JP2893050B2 - Topsoil protection sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a topsoil protection sheet and, more particularly, to prevent soil erosion on bare lands or slopes caused by road construction, development of residential lands, agricultural lands, parks, and the like. It relates to a topsoil protection sheet that can be performed well.

[0002]

2. Description of the Related Art Conventionally, bare land caused by development, particularly,
For protection of slopes and the like, greening and the like have been performed by spraying a concrete structure or a medium seed mixture. But,
The former is not only expensive but also very artificial and inconvenient in terms of environmental protection and aesthetics, and is sometimes dangerous due to aging deterioration. Also, the latter, after construction, until the vegetation cover is completed, if soil erosion by rainwater is severe and strong rain is predicted, cover the entire surface with a waterproof sheet, and remove the waterproof sheet again after the rain has left. It is often repeated, cumbersome and expensive, and it is difficult to improve the vegetation rate. Furthermore, the shortage of specialized construction workers is becoming more serious, and in addition, damage to the sprayed surface and initial vegetation surface due to natural environmental conditions, birds, animals, flying objects, etc. cannot be ignored. Furthermore, it can be said that there has been no effective method for preventing erosion itself on the soil surface with sheets or mats other than waterproof sheets.

Therefore, in recent years, in order to prevent soil erosion due to the above-mentioned greening, a configuration in which various vegetation sheets (mats) are laid on the soil surface instead of the spraying method has been proposed. Examples of the sheet include mats, straws, and net composite products (for example, a composite product of a net and a jute, a palm, etc.).
And a thin sheet made of paper, a reinforcing net, a thin nonwoven fabric, or the like.

It is said that these vegetation sheets can prevent soil erosion by covering the soil surface and promoting the growth of the plant by setting the soil temperature to a favorable condition for the growth of the plant.

[0005]

However, the conventional vegetation sheet has the following problems. In other words, in the case of a thick sheet, due to the rigidity of the sheet and the nature of the material,
Since the sheet cannot fit the unevenness of the soil surface and the entanglement between the lower surface of the sheet and the soil is small, the boundary between the sheet and the soil is not integrated, and the flowing water flows under the sheet (in other words, under the sheet). For example, it flows along the boundary surface between the sheet and the soil), so that soil erosion is inevitable and greening is incomplete. In the case of a thin sheet using paper,
The strength and strength of the rain and the impact of strong rain are critically low, causing problems such as tearing, lifting and displacement, and almost no protection. There is no protection against soil and vegetation, and there is a possibility that soil structure destruction and germination / growth inhibition may occur. There are problems such as.

Meanwhile, a vegetation sheet using a thin cotton cloth integrated with seeds, fertilizers and the like has been considered as the vegetation sheet. This is an indispensable requirement that the thinness does not cause germination inhibition, and also the natural cotton cloth, the flexibility of the cotton cloth such as the non-woven cloth, and the close contact with the soil using the flattening at the time of the wetness are improved. In addition, while flattening due to wet or repeated wet and dry, a porous membrane is formed, rainwater flows down on the sheet surface, and greening is realized while protecting seeds, fertilizer and soil surface. Is what you do. In this case, the thickness of the cotton cloth is limited to a small thickness, and it is considered that the material is desirably a natural fiber or a cellulose-based regenerated fiber having relatively high water absorption and hydrophilicity.

Based on this viewpoint, the present inventor has conducted various studies on various types of thin sheets. As a result, although some vegetation was observed, the following serious problems may occur. found. That is,
The rainfall causes the cotton cloth to be wet and the fibers to be interfacially bonded to each other, thereby increasing entanglement between the fiber yarns, thereby inhibiting germination. Also, the entanglement between the soil and the sheet (non-woven fabric or cotton cloth) expected at the outset could not achieve a sufficient purpose because of the flattening due to wetting and the increase in entanglement between fibers. In some cases, floatation or void formation with the soil surface may occur. Non-woven fabric or cotton fabric is thin, and the thickness is further reduced by repeated drying and wetting.When exposed to strong direct sunlight, drying progresses rapidly and the topsoil surface becomes hot, not only hindering germination and rooting However, there are many parts that are severely affected by growth. When heavy rain continues and a large amount of rainwater flows or stays, the sheet will be uneven and dense, causing it to tear, and not only will the rainwater flow or stay on the sheet surface, but also the sheet will float, resulting in the soil surface Erosion occurs. When fibers with high water absorption and hydrophilicity are used, the growth of vegetation is not sufficient for soil protection due to the influence of natural conditions.
(4 months), the strength deteriorates, the strength decreases, it is difficult to withstand rainwater resistance due to heavy rainfall, and erosion frequently occurs.
When constructed from autumn to winter, the soil structure under the sheet was destroyed due to frost heave during winter, making it vulnerable to erosion. In addition, germination is inhibited due to flattening of the non-woven fabric during germination in early spring. The present invention has been made in view of the above points.
It is intended to be naked even in the wind and rain.
Topsoil protection without erosion of the topsoil and good vegetation
To provide a seat.

[0008]

The topsoil protective sheet of the present invention as a means for solving the above-mentioned problems is a sheet-like body formed by randomly entanglement of water-repellent fine fibers. As the aqueous fine fiber, a fine water-repellent fiber having a thickness of several deniers is used, and the sheet has flexibility, a thickness of 5 mm to 40 mm, and an apparent packing density of 2
At 4%, the sheet internal space forms a water channel in the plane direction, and has a medium composition for greening below the sheet. Further, the topsoil protection sheet of the present invention is characterized in that the fibers are fibers of irregular cross section.

Here, low hydrophilicity (or non-hydrophilicity),
The combination of low water absorption properties is called water repellency. And water repellent
Polyester fibers, other PP, P
E and PVC are preferable, and in addition, water-repellent
Natural cotton or rayon can be used. Also, the water repellent
The dendritic fiber has a thickness of several deniers (for example, 6 deniers).
And fine fibers like 2 denier)
Can improve the entanglement of the fibers,
It is possible to make the distribution of gaps uniform,
A sheet can be obtained, and water in the sheet can be obtained.
And the specific surface area in contact with soil and soil can be increased,
Good conduction of laminar flow through the inner space of thin sheets
Can form waterways and improve entanglement with soil.
It depends on what you can do. Also, as fiber
The use of water-repellent fine fibers was
This is the result of
In the case of a globular body, contact with runoff water and saturated soil water
Swarf occurs, and the internal space of the sheet-shaped body is lost,
While it is not possible to form a headrace channel in the direction of the plate,
In the case of a sheet made of fibers with water repellency,
No adhesion between fibers, no settling of sheet,
A space can be maintained and water can be contained in the internal space,
It is said that entanglement between the sheet and the soil can occur in the early stage of rainfall
Based on the reason. I used irregular cross-section fiber as the fiber
Increases its second moment of area, causing the fiber to flex.
To reduce the body, and to improve its resiliency
Under the natural environment such as rain,
The internal space of the sheet is sufficiently maintained for a long time.
Based on that. And the "irregular cross section fiber"
For example, using a hollow fiber cross section or a horseshoe-shaped cross section
Can be The thickness of the “sheet-like body” is 5 mm to
The value of 40 mm is a numerical value obtained by an experiment.
If it is less than 5 mm, the amount of rainwater under natural conditions
Water supply function is not performed, and
The flat sheet is flattened, and sufficient erosion is prevented.
It is not more than
If it is above, the water conduction function is fulfilled, in other words, the surrounding area
Depending on the environment, flattening is likely to be promoted, and
And there is no big difference, on the other hand, thickness of about 40mm
Even if there is a large amount of rainfall that is rarely seen for a long time
It turns out that it can be secured, on the other hand, if the thickness is more than this
Is the amount of sunlight irradiated to the soil surface in addition to processing and cost.
Is likely to be blocked. Also before
The apparent packing density is 2 to 4% (in other words, the porosity is 96%).
９８98%) because the maximum volume is assured with the minimum amount of fiber.
The ones that can keep the inside space of the sheet
Can be formed in the headrace channel and has good entanglement with the soil
It is based on considering that.

[0010]

As is apparent from the above description, the topsoil protective sheet of the present invention has the following effects.
Randomized water-repellent fine fibers with a thickness of several deniers
To form a so-called “wat-like” flexibility
Water inside the sheet.
Can be formed by laminar flow.
The erosion of the soil can be prevented. Further, the sheet-like body is made of the fine fiber.
A place where fibers are formed by randomly entangled fibers
Since it is made of a so-called “cotton” sheet, the sheet
The specific surface area that comes into contact with water and soil increases,
Fits irregularities, the lower surface of the sheet is well entangled with soil particles,
The adhesion between the sheet and the soil surface can be improved, and
The sheet and the soil surface are tightly integrated, and
The lifting of the sheet due to the impact can be prevented, and the sheet
Water required for vegetation in the greening medium composition object provided below
And oxygen supply, as well as the growth of effective microorganisms and
Other growth conditions can be maintained. Fine fibers with water repellency
Because of the use of fibers, elasticity due to contact with rainwater and other water
Of the sheet, that is, "slack" of the sheet,
The bulkiness of the sheet can be maintained between
Because it is rich in moisture and moisture retention and can prevent excessive drying,
Improve plant rooting. Sheet thickness is 5mm
~ 40mm, and the inner space of the sheet
When laid on the soil surface, rainwater
If sewage and soil saturated water can penetrate and guide the headrace
In both cases, water can flow in the plane direction through the headrace.
Therefore, the runoff water and soil saturated water run down the soil surface.
Can be prevented. Therefore, spillage of seeds and medium
Can be prevented, and a sufficient vegetation environment can be obtained.
Made of water-repellent fine fibers,
The separation resistance of the film between the fibers and water
To be able to smoothly flow water in the laminar flow state in the headrace
The greening medium composition below the sheet can be soiled.
Adhesion to the surface can be ensured. In the above invention,
Water-repellent with irregular cross-section as a fiber forming sheet
In the case of using fine fibers, the second moment of area
Raindrop impact due to rainwater because the section modulus can be increased
Also, the sheet-like body can withstand natural conditions such as
The bulkiness can be maintained and the inside of the sheet
Maintains a waterway in the plane formed by the space for a long time
And the effects of the invention can be further ensured.
This has the effect.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described.1 to 6
Shows an embodiment of the present invention,FIG.Of the topsoil protection sheet
Partial sectional view,FIG.Is a partial cross section of a state where a reinforcing net is provided.
Figure,FIG.Is a schematic side view of the test apparatus, and FIG. 4 shows test results.
Illustration of the state of the water flow,5 and 6 (a) and (b) show the book
It is explanatory drawing of the sheet | seat of this invention.

The topsoil protection sheet of the present embodiment has a
Topsoil protection sheet with soil erosion prevention and vegetation volume function
As shown in FIGS. 1, 5 and 6, the thickness is 5 to 4
Seed and medium composition on the lower surface of a fiber web 1 consisting of a 0 mm (most preferably 15 to 30 mm) mesh .
4 is made of a laminated sheet. Topsoil protection system in the form of Fig. 5
A reinforcing net is provided on the upper surface of the fiber web network 1.
3 on the lower surface of the fiber web network 1
And the medium composition 4 are laminated and integrated.
You. In this configuration, it can be used as a vegetation sheet.
The advantage is that the seeds can be
The body 1 protects against birds and wind and rain.
In addition, because it can fully contact the moisture in the soil, its growth
Can be improved. That is, by the reinforcing net,
In addition to protection from forces (animals and flying objects),
When fixed to the loam (wedge driving), the center of the topsoil protection body
Part of the fiber web mesh
The seeds and the medium composition 4 are deposited on the lower surface by the body 1.
Layer, but acts as a protective aquifer layer.
Disperses and moves the seed and the medium composition 4
Can be prevented. Fiber with a protective inner layer with a lot of internal space
Since it is a web network 1, it is necessary to supply and supply oxygen necessary for vegetation.
Of effective microorganisms and other vegetation conditions
It is also effective for protection. The fiber web network 1 has a thickness
Water retention due to high shape retention without flattening even when wet by hand
It is also rich in moisture and moisture and prevents excessive drying,
Has the advantage that it can improve
You. The topsoil protection sheet in the form shown in FIGS.
The fiber web, or the fiber web and reinforcement
Laminate the net and medium and / or seed layer to prevent germination
The medium and seed layer are not scattered or unevenly distributed without harm.
It is. By laying the sheet on the soil surface, integrated with the soil to form a guide path for inducing running water saturated soil water or the like, and hydration of the culture medium composition 4, the oxygen supply
This is performed sufficiently, and the outflow of the medium composition 4 by the water is prevented.
Stop soil erosion. Here, the reason why the thickness of the fiber web 1 is set to 5 mm to 40 mm is a numerical value obtained by an experiment. If the thickness is less than 5 mm, in the case of rainwater amount under natural conditions, a sufficient water guiding layer function is not performed. In addition, due to the falling pressure of the surface falling water, the bent fiber web is flattened, and sufficient erosion prevention is not achieved. In ordinary rainfall, a water guiding function is achieved if the length is about 5 mm or more. Flattening is likely to be promoted due to environmental conditions, and the concept of the “water guide layer” of the present invention is lost, and there is no large difference from the conventional product.
It has been found that even if it has a thickness of about m, it is possible to secure water conductivity even in the rare case of a large amount of long rainfall.
The above cases are taken into consideration in that, in addition to processing and cost, there is a high possibility of blocking the irradiation amount of sunlight on the soil surface. Here, in the fiber web 1, the fibers between the fibers keep a sufficient space and are entangled to keep a thick volume, and the fibers have low (or non) hydrophilicity and low water absorption (hereinafter, these properties are combined). This is a low-density random web made of a fibrous material having water repellency. In this embodiment, polyester fibers are used.
PE, PVC, or natural cotton or rayon that has been subjected to water repellency treatment may be used, and a mixture of these water repellent fibers and other fibers may be used within a range that does not cause settling and impair the water conduction function. Although it can be used, a web made of only non-water-repellent fibers such as natural cotton or rayon is not preferred. Here, the apparent packing density of the low-density random web used in this example is 2 to 4% (in other words, the porosity is 9%).
6-98%). The porosity of 96 to 98% was selected in consideration of the fact that the one having the minimum volume and the maximum volume could secure the maximum volume easily formed the water guide layer and improved the entanglement with the soil. It depends. The porosity enables the sheet to be sucked out and reduces the water flow in the soil. As a result, not only soil erosion but also soil collapse due to saturation can be further reduced. However, even with a porosity of 95% or less, such an effect can be obtained. Further, the water permeability was 0.5 to 10.0 (most preferably around 3.0). Incidentally, the measurement of the hydraulic conductivity was measured by the following method. That is, using the apparatus shown in FIG.
It was set to a size of 0 mm, and two sheets were piled up. This was laid directly in a water channel and saturated by water supply. At this time, whether or not the water was saturated was judged by a manometer and visual observation, and the water channel gradient was 5 °, 10 °. And 15 °, and the time when the dye water travels 30 cm is measured, and Darcy's law 1 k = v / i where k: water permeability (cm / s) v: dye The flow rate of water (cm / s) was determined by i: dynamic water gradient. The water flow rate at the time of saturation is measured, and Darcy's law is k = Q / (A × i) where k: water permeability (cm / s) Q: water flow (cm ² / s) A: sheet-like body Cross-sectional area (cm ² ) i: Determined by hydraulic coefficient. In the measurement of the amount of water flow, the amount of water flowing at a specific time was measured at a specific time by a measuring cylinder and converted to be obtained. As the polyester fiber, a modified cross-section yarn such as a hollow fiber cross section or a horseshoe cross section is used. This is due to the reduced flexibility of the random web.
More specifically, the fiber web 1 is spread on the topsoil surface 2 and fixed with an appropriate wedge such as a bamboo spine used for sowing, thereby preventing soil erosion. The fiber web 1 is formed of a random web, so that the soil enters the voids, the boundary surface between the fiber surface and the soil surface is lost, and the fiber water 1 is integrated with the soil water. By
The soil water is guided in the sheet to form a guide path for the soil water, thereby reducing soil erosion and structural destruction in the soil caused by the soil water.

Next, in order to confirm the effects of the above-described embodiment, results of running water analysis using the test apparatus shown in FIG. 3 will be described. First, masa soil as a soil sample was packed into a wooden open channel of the test apparatus to a thickness of 5 cm, and evenly compacted. Then, a partition was provided with a wire mesh so that the soil sample did not flow down, and the slope of the open channel was measured. Was set to 14.5 °, the fiber web 1 was spread on the soil surface, and water was allowed to flow from the upper end portion to check the state of flowing water. In addition, a similar test was also performed on a bare ground where the fiber web 1 was not developed, and the two were compared. Then, results as shown in Table 1, Table 2, and FIG. 4 were obtained.

[0014]

[Table 1]

Here, fiber web: polyester 6d rayon 2d: binder: 45/45/10, basis weight 30 g / mE2, thickness 5 mm, flow water flow rate: 70
ml / s, channel gradient: 10 °.

[0016]

[Table 2]

Here, from the result of the flow water amount: 70 ml / s or more, in the case of this embodiment, the fiber web 1
Works as a protective water-conducting layer, has low water permeability resistance, and it can be confirmed that most of the flowing water is guided to the mesh layer and flows down in the mesh layer. At this time, it is possible to achieve an extremely effective erosion prevention by taking a sufficient thickness to allow the flowing down water to flow. Further, the thick low-density reticulated body 1 first absorbs the impact of raindrops to move soil particles. However, it was confirmed that the flexibility of the low-density reticulated body 1 fits the unevenness of the ground 2 and the lower end is entangled with the soil particles. Further, the flowing water has a large resistance in the boundary surface where the entanglement of the soil particles and the fibers has occurred and in the saturated water, so that the flowing water is naturally guided to the reticulated body and flows down in the reticulated space. That is, it was confirmed that erosion was avoided because the cross section of the mesh body 1 served as a headrace channel and did not flow down the soil surface.

As described above, the function of the water guiding layer is ensured by the fact that the shape (flexibility) of the sheet (net-like body) does not greatly change and is not flattened not only by flooding but also by repeated wetting and drying. It is considered that there is. In addition, when the temporal change was confirmed outdoors, it was confirmed that the fixed topsoil had extremely high erosion resistance against wind and rain, and also that strong direct sunlight and temperature that caused soil destruction were observed. The fiber web 1 acts as a buffer layer against repetition of change, wind damage, drying, and drying and wetting, so that an extremely stable soil structure can be maintained, and soil destruction due to so-called frost collapse in winter is also possible. It has been confirmed that the fiber web 1 acts extremely effectively when used as a buffer material against the outside air.

It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications that can be made without departing from the gist of the present invention. Incidentally, shown in FIG.
The reinforcing net 3 on the upper surface of the fiber web
Is desirably provided by bonding or the like. For this configuration
In the case, for example, after the production of the fiber web, the reinforcing net 3
May be bonded (adhesive, thermal bonding, etc.)
Preferably, an adhesive function should be added when fabricating the fiber web.
Using the given reinforcing net 3 as a base material, fibers are blown on it.
By skipping and accumulating uniformly, the reinforcing net 3
It is good to have an integrated fiber web. Also,
Fiber forming a fiber web by the reinforcing net 3
Eliminates the risk of birds and flying objects catching and scattering
Not only has the advantage of being able to
By fixing the end face, the center of the seat rises
On the other hand, the sheet (fiber web)
B) to prevent the extension of
There is also an advantage of ensuring uniformity in the process.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a topsoil protection sheet showing one embodiment of the present invention.

FIG. 2 is a partial sectional view showing a state in which a reinforcing net is provided.

FIG. 3 is a schematic side view of a test apparatus.

FIG. 4 is an explanatory diagram of a state of a water flow showing test results.

FIG. 5 is an explanatory diagram of a sheet according to the present invention .

FIG. 6 is an explanatory diagram of a sheet according to the present invention .

[Explanation of symbols]

1 ... fiber web mesh, 2 ... ground, 3
..Reinforcing nets, 4 ... seed and medium composition, 5 ...
Water-soluble film layer, 6 ... Cotton backing layer, 7 ... Reinforcing net, 8 ... Heat sealing

Continuation of front page (56) References JP-A-52-59905 (JP, A) JP-A-55-162902 (JP, A) JP-A-57-81512 (JP, A) JP-A-58-20812 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) E02D 17/20 102 E02D 17/20 103

Claims (2)

(57) [Claims] 1. A sheet-like body formed by randomly entanglement of water-repellent fine fibers, wherein the water-repellent fine fibers are:
Using fine water-repellent fiber having a thickness of several deniers, the sheet has flexibility, a thickness of 5 mm to 40 mm, an apparent packing density of 2 to 4%, and an inner space of the sheet in a plane direction. A topsoil protection sheet, wherein a waterway is formed, and a greenery medium composition object is provided below the sheet. 2. The topsoil protection sheet according to claim 1, wherein the fibers are fibers having a modified cross section.