JP2002339335A - Vegetation mat for revetment work by reinforced earth and its working method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a revetment method by reinforced earth and vegetative mats capable of fully withstanding a river levee having a flow speed of 2 m/s but also a river revetment where the velocity of river flow is expected to be 4 to 5 m/s. SOLUTION: For forming a retaining wall 30 for river revetment by using the vegetative mat A for revetment with reinforced earth, an earth retaining unit 2 having an L-type net-shaped panel rising portion 3 by expanded metal or the like and an earth retaining unit 2 having the rising portion 3 of L-type net-shaped rising portion 3 by expanded metal and a bottom side portion 4 is arranged in which geogrid 7 is continuously arranged in the basic construction, and the vegetation mat A for revetment with reinforced earth is adhered to the inner side of the net-shaped rising portion, thereafter, soil is filed and compacted to a filling 8 on the geogrid of the bottom side portion and the above procedure is repeated and the earth is gradually filled to upper stages thereby building a wall 30 for the river revetment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the construction of a river embankment retaining wall, particularly a steep slope having an inclination angle of 70 to 80 degrees, and a river embankment retaining wall on an inclined ground such as a ground or a land development site and a road. The present invention relates to a reinforced earth method that is suitable for performing a greening process.

[0002] In particular, the present invention relates to a vegetation mat for a reinforced soil revetment and a method of constructing the reinforced soil revetment, which are preferably used as the river revetment.

[0003]

2. Description of the Related Art There are various types of river revetment works, but in areas where there is not enough land, steep slopes are inevitable. Has been implemented. However, in recent years, the construction of multi-natural rivers has been demanded from the viewpoint of environmental conservation, and the use of environmental blocks for introducing vegetation between blocks and the study of reinforced soil revetment works using geotextiles have been studied.

However, conventional environmental blocks do not provide sufficient vegetation to grow, and an attempt has been made to use, for example, a geogrid-reinforced earth method, which is conventionally used for road slopes and river protection walls, for river protection. However, river revetment retaining walls by the reinforced earth method used for roads, etc., do not take into account the suction of backfill embankment soil by running water from the river, so the revetment formed in this way is easily constructed. There was a problem of collapse.

In order to solve the above problems, it is very important to prevent the soil from being sucked out on a slope that is suitable for flowing water at the time of flooding, such as a river bank.
In order to reduce the nearby flow rate, a thick net or mat is installed on the surface and the surface is covered with vegetation. (If the flow velocity can be reduced, suction can be greatly suppressed.) By covering the entire surface with vegetation, surface erosion is prevented by the root system and foliage of the plant. The use of thick nets and mats, which have a small weight, suppresses the suction of soil. It is conceivable to install a suction prevention sheet on the back or surface of the vegetation.

[0006] However, it is very difficult to cover the surface with vegetation and prevent erosion and soil wicking under 5 minute gradient conditions compatible with running water. Generally, river revetment works using vegetation are targeted at a flow velocity of 2 m / s or less. However, river revetment works using general vegetation are also subject to river water protection when exposed to flowing water with a flow velocity of 2 m / s or more for a long time. Due to the fluid force, the surface soil is gradually washed away, and the root system of the vegetation is eventually exposed, and eventually the root system is cut off and the vegetation is washed away, which leads to collapse of the embankment.

[0007]

SUMMARY OF THE INVENTION The present invention, as a result of studying the above-mentioned reinforced soil construction method effective for river revetment, shows that not only a river embankment with a river velocity of 2 m / s but also a river velocity of 4 to 5 m / s. An object of the present invention is to provide a reinforced soil revetment method that can sufficiently withstand expected river revetments and a vegetation mat used for the method. Special attention must be paid to the method of entanglement of the plant root system with a net such as a polynet to prevent scouring and cutting of the root system, which is a weak point of the introduced vegetation, and to the method of soil embankment on the back of the reinforced soil revetment. It is to prevent sucking out.

[0008]

SUMMARY OF THE INVENTION The present invention has a thickness of 5 to 20 mm.
A mesh nonwoven fabric capable of germinating and rooting is bonded to a mat in which germinable fibers of foliage of plants having a porosity of about 85 to 95% with a porosity of about mm are entangled at random, and seeds, fertilizer, and soil are attached to the nonwoven fabric. This is a vegetation mat for reinforcing soil revetment to which one or more of an improvement material and a water retention material are attached (Claim 1).

[0009] When a river revetment is carried out by the reinforced earth method using such a vegetation mat for reinforced soil revetment, the plant seeds adhered to the mesh nonwoven fabric will germinate and grow, and the rhizomes of the plant seeds will be formed of the mesh nonwoven fabric and fibers. Entangled in mats that are entangled randomly, and spread in soil buried inside the reinforced earth method. As a result, even if the river revetment retaining wall made by the reinforced earth method was submerged by the rising water of the river, the foliage and fibers of the plants that grew on the front surface were randomly entangled in the front with the reinforced earth method. The mat can reduce the surface flow velocity. On the other hand, as described above, the rhizomes of the plants that grew on the river embankment are entangled with the mat in which the nonwoven fabric and fibers are randomly entangled, and spread to the soil inside the river embankment to bind the soil. However, even if the river revetment retaining wall by the reinforced earth method may be submerged as described above, it is possible to appropriately prevent the suction of the soil in the river revetment retaining wall and stably maintain the river revetment retaining wall. At the same time, the surface of the river bank can be permanently covered with plants, and the landscape of the river bank can be improved.

The second invention uses a durable net having a mesh size of 5 to 15 mm in place of the mat in which the fibers are randomly entangled, and a mesh nonwoven fabric capable of budding and rooting. , And one or more of seed, fertilizer, soil conditioner and water retention material were attached to the nonwoven fabric (Claim 2).

[0011] In the second invention as well, similarly to the first invention, the river rises due to the vegetation on the front surface of the river revetment wall and the binding of the soil in the river revetment wall by the rhizome, thereby increasing the river revetment. Even if the wall is submerged and the load of fluid force is applied to the river revetment wall, the river revetment retaining wall formed as a river revetment has an extremely stable revetment function by reducing the surface flow velocity and preventing suction. Demonstrate.

[0012] A slow-release fertilizer zone is attached near the top along the extension direction of the reinforced soil revetment vegetation mat of the first and second inventions (claim 3).

By adopting this configuration, for example, in a reinforcing earthwork unit stacked in two stages, the rhizomes of the plants growing in the lower part of the upper part are placed on the top of the above-mentioned reinforcing soil revetment vegetation mat in the upper part of the lower part. It grows in search of fertilizer in the attached slow-release fertilizer zone, spreads near the upper and lower two-stage border,
Even if the nearby soil is tied up and the river rises, the river revetment retaining wall by the reinforced earth method may be submerged,
It is possible to effectively prevent the suction of the soil inside the river protection wall.
In particular, a geogrid material is laid in the vicinity of the upper and lower two-step boundary for the purpose of stabilizing the reinforced soil river embankment retaining wall. However, by adopting the above configuration, it can be prevented beforehand, and the stability of the river bank retaining wall is further improved.

According to a third aspect of the present invention, there is provided a basic structure in which an earth retaining unit having an L-shaped rising portion and a bottom portion is disposed on the river revetment retaining wall construction side, and a geogrid is connected to the bottom portion. A vegetation mat for reinforced soil revetment according to claim 1, 2 or 3,
After that, the soil was laid on the geogrid at the bottom and compacted, and then the above procedure was repeated to fill the upper tier one by one and build a river embankment wall. A method (claim 4).

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment of the Invention)
An embodiment of a vegetation mat A for reinforced soil revetment according to the present invention will be described in detail with reference to the drawings. The mat 1 in which fibers used in the present invention are randomly entangled is made of nylon,
Melt polyethylene, polypropylene, vinyl chloride, etc., extrude from a fine nozzle, randomly entangle this fiber at the time of extrusion, form a thickness of 5 to 20 mm, cool by natural cooling or cold water, porosity 85 ~ A 95% mat 1 is formed. Other methods of forming the mat 1 include a non-woven mat in which relatively durable plant fibers such as coconut fibers are laminated loosely, and a thin metal fiber in which laminations are randomly laminated (scraping). . In any case, the plant has pores that allow the plants to germinate. The standard of the mat 1 is that the height of the rising portion 3 on the front surface of the retaining unit 2, that is, the retaining unit 1 has a height of 50 cm.
In this case, if the gradient is 5 minutes, the rising portion 3 is 57 cm, has a width of about 60 cm, and the extension direction is 1.0 to 10 m.

The nonwoven fabric 5 having a mesh used in the present invention
For example, polyester, vinylon, made of corrosion-resistant synthetic fibers such as nylon, in the vertical and horizontal directions, for example, between 0.5 to 10 mm, a sparse part and a dense part formed with a width of 0.3 to 5.0 mm It has a state of being arranged alternately. In other words, the sparse portion is such that the material forming the nonwoven fabric 5 is reduced or absent, so that the buds and roots of the plant can easily pass through, and the sparse portion does not pass through or is difficult to pass through. The dense portion is a portion in which the material forming the nonwoven fabric 5 is densely packed more than a certain amount and does not pass or is hard to pass through the buds, roots and soil of the plant. is there. The distance between the center of one dense part and the center of the other dense part is 0.
It is formed to be 5 to 10 mm. The width of the sparse portion is formed to be 0.3 to 5.0 mm. The width of the sparse portion is formed to be always smaller than the interval between the dense portions. And in this embodiment, the sparse part is a non-woven fabric of 10 mm.
In the range of × 10 mm, 5 to 6 holes in the horizontal direction and 3 to 4 holes in the vertical direction are formed as holes of about 1.0 mm, and the basis weight of the nonwoven fabric 5 is 30 to 70 g / m 2.

If the width of the sparse portion is smaller than 0.3 mm, it will be difficult for shoots and roots of the plant to pass therethrough.
If it is larger than this, the soil and sand can easily pass through, and the effect of preventing suction by the nonwoven fabric is reduced. Here, when the sparse portion is formed as a hole portion and the width is relatively large (for example, 5.0 mm or more), it is considered that earth and sand slightly pass through the sparse portion. In such a case, if a thin thread is stretched over the sparse portion, the presence of the thread makes it more difficult for earth and sand to pass through. In other words, when the sparse portion is formed in a size that allows some amount of earth and sand to pass therethrough, if the sparse portion is disposed in the sparse portion, such as the thread-like body or the net-like body, the earth and sand cannot pass or pass through. If it is difficult to provide a state in which an obstructing member is provided that has the function of allowing the buds, roots, foliage, and foliage of the plant to pass through, earth and sand will be more difficult to pass through due to the presence of the obstructing member. Further, when the buds, roots, foliage and leaves of the plant are inserted into the sparse part, sediment hardly passes.

The mat 1 in which the above fibers are randomly entangled and the mesh-like nonwoven fabric 5 are, for example, an adhesive,
It is integrated by a ring gun or sewing. In this case, the mat 1 and the nonwoven fabric 5 are shifted in the extending direction by 5 to 10 cm to form a portion where the nonwoven fabric 5 is not attached to the mat 1 and a portion where the nonwoven fabric 5 is not bonded to the mat 1 (5 to 10 cm) ( (Not shown), and at the time of construction of the vegetation mat A for reinforced soil revetment, the joint portion of the mat 1 in which fibers are entangled at random is securely closed by the nonwoven fabric 5, and the mat 1
To prevent the earth and sand from being sucked out of the joint. In addition, the nonwoven fabric 5 may protrude in the vertical direction or at least below the mat 1 in which the fibers are randomly entangled, so that several layers of reinforced earth revetment are laminated to form the river revetment retaining wall 30. Is applied, it is possible to reinforce the laminated portion of each step where the suction is expected most, and to prevent the suction of the earth and sand from this portion. The overhang is 10 ~
Make it about 30cm.

Seeds, fertilizers, soil improving materials, water retention materials, and the like are mixed (vegetable base material 6) and adhered to the mesh-shaped nonwoven fabric 5 described above. Examples of the seeds include fescue such as tall fescue and creeping red fescue, so-called western turf seeds such as vermender grasses, bluegrass, and bentgrass, and native seeds such as mugwort and pampas grass, itachihagi, and yamahagi. Can be used according to the local situation. As fertilizers, fertilizers that dissolve early, such as chemical fertilizers, are also used.However, considering that they are sometimes submerged, resin-coated fertilizers that do not easily dissolve and flow out and microbial decomposition type fertilizers are more desirable, and these are appropriately used. It is also possible to use a mixture.

As the soil conditioner and water retention material, vermiculites such as vermulite, clay minerals such as bentonite, and organic substances such as bark compost, peat moss, and tree wool are used as appropriate.

In order to form the river embankment retaining wall 30 using the reinforced soil revetment vegetation mat A of the present invention, the river embankment retaining wall 30 is formed.
On the construction side, a retaining unit 2 having a rising portion 3 and a bottom portion 4 of an L-shaped net-shaped panel made of expanded metal or the like is arranged, and in a basic structure in which a geogrid 7 is connected to the bottom portion 4, a net-like rising portion 3 is formed. On the inside, the above-mentioned vegetation mat A for reinforced soil revetment is stuck, and then the soil is embanked 8 on the geogrid 7 of the bottom portion 4 and compacted. , The river revetment wall 30 is constructed. As shown in the drawing, the river embankment retaining wall 30 made of the reinforced earthwork is constructed by stacking surface net panels (rise portions 3) having a gradient of about 5 minutes at a vertical height of about 50 cm, and a geogrid on the bottom 4 of the L-shaped net panel. 7 is connected and attached, 1.0 to 1.5 m is laid on the embankment side, and the soil is embanked 8 on the upper part, and then compacted and compacted. Also,
In front of the backfill embankment 8, on the back side of the L-shaped net panel, stones such as natural stones and crushed stones are stuffed at positions below the river normal water level, and sheets for preventing suction are installed. Above the normal water level, the vegetation mat A for reinforced soil revetment of the present invention is attached to the back surface of the L-shaped net panel.

In the above description, the retaining unit 2 is described as an L-shaped net panel made of expanded metal. In addition, a reinforcing bar having a diameter of 4 to 6 mm is used.
A net-like body formed by welding in a grid pattern at a size of about 15 cm can be used after being formed into the same shape as the above-mentioned net panel.
The above-mentioned net panels and the like need to have strength and rigidity that do not appear due to the earth pressure of the soil embanked in the river bank protection wall 30.

The above-mentioned vegetation mat A for reinforced soil revetment of the present invention
When the river revetment retaining wall 30 is constructed by using this, the river revetment retaining wall 30 is submerged by the rising water of the river by the mat 1 and the mesh-like nonwoven fabric 5 on which the fibers constituting the vegetation mat A are randomly entangled. In this case, the flow velocity in the vicinity of the flowing water of the river is reduced, the suction of the soil in the river protection wall 30 by the flowing water of the river is prevented, and the plant seeds mounted on the vegetation mat A germinate. Mat 1 grown and randomly entangled with mesh-like nonwoven fabric 5 and fibers
The stems and leaves prosper in front of the river bank retaining wall 30, and the rhizome spreads in the soil of the embankment 8 in the river bank retaining wall 30 to bind the soil. As a result, even if the river revetment retaining wall 30 becomes submerged due to the rising water in the river, the flow velocity near the river flow is further reduced, and the effect of preventing the soil in the river revetment retaining wall 30 from being sucked out by the river flowing water is reduced. More certainty.

The second embodiment of the vegetation mat A for reinforced soil revetment of the present invention
In the embodiment, a durable net is used in place of the mat 1 in which fibers are randomly entangled in the configuration of the first embodiment described above. Is attached by other methods, and seeds and other fertilizers, soil improvement materials, water retention materials, and the like are further attached to the nonwoven fabric in the same manner as described above to form a reinforced soil revetment vegetation mat A ′.

The above-mentioned durable net is formed from a highly durable fiber, for example, a fiber such as nylon, polyester, aramid, carbon, glass, polyacetal or the like, and is formed into a lattice having a mesh size of 5 to 15 mm. However, by using the filaments of the above fibers, it may be braided into a mesh body having the same mesh as above, and these two may be overlapped, and the tensile strength per 1 m in width, 50-500
kg.

When the mesh-shaped nonwoven fabric 5 is mounted on the durable net, similarly to the first embodiment, the nonwoven fabric 5 may be displaced, for example, by about 10 cm in the extension direction of the vegetation mat A '. This prevents the soil in the river bank retaining wall 30 from being sucked out from the seam of the net. The overhang of the mesh-shaped nonwoven fabric 5 in the up-down direction can be performed in the same manner as in the first embodiment.

The vegetation mat A 'for reinforced soil revetment according to the second embodiment uses a more durable net than the vegetation mat A of the first embodiment. Since they can be put together and formed into a long length, the number of joints at the time of construction is small, the workability is improved, and the possibility of being sucked into the soil from the joints is extremely reduced. The other functions of preventing the suction of the soil in the river bank retaining wall 30, the disaster prevention function by greening the front surface of the river bank retaining wall 30, and the function of improving the landscape are the same as those in the first embodiment.

A fertilizer band 9 mainly containing a slow-release fertilizer is mounted along the extension direction near the top in the extension direction of the vegetation mats A and A 'for reinforcing soil embankment of the first and second embodiments. Sometimes. The fertilizer zone 9 is made of, for example, a fertilizer that dissolves early such as a chemical fertilizer in a band-shaped or tubular bag, or a resin-coated fertilizer that does not easily dissolve and flow out in consideration of sometimes being submerged. Fertilizers of the type are more desirable, and these are appropriately mixed and used. In addition, a water retention material such as vermukilite, bentonite, peat moss and the like and a soil improvement material may be appropriately mixed and stored together with the fertilizer. The material of the bag may be any material having a function of gradually dissolving and flowing out the fertilizer, for example, a nonwoven fabric such as polyester or vinylon, or a material obtained by laminating a net such as a kaya ground on hydrolyzed paper. Can be used. Considering the occasional submergence, a material having good durability such as polyester is more desirable. The size of the fertilizer zone 9 may be, for example, 2 to 5 cm in width and 1 to 3 cm in thickness.

By adopting this configuration, for example, in a reinforced earthwork unit stacked in two upper and lower layers, the rhizomes of the plants growing in the lower part of the upper part are replaced with the above-described reinforced soil revetment vegetation mats A, A in the upper part of the lower part. The fertilizer of the slow-release fertilizer zone 9 attached to the top of the 'grows in search of fertilizer, spreads near the upper and lower two-step boundary, tightens the soil near this, the river rises, and the reinforced earth method Even if the river revetment retaining wall 30 is submerged, it is possible to effectively prevent the soil in the river revetment retaining wall 30 from being sucked out. In particular, near the boundary between the upper and lower two steps, a geogrid material 7 is laid to stabilize the reinforced soil river embankment retaining wall 30, but the geogrid material 7 becomes a water supply and the river revetment retaining wall is laid. Although there was a case where the soil inside 30 could be sucked out, the above configuration can prevent it beforehand, and the stability of the river bank retaining wall 30 is further improved.

Although the present invention has been described above with respect to stabilization and landscape improvement by introducing vegetation in river revetments, the present invention is not limited to river revetment retaining walls, but can be applied to vegetation in general roads and residential land development. It can be applied to the retaining wall by the reinforced earth method to be introduced, and its effect can be fully exhibited.

[0031]

The present invention is a mat for reinforced soil revetment in a river revetment and a method for constructing the same, so that not only a river embankment with a river velocity of 2 m / s but also a river velocity of 4 to 5 m / s. It can withstand the expected river revetment retaining wall. The point to be especially noted is to prevent the scouring and cutting of the root system, which is a weak point of the introduced vegetation, by entanglement of the plant root system with a durable net or mesh-like non-woven fabric. It was possible to effectively prevent the suction of soil that had been embanked.

The effects of the present invention will be concretely described below. By using a durable net or a thick random mat located on the surface, the vegetation root system is entangled with the net to prevent vegetation loss due to fluid force and to reduce the surface flow velocity. Can be reduced. The mesh nonwoven fabric adhered to the back surface of the net or the like makes it possible to suppress the suction of the soil inside the river protection wall 30 together with the net. By installing a fertilizer zone using a water-insoluble slow-release fertilizer that has fertilizing effect for at least one year, the plant root system near the lower part of the vegetation mat constructed on the upper net panel part extends to the fertilizer zone part, The upper and lower joint portions that are easily scoured can be reinforced. In addition, fertilizer can be supplied to the lower part of the fertilizer zone, so that vegetation can be vigorously grown for a long period of time and the seawall can be protected.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory perspective view showing an embodiment of a working example of a reinforced earth revetment method according to the present invention.

[Explanation of symbols]

1 ... a mat with fibers randomly entangled, 2 ... a soil retaining unit, 5 ... a mesh nonwoven fabric, A ... a vegetation mat for reinforced soil revetment.

Claims (4)

[Claims] 1. A porosity of 85 to 9 having a thickness of about 5 to 20 mm.
A mesh nonwoven fabric capable of germinating and rooting is bonded to a mat in which about 5% of the foliage of the foliage of the plant foliage is randomly entangled, and the seed, fertilizer, soil improving material, and water retaining material are bonded to the nonwoven fabric. A vegetation mat for reinforced earth revetment characterized by attaching more than one species. 2. A durable net having a mesh size of 5 to 15 mm and a mesh nonwoven fabric capable of germinating and rooting are adhered, and the nonwoven fabric is attached with at least one of seed, fertilizer, soil improving material and water retention material. A vegetation mat for reinforced earth revetment, characterized by the following. 3. A vegetation mat for reinforced soil revetment, wherein a fertilizer band containing a slow-release fertilizer is mounted near the top in the extension direction of the vegetation mat for reinforced soil revetment according to claim 1 or 2. 4. A basic structure in which an earth retaining unit having an L-shaped rising portion and a bottom portion is disposed on the river bank retaining wall construction side, and a geogrid is connected to the bottom portion, wherein the inside of the rising portion is provided. Attach the vegetation mat for reinforced soil revetment described in 1, 2 or 3 and then fill the soil on the geogrid at the bottom and compact it. And constructing a wall for river revetment.