JP2010138551A - Rock fall prevention fence - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact rock fall prevention fence which has high rock fall energy absorption efficiency, and is excellent in strength, functionality, construction performance and repairing performance. <P>SOLUTION: Two terminal supports 2 are installed at a predetermined space; a supporting plate 3 is installed in an approximately central position between the terminal supports; a movable intermediate support 4 is placed on the supporting plate in such a manner as to be slidable to a road side; and the right and left terminal supports and the movable intermediate support are connected to each other by means of a plurality of horizontal ropes 5 in such a manner that the movable intermediate support is positioned in the center. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a rockfall protection fence of a type installed along a road or the like to absorb the impact force of rockfall by the elongation of a rope.

As a means to protect roads and houses from falling rocks that occur in the slopes of mountainous areas, several horizontal horizontal ropes are stretched between the columns at intervals, and a wire mesh is attached to the surface of the stretched horizontal rope. A rockfall guard fence is attached to catch rockfalls.
Furthermore, in such a rockfall protection fence, the mooring part of the support and the side rope is connected via a shock absorber, and the sliding friction resistance between the rope and the shock absorber due to the tension when the rock falling from the mountain hits the rope directly There has been proposed one in which impact energy is attenuated and absorbed by plastic deformation of a metal fitting.

However, the collision energy absorption method using the buffer metal fitting plastically deforms the buffer metal fitting, so that the rope terminal and the buffer metal fitting are required to have a strength higher than the breaking load of the rope. When the rope is stretched (the elongation at break is 5% or less), energy absorption cannot be expected so much, and the shock absorber and the rope terminal are directly subjected to impact energy.

Further, in order to increase the amount of absorption of impact energy by the elongation of the rope, it is necessary to increase the distance between the columns, for example, 30 m to 60 m. However, if the span is long, the falling rock occurrence area increases and the amount of falling rocks increases, so it is necessary to increase the rope strength, and it is inevitable to increase the size of the rope end fittings and supports in accordance with the increase in the rope strength. Furthermore, the structure that absorbs impact energy in the entire protective fence increases the difficulty of partial repair, and increases the repair cost.
JP 2002-180422 A

The present invention was devised in order to solve the above-mentioned problems, and the object of the present invention is compact and high in efficiency of absorbing rockfall energy, and excellent in terms of strength, function, construction, and repair. The purpose is to provide a rockfall protection fence.

In order to achieve the above object, the present invention provides two terminal struts at a predetermined interval, and a support plate is installed at a substantially central position between the terminal struts. A support column is placed, and the left and right terminal support columns and the movable intermediate support column are connected by a plurality of horizontal ropes around the movable intermediate support column. (Claim 1)

According to the present invention, the movable intermediate strut is slidably mounted in the road side direction on the support plate installed in the approximate center between the terminal struts at a predetermined interval, and the left and right terminal struts centering on the movable intermediate strut And the movable intermediate strut are connected by a horizontal multistage rope, so the rope is edge-cut at one end strut-movable intermediate strut (1/2 span), and the movable intermediate strut-other end strut (1/2 span) In the case of small or small falling rocks, the impact energy is absorbed by the extension of the rope between the terminal column and the movable intermediate column, and the other terminal columns and the movable intermediate column are not affected. Therefore, the repair work is easy and the cost is low.

In the case of a large or large-scale rock fall, the movable intermediate strut slides on the road side on the support plate due to the impact load applied to the rope, and the total length of the movable intermediate strut on the left and right (one span) is extended (plastic) (Deformation) absorbs impact energy efficiently.
In addition, since it is a guard fence with two terminal struts and one movable intermediate strut in one lot (one span), it is possible to achieve a compact guard fence, facilitating standardization of parts and construction, quality Reliability can be improved. In addition, by repairing the protective fence in units of lots, cost and repair time can be reduced.

Preferably, the support plate is provided with positioning means that allows movement of the movable intermediate strut to the road side due to tension applied to the rope, but does not allow movement to the mountain side.
According to this, the movable intermediate strut can be held at an accurate position in a normal state, and when the falling rock occurs, the displacement of the movable intermediate strut to the road side can be promoted to classify the impact energy.
Preferably, the terminal column and the movable intermediate column are connected by a rope having an elongation P of 20% ≦ P ≦ 65%.
According to this, the energy absorption by the plastic deformation of the rope is large, the rope efficiently absorbs most of the impact energy, and the energy applied to the rope end fitting, terminal strut, movable intermediate strut is attenuated, so these fittings, The member can be downsized.

Preferably, a plurality of upper and lower stages of ropes are coupled with a spacing member, and the upper and lower groups of ropes are integrated.
According to this, even when the falling rock hits one rope directly, the falling rock energy is transmitted to the entire upper and lower ropes by the spacing member, so that the absorption efficiency of falling rock energy is enhanced.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows an embodiment of a rock fall protection fence according to the present invention, where a is a mountain side and b is a road side. Reference numeral 1 denotes a high energy absorption type rock fall protection fence of the present invention installed along the boundary between the road and the mountain side inclined surface.
The rock fall protection fence 1 has terminal struts 2 and 2 erected at intervals on the left and right sides, and a movable intermediate strut 4 which is arranged at a substantially intermediate position between the terminal struts 2 and 2 and is movable in the road side direction. And a plurality of left and right ropes 5 and 5 extending horizontally so that one end is connected to the movable intermediate strut 4 and the other end is connected to the left and right terminal struts 2 and 2, respectively. It is configured as.

The terminal columns 2 and 2 are made of, for example, a steel square column having a size of 450 mm × 450 mm and a length of 4500 mm. The terminal columns 2 and 2 are galvanized in order to enhance the effect of corrosion prevention and scenery, and are further coated with resin. The square column may be a square steel pipe or may be obtained by welding channel steels in an opposing manner.
The terminal columns 2 and 2 are arranged at intervals along the road, and are erected by embedding a lower portion 20 having a required length, for example, 1500 mm, in cement-based foundations 60 and 60 such as mortar and concrete. However, the present invention is not limited to this, and a plate metal fitting with a stay may be provided at the lower portion, and the metal plate may be erected by being rigidly connected to a metal plate (not shown) anchored to a cement-based foundation.

The movable intermediate strut 4 is made of, for example, an H-shaped steel having a size of 200 mm × 200 mm × 8 mm × 12 mm and a height of 3000 mm, and is galvanized to enhance the anticorrosion effect. Furthermore, resin coating may be applied to enhance the landscape.
A foundation 61 made of mortar or concrete is provided on the ground at a substantially intermediate position between the left and right terminal supports 2 and 2 on which the movable intermediate support 4 is to be placed, and the foundation 61 is made of steel plate, resin or concrete. A support plate 3 is provided. The support plate 3 is formed of, for example, 450 mm × 450 mm and a thickness of 7 mm.

In this embodiment, as shown in FIG. 2, four anchor bolts 33 are embedded in the foundation 61 so that the male screw portion of the head protrudes upward. The support plate 3 has through holes 32 corresponding to the anchor bolts 33 at four corners. The support plate 3 is placed on the upper surface of the foundation 61 and has nuts 34 on the heads of the anchor bolts 33 passing through the through holes 32. Are fixed by screwing together. When the support plate 3 is concrete, the support plate 3 can be fixed by being joined to the foundation 61 with mortar, or it can be built on-site using a formwork or the like.

The movable intermediate column 4 is placed on the support plate 3 so that the flange portions 45, 45 face the mountain side and the road side. Positioning means 31 is provided on the surface of the support plate 3 to allow movement of the movable intermediate strut 4 to the road side due to tension applied to the rope 5 but not to allow movement to the mountain side.

In this embodiment, as the positioning means 31, as shown in FIG. 2, protrusions 31A, 31B protrude in a support plate shape on the mountain side and the road side so as to face the flanges 45, 45 of the movable intermediate column 4. The protrusion 31A on the mountain side has a vertical surface on the side facing the flange of the movable intermediate strut 4 so as to function as a barrier. In this example, the cross section is rectangular. On the other hand, the projecting portion 31B on the road side is a sliding allowance portion, and the side facing the flange 45 of the movable intermediate column 4 is inclined, and has a triangular cross section with the tip perpendicular to or close to the top from the top. Thus, the lower end of the movable intermediate strut 4 can get over and move when a certain load or more is applied.

In this example, the protrusions 31A and 31B are in the form of ridges or banks with a length equal to or greater than the flange, but are divided into a plurality of peaks or protrusions as shown in FIG. Also good. These protrusions and protrusions 31A and 31B are formed by joining or welding members or punching a support plate.
In some cases, as shown in FIG. 3 (b), the support plate 3 is composed of two overlapping plates of a lower plate 301 and an upper plate 300, and the lower end of the movable intermediate column 4 serves as a positioning means 31 on the upper plate 300. A rectangular window hole having a size and shape that can be fitted into the window hole is formed, and the side on the mountain side of the window hole is a vertical surface 311A for a barrier, and the side on the road side is a sliding allowance portion and is shallow toward the upper surface, not vertical. The lower end of the movable intermediate strut 4 can get over and move when a certain load or more is applied.

As described above, the movable intermediate column 4 is arranged on the plate 3 so that the flanges 45, 45 face the mountain side and the road side. The movable intermediate column 4 has the terminal columns 2, 2, Are connected by horizontal multi-stage ropes 5 and 5.
The rope 5 is controlled so that the yield ratio of the constituent wire is in the range of 0.5 to 0.7 (yield point / tensile breaking load) and the elongation P is 20% ≦ P ≦ 65%. A big rope is used.
The reason why the lower limit of elongation is set to 20% is that if it is less than this, energy absorption is small and a sufficient effect cannot be obtained, and the upper limit is set to 65% because if the elongation exceeds this, rock falls on the road more than necessary. Because it protrudes. It is desirable to keep the upper limit at 55% so as not to obstruct traffic of large vehicles.
As a specific example of the rope 5, the structure is 3 × 7, the diameter is 18 mm, the material is soft stainless steel, the breaking load is 84 kN, the elongation is 52%, and the absorbed energy is 35 kN · m. The rope 5 is preferably resin-coated in order to enhance the landscape effect.

Next, the structure for extending the rope 5 to the terminal column 2 and the terminal column 4 will be described. First, in order to stretch the rope 5 to each terminal column 2, the side facing the movable intermediate column 4 and the opposite side thereof. In addition, for example, holes 21 and 21 are provided at 10 positions at intervals in the vertical direction. The holes 21 and 21 are in a straight line.
An end portion of the rope 5 for connecting to the terminal column 2 is an eyebolt terminal 56. That is, as shown in FIG. 4A, the rope 5 inserted through the metal tube 512 such as aluminum or stainless steel is buried in the ring of the eyebolt 511 and then turned back and inserted into the metal tube 512 from the opposite side. The metal tube is clamped with.
The eyebolt terminal 56 is inserted into the holes 21 and 21 of the terminal column 2 and is connected and fixed to the terminal column 2 by screwing a nut 58 into a male screw protruding from the hole.

As shown in FIG. 5, a hole 47 through which a connecting pin 52 made of a bolt for connecting the rope 5 is passed through the mountain 45 and the road-side flanges 45, 45 of the movable intermediate column 4 on the left and right sides of the web 46. 47 is provided. The holes 47 and 47 are in a straight line, and the left and right sets are parallel.
The end of the rope 5 connected to the movable intermediate strut 4 is folded back so that the rope 5 inserted through the metal tube 512 has a loop shape, and is inserted again into the metal tube 512 to press the metal tube and toyolock terminal 57 It has become.
In connection, the color pipe 53, the toyo lock terminal 57, and the color pipe 53 are arranged in this order between the road side flange 45 and the mountain side flange 45, and the connection pin 52 is connected from the hole 47 on the road side to the color pipe 53, the toyo lock terminal 57, The collar pipe 53 and the mountain side hole 47 are sequentially inserted and fastened with a nut 59 screwed into the male thread at the end of the connecting pin 52.

And in order to protect the toyo lock terminal 57 attached to the movable intermediate column 4 from the collision of falling rocks, a cover 55 is disposed on the mountain side flange 45 and fixed with the nut 59. The cover 55 is a rectangular iron plate having a thickness of, for example, about 5 mm, processed into an umbrella shape so as to draw an arc larger than the flange. The cover 55 has a horseshoe shape attached to the movable intermediate column 4 inside the arc. A processed spring plate portion 550 is provided, and a through hole through which the connecting pin 52 is inserted is provided at an end of the spring plate portion.
The rope tension of the rope 5 stretched between the terminal column 2 and the movable intermediate column 4 is adjusted by a nut 58 screwed into an eyebolt 511 penetrating the terminal column 2. Since the attachment of the movable intermediate strut 4 to the end strut 2 (1/2 span) with the rope 5 is the same as described above, the description thereof is omitted.

As shown in FIG. 6, the multi-stage ropes 5 and 5 are connected and fixed to the interval holding member 6 by a U-shaped metal fitting 601 and a nut 602 at a substantially central portion of the terminal support 2 and the movable intermediate support 4. The spacing member 6 is, for example, a pipe having a diameter of 90 mm and a thickness of 3.2 mm, and is connected and fixed substantially vertically to the ten-stage rope 5 at a substantially middle point between the terminal column 2 and the movable intermediate column 4. . Further, a rhombus metal mesh 7 of 50 mm × 50 mm is arranged on the road side front surface of the terminal column 2 -the movable intermediate column 4 and is attached to the rope 5 with a coupling coil (not shown).
The spacing member 6 and the wire mesh 7 are galvanized and resin-coated to enhance the anticorrosion and landscape effect.

FIG. 7 shows a schematic diagram of a state where a falling rock collides with the falling rock prevention fence of the present embodiment. When the falling rock G collides with the left half span as shown in FIG. 7A, the left rope 5 extends to the road side as shown in FIG. The tension pulling to the side works. This tension is transmitted to all ropes stretched in the vertical direction of the left 1/2 span by the spacing member 6.
When this tension exceeds a certain value (for example, 50 kN), the lower end portion of the movable intermediate column 4 is allowed to slide (the road side protrusion or protrusion 31B) of the positioning means 31 on the support plate 3 as shown in FIG. Alternatively, the movable intermediate strut 4 moves to the road side by slipping over the inclined surface 311B).

The left and right ropes 5 and 5 ′ were cut off by the movable intermediate strut 4, but when the movable intermediate strut 4 moves to the road side, the tension is transmitted to the right rope 5 ′ and the right half span rope 5 'Also extends, the terminal struts act as a single rope, and the plastic deformation is expanded, so that the efficiency of collision energy absorption is enhanced. In addition, rock fall is guided to the center of G and has the effect of relaxing the collision energy.

The connecting portion of the rope of the movable intermediate column 4 is covered with a cover 55, so that the rope terminal is protected from being destroyed even if the falling rock G collides. Therefore, the rope breakage after falling rocks can be repaired only by replacing the approximately 5 m rope, and the cover 55 can be replaced simultaneously with the replacement of the rope. Further, in repairing damage to the rope 5 due to falling rocks, the rope 5 of the falling rock protection fence 1 (1 span) is edge-cut by the movable intermediate strut 4 in units of 1/2 left and right as described above. When 4 does not move, repair (replacement etc.) of the rope 5 of 1/2 span is sufficient.

A second embodiment is shown in FIG. In this example, a plurality of protective fences (1 span) of about 10 m shown in the first embodiment are continuously arranged according to the installation location. The intermediate movable intermediate strut 4 and the spacing member 6 are not shown.
In this embodiment as well, holes for attaching eyebolt terminals 56, which are rope connection fittings, are provided on the left and right surfaces of the terminal column 2, but the holes are two sets of 21 and 21 'holes on the mountain side and the road side. It is opened in parallel at intervals.
The first span 901 uses the road-side hole 21 ′, and the second span 902 uses the mountain-side hole 21 to share one terminal column 2 for the first span 901 and the second span 902. Can do. The third span 903 and thereafter can be similarly installed.

(A) is a front view which shows 1st Example of the rock fall protection fence by this invention, (b) is a top view. (A) is a front view which shows an example of the positioning means in the support plate of this invention by engagement with a movable intermediate | middle support | pillar, (b) is a top view, (c) is a side view. (A) is a top view which shows the other example of the positioning means in a support plate, (b) is a side view which shows the other example of the positioning means in a support plate. (A) is a front view which shows the connection relation of the rope terminal of this invention, and a terminal support | pillar, (b) is a top view. (A) is a front view which shows the connection part of a movable intermediate | middle support | pillar and a rope, (b) is a cross-sectional view. (A) is a front view which shows the space | interval maintenance material of this invention, (b) is a top view. It is a schematic diagram which shows the behavior of the falling rock colliding with the falling rock protection fence of this invention, and the change of a protection fence. The 2nd Example which connected two or more rockfall protection fences of this invention is shown, (a) is a front view, (b) is a top view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Falling rock guard 2 Terminal support | pillar 3 Support plate 4 Movable intermediate support | pillar 5 Rope 6 Space | interval holding material 31 Positioning means

Claims (4)

Two terminal struts are provided at a predetermined interval, a support plate is installed at a substantially central position between the terminal struts, a movable intermediate strut slidable on the road side is placed on the support plate, and the movable intermediate strut A rockfall protection fence characterized by connecting the left and right terminal struts and movable intermediate struts with a multi-level horizontal rope.   The rock fall protection provided according to claim 1, wherein the support plate is provided with positioning means for allowing movement of the movable intermediate strut to the road side by tension applied to the rope but not allowing movement to the mountain side. fence. The rock fall protection fence according to claim 1 or 2, wherein the rope has an elongation P of 20% ≦ P ≦ 65%. The rock fall protection fence according to any one of claims 1 to 3, wherein a plurality of upper and lower steps of rope are joined together by a spacing member.

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