JP2004100237A - Earth retaining structure making use of steel-made screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an earth retaining structure making use of a steel-made screen capable of ensuring perpendicularity of earth and sand even after corrosion of thinnings and more reducing weight of a pressure support plate and more reducing costs thereof. <P>SOLUTION: A wall 3 comprises the steel-made screen 12 reinforced by a section steel 11, the thinnings 14 vertically and closely connected to the steel-made screen 12 through a clamping member 13 such as a binding wire or the like and a suction preventive material 15 placed on the back of the steel-made screen 12. The wall 3 supports a bolt 7 approximately horizontally set in a bedrock 1 by making use of a connecting metal fitting 16. Back filling soil 8 suitable for growing plants is thrown to the back of the wall 3 to form a planting zone 9 on the top section to plant a tree 10 so as to cover the wall 3. When an expand metal having durability for about thirty years is used for the steel-made screen 12, even if the thinnings 14 corrode, the durability of the wall 3 can be extended up to the limits of corrosion of the steel-made screen 12. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a soil retaining structure that forms a step-like tree planting zone on a slope to prevent collapse of a slope and promote greening, and particularly to a steel net that is rich in workability, economy, and durability against required earth pressure. The present invention relates to an earth retaining structure using as a pressure receiving plate.
[0002]
[Prior art]
2. Description of the Related Art In recent years, construction of a so-called green bench method for preventing collapse and greening by forming a flat ground on a slope with an emphasis on landscape protection and global environment conservation has been increasing. In this green bench construction method, a flat portion for erecting a wall is formed on the slope of a steep slope, and the wall is placed substantially vertically on this flat portion, and an anchor fixed to the ground is substantially perpendicular to the wall. In this method, soil and sand suitable for growing trees are buried in the upper part of the back of the wall to form a tree planting zone on the top of the wall, and the ground is strengthened by growing the trees.
[0003]
In the conventional green bench method, concrete panels with a height of about 1.5 m have been used as walls, but the concrete panels are too heavy compared to the earth pressure, and work when carrying them into or installing them on site There were difficulties in sex. There is also a disadvantage that the concrete part does not match the natural scenery until the tree grows to cover the panel.
[0004]
Accordingly, the applicant has previously proposed a soil retaining structure that uses thinned wood that has been left in large quantities without being determined for use in domestic forest resources, while reducing the weight and reducing the cost while improving the appearance. This earth retaining structure is described in Japanese Patent Application Laid-Open No. 2002-81075, and has a structure provided with a concrete pillar body supported by an anchor and erected at appropriate intervals and a thinning material tied horizontally via a fastener. In addition, the back of the thinned wood was backed with earth and sand suitable for growing trees, and when the thinned wood reached its expiration date as a structural material, the fastener was cut and replaced with a new material.
[0005]
This soil retaining structure proposed by the applicant enables the effective use of thinned wood in harmony with the natural scenery, and can be used with minimal processing of thinned wood, so that costs can be reduced and the weight of components can be reduced. Since it is realized, it has many advantages that it can be easily transported and the applicable range of the construction site can be expanded.
[0006]
[Problems to be solved by the invention]
However, thinned timber has not yet been actively used due to concerns about its durability against corrosion. Although the structure was reduced in weight, there was still room for improvement in terms of workability and economy because a concrete pillar supported by the anchor was used.
[0007]
The present invention has been made in order to solve the problems of the conventional earth retaining structure as described above, and can maintain the verticality of the earth and sand even after the thinned wood is corroded, and further reduce the weight of the pressure receiving plate. It is another object of the present invention to provide a retaining structure that can achieve lower cost.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the earth retaining structure of the present invention is characterized in that a steel net reinforced with steel is erected as a pressure receiving plate, and a tree is formed while a suction-preventing material having high water-sinking and drainage properties is interposed on the back of the steel net. And backing the pressure receiving plate with an anchor, and standing and locking a thinning material for reinforcing the pressure receiving plate on the front surface of the steel mesh. .
[0009]
This earth retaining structure is intended only to create a flat ground, and the pressure acting on the vertical wall surface is relatively small. Therefore, bolts are mainly used as anchors. A steel net reinforced with a steel material that is the main structure of the vertical surface is connected to bolts installed on the ground, and at this time, the horizontal force obtained from the ground acts as a reaction force to stabilize the vertical surface. It is desirable to use expanded metal which is excellent in workability, economy and durability for a required earth pressure for a steel net. If the durability of about 30 years is secured, even if the thinning material for reinforcement corrodes and loses the function as a reinforcing member of the wall, the durability can be extended to the limit of corrosion of the steel net. it can.
[0010]
If the number of trees to be planted on the horizontal surface is about 20 years, the pressure on the wall surface will be reduced because the foundation for the growth of trees is already maintained when the thinned wood is eroded. And no new reinforcements are needed. After the steel net is corroded, its role is replaced by tree growth, eventually achieving the same slope stability as a natural forest. Further, after the iron product is corroded, the important mineral elements are reduced by the elution of iron into the soil to provide nutrients indispensable for the growth of living organisms.
[0011]
The steel net is reinforced so as to have the required rigidity with steel materials arranged at appropriate intervals in the horizontal and vertical directions, for example, shape steel such as angle steel, but by making use of the rigidity of the thinned wood standing upright on the front. The steel in the vertical direction can be omitted. Thinned timber is used by cutting the timber generated by logging in a more natural state with minimal processing, just to trim the length. Since the thinned wood can be directly tied using an arbitrary hole of the net, the mounting operation is very simple. In addition, the diameter of the thinned lumber is generally irregular, but in the mainland retaining structure, since it is used for reinforcing the net, it is not necessary to secure a strict uniform arrangement, and all irregularities in the material can be tolerated.
[0012]
The drainage prevention material is made of a material with excellent drainage and air permeability, such as coconut fiber, to prevent the outflow of sediment while allowing water to permeate, and to supply oxygen necessary for growing the roots of the trees to be planted. Thoroughly work to enhance the ability to regenerate nature. As the backing soil suitable for growing trees, ground excavated soil and naturally existing topsoil are used, and if necessary, the soil is created to create a step-like plantation space. The flat ground on the slopes promotes vegetation growth, thus creating a mutually beneficial relationship in which the ground itself is reinforced by tree roots and protected from the effects of rainfall. Trees are fixed to the ground in order to extend their roots for their own growth and stability against weather such as wind, so the role of the mainland retaining structure is gradually reduced over time.
[0013]
Anchors are anchor bars that are installed at the most efficient angle, that is, horizontally or very close to the ground, to secure and stabilize the ground and to cope with the horizontal force on the steel net, and fixed in the ground. It is desirable to connect to the steel net with a simple fitting that makes use of the structure of the screw and the nut. As an example of the metal fittings, it is composed of a column with a plate inserted from the front surface of a steel net, and a cylinder that is screwed to the column and internally locks an anchor bar with a nut in a universal joint shape. Connection fittings and the like are conceivable. Also in this case, since the attachment can be performed by using an arbitrary hole of the net, the connection with the anchor bar can be easily and rationally performed. There are two ways to fix the anchor bar to the ground: a method of driving a fixing bolt into the ground or a support plate method that is buried in the ground perpendicular to the anchor bar, depending on the topography and geological conditions. Is carried out, and rationality and economy are achieved.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of an 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 ground 1 to which this earth retaining method is applied is a stable slope which is geologically capable of implanting bolts. A flat portion 4 for mounting the wall 3 by shaving the slope 2 of such a steep slope is formed along the contour line, and a rising portion 6 for forming the bolt hole 5 is appropriately formed.
[0015]
The wall 3 is supported by bolts 7 installed substantially horizontally on the ground 1, into which a backing soil 8 suitable for growing trees is fed, and a horizontal or gentle slope planting zone 9 is stepped on the top. A tree 10 is formed on each step so as to cover the wall 3. The wall 3 has a height of about 1.5 meters and is formed for each step. For example, when cutting is performed from above, first, the uppermost wall 3 is installed, and then the lower slope 2 is shaved, and the excavated earth and sand is divided into topsoil and other soil and temporarily placed. A bolt hole 5 is formed in the rising portion 6 using the lower flat portion 4 formed, and a bolt 7 is driven into the ground 1 and fixed with grout or the like. The lower wall 3 is connected with bolts 7, and the temporarily placed soil and topsoil are introduced as backing soil 8 to form a new planting zone 9. In accordance with the above procedure, the slope 2 is cut down sequentially while the slope 2 is cut down to minimize waste, and a work platform is secured for safety.
[0016]
The wall 3 is provided with a steel net 12 reinforced by a mold steel 11, a thinning material 14 which is vertically tied to the steel net 12 via a fastening member 13 such as a binding wire, and a rear surface of the steel net 12. It is composed of a suction prevention member 15 to be provided. In the steel net 12 used in this embodiment, as shown in FIG. 4, the shape steels 11 are arranged at appropriate intervals in the horizontal and vertical directions. Can be omitted.
[0017]
A connection fitting 16 is used to support the wall 3 with bolts 7. Details of the connection fitting will be described with reference to FIG. FIG. 5 is an enlarged vertical sectional view of the bolt connection portion. The connection fitting 16 includes an insert 17 inserted from the front of the steel net 12, an insert plate 18 interposed between the insert 17 and the steel net 12, and a cylindrical body screwed to the insert 17 on the back of the steel net 12. It consists of 19. The insert 17 has a rectangular or circular support plate 17a and a threaded column 17b projecting from the center of the support plate 17a. The bolt 7 fixed to the ground is screwed with a nut 7a at the end on the steel net 12 side. To wear. The cylindrical body 19 has a convex portion 19a provided on the inner surface thereof, and after screwing a nut 7a into a bolt 7 inserted from the outside, the nut 7a is hooked in a universal joint shape. On the other end of the inner surface of the cylindrical body 19, a female screw 19b is threaded and screwed with the threaded column 17b.
[0018]
Since the insert 17 can pass through an arbitrary mesh of the steel net 12, it is easy to adjust the position of the bolt 7, and if the bolt 7 is within a predetermined range, the cylindrical body 19 and the insert 17 can be connected even if the bolt 7 is inclined in all directions. Can be connected. For this reason, installation of the bolt 7 becomes easy. The column structure can be omitted by directly connecting the bolt 7 and the steel net 12. Even though the steel net 12 is reinforced by the mold steel 11, the weight is increased by about 10 kg per square meter, and this type of construction method, which is often used on slopes, achieves a remarkable reduction in weight and significantly improves workability. improves.
[0019]
In the above-described earth retaining structure, the case where the fixing bolt is driven into the ground has been described. However, a method in which the anchor plate is fixed to the rear end of the bolt and this is embedded in the ground may be used. The use of a steel net is effective even when a horizontal plane is to be provided on the slope of a cut or embankment slope or a natural slope. By taking advantage of the strong pull-out strength of the fixing bolts driven into the slope, it is possible to obtain a stable horizontal surface supported by the fixing bolts by embedding earth and sand cut from above the steel net into the net.
[0020]
The horizontal surface can be used as a tree planting space, and has important value as a promenade and management road. Moreover, when constructing the embankment, it is possible to collect rainwater by burying a perforated pipe or the like. This expands the function of the green dam that forests originally have, and can be 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 part to the upper part and use a plurality of horizontal fixing bolts to develop a construction approach road or increase the number of lanes.
[0021]
【The invention's effect】
As described above, the earth retaining structure of the present invention uses the steel net reinforced with steel as the pressure receiving plate, and the thinning material for reinforcement is erected and locked on the steel net, so that the thinning material having a short service life is corroded. After that, the durability can be extended to the limit of corrosion of the steel mesh, and the verticality of the earth and sand can be secured during this time. Further, even if the steel net increases in weight due to the reinforcement by the steel material, it is about 10 kg per square meter, so that the wall can be remarkably reduced in weight and the workability is remarkably improved. Further, since any irregularity of the thinned wood can be tolerated, the cost can be further reduced.
[Brief description of the drawings]
FIG. 1 is a sectional view of an earth retaining work.
FIG. 2 is a partially enlarged sectional view of FIG.
FIG. 3 is a sectional view showing a section taken along line III-III of FIG. 2;
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 3 Wall 7 Bolt 8 Backfill 10 Tree 11 Shape steel 12 Steel net 13 Fastening member 14 Thinning material 15 Suction prevention material 16 Connection fitting

Claims (1)

A steel net reinforced with steel is erected as a pressure receiving plate, and backside of the steel net is filled with soil and sand suitable for growing trees while interposing a suction-preventing material having high water-absorbing and draining properties. An earth retaining structure, wherein a plate is supported by an anchor, and a thinning material for reinforcing a pressure receiving plate is erected and locked on a front surface of the steel mesh.

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