JPH10286885A - Fault inspecting method of water-impervious sheet joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To elongate the length to be inspected at one time and make it possible to precisely judge the defect part due to the application of a load to a joint by a method wherein an air-permeable flexible hollow cord is provided between the overlapped parts of water-impervious sheets at a joint to the longitudinal direction of the joint so as to evacuate the hollow cord in order to detect the change of the pressure in the cord. SOLUTION: Joining layers 5 and 6 having an interval between each other are arranged between the overlapped parts of the end part of and upside impervious sheet 2 and of that of a downside impervious sheet 3 so as to turn a space surrounded by the upside and downside impervious sheets 2 and 3 and the joining layers 5 and 6 into an airtight passage 4. In the passage 4, an airpermeable flexible hollow cord 8 is interposed freely and movably. Prepared unshaped sealing materials 14 are filled between the joining layers 5 and 6. The inserting pipe 11 of a vacuum pump 10 is inserted in the hollow cord 8 at its end part. The interior of the hollow cord 8 is evacuated so as to read the pressure under a pressure-reduced state in the cord wit a pressure gauge 13 after the elapse of a predetermined period of time. If the change in pressure is indicated, the existence of the defective joining part in the section, in which the inserting pipe is inserted, is revealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of inspecting a water-impervious sheet for defects. More specifically, the present invention relates to a method for accurately inspecting a defective portion of a joint without interrupting a path for inspection even when a load is applied to the joint. It relates to an inspection method that can be determined.

[0002]

2. Description of the Related Art In a landfill type waste disposal site for storing industrial waste and general waste, there is a danger that sewage leaking from the disposal site will penetrate underground and cause environmental pollution.
In order to prevent this, it is mandatory to apply a seepage control to the bottom of the disposal site. There are various types of water-blocking works, but in general, a method of laying a resin-based sheet or rubber-made water-blocking sheet is often adopted from the viewpoint of reliability, safety, workability, and economy. .

[0003] In order to prevent water leakage, a water-blocking sheet is laid on the bottom of a facility for storing water in a depression such as a reservoir, a storage pond, or a pool, in the same manner as a waste disposal site. Further, in an underground structure or the like, a water-blocking sheet may be laid over the structure in order to prevent groundwater from leaking into the structure. And since it is difficult for construction work to cover the bottom of water storage facilities such as waste disposal sites and reservoirs with a large area and the surroundings of structures at one time, it is difficult to construct these waterproof sheets. Construction is being carried out to cover the entire area around waste disposal sites, water storage facilities, and underground structures by joining and integrating on-site using water-impervious sheets.

[0004] However, in such a method of joining the water-blocking sheet on site, there is a case where a joining portion joined at the site may have a joint failure, and there is a problem that sewage or water leaks from a defective portion due to the joint failure. there were. Conventionally, the proper inspection of the joint of the impermeable sheet is performed by performing an adhesion test of the joint by a sampling test, or by injecting air into the unattached part of the impermeable sheet at the construction site and applying a constant pressure for a certain time. After holding, it was evaluated that no outflow of air would occur without the phenomenon of pressure. However, this method is suitable for a waterproof sheet made of synthetic resin such as vinyl chloride, but on the other hand, a sheet having a high elasticity such as rubber has a bonded portion in a sticky state and has a relatively low modulus, so that it has a defect. In some cases, a decrease in pressure may be observed even when no defect occurs, and there is a problem that it is difficult to accurately determine a defective portion.

As another method, there is a method in which an ultrasonic inspection machine is brought into contact with a bonding portion to detect a defective portion. However, this method is also suitable for a resin sheet which has been bonded by fusion. However, there is a problem that the method cannot be applied to a rubber sheet in which a foreign adhesive layer is interposed.
In order to improve these problems, the present applicant has disclosed a needle provided with a smoke blower at an unattached portion of a previously formed impermeable sheet joint as disclosed in Japanese Patent Publication No. 7-37072. A method of observing a place where the smoke flows out of the sheet after inserting the portion and feeding the smoke through the through hole of the needle portion has been proposed.

[0006]

However, in the case of sending gas such as air or smoke into a narrow passage, the pressure is a force in a direction in which a joint portion of the impermeable sheet is peeled off. The size of the pressure was limited because of the possibility of the part being peeled off. The limitation of the pressure leads to the limitation of the length of the joint that can be inspected in one operation, and the efficiency of the operation cannot be improved beyond a certain limit. Further, there is also a problem that the joint portion is pressed down by the weight of the impermeable sheet or by human walking at the time of construction, thereby blocking a passage for inspection.

Therefore, the present invention has a longer length that can be inspected in a single operation, and does not block a passage for inspection even if a load is applied to the joint. It is an object of the present invention to provide a method for inspecting a joint of a seepage control sheet that can be judged.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, the water-impervious sheet is overlapped between the water-impervious sheet joints in the water-impervious sheet joint, and furthermore, in the longitudinal direction of the joint. A water-impervious sheet for inspecting a joint of a water-impervious sheet by interposing a stretchable hollow cord having air permeability, depressurizing the inside of the hollow cord, and detecting a change in pressure in the hollow cord after the decompression. In the defect inspection method of the sheet joint, there is no interruption of the inspection passage even if a load is applied to the joint because the above-mentioned hollow cord is used, and the ground ground because the hollow cord has elasticity This can sufficiently follow the movement of the joint and the movement of the joint, so that the defect inspection can be reliably performed without cutting. Furthermore, compared with the method of pressurizing the inside of the passage, there is no risk of peeling of the joint, and the pressure can be reduced with a large pressure difference. Can be made longer, and the efficiency of inspection work can be improved.

In the invention according to the second aspect of the present invention, two joining layers are arranged and interposed in parallel in the longitudinal direction of the joint at intervals of the water-impervious sheet at the joint of the water-impervious sheet at intervals. The present invention relates to a method for inspecting a joint of a seepage control sheet installed in a passage formed by the above method.

In the invention according to claim 3 of the present application, the inside of the hollow string is depressurized, and after confirming that there is a change in pressure, the inside of the hollow string is pressurized, and an abnormality in the swollen state of the joint is visually confirmed. By this, the airtightness is improved by the hollow string specifying the defective portion being installed in parallel in the longitudinal direction of the joint with a space between the two joining layers between the overlaps of the impermeable sheets at the joint of the impermeable sheet. In the defect inspection method of the impermeable sheet joints installed in the secured passage and installed in the longitudinal direction, the pressure in the passage is reduced, and after confirming that the pressure fluctuates, the pressure in the passage is increased, By visually confirming the abnormality of the swelling state of the joint, the defective portion can be specified.

In the invention according to claim 4 of the present application, the inside of the hollow cord is depressurized, and after confirming that the pressure fluctuates, soap water is applied to the joint to pressurize the inside of the hollow cord to generate bubbles. In the defect inspection method of the water-impervious sheet joint that identifies the defect location by visually checking the location, an efficient method that specifies the section having the defect location and the defect location in the section in each situation In other words, the inspection of the defective portion can be completed quickly and easily comprehensively.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a joint portion of a waterproof sheet used in the defect inspection method of the present invention.
Here, in the joint portion 1, the end of the upper water-impervious sheet 2 and the end of the lower water-impervious sheet 3 are overlapped, and two joining layers 5 and 6 having a thickness equal to each other are arranged at intervals between the overlaps. A space surrounded by the upper and lower water-impervious sheets 2 and 3 and the two joining layers 5 and 6 is formed as an airtight passage 4.
The surface of the obtained joint has a slight stepped portion 7. In this passage 4, a stretchable hollow cord 8 having air permeability is movably interposed, so that even if a load is applied to the joint 1, the passage 4 for inspection is not interrupted, In addition, even if the joining portion 1 is extended due to the movement of the base, the hollow cord 8 follows the same, so that the hollow cord 8 is not cut and can be reliably inspected.

FIG. 2 is a cross-sectional view of another water-impervious sheet joint used in the defect inspection method of the present invention. In this joint 1, the end of the upper water-impervious sheet 2 and the lower water-impervious sheet 3 are joined. The end portions are overlapped, and two joining layers 5 and 6 having different thicknesses are arranged and interposed at intervals between the overlapping portions, and are provided on the upper and lower water-impervious sheets 2 and 3 and the two joining layers 5 and 6. The enclosed space is an airtight passage 4 having a smaller volume than the space shown in FIG. When depressurizing the passage 4 having a reduced volume, the time can be reduced. In this passage 4, a stretchable hollow cord 8 having air permeability is movably interposed.

Although the two different joining layers 5 and 6 are as described above, the joining layer 5 having a small thickness may be joined by an adhesive or heat fusion.

FIG. 3 is a cross-sectional view of still another impermeable sheet joint used in the defect inspection method of the present invention, wherein the end of the upper impermeable sheet 2 and the end of the lower impermeable sheet 3 are overlapped. Two bonding layers 5 and 6 having different thicknesses are arranged between the bonded portions 1 at an interval. The low thickness bonding layer 5 consists only of the applied adhesive, while the high thickness bonding layer 6 comprises polyethylene, polyamide, polyester,
Sealing material 6a made of synthetic resin film such as vinyl chloride
To form an airtight passage 4 having a reduced volume. The sealing material 6a is not a bonding agent but forms a passage 4 having a predetermined space between the joints 1. The volume of the passage 4 can be adjusted by changing the thickness of the sealing material 6a. In the passage 4, a stretchable hollow cord 8 having air permeability is also movably interposed.

In the embodiment shown in FIG. 4, a stretchable hollow cord 8 having air permeability is buried in the passage 4 in a completely filled state, and the position is fixed.

The hollow cord 8 is a hollow knitted fabric having a diameter of 1 to 4 mm made of a nylon fiber, a polypropylene fiber, a polyester fiber, or a metal fiber. . The tensile elastic modulus of the hollow cord 8 is preferably in the range of 0.1 to 1 kgf in order to follow the movement of the substrate.

The material used for the bonding layers 5 and 6 is not particularly limited. For example, when the water-blocking sheet is a vulcanized rubber sheet, a natural vulcanized rubber tape or a synthetic resin film which is vulcanized at ambient temperature is used. When the water-shielding sheet is made of a thermoplastic resin, a thermoplastic elastomer, or the like, it may be joined by heat fusion. As the liquid adhesive, a natural vulcanization type, a two-liquid mixture type, or a butyl rubber adhesive is used. In particular, in the present invention, it is preferable to use a naturally vulcanized rubber tape having improved workability and having a sufficient bonding force when the water shielding sheet is bonded on site. The thickness of this tape is 0.5 to 3.0 mm and the width is 70 to
Two types of tape having a width of 200 mm and a narrow tape of 10 to 70 mm are used.

The water shielding sheets 2 and 3 used here are, for example, ethylene propylene terpolymer (EP
T), butyl rubber, or vulcanized rubber composed of a blend of EPT and IIR, thermoplastic resin such as vinyl chloride, vinyl acetate, etc., thermoplastic elastomer, or rubberized asphalt.

FIG. 5 shows an example of the vacuum pump 9 used in the method of the present invention. The insertion tube 11 made of a needle or a needle is sealed and inserted so as not to cause leakage. The insertion position may be the end of the section of the joint 1 and the insertion tube 11
If is a needle, it may be an arbitrary position on the way. The pump body 10 and the insertion pipe 11 are connected by a hose 12, and a pressure gauge 13 is arranged at an intermediate position.

The joint 1 provided as described above is used to inspect a defective portion of the joint. That is, in order to perform such an inspection method, first, the joining portion is divided into one section of a predetermined length, for example, about several meters to several tens of meters along the extending direction of the joining portion, and both ends are provided with airtightness. The irregular-shaped sealing material 14 is filled between the bonding layers 5 and 6, or is sandwiched by a grip plier (not shown). At the end of the section, as shown in FIG. 6, an insertion pipe 11 of a vacuum pump 9 for reducing the pressure is inserted into the hollow cord 8.

Then, the inside of the hollow string 8 is sucked by the vacuum pump 9 to reduce the pressure. After a lapse of a predetermined time in a depressurized state, the pressure gauge 13 is read, and if a change occurs in the pressure, it is known that there is a joint defect portion somewhere in the section.

The width and height having airtightness are determined by the arrangement and thickness of the bonding layers 5 and 6, and the thickness of the bonding layers 5 and 6 is 0.5 to 3.0 mm because If it is less than 0.5 mm, the bonding strength is insufficient, and if it is more than 3.0 mm, the step of the bonding portion 1 with the bonding layers 5 and 6 interposed therebetween is undesirably large.

The reduced pressure is in the range of 10 to 60 cmHg. If the value is smaller than 10 cmHg, the pressure difference from the atmospheric pressure is small, so that it is difficult to detect a change in pressure even if the joint 1 has a defect. Waterproof sheets 2, 3
Is undesirably elongated.

As described above, if a method of inspecting a defective portion of the joint by reducing the pressure in the hollow cord 8 provided in the joint 1 is adopted, conventionally, the pressure is not increased due to fear of peeling of the joint. Since the maximum length of one inspection section is about 15 m at the maximum, it can be increased to 100 m or more, so that inspection efficiency can be improved. When the section having the defective portion can be specified, the process proceeds to a step of checking which portion of the section has the defective portion.

One method for identifying a defective portion is to use a passage 4 of the joint 1 in a section including the defective portion.
The inside is pressurized so that the passage 4 expands when viewed from the outside. Then, the state of the joint 1 is observed, and as shown in FIG.
Is found to be a defective part.

As another method, a soap solution is applied to the entire joint 1 in the section including the defective portion, and the inside of the passage 4 is pressurized. Then, by observing the state of the joint 1 and finding a location where bubbles of soapy water are generated, it is known that the location is a defective location. In order to pressurize the inside of the passage 4, it is necessary to use a pump for pressurization. However, the above-described vacuum pump may be replaced with a pump for pressurization or may be switched between decompression and pressurization from the beginning. A pump may be used.

[0028]

Next, a specific example of the inspection method of the present invention will be described.
The same thickness and width as the natural vulcanization type adhesive tape with a thickness of 1.0 to 1.5 mm and a width of 100 mm are attached to the joint (150 mm in width) of the impermeable sheet mainly composed of EPT having a thickness of 1.5 mm. 50mm natural vulcanization type adhesive tape with width 20
mm, and a hollow string made of polypropylene fiber having a diameter of about 2.0 mm was interposed in a state close to the end face of the wide adhesive tape to form a passage in the space.

Then, the joint was pressed by a roller with a rolling pressure (linear pressure: 0.5 kg / cm) to obtain a joint having a length of 15 m. Both ends in the length direction of the passage were sealed with an irregular sealing material, and at the same time, a defective portion was intentionally provided so that the outside of the sheet could communicate with the passage. An inspection for identifying a defective portion was performed by a method of pressurizing and then pressurizing the joint.

The insertion tube of the pump for reducing and increasing the pressure is attached to the end of the hollow cord at the joint, and the defective portion is provided at a position 13 m away from the end. Both reduced pressure and increased pressure were performed while changing the pressure.

As a result, if the pressure is excessively increased, the joint is peeled off, so that the pressure can be increased up to only about 0.01 kg / cm ² , so that the time until the entire length of the joint becomes uniform pressure is reduced. As a result, the inspection time becomes significantly longer than the method of reducing the pressure. Also, when the pressure is reduced to less than 10 cmHg, the pressure difference from the atmospheric pressure is so small that it becomes difficult to detect a change in pressure even if there is a defect in the joint. If the pressure reduction is greater than 60 cmHg, the water impermeable sheet is unnecessarily stretched at the joint, which is not preferable.

[0032]

As described above, according to the first and second aspects of the present invention, it is possible to expand and contract air-permeable sheets in the longitudinal direction of the joint between the water-impervious sheets at the joint thereof. A method of inspecting the defect of the impermeable sheet joint by interposing a hollow cord, depressurizing the inside of the hollow cord, and detecting a pressure change in the hollow cord after the decompression, Even if a load is applied to the joint, it does not block the inspection passage, and since the hollow cord has elasticity, it can sufficiently follow the movement of the ground and the joint, so it is cut. Therefore, the defect inspection can be performed reliably. Furthermore, compared with the method of pressurizing the inside of the passage, there is no risk of peeling of the joint, and the pressure can be reduced with a large pressure difference. Can be made longer, and the efficiency of inspection work can be improved.

According to the third aspect of the present invention, the inside of the hollow cord is depressurized, and after confirming that the pressure fluctuates, the inside of the hollow cord is pressurized, and the abnormal state of the bulging state of the joint is visually confirmed. By this, the airtightness is improved by the hollow string specifying the defective portion being installed in parallel in the longitudinal direction of the joint with a space between the two joining layers between the overlaps of the impermeable sheets at the joint of the impermeable sheet. In the defect inspection method of the impermeable sheet joints installed in the secured passage and installed in the longitudinal direction, the pressure in the passage is reduced, and after confirming that the pressure fluctuates, the pressure in the passage is increased, By visually confirming the abnormality of the swelling state of the joint, the defective portion can be specified.

In the invention according to claim 4 of the present application, the inside of the hollow string is depressurized, and after confirming that the pressure fluctuates, soap water is applied to the joint to pressurize the inside of the hollow string to generate bubbles. In the defect inspection method of the impermeable sheet joint to identify the defective portion by visually confirming, the identification of the section having the defective section and the identification of the defective section in the section are efficient in each situation. It can be said that the method is adopted, and the inspection of the defective portion can be completed quickly and easily comprehensively.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a joint part of a seepage control sheet used in a defect inspection method of the present invention.

FIG. 2 is a cross-sectional view of another waterproof sheet joint used in the defect inspection method of the present invention.

FIG. 3 is a sectional view of still another impermeable sheet joint used in the defect inspection method of the present invention.

FIG. 4 is a sectional view of still another impermeable sheet joining portion used in the defect inspection method of the present invention.

FIG. 5 is a perspective view of a pump used for depressurizing an airtight passage.

FIG. 6 is a plan view showing a state where the inspection method of the present invention is performed.

FIG. 7 is a cross-sectional perspective view showing an abnormal portion of a water-impervious sheet joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joining part 2 Waterproof sheet 3 Waterproof sheet 4 Passage 5 Joining layer 6 Joining layer 6a Sealing material 8 Hollow string 9 Vacuum pump 10 Pump body 11 Insertion pipe 12 Hose 13 Pressure gauge 14 Irregular sealing material 15 Defect location

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI // B29L 7:00

Claims (4)

[Claims] 1. A stretchable hollow cord having air permeability in the longitudinal direction of a joint between superposed water-impervious sheets at a joint part of a waterproof sheet, and the inside of the hollow cord is decompressed. A defect inspection method for a water-impervious sheet joint, wherein a defect in the water-impervious sheet joint is inspected by detecting a change in pressure in the hollow cord later. 2. A passage formed by arranging two joining layers in parallel in the longitudinal direction of the joint at an interval between overlapping of the impermeable sheets at the joint of the impermeable sheet, with the hollow cord being provided between the superimposed sheets. The method for inspecting a joint of a water-impervious sheet according to claim 1, wherein the defect is installed in a joint. 3. The inside of the hollow cord is depressurized, and after confirming that the pressure fluctuates, the inside of the hollow cord is pressurized, and an abnormality in the swelling state of the joint is visually confirmed to identify a defective portion. The defect inspection method for a water-impervious sheet joint according to claim 1 or 2. 4. After depressurizing the inside of the hollow cord and confirming that the pressure fluctuates, apply a soapy water to the joint and pressurize the inside of the hollow cord, and visually confirm the generation of bubbles by checking the occurrence of bubbles. The method for inspecting a joint of a waterproof sheet according to claim 1, wherein the location is specified.