JP3799403B2 - Earth retaining structure using steel mesh - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a soil retaining structure that contributes to preventing slope failure and promoting greening by forming a stepped tree-planting zone on a slope, and in particular, a steel net that is rich in workability, economy, and durability against required earth pressure. The present invention relates to a soil retaining structure that uses as a pressure receiving plate.
[0002]
[Prior art]
In recent years, with an emphasis on landscape protection and global environmental conservation, the construction of so-called green bench methods for preventing flattening and greening by forming a flat ground on the slope is increasing. In this green bench method, a flat part for standing a wall is formed on the slope of a steep slope, the wall is placed substantially vertically on this flat part, and the anchor fixed to the ground is almost orthogonal to the wall. This is a construction method in which earth and sand suitable for the growth of trees are backed up on the upper back of the wall body to form a planting zone at the top of the wall body, and the ground is strengthened by the growth of the tree.
[0003]
In the conventional green bench construction method, a concrete panel with a height of about 1.5m has been used as the wall, but the concrete panel is too heavy compared to the earth pressure, and work for carrying in and installing on the site. There was a difficulty in sex. In addition, there was a drawback that the concrete portion did not match the natural landscape until the tree grew to cover the panel.
[0004]
Therefore, the applicant previously proposed a soil retaining structure that uses thinned wood that has been left untreated for a long time in domestic forest resources, while reducing the weight and reducing the cost. This earth retaining structure is described in Japanese Patent Application Laid-Open No. 2002-81075, and is a structure including a concrete pillar body that is supported by an anchor and is erected at an appropriate interval, and a thinning material that is tightened horizontally via a fastening bracket. The back of the thinned wood was backed with earth and sand suitable for tree growth, and when the thinned wood reached the expiration date for use as a structural material, the fastener was cut and replaced with a new material.
[0005]
This soil retaining structure proposed by the applicant enables effective use of thinned wood that harmonizes with the natural landscape, and can be used with only minimal processing on the thinned wood, thus reducing costs and reducing the weight of components. Since it is realized, it has many advantages that it is easy to transport and expands the scope of construction.
[0006]
[Problems to be solved by the invention]
However, since thinned wood is uneasy in terms of durability against corrosion, it has not been actively used. Although the structure was lighter, there was still room for improvement in terms of workability and economy because of the use of concrete pillars supported by anchors.
[0007]
The present invention was made to solve the problems of the conventional earth retaining structure as described above, and can ensure the verticality of the earth and sand even after the thinned wood is corroded, making the pressure plate lighter. In addition, an object of the present invention is to provide a soil retaining structure capable of reducing costs.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the earth retaining structure of the present invention is provided with an expanded metal reinforced as a pressure receiving plate, which is reinforced so as to have the required rigidity with a steel plate arranged at appropriate intervals in both the horizontal direction and the horizontal and vertical directions , The back of this expanded metal is backed with earth and sand suitable for tree growth while interposing an anti-suction material with high water absorption and drainage properties, and a connection fitting directly connected to the pressure receiving plate , and the connection fitting in a universal joint shape. It is supported by an anchor to be locked, and a thinning material for pressure-receiving plate reinforcement is erected and locked on the front surface of the expanded metal .
[0009]
This earth retaining structure is exclusively for the purpose of creating a flat ground, and the pressure acting on the vertical wall surface is relatively small. Therefore, bolts are mainly used as anchors. The steel net reinforced with the steel material that is the main structure of the vertical surface is connected to the bolts installed on the natural ground, and the horizontal force obtained from the natural ground at this time acts as a reaction force to stabilize the vertical surface. It is desirable to use an expanded metal that is rich in workability, economy and durability against the required earth pressure for the steel net. If durability for about 30 years is secured, even if the thinning material for reinforcement corrodes and loses its function as a reinforcing member for the wall, the durability can be extended to the limit of corrosion of the steel net. it can.
[0010]
If the growing age of trees planted on a horizontal surface is about 20 years, the base for the growth of the trees is maintained when the thinned wood is corroded, so the pressure acting on the wall is reduced. New reinforcement is not required. After the steel mesh is corroded, its role is surrogate by growing trees and finally the slope stability similar to that of a natural forest is realized. In addition, after iron products are corroded, iron is eluted into the soil, so that important mineral elements are reduced and provide essential nutrients for the growth of organisms.
[0011]
Steel nets are reinforced with steel materials, such as angle steels, arranged at appropriate intervals in the horizontal and vertical directions to maintain the required rigidity, but by utilizing the rigidity of thinned wood standing up front. The steel material in the vertical direction can be omitted. For thinned wood, use the timber produced by logging with minimal processing in a more natural state to the extent that the length is trimmed. Since thinned wood can be tied directly using any hole in the net, installation work is very simple. In addition, the diameter of thinned wood is generally uneven, but the main retaining structure is used to reinforce the net, so it is not necessary to ensure a strict uniform arrangement, and any uneven material can be allowed.
[0012]
Use a material with excellent drainage and breathability as an anti-suction material, such as coconut fiber, to prevent the outflow of earth and sand while allowing water to penetrate, and to supply oxygen necessary for the growth of tree roots to be planted Sufficiently do it to increase natural regeneration. As the backfill suitable for the growth of trees, natural ground excavated soil and naturally existing topsoil are utilized, and if necessary, customer soil is used to create a step-like afforestation space. The flat ground on the slope promotes the growth of vegetation, and as a result, the ground itself is reinforced by the roots of the trees and further protects against the influence of rainfall, creating a mutually beneficial relationship. Since trees grow their roots for their growth and stability against wind and other weather conditions, the shape of the mainland structure is gradually reduced over time because the shape is fixed integrally with the ground.
[0013]
Anchors are installed at the most efficient angle, that is, at an angle that is horizontal or very close to the purpose of coping with the strength and stability of the natural ground and the horizontal force applied to the expanded metal. It is desirable to connect to expanded metal with simple metal fittings that make use of the screw and nut structure. The connection bracket in the earth retaining structure according to claim 2, an insert for inserting a threaded column projecting from the front surface of the expanded metal projecting from the center of the support plate, an insert plate interposed between the insert and the expanded metal, It has a cylinder body screwed to the threaded column of the insert on the back surface of the expanded metal, and the anchor is hooked on the cylinder body in a universal joint shape. As an example of metal fittings, a connection consisting of a column with a plate that is inserted from the front surface of the expanded metal , and a cylindrical body that is screwed to this column and locks an anchor bar with a nut into a universal joint. A metal fitting etc. can be considered. Also in this case, since it can be attached using an arbitrary hole of the net, the connection with the anchor bar can be easily and rationally performed. There are two methods for fixing the anchor bar to the ground: a method of driving a fixing bolt into the ground and a bearing plate method that is buried in the ground perpendicular to the anchor bar, but this is selected according to topography and geological conditions. Is carried out, and rationality and economy are achieved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 is a cross-sectional view of a earth retaining work constructed on a steep slope, FIG. 2 is a partially enlarged cross-sectional view thereof, and FIG. 3 is a cross-sectional view showing a III-III cross section of FIG. The natural ground 1 to which this earth retaining work is applied is a geological and stable slope in which bolts can be implanted. The flat part 4 for installing the wall 3 by cutting the slope 2 of such steep slope is formed along the contour line, and the rising part 6 for drilling the bolt hole 5 is appropriately formed.
[0015]
The wall 3 is supported by bolts 7 that are installed almost horizontally on the ground 1, and a backside soil 8 suitable for tree growth is placed on the back of the wall 3, and a horizontal or gentle slope planting zone 9 is gradually formed on the top. A tree 10 is formed so as to cover the wall 3 at each stage. The wall 3 is about 1.5 meters high and is formed for each stage. For example, when cutting from above, the uppermost wall body 3 is first installed, then the lower slope 2 is shaved, and the excavated earth and sand is divided into topsoil and other debris and temporarily placed. A bolt hole 5 is drilled in the rising portion 6 using the lower flat portion 4 formed, and the bolt 7 is driven into the natural ground 1 and fixed by a grout or the like. The lower wall body 3 is connected with bolts 7, and temporarily placed earth and topsoil is added as back soil 8 to form a new planting zone 9. In addition to eliminating as much as possible the waste of the earth and sand obtained by scraping the slope 2 while cutting down sequentially by the above procedure, work safety is ensured by securing a working scaffold.
[0016]
The wall 3 is arranged on a steel net 12 reinforced with a steel plate 11, a thinning material 14 that is vertically connected to the steel net 12 via a fastening member 13 such as a binding wire, and a back surface of the steel net 12. It consists of the suction prevention material 15 to provide. As shown in FIG. 4, the steel net 12 used in this embodiment has the steel plates 11 arranged at appropriate intervals in the horizontal and vertical directions. However, by utilizing the rigidity of the thinned wood standing on the front surface, the vertical direction is obtained. It is also possible to omit the shape steel.
[0017]
A connection fitting 16 is used to support the wall 3 with the bolt 7. Details of the connection fitting will be described with reference to FIG. FIG. 5 is an enlarged longitudinal sectional view of the bolt connecting portion. The connection fitting 16 includes an insert 17 inserted from the front surface of the steel mesh 12, an insert plate 18 interposed between the insert 17 and the steel mesh 12, and a cylindrical body screwed to the insert 17 on the rear surface of the steel mesh 12. 19. The insert 17 has a support plate 17a formed in a rectangular shape or a circular shape, and a threaded column 17b projecting from the center thereof. The bolt 7 fixed to the natural ground is screwed with a nut 7a at the end of the steel net 12 side. To wear. The cylindrical body 19 is provided with a convex portion 19a on its inner surface, and after a nut 7a is screwed into a bolt 7 inserted from the outside, it is hooked on a universal joint. A female screw 19b is screwed into the other end of the inner surface of the cylinder 19 and screwed with the threaded column 17b.
[0018]
Since the insert 17 can pass through any mesh of the steel mesh 12, it can be easily aligned with the position of the bolt 7, and if it is within a predetermined range, the cylinder 19 and the insert 17 can be connected even if the bolt 7 is inclined in any direction. Can be connected. For this reason, installation of the bolt 7 becomes easy. Further, the column structure can be omitted by directly connecting the bolt 7 and the steel net 12. Even if the steel net 12 is increased in weight by the reinforcement of the shape steel 11, it is about 10kg per square meter, and this type of construction method is often used on sloping ground. improves.
[0019]
In the soil retaining structure described above, the case where the fixing bolt is driven into the natural ground has been described, but an anchor plate may be fixed to the rear end of the bolt and embedded in the natural ground. The use of steel nets is also effective in the case where a horizontal surface is to be provided in the middle of an existing cut / fill slope or natural slope. By utilizing the strong pulling strength of the fixing bolt driven into the slope, it is possible to obtain a stable horizontal plane supported by the fixing bolt by embedding earth and sand cut out from above the steel mesh.
[0020]
In addition to being used as a planting space, the horizontal plane has an important value as a promenade and administrative road. It is also possible to collect rainwater by embedding a perforated pipe or the like when constructing the embankment. This expands the function of the green dam that the forest originally has, and it can serve as a powerful alternative in the era of dam removal by maximizing the water storage function of the soil. When a wide horizontal surface is required, it is possible to gradually move from the lower stage to the upper part and use a plurality of horizontal fixing bolts to develop a construction approach path or lane extension.
[0021]
【The invention's effect】
As described above, the earth retaining structure of the present invention uses an expanded metal reinforced with a steel plate as a pressure receiving plate so as to have the required rigidity, and stands up and locks the thinning material for reinforcement thereto, so that the service life is short. Even after the thinned wood is corroded, the durability can be extended to the limit of the corrosion of the expanded metal , and the verticality of the soil between these can be ensured. Moreover, even if the expanded metal is increased in weight by reinforcement with the steel mold , it is about 10 kg per square meter, realizing a significant weight reduction of the wall body, and the workability is remarkably improved. Moreover, since all irregularities of thinned wood can be tolerated, the cost can be further reduced. Further, since the connection fitting directly connected to the pressure receiving plate is used, the column structure which is the main structure of the vertical plane can be omitted. Further, since the connection fitting and the anchor are locked in a universal joint shape, the anchor can be connected even if the anchor is inclined in any direction within the predetermined range, and the anchor can be easily installed. In addition, since the metal fitting in the earth retaining structure according to claim 2 uses an insert inserted from the front surface of the expanded metal, it can be attached using any hole in the mesh, so that it can be easily aligned with the anchor position and connected to the anchor. Is easy and reasonable.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a earth retaining work.
FIG. 2 is a partially enlarged cross-sectional view of FIG.
3 is a cross-sectional view showing a III-III cross section of FIG.
FIG. 4 is a front view of a steel net.
FIG. 5 is an enlarged vertical sectional view of a bolt connection portion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ground mountain 3 Wall body 7 Bolt 8 Backfill earth 10 Tree 11 Type steel 12 Steel net 13 Fastening member 14 Thinning material 15 Suction prevention material 16 Connection metal fitting

Claims (2)

Expanded metal reinforced with steel molds arranged at appropriate intervals in the horizontal direction or both horizontal and vertical directions so as to have the required rigidity is erected as a pressure receiving plate, and a suction prevention material with high water absorption and drainage properties on the back side of this expanded metal Supporting with a fitting that directly connects to the pressure plate and an anchor that locks the fitting in the shape of a universal joint, and supports the front surface of the expanded metal An earth retaining structure characterized in that a thinning material for reinforcing a pressure-receiving plate is vertically installed and locked. The connecting bracket includes an insert for inserting a threaded column projecting from the center of the support plate from the front surface of the expanded metal, an insert plate interposed between the insert and the expanded metal, and a back surface of the expanded metal. 2. The earth retaining structure according to claim 1, further comprising: a cylindrical body that is screwed onto a threaded column body, wherein the anchor is hooked on the cylindrical body in a universal joint shape.

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