JPH1099810A - Sheet damage detection device in water barrier construction equipment of waste final disposal plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect whether a sheet is damaged without requiring a state change in a double sheet segment itself and to eliminate the possibility of corrosion over a long period of time. SOLUTION: When a double sheet segment 12 is damaged, water leaks from a damaged place to enter the interior of the double sheet segment 12 but, at this time, the water leak of a disposal plant shows high electric conductivity. Therefore, when an electric insulating material is used as a buffer material 15 and upper and rear electrode plates 16, 17 are arranged to both surfaces thereof and appropriate voltage is applied across the electrode plates 16, 17 to measure electrical characteristics (e.g; electric resistance value or electric capacity value) are measured, a stable electrical characteristic value determined by the properties of the buffer material 15 is shown in a damage free state but, in such a state that leaked water enters by damage, the upper and rear electrode plates 16, 17 become a substantially electrical short-circuit state and the electrical characteristic value between the electrode plates 16, 17 is largely changed. By detecting the change of the electrical characteristics, it can be detected whether the upper water barrier sheet 13 of the double sheet segment 12 is damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet damage detection system in a seepage control facility at a final waste disposal site.

[0002]

2. Description of the Related Art Regarding waste treatment, recycling is promoted as much as possible from simple burning and burying, with the aim of achieving a recycling-free waste-free society. Although it is being used, it is said that the generated residues must be landfilled in a manner that does not hinder the living environment.

[0003] With regard to the structure of the final waste disposal site used for this purpose, administrative guidance is given to provide impermeable construction as necessary so that leachate does not contaminate public waters and groundwater. In other words, at the final disposal site of garbage, a water-impermeable sheet with non-permeability is landfilled so that rainwater that dissolves harmful and toxic substances that permeate the waste and adversely affect the environment does not enter the groundwater vein. A water-blocking work is applied to the lowermost surface of. The area of the final waste disposal site is
For example, to cover an area of 10,000 m ² , the impermeable sheet is segmented in a size of about 50 to 100 m ² ,
A number of impermeable sheet segments are laid continuously throughout the disposal site.

Here, in order to further secure safety and reliability, regarding the final disposal site improvement project newly started from 1997, the water shielding It is recommended to double the impermeable sheet and lay a drainage layer between them.

This is to prevent the discarded material from breaking through the soil cover and the impermeable sheet, but it is not perfect even with the double structure of the impermeable sheet. , Waste handling vehicles, mishandling, boulders, etc.), and constantly detects the presence or absence of damage to the impermeable sheet, and if any damage is detected, immediately It is essential to take measures to repair the impermeable sheet.

Various methods have been proposed or are currently being implemented as a method for detecting the presence or absence of damage to the impermeable sheet.

As a first example, for example, there is a double sheet vacuum management system known as "T & OH system" manufactured by Taiyo Kogyo Co., Ltd. ("City and Waste Vol. 2").
6. No. 1 ", p. 65-68). The outline is that each double sheet (segment) processed into a bag is evacuated with a vacuum pump to apply vacuum pressure and observe the temporal change in the degree of vacuum. The air can flow into the segment and the degree of vacuum is lost, so that damage can be detected, and the segment can be dealt with by urgently applying pressure and injecting repair material. is there.

[0008] As a second example, there is, for example, a system for detecting a damaged position of a seepage control sheet known as "Sensor DDS" manufactured by Taiyo Kogyo Co., Ltd. (see the catalog of the company).
The outline will be described with reference to FIG. This method can be said to be a so-called under-sheet sensor method, in which electrodes 3 and 4 are arranged outside and inside a water-insulating sheet 2 having electrical insulation laid in a final disposal site 1. A constant current device 5 is connected between the electrodes 3 and 4 to allow a current to flow.
a, 6b,..., 6n are embedded at equal intervals and connected to the control box 8 via a cable 7. As a result, when a current flows between the electrodes 3 and 4, if the water-blocking sheet 2 is not damaged, the current does not flow because the water-blocking sheet 2 has electrical insulation. However, if the impermeable sheet 2 is damaged as shown in the figure, a large amount of current will flow through the water leaking from the damaged portion 9, and FIG.
As shown in (b), the potential near the damaged portion 9 changes.
Therefore, the potential difference between the electrodes of the measurement electrode 6 embedded in the lower part of the water-impervious sheet 2 is measured on the control box 8 side via the cable 7, and the obtained data is analyzed by a computer, so that the water-impervious sheet is analyzed. 2 can be located. Although FIG. 5 shows an example of a single sheet structure, the same applies in principle to a double sheet structure.

[0009]

However, in the case of the first vacuum system, it is possible not only to detect the sheet damage but also to repair it, but it is necessary to perform vacuum / evacuation processing on a large number of double sheet segments. Since the state of the double sheet segment is changed, there are inconveniences such as an increase in equipment size, an increase in equipment cost, and a risk of pipe leakage. Furthermore, the measurement time is longer because the degree of vacuum changes over time, and the detection workability is not very good. Especially,
It is necessary to continue the detection operation regularly for a long period of several decades or more after the installation of the equipment, and when the final disposal site is full, the weight on the double sheet segment will be considerable, Performing a vacuum process on each double sheet segment in such a state places an excessive load on the vacuum pump.

Further, in the case of the second under-sheet buried sensor system, although the water-impervious sheet itself can be detected without a change in state, a large number of measurement electrodes 6a, 6b,. Since the end of the electric wire is buried underground in the final disposal site 1, its corrosion resistance becomes a problem and its reliability is lacking. In particular, considering that the detection operation needs to be continued periodically for a long period of several decades or more after the installation of the equipment, the measurement electrodes 6a, 6b,.
It is considered difficult to prevent corrosion of n. Furthermore, to increase the accuracy of the measurement, it is necessary to stabilize the earth resistance.However, there is no guarantee that the earth resistance of the site will be stable over a long period of time. There is a disadvantage that it is easy to do.

Therefore, the present invention provides a waste sheet which can detect the presence or absence of sheet damage without requiring a change in the state of the double sheet segment itself, and has a stable measurement accuracy without worrying about corrosion resistance over a long period of time. An object of the present invention is to provide a sheet damage detection system in a seepage control facility at a disposal site.

[0012]

According to the first aspect of the present invention,
A final waste disposal site where multiple double sheet segments processed into a bag with a water-permeable cushioning material sandwiched between the upper and lower water-impervious sheets are continuously laid throughout the disposal site. In the water impervious construction equipment, electrical insulating materials are used for the upper water-impervious sheet, the lower water-impervious sheet and the cushioning material, and the upper electrode plate and the lower electrode plate are arranged in each double sheet segment via the cushioning material. A voltage was applied between the upper electrode plate and the lower electrode plate forming a pair at an appropriate point in time, and a change in electrical characteristics between these electrode plates was detected to detect damage to the impermeable sheet. According to a second aspect of the present invention, each of the upper water-impervious sheet, the lower water-impervious sheet, and the buffer is made of an electrically insulating material, and the upper electrode plate is disposed in each double sheet segment via the buffer. Measuring means for applying a measurement voltage between a lower electrode plate and at least a pair of an upper electrode plate and a lower electrode plate which are individually wired and connected to each of the upper electrode plates to measure electrical characteristics between the electrode plates In the double sheet segment in which the electrode plate is incorporated by comparing the electrical characteristic value measured by the measuring means between a pair of electrode plates to which the measurement voltage is applied and a predetermined reference value. A determining means for determining whether or not the impermeable sheet is damaged;

Generally, when a double sheet segment laid at a disposal site is damaged, water leaks from the damaged portion into the double sheet segment. At this time, there is a high possibility that the leakage due to rainwater or the like at the final disposal site contains a metal component, and the electric conductivity thereof is considerably higher than that of natural water. Therefore, in the present invention, an electrically insulating material is used as a buffer material, and a double sheet segment structure in which an upper electrode plate and a lower electrode plate are disposed on both surfaces thereof is applied by appropriately applying a voltage between the electrode plates. When the electrical characteristics between the electrode plates are measured, when there is no damage, it shows stable electric resistance value and electric capacitance value determined by the properties of the buffer material, etc., but when the water is damaged and water leaks, the water leakage is high. In order to show the electric conductivity, the upper electrode plate and the lower electrode plate are substantially electrically short-circuited, and the electric resistance value and the electric capacitance value between the electrode plates change greatly. Therefore, by detecting such a change in the electrical characteristics, it is possible to detect whether or not the waterproof sheet of the double sheet segment has been damaged. Only the electrical properties need to be measured, and the double sheet segment itself does not need to change state. Further, since the electrode plate is built in the double sheet segment, a state free from corrosion can be maintained for a long time, and a stable measurement is possible and a highly reliable detection system is provided.

Here, in the present invention, the upper electrode plate has a size of substantially 1
It may be a single plate, or it may be divided like a matrix in each double sheet segment, and the wiring may be drawn out from each of them. Further, in the present invention, “electrical characteristics” between the electrode plates typically means the above-described electric resistance and electric capacity, but the presence or absence of leakage of water into each double sheet segment. It is only necessary that the electrical characteristics change in accordance with the conditions and that the characteristics can be measured electrically. As a method of measuring the electrical characteristics between all the paired electrode plates in the measuring means, for example, using only one measurement system, sequentially between the paired upper electrode plate and the lower electrode plate In addition to the scanning measurement method in which measurement is performed by applying a measurement voltage, a so-called continuous measurement method in which a required number of amplifiers or detection circuits are prepared in accordance with the number of electrode plate pairs and their measurement outputs are sequentially taken out may be used. . In the case of using the scanning measurement method, each upper electrode plate is assigned an address for specifying its laying point in the entire disposal site,
By scanning and measuring the electrical characteristics according to the address, the location where the damage is detected can be specified.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a perspective view schematically showing an example of a final waste disposal site. In a disposal site 11 having an area of, for example, 10,000 m ² , which is appropriately dented by utilizing the terrain or created, the original land is used. After forming a layer of protective sand (not shown) over the entire surface of the ground, a large number (N) of double sheet segments 12 are continuously laid without any gaps in the front-rear and left-right directions, so that the water is impermeable. Construction facilities are provided. Laminated double sheet segment 12
Is entirely covered with a layer of protective sand.

Here, a number of double sheet segments 12
Any two of them will be extracted and the structure will be described with reference to FIG. First, the double sheet segment 12 is used for the upper impermeable sheet 1.
3 and the lower water-impervious sheet 14 are formed by processing into a bag with a water-permeable cushioning material 15 interposed therebetween, and one double sheet segment 12 is, for example, 50 to 1
It is formed in a substantially rectangular shape with a size of 00 m ² . Up,
The lower water-impervious sheets 13 and 14 may be made of a material that is impermeable to water, has a strength that is not easily damaged by a simple mechanical force, and has an electrical insulating property.
For example, a rubber sheet or a plastic sheet such as polyethylene or urethane is used. However, since it is difficult to manufacture a single sheet of the size as described above, in reality, several strip-shaped sheets are joined together in the construction site in a state where they can maintain non-water-permeability in the horizontal direction as a desired size. I have. The cushioning material 15 is made of a porous material such as a loofah, has water permeability, and is formed of a material having electrical insulation. In particular,
A non-woven cloth or the like that makes the double sheet segment 12 difficult to tear is used. Although not shown, the adjacent double sheet segments 12 are bonded together by a well-known bonding technique so as to maintain the water impermeability therebetween.

In such a double sheet segment 12, the inner surfaces of the upper and lower water-impervious sheets 13, 14 and, hence, both surfaces of the cushioning material 15, are provided on the upper electrode plate 1 having a size substantially over the entire surface.
6 and a lower electrode plate 17 are incorporated. The upper and lower electrode plates 16 and 17 need only be an electrically good conductor, may be made of metal or conductive plastic, and may be plate-like or film-like. 0.
An aluminum foil having a thickness of 2 to 0.3 mm is used. further,
Lead wires 1 connected to the upper and lower electrode plates 16 and 17
8 and 19 are subjected to insulation treatment and water impermeability treatment, and are drawn out from the upper and lower waterproof sheets 13 and 14, respectively. Here, the lower electrode plate 17 side is a common electrode side grounded in all the double sheet segments 12, and the lower electrode plates 17 of the adjacent double sheet segments 12 are connected to each other by lead wires 19 as appropriate. It is grounded at any one or several places. On the other hand, the upper electrode plate 16 side is an individual electrode side to which the measurement voltage is independently applied in all the double sheet segments 12, and the lead wire 18 drawn from each upper electrode plate 16 is connected to the disposal site 11. The wiring is individually wired to the control box 20 installed in the management wing or the like. In the state shown in FIG. 1 and the like,
The rising portion of the lead wire 18 is shown in an exaggerated state and is different from the actual mounting state.

In the present embodiment, a measuring system is configured by a scanning measuring method. In the control box 20, any upper and lower electrode plates 16, 1 are provided.
A scanning measuring circuit (measuring means) 22 having a power supply 21 for applying a measuring voltage between the electrodes 7 and measuring the electrical characteristics between the electrode plates 16 and 17, and the measuring voltage is measured by the scanning measuring circuit 22. By comparing the applied and measured electrical characteristics between the lower electrode plates 16 and 17, for example, the electrical resistance value and the electrical capacitance value, with a preset reference value, the damage of the upper water impermeable sheet 13 is reduced. A determination circuit (determination means) 23 for determining the presence or absence is provided. Here, the N double sheet segments 12 (accordingly, the upper electrode plate 16) laid over the entire surface of the disposal site 11 are addressed from 1 to N corresponding to the laying positions, and are assigned to the control building. It is associated with an address map. In the scanning measurement circuit 22, these N upper electrode plates 1
With respect to No. 6, for example, it is set so that the measurement voltage is sequentially applied at the detection timing while scanning the electrode plates one by one in the address order. Such a scanning operation is set to be performed once or several times a day, and to be performed periodically for several tens of years.

In such a configuration, when the detection timing comes, the scanning measurement circuit 22 applies a measurement voltage to each of the upper electrode plates 16 sequentially and individually. The resistance value and the capacitance value are detected. Here, in a state where the double sheet segment 12 to be scanned is not damaged, a stable electric resistance value and electric capacitance value determined by the properties, thickness, dimensions (size) of the cushioning material 15 having electrical insulation properties. Is shown. For such an electric resistance value and an electric capacity value, the determination circuit 23 outputs a normal signal indicating that no damage has occurred. On the other hand, when the double sheet segment 12 to be scanned is damaged due to an object piercing the upper waterproof sheet 13 or the like, water leaks into the double sheet segment 12 from the damaged portion.
Here, there is a high possibility that the leakage due to rainwater or the like at the disposal site 11 contains a metal component, and the electric conductivity thereof is considerably higher than that of natural water. Therefore, although a buffer material having an electrical insulation property is interposed between the upper and lower electrode plates 17 and 18, the upper and lower electrode plates 17 and 18 are substantially reduced due to leakage of water having high electric conductivity. As a result, the electrical resistance value and the electrical capacitance value between these electrode plates 17 and 18 greatly change. Therefore, by comparing the detected electric resistance value and the detected electric capacity value with the reference value in the judgment circuit 23, it is judged that the upper impermeable sheet 13 is damaged in the double sheet segment 12, and the abnormal signal is output. Is output. At this time, the administrator determines which address of the double sheet segment 12 (upper electrode plate 1).
3) Since it is known whether or not damage has been detected in the portion, the portion to be repaired can be found by comparing the damage with the address map.

Therefore, according to the present embodiment, a change in the electrical characteristics between the electrode plates 16 and 17 in the double sheet segment 12 caused by whether or not water leaks into the double sheet segment 12 is utilized. In order to detect the presence or absence of damage, the double sheet segment 12 itself does not need to be changed in state such as vacuuming at the time of detection, and equipment that requires a large-scale equipment such as a vacuum pump and a pressure gauge and requires high equipment costs is required. do not do.
Further, at the time of measurement, since the measurement is performed based on the electrical change when the measurement voltage is applied, the measurement time can be shortened. Furthermore, although the upper and lower electrode plates 16 and 17 are used, they are built in the double sheet segment 12 and are not exposed in the ground or the like. And a highly reliable detection system.

In the present embodiment, an example in which only a pair of electrode plates 16 and 17 are formed for each double sheet segment 12 has been described. in the upper electrode plate 16 _n1 ~ 16 _nm is divided into m in a matrix as shown in FIG. 4, in correspondence with each of the upper electrode plate 16 _n1 ~ 16 _nm and the lead wires 18 may lead wires 18 _n1 ~ Control box 2 individually at 18 _nm
You may draw out to 0. In this case, the lower electrode plate 17 side may be divided in the same manner, but they are mutually connected to the ground, and in consideration of the wiring processing and the like, a single lower electrode plate 17 is used. Is good. In this case, addressing is performed by dividing the upper electrode plates 16 _{n1 to} 16 _n1
nm have been made for each, its is to correspond to the laying location addressed from 1 _n1 to N _nm is done, it is associated with the address map in the control house. The scanning measurement circuit 22 is set so as to sequentially apply a measurement voltage to these N upper electrode plates 16 while scanning the electrode plates one by one in the address order at the detection timing, for example. According to this division method, the _lead wire 18 _n1
Although the number of lines of ~ 18 _nm increases and the processing becomes difficult, the detection area is narrowed down to a narrower range than when the double sheet segment is 12 units, so that if damage is detected, the location is specified in more detail. be able to.

In the present embodiment, the measuring system has a time-series scanning measuring method. However, the present invention is not limited to this method, and the number of amplifiers or detecting circuits may be set to a required number corresponding to the number of electrode plate pairs. A so-called continuous measurement method or the like that prepares and sequentially takes out the measurement outputs may be used. In short, it suffices if the electrical characteristics of all the electrode plate pairs can be measured.

[0023]

According to the first aspect of the present invention, a plurality of double sheet segments processed into a bag shape with the upper water-impervious sheet and the lower water-impervious sheet sandwiching a water-permeable cushioning material are disposed of. In the seepage control facility of the final waste disposal site, which is continuously laid throughout the site, electric insulating materials are used for the upper waterproof sheet, the lower waterproof sheet, and the cushioning material. Arrange the upper electrode plate and the lower electrode plate in the heavy sheet segment,
A voltage is applied between the upper electrode plate and the lower electrode plate forming a pair at an appropriate point in time to detect a damage of the water-impervious sheet by a change in electrical characteristics between these electrode plates. According to the invention, each of the upper water-impervious sheet, the lower water-impervious sheet, and the cushioning material is made of an electrically insulating material, and the upper electrode plate and the lower electrode plate are disposed in each double sheet segment via the cushioning material. Measuring means for applying a measurement voltage between the upper electrode plate and the lower electrode plate forming a pair by being individually wired and connected to at least each upper electrode plate, and measuring an electrical characteristic between the electrode plates, Comparing the electrical characteristic value measured by the measuring means between a pair of electrode plates to which a voltage is applied with a predetermined reference value, and a waterproof sheet in the double sheet segment in which the electrode plate is built. Determining means for determining the presence or absence of damage to the The presence or absence of damage is detected by utilizing the fact that electrical characteristics such as electrical resistance between the upper and lower electrode plates in the double sheet segment change depending on whether or not water leakage from the disposal site enters the sheet segment. As a result, only the electrical measurement is required, and the double sheet segment itself does not require a change in state such as vacuuming for detection, and is large-scale including a vacuum pump, a pressure gauge, etc., and is expensive. No equipment is required, and at the time of measurement, the measurement is made based on the electrical change when the measurement voltage is applied, so it can be measured in a short time, and the upper and lower electrode plates are built in the double sheet segment. Since it is not exposed under the ground, it is possible to maintain a state free from corrosion for a long period of time and to provide a highly reliable detection system capable of performing stable measurement.

[Brief description of the drawings]

FIG. 1 is a perspective view of a double sheet segment showing one embodiment of the present invention.

FIG. 2 is a perspective view showing a seepage control facility in a final waste disposal site.

FIG. 3 is a block diagram showing a measurement system.

FIG. 4 is a perspective view showing a modification.

5A and 5B show a conventional example, in which FIG. 5A is a schematic sectional view, and FIG.
FIG. 4 is a characteristic diagram showing a state of potential displacement.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Disposal site 12 Double sheet segment 13 Upper impermeable sheet 14 Lower impermeable sheet 15 Buffer material 16 Upper electrode plate 17 Lower electrode plate 22 Measurement means 23 Judgment means

Claims (2)

[Claims] 1. A plurality of double sheet segments processed into a bag shape with a water-permeable cushioning material sandwiched between an upper water-impervious sheet and a lower water-impervious sheet are continuously laid over the entire disposal site. In the seepage control facility of the final waste disposal site, an electrical insulating material is used for the upper seepage control sheet, the lower seepage control sheet and the cushioning material, and the upper electrode plate is provided in each double sheet segment through the buffering material. A lower electrode plate is provided, and a voltage is applied between the upper electrode plate and the lower electrode plate forming a pair at an appropriate time to detect damage to the impermeable sheet by a change in electrical characteristics between these electrode plates. A sheet damage detection system in a seepage control facility at a final waste disposal site, characterized in that: 2. Disposal of continuously laying a plurality of double sheet segments formed into a bag shape with a water-permeable cushioning material sandwiched between an upper water-impervious sheet and a lower water-impervious sheet over the entire disposal site. In the seepage control facility at the final disposal site, the upper sheet, the lower sheet, and the cushioning material are made of an electrically insulating material, and are disposed in each double sheet segment via the cushioning material. A measurement voltage is applied between the upper electrode plate and the lower electrode plate forming a pair by being individually connected to the electrode plate and the lower electrode plate and at least each upper electrode plate, and the electrical characteristics between the electrode plates are measured. Measuring means, and comparing the electrical characteristic value measured by the measuring means between a pair of electrode plates to which a measurement voltage is applied, with a preset reference value, and incorporating the electrode plate therein. Determine whether the impermeable sheet is damaged in the sheet segment Sheet damage detection system in final waste disposal site water barrier Engineering equipment, characterized by comprising a constant means.