JP6994235B2 - Avalanche prevention fence and its installation method - Google Patents

Description

The present invention relates to an avalanche prevention fence for preventing avalanches occurring on slopes in snowfall areas and ensuring the safety of houses and traffic, and in particular, an avalanche prevention fence capable of suppressing the formation of a cornice that induces an avalanche. Regarding the installation method.

In snowfall areas and heavy snowfall areas, when an avalanche occurs on a slope, not only is the fallen snow mass blocking road and railroad traffic, but it is also a man-made accident. Therefore, multiple avalanche prevention fences have been erected on slopes facing roads and railroads to prevent avalanches from closing roads and damaging houses.

3 and 10 to 12 show a conventional avalanche prevention fence 21 (hereinafter referred to as a prevention fence 21). The preventive fence 21 is a pair of columns 22 and 22 erected on the slope G, a fall prevention body 23 provided between the lower end side of each column 22 and the slope G, and a steel pipe between the columns 22 and 22. The cross beam members 24A, 24A, ... A flat snow stopper 24, an X-shaped brace 25 on the columns 22 and 22 facing the snow stopper 24, and a substrate 26 fixed to and supported by the column 22 and the fall prevention body 23. It is roughly composed of a preventive fence support mechanism 27 that is supported by a support wire or the like from above the slope G.
An avalanche prevention fence having a similar configuration is shown in FIG. 5 of Patent Document 1.

Japanese Patent No. 6113474

As shown in FIG. 10, the above-mentioned preventive fence 21 has a structure in which the snow stopper portion 24 is formed in a flat shape from the upper end to the lower end of the support column 22 and installed substantially perpendicular to the slope G. Since snow is easily deposited in the snow-stopping region X having a substantially V-shaped vertical cross section formed by the snow-stopping portion 24, the weight increases and the snow density increases as the amount of snowfall accumulates. Furthermore, the snow density of the snow layer becomes higher because the snow settles and the snow pressure is applied downward. Further, by applying the snow pressure due to the snow layer sliding downward on the slope G, the snow density is high in the snow stop region X, and a tightly packed snow layer is formed.

Further, the principle of forming a cornice from the snow model shown in FIG. 11 and the snow condition shown in FIG. 12 will be described. In FIG. 11, when the preventive fence 21 is installed on the slope G where the snow is deposited up to the height indicated by the alternate long and short dash line L without the preventive fence 21 installed, the preventive fence 21 is deposited on the back surface (valley side surface) side. _The formation of the snow layer S1 is blocked by the preventive fence 21 and is deposited on the front surface (mountain side surface) _side of the preventive fence 21 to form the snow layer S2. Since the snow layer S ₂ on the front side of the preventive fence 21 has twice the amount of snow, as the snowfall continues, the snow layer S ₂ exceeds the preventive fence 21 as shown in FIG. A cornice is formed up to the height.
If the snow continues to accumulate from this state, the cornice will grow further, and eventually it will become a curl in a state of being caught in the valley side from the upper end of the preventive fence 21.

The formed cornice and rolls grow and fall due to their weight increase, reach the roads and railroad tracks, cause traffic obstacles, and cause problems such as inducing avalanches in the snow layer on slope G. ing.
In order to prevent this problem, it is necessary to remove the cornice and rolls at an early stage. There is a problem that the snow removal cost increases due to the request for a short work period.

The present invention has been made in view of the above-mentioned problems of the prior art, and a large snow layer is formed by dispersing the amount of snow accumulated between the slope and the avalanche prevention fence and causing a part of the snow to flow out. The purpose is to provide an avalanche prevention fence and its installation method to prevent snow damage such as cornice and avalanche formation and growth, and to prevent avalanche damage caused by falling cornice and cornice. do.

(1) The means of the present invention according to claim 1 configured to solve the above-mentioned problems is an avalanche prevention fence provided with a valley-side avalanche preventive body and a mountain-side avalanche preventive body, and the valley-side avalanche preventive body. Is a pair of valley-side columns that are erected laterally apart on a slope, and a valley-side avalanche portion that is formed by horizontally arranging a plurality of cross beam members on the upper side of the pair of valley-side columns. The mountain-side avalanche preventive body is composed of an opening formed on the lower side of the valley-side snow stopper, and the mountain-side avalanche preventive body includes a pair of mountain-side columns standing laterally separated on the slope and a plurality of mountain-side columns on the pair of mountain-side columns. The mountain-side avalanche preventive body is composed of a mountain-side avalanche preventive body formed by horizontally arranging the cross beam material of the book, and the mountain-side avalanche preventive body is opposed to the valley-side avalanche preventive body in a state where the mountain-side snow stop portion faces the opening. It is located above the slope so as to be separated from each other.
(2) Then, the mountain-side avalanche preventive body may be arranged above the slope with an interval corresponding to half the height of the valley-side support with respect to the valley-side avalanche preventive body.
(3) Further, it is preferable that the valley-side avalanche prevention body utilizes a part of the structure of the existing avalanche prevention fence already installed on the slope.
(4) Further, in the means constituting the present invention according to claim 4, a pair of valley-side columns are erected laterally apart on the slope, and a cross beam member is laterally placed on the upper side of the pair of valley-side columns. A valley-side avalanche preventive body is installed by the process of forming an opening on the lower side of the valley-side snow stop portion by forming a valley-side snow stop portion, and above the slope above the valley-side avalanche preventive body. A pair of mountain-side columns are erected at a distance from each other in the lateral direction, and a mountain-side avalanche prevention body is installed by the process of horizontally arranging multiple cross beam members on the pair of mountain-side columns to form a mountain-side snow stopper. The process comprises a step of arranging the mountain-side avalanche preventive body at a distance above the slope with respect to the valley-side avalanche preventive body in a state where the mountain-side snow stop portion faces the opening.

Since the present invention is configured as described above, it has the following effects.
(1) The avalanche prevention fence is divided into a valley-side avalanche prevention body with an opening on the lower side and a mountain-side avalanche prevention body separated above the slope to disperse the amount of snow. It is possible to suppress the formation of snow cornice by suppressing the snow accumulation condition in which the formation of snow is formed.
(2) Since the mountain-side avalanche preventive body was placed above the slope with an interval corresponding to half the height of the valley-side support with respect to the valley-side avalanche preventive body, the amount of snow accumulated was effectively dispersed. It is possible to suppress the formation of avalanches.
(3) The valley-side avalanche preventive body has an opening on the lower side so that part of the snow accumulated between the valley-side avalanche preventive body and the mountain-side avalanche preventive body flows out to the valley side. It is possible to prevent the formation of a large snow layer between the body and the avalanche prevention body on the valley side, and it is possible to prevent the formation of a cornice.
(4) The valley-side avalanche prevention body can be easily installed on the slope by using a part of the existing avalanche prevention fence that has already been installed on the slope, and the construction period and installation cost. Can be saved.

1 to 9 relate to an embodiment of the present invention, and FIG. 1 is a perspective view showing an overall configuration of an avalanche prevention fence. It is a side view of an avalanche prevention fence. FIGS. 3 to 6 show a process of creating an avalanche prevention fence according to an embodiment from an existing avalanche prevention fence, and FIG. 3 is an explanatory diagram for removing a part of a snow stopper and a fall prevention body from the existing avalanche prevention fence. Is. It is explanatory drawing which attaches the interval forming body to the valley side avalanche prevention body. It is a perspective view of the space forming body provided with the mountain side support. It is explanatory drawing which attaches the cross beam material to the mountain side support. It is explanatory drawing of the principle which suppresses the formation of a cornice. It is explanatory drawing of the snow accumulation model by an avalanche prevention fence. It is explanatory drawing of the snow accumulation situation by an avalanche prevention fence. 10 to 12 relate to the prior art, and FIG. 10 is an explanatory diagram of the principle of forming a cornice by an avalanche prevention fence. It is explanatory drawing of the snow accumulation model by an avalanche prevention fence. It is explanatory drawing of the snow accumulation situation by an avalanche prevention fence.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 9. In the figure, 1 is an avalanche prevention fence installed on the slope G, and 2 is a valley-side avalanche prevention body constituting the avalanche prevention fence 1. Reference numerals 3 and 3 indicate a pair of left and right valley-side columns constituting the valley-side avalanche prevention body 2, and the pair of valley-side columns 3 and 3 are made of H-shaped steel material having a length of about 1,500 mm and are ribbed on one side. A plurality of bolt holes 3B, 3B, ... (Not shown) are bored in 3A at predetermined intervals in the vertical direction.

Reference numeral 4 denotes a valley-side snow stopper erected between the pair of valley-side columns 3 and 3, and the valley-side snow stopper 4 is composed of steel pipes vertically separated from the valley-side columns 3 and 3 on the upper side. The cross beam members 4A, 4A, and 4A of the book are horizontally installed, and both ends are fastened to the valley side column 3 with a fastener 4B for screwing a nut into a U-shaped bolt inserted into the bolt hole 3B. There is.
By installing the valley-side snow stopper 4 only on the upper side of the pair of valley-side columns 3 and 3, the valley-side avalanche prevention body 2 has an opening on the lower side having substantially the same area as the valley-side snow stopper 4. The part 5 is formed.

Reference numeral 6 indicates a mountain-side avalanche preventive body installed away from the valley-side avalanche preventive body 2 on the mountain side. 7 and 7 are a pair of mountain-side columns constituting the mountain-side avalanche prevention body 6, and each mountain-side column 7 is made of H-shaped steel material having a length of about 750 mm, and as shown in FIG. 5, one side of each mountain-side column 7. A plurality of bolt holes 7B, 7B, ... Are bored in the rib 7A.

8 constitutes a mountain-side avalanche prevention body 6 and is a mountain-side snow stopper provided between the pair of mountain-side columns 7 and 7. The mountain-side snow stopper 8 is vertically separated from the mountain-side columns 7 and 7 and is a steel pipe material. Three cross beam members 8A, 8A, 8A made of the above are horizontally installed, and both ends are fastened to the mountain side columns 7 and 7 with a fastener 8B for screwing a nut into a U-shaped bolt inserted into the bolt hole 7B. Is formed. A brace 9 is stretched on the upper side facing the snow stopper 4 between the pair of valley-side columns 3 and 3 to provide strength.

Reference numerals 10 and 10 indicate a pair of left and right spacing forming bodies for arranging the mountain-side avalanche prevention body 6 at a distance above the slope G with respect to the valley-side avalanche prevention body 2. Each of the interval forming bodies 10 is made of an H-shaped steel material, and is made of an upper support material 10A and a lower support material 10B to which a mountain side support 7 is fixed to one side end by a welding means, and a T-shaped steel material, and the upper support material 10A and the lower side. A channel steel material fixed to the other end side of the support material 10B by welding means and fastened to the valley side column 3 with bolts and nuts, and a grooved steel material fixed to both sides of the lower support material 10B with the lower end side protruding. It is composed of a pair of leg members 10D and 10D.

The mountain-side avalanche preventive body 6 is arranged above the slope G with an interval corresponding to half the height of the valley-side support 3 with respect to the valley-side avalanche preventive body 2 to disperse the amount of snow. In the present embodiment, the lengths of the upper and lower support members 10A and 10B are set to about 641 mm, and the height is 1,500 mm from the rear surface of the valley side column 3 to the rear surface of the mountain side column 7. That is, the distance between the valley side snow stopper 4 and the mountain side snow stopper 8 is set to about 750 mm.

Reference numeral 11 is a steel plate substrate for integrally installing the valley-side avalanche preventive body 2, the interval forming body 10, and the mountain-side avalanche preventive body 6 on the slope G. By erecting 11A and 11A diagonally upward, installation on the slope G is facilitated. The substrate 11 has strength by integrally supporting the valley side avalanche prevention body 2 and the mountain side avalanche prevention body 6 on the lower side by fixing the lower ends of the valley side support 3 and the leg members 10D and 10D by welding means. And has stability.

12 and 12 show a pair of left and right preventive fence support mechanisms that support the avalanche preventive fence 1 in a substantially vertical state on the slope G. Reference numeral 13 is a lower traction tool constituting each of the preventive fence support mechanisms 12, and the lower traction tool 13 includes a wire locking pin 13A provided on a bracket fixed to the lower end side of the valley side column 3 and the wire locking. It is composed of a lower support wire 13 having one end side engaged with the pin 13A and an annular connecting portion 13B provided on the other end side.

Reference numeral 14 denotes an upper traction tool constituting the preventive fence support mechanism 12, and the upper traction tool 14 has a wire locking pin 14A provided on a bracket fixed to the upper side of the valley side support 3 and one end to the wire locking pin 14A. It is composed of an upper support wire 14B in which the side is engaged and the other end side is connected to the other end side of the lower support wire 13B.
Then, in the preventive fence support mechanism 12 having the above configuration, the upper end side is fixed to the ground with an anchor, the lower end side is connected to the other end side of the lower support wire 13, and the length of the support rope 15 is adjusted. As a result, the avalanche prevention fence 1 is installed substantially perpendicular to the slope G.

Since the avalanche prevention fence 1 according to the present embodiment is a new product having the above-mentioned configuration, the valley side avalanche prevention body 2, the mountain side avalanche prevention body 6 and the interval forming body 10 are newly created and installed. However, from the viewpoint of effective use of materials, shortening of construction period and cost reduction, we came up with the idea of utilizing the existing avalanche prevention fence. The modification process will be described in detail below with reference to FIGS. 2 to 5.

The existing avalanche prevention fence 21 installed on the slope G has the configuration described in paragraph 0003, and the pair of columns 22 and 22 are made of H-shaped steel material having a length of about 1,500 mm on the lower end side. A snow stopper 24 is formed by fixing the fall prevention body 23 and horizontally arranging the cross beam members 24A, 24A, ... , The brace 25 is erected in an X shape, and the substrate 26 to which the support column 22 and the fall prevention member 23 are fixed is supported by the hanging type preventive fence support mechanism 27, so that the brace 25 is installed in a substantially vertical state on the slope G. be.

In the existing avalanche prevention fence 21 having the above configuration, after the fall prevention member 23 is removed, the lower three cross beam members 24A, 24A, 24A constituting the snow stopper 24 are removed from the fastener 24B. It is removed from the columns 22 and 22 and temporarily placed on the nearby slope G. Also, the brace 25 is removed from the support column 22. In this way, the pair of columns 22 and 22 is modified into the valley-side avalanche preventive body 2 of the embodiment in which the valley-side snow stopper 4 is provided on the upper side and the lower portion is the opening 5. A brace 9 is erected on a pair of valley-side columns 3 and 3 corresponding to the valley-side snow stopper 4.

Next, as shown in FIG. 4, the interval forming body 10 produced in advance is fastened and attached to the lower end side of each valley side column 3 with bolts and nuts, and the leg member 10D is welded to the substrate 11. By attaching the mountain side support 7 to the space forming body 10 in advance, the amount of work at the site can be reduced. After that, the three temporarily placed cross beam members 24A, 24A, and 24A are attached to the mountain side column 7 by the fastener 8B to form the mountain side snow stopper 8.
In this way, the valley-side snow stopper 4 is opposed to the opening 5 at a position 750 mm above the slope G with respect to the valley-side avalanche preventive body 2 having the valley-side snow stopper 4 on the upper side and the opening 5 on the lower side. By arranging the avalanche prevention body 6 on the mountain side, the installation of the avalanche prevention fence 1 according to the present embodiment is completed. Since the total load applied to the valley side avalanche preventive body 2 and the mountain side avalanche preventive body 6 does not change, the existing support mechanism 27 can be used as it is for the preventive fence support mechanism 12.
In this way, in the present embodiment, since the avalanche prevention fence 1 is configured by utilizing a part of the configuration of the existing avalanche prevention fence 21, the man-hours for the installation work on the slope G are reduced. Therefore, the construction period and installation cost can be reduced.

Next, the operation of the avalanche prevention fence 1 will be described in detail with reference to FIGS. 7 to 9. The valley-side avalanche preventive body 2 has an opening 5 on the lower side, and the snow on the front side (mountain side) of the avalanche preventive body 2 is configured to flow downward from the opening 5, so that the valley-side avalanche preventive body 2 and the slope The snow layer does not form high in the space area Y between G and the area Y between the left and right space forming bodies 10 and 10, and the snow layer S ₃ exceeds the valley side avalanche prevention body 2 and the cornice is formed. It does not reach the point of being formed. Further, since the amount of snow is small, the snow pressure applied to the snow layer in the space region Y from above due to subsidence is also small.
Then _, the snow pressure of the snow layer S4 sliding from above the slope G is supported by the mountain side avalanche preventive body ₆ to prevent the snow pressure from being applied to the snow layer S3 of the space region Y.

Further, a snow stop region Z having a substantially V-shaped vertical cross section is formed by the snow stop portion 8 of the mountain side avalanche prevention body 6 and the slope G, but the mountain side avalanche prevention body 6 is approximately half of the valley side avalanche prevention body 2. Since the height and area, the amount of snow accumulated in the snow stop area Z is half the amount of the snow stop area S of the existing avalanche prevention fence 21, so the snow density of the snow cover in the snow stop area Z does not increase so much. ..

Thus, in the present invention, the snow pressure due to the snow on the slope G and the snow pressure of the snow layer sliding down from above are shared by the valley-side avalanche preventive body 2 and the mountain-side avalanche preventive body 6, and the valley-side avalanche preventive body 2 Then, by letting the snow flow out from the opening 5, the phenomenon that the amount of snow is increased is eliminated, the formation of the cornice is suppressed, and the induction of an avalanche due to the fall of the cornice is prevented.

The principle of suppressing the formation of the cornice will be described with reference to FIGS. 8 and 9. As shown in FIG. 8, snow does not accumulate on the back side (valley side) of the preventive fence 1, but the front surface (mountain side) is blocked so that the amount of snow is twice the average amount of snow. However, since the valley-side avalanche preventive body 3 has approximately half the area of the preventive fence 21 in the prior art, the amount of snow accumulated in the average amount of snow L is also approximately half, and part of the snowfall from the opening 5 is. Since the outflow occurs, the amount of snow accumulated S3 by the valley-side avalanche preventive body ₂ is approximately half that of the conventional preventive body 21.

Further, the mountain side avalanche preventive body 6 and the slope G form a snow stop region Z having a substantially V-shaped vertical cross section, so that snow is deposited in this region Z. The mountain side avalanche preventive body 6 is a conventional preventive body 21. It consists of about half the height and area of the above, and by cooperating with the valley side avalanche preventive body 2, snow does not concentrate on any one of the preventive bodies 2 and 6, so there are two steps before and after. It forms a snow hill, and the snow does not reach a height exceeding the preventive bodies 2 and 6, and it is possible to prevent the formation of an avalanche.

The effect of suppressing the formation of cornice obtained in the experiment in which the anteroposterior length of the interval forming body 10 was set to 750 mm under the conditions of the avalanche prevention fence 1 having a fence height of 1,500 mm and a slope angle of 40 degrees was most remarkable. .. In addition, in an experiment using an interval forming body set to a front-back length of about 1,000 mm, it was confirmed that the front-back edges were cut off when the preventive bodies 2 and 6 were too far apart, and the synergistic phenomenon did not work effectively. rice field.

Further, in the present embodiment, a part of the existing avalanche prevention fence 21 is modified to form the avalanche prevention fence 1, but it goes without saying that the avalanche prevention fence 1 may be newly configured and installed. ..

Further, in the present embodiment, the valley-side avalanche prevention body 2 is composed of two pairs of valley-side columns 3, 3, but a valley-side column 3 may be added in the middle on the premise of this configuration.

Further, in the present embodiment, the valley side support 3 constituting the valley side avalanche prevention body 2 is erected on the substrate 11, and the substrate 11 is supported from above the slope by the prevention fence support mechanism 12, but the valley side. The support column 3 may be erected by burying the lower end side in the slope G.

1 Avalanche prevention fence 2 Valley side avalanche prevention body 3 Valley side support 4 Valley side snow stop 4A Cross beam 5 Opening 6 Mountain side avalanche prevention body 7 Mountain side support 8 Mountain side support 8A Cross beam G slope

Claims (4)

An avalanche prevention fence including a valley-side avalanche preventive body and a mountain-side avalanche preventive body, wherein the valley-side avalanche preventive body includes a pair of valley-side struts and a pair of valley-side columns that are erected laterally apart on a slope. The mountain-side avalanche preventive body is composed of a valley-side snow stopper formed by horizontally arranging a plurality of cross beam members on the upper side of the side column and an opening formed below the valley-side snow stopper. It is composed of a pair of mountain-side columns that are erected laterally apart on the slope and a mountain-side avalanche portion that is formed by horizontally arranging a plurality of cross beam members on the pair of mountain-side columns to prevent the mountain-side avalanche. The body is an avalanche prevention fence arranged so that the mountain-side snow stopper is opposed to the opening and is spaced above the slope with respect to the valley-side avalanche prevention body. The claim is characterized in that the mountain-side avalanche preventive body is arranged above the slope with an interval corresponding to a length of half the height of the valley-side support with respect to the valley-side avalanche preventive body. 1 Avalanche prevention fence described. The avalanche prevention fence according to claim 1, wherein the valley-side avalanche prevention body utilizes a part of the structure of the existing avalanche prevention fence already installed on the slope. A pair of valley-side struts are erected on the slope laterally apart, and a cross beam member is laid horizontally on the upper side of the pair of valley-side struts to form a valley-side avalanche, thereby forming the valley-side snow. A valley-side avalanche prevention body is installed on the lower side of the stop by an opening process, and a pair of mountain-side columns are erected at a position above the slope above the valley-side avalanche prevention body and laterally separated from each other. A mountain-side avalanche preventive body is installed by a step of horizontally arranging a plurality of cross beam members on the pair of mountain-side columns to form a mountain-side snow stopper, and the mountain-side snow stopper is opposed to the opening. A method of installing an avalanche prevention fence comprising a step of arranging a mountain-side avalanche preventive body at a distance above the slope with respect to the valley-side avalanche preventive body.

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