JP2004027635A - Stone fall protective fence - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stone fall protective fence that can positively stop a falling stone without escaping to the lower part of a slope. <P>SOLUTION: In this stone fall protective fence 10 constituted by stretching a protective net 30 between posts 20, 20 erected at a prescribed space, the post 20 is curved, and the tip of each post 20 is bent toward the impact receiving side. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rockfall protection fence that attenuates kinetic energy of rockfall and reliably stops rockfall.
[0002]
[Conventional device]
As a protection measure against falling rocks, a protective net such as a wire rope or wire mesh is stretched between straight supports erected on the slope at predetermined intervals, and between the upper part of each support and the anchor provided on the upper slope. Rock fall fences connected with stay ropes have long been known.
[0003]
[Problems to be solved by the invention]
The conventional rock fall fence has the following problems.
<B> At the time of the impact, the pillars are deformed to the downstream side of the slope and become lower from the surface of the ground, and the falling rocks rise along the protective net due to the rotation of the falling rocks. There was a problem of getting over the rockfall protection fence.
<B> As a preventive measure, a rock fall protection fence may be provided high in advance, but in this case, the cost is high.
<C> As a method for suppressing the climbing of the falling rock c, a method of inclining the protective fence a upwardly on the slope as shown in FIG. 6 can be considered. In this method, the collision force of the falling rock c concentrates on the lower part of the protective fence a and escapes from below the protective net b.
<D> The protection net stretched in a planar shape has a large deformation amount due to the collision of the falling rock, and the effective height from the ground surface is low, which causes the falling rock to escape downward.
In addition, when the spacing between the supports is increased in this embodiment, the deformation of the protective net becomes more remarkable, so that the spacing between the supports cannot be increased. Therefore, it is necessary to increase the construction labor and increase the cost.
[0004]
[Object of the invention]
The present invention has been made in view of the above points, and an object of the present invention is to provide a rock fall protection fence capable of reliably preventing falling rocks by simple means.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the rock fall protection fence of the present invention is a rock fall protection fence constructed by extending a protection net between pillars erected at predetermined intervals, wherein the pillars are curved. And the tip of each of the columns is bent toward the receiving side.
Here, the receiving side refers to the side where the falling rock collides, and in the case of the inclined surface, refers to the upstream side of the slope.
[0006]
Further, the present invention is characterized in that, in the rock fall protection fence described above, the protection net is stretched along the shape of the column.
[0007]
Also, the present invention is characterized in that, in the rock fall protection fence described above, an anchor is provided on an upper part of an inclined surface on which the rock fall protection fence is installed, and a stay rope is connected between the upper part of the pillar and the anchor.
Here, the upper portion of the support is not limited to the tip of the support, but refers to a position where a stay rope can be connected to effectively achieve the stability of the support.
[0008]
Further, the present invention is characterized in that, in the rock fall protection fence described above, an anchor is provided at a lower part of the slope where the rock fall protection fence is installed, and a stay rope is connected between the upper part of the pillar and the anchor.
[0009]
Further, the present invention is characterized in that, in the rock fall protection fence described above, a shock absorber is arranged on the way of the stay rope.
Here, the shock absorber absorbs the impact force of the rock falling on the rock fall protection fence.For example, when the shock absorber is arranged on a stay rope, when a certain degree of tension acts, the shock absorber starts sliding on the rope and frictional resistance is reduced. Means to absorb the energy of tension.
[0010]
Further, the present invention is characterized in that, in the rock fall protection fence described above, a lower portion of the column is pivotally supported via a hinge so that the column can be tilted without transmitting a bending moment to the column.
[0011]
Further, in the rock fall protection fence according to the present invention, in the rock fall protection fence, the means for erection of the rock fall protection fence are connected by a support rope to each mooring material installed on the upper and lower slopes where the rock fall protection fence is installed and the lower part of the support, The upper part of the support and each mooring material are connected by stay ropes.
Here, the mooring member refers to a member such as an anchor capable of transmitting a force transmitted from a support rope to a slope.
[0012]
Further, the present invention is characterized in that in the rock fall protection fence described above, a shock absorber is arranged on the way of the support rope.
[0013]
Embodiment 1 of the present invention
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
<A> Overall Configuration FIG. 1 shows a side view of a rock fall protection fence 10.
The rock fall protection fence 10 is composed of a pillar 20 erected at a predetermined interval and a protection net 30 stretched between the pillars 20.
Each strut 20 is curved in an arc shape, and its tip stands up toward the receiving side.
[0015]
The protection net 30 is fixed along the shape of each column 20, and restricts the deformation direction of the protection net 30.
The surface on which the protective net 30 is formed is composed of a straight portion 31 and a curved portion 32, like the support column 20, and the upper side of the curved portion 32 is disposed facing the inclined upper portion.
[0016]
Further, in this example, the case where the upper part of the support 20 is connected to the anchor 41 provided on the upper part of the inclined surface H by the stay rope 40 is shown. However, the present invention is not limited to this mode. H may be connected to the anchors 41 provided on the upper and lower portions, respectively, or the stay rope 40 may not be used.
Further, as shown in FIG. 1, a buffer 42 may be arranged on the stay rope 40.
In addition, the extending | stretching form of the protection net 30 is not limited to the above, For example, it shows in Embodiments 4 and 5 as other forms.
[0017]
<B> Supports The support 20 is a rigid member that propagates and supports the collision force of the falling rock S received by the protection net 30 to the inclined surface H, and is continuous with the straight portion 21 installed in the ground and the straight portion 21. And a curved portion 22 formed by the bending.
The struts 20 are curved in an arc shape, and the tips of the struts 20 stand upright on the inclined surface H.
[0018]
The support 20 may use various known rigid structures such as H steel, but it is preferable to use a support 20 having a composite structure of steel and concrete as described below.
For example, an unbonded type PC steel material is arranged in a steel pipe, and concrete is filled in the steel pipe to form a column 20.
The PC steel material is arranged on the tension side inside the steel pipe, that is, near the inside of the bending diameter, and after filling and consolidating the concrete, supporting plates are arranged at both ends and fixed with a stopper or the like.
If a tension is introduced into the PC steel material in advance when the column 20 is deformed instead of introducing a tension in advance, the load-carrying capacity and the deformation capability of the column 20 are significantly improved. .
[0019]
The column 20 may be erected in a hole of a foundation block installed at a predetermined interval on the inclined surface H, or the column 20 may be provided in advance in the basic block and installed at a predetermined interval on the inclined surface H. Good. At this time, the upright posture of the column 20 is set such that the linear portion 21 is substantially perpendicular to the normal direction of the inclination, and preferably downward of the slope.
[0020]
Note that the curved portion 22 does not necessarily have to have a constant curvature, and may have a changed curvature or a polygonal shape.
Further, the bending portion 22 may extend over the entirety, and this embodiment will be described in a sixth embodiment.
[0021]
<C> Protective net The protective net 30 receives the impact force directly or indirectly from the rock fall S and buffers the impact force to stop the rock fall S. For example, a rope material, a net material or a combination thereof is known. Can be used.
[0022]
The protection net 30 is processed into a unit body having a predetermined size in advance so that the mounting work by human power becomes easy, so that the fixing work to the support 20 or the fixing work between the protection nets 30 and 30 can be performed on an inclined surface with a poor scaffold. H can be easily performed. At this time, a conventionally used fixing bracket or the like can be used as the fixing bracket that holds them together.
Further, a buffer 42 may be provided on the way.
[0023]
[Action]
Hereinafter, the operation of the rock fall protection fence 10 will be described with reference to the drawings.
[0024]
<B> Absorption of Collision Energy Rockfall S has not only kinetic energy but also rotational kinetic energy at the time of collision with rockfall protection fence 10.
[0025]
Kinetic energy of the falling rock S colliding with the protection net 30 is buffered by the tensile strength of the protection net 30 and the rigidity of the column 20.
[0026]
Explaining this damping action in more detail, the kinetic energy of the falling rock S is changed to collision energy while being buffered by the collision with the protection net 30. When this exceeds a certain value, the column 20 starts to deform, and the damping action by the deformation of the column 20 proceeds. At this time, a prestress is also introduced into the PC steel material inside the column 20 due to the deformation, so that the collision energy can be efficiently attenuated.
[0027]
<B> Override prevention action At the same time, a turning force is generated in the rock fall S by rotational kinetic energy, and the rock fall S rises along the protection net 30 (see FIG. 2).
For example, when the falling rock S collides with the straight portion 31 below the column 20, the falling rock S moves while rotating from the straight portion 31 to the curved portion 32, and gradually changes the traveling direction to above the inclined surface H.
The energy of the falling rock S is attenuated by conversion into frictional force generated between the protective nets 30 and potential energy.
Due to the energy decay, the ease of installation of the rock fall S and the protection net 30 gradually weakens.
The falling rock S jumps out from the upper end of the protective net 30 or from the middle thereof toward the inclined surface H (see FIG. 3).
[0028]
As described above, the falling rock S gradually moves along the protective fence along the protective fence as it moves, so that it can be prevented from climbing over the protective fence.
For this reason, it is not necessary to incline the erected direction toward the upper side of the slope as in the case of the conventional column 20, and it is also possible to avoid the risk of falling rocks S from the lower side of the protective fence.
The falling rock S1 draws radiation and is repelled to the upstream side of the slope.
As described above, the present invention can prevent the climbing over the fence and the escape from below the protection net 30 by repelling by utilizing the rotational kinetic energy of the falling rock S.
[0029]
Embodiment 2 of the present invention
The case where the anchoring of the support 20 to the inclined surface H is a rigid connection has been described above, but FIG. 4 shows that the support rope 50U is attached to the mooring members 51U and 51D provided below the support 20 above and below the rock fall protection fence 10. , 50D, and the upper end of the column 20 is connected to each of the mooring members 51U, 51D by staying ropes 40U, 40D.
This fixing method does not require the length of the support pillar 20 to enter the slope, which leads to a reduction in member cost and a reduction in the cost of drilling the slope, which is economical.
[0030]
Third Embodiment of the Invention
In addition, as a method of not fixing the column 20 rigidly, there is a method of pivotally supporting the fixing section with a hinge, which is used together with the stay rope 40 (not shown).
In this case, the impact force of the falling rock S is not absorbed by the bending deformation of the column 20, the column 20 is only passive, and the shock absorber 42 arranged on the stay rope 40 acts on sliding resistance to attenuate the impact force. The buckling of the support 20 is prevented, and the exchangeability of the support 20 is improved.
These methods are particularly effective in places where the ground strength is low.
[0031]
Embodiment 4 of the present invention
FIG. 5 shows another embodiment in which the protection net 30 is stretched.
In this example, the protection net 30 is bridged over the front end between the columns 20, 20, and the net surface forms a plane in a substantially vertical direction.
For this reason, an arcuate space is formed between the pillar 20 that is bent and erected and the surface of the protective net 30.
[0032]
When the falling rock S collides with the protection net 30, the falling rock S is dragged by the protection net 30 and moves.
When the protection net 30 that moves together with the falling rock S is pressed against the nearby posts 20, 20, the surface of the protection net 30 forms a straight portion 31 and a curved portion 32 having substantially the same shape as the support 20.
Then, as in the above-described embodiment, the falling rock S rises along the surface and rebounds upward on the slope.
At this time, the lower part of the protection net 30 is provided with a certain extra length to prepare for protection of the falling rock S that falls.
In this example, it is easy to stretch the protection net 30 and prevent direct hitting of the pillar 20 by the falling rock S. Since the falling rock S is once wrapped in the protection net 30 and moves, the pillar 20 is moved. There is an advantage that the impact on the vehicle is reduced.
[0033]
Embodiment 5 of the present invention
Further, the protective net 30 may be stretched below the support 20 with respect to the inclined surface, that is, on a curved portion on the outside where the support 20 is bent (not shown).
[0034]
Embodiment 6 of the present invention
Moreover, the support | pillar 20 does not have the linear part 31, It is good also as a form which comprises the curved part 22 over the whole (not shown).
In the present embodiment, the receiving force received by the column 20 can be reduced.
This is because it is possible to provide a stretched surface of the protection net 30 that does not cause a sudden change in the direction of movement of the falling rock S. That is, the angle difference between the movement direction of the falling rock S and the surface of the protection net 30 can be set small.
As a result, the kinetic energy of the falling rock S is not attenuated by the collision with the protective fence, and the large rock S moves along the protective fence while retaining the kinetic energy and jumps out from around the tip.
Therefore, the falling rock S has a momentum, and it can be expected that a great deal of energy can be offset by the collision with the falling rock S that subsequently falls.
[0035]
【The invention's effect】
According to the present invention, as described above, the following effects can be obtained.
<B> By providing the support with the curved portion, the falling rock climbing up the fence changes its movement direction to the upper side of the slope, so that the falling rock can be reliably stopped without climbing over the falling rock protection fence.
<B> When stopping falling rocks, it is not necessary to increase the length of the columns, so that the cost is not increased.
<C> Since there is no need to incline the protective fence toward the upper part of the slope, there is little risk of falling rocks falling out of the lower part of the protective net.
<D> Since the stretched surface of the protective net of the present invention is curved, the amount of deformation of the protective net due to a falling rock collision is small, and there is no need to worry about a decrease in the height for catching the falling rock. Therefore, maintenance can be always performed safely.
In addition, since the protection net has a small deformation at the time of the falling rock collision, the pitch between the pillars can be increased, which is economical.
<E> Further, when the strut is deformed with the base as a fulcrum on the downstream side of the slope due to the fall of the rock, the height from the ground surface to the tip of the strut is further increased, and the rock can be caught in a wider range.
<F> The rock climbing up the fence, and the falling rocks collide with the falling rocks, offsetting the kinetic energy and reducing the impact on the rock fall protection fence. it can.
[Brief description of the drawings]
FIG. 1 is an implementation side view of the present invention.
FIG. 2 is a side view in which rock fall moves along a rock fall protection fence.
FIG. 3 is a side view in which a falling rock jumps out of a falling rock protection fence.
FIG. 4 is a side view showing another embodiment of fixing to an inclined surface according to the present invention.
FIG. 5 is a side view in a case where the protection net is stretched by another method.
FIG. 6 is an implementation side view of a conventional protection net.
[Explanation of symbols]
10. Rock fall protection fence 20 ・ Strut 21 ・ ・ Straight part 22 ・ ・ Bending part 30 ・ ・ Protection net 40 ・ ・ Staying rope 41 ・ ・ Anchor 42 ・ ・ Bumper 50 ・ ・ Support rope 51 ・ ・ Mooring part

Claims (1)

In rockfall fences constructed by extending a protective net between columns erected at predetermined intervals,
Said struts are curved,
The tip of each of the columns is bent toward the receiving side,
Rockfall protection fence.

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