JPH11277027A - Joint part structure of impervious sheet and inspecting method for joint part of impervious sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint part structure of a water barrier sheet which has a sufficient initial fixing force, and can inspect the whole of a bonded part. SOLUTION: In a joint part structure of an impervious sheet, impervious sheets A and B are bonded through a bonding material 2, a joint part 1 between the binding material 2 and the sheets A and B has unbounded parts to form an airtight passage 4, and the airtight passage 4 is provided with a vent 5 which communicates the binding material 2 from the top to the bottom. As a material used as the sheets A and B, EPDM(ethylene-propylene rubber), HDPE (high density polyethylene), LDPE(low density polyethylene), PP(polypropylene), and TPO(thermoplastic olefin) of the like is exemplified. The thickness thereof is set within 0.8-3.0 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a water-impervious sheet for defects, and more particularly, to an inspection method that does not impose a burden on a joint portion and can easily determine the presence or absence of a defect.

[0002]

2. Description of the Related Art In a landfill type waste disposal site for dumping industrial waste and general waste, in order to prevent sewage leaking from the disposal site from penetrating into the underground and causing environmental pollution, the disposal site must be disposed of. It is compulsory to apply a seepage control to the bottom. There are various types of water-blocking works, but a method of laying a resin-made sheet or a rubber-made water-blocking sheet is often adopted in terms 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 recess such as a reservoir, a reservoir, or a pool, in order to prevent water leakage. Further, in an underground structure or the like, a waterproof sheet may be laid over the structure in order to prevent groundwater from leaking into the structure.

[0004] It is difficult to cover these water-impervious sheets at once with a single sheet of water-impervious sheet covering the bottom of a water storage facility such as a waste disposal site or a reservoir with a large area, or the periphery of a structure. For this reason, construction is being performed to cover the entire area around waste disposal sites, water storage facilities, and underground structures by joining and integrating multiple water-impervious sheets on site.

[0005] However, in the 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 portion of the waterproof sheet is performed by performing an adhesive strength test of the joint portion by a sampling test, or at the construction site, as shown in FIG. After arranging the two rows of bonding materials 14 and 15 and injecting air into the airtight passage 16 surrounded by the water-impervious sheet and the two rows of bonding materials, and after maintaining a constant pressure for a certain time, the pressure is reduced. Otherwise, it was evaluated that no air spill had occurred.

[0006] Further, in the case of joining a waterproof sheet using a joining material made of a thermoplastic elastomer, the joining material is fused to one of the waterproof sheets in advance in a factory or the like, and the other is applied on site. It has been performed that the inspection of the joint is limited to only the joint on the side performed at the site.

[0007]

However, the work of arranging the joining material in two rows at the joint portion of the impermeable sheet and forming an airtight passage for inspection with the impermeable sheet and the two rows of the joining material. Is a work that requires carefulness and labor on site work, such as the need to arrange two rows of joining materials at predetermined intervals, and is undesirable because it causes a reduction in work efficiency. In addition, there is another problem that when the joint is pressed, the two rows of the joining material are connected to block the airtight passage, so that the joint cannot be inspected for defects. In addition, in the joining of the water-blocking sheet by natural vulcanization of rubber, the initial adhesive force at the beginning of the joining operation is small, and there is a current situation that it takes time to complete the adhesion.

In addition, a bonding material is heat-sealed to one of the water-blocking sheets in advance at a factory or the like, and the bonding material and the other water-blocking sheet are heat-bonded at the site. In the method of performing only the performed bonding, the bonding portion is not inspected in advance in a factory or the like, and thus cannot be said to be complete.

In view of this, it is conceivable to provide an unfused portion in the joint portion on the side to be thermally fused in advance and to inspect the joint portion on both sides of the joining material. However, the inspection must be performed twice. It has to be a prolonged laying work on site. In view of the above, the present invention can provide a sufficient initial adhesive strength at the site, and can easily provide an airtight passage for inspection without much trouble, and can be joined with two water-impervious sheets to be joined. Provided is a joint structure of a water-impervious sheet such that two joints between the members can be inspected at a time, and a method for inspecting a joint using the same.

[0010]

According to the first aspect of the present invention, in order to attain the above object, in a joint structure of a water impermeable sheet having a structure for inspecting a defect of a joint portion, a joint to be joined is provided. A bonding material is interposed and bonded between the water sheets, and the bonding portion between the bonding material and the water-blocking sheet is
An airtight passage is formed by providing an unbonded portion sandwiched between bonding portions extending in the longitudinal direction of the bonding portion, and at least the airtight passage of the bonding sheet material is provided with a ventilation hole communicating vertically with the bonding material. This is a joint structure of the impermeable sheet.

[0011] With such a joint structure, it is not necessary to arrange two rows of joining materials at a predetermined interval, and only one joining material may be arranged. Since the unfused portion is provided with a vent, it is possible to inspect the upper and lower portions of the bonding material at once.

According to a second aspect of the present invention, a bonding material is interposed between the water-impervious sheets to be bonded to each other and bonded to each other. Forming an airtight passage by providing a non-adhered portion sandwiched between the airtight passages at the joint portion of the water-blocking sheet having a ventilation hole communicating at least above and below the joining material in at least the airtight passage of the joint sheet material After depressurizing or pressurizing the inside, by detecting the fluctuation of the pressure in the airtight passage,
This is an inspection method of a water-impervious sheet joint for inspecting a water-impervious sheet joint.

This is a method for inspecting a joint using the joint structure according to the first aspect, and has the advantage that both the upper and lower portions of the joint can be inspected at once.
Further, in claim 3, after confirming that the pressure fluctuates, soap water is applied to the joint to pressurize the airtight passage, and the occurrence of bubbles is visually checked to identify a defective portion. This is an inspection method for a sheet joint. By adopting such an inspection method, after determining the presence or absence of a defect,
Visual inspection of defects can be performed even on site

[0014]

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 perspective view of a joint structure of a waterproof sheet according to the present invention, FIG. 2 is a sectional view of the joint structure, and FIG. 3 is a perspective view of a joint material. The joining part 1 overlaps the ends of the upper water-impervious sheet A and the lower water-impervious sheet B, and interposes a joining material 2 between the superimposed sheets. The joining between each of the water-impervious sheets A and B and the joining material 2 is performed by heat fusion, and only the joining margin 3 is provided at both ends of the joining portion 1 in the width direction, and the joining portion 1 is provided at the center portion. The airtight passage 4 which is an unjoined portion extends along the longitudinal direction of the airtight passage 4. This structure is adopted both at the two junctions between the upper waterproof sheet A and the joining material 2 and between the lower waterproof sheet B and the joining material 2.

Further, at least a portion corresponding to the airtight passage 4 of the bonding material 2 communicates with the upper and lower sides of the bonding material 2 (both sides of the upper waterproof sheet A and the lower waterproof sheet B). The ventilation holes 5 are provided over the entire length of the bonding material 2 in the longitudinal direction. As an operation for inspecting the presence or absence of a joint failure in the joint part 1 and specifying a joint failure part, the airtight passage 4
The inside is depressurized or pressurized. At this time, the upper and lower sides of the bonding material 2 can be inspected by one operation by providing the ventilation holes 5.

Also, the joining material 2 does not need to be particularly arranged in two rows, and only the both ends in the width direction of the joining material in one row can be fused to the water-impervious sheet only by heating both ends. Not too cumbersome.

In the present invention, materials that can be used as the material of the waterproof sheets A and B are EPDM (ethylene propylene rubber), HDPE (high density polyethylene), LDPE
(Low density polyethylene, PP (polypropylene), TP
O (thermoplastic olefin) and the like.
And the thickness is used in the range of 0.8 to 3.0 mm,
If it is less than 0.8 mm, the water-impervious sheet is likely to be damaged due to insufficient strength, and if it exceeds 3.0 mm, the step at the joint becomes large, which is not preferable in terms of watertightness.

Materials that can be used as the bonding material 2 are as follows:
VLDPE (ultra low density polyethylene), LLDPE (linear low density polyethylene), MDPE (medium density polyethylene), HDPE (high density polyethylene), EVA (ethylene vinyl acetate), EEA (ethylene ethyl acrylate), TPO (thermoplastic) (Olefin) or a thermoplastic elastomer such as an α-olefin copolymer. The thickness of the bonding material 2 is 0.8 to
If it is less than 0.8 mm, there is a problem that insufficient joining force or poor joining is likely to occur, and if it exceeds 3.0 mm, two rows of joining materials 2 are connected. In some cases, there is a problem that the inspection work cannot be performed by closing the airtight passage 4, the volume of the airtight passage 4 becomes too large, and it takes too much time to depressurize and pressurize the inside of the airtight passage 4. There has been a case where the step of the joining portion becomes large and a problem occurs in terms of water tightness.

The vent holes 5 provided in the joining material 2 are not particularly limited in form, but are provided with circular holes having a diameter of, for example, about 3 to 10 mm near the center in the width direction of the joining material 2 at a predetermined pitch in the longitudinal direction. And those in which a large number of small-diameter holes are randomly provided.

In this method, an unjoined portion is provided between the joining material 2 and the water shielding sheets A and B. For example, as shown in FIG. Bonding method using a fusing device having a bonding material 2 or a non-woven fabric or a woven fabric made of a material having a high melting point such as glass fiber on a portion corresponding to an unbonded portion of the bonding material 2 or the water-shielding sheets A and B in advance. Various methods can be adopted, such as a method of fusing only a portion having no nonwoven fabric or the like by heating the whole. Further, the bonding material 2 may be fused to one of the water-impervious sheets in advance at a factory or the like.

The width of the fused portion occupying the width of the joining material 2 is 5 to 5.
The range is 15 mm. If it is less than 5 mm, the joining force may be insufficient, or a joint failure may easily occur.
If it exceeds m, the width of the joining portion becomes too large, which is not preferable.

On the other hand, the width of the hermetic passage 4, which is an unjoined portion, is set to a width of 5 to 25 mm and is less than 5 mm, and the hermetic passage 4 becomes too narrow to insert an insertion tube for inspection. If it exceeds 25 mm, the volume of the airtight passage 4 becomes too large, and it takes too much time to depressurize and pressurize the inside of the airtight passage 4, which is not preferable.

Next, a method of inspecting a joint using the above-described joint structure of the impermeable sheet will be described. The joining part 1 provided by the above method is divided into a predetermined length (for example, about several meters to several tens of meters) along the longitudinal direction of the joining part as shown in FIG. The airtight passage 4 is filled with an indefinite sealing material 6 to provide airtightness, or is sandwiched using a grip plier or the like (not shown). As shown in FIG. 5, the insertion pipe 8 of the pressurizing pump 7 for pressurizing the airtight passage 4 is inserted.

Then, air is blown into the airtight passage 4 by the pressurizing pump 7 to bring the airtight passage 4 into a pressurized state. After a predetermined time has elapsed in the pressurized state, the pressure gauge is read, and if a change occurs in the pressure, it can be seen that there is a joint defect portion somewhere in that section.

In order to check for the presence or absence of a defective portion, the pressure inside the airtight passage 4 may be reduced, and a vacuum pump is used instead of the pressure pump. In the case of pressurization, the pressure cannot be increased so much due to fear of peeling of the joint, so that one test section is shortened. Therefore, from the viewpoint of the efficiency of the test operation, the test with reduced pressure is more preferable.

After the section having the defective portion can be specified, the hermetic passage of the joint in the section including the defective portion is pressurized with a pressure that swells as viewed from the outside. Then, by observing the state of the joining portion and finding an abnormality in the fused portion, it is possible to specify that the portion is a defective portion.

As another method of specifying a defective portion, soapy water is applied to the entire joint portion in the section including the defective portion, and the airtight passage is pressurized. Then, by observing the state of the joint and finding the location where bubbles of soapy water are generated, it can be understood that the location is a defective location.

Although it is necessary to use a vacuum pump to reduce the pressure in the airtight passage, the above-mentioned pressurizing pump may be replaced with a vacuum pump for reducing the pressure, or the pressure may be switched between the reduced pressure and the increased pressure. Alternatively, a pump that can perform the above operation may be used.

[0029]

EXAMPLE Next, the comparison of the initial adhesive strength and the workability when using the joint structure of the water-impervious sheet of the present invention, and the comparison of the inspectable portions of the joints were performed. As an example, a bonding material having a width of 70 mm and a thickness of 1.5 mm made of vulcanized EPDM and polypropylene and a polypropylene made of vulcanized EPDM was used. In the state where 30 mm was taken at both ends in the direction and an unfused portion corresponding to the airtight passage was taken at a width of 10 mm, the impermeable sheet A was used.
Used at the factory. Then, using a fusing device as shown in FIG. 4, the other water-impervious sheet A was welded with 12 mm at both ends in the width direction as a bonding margin and an unfused portion corresponding to an airtight passage with a width of 20 mm. It was put on and joined.

In Comparative Example 1, the water-impervious sheets A and B made of vulcanized EPDM were made of a natural vulcanized rubber tape made of butyl rubber and having a width of 50 mm and a thickness of 1.0 mm as a joining material. In order to provide an airtight passage, the joining materials were arranged in two rows at intervals of 20 mm, and the other impermeable sheet B was overlapped and joined from above.

As Comparative Example 2, the end of the water-impervious sheet B made of vulcanized EPDM was previously formed with a width 7 made of polypropylene.
A bonding material having a thickness of 0 mm and a thickness of 1.5 mm was affixed to the entire surface. Thereafter, an air-tight passage including an unfused portion was provided on the other water-impervious sheet A side in the same manner as in the example, and fusion bonding was performed.

The initial (after 30 minutes) adhesive strength and the aging (after 7 days) adhesive strength between the two water-impervious sheets A and B to be joined and the joining material for the above example and Comparative Examples 1 and 2, respectively. Measure the ease of workability, the bonding material and two impermeable sheets A,
It was confirmed whether or not inspection was possible at two joints between B. Whether the inspection was possible or not was determined on the premise of a method of maintaining the air pressure of 0.5 kgf / cm ² for one minute and confirming the pressure fluctuation. Table 1 shows the results.

[0033]

[Table 1]

From the results shown in Table 1, in the embodiment, the initial adhesive strength and the workability are excellent, and the joint failure can be inspected at the two joints. On the other hand, in Comparative Example 1, the inspection of the bonding failure can be structurally performed at the bonding portion between the bonding material and each of the water-impervious sheets A and B. The result was that the test could not be performed. Further, in Comparative Example 2, although the results of the initial adhesive strength and the workability were equal to or higher than those of the Example, the inspection between the bonding material and the impermeable sheet A could not be performed. It can be seen that there remains anxiety about poor bonding.

[0035]

According to the first aspect of the present invention, in a joint structure between water impermeable sheets having a structure for inspecting joint defects, a bonding material is interposed between the water impermeable sheets to be joined and bonded. An airtight passage is formed by providing an unbonded portion sandwiched between bonding portions extending in the longitudinal direction of the bonding portion in a bonding portion between the bonding material and the water-blocking sheet, and at least the airtightness of the bonding sheet material is provided. A joint structure for a water-blocking sheet, comprising a ventilation hole communicating vertically between joining materials in a sex passage.

With such a joint structure, it is not necessary to arrange two rows of joining materials at a predetermined interval, and only one joining material may be arranged. Since the unfused portion is provided with a vent, it is possible to inspect the upper and lower portions of the bonding material at once.

In the second aspect, a bonding material is interposed between the water-impervious sheets to be bonded, and a bonding portion extending in the longitudinal direction of the bonding portion is provided at the bonding portion between the bonding material and the water-impervious sheet. Forming an airtight passage by providing a non-adhered portion sandwiched between the airtight passages at the joint portion of the water-blocking sheet having a ventilation hole communicating vertically with the joining material in at least the airtight passage of the joint sheet material After depressurizing or pressurizing the inside, by detecting the fluctuation of the pressure in the airtight passage,
This is an inspection method of a water-impervious sheet joint for inspecting a water-impervious sheet joint.

This is a joint inspection method using the joint structure according to the first aspect, and has the advantage that both the upper and lower parts of the joint can be inspected at once.
Further, in claim 3, after confirming that the pressure fluctuates, soap water is applied to the joint to pressurize the airtight passage, and the occurrence of bubbles is visually checked to identify a defective portion. This is an inspection method for a sheet joint.

By adopting such an inspection method,
After determining the presence or absence of a defect, the location of the defect can be visually checked even in the field work

[Brief description of the drawings]

FIG. 1 is a cross-sectional perspective view of a joint structure of a waterproof sheet.

FIG. 2 is a cross-sectional view of a joint structure of a water impermeable sheet.

FIG. 3 is a perspective view of a bonding material.

FIG. 4 is a perspective view of a state where the welding is performed by a fusion device.

FIG. 5 is a plan view showing a state where the inspection method of the present invention is performed.

FIG. 6 is a perspective view of a conventional joint structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joining part 2 Joining material 3 Joining margin 4 Airtight passage 5 Vent hole 6 Irregular sealing material 7 Vacuum pump 8 Insertion pipe

Claims (3)

[Claims] In a joint structure between water impermeable sheets having a structure for inspecting a defect of a joint, a bonding material is interposed between the water impermeable sheets to be joined, and bonded.
An airtight passage is formed in the joint portion by providing an unbonded portion sandwiched between adhesive portions extending in the longitudinal direction of the joint portion, and a ventilation hole communicating vertically with the joining material in at least the airtight passage of the joining sheet material. A joint structure for a water-impervious sheet, comprising: 2. A non-adhered portion sandwiched between fused portions extending in the longitudinal direction of the joint portion is provided at the joint portion with a joining material interposed between the water-impervious sheets to be joined. After forming a gas-tight passage and reducing or pressurizing the inside of the gas-tight passage at the joint portion of the waterproof sheet having a ventilation hole communicating vertically with the joining material in at least the gas-tight passage of the joint sheet material, A method for inspecting a water-impervious sheet joint by detecting a change in pressure in a passageway. 3. After confirming that the pressure fluctuates, a waterproof sheet is applied to the joint to pressurize the airtight passage, and the occurrence of bubbles is visually checked to identify a defective portion. Inspection method for joints.