JPH07137207A - Water-barrier sheet for civil engineering work - Google Patents

Abstract

PURPOSE:To provide a water barrier sheet for civil engineering work, which makes a highly water-absorbent resin swell with water leaked from the hole when a waterproof layer of a toxic wastes final disposing site or water reser voir, etc., is damaged, and thus prevents a water leakage from generating, and does not require maintenance. CONSTITUTION:The water barrier sheet is a sheet formed object which is laid under a waterproof layer for civil engineering work, and a highly water- absorbent macro-molecular substance is diffused on a sheet formed base material by a ratio of 10-3000g/m<2>, and the highly water-absorbent macro-molecular substance is covered by a cover sheet, or is carried on the sheet formed base material by bonding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof sheet for civil engineering, and more particularly, to prevent water leaking from a waterproof layer such as a hazardous waste final disposal site or a reservoir from leaking into the ground. It relates to a waterproof sheet for civil engineering.

[0002]

2. Description of the Related Art It is known that a hole is dug in the ground and the waste is stored in the ground as a storage means for the final disposal of the waste containing a substance harmful to the human body and the environment. Has been. If the liquid contained in the waste or rainwater that has fallen into the hole leaks from these waste storage holes, there is a problem that it may cause environmental damage such as soil pollution or groundwater pollution. In addition, there is a problem that water storage efficiency will decrease if water leaks from reservoirs for irrigation. Therefore, the following various methods have been conventionally performed as methods for preventing water leakage from these holes and ponds. (1) A method of laying a waterproof sheet made of rubber or resin on the bottom or slope of a pond. (2) A method in which a non-woven fabric is laid as a cushioning material with a predetermined thickness, for example, a thickness of 1 to 5 cm as a base material of the waterproof sheet so that the sheet is not damaged by a hard protrusion. And so on. All of these methods have a problem of poor reliability because it is almost impossible to detect water leakage at an early stage. Therefore, (3) a method of laminating the waterproof sheet and the cushion material. However, the method (3) has a problem that the cost is high and maintenance is troublesome. Therefore, the following proposals have been made as means for early detection of the water leakage. That is, (4) a pressurized fluid and a pressure sensor are enclosed in a bag formed of a waterproof sheet, and the sensor detects a pressure drop in the bag when the bag is broken and water leakage starts, so that water leakage can be detected early. The method described in Kaihei 1-225024. (6) The method described in Japanese Patent Application Laid-Open No. 1-63834, which converts leaked water into heat and detects the heat with a temperature sensor to detect the leaked water at an early stage. (6) The method described in JP-A-4-134237, in which electrodes are attached to both sides of the waterproof sheet and a voltage is constantly applied, and a current flowing between the electrodes is detected to detect water leakage. (7) A method of arranging ramen-shaped fibers between two waterproof sheets, providing electrodes on each sheet, detecting a water leakage point of the sheet by flowing current, and injecting resin from the outside into the portion to stop water . The water leak detection methods shown in (4) to (7) have cost problems such as high equipment cost and troublesome maintenance, and further improvement is recognized.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and when the hazardous waste final disposal site or the waterproof layer of a reservoir is damaged, water leaking from the damaged part is lost. The purpose of the present invention is to provide a water impervious sheet for civil engineering that swells the super absorbent resin and prevents leaked water from seeping into the ground, and does not require maintenance.

[0004]

[Means for Solving the Problems] A construction of a water-impermeable sheet for civil engineering according to the present invention for achieving the above object is a sheet-like article laid under a waterproof layer for civil engineering, which is a super absorbent polymer. The substance is dispersed and arranged on the sheet-shaped substrate at a rate of 10 to 3000 g / m ² , and is carried on the sheet-shaped substrate by covering with a cover sheet or adhering.

The waterproof layer is not particularly limited, but generally a conventionally used natural or synthetic rubber sheet or a flexible synthetic resin, for example, a vinyl chloride-based or unsaturated polyester-based waterproof sheet is used. be able to. The super absorbent polymer is not particularly limited as long as it is super absorbent and does not adversely affect the environment, for example, a natural system such as cellulose / acrylonitrile polymer, starch / acrylonitrile polymer, etc. , Acrylic acid / vinyl alcohol copolymer, sodium acrylate polymer, sodium acrylate / acrylamide copolymer, polyethylene oxide modified product, isobutylene / maleic anhydride copolymer, etc. A synthetic type is preferable because it is difficult to decompose in soil, particularly in moist soil.

The sheet-shaped base material is a flexible sheet, and is not particularly limited as long as it has strength required for transportation, laying, etc. and is resistant to alteration in soil. Preferred sheet-like base materials are cloth-like materials obtained by woven and knitting fibers, non-woven fabrics, sheet-like sponge-like materials, and the like, and porous materials having a high water-absorbing property can be stably introduced into pores. It is preferable because it can be carried. Further, the non-woven fabric is preferably made of a long fiber material in terms of strength and the like. The fibers that can be used are not particularly limited, but preferred fibers include polyethylene terephthalate fibers, polypropylene fibers, cotton, and palm fibers.

The cover sheet may be made of the same material as the sheet-shaped substrate, or may be made of other synthetic resin film or sheet. As a means for supporting the superabsorbent polymer substance on the sheet-shaped substrate, the following means can be used. That is, i. A sheet of base material is sprayed with a certain amount of powdery super absorbent polymer, and a cover sheet is laminated on the base material, followed by thermocompression bonding, stitching with a needle punch used when manufacturing fibers and nonwovens, quilting means, etc. A method in which the elements are integrated by means such as suturing by means of, and a joining means such as a metal needle that bends the tip after inserting. In the thermocompression bonding, when the super absorbent polymer used is not a heat-fusible substance, a heat-fusible substance is added, or a sheet-like material having a heat-fusible property is laminated between them. It can be thermocompression bonded by means.

Ii. It is possible to stack a plurality of sheet-shaped base materials and blow a predetermined amount of powdery highly water-absorbent polymer substance into them to integrate them as described above. iii. Super absorbent polymer is mixed with binder resin,
A method of coating on one side or both sides of a sheet-shaped substrate. iv. A method in which a highly water-absorbing polymer substance is applied to a sheet-shaped substrate in the same manner as described above, and a cover sheet is laminated thereon. Each means such as can be used. When the super absorbent polymer is treated as a solid, it is in powder form.In this case, the powder form means a state in which it is made into fine particles, and there is no particular limitation on the particle size, and it is easy to touch water. As long as it can swell, the particle size does not have to be uniform.

The amount of super absorbent polymer used depends on
Water absorption capacity, water absorption swelling rate, sheet of super absorbent polymer
It depends on the method of supporting it on the base material.
0 g / m²It is necessary to support the sheet-shaped substrate at a ratio of
200 to 1500 g / m ²Is more preferable. High water absorption
The amount of use of high molecular weight polymer is 10g / m²In the following, the invention
The desired water-blocking effect is not exhibited, and 3000g
/ M²If it exceeds the limit, the water pressure resistance of the sheet will be higher than necessary.
It becomes uneconomical.

The method of laying the water-impermeable sheet for civil engineering can be performed in the same manner as the conventional method of laying a waterproof sheet. When laying the water-impermeable sheets, it is preferable to stack the water-impermeable sheets so that no gap is formed in the superabsorbent layer, but it is not always necessary to bond them together. The means for providing the waterproof layer on the water-proof sheet for civil engineering is not particularly limited and can be performed in the same manner as in the past. However, if there is a risk of damaging the waterproof sheet for main civil engineering when laying the waterproof layer, a protective layer may be provided between them.

[0011]

When the water barrier sheet for civil engineering of the present invention is laid under the waterproof layer, if water leakage starts due to holes or cracks in the waterproof layer for some reason, high water absorption laid under it. The polymer substance swells and gels to form a water impermeable layer, thereby exerting a strong water-blocking effect and eliminating the need for maintenance.

Further, the means for supporting the highly water-absorbent polymer substance on the sheet-shaped substrate acts so as to form a uniform impermeable layer of the highly water-absorbent polymer substance. Also, when a porous material such as nonwoven fabric is used for the sheet-shaped substrate,
Cushioning property is obtained, and an action of protecting a waterproof layer such as a waterproof sheet is obtained. The water-proof sheet for civil engineering of the present invention has a water pressure resistance of 1.0 kg / cm ² or more, and even if the waterproof layer at the bottom of a waste final treatment plant or a reservoir at a depth of 10 m or more is damaged, The ability to perform can be demonstrated.

[0013]

EFFECTS OF THE INVENTION In the above-described waterproofing sheet for civil engineering of the present invention, the sheet-like base material is made to carry the superabsorbent polymer substance and is laid under the waterproof layer, so that the waterproof layer is damaged. ,
Even when water leakage occurs, the highly water-absorbent polymer substance swells with water or the like and gels to form a water impermeable layer, exhibiting strong water impermeability, and preventing water leakage. Moreover, since the maintenance of the water blocking sheet is unnecessary, it can be effectively and effectively used as a means for preventing water leakage from a waterproof layer such as a hazardous waste final disposal site or a reservoir, which is difficult to maintain. Further, when a cushioning material such as a non-woven fabric is used for the sheet-shaped base material, an effect of protecting the waterproof layer thereon, particularly the waterproof sheet, from damage can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Nakao 2-2-1 Nihombashi Muromachi, Chuo-ku, Tokyo Toray Industries, Inc. Tokyo Plant (72) Inventor Shuichi Matsumoto 18 of 1993, Ofuna, Kamakura, Kanagawa Prefecture (72 ) Inventor Mamoru Shintoku 3-2-7 Hoshikawa, Hodogaya-ku, Yokohama-shi, Kanagawa

Claims (4)

[Claims] 1. A sheet-like material laid under a waterproofing layer for civil engineering, comprising 10 to 3000 g / highly water-absorbing polymeric substance.
A water impervious sheet for civil engineering, which is dispersedly arranged on a sheet-shaped substrate at a ratio of m ² , and is carried on the sheet-shaped substrate by being covered with a cover sheet or adhered thereto. 2. The water impervious sheet for civil engineering according to claim 1, wherein the sheet-shaped substrate is made of a fiber material. 3. The water impervious sheet for civil engineering according to claim 1, wherein the sheet-shaped substrate is made of a non-woven fabric. 4. The water impervious sheet for civil engineering according to claim 3, wherein the non-woven fabric is a long fiber non-woven fabric.