JP6297375B2 - Rock fall prevention device - Google Patents

Description

  The present invention relates to a rock fall prevention device.

A rock fall prevention device is known which is installed on the side of a road or on a hillside slope to prevent rock fall on the road. Some rock fall prevention devices have improved durability by absorbing the energy of rock fall.
For example, when a tension is applied to a rope that supports a rockfall prevention net by falling rocks, the rope extends, and there is a thing that absorbs the energy of falling rocks with energy necessary for this elongation (see, for example, Patent Document 1).
Moreover, when a falling rock trapping material is provided on the flexible wire, and the tension is applied to the wire through the falling rock trapping material by the falling rock, the energy of the falling rock is reduced by the sliding friction between the holding plate that holds the wire. Some absorb (for example, refer to Patent Document 2).
In addition, a shock absorber is provided on the wire rope arranged in a lattice shape, and when a certain level of tension acts on the shock absorber, the wire rope moves while deforming into a corrugated shape, and rock falls with the energy required for this deformation and movement. (For example, refer to Patent Document 3).

Japanese Patent No. 3458134 Japanese Patent No. 4874925 JP 2012-77496 A

  However, since the energy of rock fall that can be absorbed by the deformation of the rope as described above and sliding friction between the rope and the sandwiching plate is not sufficient, by increasing the rigidity by increasing the rope and rock fall trapping material, Durability was improved. Therefore, there are problems that the apparatus becomes heavy and the manufacturing cost increases.

  Then, this invention is made | formed in view of the said subject, and it aims at providing the falling rock prevention apparatus which can absorb much energy of falling rocks and can improve durability, without enlarging apparatus itself. And

In order to solve the above problems, the present invention provides a rockfall catching portion that catches rockfalls, a support portion that supports the rockfall catching portion, and an energy absorption mechanism that absorbs the energy of rockfall that acts on the rockfall catching portion. A rock fall prevention device provided, wherein the energy absorption mechanism is connected to the support portions and a plurality of guide portions disposed at positions deviating from the extended lines of the support portions, and is in contact with the guide portions. It possesses a arranged plate, wherein the plurality of guiding portions is characterized in that it is arranged offset alternately in the vertical direction from the extended line of the supporting portion.

  As one aspect of the present invention, it is preferable that the energy absorption mechanism is provided in the support portion.

  As one aspect of the present invention, it is preferable that the guide portion includes a core material and a roller that is rotatably provided on the same axis as the core material outside the core material.

  As one aspect of the present invention, it is preferable that the plate material is disposed so as to be in surface contact with the roller.

  As one aspect of the present invention, it is preferable that the energy absorption mechanism has a housing in which the guide portion is provided.

  As one aspect of the present invention, the energy absorbing mechanism is provided at one end of the plate material, and when the plate material moves a predetermined distance toward the falling rock catching portion, the energy absorbing mechanism is locked to the housing and moves the plate material. It is preferable to have a stopper that regulates the above.

  As one aspect of the present invention, the support portion is attached with the falling rock catching portion, and at least one end is connected to the plate member, one end is fixed, and the other end is connected to the housing. It is preferable to have a second support member.

  As one aspect of the present invention, it is preferable that the first support member and the second support member are arranged so as to extend on the same straight line.

  According to the present invention, it is possible to improve the durability of the rock fall prevention device by absorbing a large amount of rock fall energy without increasing the size of the support portion and the rock fall capturing portion more than necessary.

It is a perspective view which shows the falling rock prevention apparatus attached to the ground. It is sectional drawing of an energy absorption mechanism. It is a side view of an energy absorption mechanism. It is a graph which shows the relationship between the tension | tensile_strength which acts on a support part, and elapsed time when a falling rock is captured. It is a graph which shows the relationship between the tension | tensile_strength which acts on a support part, and the displacement amount of a support part when falling rocks are caught.

  Preferred embodiments of the present invention will be described with reference to the drawings. In addition, embodiment shown below is one illustration and can take various embodiment in the scope of the present invention.

<Configuration of rock fall prevention device>
FIG. 1 is a perspective view showing a rock fall prevention device 100 attached to the ground G. FIG.
As shown in FIG. 1, the rock fall prevention device 100 is installed on a ground G such as a roadside or a hillside slope, and prevents rock fall on the road.
The rockfall prevention device 100 includes a rockfall catching section 1, a support section 2, and an energy absorption mechanism 3.

(Falling rock catcher)
The falling rock capturing unit 1 captures the falling rock when the falling rock is generated. The falling rock catcher 1 is formed, for example, by knitting a steel wire rope in a lattice shape and installing a net. The falling rock capturing part 1 is formed in a substantially rectangular shape, and a plurality of supporting parts 2 are stretched around the falling rock capturing part 1. The falling rock capturing unit 1 is provided with a support for introducing falling rocks into the falling rock capturing unit 1 (not shown).

(Support part)
The support part 2 supports the falling rock capturing part 1. The support part 2 is formed of, for example, a steel wire rope. One end of the support portion 2 is fixed to the ground G by an anchor member A.
The support portion 2 includes a first support member 21 and a second support member 22, and one end of the second support member 22 is fixed to the ground G by an anchor member A. Note that one end of the second support member 22 is not limited to being fixed to the ground G, but is concrete placed on the site, steel material installed on the ground (for example, H-shaped steel, square steel pipe, round steel pipe) Etc.).
One end of the first support member 21 is attached to the falling rock trap 1, the other end is connected to the energy absorption mechanism 3, and the other end of the second support member 22 is connected to the energy absorption mechanism 3. That is, the energy absorbing mechanism 3 is provided between the first support member 21 and the second support member 22.

(Energy absorption mechanism)
FIG. 2 is a cross-sectional view of the energy absorption mechanism 3, and FIG. 3 is a side view of the energy absorption mechanism 3.
The energy absorbing mechanism 3 absorbs the energy of falling rocks that acts on the falling rock capturing unit 1. The energy absorbing mechanism 3 is connected to the first support member 21 and the second support member 22, and reduces the tension applied to the support portion 2 by the rock fall energy acting on the fall rock catching portion 1.

The energy absorbing mechanism 3 includes a guide portion 4, a plate material 5, a housing 6, and a stopper 7.
The guide unit 4 is provided in the housing 6. As shown in FIG. 3, the housing 6 is formed in a rectangular cylindrical shape by connecting the groove sides of the groove steels 61, 61 formed in a substantially U shape in a side view so as to face each other. . The housing 6 is assembled by inserting bolts 41 from one channel steel 61 so as to penetrate both channel steels 61 and screwing nuts 42 to the bolts 41 protruding from the other channel steel 61. .
In the housing 6, the bolt 41 is inserted through a cylindrical roller 43 accommodated in the housing 6, and the roller 43 is provided on the outer side of the bolt 41 so as to be rotatable on the same axis as the bolt 41. . That is, the bolt 41 functions as a core material, and the bolt 41 and the roller 43 constitute the guide portion 4 that guides the plate material 5.
As shown in FIG. 2, the bolt 41 is inserted into the grooved steel 61 at a position deviated from the center in the height direction within the housing 6 by a predetermined distance. More specifically, a plurality of guide portions 4 are provided in the housing 6, and are arranged at positions off the extended lines of the support members 21 and 22. The guide portion 4 is disposed in a zigzag manner in the housing 6 with respect to the extension lines of the support members 21 and 22. That is, in FIG. 2, the guide part 4 is arrange | positioned so that it may mutually shift | deviate to the up-down direction from the extended line of each support member 21 and 22. In FIG. One of the guide portions 4 is provided at a substantially center in the height direction of the housing 6, and the guide portion 4 is connected to the second support member 22. As a result, the housing 6 and the second support member 22 are connected.

The plate material 5 is formed of, for example, a steel flat plate material, and is disposed in the housing 6 so that any one surface of the plate material 5 comes into contact with one guide portion 4. That is, the plate material 5 is in surface contact with the surface of the roller 43. The plate member 5 is connected to the first support member 21 and is formed to be pulled by the first support member 21 when a large tension acts on the first support member 21 and move by the tensile force. ing.
The plate member 5 is connected to one end of the first support member 21 via a connection fitting (shackle or the like) 23. Here, the plate member 5 is drawn to the outside of the housing 6 from substantially the center in the height direction of the housing 6, and is connected to the first support member 21 at this position. Therefore, the first support member 21 and the second support member 22 are arranged so as to extend on the same straight line.
The plate 5 is disposed along the guide portion 4 on the way from one end connected to one end of the first support member 21 to the other end. As a result, the plate 5 is bent a plurality of times. It has become.

A stopper 7 is provided at the other end of the plate 5. The stopper 7 includes a bolt 71 that penetrates the plate material 5 in the thickness direction, and a nut 72 that is fastened by sandwiching the plate material 5 with the bolt 71. By providing such bolts 71 and nuts 72 at the other end of the plate material 5, this portion becomes considerably larger than the thickness of the plate material 5, so when the plate material 5 moves a predetermined distance toward the falling rock capturing part 1, It functions as a stopper 7 that is locked between the housing 6 and the guide portion 4 and restricts further movement of the plate 5.
In addition, by changing the quantity, arrangement, and plate thickness of the guide member 4, the amount of rock fall energy acting on the fall rock catching portion 1 is absorbed, the reduction amount of tension acting on the first support member 21, the plate material 5 can be adjusted.

<Energy absorption effect of rock fall prevention device>
FIG. 4 is a graph showing the relationship between the tension acting on the support unit 2 and the elapsed time when trapping rocks, and FIG. 5 is the graph showing the tension and support acting on the support unit 2 when trapping rocks. 3 is a graph showing a relationship with a displacement amount of a part 2;
As shown in FIG. 4, in the rock fall prevention device that does not include the energy absorbing mechanism 3, the tension acting on the support portion 2 increases as time elapses from immediately after falling rock capture, and the maximum tension of Pmax acts. . At this time, the support part 2 and the anchor member A might be damaged.
Further, as shown in FIG. 5, when looking at the displacement of the support portion 2, the support portion 2 continues to be displaced until the tension reaches Pmax as time elapses after catching the falling rock, that is, when the tension reaches Pmax, that is, When the displacement reaches δ2, the support portion 2 or the anchor member A may be damaged.

On the other hand, in the rock fall prevention device 100 provided with the energy absorbing mechanism 3, the tension acting on the support portion 2 increases as time elapses immediately after the rock fall capture, but when the tension Po reaches a certain tension Po, Since tension is used for deformation and movement, the tension acting on the support portion 2 does not rise from Po. Therefore, the peak cut can be achieved by the tension difference Pc = Pmax−Po. In FIG. 4, the time t1 during which the tension Po is kept constant is the time when the plate 5 has moved.
The displacement of the support portion 2 is also displaced until the tension reaches Po, and if the displacement at that time is δ1, the displacement thereafter becomes δ3 until the stopper 7 is locked to the housing 6, that is, the displacement. The plate material 5 moves up to this point. Therefore, the movement amount Lw of the support portion 2 is Lw = δ3−δ1.

In addition, the energy absorption amount E1 of the rock fall prevention device not provided with the energy absorption mechanism 3 is
E1 = 1/2 × Pmax × δ2
And
The energy absorption amount E2 of the rock fall prevention device 100 provided with the energy absorption mechanism 3 is:
E2 = 1/2 * Po * [delta] 1 + Po * ([delta] 3- [delta] 1)
= 1/2 × Po × δ1 + Po × Lw
It becomes.

As described above, according to the rockfall prevention device 100 described above, when rockfall occurs and collides with the rockfall catching portion 1, the kinetic energy of the rockfall acts on the rockfall catching portion 1 and tries to break through the rockfall catching portion 1. To do. Along with this, the first support member 21 that supports the rockfall catching portion 1 is pulled by the rockfall catching portion 1, tension is applied, and the plate member 5 connected to the first support member 21 is also pulled. Here, since the plate material 5 is guided by the guide portion 4, the plate material 5 is deformed and moved in a zigzag manner along the guide portion 4. Since tension is used for this deformation and movement, the tension acting on the first support member 21 is reduced, and as a result, breakage of the support portion 2 can be prevented.
Therefore, it is possible to improve the durability of the rock fall prevention device 100 by absorbing a large amount of rock fall energy without increasing the rigidity of the rock fall prevention device by increasing the configuration as in the prior art.
Moreover, since the guide part 4 has the roller 43, the tension | pulling of the board | plate material 5 can be made smooth.
Further, since the plate material 5 is disposed so as to be in surface contact with the roller 43, the frictional force generated between the two increases, and the energy absorption effect can be enhanced.
In addition, since the stopper 7 is provided, the first support member 21 and the energy absorbing mechanism 3 are not separated from the plate member 5 by deviating from the housing 6. Even if a large tension acts on 21, falling rocks do not jump out of the falling rock catching portion 1.
Moreover, since the 1st supporting member 21 and the 2nd supporting member 22 are extending on the same straight line, rotation of the energy absorption mechanism 3 by falling rocks can be suppressed as much as possible.
Moreover, the tension | tensile_strength which acts on the support part 2 can be adjusted by changing the material, board thickness, width | variety of the board | plate material 5, the position of the guide part 4, and quantity.

<Others>
In addition, this invention is not restricted to the said embodiment, In the range which does not exceed the range of this invention, it can change suitably. For example, it is not necessary to divide the support part into two parts, and a part of the casing of the energy absorbing mechanism may be fixed to the ground or the like with an anchor member. Further, it is not necessary to provide the energy absorbing mechanism in all the support portions, and there is no problem even if the energy absorption mechanism is provided only in a place where a large tension acts on the support portion. Moreover, if a guide part guides so that a board | plate material may be bent, arrangement | positioning and quantity can be changed arbitrarily. In addition, there is no problem with the stopper as long as the end of the plate is simply bent to a sufficiently larger end than the thickness of the plate.

DESCRIPTION OF SYMBOLS 1 Falling rock capture part 2 Support part 3 Energy absorption mechanism 4 Guide part 5 Plate material 6 Housing | casing 7 Stopper 21 1st support member 22 2nd support member 41 Bolt (core material)
43 Roller 71 Bolt 72 Nut 100 Falling rock prevention device G Ground A Anchor member

Claims (8)

A rockfall catcher that catches rockfalls;
A support part for supporting the falling rock capturing part;
A rockfall prevention device comprising an energy absorption mechanism that absorbs the energy of rockfall acting on the rockfall catching portion,
The energy absorption mechanism is:
A plurality of guide portions arranged at positions deviating from the extension line of the support portion;
A plate member connected to the support portion and disposed so as to abut each guide portion;
I have a,
The rock fall prevention device, wherein the plurality of guide portions are alternately displaced in the vertical direction from the extended line of the support portion .   The rock fall prevention device according to claim 1, wherein the energy absorption mechanism is provided in the support portion.   The rock fall prevention device according to claim 1 or 2, wherein the guide portion includes a core material and a roller rotatably provided on a coaxial line with the core material outside the core material.   The rock fall prevention device according to claim 3, wherein the plate member is disposed so as to be in surface contact with the roller.   The rock fall prevention device according to any one of claims 1 to 4, wherein the energy absorption mechanism includes a housing in which the guide portion is provided.   The energy absorbing mechanism has a stopper provided at one end of the plate material and locked to the housing to restrict the movement of the plate material when the plate material moves a predetermined distance toward the falling rock catching portion. The rock fall prevention device according to claim 5. The support part has the first support member to which the falling rock capturing part is attached and at least one end connected to the plate member;
A second support member having one end fixed and the other end coupled to the housing;
The rock fall prevention device according to claim 5 or 6, characterized by comprising:   The rock fall prevention device according to claim 7, wherein the first support member and the second support member are arranged so as to extend on the same straight line.

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