JPH10104111A - Equipment to check for leaks in buried pipes - Google Patents

Abstract

(57) [Summary] [Purpose] To make it easy to find the location of water leakage in buried pipes. In an apparatus for electrically inspecting a waterproof material 11 for covering a buried pipe 10 for water leakage, an external current electrode 21 disposed outside the waterproof material 11, an internal current electrode 22 disposed on the buried pipe 10, A measuring electrode for measuring a potential in the vicinity of the surface of the waterproof material; and determining a water leakage position of the waterproof material from the distortion of the potential distribution on the surface of the waterproof material measured by the measuring electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection for leaking water from a buried pipe.

[0002]

2. Description of the Related Art Conventionally, there is no practical device for detecting water leakage from a buried pipe. Therefore, it is visually confirmed that water has spouted from a joint of a segment or the like, and a waterproofing agent is injected from a grout inlet to extend the length. Measures were taken to stop the water in the entire waterproof section of about 20 m.

However, the conventional method has the following problems. <B> If the waterproof sheet covering the buried pipe is damaged and leaks water, the damaged point is on the back side of the segment, so the damaged point cannot be seen, and water leaking between the segment and the impermeable sheet turns around, Since water leaks into the mine from the joint of the segment with weak water stoppage, it is not possible to identify where water is leaking anywhere in the waterproof compartment provided at intervals of about 20 m in length. Can not. <B> In the case where the waterproof sheet is damaged, the method of visually inspecting and detecting the presence or absence of water leaking into the mine is based on the method that the generated water leaks from the weakly water-tight place such as a joint of the segment into the mine. Because it cannot be found, it cannot be found during construction, and there is a problem that the water pressure around the building after completion increases and suddenly water leaks in the mine.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to easily find a leak position of a buried pipe.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an apparatus for electrically inspecting a waterproof material covering a buried pipe for leakage of water, wherein an external current electrode disposed outside the waterproof material and an internal current electrode disposed in the buried pipe are provided. An electrode, a voltage applying means for applying a voltage between the internal current electrode and the external current electrode, and a measuring electrode for measuring a potential near a surface of the waterproof material, and a potential on the surface of the waterproof material measured by the measuring electrode. In the device for inspecting the leak of a buried pipe, or the device for inspecting the leak of a buried pipe, wherein a leak position of the waterproof material is obtained from the distortion of the distribution, a reinforcing bar of the buried pipe is used as an internal current electrode. In a device for inspecting a leak of a buried pipe, or a device for inspecting a leak of a buried pipe, the shield machine body is used as an external current electrode, wherein the leak of the buried pipe is performed. Inspect Apparatus, or in the apparatus for inspecting the leakage of the buried pipe, characterized in that the measurement electrode is disposed in the grout injection hole of the buried pipe, the apparatus for inspecting the leakage of the buried pipe, or the leakage of the buried pipe In the inspection device, the external current electrode is arranged on the outer wall surface of the buried pipe insulated from the buried pipe via an insulator, and the apparatus for inspecting the leakage of the buried pipe, or An apparatus for inspecting water leakage of a buried pipe, wherein the external current electrode is arranged on an outer periphery of the shield machine,
In the device for inspecting water leakage of a buried pipe, or the device for inspecting water leakage of a buried tube, the measuring electrode is arranged on the outer periphery of the segment, the apparatus for inspecting the leakage of buried pipe is provided. .

[0006]

Embodiments of the present invention will be described below with reference to the drawings. <A> Outline of device for inspecting water leakage of buried pipe The device for inspecting water leakage of the buried pipe 10 electrically checks whether or not the waterproof material 11 such as the waterproof sheet 31 covering the buried pipe 10 has been damaged and the damaged portion 15. It is to detect. Waterproof material 11
Since they generally exhibit electrical insulation, breakage is detected using electrical insulation.

FIG. 1 shows an outline of the detection of the presence or absence of water leakage and the location. Since the waterproof material 11 is usually arranged outside the buried pipe 10 (the segment 30 in the case of a shield tunnel), the waterproof material 11 is sandwiched between the buried pipe 10 and the ground 13. Both the ground 13 and the segment 30 are conductors (in the case of the ground 13 sufficiently containing water: 1 to 100 Ωm,
In the case of water-absorbing concrete 12: 20 to 100Ω
m), the insulator is electrically sandwiched between the conductors. Even if a voltage is applied between the ground 13 which is a conductor on both sides and the segment 30, no current flows unless the waterproof material 11 is damaged because the waterproof material 11 is an insulator.

However, as shown in the principle of FIG. 2, a voltage is applied by a power source 26 between the external current electrode 21 and the reinforcing bar 14 as the internal current electrode 22, and the flowing current is measured by an ammeter 27.
Measure with Then, when a break occurs in the waterproof material 11 and a hole is opened, the ground 13 and the segment 30 come into direct contact with each other through the hole (damaged portion 15) or indirectly contact with each other through water. A current flows between and segment 30. When this current is generated,
That is, distortion of the potential distribution centering on the damaged portion 15 occurs.

This situation is shown in FIGS. FIG. 3 shows the potential distribution when the waterproof material 11 is not damaged. Since no current flows inside and outside the waterproof material 11, there is no distortion in the potential distribution, and the potential is almost the same inside or outside the waterproof material 11. Become.

[0010] However, as shown in FIG.
If there is damage, the electric current flows in and out through the damaged part 15, so that the potential distribution around the damaged part 15 is distorted. The distortion of the potential distribution is represented by the segment 30
Potential measuring electrode 2 arranged in a mesh on the waterproof material 11 side
By catching at 5, it is possible to detect the position of the damage.

Further, if there is only damage, the ground 13
By calculating the current and the potential difference between the current and the segment 30, the insulation resistance therebetween can be determined, and it can be determined whether the waterproof material 11 is damaged.

Furthermore, when the potential difference between the ground 13 and the segment 30 generated by passing a current between the segment 30 and the ground 13 (inside and outside of the waterproof material 11) is not measured, that is, it is not determined whether the waterproof material 11 is damaged. In this case, even if the external reference electrode 23 is not provided, the presence or absence of damage and the position of the damage can be detected by a method of measuring the potential difference generated in the potential measurement electrode 25.

<B> Arrangement of Electrodes There are several methods for measuring the potential distribution. For example, a method in which the internal reference electrode 24 is provided for a large number of potential measurement electrodes 25 and the potential of each potential measurement electrode 25 is determined by the measuring device 20 based on the potential of the internal reference electrode 24. Only by plotting the measured voltage of the electrode 25, the equipotential diagram of FIG. 4 can be drawn. The potential distribution shown in FIG. 4 can be obtained by measuring the potential between the potential measurement electrodes 25 and taking an integral value of each measured value.

Further, if there is only damage, the waterproof material 1
It is also possible to judge from the magnitude of the current flowing through 1. That is, since the specific resistance of the waterproof material 11 can be determined by measuring it in advance, it is possible to predict how much current flows when there is no breakage depending on the thickness and area of the waterproof material 11.

If the waterproof material 11 is not damaged, the current flowing between the internal current electrode 22 and the external current electrode 21 can be predicted from the following equation (1).

[0016]

(Equation 1)

On the other hand, if the waterproof material 11 is damaged, a considerable amount of current flows from the damaged portion. Thus, a predetermined current value is determined, and when a larger current flows, the waterproof material 11 can be determined to be damaged. Since the presence or absence of breakage can be determined by this method, when it is determined that there is breakage, the potential distribution is measured to find the breakage point 15. As described above, if a two-step measurement method such as the measurement of the presence or absence of breakage and the measurement of the breakage point 15 is employed, efficient measurement can be performed.

[0018]

An embodiment will be described below with reference to the drawings.

<A> Embodiment 1 The reinforcing bar 14 of the segment 30 is used as the internal current electrode 22, the main body (particularly, the tail) of the shield machine 40 is used as the external current electrode 21, and the potential measuring electrode 25 is inserted into the grout injection hole. 5 to 6 show an example of setting.

An external reference electrode 23 is installed in a shaft 34,
The potential measurement electrode 25 is set in a mesh shape using the grout injection hole of the segment 30 within the measurement range. FIG.
When the grout injection hole is made of a metal fitting 36 that does not come into contact with the reinforcing bar 14 of the segment 30 as described above, the injection hole itself is used as the potential measurement electrode 25. In other cases, the potential measurement electrode 25 is inserted into the grout inlet 32 as shown in FIG. 8, for example.

The external reference electrode 23 and the measuring device 20 installed in the shaft 34 are connected to a rear bogie 43 on which the measuring device 20 is mounted.
Are connected via the electric wire drum 28 in order to proceed along the rail 41 with the excavation of the shield machine 40. Further, it is directly connected to the main body of the shield machine 40 used as the external current electrode 21 by an electric wire. The connection of the segment 30 used as the internal current electrode 22 to the reinforcing bar 14 and the installation of the potential measurement electrode 25 in the grout injection hole are performed for each measurement. The connection of the segments 30 to the reinforcing bars 14 is performed because the metal fittings connecting the segments 30 are welded to the reinforcing bars 14.
This is done by connecting wires to the connection fittings.

The insulation between the water leakage measurement ranges (between the waterproof sections 33) is performed by sandwiching a waterproof material, for example, a waterproof sheet, between the segments 30. At this time, the bolts connecting the segments 30 penetrate the waterproof sheet of the waterproof section 33. Therefore, in order to secure insulation between the waterproof sections 33, the connecting bolts penetrating the waterproof sheet are insulating bolts (resin coated). Bolts). In addition, the pipes, rails 41, and the like that traverse the waterproof section 33 are electrically insulated from the segments 30. For example, the plumbing wires 45 are insulated from the segment 30 by being received by the insulating hook 44, and the rail 41 is insulated by sandwiching a sleeper insulating material 46 such as rubber between the sleeper 42 and the segment 30. In addition, 35 is a temporary segment.

The above preparations are made, and an inspection for water leakage (breakage of the waterproof sheet) is performed. In the inspection, a current is applied to the internal current electrode 22 (the reinforcing bar 14 of the segment 30) and the external current electrode 21 (the main body of the shield machine 40), and the internal reference electrode 24
The current flowing in and out is controlled so that a constant voltage is generated between (any potential measuring electrode 25) and the external reference electrode 23.
In this state, the insulation resistance of the waterproof sheet 31 per unit area is determined from the current flowing in and out, the internal and external voltages (set value), and the area of the waterproof sheet using Equation 1 and compared with the characteristic value thereof. It is determined whether 31 is dielectric breakdown, that is, broken. If the waterproof sheet 31 is damaged, the insulation resistance is significantly lower than the insulation resistance inherent to the waterproof sheet 31.

Next, in this state (in a state where a current is flowing inside and outside), a potential distribution is measured outside the segment 30 by using a potential measuring electrode 25 arranged in a mesh shape. To identify. The measurement of leak detection is
There is a measurement for judging the presence or absence of breakage of the waterproof sheet based on the amount of current inside and outside, and a measurement for specifying a breakage position. Since it is not necessary to use the potential measurement electrode 25 installed in a mesh shape for the measurement of the inside and outside current amount, only the inside and outside current measurement is performed to determine whether the waterproof sheet is damaged, and only when there is a possibility of damage, There is also a measuring method in which the potential measuring electrode 25 is provided to specify a broken position.

<B> Embodiment 2 In the segment 30, the potential measuring electrode 25 and the internal current electrode 2
FIG. 9 shows an example of using the dedicated segment 30 in which 2 is set.
10 to FIG. At least one set of external current electrodes 21 and external reference electrodes 23 are attached to both side surfaces (or upper and lower outer surfaces) of the main body of the shield machine 40 via the main body and the insulating layer 47. At this time, the surfaces of the electrode and the insulating layer 47 are smoothed as the same curved surface as the main body of the shield machine 40. Further, the insulating layer 47 is provided for preventing both electrodes from short-circuiting via the main body of the shield machine 40, and either one of them can be omitted. The internal current electrode 22 is provided on the outer surface of the segment 30, as shown in FIG. At this time, a smooth outer surface is used so that the electrode surface and the outer surface of the segment 30 have the same curved surface. At least one (preferably two) internal current electrodes 22 are installed in the waterproof section 33 serving as one measurement range, and a plurality of potential measurement electrodes 25 are installed in a mesh shape to measure the potential distribution.

The measuring device 20 is mounted on a rear bogie 43 that advances with the excavation of the shield machine 40, and the external current electrode 21 and the external reference electrode 23 attached to the outer surface of the shield machine 40 are directly connected to the measuring device 20 by electric wires. . The connection between the potential measurement electrode 25 attached to the segment 30 and the internal current electrode 22 is made for each measurement because the measurement is performed for each waterproof section 33.

The insulation between the measurement ranges (between the waterproof sections 33)
As in the first embodiment, the waterproof sheet 31 is sandwiched between the segments 30, and the segment connecting bolts penetrating between the segments 30 are insulating bolts (bolts coated with resin). In addition, pipes and rails 4 that traverse the waterproof section 33
1 and the like are electrically insulated from the segment 30 as in the first embodiment.

The measurement of water leakage detection is performed in the same manner as in the first embodiment. A current is applied between the internal current electrode 22 and the external current electrode 21, and any of the internal potential measurement electrodes 25 and the external reference electrode 2 are used.
3 to control a current flowing in and out so that a constant voltage is generated. In this state, the insulation resistance of the waterproof sheet 31 per unit area is determined from the current flowing inside and outside, the inside and outside voltage (set value) and the area of the waterproof sheet, and this value is compared with the insulation resistance specific to the waterproof sheet. It is determined whether the waterproof sheet 31 is broken down, that is, whether it is damaged. Waterproof sheet 31
Is damaged, the insulation resistance is significantly reduced as compared with the eigenvalue. In this state, the electric potential distribution is measured using the electric potential measuring electrodes 25 arranged in a mesh shape on the outer tube of the segment 30, and the potential distribution is generated around the damaged position of the waterproof sheet 31 by using the potential distribution distortion. To identify.

In the above embodiment, the inner and outer reference electrodes 2
The current flowing between the inner and outer current electrodes 22 and 21 was controlled so that a constant voltage was generated between the electrodes 4 and 23. However, the present invention is not limited to this.
The same effect can be expected in principle by a method in which a constant current is passed between the inner and outer current electrodes 22 and 21 and the voltage generated between the inner and outer reference electrodes 24 and 23 is measured.

[0030]

According to the present invention, the following effects can be obtained. <A> In any place in the measurement range (in the waterproof section), the location of the leak can be accurately specified (position measurement accuracy of about 10% of the potential measurement electrode installation interval). Therefore, unlike the related art, it is not necessary to stop the entire waterproof section 33 in which the leak is detected, and the leak can be stopped by a local waterproofing measure. <B> If the waterproof sheet breaks even if there is no water leakage,
The presence and location of the damage can be immediately detected. For this reason, a quick countermeasure can be taken, and there is no problem that water leakage occurs after the inspection. In the past, if water leakage was found after secondary lining, water leakage was cut and cut off by caulking, etc., but it was not a measure to directly stop water leakage from the prevention sheet. It was difficult to water.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram for inspecting a buried pipe for water leakage.

FIG. 2 is an enlarged view of a buried pipe.

FIG. 3 is a potential distribution diagram in a case where there is no break in the waterproof sheet.

FIG. 4 is a potential distribution diagram when there is a break in the waterproof sheet.

FIG. 5 is an explanatory view of a leakage inspection during excavation by a shield machine.

FIG. 6 is a sectional view in the direction perpendicular to the axis of the segment.

FIG. 7 is an explanatory view in which metal at a grout inlet is used for an electrode.

FIG. 8 is an explanatory view of arranging electrodes using a grout inlet;

FIG. 9 is an explanatory view of a water leakage inspection during excavation by another shield machine.

FIG. 10 is a layout view of electrodes on the outer periphery of a shield machine.

FIG. 11 is an axial sectional view of a segment.

Claims (7)

[Claims] An apparatus for electrically inspecting a waterproof material covering a buried pipe for water leakage, comprising: an external current electrode disposed outside the waterproof material; an internal current electrode disposed on the buried pipe; A voltage applying means for applying a voltage between the current electrodes; and a measuring electrode for measuring a potential in the vicinity of the surface of the waterproof material. The waterproof material leaks due to a distortion of a potential distribution on the surface of the waterproof material measured by the measuring electrode. A device for inspecting buried pipes for leakage, characterized by determining the position. 2. The apparatus for inspecting a buried pipe for leaks according to claim 1, wherein the internal current electrode uses a reinforcing bar of the buried pipe. 3. The apparatus for inspecting a buried pipe for leakage according to claim 1, wherein a shield machine body is used as an external current electrode. 4. The apparatus for inspecting a buried pipe for leakage according to claim 1, wherein the measuring electrode is disposed in a grout injection hole of the buried pipe. 5. The apparatus for inspecting water leakage of a buried pipe according to claim 1, wherein the external current electrode is disposed on the outer wall surface of the buried pipe insulated from the buried pipe via an insulator. Characteristic device for inspecting leaks in buried pipes. 6. The apparatus for inspecting a buried pipe for leakage according to claim 1, wherein the external current electrode is arranged on an outer periphery of the shield machine. 7. The apparatus for inspecting a buried pipe for leakage according to claim 1, wherein the measuring electrode is arranged on an outer periphery of the segment.