JP2010054411A - Method for inspection of joint of water shielding sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bonding method of impervious sheets capable of blocking a failure by depressurizing the inside of a water passage, even when a failure exists in bonding on the lower side of a joint. <P>SOLUTION: In a joint 3 between impervious sheets 1, 2, two rows of bonding tapes 4, 5 composed of unvulcanized rubber are arranged at an interval between each impervious sheet to be superposed and bonded, to thereby form a water passage 6 between the two-rowed bonding tapes 4, 5, and water is sent into the water passage 6 to cool and pressurize the joint 3, to thereby specify a failure spot in the joint 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for inspecting a water-impervious sheet joint, and more particularly to a method for inspecting a water-impervious sheet joint that allows normal inspection of the joint even at high temperatures such as in summer.

  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 a joining of water-impervious sheets, a water passage is formed in the joint and a pressure spot in the water passage is detected in a state where the inside of the water passage is depressurized to detect a defective portion in the joint. 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 water 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 pressure fluctuation by pressurizing or depressurizing the inside of the water 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, in the pressurization inspection / decompression inspection with air as described above, the sheet tends to stretch at high temperatures in the summer, and the peel strength of the joint may decrease, making it difficult to maintain the pressure during the inspection. Although there was no defect and no water leakage occurred, the pressure sometimes fluctuated, and there was a problem that inspection accuracy and inspection efficiency deteriorated. In particular, when the material of the sheet is asphalt, the sheet is joined by fusion with a burner or hot air, and the sheet thickness is as thick as 3 to 5 mm. On the other hand, if the temperature exceeds 40 ° C., the peel strength at the joint portion is greatly reduced, so that pressure cannot be maintained.

  In addition, in the inspection work for water leakage by air, the inspection itself for confirming the presence or absence of a defect is simple, but it has been difficult to identify the defective part after it has been found that there is a defect.

  Accordingly, an object of the present invention is to provide a method for inspecting a water shielding sheet joint that allows easy identification of a defective portion and enables more accurate inspection even at high temperatures in summer.

  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 forming two rows of joints at intervals in the width direction of the joints at the overlap between sheets, a water passage is formed between the two rows of joints, and water is injected into the water passage. It is characterized by detecting a joint defect by capturing the change of water in the inside.

  In Claim 2, it is set as the test | inspection method of the water shielding sheet junction part of Claim 1 whose change of water is a pressure fluctuation in the said water flow path.

  In Claim 3, it is set as the test | inspection spike method of the water-impervious sheet | seat junction part of Claim 1 whose change of water is a leakage of the water from the said water flow path.

  In Claim 4, prior to capturing the change in the water in the water channel, the method includes a step of flowing water in the water channel to lower the temperature of the water shielding sheet. It is an inspection method for water sheet joints.

  According to the first aspect of the present invention, water is injected into the water passage formed at the joint and the defect of the joint is detected by detecting the change in the water. The joint is cooled by water injected into the water channel, and a more accurate inspection can be performed.

  In Claim 2, the pressure fluctuation of water is employ | adopted as a method of catching the change of the water in a water channel, and the presence or absence of a defect can be detected immediately regardless of where the defect exists.

  In claim 3, water leakage from the water channel is adopted as a method for capturing the water change in the water channel, and it is possible to immediately identify not only the presence or absence of a defect but also a defective part. Have.

  According to the fourth aspect of the invention, the inspection is performed after flowing water through the water passage and the temperature of the water shielding sheet at the joint portion is surely lowered, so that a more accurate inspection can be performed.

  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 water passage 6 having water tightness surrounded by the upper and lower water shielding sheets 2 and 3 and the two joining tapes 4 and 5 is formed. The water passage 6 is usually partitioned in units of a predetermined length, and inspection is performed for each section.

  In this state, water is injected into the water passage 6 and pressurized, and the subsequent pressure change in the water 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 3 and that air has entered the water passage 6 that has been depressurized.

  If there is no defective portion, the inspection of the section is finished, but if there is a defective portion, it is visually checked along the water passage 6 to find a portion where water leakage has occurred. If the water leaking part 8 as shown in FIG. 3 is found, it can be found that the part is a defective part and the place can be specified.

  If the defective part can be identified, it is repaired by a method such as adding and attaching the part. When the repair is completed, water is injected again into the section including the defective portion of the water passage 6 to confirm the presence or absence of the defective portion. If there is a defective portion, the location of the water leak is searched and the defective portion is specified, such a process is repeated, and the inspection is performed in all sections of the partitioned water passage 6 so that the joint portion 3 having no defective portion is formed. Obtainable.

  In the above example, the example in which the water shielding sheets 1 and 2 are bonded to each other by bonding with the adhesive tapes 4 and 5 is described, but is limited to the bonded portion 3 bonded with the adhesive tapes 4 and 5. Instead, the present invention can also be applied to the case where the water passage 6 is provided in the joint portion 3 by joining by heat fusion.

  In both of the adhesion of the water shielding sheets 1 and 2 with the adhesive tapes 4 and 5 and the fusion by heat fusion, the material constituting the water shielding sheets 1 and 2 is softened firstly at high temperatures in summer. And become easier to stretch. If it does so, even if water will be inject | poured into the said water flow path 6 and pressure will be applied, an expansion | swelling will generate | occur | produce in the water-impervious sheets 1 and 2, and a pressure may fall. In addition, the strength of the adhesive tapes 4 and 5 may be reduced and elongation may occur, which may reduce the pressure of water in the water passage 6.

  Then, it cannot be determined whether the water pressure is lowered due to the defect in the joint 3 or whether the water pressure is lowered due to the extension of the water shielding sheets 1, 2 and the adhesive tapes 4, 5. Accuracy will be lost.

  In this invention, water is inject | poured into the water flow path 6, and the water-impervious sheet 1 and the adhesive tapes 4 and 5 in the junction part 3 can be cooled by water by doing so. Therefore, the water shielding sheets 1 and 2 and the adhesive tapes 4 and 5 are soft and easily stretched due to high temperatures such as in summer. By suppressing the pressure drop due to elongation by cooling water by injecting water into the water passage 6, the high inspection could not be performed or the high pressure could not be applied. Can be performed with high accuracy.

  In the invention according to claim 4 of the present invention, when the joint 3 is inspected, first, water is continuously injected into the water passage 6 of the joint 3 and the water passage 6 is cooled until the temperature is lowered to some extent. It is said that after the water has continued to flow and the temperature has dropped sufficiently, the water pressure is applied to the water passage 6 and the actual inspection process is started to capture changes in water such as pressure drop and water leakage. .

  By doing so, it becomes possible to perform a more accurate and accurate inspection. Although it is a cooling process by flowing water into the water passage 6, water is poured using a pump 11 from the water inlet 10 at one end in the water passage 6 as shown in FIG. 4. An irregular sealing material 12 or the like is arranged at the water inlet 10, and the insertion tube 14 at the tip of the hose 13 connected to the pump 10 is inserted into the irregular sealing material 12 of the water inlet 10 to feed water. . Then, water is discharged from the discharge port 15 at the other end, the temperature of the water discharged from the discharge port 15 is measured, and water is kept flowing until the water temperature becomes 30 ° C. or lower. When the water temperature coming out of the discharge port 15 becomes 30 ° C. or lower, the flow of water is stopped. In a state where the discharge port 15 is sealed with the irregular sealing material 12 or the like, water is fed from the water inlet 10 so as to have a predetermined water pressure, and the inside of the water passage 6 is kept at a constant water pressure. A pressure gauge 16 is attached at an intermediate position of the hose 13.

  In that state, leave it for a while and check for changes in water pressure. If the water pressure has decreased, there will be a defect somewhere, so the location where the water is leaking can be confirmed visually, and the leak location can be identified by doing so.

  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, it is preferable to place the sealing material 7 outside the joining tape 4 because safety can be further increased.

  At this time, the sealing material 7 may be arranged on the outer side of the bonding tape 4 disposed at the end of the lower water-impervious sheet among the bonding tapes 4 and 5 forming the water passage 6, and as shown in FIG. In addition to the sealing material 7, a bonding tape 9 can be additionally stretched on the surface side of the bonding portion 3.

  What can be used as the water-impervious sheets 1 and 2 in the present invention includes, for example, vulcanized rubber made of ethylene / propylene / diene monomer, butyl rubber, or a blend thereof, thermoplastic resins such as vinyl chloride and vinyl acetate, Examples include plastic elastomers and rubberized asphalts.

  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 water passage 6 are determined by the arrangement and thickness of the joining tapes 4 and 5, and the thickness of the joining tapes 4 and 5 is 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.

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 top view which shows a mode that the inspection method of this invention is implemented.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water-impervious sheet 2 Water-impervious sheet 3 Joining part 4 Joining tape 5 Joining tape 6 Water passage 7 Sealing material 8 Abnormal part 9 Joining tape 10 Inlet 11 Pump 12 Indeterminate sealing material 13 Hose 14 Insertion pipe 15 Outlet 16 Pressure gauge G groundwork

Claims (4)

  In the method of inspecting leakage at the joint portion where the water shielding sheets are joined together, the joining portion of the water shielding sheets is overlapped with the joining margin of the water shielding sheets to be joined at an interval in the width direction of the joining portion. It is possible to form a water passage between two rows of joints by joining the rows, inject water into the water passage, and detect a defect in the joint by capturing the water change in the water passage. A method for inspecting a junction of a water shielding sheet as a feature.   The method for inspecting a water shielding sheet joint according to claim 1, wherein the change in water is a pressure fluctuation in the water passage.   The method for inspecting a water-impervious sheet joint according to claim 1, wherein the change in water is leakage of water from the water passage.   Prior to capturing the change in the water in the water channel, the step of flowing the water in the water channel and lowering the temperature of the water shielding sheet includes the step of reducing the temperature of the water shielding sheet. Inspection method.

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