JP2018131806A - Slope protection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slope protection system in which netted bodies, pressure plates and anchors are used, and in which it is possible to increase a pressing area of the pressure plate without increasing the size of the pressure plate and to prevent damage to the netted body.SOLUTION: A slope protection system 10 has anchors 12 installed so that they are dispersed on a slope 102 of a natural ground, netted bodies 14 installed so as to extend on the slope 102, and pressure plates 16 that are mounted on the anchors 12 from above the netted bodies 14 and that press the netted bodies 14 to the slope side. The pressure plate 16 has at least three main skeleton parts extending by predetermined lengths in directions different from each other outwards in a plane direction from the center of the pressure plate 16, and a connection member that spans a space between the tips of the main skeleton parts so as to connect the tips. The connection member is inserted into a mesh of the netted body 14 in the space between the tips.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a slope protection system.

  Japan is an island country surrounded by the sea on all sides, and belongs to a climatic zone with heavy rainfall. Therefore, the slopes of natural rocks in Japan are prone to weathering of the surface layer due to repeated rain, and 1 to several meters of weathered unstable layer (surface layer) and the stable layer (deep layer) such as the bedrock underneath There is a feature that many are formed from.

  If the weathered unstable layer is left unattended, the slope collapses from this unstable layer, and gravel and rocks may fall downward, causing damage. The slope collapse from this unstable layer is mainly divided into two patterns. One is the phenomenon that the above surface layer (unstable layer) collapses along the boundary surface (slip surface) between the surface layer and deep layer of the natural ground, and the other is that the boundary surface is maintained. However, it is a local collapse phenomenon (so-called hollowing out) in which a part of the surface layer falls out of the surface layer. In addition, a slope collapse phenomenon in which surface slip and voids occur simultaneously may occur.

  Various methods have been proposed in the past to prevent surface slip and voids on the slopes of these natural grounds. For example, a tension member such as a ground anchor or a rock bolt is provided so as to penetrate from the surface layer to the stationary layer of the slope of the natural ground, and a planar cross-shaped or rectangular shape in plan view that can cover the slope widely at the end of the natural ground surface side of the tension member There has been proposed a slope protecting method in which a pressure receiving plate made of a heavy concrete block is attached, and a predetermined tension force is applied to the pressure receiving plate to lock the end of the tension member on the ground surface side and the pressure receiving plate.

  According to this slope protection method, by providing a plurality of pressure receiving plates so as to cover the entire slope, the entire slope is pressed down by the pressure receiving plate made of concrete block, and it suppresses slippage of the slope and surface omission. Can do.

  However, placing a heavy pressure block made of a concrete block on the entire slope leads to an increase in costs associated with the use of heavy machinery and a prolonged construction period, and the construction cost is high as a whole.

  Therefore, a technique for protecting slopes using a mesh body instead of a heavy concrete block has been developed. As shown in FIG. 8, the slope protection system using a net-like body includes anchors 112 installed on the slope 102 of the natural ground 100, a net-like body 114 spread on the slope 102, and a net-like body 114. And a pressure receiving plate 116 that is attached to the anchor 112 from above and presses the mesh body 114 toward the inclined surface 102 side. The slope 102 is protected by the pressure plate 116 and the entire mesh body 114 pressed to the slope 102 side by the pressure plate 116.

  As a pressure receiving plate used in such a slope protection system, there is a pressure plate that is not so heavy in weight for facilitating handling and installation work and can cover as many slopes as possible without hindering vegetation / greening of slopes. It is preferably used. Therefore, as the pressure receiving plate, a cross-shaped pressure receiving plate or a * -shaped pressure receiving plate that is not so large (for example, 50 cm to 1 m) is preferably used.

JP 2001-011863 A

  However, when the above-described cross-shaped pressure receiving plate is used, there is a situation in which the pressure applied to the inclined surface by the pressure receiving plate itself can be transmitted only to the inclined surface in contact with the cross-shaped pressure receiving plate. Therefore, it is desired to transmit the pressing force by the pressure receiving plate to a wider range of the slope as much as possible without increasing the size of the pressure receiving plate in terms of vegetation and weight. Further, since the mesh body and the inclined surface are pressed to the inclined surface side with a strong force by the cross-shaped pressure receiving plate, a load is generated in the portion of the mesh body that contacts the pressure receiving plate, and the mesh body may be damaged. If the mesh body is damaged, the slope stabilization effect by the mesh body may be reduced.

  Therefore, an object of the present invention is a slope protection system that uses a mesh body, a pressure receiving plate, and an anchor, and can increase the pressing area of the pressure receiving plate without increasing the size of the pressure receiving plate, and It is providing the slope protection system which can suppress damage.

  In order to achieve the above object, the slope protection system according to claim 1 is provided with anchors scattered on a slope of a natural ground, a mesh body extended on the slope, and an upper side of the mesh body. And a pressure receiving plate that is attached to the anchor and presses the mesh body toward the inclined surface, wherein the pressure receiving plate is predetermined in different directions outward from the center of the pressure receiving plate in the planar direction. And at least three main skeleton portions extending in length, and a connecting member that spans between the front end portions of the main skeleton portion and connects the front end portions, and the connecting member is disposed between the front end portions. It is inserted into the mesh of the mesh body.

  According to this configuration, the main part of the pressure receiving plate (which may be a cross-shaped pressure receiving plate, or a * -shaped or Y-shaped pressure receiving plate) having at least three main skeleton portions extending outward in the plane direction from the center. Since the pressure receiving plate and the mesh body are connected by a connecting member that spans the ends of the skeleton, the tensile force of the anchor is transmitted not only through the main skeleton of the pressure receiving plate but also through the connecting member. The As a result, since the area of the slope pressed by the pressure receiving plate is larger than that of the conventional one, it is possible to construct a more stable slope protection system. Further, since the pressing force by the pressure receiving plate is distributed not only to the pressure receiving plate itself but also to the connecting member, it is possible to alleviate the stress concentration at the contact portion between the main skeleton portion of the pressure receiving plate and the net-like body.

  The slope protection system according to claim 2 is characterized in that the connecting member is a wire rope. By using a wire rope that can follow the uneven shape of the slope to be installed, the effect of the present invention can be exhibited without being influenced by the uneven shape of the slope.

  The slope protection system according to claim 3. A hole is provided at the tip of the main skeleton, and the connecting member is bridged between the tips of the main skeleton by inserting the connecting member through the hole. And

  Thus, the pressure receiving plate and the net-like body are connected only by inserting the connecting member into the hole formed in the tip portion of the main skeleton, and the connecting member is not fixed to the pressure receiving plate and receives the pressure. Since the plate and the net-like body are connected, the connecting member can be installed so as to follow the uneven shape of the slope of the pressure receiving plate to be installed.

The slope protection system according to claim 4 is characterized in that the lines constituting the mesh have a thickness of 2 to 4 mm and a tensile strength of 800 to 2000 N / mm ² . By using a wire having such a thickness and high tensile strength as a wire constituting the net-like body, it is possible to obtain a slope protecting effect more powerfully and stably.

  According to the present invention, it is possible to provide a slope protection system that can increase the pressing area of the pressure receiving plate without increasing the size of the pressure receiving plate and can suppress damage to the mesh body. Therefore, by using the slope protection system of the present invention, not only can a stronger and more stable slope protection effect be obtained, but also vegetation and greening of the slope can be sufficiently promoted.

It is sectional drawing (a) and top view (b) which show an example of embodiment of the slope protection system of this invention. It is a perspective view which shows an example of the connection structure of a receiving plate and a net-like body. It is the top view (a) and sectional drawing (b) which show an example of a net-like body. It is a partial cross section figure of the pressure receiving plate which shows the other example of a hole. It is a fragmentary sectional view of the pressure receiving plate of the pressure receiving plate shown in FIG. It is a top view which shows the other example of a pressure receiving plate. It is a fragmentary perspective view which shows other embodiment of the slope protection system of this invention. It is the perspective view and whole figure which show the conventional slope protection system.

  Hereinafter, the present invention will be described in detail. Fig.1 (a) is sectional drawing (a) which shows embodiment of the slope protection system of this invention, FIG.1 (b) is the top view. FIG. 2 is a perspective view showing an example of a connecting structure of the pressure receiving plate and the net-like body. The natural ground 100 in which the slope protection system of the present invention is installed generally has a fault along a slope of a stabilized formation (deep layer) G1 such as a bedrock and a weathered unstable layer (surface layer) G2 on the deep layer G1. The thickness of the surface layer G2 of the natural ground 100 is generally 1 to 3 m. There is a slip surface S between the surface layer G2 and the deep layer G1, and the surface layer G2 collapses along the slip surface S, possibly causing damage to roads, railways, buildings, and the like in the collapse direction. The slope protection system of the present invention is installed on the slope 102 of such natural ground 100.

  The slope protection system 10 according to the present embodiment includes an anchor 12 that is scattered on the slope 102 of the natural ground 100, a mesh body 14 that is spread on the slope 102, and an anchor 12 from above the mesh body 14. And a pressure receiving plate 16 that presses the mesh body 14 toward the inclined surface 100 side. The basic effect is that the slope 102 is protected by the plurality of pressure receiving plates 16 arranged in a scattered manner and the mesh body 14 pressed to the side of the slope 102 by the plurality of pressure receiving plates 16.

  As shown in FIG. 2, the pressure receiving plate 16 is a pressure receiving plate (that is, a cross-shaped pressure receiving plate) having four main skeleton portions 18 extending outward from the center in the plane direction. A hole 19 for inserting the connecting member 20 is provided at the tip of 18. The connecting member 20 is composed of an annular wire rope, and the connecting member 20 is inserted into each hole 19 of each main skeleton 18. Further, the connecting member 20 is also inserted into the mesh of the mesh body 14 between the main skeleton portions 18. Thereby, the pressure receiving plate 16 and the mesh body 14 are connected via the connecting member 20.

  Since the pressure receiving plate 16 and the mesh body 14 are connected by the connecting member 20 in this way, the tensile force of the anchor 12 is transmitted not only through the pressure receiving plate 16 but also through the connecting member 20. As a result, the area to which the pressing force by the pressure receiving plate 16 is applied becomes wider than before, so that a more stable slope protection system can be constructed. Further, since the pressing force by the pressure receiving plate 16 is distributed not only to the pressure receiving plate 16 itself but also to the connecting member 20, stress concentration at the contact portion between the main skeleton 18 and the mesh body 14 of the pressure receiving plate 16 can be reduced. It becomes possible, and the deterioration of the mesh body 14 is suppressed.

  By using a wire rope as the connecting member 20, it is possible to follow the uneven shape of the slope to be installed, so that it is difficult to be influenced by the uneven shape of the slope, and the effect of the present invention is accurately exhibited. As the material of the wire rope as the connecting member 20, the same material (described later) as the wire used for the mesh body 14 can be used. The thickness of the wire rope is, for example, 6 to 15 mm. The connecting member 20 is preferably subjected to anticorrosion treatment. Examples of the anticorrosion treatment include zinc plating, zinc aluminum plating, resin coating, or a combination thereof. The ends of the connecting member 20 made of a single wire rope are fixed at the connecting portion 20a. Moreover, as the connection member 20, not only a wire rope but the rod-shaped member which consists of hard members, such as metal, may be sufficient. In this embodiment, only one wire rope is used. However, the present invention is not limited to this, and one connecting rope may be provided between each main skeleton portion, for a total of four connecting members. In this case, the main skeleton part and the connecting member are fixed at the front end part of the main skeleton part. As the connecting member, not only a wire rope but also a rod-shaped member may be used.

  As shown in FIG. 3A, the above-described net-like body 14 has a line 15 extending in the left-right direction as shown in the figure by a straight portion and a bent portion that are repeated at a predetermined interval, and the line 15 is It is a rhombus wire mesh having rhombus meshes 14a, which are connected to adjacent lines at a bent portion. The diameter of the inscribed circle when the inscribed circle of the mesh 14a of the mesh body 14 is drawn is preferably 5 to 15 cm, particularly preferably 5 to 10 cm. As shown in FIG. 3 (b), the mesh body 14 has a predetermined thickness I. The thickness is, for example, 10 to 30 mm.

The tensile strength of the lines 15 is preferably ^{800~2000N / mm 2, 1000~2000N / mm} 2 is particularly preferred. The diameter φ of the wire 15 is preferably in the range of 2 to 4 mm, particularly preferably 2.5 to 4 mm. By using a wire having such a thickness and high tensile strength, it becomes possible to obtain a slope protecting effect more powerfully and stably. The wire 15 is preferably made of hard steel, and specifically made of a hard steel wire defined in JIS G 3506. Since the hard steel wire has superior spring properties (elastic deformation) compared to the iron wire and is difficult to be plastically deformed, the inclined surface 102 can be pressed with a strong force.

  The net-like body 14 is not limited to this, and may be a conventionally used one. For example, a ring net obtained by connecting a large number of ring members made of a turtle shell metal mesh or an annular component wire so that the inner peripheral sides of adjacent ring members are in contact with each other can be used.

  As shown in FIG. 2, the pressure receiving plate 16 is a cross-shaped pressure receiving plate. Specifically, it has a rectangular parallelepiped center portion 17 and four main skeleton portions 18 extending outward from the center portion 17 in the planar direction. The angle of the extension direction of the adjacent main skeleton parts 18 is a right angle. The main skeleton 18 includes a bottom plate 18a and ribs 18b. The bottom plate 18 is made of a substantially rectangular plate member, and the rib 18b is configured to stand up from the end on the center portion 17 side to the tip of the bottom plate 18 at the center in the short direction of the bottom plate 18a. The rib 18b is configured such that the height thereof gradually increases from the front end portion of the main skeleton portion 18 toward the center side end portion. The corner portion of the tip of the main skeleton 18 of the bottom plate 18 is chamfered. The size of the pressure receiving plate 16 is usually such that the length between the tips of the adjacent main skeleton portions 18 is 0.5 to 1.5 m. The pressure receiving plate is made of iron or the like.

  A hole 19 for inserting the connecting member 20 is provided in the tip end region of the rib 18b. In the present embodiment, the hole 19 is formed in the vicinity of the tip of the rib 18b. However, the present invention is not limited to this. As shown in FIG. May be a hole.

  FIG. 5 is a cross-sectional view of the pressure receiving plate 16. A plurality of cylindrical projections 21 projecting downward are provided on the back surface 18ab of the bottom plate 18a of the main skeleton 18. The protrusion 21 is inserted into the mesh 14a of the mesh body 14 (see FIG. 3) and has a function of preventing the mesh body 14 from moving in the surface spreading direction. The length of the protrusion 21 may be a length that can be locked to the mesh body 14 and is, for example, in the range of 10 to 30 mm. The interval between the adjacent protrusions 21 can be adjusted according to the size of the mesh, for example, can be adjusted to an interval of one or two meshes.

  A cylindrical insertion hole 17a for inserting and fixing the anchor is formed in the center portion 17 in the vertical direction. The pressure receiving plate used in the present invention is not limited to those described above, and any pressure receiving plate may be used as long as it has at least three main skeleton parts extending in a different direction from the center to the outside in the plane direction. Good. 6A to 6C show examples of plan views of pressure receiving plates that can be used in the present invention. FIG. 6A is a pressure receiving plate having four main skeleton portions 38a to 38d, and the angle interval in the extending direction of each main skeleton portion 38a to 38d is 90 °. Of the four main skeleton portions 38a to 38d, the two opposite main skeleton portions 38b and 38d are formed shorter than the other two opposite main skeleton portions 38a and 38c. The pressure receiving plate may be a Y-shaped pressure receiving plate shown in FIG. 6B or a * -shaped pressure receiving plate shown in FIG. The illustrated pressure receiving plate may be formed with chamfered corners, and may further be provided with a reinforcing structure at a connection portion between the central portion and the main skeleton portion. The pressure receiving plate to be used is appropriately selected depending on the soil condition of the slope, the uneven shape, and the like. These pressure receiving plates also have a hole (not shown) at the tip of the main skeleton.

  The anchor 12 may be a conventionally used one, and a lock bolt is preferably used. The length of the anchor 12 is appropriately adjusted according to the state of the slope and the layer structure to which the slope protection system of the present invention is applied. The space | interval of the adjacent anchor 12 is 1.5-4m, for example, Preferably it is 2-3m. The arrangement of the anchors 12 may be a staggered arrangement as shown in FIG. 1 (b), or a rectangular strip arrangement that is aligned vertically and horizontally.

  Next, a procedure for constructing the slope protection system of the present invention will be described with reference to FIGS. First, the anchor 12 is first fixed to the slope 102. After the anchor 12 is inserted into the anchor hole 50 formed at a predetermined interval in the slope 102, cement milk 52 is injected into the anchor hole 50 to fix the anchor 12 to the slope 102. The head 12b of the anchor 12 is maintained in a state of being exposed to the ground surface.

  Next, the mesh body 14 is spread on the slope where the anchors 12 are scattered. The mesh body 14 is arranged such that a long diagonal line of two diagonal lines of the rhombus of the mesh body 14 coincides with or substantially coincides with the vertical direction.

  Next, the pressure receiving plate 16 is attached to the anchor 12 from above the mesh body 14. The pressure receiving plate 16 is attached to the anchor 12 by inserting the head portion 12b of the anchor 12 through the insertion hole 17a (see FIG. 2) of the center portion 17 of the pressure receiving plate 16. At this time, the pressure receiving plate 16 is attached so that the protrusion 21 of the pressure receiving plate 16 shown in FIG.

  Next, the connecting member 20 (see FIG. 2) is inserted through each hole 19 of the pressure receiving plate 16. During this insertion, the connecting member 20 is inserted into the mesh of the mesh body 14 between the main skeleton portions 18. It is preferable to insert several times in different meshes. Thereafter, both ends of the connecting member 20 are joined to make an endless shape. The pressure receiving plate 16 and the net-like body 14 are connected only by inserting the connecting member 20 into each hole 19. The connecting member 20 is not fixed to the pressure receiving plate 16, and the pressure-receiving plate 16 and the net-like body 14 are connected. Connected. Therefore, the connecting member 20 can be installed so as to follow the uneven shape of the slope 102.

  Thereafter, the pressure receiving plate 16 is pushed down together with the mesh body 14 in the inclined direction, and the cap nut 30 is screwed into the head 12b of the anchor 12 in a state where the mesh body 14 is pressed against the inclined surface. The attachment to the anchor 12 is completed. By pressing the pressure receiving plate 16 against the inclined surface 102, the portion of the inclined surface 102 where the pressure receiving plate 16 exists and the vicinity thereof are indented from the surroundings. Thus, the slope protection system of the present invention is completed.

  Next, another embodiment of the slope protection system of the present invention will be described with reference to FIG. In the drawing, the same components as those in the above-described embodiment are illustrated using the same reference numerals (see FIG. 2), and description thereof is omitted.

  What is characteristic in the present embodiment is that not only the vicinity of the tip 18c of the main skeleton 18 but also a hole 29 is formed between the tip 18c and the center portion 17 of the pressure receiving plate 16, and these holes That is, the second connecting member 30 is inserted into the portion 29. As the connecting member 30, the same member as the connecting member 20 can be used. The connecting member 30 is installed in the same manner as the connecting member 20, and is inserted into the mesh of the mesh body 14 between the main skeleton portions 18. Thus, the effect of the present invention described above can be further enhanced by further connecting the pressure receiving plate 16 and the mesh body 14 with the connecting member.

  The present invention is not limited to the configuration of the above embodiment, and various modifications are possible within the scope of the gist of the invention.

DESCRIPTION OF SYMBOLS 10 Slope protection system 12 Anchor 14 Net-like body 16 Pressure receiving plate 18 Main frame part 20 Connection member

Claims (4)

Anchors scattered on the slopes of natural ground, a mesh body extended on the slopes, and a pressure receiving plate that is attached to the anchors from above the mesh bodies and presses the mesh bodies to the slope side A slope protection system comprising:
The pressure receiving plate has at least three main skeleton parts extending a predetermined length in different directions from the center of the pressure receiving plate to the outside in the plane direction,
The slope protection system further includes a connecting member that is bridged between the distal end portions of the main skeleton portion and connects the distal end portions.
The connecting member is inserted into a mesh of the mesh body between the tip portions, and the slope protection system is characterized by.   The slope protection system according to claim 1, wherein the connecting member is a wire rope. A hole is provided at the tip of the main skeleton,
The slope protection system according to claim 2, wherein the connecting member is bridged between the distal end portions of the main skeleton portion by inserting the connecting member through the hole. The lines constituting the reticulated body, slope protection system according to claim 1 or 2, characterized in that it has a tensile strength of thickness and 800~2000N / mm ² of 2-4 mm.

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