JP2024057370A - Slope stabilization structure - Google Patents

Abstract

To provide a slope stabilization structure with measures to prevent slope erosion caused by deer feeding damage, which can prevent slope collapse such as landslides and a reduction in bearing pressure of a bearing plate due to deer feeding damage.SOLUTION: A slope stabilization structure 1 installed on a slope G1 to stabilize the slope comprises: a plurality of rock bolts 2 fixed in the ground on the slope G1 at predetermined intervals D1; a plurality of nuts 3 screwed into the lock bolt 2; and a bearing plate 4 attached to the rock bolt 2 with a nut 3 to bear the ground and preventing collapse of the slope G1. A bracket material 5 is interposed between the bearing plate 4 and the nut 3, a net 6 is stretched over the bracket material 5 to prevent deer from entering, and a tensioning height of the net 6 is maintained at a predetermined distance from the slope G1.SELECTED DRAWING: Figure 2

Description

The present invention relates to a slope stabilization structure, and more specifically, to a slope stabilization structure that has measures in place to prevent slope erosion caused by deer feeding damage.

Traditionally, a common measure to prevent landslides and other slope failures has been to harden the slope with concrete. However, hardening a slope with concrete requires cutting down all the trees on the slope, which creates the problem of destroying the natural environment.

The applicant therefore developed a rebar insertion method in which holes are drilled at regular intervals in the slope, rock bolts are inserted and solidified with grout, support plates are attached to the outer ends of the rock bolts, and the outer ends of the rock bolts are fastened together with wire ropes to prevent cliff collapses and also preserve the natural environment and scenery (see Patent Documents 1 and 2).

For example, Patent Document 1 discloses a natural slope stabilization method and structure in which multiple anchors 1 with bending rigidity are inserted into the soil in an appropriate arrangement on a natural slope, a support plate 2 is attached to the head of each anchor 1, and the heads of each anchor 1 are connected with a flexible linear or band-like head connector 3, in which the anchors 1 and support plate 2 resist the slope displacement in the early stages, and when the slope displacement becomes large to a certain extent, the resistance of the head connector 3 is added to the resistance of the anchors 1 and support plate 2 (see claim 1 in the scope of claims of Patent Document 1, paragraphs [0014] to [0031] of the specification, and Figures 1 to 4 of the drawings, etc.).

Patent Document 2 discloses a slope stabilization method and structure for preventing soil runoff, which involves installing multiple anchors on a slope, attaching and fastening bearing members to the heads of each anchor to apply bearing pressure to the ground, and connecting the heads of each anchor with a rope, and which is characterized in that a surface soil runoff suppression member capable of blocking the movement of surface soil down the slope is attached to the rope (see claim 1 in Patent Document 2, paragraphs [0018] to [0027] of the specification, and Figures 1 to 6 of the drawings, etc.).

The natural slope stabilization method described in Patent Document 1 and the slope stabilization method for preventing soil erosion described in Patent Document 2 are carried out without modifying the slope, so processes such as tree felling, cutting, slope shaping, and vegetation work can be omitted, which not only reduces costs and shortens construction time, but also maintains the landscape and environment, contributing to ^CO2 reduction and biodiversity conservation.

However, in recent years, there has been concern that the deer population has become so large in some areas that it has eaten up the vegetation surrounding the slope control structure described in Patent Document 1 and the slope stabilization structure described in Patent Document 2, leaving the mountains bare and causing rainwater to wash away soil from the ground surface, creating gaps between the bearing plates and the ground, reducing the bearing pressure and impeding slope stabilization.

One solution to this problem would be to set up fences to stop deer from entering. However, if the fence is too low, deer can easily jump over it, and if it is too high, there is a high risk that it will collapse or be damaged in strong winds such as typhoons, so the fence needs to be made sturdy, which increases installation costs. Electric fences could also be considered, but they require a constant voltage of over 4,000V, which increases maintenance costs.

In other words, vertical fences have the problem of high installation and maintenance costs. For this reason, there is a strong demand for simple measures to prevent deer intrusion that are low in installation costs and easy to maintain.

On the other hand, as a planar measure to prevent the intrusion of herbivores, Patent Document 3 discloses an animal intrusion prevention device that digs a trench in the passageway leading to the farm entrance and installs a grating to prevent wild animals such as deer and wild boars from invading the farm and to prevent damage caused by them eating crops (see claim 1 in the claims of Patent Document 3, paragraphs [0013] to [0027] of the specification, and figures 1 to 3 of the drawings, etc.).

However, the animal intrusion prevention device described in Patent Document 3 requires digging a trench at least 200 mm deep, which means installation costs are high, and the device is unable to solve this problem. In addition, no consideration was given to stabilizing the slope to prevent it from collapsing.

Patent document 4 discloses a device for preventing damage caused by herbivores, which covers a protected area 1 by placing a net-like body 2 above it via spacers 3 (see claim 1 in the claims of patent document 3, paragraphs [0019] to [0038] of the specification, Figure 1 of the drawings, etc.).

However, the device for preventing damage caused by herbivores described in Patent Document 4 is an invention based on the idea of preventing damage by physically keeping herbivores away from plants using a mesh body 2, and it is necessary to install the mesh body 2 over the entire area where damage needs to be prevented, which means it is unable to solve the problem of high installation costs. Also, as with Patent Document 3, no consideration was given to slope stabilization to prevent slope collapse.

JP 2001-049673 A JP 2004-324348 A JP 2011-160731 A JP 2004-73192 A

The present invention was devised in consideration of the above-mentioned problems, and its purpose is to provide a slope stabilization structure that can prevent slope collapses such as landslides, and can also prevent the intrusion of herbivores such as deer to prevent a decrease in the bearing pressure of the bearing plate due to damage caused by herbivores feeding on it.

The slope stabilization structure according to the first invention is a slope stabilization structure that is installed on a slope to stabilize the slope, and is characterized in that it comprises a plurality of rock bolts fixed at a predetermined interval into the ground of the slope, a plurality of nuts that screw onto the rock bolts, and a support plate that is attached to the rock bolts with the nuts and supports the ground to prevent the collapse of the slope, and that a bracket material is interposed between the support plate and the nuts, a net is stretched over the bracket material to prevent deer from entering, and the tension height of the net is maintained at a predetermined distance from the slope.

The slope stabilization structure according to the second invention is the first invention, characterized in that the net is stretched over at least a predetermined width from either the left or right end or the top or bottom end of the plurality of rock bolts so that deer cannot jump over.

The slope stabilization structure according to the third invention is characterized in that in the second invention, the net is stretched in a strip shape of a predetermined width so that deer cannot jump over it, surrounding the left and right ends and the upper and lower end rows of the multiple rock bolts.

The slope stabilization structure according to the fourth invention is characterized in that in the second or third invention, the predetermined width is 2.0 m or more and 5.0 m or less.

The slope stabilization structure according to the fifth invention is the first invention, characterized in that the specified distance is 300 mm or more and 600 mm or less.

The slope stabilization structure according to the sixth invention is any of the first to third inventions or the fifth invention, characterized in that the net is bent downward from either the left or right end or the top or bottom end row of the multiple rock bolts and stretched.

The slope stabilization structure according to the seventh invention is any one of the first to third inventions or the fifth invention, characterized in that the bracket material also serves as a washer for the nut.

The first to seventh inventions can prevent slope collapses such as landslides, and can also prevent damage caused by deer, i.e., when herbivores such as deer eat all the vegetation in the entire area of the slope stabilization structure, causing the ground to become bald and allowing rainwater to wash away the soil on the ground surface, creating gaps between the support plate and the ground, reducing the support pressure and impeding slope stabilization.

In particular, according to the second and fourth inventions, the net is stretched over a certain width over which deer cannot jump, so it is possible to reliably prevent deer from entering and prevent a decrease in support pressure due to damage caused by deer feeding.

In particular, according to the third and fourth inventions, the net is surrounded in a strip-like shape over a specified width that prevents deer from jumping over, so the area over which the net is stretched can be kept to a minimum while preventing deer from entering from all directions.

In particular, according to the fifth invention, the net can be stretched at a height where it is difficult for deer to walk, which makes it possible to more reliably prevent deer from entering and to prevent a decrease in support pressure due to damage caused by deer feeding.

In particular, the sixth aspect of the invention makes it possible to prevent deer from sticking their faces into the vegetation in the end rows to eat it, and to prevent a decrease in the support pressure of the support plates in the end rows.

In particular, according to the seventh invention, it is possible to eliminate the need for washers when tightening the lock bolt with a nut, thereby achieving cost reduction.

FIG. 1 is a front view of the overall configuration of a slope stabilization structure according to an embodiment of the present invention, viewed perpendicularly to a slope. FIG. 2 is a partially enlarged cross-sectional view mainly showing the subsurface structure of the slope stabilization structure. FIG. 3 is an enlarged view of part A in FIG. FIG. 4 is an enlarged view of part B in FIG. FIG. 5 is an enlarged view of a portion C in FIG. FIG. 6 is an enlarged view of a portion D in FIG. FIG. 7 is a view taken along the line E--E of FIG. FIG. 8 is a view taken along the line FF in FIG. FIG. 9 is a view taken along the line GG in FIG. Figure 10 is an enlarged view of the net of the slope stabilization structure folded toward the ground below, where (a) is a partially enlarged cross-sectional view showing the net cut, and (b) is a partially enlarged front view showing the vicinity of the end of the net.

Below, a slope stabilization structure according to an embodiment of the present invention will be described in detail with reference to the drawings.

The slope stabilization structure 1 according to an embodiment of the present invention will be described with reference to Figs. 1 to 10. Fig. 1 is a front view of the overall configuration of the slope stabilization structure according to an embodiment of the present invention, viewed perpendicularly to the slope, and Fig. 2 is a partially enlarged cross-sectional view mainly showing the subsurface configuration of the slope stabilization structure 1. Fig. 3 is an enlarged view of part A in Fig. 1, and Fig. 4 is an enlarged view of part B in Fig. 1. Fig. 5 is an enlarged view of part C in Fig. 1, and Fig. 6 is an enlarged view of part D in Fig. 1. Fig. 7 is a view taken along the arrows E-E in Fig. 5, and Fig. 8 is a view taken along the arrows F-F in Fig. 5. Fig. 9 is a view taken along the arrows G-G in Fig. 6.

As shown in Figures 1 and 2, a slope stabilization structure 1 according to an embodiment of the present invention is a structure that is installed on a slope G1 to stabilize the slope, and includes a number of rock bolts 2 fixed at a predetermined interval into the ground of the slope G1, a number of nuts 3 that screw onto the rock bolts 2, and a support plate 4 that is attached to the rock bolts 2 with the nuts 3 and supports the ground to prevent the collapse of the slope G1. In addition, a bracket material 5 is interposed between the support plate 4 and the nuts 3, and a net 6 is stretched over the bracket material 5 to prevent deer from entering.

As shown in Figure 1, the heads of the rock bolts 2 are connected to each other by a wire rope 7, which serves as a head connector, and are configured to integrate the rock bolts 2 together. Note that the illustrated form of the slope stabilization structure 1 is shown in Figure 1 etc. as a schematic simplification with an overall rectangular shape, but the overall shape of the slope stabilization structure 1 is appropriately set according to the shape of the slope on which it is to be installed or has been installed.

(Rock bolt)
The rock bolts 2 according to this embodiment are threaded steel rods that are fixed into the ground and function as anchor materials, and are installed at the vertices of an equilateral triangle at intervals of a predetermined distance D1 (D1=2m in this embodiment) when viewed from the front perpendicular to the surface, as shown in Fig. 1. Therefore, the horizontal interval D2 between the rock bolts 2 is 1.73m.

As shown in Figure 1, the slope stabilization structure 1 according to the illustrated embodiment has an overall width W1 of 40 m from the rock bolts 2 in the leftmost end row to the rock bolts 2 in the rightmost end row, and an overall installation length L1 of 25 m along the slope G1 from the rock bolts 2 in the uppermost end row to the rock bolts 2 in the lowermost end row.

As shown in FIG. 2, the rock bolt 2 is inserted into a hole h1 drilled in the slope G1, and is secured to the ground of the slope G1 by grouting the surrounding area with grout material G2.

As shown in Figure 2, the rock bolts 2 may be installed by adding additional bolts using couplers 20 as needed depending on the conditions of the soil layers on the slope.

(nut)
The nut 3 according to this embodiment is a typical commercially available nut made of cast iron. As shown in Fig. 2, a protective cap 30 with an inverted U-shaped (bell-shaped) cross section is attached around the nut 3 to prevent contact with the sharp ends of the nut 3 and the lock bolt 2.

(Support plate)
The support plate 4 according to this embodiment is made of steel and has the function of supporting the ground and preventing the collapse of the slope G1. The support plate 4 includes a support plate body 40 in the form of a hexagonal plate with the top of an equilateral triangle missing, and three reinforcing ribs 41 suspended from the support plate body 40 and extending radially from the center. The support plate body 40 is also provided with long holes 42 for weight reduction.

(Bracket material)
The bracket material 5 is a U-shaped member made of steel or the like and functions as a spacer for keeping a distance between the net 6 (described later) and the slope G1. The bracket material 5 according to this embodiment has a height of 22 cm.

As shown in Figures 3 to 5, 7, and 8, in the slope stabilization structure 1, the bracket material 5 sandwiches the end of the net 6 between the bracket material 5 and a fixing plate 50 made of a rectangular steel plate, and clamps and fixes it by tightening it with an M12 tightening bolt 51.

On the other hand, as shown in Figures 6 and 9, at the midpoint of the tensioning range of the net 6, such as part D in Figure 1 of the slope stabilization structure 1, the bracket material 5 does not have a fixing plate 50 attached, and it only acts as a spacer to prevent the net 6 from sagging and dropping downward.

The bracket material 5 can also be used as a washer for the nut 3. This is because it eliminates the need for a washer when tightening the lock bolt 2 with the nut 3, which can reduce costs.

(Net)
The net 6 is a member that has the function of preventing deer from entering the stretched area by making it difficult for them to walk, and is a diamond-shaped wire mesh woven with a mesh interval of 75 mm from steel wires with a wire diameter of φ3.2 m according to this embodiment, as shown in Figures 1, 3 to 6. Of course, the mesh interval is an example, and it is sufficient if the mesh interval is such that the deer's hooves can pass through and it is difficult for them to walk. In addition, if the form of the net 6 is other than the diamond-shaped wire mesh, it can be other welded wire mesh such as a tortoiseshell wire mesh or a lattice-type bundling wire mesh, and the material is not limited to metal and can be made of resin, etc., as long as the net does not bend too much when the deer try to walk on it and is not installed on a slope.

As shown in Figures 7 to 9, the height of the net 6 is the height of the support plate 4 plus the height of the bracket material 5, which acts as a spacer, and is maintained at a specified height H1 (a specified distance) from the slope G1. The specified height H1 is preferably 300 mm or more to make it difficult for the deer to walk, so that the deer will have difficulty in pulling out their legs. However, considering that the shoulder height of female Japanese deer is 60 cm to 110 cm, and that it would be better to set the height at 600 mm or less if the net is too high to allow the deer to crawl in and eat grass.

As shown in FIG. 1, in the slope stabilization structure 1 according to this embodiment, the net 6 is stretched over a predetermined width W2 from the upper and lower ends of the rock bolts 2, and over a predetermined width W3 from the left and right ends. In other words, in the slope stabilization structure 1, the net 6 is stretched so as to surround the left and right ends and the upper and lower end rows of the multiple rock bolts 2 in a strip-like shape (in the illustrated form, it is in a square shape). By surrounding the entire circumference of the slope stabilization structure 1 (all four circumferences in the illustrated form) in a strip-like shape with the net 6 that prevents deer from entering, it is possible to prevent deer from entering from all directions, from the upper and lower ends and the left and right ends, while minimizing the area in which the net 6 is stretched.

However, if the direction in which deer should be prevented from entering is limited due to conditions such as the topography of the slope G1, the stretching range of the net 6 only needs to be stretched over a specified width or more from either the left or right end or the top or bottom end of the row of lock bolts 2. This is because, if the direction in which deer should be prevented from entering is limited, this alone will be enough to prevent deer from entering.

As shown in FIG. 1, in the slope stabilization structure 1 according to this embodiment, the net 6 is stretched over a range of a predetermined width W2 = D1 x 2 = 4 m, which is two spans of the spacing D1 between the rock bolts 2, from the top and bottom ends, and over a range of a predetermined width W3 = D2 x 2 = 3.46 m, which is two spans of the horizontal spacing D2 between the rock bolts 2, from the left and right ends.

Of course, the stretched width of the net 6 is merely an example, and may be any width that prevents deer from jumping over. Specifically, it is considered to be 2.0m to 5.0m. However, considering that deer have greater jumping ability on flat surfaces, it is preferable that the stretched width of the net 6 be 3.0m or more, and considering that deer have less jumping ability on slopes, the upper limit may be 4.0m or less.

As shown in Fig. 10, the net 6 is preferably folded back downward from either or all of the left and right ends or the top and bottom ends of the rock bolts 2 toward the slope G1 (ground), and the ends of the net 6 are preferably fixed to the slope G1 with anchors 8 such as pegs driven into the ground. This is because it is possible to prevent herbivores such as deer from sticking their faces into the vegetation of the end rows to eat them, and it is possible to prevent a decrease in the support pressure of the support plates 4 of the end rows. Fig. 10 is an enlarged view of the net 6 of the slope stabilization structure 1 folded downward toward the ground, where (a) is a partially enlarged cross-sectional view showing the net 6 in a cut state, and (b) is a partially enlarged front view (plan view) showing the vicinity of the end of the net 6.

The slope stabilization structure 1 according to the present embodiment described above can prevent slope collapses such as landslides, and can also prevent damage caused by deer eating that would cause gaps to form between the support plate 4 and the ground of the slope G1, reducing the support pressure and impeding slope stabilization. In other words, the slope stabilization structure 1 can prevent deer from eating all the vegetation around the slope stabilization structure, causing the ground to become bald and allowing rainwater to wash away the soil on the ground surface.

In addition, with the slope stabilization structure 1, the net 6 is stretched over a certain width over which deer cannot jump, so it is possible to reliably prevent deer from entering and prevent a decrease in the supporting force due to damage caused by deer feeding.

In addition, the slope stabilization structure 1 encloses the net on all four sides at a specified width that prevents deer from jumping over, so it is possible to prevent deer from entering from all directions while minimizing the area in which the net is stretched.

Furthermore, with the slope stabilization structure 1, the net 6 can be stretched to a height of 300 mm to 600 mm, so the net can be stretched to a height where deer have difficulty walking, which more reliably prevents deer from entering and prevents a decrease in support pressure due to damage caused by deer feeding.

In addition, according to the slope stabilization structure 1, the net 6 is folded down and stretched from either the left and right ends or the top and bottom ends of the rock bolts 2, or from all end rows, so that deer can be prevented from sticking their faces into the vegetation in the end rows to eat them, and the support pressure of the support plates 4 in the end rows can be prevented from decreasing.

The above provides a detailed explanation of the slope stabilization structure 1 according to an embodiment of the present invention. However, the above-mentioned and illustrated embodiments are merely examples of embodiments that are embodied in implementing the present invention. Therefore, the technical scope of the present invention should not be interpreted in a limiting manner based on these.

1: Slope stabilization structure 2: Rock bolt 3: Nut 4: Support plate 40: Support plate body 41: Reinforcement rib 42: Long hole 5: Bracket material 50: Fixing plate 6: Net 7: Wire rope 8: Peg (anchor)
D1: Predetermined distance D2: Horizontal interval G1: Slope H1: Predetermined height W1: Overall width W2, W3: Predetermined width G2: Grout material h1: Hole

Claims (7)

A slope stabilization structure that is installed on a slope to stabilize the slope,
The method comprises: a plurality of rock bolts fixed at a predetermined interval into the ground of the slope; a plurality of nuts screwed onto the rock bolts; and a support plate attached to the rock bolts by the nuts to support the ground and prevent the collapse of the slope;
A slope stabilization structure comprising: a bracket material interposed between the support plate and the nut; a net for preventing deer from entering the slope; and a tensioned height of the net maintained at a predetermined distance from the slope. The slope stabilization structure according to claim 1, characterized in that the net is stretched over a predetermined width or more from at least one of the end rows at the left and right ends or the upper and lower ends of the plurality of rock bolts so that deer cannot jump over. 3. The slope stabilization structure according to claim 2, wherein the net is stretched in a strip shape of a predetermined width so as to surround the left and right ends and the upper and lower end rows of the plurality of rock bolts so that deer cannot jump over them. 4. The slope stabilization structure according to claim 2 or 3, wherein the predetermined width is 2.0 m or more and 5.0 m or less. The slope stabilization structure according to claim 1, wherein the predetermined distance is not less than 300 mm and not more than 600 mm. The slope stabilization structure according to any one of claims 1 to 3 or 5, characterized in that the net is bent downward and stretched from either one of the left and right ends or the upper and lower ends of the plurality of rock bolts. The slope stabilization structure according to claim 1 , wherein the bracket material also serves as a washer for the nut.

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