JP2001254331A - Erosion prevention sheet and ground surface erosion prevention method using the sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent erosion of the ground surface inundated during a flood or the like on the face of slope of levee of river or the like. SOLUTION: To the front and rear surfaces of the union cloth portions respectively inside the wale texture 23 of thermoplastic resin monofilament having the wire diameter of 0.1 to 0.8 mm, a high shrinkage thermoplastic resin thread is woven as a needle thread at the predetermined intervals along one direction of the ground weave 23. Each intersection of the ground weave 23 after heat treatment is melted to one united body and, by the needle thread 24 which become a chord shape on the front and rear surfaces of the ground weave 23 by thermal shrinkage, a continuous wavy sheet having the height of waveform of not more than 30 mm with the union cross portion being located at least to the crest portion or the valley portion and the percent of voids of the space portion designated by the outer profile is not less than 90%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet for preventing erosion and a method for preventing erosion of the ground surface by using the sheet. In particular, the sheet for preventing erosion made of a three-dimensional structure cloth on the surface of a slope such as a river embankment is used in the direction of river flow. The present invention relates to a method for preventing erosion of a ground surface which is laid from a shoreline to a high water level along the shore so that erosion of a submerged ground surface can be reliably prevented in a flood or the like.

[0002]

2. Description of the Related Art Conventionally, as a slope protection method for preventing erosion of a slope on a river embankment, a method of protecting a bank having a nonwoven fabric laid along the slope has been proposed (JP-A-6-103).
No. 24). In this protection method, a sheet of nonwoven fabric having a fiber density of 10 to 2000 m / cm ³ is laid on the soil surface of the embankment. Then, a soil of a predetermined thickness is constructed on the nonwoven fabric sheet, and vegetation is performed by sowing or pasting plants such as grass. When the plant roots penetrate through the non-woven fabric layer and extend inside the embankment earth and sand, the non-woven fabric and the embankment surface ground are integrated, and the soil erosion by the flow of the river can be resisted.

[0003]

[Problems to be Solved by the Invention] (Functional conditions required as an erosion prevention sheet) By the way, in order for the laid sheet to sufficiently perform the erosion prevention function, the sheet is prevented from being turned up against the river water flow. In addition, it is required that the earth surface is prevented from being sucked out.

That is, when an erosion prevention sheet is laid and a plant grows, roots of the plant penetrate the sheet and are stretched in the ground, so that the plant and the sheet exposed to running water flip up. It is necessary to make it hard to be washed away. In addition, it is necessary to prevent soil and sand on the ground from being washed away through the mesh of the sheet.

In view of the above-mentioned protection method using a nonwoven fabric from the viewpoint of achieving these functions, it is necessary to reduce the fiber density of the nonwoven fabric and increase the void diameter in order to prevent the nonwoven fabric from turning over. However, in this case, the effect of preventing suction is reduced. As described above, in the case of the above-mentioned nonwoven fabric sheet, the function of preventing the sheet from being turned up and the function of preventing the suction can not be achieved at the same time.

Further, in an erosion prevention sheet laid for the purpose of preventing erosion of the ground surface against river water flow,
It is preferable that a tractive force reduction function is provided in a state where it is submerged in the flow of the river. Here, the tractive force refers to a force acting to move the grains of the earth and sand on the ground surface when flowing water flows on the ground surface, and increases as the flow velocity increases. When this sweeping force exceeds a certain level, the earth and sand starts to move. Therefore, by laying a sheet on the ground surface, reducing the flow velocity of the running water flowing on the ground surface to reduce the tractive force, and suppressing the movement of sediment in and under the sheet, the soil is exposed to the running water. It is desirable to prevent spills.

As described above, various sheets are used as erosion prevention sheets in such a manner that they have a shape that is easy to handle at the time of construction, and that the shape can be sufficiently maintained at the time of construction. In order to ensure that the space held by the sheet is filled with earth and sand efficiently and reliably, and to maintain sufficient durability in the future, the wire diameter of the fibrous material constituting the sheet, It is important to satisfy various conditions such as the thickness of the sheet and the porosity so that the space in the sheet can be filled with an appropriate amount of earth and sand. Applicants
A part of the research results advanced from these viewpoints is disclosed as an erosion preventing sheet mat in JP-A-10-317352 (Japanese Patent No. 2963987).

(Problems in Application of Ready-made Sheets) By the way, there are also ready-made sheet mats which meet the above-mentioned functional requirements to some extent as the erosion preventing sheet. Is the workability,
There are many points to be improved, such as required strength and durability after laying.

[0009] For example, as a ready-made sheet having the above-mentioned qualitative requirements as an erosion prevention sheet, there is a three-dimensional structure cloth in which a woven fabric of a thermoplastic monofilament is continuously corrugated (see Japanese Patent Application Laid-Open No. Hei 8-226045). . This kind of three-dimensional structure cloth (hereinafter referred to as a continuous wave sheet)
In the Japanese Patent Application Laid-Open No. H11-229, a high-shrink yarn is disposed on the front and back surfaces of the ground structure, and the high-shrink yarn is subjected to a dry heat-limited shrink treatment (130 ° C.) to form a thermoplastic resin monofilament woven fabric in a continuous wave shape.

However, in this conventional continuous wave sheet,
Since only the ground structure is forcibly curved by the shrinkage of the high shrinkage yarn, the fabric of the resin monofilament constituting the ground structure is easily distorted. When this continuous corrugated sheet is used as the above-described erosion prevention sheet, it cannot resist the surface pressure at the time of earth and sand compaction covering the surface at the time of laying the sheet, the wave shape is deformed, and a predetermined amount of earth and sand can be filled. Absent. In addition, a monofilament having a relatively high rigidity is used, the texture of the monofilament is coarse, and the ground structure intersection is not fused. For this reason, the end of the monofilament fabric is likely to be frayed on the cut surface of the sheet, and the handling during construction,
There is a problem in terms of durability when laid on the ground and vegetated.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional sheet, to provide a condition as a sheet for preventing erosion, to facilitate handling during construction,
Rich in deformation resistance (compression resistance), and has a sufficient sweeping force reduction function after laying, can prevent the sheet from turning up and sucking out earth and sand even when exposed to running water, and has excellent durability It is another object of the present invention to provide a sheet for preventing erosion and a method for preventing ground surface erosion using the sheet.

[0012]

Means for Solving the Problems To achieve the above-mentioned object, the present invention relates to a method of forming a thermoplastic resin monofilament having a wire diameter of 0.1 to 0.8 mm on each of front and back surfaces of a cross-woven portion in a woven fabric structure. A high-shrinkable thermoplastic resin yarn is woven as a tension yarn at predetermined intervals along one direction of the ground structure, and each intersection of the ground structure after heat treatment is fused and integrated, and The continuous yarn is formed into a continuous wave-like sheet having a wavy height of 30 mm or less such that the interwoven portion becomes at least a peak or a valley by the shrinking yarn that has shrunk to form a chord on the front and back surfaces of the ground structure. The porosity of the space defined by the outer contour is 90% or more.

At this time, it is preferable that the rate of reduction in the thickness direction of the continuous wave sheet is 40% or less for a surface load of about 1800 N / m ² .

It is preferable that, in addition to the above-mentioned tensions stretched in a chord on the front and back surfaces of the ground structure, a high-shrinkable thermoplastic resin yarn is continuously arranged as an intermediate tension at an intermediate position of the continuous wavy portion.

The above-mentioned erosion preventing sheet is fixed on a shaped ground via a fixing tool, and the continuous corrugated portion is filled with earth and sand to cover the entire erosion preventing sheet and laid on the ground. It is characterized by the following.

Further, the erosion prevention sheet is laid on the river side slope of the embankment, a soil layer is formed on the continuous wavy portion, and vegetation is performed on the soil layer to form the erosion prevention sheet. A part of the roots of the vegetation is made to take root in the ground through the weave of the sheet.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the erosion preventing sheet of the present invention and a method for preventing ground surface erosion using the sheet will be described below with reference to the accompanying drawings. Figure 1 shows embankment 1
Shows the state immediately after the erosion prevention sheet 10 is laid on the slope 2 on the river side. The erosion prevention sheet 10 is a synthetic fiber woven sheet having a three-dimensional structure having a continuous corrugated cross section (see FIG. 3). The erosion prevention sheet 10 is provided with a predetermined overlapping margin 10a above the shoreline from the upstream side of the river,
10b is fixed to the ground slope 2 by a retaining pile (not shown). In FIG. 1, two rows of upper and lower erosion prevention sheets 10 are laid along the slope 2, and the laying range is such that the shoreline W is laid even when the water level is high. It is preferable to set so as not to exceed the position. A soil (not shown) having a predetermined thickness is used for vegetation on the surface on which the erosion prevention sheet 10 is laid, and the erosion prevention sheet 10 becomes invisible when the slope work is completed.

FIG. 2 is a state explanatory view showing a high water level state caused by rainfall or the like after completion. As shown in the figure, reeds, reeds and the like as waterside plants 4 grow near the shoreline W of the embankment 1, and shiba as terrestrial plants 5 grow on the land portion so as to cover the entire embankment. ing. In this state, for example, when there is heavy rain, the amount of flowing water in the river increases, and the erosion proceeds so that the flowing water having a high flow velocity removes the overburden portion (soil) 8 covering the erosion prevention sheet 10.

At this time, since the plants 4 and 5 growing near the shoreline W have their roots (not shown) stretched in the ground at the bottom of the water, they have high erosion resistance to running water flowing near the shore. . In the vicinity of the shoreline W of the embankment 1, erosion is likely to occur repeatedly due to an increase or decrease in the amount of water. For this reason,
As a preceding plant species used for vegetation, it can resist frequent fluctuations in water level, stabilize the soil by growing,
Those having high adaptability to the surrounding environment are preferable.

Here, a continuous corrugated sheet applicable to the above-mentioned erosion prevention sheet 10 (hereinafter denoted by reference numeral 10).
Will be described with reference to FIGS. FIG. 3 shows a continuous corrugated sheet 10 in which a part of a flat interwoven fabric 10T (FIGS. 4 and 5A) is processed to have a continuous waveform. A monofilament of polypropylene as a thermoplastic resin is used for the yarn of the interwoven fabric 10T shown in FIG. In the present embodiment, each monofilament is an integral yarn of a high melting point polypropylene (softening point of 160 ° C.) as a core and a low melting point polypropylene as a jacket.
It has a softening point of 50 ° C., and the surface partially softens and melts at this ambient temperature.

The wire diameter of the polypropylene monofilament is preferably from 0.1 mm to 0.8 mm. Wire diameter is 0.1mm
Since the ground texture woven with less than one has low rigidity of the monofilament itself, it has insufficient bending strength, and it is difficult to maintain the shape required for the erosion prevention sheet.
If it exceeds 0.8 mm, the fusion portion at the intersection of the yarns of the woven fabric will be small, and the fusion strength at the intersection may be insufficient. A fineness of 70 to 4600 dtex in the monofilament corresponds to the above wire diameter.

The texture of the mixed woven fabric 10T is 0.5 to
A 20 mm fabric can be applied. If the mesh is less than 0.5 mm, the filling of the earth and sand through the mesh of the fabric cannot be sufficiently performed. On the other hand, if the mesh size is 20 mm or more, sufficient rigidity of the entire sheet cannot be ensured even when the intersections of the yarns of the woven fabric (monofilaments in the present embodiment) are fused as described later.

Hereinafter, the woven structure will be described with reference to FIGS. 4 and 5A. The interwoven fabric 10T has a ground structure 23 made of the above-described polypropylene monofilament fabric.
And a weaving section 25a plain-woven at a predetermined interval from the ground structure 23 in the vertical direction.
Further, a polyester twisted yarn (softening point 240 ° C.) as a tension yarn 24 of a highly shrinkable thermoplastic resin yarn is woven into the interwoven portion 25a at a predetermined interval. This polyester twisted yarn is obtained by bundling element yarns into one, and the high-shrinkable thermoplastic resin tension yarn 24 is an intermediate floating yarn in the floating portion 25b.

Further, this interwoven fabric 10T (FIGS. 4 and 5)
By performing the dry heat limited shrinkage treatment (150 ° C.) on (a)), a continuous corrugated sheet 10 having a continuous corrugated portion 25 as shown in FIGS. 3 and 5B is formed.

That is, when the dry-woven fabric 10T is subjected to the above-mentioned dry heat limited shrinkage treatment, the high shrinkable thermoplastic resin tension yarn 24 becomes
It contracts in the longitudinal direction by a predetermined contraction rate (45 to 50%) without softening. At this time, since the tension yarns 24 are woven into the adjacent interwoven portions 25a so as to be alternated on the front and back surfaces of the ground texture, the tension yarns 24 have a chord shape so as to draw between the adjacent interwoven portions 25a, and the ground texture 23 has a continuous waveform. The sheet is bent to form a continuous wave sheet as a whole. At this time, at the intersections of the polypropylene monofilament woven fabric having the ground structure 23 curved in a continuous wave shape, only the low-melting-point polypropylene jacket described above softens and melts and fuses with each other as a result of the thermal action. The core does not soften and retains its original rigidity. As described above, the bending action due to the contraction of the tension yarn 24 and the respective intersections of the continuous wave-shaped ground structure formed by the bending action are simultaneously fused, so that a predetermined sheet thickness corresponding to the waveform can be secured, and the sheet can be secured. The continuous wave sheet 10 having the increased rigidity in the surface direction is manufactured.

A single monofilament fabric may be used as long as the fiber surface corresponding to the jacket can be melted and subjected to intersection fusion by heat treatment in a predetermined low-temperature atmosphere (145 to 150 ° C.). In addition to the above-mentioned polypropylene, polyethylene, olefin-based resin, polyester-based resin, polyamide-based resin, and the like can be used as the resin.

This kind of continuous wavy sheet 10 is carried to the site in the form of a roll or the like, and cut into an appropriate length suitable for the site, and is used. Because it is fused, no matter where you cut it, the yarn will not fray. Therefore, there is no waste of material at the time of cutting or the like. In addition, the sheet is laid on the ground as an erosion prevention sheet, so that when the vegetation grows, the eyesight does not collapse and the durability is excellent.

The shape and dimensions of the continuous corrugated sheet 10 are preferably 50 mm or less in consideration of the workability at the time of laying and the filling property of the earth and sand filled in the continuous corrugated valley of the sheet. In particular, in consideration of the rigidity with respect to the surface load applied to the sheet, it is preferable that the waveform height is 30 mm. As for the waveform pitch, it is preferable that the aspect ratio with respect to the waveform height is small and dense as long as the predetermined earth and sand filling property can be ensured. This waveform height corresponds to the sheet thickness. Therefore,
The sheet thickness of the continuous wave sheet 10 is particularly preferably 30 mm or less.

Next, the porosity of the continuous wave sheet 10 will be described. The continuous wave sheet 10 has a wave shape in which the peaks and valleys on the front and back surfaces are respectively continuous at a predetermined interval (corresponding to the wave pitch). In such a sheet, the wave height of the wave shape is reduced. The ratio of the space portion excluding the volume of the fibers constituting the sheet to the unit volume divided by the outer contour of the entire sheet when considered as the sheet thickness can be defined as the porosity. That is, the porosity can be expressed as a general formula as shown below.

Porosity = (1−sheet mass / Σ (fiber volume / density)) × 100 (%) (formula 1) where, sheet mass: mass per unit area of sheet with uniform sheet thickness (g) Fiber Volume: Volume of each constituent fiber (cm ³ ) Density: Density of each constituent fiber (g / cm ³ ) In Formula 1, the fiber volume is calculated for each of the polypropylene monofilament as the constituent fiber and the twisted polyester yarn, and the continuous as a composite material The porosity of the corrugated sheet can be determined.

In the continuous wave sheet of the present invention, the lower limit of the porosity was set to 90%. For example, when the porosity is less than 90%, when used as a sheet for preventing erosion, a space for filling with earth and sand cannot be secured. In addition, there is a possibility that roots of the plant at the time of vegetation may hinder the penetration of the sheet to take root on the ground. In particular, the porosity is preferably 90% or more in order to reliably fill the earth and sand having different particle sizes during construction.

Further, when the continuous wave sheet is used as a sheet for preventing erosion, it is necessary to consider compression resistance against a surface load applied to the sheet. For example, in the present invention, this load is assumed to be the load of an earth and sand compaction construction device used when the continuous wavy valley of the sheet is filled with earth and sand when the sheet is laid. Under these assumed conditions, the compressive deformation in the surface direction of the sheet in a state where a surface load of about 1800 N / m ² was applied to the sheet was evaluated as a reduction rate with respect to the original thickness. For example, when used as an erosion prevention sheet, a sheet having a compression reduction ratio of 40% or more is not preferable because the earth and sand filling amount is too low.

FIGS. 6 to 8 are explanatory views showing another embodiment of the continuous corrugated sheet 10 for the sheet for preventing erosion according to the present invention. In this continuous wave sheet 10, FIGS.
As shown in (b), an intermediate tension yarn 26 is arranged in addition to the tension yarn 24 for forming the corrugated shape. This intermediate yarn is also made of a yarn of the same material as the high shrinkable thermoplastic resin tension yarn 24, and is disposed substantially at the center of the height of the waveform when the continuous wave sheet 10 forms a waveform. By arranging the intermediate tension yarn 26, the erosion prevention sheet 10
In addition to its own in-plane stiffness, an additional tensile material that resists the tensile direction is arranged to maintain the curved shape, so that when the erosion prevention sheet 10 is embedded in the soil, In addition to increasing the resistance, the filled soil can be prevented from flowing out due to the flow of rivers and the like.

[0034]

EXAMPLES The compression resistance of the sheet according to each of the following examples is compared with a comparative example. [Configuration of Erosion Prevention Sheet] (Example 1) Ground structure: polypropylene monofilament (fineness 176)
0dtex) woven fabric (weft density 10 yarns / inch, warp density 1)
High shrinkage yarn: polyester twisted yarn (fineness: 1100 dtex) Thermal shrinkage 45-50%, 18 yarns / inch (9 on each side) Floating part width: 4 cm Dry heat limited shrinkage treatment condition: 145- 150 ° C. dry heat for 1 minute, 45% width setting processing Continuous waveform shape dimensions: waveform height × wave pitch = 3 cm × 4 cm (Example 2) Ground structure: polypropylene monofilament (fineness 110
0dtex) woven fabric (weft density 25 yarns / inch, warp density 7)
High shrinkage yarn: Polyester twist yarn (fineness: 1100 dtex) Thermal shrinkage 45-50%, 9 yarns / inch Floating part width: 4 cm Dry heat limited shrinkage treatment condition: 145-150 ° C Dry heat 1 minute, 45% Width setting processing Continuous waveform shape dimensions: waveform height × wave pitch = 3 cm × 4 cm (Example 3) Ground structure: polypropylene monofilament (fineness 176)
0dtex) woven fabric (weft density 10 yarns / inch, warp density 1)
High shrinkage yarn: polyester twisted yarn (fineness: 1100 dtex) Heat shrinkage 45-50%, 18 yarns / inch (front and back, middle position in two stages) Floating fabric part width: 4 cm Dry heat limited shrinkage treatment conditions: 145-150 ° C dry heat for 1 minute, 45% width setting processing Continuous waveform shape dimensions: waveform height x wave pitch = 3 cm x 4 cm (comparative example)
0dtex) woven fabric (weft density 25 yarns / inch, warp density 7)
High shrinkage yarn: Copolymerized polyethylene terephthalate multi-yarn (fineness: 1100 dtex) Heat shrinkage 45-50%, 2.5 yarns / inch Floating part width: 4 cm Dry heat limited shrinkage treatment condition: 130 ° C dry Heat 3 minutes, 45% width setting processing Continuous waveform shape dimensions: waveform height x wave pitch = 3 cm x 4 cm [Softening point of used fiber] (Examples 1 to 3) Polypropylene monofilament core softening point 160 ° C, softening of jacket Point 145 to 150 ° C (Comparative example) Polypropylene monofilament
Softening point 160 ℃

[Compression Resistance Test] (Test Method) A surface load of 1800 N / m ² is continuously applied to the sheet surface for 1 minute. The amount of deformation of the sheet in the plane direction in the loaded state is measured, and the compression reduction rate with respect to the original thickness is calculated. (Evaluation of test result) A compression reduction rate of 40% or less is regarded as conformity. (Test results) The results of the above tests are shown in Table 1.

[Table 1]

In Table 1, the porosity is a value calculated from the above (Equation 1). In addition, the evaluation in the table indicates whether or not the sheet is suitable for the compression resistance required as the erosion prevention sheet.

[Construction of Erosion Prevention Sheet] Here, FIG.
9 is laid on the embankment slope as the erosion prevention sheet 10 to prevent erosion of the ground surface of the continuous corrugated sheet 10 shown in FIG. Will be explained. Roll-shaped erosion prevention sheet 1 pressed against ground surface 2a shaped to a predetermined slope
0 is laid while unrolling from the river upstream (Fig. 9
(A)). A roll having a width of 1 to 2 m and a length of several tens of meters is suitable for production, transportation and construction. At this time, the slope 2 shown in FIG. 1 can be assumed as an example, but in each of FIGS. 9A and 9B, only the slope is shown in an enlarged manner. In order to prevent the sheet laid on the slope from falling off in parallel with the sheet laying, the entire erosion prevention sheet 10 is fixed to the ground surface 2a using the fixing pile 40 as a fixture (FIG. 9).
(B)). As the retaining pile 40, a steel pile is used.

The continuous corrugated portion of the erosion prevention sheet 10 is filled with earth and sand 7 (see FIG. 9C). Sheet 10
It is preferable that the sand 7 is sufficiently filled in the corrugated mountain portion by a spraying machine or the like. It is preferable to use a viscous soil containing a large amount of organic matter to be used as a fertilizer, because the soil 7 easily stays inside the sheet. At the time of filling, part of the earth and sand 7 may be accumulated in the valley.

Next, the soil 8 is applied to cover the entire erosion prevention sheet 10 (see FIG. 9D). As a soil material covering the erosion prevention sheet 10, a mixture of seeds of vegetation plants 4 and 5 selected from a mixture of a plant growth base material such as bark compost and peat moss and an appropriate fertilizer is used. .
This soil material is also sprayed with a predetermined thickness (1 to 5c).
It is preferable to provide the m) of the soil layer. Further, if necessary, cutout holes (not shown) may be provided at predetermined intervals on the surface of the erosion prevention sheet 10, and an appropriate vegetative precursor plant species may be planted in the cutout holes.

FIG. 9E shows that the plant 4 grows and its root 4a
It is the schematic which showed the state which penetrated the mesh of the erosion prevention sheet 10, and was stretched to the ground depth of the lower side. As shown in the figure, the root 4a of the plant 4 integrates the soil 8, the erosion prevention sheet 10, and the ground.

FIG. 10 is a schematic diagram showing a state in which the river water level has risen to a range where the erosion prevention sheet 10 has been laid by rainfall or the like after the plant 4 has grown to some extent (for example, see FIG. 2). The figure shows a curve schematically showing the flow velocity distribution of the flowing water at this time. The running water receives resistance due to contact friction with the ground surface 2a near the bottom of the water,
The flow velocity decreases. At this time, the earth and sand on the ground surface 2a is washed out by a certain amount of sweeping force. When the earth and sand (the soil 8) deposited on the sheet is removed, the surface 10c of the erosion prevention sheet 10 is exposed, and the exposed thickness of the sheet 10 increases as the erosion progresses.

As shown in FIG. 11, the erosion prevention sheet 1
When the zero wavy portion 25 is exposed, the flow velocity of the flowing water rapidly decreases due to the contact friction with the sheet surface 10c. As a result, the tractive force is reduced and the erosion rate is also reduced. For this reason, the root 4a of the plant 4 is not pulled out, so that the erosion resistance of the plant 4 can be reliably contributed to prevention of erosion on the slope.

[0044]

As described above, according to the present invention,
It is easy to handle during construction, has deformation resistance,
In addition, after laying, it has a sufficient sweeping force reducing function, and can prevent the sheet from turning up and sucking out earth and sand even when exposed to running water, and has an effect that an erosion prevention structure having excellent durability can be constructed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a state in which an erosion prevention sheet of the present invention is laid on a slope of a river embankment.

FIG. 2 is a state explanatory view showing a state in which the erosion prevention sheet surface shown in FIG. 1 is exposed at a high water level.

FIG. 3 is a partial perspective view showing one embodiment of a continuous corrugated erosion prevention sheet according to the present invention.

FIG. 4 is a partial perspective view showing a cross-woven fabric used to form the continuous corrugated erosion prevention sheet shown in FIG. 3;

FIG. 5 is a schematic cross-sectional view schematically showing the erosion preventing sheet shown in FIGS. 3 and 4 and the interwoven fabric used therein.

FIG. 6 is a partial perspective view showing another embodiment of the continuous corrugated erosion prevention sheet according to the present invention.

7 is a partial perspective view showing the interwoven fabric used to form the continuous corrugated erosion prevention sheet shown in FIG. 6;

FIG. 8 is a schematic sectional view schematically showing the erosion preventing sheet shown in FIGS. 6 and 7 and the interwoven fabric used therein.

FIG. 9 is a construction state explanatory view showing a construction procedure of laying the erosion prevention sheet shown in FIG. 3 on a slope.

FIG. 10 is a partially enlarged view showing a flow velocity distribution near a river bottom at a high water level.

11 is a partially enlarged view showing a state in which erosion of the riverbed has progressed from the state shown in FIG. 10 and an erosion prevention sheet has been exposed;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Embankment 2 Slope 10 Erosion prevention sheet (continuous wavy sheet) 23 Textile 24 Tension yarn 25 Continuous wavy part 26 Intermediate tension yarn

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Atsushi Hattori 1 Asahi, Oaza, Tsukuba, Ibaraki Prefecture Within the Public Works Research Institute, Ministry of Construction (72) Inventor Kanshiro Hoki 32-12-1 Higashiyama, Meguro-ku, Tokyo Taiyo Kogyo (72) Inventor Takayuki Masoo 3-22-1, Higashiyama, Meguro-ku, Tokyo Taiyo Kogyo Co., Ltd. (72) Inventor Takanobu Sugiyama 3-2-1-1, Higashiyama, Meguro-ku, Tokyo Taiyo Kogyo Co., Ltd. F term in the company (reference) 2D018 DA03 2D044 DA12 DB04

Claims (5)

[Claims] (1) A highly shrinkable thermoplastic resin yarn is formed as a tension yarn on each of the front and back surfaces of the interwoven portion in a woven fabric structure of a thermoplastic resin monofilament having a wire diameter of 0.1 to 0.8 mm. Each of the intersections of the ground structure after the heat treatment is fused and integrated at a predetermined interval along the direction, and is heat-shrinked to form a chord on the front and back surfaces of the ground structure. The yarn is formed into a continuous wave-shaped sheet having a wavy height of 30 mm or less such that the interwoven portion is at least a peak or a valley, and the void ratio defined by the outer contour of the continuous wave-shaped sheet is 90% or more. A sheet for preventing erosion, characterized in that: 2. The erosion prevention sheet according to claim 1, wherein the continuous wave sheet has a compression reduction rate in the thickness direction of 40% or less with respect to a surface load of about 1800 N / m ² . 3. A high-shrinkable thermoplastic resin yarn is continuously arranged as an intermediate yarn at an intermediate position of the continuous wavy portion, in addition to the yarns stretched chordally on the front and back surfaces of the ground structure. The erosion prevention sheet according to claim 1 or 2, characterized in that: 4. The sheet for preventing erosion according to any one of claims 1 to 3 is fixed on a shaped ground via a fixing tool, and the continuous corrugated portion is filled with earth and sand. A method for preventing ground surface erosion using an erosion prevention sheet, wherein the entire erosion prevention sheet is covered and laid on the ground. 5. The erosion prevention sheet according to any one of claims 1 to 3, which is laid on a river-side slope of the embankment, and a soil layer is formed on the continuous wavy portion. A ground surface formed by the erosion prevention sheet, wherein vegetation is performed on the soil layer, and a part of the root of the vegetation is made to survive in the ground through the weaving of the erosion prevention sheet. Erosion prevention method.