnar bodies having different rigidity can be achieved by changing the density of the method of knitting the spiral mesh, the wire diameter of the wire constituting the spiral mesh, This can also be achieved by changing the pitch. In addition, it is possible to enclose a rod-like thinned material in a square hollow columnar body or to put a thinned thinned wood chip.
Further, in the case of three layers, as shown in FIG. 15, the rectangular hollow columnar body 25 having a low rigidity is overlapped on the surface that receives the falling rock further above the above-described large rectangular hollow columnar body 24, and In addition, by installing so as to cover a plurality of square hollow columnar bodies 24 having high rigidity, it is possible to reduce the collision acceleration of falling rocks first in the square hollow columnar body 25 having the small rigidity of the uppermost layer, which is preferable. .

<Fourth embodiment>
FIGS. 13 and 16 show a fourth embodiment, in which a square hollow columnar shape is superimposed on a surface for receiving falling rocks of a square hollow columnar body, and further on an impact load distribution support plate or an impact load distribution support plate. This is a case where a body is provided.
Further, as a method of dispersing the impact load of falling rocks, in addition to the above method, as shown in FIG. 13, an impact load dispersion support plate 26 (example using a deck plate) is used. You may install and attach so that it may cross over twelve. As the impact load distribution support plate 26, it is preferable to use a plate-like plate member made of a material having rigidity sufficient to disperse the impact load, such as a deck plate made of steel, an expanded metal or a veneer plate.
Further, as shown in FIG. 16, a corner having a large rigidity is formed on the upper layer of the rectangular hollow columnar body 25 having a small rigidity for distributing the load and the support plate 26 for impact load distribution, that is, on the surface directly receiving the impact force by the falling rock. If the mold hollow columnar body 24 is installed to have a three-layer structure, the impact load can be absorbed more effectively. That is, by installing the square hollow columnar body 24 having high rigidity on the surface that directly receives the impact force, the impact acceleration of the falling rock is reduced and the impact force is relaxed, and the impact load distribution support plate 26 underneath is provided. However, the relaxed impact force is received, and the impact force is dispersed and transmitted to the square hollow columnar body 25 having a lower layer of lower rigidity. And, the square hollow columnar body 25 having a small rigidity at the lowermost layer deforms the dispersed impact force as a whole, thereby further reducing the impact force and effectively absorbing the energy. Become.

It is a partially vertical side view which shows the rock fall prevention wall of 1st Embodiment. It is a front view which shows a part of FIG . It is a partial vertical side view which shows the rock fall prevention wall of 2nd Embodiment. FIG. 4 is a front view showing a part of FIG. 3. It is a perspective view of the reference example of a square-shaped hollow columnar body. It is a perspective view of the 1st structural example of a square-shaped hollow columnar body. It is a perspective view of the 2nd example of composition of a square hollow columnar object. (A) is a perspective view of a spiral wire, (b) is an explanatory side view of the spiral wire, (c) is an OO, PP, QQ, and RR arrow portion of (b). It is explanatory drawing of. It is a front fragmentary view of the 2 thinning-out spiral wire mesh used for the square hollow columnar body of the 1st example of composition . It is explanatory drawing which shows the aspect which connects a 2 thinning-out spiral wire mesh using the helical wire for connection. It is a front fragmentary view of the close-packed spiral wire mesh used for the square hollow columnar body of the second configuration example . It is a partial vertical side view which shows the rock fall prevention wall of 3rd Embodiment. It is a partial vertical side view which shows the rock fall prevention wall of 4th Embodiment. It is the figure which showed the difference in the shock absorption capability by the kind of wire mesh. It is a partially vertical side view which shows another rock fall prevention wall of 3rd Embodiment. It is a partially vertical side view which shows another rock fall prevention wall of 4th Embodiment.

Explanation of symbols

1 Steep slope side
2 Ground 3 Concrete foundation
4 Prop 4a Flange 5 Anchor Bolt 6 Holding Pillar 7 Bolt / Nut 8 Mold Material 8a Flange 9 Mounting Bracket
DESCRIPTION OF SYMBOLS 10 Falling rock prevention wall main body 11 Support frame 12 Square hollow columnar body 12a Welded wire mesh 12b Spiral wire mesh 12c Spiral wire mesh 13 Falling stone prevention wall
14 Meridians 14a Meridians 15 Latitude 15a Latitude 16 Crossing
DESCRIPTION OF SYMBOLS 17 Spiral wire 18 Mountain part 19 Valley part 20 Connection spiral wire 21 Tip 22 Connection part 23 Wire tip 24 Stiff square hollow column 25 Stiff square hollow column 26 Impact load distribution support plate

Claims (6)

Square wire hollow that is formed by welding or combining meridians and parallels to form a four-sided steel wire mesh that can be self-maintaining, and deforms the steel wire mesh due to falling rocks and exhibits a buffer function A columnar body is formed, and a plurality of the square hollow columnar bodies are disposed on a surface for receiving rockfall, thereby forming a rockfall prevention wall main body, and the steel wire mesh constituting the square hollow columnar body is spiral. A rock fall prevention wall characterized in that it is a combined net of meridians and parallels made of steel wire formed into a metal. 2. The rock fall prevention wall according to claim 1, wherein one or a plurality of rod-shaped timbers are included in the hollow portion of the square hollow columnar body. A support frame body is composed of a plurality of support columns that are arranged at predetermined intervals in the vertical direction and a plurality of cross beams connected to the support columns. The rock fall prevention wall according to claim 1 or 2, wherein the body is fixed to form a rock fall prevention wall main body. Provided with a plurality of support columns that are arranged in the vertical direction at predetermined intervals, a plurality of rectangular hollow columnar bodies are horizontally disposed over at least two of the support columns, and are stacked and fixed in multiple stages. The rock fall prevention wall according to claim 1 or 2, wherein a rock fall prevention wall main body is formed on the surface that receives the fall rock. 5. The rock fall prevention wall according to claim 1, wherein the plurality of square hollow columnar bodies are provided in a plurality of layers toward a surface for receiving rock fall. Further, an impact load distribution support plate is provided on the surface of the plurality of square hollow columns that receive the falling rocks, or a square hollow column that is stacked on the impact load distribution support plate is provided. The rock fall prevention wall of any one of Claims 1-5 characterized by these.

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