JP4167484B2 - Water shielding mat filled with bentonite - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water shielding mat filled with bentonite.
[0002]
[Prior art]
In order to form a water-impervious layer in waste disposal sites, reservoirs, regulating ponds, and scenic ponds, it has been proposed to construct a water-impervious structure using bentonite mixed soil. In this method, bentonite mixed soil is spread on a water-impervious construction surface, and compacted by rolling and compacting to form a water-impervious layer with a small water permeability coefficient.
[0003]
By the way, in actual construction, there is a variation in the water-imperviousness due to the spread thickness of bentonite mixed soil, the rolling method, etc., especially on inclined surfaces, there are concerns such as poor construction stability and quality reliability. there were.
[0004]
On the other hand, a method has been developed in which a bag body made of a water-permeable fabric is laid on a water-impervious construction surface, and bentonite powder particles are filled therein to form a water-impervious mat (see Patent Document 1).
[0005]
In this construction method, the swelling thickness of bentonite in a state where water has permeated is restricted and regulated by the interval adjusting means provided between the fabrics constituting the outer skin of the water-impervious mat, and the construction thickness is uniform and shielded. There is an advantage that water is uniform.
[0006]
[Patent Document 1]
Japanese Patent No. 2735706 Specification
[Problems to be solved by the invention]
Synthetic fiber twisted yarn, tape, synthetic resin sheet or the like is used as the spacing adjusting material used in this water-proof mat, but synthetic fiber twisted yarn is usually used. Further, the waterproof mat is sewed in a factory by passing an interval adjusting material made of synthetic fiber twisted yarn through the top and bottom of the mat.
[0008]
Then, by filling the mat with bentonite by pumping at the construction site, the mat is expanded, and the expansion thickness is regulated by the interval adjusting material.
[0009]
However, for example, the permeability coefficient k required for a soil impervious layer considering application to a waste disposal site is k = 1.0 × 10 ⁻⁶ cm / s or less, which is the soil impervious standard. However, the water permeability coefficient k of the arrangement part of the interval adjusting material is on the order of 10 ⁻⁵ to 10 ⁻⁴ cm / s, which is considerably lower than the required value, causing a problem in application.
[0010]
FIG. 3 is a graph showing the relationship between the number of arrangements per area of 19.6 cm ² and the water permeability when synthetic fiber twisted yarn is used as the spacing adjusting material. As is apparent from this graph, the permeability coefficient tends to increase as the number of twisted yarns arranged increases, and it has been confirmed that there is a problem in water shielding at the twisted yarn placement site.
[0011]
Thereby, it is presumed that the space between the fibers of the twisted yarn passing through the upper and lower sides of the water-impervious mat forms a water supply due to capillary action and performs a water-conducting action on the inside of the mat.
[0012]
That is, as shown in FIG. 4, the twisted yarn a is a strand a1 formed by bundling several dozens of strands (child strands) a1 and gathering them further to form a single strand a1. It is presumed that a space portion b is formed in the center position of the aggregate of the strands a1 and water is permeated into the inside through the space portion b. In addition, what is shown with the code | symbol c in a figure is the bentonite powder with which the periphery of the strand a was filled.
[0013]
Therefore, although it is sufficient to reduce the number of arrangement of the spacing adjusting members, in this case, the thickness of the mat becomes irregular, and the expansion cannot be restricted, so that the water shielding property is also reduced at the maximum expansion position.
[0014]
The present invention solves the above-mentioned problems, and its purpose is to prevent the water-imperviousness decrease caused by the spacing adjusting material by configuring the spacing adjusting material with a material having a non-water-conducting action. A water shielding mat filled with bentonite is provided.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the water-proof mat of the present invention is constructed by laying a bag body made of a water-permeable fabric whose periphery is closed and whose expansion thickness is limited by a space adjusting material on the water-blocking construction surface. Bentonite is filled inside to make a water-impervious mat, and when the water penetrates into the water-impervious mat, it is used in a construction method for forming a water-impervious layer by hydrating and swelling the bentonite.
The gap adjusting member, along with the resin coating results in water repellency to the twisting, and characterized by being composed of a water-impermeable bundling material formed by filling a resin into the space between the strands of which the twisted yarns To do.
[0016]
Therefore, in the present invention, water is not formed by the space between the strands constituting the twisted yarn , thereby preventing water from penetrating into the water-impervious mat, and having a water-blocking performance suitable for the water-blocking property of bentonite. Obtainable.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a waste disposal site 1 to which the present invention is applied. This disposal site 1 is constructed using slopes such as mountain valleys, and is covered with a water-impervious work 10 from the slope 1a to the bottom 1b, and the peripheral ground E and the disposal site 1 are liquid-tight. It is divided into.
[0019]
A water-impervious mat 12 is laid on one surface over the slope portion 1a and the bottom surface portion 1b of the water-impervious work 10. The upper edge of the water-impervious mat 12 is wound around and fixed to a fixing work 14 embedded in the ground surface portion GL in the vicinity of the slope portion 1a, and is covered with a protective soil 16 on the bottom surface portion 1b side.
[0020]
Further, a water-impervious sheet 18 and a protective mat 20 are laid on the upper surface of the slope portion 1 a of the water-impervious mat 12, and the lower edge is positioned on the bottom surface portion 1 b and is also fixed with the protective soil 16.
[0021]
In the above layer structure, the water-impervious sheet 18 is a sheet made of, for example, rubber-asphalt, the protective soil 16 is made of general earth and sand such as mountain sand and locally collected earth, and the protective mat 20 is made of a material such as nonwoven fabric. Among them, the upper edge of the water-impervious sheet 18 is wound around the fixing work 14 and fixed together with the water-impervious mat 12.
[0022]
After the construction of the above-described water-impervious work 10, waste and cover soil are alternately buried in the disposal site 1 and can be used until the inside of the disposal site 1 is completely buried.
[0023]
The water-impervious mat 12 has a pair of water-permeable fabrics 24a made of polyester resin fiber woven fabric with closed eyes and the like closed by sewing or the like as shown in an enlarged view in part of FIG. The gap adjusting member 24b connects the two fabrics 24a at a predetermined interval, and the bentonite 26 filled in the bag-like interior between the two fabrics 24a.
[0024]
The maximum thickness of the water-impervious mat 12 is regulated to, for example, 5 to 10 cm according to the length of the interval adjusting member 24b. Moreover, although the width | variety per sheet is 2-4 m, for example, it can join with a field stitch | suture or a surface fastener etc. with respect to a length direction, and can cover a required area part.
[0025]
The bentonite 26 may be a powder or granular bentonite alone, and a soil material made of recycled materials such as mountain sand, locally generated soil, pearlite, molten slag and the like in an appropriate mixing ratio within a range that does not impair the water shielding property. Materials may be mixed.
[0026]
The bentonite 26 functions as a water-impervious material as described above, and the property of this bentonite is that it absorbs water 5 to 10 times or more of its own weight and swells. The surface layer swells with water to form an initial water shielding layer.
[0027]
And although the water-impervious mat 12 tries to expand in the thickness direction due to the swelling of the bentonite 26, the thickness is regulated to 5 to 10 cm by the distance adjusting member 24b, so the inside is kept dry. Then, it is accumulated in the water-impervious mat 12 as a swelling surplus force, and thereafter functions as a water-impervious material.
[0028]
For example, the spacing adjusting member 24b is made of a twisted yarn coated with a resin to provide water repellency, and the space serving as the water supply is closed with a resin. As this resin, urethane, vinyl chloride, or the like is used. .
[0029]
In addition, a single linear or round bar-like or tape-like fiber without twisting is also used, and examples of this type of fiber include polyethylene and polypropylene.
[0030]
The space adjusting member 24b made of each material is attached by penetrating up and down 12 of each water-permeable fabric 24a by a normal attachment method. In addition, if a water repellent resin etc. are apply | coated also to the penetration part with respect to each water-permeable fabric 24a of the space | interval adjustment material 24b, the water shielding effect can be increased further.
[0031]
FIG. 2 shows a case where a water permeability coefficient is measured in the case of using an interval adjusting material made of each of the above materials and a conventional synthetic fiber twisted yarn. Moreover, the water permeability coefficient of the bentonite filling part is also shown. In addition, the arrangement | positioning space | interval of each raw material used for the measurement was 100 mm space | interval both vertically and horizontally, and 1100 decitex was used as the water-permeable fabric 24a, and the polyester resin fiber woven fabric which was comparatively clogged was used.
[0032]
From the results shown in FIG. 2, the material using the conventional spacing adjusting material is about 1.0 × higher than the disposal site soil impermeable standard (k = 1.0 × 10 ⁻⁶ cm / s). ^10-5 cm / s, low water barrier, but when coated twisted yarn or single fiber is used, it is shown that both meet the standards, impairing water barrier performance by bentonite It was confirmed that there was nothing to do.
[0033]
【The invention's effect】
As is clear from the above description, in the water-impervious mat filled with bentonite according to the present invention, it is possible to prevent a decrease in water-imperviousness caused by the spacing adjusting material.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view including a part of an enlarged portion in which the method of the present invention is applied to a waste disposal site.
FIG. 2 is a graph showing a relationship between a water permeability coefficient and an interval adjusting material.
FIG. 3 is a graph showing a relationship between a water permeability coefficient and an arrangement interval of a conventional interval adjusting material.
FIG. 4 is a schematic enlarged view showing a defect of a conventional interval adjusting material.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Waste disposal site 10 Impermeable work 12 Impervious mat 24a Permeable cloth 24b Spacing adjustment material 26 Bentonite

Claims (1)

A bag body made of a permeable fabric whose periphery is closed and whose expansion thickness is limited by a gap adjusting material is laid on a water-impervious construction surface, and the bag body is filled with bentonite to form a water-impervious mat. When the water penetrates into the mat, the bentonite is hydrated and swollen and used in a construction method for forming a water shielding layer.
The gap adjusting member, along with the resin coating results in water repellency to the twisting, and characterized by being composed of a water-impermeable bundling material formed by filling a resin into the space between the strands of which the twisted yarns Water shielding mat filled with bentonite.

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