JP2008107338A - Inspection method of sealing sheet joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint method of sealing sheet which can depressurize inside ventilation passage to seal defect on the lower joint, if any. <P>SOLUTION: In this method, unvulcanized rubber-made adhesive tapes 4 and 5 are double-arranged with a space left between each of sealing sheets 1, 2 to be lap-adhered on the joint 3 of these sealing sheets to form the ventilation passage 6 between the two rows of adhesive tapes 4 and 5 with the sealant 7 arranged outside the adhesive tape 4 to be allocated on the sheet end which at least comes to base G side when lapped, thus depressurizing inside the above ventilation passage 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for inspecting a water shielding sheet joint, and more specifically, a water shielding that can be closed during inspection if it is a defect due to the presence of sheet wrinkles or small foreign matter at the joint. The present invention relates to a method for inspecting a sheet joint.

  In a landfill-type waste disposal site where industrial waste and general waste are discarded and stored, there is a risk that sewage leaking from the disposal site may penetrate into the basement and cause environmental pollution. In addition, it is obliged to impose a water barrier on the bottom of the disposal site. There are various types of impermeable works, but in general, a method of laying a resin sheet or a rubber impermeable sheet is often adopted from the viewpoints of reliability, safety, workability, and economy. .

  In order to prevent water leakage, a water shielding sheet is laid on the bottom surface of a facility that stores water in a recess such as a reservoir, a reservoir, or a pool. Furthermore, in underground structures and the like, a water shielding sheet may be laid over the structure in order to prevent groundwater from leaking into the structure. And since these water-impervious sheets are difficult in construction, it is difficult to cover the bottom of a water storage facility such as a waste disposal site or a reservoir having a vast area or around the structure with a single water-impervious sheet at a time. 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-proof sheets.

  However, in the method of joining such a water shielding sheet in the field, there is a case in which a joint failure occurs in the joint part joined in the field, and there is a problem that sewage or stored water leaks from a defective part due to this joint failure. Conventionally, the suitability inspection of the joint part of the water shielding sheet has been performed by performing an adhesion test on the joint part by a sampling test, or by injecting air into the unattached part of the water shielding sheet joint part at the construction site, and maintaining a constant pressure for a certain period of time. After holding, it was rated as no air outflow without a pressure drop. However, this method is suitable for water shielding sheets made of synthetic resin such as vinyl chloride, but in the case of rubber-rich sheets such as rubber, the joint is in a sticky state and has a relatively low modulus. There is a problem that a decrease in pressure may be recognized even if no defect occurs, and it is difficult to accurately determine the defective portion.

  As another method, there is a method in which an ultrasonic inspection device is brought into contact with the joining portion to detect a defective portion, but this method is also suitable for a resin sheet that is joined by fusion bonding. In the case of a rubber sheet in which a foreign adhesive layer is interposed, there is a problem that it cannot be applied. Further, in order to improve these problems, the present applicant inserts a needle part equipped with a smoke blower into a non-attached part of a pre-made water shielding sheet joint part as disclosed in Patent Document 1. Then, after sending smoke from the through hole of the needle part, a method for observing the outflow location of the smoke to the outside of the sheet was proposed.

  Moreover, in patent document 2, in the joining of the water-impervious sheets, a defective portion is detected in the joint portion by detecting a change in pressure in the vent passage while forming a vent passage in the joint portion and reducing the pressure in the vent passage. A method for inspecting for leaks is disclosed.

  You can also inspect by pressurizing the inside of the joint, but if you apply pressure, it takes a force in the direction to peel off the bonded joint, so the pressure can not be raised so much and it is inspected in one operation There was a limit to the length of joints that could be made. However, by reducing the pressure in the air passage, there is no risk of peeling the joint, so the pressure can be greatly reduced, and the length of the joint that can be inspected once can be set longer, thus increasing the efficiency of the inspection work. be able to.

Japanese Patent Publication No. 7-37072 Japanese Patent Laid-Open No. 10-67050

  As described above, by adopting a method of monitoring the pressure fluctuation by pressurizing or depressurizing the inside of the air passage formed at the joint, defects in the joint can be found in advance, and finally there is no shielding failure. It can be an aqueous layer.

  However, for example, there is a gap between the water-impervious sheet and the bonding tape, resulting in poor bonding because the sheet may be folded or wrinkled during manufacture of the water-impervious sheet or when wound on a roll. Will occur. Of the two layers of bonding tape, the problem between the sheet stacked on the upper side and the bonding tape disposed at the end is in a place where it can be seen from the surface side of the sheet. By applying or patching, inspection can proceed while eliminating defects, but defects between the sheet stacked below the joint and the joint tape placed at the end are the sheet surface Since it cannot be seen from the side, it is difficult to repair even if there is a bonding failure. Normally, if a leak is found due to poor bonding, the defective part is repaired and inspected again until the defective part disappears, but the inspection is repeated, but there is a defect between the sheet stacked under the joint and the bonding tape. In some cases, even if the inside of the air passage is decompressed and the joint is inspected to detect the presence of a joint failure, the repair is difficult, and at that time, the inspection / repair work cannot be performed.

  Therefore, an object of the present invention is to provide a water shielding sheet joining method capable of closing a defect by decompressing the inside of the air passage even when the joint on the lower side of the joint is defective.

  In order to achieve the above object, in claim 1 of the present invention, in the method for inspecting leakage at a joint portion where the water shielding sheets are joined together, the water shielding material which is joined to the joint portion of the water shielding sheet in an overlapping manner. By arranging two rows of unvulcanized rubber bonding tapes between the sheets at an interval to form an air passage between the two rows of bonding tapes, at least the sheet end that comes to the ground side when they are stacked The inside of the ventilation path is depressurized in a state where a sealing material is arranged outside the bonding tape arranged in the section.

  In claim 2, the inside of the air passage is depressurized to check for pressure fluctuations. If there is a fluctuation, the inside of the air passage is pressurized, and an abnormality in the swollen state of the joint is visually confirmed. It is set as the test | inspection method of the water-shielding sheet junction part of Claim 1 which specifies a location.

  In claim 3, the inside of the air passage is depressurized to check for pressure fluctuations, and if there is a fluctuation, a colored gas is injected into the air passage to visually check for leakage of the colored gas. It is set as the test | inspection method of the water-shielding sheet junction part of Claim 1 which specifies a location.

  In claim 4, the inside of the air passage is depressurized to check for pressure fluctuations. If there is a fluctuation, the inside of the air passage is pressurized with soap water applied to the joint and the occurrence of bubbles is visually confirmed. The inspection method for the water shielding sheet joint portion according to claim 1, wherein the defective portion is specified by doing so.

  In Claim 5, it is set as the test | inspection method of the water-shielding sheet junction part of Claims 1-4 which arrange | positions a hollow string in a ventilation path.

  In Claim 6, it is set as the test | inspection method of the water-shielding sheet junction part of Claims 1-5 formed by extending and bonding a joining tape on the sheet | seat surface side of a junction part.

  In Claim 7, The sealing material arrange | positioned on the outer side of a joining tape is the range whose width is 5-20 mm, and thickness is the range which is 0.5-3 mm, The test | inspection method of the water shielding sheet of Claims 1-6 It is said.

  In claim 1, among the joining tapes arranged in two rows in the joining portion where the waterproof sheets are overlapped with each other, a sealing material is arranged on the outside of the joining tape arranged on the end portion of the sheet on the base side. Even if there is a poorly bonded portion between the sheet and the bonding tape, if it is a small defective portion, the sealing material disposed outside the bonding tape is sucked by reducing the pressure of the air passage between the two rows of bonding tape. As a result, it is possible to enter the poorly bonded portion and close the hole. Therefore, there is no problem as long as the bonding failure is small enough to occur due to sheet folding.

  In claim 2, the inside of the air passage is left in a depressurized state, and when the pressure fluctuates, the inside of the air passage is pressurized and the abnormality is identified by visually confirming the abnormality in the joint. The location can be specified as well as the presence or absence of.

  Even if the pressure passage fluctuates by leaving the air passage in a decompressed state in claim 3, the air passage is pressurized with colored gas, and it is defective by visually confirming that the colored gas is discharged from the defective portion. The location is specified, and the failure location can be detected and specified very easily.

  Similarly, claim 4 also specifies a defective portion by applying soap water to pressurize the inside of the air passage and visually confirming the generation of bubbles after specifying the defective portion of the joint. The location can be detected and specified very easily.

  In Claim 5, the hollow string is arrange | positioned in an air flow path, and it prevents that an air flow path is obstruct | occluded when a load is applied to a junction part, or it is obstruct | occluded by decompressing the inside of an air flow path. Can do.

  According to the sixth aspect of the present invention, the bonding tape is further stretched on the surface side of the bonding portion, so that the confidentiality of the air passage can be made more complete.

  According to the seventh aspect, the width and thickness of the sealing material are limited to a predetermined size, so that a more reliable sealing effect can be obtained and a step at the joint portion does not become too large.

  Hereinafter, the inspection method of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a method for joining a water shielding sheet to be inspected by the inspection method of the present invention.

  For example, as shown in FIG. 2, water-impervious sheets 1 and 2 are disposed on a base G of a waste disposal site formed from a bottom surface T and a slope N, and industrial wastes are disposed thereon. In addition, the sewage from the waste does not soak into the base G. In order to spread the water-impervious sheets 1 and 2 over the entire surface of the base G, the water-impervious sheets 1 are joined to each other so as to cover the entire surface of the base G.

  The joint 3 between the water-impervious sheets has a part that is previously joined in the factory and then brought to the site, but there are many parts to be joined at the site, paying sufficient attention to the water tightness of the joint. Water leakage from the joint 3 must be prevented. Therefore, the present invention relates to an inspection method for identifying the presence or absence of a defective joint location after joining the end portions of the water shielding sheets.

  In the joining part 3, the end part of the upper water-impervious sheet 1 and the end part of the lower water-impervious sheet 2 are overlapped, and two joining tapes 4 and 5 having the same thickness are placed between the overlapped end parts. The air passage 6 having airtightness surrounded by the upper and lower water shielding sheets 2 and 3 and the two joining tapes 4 and 5 is formed. The ventilation path 6 is usually partitioned in units of a predetermined length, and inspection is performed for each section.

  The sealing material 7 is arranged on the outer side of the bonding tape 4 arranged at the end of the lower water-impervious sheet among the bonding tape forming the air passage 6. In this state, the inside of the air passage 6 is decompressed and left to stand, and the pressure change in the air passage 6 is observed. If there is a fluctuation in pressure, it can be determined that there is a defective portion somewhere in the joint portion 3 and that air has entered the vent passage 6 that has been depressurized. At this time, it is possible to stretch the bonding tape 8 not only on the sealing material 7 but also on the surface side of the bonding portion 3.

  If there is no defective portion, the inspection of the section is finished, but if there is a defective portion, compressed air is sent into the air passage 6 and pressurized so that the air passage 6 is inflated when seen from the outside. If the joint part 3 is visually confirmed and an abnormal part 9 where the part that should have been bonded is swelled as shown in FIG. 4 is found, for example, the part is known to be a defective part and the place can be specified. .

  If the defective part can be identified, the part is repaired by a method such as reheating or adding the part again. When the repair is completed, the section including the defective portion of the air passage 6 is decompressed again to confirm the presence or absence of the defective portion. If there is a defective portion, pressurize the inside of the air passage 6 to identify the defective portion, repeat such a process, and perform inspection in all sections of the partitioned air passage 6 so that there is no defective portion. 3 can be obtained.

  In such an inspection, if the bonding between the bonding tape 5 and the water shielding sheets 1 and 2 disposed at the end of the upper water shielding sheet 1 is poor, the state of the defective portion should be visually confirmed from the surface of the water shielding sheet. Therefore, the location can be easily identified, and repair work is possible in most cases. However, when the bonding tape 4 disposed at the end of the lower water-impervious sheet 2 and the water-impermeable sheets 1 and 2 are poorly bonded, it is difficult to identify the defective part and repair work is almost impossible. . If neither the defective part nor the repair can be performed, the result of failing for the section is determined. In some cases, it is necessary to repeat the joining from the beginning, for example, by replacing the water shielding sheet.

  Therefore, in the present invention, the sealing material 7 is arranged outside the bonding tape 4, and when the pressure in the first air passage 6 is depressurized in order to investigate the presence or absence of a defective portion, the depressurization is performed to a certain extent. The sealing material 7 can flow into the hole and block the hole. Until now, in the inspection to confirm the presence or absence of a defective portion by reducing the pressure of the air passage 6 as described above, the bonding tape 4 and the water shielding sheet 1 at the end of the water shielding sheet 2 superimposed on the lower side. In the case where a bonding failure has occurred between the two, it is difficult to repair and the failure has been confirmed. it can.

  What can be used as the water shielding sheet in the present invention is, for example, a vulcanized rubber made of ethylene / propylene / diene monomer, butyl rubber, or a blend thereof, a thermoplastic resin such as vinyl chloride and vinyl acetate, a thermoplastic elastomer, Examples include rubberized asphalt.

  As the adhesive tapes 4 and 5, natural vulcanized rubber tapes or synthetic resin tapes can be used. When the water shielding sheet is a thermoplastic resin, a thermoplastic elastomer, etc., they may be joined by thermal fusion. . Moreover, as a liquid adhesive, a natural vulcanization type, a two-component mixed type, and a butyl rubber adhesive are used. In particular, in the present invention, it is preferable to use a natural vulcanization type rubber tape that has improved workability and has a sufficient joining force when joining the water shielding sheet on site. The thickness of this tape is 0.5 to 3.0 mm, and the width is, for example, a wide tape having a width of 70 to 200 mm and a narrow tape of 10 to 70 mm. The width and height of the air passage 6 are determined by the arrangement and thickness of the bonding tapes 4 and 5, and the thickness of the bonding tapes 4 and 5 is set to 0.5 to 3.0. The strength tends to be insufficient, and if it exceeds 3.0 mm, the level difference of the joint 3 becomes large, which is not preferable. Since the bonding tape 8 that is stretched on the surface of the bonding portion 3 is bonded only on one side, a two-layer tape in which a rubber sheet is laminated on the surface side is used. This additional bonding tape 8 may be provided prior to the inspection, or may be used in such a way that additional reinforcement is applied to the inspection tape that has passed the inspection.

  As the sealing material 7, silicon-based, modified silicon-based, butyl rubber-based, urethane-based, thiocol-based, polysulfide-based, and polyisobutylene-based materials can be used. For example, butyl rubber, halogenated butyl rubber, ethylene propylene terpolymer (EPT), etc. The rubber composition which mix | blended the filler, the softening material, the adhesive material, etc. can be mentioned. It is necessary to maintain a certain degree of shape and to exhibit sufficient sealing properties, and those having a penetration (1/10 mm, 25 ° C.) in the range of 200 to 600 are preferable. If the penetration (1/10 mm, 25 ° C.) is less than 200, there is a problem that the sealing material flows at the time of rolling, and if it exceeds 600, it becomes difficult to flow and flows even if there is a defective portion at the joint. Since it cannot be closed and does not close the hole, the purpose of disposing the sealing material 7 cannot be achieved.

  The sealing material 7 preferably has a width of 5 to 20 mm and a thickness of 0.5 to 3 mm. If the width is less than 5 mm or the thickness is less than 0.5 mm, the sealability may not be sufficiently secured, and the object of the present invention may not be achieved. Moreover, even if the width exceeds 20 mm, the sealing performance obtained does not change much, and only the width of the joint is widened. A thickness exceeding 3 mm is not preferable because it leads to an increase in the level difference of the joint 3.

  At the beginning of the inspection, the pressure in the air passage 6 is reduced using the vacuum pump P. An example of the vacuum pump P is as shown in FIG. The insertion tube 11 made of a hose, a metal hollow rod, a needle or the like is sealed and inserted so as not to leak. The insertion position may be the end of the partitioned ventilation path 6 or may be an arbitrary position. The pump body 10 and the insertion pipe are connected by a hose 12 and a pressure gauge 13 is disposed at an intermediate position.

  In order to inspect the joint with the above configuration, first, as shown in FIG. 6, the joint is divided into a plurality of sections with a predetermined length (for example, about several meters to several tens of meters) along the extending direction of the joint. In order to provide airtightness, the both ends are filled with an indeterminate sealing material 14 between two rows of joining tapes 6 or are sandwiched using clip pliers or the like. At the end of the compartment, an insertion tube 11 connected to a vacuum pump for decompressing the airtight passage 6 is inserted.

  And the vacuum pump P is operated and the inside of the ventilation path 6 is pressure-reduced. The reduced pressure is in the range of 10 to 60 cmHg. If the pressure is less than 10 cmHg, the pressure difference from the atmospheric pressure is small, so even if there is a defect in the joint, it is difficult to detect pressure fluctuations. If the pressure is greater than 60 cmHg, the water shielding sheet is greatly stretched by the decompression force at the joint. Therefore, it is not preferable.

  When the pressure is reduced and left for 1 to 3 minutes, the presence or absence of fluctuations in the atmospheric pressure is confirmed, and if there are fluctuations of a certain degree or more, it can be determined that there is a defect in the section where the inspection is being performed. When there is no defective part, it moves to the inspection to the next section, and when it is determined that there is a defect, compressed air is sent into the air passage 6 of the section to pressurize the inside of the air passage 6. Pressurization of about 0.05 to 0.10 atm is performed, and the state of the air passage 6 in the compartment is observed from the surface. Then, by finding a portion where an abnormality is seen, such as a swollen portion of the joint 3, it is possible to identify a place where a defect such as a joint failure is present.

  Although the method of observing the abnormality of the junction 6 by pressurizing the inside of the air passage may be specified to identify the defective part, the colored gas leaks out from there if a hole is opened by sending colored gas such as smoke. Since it comes in, the pressurizing force is small and there is an advantage that it is easy to check. Furthermore, since bubbles are generated when air leaks from the defective portion by applying soap water to the joint portion, the defective portion can be identified more easily.

  Further, by arranging the hollow string 15 in the air passage 6 as shown in FIG. 7, air passes even when the inside of the air passage 6 is depressurized or pressurized from the surface of the air passage 6. Not only can a sufficient space be secured, a longer section can be depressurized with the same vacuum pump, and specifically, a section of 100 m or more can be formed. Therefore, the reliability of inspection can be increased and the efficiency can be improved.

  As the hollow string 15, it is preferable to use a hollow knitted fabric having a diameter of about 1 to 4 mm made of nylon fiber, polypropylene fiber, polyester fiber, or metal fiber. It also has stretchability in the longitudinal direction, and can follow the movement of the substrate.

  As described above, in the method of inspecting the joint portion by arranging two rows of the joining tape at intervals in the joint portion, and forming the air passage and depressurizing the joint tape, the end portion of the water shielding sheet disposed on the base side By placing a sealing material on the outside of a certain bonding tape, it is possible to block the defective portion due to poor bonding, which is usually difficult to repair from the surface side of the water shielding sheet, by flowing the sealing material by reducing the air passage. And the pass rate in the inspection can be significantly increased.

  The present invention relates to a method for inspecting a water-impervious sheet joint, and in particular, it can be closed during inspection if it is a defect due to the presence of sheet wrinkles, small foreign matters, etc. Yes, it can be used as a method for inspecting a water shielding sheet joint.

It is sectional drawing of the junction part of a water-impervious sheet. It is a schematic diagram of a waste disposal site. It is sectional drawing which shows another example of a water shielding sheet junction part. It is a cross-sectional perspective view which shows the abnormal location of a water shielding sheet junction part. It is a perspective view which shows an example of a vacuum pump. It is a top view which shows a mode that the inspection method of this invention is implemented. It is sectional drawing which shows another example of a water shielding sheet junction part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water shielding sheet 2 Water shielding sheet 3 Joining part 4 Joining tape 5 Joining tape 6 Ventilation path 7 Sealing material 8 Joining tape 9 Abnormal part 10 Pump main body 11 Insertion pipe 12 Hose 13 Gauge 14 Amorphous seal 15 Hollow string G Base P Pump

Claims (7)

  In a method for inspecting leakage at a joint portion where water-impervious sheets are joined together, a bonding tape made of unvulcanized rubber is provided between the water-impervious sheets to be joined in an overlapping manner at the joint portion of the water-impervious sheet. By arranging two rows, a ventilation path is formed between the two rows of the bonding tape, and the sealing material is disposed outside the bonding tape to be arranged at the end of the sheet that comes to the base side at least when they are overlapped. A method for inspecting a water-impervious sheet joint, wherein the inside of the air passage is depressurized.   The pressure inside the air passage is depressurized to check the presence or absence of pressure fluctuations. If there is a fluctuation, the inside of the air passage is pressurized, and the abnormality in the swollen state of the joint is visually confirmed to identify the defective part. The inspection method of the water-shielding sheet junction part of claim | item 1.   The pressure in the air passage is reduced to check the presence or absence of pressure fluctuation, and if there is a fluctuation, a colored gas is injected into the air passage and the leakage of the colored gas is visually confirmed to identify a defective portion. The inspection method of the water-shielding sheet junction part of claim | item 1.   Depressurize the inside of the air passage to check the presence or absence of pressure fluctuations. If there is fluctuation, press the inside of the air passage with soap water applied to the joint and visually check the occurrence of bubbles. The method for inspecting a water shielding sheet joint according to claim 1, wherein:   The method for inspecting a water shielding sheet joint according to claim 1, wherein a hollow string is disposed in the air passage.   The method for inspecting a water shielding sheet joined portion according to claim 1, wherein a joining tape is additionally stretched on the sheet surface side of the joined portion.   The sealing material arranged on the outside of the bonding tape has a width of 5 to 20 mm and a thickness of 0.5 to 3 mm.

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