JP6140974B2 - Falling object protection device - Google Patents

Description

  The present invention relates to a fallen object protection apparatus that protects fallen objects such as falling rocks and avalanches from a slope.

As this type of prior art, for example, there is a rock fall protection device 100 shown in Patent Document 1 below (see FIG. 11).
The rock fall protection device 100 includes a plurality of support columns 101 erected at intervals in the slope width direction, an upper support rope 103 that is held by the plurality of support columns 101 and whose end is fixed to an anchor 102, and A lower support rope 104 and a wire mesh 105 disposed on the inclined valley side with respect to the support column 101 and having an upper edge and a lower edge connected to each support rope are provided. The wire mesh 105 catches falling rocks from the slope and prevents falling rocks on nearby roads.

  Moreover, between the support ropes 103 and 104 and the anchor 102, shock absorbing brake devices 103a and 104a are incorporated (see FIGS. 11 and 12). The brake devices 103a and 104a are composed of a steel loop pipe 110 and tightening members 111 assembled in the vicinity of both ends of the loop pipe 110, and support ropes 103 and 104 are inserted from one end of the loop pipe 110. After a section of the rope is wound in a loop shape, both ends of the loop pipe are tightly tightened together by the tightening member 111 to generate a frictional force between the rope and the inner surface of the loop pipe. In other words, it is a device that allows the rope to be stretched while driving the support rope with a friction force, and the impact of the falling rock is mitigated by extending the rope while driving the brake.

Moreover, as a protective net for a rockfall protective fence, for example, there is also an energy absorption type protective net shown in Patent Document 2 below.
In this protective net, each element wire is processed into a coil shape, and in the adjacent element wires, one element wire is inserted inside the other element wire, and these element wires are bent at each pitch. It is a protective net that is specially knitted so as to be inscribed without any damage.

Unlike conventional general-purpose rhombus metal meshes, this protective mesh is inscribed without being bent at the intersection, so that each strand is prior to elongation due to tensile load during impact action. Receives bending load at the intersection. For this reason, each strand undergoes elastic or plastic deformation at the intersection with falling rocks, and much of the collision energy is immediately absorbed by bending deformation of each strand at the intersection.
That is, not only is each element wire deformed in the direction of the line, but high energy absorption is obtained by positively bending each element wire at the intersection.

JP2009-024378 JP 2000-199210 A

  By the way, since the brake devices 103a and 104a described above apply the brake by using friction acting between the ropes, it takes time until the energy absorbing power is maximized. In other words, the braking device using friction is weak in initial braking and increases the amount of energy absorbed exponentially, so that it has not been able to sufficiently absorb the impact energy of falling rocks at the beginning of the collision with the highest energy amount.

  In addition, the above-mentioned rockfall guard fence is entangled with this point, and the impacted rope is insufficient, so the impacted rope extends more than necessary. For this reason, the protective net greatly protrudes toward the slope valley side with respect to the support column. Therefore, when installing a rock fall protection fence, the pillars had to be installed sufficiently separated from the road to be protected, and the installation location had to be selected on a slope with poor workability.

  In addition, the above-described energy absorption type protection network can be applied to compensate for the shortage of braking force, but this energy absorption type protection network promotes the deformation of each mesh and absorbs the impact, so that the conventional protection network is used. Compared to the above, it was easy to bend, and the effect of preventing the protection net from being pushed out was weak by simply replacing the existing protection net.

  The present invention has been made to solve such technical problems, and it is an object of the present invention to provide a fallen object protection device that is excellent in impact energy absorption performance and that prevents the protective net from projecting to the sloped valley side. .

In order to solve the above technical problem, the present invention is a falling object protection apparatus comprising a protective net that receives a falling object from a slope, and a support that supports the protective net,
In the protective net, each strand is formed in a spiral shape, and adjacent strands intersect without bending between both pitches,
The support column supports the protective net with a space on the slope mountain side.

  According to the fallen object protection apparatus of the present invention configured as described above, the energy absorption type protection net is provided as a protection net in which the strands intersect without bending. Further, the protective net is supported on the slope mountain side by a support, and a space is secured between the protective net and the support.

  For this reason, when a falling rock collides with the protective net, the collision energy is absorbed immediately after the collision with deformation of the protective net. In addition, the protection net is bent toward the slope valley side as the collision energy is absorbed, but the bending is substantially reduced by the width of the space secured between the support column and the protection net. That is, even if an energy absorption type protective net which is easy to bend is used, the protrusion to the sloped valley side with respect to the pillar is suppressed, so that the pillar can be installed away from the slope.

Further, the space may be a space for suppressing a collision of the protective net against the support column.
According to this configuration, even if the protective net is bent toward the slope valley side as the collision energy is absorbed, the collision of the protective net against the column is suppressed by the space secured between the protective net and the column.

The protective net may be a high-strength steel wire.
According to this configuration, in addition to the mesh shape rich in energy absorption, the tensile strength of the high-tensile steel wire can be imparted to the protective mesh. That is, the rigidity with respect to the broken net can be increased while maintaining a flexible network structure.

In addition, the support is provided with a support portion protruding from the support to the slope mountain side,
The protection net may be configured to be supported on the slope mountain side through the support portion.

  According to this configuration, the support portion projecting to the slope mountain side is provided, and the protective net is supported on the slope mountain side via the support portion. That is, a space corresponding to the protruding amount of the support portion is naturally secured between the support column and the protective net.

  Further, it has a horizontal rope that supports the protective net in the slope width direction and an anchor for fixing the horizontal rope, and absorbs an impact acting on the horizontal rope between the horizontal rope and the anchor. The structure provided with the impact absorption mechanism for doing may be sufficient.

  According to this configuration, the impact of falling rocks is transmitted to and absorbed by the impact absorbing mechanism through the horizontal rope as well as the energy absorption type protective net. Thus, the synergistic effect further reduces the urge of the protective net against the sloped valley side.

  Further, the impact absorbing mechanism includes an energy absorbing rope having a smaller longitudinal elastic modulus than that of the lateral rope and having a longer elongation than the lateral rope when compared with the same length. The energy absorption rope may be configured to be connected between the lateral rope and the anchor.

  In this configuration, since the collision energy is absorbed by the deformation of the rope itself without using the friction brake, the collision energy can be absorbed without loss immediately after the collision together with the energy absorption type protective net. That is, the collision energy can be efficiently absorbed at the initial stage of the collision with the highest energy amount.

  As described above, according to the present invention, it is possible to provide a fallen object protection device that is excellent in collision energy absorption performance and that prevents the protective net from protruding toward the sloped valley side.

The front view of the fallen object protection apparatus shown in this Embodiment. The top view of the fallen object protection apparatus shown to this Embodiment. The side view of the support | pillar shown to this Embodiment. The front view of the impact absorption mechanism shown in this Embodiment. The front view which shows the other specification of the impact-absorbing mechanism shown in this Embodiment. The front view which shows the other specification of the impact-absorbing mechanism shown in this Embodiment. The principal part enlarged view of the high tension | tensile_strength protection net | network shown to this Embodiment. The graph for comparing and evaluating the protection performance of the high-tension protection network shown in this embodiment. The figure which shows the test body (intersection strength test body) used in FIG. The side view which shows the other specification of the support | pillar shown in this Embodiment. The perspective view which shows the conventional rock fall protection fence. The perspective view of the brake device integrated in the conventional rockfall protection fence.

Hereinafter, the falling object protection apparatus 1 according to the present invention will be described.
The fallen object protection apparatus 1 shown in the present embodiment includes a plurality of support columns 10 erected in the direction of the inclined surface width (left and right direction) along the lower edge of the inclined surface. The support strut rope 2 for attracting and fixing to the strut, the strut reinforcement rope 3 which is a connecting member routed in the vertical direction with respect to the strut 10, and the upper side that is supported by each strut 10 and extends in the slope width direction A rope 4 and a lower horizontal rope 5, and a high-tension wire net 6 that is a high-tension protective net provided between the upper horizontal rope 4 and the lower horizontal rope 5 are provided.

  The support column 10 is made of a steel pipe having a main body portion 11 of φ114.3 mm and a wall thickness of 4.5 mm. It has been. Further, the support shaft 17a of the hinge is disposed so as to be orthogonal to the vertical direction of the slope, and is supported so as to be tiltable in the vertical direction with respect to the slope.

Further, the main body portion 11 of the support column 10 is provided with a bracket (face material support portion) 12 for assembling the various ropes described above.
The brackets 12 are provided at two locations, the top and bottom of the support column 10 and near the ground, and are welded so as to project to the slope mountain side with the support column 10 upright.
Further, U-shaped bolts 13 for connecting the column reinforcing ropes 3 are assembled to the tip portions of the brackets 12 and 12. The end portions of the column reinforcing rope 3 are connected to the brackets 12 and 12, respectively. The brackets 12 and 12 are connected to each other by the column reinforcing rope 3.

  The strut reinforcing rope 3 is a steel wire rope with 3 × 7φ18 and eye-finished at both ends. Further, the overall length of the bracket 12 is designed such that a space of 150 mm or more is secured between the support reinforcing rope 3 and the support body 11. Further, when the U-bolts 13 are tightened in a state where the support reinforcement rope 3 is assembled to the bracket 12, tension is applied to the support reinforcement rope 3, and the support reinforcement rope 3 is firmly stretched between the brackets 12 and 12.

A through bolt 14 is assembled to the head of the column 10. The through bolt 14 penetrates the head of the column 10 from the lateral direction, and the column holding rope 2 inserted from the column head is locked to the head of the column 10 by the through bolt 14.
Here, an eye processing having a ring (loop) larger than the diameter of the support column 10 is applied to the end portion of the support column rope 2, and the end portion of the support column rope 2 through which the column head is inserted passes through this end. By being hooked on the bolt 14, the strut retainer rope 2 is locked to the head of the strut 10 without sliding down from the head of the strut 10.

Next, the upper lateral rope 4 and the lower lateral rope 5 supported in the slope width direction will be described.
The upper horizontal rope 4 and the lower horizontal rope 5 are steel wire ropes of 3 × 7φ18, and are supported on the slope mountain side of the support column 10 via brackets 12 and 12 provided above and below the support column 10. Specifically, the horizontal ropes 4 and 5 are routed so as to pass the loop of the eye-processed portion (ring-shaped end portions 3b and 3c) of the column reinforcing rope 3 assembled to the bracket 12. That is, the horizontal ropes 4 and 5 are supported by the bracket 12 without being restricted in movement in the linear direction.

  Moreover, in the fallen object protection apparatus 1 shown in the present embodiment, an impact absorbing mechanism 50 for absorbing energy at the time of falling rock collision is provided for each of the ropes 2, 4, 5 excluding the support reinforcement 3. Yes. The ropes 2, 4, and 5 are fixed to the anchors via the shock absorbing mechanism 50. 1 and 2 are turnbuckles for attracting and fixing the ropes 2, 4 and 5 to the anchor side, and the turnbuckle 2a is not essential but necessary. Provided accordingly.

The shock absorbing mechanism 50 includes a steel general-purpose wire rope (for example, a hard steel wire twisted rope defined in JIS G 3525) and an energy absorbing rope (manufactured by Tokyo Steel) that exhibits a high energy absorbing power near the breaking load. ).
Specifically, a conventional general-purpose steel rope 52 having a surplus length of about 1.3 to 1.5 times that of the energy absorption rope 51 having an actual length of about 1 to 2 m is attached. Each end is caulked and bundled to the general-purpose steel rope 52 side.

  In addition, as the specification, both ends of the energy absorption rope 51 are caulked and bundled with both ends of the general-purpose steel rope 52 to perform both ends (see FIG. 4), and one end is processed with eyes. And the other end has a cut-off specification such that the winding grip 53 can be added at the site (see FIG. 5). The shock absorbing mechanism 50 is adapted to the shape of the end of each rope 2, 4, 5 The specifications are appropriately selected. Further, in the present embodiment, a wire rope having a configuration of 3 × 7φ18 is adopted as the conventional general-purpose steel rope 52, and a wire rope having a configuration of 3 × 7φ18 is adopted as the energy absorption rope 51.

  Further, the characteristics of the energy absorption rope 51 will be described. The energy absorption rope 51 has a characteristic that the longitudinal elastic modulus is smaller than that of the general-purpose steel rope 52 and the elongation near the breaking load is large.

  This characteristic is obtained by a special composition ratio of the rope. In the example filed by the present applicant, the component ratio C: 0.001% to 0.15%, Si: 0.01% to 1.5%, Mn : 0.3% to 3.0%, P: 0.05% or less, S: 0.02% or less, Cr: 14.0% to 26.0%, Ni: 86.0% to 22.0% , N: 0.02% or less, and the remainder can be obtained by drawing and twisting a steel wire consisting essentially of a soft stainless steel wire such as Fe and then heat-treating the rope with austenite.

Table 1 shows the relationship between the rope length per energy absorption rope and the energy absorption amount.
Note that the rope specifications of the test specimen are φ18 (3 × 7 SS / O), cross-sectional area A: 134 m ² , breaking load RBS: 80 kN, elastic elongation EL1: 5%, plastic elongation EL2: 15% (received collision energy) Elongation after EL1 <EL2), rope length L1: 1 to 20 m.

  Moreover, the calculation formula of energy absorption amount is derived by the following formula.

  According to the above formula, the larger the values of elastic elongation EL1 and plastic elongation EL2, the greater the amount of energy absorbed per rope. That is, it can be said that the rope material that is easy to stretch has a higher energy absorption rate.

Moreover, according to various tests, the elongation in the vicinity of the breaking load of the conventional general-purpose steel rope 52 applied to the horizontal ropes 4 and 5 and the strut retainer rope 2 remains at 3 to 5%, and the energy absorbing rope 51 on one side. The elongation in the vicinity of the breaking load is 50% or more. That is, when the energy absorbing rope 51 is pulled along with falling rocks to cause plastic deformation, collision energy several times as much as that of the conventional steel rope is absorbed.
In addition, as an energy absorption rope, the thing of another specification other than the rope of the test body shown in the said Table 1 can be used.

  Since the energy absorbing rope 51 absorbs a lot of energy in the plastic deformation region as described above, the rope easily breaks when the energy absorption amount is saturated. Therefore, in the present shock absorbing mechanism 50, a conventional general-purpose steel rope 52 is connected in parallel to the energy absorbing rope 51 with a surplus length, and even if the energy absorbing rope 51 is fully extended and broken, this conventional type The general-purpose steel rope 52 is used to connect the ropes 2, 4, 5 and the anchors together.

  As described above, the impact absorbing mechanism 50 shown in the present embodiment reaches its fracture when compared with the general-purpose steel rope 52 and the longitudinal elastic modulus which is smaller than that of the general-purpose steel rope 52 and the same length. The energy absorbing rope 51 is longer than the general-purpose steel rope 52. Further, the general-purpose steel rope 52 is bent to secure a surplus length with respect to the energy absorption rope 51, and the energy absorption rope 52 and the general-purpose steel rope 52 are connected in parallel with the surplus length secured. .

  The shock absorbing mechanism 50 as described above allows, for example, the following deformation. That is, the energy absorbing rope 51 and the versatile steel rope 52 are formed separately from each other as shown in FIG. 6 without joining them to each other. And the turnbuckle 4a may be connected. In this way, only the rope deformed by the load caused by the collision of the falling object needs to be replaced.

  The high tension wire mesh 6 as a high tension protection net is supported in the slope width direction by the ropes 2, 4 and 5 in which the shock absorbing mechanism 50 is incorporated in this way.

The high-strength wire mesh 6 is obtained by using a high-strength steel wire as a strand and processing the strand into a diamond shape. Moreover, as shown in FIG. 7, in the part 6d where the strand 6a and the strand 6b cross | intersect between the both pitches, each strand 6a, 6b cross | intersects and inscribes so that an arc may be drawn without bending.
Specifically, spiral processing is performed to draw an elliptical spiral on each strand, and the adjacent strands are knitted so that one strand is sequentially inserted between the pitches of the other strands. Similarly, another strand 6c is added in the width direction of the protective net 6 to form a net.

  In the present embodiment, a high-strength steel wire having a diameter of 3.2 to 5.0 (preferably 4.0) and a cross-sectional strength of 1400 N / mm2 is used. Further, as the mesh, a 50 mm equilateral rhombus mesh or a vertically long rhombus mesh is adopted, and the amount of processing of each strand is adjusted so that the thickness is about 20 to 30 mm.

  Further, the high-strength wire mesh 6 which is a high-strength protective mesh of this structure is compared with a conventional diamond wire mesh (galvanized wire mesh of galvanized iron wire stipulated in JIS G 3552), which is widely used as a wire mesh for rock fall protection. It has high energy absorption performance and is difficult to break. This characteristic is obtained by the interaction between the special knitting net processing described above and the high-tensile steel wire used for the wire.

  First, when an impact due to falling rocks or the like is applied to the high-tensile wire mesh 6, each strand that draws an elliptical spiral is in the long side direction of the ellipse (in the direction of arrows A and B in FIG. 7) as viewed from the direction of travel of the spiral. Absorbs collision energy while elastically deforming. That is, at the initial stage of the collision, each strand is elastically deformed in the width direction of the high-tensile wire mesh 6 while receiving a bending load at the intersection, thereby absorbing the collision energy. Subsequently, when the deformation at the intersection of each strand reaches the plastic region, each strand is bent at the intersection, and the collision energy is further absorbed by this plastic deformation. When a tensile load acts in the line direction between the intersecting points, each element wire elastically and plastically deforms in the line direction and absorbs collision energy.

  As described above, the high tension wire mesh 6 as the high tension protection mesh is not limited to deforming the wire in the direction of the wire, but is knitted so that each wire is bent at the intersection by an impact. Compared to the above, the absorbing power of collision energy is higher. Further, since the collision energy is absorbed by the deformation of each strand, the collision energy is absorbed without loss immediately after the impact action.

FIG. 8 is a load-elongation curve graph for comparing and evaluating the protective performance of the high-tensile protective net 6 having the above specifications and the conventional rhombus metal net.
In each graph, the vertical axis represents the test load (unit: N), and the horizontal axis represents the deformation (mm).
Moreover, the evaluation result of the high tension wire mesh 6 shown in the present embodiment is shown by a solid line in FIG. 8A, and the evaluation result of a conventional diamond wire mesh to be compared is shown by a solid line in FIG. 8B. Moreover, the intersection strength specimen which reproduced each wire mesh was used as a test body. In addition, the net | network specification reproduced with each test body was compared with the braided net | network of intersection angle 85 degrees (phi) 4. Moreover, the test body is shown in FIG. Each test body 60 is composed of a pair of upper and lower convex pieces 61, 61. The wire 62 is knitted between the convex pieces 61, 61 to reproduce the mesh. Further, three test bodies 60 are prepared for each protection net, and the load resistance is measured by applying a tensile load up and down by placing the test body on a testing machine.

  Moreover, the evaluation method can be grasped by comparing both graphs. In FIG. 8 (a), there is a case where the solid line is interrupted, but this is because the test body was detached from the testing machine during the test, and the test results of the high tension wire mesh 6 are the remaining two solid lines a and b. It was evaluated with.

Comparing FIG. 8A and FIG. 8B, the conventional wire mesh shown in FIG. 8B shows an elongation of about 13 mm in the vicinity of about 7000 N in each trial (solid line c). The high tension wire mesh (solid line a) shown in FIG. 2 shows an elongation of about 30 mm around 16000N.
That is, it can be said that the high tension wire mesh 6 has a large load capacity and allowance for extension, and is about twice as high as the maximum allowable load compared to the conventional diamond wire mesh.

  Next, a method for assembling the above-described high tension wire mesh 6 will be described. The high tension wire mesh 6 is assembled between the upper lateral rope 4 and the lower lateral rope 5 by using a coupling coil 16 (φ4 mm × 70 mm × 300 mm). Specifically, the high tension wire mesh 6 is covered from the slope mountain side from the upper horizontal rope 4 to the lower horizontal rope 5, and the upper coil and the lower edge of the high tension wire mesh 6 are folded back to assemble the coupling coil 16. Two coupling coils 16 are provided at the upper edge and the lower edge of the high tension wire mesh 6. Further, as shown in FIG. 1, when there is a break in the high tension wire mesh 6 between the support pillars 10, 10, the coupling coil 16 is incorporated in the longitudinal direction of the high tension wire mesh 6 to connect the wire meshes.

  Note that the support reinforcing rope 3 and the high tension wire mesh 6 arranged in the vertical direction of the support 10 are not fixed, and the high tension wire mesh 6 is flexed in the entire region without being restricted by the support reinforcing rope 3. Can be removed. That is, the high tension wire mesh 6 is provided so as to be movable with respect to the column reinforcing rope 3.

  Further, in a state where the high tension wire mesh 6 is assembled to the horizontal ropes 4, 5, a space 8 having a width of about 150 mm is secured between the high tension wire mesh 6 and the column main body portion 11. This space 8 is naturally secured by assembling the high-tension wire mesh 6 to the horizontal ropes 4 and 5 suspended on the slope mountain side of the column 10 at a position away from the column 10.

  Thus, according to the falling object protection apparatus 1 shown in the present embodiment, the space 8 is secured between the support 10 and the high-tensile wire mesh 6 by the bracket 12 protruding from the support 10 to the slope mountain side. Moreover, as the high-tensile wire mesh 6, a protective mesh with a flexible mesh structure having a high energy absorption capability is adopted. Even if the high-tensile wire mesh 6 is bent toward the slope valley side due to the collision of a falling rock, the bending Is substantially reduced by the width of the space 8 secured between the column 10 and the high tension wire mesh 6. That is, even if the energy absorbing type high tension wire mesh 6 that is easily bent is used, the column 10 can be prevented from protruding toward the inclined valley side, so that the column 10 can be installed away from the inclined surface with poor workability.

  Further, in this embodiment, the high tension wire mesh 6 is disposed on the slope mountain side where the collision between the high tension wire mesh 6 and the support column 10 is a concern, but the high tension wire mesh 6 is bent toward the support column 10 side due to falling rocks. Even so, the space 8 that can suppress the collision of the high tension wire mesh 6 is secured between the support column 10 and the high tension wire mesh 6, so that the collision is suppressed. Moreover, since it has such a structure, according to this falling object protection apparatus 1, the high tension wire mesh 6 can be addressed to the support | pillar 10 from the slope mountain side. Therefore, it is easy to secure a scaffold when assembling the high tension wire mesh 6.

  Moreover, in this Embodiment, the rigidity with respect to a broken net is improved by using a high tensile steel wire as a strand. In other words, while maintaining a flexible structure rich in energy absorption capability, the impact resistance performance of the falling object protection device is enhanced by using a net specification that is more resistant to tearing.

  Further, since the impact energy of the falling rock is absorbed not only by the energy absorbing high tension wire mesh 6 but also by the impact absorbing mechanism 50, the high tension wire mesh 6 does not protrude toward the slope valley side due to the synergistic effect.

  Further, since the energy absorbing rope 51 that absorbs the collision energy by using the deformation of the rope itself without using the friction brake is used as the shock absorbing mechanism 50, the energy of the collision immediately after the action is exerted together with the energy absorbing high tension wire mesh 6. Can be absorbed without loss. That is, since the collision energy of the falling rock can be suppressed in the initial stage of the collision with the highest energy amount, the load continuously applied to each part can be reduced at an early stage. In addition, this enables a cost-effective design in the strength design of the falling object protection device 1.

The above-described embodiment is merely an example, and the details can be changed according to various specifications.
For example, in this embodiment, the support column 10 is installed by providing the hinge 17 at the lower part of the support column 10. However, the support column 10 can also be installed using, for example, a steel pipe pile 18 embedded in the ground. In this case, for example, about 1/6 is buried in the ground from the lower end of the support column 10 as shown in FIG. The length of the lower end of the supporting pillar 10 to be embedded is not limited to the above, but specifically, the steel pipe pile 18 as a foundation is inserted deep into the ground, and then the pillar 10 is inserted into the steel pipe pile 18. The lower end is inserted, and concrete 19 is poured into the gap to fix the column 10.

  Moreover, in this Embodiment, although the overhang | projection dimension of the bracket 12 provided in the support | pillar 10 was set to 150 mm, the setting considers the scale of a fall rock, the shape of a construction place, etc., from several hundred mm to several thousand mm. The range can be changed as appropriate. In addition, the number and specifications of each rope incorporated in the fallen object protection apparatus 1 and the specifications of the high tension wire mesh 6 can be changed in consideration of the load resistance and the like.

In this embodiment, the energy absorbing rope 51 that can absorb energy without loss immediately after the impact action is used as the impact absorbing mechanism 50. Of course, even if a conventional impact absorbing mechanism using a friction brake is adopted. Good.
Moreover, in this Embodiment, although this fallen object protection apparatus 1 was provided along the lower edge (slope) of a slope, you may provide it on a slope middle. Moreover, although falling rocks have been described as an example of falling objects, the falling object protection apparatus 1 is useful for avalanches, earth and sand, and the like.

DESCRIPTION OF SYMBOLS 1 Falling object protective device 2 Prop back rope 2a Turnbuckle 3 Prop reinforcing rope 3b, 3c Eye processing part (ring-shaped end part) of prop reinforcing rope
4 Upper lateral rope 4a Turn buckle 5 Lower lateral rope 5a Turn buckle 6 High tension protective net 6a, 6b, 6c Strand 6d Strand intersection 8 Space for collision avoidance 10 Column 11 Column body 12 Bracket 13 U-shaped bolt 14 Through bolt 16 Coupling coil 17 Hinge 17a Spindle 18 Steel pipe pile 19 Concrete 50 Shock absorption mechanism 51 Energy absorption rope 52 Conventional general-purpose steel rope 53 Winding grip 60 Test piece 61 Convex piece 62 Wire 100 Falling stone protection fence 101 Post 103 Upper Support Rope 103a Brake Device 104 Lower Support Rope 104a Brake Device 105 Wire Mesh 110 Loop Pipe 111 Tightening Member

Claims (4)

A falling object protection device comprising a protective net that catches falling objects from a slope, and a support that supports the protective net,
In the protective net, each strand is formed in a spiral shape, and adjacent strands intersect without bending between both pitches,
The support is provided with a support portion that projects from the support to the slope mountain side,
The falling object protection device according to claim 1, wherein the support supports the protection net with a space on the slope mountain side through the support portion .   The fallen object protection apparatus according to claim 1, wherein the space is a space for suppressing a collision of the protective net against the support column. In order to absorb an impact acting on the horizontal rope between the horizontal rope and the anchor, the horizontal rope supporting the protective net in the slope width direction and an anchor for fixing the horizontal rope. falling objects protection device according to claim 1 or 2 of the shock-absorbing mechanism, characterized in that it is provided. The impact absorbing mechanism comprises an energy absorbing rope that has a smaller longitudinal elastic modulus than the horizontal rope and has the same length when compared to the horizontal rope, and the elongation to reach the break is longer than the horizontal rope.
The fallen object protection apparatus according to claim 3 , wherein the energy absorption rope is connected between the lateral rope and the anchor.

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