JP3825218B2 - Mesh structure for rockfall prevention - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rock fall prevention net-like structure for preventing a fall rock from falling to a road or a building when a fall rock occurs on a mountain slope.
[0002]
[Prior art]
Because there is a risk of falling rocks on the roads in the mountains, structures to prevent falling rocks are installed on slopes and cliffs on the mountain side to protect passers-by from falling rocks. For example, Japanese Patent Laid-Open No. 7-42117 discloses a rock fall prevention net-like structure that receives rock fall with a net to prevent the stone from falling to the road.
[0003]
[Problems to be solved by the invention]
However, in the conventional net structure for rockfall prevention, when an excessive amount of rockfall is received, the net is broken or the support structure such as the support and the anchor collapses, and the rockfall reaches the road. There is a risk of serious damage. In particular, if there is a huge rock fall, there is a risk of breaking through in an instant, and it cannot be guaranteed that safe traffic on mountain roads can be guaranteed. For this reason, there is a demand for practical use of a rock fall prevention structure that is not easily broken through even when it receives a huge rock fall.
[0004]
The present invention has been made in order to solve the above-described problem, and the net is not broken when subjected to the impact of falling rocks, and the support structure members such as the columns and anchors can be effectively prevented from collapsing. An object is to provide a net-like structure for preventing falling rocks.
[0005]
[Means for Solving the Problems]
A net-like structure for rockfall prevention according to the present invention is a net for catching rockfall, a cable that is directly or indirectly fixed to the ground, and supports the net so as to expand, and supports and supports the cable together with the net. A plurality of struts fixed directly or indirectly to the ground and attached to at least one of the struts, when the net receives a rock fall, it displaces together with the net to absorb impact energy from the rock fall and propagate to the net A buffer portion that relieves impact force, and the buffer portion wraps and holds at least one of the cords so as to be slidable, and does not move the end of the grip to the column. a stopper secured to, and the slack portion which gave slack on at least one end portion of the cord between the stopper to the grip, contracture half for gently constraining the slack portion in said post Characterized by comprising a member.
[0007]
Moreover, it is preferable that the said buffer part is provided in the left-right paired vertical cord which suspends and supports the said net | network above.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, various preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[0009]
(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.
[0010]
The rock fall prevention net-like structure 3 of the first embodiment is provided on the slope 1 on the mountain side of the road 2 as shown in FIGS. 1 and 2. A pair of struts 5 are driven substantially perpendicular to the slope 1 at substantially the same height of the slope 1. These pair of support | pillars 5 consist of a pocket type H-section steel pile material provided with the pin volt | bolt and the shackle, and the traps are provided in the equal pitch space | interval. The two struts 5 support the suspension lateral cord 6 and the suspension longitudinal cord 7, respectively, and the mesh 4 is supported by the suspension lateral cord 6 and the suspension longitudinal cord 7 so as to suspend the curtain.
[0011]
Both ends of the suspension transverse cable 6 are embedded and fixed to the slope 1 with anchor metal objects 10. A large number of suspensions 6 a are attached to the suspension lateral cable 6 from one support column 5 to the other support column 5 at equal pitch intervals. A vertical wire 4a of the net 4 is connected to each of the large number of hanging tools 6a.
[0012]
As shown in FIG. 2, the mesh 4 is suspended from one support column 5 to the other support column 5 so that the curtain is suspended by the suspension lateral cable 6, and the lower end of the mesh 4 reaches the vicinity of the road 2. ing. It should be noted that turnbuckles 11 are respectively attached to appropriate positions near both ends of the suspension lateral cable 6 so that the tension of the suspension lateral cable 6 can be adjusted.
[0013]
The upper ends of the pair of left and right suspension vertical cords 7 are embedded and fixed to the slope 1 by anchor metal objects 10. The pair of suspended longitudinal cords 7 support the upper left and right ends of the net 4. A buffer portion 20 for relaxing and absorbing the impact energy of falling rocks is provided at the end of the suspended vertical cord 7. It should be noted that turnbuckles 11 are respectively attached to appropriate positions near the upper ends of the suspension vertical cords 7 so that the tension of the suspension vertical cords 7 can be adjusted.
[0014]
In order to give the net 4 tension in the lateral direction, a plurality of pairs of lateral cords 8 are attached to the left and right sides of the net 4 at appropriate intervals. The end of each lateral cord 8 is embedded and fixed to the inclined surface 1 by an anchor bolt 9.
[0015]
In the single span curtain net of the present embodiment, the distance from one strut 5 to the other strut 5 is about 30 m, and the length from the upper end to the lower end of the net 4 is about 20 m. The mesh 4 has a mesh size of 50 mm × 50 mm.
[0016]
Next, the buffer portion 20 will be described with reference to FIGS.
[0017]
As shown in FIG. 3, the buffer portion 20 is provided at the end 7 a of the suspended vertical cord, and loosely restrains the suspended vertical cord 7 to the column 5 with a margin in the end portion 7 a. The buffer portion 20 includes a support fitting 21 (lot) with a nut 24 fastened to the web 5a of the column 5 made of an H-shaped steel pile material, and a grip that is wound around an appropriate position of the longitudinal cord end portion 7a and connected to the support fitting 21 26, a stopper 27 with a washer 25 cast integrally with the longitudinal end portion 7a and attached to the strut web 5a, and a wire 28 that weakly restrains an appropriate position of the longitudinal cord end portion 7a to the strut web 5a. . The length of the longitudinal cord end portion 7a from the grip 26 to the wire 28 is preferably about 0.5 to 5 m, and more preferably 1 to 3 m. The stopper 27 is formed by casting and integrating a zinc-based alloy at the end portion of the longitudinal cord end portion 7a.
[0018]
As shown in FIGS. 4 and 5, a round thimble 22 supported by a pin 23 is provided at the tip of the support fitting 21, and an ice ply portion of a winding grip 26 is wound around the round thimble 22. The grip 26 is formed of a belt-like body formed by bundling a large number of thin wires, and has a certain degree of flexibility so that it can be easily wound around the longitudinal cord end portion 7a. Note that a non-slip agent containing glass powder is applied to the surface of the grip 26 to increase the frictional resistance between the grip 26 and the round thimble 22.
[0019]
Next, the operation when the net-like structure 3 receives a falling rock will be described with reference to FIGS. 6 and 7.
[0020]
When the net 4 receives the falling rock, the impact load is distributed and transmitted from the net 4 to each of the longitudinal cord 7 and the lateral cords 6 and 8. Due to the propagation of the impact load, a large tension is suddenly generated in the longitudinal cord 7, whereby the wire 28 of the buffer portion 20 is detached, and the longitudinal cord end portion 7 a as a slack portion supported semi-constrained is brought into an unconstrained state. The cable end 7a is pulled out while rubbing against the grip 26. As shown in FIG. 6, the longitudinal cord 7 extends downward, and the mesh 4 is displaced while receiving the resistance of the lateral cords 6, 8. Therefore, the impact energy of the falling rock is greatly relaxed and absorbed. When the slack portion of the longitudinal cord end 7a is pulled out while receiving the resistance of the grip 26, the withdrawal of the longitudinal cord end portion 7a is stopped by the action of the stopper 27, and the tension is applied to the longitudinal cord 7. As shown in FIG.
[0021]
According to the net structure for rockfall prevention of the present embodiment, the rockfall is received without the net breaking through instantaneously, and the road 2 is not damaged by the rockfall. Further, the impact energy of the falling rock is effectively absorbed and relaxed by the displacement of the longitudinal cord and the transverse cord together with the net, so that the support structure members such as the support column and the anchor are prevented from collapsing.
[0022]
In the above embodiment, an example of a single-span curtain net has been described as a rock fall prevention net-like structure, but the present invention is not limited to this, and the same net-like structure is arranged in parallel on the left and right. The present invention can also be applied to a multi-span curtain net.
[0023]
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS.
[0024]
As shown in FIGS. 8 to 10, the rock fall prevention net-like structure 30 of the second embodiment is a structure made of a protective fence provided under a cliff near the road. This protective fence-type rock fall prevention net-like structure 30 includes a base steel plate 31, a concrete base 32, a plurality of support pillars 33, 35, a net 34, a lateral cable 37, and a vertical cable 38. . Although only one is shown in the figure, the main support columns 33 are provided on both sides of the base 32, respectively. A plurality of intermediate struts 35 are provided between one main strut 33 and the other main strut 33, for example, at intervals of about 5 m. The lower portions of these intermediate struts 35 are inserted into holes in the base 32, and the intermediate struts 35 are fixed to the base 32 by filling a gap between the intermediate struts 35 and the base 32 with mortar 36.
[0025]
A plurality of lateral cords 37 are provided between the columns 33 and 35, and a net 34 is stretched between the lateral cords 37 and the longitudinal cords 38. The net 34 is attached to the horizontal cable 37 and the vertical cable 38 by a locking fitting (not shown). Longitudinal cords 38 are provided at intervals of about 1 m. The main strut 33 is made of an H-shaped steel pile material, and the support fitting 21 is fastened to the web of the main strut 33 with a nut 24 via a washer 25.
[0026]
In the net-like structure 30 of the present embodiment, the distance from one main support 33 to the other main support 33 is about 3 m, the length from the upper end to the lower end of the net 34 is about 1.5 m, and the height of the base 32 is About 2.5 m. The mesh 34 has a mesh size of 50 mm × 50 mm.
[0027]
Next, the buffer 40 will be described with reference to FIGS. 11 and 12.
[0028]
As shown in FIG. 11, the buffer portion 40 is provided at the end portion 37a of the lateral cord, and loosely restrains the lateral cord 37 to the main column 33 with a margin in the end portion 37a. The buffer portion 40 includes a support bracket 21 with a nut 24 fastened to a web of a main column 33 made of an H-shaped steel pile material, a grip 26 wound around a proper position of a lateral end portion 37a and connected to the support bracket, A stopper 41 integrally cast on the end portion 37 a and a fixing metal 42 for fastening the stopper 41 to the flange of the support column 33 with a screw 43 are provided. The length of the lateral cord end portion 37a from the grip 26 to the fixing bracket 42 is preferably 0.5 to 5 m, and more preferably 1 to 3 m. The stopper 41 is formed by integrating a zinc-based alloy with a press mold using a press die at the end portion of the lateral cord end portion 37a.
[0029]
Next, an operation when the above-described network structure 30 receives a falling rock will be described with reference to FIG.
[0030]
When the net 34 receives the falling rock, the impact load is distributed and transmitted from the net 34 to each of the lateral cable 37, the longitudinal cable 38, and the columns 33 and 35. Due to the propagation of the impact load, a large tension is suddenly generated in the lateral cord 37, whereby the fixing bracket 42 of the buffer portion 40 is detached, and the lateral cord end portion 37a that is weakly restrained and supported is pulled out while rubbing against the grip 26. Since the net 34 is displaced while the lateral cord 37 receives the resistance of the grip 26 and the columns 33 and 35, the impact energy of the falling rock is greatly relaxed and absorbed. If the loosened portion of the lateral cord end 37a is pulled out while receiving resistance, the withdrawal of the lateral cord end portion 37a is stopped by the action of the stopper 41, and the weight of the falling rock in the state where tension is applied to the lateral cord 37 balance.
[0031]
According to the rock fall prevention net-like structure of the present embodiment, the fall rock is received without the net breaking through instantaneously, and the fall rock damage is not affected on the road. Moreover, since the impact energy of the falling rock is effectively absorbed and relaxed by the displacement of the lateral cord together with the net, collapse of the support structure member such as the support column is prevented.
[0032]
In addition, although the said embodiment demonstrated the case where the structure of this invention was used beside the road along a mountain, this invention is not restricted only to this, In order to protect other structures, such as a warehouse, from falling rocks. Can be used.
[0033]
【The invention's effect】
According to the present invention, falling rocks are received without instantaneously breaking through the net, and falling roads are not affected by falling rocks.
[0034]
Moreover, since the impact energy of the falling rock is effectively absorbed and relaxed by the displacement of the support rope together with the net, the support structure member such as the support column is prevented from collapsing.
[Brief description of the drawings]
FIG. 1 is a front view showing a fallen rock prevention net-like structure (curtain net) according to a first embodiment of the present invention.
FIG. 2 is a side view showing a rock fall prevention net-like structure according to the first embodiment of the present invention.
FIG. 3 is an enlarged view of a main part showing a buffer part of the net-like structure for rockfall prevention according to the first embodiment of the present invention.
FIG. 4 is an exploded view showing members constituting the buffer portion of the first embodiment.
FIG. 5 is an exploded view showing members constituting the buffer portion of the first embodiment.
FIG. 6 is a schematic front view showing the net-like structure of the first embodiment when it is displaced in response to falling rocks.
FIG. 7 is a front view showing a buffer portion when it is displaced due to falling rocks.
FIG. 8 is a front view showing a rock fall prevention net-like structure (fall rock protection fence) according to a second embodiment of the present invention.
FIG. 9 is a side view showing a rock fall prevention net-like structure according to a second embodiment.
FIG. 10 is a perspective view showing a rock fall prevention net-like structure according to a second embodiment.
FIG. 11 is a perspective view showing a buffer portion according to a second embodiment.
FIG. 12 is a partially enlarged view showing a rope end fastening portion of the buffer portion.
FIG. 13 is a perspective view showing a rock fall prevention net-like structure according to a second embodiment when the rock fall is received and displaced.
[Explanation of symbols]
3, 30 ... Network structure for rock fall prevention,
4,34 ... net,
5, 33, 35 ... struts,
6 ... Hanging rope
7 ... Suspended longitudinal cable, 7a ... End (slack part),
8 ...
9 ... Anchor bolt,
10 ... Anchor hardware,
11 ... Turnbuckle,
20, 40 ... buffer part,
21 ... Support bracket (lot),
22 ... Round thimble,
26 ... grips,
27, 41 ... stopper,
31 ... Base steel plate,
32 ... the foundation,
37 ... Yokoun, 37a ... End (slack part),
38 ... longitudinal,
42: Fixing bracket.

Claims (2)

A net for catching falling rocks, and a rope that is directly or indirectly fixed to the ground and supports the net to be deployed,
A plurality of struts that connect and support the rope together with the net, and are fixed directly or indirectly to the ground,
A buffer part attached to at least one of the columns, and when the net receives rock fall, is displaced together with the net to absorb impact energy due to the rock fall, and a buffer part that relaxes the impact force propagating to the net;
Comprising
The buffer portion is
A grip for wrapping and holding at least one of the cords slidably,
A stopper for fixing the end of the grip so as not to move to the support;
A slack portion having a slack in the vicinity of at least one end of the cord between the stopper and the grip;
A semi-constraint member for gently restraining the slack portion to the support;
A net-like structure for preventing falling rocks. 2. The rock fall prevention net-like structure according to claim 1, wherein the buffer portion is provided on a pair of left and right vertical cords that suspend and support the net upward.

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