JP7202586B1 - protective fence - Google Patents

Abstract

An object of the present invention is to reduce the cost of constituent materials by reducing the load burden of posts and protective nets that constitute a protective fence while enhancing the protective performance of the protective fence. SOLUTION: This protective fence is provided with a protective net that is horizontally laid between adjacent posts 10, and the protective net is a first protective net 20 that is horizontally laid on the first slope of the posts 10, and the slope valley of the posts 10. It consists of a second protective net 30 that spans across the side of the trough so that after the first protective net 20 has finished the action of weakening the trapped object, the second protective net 30 starts the action of reducing the force of the trapped object. The relationship is such that the limit bending deformation amount of the first protective net 20 toward the side is smaller than the limit bending deformation amount of the second protective net 30 . [Selection drawing] Fig. 1

Description

The present invention captures and protects fallen objects such as fallen rocks, earth and sand, avalanches, and accumulated snow, or flying objects such as trees, destroyed buildings, and vehicles (hereinafter referred to as "captured objects") that fly due to strong winds, tornadoes, etc. The present invention relates to protective fences, and more particularly to protective fences that achieve both high performance and low cost of protective fences.

BACKGROUND ART Protective fences that trap fallen objects such as fallen rocks and earth and sand falling from slopes are widely known.
In this type of protective fence, a protective net is attached between multiple pillars set up at predetermined intervals, and when receiving an attack, the blocking surface of the protective net is plastically deformed toward the valley side of the slope to prevent falling objects. Attenuate and capture.
Various types of protective nets have been proposed, generally in the form of nets in which wire ropes and wire nets are combined.
Known forms of arranging a protective net on a support include a form in which the protective net is arranged on the slope mountain side of the support (Patent Document 1) and a form in which the protective net is arranged on the slope valley side of the support (Patent Document 1). Reference 2).
Furthermore, it is known that two sets of protective fences are installed side by side on the same slope with an interval therebetween to improve the protective performance (Patent Documents 3 and 4).

In addition, the size of the protective fence for falling rocks is increased, and the protective fence is equipped with a protective net for catching flying objects such as trees, destroyed buildings, vehicles, etc. that are blown by strong winds and tornadoes, and multiple posts that support the protective net. is also proposed.

JP 2015-81413 A JP 2014-1584 A JP-A-2001-164521 JP 2017-179999 A

The prior art described above has the following problems.
<1> In order to improve the protective performance of the protective fence, it is necessary to improve the protective performance of the protective net.
If the protective performance of the protective net is enhanced, the load bearing on the posts will increase, so the posts must be manufactured with high strength, which ultimately increases the material cost of the protective fence.
<2> Lowering the protective performance of the protective net and the posts can reduce the construction cost of the protective fence, but the protective performance of the protective fence as a whole is lowered.
Thus, conventionally, it has been difficult to achieve both high performance of the protective fence and cost reduction of the protective fence.
<3> With the protection technology for falling rocks, in which two sets of protective fences are installed side by side on the same slope with a gap between them, the overall protective performance can be improved. A lot of laying area is required to install the protective fence.

SUMMARY OF THE INVENTION An object of the present invention is to provide a protective fence capable of achieving both high performance of the protective fence and cost reduction of the protective fence.

The present invention provides a protective fence for catching an object to be captured by comprising stanchions erected at predetermined intervals so as to be able to stand on their own, and protective nets horizontally spanning between adjacent stanchions, wherein the protective nets consists of a first protective net that spans the upstream side of the adjacent struts and a second protective net that spans the downstream side of the adjacent struts, and shares the struts and has energy absorption performance on both sides of the struts. A first protective net and a second protective net of similar degree are horizontally placed so that the first protective net precedes the start time of the energy reducing action and the peak time of load bearing with respect to the second protective net, A gap is provided in advance between the first protective net and the second protective net, which are laid horizontally on both sides of the column, and the limit bending deformation amount of the first protective net toward the downstream side is the limit of the second protective net. It is smaller than the bending deformation amount.
In another aspect of the invention, the stiffness of the first protective net is greater than the stiffness of the second protective net.
In another aspect of the present invention, the first protective net comprises at least a plurality of rope members stretched between adjacent posts, and a first net integrally attached to one side of the rope member.
In another aspect of the present invention, the rope material of the first protective net is suspended between adjacent posts in a substantially figure eight shape.
In another aspect of the present invention, the rope material of the first protective net includes at least a plurality of horizontal ropes strung between adjacent struts in multiple stages.
In another aspect of the present invention, the rope material of the first protective net is a cross rope with a shock absorber that is stretched between adjacent pillars in a substantially figure-of-eight shape.
In another aspect of the present invention, a shock absorber is interposed between the ends of the rope material of the first protective net and the struts, and when a tensile force of a certain level or more acts on the rope material, the rope material Sliding occurs between the shock absorbers.
In another aspect of the present invention, a plurality of rope materials stretched between adjacent pillars of the second protective net, a shock absorber interposed in a part of the rope material, and one side of the rope material are integrated. and a second net attached to the rope material, and sliding occurs between the rope material and the shock absorber when a tensile force above a certain level acts on the rope material.
In another aspect of the present invention, the first protective net or the second protective net may be a combination of different types of protective nets having different configurations or the same type of protective nets.
In another aspect of the present invention, the second protective net is a flexible structure in which a plurality of rings are connected or a grid-like flexible structure in which wire ropes are crossed.

The present invention has at least one of the following effects.
<1> By staggering the deenergization timing of the first protective net and the second protective net, the captured object gradually collides with the first protective net and the second protective net, and the motion possessed by the captured object Energy can be efficiently attenuated.
<2> Due to the difference in the timing of functioning of the first protective net and the second protective net (starting time of energy reduction and peak time of load bearing) , the load burden on the pillars is reduced and an excessive load acts on the pillars. can be avoided.
<3> The protective fence exhibits high protective performance (buffer performance) by adding the performance of the first protective net and the second protective net, while reducing the load of the posts and the first and second protective nets that make up the protective fence. It is possible to reduce the cost of constituent materials by reducing the size.
<4> Compared to the conventional protection technology in which a plurality of guard fences are arranged at intervals, only one guard fence is required, so the installation area of the guard fence can be minimized.
<5> By reducing the load burden of the posts that make up the protective fence, it is possible to reduce the diameter of the posts and other shapes related to deformation performance, and to reduce the weight of the posts, thereby improving workability.

Assembly explanatory drawing of the protection fence of this invention which abbreviate|omitted one part Explanatory drawing of the first protective net, (A) is a side view of the protective fence as seen from the mountain side, (B) is an explanatory drawing of the cross rope that constitutes the first protective net. Explanatory diagram of the second protective net, (A) is a side view of the protective fence as seen from the valley side, (B) is an explanatory diagram of the horizontal rope that constitutes the second protective net. Plan view of protective fence with some parts omitted It is an explanatory view of the pillar with a part omitted, (A) is a perspective view of the pillar seen from the mountain side, and (B) is a perspective view of the pillar seen from the valley side. Explanatory drawing of the shock absorber, (A) is an explanatory view of a shock absorber composed of a restraint plate and a partition plate, and (B) is an explanatory view of a shock absorber composed of a base plate and a restraint plate. Explanatory diagrams of the force-absorbing action of the first protective net, (A) is a side model diagram of the first protective net, (B) is a cross-sectional model diagram of the first protective net. Explanatory diagrams of the force-absorbing action of the second protective net, (A) is a side model diagram of the second protective net, (B) is a cross-sectional model diagram of the second protective net. Explanatory diagram of the relationship between the load and displacement of the first and second guard fences constituting the guard fence and the relationship between the reaction force of the support, (A) is an explanatory diagram of the load and displacement of the first guard fence, (B) is Explanatory diagram of the load and displacement of the second protective fence, (C) is an explanatory diagram of the reaction force of the support Explanatory drawing of another protective net according to the third embodiment

[Example 1]
1. Objects to be Captured Objects to be captured by the protective fence according to the present invention refer to objects to be captured including collapsing objects or flying objects.
Collapsed objects include falling rocks, earth and sand, avalanches, and accumulated snow that collapse along slopes. Flying objects include trees blown by strong winds, typhoons, tornadoes, etc., and structural members of destroyed buildings and vehicles. .

2. Overview of protective fences Protective fences for falling objects and protective fences for flying objects have the same basic structure, except for the dimensions of the fence itself.
In this example, a guard fence for falling objects will be explained.

1 to 5, the protective fence consists of a plurality of struts 10 that are self-supportingly erected at predetermined intervals, and on the slope mountain side (upstream side or one side side) of the plurality of struts 10. It comprises a first protective net that is laid horizontally, and a second protective net 30 that is laid horizontally on the slope valley side (downstream side or the other side surface side) of the plurality of columns 10 .

Between the heads of the adjacent struts 10, rod-shaped spacing members 12 are laid horizontally.
The head of the strut 10 and the end of the spacing member 12 are movably connected via a universal hinge mechanism having a vertical spindle and a horizontal spindle.

3. Column Description will be made with reference to FIG. The struts 10 are classified into terminal struts and intermediate struts according to their positions, but have the same basic structure.

The strut 10 has a strut body 11 . As for the erecting form of the column 10, in addition to the form in which the lower part of the column body 11 is buried in the foundation and the column 10 is erected, the lower end surface of the column body 11 is the foundation surface (the surface of the local ground, the concrete foundation) It may be set up by landing on the top surface, etc.).

<1> Support Body The support body 11 illustrated in FIGS. 4 and 5 will be described.
The column body 11 is a concrete-filled steel pipe, and is manufactured by arranging a plurality of reinforcing members 14 in parallel inside a steel pipe 13 and then filling it with concrete 15 .
The support 10 made of concrete-filled steel pipe can exhibit high toughness with a simple structure.
The column body 11 may be a concrete-filled steel pipe with the reinforcing member 13 omitted.

<2> Mooring Elements and Brackets Mooring elements 16 , 16 for mooring the cross ropes 21 constituting the first protective net 20 protrude from the top and bottom of the mountain-side peripheral surface of the column body 11 .
Brackets 17 , 17 for connecting the horizontal ropes 31 constituting the second protective net 30 are projected from the upper and lower portions of the valley-side peripheral surface of the support body 11 .

<2.1> Mooring element The mooring element 16 of the strut 10 illustrated in FIGS. 4 and 5 is a member for commonly winding two sets of adjacent cross ropes 21 , 21 .

The mooring element 16 of this example includes a short post 16a horizontally projecting from the outer peripheral surface of the post 10, and one or more detents 16b installed across the short post 16a and the post body 11.
The outer peripheral surface of the short pillar 16a is formed into an arcuate surface to reduce the sliding resistance between the cross rope 21 of the first protective net 20 and the short pillar 16a.

Other mooring elements 16 include a configuration in which the stopper 13 is omitted and a guide groove capable of accommodating the cross rope 30 is formed on the outer peripheral surface of the short post 16a, or a rotatable double pulley instead of the short post 16a. A pivotal configuration is also possible.

<2.2> Bracket The bracket 17 illustrated in FIGS.
The bracket 17 has a plurality of mounting holes 17a on its plate surface, and is fixed to the valley side outer peripheral surface of the column body 11 by welding or the like.
The ends of split ropes 31a constituting each horizontal rope 31 are connected to the mounting holes 17a of the bracket 17 via shackles 34. As shown in FIG.

4. Protective Net The protective fence of the present invention comprises two protective nets, a first protective net 20 made of metal or fiber and a second protective net 30 made of metal or fiber, with a support 10 sandwiched between them. .
The first protective net 20 and the second protective net 30 have different limit bending deformation amounts, and the first protective net 20 has a smaller bending deformation limit than the second protective net 30 .

<1> First protective net The first protective net 20 exemplified in this example is provided between the upper and lower portions of the mountain-side peripheral surfaces of the adjacent columns 10, 10, and intersects and continues vertically and obliquely in a substantially figure eight shape. It comprises a passed cross rope 21 and a first net 23 arranged so as to overlap with the cross rope 21.例文帳に追加
The cross rope 21 and the first net 23 are integrally connected by a known connecting coil or the like.

<1.1> Cross Rope The cross rope 21 comprises a plurality of split ropes 21a, 21b and shock absorbers 22, 22 that grip overlapping portions near ends of the split ropes 21a, 21b.

The split ropes 21a and 21b have a sliding length (slip length) over the entire length that can be spanned between the upper and lower portions of the adjacent struts 10 and 10, and between the upper and lower portions of the adjacent struts 10 and 10, and across the entire length that can be continuously and diagonally crossed in a substantially figure eight shape. It has the total length including the long portion 21c.

To explain the method of assembling the cross rope 21, part of the split rope 21a in the upper half is stretched between the upper parts of the mountain-side peripheral surfaces of the supports 10, 10, and part of the split rope 21b in the lower half is attached to the supports 10, 10. It spans between the lower part of the mountain side peripheral surface of
The overlapped portions of the divided ropes 21a and 21b near their ends are gripped by a friction-sliding shock absorber 22 and stretched in a figure-of-eight shape.

<1.2> Surplus Length of Cross Rope Parts of the split ropes 21a and 21b protruding outward from the shock absorber 22 serve as surplus lengths 21c.
The cross rope 21 exerts a kinetic energy absorbing action (buffering action) of the object to be caught by the sliding movement of the surplus length portion 21c gripped by the buffer device 22. As shown in FIG.
When the surplus length portion 21c disappears and the cushioning effect of the cushioning device 22 is terminated, the cushioning effect of the cross rope 21 is terminated.
Therefore, the total length of the surplus length portion 21c of the cross rope 21 is appropriately selected according to the cushioning performance of the first protective net 20 and the like.

<1.3> Reasons why the cross ropes are laid in a figure-eight shape , to suppress deformation in the height direction of the first protective net 20 .

<2> Second protection net The second protection net 30 exemplified in the present example includes horizontal ropes 31, 31 horizontally suspended between the upper and lower portions of the valley-side peripheral surfaces of the adjacent struts 10, 10, and horizontal ropes 31, 31 It comprises a rope 31 and a second net 33 arranged so as to overlap.
The upper and lower horizontal ropes 31, 31 and the second net 33 are integrally connected by a known connecting coil or the like.

<2.1> Horizontal Rope The horizontal rope 31 comprises a plurality of split ropes 31a, 31a and a shock absorber 32 that grips overlapping portions near ends of the split ropes 31a, 31a.
The split rope 31a that constitutes the horizontal rope 31 has an extra length that is a sliding length (slip length) over the entire length that can be continuously spanned between the upper and lower portions of the valley-side peripheral surfaces of the adjacent struts 10, 10. It has the total length including the portion 31c.

<2.2> Excess portion of horizontal rope Each horizontal rope 31 has its end connected to the bracket 17 of the support 10 via the shackle 34, and the ends of the split ropes 31a, 31a are overlapped. The part is gripped by a friction-sliding shock absorber 32 .
The portion of the split rope 31a that extends outward from the shock absorber 32 serves as an extra length portion 31c.

The sliding motion between the horizontal rope 31 and the buffer device 32 exerts a function of absorbing (buffering) the kinetic energy of the captured object, and the buffering function ends when the excess length 31c disappears.
Therefore, the dimension of the extra length portion 31c of the horizontal rope 31 is appropriately selected according to the cushioning performance of the second protective net 30 and the like.

<3> Shock Absorber As the shock absorbers 22 and 33, known friction sliding shock absorbers or shock absorbers are applicable.

<3.1> Example of shock absorber (1)
The shock absorbers 40 and 50 illustrated in FIG. 6 will be described.
The shock absorber 40 illustrated in FIG. 6(A) includes a restraining plate 41 formed by folding the center of the spring plate to form an expanded portion 42 and a rope accommodation space formed in the expanded portion 42 of the constraining plate 41. It consists of a plurality of partition plates 43, and bolts 44 and nuts 45 for tightening the expanded portion 42 of the restraint plate 41 in the direction of contraction.
The extended portion 42 of the restraining plate 41 restrains the overlapping portion of the two ropes 21a, 21b (31a, 31a) accommodated in the extended portion 42. As shown in FIG.

The tensile force acting on the ropes exceeds the frictional resistance between the ropes 21a, 21b (31a, 31a) and the shock absorber 40, causing sliding between the ropes 21a, 21b (31a, 31a) and the shock absorber 40. .

<3.2> Example of shock absorber (2)
The shock absorber 50 illustrated in FIG. 6(B) has a flat substrate 51 and an accommodation groove 53 arranged opposite the substrate 51 and capable of accommodating the respective ropes 21a, 21b (31a, 31a) on the plate surface. and a bolt 54 and a nut 55 for tightening between the substrates 51 , 52 and the restraining plate 52 .
Both ends of the accommodation groove 53 are tapered from the inside to the outside.
The overlapping portions of the two ropes 21a, 21b (31a, 31a) housed in the housing groove 53 are restrained by the tightening force of the bolts 54 and nuts 55. As shown in FIG.

The tensile force acting on the ropes exceeds the frictional resistance between the ropes 21a, 21b (31a, 31a) and the shock absorber 50, causing sliding between the ropes 21a, 21b (31a, 31a) and the shock absorber 50.

<4> Net The first protective net 20 has a first net 23 and the second protective net 30 has a second net 33 .
For each of the first and second nets 23, 33, a known rhombic wire mesh knitted from steel wires or high-strength steel wires can be applied.
The first net 23 is integrated with the cross ropes 21 via a known connecting coil or the like, and load transmission between the first net 23 and the cross ropes 21 is possible.
Similarly, the second net 33 is integrated with the horizontal rope 31 via a known connecting coil or the like, and load transmission between the second net 33 and the horizontal rope 31 is possible.

<5> Reasons why protective nets are provided on both sides of the pillar In the protective fence according to the present invention, two protective nets, the first protective net 20 and the second protective net 30, are arranged with the pillar 10 interposed therebetween. The limit bending deformation amount of the first protection net 20 is made smaller than the limit bending deformation amount of the second protection net 30. - 特許庁
The reason why the protective fence of the present invention is constructed in this way is that the kinetic energy of the captured object is dispersed and absorbed by the respective protective nets 20 and 30 to improve the protective performance (buffer performance). This is to reduce the load burden of the supporting column 10 and the protective nets 20, 30, thereby reducing the cost of the constituent materials.

5. Protective Fence Construction Method The protective fence construction method will be described with reference to FIGS.

<1> Erecting of struts A plurality of struts 10 are erected in the middle of the slope or at the foot of the slope at predetermined intervals, and a spacing member 12 is placed horizontally between the heads of the adjacent struts 10, 10. Hang.

<2> Attachment of first protective net and second protective net The first protective net 20 is attached to the mountain side of the adjacent struts 10, and the second protective net 30 is attached to the valley side of the adjacent struts 10 to construct the protective fence. to complete.
The first protective net 20 and the second protective net 30 can be efficiently attached by carrying out the work in parallel on the mountain side and the valley side for the same post 10.例文帳に追加

6. Energy-reducing action of the protective fence The energy-reducing action of the protective fence will be described with reference to FIGS. 7 to 9. FIG.

<1> Energy-reducing action by the first protective net FIG. 7 shows a model diagram of the protective fence when the first protective net 20 receives an attack.
FIG. 7A shows a model side view of the first protection net 20 viewed from the mountain side to the valley side, and FIG. 7B shows a cross-sectional model view of the first protection net 20 alone.

When a captured object F such as a falling rock falls from the sloped mountain side of the protective fence, the captured object F collides with the first protective net 20 positioned on the mountain side of the support 10 .
The impact acting on the first protection net 20 is supported by the struts 10 through the first protection net 20 .

As the captured object F collides, the first protective net 20 deforms toward the trough side of the slope.
The first net 23 also follows the cross rope 21 and deforms toward the slope valley side.

When the tensile force acting on the cross rope 21 exceeds the frictional resistance of the shock absorber 22, the cross rope 21 constituting the first protective net 20 slides between the shock absorber 22 and the cross rope 21 and is captured. Absorb the kinetic energy of the object F.

If the kinetic energy of the captured object F is within the range of the buffering performance of the first protective net 20, the first protective net 20 alone absorbs all of the kinetic energy possessed by the captured object F.

<2> Energy reducing action by the second protective net FIG. 8 shows a model diagram of the protective fence when the second protective net 30 receives an attack.
FIG. 8A shows a side model view of the second protection net 30 viewed from the mountain side to the valley side, and FIG. 8B shows a cross-sectional model view of the second protection net 30 alone.

Immediately before the first protection net 20 shown in FIG. 7 reaches the limit deflection amount or when it reaches the limit deflection amount, the captured object F collides with the second protection net 30 and the second protection net 30 is weakened. It exerts its action (protective action).

As shown in FIG. 8, when the object to be caught F collides, the second net 32 and the horizontal rope 31 forming the second protective net 30 are deformed toward the valley side.
When the tensile force acting on the horizontal rope 31 exceeds the frictional resistance of the shock absorber 32, sliding occurs between the shock absorber 32 and the horizontal rope 31 to absorb the kinetic energy.
The support column 10 continues to support the impact acting on the second protective net 30 .

<3> Comprehensive force-reducing action by both protective nets As described above, in the present invention, the first protective net 20 exerts its force-reducing action first, and the force-reducing action of the first protective net 20 begins to decline. At times, the second protective net 30 exerts a force-reducing effect.
In other words, the load bearing peaks of the two protective nets 20 and 30 do not overlap, and the second protective net 30 reaches its peak after the first protective net 20 passes its peak.

The reason why the peaks of the first protective net 20 and the second protective net 30 are deviated is that while the load on the column 10 is reduced, the first and second protective nets 20 and 30 continue to function to absorb energy. This is to secure a longer time and increase the amount of energy absorbed by the protective fence as a whole.

As a comparison, a protective fence with a single protective net is assumed.
In the case of a proportional protective fence, for example, in order to demonstrate the performance of 300kJ, it is necessary to use high-strength materials that can support the energy of 300kJ for the rope materials and net materials that make up the protective net, and furthermore, the struts must also be 300kJ. of energy must be designed to be strong enough to support it, and the material cost is much higher in contrasting protective fences.

On the other hand, in the protective fence of the present invention, when the first protective net 20 having an energy absorption performance of, for example, 150 kJ and the second protective net 30 having an energy absorption performance of 150 kJ are combined, the first and second protective nets The total energy absorption performance of 20 and 30 is 300 kJ, which is a high cushioning performance.

<4> Relationship between received load of first and second protective nets and reaction force of support column Referring to FIG. explain.

<4.1> Change in Load of First Protection Net FIG. 9A shows the relationship between the change in load and the amount of deformation of the first protection net 20 when receiving an attack.
The load on the first protective net 20 increases rapidly while deforming at the moment when the captured object F collides with the first protective net 20, and after the peak, the load burden gradually decreases.
When the deformation of the first protection net 20 reaches the limit bending deformation amount, the load bearing of the first protection net 20 disappears.

<4.2> Change in Load of Second Protection Net FIG. 9B shows the relationship between the change in load and the amount of deformation of the second protection net 20 when receiving an attack.
When the first protective net 20 has passed the load peak, the second protective net 30 starts to deform little by little and the burden load gradually increases.
In the process in which the load borne by the second protective net 30 increases, the load borne by the first protective net 20 disappears and the load is borne by the second protective net 30 alone.

<4.3> Change in reaction force of strut FIG. 9C shows the change in reaction force of the strut 10 when receiving an attack with a broken line.
Not only in sections where the first or second protective nets 20, 30 function individually, but also in sections where the first and second protective nets 20, 30 function simultaneously, the reaction force of the pillars 10 is , is less than the peak load of both protective nets 20,30.
Therefore, even if the first and second protective nets 20 and 30 are provided on the common support 10, no excessive reaction force is generated on the support 10 when receiving an attack.

<5> Method for Adjusting the Critical Bending Deformation Amount of the First Protective Net The first protective net 20 has a smaller critical flexural deformation amount than the second protective net 30 .
The limit bending deformation amount of the first protection net 20 can be adjusted by changing the deformation amount of the cross ropes 21 of the first protection net 20 .
In this example, by setting the total length of the surplus length portion 21c constituting the cross rope 21 of the first protection net 20 short, or by setting the breaking strength of the cross rope 21 to be smaller than that of the horizontal rope 31, the first protection The limit bending deformation amount of the net 20 can be adjusted.

7. Relationship Between First Protective Net and Second Protective Net As described above, the first protective net 20 and the second protective net 30 each exhibit a kinetic energy absorption function, but the deformation performance that exhibits this function different time zones.
The different deformation performance includes the limit bending deformation amount of the protective net, the degree of rigidity of the protective net, the amount of energy absorption, the necessity of a shock absorber, the type of suitable load, etc., and will be described in detail below.

<1> Critical Bending Deformation Amount of Protective Net As described above, the first and second protective nets 20 and 30 have different critical flexural deformation amounts, and the first protective net 20 has a limit flexural deformation amount equal to that of the second protective net. It is smaller than the limit bending deformation amount of 30.
The reason why the limit flexural deformation amount of the first protective net 20 is reduced is to absorb kinetic energy with a small deformation.
The reason why the limit bending deformation amount of the second protective net 20 is increased is to ensure a long absorption time of kinetic energy.

<2> Rigidity of Protective Net The first and second protective nets 20 and 30 differ in the rigidity of the receiving surface.
The first protective net 20 has a structure with high rigidity so that it can receive the load in a short period of time, while the second protective net 30 has a structure with low rigidity so as to ensure a long receiving time. It is a body (flexible structure).

<3> Amount of Kinetic Energy Absorption The first and second protective nets 20 and 30 have different kinetic energy absorption amounts, and the second protective net 30 has a larger energy absorption amount than the first protective net 20 . .
This is because the amount of deformation of the second protective net 30 is larger than the amount of deformation of the first protective net 20 .

<4> Necessity of Shock Absorber The first and second protective nets 20 and 30 differ in the presence or absence of a shock absorber.
In this example, a form in which the shock absorbers 22 and 32 are arranged in the first and second protective nets 20 and 30 has been described. The damping device 32 is essential for the large second protective net 30 .

<5> Types of Suitable Loads The first protective net 20 functions effectively even against dynamic loads acting on points such as falling rocks. It functions more effectively against a static load or the like that acts on the surface.

On the other hand, the second protective net 30 is constructed so as to function effectively against a dynamic load acting pointwise against the blocking surface, such as falling rocks.

<6> Functional Time Zone The first and second protective nets 20 and 30 have different functional time zones.
In other words, the load bearing peaks of the protective nets 20 and 30 fluctuate.
The first protective net 20 functions alone, and the second protective net 30 functions when the protective function of the first protective net 20 is lowered.

8. When the object to be captured is a flying object <1> Construction of the protective fence Although the case in which the object to be captured is a collapsing object has been described above, even in the case where the object to be captured is a flying object, the overall dimensions are different. , the basic configuration of the protective fence is the same as the configuration described above.

<2> Installation location of protective fences Protective fences shall be erected near objects to be protected that require protection from flying objects.
For example, when protecting a containment building containing power generation equipment, a protective fence is installed over an area that requires protection, such as the perimeter of the containment building.
The size of the protective fence is selected appropriately according to the protection range.
When installing the protective fence, the first protective net 20 is arranged with respect to the support 10 so as to face the flying direction (upstream side) of the flying object.

<3> Energy-reducing action of protective fence Since the energy-reducing action of the flying object by the protective fence is as described above, its explanation is omitted.

<4> Effect According to the present invention, even if the object to be captured is a flying object, the protective fence can catch the flying object or attenuate the kinetic energy of the flying object to safely protect the object to be protected.

[Example 2]
Other embodiments will be described below. In the description, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

<1> Combination of Homogeneous Protective Nets In the first embodiment, the configuration in which the first protective net 20 and the second protective net 30 are configured by a combination of different types of protective nets having different configurations has been described. Not limited to combinations.

The first and second protective nets 20, 30 may be a combination of similar protective nets.
That is, the first and second protection nets 20 and 30 may be composed of the protection nets provided with the cross ropes 21 and net materials shown in FIG. 2, or the protection nets provided with the horizontal ropes 31 and net materials shown in FIG. Configure with net.

In the case of this example as well, the limit bending deformation amount of the first protective net 20 is made smaller than the limit bending deformation amount of the second protective net 30, as in the first embodiment.
For example, when a protective net of the same type is attached between the pillars 10, slack occurs. 2. A difference can be provided in the limit flexural deformation amounts of the protective nets 20 and 30 .

<2> Effects of this example In this example, the same effects as those of the first embodiment described above are obtained.
Especially in this example, since the constituent materials of the first and second protective nets 20 and 30 are common, material management is facilitated.

[Example 3]
The first protective net 20 and the second protective net 30 are not limited to the forms described above.
Protective nets applicable to the first protective net 20 or the second protective net 30 will be described with reference to FIGS.

<1> Protective net example 1 (Fig. 10(A))
The protective net 60A of this example has a configuration in which two sets of cross ropes 21, 21 having a figure-of-eight shape on one side (upstream side or downstream side) of the adjacent struts 10, 10 and equipped with shock absorbers are arranged in two upper and lower stages. indicates

<2> Protective net example 2 (Fig. 10(B))
The protection net 60B of this example shows a configuration in which a plurality of horizontal ropes 63 are arranged in multiple stages between the adjacent struts 10,10.
In this example, shock absorbers 64 are interposed between both ends of each horizontal rope 63 and the strut 10 .
Both ends of each horizontal rope 63 are provided with extra lengths extending from the shock absorbers 64 .

<3> Protective net example 3 (Fig. 10(C))
The protection net 60C of this example shows a configuration in which a plurality of horizontal ropes 63 are arranged in multiple stages between adjacent struts 10,10.
In this example, the both ends of each horizontal rope 63 are directly connected to the struts 10 without a shock absorber.

<4> Protective net example 4 (Fig. 10(D))
The protective net 60D of this example shows a configuration in which a plurality of rings 65 are continuously formed between adjacent struts 10, 10 to form blocking surfaces.
That is, the blocking surface is configured by a connected body of a plurality of rings 65 .
The ring 65 is made of steel wire or wire rope.
The protective net 60D of this example does not have a shock absorber.

<5> Protective net example 5 (Fig. 10(E))
The protective net 60E of this example shows a form in which wire ropes are crossed between adjacent struts 10, 10 to form a grid-like blocking surface.
The protective net 60E of this example does not have a shock absorber.

<6> Rigidity of Protective Net The illustrated protective nets 60A to 60C have relatively high rigidity and a small amount of deformation.
More specifically, the rigidity increases and the amount of deformation decreases from the protection net 60A to the protection net 60C.

The protective nets 60A, 60B can be used as either the first protective net 20 or the second protective net 30. FIG.

The protective net 60C having the highest rigidity is suitable for use as the first protective net 20. FIG.

The protection nets 60D and 60E are nets of flexible structures with a relatively large amount of deformation.
The protective nets 60D, 60E are preferably used for the second protective net 30. FIG.

<7> Effects of this example In this example, the same effects as those of the first embodiment described above are obtained.
Particularly in this example, the optimum combination of the first protective net 20 and the second protective net 30 can be selected for the site by considering the magnitude of the impact force, the allowable amount of deformation of the protective net at the installation site, and the like.

Reference Signs List 10: Strut 11: Strut body 12: Spacing member 13: Steel pipe 14: Reinforcement member 15: Concrete 16: Mooring element 17: Bracket 20 First protective net 21 Cross rope 21 a Divided rope 21 b Divided rope 21 c Excess portion 22 Shock absorber 23 First net 30 Second protection net 31 Horizontal rope 31a Divided rope 31c Excess portion 32 Shock absorber 33 Second net 40 .. Shock absorber 50 .. Shock absorber 60A to 60F .. Other protective net F .. Captured object

Claims (11)

A protective fence for catching an object to be caught by comprising stanchions erected at predetermined intervals so as to be able to stand on their own and protective nets horizontally spanning between adjacent stanchions,
a first protective net that spans across the upstream side of the struts adjacent to the protective net;
Consisting of a second protective net that spans the downstream side of the adjacent struts,
A first protective net and a second protective net having substantially the same energy absorption performance are horizontally installed on both sides of the support while sharing the support,
Said first protective net and second protective net are laid across both sides of said column so that said first protective net precedes said second protective net in the start time of the force reducing action and the peak time of load bearing. A space is provided in advance between the
protective fence. The protective fence according to claim 1, characterized in that the rigidity of said first protective net is greater than that of said second protective net. 3. The protective net according to claim 1 or 2, wherein the first protective net comprises at least a plurality of rope materials stretched between adjacent pillars and a first net integrally attached to one side of the rope material. Protective fence as described. 3. The protective fence according to claim 1 or 2, wherein the rope material of said first protective net is a cross rope with a shock absorber that is stretched between adjacent pillars in a figure-of-eight shape. 3. The protective fence according to claim 1 or 2, wherein the rope material of said first protective net includes at least a plurality of horizontal ropes suspended in multiple stages between adjacent posts. A cushioning device is interposed in a part of the rope material of the first protective net, and sliding occurs between the rope material and the cushioning device when a tensile force above a certain level acts on the rope material. The protective fence according to claim 5, wherein a plurality of rope materials that the second protective net spans between adjacent pillars, a shock absorber interposed in a part of the rope material, and a second net that is integrally attached to one side of the rope material; , wherein sliding occurs between the rope material and the shock absorber when a tensile force above a certain level acts on the rope material. 3. The protective fence according to claim 1, wherein said second protective net is a flexible structure formed by connecting a plurality of rings. 3. The protective fence according to claim 1 or 2, wherein said second protective net is a grid-like flexible structure in which wire ropes are crossed. 3. The protective fence according to claim 1 or 2, wherein the first protective net and the second protective net are a combination of protective nets of different types or of the same type. 3. The protective fence according to claim 1 or 2, wherein said captured object is a collapsing object or a flying object.

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