JPH07110280A - Method for detecting defective part of water-stopping sheet - Google Patents

Abstract

PURPOSE:To easily, rapidly, and easily perform detection operation in laying field at the same time accurately specify a defective part. CONSTITUTION:The upper surface of a water-stopping sheet is covered with an airtight sheet 15 at the same time when the surrounding of the airtight sheet 15 is stuck to the upper surface of the water-stopping sheet, thus forming a closed space 16 between the water-stopping sheet and the airtight sheet 15. Further. a pressure resistant hose 17 is inserted into the closed space 16 and then air is sucked by a vacuum pump 18 to set the closed space 16 to a negative pressure state. Then, the negative pressure state is left for a while at the same time when the change in pressure is observed by a pressure gauge 20 and then the presence or absence of a defective part is detected by sensing the reduction in a negative pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a defect in a laid water shield sheet.

[0002]

2. Description of the Related Art For example, in a landfill type waste disposal site for dumping industrial waste or general waste, in order to prevent sewage leaking from the disposal site from infiltrating underground and causing environmental pollution, It is obligatory to carry out a seepage control work on the bottom of the. As such a water barrier, certainty, safety,
From the viewpoint of workability and economy, a method of laying a soft synthetic resin-based or rubber-based waterproof sheet is adopted. In addition, in order to prevent leakage of stored water, a water barrier sheet is laid on the bottom of facilities that store water in recesses such as water hazards in golf courses, simple reservoirs, reservoirs or pools. It Further, in an underground structure or the like, a water blocking sheet may be laid over the structure in order to prevent groundwater or the like from leaking into the structure.

[0003]

However, such a water-blocking sheet sometimes has a pinhole-like ventilation hole in the sheet itself at the time of manufacture. Further, the water impervious sheet may be partially damaged due to contact with the projections or the like during transportation or installation of the impermeable sheet. In addition, it is difficult to cover the bottom surface of storage facilities such as waste disposal sites and reservoirs having a vast area or the perimeter of a structure with a single waterproof sheet at a time because it is difficult to construct multiple waterproof sheets. At the laying site, the divided pieces are laid by joining and integrating the ends by welding or pressure bonding with an adhesive.
Poor joining may occur at such joints.

Then, when the waste material is discarded or the stored water is stored while leaving the defective portion of the water-blocking sheet,
There is a risk that sewage and stored water will leak out from such defective parts.

Further, since it is difficult to repair the defective portion after discarding the waste or after storing the stored water, it is desirable to detect and repair the defective portion of the waterproof sheet when laying the waterproof sheet.

[0006] Various methods have been proposed for detecting such a defect portion when laying a water-blocking sheet. In these methods, the defect portion can be detected and specified easily, quickly and surely at the installation site. There was a problem that I could not do it.

Therefore, the present invention has been made by paying attention to the above-mentioned conventional problems, and the detection work can be performed easily, quickly and easily at the laying site, and
It is an object of the present invention to provide a method for detecting a defective portion of a water-blocking sheet, which is capable of accurately detecting and specifying the defective portion.

[0008]

The present invention has been made to achieve the above object, and its gist is a method for detecting a defective portion of a water-blocking sheet for detecting a defective portion of a laid water-blocking sheet. While covering a predetermined region of the upper surface of the water-permeable sheet with an airtight sheet, the periphery of the airtight sheet is brought into close contact with the upper surface of the water-impermeable sheet, and the water-impermeable sheet and the airtight sheet By forming a closed space between them, sucking or pressurizing the closed space, and detecting a change in the pressure in the closed space after the suction or pressurization, the defective portion of the portion covered by the airtight sheet It is a method for detecting a defective portion of a water-blocking sheet, which is characterized by detecting the presence or absence of water.

Further, according to the method of detecting a defective portion of a water-impervious sheet of the present invention, when a defective portion of the water-impermeable sheet is detected, the area covered with the airtight sheet is sequentially narrowed. Continue to detect the presence of defects,
It is preferable to specify the position of the defective portion.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a waste disposal site 10 in which the impermeable sheet 11 is laid on the entire bottom surface while adopting the impermeable sheet defect detection method according to the present invention. That is, the waste disposal site 10 is formed by excavating a vast site in a mountainous area, for example, in a concave shape. A water impervious sheet 11 is laid on the bottom surface of the recess into which the waste H is put, and above it. Is laminated with a sand mat 12 as a protective mat, and thereafter waste H is placed above them.
It will be dumped and landfilled.

The water-blocking sheet 11 is made of, for example, a soft synthetic resin-based or rubber-based sheet member. In this embodiment, the single sheet is a vast waste disposal site 10.
Since it is not possible to cover the entire bottom surface area of the unit at once, at the work site, a unit waterproof sheet of a predetermined size suitable for construction, as shown in FIG. 2, for example, by welding or pressure bonding with an adhesive, The end portions are overlapped and joined to each other as a joint portion 13, which is integrally laid to a size capable of covering the bottom surface of the waste disposal site 10.

The defect detection method of this embodiment is to detect the defect of the water blocking sheet 11 laid on the bottom surface of the waste disposal site 10. That is,
The impermeable sheet 11 may have a pinhole-like ventilation hole in the sheet itself at the time of manufacturing, and may be partially damaged by coming into contact with a protrusion or the like during transportation or laying. Further, there may be a case where the joint portion 13 has a joint failure. Therefore, if the waste is dumped while leaving the defective part of the water-impervious sheet, there is a risk that sewage will leak from the defective part, and even if the defective part is found after the waste is discarded, Since the repair is not easy, the defect detection method of this embodiment is adopted in order to facilitate the repair by finding the defect at an early stage when the impermeable sheet 11 is laid on the bottom surface of the waste disposal site 10. To do.

According to the method for detecting a defective portion of the water-blocking sheet 11 of this embodiment, as shown in FIG. 3, first, a predetermined area in which a defective portion is to be detected, for example, a number including a plurality of joint portions 13 is included. An airtight sheet 1 made of synthetic resin such as vinyl chloride covering an area of 10 m × tens of m
5 is laid and the periphery thereof is closely adhered to the water-impervious sheet 11 via, for example, a peelable adhesive, so that the upper surface of the water-impermeable sheet 11 is surrounded by the water-impervious sheet 11 and the airtight sheet 15. A closed space 16 is formed.
Further, the airtight sheet 15 is provided with a ventilation nozzle 21 in advance, and by attaching the pressure resistant hose 17 thereto, the pressure resistant hose 17 communicates with the closed space 16. Further, the pressure-resistant hose 17 is connected to a vacuum pump 18 or a compressor 19, and
A pressure gauge 20 is attached on the way.

After the installation work is completed, the vacuum pump 18 or the compressor 19 is activated,
The closed space 16 is brought into a negative pressure state or a pressurized state. That is, when the vacuum pump 18 is used, the air in the closed space 16 is sucked, and when the compressor 19 is used, the air is fed into the closed space 16 to bring the closed space 16 into the respective pressure states. In addition, the pressure gauge 20 is allowed to stand for a while in this state, and changes in the pressure in the closed space 16 are observed. Then, by detecting the negative pressure or the decrease in the applied pressure, it is found that there is a defective portion in the portion covered with the airtight sheet 15.

When the pressure gauge 20 detects a negative pressure or a decrease in applied pressure, the airtight sheet 1 is
5 is removed, the airtight sheet 15 is attached again over the water-blocking sheet 11 while the area covering the water-blocking sheet 11 is gradually narrowed, and the same detection work is subsequently performed. That is, the airtight sheet 15 is sequentially replaced with a sheet having a smaller area, and the presence or absence of a pressure change is checked while narrowing the area where the detection work is performed, so that the water-blocking sheet 11 is finally removed. The position where the defective portion exists can be accurately specified.

By performing such work over the entire area of the laid water-blocking sheet 11, the defective portion of the water-blocking sheet 11 can be detected before the waste is dumped, and the defective portion can be easily repaired. be able to. In the above embodiment, the sealed space 16 including the joint portion 13 is included.
Although the case where the joint portion 13 is formed has been described, the joint portion 1 is not always necessary when it is not necessary to detect the defective portion of the joint portion 13.
The airtight sheet 15 may not be attached to cover the sheet 3.

In the above embodiment, the case where the defective portion of the water blocking sheet laid at the waste disposal site is detected has been described, but the present invention is not limited to this, and a water hazard of a golf course is provided. , Simple reservoir,
It can also be applied to detect missing parts of the impermeable sheet laid on the bottom of facilities that store water in recesses such as reservoirs and pools, or the impermeable sheet laid around the underground structure. .

[0018]

As described above in detail, according to the method of detecting a defective portion of the water-blocking sheet according to the present invention, the sealed space formed by covering the predetermined area on the upper surface of the water-blocking sheet with the airtight sheet is sucked. Alternatively, with a simple configuration of pressurizing and detecting a change in the pressure state of the closed space, it is possible to easily and quickly detect the presence or absence of a defective portion of the water-blocking sheet at the laying site.

Further, by successively narrowing the area covering the water-blocking sheet with the airtight sheet and continuously checking the presence or absence of the defective portion, the position where the defective portion exists can be easily and accurately specified.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a waste disposal site where a waterproof sheet is laid using the method for detecting a defective portion of the waterproof sheet according to the present invention.

FIG. 2 is an enlarged view of a main part showing a state of laying a waterproof sheet.

FIG. 3 is a cross-sectional view showing an embodiment of a method of detecting a defective portion of a water-blocking sheet according to the present invention.

[Explanation of symbols]

 10 Waste Disposal Site 11 Water Impermeable Sheet 15 Airtight Sheet 16 Sealed Space 17 Pressure Hose 18 Vacuum Pump 19 Compressor 20 Pressure Gauge

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masao Kuroiwa 2-3 Chome, Kandajimachi, Chiyoda-ku, Tokyo Obayashi Corp.

Claims (2)

[Claims] 1. A method of detecting a defective portion of a water impermeable sheet for detecting a defective portion of a laid water impermeable sheet, which comprises covering a predetermined area on an upper surface of the water impermeable sheet with an airtight sheet and The periphery of the sheet is brought into close contact with the upper surface of the impermeable sheet to form a sealed space between the impermeable sheet and the airtight sheet, and the sealed space is suctioned or pressurized, and after the suction or the pressure is applied. A method of detecting a defective portion of a water-blocking sheet, comprising detecting the presence or absence of a defective portion in a portion covered by the airtight sheet by detecting a change in pressure in the closed space. 2. When a defective portion of the water impervious sheet is detected, the presence or absence of the defective portion is continuously detected while successively narrowing the area covering the water impervious sheet by the airtight sheet, The method for detecting a defective portion of a water-blocking sheet according to claim 1, wherein the position is specified.