JP5044227B2 - Rock fall prevention fence - Google Patents

Description

  The present invention relates to a rock fall prevention fence used to prevent the collapse of stones, rocks, surface soil, etc. generated on steep slopes on mountainsides, road construction, steep slopes created by land preparation, and the like.

  In civil engineering construction work in mountainous areas such as roads and railways, when a new slope is formed by cutting off the mountain side, there may be cases where rocks fall until the slope becomes stable. On steep slopes on the mountainside, stones, rocks, surface soil, etc. may collapse due to natural disasters such as earthquakes and heavy rains. In order to protect roads, railroads, private houses, etc. from such rockfalls, rockfall prevention fences have conventionally been installed on the boundary with slopes.

  As a rock fall prevention fence that has been frequently used in the past, for example, as shown in Patent Document 1, a fixed support is installed based on a support column, and a wire mesh previously stretched on a frame is hung on a support bracket on the support column. It attaches by.

  Conventionally, a method of catching falling rocks has also been proposed by forming a falling rock prevention fence in which H-shaped steel is horizontally mounted between the upright columns. FIG. 5 is a side view when the rock fall prevention fence 50 is provided at the boundary between the slope and the road. A plurality of support columns 51 whose lower portions are embedded in the foundation 53 are provided at appropriate intervals, and the H-shaped steel 52 is horizontally placed on the slope side of the support columns 51 at a predetermined interval. Incidentally, the H-shaped steel 52 is composed of a flange 52 a and a web 52 b, and one flange 52 a surface is disposed on the column 51.

  With respect to the rock fall prevention fence 50 having such a configuration, the rock fall 60 that collapses on the slope strikes the H-section steel 52 disposed on the slope side of the support column 51. As a result, the H-shaped steel 52 is impacted by falling rocks from obliquely above. The impact force causes the H-shaped steel 52 to be loaded with the load Fa in the horizontal direction and the load Fb in the vertically downward direction. From the structure of the H-section steel 52, it is a well-known fact that the proof stress in the horizontal direction to which the load Fa is applied is high and the proof strength in the vertical direction to which the load Fb is applied is low. That is, the horizontal direction in which the load Fa is applied is a so-called strong axis direction, and the vertical direction in which the load Fb is applied is a so-called weak axis direction. Therefore, when designing the rock fall prevention fence 50, the size, shape, etc. of the H-section steel are determined in consideration of whether the strength in the weak axis direction falls within the allowable proof strength.

  However, the rockfall prevention fence 50 having the configuration shown in FIG. 5 described above is configured to receive the impact of the rockfall due to the rigidity of the H-shaped steel 52 to the last. For this reason, in order to keep the strength in the weak axis direction within an allowable range even when a high impact due to a large rock fall is applied, the size of the H-section steel 52 must be increased. However, when the size of the H-section steel 52 is increased, the cost of the member becomes expensive, and the burden of construction labor increases due to the increase in weight accompanying the increase in the size of the H-section steel 52, which in turn increases the construction cost. There was a problem of end.

  For this reason, in recent years, instead of providing the H-shaped steel 52 in the horizontal direction, a rockfall prevention fence has been proposed in which fall energy absorbing protective members made of ultra-soft steel are fixed in multiple stages at intervals in the vertical direction ( For example, see Patent Document 2.) As a result, the fall energy absorption effect can be increased, and even if the panel is damaged by falling rocks, it is sufficient to replace only the panel at the damaged portion, so that the repair work period can be greatly reduced.

In addition, a method for buffering the impact itself caused by falling rocks has been proposed (see, for example, Patent Document 3). In the disclosed technique of Patent Document 3, a thinned material is introduced into a net fence so as to have a space that can be buffered and moved, and this is fixed to a rock fall protective wall made up of a column and a horizontal member.
Japanese Patent Publication No. 47-31562 JP 2005-61119 A Japanese Patent Laid-Open No. 2005-83068

  However, the technique disclosed in Patent Document 2 assumes that the panel is deformed to some extent by falling rocks, and expects a reduction in the repair period by improving the ease of replacement of the deformed panel. . However, when the panel due to falling rocks deforms, the appearance as a fence also deteriorates. Moreover, if the fallen rock is generated again before the deformed panel is replaced, it may not be possible to reliably receive the fallen stone, which may significantly impair safety.

  Further, in the disclosed technique of Patent Document 3, the emphasis is placed on the technical improvement of the buffer material for buffering the impact of falling rocks. However, with respect to the rock fall prevention wall itself that supports this cushioning material, it has been known for a long time that the rock fall is firmly received unless the resistance to impact is increased, and in particular, the H shape without increasing the size of the H section steel. It was necessary to preferentially solve the improvement in the yield strength of the steel in the weak axis direction.

  Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is a rockfall that can improve the yield strength against rockfall without increasing the size of the shape steel. It is to provide a prevention fence.

  In order to solve the above-mentioned problems, the present inventor erected a plurality of support pillars whose lower part is embedded in the foundation at appropriate intervals, and horizontally laid the shape steel in a substantially horizontal direction between the support pillars. A rockfall prevention fence was invented in which at least one reinforcing member was disposed between the columns so as to intersect the shape steel in a substantially vertical direction, and the bottom surface of the reinforcing member was not fixed and was in contact with the foundation.

In addition, the rock fall prevention fence according to claim 1 of the present invention includes a plurality of struts, the lower portion of which is embedded in the foundation, at a suitable interval, and a steel bar extending in a substantially horizontal direction between the struts. In a rock fall prevention fence that is horizontally mounted and further has a shock absorbing material for absorbing rock fall energy attached to at least the shape steel, at least one reinforcing member is substantially perpendicular to the shape steel between the columns. The base spacing material is disposed between the reinforcing member and the foundation, and the bottom surface of the reinforcing member is not fixed and is in contact with the base spacing material.

In the invention according to claim 2 , the height of the basic spacing material can be adjusted up and down.

  In the present invention, since the stress transmitted in the weak axis direction can be dispersed, the yield strength against falling rocks can be improved without increasing the size of the shape steel. That is, according to the present invention, the size of the shape steel can be reduced, so that the workability can be improved and the construction cost can be reduced.

  Moreover, in this invention, what is necessary is just to fix in the state mounted on the surface, without embedding a reinforcement member in a foundation, and it also becomes possible to reduce construction labor. By adopting a configuration in which this reinforcing member is not embedded in the foundation, if there is a large falling rock and the reinforcing member is deformed, it can be easily replaced with another reinforcing member. In addition, by adopting a configuration in which this reinforcing member is not embedded in the foundation, it is possible to install this reinforcing member after the construction of the rock fall prevention fence is completed. Furthermore, since this reinforcing member can be easily installed by not being embedded in the foundation, it can be added at any location between the columns as needed, and the entire fence can be reinforced. It becomes.

  Furthermore, in the present invention, since a large stress in the weak axis direction generated based on the impact caused by falling rocks is transmitted vertically downward by the reinforcing member and can be dispersed by reacting with the foundation, a greater impact Even when is added, it is possible to absorb such an impact without deforming the shape steel. That is, in the present invention that can suppress the deformation of the shape steel, it is not necessary to perform the replacement work as in the prior art, and it is possible to receive the falling rock more reliably, and it is possible to further improve the safety. .

  Hereinafter, as a best mode for carrying out the present invention, a rockfall prevention fence used for preventing rockfall will be described in detail with reference to the drawings.

  1A, 1B, and 1C are configuration diagrams of a rockfall prevention fence 1 to which the present invention is applied. The rock fall prevention fence 1 is disposed to prevent the fall rock falling from the mountain side from falling to the valley side. Incidentally, FIG. 1 (a) is a front view seen from the valley side, FIG. 1 (b) is a plan view when the falling rock prevention fence 1 is viewed from above, and FIG. 1 (c). FIG. Incidentally, in FIG. 1 (b), the upper side is the mountain side through the rockfall prevention fence 1, and the lower side is the valley side through the rockfall prevention fence 1. Further, in FIG. 1 (c), the left side is a mountain side through a rockfall prevention fence 1, and the right side is a valley side through the rockfall prevention fence 1.

  The fall prevention fence 1 is a fence having a basic skeleton composed of a support column 2 erected over a plurality at appropriate intervals, and a shape steel 3 horizontally mounted between the support columns 2. In addition, the fall prevention fence 1 is arranged such that the reinforcing member 12 intersects the section steel 3 in a substantially vertical direction.

  The support column 2 is a shape steel whose lower end 2a is embedded and fixed to an existing foundation 11 made of concrete. The support column 2 is erected in a substantially vertical direction from the existing foundation 11. In the following description, the case where the support columns 2 are erected at regular intervals will be described as an example.

  The section steel 3 is disposed on the surface of the support 2 on the mountain side. As the shape steel 3, any shape steel such as angle steel, groove steel, I-shape steel, T-shape steel, H-shape steel, Z-shape steel, etc. may be used. In the following description, a case where an H-section steel is used as the section steel 3 will be described as an example. The shape steel 3 is constructed over a plurality of stages at intervals in the vertical direction.

  As shown in the front view shown in FIG. 2A and the plan view shown in FIG. 2B, the reinforcing member 12 has a structure in which a base plate 15 is fixed to the bottom end portion of the angle steel 14.

  Since the reinforcing member 12 having such a configuration is composed of a substantially L-shaped angle steel 14, any one side surface of the angle steel 14 can be brought into contact with the shape steel 3 and attached thereto. It becomes. In the fall prevention fence 1 to which the present invention is applied, as shown in FIG. 1 (b), the angle steel 14 in the reinforcing member 12 is attached to the flange surface on the mountain side in the shape steel 3 to fix them.

  In the fall prevention fence 1, the shock absorbing material 5 for further absorbing the energy of falling rocks may be attached to the shape steel 3 at least. This buffer material 5 is provided to buffer the impact itself due to falling rocks. For example, the thinned material may be attached to the shape steel 3, or a plurality of thinned materials bound with iron wires. It may be attached to the shape steel 3. Incidentally, as the buffer material 5, for example, a unit of a buffer material for civil engineering and building structure disclosed in Patent Document 3 may be applied.

  Moreover, in this fall prevention fence 1, you may make it install the mount frame 19 on the upper surface of the foundation 11, for example. The gantry 19 supports the bottom surface of the cushioning material 5 by floating from the ground over a predetermined height so that rainwater and moisture do not penetrate into the lower end of the cushioning material 5 and corrode.

  Next, the construction method of the rock fall prevention fence 1 to which the present invention is applied will be described.

  First, the columns 2 are embedded in the foundation 11 at regular intervals. As a result, the lower end 2a of the column 2 is in a state of being completely fixed in the foundation 11. Next, the shape steel 3 is erected sequentially with respect to the upright column 2. You may make it perform attachment to the support | pillar 2 of this shape steel 3 via a volt | bolt and a nut. In such a case, for example, as shown in the enlarged front view of the rock fall prevention fence 1 as viewed from the mountain side in FIG. 3, two holes for inserting bolts are provided in the middle of the vertically extending column 2. Further, two holes are formed in the flange end portion of the shape steel 3 two by two. And the hole drilled in the edge part of the structural steel 3 is put in the hole of the support | pillar 2, and this is fastened with the volt | bolt 21 and it fixes. As a result, both ends of the shaped steel 3 are in a state of being attached and fixed to the support column 2 respectively.

  Next, the reinforcing member 12 is attached. When the reinforcing member 12 is attached, holes are formed in advance in two substantially vertical directions on the flange surface on the mountain side of the structural steel 3 and the reinforcing member 12, and bolts 22 are attached to these at the time of attachment. And may be fixed by tightening with a nut. As a result, the reinforcing member 12 is firmly fixed on the flange surface on the mountain side of the structural steel 3.

  In addition, when attaching this reinforcement member 12, it adjusts so that the bottom face of the baseplate 15 fixed to the lower end may be in the state contacted on the foundation 11. FIG. At this time, the bottom surface of the base plate 15 is not fixed to the base 11 and is in contact with the base 11 in an unfixed state. That is, the bottom surface of the base plate 15 may be placed on the foundation 11.

  Finally, the buffer material 5 is attached to the shape steel 3 and installed on the mount 19 to complete the construction.

  In the rock fall prevention fence 1 constructed in this way, for example, as shown in FIG. 4, the rock fall 66 that collapses the slope from the mountain side is first obliquely above the structural steel 3 installed in the horizontal direction. It will be hit from. As a result, the shape steel 3 is subjected to an impact due to falling rocks obliquely from above. With this impact force, the shape steel 3 is loaded with the load Fa in the horizontal direction and the load Fb in the vertical downward direction. In the case where the section steel 3 is configured as an H-section steel, the proof stress in the horizontal direction to which the load Fa is applied is high, and the proof stress in the vertical direction to which the load Fb is applied is low. That is, the horizontal direction in which the load Fa is applied is a so-called strong axis direction, and the vertical direction in which the load Fb is applied is a so-called weak axis direction.

  For this reason, when an impact force due to falling rocks is applied to the structural steel 3, a vertically downward force is transmitted to the reinforcing member 12 disposed so as to intersect the structural steel 3 in a substantially vertical direction. Become. In particular, since the vertically downward direction is the weak axis direction, a larger stress is transmitted to the vertically downward direction (arrow direction in the figure) through the reinforcing member 12. The stress transmitted through the reinforcing member 12 to the base plate 15 causes a reaction at the contact surface between the bottom surface of the base plate 15 and the foundation 1, and as a result, the stress is distributed through the foundation 1.

  As described above, in the present invention, since the stress transmitted in the weak axis direction can be dispersed, the yield strength against falling rocks can be improved without increasing the size of the shape steel 3. That is, in the present invention, the size of the shape steel 3 can be reduced, so that the workability can be improved and the construction cost can also be reduced.

  Moreover, in this invention, what is necessary is just to fix in the state made to mount on the surface, without embedding the reinforcement member 12 in the foundation 11, and also it becomes possible to reduce construction labor.

  Furthermore, in the present invention, it is possible to disperse the large stress in the weak axis direction generated based on the impact caused by the falling rocks by causing the reinforcing member 12 to transmit the stress downward vertically and reacting with the foundation 11, so that Even when a large impact is applied, the impact can be absorbed without deforming the structural steel 3. That is, in the present invention that can suppress the deformation of the shape steel 3, it is not necessary to perform the replacement work as in the prior art, and it is possible to receive the falling rock more reliably, and the safety can be further improved. Become.

  Further, even when the reinforcing member 12 itself is deformed by falling rocks, the lower end 2a of the reinforcing member 12 is not fixed to the base 11, so that the replacement work can be performed more easily. In addition, the reinforcing member 12 that can be easily attached can be disposed at an arbitrary position later.

  Depending on the foundation, when the auxiliary member 12 is long, the auxiliary member 12 may be inserted by making a hole in the foundation 11. In that case, you may make it put a non-shrink mortar in the opened hole.

  The columns 2 adjacent to each other are arranged so that the interval is 2 m. At this time, the reinforcing member 12 is disposed in the middle of the adjacent struts 2. That is, it is assumed that the reinforcing member 12 is disposed at an interval of about 1 m with respect to the closest column 2. As a result, the reinforcing member 12 can transmit the force in the weak axis direction downward based on the above-described mechanism and disperse the force, so that the function as the support column 2 can be performed. For this reason, it becomes possible to maintain the yield strength with respect to falling rocks of the falling rock prevention fence 1 whole by reducing the number of the support | pillars 2 and arrange | positioning the reinforcement member 12 in the middle.

  Since it is easier to dispose the reinforcing member 12 than to dispose the support column 2, it is possible to reduce construction labor by providing the reinforcing member 12 as an alternative to the support column 2. It becomes possible to improve the degree of freedom of the design itself.

  Note that the present invention is not limited to the case where one reinforcing member 12 is provided in the middle of the columns 2 arranged at intervals of 2 m, and two or more reinforcing members 12 may be provided. . Further, the reinforcing member 12 is not limited to the case where the reinforcing member 12 is disposed in the middle of the column 2, and may be disposed at any position between the columns 2. Further, the interval between the support columns 2 is not limited to 2 m, and it is needless to say that any interval may be used.

  The present invention is based on the premise that the bottom surface of the base plate 15 of the reinforcing member 12 is not fixed and is brought into contact with the foundation 11, but is not limited thereto. For example, irregularities are formed on the surface of the foundation 11, and the base plate 15 of the reinforcing member 12 set in advance to a predetermined length may not contact the surface of the foundation 11. For this reason, as shown in FIG. 6 (a), the lower end of the reinforcing member 12 is installed so as to be lifted from the base 11, and the base spacing member is inserted between the reinforcing member 12 and the base plate 15, and the periphery of the base spacing member is inserted. May be filled with non-shrink mortar 32. Incidentally, the non-shrink mortar 32 is applied only for preventing the metal fitting 31 from being displaced and preventing rust. As the basic spacing member 33, a square pipe may be used as shown in FIG. 6A, or an iron plate or various shaped steels may be used if the spacing is narrow.

  Thereby, even if unevenness is formed on the surface of the base body 11, the base plate 15 at the lower end of the reinforcing member 12 can be reliably brought into contact with each other via the basic spacing member, and the force transmitted vertically downward can be obtained. This can be dispersed by reacting with the metal fitting 31 via the base plate 15.

  FIG. 6B shows an example in which a base spacing member 33 is provided as an alternative to the metal fitting 31. The non-shrink mortar 32 for embedding the basic spacing member 33 is configured to cover the upper part of the base plate 15, but is not limited thereto. Further, even if the non-shrinkable mortar 32 covers the upper part of the base plate 15, the base plate 15 and the base spacing member 33 are configured to be not fixed to each other.

  The base spacing member 33 may have a height adjustment function. FIG. 7A shows an example of the basic spacing member 33 having a height adjusting function. The basic spacing member 33 shown in FIG. 7A includes a lower plate 34, an upper plate 35, a nut 36, and a screw portion 37.

  The screw part 37 is composed of a rod-like body on which a male screw is formed. The lower end of the screw portion 37 is fixed to the lower plate 34. The nut 36 is formed with a female screw and is fixed to the upper plate 35. By screwing the nut 36 with the upper plate 35 into the threaded portion 37 and rotating it, the height of the upper plate 35 can be adjusted up and down.

  Further, the basic spacing member 33 is not formed separately from the reinforcing member 12, but the basic spacing member 33 may be integrated with the lower portion of the reinforcing member 12 as shown in FIG. 7B, for example. Good. In such a case, the configuration of the base plate 15 to be disposed under the reinforcing member 12 is omitted, and the upper plate 35 is provided in the lower portion, and these are integrated. At this time, as shown in FIG. 7B, a nut 36 may be provided on the upper surface of the upper plate 35 so as to be positioned inside the reinforcing member 12. Further, a force applied to the upper plate 36 may be received by providing the nut 36 on the lower surface side of the upper plate 35. Thereby, the appearance can be improved by making the nut 36 invisible from the outside. In such a configuration, of course, the height may be adjusted by rotating the lower plate 34 to which the screw portion 37 is attached.

It is a block diagram of the rock fall prevention fence to which this invention is applied. It is a block diagram of the reinforcement member to which the base plate was fixed in the bottom end part. It is a front enlarged view of the rock fall prevention fence 1 seen from the mountain side. It is a figure for demonstrating the effect of this invention. It is a figure for demonstrating the problem of a prior art. It is a figure which shows the example which inserts a metal fitting between a reinforcement member and a baseplate. It is a figure which shows the example which comprised the base space | interval material so that height adjustment was possible.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Falling rock prevention fence 2 Support | pillar 3 Shape steel 5 Buffer material 11 Existing foundation 12 Reinforcement member 14 Yamagata steel 15 Base plate 19 Mount 31 Metal fitting 32 Non-shrink mortar 33 Base spacing material 34 Lower plate 35 Upper plate 36 Nut 37 Screw part 66 Falling stone

Claims (2)

In order to absorb the energy of falling rocks, the pillars with the lower part embedded in the foundation are erected over a plurality of appropriate intervals at the same time. In the rock fall prevention fence where the cushioning material is attached to at least the above shape steel,
Between the struts, at least one reinforcing member is disposed so as to intersect in a substantially vertical direction with respect to the shape steel,
A base spacing material is installed between the reinforcing member and the foundation,
A rock fall prevention fence, wherein the reinforcing member has a bottom surface that is not fixed and is in contact with the foundation spacing member. The rock fall prevention fence according to claim 1 , wherein the foundation spacing member is vertically adjustable.

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