JP2005185987A - Impervious structure and leakage sensing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impervious structure excellent in reliability of water leakage sensing of an impervious layer and a leakage sensing method excellent in reliability of leakage sensing which senses water leakage of the impervious structure. <P>SOLUTION: An impervious structure is provided with an impervious layer having insulation properties, an upper part electrode installed at the inside of the impervious layer and used for leakage sensing of the impervious layer, and a lower part electrode installed outside of the impervious layer and used for leakage sensing of the impervious layer. The lower part electrode possesses a first conductive layer installed over the whole area of the outer surface of the impervious layer and a second conductive layer connected to the first conductive layer and installed at only a part of the outer surface of the impervious layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  More particularly, the present invention relates to a water shielding structure capable of detecting water leakage provided in a waste disposal site or the like, and a water leakage detection for detecting water leakage of the water shielding structure. Regarding the method.

  In facilities such as a waste disposal site, a water-impervious structure including a water-impervious layer made of a water-impervious sheet or the like laid along a recess in the ground is usually provided. When constructing such a water-blocking structure, a leak inspection is performed by detecting the presence or absence of water leakage in the water-blocking structure at the stage when the installation of the water-blocking sheet is completed or when all construction is completed. Has been done. In addition, water leakage inspections are also performed during operations that are used as disposal sites.

Conventionally, as a water leakage detection method for performing such a water leakage inspection, for example, a current is supplied from a power source to the ground on which a water shielding sheet is laid to form a lower electrode, and an upper electrode is provided above the water shielding sheet. A method of detecting leakage of the water shielding sheet by measuring the current, potential or electric resistance between the lower electrode and the upper electrode is used.
Japanese Patent No. 3323398 JP 2003-21569 A Japanese Patent Application No. 2002-205750 Japanese Patent Application No. 2002-372274 JP-A-10-170468

  However, in the techniques described in Patent Literature 1 to Patent Literature 5, there are cases where the reliability of water leakage detection of the water shielding layer is insufficient.

  According to the water-blocking structure and the water leakage detection method of the present invention, it is possible to reliably detect water leakage in a specific area that requires attention when performing water leakage detection, such as an area where detection failure is likely to occur or an area where water leakage is likely to occur. Is done. Therefore, the water leakage detection reliability of the water shielding layer is excellent.

  This invention is made | formed in view of said subject, and it aims at providing the water shielding structure excellent in the reliability of the water leak detection of a water shielding layer.

  Moreover, it is the water leak detection method which detects the water leak of said water-blocking structure, It aims at providing the water leak detection method excellent in the reliability of water leak detection.

In order to solve the above problems, the water-impervious structure of the present invention is a water-impervious structure provided with a water-impervious portion provided along a recess in the ground,
The water shielding portion is provided with an insulating water shielding layer, an upper electrode provided on the inner side of the water shielding layer, used for detecting water leakage of the water shielding layer, and provided on the outer side of the water shielding layer. And a lower electrode used for water leakage detection of the water shielding layer,
The lower electrode includes a first conductive layer provided over the entire outer surface of the water shielding layer,
And a second conductive layer that is electrically connected to the first conductive layer and provided only on a part of the outer surface of the water shielding layer.

  The inventors of the present invention have conducted extensive research and have identified specific areas that require attention when performing leak detection (hereinafter, referred to as “caution areas”), such as areas where detection failures are likely to occur and areas where leakage is likely to occur. It was found that the reliability of leak detection of the water shielding layer can be effectively improved by ensuring that the leak of water is detected.

  In the water shielding structure of the present invention, the lower electrode includes a first conductive layer provided over the entire outer surface of the water shielding layer, and a second conductive layer provided only on a part of the outer surface of the water shielding layer. By providing the second conductive layer in the caution area, water leakage in the caution area can be reliably detected. Therefore, the water leakage detection reliability of the water shielding layer is excellent.

  Moreover, since the 2nd conductive layer and the 1st conductive layer are conduct | electrically_connected, the water-blocking structure of this invention detects the water leak of a caution area | region and the water leak of the whole outer surface of a water-blocking layer simultaneously. Therefore, for example, even if the leakage of the caution area can be reliably detected, the work of detecting the leakage of the caution area and the work of detecting the leakage of the entire outer surface of the impermeable layer must be performed separately. Compared to the case where it is not necessary, the work for detecting leakage of the water shielding layer is less.

  Further, in the water shielding structure of the present invention, since the second conductive layer is provided only on a part of the outer surface of the water shielding layer, for example, the second conductive layer is provided over the entire outer surface of the water shielding layer. In comparison, the construction labor is small, the amount of material used for the second conductive layer is small, and the cost is low.

  In addition, the attention area here is, as described above, an area where detection failure is likely to occur or an area where water leakage is likely to occur, and specific examples include the following areas.

  As a region where water leakage is likely to occur, for example, a joint portion formed by joining adjacent water shielding sheets in the case where the water shielding layer is formed by joining a plurality of water shielding sheets can be exemplified. . Such a joint is an area where water leakage is likely to occur due to poor joining during construction.

  In addition, examples of the region where detection failure is likely to occur include the slope portion of the recess. The sloped portion of the recess is a region where water does not stay, and therefore, when the lower conductive layer uses conductivity due to moisture, the conductivity of the lower electrode is insufficient and water leakage may not be detected.

  Therefore, in the above-described water-impervious structure, the water-impervious layer is formed by joining a plurality of water-impervious sheets, and the second conductive layer is a joint portion formed by adjoining adjacent water-impervious sheets. It may be provided at least on the outer surface.

  By setting it as such a water-impervious structure, the water leak by the joining defect at the time of construction in a junction part can be detected reliably. In the above-described water-impervious structure, the second conductive layer may be provided at least on the slope portion of the recess. By setting it as such a water-impervious structure, it is possible to prevent water leakage detection failure at the slope of the recess. Moreover, in said water-impervious structure, a said 2nd conductive layer can be made into a conductive nonwoven fabric.

  By making such a water-impervious structure, it is possible to reduce the impact on the water-impervious layer, and it is excellent in durability and weather resistance, can be easily made to a desired size, and is good only by laying. A conductive second conductive layer can be formed. Moreover, in said water-impervious structure, the said conductive nonwoven fabric may be a nonwoven fabric containing carbon.

  By using such a water-blocking structure, it is possible to provide a water-blocking structure having a second conductive layer that is inexpensive, excellent in durability and weather resistance, is easily available, and has good conductivity. . Further, in the above water-proof structure, the second conductive layer may be an aluminum sheet.

  By setting it as such a water-impervious structure, it can be easily made into a desired size, and the 2nd conductive layer which has favorable electroconductivity can be formed only by laying.

Further, in the above-described water-impervious structure, a third conductive layer is provided outside the lower electrode,
Between the lower electrode and the third conductive layer, there is provided a coating layer that has an insulating property and covers the third conductive layer, and the lower electrode and the third conductive layer are electrically connected. It is possible to provide a conductive portion that is electrically connected.

  In such a water shielding structure, the third conductive layer is provided outside the lower electrode, the insulating layer is provided between the lower electrode and the third conductive layer, and the third conductive layer is covered. And a conductive portion for electrically connecting the lower electrode and the third conductive layer, so that a current is supplied from the power source to the third conductive layer, and the conductive portion is Current can flow through the lower electrode. Therefore, it is provided with a high-quality third conductive layer that is protected from rainfall during construction by being covered with an insulating coating layer, and further, a current, potential or electric current between the lower electrode and the upper electrode is provided. By the method of measuring resistance, it is possible to realize a water shielding structure capable of easily detecting water leakage in the water shielding layer.

In the above-described water shielding structure, a plurality of detection electrodes that are electrically connected to the upper electrode,
A power source for supplying current to the upper electrode and the lower electrode;
Current measuring means for measuring current flowing through the plurality of sensing electrodes,
Supplying a current to the lower electrode to measure a current flowing through the plurality of sensing electrodes;
Supplying current to the upper electrode, and measuring the current flowing through the plurality of sensing electrodes;
The leakage shape of the water shielding layer is detected by comparing the distribution shape of the current distribution obtained when current is supplied to the lower electrode and the distribution shape of the current distribution obtained when current is supplied to the upper electrode. can do.

  According to such a water-blocking structure, even if the electrical resistance varies depending on the thickness of the protective layer provided on the water-blocking layer, the installation state of the electrodes, etc. Even if there is a drainage groove that communicates with the outside, even if it leaks from other than the leak location of the impermeable layer, the leak of the impermeable layer can be detected with high accuracy, and the leak location Can be specified.

In the water shielding structure, a plurality of upper inspection electrodes that are electrically connected to the upper electrode,
A power supply for supplying current to the lower electrode;
Current measuring means for measuring a current flowing through the plurality of upper inspection electrodes,
A computer system for summing up the currents flowing through the plurality of upper inspection electrodes measured by the current measuring means and detecting leakage of the water shielding layer may be included.

  According to such a water shielding structure, it is possible to easily detect water leakage by summing the currents flowing through the upper inspection electrodes.

In the above water-blocking structure, the lower electrode includes a plurality of point electrodes,
An upper inspection electrode electrically connected to the upper electrode;
A power source for passing a current between the point electrode and the upper inspection electrode;
Current measuring means for measuring a leakage current caused by water leakage of the water shielding layer;
Electrode switching means;
Control means for forming different leakage current paths between the upper inspection electrode and the point electrodes;
It is good also as what detects a water leak location by the electric current distribution over the whole area of the said water shielding layer of the said leak current which flows into the said leak current path | route.

  According to such a water-impervious structure, water leakage can be detected quickly, and the water leakage position can be accurately determined without being affected by the specific resistance distribution of the ground or waste.

Furthermore, in the above-described waterproof structure, a reference electrode is provided,
The following formula (1) of the leakage current and the current flowing between the upper inspection electrode and the reference electrode

により与えられる比（Ｋ）を用いて前記漏水箇所を検出するものとしてもよい（式（１）中、Ｉは、漏洩電流であり、Ｉｒは、前記上部電極と前記基準電極の間に流れる電流を示す。）。

The leak location may be detected using the ratio (K) given by (wherein I is a leakage current, and Ir is a current flowing between the upper electrode and the reference electrode) Is shown.)

  According to such a water shielding structure, the water leakage position can be determined with higher accuracy.

  Moreover, in order to solve said subject, the water leak detection method of this invention is a water leak detection method which detects the water leak of the water-impervious structure in any one of the above, and the upper electrode and the lower electrode It is characterized by detecting water leakage of the water shielding layer by conducting between them.

  According to such a water leak detection method, it is possible to reliably detect water leak in the caution area, and to detect water leak in the water shielding layer with high accuracy.

(First embodiment)
Hereinafter, the water shielding structure and the water leakage detection method of the present invention will be described in detail by way of examples. FIG. 1 is a schematic cross-sectional view showing an example of a waste disposal site to which the water-impervious structure of the present invention is applied. In addition, in FIG. 1, in order to make drawing easy to see, the junction part and conduction | electrical_connection part of the water-impervious sheet are shown on behalf of only two.

  2 and 4 are enlarged plan views showing a part of the water shielding structure shown in FIG. In FIG. 2, only the resin sheet constituting the coating layer and the conductive material constituting the conduction part are shown for explaining the planar arrangement of the conduction part, and in FIG. 4, the joint part of the water shielding sheet is shown. In order to explain the planar arrangement, only the second conductive layer provided on the outer surface of the joint between the water shielding sheet and the water shielding sheet is shown.

  3 and 5 are cross-sectional views showing an enlarged part of the water-impervious structure shown in FIG.

  The waste disposal site shown in FIG. 1 is composed of a recess of the ground 1 and a water-impervious portion provided along the recess in the entire area within the recess. In this waste disposal site, waste is dumped inside the impermeable section. Moreover, the sewage generated by rainwater or the like is prevented from leaching out of the water shielding portion by the water shielding portion.

  The concave portion of the ground 1 can be artificially formed by excavating downward from the ground surface, and when using a valley or a valley such as a mountainous area, the topography thereof can also be used.

  As shown in FIG. 1, the water-impervious portion includes an earth-impervious layer 6 (corresponding to “third conductive layer” in claims), a cover layer 3, a lower electrode 2, and an insulating barrier. The water layer 7, the upper nonwoven fabric 13 (corresponding to the “upper electrode” in the claims), and the sand layer or the lining 4 are sequentially provided from the ground 1 side.

  The soil impervious layer 6 has poor water permeability formed by a mixed soil obtained by mixing a locally generated soil generated by excavation of the ground 1 for providing a recess, etc. with bentonite (a very fine clay particle). Is. In the water-impervious structure shown in FIG. 1, the soil water-impervious layer 6 has poor water permeability, so that the water-impervious layer 7 and the soil water-impervious layer 6 have a double water-impervious structure. Yes. The soil impermeable layer 6 has conductivity and is electrically connected to the ground 1. Furthermore, the soil impermeable layer 6 also functions as a protective layer that protects the impermeable layer 7 by absorbing impacts from above.

  As the covering layer 3, any soil-impervious layer 6 can be coated as long as it has a water-impervious property capable of preventing the soil impervious layer 6 from becoming mud due to rain or the like, thereby preventing deterioration in workability and quality. Even a thickness or material can be used. The covering layer 3 is preferably a sheet-like layer that can cover the soil impermeable layer 6 by laying on the surface of the soil impervious layer 6, and is formed of, for example, the same material as the impermeable layer 7 described later. Is done.

  In this embodiment, the coating layer 3 is formed of a long resin sheet having a certain width. As shown in FIG. 2, a seam 3 c between the resin sheet and the resin sheet is formed in the covering layer 3 in a band shape. The seam 3c exists at a predetermined interval determined by the width of the resin sheet to be the coating layer 3. Further, the seam 3c is formed by laying a resin sheet so as to correspond to the surface shape of the soil impermeable layer 6, and as shown in FIGS. Adjacent resin sheets 3a and 3b are overlapped with each other.

  In the present embodiment, as shown in FIGS. 1 and 3, the soil impermeable layer 6 is electrically connected to the lower electrode 2 by a plurality of conductive portions 15.

  The conductive portion 15 may be formed of any material as long as it has conductivity. For example, metal such as iron, copper, lead, aluminum, palladium, polyaniline, polyacetylene, polypyrrole, polythiophene, polyacene, polypara Examples thereof include conductive polymers such as phenylene, carbon black, and graphite.

  The conducting portion 15 may have any shape and size as long as the lower electrode 2 and the soil impermeable layer 6 can be conducted. However, the conducting portion 15 is preferably made of a sheet-like conductive material 14.

  In this embodiment, the conduction | electrical_connection part 15 consists of a sheet-like electroconductive material 14, and as shown in FIG. 3, the upper layer side part provided so that the electroconductive material 14 might contact the lower nonwoven fabric 12 and the coating layer 3 was shown. 15a, a lower layer side portion 15b provided so that the conductive material 14 is in contact with the coating layer 3 and the soil impermeable layer 6, and an upper layer side portion 15a and a lower layer side portion 15b. The intermediate portion 15c is in contact with the coating layer 3 on both sides. The upper layer side portion 15a, the lower layer side portion 15b, and the intermediate portion 15c are formed by inserting the conductive material 14 into a portion where the adjacent resin sheets 3a and 3b are overlapped.

  Moreover, in this embodiment, as shown in FIG. 2, the conduction | electrical_connection part 15 is provided with two or more, and arrange | positions at equal intervals by utilizing the joint 3c of the resin sheet and resin sheet which were formed at fixed intervals. Has been.

  The lower electrode 2 is provided outside the water shielding layer 7 and is used for detecting water leakage in the water shielding layer 7. The lower electrode 2 is electrically connected to the lower nonwoven fabric 12 (corresponding to the “first conductive layer” in the claims) provided on the entire outer surface of the water shielding layer 7 and the lower nonwoven fabric 12. Conductive nonwoven fabrics 5a and 5b (corresponding to the “second conductive layer” in the claims) provided in advance on a part of the outer surface of the water-impervious layer 7 by being laid in advance at predetermined positions. doing.

  The upper nonwoven fabric 13 is provided on the inner side of the water-impervious layer 7 and is used for water leakage detection of the water-impervious layer 7.

  Any material can be used as the lower nonwoven fabric 12 and the upper nonwoven fabric 13 as long as they can be laid and can obtain predetermined conductivity by being in a wet state.

  As the conductive non-woven fabrics 5a and 5b, any material can be used as long as the predetermined conductivity can be obtained without being in a wet state. For example, it is inexpensive and has excellent durability and weather resistance. Examples of preferable conductive nonwoven fabrics 5a and 5b that are easily available and have good conductivity include carbon-containing nonwoven fabrics. As the non-woven fabric containing carbon, for example, a long one having a certain width such as Crecos (trade name) manufactured by Nippon Poly Products Co., Ltd. is preferable because it is excellent in workability.

  The water-impervious layer 7 may be any thickness or material as long as necessary water-impervious, durable, and insulating properties can be obtained, but is preferably formed of a synthetic rubber or plastic water-impervious sheet. . Specifically, linear low density polyethylene (LLDPE), medium density polyethylene (MDPE) manufactured with a metallocene catalyst, linear low density polyethylene (LLDPE), medium density polyethylene manufactured with a Ziegler-Natta catalyst. A water shielding sheet formed from an olefin resin such as (MDPE) is preferably used. Moreover, when using a water shielding sheet, in order to improve the water shielding performance, a plurality of sheets may be used as necessary.

  In the present embodiment, the water shielding layer 7 is formed by laying a plurality of water shielding sheets on the lower nonwoven fabric 12. As shown in FIG. 4, the water-impervious sheet is a long one having a certain width, and as shown in FIG. 5, adjacent water-impervious sheets 7a and 7b are overlapped with each other in order to reliably shield the water. Combined and joined. And as shown in FIG. 4, the junction part 7c formed by joining adjacent water-impervious sheets is formed in a strip shape with a constant interval determined by the width of the water-impervious sheet. As a method for joining the water-impervious sheets 7a and 7b, it is only necessary that the adjacent water-impervious sheets 7a and 7b can be reliably joined, and it is determined by the material of the water-impervious sheets 7a and 7b, and is not particularly limited. The method of using, the method of using an adhesive agent, etc. can be mentioned.

  A conductive nonwoven fabric 5a laid in advance before laying the water-impervious sheet is provided along the joint 7c on the outer surface of the joint 7c. The width of the conductive nonwoven fabric 5a is misaligned between the position where the conductive nonwoven fabric 5a is laid and the position where the water shielding sheet is laid on the conductive nonwoven fabric 5a in order to improve the reliability of water leakage detection at the joint 7c. As shown in FIGS. 4 and 5, it is desirable to make the width wider than the joint portion 7 c in order to secure an allowable range for improving the workability. However, if the width of the conductive nonwoven fabric 5a is too wide, the workability is deteriorated and the workability is deteriorated, and the inconvenience such as an increase in the amount of the conductive nonwoven fabric 5a used occurs. For this reason, it is desirable that the width of the conductive nonwoven fabric 5a be in a range from the width of the joint portion 7c to a width that is 200 mm wider than the width of the joint portion 7c. Furthermore, as shown in FIG. 1, the conductive nonwoven fabric 5b is provided over the entire slope of the recess of the ground 1.

  The sand layer or the cover soil 4 is adjacent to the waste, and is installed to protect the water shielding layer 7 from an impact or the like when the waste is dumped. Further, the sand layer or the cover soil 4 is formed by installing sand or soil until the height necessary for protecting the water shielding layer 7 is reached.

  Next, a water leak detection method for detecting the water leak of the water shielding structure shown in FIGS. 1 to 5 will be described.

  In order to detect leakage of the water-impervious structure, first, as shown in FIG. 1, a power source 9 and a current measuring means 10 are provided.

  The power source 9 supplies current to the upper inspection electrode 81 and the lower inspection electrode 82. The upper inspection electrode 81 is embedded in the sand layer or the covering soil 4 and disposed on the upper nonwoven fabric 13. The lower inspection electrode 82 is disposed on the ground 1 outside the water shielding portion 2.

  The upper inspection electrode 81 and the lower inspection electrode 82 used here may be any material as long as they are conductive, for example, metals such as iron, copper, lead, aluminum, and palladium, polyaniline, polyacetylene, and polypyrrole. , Conductive polymers such as polythiophene, polyacene, and polyparaphenylene, carbon black, and graphite. Further, the upper inspection electrode 81 and the lower inspection electrode 82 may have any shape such as a flat plate or a columnar shape, and a protrusion or the like for improving retention is provided on the installation surface side as necessary. It may be.

  The current measuring means 10 measures the current that flows between the upper inspection electrode 81 and the lower inspection electrode 82, and flows between the upper inspection electrode 81 and the lower inspection electrode 82. Any device capable of measuring current can be used.

  Next, a current is supplied to the upper inspection electrode 81 from the power source 9, thereby causing a current to flow through the upper nonwoven fabric 13. Further, by supplying current from the power source 9 to the lower inspection electrode 82, the lower nonwoven fabric 12 and the conductive nonwoven fabric 5a from the ground 1 outside the water shielding portion through the soil impermeable layer 6 and the conduction portion 15; Current is passed through 5b. Then, by measuring the current flowing between the upper inspection electrode 81 and the lower inspection electrode 82 by the current measuring means 10, it is possible to detect the presence or absence of water leakage in the water shielding layer 7.

  At this time, in this embodiment, since the conductive nonwoven fabrics 5a and 5b are provided on the entire outer surface of the joint 7c and the entire slope of the recess, of the outer surface of the water shielding sheet, the outer surface of the joint 7c and Electricity can surely flow through the entire slope of the recess.

  According to such a water-blocking structure and a water leakage detection method, water leakage is reliably detected on the outer surface of the joint 7c and the entire slope of the recess, which is a region where detection failure is likely to occur and a region where water leakage is likely to occur. The Therefore, the water leakage detection of the water shielding layer 7 is excellent in reliability. And compared with the case where the electroconductive nonwoven fabric 5a, 5b is provided in the whole outer surface of the water-impervious layer 7, the usage-amount of the electroconductive nonwoven fabric 5a, 5b may be small, and construction is also easy.

  Moreover, in the water-impervious structure of the present invention, since the conductive nonwoven fabrics 5a and 5b are provided only on a part of the outer surface of the water-impervious layer 7, for example, the lower electrode is integrated with the water-impervious sheet having insulating properties. Thus, there is no problem that it is difficult to join adjacent sheets as in the case where the lower electrode and the water shielding layer are formed by joining a plurality of sheets.

  More specifically, when the lower electrode and the insulating water shielding sheet are integrated, when the adjacent sheets are superposed, the conductive material constituting the lower electrode is water shielding. It will be placed on the insulating material that makes up the layer. For this reason, in the above case, it is necessary not only to reliably join the sheets so as to prevent water leakage but also to take measures to avoid conduction between the upper surface and the lower surface of the sheet.

  On the other hand, in the water-impervious structure of the present invention, since the conductive nonwoven fabrics 5a and 5b are provided only on part of the outer surface of the water-impervious layer 7, the water-impervious layer 7 is joined to a plurality of water-impervious sheets. Even if it is what was done, a lower electrode does not affect the joining operation | work of a water-impervious sheet at all, and construction is easy.

  The water shielding structure and the water leakage detection method of the present invention are not limited to the above example. For example, in the above water shielding structure, the second conductive layer may be an aluminum sheet.

  For example, instead of the lower nonwoven fabric 12 and the upper nonwoven fabric 13, a layer made of a conductive material may be provided.

  Further, when sufficient water shielding performance can be obtained with only the water shielding layer 7, the soil water shielding layer 6 does not need to have poor water permeability. Therefore, the water shielding layer 7 is used instead of the soil water shielding layer 6. You may provide the protective soil layer which protects. Furthermore, if the impermeable layer 7 can be sufficiently protected in the recess of the ground 1, the soil impermeable layer 6 or a protective soil layer provided in place of the soil impermeable layer 6 may not be formed.

  Furthermore, as described above, it is desirable that a plurality of the conductive portions 15 are provided, but at least one conductive portion 15 may be provided and is not particularly limited.

  Moreover, the conduction | electrical_connection part 15 should just be what can connect the lower nonwoven fabric 12 and the soil water-impervious layer 6, for example, when laying the lower nonwoven fabric 12, the penetration layer 3 is penetrated to the coating layer 3. For example, the lower nonwoven fabric 12 and the soil water-impervious layer 6 may be in direct contact with each other.

  Further, in order to improve the water shielding performance and to fix the position of the resin sheet and the conducting portion 15, between the adjacent resin sheets 3a and 3b, or between the adjacent resin sheets 3a and 3b and the conductive material 14. May be adhered by an adhesive or the like.

  Further, the upper inspection electrode 81 and the lower inspection electrode 82 are installed at any position as long as it can detect that the current supplied from the power source 9 flows through the water leakage portion of the water shielding layer 7. May be.

  For example, the upper inspection electrode 81 is preferably installed so as to be in direct contact with the upper nonwoven fabric 13 as shown in the above-described example in order to reliably supply current to the upper nonwoven fabric 13. You may arrange | position on the sand layer or the covering soil 4 in the stage where construction was completed. In this case, an electric current is supplied to the upper nonwoven fabric 13 through the sand layer or the covering soil 4.

  The lower inspection electrode 82 may be embedded in the soil impermeable layer 6 or may be embedded in the ground 1.

  Moreover, the water leak detection method of this invention can be used conveniently also in the stage before providing a sand layer or the covering soil 4, the time of operation used as a disposal site, etc.

  Further, the upper inspection electrode 81 may be movable when water leakage is detected. In this case, water leakage detection is possible even without the upper nonwoven fabric 13, and therefore the water leakage detection method of the present invention can be suitably used even when the water shielding layer 7 is provided.

  Further, in the above-described example, the conductive nonwoven fabrics 5a and 5b are provided on the entire outer surface of the joint portion 7c and the slope of the recess, but the region where the conductive nonwoven fabrics 5a and 5b are provided is one of the outer surfaces of the water shielding layer 7. It should just be provided only in the part, and it is determined by the use of the water shielding structure, etc., and is not limited to the above example. For example, the conductive non-woven fabrics 5a and 5b may be provided only at the joints on the slope of the recess, or may not be provided on the slope of the recess.

(Second Embodiment)
Hereinafter, the water shielding structure and the water leakage detection method of the second embodiment of the present invention will be described in detail. FIG. 6 is a schematic cross-sectional view showing another example of a waste disposal site to which the impermeable structure of the present invention is applied. Components similar to those in FIG. 1 shown in FIG. 6 are denoted by the same reference numerals as those in FIG.

  In the second embodiment, unlike the above-described first embodiment, the soil impermeable layer 6 shown in FIG. 6 corresponds to the “first conductive layer” in the claims, and the sand layer or the lining 4 is claimed. It corresponds to the “upper electrode” in the range. Therefore, the lower nonwoven fabric 12, the coating layer 3, and the upper nonwoven fabric 13 in FIG. 1 are not provided.

  Further, in the embodiment shown in FIG. 6, a drainage groove 27 is provided for draining the leachate inside the water shielding layer 7 from the inside of the water shielding layer 7 toward the outside of the water shielding layer 7. The drainage groove 27 is manufactured from an insulating material such as a polymer resin such as concrete or vinyl chloride. However, if the drainage groove 27 is a seam with a water-blocking structure or a concrete member, moisture is contained therein. Alternatively, it is in an electrically conductive state through its interior and drainage. In FIG. 6, the drainage grooves 27 can have a size and a number that allow an appropriate amount of leachate to be discharged so that leachate such as rainwater is not stored inside the impermeable layer 7. In the present invention, the current leaks from the drainage groove 27 as well as the edge of the water-impervious layer 7 and the road attachment.

  The water-blocking structure shown in FIG. 6 includes a plurality of detection electrodes 29 disposed on the upper portion 28 of the sand layer or the covering soil 4, a lower inspection electrode 20 disposed on the ground 1 outside the water-blocking layer 7, and a sand layer. Or while supplying an electric current to the soil water-impervious layer 6 and the conductive nonwoven fabrics 5a and 5b via the upper inspection electrode 21 and the lower inspection electrode 20 disposed on the bottom surface portion 8 in the recess in the cover soil 4, A constant current power source 22 for supplying current to the sand layer or the lining 4 via the upper inspection electrode 21 and current measuring means 23 for measuring the current flowing through the detection electrode 29 are included. Furthermore, the water-blocking structure shown in FIG. 6 acquires the current value flowing through each sensing electrode 29 measured by the current measuring means 23, calculates the current distribution using the acquired current value, and performs the lower inspection. Computer system for determining the presence or absence of water leakage by comparing the distribution shape of the current distribution obtained when a current is supplied to the electrode 20 and the current distribution obtained when a current is supplied to the upper inspection electrode 21 24 and a control device 25 including a switch for forming a specific circuit using the amount of current to be supplied and each detection electrode 29.

  The detection electrode 29 may be arranged at any position as long as it can detect that the current supplied from the lower inspection electrode 20 flows through the water leakage portion of the water shielding layer 7. Any shape and size may be used. In addition, when the detection electrode 29 is disposed on the upper part 28 of the sand layer or the covering soil 4 and waste is dumped on the upper part 28, it is preferable to use one made of a corrosion-resistant material. As long as it is easy to replace even if it is corroded, it is not limited to a corrosion-resistant material, and any material that can be used as an electrode may be used. Furthermore, any number of detection electrodes 29 may be provided, and a structure in which a protrusion or the like is provided on the side facing the sand layer or the covering soil 4 in order to improve the retention property may be used.

  Current is separately supplied to the lower inspection electrode 20 and the upper inspection electrode 21 shown in FIG. Therefore, when a current is supplied from the constant current power source 22 to the lower inspection electrode 20, no current is supplied to the upper inspection electrode 21, and a current is supplied to the upper inspection electrode 21. In such a case, no current is supplied to the lower inspection electrode 20.

  For example, when a current is supplied from the constant current power source 22 to the lower inspection electrode 20, the current passes from the lower inspection electrode 20 through the soil impermeable layer 6 and the conductive nonwoven fabrics 5 a and 5 b to the drainage groove. 27, the road, etc., and flows to the detection electrode 29 through the sand layer or the cover soil 4 inside the impermeable layer 7. Furthermore, if there is a water leak location in the water shielding layer 7, the current flows to the detection electrode 29 via the water leak location.

  When a current is supplied from the constant current power source 22 to the upper inspection electrode 21, the current flows from the upper inspection electrode 21 to the detection electrode 29 through the sand layer or the covering soil 4. In this case, the current may flow to the outside of the impermeable layer 7 through the edge of the impermeable layer 7, the road attachment portion, and the drainage groove 27. And when there is no leaking point, it flows again to the detection electrode 29 through a drainage groove (not shown) other than the drainage groove 27, the road, the sand layer or the cover soil 4, and when there is a leaking point, The current that has flowed out of the leaking point returns through the leaking point.

  At this time, in this embodiment, since the conductive nonwoven fabrics 5a and 5b are provided on the entire outer surface of the joint 7c and the entire slope of the recess, of the outer surface of the water shielding sheet, the outer surface of the joint 7c and Electricity can surely flow through the entire slope of the recess.

  Generally, as compared with the sand layer or the covering soil 4 between the upper inspection electrode 21 and the detection electrode 29, the electrical resistance between the upper inspection electrode 21 and the detection electrode 29 passing through the drainage groove 27 or the water leakage portion. Is big. For this reason, compared with the electric current which flows into the detection electrode 29 through the sand layer or the covering soil 4 from the electrode 21 for an upper test | inspection, the electric current which returns through a leak location becomes a trace amount. Even if this very small amount of current is shown in the current distribution, it hardly affects the distribution shape.

  The current flowing through each sensing electrode 29 is measured by the current measuring means 23, and the measured value is given to the computer system 24. In the computer system 24, current distributions are obtained based on the measured values of the current flowing through the detection electrodes 29 by the current measuring means 23, and their distribution shapes are compared. By doing so, water leakage can be detected with high accuracy even when the specific resistance distribution of the sand layer or the covering soil 4 varies.

  In the second embodiment, in order to measure the current flowing through the predetermined detection electrode 29, a control device 25 that allows a predetermined circuit to be formed can be provided. Then, by measuring the current flowing through the individual detection electrodes 29 and the voltage therebetween using the control device 25, calculating the electric resistance between them, and correcting the current value, it is possible to provide higher measurement accuracy. . In addition, the control device 25 can be configured to include a relay circuit, and the current flowing through each detection electrode 29 can be measured by switching the switch every predetermined time. In the present invention, the control device 25 can also be configured to include the constant current power source 22 and the current measuring means 23. In this case, the amount of current supplied from the constant current power source 12 can be controlled.

  In the second embodiment, a current is supplied from the constant current power source 22 as long as the electrical resistance of the conductive portion other than the water leakage location such as the drainage groove 27 is not equal to or smaller than that of the sand layer or the covering soil 4 or the ground 1. Since a difference occurs in the distribution shape of the current distribution obtained in this case, it is possible to detect the presence of a water leak location. Furthermore, in the difference in the distribution shape of the current distribution, the location of the water leak can be specified by the position showing the peak. Moreover, when specifying a water leak location, a predetermined threshold value is provided, and when there is a portion exceeding the threshold value, it is handled as a water leak location, and the peak can be specified as a water leak location. Furthermore, those below the threshold can be handled as measurement errors. The threshold value can be set to an appropriate value depending on the detection accuracy of the water leak location.

  As described above, according to the water shielding structure and the water leakage detection method of the second embodiment, after the water shielding layer 7 and the sand layer or the cover soil 4 are installed, the plurality of detection electrodes 29, the upper inspection electrode 21, and the lower inspection electrode are used. Even if the electrical resistance is different due to the difference in the thickness of the sand layer or the covering soil 4 or the installation state of the electrode, only by disposing the electrode 20, it is a case where leakage occurs from other than the water leakage location of the water shielding layer 7. In addition, it is possible to detect the presence / absence of a water leak location of the water shielding layer 7 with high accuracy and to identify the water leak location.

  Moreover, since the structure of the water-impervious structure of the second embodiment is simple, the construction period is short and the construction management is easy.

  Furthermore, also in the water-impervious structure and the water leakage detection method of the second embodiment, as in the first embodiment, the outer surface and the recess of the joint portion 7c, which are regions where detection failures are likely to occur and regions where water leakage is likely to occur. Water leakage across the slope is reliably detected. Therefore, the water leakage detection of the water shielding layer 7 is excellent in reliability. And compared with the case where the electroconductive nonwoven fabric 5a, 5b is provided in the whole outer surface of the water-impervious layer 7, the usage-amount of the electroconductive nonwoven fabric 5a, 5b may be small, and construction is also easy.

(Third embodiment)
Hereinafter, the water shielding structure and the water leakage detection method according to the third embodiment of the present invention will be described in detail. FIG. 7 is a schematic cross-sectional view showing another example of a waste disposal site to which the impermeable structure of the present invention is applied. Components similar to those in FIG. 1 shown in FIG. 7 are denoted by the same reference numerals as those in FIG.

  FIG. 8 is an enlarged plan view showing a part of the water shielding structure shown in FIG. In FIG. 8, only the water shielding layer, the sand layer or the lining, the upper inspection electrode, and the lower inspection electrode are shown in order to explain the planar arrangement of the upper inspection electrode.

  Also in the third embodiment, unlike the above-described first embodiment, the soil impermeable layer 6 shown in FIG. 7 corresponds to the “first conductive layer” in the claims, and the sand layer or the lining 4 is patented. This corresponds to the “upper electrode” in the claims. Therefore, the lower nonwoven fabric 12, the coating layer 3, and the upper nonwoven fabric 13 in FIG. 1 are not provided.

  In the embodiment shown in FIG. 7, a lower inspection electrode 38 disposed on the ground 1 outside the water shielding layer 7, and a plurality of upper inspection electrodes disposed on the bottom surface portion in the recess on the sand layer or the cover soil 4. A power source 39 for supplying current to the soil impermeable layer 6 and the conductive nonwoven fabrics 5a and 5b via the electrode 37, the lower inspection electrode 38, and a current measuring means 30 for measuring the current flowing through the upper inspection electrode 37. Including. The upper inspection electrode 37 may be installed at any position as long as it can detect that the current supplied from the lower inspection electrode 38 flows through the water leakage portion of the water shielding layer 7. Any shape and size may be used, and any number may be provided.

  In the embodiment shown in FIG. 7, one of the upper inspection electrodes 37 is a movable detection electrode 37 a, so that it is possible to specify a water leak location with high accuracy.

  As shown in FIG. 7, the upper inspection electrode 37 is connected to the current measuring means 30 for measuring the current flowing through each upper inspection electrode 37, and the lower inspection electrode 38 is for supplying a current. Each is connected to a power source 39. In FIG. 7, a current can be simultaneously supplied from the power source 9 to each upper inspection electrode 37, and the current flowing through each upper inspection electrode 37 can be measured by the current measuring means 30.

  In the present invention, one current measuring means 30 is used, the upper inspection electrodes 37 arranged at predetermined positions are switched using switches, and the total current flowing through each upper inspection electrode 37 is summed up. You may be able to measure. Further, the currents obtained by the plurality of current measuring means 30 corresponding to the respective upper inspection electrodes 37 are summed, and the currents and voltages flowing through the upper inspection electrodes 37 and the lower inspection electrodes 38 are monitored. A monitoring device equipped with a computer system may be provided.

  FIG. 8 is a plan view showing the arrangement of the upper inspection electrodes 37. As shown in FIG. 8, upper inspection electrodes 37 are arranged at four corners of a rectangular bottom surface portion 31 on which a sand layer or covering soil 4 is installed. Furthermore, the movable detection electrode 37a is arranged at an arbitrary position.

  In the embodiment shown in FIG. 7, when the current measuring means 30 detects the current flowing through the upper inspection electrode 37, it can be seen that there is a water leak location in the water shielding layer 7. A water leak location is specified using the movable detection electrode 37a. Specifically, as indicated by reference numeral A in FIG. 8, when the movable detection electrode 37a is moved, the current changes. Since the location where the current is the largest is the water leakage location, the water leakage location can be specified by moving the movable detection electrode 37a. Further, the difference between the measured current phase and the measured voltage phase differs depending on whether the water shielding layer 7 is damaged or not. In the present invention, the phase shift described above may be used when determining whether or not the water shielding layer 7 is damaged.

  When water leakage is detected using an alternating current, a current flows even if the water shielding layer 7 is not damaged. Therefore, it is necessary to measure in advance the current flowing through the water shielding layer 7.

  Further, in the embodiment shown in FIG. 7, the current flowing through each upper inspection electrode 37 may be measured after the sand layer or covering soil 4 is installed, and the total of the measured currents may be obtained, but the sand layer or covering soil 4 is installed. Doing so may cause damage to the water shielding layer 7. For this reason, each upper inspection electrode 37 is arranged on the water shielding layer 7 before the sand layer or the covering soil 4 is installed, the current flowing through each upper inspection electrode 37 is measured, and the total of the measured currents is obtained. It is preferable.

  As described above, in the embodiment shown in FIG. 7, water leakage can be easily detected by summing the currents flowing through the upper inspection electrode 37. Further, by using the movable detection electrode 37a, it is possible to quickly and easily specify the location of water leakage with high accuracy.

  Furthermore, in this embodiment, since the conductive nonwoven fabrics 5a and 5b are provided on the entire outer surface of the joint portion 7c and the slope of the recess among the outer surfaces of the water-impervious sheet, the outer surface and the concave portion of the joint portion 7c are provided. The electricity can flow reliably over the entire slope.

  Therefore, also in the water-impervious structure and the water leakage detection method of the third embodiment, as in the first embodiment, the outer surface and the recess of the joint portion 7c, which are regions where detection failures are likely to occur and regions where water leakage is likely to occur. Water leakage across the slope is reliably detected. Therefore, it becomes excellent in the reliability of the water leak detection of the water shielding layer 7. And compared with the case where the electroconductive nonwoven fabric 5a, 5b is provided in the whole outer surface of the water-impervious layer 7, the usage-amount of the electroconductive nonwoven fabric 5a, 5b may be small, and construction is also easy.

(Fourth embodiment)
Hereinafter, the water shielding structure and the water leakage detection method according to the fourth embodiment of the present invention will be described in detail. FIG. 9 is a schematic cross-sectional view showing another example of a waste disposal site to which the impermeable structure of the present invention is applied. Components similar to those in FIG. 1 shown in FIG. 9 are denoted by the same reference numerals as those in FIG.

  FIG. 10 is an enlarged plan view showing a part of the water shielding structure shown in FIG. In addition, in FIG. 10, while explaining the planar arrangement | positioning of the point electrode which comprises the water-impervious structure shown in FIG. 9, an upper test electrode, a power supply, an electrometer, an ammeter, an electrode switching means, and a control means This is for explaining the connection, and in order to make the drawing easy to see, components not used in the above description are omitted.

  Furthermore, also in the fourth embodiment, unlike the above-described first embodiment, the soil impermeable layer 6 shown in FIG. 9 corresponds to the “first conductive layer” in the claims, and is a sand layer or lining 4. Corresponds to the “upper electrode” in the claims. Therefore, the lower nonwoven fabric 12, the coating layer 3, and the upper nonwoven fabric 13 in FIG. 1 are not provided.

  As shown in FIG. 9, the water-impervious structure of the fourth embodiment includes a plurality of point electrodes 47 arranged on the ground 1 along the water-impervious portion composed of the water-impervious layer 7 and the soil impermeable layer 6. ing. The point electrode 47 is not particularly limited as long as it has a size and a shape that are sufficiently small with respect to the area of the water shielding portion and the interval at which the point electrodes 47 are arranged and can detect the leak position with sufficient accuracy. It may be. Further, the point electrode 47 can be formed from various materials such as iron, copper, lead, and stainless steel, and is suitable for the ground side in order to improve the retaining property to the ground 1 and improve the workability of the water shielding work. Protruding protrusions may be provided.

  In the water-impervious structure of the fourth embodiment shown in FIG. 9, the sand layer or the cover soil 4 covers the entire surface of the water-impervious layer 7 along the water-impervious layer 7 in order to protect the upper surface of the water-impervious layer 7. It is provided to cover. On the sand layer or the cover soil 4, the waste 33 is dumped, and an upper inspection electrode 48 is provided adjacent to the waste 33 and conducting to the sand layer or the cover soil 4. The upper inspection electrode 48 may be anything as long as a current caused by water leakage can flow through the sand layer or the lining 4, and may be arranged at any position. For example, it may be disposed on the water shielding layer 7, the sand layer or the lining 4, or may be embedded in the sand layer or the lining 4.

  As shown in FIG. 9, a power source 49 is connected between the point electrode 47 and the upper inspection electrode 48, and an electrometer 40 is provided to measure the potential at both ends of the power source 49. The power supply 49 is used to detect the occurrence of water leakage from the water shielding layer 7 and the water leakage position. When water leakage occurs, the leakage current flowing along the leakage current path caused by water leakage is detected by a current measuring means such as an ammeter 41. Although the electrometer 40 directly measures the potential at both ends of the input / output terminals of the power supply 49, since the resistance of the conductive wire connected to the power supply 49 is low, the point electrode 47 and the upper inspection electrode 48 are used. A potential corresponding to the potential difference between the two is applied. The electrometer 40 may be connected to any portion as long as the potential difference between the point electrode 47 and the upper inspection electrode 48 can be measured. Moreover, in order to shorten the time required for water leakage detection, a plurality of electrometers may be prepared, and a plurality of electrometers may be connected to each point electrode 7.

  Also, the electrode switching means 43 shown in FIG. 9 is connected between the power source 49 and the point electrode 47, and provides a leakage current path between the upper inspection electrode 48 and one of the plurality of point electrodes 47. To be formed. Further, the electrode switching means 43 selects one point electrode 47 connected to the upper inspection electrode 48 by a control device described later, and performs switching connection. In the water-blocking structure shown in FIG. 9, the distance between the upper inspection electrode 48 and the point electrode 47 in the ground 1 is switched by switching the point electrode 47 connected to the upper inspection electrode 48 by the electrode switching means 43. Is different. That is, a plurality of leakage current paths having different resistance values are formed, and a plurality of leakage current paths having different current intensities extending from the water leakage location to the selected point electrode 47 can be formed.

  In the water-impervious structure shown in FIG. 9, a plurality of leakage current paths are formed by sequentially switching the point electrodes 47 across the water-impervious portion by the electrode switching means 43, and the location of the water leak is specified.

  However, in order to monitor the reference current Ir by using a power source such as a constant current power source and providing a reference electrode 51 in the ground 1 or on the ground surface sufficiently away from the waste disposal site in order to measure the water leakage location more accurately. The power source 49 and the upper inspection electrode 48 may be connected via the ammeter 52 and the electrode switching means 43. In the example shown in FIG. 9, the reference electrode 51 is disposed in the ground 1 and can be arbitrarily turned on / off by the electrode switching means 43.

  Further, in the water shielding structure shown in FIG. 9, the point electrodes 47 are arranged at a constant interval a as shown in FIG. Although the space | interval a is not specifically limited, It is preferable to arrange | position with the space | interval which can detect a water leak position with the precision required in this invention, for example, it is set as the distance between 5m-10m. be able to.

  In the water shielding structure shown in FIG. 10, an ammeter 41, a power source 49, and an electrode switching unit 43 are connected in order from the upper inspection electrode 48. The ammeter 41 measures the intensity of the leakage current and sends this measured value to the control means 44. The control means 44 stores the two-dimensional position of the point electrode 47 and the intensity of the leakage current in the recording means.

  As the control means 44, a personal computer can be used. Control of the power source 49, control of the electrode selection operation of the electrode switching means 43, operation control of the electrometer 40 and reading of measured values, reading of measured values of the ammeter 41 Etc. Moreover, the control means 44 is equipped with the program for determining a water leak detection and a water leak position from the measured electric current distribution, and is performing generation | occurrence | production of a water leak and determination of a water leak position.

  The power source 49 may be a DC power source or an AC power source, and a constant voltage power source, a constant current power source, or a combination of a constant voltage power source and a constant current power source may be used as appropriate. The electrometer 40 is connected to an input / output terminal of a power source 49, and measures the potential applied between the point electrode 47 and the upper inspection electrode 48 at the time of water leakage detection operation.

  Further, the power source 49 is connected to the electrode switching means 43. The electrode switching means 43 is controlled by the control means 44 so as to selectively switch and connect one point electrode 47 to form one leakage current path between the one point electrode 47 and the upper inspection electrode 48. The control means 44 may connect the power source 49 to all the point electrodes 47 and form a plurality of parallel leakage current paths between the upper inspection electrode 48 and all the point electrodes 47. It may be controlled.

  Next, a method for detecting leakage of the water-impervious structure shown in FIG. 9 will be described.

  In the water-blocking structure shown in FIG. 9, when a leakage current path through the leakage point is formed between the upper inspection electrode 48 and the point electrode 47, the leakage current I flows. This leakage current I is detected by the ammeter 41, and after A / D conversion is performed, the current intensity is recorded by the control means 44.

Next, the electrode switching means 43 is switched and connected, so that the point electrodes 47 are sequentially switched over the water shielding portion to form a plurality of leakage current paths. The plurality of leakage current paths formed in this way have higher resistance values as they are farther from the water leakage location. In addition, the current distribution can be obtained by plotting the leakage current over the entire water shielding portion using all the point electrodes 47. This current distribution gives a sharp structure centered on the leakage current I ₁ closest to the leakage point, and the leakage position can be determined with high accuracy.

  Furthermore, in the above water leakage detection method, the ratio represented by the following formula (1) between the leakage current I flowing through the point electrode 47 and the reference current Ir flowing between the reference electrode 51 and the upper inspection electrode 48 described above. It is also possible to determine the location of water leakage more accurately using K.

  That is, the current Ir flowing between the reference electrode 51 and the power source 49 is always measured by the ammeter 52. Next, the point electrode 47 is switched point by point to measure the leakage current. Among the point electrodes 47, the point electrode closest to the water leakage point has a larger leakage current I compared to the current Ir flowing between the reference electrode 51 and the power source 49, and therefore the ratio K given by the above equation (1). Will grow. On the other hand, at the point electrode far from the leak location, the leak current I approaches Ir and becomes approximately 1 magnitude. Therefore, it is also possible to obtain the K value for all the point electrodes 47 to obtain the distribution of the K value, and to set the position where the K value becomes the maximum value as the water leakage position.

  In addition, the reference electrode 51 is sufficiently separated so as not to be affected by water leakage from the water shielding portion, and when the water leakage occurs, a maximum value is always formed at the water leakage position. By doing so, it becomes possible to correct the influence of fluctuations in the groundwater level of the ground 1, and the leakage current is plotted by plotting the leakage current as a distribution of K and interpolating using a spline function or the like. It is possible to estimate.

  Moreover, in this embodiment, since the electroconductive nonwoven fabric 5a, 5b is provided in the whole outer surface of the junction part 7c, and the whole slope of a recess among the outer surfaces of a water-impervious sheet, the outer surface and concave part of the junction part 7c are provided. The electricity can flow reliably over the entire slope.

  As described above, according to the water-impervious structure of the fourth embodiment, it is possible to quickly detect the intrusion of sewage contaminated by the discarded waste into the ground, and to influence the specific resistance distribution of the ground and the waste. It is difficult to receive, and it is possible to accurately determine the water leakage position.

  Further, in the water-impervious structure and the water leakage detection method of the fourth embodiment, similarly to the first embodiment, the outer surface and the recess of the joint portion 7c, which are regions where detection failures are likely to occur and regions where water leakage is likely to occur. Water leakage across the slope is reliably detected. Therefore, the water leakage detection of the water shielding layer 7 is excellent in reliability. And compared with the case where the electroconductive nonwoven fabric 5a, 5b is provided in the whole outer surface of the water-impervious layer 7, the usage-amount of the electroconductive nonwoven fabric 5a, 5b is small, and construction is also easy.

It is the schematic sectional drawing which showed an example of the waste disposal site to which the impermeable structure of this invention was applied. It is the top view which expanded and showed a part of water-impervious structure shown in FIG. It is sectional drawing which expanded and showed a part of water-impervious structure shown in FIG. It is the top view which expanded and showed a part of water-impervious structure shown in FIG. It is sectional drawing which expanded and showed a part of water-impervious structure shown in FIG. It is the schematic sectional drawing which showed the other example of the waste disposal site to which the impermeable structure of this invention is applied. It is the schematic sectional drawing which showed the other example of the waste disposal site to which the impermeable structure of this invention is applied. It is the top view which expanded and showed a part of water-impervious structure shown in FIG. It is the schematic sectional drawing which showed the other example of the waste disposal site to which the impermeable structure of this invention is applied. It is the top view which expanded and showed a part of water-impervious structure shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ground 2 ... Lower electrode 3 ... Coating layer 3a, 3b ... Resin sheet 3c ... Seam 4 ... Sand layer or covering soil 5a, 5b ... Conductive nonwoven fabric 6 ... Soil impermeable layer 7 ... Impermeable layer 7a, 7b ... Water shielding sheet 7c ... Junction part 8,31 ... Bottom part 9,39,49 ... Power supply 10 ... Current measuring means 12 ... Lower nonwoven fabric 13 ... Upper nonwoven fabric 14 ... Conductive material 15 ... Conducting part 15a ... Upper layer side portion 15b ... Lower layer side portion 15c ... Intermediate portion 20, 38, 82 ... Lower inspection electrode 21, 37, 81, 48 ... Upper inspection electrode 22 ... Constant current power source 23, 30 ... Current measuring means 24 ... Computer system 25 ... Control device 27 ... Drain 28 ... upper part 29 ... detection electrode 33 ... waste 37a ... movable detection electrode 47 ... point electrode 43 ... electrode switching means 40 ... electrometer 41, 52 ... ammeter 51 ... reference electrode a ... interval 44 ... control means I ... leakage current Ir ... see Flow

Claims (11)

A water-impervious structure including a water-impervious portion provided along a recess in the ground,
The water shielding portion is provided with an insulating water shielding layer, an upper electrode provided on the inner side of the water shielding layer, used for detecting water leakage of the water shielding layer, and provided on the outer side of the water shielding layer. And a lower electrode used for water leakage detection of the water shielding layer,
The lower electrode includes a first conductive layer provided over the entire outer surface of the water shielding layer,
A water shielding structure comprising: a second conductive layer electrically connected to the first conductive layer and provided only on a part of an outer surface of the water shielding layer. The water shielding layer is formed by joining a plurality of water shielding sheets,
The water shielding structure according to claim 1, wherein the second conductive layer is provided at least on an outer surface of a joint portion formed by joining adjacent water shielding sheets.   The water shielding structure according to claim 1, wherein the second conductive layer is provided at least on a slope portion of the recess.   The water-impervious structure according to any one of claims 1 to 3, wherein the second conductive layer is a conductive nonwoven fabric.   The water-impervious structure according to claim 4, wherein the conductive nonwoven fabric is a nonwoven fabric containing carbon.   The water-impervious structure according to claim 1, wherein the second conductive layer is an aluminum sheet. A third conductive layer outside the lower electrode;
Between the lower electrode and the third conductive layer, there is provided a coating layer that has an insulating property and covers the third conductive layer, and the lower electrode and the third conductive layer are electrically connected. The water-impervious structure according to claim 1, further comprising a conductive portion that is connected in an electrically connected manner. A plurality of detection electrodes in conduction with the upper electrode;
A power source for supplying current to the upper electrode and the lower electrode;
Current measuring means for measuring current flowing through the plurality of sensing electrodes,
Supplying a current to the lower electrode to measure a current flowing through the plurality of sensing electrodes;
Supplying current to the upper electrode, and measuring the current flowing through the plurality of sensing electrodes;
Detecting leakage of the water shielding layer by comparing a distribution shape of a current distribution obtained when a current is supplied to the lower electrode and a distribution shape of a current distribution obtained when a current is supplied to the upper electrode. The water-blocking structure according to any one of claims 1 to 6, wherein A plurality of upper inspection electrodes electrically connected to the upper electrode;
A power supply for supplying current to the lower electrode;
Current measuring means for measuring a current flowing through the plurality of upper inspection electrodes,
7. The computer system according to claim 1, further comprising: a computer system that sums the currents flowing through the plurality of upper inspection electrodes measured by the current measuring unit and detects water leakage in the water shielding layer. The water shielding structure according to any one of the above. The lower electrode includes a plurality of point electrodes,
An upper inspection electrode electrically connected to the upper electrode;
A power source for passing a current between the point electrode and the upper inspection electrode;
Current measuring means for measuring a leakage current caused by water leakage of the water shielding layer;
Electrode switching means;
Control means for forming different leakage current paths between the upper inspection electrode and the point electrodes;
The water-blocking structure according to any one of claims 1 to 6, wherein a water leakage location is detected by a current distribution of the leakage current flowing through the leakage current path over the entire area of the water-blocking layer. A water leakage detection method for detecting water leakage of the water shielding structure according to any one of claims 1 to 10,
A water impermeable detection method, comprising: detecting leakage of the water impermeable layer by conducting between the upper electrode and the lower electrode.

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