JP2011196143A - Reinforcing structure of dam body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent corrosion of a dam body and permeation of rainwater into the dam body.SOLUTION: An anticorrosion and hardly-permeable mat 20 including a loofa-like mat having a water-permeable porous structure and a hardly-permeable sheet arranged on a surface of the loofa-like mat is used to cover the entire surface of at least a water-area-side slope 11 and a land-area-side slope 13 of the dam body 10 for protection. The hardly-permeable sheet of the anticorrosion and hardly-permeable mat 20 laid on the water-area-side slope 11 is removed. The entire area of the anticorrosion and hardly-permeable mat 20 laid on the water-area-side slope 11 is filled with a gravel material 30, and the entire area of the anticorrosion and hardly-permeable mat 20 laid on the slope 13 other than the water-area-side slope is filled with earth and sand 31, and plants are planted.

Description

  The present invention relates to a reinforcing structure for a dam body that partitions a water area such as a river, a pond, a lake, and the sea and a land area such as a field or a residential area, and more particularly to a reinforcing structure for a dam body that repairs an existing dam body. Is.

The dam body of the basin is built in a trapezoidal cross section with embankment of earth and sand, gravel, etc., but there are tens of thousands of ponds in the country that need to be renovated and repaired. There are concerns that it will cause enormous human and economic damage to the surrounding area.
Causes of levee body breakage mainly include erosion and scouring of slopes due to water level changes and waves and flowing water accompanying drought, and suppression of the rise of infiltration lines in the levee body due to seepage water such as rainwater. It can't be done.
Leaving the erosion and scouring of the waterside slope will cause a cross-sectional defect of the levee body and make the dam body unstable. In addition, when the infiltrating line in the levee rises, piping occurs in the levee, and the slope of the slope on the land side is collapsed.
Furthermore, if the landside slope is exposed to heavy rain or overflow, it will cause gully and erosion destruction.

As a method of rehabilitating an existing dam body, a front blade method has been known for a long time, in which the slope on the water side is excavated and removed, and a new dam is renewed by replacing the blade metal.
Further, as another method for refurbishing an existing levee body, it is known from Patent Documents 1 and 2 that the slope of the levee body is covered with a water-permeable erosion prevention mat and the erosion prevention mat is filled with earth and sand.

Japanese Patent No. 3396199 JP 2003-278129 A

The conventional levee body refurbishment techniques have the following problems.
In the <1> front blade method, the amount of excavation of the slope and the amount of blade metal for replacement are large, so that not only the repair cost increases but also the construction period takes longer.
<2> Further, the front edge metal work method requires a large construction machine such as a backhoe for renovation work.
If the levee body is in a mountainous area, it will be difficult to introduce construction machinery and it will be necessary to review the repair method.
<3> Although the rehabilitation method using the erosion prevention mat can be expected to have a certain amount of runoff prevention effect against running water, the change in water level and waves caused by the depleted water is small because the particle size of the earth and sand in the erosion prevention mat is small. Or, it was unable to exert the effect of preventing sediment loss against heavy rain.
For this reason, there has been a problem that the repair effect cannot be guaranteed over a long period of time.
<4> The refurbishment technology described in Patent Document 1 requires a sufficient filling thickness of earth and sand, so that the mat for erosion prevention becomes thicker and heavier, and there is room for improvement in mat handling and handling. There is.
Furthermore, in order to reduce the gap inside the mat and improve the trapping property of the earth and sand, the mat for preventing erosion is made by closely gathering thermoplastic resin yarns.
When the thermoplastic resin threads are densely packed, the mat becomes rigid and the followability to undulations is deteriorated. Therefore, an additional work for finishing the laying surface of the levee body to a flat surface before laying the erosion prevention mat is required.
<5> The repair technique described in Patent Document 2 is that an erosion prevention panel in which filling soil, plants, and covering soil are integrated in a panel-like porous structure is manufactured in advance, and a number of these erosion prevention panels are inclined. It is something that is lined up.
The erosion prevention panel of Patent Document 2 has the same problems as described above in Patent Document 1, and the weight per erosion prevention panel is heavy, so it only requires labor to transport and lay the erosion prevention panel. In addition, the adjacent panels must be connected using a connecting tool, which requires a lot of work.
<6> The conventional levee body refurbishment technology is intended exclusively for waterside slopes.
For this reason, a large amount of water penetrates through the top of the levee and the slope on the land side due to heavy rain, and the infiltrating line in the levee body rises, causing piping in the levee body and causing the slip on the land side slope. Or
In addition, the land side slope is exposed to heavy rains and overflows, which causes problems such as gully and erosion destruction.
<7> As described above, conventional levee body repair techniques have problems in terms of construction period, construction cost, and repair performance.
Due to recent record heavy rains and earthquakes, it is an urgent task to repair an old embankment, but no suitable repair technology has been proposed yet, and the development of countermeasure technology is eagerly desired. .

The present invention has been made in view of the above points, and an object of the present invention is to provide at least one of the following reinforcing structures for a bank body.
<1> The rise of the infiltrating line in the levee body can be suppressed while enhancing the effect of preventing erosion and scouring on the waterside slope.
<2> The effect of repairing the levee body over a long period can be guaranteed.
<3> Shorten the construction period and reduce repair costs.
<4> A large construction machine is not required and can be easily repaired even in mountainous areas.

The present invention is a levee body having a waterside slope, a top end portion, and a landside slope, a porous structure having water permeability and a non-permeable sheet attached to one side of the sponge mat, A range in which at least the water-side slope and the land-side slope of the levee body are covered and protected by the corrosion-resistant immersion mat and are laid on the water-side slope of the corrosion-resistant immersion mat. The anti-water-permeable sheet is removed, and the entire area of the anti-corrosion resistant mat laid on the slope of the water area is filled with debris, and the entire area of the anti-corrosion resistant mat laid on the slope other than the slope of the water area is filled with earth and sand. A dam body reinforcement structure characterized by being vegetated is provided.
The gravel material is preferably gravel having a particle size of 10 mm or less.
The earth and sand are preferably locally generated soil.

The present invention can obtain at least one of the following effects.
Since the present invention has the above configuration, the following effects can be obtained.
<1> The waterside slope of the levee body was covered with a corrosion-resistant immersion mat and filled with rubble material for protection.
Since gravel is larger and heavier than earth and sand, it can prevent erosion and scouring of waterside slopes while preventing runoff of rubble even under water flow, water level changes, and repeated waves.
<2> The slopes other than the waterside slopes of the levee body were covered with a corrosion-resistant infiltration mat with a non-permeable sheet and filled with earth and sand for protection.
The impervious line in the levee body is reliably prevented because the impervious sheet covering the slopes other than the water body side of the levee body and the earth and sand filled in the anti-corrosion infiltration mat work together to suppress the infiltration of rainwater. In addition to what can be done, the levee body is less likely to be eroded by heavy rain and overflow.
<3> Using rubble as a means to prevent erosion of the slope on the water body side of the levee body where a large water current acts, and using earth and sand as a means to prevent erosion of the part other than the slope on the water area, Appropriate protective measures can be taken. .
Since these gravel materials and earth and sand filled in the anti-corrosion resistant mat can be prevented for a long time, the effect of repairing the levee body can be ensured for a long time.
<4> Without using a large construction machine, after laying a lightweight anticorrosion mat on the entire slope of the levee body, the levee body can be repaired by simply filling it with debris and earth and sand.
Therefore, the construction period is short and the repair cost can be reduced.
In particular, even in mountainous areas where it has been difficult to introduce large construction machines that have been difficult to construct, it is possible to easily repair old dyke bodies.

The perspective view of the embankment which shows the reinforcement structure of the embankment which concerns on this invention Cross section of the embankment Perspective view of a corrosion-resistant immersion mat with some parts omitted Partial sectional view of the waterside slope Partial sectional view of land side slope

  Preferred embodiments according to the present invention will be described below with reference to the drawings.

<1> Levee FIG. 1 shows an example of a modified levee 10 according to the present invention.
The dam body 10 assumed by the present invention is an existing dam body such as a lake, a river, an artificial waterway, a canal, etc., which is constructed by accumulating earth and sand so that the cross-sectional shape has a trapezoidal shape. And a land-side slope 13.
Although it is desirable to apply the present invention to the repair of the existing dam body 10, it is of course possible to apply it to a new dam body.

The present invention not only repairs at least the water-side slope 11 of the dam body 10 using the anti-corrosion-resistant immersion mat 20 but also repairs the top end 12 and the land-side slope 13 together.
In addition, when the top end 12 is covered with a paving material, the laying of the anticorrosion / immersion mat 20 is omitted.

<2> Anti-corrosion-resistant immersion mat The anti-corrosion-resistant immersion mat 20 is a mat-like material for the purpose of protecting the dam body 10 having both an anti-erosion effect and a water permeation suppression effect, and has a void inside.
As shown in FIG. 3, the anticorrosion / immersion mat 20 includes a porous structure 21 having water permeability and a hardly water-permeable sheet 22 attached to one surface of the sponge matrix 21.
The strip-shaped anticorrosion-resistant mat 20 is wound up in a roll shape or conveyed in a sheet form.

<2.1> Loofah-like mat The loofah-like mat 21 is a protective member for the dam body 10, and is formed by matting a large number of thermoplastic resins having a diameter of several microns to several millimeters irregularly. It functions not only to keep sand and pebbles mixed in the sand but also earth and sand without being washed away.
Therefore, the size of the space inside the loofah mat 21 is formed to a size capable of holding the gravel material and earth and sand.

Conventional mats for preventing erosion require a mat thickness of at least about 3 cm in order to increase the filling thickness of earth and sand and increase the weight of the mat.
On the other hand, the anticorrosion mat 20 has a bottomed structure in which one side of the loof mat 21 is attached with a non-permeable sheet 22 so that the entire weight of the filled earth and sand acts on the anticorrosion mat 20. Is possible.
Accordingly, the thickness of the loofah mat 21 can be reduced to about 1.5 cm to 2.0 cm, which is thinner than the conventional one, which is convenient for transportation and handling of the anticorrosion / immersion mat 20.

<2.1.1> Raw material for loofah mats Thermoplastic resins include, for example, olefin resins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer, polyvinyl chloride, and copolymers mainly composed of vinyl chloride. Vinyl chloride resins, polyvinylidene chloride, vinylidene chloride resins such as copolymers based on vinylidene chloride, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide 6, polyamide 6/6, polyamide MXD, etc. Polyamide resins, polycarbonate, acrylic resins such as polymethyl methacrylate, styrene / butadiene thermoplastic elastomers, ethylene / propylene thermoplastic elastomers, polyester thermoplastic elastomers, polyamide thermoplastic elastomers Includes tomers.
As for the thermoplastic resin, two or more kinds of thermoplastic resins are mixed according to the strength applied to the loof mat 21, and a known additive is appropriately mixed as necessary.

  It is desirable to use waste such as pet bolts as the material for the loofah mat 21. By reusing this kind of waste, a large amount of waste can be used effectively.

<2.1.2> Method for producing loofah-like mat To produce loofah-like mat 21, for example, a thermoplastic resin heated and melted is continuously discharged from a extruder as a thread-like material, and a molding roller (not shown) A plurality of thread-like materials are irregularly entangled with a belt conveyor or the like, formed into a predetermined thickness, and then guided into a cooling solvent to be cooled and solidified.
If a thermoplastic resin that has been heated and melted is used, the thread-like materials can be fixed to each other by self-adhesion, so that no special adhesive is required.

<2.2> Non-water-permeable sheet The non-water-permeable sheet 22 is a sheet having a property that it is difficult for water to pass through, and functions to provide the anti-corrosion / immersion mat 20 with poor water permeability.
As the hardly water-permeable sheet 22, for example, a known nonwoven fabric can be used. In particular, when an inexpensive hydrophobic nonwoven fabric used for a disposable mask or the like is used, penetration of the root system of flowers and trees can be allowed while securing water permeability of about 50% by repelling water.

  As a method of attaching the hardly water-permeable sheet 22 to the loofah mat 21, the hardly water-permeable sheet 22 is attached to one surface of the self-adhesive loof mat 21 immediately before cooling and solidification in the manufacturing process of the loofah mat 21 described above. Alternatively, the hard water-permeable sheet 22 is adhered by applying an adhesive to the cured loofah mat 21.

[Renovation method of levee body]
Next, a method for repairing the dam body 10 using the anti-corrosion immersion mat 20 will be described with reference to FIGS.

<1> Laying the entire surface of the anti-corrosion-resistant mat The conventional front-blade metal method excavates and replaces the ground of an aged embankment, but in the present invention, the earth and sand are not replaced, and the surface of the embankment 10 is difficult to resist. A protective layer mainly composed of the immersion mat 20 is formed.

The method of repairing the levee body 10 will be described in detail. First, the anticorrosion / immersion mat 20 is laid on the entire surface of the waterside slope 11, the top end 12 and the landside slope 13 constituting the dam body 10. At this time, the hardly water-permeable sheet 22 is laid toward the natural mountain side.
Since the anticorrosion-resistant mat 20 is thin and lightweight, it can be easily carried into the site and deployed and laid on site.

The anti-corrosion mat 20 is laid along the transverse direction of the dam body 10 in consideration of the size of the dam body 10, the flow rate of water, etc., or in the longitudinal direction (water flow direction) of the dam body 10. Lay along.
Whatever the laying direction is, it is sufficient that the entire surface of the levee body 10 is covered with the anticorrosion / immersion mat 20. Further, if necessary, anchor pins are provided to fix the anticorrosion / immersion mat 20.
In addition, when a paved road etc. exist in the top end 12 of the dam body 10, the anti-corrosion infiltration mat | matte 20 is laid on the whole surface of the water area side slope 11 and the land area side slope 13. FIG.

In addition, the portion corresponding to the laying range of the water-side slope 11 of the anti-corrosion proof mat 20 is removed by removing the non-permeable sheet 22 before laying, or a large number of cuts are made in the non-permeable sheet 22. Keep it.
The reason why the anticorrosion-resistant immersion mat 20 corresponding to the laying range of the water surface side slope 11 is subjected to the pretreatment is to make the water level in the dam body 10 follow the water level change on the water region side after the construction.

<2> Filling of rubble material Conventionally, the erosion prevention mat laid on the waterside slope 11 of the dam body 10 was filled with earth and sand.
On the other hand, in the present invention, the rubble material 30 is filled in the anticorrosion-resistant immersion mat 20 laid on the waterside slope 11 of the dam body 10.
The reason why the gravel material 30 is filled in place of the earth and sand is not only the flow velocity but also the effect of preventing the loss of water against the change in the elevation of the water level, waves, or rainwater.
As the gravel material 30, billet gravel of 10 mm or less is suitable.
The filling range of the gravel material 30 may be the entire surface of the water area side slope 11 or may be up to a high water level position of the water area side slope 11.

  When filling the rubble material 30, spreading the rubble material 30 on the anticorrosion resistant immersion mat 20 and then rolling it with a vibrator or the like increases the effect of preventing the rubble material 30 from flowing out.

<3> Filling earth and sand The earth and sand 31 is filled into the anti-corrosion infiltration mat 20 laid on the top end 12 and the land-side slope 13 of the dam body 10. Locally generated soil is used for the earth and sand 31.
When the bottom half of the waterside slope 11 is filled with the gravel material 30, the exposed upper half of the waterside slope 11 is also filled with earth and sand 31.
As described above, with respect to the anticorrosion-resistant immersion mat 20 laid on the entire surface of the dam body 10, the waterside slope 11 which is always in contact with water is filled with the debris 30, and the other areas are filled with earth and sand 31.

Since the anti-corrosion-resistant mat 20 has a bottomed structure in which one side of the loof mat-like mat 21 is closed with a non-permeable sheet 22, the entire weight of the filled earth and sand 31 can be imparted to the anti-corrosion-resistant mat 20. is there.
Therefore, compared with the case where the poorly water-permeable sheet 22 is not provided, it is not necessary to make the filling thickness of the earth and sand 31 excessively thick.

<4> Vegetation Vegetation is vegetated based on the earth and sand 31 filled in the top end 12 and the land-side slope 13 of the dam body 10.
As the vegetation method, vegetation is carried out by a known method such as sowing seeds or fertilizers or performing turf lawn.
As shown in an enlarged view in FIG. 5, the root system of the plant 40 continues to grow in the earth and sand 31 while being entangled with the loof mat-like mat 21, and further breaks through the hardly water-permeable sheet 22 and extends to the natural ground side of the levee body 10. As a result, not only can the bank body 10 be greened, but also the fixability of the anticorrosion / immersion mat 20 can be promoted.
The same applies to the case where seeds fly or plants around the levee body 10 advance to naturally vegetate the dam body 10.

[Characteristics of the embankment]
Next, the characteristics of the improved dam body 10 will be described.

<1> Erosion Prevention Action on Waterside Slope As shown in FIG. 4, the waterside slope 11 of the dam body 10 is covered with an anticorrosion resistant mat 20 filled with a gravel material 30.
The debris material 30 filled in the anti-corrosion resistant mat 20 has a large particle size and heavy weight compared to earth and sand, and therefore has a high anti-runoff effect.
Therefore, not only the water flow but also the water level ups and downs, waves, and the like act on the waterside slope 11, the debris 30 is reliably prevented from flowing out, and the waterside slope 11 on the back of the anticorrosion mat 20 is Erosion and scouring can be prevented.
In the unlikely event that a portion of the debris 30 flows out of the anticorrosion-resistant immersion mat 20 due to a collision of driftwood or the like, the debris 30 is refilled.

<2> Rainwater Permeation Prevention Action As shown in FIG. 2, the anticorrosion / immersion mat 20 laid on the top end 12 and the land-side slope 13 is provided with a non-permeable sheet 22 having a property that it is difficult for water to pass through.
Therefore, even if a large amount of rain falls on the levee body 10, most of the rainwater is caused to flow down by the hardly permeable sheet 22 to suppress the penetration into the dam body 10.
Thereby, it can suppress that the level of the infiltrating line 14 in the dam body 10 rises excessively by rainwater, and can prevent the piping accompanying the raise of an infiltrating line and the sliding destruction of the land-side slope 13.

<3> Erosion Prevention Action on Top and Land Side Slopes The top end 12 and the land side slope 13 of the dam body 10 are covered with an anticorrosion resistant mat 20 filled with earth and sand 31.
Therefore, even if the top 12 and the land-side slope 13 of the dam body 10 are exposed to a large amount of water due to flooding, overflow, or heavy rain, the anti-corrosion mat 20 prevents the earth and sand 31 from being washed away, and at the same time, the anti-corrosion is difficult. The outflow of earth and sand on the back surface of the immersion mat 20 is also suppressed.
Therefore, even if the submerged body 10 is flooded or overflowed, it is possible to reliably prevent the top end 12 and the land-side slope 13 from being damaged or eroded.

  As described above, the present invention not only covers the entire surface of the levee body 10 with the anticorrosion / immersion mat 20 but also uses the filler on the waterside slope 11 and the landside slope 13 for a long period of time. Thus, erosion destruction of the entire surface of the bank body 10 can be prevented.

10 ... dam body 11 ... water side slope 12 ... top end 13 ... land side slope 14 ... infiltration line 20 ... Anti-corrosion-resistant immersion mat 21 ... Loofah-like mat 22 ... Non-permeable sheet 30 ... Gravel 31 ... Earth and sand

Claims (2)

A levee body having a waterside slope, a top end portion and a landside slope,
Using a corrosion-resistant immersion mat comprising a porous structure and a water-permeable mat, and a water-permeable sheet attached to one side of the mat,
Cover the entire surface of at least the water-side slope and land-side slope of the levee body with the anti-corrosion-resistant immersion mat to protect it,
Removing the poorly permeable sheet over a range to be laid on the waterside slope of the anti-corrosion-resistant mat;
Fill the entire area of the anti-corrosion and immersion mat laid on the waterside slope with a gravel material,
It is characterized by vegetation filled with earth and sand in the entire area of the anti-corrosion infiltration mat laid on the slope other than the waterside slope,
Reinforcement structure of the embankment.   The reinforced body reinforcing structure according to claim 1, wherein the gravel material is gravel having a particle size of 10 mm or less.

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