JP6518849B1 - Guard fence - Google Patents

Abstract

An object of the present invention is to provide a combined protection fence which functions effectively with respect to a dynamic load and a static load by enhancing the load distribution to the material of the protection fence. SOLUTION: A plurality of end cross ropes 21 having a plurality of support columns 10 and a protective net 20, the protective net 20 being spanwise spanned between adjacent support columns, and a plurality of support columns 10 The intermediate lateral rope 23 and ropes are composed of a plurality of intermediate lateral ropes 23 which are laid in multiple stages, a shock absorber 30 interposed between the end of each intermediate lateral rope and a terminal support, and a plurality of rope nets 23 While fixing between the nets 24 and connecting the upper and lower sides of the rope net 24 to the end lateral ropes 21 and 22, the load between the intermediate lateral rope 23 and the rope net 24 and the end lateral ropes 21 and 22 Made it possible to communicate. [Selected figure] Figure 1

Description

  The present invention relates to a guard fence erected on a slope or slope foot of a hillside, and is particularly effective against both dynamic load such as falling rock and static load such as snow load, and economically It relates to a combined protective fence.

A guard fence provided with a support and a guard net is well known, and various guard nets have been proposed variously depending on the performance of a hit and the like.
In general, conventional protective nets are roughly divided into the following two from their variations.
Type 1) Plastically deformable rope net provided with a shock absorber (Patent Documents 1 to 3).
Type 2) A rope net that can be elastically deformed without including a shock absorber (Patent Documents 4 and 5).

  In the past, dual-purpose guard fences that can counter static as well as dynamic loads have been commercialized, but in the actual design of protective nets, they function effectively mainly for dynamic loads. It is designed to give priority to either Type 1 or Type 2 that works effectively for static loads.

JP 2002-54109 A JP 2003-34912 A JP, 2014-1584, A Japanese Patent Application Laid-Open No. 2003-314092 JP 2005-213747 A

The conventional combined protection fence has the following problems to be solved.
<1> Guard fences giving priority to dynamic loads have low performance against static loads, and guard fences giving priority to static loads have low performance against dynamic loads. The difference appeared to be large.
Therefore, it is awaited to propose a protective fence that works equally well not only with dynamic loads but also with static loads.
<2> The conventional protection fences are designed so that various materials such as columns and ropes that constitute the protection fence can withstand the maximum load because the load transfer route is not specified.
Therefore, the entire fence tends to be over-designed, which not only raises the problem of high cost, but also involves the problem of deterioration in handling due to the increase in weight.
<3> The conventional protection fence was the idea of bearing the load which finally acted on the protection net by the strength of the support regardless of the load type.
Therefore, among the constituent materials of the protective fence, the intermediate support and the terminal support tend to be overdesigned from the viewpoint of securing the strength.

The present invention has been made to solve the above problems, and an object of the present invention is to provide the following protective fence.
<1> To effectively function not only for dynamic load but also for static load, and the performance difference by load type is small.
<2> Distribute and effectively dampen the load to all the components of the guard fence.
<3> To be able to economically manufacture guard fences by avoiding overdesign of each component material.

The present invention is a guard fence having a plurality of struts and a guard net stretched between the struts, wherein the guard net is spanned across the upper and lower ends of the adjacent struts. The intermediate lateral ropes are interposed between the ends of the intermediate lateral ropes and the end struts to hold the intermediate lateral ropes in a slippable manner. Shock absorber, and a rope net arranged to cover a plurality of intermediate horizontal ropes, and the plurality of intermediate horizontal ropes, the rope net and the end horizontal rope can transmit the load to one another. The middle horizontal rope and the rope net are fixed, and the upper and lower sides of the rope net are connected to the end horizontal rope.
According to the present invention, the load dispersed in each component of the guard fence can be effectively damped, and the present invention can effectively function not only dynamic load but also static load.
In another embodiment of the present invention, the slip initiation force of the shock absorber is set smaller than the tensile strength of the rope net, the intermediate cross ropes, and the end cross ropes.
In another embodiment of the present invention, the slip initiation force of the shock absorber, the tensile strength of the rope net, the tensile strength of the intermediate transverse rope, the tensile strength of the end transverse rope, and the flexural strength of the strut satisfy the following relationship (1) Is set as.

f ₁ <σ ₁ ≦ σ ₂ σσ ₃ <σ ₄ (1)
f _1: the slip start force shock absorber sigma _1: Tensile strength of the rope net sigma _2: Tensile strength of the intermediate horizontal rope sigma _3: end transverse tensile strength of the rope sigma _4: flexural strength of the post

  In another embodiment of the present invention, the slip initiation force of the shock absorber, the tensile strength of the end lateral rope, and the flexural strength of the support are set to satisfy the following relational expression (2).

Σσ ₄ <((σ ₃ + f ₁ ) (2)

In another aspect of the present invention, the rope nets are independent in span units of a support.
In another aspect of the present invention, upper and lower sides of the rope net are anchored so as to be slidable laterally with respect to end lateral ropes.
In another embodiment of the present invention, the rope net may be either a mesh net or a ring net.
In another embodiment of the present invention, a mesh material may be disposed so as to be polymerized on the surface of the rope net.

The present invention has the following effects.
<1> Since it is possible to transmit the load among all the constituent materials (rope net, middle horizontal rope, end horizontal rope, column) that composes the protection fence, it works on a part of the protection net Load can be dispersed widely and effectively damped.
<2> The load transfer route of the guard fence is the same whether the load is dynamic load or static load, so it works effectively for dynamic load and static load, and the performance difference by load type is It becomes smaller.
<3> The shock absorber exhibits not only a shock absorbing function but also a fuse function to prevent breakage of the rope material constituting the protective net.
Therefore, the protective fence can be economically manufactured by avoiding the overdesign of each component of the protective fence.

Front view of a protective fence according to the present invention in which a part is omitted Perspective view of end side rope An illustration of the mounting structure of the adjacent rope nets and the intermediate column An illustration of the installation structure of the terminal post and the intermediate horizontal rope with a part omitted Explanatory drawing of mooring structure of rope net and end side rope which omitted a part Model diagram of the guard fence to explain the transfer route of dynamic load and static load

  The invention will now be described with reference to the drawings.

<1> Outline of Guard Fence Referring to FIG. 1, the present invention is a guard fence provided with a plurality of pillars 10 erected at a predetermined distance and a guard net 20 stretched between the pillars 10. It is assumed that the load distribution of each material constituting the guard fence is promoted to effectively function not only the dynamic load but also the static load. Hereinafter, each constituent material of the guard fence concerning the present invention is explained in full detail.

<2> Support (intermediate support, terminal support)
The column 10 is composed of an intermediate column 10a and a terminal column 10b, and can be a steel material such as a known shaped steel or steel pipe, a concrete column, or a filled steel pipe in which a steel pipe and concrete are combined.
With regard to the erected form of the support 10, the lower portion of the support 10 may be erected on the support structure 11 such as a concrete foundation so as not to be inclinable, or may be erected on the local ground.
Moreover, although illustration is abbreviate | omitted, you may make it support on the stay rope connected with the mountain side anchor the head of each support | pillar 10. As shown in FIG. In this case, a shock absorber may be interposed in a part of the stay rope.

In FIG. 1, reference numeral 28 denotes a support spacing rope connected between the heads of the adjacent supports 10, which functions to keep the spacing between the supports 10 constant when the supports 10 are erected.
It is also possible to substitute the upper end lateral rope 21 instead of the supporting rod spacing rope 28 as an essential component.

<3> Protective Nets The protective nets 20 include end lateral ropes 21 and 22 spanned in span units between upper and lower portions of adjacent struts 10 and a plurality of transversely extended struts 10 between upper and lower portions of the struts 10. A middle horizontal rope 23, a shock absorber 30 interposed between an end of each middle horizontal rope 23 and a terminal support 10b, a rope net 24 arranged to cover a plurality of middle horizontal ropes 23, and a rope net 24 and a mesh material 25 which is arranged by polymerization.

<3.1> End lateral ropes The end lateral ropes 21 and 22 consist of one or more independent rope materials stretched between the adjacent columns 10, and can extend across the adjacent columns 10 ((1) 1 span length).
The end lateral ropes 21 and 22 have a function as a load transfer member between the adjacent columns 10 and a function as a support member for the upper and lower sides of the rope net 24.
Both ends of each end lateral ropes 21 and 22 are directly connected to the column 10, and no shock absorber is provided.

  In the end lateral ropes 21 and 22 illustrated in FIG. 2, the end lateral ropes 21 and 22 have a loop 21 c formed at one end (left) in advance, and a loop 21 d at the other end (right) The wire clip is used to form a loop at the site.

<3.2> Middle horizontal ropes A plurality of middle horizontal ropes 23 is a rope material having an overall length that can be straddled over a plurality of columns 10, and is attached to the mountain sides of the columns 10 at predetermined intervals at multiple intervals. is there.

  As described with reference to FIG. 3, the intermediate lateral rope 23 is anchored to a hook 12 or the like provided on the circumferential surface of the intermediate support 10 a so that the intermediate lateral rope 23 does not fall off under its own weight.

Each intermediate horizontal rope 23 has a shock absorber 30 at a part thereof.
As described with reference to FIG. 4, a shock absorber 30 is attached near the end of each intermediate horizontal rope 23 and is connected to the end post 10 b via the shock absorber 30.
In order to allow slippage of the intermediate lateral ropes 23, each intermediate lateral rope 23 is formed with a surplus length portion 23a of an appropriate length in a range extending outward from the shock absorber 30.

<3.3> Shock Absorber Referring to the friction slide type shock absorber 30 illustrated in FIG. 4, the shock absorber 30 supports the gripping means 31 such as a wire clip capable of gripping the intermediate horizontal rope 23 and the gripping means 31. And a U-shaped connecting bolt 33 for connecting the supporting plate 32 to the side surface of the end post 10b.
A plurality of holes are opened in the plate surface of the bearing plate 32, and the intermediate horizontal rope 23 and the connection bolt 33 can be inserted into the bearing plate 32 through these holes.
The shock absorbing device 30 is not limited to the frictional sliding type, and any known shock absorbing device can be applied as long as it is a structure that can exert a shock absorbing function when tension above a certain level acts on the intermediate horizontal rope 23.

<3.4> Rope Netting Referring to FIG. 1, the rope net 24 has a function of catching falling objects in cooperation with a plurality of intermediate horizontal ropes 23, a function of holding the vertical interval of the intermediate horizontal rope 23, a rope It is a rope net having a load transfer function between the net 24 and the intermediate lateral ropes 23 and a load transfer function between the intermediate lateral ropes 23 and the end lateral ropes 21, 22.
In this example, a rope net 24 intersects a plurality of ropes, and the form of a mesh net in which each intersection is fixed inslidably is described. However, the rope net 24 is a ring net in which a plurality of rope rings are chained. Good.
In this example, the rope net 24 is formed in span units in consideration of handleability and exchangeability, but the rope net 24 may be a net having a plurality of spans.

<3.4.1> Attaching Structure of Upper and Lower Sides of Rope Nets Referring to FIGS. 1 and 5, the upper and lower sides of each rope net 24 have respective end lateral ropes 21, via mooring members 26 such as shackles, 22 is supported for lateral sliding.
The upper and lower sides of the rope net 24 are connected to the end lateral ropes 21 and 22 in order to enable load transfer between the rope net 24 and the end lateral ropes 21 and 22, and the end lateral ropes This is to suppress the amount of deformation of the upper and lower sides of the protective net 20 after the impact by utilizing the elastic restoring forces of 21 and 22.
The upper and lower sides of the rope net 24 are moored so as to be slidable laterally with respect to the end lateral ropes 21 and 22 in order to avoid damage due to dragging of the rope net 24 at the time of impact.

<3.4.2> Attachment Structure of Left and Right Sides of Rope Nets Referring to FIGS. 1 and 3, the left and right sides of the rope net 24 are supported by the vertical ropes 13 bridged between the upper and lower sides of the respective columns 10. I am doing it.
The connection means on the left and right sides of each rope net 24 may be directly connected via a connection tool such as a shackle other than the illustrated embodiment using the vertical ropes 13.

<3.4.3> Attachment Structure of Rope Net and Intermediate Horizontal Rope The intersection of the intermediate horizontal rope 23 and the rope net 24 is non-slidably fixed by a fixing member 27 such as a wire clip.
The reason for fixing a plurality of places between each intermediate horizontal rope 23 and the rope net 24 is to keep the vertical interval of the intermediate horizontal rope 23 constant by the rope net 24 and the load between the intermediate horizontal rope 23 and the rope net 24 This is to enable transmission.

<3.5> Mesh material The mesh material 25 is a net material whose mesh size is smaller than that of the rope net 24 which covers the plurality of rope nets 24 and is connected to the end lateral ropes 21, 22 and the rope net 24 etc. It is attached by a coil etc.
The mesh material 25 is not an essential component and may be omitted.

<4> Load transfer structure of each constituent material of guard fence The load transfer structure between each constituent material in the guard fence described above is as follows.

<4.1> Between adjacent struts Loads can be transmitted in span units through the end lateral ropes 21 and 22 between adjacent struts 10.

<4.2> Between the support and the intermediate lateral rope The intermediate lateral rope 23 only intersects with the intermediate support 10a, and direct load transfer between the two materials 23, 10a is not performed, but the rope net 24 And the load transmission via the end side ropes 21, 22 is possible.
Load transmission over a plurality of spans is possible between the end post 10 and the end of the intermediate lateral rope 23.

Between the end lateral ropes 21 and 22 and the upper and lower sides of the rope net 24, load transfer in span units via the mooring tool 26 is possible.

<4.4> Between the end lateral ropes and the intermediate lateral ropes No direct load transfer takes place between the end lateral ropes 21, 22 and the intermediate lateral ropes 23. However, they were passed through the rope net 24. Load transfer in span units is possible.

<4.5> Between the mid-transverse rope and the rope net A span unit load transfer through the fixture 27 is possible between each mid-transverse rope 23 and the rope net 24.

<4.6> Between the intermediate lateral rope, the rope net and the end lateral rope The rope net 24 is not only for the plurality of intermediate lateral ropes 23 that undergo plastic deformation, but also for the end lateral ropes 21 and 22 that undergo elastic deformation. Even load transfer is possible.
That is, load transfer between the intermediate lateral ropes 23, the rope nets 24, and the end lateral ropes 21, 22 is possible.

<5> Interrelationship of each constituent material of the guard fence In the present invention, the load distribution of each constituent material constituting the guard fence is promoted to effectively function not only dynamic load but also static load. The relationship between the slip initiation force of the shock absorber 30 and the strength of each component material is set to satisfy the following relationship (1).

f ₁ <σ ₁ ≦ σ ₂ σσ ₃ <σ ₄ (1)

f ₁ : Slip initiation force σ ₁ of shock absorber 30: Tensile strength σ ₂ of rope net 24 ₂ : Tensile strength σ of intermediate lateral rope 23 ₃ : Tensile strength σ of end lateral ropes 21, 22 ₄ : Flexural strength of support 10

  In other words, at the time of receiving (when receiving pressure), before the rope net 24, the intermediate lateral ropes 23, and the end lateral ropes 21, 22 break, the intermediate lateral rope 23 starts to slip and acts on the blocking surface Can be transmitted to each support 10.

  Furthermore, in order to perform efficient energy absorption by deformation of the support 10 while suppressing brittle fracture (breaking of the rope material, etc.) of the protective net 20, the slip initiation force of the shock absorber 30 and the end lateral rope 21 , 22 and the bending strength of the support 10 are set to satisfy the following relational expression (2).

Σσ ₄ <((σ ₃ + f ₁ ) (2)

  In other words, at the time of receiving (when receiving pressure), breakage of the end lateral ropes 21, 22 can be avoided by deforming the support 10 in advance prior to breakage of the end lateral ropes 21, 22. ing.

[Function of guard fence]
The operation of the guard fence for each type of load will be described with reference to FIG.

<1> Dynamic Load A case where a dynamic load (falling stone, fallen soil, avalanche, etc.) collides with the central span of the protective net 20 shown in FIG. 6 will be described.
In addition, in FIG. 6, in order to make load transmission of the whole protection fence easy to understand, the rope net 24 is described only in the center span, and the description of the rope net 24 in the right and left both sides span is abbreviate | omitted.

<1.1> Transmission route (1)
The intermediate horizontal ropes 23 and the rope nets 24 constituting the protective net 20 plastically deform toward the valley side under dynamic load, and some of the energy is attenuated by the plastic deformation of these components 23 and 24.
When a specific rope net 24 located in the receiving span is plastically deformed toward the valley side, a load is transmitted to the plurality of other middle transverse ropes 23 through the rope net 24. The tension increases according to the amount of deformation of each of the intermediate horizontal ropes 23 and the rope net 24.

When the tension of each intermediate horizontal rope 23 exceeds the slip initiation force of the shock absorber 30, the end of the intermediate horizontal rope 23 slips and is attenuated, and the transfer load from the intermediate horizontal rope 23 to the end post 10b is reduced. .
Thus, the dynamic load applied to some of the intermediate lateral ropes 23 is distributed to the plurality of intermediate lateral ropes 23 and is damped by the shock absorber 30 provided near the end of each intermediate lateral rope 23, The load on the terminal support 10b is greatly reduced.

<1.2> Transmission route (2)
When the rope net 24 plastically deforms to the valley side following the plastic deformation of each intermediate lateral rope 23 located in the receiving span, the load is transmitted to the end lateral ropes 21a and 22a via the rope net 24 and the end The part horizontal ropes 21a and 22a are elastically deformed.
At this time, the load after being damped by the intermediate lateral ropes 23 and the shock absorber 30 is transmitted from the rope net 24 to the end lateral ropes 21a, 22a.

When the tension of the end lateral ropes 21a and 22a located in the receiving span increases, this tension is sequentially transmitted to the other adjacent end lateral ropes 21b and 22b and finally transmitted to the end post 10b.
In the process of sequentially transferring the load through the end lateral ropes 21a, 21b (22a, 22b) of the spans, the energy is attenuated by the strength of each of the columns 10.
Since the load transmitted to the intermediate lateral ropes 23 is the load after damping by the shock absorber 30, the load on the intermediate support 10a and the end support 10b is reduced.
Furthermore, when the bending force of each support 10 through the end portion lateral ropes 21a and 21b (22a and 22b) exceeds the strength of each support 10, the support 10 is deformed and energy is attenuated.

In the conventional protective fence in which the protective net is arranged in span units, the energy is attenuated by the strength of the two columns located in the receiving span.
On the other hand, in the present invention, not only the two intermediate columns 10a positioned in the receiving span through the respective end lateral ropes 21a and 21b (22a and 22b) but also the other columns 10a positioned outside the receiving span. , 10b can be sequentially transmitted, so that impact energy can be effectively attenuated.
Therefore, not only the load burden is reduced not only for the intermediate column 10a but also for the terminal column 10b, and it is not necessary to design the intermediate column 10a and the terminal column 10b to have higher strength than necessary.

<1.3> Influence range of shock absorbing action of shock absorber The influence range of shock absorbing action by the shock absorber 30 is not limited to the intermediate horizontal rope 23 alone.
The plurality of intermediate horizontal ropes 23 are configured to be able to transmit the load not only to the rope net 24 but also to the end horizontal ropes 21a and 21b (22a and 22b), so the impact of the buffer action of the shock absorber 30 is on the rope net 24 and end lateral ropes 21a, 21b (22a, 22b).
Therefore, by changing the slip start force of the shock absorber 30, it is possible to control the load (tension) acting on the intermediate lateral rope 23, the rope net 24, and the end lateral ropes 21a and 21b (22a and 22b). .

<1.4> Dynamic load damping performance As described above, the load transfer not only for the rope net 24 to the plurality of intermediate lateral ropes 23 but also for the end lateral ropes 21a and 21b (22a and 22b) The dynamic load acting on the central span of the protective net 20 can be efficiently damped through both of the transmission routes (1) and (2).
In particular, since the plurality of intermediate horizontal ropes 23 and the rope net 24 are plastically deformed at the time of impact, the damping energy can be increased as compared with the case of elastically deforming these components 23 and 24.

<1.5> About fence height of protection net If the shock absorbing device is temporarily inserted in each end lateral rope 21a, 21b (22a, 22b), the end lateral rope 21a, 21b (22a, 22b) is plastically deformed The reduction of the fence height at the time of the hit will become large.
On the other hand, in the present invention, since the shock absorbers are not interposed in the end lateral ropes 21a and 21b (22a and 22b), the end lateral ropes 21a and 22a are elastically deformed at the time of receiving and the elastic deformation occurs. The amount can be kept small.
Therefore, the protection fence of the present invention can suppress the reduction of the fence height to a small extent, and is effective against repeated dynamic loads.

<2> Static Load A case where a static load (snow load, deposited load such as deposited sediment and the like) acts on the protective net 20 shown in FIG. 6 will be described.

<2.1> Transmission route of static load When static load acts on the blocking surface of the protective net 20, static force is transmitted through the transmission routes (1) and (2) as in the case of the dynamic load. Dynamic load is dispersed.
The damping action of the load through the transmission routes (1) and (2) is the same as the dynamic load, so the description will be omitted.

<2.2> Regarding the Fuse Function of the Buffer Device The fuse function of the buffer device 30 will be described.
Static loads are distributed and transmitted to the rope net 24, the intermediate lateral ropes 23, the end lateral ropes 21a, 21 (22a, 22b), and the columns 10 through the transmission routes (1), (2).
In the protection fence of the present invention, the shock absorber 30 is taken before the tension acting on the rope net 24, the intermediate lateral ropes 23, and the end lateral ropes 21a, 21 (22a, 22b) reaches the breaking strength of these respective rope materials. Since the intermediate lateral ropes 23 are made to slip, breakage of the rope material constituting the protective net 20 can be prevented beforehand by the static load.
The striking device 30 exhibits a fuse function (a limiter function) for preventing breakage of the rope material constituting the protective net 20.
Therefore, even if static load more than expected is received, the function as guard net 20 can be held.

<3> Dual use of guard fences Conventional dual guard fences have a structure suitable for either dynamic load or static load, so the problem of large performance difference depending on load type is included. Was.
On the other hand, in the present invention, load transfer among all the constituent materials (rope net 24, middle horizontal rope 23, end horizontal ropes 21 and 22, middle column 10a, and terminal column 10b) constituting the protection fence. The load acting on a part of the protective net 20 can be dispersed widely and effectively damped.
Moreover, the guard fence of the present invention has the same load transfer route of the guard fence whether the load is a dynamic load or a static load, so it is possible to realize a combined guard fence having a small performance difference depending on the load type.

10 ... post 10a ... middle post 10b ... terminal post 11 ... support structure 12 ... hook 13 ... vertical rope 20 ... protection net 21 ...・ End side rope (upper)
22 ······ End horizontal rope (lower)
23 ··· Intermediate horizontal rope 24 ··· Rope net 25 ··· Mesh material 26 ··· Mooring 27 ··· Fixing 30 ··· Buffering device 31 ··· Buffering device Gripping means 32 of the support plate 33 of the shock absorber, connection bolt of the shock absorber

Claims (9)

A guard fence having a plurality of struts and a guard net extending between the struts,
A plurality of end lateral ropes spanned in span units between the upper part and the lower part of the adjacent struts;
Multiple intermediate lateral ropes straddled in multiple stages between multiple columns,
A buffer device interposed between the end of each intermediate lateral rope and the end post to hold the intermediate lateral rope in a slippable manner;
It consists of a rope net arranged to cover multiple middle horizontal ropes,
The plurality of intermediate lateral ropes and the rope net are fixed so that load transfer between the intermediate lateral rope, the rope net and the end lateral rope is possible, and the upper and lower sides of the rope net are end Characterized by being connected to a side rope,
Guard fence.   The guard fence according to claim 1, characterized in that the slip initiation force of the shock absorber is smaller than the tensile strength of the rope net, the intermediate lateral rope, and the end lateral rope. The slip initiation force of the shock absorber, the tensile strength of the rope net, the tensile strength of the intermediate lateral rope, the tensile strength of the end lateral rope, and the flexural strength of the support are set to satisfy the following relationship (1) The guard fence according to claim 1 or 2, characterized in that.
f ₁ <σ ₁ ≦ σ ₂ σσ ₃ <σ ₄ (1)
f _1: the slip start force shock absorber sigma _1: Tensile strength of the rope net sigma _2: Tensile strength of the intermediate horizontal rope sigma _3: end transverse tensile strength of the rope sigma _4: flexural strength of the post The slip initiation force of the shock absorber, the tensile strength of the end lateral rope, and the bending strength of the support are set so as to satisfy the following relational expression (2): Guard fence described in Section.
Σσ ₄ <((σ ₃ + f ₁ ) (2)
f ₁ : Slip initiation force of shock absorber σ ₃ : Tensile strength of end lateral rope σ ₄ : Bending strength of strut   The guard fence according to any one of claims 1 to 3, wherein the rope nets are independent in span units of a support.   The guard fence according to any one of claims 1 to 3, wherein the upper and lower sides of the rope net are anchored so as to be able to slide laterally relative to the end lateral rope.   The rope net according to any one of claims 1 to 3, which is a mesh net crossing a plurality of ropes and in which each crossing portion is non-slidably fixed. Guard fence.   The guard fence according to any one of claims 1 to 3, 5 and 6, wherein the rope net is a ring net in which a plurality of rope rings are linked.   The guard fence according to claim 1, wherein a mesh material is disposed on the surface of the rope net by polymerization.

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