JP2018100484A - Rockfall protection fence - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easily-set-up rockfall protection fence which enables reduction in displacement amount of a rock catching net from its originally set up position, with the reduced number of parts, reduced weight, and reduced cost.SOLUTION: A plurality of support pillars 10 are set with predefined intervals in a transverse direction of a slope S in front view. A net 14 is set up among the support pillars 10 so as to be supported by the plurality of support pillars. Transfer members 2 whose stiffness is bigger than that of the net 14 and whose shape is longer vertically are set immediately or adjacently to the net 14 at a region between the support pillars 10. The transfer members 2 are fastened with a wire material of the net 14 and fastening materials 4 together with a horizontally reinforcing rope 26. With the forementioned arrangement, the deformed region of the net 14 catching falling rock stretches vertically, and the maximum deformation amount and displacement amount of the net 14 become smaller. Fastening lower ends of the transfer members 2 to a concrete structure 12 by a connecting rope 6 prevents gaps in catching falling rock.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rock fall protection fence, and more particularly, to a rock fall protection fence that can be installed on a road, for example.

  Conventionally, in order to reduce damage caused by falling rocks, falling rock protection fences have been widely installed on mountain slopes (including slopes). There are various forms of such rockfall protection fences. Among them, a plurality of columns are erected on the slope, and the net body is stretched between the columns by supporting the net body with these columns. There is something set. This kind of rock fall protection fence is intended to reduce the damage by taking advantage of the deformability of the net body and capturing the rock fall with the deformation of the net body. In other words, when falling rocks come into contact with the net body, the net body itself deforms to disperse the impact, and the maximum time required for the deformation of the net body is reduced, thereby absorbing the kinetic energy of the falling rock. it can.

  As a rock fall protection fence that stretches such a net body between columns, for example, there is one described in Patent Document 1 below. In the rockfall guard fence described in Patent Document 1, a ring-type net is used as a net body, and an auxiliary rope is provided between the upper side position and the lower side position of the net body in a support column on which the net body is stretched. A buffer that allows the extension rope to stretch between both ends when the load is applied by falling rocks when the load is applied by falling rocks. Means were provided. For this reason, for example, prior to absorption of rock fall kinetic energy due to deformation of the ring net, when the fall rock comes into contact with the net body and a load is applied, the buffer means eases the impact with the extension of the total length of the auxiliary rope. Kinetic energy is absorbed efficiently.

JP 2014-1584 A

  By the way, when a rock fall protection fence using this type of net body is installed on the road, for example, the size of the net body that has captured the rock fall protrudes in the direction below or below the slope. It is necessary not to be too much. In other words, this is to reduce the amount of displacement from the original tension position (hereinafter also referred to as the setting tension position) of the net body that has captured the falling rock. On the other hand, the net body used for this type of rockfall protection fence only captures rockfall by deforming only the portion in contact with the rockfall, in other words, trapping rockfall with local deformation. Since it is impossible to predict where the falling rock will collide with the net body, as described above, in order to reduce the amount of displacement from the set tension position of the net body that captured the falling rock, the net body rigidity is eventually stretched. It needs to be increased over the entire range. However, in general, a net body having a large overall rigidity has a large disadvantage such as being expensive or heavy. In addition, as another countermeasure, for example, narrowing the interval in the lateral direction of the inclined surfaces of the columns may be disadvantageous, but doing so has disadvantages such as an increase in the number of members and a large construction.

  The present invention has been made in view of the above problems, and its purpose is to enable the reduction of the number of parts, weight, and cost, and the construction of the net body that captures falling rocks while being easy to construct. An object of the present invention is to provide a rock fall protection fence that can suppress the amount of displacement from the position.

  In order to achieve the above-mentioned object, the rockfall protection fence according to claim 1 is supported by a plurality of struts erected on the slope with a predetermined interval in the left-right direction in front view of the slope, and the plurality of struts. In the falling rock guard fence provided with the net body stretched between the pillars, it is arranged to extend in the vertical direction so as to be in contact with or close to the net body in the region between the pillars. A transmission member having rigidity higher than at least the net body is provided.

  According to this configuration, since the transmission member having rigidity higher than that of the net body and extending vertically is provided in contact with or close to the net body in the region between the columns, the net member stretched between the columns is attached to the net body. The deformation area of the net body when a falling rock collides expands in the vertical direction. Therefore, the maximum deformation amount of the net body can be reduced, and the displacement amount of the net body from which the falling rock is captured from the set tension position can be suppressed. As a result, it is not necessary to use a large rigid net body, and the weight and cost can be reduced accordingly. In addition, since it is not necessary to reduce the lateral distance between the slopes of the pillars that support the net body, the number of pillars can be reduced, and the number of parts and costs can be reduced accordingly. Will also be easier. Further, if the deformation of the transmission member can be avoided by expanding the deformation area of the net body and capturing the falling rock, the transmission member can be reused after the falling rock is captured.

  The rockfall protection fence according to claim 2 is the rockfall protection fence according to claim 1, wherein the transmission member has substantially the same length as the vertical length of the net body to be stretched. .

  According to this configuration, since the deformation area of the net body when the falling rock collides is expanded in the entire vertical direction, the maximum deformation amount of the net body can be further reduced, and the net body that has caught the falling rock can be set and stretched. The amount of displacement from the position can be further suppressed.

  The rock fall protection fence according to claim 3 is the rock fall protection fence according to claim 1 or 2, wherein the transmission member is arranged on the slope mountain side with respect to the net body.

  According to this configuration, the deformation region of the net body when the rock falls collides can be expanded as quickly as possible, and as a result, the maximum amount of deformation of the net body can be further reduced. It is possible to further suppress the amount of displacement from the set stretching position of the net body that has captured.

  The rockfall protection fence according to claim 4 is the rockfall protection fence according to any one of claims 1 to 3, wherein a lower end portion of the transmission member is a concrete structure or a foundation structure fixed to the slope. It is connected with a connecting rope.

  According to this configuration, it is possible to suppress the lower end portion of the transmission member from being separated from the inclined surface when the falling rock collides, so that the falling rock can be reliably captured by the net body. In addition, the maximum amount of deformation of the net body can be further reduced, and the amount of displacement of the net body from which the falling rock is captured from the set tension position can be further suppressed.

  The rock fall protection fence according to claim 5 is the rock fall protection fence according to claim 4, wherein the length of the connection rope is accompanied by a predetermined braking force when a load of a predetermined value or more is applied to the connection rope. A brake device is provided that allows the stretch to be extended.

  According to this configuration, since the braking force acts on the extension of the connecting rope by installing the brake device, the kinetic energy of the falling rock is adjusted according to the deformation of the net body by the braking force when the falling rope collides and the connecting rope extends. It can be absorbed.

  The rockfall protection fence according to claim 6 is the rockfall protection fence according to any one of claims 1 to 5, wherein the upper portions of the adjacent struts are close to each other between the upper portions of the adjacent struts. A lateral member to be regulated is arranged.

  According to this configuration, since the proximity between the upper portions of adjacent struts on both sides of the slope in the lateral direction of the portion where the falling rock collides with the net body is regulated by the lateral member, unnecessary slack of the net body is suppressed, and as a result In addition, it is possible to suppress the amount of displacement from the set tension position of the net body that has captured the falling rock.

  The rockfall protection fence according to claim 7 is the rockfall protection fence according to any one of claims 1 to 6, wherein the net body is spanned between the pillars at least at both ends in the lateral direction of the slope. A lateral reinforcement rope that is fixed and reinforces the net body is inserted or connected.

  According to this configuration, it is possible to widen the deformation area of the net body when a falling rock collides, also in the lateral direction of the slope (lateral direction), thereby further reducing the maximum deformation amount of the net body. In addition, it is possible to further suppress the amount of displacement from the set stretching position of the net body that has captured the falling rock.

  In addition, by adjusting the trapping of rock fall by the net body and the deformation suppression of the net body by the lateral reinforcement rope, the kinetic energy of the rock fall by the lateral reinforcement rope before the net body deforms and absorbs the kinetic energy of the rock fall It becomes possible to receive.

  As described above, according to the present invention, the deformation area of the net body when the falling rock collides with the net body expands in the vertical direction, so that the maximum deformation amount of the net body can be reduced and the falling rock is captured. The amount of displacement of the net body from the set tension position can be suppressed. As a result, it is not necessary to use a net with high rigidity, and the weight and cost can be reduced accordingly. In addition, since it is not necessary to reduce the lateral distance between the slopes of the pillars that support the net body, the number of pillars can be reduced, and the number of parts and costs can be reduced accordingly. Will also be easier. Moreover, if the deformation | transformation of a transmission member can be avoided by catching a falling rock by utilizing the deformability of a net body, it will also become possible to reuse a transmission member after a falling rock capture.

It is the partial partial whole front view which looked at one embodiment of the rock fall protection fence of the present invention from the slope trough side. It is a partial cross section side view of the rock fall protection fence of FIG. It is a front view of a net body from the rhombus metal mesh used for the rock fall protection fence of FIG. It is a front view which shows an example of the brake device used for the rock fall protection fence of FIG. It is a perspective view which shows the other example of the brake device used for the rock fall protection fence of FIG. It is explanatory drawing of an effect | action of the rock fall protection fence of FIG. It is explanatory drawing which shows the state by which the falling rock was capture | acquired by the falling rock protection fence of FIG. 6 (A). It is explanatory drawing which shows the state by which the falling rock was captured by the falling rock protection fence of FIG. It is explanatory drawing which shows the state by which the falling rock was capture | acquired by the falling rock protection fence from which the horizontal member was removed from FIG. 6 (A). It is a front view of the ring type net | network which can be used as a net body of FIG.

  Hereinafter, embodiments of the rock fall protection fence of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial cross-sectional front view of the rockfall protection fence of this embodiment as viewed from the sloped valley side, and FIG. 2 is a partial cross-sectional side view thereof. The rock fall protection fence according to this embodiment is the same as the existing rock fall protection fence, in order to prevent damage from falling rocks on the slope (including the slope) S, as viewed from the front of the slope (lateral direction). ). In this embodiment, a foundation-like concrete structure 12 that is continuous in the lateral direction of the slope at a constant height is formed as the foundation of a rockfall protection fence. The concrete structure 12 is constructed, for example, by placing concrete around a housing (not shown).

  From the upper surface of the concrete structure 12, a plurality of (four in the figure) support columns 10 are erected at predetermined intervals set in advance in the lateral direction of the slope. The rock fall protection fence according to this embodiment tries to prevent damage by supporting the net body 14 with the pillars 10 while stretching the net body 14 between the pillars 10 and capturing the rocks with the net body 14. Is. The falling rocks are not only those that roll down along the slope S, but also those that fall away from the slope S while floating. Since the fallen rocks are also captured by the net body 14, the pillar 10 that supports the net body 14 also needs to have a certain height. Also, it is impossible to predict where rockfall will occur in the lateral direction of the slope. Therefore, the height of the support columns 10 is, for example, 2 m to 5 m, and the interval between the support columns 10 is, for example, 3 m to 5 m, and in some cases about 10 m, and these are appropriately selected according to the scale and situation of the slope S. As this support | pillar 10, what has comparatively large rigidity, such as a steel square pipe, is used, for example. As this support | pillar 10, what filled concrete inside the square pipe made from steel, for example can also be used. Further, the strut 10 may be a resin or metal hollow pipe filled with rubber.

  For example, as shown in Patent Document 1 described above, the support column 10 may be provided with a tiltable structure such as a hinge at the lower end portion of the support column 10 so that, for example, the support column 10 tilts toward the inclined valley side. It is. In that case, it is necessary to support the upper part of the column 10 with a rope or the like. However, in this embodiment, the displacement amount (deformation amount) of the net body 14 from the position before the net body 14 captures the falling rock (set extension position), specifically, the net body 14 that has captured the falling rock. Since the main purpose is to make the projection dimension in the direction of projecting below the slope or in the direction projecting from the slope S as small as possible, it is desirable that the column 10 does not tilt to the slope valley side. In addition, when installing a collapsible structure in the support | pillar 10, it installs the brake device which generate | occur | produces braking force at the time of inclination of a support | pillar, and absorbs the kinetic energy of a falling rock with the braking force at the time of inclination of a support | pillar. It is desirable.

  For the net body 14 of this embodiment, for example, a rhombus wire net 22 made of a metal wire having a rhombus mesh as shown in FIG. 3 is used. For example, as described in Japanese Patent Application Laid-Open No. 2016-37773, the rhombus wire mesh 22 is formed by bending a metal wire 24 to form a triangular wave wire, and crests and valleys of a plurality of triangular wave wires arranged in parallel. It is configured by knitting each other and engaging their triangular wave wires. Mild steel, hard steel, spring steel, stainless steel, or the like can be used for the metal wire 24 constituting the triangular wave wire. The metal wire 24 may be subjected to a coating treatment if necessary, thereby preventing wear or corrosion of the contact portion of the triangular wave wire. Examples of the coating treatment include galvanizing treatment and polyester coating treatment.

In this embodiment, since it is important to reduce the maximum deformation amount of the net body 14, it is desirable that the metal wire 24 constituting the net body 14 made of the rhombus metal mesh 22 also has a small deformation amount and a relatively high mechanical strength. . Accordingly, a particularly preferable metal wire 24 is a hard steel wire (single wire), particularly a wire made from a hard steel wire defined in JIS G 3506, for example, a hard steel wire (JIS G 3521). Galvanized steel wire (JIS G 3548). Tensile strength of the wire, for example 800~2500N / mm ^2, preferably advantageously from 1000~2000N / mm ^2, in particular 1500~2000N / mm ^2.

  By using such a hard steel wire, the net body 14 having a large rigidity and a small weight can be obtained. It is also preferable to use a hard steel wire that is excellent in elastic deformability as the metal wire 24. The thickness of this type of single wire metal wire 24 is, for example, 2 to 10 mm, and preferably 2.6 to 4 mm. The wire used for the net body of the conventional rockfall protection fence is a mild steel wire, that is, an iron wire, and it is plastically deformed relatively easily. Accordingly, the energy absorption amount of the net body of the mild steel wire is small, and the auxiliary rope (the lateral reinforcing rope 26 in this embodiment) disposed on the sloped valley side of the net body is mainly a falling rock as in the prior art described above. Absorbs kinetic energy. Naturally, the maximum deformation of the net body of the conventional mild steel wire rod is large. On the other hand, since the net body 14 comprised of a hard steel wire as in this embodiment is lightweight and has high rigidity, the amount of energy absorbed by the deformation of the net body 14 is large. Therefore, the kinetic energy of falling rocks can be greatly absorbed by the deformation of the net body 14 made of hard steel wire. As a result, the net body 14 made of a hard steel wire rod has a small maximum deformation amount at the time of falling rock capture and a small displacement amount from the set tension position.

Further, the metal wire 24 may be a stranded wire formed by twisting a plurality of strands, as described in, for example, Japanese Patent Application Laid-Open No. 2014-66054. What is preferable as a stranded wire is a stranded wire (6 to 25 mm in diameter) produced by twisting a plurality (for example, 2 to 5) of strands (for example, 2 to 5 mm in diameter). As the strand, one having a tensile strength of 400 to 2000 N / mm ² , preferably 800 to 2000 N / mm ² is used. As such a strand, the hard steel wire mentioned above can be used, for example. By using the stranded wire, the metal wire 24 can be bent without damaging the wire itself when it is bent into a triangular wave shape. In addition, it is preferable that the wire has been subjected to anticorrosion treatment. The anticorrosion treatment can be performed, for example, by coating with zinc plating, aluminum zinc alloy plating or resin (polypropylene, polyethylene, polyvinyl chloride) or the like.

  The size of the rhombus mesh of the rhombus wire mesh 22 constituting the net body 14 is such that the radius of the inscribed circle of the rhombus is about 4.5 to 8.5 cm as described in, for example, JP-A-2013-19198. It is comprised by the magnitude | size which becomes the range of. By configuring the mesh in such a size, it is possible to configure a sufficiently large mesh while preventing falling rocks from passing through the mesh of the net body 14, so that the deformability of the net body 14 is appropriate. And the absorption of kinetic energy of falling rocks by the net body 14 is further promoted. The size of the mesh is obtained, for example, by setting the shorter diagonal line of the formed rhombus to 10 to 20 cm, the longer diagonal line to 20 to 30 cm, and the smaller interior angle to 50 ° to 70 °. . In this way, by making the mesh not a square (or regular polygon) but a rhombus, the radius of the inscribed circle can be made small even if the length of one side of the mesh is the same. It is possible to capture without leakage. Moreover, in this embodiment, the net body 14 is installed so that the extending direction of the longer diagonal line of the formed rhombus is the vertical direction (vertical direction). Thereby, if it is the net body 14 which formed the rhombus mesh of the same shape, since the tensile strength of the vertical direction can be made the strongest, the falling rock falling to the slope valley side can be received more effectively. it can.

  Note that the mesh shape of the net body 14 is not limited to a rhombus, but may be a polygon as appropriate. Further, as described later, for example, a ring-type net described in Patent Document 1 can be used for the net body 14. Further, it is desirable that the lower end portion of the net body 14 is as close as possible to the concrete structure 12, that is, the slope, and the gap between the two is made as small as possible.

  In this embodiment, as clearly shown in FIG. 1, a lateral member 16 is disposed between the upper ends of adjacent struts 10, and this lateral member 16 acts as a so-called tension bar so that both struts 10 are close to each other. To regulate. In this embodiment, the end portion of the lateral member 16 and the upper end portion of the support column 10 are firmly connected by a connection structure (not shown). The horizontal member 16 restricts the columns 10 that are pulled downward by the net body 14 from approaching each other when falling rocks are captured by the net body 14 as described later. Thereby, the unnecessary bending | deflection of the net body 14 can be suppressed, As a result, the displacement amount from the setting tension position of the net body 14 which caught the fallen rock can be made small. Therefore, at least the same rigidity as that of the support column 10 is given to the lateral member 16.

  Further, in this embodiment, for example, as in the above-mentioned Patent Document 1, a horizontal reinforcing rope 26 is bridged and fixed at least between the pillars 10 at both ends in the lateral direction of the slope among the plurality of pillars 10. The lateral reinforcement rope 26 is inserted or connected to the net body 14, thereby reinforcing the net body 14. The lateral reinforcing rope 26 supports the falling rock indirectly by supporting the net body 14 that has captured the falling rock, and also absorbs the kinetic energy of the falling rock. The right end of FIG. 1 of the lateral reinforcing rope 26 is firmly fixed to the column 10 at the right end of the figure via a locking tool 28, and the left end of FIG. It is fixed to a support 10 at the left end in the figure through 30. For example, a high-strength wire rope is applied to the lateral reinforcing rope 26. The wire diameter of the lateral reinforcing rope 26 is, for example, about 12 to 30 mm.

  In this embodiment, a plurality (six in this embodiment) of lateral reinforcing ropes 26 are stretched with a space in the vertical direction. In this embodiment, the uppermost lateral reinforcement rope 26-1 is disposed on the upper side of the net body 14, and the lowermost lateral reinforcement rope 26-6 is disposed on the lower side. These lateral reinforcing ropes 26 are inserted so as to sew a mesh of a rhombus wire mesh that constitutes the net body 14, and are firmly fastened by a fastening member 4 together with a transmission member 2 described later. The lateral reinforcing rope 26 may be disposed on the slope valley side of the net body 14. Further, the number of the horizontal reinforcing ropes 26 is not limited to the above, but the horizontal reinforcing ropes 26 are arranged at least on the lower side of the net surface of the net body 14, preferably on the upper side and the lower side. It is desirable to install. Further, the horizontal reinforcing rope 26 may not be bridged in the horizontal direction.

  The actual lateral reinforcing rope 26 is slightly slackened due to its own weight or the weight of the net body 14. The kinetic energy absorption effect of falling rocks by the net body 14 is exhibited when the net body 14 is deformed. On the other hand, since the falling rocks are captured by the net body 14 and the net body 14 bulges to the slope valley side, the slack of the rope disappears and the lateral reinforcing rope 26 is tensioned. The net body 14 that has captured the falling rocks can be supported. At this time, if a braking force is applied to the elongation of the lateral reinforcement rope 26 while allowing the elongation, the kinetic energy of the falling rocks can be absorbed by the elongation of the lateral reinforcement rope 26 accompanied by the braking force. For this reason, a brake device 30 is provided at the left end of the lateral reinforcing rope 26 in the drawing with a predetermined braking force to allow extension of the length between the two fixed portions of the rope.

  FIG. 4 shows an example of a brake device 30 that applies a braking force while allowing the rope to stretch. This figure is a front view of the brake device 30 of FIG. 1 as viewed from the slope mountain side. The brake device 30 is configured by winding a metal strip 52 having a width in a direction perpendicular to the paper surface around a solid cylindrical member 54, and is short from one end of the metal strip 52 in the longitudinal direction, in this case, the cylindrical member 54. One end of the lateral reinforcing rope 26 is connected to the other end. Further, a stopper 58 is provided at the other end of the metal band 52, and two buffering protrusions 60 projecting in pairs on both surfaces of the metal band 52 are provided in front of the stopper 58. Is provided. Further, in this brake device 30, a holding member 56 that holds the metal band 52 relatively tightly is attached to the outside of the metal band 52 that is wound around the cylindrical member 54. It fixes to the slope mountain side surface of the support | pillar 10 of the illustration left end part side of FIG.

  In this brake device 30, when the tension is applied to the lateral reinforcing rope 26 and is pulled in the direction of the arrow in the figure, the metal strip 52 is also pulled in the same direction. At this time, the metal strip 52 has to pass through a narrow passage formed by the column member 54 and the holding member 56, and at this time, a portion wound around the column member 54 moves. At the portion where the metal band 52 is wound around the cylindrical member 54, plastic deformation continuously occurs as the wound portion moves. Since the continuous plastic deformation accompanying the movement of the winding portion of the metal band 52 around the cylindrical member 54 is deformation resistance, the length between both fixed portions of the lateral reinforcing rope 26 is extended against the deformation resistance. At this time, a braking action, that is, a braking force is generated, and the kinetic energy of falling rocks acting on the lateral reinforcing rope 26 is greatly absorbed. Note that the amount of extension of the lateral reinforcing rope 26 is regulated by the position of the stopper 58.

  FIG. 5 is a perspective view showing another example of the brake device 30. The brake device 30 includes a loop pipe 32 and a fastening member, and a midway portion of the lateral reinforcing rope 26 is inserted into the loop pipe 32. Both ends of the loop tube 32 are overlapped in parallel, and this overlapped portion is clamped by a fastening member, for example, a compression sleeve 34, and the overlapped portion of the loop tube 32 is mutually fixed by the compression sleeve 34. The loop tube 32 and the compression sleeve 34 are in frictional contact with each other. The loop tube 32 is preferably a steel tube, but may be made of other metal materials or plastic materials.

  In this brake device 30, when a large tension is generated in the lateral reinforcing rope 26, a force is applied to reduce the diameter of the loop tube 32, and both ends of the loop tube 32 apply forces in opposite directions along the rope. receive. When the tension applied to the rope exceeds the frictional force between the loop tubes 32 and between the loop tube 32 and the compression sleeve 34 at the location where the compression sleeve 34 is tightened, slippage occurs between them against the frictional resistance. Due to this slip, the kinetic energy of the falling rock is absorbed while extending between the two fixed portions of the lateral reinforcing rope 26. At that time, the kinetic energy is also absorbed by the deformation of the loop tube 32. By selecting the diameter, wall thickness, and material of the loop tube 32, the energy absorption capability can be variously changed, and various requirements can be met. In addition, although the case where the loop pipe | tube 32 is 1 turn is shown in the figure, double winding or more winding numbers may be sufficient.

  In FIG. 1, one brake device 30 is provided for one lateral reinforcement rope 26, but a plurality of brake devices 30 may be provided for one lateral reinforcement rope 26. And when providing the several brake device 30 with respect to the one horizontal direction reinforcement rope 26, you may set the magnitude | size of the braking force of those brake devices 30 to a mutually different magnitude | size. As described above, the braking force of the brake device 30 depends on the tension of the lateral reinforcing rope 26. With such a braking force distribution, for example, when two brake devices 30 are provided in one lateral reinforcing rope 26, the tension of the lateral reinforcing rope 26 that supports the net body 14 that has captured the falling rocks is increased. Accordingly, one of the brake devices 30 operates first to exhibit braking force, and thereafter, the other brake device 30 operates to exhibit braking force. By doing so, it is possible to continuously or intermittently exert braking force, that is, continue to absorb kinetic energy, while the lateral reinforcing rope 26 that supports the rock fall continues to grow.

  In this embodiment, the transmission member 2 that is long (extends) in the vertical direction (longitudinal direction) is disposed so as to be in contact with or close to the net body 14 in the region between the columns 10. The transmission member 2 is made of, for example, a steel plate or bar, and has at least higher rigidity than the net body 14. Further, the transmission member 2 is desirably less rigid than the column 10. For example, the transmission member 2 has a rigidity of 1/10 to 1/3, preferably 1/6 to 1/4 of the rigidity of the column 10. . Here, as is well known, the rigidity is represented by, for example, a product value of Young's modulus E and cross-sectional secondary moment I. In this embodiment, the rigidity to be evaluated is the rigidity in the direction displaced by the falling rock, that is, the direction perpendicular to the surface of the net body 14. The rigidity of the transmission member 2 in the direction perpendicular to the surface of the net body 14 is set to 1/10 to 1/3, preferably 1/6 to 1/4, of the rigidity of the column 10.

  In this embodiment, a total of three transmission members 2 are arranged between the columns 10 with a predetermined interval, one in the middle of the columns 10 and one on each side in the lateral direction. . These transmission members 2 are arranged on the slope mountain side with respect to the net body 14. In this embodiment, the length of the transmission member 2 is the same as the length of the net body 14 in the vertical direction (longitudinal direction). Therefore, the transmission member 2 has the entire length in the vertical direction from the upper side to the lower side of the net body 14. To touch. In other words, the upper end portion of the transmission member 2 abuts on the uppermost lateral reinforcing rope 26-1 located on the upper side of the net body 14, and the lower end portion of the transmission member 2 is the lowermost lateral portion located on the lower side of the net body 14. It abuts on the direction reinforcing rope 26-6. In this embodiment, at the position where the transmission member 2 and the lateral reinforcing rope 26 intersect, they are fastened together with the wire of the net body 14 by the fastening member 4.

  Furthermore, in this embodiment, the lower end portion of the transmission member 2 is connected to the concrete structure 12. Since the concrete structure 12 is fixed to the slope S, it can be said that the lower end portion of the transmission member 2 is connected to the slope S. Instead of the concrete structure 12, the lower end portion of the transmission member 2 may be connected to the foundation structure of the rock fall protection fence fixed to the slope S. The lower end portion of the transmission member 2 is connected to the concrete structure 12 via a connecting rope 6. Specifically, the upper end portion of the connecting rope 6 is directly fixed to the lower end portion of the transmission member 2, and the lower end portion of the connecting rope 6 is fixed to the anchor 8 embedded in the concrete structure 12. As will be described later, the connecting rope 6 is not necessarily required if there is not enough clearance between the bottom end of the net body 14 and the slope (including the concrete structure 12) to allow rock fall. In the drawing, the connecting rope 6 is slack, that is, no allowance is provided, but the connecting rope 6 may be provided with allowance, specifically, slack. This margin may be set to about 1/5 to 1/10 of the distance between the columns 10, for example.

  The connecting rope 6 has a length of the connecting rope 6 itself with a predetermined braking force when a load of a predetermined value or more is applied to the connecting rope 6, that is, when the tension becomes a predetermined value or more. A brake device 30 that allows elongation is provided. As shown in FIG. 2, the brake device of FIG. 5 described above is used for the brake device 30. The brake device 30 may be the brake device shown in FIG. Therefore, like the brake device 30 used for the lateral reinforcement rope 26, when the length between the two fixed portions of the connecting rope 6 is extended, a braking action, that is, a braking force is generated, and the falling rocks acting on the connecting rope 6 are generated. Kinetic energy is greatly absorbed. When slack (margin) is given to the connecting rope 6, as will be described later, the transmission member 2 is displaced as the falling rock is captured by the net body 14, so that the connecting rope 6 is not slackened and the connecting rope 6 is lost. When a predetermined tension is applied, a braking force is generated by the brake device 30.

  FIG. 6 is a longitudinal sectional view schematically showing the operation of the rock fall protection fence of this embodiment. In either case, only the uppermost and lowermost lateral reinforcement ropes 26 are shown, and the other lateral reinforcement ropes are not shown. FIG. 6A shows a rockfall protection fence in which the transmission member 2 and the connecting rope 6 are not provided, and a net body 14 such as a rhombus metal mesh is stretched between the columns 10. The net body 14 is deformed by the collision of the falling rock R. As shown in FIG. 6A, in the rock fall protection fence without the transmission member 2, the net body 14 is locally deformed only in the contact portion of the rock fall R in the direction below the slope or projecting from the slope S. As shown in FIG. 6A, when the net body 14 is locally deformed only at the contact portion of the falling rock R to absorb the kinetic energy of the falling rock R, the maximum deformation amount of the net body 14 is large. Moreover, the local deformation | transformation of the net body 14 by rock fall capture | acquisition is so small that it is close to the support | pillar 10, and conversely, the farther from the support | pillar 10, ie, the middle of the support | pillar 10 and the support | pillar 10 is the largest. When the maximum deformation amount of the net body 14 is large, the projecting dimension in the direction of projecting from the slope S or the slope S of the net body 14 that has captured the falling rock R, that is, the displacement amount from the set tension position increases. For example, when the rock fall protection fence is close to a person's house or road, if the amount of displacement from the set extension position of the net body 14 that has captured the rock fall R is large, the rock fall protection fence may not function sufficiently.

  7A and 7B schematically illustrate a state in which the falling rock R is captured by the falling rock protection fence in which the transmission member 2 and the connecting rope 6 are removed from the falling rock protection fence in FIGS. 7A is a plan view, and FIG. 7B is a front view of a slope. Only a part of the net body 14 is illustrated.

  7 shows that the net body 14 is locally deformed from the stretch of the lateral reinforcing rope 26 shown in FIG. 7, that is, the bent state of the rope shown in the figure. As a result, the local maximum deformation amount of the net body 14 Is understood to be large. A large amount of maximum deformation of the net body 14 means that the amount of displacement from the set tension position of the net body 14 that has captured the falling rock R is large. However, in this example, since the horizontal member 16 is disposed in the same manner as the rock fall protection fence of FIGS. 1 and 2, as will be described later, the net body that has captured the rock fall as compared to the case without the horizontal member. The amount of displacement from the set tension position of 14 is suppressed.

  FIG. 8 is an explanatory view schematically showing a state where the falling rock R is captured by the falling rock protection fence from which the lateral member 16 is further removed from the falling rock protection fence of FIG. 7, and FIG. 8 (A) is a plan view, FIG. 8 (B) is a front view of a slope. Only a part of the net body 14 is illustrated. When the falling rock R collides with the net body 14, the struts 10 on both sides in the lateral direction of the colliding portion are pulled in the direction below the inclined surface or projecting from the inclined surface by the net body 14 that has captured the falling rock R. The upper parts of the columns 10 try to be close to each other. In FIG. 8, since there is no lateral member that regulates this, each support column 10 is deformed so that the upper portions of the adjacent support columns 10 on both sides of the falling rock colliding portion are close to each other, and each support column 10 is lowered below the slope along with the deformation. I am inclined. If the support column 10 supporting the net body 14 is deformed or tilted in this way, the net body 14 will not be stretched. The displacement amount of the captured net body 14 from the set tension position is further increased. Note that the tilted state of the column 10 in FIG. 8 is exaggerated for easy understanding, and the actual tilt of the column 10 is much smaller.

  On the other hand, in the rock fall protection fence of FIG. 7 in which the transverse member 16 is disposed between the adjacent struts 10, the upper portions of the struts 10 when the net body 14 captures the fall rock R are restricted from approaching each other. The As a result, unnecessary slack of the net body 14 is suppressed, and the amount of displacement of the net body 14 that has captured the falling rock R from the set tension position can be suppressed by that amount. However, further suppression of this amount of displacement is expected.

  FIG. 6B schematically shows a state where the falling rock R is captured by the falling rock protection fence in which the transmission member 2 of FIGS. 1 and 2 is arranged on the falling rock protection fence of FIG. 6A. The falling rock protection fence, for example, needs to capture the falling rock R falling in a state where it floats away from the slope S with the net body 14, and therefore extends from the slope S to a certain height and is stretched over. However, the falling rock R substantially contacts the lower part of the net body 14 in most cases. Therefore, when the transmission member 2 that is long in the vertical direction and has higher rigidity than the net body 14 is disposed between the strut 10 and the strut 10 in contact with or close to the net body 14, for example, a falling rock may fall into the net body. When it collides with the lower part of 14, the kinetic energy of the falling rock R is also transmitted to the upper part of the net body 14 via the transmission member 2, and the net body 14 is also deformed at the transmitted part. That is, by disposing the transmission member 2 that is long in the vertical direction along the net body 14, the deformation region of the net body 14 extends in the vertical direction, and the kinetic energy of the falling rock R is absorbed more efficiently. As a result, the maximum deformation amount of the net body 14 is reduced, and the displacement amount of the net body 14 that has captured the falling rock R from the set tension position is suppressed.

  Furthermore, in this embodiment, since the length of the transmission member 2 is the same as the length of the net body 14 in the vertical direction, the deformation area of the net body 14 at the time of a rockfall collision can be widened in the entire vertical direction. The kinetic energy of R is absorbed more efficiently. Therefore, the maximum deformation amount of the net body 14 can be further reduced, and the displacement amount of the net body 14 that has captured the falling rock R from the set tension position can be further reduced. Further, since the rigidity of the transmission member 2 is larger than that of the net body 14 and smaller than that of the column 10, the transmission member 2 is deformed after the net body 14 is deformed and before the column 10 is deformed. The kinetic energy of the falling rock R can also be absorbed by deformation.

  By the way, when the transmission member 2 that is long in the vertical direction is disposed along the net body 14, the deformation area of the net body 14 is expanded upward at the time of falling rock collision, and accordingly, the entire net body 14 is pulled upward. As a result of the net body 14 being pulled upward, the net body 14 and the slope S. In this embodiment, if there is a gap between the net body 14 and the concrete structure 12, the net body 14 is temporarily The trapped rock R may fall again from the gap. Further, the maximum deformation amount of the net body 14 that has captured the falling rock R is likely to be increased by the amount that the net body 14 is pulled upward, and accordingly, the displacement amount from the set tension position is also likely to increase.

  As shown in FIG. 1 and FIG. 2, the rockfall protection fence of this embodiment has the lower end of the transmission member 2 connected to the concrete structure 12 by the connecting rope 6, so that the rockfall R is captured by the net body 14. However, as shown in FIG. 6C, the net body 14 is not easily pulled upward. Therefore, in the rockfall protection fence of this embodiment, even if the rockfall R collides, a gap is not formed between the net body 14 and the slope S (including the concrete structure 12), and the captured rockfall R is again from the gap. It is possible to avoid falling. At the same time, the maximum deformation amount of the net body 14 that has captured the falling rock R can be reduced, and the displacement amount from the set tension position can also be reduced.

  FIG. 9 is an explanatory view schematically showing a state in which the falling rock R is captured by the falling rock protection fence of the embodiment shown in FIGS. 1 and 2, that is, FIG. 9 (A) is a view of FIG. 6 (C). FIG. 9B is a plan view of the slope of FIG. 6C. Only a part of the net body 14 is illustrated. As is clear from the figure, in the rockfall protection fence according to this embodiment, the net body 14 that has captured the rockfall R is set from the stretched position, specifically, from the portal type formed by the column 10 and the lateral member 16. The amount of displacement is significantly smaller than those in FIGS. Therefore, for example, installation on the roadside becomes possible. In addition, if there is not enough space for rock fall to pass between the net body 14 capturing the rock fall and the slope S, in this embodiment, the concrete structure 12, the lower end of the transmission member 2 is connected to the slope. There is no need. Even in such a case, it is desirable that the gap between the net body 14 and the slope S, in this embodiment, the concrete structure portion 12 be as small as possible.

  As the net body 14 described above, a ring net described in Patent Document 1 described above can also be used. For example, as shown in FIG. 10, the ring-type net 18 is configured so that four ring-shaped members 20 are evenly arranged around one ring-shaped member 20, and the inner peripheral side of the ring-shaped members 20. Connect so that they are in contact with each other. The connection structure of the ring-shaped member 20 has various forms.

  The ring-shaped member 20 is configured by winding a wire made of, for example, a steel wire a plurality of times (5 to 20 times) and tightening several places in the circumferential direction with a fastener. The fastener is, for example, a substantially cylindrical fitting having a C-shaped side surface, and is fixed by crimping after covering the outer side of the wire polymerized by winding. For example, the ring-shaped member 20 adjusts the strength and energy absorbing power at the time of deformation described later by adjusting the material of the wire, the wire diameter of the wire, the number of windings of the wire, the caulking force by the fastener, and the like. Can do.

The wire constituting the ring-shaped member 20 is preferably, for example, a steel wire manufactured from a hard steel wire, but may be an iron wire manufactured from a mild steel wire, for example. In the case of a steel wire, one having a tensile strength of 800 N / mm ² or more is preferable. Also, those obtained by plating or coating these wires can be used. More preferably, the ring-shaped member 20 is comprised with the hard steel wire used for the rhombus metal mesh mentioned above. The wire diameter of the wire is about 2.5 to 5 mm, and the diameter of the ring-shaped member 20 is set according to the size of the falling rock to be captured. The ring type net | network 18 can respond | correspond easily to the magnitude | size of the falling rock of the capture | acquisition object by changing the diameter of the ring-shaped member 20. FIG. For example, if the size of the rocks and gravel on the slope S is investigated and the diameter of the ring-shaped member 20 is set in accordance with the size, the falling rocks when the falling rocks are generated can be captured effectively.

  For example, when a force (load) perpendicular to the net surface is applied to the ring-type net 18 configured by connecting the ring-shaped members 20, the ring-shaped members 20 are pulled together, so that the shape of the ring-shaped member 20 itself is deformed. At the same time, the wire material constituting the ring-shaped member 20 is deformed so as to be loosened. These deformations occur when kinetic energy of rock falls, specifically, when the rocks collide and a load is applied to the net surface. When a load is applied to the ring net 18, the ring-shaped member 20 is deformed, and the rock falls. Kinetic energy is absorbed, and as a result, the ring-type net 18 captures the falling rock.

  Accordingly, the force necessary for the deformation of the ring-shaped member 20, in other words, the kinetic energy of the falling rocks that can be absorbed by the deformation of the ring-shaped member 20 is, for example, the material, the wire diameter, the number of turns of the wire constituting the ring-shaped member 20, Or it can adjust with the caulking force of the wire by a fastener.

  As described above, according to the rockfall protection fence of this embodiment, the plurality of support columns 10 are provided upright with a predetermined interval in the front view left and right direction of the slope S, and are supported by the plurality of support columns 10. Is stretched between the support columns 10, the transmission member 2 having a rigidity higher than that of the net body 14 and being long in the vertical direction is disposed so as to contact or be close to the net body 14 in the region between the support columns 10. To do. Thereby, the deformation | transformation area | region of the net body 14 when a falling rock collides with the net body 14 stretched between the support | pillars 10 spreads up and down. Accordingly, the maximum deformation amount of the net body 14 can be reduced, and the displacement amount of the net body 14 that has captured the falling rock from the set tension position can be suppressed. As a result, it is not necessary to use the net body 14 having a large rigidity, and the weight and cost can be reduced accordingly. In addition, since it is not necessary to reduce the distance in the lateral direction of the slope of the support column 10 that supports the net body 14, the number of support columns 10 can be reduced, and the number of parts and the cost can be reduced accordingly. And construction becomes easy. Moreover, if the deformation | transformation of the transmission member 2 can be avoided by expanding the deformation | transformation area | region of the net body 14 and catching a falling rock, it will also become possible to reuse the transmission member 2 after a falling rock capture.

  Moreover, by making the rigidity of the transmission member 2 smaller than that of the support column 10, the transmission member 2 is deformed before the support column 10 is deformed after the net body 14 captures the falling rock. Accordingly, the kinetic energy of the falling rock is absorbed not only by the deformation of the net body 14 but also by the deformation of the transmission member 2, so that the kinetic energy of the falling rock can be efficiently absorbed. Further, if the deformation of the support column 10 can be avoided, the support column 10 can be reused after the falling rock is captured.

  In addition, since the length of the transmission member 2 is the same as the length of the net body 14 in the vertical direction, the deformation area of the net body 14 when the falling rock collides widens in the entire vertical direction. Can be further reduced, and the amount of displacement of the net body 14 that has captured the falling rock from the set tension position can be further suppressed.

  Moreover, by arranging the transmission member 2 on the slope mountain side with respect to the net body 14, the deformation area of the net body 14 when a falling rock collides can be expanded in the vertical direction as quickly as possible. The maximum deformation amount of the body 14 can be further reduced, and the displacement amount of the net body 14 that has captured the falling rock from the set tension position can be further suppressed.

  Moreover, since the lower end part of the transmission member 2 is connected to the concrete structure 12 or the foundation structure, it is possible to suppress the lower end part of the transmission member 2 from being separated from the slope S when a falling rock collides. The falling rock can be reliably captured by the net body 14. Moreover, the maximum deformation amount of the net body 14 can be further reduced, and the displacement amount of the net body 14 that has captured the falling rock from the set tension position can be further suppressed.

  Further, the lower end of the transmission member 2 is connected by a connecting rope 6, and the connecting rope 6 is allowed to extend the length of the connecting rope 6 with a predetermined braking force when a load exceeding a predetermined value is applied. A brake device is provided. As a result, the braking force acts on the extension of the connecting rope by installing the brake device, and therefore the kinetic energy of the falling rock is absorbed in accordance with the deformation of the net body 14 by the braking force when the falling rope collides and the connecting rope 6 extends. It becomes possible to do.

  Further, by arranging the lateral member 16 that restricts the upper portions of the adjacent struts 10 from being close to each other between the upper portions of the adjacent struts 10, the adjacent struts 10 when the falling rock comes into contact with the net body 14. Since the proximity between the upper parts of the net body 14 is regulated by the lateral member 16, unnecessary slackening of the net body 14 is suppressed, and as a result, the displacement amount of the net body 14 that has captured the falling rock from the set stretch position is suppressed. Can do.

  In addition, a lateral reinforcing rope 26 that is bridged between the columns 10 at both ends of the slope in the left-right direction and fixed and reinforces the net body 14 is inserted into or connected to the net body 14. Thereby, it becomes possible to expand the deformation area of the net body 14 when the falling rock collides, also in the lateral direction of the slope (lateral direction), the maximum deformation amount of the net body 14 can be further reduced, and the falling rock is captured. The amount of displacement of the net body 14 from the set tension position can be further suppressed.

  Further, by adjusting the trapping of the falling rock by the net body 14 and the deformation suppression of the net body 14 by the lateral reinforcement rope 26, the lateral reinforcement rope 26 before the net body 14 is deformed and absorbs the kinetic energy of the falling rock. It will be possible to receive the kinetic energy of falling rocks.

  As mentioned above, although embodiment was described, the structure of this invention is not limited to these embodiment, A various deformation | transformation is possible within the range of the summary of invention. For example, the number and materials of the lateral reinforcing rope 26 and the transmission member 2 described above are appropriately selected according to the situation at the site, and those brake devices are not limited to the above-described configuration. Any one may be used as long as it allows the extension of the lateral reinforcing rope 26 and the connecting rope 6 with a braking force.

  Further, in the above-described embodiment, the net body 14 is stretched between the struts 10 at both ends in the lateral direction of the slope only by one stretch, but for example, the net body 14 may be stretched between the struts 10.

  In addition, the present invention can be applied not only to newly constructing on the slope S, but also to install the column 10 and the net body 14 with the structure of the present invention on the foundation of the existing rock fall protection fence.

2 Transmission member 6 Connecting rope 10 Support column 12 Concrete structure 14 Net body 16 Horizontal member 18 Ring type net (net body)
22 Diamond wire mesh (net body)
26 Lateral reinforcement rope 30 Brake device S Slope

Claims (7)

A plurality of pillars erected on the slope with a predetermined interval in the left-right direction in front view of the slope;
In a rock fall protection fence provided with a net body stretched between the columns by being supported by the plurality of columns,
Falling rock protection comprising a transmission member arranged to extend in the vertical direction so as to be in contact with or close to the net body in an area between the columns, and having at least a rigidity greater than that of the net body fence.   The falling rock guard according to claim 1, wherein the transmission member has a length that is substantially the same as a length of the stretched net body in the vertical direction.   The rock fall protection fence according to claim 1, wherein the transmission member is disposed on the slope mountain side with respect to the net body.   The falling rock protection fence according to any one of claims 1 to 3, wherein a lower end portion of the transmission member is connected to a concrete structure or a foundation structure fixed to the slope with a connection rope. .   5. The brake device according to claim 4, wherein the connecting rope is provided with a brake device that allows a length of the connecting rope to be extended while a predetermined braking force is applied when a load of a predetermined value or more is applied. Rock fall protection fence.   The rock fall protection fence according to any one of claims 1 to 5, wherein a lateral member that restricts the upper portions of the adjacent struts from approaching each other is disposed between the upper portions of the adjacent struts. In the net body,
7. The horizontal reinforcing rope that is bridged and fixed between the pillars at least at both ends in the left-right direction of the slope, and is inserted or connected to a lateral reinforcing rope that reinforces the net body. The rock fall protection fence described in 1.

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