JP2004195376A - Water barrier mat filled with bentonite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water barrier mat filled with bentonite constituted so as to prevent the lowering of water barrier properties caused by an interval adjusting material. <P>SOLUTION: A bag body, which comprises a pair of water permeable fabrics 24a of which the peripheries are closed and between which an interval is formed so as to be restricted by the interval adjusting materials 24b, is laid on a water barrier execution surface and filled with bentonite to form a water barrier mat 12. This water barrier mat 12 is laid on the water barrier execution surface and water penetrates in the water barrier mat 12 to hydrate and swell bentonite 26 to form a water impermeable layer on the inside surface layer of the water barrier mat 12. In this constitution, each of the interval adjusting materials 24b is constituted of a water impermeable bundled material having no gaps between fibers. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a waterproof mat filled with bentonite.
[0002]
[Prior art]
It has been proposed to construct a water-blocking structure using bentonite-mixed soil when forming a water-blocking layer at a waste disposal site, a reservoir, a regulating pond, or a scenic pond. In this method, a bentonite-mixed soil is spread on a water-impervious construction surface and compacted by compaction to form a water-permeable layer having a small water permeability.
[0003]
By the way, in actual construction, the water barrier varies due to the thickness of the bentonite mixture soil and the method of compaction, and there are concerns about poor construction stability and poor quality reliability, especially on slopes. there were.
[0004]
On the other hand, a method has been developed in which a bag made of a water-permeable fabric is laid on a water-impervious construction surface, and the inside thereof is filled with bentonite powder to form a water-impervious mat (see Patent Document 1).
[0005]
In this method, the swelling thickness of bentonite in a state where water has penetrated is restricted and regulated by a spacing adjusting means provided between the fabrics constituting the outer skin of the water-blocking mat. There are advantages such as uniformity of aqueous solution.
[0006]
[Patent Document 1]
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 for the water-proof mat, but usually, synthetic fiber twisted yarn is used. In addition, the water-blocking mat is sewn in a factory by passing a gap adjusting material made of a synthetic fiber twisting thread through the top and bottom of the mat.
[0008]
Then, at the construction site, the mat is filled with bentonite by pumping and pumping, so that the mat is inflated, and the thickness of the inflated material is regulated by the spacing adjusting material.
[0009]
However, for example, a permeability coefficient k required for a soil impermeable layer in consideration of application to a waste disposal site is k = 1.0 × 10 ⁻⁶ cm / s or less, which is set as a soil impermeable standard. However, the permeability coefficient k of the arrangement portion of the spacing adjusting material was in the order of 10 ⁻⁵ to 10 ⁻⁴ cm / s, which was considerably lower than the required value, and there was 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 a synthetic fiber twisted yarn is used as the spacing adjusting material. As is clear from this graph, as the number of twisted yarns increases, the water permeability tends to increase, and it has been confirmed that there is a problem in the water shielding at the location where the twisted yarns are arranged.
[0011]
Thus, it is presumed that the space between the fibers of the twisted yarn penetrating the upper and lower sides of the water-insulating mat forms a water supply (Mizumichi) by capillary action and performs a water-conducting action inside the mat.
[0012]
That is, as shown in FIG. 4, the twisted yarn a is a strand (stub wire) a1 obtained by bundling dozens of many yarns and gathering them, and further gathering three to four strands to form a single strand. It is presumed that a space b is formed at the center of the aggregate of the strands a1 and a space b is formed at the center of the aggregate of the strands a1, and water penetrates through the space b. In addition, what is shown by the code | symbol c in the figure is the bentonite powder filled at the periphery of the yarn a.
[0013]
Therefore, although it is sufficient to reduce the number of the spacing adjusting members, in this case, the thickness of the mat is irregular, and the expansion cannot be restricted. Therefore, the water blocking at the maximum expansion position is also reduced.
[0014]
The present invention has been made to solve the above problems, and its object is to configure a gap adjusting material with a material having a non-water-conducting effect so that a decrease in water blocking caused by the gap adjusting material can be prevented. The present invention provides a water-proof mat filled with bentonite.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the waterproofing mat of the present invention is configured such that a bag made of a water-permeable cloth whose periphery is closed and whose expansion thickness is restricted by a spacing adjusting material is laid on a waterproofing work surface, Filling the inside with bentonite to form a water-blocking mat, water penetrates into the water-blocking mat, and is used in a construction method in which the bentonite hydrates and swells to form a water-blocking layer, and the gap adjusting material is It is characterized by being made of an impermeable binding material having no space between fibers.
[0016]
Therefore, in the present invention, a water supply (water path) is not formed by the fiber space, whereby it is possible to prevent water from penetrating into the water impermeable mat, and it is possible to obtain a water impermeable performance adapted to the water impermeability of bentonite.
[0017]
In the present invention, as the water-impermeable binding material, a twisted yarn made water-repellent by resin coating, or a linear or rod-like fiber or a tape-like fiber without twisting can be used.
[0018]
BEST MODE FOR CARRYING OUT 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. The disposal site 1 is constructed using a slope such as a mountain valley, and is covered with a water-blocking work 10 from the slope 1a to the bottom 1b, and the peripheral ground E and the disposal site 1 are liquid-tight. Is divided into
[0019]
A water-blocking mat 12 is laid all over the slope 1a and the bottom 1b of the water-blocking construction 10. The upper edge of the water-impervious mat 12 is wound around and fixed to a fixing work 14 buried in the ground surface portion GL in the vicinity of the slope portion 1a, and is covered with protective soil 16 on the bottom surface portion 1b side.
[0020]
Further, a water-blocking sheet 18 and a protection mat 20 are laid on the upper surface of the slope 1a of the water-blocking mat 12, and the lower edge is located on the bottom 1b, and the same is fixed with the protection soil 16.
[0021]
In the above-described layer structure, the impermeable 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 sand, and the protective mat 20 is made of, for example, a material such as nonwoven fabric. The upper edge of the water-impervious sheet 18, together with the water-impervious mat 12, is wound around and fixed to a fixing work 14.
[0022]
After the construction of the water shield 10, the waste and the cover soil are alternately buried in the disposal site 1, and the waste can be used until the inside of the disposal site 1 is reclaimed.
[0023]
As shown in an enlarged view in a part of FIG. 1, the waterproof mat 12 includes a pair of permeable fabrics 24a made of a woven polyester resin fiber woven cloth and the like, which is closed in a bag shape by sewing or the like. The space adjusting member 24b connects the two fabrics 24a at a predetermined interval, and the bentonite 26 is filled in the inside of the bag between the two fabrics 24a.
[0024]
The maximum thickness of the waterproof mat 12 is regulated to, for example, 5 to 10 cm in accordance with the length of the gap adjusting member 24b. In addition, the width per sheet is, for example, 2 to 4 m, but in the length direction, it can be joined by local suturing or a hook-and-loop fastener to cover a necessary area.
[0025]
As the bentonite 26, powder or granular bentonite alone may be used, or a soil composed of recycled material such as mountain sand, locally generated earth and sand, or pearlite or molten slag at 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-blocking material as described above, and has a property of absorbing water 5 to 10 times or more of its own weight and swelling, but has penetrated into the surface of the water-blocking mat 12. The water swells the surface layer to form an initial impermeable layer.
[0027]
The water impermeable mat 12 tends to expand in the thickness direction due to the swelling of the bentonite 26, but the thickness is regulated to 5 to 10 cm by the spacing adjusting material 24b, so that the inside is kept dry. Then, the water is accumulated in the impermeable mat 12 as surplus swelling power, and thereafter, the function of the impermeable material is maintained.
[0028]
The spacing adjuster 24b is, for example, a resin that coats the twisted yarn with a resin to provide water repellency and has a space that serves as the tap water closed with a resin. As the resin, urethane, vinyl chloride, or the like is used. .
[0029]
In addition, a single linear or round rod-shaped or tape-shaped fiber without twisting may be used, and examples of this kind of fiber include polyethylene and polypropylene.
[0030]
The spacing adjusting member 24b made of each of these materials is attached through the upper and lower portions of each of the water permeable fabrics 24a by a normal attaching method. In addition, if a water-repellent resin or the like is applied to the penetrating portion of each of the spacing adjusting members 24b with respect to each of the water-permeable cloths 24a, the water-shielding effect can be further increased.
[0031]
FIG. 2 shows a case where the water permeability was measured in the case where the spacing adjusting material made of each of the above materials and a conventional synthetic fiber twisted yarn were used. In addition, the permeability coefficient of the bentonite-filled portion is also shown. The arrangement intervals of the materials used in the measurement were 100 mm in both the vertical and horizontal directions, and the water-permeable cloth 24a was 1100 dtex and a relatively tightly woven polyester resin fiber cloth.
[0032]
From the results shown in FIG. 2, the results obtained by using the conventional spacing adjusting material were about 1.0 ×, which is higher than the soil impermeability standard of the disposal site (k = 1.0 × 10 ⁻⁶ cm / s). It is 10 ⁻⁵ cm / s, and the water barrier property is low. However, when a coated twisted yarn or a single fiber is used, it is shown that both meet the criteria, and the water barrier performance by bentonite is impaired. It was confirmed that there would be no.
[0033]
【The invention's effect】
As is clear from the above description, in the water-blocking mat filled with bentonite according to the present invention, it is possible to prevent a decrease in water-blocking due to the spacing adjusting material.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view including an enlarged part of a part 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 and an interval adjusting material.
FIG. 3 is a graph showing a relationship between a water permeability and an arrangement interval of a conventional interval adjusting member.
FIG. 4 is a schematic enlarged view showing a defect of a conventional gap adjusting material.
[Explanation of symbols]
1 Waste Disposal Site 10 Waterproofing Work 12 Waterproofing Mat 24a Water-permeable Fabric 24b Interval Adjustment Material 26 Bentonite

Claims (3)

A bag made of a water-permeable cloth whose periphery is closed and whose expansion thickness is restricted by a spacing adjusting material is laid on the water-impervious construction surface, and the inside of the bag is filled with bentonite to form a water-impervious mat. By penetrating water into the mat, the bentonite is hydrated and swelled, and is used in a construction method of forming a water barrier layer,
The water-blocking mat filled with bentonite, wherein the spacing adjusting material is made of a non-permeable tying material having no space between fibers. The water impermeable mat filled with bentonite according to claim 1, wherein the impermeable tying material is a twisted yarn made water repellent by resin coating. The water impermeable mat filled with bentonite according to claim 1, wherein the impermeable binding material is a linear or rod-like fiber or a tape-like fiber that is not twisted.

Images