JP5340871B2 - Falling rock detection fence - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rockfall detecting fence high in detecting sensitivity in a simple structure. <P>SOLUTION: The rockfall detecting fence includes a plurality of posts erected at spaces, and a net body 12 arranged over these posts. A detection cable connected to a displacement detector is provided over the plurality of posts. The post lower in a flexural rigidity than the posts high in the flexural rigidity is disposed between the posts high in the flexural rigidity. Stranded wires for supporting the net body arranged over the respective posts are fixed to the post low in the flexural rigidity, and the stranded wires for supporting the net body are engaged with the posts high in the flexural rigidity, slidably in the longitudinal direction of the stranded wires for supporting the net body. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a rockfall detection fence installed along a track such as a mountainous area or a road.

It is known to install a rockfall detection fence in which a rockfall detection function is added to a rockfall protection fence on the side of a railway or a road installed in a mountainous area.
When a falling rock is detected by the falling rock detection fence, for example, the operation of a train or the like in the section is temporarily postponed or the traveling of the train or the like is stopped to remove the falling rock or the like.

  As the falling rock detection fence, for example, as shown in FIG. 17 and FIG. 15A in which a net is omitted, a detection cable 46 such as a wire or a cable is arranged over each support 45 and at each support 45. As shown in the plan view when the detection fence 47 (and the foundation supporting it) is deformed in FIG. 15 (a) when there is a falling rock, The detection cable 46 such as a detection wire or cable installed over the cable is greatly bent to cause a change in the length of the cable in the longitudinal direction of the fence, and is extended into the displacement detector installed on the end column. In addition, when the length of the detection cable 46 exceeds a predetermined surplus length, the detection cable 46 detects the change with a detector.

  However, in the method of installing the detection cable 46 as described above, the structure is such that the detection cable 46 is fixed over the same column 45 having a large number of bending stiffnesses spaced apart from each other. Even if it bends, since the change in the length of the detection cable 46 is small, it is absorbed by the extra length, and there is a problem that the detection sensitivity (detection accuracy) is low.

  As a detection fence for improving the detection sensitivity, as shown in FIGS. 15B and 16, a pressure receiving plate 49 is embedded and fixed to the ground 2 on the downstream side of the foundation 48 of one of the adjacent columns 45, When the detection fence 51 receives a falling rock, by alternately forming the foundation 48 with the pressure receiving plate and the foundation 50 without the pressure receiving plate so that the horizontal proof stress of the foundations of the adjacent struts are alternately increased or decreased, By making the displacement of the support column 45 of the foundation 50 portion with a small horizontal strength larger than the displacement of the support column 45 of the foundation portion with a large horizontal strength, the change in the length of the detection cable 46 is increased, and the detection sensitivity is higher than in the above case. There is known a detection fence 51 in a form in which the height is increased (see, for example, Patent Document 1).

JP 2009-13656 A

In the conventional case of FIG. 15B, in the detection fence in which the pressure receiving plate 49 is embedded in the ground and fixed downstream of the foundation 48 of one of the adjacent columns 45, the horizontal of the foundation 48 on which the pressure receiving plate 49 is installed. Since it is difficult to accurately control the strength and the horizontal strength of the foundation 50 on which the pressure receiving plate 49 is not installed, the construction is not easy and is affected by the ground around the pressure receiving plate 49. However, there is a problem that it cannot be raised accurately.
An object of the present invention is to provide a falling rock detection fence with a simple structure and high detection sensitivity that advantageously solves the above-described problems.

In order to solve the above-mentioned problem advantageously, the falling rock detection fence according to the first aspect of the present invention comprises a plurality of support columns standing at intervals and a wire mesh arranged across these support columns, and a displacement detector. In the falling rock detection fence in which the detection cable connected to the plurality of columns is provided, a column having a lower bending rigidity than the column having a higher bending rigidity is disposed between the columns having a higher bending rigidity. The mesh-supporting strands arranged in a fixed manner are fixed to the columns having low bending rigidity, and the mesh-supporting strands slide in the longitudinal direction of the mesh-supporting strands with respect to the columns having high bending rigidity. It is characterized by being movably engaged.
In the second invention, in the falling rock detection fence according to the first invention, the foundation of the support column having low bending rigidity is equal to or less than that of the support foundation having high bending rigidity. It is characterized by.
In the third invention, in the falling rock detection fence of the first invention or the second invention, the mesh body is either a mesh body made of a wire mesh with a crimp wire rod meshed or a mesh body made of a wire mesh with a mesh wire made of a spiral wire rod. It is characterized by being.
In the fourth invention, in the falling rock detection fence according to any one of the first invention to the third invention, the net body is fixed to three or more struts, and is firmly fixed to a strut having low bending rigidity. It is characterized by being loosely attached to the high column.
According to a fifth aspect of the present invention, the rockfall detection fence according to any one of the first to fourth aspects includes a displacement detector to which an end of the detection cable is connected.

According to the present invention, the following effects can be obtained.
According to the first aspect of the present invention, a plurality of support columns erected at intervals and a wire mesh arranged over these support columns are provided, and a detection cable connected to the displacement detector is provided over the plurality of support columns. In the falling rock detection fence, struts having lower bending rigidity than struts having high bending rigidity are arranged between struts having high bending rigidity. Since the mesh support strand is fixed to a low-strength strut and is slidably engaged with the strut having a high bending rigidity in the longitudinal direction of the mesh support strand, the strut having a low bending rigidity is provided. When a falling rock is received in the area of the mesh body, the mesh body supporting strand is slid with respect to the support column with high bending rigidity. Is allowed without greatly restraining Compared with a column with high bending rigidity, a column with low bending rigidity is greatly deformed downstream, and the detection cable fixed to the column with low bending rigidity is also greatly deformed. Therefore, it is possible to increase the amount of deformation to the downstream side of the region, and thus it is possible to increase the detection sensitivity of falling rocks.
Further, in the case of the present invention, a structure having a simple structure is obtained because a structure having a large bending rigidity and a structure having a significantly smaller bending rigidity are combined and a net body and a twisted wire for supporting the net body are provided on these. In addition, since mechanical design can be performed, effects such as easy design of a rockfall detection fence controlled to the expected rockfall detection sensitivity can be obtained.
According to the second aspect of the present invention, the support base having a low bending rigidity is equal to or less than that of the support base having a high bending rigidity. Since the foundation can be at least equal to or less than the foundation of a column with high bending rigidity, the construction of the foundation can be made simple and easy, and it can be used as a rockfall detection fence with an inexpensive foundation structure. Is obtained.
In addition, by lowering the support force of the foundation of the column with low bending rigidity compared to the foundation of the column with high bending rigidity, the horizontal strength of the foundation is increased and reduced, and if a rock falls, the falling rock of the column with low bending rigidity is received. The deformation to the downstream side can be further increased.
According to the third invention, the mesh body is either a mesh body made of a wire mesh with a crimp wire rod meshed or a mesh body made of a wire mesh with a mesh wire made of a spiral wire, so that the mesh body is transformed into a parallelogram. Thus, it is possible to obtain an effect such as a falling rock detection fence that can easily cope with the vertical gradient of the slope. In addition, even if snow is generated in the net and a settling force due to the snow acts, the net can be held by the net itself.
According to the fourth invention, the mesh body is fixed to three or more struts and firmly fixed to a strut having low bending rigidity, and is loosely attached to a strut having high bending rigidity. When a rock fall is received in the area near the small strut, the strut part with a large bending rigidity is moved to the strut side with a small bending rigidity, and the part of the net body that receives the rock fall is deformed downstream. The effect that it can make it easy, etc. is acquired.
According to the fifth aspect of the invention, since the displacement detector to which the end of the detection cable is connected is provided, an effect is obtained such that the displacement detector can be operated by the falling rock detection cable and the falling rock can be easily detected. It is done.

It is a partially vertical front view which shows the intermediate part of the rockfall detection fence of this invention. It is a front view which expands and shows the upper part vicinity of a support | pillar with low bending rigidity in FIG. (A) is a top view which expands and shows the support | pillar vicinity with low bending rigidity in FIG. 2, (b) is a vertical side view of (a). (A) is a top view which shows the part which has fixed the net | network body which consists of metal nets with respect to the support | pillar with low bending rigidity, (b) is the front view. It is a front view which expands and shows the upper part vicinity of a support | pillar with high bending rigidity in FIG. (A) is a top view which expands and shows the support | pillar vicinity with high bending rigidity in FIG. 5, (b) is a vertical side view of (a). The relationship between the twisted wire for supporting the upper mesh body, the wire mesh, and the metal fitting is shown, wherein (a) is a front view and (b) and (c) are cross-sectional views. (A) is the front view which expands and shows the coupling coil vicinity of the falling rock detection fence lower part shown in FIG. 1, (b) is a front view of a coupling coil, (c) is a side view of a coupling coil. It is a schematic plan view which shows the planar form of the support | pillar with high bending rigidity, and the support | pillar with lower bending rigidity than that, and the planar form of those foundations. (A) And (b) is a top view which shows the relationship between the net | network body which consists of metal nets, the strand for mesh | body support, and an edge part support | pillar. It is a schematic front view of the falling rock detection fence of this invention. It is a schematic plan view which shows the arrangement | positioning state of a detection cable. It is a front view which shows one form of the mesh body which consists of a wire mesh used in this invention. It is a partially notched side view which shows the net body shown in FIG. (A) is a schematic plan view showing a deformed form when a falling stone acts on a conventional falling rock detection fence, (b) is a modified form when the falling stone acts on a conventional falling rock detection fence provided with a pressure receiving plate on the foundation. It is a schematic plan view shown. It is a top view which expands and shows the relationship between the foundation and pressure receiving plate in FIG.15 (b). (A) And (b) is a vertical side view of a conventional rockfall detection fence, (a) is a diagram in which a support is installed on a foundation without a pressure receiving plate, and (b) shows a form in which the foundation is plastically deformed by rockfall. FIG.

    Next, the present invention will be described in detail based on the illustrated embodiment.

1 to 12 show a rockfall detection fence 1 according to an embodiment of the present invention. In the falling rock detection fence 1 of the present invention, except for the pillars at both ends in the longitudinal direction of the fence, the pillar 3 having a large bending rigidity installed on the independent foundation 5 having a large supporting force, and the independent foundation 5 having a large supporting force. Support columns 6 that are embedded in and fixed to the independent foundation 7 having a remarkably small support force and that have a significantly lower bending rigidity than the support columns 3 that have a higher bending rigidity are arranged at intervals.
In addition, a net body 12 and a net body supporting strand 18 for supporting the net body 12 are fixed to a support column 6 having a small bending rigidity, and a falling rock detection line 13 disposed along the upper part of the net body 12. Is also fixed to the column 6 having a small bending rigidity.
Furthermore, with respect to the support column 3 having a large bending rigidity, the horizontal wire 19, the mesh supporting strand 18, and the falling rock detection cable 13 in the mesh body 12 can be slid relative to each other in the longitudinal direction. (Refer to FIG. 6). Hereinafter, the structure of each part of the falling rock detection fence 1 of the present invention will be described.

  As shown in FIGS. 1, 9, and 11, in the middle portion in the longitudinal direction of the falling rock detection fence 1 of the present invention, the bending rigidity is large in the ground 2 in series in the longitudinal direction of the falling rock detection fence 1. An independent foundation 5 having a large planar outer diameter in which the lower part of the support 3 is embedded and fixed with concrete 4 or the like, and a lower surface of the support 6 having a lower bending rigidity than the support 3 having a higher bending rigidity is embedded and fixed in the concrete 4 A small independent foundation 7 is provided. At both ends in the longitudinal direction of the falling rock detection fence 1, support columns 3 with large bending rigidity are arranged, and support columns 11 for installing the displacement detector 10 are provided outside the support columns 3 at the end portions. (See FIG. 11).

  An independent foundation 5 having a large planar outer diameter and a large supporting force and an independent foundation 7 having a smaller planar outer diameter and a small supporting force are constructed at intervals in the longitudinal direction of the falling rock detection fence 1.

In the independent base 5 having a large planar outer diameter and a large supporting force, a lower part of a column 3 having a large bending rigidity made of a steel square pipe is disposed in a corrugated pipe 8 made of steel or the like embedded and fixed in the ground 2. It is embedded and fixed by concrete 4.
Also, the independent base 7 having a small planar outer diameter and a small supporting force is provided with a column 6 having a small bending rigidity made of a steel member having a hat-shaped cross section in a small diameter pipe 9 made of steel or the like embedded and fixed in the ground 2. The lower part is arranged and fixed by embedding with concrete 4.

  As the column 3 having high bending rigidity, columns having an H-shaped cross section, an I-shaped cross section, a circular or groove-shaped cross section, or a hat-shaped cross section may be used in addition to the rectangular cross section. Further, as a cross-sectional form of the column 6 having a low bending rigidity compared to the column 3 having a high bending rigidity, a column having an H-shaped cross section, an I-shaped cross section, a rectangular cross section, a circular cross section, a groove-shaped cross section, or the like is used. May be. For example, steel materials such as a square steel pipe, a round steel pipe, a grooved steel, a hat-shaped steel, and an H-shaped steel may be used.

Each of the support columns 3 and 6 may be a support column that can absorb an impact and does not break. For example, a metal support such as a steel or aluminum alloy that can be plastically deformed and is not desirable is a support that does not absorb an impact such as concrete and breaks brittlely.
The rigidity ratio between the support column 3 having a high bending rigidity and the support column 6 having a low bending rigidity is set by design. In the present invention, since it is the rockfall detection fence 1, when the net body 12 or the like receives a rockfall, the column 6 having a small bending rigidity is reliably bent and deformed downstream, and the bending rigidity is bent and deformed downstream. The displacement detector 10 is set so as to operate reliably by driving the detection cable 13 arranged and fixed over the small support column 6.

The struts 3 (assumed as A) having a large bending stiffness and the struts 6 (assumed as B) having a smaller bending stiffness may be constructed alternately with ABAB, and an array of AABAABAA is arranged. It may be constructed so as to be configured, or may be formed so as to construct a sequence of BBABBABBA, AABBAABB, or the like.
In accordance with the constructed independent foundation 5 having a large supporting force, a support column 3 having a large bending rigidity is provided, and the independent foundation 7 having a supporting force equal to or smaller than the supporting force of the independent foundation 5 is provided. Is provided with a column 6 having a small bending rigidity.
The support force of the foundation of the support column 6 having a low bending rigidity may be equal to or less than the support force of the foundation of the support column 3 having a high bending rigidity.
In addition, the foundation of the pillar 3 having a large bending rigidity and the foundation of the pillar having a smaller bending rigidity are independent foundations so that the pillar having a small bending rigidity is easily deformed as shown in the figure, rather than a continuous foundation. Is good.

Next, in the present invention, an example of an arrangement form of the mesh body 12 fixed to the column 6 having a lower bending rigidity than the column 3 having a higher bending rigidity will be described with reference to FIG. In addition, the support | pillar 6 with small bending rigidity is made of steel, is provided with the web which inclined so that it may spread on the both sides of the connection flange of a center part, and the edge part flange connected to the web is used as the said connection flange. It is the support | pillar 6 of the cross-sectional hat shape provided in parallel.
As shown in FIG. 13, the net body 12 made of a wire mesh (fence body) is disposed across a support column 3 having a high bending rigidity and a support column 6 having a low bending rigidity, and at least three or more support columns. It is arranged over. The ends of the nets 12 adjacent to each other in the left and right direction in the column 6 portion having a small bending rigidity are overlapped by the portion of the column 6 having a small bending stiffness, and a plurality of mounting brackets 14 spaced in the vertical direction are used. It is fixed to a column 6 having a small bending rigidity (see FIG. 4).
The mesh body 12 includes a crimped wire mesh meshed with a crimp wire or a wire mesh meshed with a spiral wire material, a wire rope mesh body meshed with a wire rope, a wire or a synthetic resin belt or a core material. It is also possible to use a net body made of a synthetic resin band, a net body made of a string or the like, and the like. Details of an example of the net body 12 will be described later.

  Next, with reference to FIG. 2 and FIG. 4, the mounting bracket 14 </ b> A for attaching the left and right end portions of the mesh body 12 made of a crimp wire mesh to the support column 6 with low bending rigidity will be described. 6 is provided with a web made of steel and inclined so as to expand to both sides of the connection flange at the center portion on the upstream side (falling rock side) of the steel 6, and an end flange connected to the web is connected to the connection flange. A support hat 14 having a hat-shaped cross section provided in parallel is fitted and arranged so as to overlap with the support 6 at intervals in the vertical direction of the support 6 having a small bending rigidity, and the left and right crimp wire meshes are attached to the support 14. A plurality of vertical wires 15 at the end of the mesh body 12 are overlapped with each other, and a holding metal fitting 16 is arranged on the bolt and nut 17 so that the support metal fitting 14 and the holding metal fitting 16 approach each other. Ri is tightened, the mesh member 12 is fixed to a small column 6 flexural rigidity. The holding metal fitting 16 is provided with a protrusion 21 that engages with the vertical wire 15. Providing the projections 21 in this way prevents the net body 12 from being detached from the support when receiving rock fall energy, and prevents the vertical wire 15 from slipping out of the horizontal wire 19.

Next, with reference to FIG. 11, an arrangement form of the mesh body supporting strands 18 that support the respective net bodies 12 in the left-right direction will be described. In the illustrated embodiment, the mesh body supporting twist made of steel or the like is illustrated. The wire 18 is provided with an upper mesh body supporting strand 18 so as to extend in the left-right direction along a pair of horizontal wires 19 in the upper part of the rockfall detection fence 1, and a lower pair of horizontal wires 18. Lower mesh body supporting strands 18 are installed so as to extend in the left-right direction along the wire 19, and two mesh body supporting strands 18 are installed one above and below the net body 12 in total. ing.
As shown in FIG. 10, both ends of each of the mesh body supporting strands 18 are screwed and fixed to columns 3 having high bending rigidity located at both ends in the left-right direction of the falling rock detection fence 1. Are connected and fixed. An intermediate portion of each mesh body supporting strand 18 is loosely engaged with the column 3 having high bending rigidity so as to be slidable in the longitudinal direction of the mesh body supporting strand 18. Note that the end of the mesh body 12 is bent with respect to the support column 3 having a large bending rigidity at the end, and the end portion of the mesh body 12 is sandwiched between the end pressing metal fitting 42 and the support column 3 having a large bending rigidity. At the same time, it is fastened and fixed by crimping with bolts 43 and nuts. The bolts 43 are disposed between the vertical wires 15.

The state of the intermediate portion of the upper (or lower) mesh supporting strand 18 will be further described. As shown in FIG. 1, FIG. 5, FIG. 5, or FIG. 12 is bent to provide an upper annular portion 20 at the upper end, and the upper mesh body supporting strands 18 are inserted through the upper annular portions 20 of the mesh body 12. Then, when the net body 12 is deformed by receiving a rock fall load due to falling rocks, a tensile stress can be transmitted from the upper end portion of the vertical wire 15 of the net body 12 to the upper mesh body supporting strand 18, and the net body support. The tension is applied to the stranded wire 18 for use. The upper annular portion 20 may be formed by bending while arranging the mesh body supporting strand 18.
Further, a tension is applied to the upper mesh body supporting strand 18 from the horizontal wire 19 in the mesh body 12 through the vertical wire 15.

Next, with reference to FIG. 6, the relationship between the upper (or lower) mesh support strand 18 and the column 3 having high bending rigidity will be described. The pair of horizontal wires 19 are fitted in the grooves 24 of the hook portion 23 of the hook bolt 22 in a loosely fitted state, and the base end portion of the hook bolt 22 penetrates the front plate of the column 3 having high bending rigidity. It is arranged to penetrate from the hole to the through hole of the back plate, and is fixed to the outside of the back plate by a nut 25 arranged.
The front end portion of the hook bolt 22 is inserted into the through hole 26 of the front plate in the support column 3 having a large bending rigidity and is located inside the support column, and functions to prevent the mesh supporting strand 18 and the horizontal wire 19 from coming off. ing. Since the mesh body supporting strand 18 and the horizontal wire 19 in the mesh body 12 are loosely engaged or loosely engaged with the groove 24 of the hook portion 23 as described above, the mesh body supporting strand is provided. 18 and the horizontal wire 19 of the mesh body 12 are slidable in the longitudinal direction of the twisted wire 18 for mesh body support.
Further, in the illustrated form, since the gap 27 is provided on the downstream side of the rock fall of the groove 24 of the hook portion 23, the mesh body supporting strand 18 and the pair of horizontal wires 19 are moved to the downstream side of the rock fall. After engaging the bottom of the hook groove, a bending force acts on the support column 3 having a high bending rigidity via the hook bolt 22.

Further, as shown in FIG. 3, the upper mesh body supporting strand 18 is made of steel and disposed on the downstream side of the falling rock from the net body 12 over the end flange of the support column 6 having a small bending rigidity. Arranged together with a set of two horizontal wires 19 in the mesh body 12 so as to abut on the support plate 28 and disposed in the groove of the U bolt 29, both legs 30 of the U bolt 29 are connected to the support plate 28 and The mesh body supporting strand 18 is inserted into the web insertion hole of the column 6 having a hat-shaped cross section and having a small bending rigidity, and is tightened by the nut 31. Along with 19, it is fixed to a column 6 having a small bending rigidity.
Further, the attachment relationship between the intermediate portion in the vertical direction of the mesh body 12 and the support column 6 having a small bending rigidity will be described with reference to FIG. 3. The twisted wire 18 for supporting the mesh body is eliminated and the nut 31 is further tightened. Then, the horizontal wire 19 in the mesh body 12 is pressure-bonded to the support plate 28 by the U bolt 31 and fixed to the support column 6 having a small bending rigidity.

  Therefore, when the net body 12 or the like receives a rock fall, stress or the like can be transmitted to the support column 6 having a low bending rigidity via the net body 12 or the net body supporting strand 18. Moreover, since the horizontal wire material in the mesh body 12 and the strands 18 for supporting the mesh body are not fixed to the support column 3 having high bending rigidity, the mesh body 12 and the rock body 12 can be moved against one falling rock. It can be transmitted to the plurality of struts 6 having a small bending rigidity by the mesh body supporting strands 18. In addition, the structure is such that the tension acting on the mesh-supporting stranded wire 18 is first received by the strut 6 having a low bending rigidity.

Next, with reference to FIGS. 6, 11, and particularly FIG. 12, the arrangement state of the falling rock detection rope 13 will be described. A horizontal hole provided so as to penetrate the top of each side plate of each column 3 having high bending rigidity. 32, the rock fall detection cable 13 is inserted and arranged over the back side of each column 6 having low bending rigidity, and is fixed to the column 6 having low bending rigidity by a fixing bracket 33.
As the fixing bracket 33, a U-bolt or the like can be used. With the falling rock detection cable 13 disposed in the groove of the U-bolt, the U-bolt tip is inserted into the column 6 having a small bending rigidity, What is necessary is just to fix the detection cable 13 to the support | pillar 6 with small bending rigidity from the front side of the support | pillar 6 with small bending rigidity with a volt | bolt and a nut.

  Further, as shown in FIGS. 7A and 7B, an intermediate portion of the upper mesh body supporting strand 18 is formed between the longitudinal wires 15 and the mesh body supporting strand 18 and a plurality of horizontal wires 19. Bolts and nuts 35 that are arranged in the grooves of the U-shaped metal fittings 34 made of a steel plate so as to embrace the bolts and are inserted through the bolt holes on the front end sides of the respective side plates of the U-shaped metal fittings 34 are mounted. The metal fitting 34 is prevented from falling off from the mesh body 12 or the mesh-supporting stranded wire 18, and the connection between the U-shaped metal fitting 34 and the mesh body 12 is ensured.

  When the mesh body 12 or the strut 6 having a small bending rigidity receives a falling rock, the strut 6 for supporting a mesh body is fixed to the strut 6 having a small bending rigidity. Compared to the column 3 having a large bending rigidity, the column 3 is greatly deformed. At this time, since the upper mesh body supporting strand 18 is not firmly fixed to the support column 3 having a large bending rigidity, the net body supporting strand 18 is attracted to the portion of the net body 12 that has received a falling rock. Accordingly, the deformation of the support column 6 having a small bending rigidity is increased without restricting the deformation of the support column 6 having a low bending rigidity. Along with this, like the mesh supporting strand 18, the detection cable 13 fixed to the column 6 having low bending rigidity is attracted to the mesh 12 side of the portion that has fallen rocks and protrudes downstream. In the displacement detector 10 connected to this, the both ends of the falling rock detection line 13 are drawn, and when pulled more than a preset extra length, the falling rock detection line 13 or the The limit switch is actuated by the actuated member, and the displacement detector 10 is turned on.

  Further, as described above, the intermediate portion of the upper mesh body supporting strand 18 is fitted with the bolts and nuts 35 that are inserted and disposed over the tip of the U-shaped bracket 34, so When acting on the mesh body 12, tension can be transmitted from the horizontal wire 19 to the mesh body supporting strand 18 via the U-shaped fitting 34, and the bending rigidity of the mesh body supporting strand 18 is small. A bending force is applied to the column 6. Similarly, a bending force is applied to the column 6 having low bending rigidity from the vertical wire 15 via the mesh body supporting strand 18.

  In addition, a lower mesh body supporting strand 18 is disposed on the lower portion of the mesh body 12 across a pair of lower horizontal wires 19, and the lower mesh body supporting strand 18 is paired with a pair of lateral wires. As shown in FIG. 8, the wire rod 19 is bundled by attaching a plurality of short helical coupling coils 36 made of steel or the like attached at intervals so as to embrace the vertical wire rod 15. The tension or the like is transmitted from the wire rod 19 or the vertical wire rod 15 to the lower mesh supporting strand 18 via the coupling coil 36, and stress is applied from the lower mesh supporting strand 18 to the column 6 having low bending rigidity. It is supposed to be transmitted.

  The helical coupling coil 36 is arranged in the gap between the pitches on the open end side of the spiral coil 36 whose one end is opened after the lower mesh support twisting wire 18 is arranged. By feeding the coupling coil 36 so as to dispose the twisted wire 18 for the use, and when there is the vertical wire 15, by feeding the spiral coupling coil 36 so as to embrace the vertical wire 15, Can be installed.

Thus, by setting the coupling coil 36 to the mesh body supporting strand 18, the coupling coil 36 is disposed within the inner diameter of the coupling coil 36, and is used for supporting the horizontal wire 19 of the mesh body 12 and the mesh body via the coupling coil 36. Integration with the stranded wire 18 or combined integration including the vertical wire 15 can be achieved.
The arrangement interval of the coupling coil 36 is appropriately set by design in consideration of the coupling strength with the upper mesh body supporting strand 18 side. The coupling coil 36 may be one continuous between the columns, but a plurality of the coupling coils 36 may be provided at intervals between the columns as shown.

A locking hook portion 38 having a locking groove 37 is formed at the lower end portion of the vertical wire 15 in the mesh body 12 and receives a pulling force so that the mesh body 12 receives a falling rock and the lower portion is lifted upward. When the hook portion 38 is hooked on the lower mesh body supporting strand 18 and is locked, the stress is transmitted to the mesh body supporting strand 18 through the vertical wire 15. It is comprised so that. The hooking hook portion 38 may be U-shaped or J-shaped.
In the illustrated form, the hook portion 38 for locking provided with the locking groove 37 is a mesh body 12 made of a wire mesh embedded and fixed in the ground 2, so that snow accumulated on the mesh body 12 is solidified. The vertical load can be transmitted from the wire mesh to the ground.

  With the configuration as described above, in the falling rock detection fence 1 of the present invention, in particular, the energy of the falling rock is received in the region of the supporting column 6 with low bending rigidity, and the supporting column 6 with low bending rigidity is surely greatly deformed. By increasing the displacement, and by supporting the column 6 with a large bending stiffness after deformation of the column 6 with a small bending stiffness, the detection sensitivity is increased by falling rocks, and by setting the size of the member rigidity The rockfall detection fence is easy to design, has a simple structure, and is easy to construct. When a large falling rock is received, the brace 6 having a small bending rigidity is inclined and deformed, so that the mesh body supporting strand 18 moves to the gap 27 side, and the bending rigidity is large via the U bolt 29. The support column 3 also exerts a support function, and when the falling rock load is large, it is displaced to the falling rock downstream side.

Next, with reference to FIG. 13 and FIG. 14, one form of the net body 12 used in the falling rock detection fence of the present invention will be described. In the falling rock detection fence of the present invention, it is desirable to be able to cope with an inclined land such as a road longitudinal gradient, and therefore, a net body 12 made of a crimp wire mesh using a crimp wire or a wire mesh using a spiral wire material is desirable. In the illustrated embodiment, the fence body 1 uses a crimped wire rod as a vertical wire rod (vertical wire) 19 and a horizontal wire rod (horizontal wire) 15, and a mesh body 12 made of a crimp wire mesh that can be deformed into a parallelogram, It is a net that can handle gradients.
A net 12 made of a wire mesh using crimped wires is formed by knitting a plurality of vertical lines 19 and horizontal lines 15 in a lattice pattern.
Each wire rod of the vertical line 19 and the horizontal wire 15 is a wave-like wire rod having alternating concave portions 40 and convex portions 41, and a wire mesh formed by arranging the vertical lines 19 and the horizontal wires 15 formed by the wire rods in a certain degree. It is configured as. In FIG. 13, a pair of vertical lines 19 at both ends constitutes both sides of the net body, and a pair of horizontal lines 15 at the top and a pair of horizontal lines 15 at the bottom. A plurality of vertical lines 19 and a set of two horizontal lines are arranged inside a rectangular frame which constitutes the upper and lower parts of the net body and is surrounded by the vertical lines 2 on both sides and the uppermost and lowermost horizontal lines 3. 15 is configured as a wire mesh that is knitted by arranging them in a certain degree.
More specifically, at the upper and lower portions and at each side edge, the vertical line 19 and the horizontal line 15 are each formed as a pair, and each vertical line 19 and each horizontal line 15 are braided with a half-pitch shift, The horizontal line 15 is braided with a half-pitch shift with respect to the wave pitch of each vertical line 19, and the vertical line 19 is held from the front and back by the uneven portions of the wave of each horizontal line 15 that is meshed as a set of two or more. Similarly, the horizontal lines 15 are braided so as to embrace the horizontal lines 15 from the front and back by the corrugated portions of the waves of the vertical lines 19 that are meshed as a set of two or more horizontal lines 15.
Further, in the middle portion in the vertical direction, two or more horizontal lines 15 spaced in the vertical direction form a set, and each horizontal line 15 is braided with a half-pitch shift with respect to the wave pitch of the vertical lines 19. Braids are braided so as to embrace the vertical lines from the front and back by the corrugated portions of the waves of the horizontal lines 15 that are braided as a set. In the above-described net body 12, when falling rocks are received, a part of rock falling energy can be absorbed by twisting deformation (elasticity and plasticity) by the tension of the horizontal wire. Further, the vertical wire (or horizontal wire) of the mesh body 12 can transmit tension to the horizontal wire (or vertical wire) at the intersection with the horizontal wire (or vertical wire).

  In addition to the mesh body 12 made of a crimp wire mesh using a crimp wire as described above, a mesh body 12 made of a wire mesh using a spiral wire material as a vertical wire material or a horizontal wire material may be used. Moreover, when installing a detection fence in the flat ground without a vertical gradient, you may make it use a suitable net body.

When practicing the present invention, the coupling coil 36 may be used in place of the U-shaped bracket 34 for coupling the upper mesh body supporting strand 18 with the horizontal wire 19 and the vertical wire 15 at the upper end of the mesh body 12. Good.
In addition, in the falling rock detection fence of the present invention, when the column 6 having a small bending rigidity and the net body 12 of the portion thereof are damaged, the rock falling detection can be performed only by replacing the net body 12 and the column 6 having a small bending rigidity. The fence can be repaired.

DESCRIPTION OF SYMBOLS 1 Falling rock detection fence 2 Ground 3 Column with large bending rigidity 4 Concrete 5 Independent foundation with large planar outer diameter 6 Inclined foundation with small bending rigidity 7 Independent foundation with small planar outer diameter 8 Corrugated pipe 9 Small diameter pipe 10 Displacement detector 11 Column 12 Net Body 13 Detecting cable 14A Mounting bracket 14 Support bracket 15 Vertical wire 16 Holding bracket 17 Bolt / nut 18 Mesh support strand 19 Horizontal wire 20 Upper annular portion 21 Projection 22 Hook bolt 23 Hook portion 24 Groove 25 Nut 26 Through hole 27 Clearance 28 Support plate 29 U bolt 30 Leg 31 Nut 32 Horizontal hole 33 Fixing bracket 34 U-shaped bracket 35 Bolt / nut 36 Coupling coil 37 Locking groove 38 Locking hook 40 Depression 41 Convex 42 End clamp 43 Bolt 45 Post 46 Detection cable 47 Detection fence 48 Foundation 49 Pressure plate 50 Foundation 51 Detection fence

Claims (5)

  In a rockfall detection fence comprising a plurality of struts erected at intervals and a net disposed across these struts, and a detection cable connected to the displacement detector is provided across the plurality of struts, Between the columns with high bending rigidity, columns with lower bending rigidity than the columns with high bending rigidity are arranged, and the strands for supporting the mesh body that are placed across the columns are fixed to the columns with low bending rigidity. The falling rock detection fence is characterized in that the mesh body supporting strand is engaged with a strut having high bending rigidity so as to be slidable in the longitudinal direction of the mesh body supporting strand.   The falling rock detection fence according to claim 1, wherein the foundation of the support column having low bending rigidity has a support force equal to or smaller than that of the support structure having high bending rigidity. .   The falling rock detection fence according to claim 1 or 2, wherein the mesh body is a mesh body made of a wire mesh with a crimp wire rod meshed or a mesh body made of a wire mesh with a spiral wire rod meshed.   The net body is fixed to three or more struts, firmly fixed to a strut having low bending rigidity, and loosely attached to the strut having high bending rigidity. The rock fall detection fence according to any one of the above.   The falling rock detection fence according to any one of claims 1 to 4, further comprising a displacement detector to which an end of the detection cable is connected.

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