JP6742619B2 - Method of repairing guard fence - Google Patents

Description

The present invention relates to a protective fence that captures fallen materials such as falling rocks, and more particularly to a method for repairing a protective fence that can reduce the burden of impact load on a terminal support and improve the protective function.

Many protective fences for small-scale rockfalls of about 50 kJ are installed near roads and railways.
Explaining with reference to FIG. 6, a conventional protective fence 10B has a multi-stage structure in which H steel columns (terminal column 20, intermediate column 21) standing upright at predetermined intervals and these columns 20, 21 are provided. It comprises a plurality of horizontal ropes 22 that are horizontally extended, and a wire net 23 that is attached across the plurality of horizontal ropes 22.
Each horizontal rope 22 is laid across a plurality of intermediate columns 21, and the ends thereof are connected to the terminal columns 21 via cable end fittings 30.

FIG. 7 shows a mounting structure of the horizontal rope 22 using the rope end fittings 30.
The rope end fitting 30 has a tubular terminal socket 31 fixed to the end of the horizontal rope 22 via a wedge body, and a terminal bolt 32 that can be locked to the terminal socket 31.
The right end of the terminal bolt 32 made of both screw bolts is locked to the terminal socket 31 by screwing a locking nut 33 into a threaded portion that penetrates the left end of the terminal socket 31.
The left end of the terminal bolt 32 is connected to the terminal strut 20 by screwing a fixing nut 34 to a threaded portion that penetrates the web 20b of the H steel terminal strut 20, and the horizontal rope 22 is stretched by tightening the fixing nut 34. It is set up.

In designing the protective fence 10B, strength design has been performed for each material such as the intermediate support column 21 and the horizontal rope 22 based on the design guideline of "Handbook of Rock Fall Countermeasures (Japan Road Association)". With the revision of the "Handbook for Countermeasures against Falling Rocks" in December, the terminal support column 20 has been newly added to the inspection target.
When the existing protective fence was verified, it was found that there are not a few protective fences 10B having terminal columns 20 that do not meet the new standard.
With respect to the protective fence 10B including the terminal support column 20, which is feared to have insufficient strength, countermeasure work has become an urgent issue.

JP-A-7-197423

There are several possible countermeasures for the existing protective fence 10B, but these countermeasures have the following problems to be solved.
<1> As one of the countermeasure works, a method of replacing the terminal support column 20 with an upsized one is considered.
In order to carry out this countermeasure work, after removing the end portions of all the horizontal ropes 22 from the terminal support columns 20, the old terminal support columns 20 are removed and replaced with new size of the terminal support columns, so that all the horizontal ropes 22 It is necessary to perform a series of operations such as reconnecting the end of the to the new terminal support.
In particular, in the type in which the terminal column 20 is embedded in the concrete foundation 11, it is very difficult to chip the rooting portion of the terminal column 20.
Therefore, it takes a lot of time and labor to replace the terminal column 20, and the replacement cost becomes very high.
<2> As a method of reinforcing the terminal support column 20, there is a method of installing an additional diagonal member 25 in addition to the existing steel diagonal member 24 provided between the terminal column 20 and the concrete foundation 11.
In order to implement this reinforcing measure, new bolt holes must be opened on site in the flange 20b of the terminal column 20, and the lower portion of the additional diagonal member 25 must be embedded in the concrete foundation 11.
When a bolt hole is formed in the terminal column 20, not only a corrosion problem occurs, but also in order to bury the lower portion of the additional diagonal member 25 in the concrete foundation 11, it is necessary to perform a chiseling work that requires a lot of working time and labor.

The present invention has been made in view of the above points, and an object thereof is to provide at least one of the following methods for repairing a protective fence.
<1> To be able to comply with the new standard by reducing the load of impact load in the short axis direction of the terminal support without replacing the terminal support.
<2> To effectively utilize the existing cable end fittings and take measures for the terminal support in a short time with little labor and low cost.

INDUSTRIAL APPLICABILITY The present invention provides a plurality of horizontal ropes that are vertically erected at a predetermined interval and that include an H-shaped steel intermediate support column and a terminal support column, a plurality of horizontal ropes horizontally extended between these support columns, and a plurality of horizontal ropes. A method of repairing a protective fence, comprising: a wire mesh installed across the terminal, and a rope end fitting provided with a terminal socket and a terminal bolt between the terminal of each of the horizontal ropes and the terminal support, the terminal comprising: were excised terminal portion of the plurality of horizontal ropes are connected to the insufficient strength range excluding the healthy range of the column at a predetermined length, the terminal socket attached to the cut end of the horizontal rope shortened by cutting, resection It said terminal socket attached to the cut end of the horizontal rope shortened and, interposed joint unit having a buffering function between the terminal bolt engaged with the terminal posts, the weak axis of the terminal post at受撃as can suppress deformation toward the direction, the tension of more constant the horizontal rope acts, characterized in that the joint unit attenuates the tension transmitted to the insufficient strength range of the terminal posts.
In another form of the present invention, the friction sliding the joint unit, and possible jaw fittings connected to the terminal socket, and the slip rope connected at one end to the jaw fittings, which slidably grips the rope portion of the slip rope has a formula of the buffer device, and eye nut coupled at one end to the dampener, the jaw bracket connected to the terminal socket which is attached to the cut end of the horizontal rope shortened by cutting off, locking the terminal posts joint unit screwed to the eye nut to the terminal bolt that is are interposed.
In another aspect of the present invention, the friction-sliding type shock absorber includes a wedge body that can be held on an outer peripheral surface of a slip rope, a sleeve having a tapered hole that can accommodate the wedge body, and a coupling that can accommodate the sleeve. And a shock absorber is connected to the eye nut through the connection cover.

The present invention has at least one of the following effects.
<1> By incorporating a joint unit having a cushioning function in the end portion of the horizontal rope connected to the insufficient strength range of the terminal support, the impact load of the terminal support is reduced and the short axis of the terminal support in the insufficient strength range. The deformation toward the direction can be suppressed.
Therefore, it is necessary to comply with the new standards revised in the "Occupational Handbook for Rocks" without changing the size of the terminal supports or arranging additional diagonal members and leaving the existing terminal supports. You can
<2> Since the joint unit can be assembled by effectively utilizing the rope end fittings, the joint unit can be assembled at low cost in a short time.
<3> By incorporating the joint unit in the range where the strength of the terminal support is insufficient, it is possible to suppress the deformation of the terminal support in the weak axis direction at the time of receiving an impact, so that the original strength of the terminal support can be exhibited.

Front view of the terminal part of the protective fence that incorporates the joint unit Perspective view of joint unit Exploded view of joint unit Explanatory drawing of shock absorber with a part broken Explanatory drawing of the process of cutting off the end part of the horizontal rope Front view of a protective fence on which the present invention is based Illustration of horizontal rope mounting structure using rope end fittings

The present invention will be described in detail with reference to the drawings.

<1> Prerequisite protective fence FIG. 6 shows an existing protective fence 10B on which the present invention is premised.
This protective fence 10B is provided with H-shaped steel columns (terminal columns 20, intermediate columns 21) standing upright at a predetermined interval, a plurality of horizontal ropes 22, and a wire net 23.
The horizontal ropes 22 are arranged on the slope mountain side, the slope valley side, or the center of each intermediate column 21, and the ends of all the horizontal ropes 22 are connected to the terminal column 20 via rope end fittings 30.
The connection structure between the end of the horizontal rope 22 and the terminal support column 20 using the rope end fitting 30 is as described above (see FIG. 7).
The protective fence 10B may be of a type that does not include the existing diagonal members 24, or may be of a type in which a spacing member is provided in the vertical direction so as to intersect the plurality of horizontal ropes 22.

<2> Insufficient Strength Range of Terminal Strut In the protective fence 10B shown in FIG. 6, the upper half of the terminal strut 20 is the insufficient strength range L _{1 and} the lower half of the terminal strut 20 has the sound range L _2. Shows the morphology.
The insufficient strength range L ₁ of the terminal support column 20 may not satisfy the new standard of “Handbook of Rock Fall Countermeasures”.
The insufficient strength range L ₁ means a range in which the strength in the weak axis direction is insufficient when an impact load in the weak axis direction (the direction in which the horizontal rope 22 is stretched) is applied as a bending force to the terminal support columns 20.

According to the present invention, the terminal portion of the horizontal rope 22 connected to the insufficient strength range L ₁ of the terminal support column 20 is cut off by a predetermined length, and a joint unit 40 having a cushioning function, which will be described later, is incorporated in this cutting range. The load of the impact load on the column 20 is reduced to suppress the deformation of the terminal column 20 in the short-axis direction in the insufficient strength range L ₁ .

<3> Joint Unit The joint unit 40 is a substitute material for the horizontal rope 22 having a cushioning function, which is interposed between the terminal column 20 and the horizontal rope 22 left after cutting, and both ends of the joint unit 40 are cable ends. The structure is such that it can be connected to a terminal socket 31 and a terminal bolt 32, which are components of the metal fitting 30, respectively.

Explaining the joint unit 40 illustrated in FIGS. 2 to 3, the joint unit 40 includes a jaw metal fitting 50 that can be locked to the terminal socket 31, and a locking bolt 52 on a bifurcated jaw portion 51 at one end of the jaw metal fitting 50. Slip rope 60 that connects the jaw metal fitting 50 and the shock absorber 70, a friction slide type shock absorber 70 that holds the slip rope 60, and an eye nut 80 that connects the shock absorber 70 and the locking bolt 71. Have and.

<3.1> Jaw Metal Fitting Referring to FIGS. 2 and 3, the jaw metal fitting 50 is a member that connects the terminal socket 31 and the slip rope 60, and includes a shaft portion 52 formed with a male screw and a shaft portion 52. It has a bifurcated jaw portion 51 at one end and a bolt-shaped or pin-shaped locking body 54 that can be inserted into a pin hole 53 formed in the bifurcated jaw portion 51.
The shaft portion 52 can be connected to the terminal socket 31 by inserting it into the terminal socket 31 and screwing the locking nut 33.

<3.2> Slip Rope Referring to FIGS. 2 and 3, the slip rope 60 is a steel rope that connects the jaw fitting 50 and the shock absorber 70, and a ring portion 61 is formed at one end of the rope portion 62. ing.
The ring portion 61 of the slip rope 60 is locked to the locking body 54 and can be connected to the jaw fitting 50, and the rope portion 62 of the slip rope 60 is slidably held by the shock absorber 70. The total length of the slip rope 60 is appropriately selected in consideration of the sliding distance.

<3.3> Shock Absorber The shock absorber 70 accommodates the wedge body 71 that can be held on the outer peripheral surface of the slip rope 60, the sleeve 74 with the flange 73 having the tapered hole 72 that can accommodate the wedge body 71, and the sleeve 74. Possible connection cover 76.
A wedge body 71 that inserts and grips the slip rope 60 and a sleeve 74 that accommodates the wedge body 71 constitute a friction-sliding type shock absorber.

The wedge body 71 can hold the rope portion 62 of the slip rope 60, and its outer peripheral surface is formed in a tapered shape.
The tapered hole 72 of the sleeve 74 has a stopper 72a in its small-diameter opening, and when the small-diameter tip portion of the wedge body 71 abuts against the stopper 72a, the amount of sliding of the wedge body 71 to the right is set to a fixed position. It can be regulated.

The cushioning tool is not limited to the form illustrated in this example, and the wedge body 71 is displaced toward the smaller diameter side of the sleeve 74 to gradually increase the frictional resistance between the slip rope 60 and the wedge body 71. If the tension exceeds the peripheral frictional resistance, the slip rope 60 can slide to attenuate the tension, and a known friction sliding type shock absorber can be applied.

The connection cover 76 is formed by dividing a tubular body having a different diameter into two, and is capable of locking the sleeve 74 housed in the tubular portion 77 on the right side thereof.
A pull-out window 78 for pulling out the slip rope 60 to the outside of the connecting cover 76 is formed at the center of the connecting cover 76.
A bolt hole is formed on the left side of the connecting cover 76, and a nut 79 screwed into a locking bolt 75 inserted into the bolt hole is tightened to unify the two-divided cover 76 into an inseparable unit. be able to.

<3.4> Eye Nut The eye nut 80 is a member for connecting the terminal bolt 32 and the shock absorber 70, and the nut portion 81 that can be screwed to the terminal bolt 32 and the locking bolt 75 can be locked. It has a ring portion 82.

[How to repair the fence]
Next, the method of repairing the protective fence will be explained.

<1> Excision of Terminal Portion of Horizontal Rope Explaining with reference to FIG. 5, of the plurality of horizontal ropes 22 connected to the terminal support column 20 via the cable end fittings 30, the insufficient strength range L ₁ of the terminal support column 20. The end portion of only the horizontal rope 22 located at is cut off over a certain range, and the horizontal rope 22 connected to the healthy range L ₂ of the terminal support column 20 excluding the insufficient strength range L ₁ is not cut and left as it is. deep.
When the horizontal rope 22 is separated from the terminal column 20, the cable end fitting 30 is loosened to separate the terminal socket 31 and the terminal bolt 32.

<2> Replacement of Terminal Socket The terminal socket 31 remains at the end of the cut horizontal rope 22.
Therefore, the wedge-fixed terminal socket 31 and the horizontal rope 22 are separated, and the recovered terminal socket 31 is cut and replaced with a cut end of each horizontal rope 22 that is shortened.

<3> Assembly of Joint Unit Next, the joint unit 40 shown in FIGS. 2 and 3 is prepared, and the joint unit 40 is assembled in the region between the cut end of the horizontal rope 22 left after cutting and the terminal support 20. ..
As the joint unit 40, one that has been unitized in advance as shown in FIG. 3 may be used, or it may be unitized while assembling on site.
In any of the forms, after inserting the shaft portion 52 of the jaw metal fitting 50 on the right side of the joint unit 40 into the terminal socket 31, the locking nut 33 is screwed to the shaft portion 52 of the jaw metal fitting 50 for connection. At the same time, the left eye nut 80 of the joint unit 40 is screwed onto the terminal bolt 32 for connection.

When inserting the joint unit 40, the joint unit 40 can be assembled by utilizing the terminal socket 31 and the terminal bolt 32 that have been separated and collected, so that special jigs and equipment can be used or special connection work can be performed on site. Not only does this not have to be done, but the work of assembling the joint unit 40 can be performed easily in a short time.

<4> Tension of Horizontal Rope Just by inserting the joint unit 40 between them, the slack remains on the horizontal rope 22.
Therefore, the slip rope 60 is pulled by hand toward the terminal column 20 to shorten the rope length between the jaw fitting 50 and the shock absorber 70, and the fixing nut 34 of the terminal bolt 32 penetrating the web 20b of the terminal column 20 is fixed. To tighten the horizontal rope 22 without slack.

The cutting operation of the horizontal rope 22 and the assembling operation of the joint unit 40 are performed to obtain the protective fence 10A as shown in FIG.
In the protection fence 10A, the terminals of the horizontal ropes 22 are connected via the joint unit 40 in the insufficient strength range L ₁ in the upper half of the terminal columns 20, and the horizontal ropes are connected in the healthy range L ₂ in the lower half of the terminal columns 20. Twenty-two terminals are connected via a cable end fitting 30.

[Protective performance of protective fence]
Next, referring to FIG. 1, the receiving performance of the protective fence 10A will be described. Particularly, the load burden in the insufficient strength range L ₁ of the terminal support column 20 will be described.

<1> When Impact Load is Small When the tension (impact load) acting on the horizontal rope 22 is smaller than the sliding resistance between the shock absorber 70 incorporated in the joint unit 40 and the slip rope 60, the slip rope 60 Does not slide.
Therefore, when the tension acting on the horizontal rope 22 is small, the tension of the horizontal rope 22 is directly transmitted to the terminal column 20, and is supported by the rigidity of the terminal column 20.

<2> When Impact Load is Large When the tension acting on the horizontal rope 22 exceeds the frictional resistance of the shock absorber 70 incorporated in the joint unit 40, sliding occurs between the shock absorber 70 and the slip rope 60 to cause tension. Is attenuated.
Therefore, even if a large tension is applied to the horizontal rope 22, the tension transmitted to the insufficient strength range L ₁ of the terminal support column 20 is reduced and the load burden is reduced, so that the terminal support column 20 is bent and deformed in the weak axis direction. Can be effectively suppressed.

In particular, in the protective fence 10B of FIG. 6 in which the joint unit 40 is not incorporated, the terminal support column 20 is deformed in the weak axis direction of the terminal support column 20 before exerting the rigidity of the strong axis (slope valley side) when receiving. Therefore, there is a risk that the original strength of the terminal support column 20 cannot be exhibited.
On the other hand, in the protective fence 10A of FIG. _{1 in} which the joint unit 40 is incorporated in the insufficient strength range L ₁ of the terminal support column 20, the deformation of the terminal support column 20 in the weak axis direction can be suppressed at the time of a strike. It is possible to exhibit the original strength of 20.

As described above, by simply interposing the joint unit 40 between the terminal support column 20 and the horizontal rope 22 located in the insufficient strength range L ₁ of the terminal support column 20, the terminal support column 20 can be replaced with the increased size of the terminal support column 20 or added. It is possible to comply with the new standard revised in the “Falling Stone Countermeasures Manual” in a state where the existing terminal support columns 20 remain without additionally disposing the diagonal members 25.

10A... Guard fence 10B... Guard fence 11... Concrete foundation 20... Terminal strut 20a... Strut web 20b... Strut flange 21... Intermediate strut 22...・・Horizontal rope 23 ・・・・ Wire mesh 24 ・・・・ Existing diagonal members 25 ・・ Additional diagonal members 30 ・・ Cable end fittings 31 ・・・・ Terminal sockets 32 for cable end fittings ・・・・Terminal bolt 33 of rope end fitting... Locking nut 34... Fixing nut 40... Joint unit 50... Jaw fitting 51... Shaft 52 of jaw fitting... Jaws 54 of jaw metal fittings... Locking body 60... Slip rope 61... Slip rope ring 62... Slip rope rope 70... Shock absorber 71... ··· Wedge body 72 ··· Tapered hole 73 in sleeve ··· Flange 74 · · · Sleeve 75 · · · Locking bolt 76 · · · Connection cover 77 · · · · Cylindrical portion 78 ...・Drawing window 80 of the connecting cover ・・・・Eye nut 81・・・ ・Eye nut nut portion 82 ・・Eye nut ring portion L ₁・・・Less strength range of terminal support ₂ ... Healthy range of terminal support

Claims (3)

A pillar including an H-shaped steel intermediate pillar and a terminal pillar, which are erected at a predetermined interval, a plurality of horizontal ropes horizontally laid between these pillars, and mounted across the plurality of horizontal ropes. An existing protective fence comprising a wire net, and a cable end fitting having a terminal socket and a terminal bolt provided between the end of each horizontal rope and the terminal support,
Cut off the terminal portion of a plurality of horizontal ropes that are connected to the insufficient strength range excluding the sound range of the terminal column at a predetermined length,
The terminal socket attached to the cut end of the cut to the horizontal rope shortened,
It said terminal socket attached to the cut end of the cut to the horizontal rope shortened, a joint unit having a buffering function between the terminal bolt engaged with the terminal posts interposed,
As can suppress deformation toward the weak axis direction of the terminal posts during受撃, the tension of more constant the horizontal rope acts, characterized in that the joint unit attenuates the tension transmitted to the insufficient strength range of the terminal posts And
How to repair the protective fence. The joint unit, and possible jaw fittings connected to the terminal socket, and the slip rope connected at one end to the jaw fittings, and a buffer device of the friction sliding of the slidably gripping the rope portion of the slip rope, one end and a eye nut coupled to the buffer device, the said terminal socket attached to the cut end of the horizontal rope shortened by cutting connecting the jaw fittings, the eye nut to the terminal bolt engaged with the terminal posts The method for repairing a protective fence in a protective fence according to claim 1, characterized in that the joint unit is interposed by screwing. The friction-sliding type shock absorber includes a wedge body that can be held on the outer peripheral surface of the slip rope, a sleeve having a tapered hole that can accommodate the wedge body, and a connection cover that can accommodate the sleeve. The method for repairing a protective fence according to claim 2, wherein the shock absorber is connected to the eye nut through the cover.

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