JP7546183B2 - Intermediate posts for rockfall prevention fences and rockfall prevention fences - Google Patents

Description

The present invention relates to intermediate supports for rockfall prevention fences and rockfall prevention fences.

Rockfall prevention fences have been known for some time and are installed on slopes in mountainous areas or on roadsides adjacent to slopes to catch rocks falling from the mountain side. Patent Document 1 below discloses a protective fence as an example of such a rockfall prevention fence.

The protective fence disclosed in Patent Document 1 is installed over a specified range on the slope of a mountainside. This protective fence has a pair of terminal pipe supports erected at a distance from each other, an intermediate pipe support erected between the pair of terminal pipe supports at a distance from the terminal pipe supports, multiple rope materials stretched across the pair of terminal pipe supports and the intermediate pipe support and arranged at specified intervals above and below, and a wire mesh that covers the area between the pair of terminal pipe supports and is arranged on the mountain slope side of the intermediate pipe support and the multiple rope materials and fixed to the multiple rope materials.

The intermediate pipe support has a steel pipe erected on a slope and an engagement part attached to the outer surface of the steel pipe and engaging with the middle part of the rope material. The engagement part has a pair of engagement members welded to the outer surface of the steel pipe and protruding from the outer surface, and the pair of engagement members are arranged at a distance from each other vertically, and an insertion receiving part is formed between the pair of engagement members into which the rope material is inserted to receive the rope material. Each of the pair of engagement members is made of a round bar with a circular cross section, and the tip of the upper engagement member in the protruding direction of the pair of engagement members has a notched step part at its upper part, and the tip of the lower engagement member in the protruding direction has a notched step part at its lower part. In addition, the tip of the upper engagement member and the tip of the lower engagement member are provided with a through hole that penetrates the tip at the position of each notched step part.

A bolt is then inserted through the through hole of the upper engaging member and the through hole of the lower engaging member, and a nut is screwed onto the bolt, so that the bolt is installed between the tip of the upper engaging member and the tip of the lower engaging member, and the opening between the tip of the upper engaging member and the tip of the lower engaging member is closed by the bolt. This allows the rope member to be held in the insertion receiving portion between the upper engaging member and the lower engaging member.

Patent No. 4613864

When a rockfall prevention fence is hit by a falling rock, the wire mesh bends in the direction of the impact of the rockfall, and the portions of the wire mesh located on both sides of the impact point of the falling rock are pulled toward the impact point. In this case, in the configuration disclosed in Patent Document 1, there is a risk that the wire mesh will get caught on the engaging member that forms the insertion receiving portion that receives the middle portion of the rope material in the intermediate pipe support. Specifically, the tip surface and the outer circumferential surface of the engaging member made of a round bar are arranged perpendicular to each other and a corner is formed between them, so when the wire mesh is pulled toward the impact point of the falling rock as described above, it may get caught on the corner of the tip of this engaging member. If such a catch occurs, the wire mesh is restrained at the caught portion, and as a result, the absorption of the impact energy of the falling rock is hindered.

When a rock hits the rockfall prevention fence, not only the wire mesh but also the rope material is pulled towards the point of impact of the rock. If the rock hits the fence diagonally upwards, the rope material is displaced upwards and rubs strongly against the upper engaging member of the intermediate pipe support, and if the rock hits the fence diagonally downwards, the rope material is displaced downwards and rubs strongly against the lower engaging member of the intermediate pipe support. If the point where the rope material rubs is such that it gets caught, the rope material is restrained at that point, and as a result, it is prevented from absorbing the impact energy of the falling rock.

The object of the present invention is to provide an intermediate support for a rockfall prevention fence and a rockfall prevention fence that can prevent the cable and wire mesh corresponding to the rope material from getting caught on a member that defines a receiving space that receives the middle part of the cable when a falling rock hits the rockfall prevention fence, thereby preventing the absorption of the impact energy of the falling rock from being hindered.

The present invention provides an intermediate support for a rockfall prevention fence, which includes a cable stretched between a pair of spaced apart side supports and a wire mesh fixed to the cable in a manner that covers the area between the pair of side supports, and is used in a rockfall prevention fence that receives rocks falling from the mountain side, and is installed between the pair of side supports on the opposite side of the mountain side with respect to the wire mesh in order to support a cable intermediate section, which is the intermediate section between both ends of the cable. The intermediate support for a rockfall prevention fence includes a support body that is erected on the ground, and a first axial movement limiting section and a second axial movement limiting section that are installed on the outer surface of the support body so as to protrude from the outer surface of the support body. The first axial movement limiting section and the second axial movement limiting section protrude from the outer surface of the support body on one side of the receiving space in the axial direction of the support body and the opposite side to the one side, respectively, so as to define a receiving space that receives the cable intermediate section. The first axial movement limiting portion has a first outer end surface facing outward in the protruding direction of the first axial movement limiting portion from the outer surface of the support body, and the first outer end surface has a first outer end surface curved surface portion that is a convex surface curved so as to approach the support body as it moves toward both outer sides in the width direction of the first axial movement limiting portion perpendicular to both the axial direction of the support body and the protruding direction of the first axial movement limiting portion. The second axial movement limiting portion has a second outer end surface facing outward in the protruding direction of the second axial movement limiting portion from the outer surface of the support body, and the second outer end surface has a second outer end surface curved surface portion that is a convex surface curved so as to approach the support body as it moves toward both outer sides in the width direction of the second axial movement limiting portion perpendicular to both the axial direction of the support body and the protruding direction of the second axial movement limiting portion.

The present invention also provides a rockfall prevention fence for receiving rocks falling from the mountain side. The rockfall prevention fence includes a pair of side supports installed at a distance from each other, a cable stretched between the pair of side supports, a wire mesh fixed to the cable while covering the area between the pair of side supports, and a middle support installed between the pair of side supports on the opposite side of the mountain side from the wire mesh to support a cable middle section, which is the middle section between both ends of the cable. The middle support has a support body erected on the ground, and a first axial movement limiting section and a second axial movement limiting section installed on the outer surface of the support body so as to protrude from the outer surface. The first axial movement limiting section and the second axial movement limiting section protrude from the outer surface of the support body on one side and the other side of the receiving space in the axial direction of the support body, respectively, so as to define a receiving space for receiving the cable middle section. The first axial movement limiting portion has a first outer end surface facing outward in the protruding direction of the first axial movement limiting portion from the outer surface of the support body, and the first outer end surface has a first outer end surface curved surface portion that is a convex surface curved so as to approach the support body as it moves toward both outer sides in the width direction of the first axial movement limiting portion perpendicular to both the axial direction of the support body and the protruding direction of the first axial movement limiting portion. The second axial movement limiting portion has a second outer end surface facing outward in the protruding direction of the second axial movement limiting portion from the outer surface of the support body, and the second outer end surface has a second outer end surface curved surface portion that is a convex surface curved so as to approach the support body as it moves toward both outer sides in the width direction of the second axial movement limiting portion perpendicular to both the axial direction of the support body and the protruding direction of the second axial movement limiting portion.

In the configuration of the intermediate support for rockfall prevention fence and rockfall prevention fence according to the present invention described above, the first and second outer end surface curved portions of the first and second outer end surfaces of the first and second axial movement limiting portions are curved convex surfaces, respectively, so that when a falling rock strikes the rockfall prevention fence and the wire mesh and cable are pulled toward the point of impact of the falling rock, the wire mesh and cable can be prevented from getting caught on the first or second axial movement limiting portion, and this can be prevented from impeding the absorption of the impact energy of the falling rock by the rockfall prevention fence.

It is preferable that the intermediate support further includes a separation limiting section that is installed between the first axial movement limiting section and the second axial movement limiting section so as to limit the movement of the cable intermediate section received in the receiving space in the separation direction. The separation direction is perpendicular to the axial direction of the support body and away from the support body.

It is preferable that the first axial movement limiting portion further has a first opposing surface that faces the second axial movement limiting portion across the receiving space, and that the first opposing surface has a first opposing surface curved surface portion that is a convex surface that curves away from the second axial movement limiting portion as it moves toward both outside sides in the width direction of the first axial movement limiting portion.

It is preferable that the second axial movement limiting portion further has a second opposing surface that faces the first axial movement limiting portion across the receiving space, and that the second opposing surface has a second opposing surface curved surface portion that is a convex surface that curves away from the first axial movement limiting portion as it moves toward both outside sides in the width direction of the second axial movement limiting portion.

As described above, the present invention provides an intermediate support for a rockfall prevention fence and a rockfall prevention fence that can prevent the cable and wire mesh from getting caught in the first or second axial movement restriction section when a rock hits the rockfall prevention fence, preventing the absorption of the impact energy of the rock from being hindered.

FIG. 1 is a front view of a rockfall prevention fence according to one embodiment of the present invention, as viewed from the road side (the side opposite the mountain side). 1 is a plan view (top view) of a rockfall prevention fence according to one embodiment of the present invention. FIG. FIG. 2 is a partial view of the vicinity of an intermediate support post of a rockfall prevention fence according to one embodiment of the present invention, the view being taken from the mountain side. 4 is a cross-sectional view of the rockfall prevention fence at the IV-IV position in FIG. 3. This is a partial view of the trapping portion of the intermediate support of the rockfall prevention fence and the cable as viewed from the mountain side. 6 is a top view of the vicinity of the trapping portion of the intermediate support and the cable shown in FIG. 5, viewed along the axial direction of the support body. 6 is a side view of the vicinity of the trapping portion of the intermediate support and the cable shown in FIG. 5 along the extension direction of the cable. FIG. FIG. 13 is a diagram partially illustrating a rockfall prevention fence in a deformed state after being hit by a falling rock. This is a view from above of the trapping portion of the intermediate support of a rockfall prevention fence according to one modified embodiment of the present invention, and the cable, along the axial direction of the support body.

The following describes an embodiment of the present invention with reference to the drawings.

The rockfall prevention fence 1 (see FIG. 1) according to one embodiment of the present invention is designed to receive rocks that fall from the mountain side and prevent them from falling onto the road, and is installed on the side of the road adjacent to the mountain slope in a direction perpendicular to the direction facing the mountain side (hereinafter referred to as the mountain side direction). In other words, the rockfall prevention fence 1 is installed on the side of the road adjacent to the mountain slope along the direction in which the road extends. The direction in which the rockfall prevention fence 1 extends is referred to as the width direction of the rockfall prevention fence 1. As shown in FIG. 1, the main components of the rockfall prevention fence 1 include multiple side supports 2, multiple cables 3, brake elements 4, multiple spacing members 5, one wire mesh 6, multiple fixing members 7, multiple auxiliary supports 8, and an intermediate support 9.

The multiple side supports 2 are erected on the ground G beside the road at intervals in a direction perpendicular to the mountain side direction, i.e., in the width direction of the rockfall prevention fence 1. In other words, the multiple side supports 2 are erected on the ground G beside the road at intervals along the direction in which the road extends. The double-sided supports 2 are disposed on both sides of the cable 3 and support the cable 3 in a taut state. The multiple side supports 2 include a pair of terminal supports 12 and at least one intermediate support 14.

A pair of terminal posts 12 are disposed at both ends of the rockfall prevention fence 1 in the width direction of the rockfall prevention fence 1. In FIG. 1, only a certain range from one end of the rockfall prevention fence 1 in the width direction of the rockfall prevention fence 1 is partially shown, so only one of the pair of terminal posts 12, the terminal post 12 disposed at one end of the rockfall prevention fence 1, is shown.

At least one relay post 14 is disposed between a pair of terminal posts 12. A cable 3 is disposed between each of the pair of terminal posts 12 and the adjacent relay post 14, with one end and the other end of the cable 3 being connected to the corresponding terminal post 12 and relay post 14, respectively. Furthermore, when multiple relay posts 14 are included in multiple side posts 2, that is, when multiple relay posts 14 are disposed between a pair of terminal posts 12, the multiple relay posts 14 are disposed at intervals in the width direction of the rockfall prevention fence 1. Then, a cable 3 is disposed between adjacent ones of the multiple relay posts 14, with one end and the other end of the cable 3 being connected to the corresponding relay post 14, respectively.

As described above, one end and the other end of the cable 3 are connected to the terminal post 12 and the adjacent relay post 14, and the cable 3 is stretched between the terminal post 12 and the relay post 14. In addition, when multiple relay posts 14 are arranged between a pair of terminal posts 12, the cable 3 is also arranged between adjacent ones of the multiple relay posts 14 as described above, and one end and the other end of the cable 3 are connected to the corresponding relay posts 14, so that the cable 3 is stretched between the adjacent relay posts 14. In other words, between a pair of terminal posts 12, multiple cables 3 are connected in the width direction of the rockfall prevention fence 1 via the relay posts 14. Between the adjacent side posts 2 where the cables 3 are stretched, multiple cables 3 are arranged at a predetermined interval in the axial direction (up and down direction) of the side posts 2. Each cable 3 extends in the width direction of the rockfall prevention fence 1. In addition, one end and the other end of each cable 3 are connected to the corresponding side posts 2 via the corresponding brake elements 4.

The brake element 4 absorbs impact energy when an impact acts on the cable 3 connected to the brake element 4. Various known configurations can be used as this brake element 4, but for example, an element including a brake element cable connected to the two side supports 2 and a plate-like member having a through hole through which the brake element cable is inserted and connected to the cable 3, and configured to absorb impact energy by utilizing friction generated between the inner surface of the through hole of the plate-like member and the brake element cable when a falling rock hits the rockfall prevention fence 1 and an impact acts on the cable 3 such that it pulls the cable 3 in a direction away from the brake element 4, or the like, can be used.

The multiple spacing retainers 5 maintain the spacing between adjacent ones of the multiple cables 3 arranged in a line along the axial direction of the side supports 2. The spacing retainers 5 are arranged between the intermediate supports 9 and auxiliary supports 8 arranged as described below between adjacent side supports 2 in the width direction of the rockfall prevention fence 1, and between the auxiliary supports 8 and the side supports 2. Each spacing retainer 5 is a member that extends in the axial direction of the side supports 2, and is connected to each of the multiple cables 3 arranged in a line in that direction, thereby maintaining the spacing between adjacent ones of the multiple cables 3.

The wire mesh 6 is for receiving falling rocks between a pair of terminal supports 12, and is fixed to the multiple cables 3 in a state in which it covers the area between the pair of terminal supports 12, in other words, the area between the adjacent two side supports 2. That is, the wire mesh 6 extends over the range from one terminal support 12 to the other terminal support 12. The wire mesh 6 is disposed on the mountain side of the relay support 14 and each cable 3 between the pair of terminal supports 12 (see Figure 2). Note that in Figure 1, the mesh of the wire mesh 6 is partially shown in order to make it easier to see the cables 3, brake elements 4, and fixing members 7 that overlap with the wire mesh 6.

The wire mesh 6 is fixed to each cable 3 by a number of fixing members 7. Specifically, each fixing member 7 is made of a metal coil wound around the cable 3, and is joined to the wire mesh 6 by threading through the mesh of the wire mesh 6, thereby connecting the cable 3 and the wire mesh 6. The fixing members 7 are respectively arranged between the two side supports 2 and the spacing members 5 adjacent to those two side supports 2, between adjacent spacing members 5, and between the spacing members 5 and the auxiliary support members 8 adjacent to those spacing members 5 as described below, and connect the cable 3 and the wire mesh 6 at the positions where they are arranged.

The auxiliary support material 8 supplementarily supports each cable 3 between each of the two side supports 2 and the adjacent intermediate support 9 as described below. The auxiliary support material 8 is disposed in the center between each of the two side supports 2 and the adjacent intermediate support 9. In this embodiment, the auxiliary support material 8 is made of an angle material, and is erected on the ground G so as to extend parallel to the two side supports 2 and the intermediate support 9. The corresponding portions of each cable 3 are connected to the auxiliary support material 8, and each cable 3 is thereby supported by the auxiliary support material 8.

The intermediate supports 9 are installed between adjacent ones of the multiple side supports 2 in the width direction of the rockfall prevention fence 1 on the side opposite the mountain side to the wire mesh 6 (on the road side of the wire mesh 6 in this embodiment) in order to support the cable intermediate portion 3a (see FIG. 3), which is the intermediate portion between both ends of the cable 3. Specifically, the intermediate supports 9 are installed between each terminal support 12 and the adjacent relay support 14, and when multiple relay supports 14 are installed between a pair of terminal supports 12, the intermediate supports 9 are also installed between adjacent ones of the multiple relay supports 14. In this embodiment, multiple intermediate supports 9 are installed at predetermined intervals between each terminal support 12 and the adjacent relay support 14, and when multiple relay supports 14 are installed between a pair of terminal supports 12, multiple intermediate supports 9 are similarly installed at predetermined intervals between adjacent ones of the multiple relay supports 14. Each terminal post 12, each intermediate post 14, and each intermediate post 9 are installed side by side along the width direction of the rockfall prevention fence 1.

As shown in Figures 3 and 4, each intermediate support 9 has a support body 22 and multiple containment sections 24. Each intermediate support 9 has multiple containment sections 24, the number of which corresponds to the number of cables 3 arranged in a line along the axial direction of the two side supports 2.

The pillar body 22 is columnar (cylindrical in this embodiment) and is erected on the ground G so that its lower portion is buried in the ground and protrudes upward from the ground G. In this embodiment, the pillar body 22 is made of a steel pipe.

Each of the multiple confinement sections 24 defines a receiving space 26 surrounding the cable intermediate section 3a, which is the intermediate section between both ends of the corresponding cable 3, when the cable intermediate section 3a extends in a direction perpendicular to the axial direction of the support body 22 (the width direction of the rockfall prevention fence 1), and when the cable intermediate section 3a is received in the receiving space 26, it confines the cable intermediate section 3a so as to restrict movement of the cable intermediate section 3a in the axial direction of the support body 22 (the extension direction of the support body 22) and movement of the cable intermediate section 3a in the moving away direction, which is perpendicular to the axial direction of the support body 22 and away from the support body 22 towards the mountain side, while allowing movement of the cable intermediate section 3a in the extension direction. The multiple containment sections 24 are each installed on the mountain side surface 22a (hereinafter referred to as the mountain side surface 22a) of the outer surface (peripheral surface) of the portion of the support body 22 that protrudes upward from the ground G, so as to protrude toward the mountain side from the surface 22a. The multiple containment sections 24 are arranged at predetermined intervals along the axial direction of the support body 22.

Each of the multiple containment sections 24 has dimensions that prevent the containment section 24 from entering the mesh of the wire mesh 6 even if the wire mesh 6 is pressed against the containment section 24 from the mountain side. In other words, each containment section 24 has a dimension larger than the size of the mesh of the wire mesh 6 when viewed from the mountain side. Specifically, the dimension W1 of each containment section 24 in the width direction of the rockfall prevention fence 1 is larger than the dimension W11 of the mesh of the wire mesh 6 in the same direction, and the dimension W2 of each containment section 24 in the axial direction of the support body 22 is larger than the dimension W12 of the mesh of the wire mesh 6 in the same direction.

As shown in FIG. 5, each confinement section 24 has a first axial movement limiting section 35, a second axial movement limiting section 36, and a separation limiting section 37.

The first axial movement limiting portion 35 protrudes from the crest side 22a of the support body 22 on one side of the receiving space 26 so as to limit the movement of the cable intermediate portion 3a received in the receiving space 26 to one side of the receiving space 26 in the axial direction of the support body 22. Specifically, the first axial movement limiting portion 35 protrudes from the crest side 22a of the support body 22 on the tip side of the receiving space 26 so as to limit the movement of the cable intermediate portion 3a received in the receiving space 26 to the tip side of the support body 22 in the protruding direction of the support body 22 from the ground G. The first axial movement limiting portion 35 is made of a curved steel plate and is fixed to the crest side 22a of the support body 22 by welding in a position protruding from the crest side 22a of the support body 22 to the crest side. The first axial movement limiting portion 35 has a first outer end surface 41, a pair of first side surfaces 42, a first opposing surface 43, and a first opposing surface 44.

The first outer end surface 41 is an end surface facing outward in the protruding direction of the first axial movement limiting portion 35 from the crest side 22a of the pillar body 22, and is a surface that receives the wire mesh 6 stretched between a pair of terminal pillars 12. In other words, the first outer end surface 41 is an end surface of the first axial movement limiting portion 35 facing the crest side, and contacts the wire mesh 6 arranged on that crest side. The first outer end surface 41 is formed by a first outer end surface curved surface portion 41a (
The first outer end surface curved portion 41 a has an arc shape when viewed from the axial direction of the support body 22 .

In this embodiment, the first outer end surface curved surface portion 41a extends over the entire first outer end surface 41. That is, the first outer end surface 41 is a continuously curved convex surface over the entire width direction of the first axial movement limiting portion 35 from one end to the other end of the first outer end surface 41. The first outer end surface 41 is curved with a constant curvature over the entire width direction of the first axial movement limiting portion 35 from one end to the other end of the first outer end surface 41. That is, the entire first outer end surface 41 forms an arc shape with a constant curvature when viewed from a direction along the axial direction of the support body 22.

The pair of first side surfaces 42 are surfaces of the first axial movement limiting portion 35 facing both outside in the width direction of the first axial movement limiting portion 35. One of the pair of first side surfaces 42 extends continuously from one end of the first outer end face 41 in the width direction of the first axial movement limiting portion 35 along the protruding direction of the first axial movement limiting portion 35 to the crest side surface 22a of the support body 22, and the other first side surface 42 extends continuously from the other end of the first outer end face 41 in the width direction of the first axial movement limiting portion 35 along the protruding direction of the first axial movement limiting portion 35 to the crest side surface 22a of the support body 22.

The first opposing surface 43 (see FIG. 5) is a surface that faces the second axial movement limiting portion 36 across the receiving space 26 in the axial direction of the support body 22. This first opposing surface 43 has a first opposing surface curved surface portion 43a that is a convex surface that curves away from the second axial movement limiting portion 36 as it moves from the center in the width direction of the first axial movement limiting portion 35 to both outside sides. The first opposing surface curved surface portion 43a has an arc shape when viewed from a direction perpendicular to the axial direction of the support body 22 (the protruding direction of the first axial movement limiting portion 35).

In this embodiment, the first opposing surface curved surface portion 43a extends over the entire first opposing surface 43. That is, the first opposing surface 43 is a continuously curved convex surface from one end to the other end of the first opposing surface 43 in the width direction of the first axial movement limiting portion 35. The first opposing surface 43 is curved with a constant curvature over the entire first opposing surface 43 from one end to the other end in the width direction of the first axial movement limiting portion 35. That is, the entire first opposing surface 43 forms an arc shape with a constant curvature when viewed from a direction perpendicular to the axial direction of the support body 22 (the protruding direction of the first axial movement limiting portion 35).

The first opposing surface 44 is a surface of the first axial movement limiting portion 35 facing the opposite side to the first opposing surface 43, and is a concave surface curved along the first opposing surface 43. This first opposing surface 44 is continuously curved over the entire width direction of the first axial movement limiting portion 35 from one end to the other end of the first opposing surface 44 with the same constant curvature as the curvature of the first opposing surface curved portion 43a. In other words, the entire first opposing surface 44 forms an arc shape with a constant curvature when viewed from a direction perpendicular to the axial direction of the support body 22 (the protruding direction of the first axial movement limiting portion 35).

The first axial movement limiting portion 35 also has a first through hole 45 (see FIG. 7) that penetrates the first axial movement limiting portion 35 in the thickness direction from the first opposing surface 43 to the first opposite surface 44. The first through hole 45 is provided at the center position in the width direction of the first axial movement limiting portion 35, near the tip of the first axial movement limiting portion 35 in the protruding direction from the mountain side surface 22a of the support body 22.

The second axial movement limiting portion 36 is disposed across the receiving space 26 from the first axial movement limiting portion 35 in the axial direction of the support body 22. The second axial movement limiting portion 36 protrudes from the crest side 22a of the support body 22 on the opposite side of the first axial movement limiting portion 35 with respect to the receiving space 26 so as to limit the movement of the cable intermediate portion 3a received in the receiving space 26 to the opposite side of the first axial movement limiting portion 35 in the axial direction of the support body 22. That is, the second axial movement limiting portion 36 protrudes from the crest side 22a of the support body 22 on the ground G side of the receiving space 26 so as to limit the movement of the cable intermediate portion 3a received in the receiving space 26 to the ground G side. The second axial movement limiting portion 36 has a shape symmetrical to the first axial movement limiting portion 35. The second axial movement limiting portion 36 is made of a curved steel plate, similar to the first axial movement limiting portion 35, and is fixed by welding to the crest side surface 22a of the pillar body 22 in a position where it protrudes from the crest side surface 22a toward the crest side. The second axial movement limiting portion 36 has a second outer end surface 51, a pair of second side surfaces 52, a second opposing surface 53, and a second opposite surface 54.

The second outer end surface 51 is an end surface facing outward in the protruding direction of the second axial movement limiting portion 36 from the mountain side 22a of the pillar body 22, and is a surface that receives the wire mesh 6 stretched between a pair of terminal pillars 12. That is, the second outer end surface 51 is an end surface of the second axial movement limiting portion 36 facing the mountain side, and contacts the wire mesh 6 arranged on the mountain side. This second outer end surface 51 and the first outer end surface 41 are also end surfaces of the confinement portion 24 facing outward in the protruding direction of the confinement portion 24 from the mountain side 22a of the pillar body 22. The second outer end surface 51 has a second outer end surface curved surface portion 51a that is a convex surface curved so as to approach the pillar body 22 as it moves from the center of the width direction of the second axial movement limiting portion 36 perpendicular to both the axial direction of the pillar body 22 and the protruding direction of the second axial movement limiting portion 36 from the mountain side 22a of the pillar body 22. The second outer end surface curved portion 51a has an arc shape when viewed in the axial direction of the support body 22.

In this embodiment, the second outer end surface curved surface portion 51a extends over the entire second outer end surface 51. That is, the second outer end surface 51 is a continuously curved convex surface over the entire width direction of the second axial movement limiting portion 36 from one end to the other end of the second outer end surface 51. The second outer end surface 51 is curved with a constant curvature over the entire width direction of the second axial movement limiting portion 36 from one end to the other end of the second outer end surface 51. That is, the entire second outer end surface 51 forms an arc shape with a constant curvature when viewed from a direction along the axial direction of the support body 22.

The pair of second side surfaces 52 are surfaces of the second axial movement limiting portion 36 that face both outward in the width direction of the second axial movement limiting portion 36. One of the pair of second side surfaces 52 extends continuously from one end of the second outer end face 51 in the width direction of the second axial movement limiting portion 36 along the protruding direction of the second axial movement limiting portion 36 to the crest side surface 22a of the support body 22, and the other second side surface 52 extends continuously from the other end of the second outer end face 51 in the width direction of the second axial movement limiting portion 36 along the protruding direction of the second axial movement limiting portion 36 to the crest side surface 22a of the support body 22.

The second opposing surface 53 is a surface that faces the first opposing surface 43 of the first axial movement limiting portion 35 across the receiving space 26 in the axial direction of the support body 22. This second opposing surface 53 has a second opposing surface curved surface portion 53a that is a convex surface that curves away from the first axial movement limiting portion 35 as it moves from the center in the width direction of the second axial movement limiting portion 36 to both outside sides. The second opposing surface curved surface portion 53a has an arc shape when viewed from a direction perpendicular to the axial direction of the support body 22 (the protruding direction of the second axial movement limiting portion 36).

In this embodiment, the second opposing surface curved surface portion 53a extends over the entire second opposing surface 53. That is, the second opposing surface 53 is a continuously curved convex surface over the entire width direction of the second axial movement limiting portion 36 from one end to the other end of the second opposing surface 53. The second opposing surface 53 is curved with a constant curvature over the entire width direction of the second axial movement limiting portion 36 from one end to the other end of the second opposing surface 53. That is, the entire second opposing surface 53 forms an arc shape with a constant curvature when viewed from a direction perpendicular to the axial direction of the support body 22 (the protruding direction of the second axial movement limiting portion 36).

The second opposite surface 54 is a surface of the second axial movement limiting portion 36 facing the opposite side to the second opposing surface 53, and is a concave surface curved along the second opposing surface 53. This second opposite surface 54 is continuously curved over the entire width direction of the second axial movement limiting portion 36 from one end to the other end of the second opposite surface 54 with the same constant curvature as the curvature of the second opposing surface curved portion 53a. In other words, the entire second opposite surface 54 forms an arc shape with a constant curvature when viewed from a direction perpendicular to the axial direction of the support body 22 (the protruding direction of the second axial movement limiting portion 36).

The second axial movement limiting portion 36 has a second through hole 55 that penetrates the second axial movement limiting portion 36 in the thickness direction from the second opposing surface 53 to the second opposite surface 54. The second through hole 55 is provided at the center position in the width direction of the second axial movement limiting portion 36, and at a position near the tip of the second axial movement limiting portion 36 in the protruding direction from the mountain side surface 22a of the support body 22. The position where the second through hole 55 is provided is a position opposite the first through hole 45 in the direction along the axial direction of the support body 22.

The separation limiting portion 37 is installed between the first axial movement limiting portion 35 and the second axial movement limiting portion 36 so as to limit the movement of the cable middle portion 3a received in the receiving space 26 in the separation direction. This separation limiting portion 37 prevents the cable middle portion 3a from being separated from the receiving space 26 toward the mountain side. The separation limiting portion 37 is detachable from the first axial movement limiting portion 35 and the second axial movement limiting portion 36. Specifically, the separation limiting portion 37 has a bolt 60 that is inserted through the first through hole 45 and the second through hole 55 and installed between the first axial movement limiting portion 35 and the second axial movement limiting portion 36, and a nut 61 that is screwed into the bolt 60 to maintain the state in which the bolt 60 is installed between the first axial movement limiting portion 35 and the second axial movement limiting portion 36.

When the bolt 60 is inserted through the first through hole 45 and the second through hole 55 and installed between the first axial movement limiting portion 35 and the second axial movement limiting portion 36, it crosses the portion of the receiving space 26 near the tip end of the first and second axial movement limiting portions 35, 36 in the direction protruding from the mountain side surface 22a in the direction along the axial direction of the support body 22, thereby restricting the movement of the cable middle portion 3a in the receiving space 26 in the direction of separation. The head 60a of this bolt 60 is contained within the space surrounded by the curved first opposite surface 44.

The nut 61 is screwed onto the bolt 60 so as to prevent the bolt 60 from slipping out of the first through hole 45 and the second through hole 55 while the bolt 60 is inserted through the first through hole 45 and the second through hole 55, and to fix the bolt 60 to the first axial movement limiting portion 35 and the second axial movement limiting portion 36. The nut 61 and the end of the bolt 60 opposite the head 60a are contained within the space surrounded by the curved second opposing surface 54 of the second axial movement limiting portion 36.

When installing the rockfall prevention fence 1, the bolt 60 and nut 61 are removed from the first axial movement limiting section 35 and the second axial movement limiting section 36, and the cable middle section 3a can be inserted from the mountain side into the receiving space 26 between the first axial movement limiting section 35 and the second axial movement limiting section 36. After the cable middle section 3a is placed in the receiving space 26, the bolt 60 is inserted into the first through hole 45 and the second through hole 55, and the nut 61 is screwed onto the bolt 60 to fix the bolt 60 to the first and second axial movement limiting sections 35, 36 in a state where it is stretched between the first axial movement limiting section 35 and the second axial movement limiting section 36.

In this embodiment, when a falling rock strikes the rockfall prevention fence 1 from the mountain side and the wire mesh 6 and cable 3 are pulled toward the point of impact of the rockfall, the surfaces of the containment section 24 of the intermediate support 9 that rub against the wire mesh 6 and cable 3 are curved convex surfaces, which prevents the wire mesh 6 and cable 3 from getting caught in the containment section 24 and prevents the rockfall prevention fence 1 from being hindered in absorbing the impact energy of the falling rock.

Specifically, for example, as shown in Figure 8, when a falling rock 100 collides with the rockfall prevention fence 1 from the mountain side, the wire mesh 6 bends in the direction of collision of the falling rock 100, and the portions of the wire mesh 6 located on either side of the point of collision of the falling rock 100 are pulled toward the collision point and rub strongly against the first outer end face 41 of the first axial movement limiting portion 35 and the second outer end face 51 of the second axial movement limiting portion 36 of the containment portion 24 of the intermediate support 9. At this time, in this embodiment, the first outer end surface 41 has the first outer end surface curved surface portion 41a which is a convex surface curved so as to approach the support body 22 as it moves from the center to both outside in the width direction of the first axial movement limiting portion 35, and the second outer end surface 51 has the second outer end surface curved surface portion 51a which is a convex surface curved so as to approach the support body 22 as it moves from the center to both outside in the width direction of the second axial movement limiting portion 36, so that the wire mesh 6 slides without getting caught on the first outer end surface curved surface portion 41a and the second outer end surface curved surface portion 51a. Therefore, it is possible to prevent the wire mesh 6 from being restrained at the position of the confinement portion 24 by getting caught on the first outer end surface curved surface portion 41a and the second outer end surface curved surface portion 51a, and as a result, the impact energy of the falling rocks can be absorbed well using the entire wire mesh 6. Therefore, in this embodiment, it is possible to prevent the rockfall prevention fence 1 from being hindered in absorbing the impact energy of falling rocks due to the wire mesh 6 getting caught on the containment section 24.

Furthermore, when a falling rock 100 collides with the rockfall prevention fence 1 from the mountain side, the direction of impact of the falling rock 100 may be diagonally upward or diagonally downward. In such a case, the cable 3 of the rockfall prevention fence 1 bends in the direction of impact of the falling rock 100, and the portions of the cable 3 located on both sides of the point of impact of the falling rock 100 are pulled toward the point of impact, causing the cable middle portion 3a received in the receiving space 26 in the confinement portion 24 of the intermediate support 9 to rub strongly against the first opposing surface 43 of the first axial movement limiting portion 35 or the second opposing surface 53 of the second axial movement limiting portion 36. At this time, in the present embodiment, the first opposing surface 43 has a first opposing surface curved portion 43a which is a convex surface that curves away from the second axial movement limiting portion 36 as it moves from the center to both outside sides in the width direction of the first axial movement limiting portion 35, and the second opposing surface 53 has a second opposing surface curved portion 53a which is a convex surface that curves away from the first axial movement limiting portion 35 as it moves from the center to both outside sides in the width direction of the second axial movement limiting portion 36, so that the cable intermediate portion 3a slides without getting caught on the first opposing surface curved portion 43a and the second opposing surface curved portion 53a. This prevents the cable middle portion 3a from being restrained at the confinement portion 24 due to the first opposing surface curved portion 43a and the second opposing surface curved portion 53a getting caught, and as a result, the impact energy of the rockfall can be absorbed using the entire cable 3, and the impact energy of the rockfall can be transmitted to the brake elements 4 connected to both ends of the cable 3, and the impact energy can be effectively absorbed by those brake elements 4. Therefore, in this embodiment, it is possible to prevent the cable middle portion 3a from getting caught on the confinement portion 24, which hinders the rockfall fence 1 from absorbing the impact energy of the rockfall.

In this embodiment, the first outer end surface curved surface portion 41a extends over the entire first outer end surface 41, and the first outer end surface 41 is continuously curved over the entire first outer end surface 41 from one end to the other end in the width direction of the first axial movement limiting portion 35, and the second outer end surface curved surface portion 51a extends over the entire second outer end surface 51, and the second outer end surface 51 is continuously curved over the entire second outer end surface 51 from one end to the other end in the width direction of the second axial movement limiting portion 36. That is, the first outer end surface 41 and the second outer end surface 51 each have a continuous convex surface over their entirety. Therefore, when a falling rock hits the rockfall prevention fence 1 and the wire mesh 6 rubs against the first outer end surface 41 and the second outer end surface 51, the wire mesh 6 slides without getting caught at any point on the entire first outer end surface 41 and slides without getting caught at any point on the entire second outer end surface 51. This makes it possible to more effectively prevent the rockfall prevention fence 1 from being hindered from absorbing the impact energy of falling rocks.

In addition, even if the entire first outer end surface 41 and the entire second outer end surface 51 are curved convex surfaces, if the curvature of any part of the first outer end surface 41 is locally large, or if the curvature of any part of the second outer end surface 51 is locally large, there is a risk that the wire mesh 6 will get caught at the part where the curvature is large. In contrast, in this embodiment, the first outer end surface 41 is curved with a constant curvature over the entire first outer end surface 41 from one end to the other end in the width direction of the first axial movement limiting portion 35, and the second outer end surface 51 is curved with a constant curvature over the entire second outer end surface 51 from one end to the other end in the width direction of the second axial movement limiting portion 36, so that the wire mesh 6 does not get caught at the part where the curvature is large as described above. This makes it possible to more effectively prevent the rockfall prevention fence 1 from absorbing the impact energy of falling rocks.

In this embodiment, the first opposing surface curved portion 43a extends over the entire first opposing surface 43, and the first opposing surface 43 is continuously curved over the entire width direction of the first axial movement limiting portion 35 from one end to the other end of the first opposing surface 43, and the second opposing surface curved portion 53a extends over the entire second opposing surface 53, and the second opposing surface 53 is continuously curved over the entire width direction of the second axial movement limiting portion 36 from one end to the other end of the second opposing surface 53. In other words, the first opposing surface 43 and the second opposing surface 53 each have a continuous convex surface over their entirety. Therefore, when a falling rock hits the rockfall prevention fence 1 and the cable middle part 3a rubs against the first opposing surface 43, the cable middle part 3a slides without getting caught anywhere on the entire first opposing surface 43, and when a falling rock hits the rockfall prevention fence 1 and the cable middle part 3a rubs against the second opposing surface 53, the cable middle part 3a slides without getting caught anywhere on the entire second opposing surface 53. This makes it possible to more effectively prevent the rockfall prevention fence 1 from being hindered in absorbing the impact energy of the falling rock.

Even if the entire first opposing surface 43 and the entire second opposing surface 53 are curved convex surfaces, if the curvature of any part of the first opposing surface 43 is locally large or the curvature of any part of the second opposing surface 53 is locally large, there is a risk that the cable middle part 3a will get caught at the part where the curvature is large. In contrast, in this embodiment, the first opposing surface 43 is curved with a constant curvature over the entire first opposing surface 43 from one end to the other end in the width direction of the first axial movement limiting part 35, and the second opposing surface 53 is curved with a constant curvature over the entire second opposing surface 53 from one end to the other end in the width direction of the second axial movement limiting part 36, so that the cable middle part 3a will not get caught at the part where the curvature is high. This makes it possible to more effectively prevent the rockfall prevention fence 1 from impeding the absorption of the impact energy of falling rocks.

In addition, in this embodiment, as described above, when a rock falls and strikes the rockfall prevention fence 1, the wire mesh 6 and the cable middle part 3a slide without getting caught on the containment part 24, which has the effect of preventing the wire mesh 6 and the cable middle part 3a from being damaged by getting caught on the containment part 24.

In addition, in this embodiment, since the first opposite surface 44 of the first axial movement limiting portion 35 and the second opposite surface 54 of the second axial movement limiting portion 36 are each concave, the thickness of each of the first axial movement limiting portion 35 and the second axial movement limiting portion 36 can be reduced, and as a result, the weight and material cost of the first axial movement limiting portion 35 and the second axial movement limiting portion 36 can be reduced. In addition, since the thickness of the portion where the first through hole 45 of the first axial movement limiting portion 35 is provided and the thickness of the portion where the second through hole 55 of the second axial movement limiting portion 36 is provided can be reduced, the work of inserting the bolt 60 of the separation limiting portion 37 into the first through hole 45 and the second through hole 55 can be easily performed. Therefore, the work of installing the separation limiting portion 37 between the first axial movement limiting portion 35 and the second axial movement limiting portion 36 can be easily performed.

(Modification)
The intermediate support post for a rockfall prevention fence and the rockfall prevention fence according to the present invention are not necessarily limited to those described above. For example, the intermediate support post for a rockfall prevention fence and the rockfall prevention fence according to the present invention may have the following configurations.

The first outer end surface curved portion of the first axial movement limiting portion of the containment portion of the intermediate support for rockfall prevention fence is provided in a predetermined area extending inward from one end of the first outer end surface in the width direction of the first axial movement limiting portion, and a predetermined area extending inward from the other end of the first outer end surface, and the first outer end surface may have a flat portion between the first outer end surface curved portions on both sides. Figure 9 shows the structure near the first axial movement limiting portion of the containment portion of the intermediate support according to such a modified example.

In the structure according to this modified example, the first outer end surface 41 of the first axial movement limiting portion 35 of the confinement portion 24 has one first outer end surface curved portion 41a in a predetermined area extending inward from one end of the first outer end surface 41 in the width direction of the first axial movement limiting portion 35, the other first outer end surface curved portion 41a in a predetermined area extending inward from the other end of the first outer end surface 41 in the width direction of the first axial movement limiting portion 35, and a planar first outer end surface flat portion 41b provided between the first outer end surface curved portions 41a on both sides and continuous with the first outer end surface curved portions 41a on both sides.

Although not shown, in this modified example, the second outer end surface curved surface portion of the second axial movement limiting portion of the confinement portion is divided into a predetermined region extending from one end of the second outer end surface in the width direction of the second axial movement limiting portion to the inside, and a predetermined region extending from the other end of the second outer end surface to the inside, and the second outer end surface may have a flat portion between the second outer end surface curved surface portions on both sides. The shape of the second outer end surface in this modified example is the same as the shape of the first outer end surface 41 shown in FIG. 9.

Furthermore, the first outer end surface curved portion and the second outer end surface curved portion may each include a portion with a partially small curvature or a portion with a partially large curvature.

The first opposing surface curved surface portion of the first axial movement limiting portion may be divided into a predetermined region extending from one end of the first opposing surface to the inside in the width direction of the first axial movement limiting portion and a predetermined region extending from the other end of the first opposing surface to the inside, and the first opposing surface may have a planar portion between the first opposing surface curved surface portions on both sides. Similarly, the second opposing surface curved surface portion of the second axial movement limiting portion may be divided into a predetermined region extending from one end of the second opposing surface to the inside in the width direction of the second axial movement limiting portion and a predetermined region extending from the other end of the second opposing surface to the inside, and the second opposing surface may have a planar portion between the second opposing surface curved surface portions on both sides.

Furthermore, the first opposing surface curved portion and the second opposing surface curved portion may each include a portion with a partially small curvature or a portion with a partially large curvature.

The first opposing surface of the first axial movement limiting portion does not necessarily have to be a concave surface curved along the first opposing surface, and may be, for example, a flat surface or a concave surface with a shape other than that which follows the first opposing surface. Similarly, the second opposing surface of the second axial movement limiting portion does not necessarily have to be a concave surface curved along the second opposing surface, and may be, for example, a flat surface or a concave surface with a shape other than that which follows the second opposing surface.

The first axial movement limiting section does not necessarily have to have a first side surface facing both widthwise outward of the first axial movement limiting section between each of the ends of the first outer end surface in the width direction of the first axial movement limiting section and the support body, and the curved first outer end surface curved surface portion may be directly connected to the outer surface (ridge side) of the support body. Similarly, the second axial movement limiting section does not necessarily have to have a second side surface facing both widthwise outward of the second axial movement limiting section between each of the ends of the second outer end surface in the width direction of the second axial movement limiting section and the support body, and the curved second outer end surface curved surface portion may be directly connected to the outer surface (ridge side) of the support body.

The rockfall prevention fence of the present invention is not necessarily limited to being installed on the side of a road, but may be installed on a mountain slope to catch rocks falling from the mountain side. In this case, the mountain side corresponds to the upper side of the mountain slope, and the side opposite the mountain side corresponds to the lower side of the mountain slope.

1 Rockfall prevention fence 2 Supports on both sides 3 Cable 3a Cable intermediate portion 6 Wire mesh 9 Intermediate support 22 Support main body 24 Confinement portion 26 Receiving space 35 First axial movement restriction portion 36 Second axial movement restriction portion 37 Separation restriction portion 41 1 outer end surface 41a 1st outer end surface curved surface portion 43 1st opposing surface 43a 1st opposing surface curved surface portion 44 1st opposing surface 45 1st through hole 51 2nd outer end surface 51a 2nd outer end surface curved surface portion 53 2nd opposing surface 53a Second opposing surface curved surface portion 54 Second opposing surface 55 Second through hole 60 Bolt 61 Nut

Claims (8)

A rockfall prevention fence includes a cable stretched between a pair of side supports installed at a distance from each other and a wire mesh fixed to the cable in a manner that covers the area between the pair of side supports, and is used in a rockfall prevention fence that receives rocks falling from a mountain side, and is installed between the pair of side supports on the opposite side to the mountain side with respect to the wire mesh in order to support a cable middle section that is the middle section between both ends of the cable,
A support body that is erected on the ground;
A first axial movement limiting portion and a second axial movement limiting portion are provided on the outer surface of the support body so as to protrude from the outer surface of the support body,
The first axial movement limiting portion and the second axial movement limiting portion protrude from the outer surface of the strut body on one side of the receiving space in the axial direction of the strut body and on the opposite side to the one side, respectively, so as to define a receiving space that receives the cable intermediate portion,
the first axial movement limiting portion has a first outer end surface facing outward in a protruding direction of the first axial movement limiting portion from an outer surface of the pillar body, and the first outer end surface has a first outer end surface curved surface portion that is a convex surface curved so as to approach the pillar body as it moves toward both outer sides in a width direction of the first axial movement limiting portion that is perpendicular to both the axial direction of the pillar body and the protruding direction of the first axial movement limiting portion,
The second axial movement limiting portion has a second outer end surface facing outward in the protruding direction of the second axial movement limiting portion from the outer surface of the pillar main body, and the second outer end surface has a second outer end surface curved portion which is a convex surface that curves closer to the pillar main body as it moves toward both outside in the width direction of the second axial movement limiting portion, which is perpendicular to both the axial direction of the pillar main body and the protruding direction of the second axial movement limiting portion. The intermediate support for rockfall prevention fences according to claim 1, further comprising a separation limiting part installed between the first axial movement limiting part and the second axial movement limiting part so as to limit the movement of the cable intermediate part received in the receiving space in a separation direction, the separation direction being perpendicular to the axial direction of the support body and away from the support body. The intermediate support for a rockfall prevention fence according to claim 1, wherein the first axial movement limiting portion further has a first opposing surface that faces the second axial movement limiting portion across the receiving space, and the first opposing surface has a first opposing surface curved surface portion that is a convex surface that curves away from the second axial movement limiting portion as it moves toward both outside sides in the width direction of the first axial movement limiting portion. The intermediate support for rockfall prevention fences according to claim 1 or 3, wherein the second axial movement limiting portion further has a second opposing surface that faces the first axial movement limiting portion across the receiving space, and the second opposing surface has a second opposing surface curved surface portion that is a convex surface that curves away from the first axial movement limiting portion as it moves toward both outside sides in the width direction of the second axial movement limiting portion. A rockfall prevention fence that catches rocks falling from the mountain side,
A pair of side supports spaced apart from each other;
A cable stretched between the pair of side supports;
a wire mesh fixed to the cable in a state covering the area between the pair of side supports;
a middle support pillar installed on the opposite side to the mountain side with respect to the wire mesh between the pair of side supports to support a middle section of the cable that is a middle section between both ends of the cable;
The intermediate support has a support body that is erected on the ground, and a first axial movement limiting portion and a second axial movement limiting portion that are installed on the outer surface of the support body so as to protrude from the outer surface of the support body,
The first axial movement limiting portion and the second axial movement limiting portion protrude from the outer surface of the strut body on one side and the other side of the receiving space in the axial direction of the strut body, respectively, so as to define a receiving space that receives the cable intermediate portion,
the first axial movement limiting portion has a first outer end surface facing outward in a protruding direction of the first axial movement limiting portion from an outer surface of the pillar body, and the first outer end surface has a first outer end surface curved surface portion that is a convex surface curved so as to approach the pillar body as it moves toward both outer sides in a width direction of the first axial movement limiting portion that is perpendicular to both the axial direction of the pillar body and the protruding direction of the first axial movement limiting portion,
A rockfall prevention fence, wherein the second axial movement limiting portion has a second outer end surface facing outward in the protruding direction of the second axial movement limiting portion from the outer surface of the pillar main body, and the second outer end surface has a second outer end surface curved portion which is a convex surface curved so as to approach the pillar main body as it moves toward both outside sides in the width direction of the second axial movement limiting portion, which is perpendicular to both the axial direction of the pillar main body and the protruding direction of the second axial movement limiting portion. The rockfall prevention fence according to claim 5, wherein the intermediate support further has a separation limiting part installed between the first axial movement limiting part and the second axial movement limiting part so as to limit the movement of the cable intermediate part received in the receiving space in the separation direction, and the separation direction is perpendicular to the axial direction of the support body and away from the support body. The rockfall prevention fence according to claim 5, wherein the first axial movement limiting portion further has a first opposing surface that faces the second axial movement limiting portion across the receiving space, and the first opposing surface has a first opposing surface curved surface portion that is a convex surface that curves away from the second axial movement limiting portion as it moves toward both outside sides in the width direction of the first axial movement limiting portion. The rockfall prevention fence according to claim 5 or 7, wherein the second axial movement limiting portion further has a second opposing surface that faces the first axial movement limiting portion across the receiving space, and the second opposing surface has a second opposing surface curved surface portion that is a convex surface that curves away from the first axial movement limiting portion as it moves toward both outside sides in the width direction of the second axial movement limiting portion.