JP2023158754A - Protective fence, buffer device, and method for manufacturing the same - Google Patents

Abstract

To provide a protective fence provided with a buffer device capable of relatively easily changing the buffer performance in the buffer device used for the protective fence or the like, and to provide the buffer device and its manufacturing method.SOLUTION: A protective fence is provided with a plurality of upright posts 11, a rope body 13 stretched between the posts 11, and a buffer device 15 provided at a connection point between the posts 11 and the cord body 13 and having one or a plurality of tubular members 151, wherein the buffer device 15 is configured so that a tension applied to the cord body 13 is applied to the tubular member 151 in its axial direction, and is provided with a load conversion part which applies at least a part of a compressive load or a tensile load applied to the tubular member 151 in its axial direction as a bending load.SELECTED DRAWING: Figure 2

Description

The present invention relates to a protective fence equipped with a shock absorber, a shock absorber, and a manufacturing method thereof.

In order to protect roads, houses, etc. from falling rocks on sloped areas, etc., protective fences (rockfall protection fences, avalanche prevention fences, etc.) are used that are installed on the slope side of the roads, houses, etc. to be protected. A typical protective fence has a structure in which an upper member consisting of posts, wire ropes, and wire mesh is supported by a concrete foundation, etc., and this prevents disasters by catching falling rocks from above the slope. be.
Some of these protective fences are equipped with a shock absorbing device for absorbing the shock caused by falling rocks, and Patent Documents 1 and 2 describe protective fences having such a shock absorbing device. .

JP 2019-027077 Publication Japanese Patent Application Publication No. 2020-117930

Conventional shock absorbers that are often used include a method in which a wire rope is sandwiched between steel plates or clips to reduce the impact force by the effect of dynamic friction, and a method that reduces the impact force by reducing the size of a 50 cm steel ring to 20 cm. There is a method of reducing impact force by deforming a member such as a plate-shaped member and using the resistance force generated during the deformation.
When changing the specifications (buffer performance) of conventional shock absorbers, it is often necessary to review the overall structure or change the components (materials). It wasn't.

In view of the above-mentioned points, the present invention provides a protective fence equipped with a buffer device, a buffer device, and a method for manufacturing the same, in which the buffering performance can be relatively easily changed in a buffer device used for a protective fence, etc. The purpose is to

(Configuration 1)
A plurality of erected struts, a cable stretched between the struts, and a buffer device provided at a connection point between the strut and the cable or in the middle of the cable, the buffer comprising one or more a shock absorber having a tubular member, the shock absorber being configured such that the tension acting on the cord is applied to the tubular member in the axial direction thereof, thereby causing tension in the axial direction of the tubular member. A protective fence comprising a load converter that applies at least a part of an applied compressive load or tensile load as a bending load.

(Configuration 2)
The protective fence according to configuration 1, wherein the load conversion section is configured by an enlarged diameter section or a reduced diameter section provided in the tubular member.

(Configuration 3)
The protective fence according to configuration 2, wherein a plurality of the enlarged diameter portions, the plurality of diameter reduced portions, or both of these are formed in the tubular member.

(Configuration 4)
4. The protective fence according to any one of configurations 1 to 3, wherein the plurality of tubular members are arranged in series.

(Configuration 5)
5. The protective fence according to any one of configurations 1 to 4, wherein, in the tubular member, a yield point against a bending load at the load converting portion is lower than a yield point against a compressive load or a tensile load at other locations.

(Configuration 6)
A connection member that connects the strut and the cable body via the shock absorbing device, the strut attachment member being attached to the strut, and the cable body or the cable body being inserted through the inside of the one or more tubular members. a first locking member that fastens the cable end fitting attached to the cable body on one side of the one or more tubular members; The protection according to any one of configurations 1 to 5, comprising a connecting member that abuts the tubular member directly or through another member, and has a second locking member that is connected to the column attachment member. fence.

(Configuration 7)
The strut attachment member is a wire rope whose end is machined with a stopper, and the second locking member is a long hole into which the wire rope can be inserted, and the stopper is an elongated hole through which the stopper cannot be inserted. The protective fence according to configuration 6, further comprising an elongated hole in which an enlarged diameter hole portion through which the retaining metal fitting can be inserted is formed.

(Configuration 8)
The ends of the retaining fittings are machined at both ends of the wire rope, and the enlarged diameter hole is formed in the center of the elongated hole, so that the A portion through which the retaining metal fitting cannot be inserted is formed in the elongated hole, and the enlarged diameter hole portion also functions as an insertion hole through which the cable body or the cable end fitting attached to the cable body is inserted. The protective fence described in 7.

(Configuration 9)
The method for assembling the connecting member in the protective fence according to configuration 8, wherein the wire rope is wound around the support, and the retaining metal fittings at both ends are inserted into the enlarged diameter hole, and then the expanded diameter hole is inserted. a step of moving the retaining metal fittings to the portions on both sides of the diameter hole portion into which insertion is not possible, and inserting the cable body or the cable end metal fittings attached to the rope body into the enlarged diameter hole portion; An assembling method comprising the step of passing through one or more tubular members and fastening with the first locking member.

(Configuration 10)
A buffer device for buffering tension acting on a cable body, comprising one or more tubular members to which the tension force acting on the cable body is applied in the axial direction, and at least a compressive load or a tensile load applied in the axial direction of the tubular member. A shock absorber equipped with a load converter that applies a portion of the load as a bending load.

(Configuration 11)
The shock absorber according to configuration 10, wherein the load conversion section is configured by an enlarged diameter section or a reduced diameter section provided in the tubular member.

(Configuration 12)
The shock absorber according to configuration 11, wherein the tubular member has a plurality of the enlarged diameter portions, the plurality of diameter reduced portions, or both thereof.

(Configuration 13)
13. The shock absorber according to any one of configurations 10 to 12, wherein a plurality of the tubular members are arranged in series.

(Configuration 14)
14. The shock absorber according to any one of configurations 10 to 13, wherein, in the tubular member, a yield point against a bending load at the load converting portion is lower than a yield point against a compressive load or a tensile load at other locations.

(Configuration 15)
The method for manufacturing a protective fence according to configuration 3, wherein the buffering performance of the shock absorber is changed by changing the number of the enlarged diameter portions or the reduced diameter portions.

(Configuration 16)
The method for manufacturing a protective fence according to configuration 4, wherein the buffering performance of the shock absorber is changed by changing the number of the tubular members.

(Configuration 17)
The method for manufacturing a protective fence according to configuration 2 or 3, wherein the buffering performance of the shock absorbing device is changed by changing the width or height of the enlarged diameter portion or the reduced diameter portion.

(Configuration 18)
The method for manufacturing a shock absorber according to Configuration 12, wherein the shock absorbing performance is changed by changing the number of the enlarged diameter portions or the reduced diameter portions.

(Configuration 19)
The method for manufacturing a shock absorber according to Configuration 13, wherein the shock absorbing performance is changed by changing the number of the tubular members.

(Configuration 20)
The method for manufacturing a shock absorber according to Structure 11 or 12, wherein the shock absorbing performance is changed by changing the width or height of the enlarged diameter portion or the reduced diameter portion.

According to the protective fence equipped with a shock absorbing device, the shock absorbing device, and the manufacturing method thereof of the present invention, it is possible to relatively easily change the shock absorbing performance of a shock absorbing device used for a protective fence or the like.

A diagram showing a protective fence (rockfall protection and avalanche prevention common fence) according to an embodiment of the present invention A diagram showing a connection part of a buffer device of a protective fence according to an embodiment. Diagram showing the tubular member of the shock absorber A perspective view showing the second locking member (bracket material) of the connecting member Diagram showing the specifications of the tubular member used for the impact test (and static load test) of the shock absorber Diagram showing test equipment for impact testing of shock absorbers Diagram showing test results of impact test of shock absorber Diagram showing test results of impact test of shock absorber Diagram showing test results of impact test of shock absorber Diagram showing the specifications of the tubular member used in the static load test of the tubular member Diagram showing test equipment for static load testing of tubular members Diagram showing the test results of a static load test on tubular members Diagram showing the test results of a static load test on tubular members Diagram showing the test results of a static load test on tubular members Diagram showing the test results of a static load test on tubular members Diagram showing the specifications of the guard fence used in the guard fence impact test Diagram showing test equipment for impact testing as a protective fence Diagram showing the test results of the impact test as a protective fence Diagram showing the test results of the impact test as a protective fence Diagram showing the test results of the impact test as a protective fence Diagram showing the test results of the impact test as a protective fence A diagram showing another example of a connecting member Diagram showing an example of using a shock absorber to connect intermediate struts and cables A diagram showing another example of a tubular member

Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the following embodiment is one form of embodying the present invention, and does not limit the present invention within its scope.

FIG. 1 shows a protective fence according to an embodiment of the present invention. FIG. 1(a): Front view (view from above the slope), FIG. 1(b): Side view, FIG. 1(c): Top view, FIG. 1(d): A top view showing the attachment structure for one cable 13.
The protective fence 1 of this embodiment is used as a rockfall protection fence that is installed on the slope side of the road, house, etc. to be protected in order to protect roads, houses, etc. from falling rocks, etc. on a slope (at or near the slope). This is a common fence for rock fall protection and avalanche prevention that also functions as an avalanche prevention fence that prevents avalanches from occurring.
The protective fence 1 of this embodiment is
A terminal support 11 erected at both ends;
an intermediate strut 12 disposed between the terminal struts 11;
A rope body 13 made of a wire rope or the like stretched between the terminal supports 11;
A mesh body 14 made of a wire mesh or the like is provided between the respective supports (between the terminal supports 11, between the terminal supports 11 and the intermediate supports 12, or between the intermediate supports 12). From the viewpoint of visibility, only a part of the net body 14 is displayed),
A buffer device 15 provided at the connection point between the terminal strut 11 and the cable body 13;
A support member 17 provided at the upper part between each column and maintaining the spacing between each column;
a spacing member 18 for maintaining the spacing between each cable body 13;
It is equipped with

Both the terminal support 11 and the intermediate support 12 are formed of steel pipes, and are filled with filler (mortar) during construction. Note that the terminal columns and intermediate columns themselves can be of any type with the necessary strength, and the structure (foundation) that supports them can also be of any type that generates the necessary supporting force (for example, concrete foundations, ground It is possible to use a sheath pipe method in which a support is built into a steel pipe buried inside as a sheath (this is adopted in this embodiment), a method in which the support is supported with piles or anchor bolts, etc.
The support member 17 that maintains the spacing between the pillars is a support member that resists the force acting on the pillars to cause them to fall inward when the impact from receiving a falling rock is transmitted to the pillars. If the strength provided by the pillar itself (and the foundation) is sufficient, the support material 17 is not necessarily necessary.
The terminal struts 11, the intermediate struts 12, the mesh body 14 made of wire mesh, etc., the spacing members 18, the support materials 17, and their attachment structure are not directly related to the present invention, and are not disclosed in, for example, patents. Since any one, such as the one disclosed in Publication No. 6991697, can be adopted, further explanation will be omitted here.

2 is a diagram showing the state in which the shock absorber 15 is connected, FIG. 2 (a) is a top view, FIG. 2 (b) is a front view, and FIG. It is a figure which shows the U-shaped hook 111 part.
The buffer device 15 buffers the tension acting on the cable 13, and includes a plurality of tubular members 151 arranged in series so that the tension acting on the cable 13 is applied in the axial direction, and a plurality of tubular members 151. It is composed of a plurality of washers 152 arranged between and at the ends.
Note that the washer 152 allows the tubular members 151 to be slightly misaligned (even if the axes of the tubular members 151 are slightly misaligned, the load is appropriately transmitted to each member). It is a member of For example, if the axis of the tubular member 151 is prevented by a cable end fitting 162 inserted into the inside of the tubular member 151, which will be described later, and there is no problem in transmitting the load to each member, the washer 152 is not necessarily necessary.

FIG. 3 is a diagram showing the tubular member 151, with FIG. 3(a) being a perspective view and FIG. 3(b) being a conceptual diagram for explaining the function of the load conversion section 1511.
In this embodiment, the tubular member 151 is formed based on a steel pipe, and performs load conversion to apply at least part of the compressive load or tensile load applied in the axial direction as a bending load (converts the compressive or tensile load to a bending load). 1511.
The load conversion section 1511 is constituted by an enlarged diameter section obtained by enlarging a part of a steel pipe. The enlarged diameter portion of the steel pipe can be formed by bulge forming or the like. Although the enlarged diameter portion can be formed using a method other than bulge forming, bulge forming is preferable because it allows the enlarged diameter portion to be formed while keeping the wall thickness uniform.
Due to the formation of the enlarged diameter portion which is the load conversion portion 1511, when a compressive load or a tensile load is applied in the axial direction (vertical direction in FIG. 3) of the tubular member 151, a moment is generated in the enlarged diameter portion. At the section, compressive or tensile loads will be converted into bending loads.
FIG. 3(b) shows a conceptual diagram for explaining the function of the load converter 1511. As shown in the figure, for example, when a compressive load is applied in the axial direction of the tubular member 151, a bending moment acts on the load converter 1511, causing the load converter 1511 to bend. The bending deformation in the load converter 1511 is an elastic deformation up to a predetermined load, and returns to the original shape when the load is removed. On the other hand, if the load exceeds a predetermined value, plastic deformation occurs.
The load capacity of the elastic region and the energy consumed by plastic deformation (ie, cushioning performance) can be controlled by changing the width W or height H of the enlarged diameter portion (or reduced diameter portion). In addition, the cushioning performance can be changed by selecting the material forming the tubular member, the diameter and thickness of the tubular member, etc. The buffering performance can also be changed by increasing or decreasing the number of enlarged diameter portions (or reduced diameter portions) formed.

As shown in FIG. 1, a cable body 13 made of a wire rope or the like is connected to a terminal support 11 via a shock absorber 15 at both ends thereof. Note that the cable body 13 is attached to the intermediate support 12 so as to be slidable in the width direction (horizontal direction in FIG. 1) using a U-shaped hook or the like. Moreover, each cable body 13 is fixed to the spacing member 18 by a wire grip.
With these configurations, when an impact such as a falling rock is applied, the resulting load is transmitted through each rope body 13 and transmitted to the terminal support 11 via the shock absorber 15 (buffered).

As shown in FIG. 2, the terminal support 11 and the cable body 13 are connected by a connecting member 16 via a shock absorber 15.
The connecting member 16 is
a strut attachment member 161 attached to the terminal strut 11;
A cable end fitting 162 attached to the cable body 13;
a first locking member 163 that fastens a cable end fitting 162 inserted through the inside of the tubular member 151 on one side of the tubular member 151;
a second locking member 164 that abuts the tubular member 151 (via the washer 152) on the other side of the tubular member 151 and is connected to the strut attachment member 161;
has.
Note that here, the cable end fitting 162 attached to the cable body 13 is inserted into the inside of the tubular member 151 as an example, but the cable body 13 itself is inserted into the inside of the tubular member 151 and 151 may be fastened on one side.

In this embodiment, the strut attachment member 161 is constituted by a wire rope with retaining metal fittings 1611 processed at both ends thereof.
The cable end fitting 162 is a screw end that is attached to the end of the cable body 13, and is inserted through the second locking member 164 and the tubular member 151, and at its end, the nut that is the first locking member 163 is attached (with a washer). 152). The nut 163 is for preventing slippage, and has a diameter larger than the hole in the washer 152 (or the tubular member 151).
The second locking member 164 is a bracket material, and has a hole formed therein through which the strut attachment member 161 and the cable end fitting 162 are inserted. FIG. 4 is a perspective view showing the second locking member 164. The second locking member is an elongated hole through which the wire rope 161 can be inserted, but through which the retaining metal fitting 1611 cannot be inserted, and an enlarged diameter hole portion 16411 through which the retaining metal fitting 1611 can be inserted is formed in a part of the second locking member. A long hole 1641 is provided.
Since the enlarged diameter hole 16411 is formed in the center of the elongated hole 1641, a portion through which the retaining metal fitting cannot be inserted is formed in the elongated hole 1641 on both sides of the enlarged diameter hole 16411.
The enlarged diameter hole 16411 also functions as an insertion hole through which the cable end fitting 162 is inserted. (This configuration is such that it abuts against the second locking member 164.)

Attachment of the terminal strut 11 and the cable body 13 via the shock absorber 15 by the connecting member 16 is as follows:
After winding the wire rope 161 around the terminal support 11 and inserting the retaining metal fittings 1611 at both ends into the expanded diameter hole 16411, move the wire rope 161 to the parts on both sides of the expanded diameter hole 16411 where the locking metal fittings cannot be inserted. step and
The cable end fitting 162 is inserted into the enlarged diameter hole 16411 and then through the inside of each tubular member 151 (and washer 152), and fastened with a nut (first locking member) 163. a step to prevent it from falling out;
carried out by. Note that the above steps may be performed earlier or later.
When winding the wire rope 161 around the terminal support 11, it is placed through the U-shaped hook 111. The U-shaped hook 111 of this embodiment is formed in a size that allows the locking fitting 1611 to be inserted therethrough, and is fixed (welded) to the terminal support in advance. Note that the U-shaped hook 111 may be attached to the terminal column 11 after the wire rope 161 is wound around the terminal column 11 (in this case, the U-shaped hook does not need to be able to insert the retaining metal fitting). .

The terminal strut 11 and the cable body 13 are connected via the shock absorber 15 by the connecting member 16 having the above configuration, and the tension acting on the cable body 13 is applied to the tubular member 151 of the shock absorber 15 in the axial direction thereof. be done.
Note that the connecting member is one that can connect the terminal strut 11 and the cable body 13 via the shock absorber 15 (it is configured such that the tension acting on the cable body is applied to the tubular member of the shock absorber in its axial direction). Any structure may be adopted as long as it is
FIG. 22 shows another example of the connecting member.
The example shown in FIG. 22(a) is an example in which an eye finish (Toyolock (registered trademark)) is applied to a support mounting member 161' formed of a wire rope. Further, a bracket member having the same structure as the second locking member 164 is also provided at a position between the nut 163 and the shock absorber 15. The other configurations are the same as the connection member 16 of the embodiment. The eye part made of TOYOLOCK (registered trademark) can be used by attaching it to a hook attached to a support column or a turnbuckle provided for tension adjustment.
The example shown in FIG. 22(b) is an example in which a U-bolt is used as the column attachment member 161'' and a bracket material 164' is used. A hole through which the cable end fitting 162 passes and a hole through which the U bolt 161'' passes are formed in the bracket material 164'. The loop-shaped portion formed by the U-bolt 161'' can be used by being attached to a hook attached to a support, a turnbuckle provided for tension adjustment, or the like.
In addition, according to the embodiment and the connection member shown in FIG. 22, by tightening the nut 163 to the cable end metal fitting 162, which is a threaded end, it is possible to have the same tension adjustment function as a turnbuckle. It is also possible and preferable to eliminate the need for a separate tension adjustment member such as the above).

According to the protective fence 1 of this embodiment, by providing the shock absorber 15 having the tubular member 151 equipped with the load converter 1511, the load capacity of the elastic deformation region and the energy absorption of the plastic deformation region of the load converter 1511 are provided. Both can be used effectively. For example, the static load caused by snowfall can be handled by the load capacity of the elastic deformation region (because it is an elastic region, it will return to its original state when the load from snowfall is removed, and can repeatedly perform its function), and the impact from falling rocks can be countered by the load capacity of the elastic deformation region. Energy absorption in the plastic deformation region makes it possible to obtain a high buffering effect. That is, it is highly useful as a shared fence for rockfall protection and avalanche prevention.
Furthermore, according to the shock absorbing device 15, the amount of displacement in the axial direction of the cables caused by the shock absorbing device when the buffer function is exerted can be made smaller than that of conventional shock absorbing devices, so the overhang amount of the protective fence ( An excellent effect can be obtained in that the increase in the bulge of the blocking surface that occurs when a rock falls, etc. can also be reduced.
Furthermore, the shock absorbing performance can be changed ( It is relatively easy to manufacture products with different specifications. It is possible to change the shock absorbing performance by selecting the material forming the tubular member and changing the diameter and thickness of the tubular member, but adjustment by changing the material or wall thickness is not easy (it is not possible to newly design the steel pipe itself). , because it needs to be manufactured). On the other hand, it is relatively easy to change the width W or height H of the enlarged diameter part (or reduced diameter part) or increase or decrease the number of enlarged diameter parts (or reduced diameter parts) to be formed (according to the standard). This method is suitable because it can be realized by processing steel pipes. Furthermore, the cushioning performance can be easily changed (manufacturing products with different specifications) by increasing or decreasing the number of tubular members 151 arranged in series.
In addition, according to the shock absorbing device 15, as shown by the results of the impact test described below, the peak of the load caused by the impact of falling rocks is suppressed, and the length of time the load is applied is lengthened (distributed). It is possible to obtain a good buffering effect.

(Impact test of shock absorber)
An impact test conducted on the shock absorber 15 described in the embodiment and its results will be described.
FIG. 5 shows the specifications of the tubular member used in this test.

Test method The overall situation of the test is shown in Figure 6 (photographs show the mounting parts of the hanging jig and shock absorber). A weight (1.5 ton) was attached to the gate-shaped tower using a tension bar and wire rope (7 x 7 25φ) via a hanging jig equipped with a shock absorber. The weight was lifted to a predetermined height using an air release device and then dropped, and the load and deformation of the shock absorber were confirmed when the impact was applied. Although the member (jig) that connects the shock absorber to the test device is not the connection member 16 of the embodiment itself, the structure on which the load is applied to the shock absorber is similar to the connection member 16.

Test Results A list of test results is shown in Tables 1 and 2 below. Table 1 shows the test results without a shock absorber, and Table 2 shows the test results with a shock absorber. Note that the "number of shock absorbers (pieces)" in Table 2 indicates the number of tubular members arranged in series.
Further, FIG. 7 shows a graph showing the load-time relationship at the first peak in Case 2 (implemented 3 times) (compared with Case 1 in which no shock absorber was provided) and the deformation state of each tubular member. In the photographs of each tubular member in FIG. 7, the one on the left is the one installed at the top in FIG. 6, and the one installed at the bottom (weight side) in FIG. They are numbered 1-4 in order from left).
Similarly, a graph showing the load-time relationship at the first peak in Case 3 (3 times) (compared with Case 1 in which no shock absorber was provided) and the deformation state of each tubular member are shown in Figure 8. Figure 9 shows a graph showing the load-time relationship at the first peak (compared with Case 1 in which no shock absorber was installed) and the deformation state of each tubular member. ) are numbered 1-5 in order).

Case 2 Results Discussion Similar load waveforms were observed in the three tests. The unevenness of the waveforms is also well approximated.
In three tests, an ideal waveform (uniform maximum value) was obtained.
A load reduction of approximately 85 kN was observed compared to the average value without the device.
In the three tests, the degree of deformation of the tubular member tended to be 1<2<3<4 (on the weight side).
Case 3 Results Consideration Similar load waveforms were observed in the three tests. The unevenness of the waveforms is also well approximated.
In three tests, an ideal waveform (uniform maximum value) was obtained.
A load reduction of approximately 80 to 100 kN was observed compared to the average value without the device.
In the three tests, the degree of deformation of the tubular member tended to be 1<2<3<4<5 (on the weight side).
Case 6 Results Discussion Similar load waveforms were observed in the three tests. The unevenness of the waveforms is also well approximated.
In three tests, an ideal waveform (uniform maximum value) was obtained.
A load reduction of approximately 80 to 100 kN was observed compared to the average value without the device.
In the three tests, the degree of deformation of the tubular member tended to be 1<2<3<4<5 (on the weight side).

As shown in the graphs in Figures 7 to 9, the peak load is suppressed and the length of time the load is applied is longer than when no shock absorber is provided (Case 1 and Case 4). It can be seen that the graph is trapezoidal (distributed).
As shown in the same graph, a characteristic point when the shock absorber 15 of the embodiment is used is that the peak of the load (the peak that was suppressed in the past) appears multiple times, and as a result, the timing at which the load is applied is dispersed. There is a point.
This may be caused by a plurality of tubular members arranged in series (in other words, a plurality of load conversion parts arranged in series) collapsing in order. In other words, it can be said that it has been shown that the timing of the tension applied to the rope (the length of time the tension is applied) can be controlled by increasing or decreasing the number of load converters arranged in series.
Note that, as shown in the test results, the tubular member was first crushed (plastically deformed) at the load conversion portion. In other words, "the yield point against bending load at the load conversion portion is lower than the yield point against compressive load or tensile load at other locations."

(Static load test of tubular member)
Next, a static load test (compression test on the tubular member) performed on the tubular member 151 (one) described in the embodiment and its results will be described.
In this test, in addition to the tubular member with the specifications shown in FIG. 5, a tubular member with the specifications shown in FIG. 10 was used.

Test method The implementation status of the test is shown in Figure 11. The test was conducted using a tensile testing machine, in which a rod R of Φ25 was inserted through the tubular member 151 (and washer 152), and the rod R, which was secured with a nut N, was brought into contact with the locking die D. , by pulling the rod R. The rod R itself is loosely fitted into the locking die D (not fixed to the locking die D), and by pulling the rod R to the right in FIG. 11, a compressive load is applied in the axial direction of the tubular member 151. This is the configuration (the structure in which a load is applied to the tubular member is the same as in the embodiment).
We conducted two types of tests: a repeated load test and a maximum load test.
In the repeated load test, a repeated tensile test was conducted with maximum loads of 30 kN and 40 kN. For example, 0 kN → 40 kN → 0 kN → 40 kN... was performed a total of 5 times as one set.
In the maximum load test, a maximum load tensile test was performed.
In both tests, the load meter and displacement meter were connected to a data logger to record the load and displacement amount.

Repeated Load Test Results The results of repeated load tests (conducted three times in Cases 11-1 to 11-3) on the tubular member having the specifications shown in FIG. 10 are shown in Table 3 and FIG. 12 below.
Table 3 shows the deformation state of the tubular member (change in dimensions shown in FIG. 10) before and after the test.
FIG. 12 is a graph showing changes in load and displacement, and a photograph showing the appearance of the tubular member after the test. Both the graph and the photograph show the results of Cases 11-1 to 11-3 in order from the top.
Similarly, the results of repeated load tests (conducted three times in Cases 12-1 to 12-3) on the tubular member having the specifications shown in FIG. 5 are shown in Table 4 and FIG. 13 below.

Consideration of Case 11 Results In Case 11-1, although there was some variation in the maximum displacement, there was almost no displacement after the second time and the same behavior was shown. It was determined that the cause of the difference between the graph and the amount of residual deformation after the test was due to the small gap when installing it on the testing machine.
As a result of actual measurement after the test, it was found that the displacement returned to within 0.1 mm under a multi-cycle load of 30 kN in all cases.
Consideration of Case 12 Results In all cases, although there is some waveform disturbance, the maximum displacements are quite similar. It was determined that the cause of the difference between the graph and the amount of residual deformation after the test was due to the small gap when installing it on the testing machine.
As a result of actual measurement after the test, it was found that the displacement returned to within 0.2 mm under a multi-cycle load of 40 kN in all cases.

Maximum load test results The results of the maximum load test (conducted three times in Cases 13-1 to 13-3) for the tubular member with the specifications shown in FIG. 10 are shown in Table 5 and FIG. 14 below.
Table 5 shows the deformation state of the tubular member (change in dimensions shown in FIG. 10) before and after the test.
FIG. 14 is a graph showing changes in load and displacement, and a photograph showing the appearance of the tubular member after the test. The results of Cases 13-1 to 13-3 are shown in order from the left.
Similarly, the results of repeated load tests (conducted three times in Cases 14-1 to 14-3) on the tubular member having the specifications shown in FIG. 5 are shown in Table 6 and FIG. 15 below.

Consideration of Case 13 Results In all cases, when the load exceeded 50 kN, the load did not increase and the amount of displacement increased, and it rose again from around 9 to 10 mm of displacement, showing an upward trend up to 80 kN. After exceeding 80 kN, the load was unloaded.
In all cases, deformation of the shock absorber (bulging of the enlarged diameter section, reduction in height) was observed.
Consideration of Case 14 Results In all cases, the load did not increase and the displacement increased when the load exceeded 85 kN, and it rose again from around 14 mm, showing an increasing trend up to 100 kN. After exceeding 100 kN, the load was unloaded.
In all cases, deformation of the shock absorber (bulging of the enlarged diameter section, reduction in height) was observed.

(Impact test as a protective fence)
An impact test conducted on the protective fence 1 described in the embodiment and its results will be described.
Figure 16 (and Table 7) shows the specifications of the protective fence used in this test.

Test method A frame was made from a steel member, and a specimen (protective fence) was attached so that the blocking surface was inclined at 10 degrees from the horizontal.
Align the center of the weight with the target fall position on the blocking surface using the crane and hoist it up to the specified height. After measuring the height from the blocking surface to a height of 33 m using a total station, a weight (1.69 ton) was dropped using an air release device and collided with the specimen. The speed was measured by reading the target mark on the weight with a high-speed camera. The rope tension was measured using a rod with a strain gauge, and the collision displacement of the specimen was photographed using a high-speed camera and a video camera.
The test situation is shown in Figure 17 (Figure 17(a) is a photograph of the protective fence taken from above).

Test Results A list of test results is shown in Table 8 below.
In addition, Fig. 18 shows a graph (some data is missing) showing the temporal change in the tension generated in each rope body 13 (12 wire ropes) in Case 1, and the deformation state of the protective fence after the collision with the weight. Figure 19 shows the deformed state of the shock absorber (Figure 19 mainly shows the shock absorber where deformation was observed (the shock absorber connected to both ends of the wire rope near the collision point of the weight)) .
Similarly, Fig. 20 shows a graph (some data is missing) showing the change in tension over time in each rope body 13 (12 wire ropes) in Case 2, and the deformation state of the protective fence after the collision with the weight. , FIG. 21 shows a modified state of the shock absorber.

Case 1 Results Discussion A weight energy of 558 kJ was captured.
The maximum extension of the blocking surface was 2100 mm, and the remaining height of the fence was 2300 mm.
The maximum deformation angle of the strut was 17.4° at the end strut, which is the impact span.
The shock absorbers of the wire ropes 7, 8, and 9 near the collision of the weights are also significantly deformed.
Except for the missing wire rope 8, the wire ropes 5, 6, 7, and 9 near the collision exhibited load waveforms close to a trapezoid as shown in FIG. 18. It is assumed that this is due to the effect of the shock absorber.
Comparing the deformation states of shock absorbers arranged in series, there is a tendency for the deformation to be more pronounced on the bracket side than on the column side. There is no significant difference between pillars 1 and 4.
Case 2 result discussion A weight energy of 558 kJ was captured.
The maximum extension of the blocking surface was 2000 mm, and the remaining height of the fence was 2600 mm.
The maximum deformation angle of the strut was 12.5° at the middle strut, which is the collision span.
At points 7, 8, and 9 near the weight collision, the shock absorbers were significantly deformed.
Except for the missing wire rope 8, the wire ropes 5, 6, 7, and 9 near the collision exhibited load waveforms close to a trapezoid as shown in FIG. 20. It is assumed that this is due to the effect of the shock absorber.
Comparing the deformation states of shock absorbers arranged in series, there is a tendency for the deformation to be more pronounced on the bracket side than on the column side. There is no significant difference between pillars 1 and 4.

In the embodiment, the shock absorber includes a plurality of tubular members, but the present invention is not limited to this, and the shock absorber may include only one tubular member.
Further, in the embodiment, the tubular members of the shock absorber are provided as one in series, but the present invention is not limited to this, and the tubular members may be arranged in parallel. FIG. 22(c) shows an example of such a device. In this example, the shock absorber 15 is attached to both ends of the support column attachment member 161' shown in FIG. 22(a). After inserting the bracket material 164' (similar to that shown in FIG. 22(b)) and the shock absorber 15 into both ends of the wire rope 161', the ends of the retaining fittings 1611 are processed, and the ends of the bracket material 164' are The cable end fitting 162 is passed through the cable end and secured with a nut 163 (and washer).
In FIG. 22(c), two rows are connected in parallel, but three or more rows may be connected in parallel. In addition, in FIG. 22(c), a plurality of tubular members provided in series are connected in parallel, but a plurality of tubular members are connected in parallel. Good too.

In the embodiment, the same tubular members are provided in series, but the present invention is not limited to this, and a shock absorber may be constructed by combining tubular members with different configurations.
For example, as shown in the above test results, tubular members provided in series tend to collapse in order from those provided on the cable body side (the closer the column side is, the more difficult it is to collapse). Based on this, it is recommended to ``provide a cable with a large load capacity on the side that collapses first'', and ``provide a cable with a large width (W in Figure 3(b)) of the expanded or contracted diameter part on the load acting side (the side of the cable body). such as ``provided on the side farthest from the load acting side (rope body side)'' or ``provide the enlarged diameter part or reduced diameter part with a large height (H in Figure 3 (b)) on the side farthest from the load acting side (rope side).'' It may be something that does the following.

In the embodiment, an example is given in which a compressive load is applied to the tubular member of the shock absorber in the axial direction, but the present invention is not limited to this, and a structure in which a tensile load is applied in the axial direction is exemplified. It may also be something that does.
Further, in the embodiment, one tubular member is provided with only one load converting portion, but the present invention is not limited to this, and a plurality of load converting portions are provided in one tubular member. It may be something that is currently in use.

In the embodiment, a shock absorber is provided at the connection point between the terminal strut and the cable body, but the present invention is not limited to this.
For example, a shock absorber may be provided at the connection point between the intermediate strut and the cable. FIG. 23 shows an example of this. By using the connecting member 16 described in the embodiment as is, the cables 13 can be connected via the shock absorbers 15 on both sides of the intermediate strut.
Furthermore, a buffer device may be provided in the middle of the cables (two cables may be connected via a buffer device). For example, in FIG. 23, by connecting the connecting members 16 to each other without using the intermediate struts 12, it is possible to connect the two cables through the shock absorber. Moreover, by using a connecting member as shown in FIG. 22, two cables can be connected via a shock absorber.

In the embodiment, the load conversion section is formed as an enlarged diameter section, but the present invention is not limited to this. The load conversion section may be formed by a reduced diameter section. Further, the expanded diameter portion and the reduced diameter portion are not limited to an arcuate shape, and may have any shape. In addition, the position and range in which the load conversion section is formed can be arbitrary.
FIG. 24 shows an example of this.
The tubular member 151' shown in FIG. 24(a) is an example in which the load conversion section is formed by a reduced diameter section 1511'.
The tubular member 151'' in FIG. 24(b) is an example in which the load converting portion is formed by tapered portions (enlarged diameter portions) 1511'' formed at both ends of the tubular member in the axial direction.
The tubular member 151''' shown in FIG. 24(c) is an example in which the load converting section is formed by a stepped part (enlarged diameter part) 1511''' formed in the tubular member.
The tubular member 151'''' in FIG. 24(d) is an example of one that is configured only with a load converting portion 1511'''' without providing a straight tubular portion.
Note that it is also possible to form both an enlarged diameter portion and a reduced diameter portion in one tubular member.
It can also be said that the difference is whether the enlarged diameter part or the reduced diameter part is viewed as a reference (for example, in FIG. difference), in that sense there is no conceptual difference between the two.

In the embodiment, the enlarged diameter portion is provided all around the circumference, but the present invention is not limited to this. For example, a portion of the expanded diameter portion (or reduced diameter portion) may be cut to form an intermittent expanded diameter portion (or reduced diameter portion).
For example, by forming one or more holes or notches in the enlarged diameter part (or reduced diameter part), it is possible to change the load capacity of the elastic region and the cushioning performance (manufacturing products with different specifications). It is.

In the embodiment, a steel pipe with a circular cross section is used as an example of the tubular member, but the present invention is not limited to this. For example, it is possible to use a tubular member with an arbitrary cross-sectional shape, such as a polygon (the "tubular member" includes a tubular member with an arbitrary cross-sectional shape).

In the embodiment, a common fence for rockfall protection and avalanche prevention is used as an example of the protective fence, but the present invention is not limited to this. For example, it may of course be used as a protection fence against falling rocks or a protection fence against collapsed earth and sand (used in non-snowy areas).

1. ．． ．． Protective fence (shared fence for rockfall protection and avalanche prevention)
11. ．． ．． Terminal support 12. ．． ．． Intermediate strut 13. ．． ．． Chord body 15. ．． ．． Buffer device 151. ．． ．． Tubular member 1511. ．． ．． Load conversion part (expanded diameter part)
16. ．． ．． Connection member 161. ．． ．． Post attachment member 1611. ．． ．． Retaining metal fitting 162. ．． ．． Cable end fitting 163. ．． ．． First locking member 164. ．． ．． Second locking member 1641. ．． ．． long hole
16411. ．． ．． Expanded hole

Claims (20)

Multiple pillars erected,
A cable stretched between the struts,
A shock absorber provided at a connection point between the strut and the cable body or in the middle of the cable body, the shock absorber having one or more tubular members;
Equipped with
The shock absorber is configured such that the tension acting on the cable is applied to the tubular member in its axial direction, thereby absorbing at least a portion of the compressive load or tensile load applied in the axial direction of the tubular member. , a protective fence equipped with a load conversion section that applies it as a bending load. The protective fence according to claim 1, wherein the load conversion section is configured by an enlarged diameter section or a reduced diameter section provided on the tubular member. The protective fence according to claim 2, wherein the tubular member is formed with a plurality of the enlarged diameter portions, the plurality of diameter reduced portions, or both. The protective fence according to any one of claims 1 to 3, wherein the plurality of tubular members are arranged in series. The protective fence according to any one of claims 1 to 3, wherein in the tubular member, the yield point against bending load at the load converting portion is lower than the yield point against compressive load or tensile load at other locations. A connection member that connects the support column and the cable body via the buffer device,
a strut attachment member attached to the strut;
a first locking member that fastens the cable inserted through the one or more tubular members or the cable end fitting attached to the cable on one side of the one or more tubular members;
a second locking member that abuts the one or more tubular members directly or through another member on the other side of the one or more tubular members and is connected to the strut attachment member;
The protective fence according to any one of claims 1 to 3, comprising a connecting member having: The strut attachment member is a wire rope whose end is treated with a retaining fitting,
The second locking member is an elongated hole through which the wire rope can be inserted, and through which the retaining metal fitting cannot be inserted, and an enlarged diameter hole portion through which the retaining metal fitting can be inserted is formed in a part of the elongated hole. The protective fence according to claim 6, comprising an elongated hole. The ends of the retaining metal fittings are processed at both ends of the wire rope,
Since the enlarged diameter hole is formed in the center of the elongated hole, portions through which the retaining metal fitting cannot be inserted are formed in the elongated holes on both sides of the enlarged diameter hole. The protective fence according to claim 7, wherein the diameter hole portion also functions as an insertion hole through which the cable body or a cable end fitting attached to the cable body is inserted. A method for assembling the connecting member in the protective fence according to claim 8, comprising:
The wire rope is wound around the support, and the retaining metal fittings at both ends are inserted into the enlarged diameter hole, and then moved to the portions on both sides of the enlarged diameter hole where the preventing fittings cannot be inserted. step and
The cable body or the cable end fitting attached to the cable body is inserted into the enlarged diameter hole, and then passed through the inside of the one or more tubular members and fastened by the first locking member. step and
Assembling method. A buffer device that buffers the tension acting on the cable body,
comprising one or more tubular members to which tension acting on the cord body is applied in the axial direction;
A shock absorber comprising a load converter that applies at least a part of the compressive load or tensile load applied in the axial direction of the tubular member as a bending load. The shock absorbing device according to claim 10, wherein the load conversion section is configured by an enlarged diameter section or a reduced diameter section provided in the tubular member. The shock absorber according to claim 11, wherein the tubular member is formed with a plurality of the enlarged diameter portions, the plurality of diameter reduced portions, or both. The shock absorber according to any one of claims 10 to 12, wherein the plurality of tubular members are arranged in series. 13. The shock absorber according to claim 10, wherein in the tubular member, a yield point against a bending load at the load conversion portion is lower than a yield point against a compressive load or a tensile load at other locations. A method for manufacturing the protective fence according to claim 3, comprising:
A method for manufacturing a protective fence, wherein the buffering performance of the shock absorber is changed by changing the number of the enlarged diameter portions or the reduced diameter portions. A method for manufacturing the protective fence according to claim 4, comprising:
A method for manufacturing a protective fence, comprising changing the buffering performance of the buffering device by changing the number of the tubular members. A method for manufacturing the protective fence according to claim 2 or 3, comprising:
A method for manufacturing a protective fence, wherein the buffering performance of the shock absorber is changed by changing the width or height of the expanded diameter portion or the reduced diameter portion. A method for manufacturing the shock absorber according to claim 12, comprising:
A method of manufacturing a shock absorber, wherein the shock absorbing performance is changed by changing the number of the enlarged diameter portions or the reduced diameter portions. A method for manufacturing the shock absorber according to claim 13, comprising:
A method for manufacturing a shock absorber, wherein the shock absorbing performance is changed by changing the number of the tubular members. A method for manufacturing the shock absorber according to claim 11 or 12, comprising:
A method of manufacturing a shock absorber, wherein the shock absorbing performance is changed by changing the width or height of the enlarged diameter portion or the reduced diameter portion.

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