JP2003090753A - Underground water level-detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily detect the behavior of the underground water in an arbitrary stratum with an electrode type water level sensor by an electric cable. SOLUTION: The underground water level-detecting apparatus is provided with a water level sensor and a switcher 8. The water level sensor exposes conductive sections 2a', 2b', and the like to a plurality of electric cables 1a, 1b, and the like where the surface of conductors 2a, 2b, and the like is covered with insulators 3a, 3b, and the like by removing insulators at a predetermined site in each axial direction, arranges the electric cables at an equal interval with a filament common electrode 4 as a center, and is buried into the ground by bundling them in one piece. The switcher 8 is installed on the ground, and successively switches the connection between the common electrode 4 of the water level sensor and the conductors 2a, 2b, and the like of each of the electric cables 1a, 1b, and the like to obtain electric output. The electric resistance between the conductive section of the electric cable and the common electrode is measured from the electric output obtained by the switcher 8, and the water level in the ground is detected based on the position of the conductive section of the electric cable concerned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground water level detecting device for measuring the water level in the ground.

[0002]

2. Description of the Related Art Conventionally, as a means for measuring the water level in the ground, a method of excavating the ground with a boring device and measuring the water accumulated in the excavated boring hole with a float is generally used.

FIG. 7 is a block diagram showing an example of such a conventional float type water level gauge.

In FIG. 7, reference numeral 21 is a foundation concrete that has been driven into the ground.
There is a through hole that runs from the ground surface to the ground. In addition, 22 is a cylinder body that is buried in the ground through the through hole of the basic concrete 21, and this cylinder body 22 is a structure in which a plurality of cylinder parts having appropriate lengths are connected according to the depth of burial in the ground, A plurality of holes penetrating inside and outside the cylinder are provided along the axial direction.

Reference numeral 23 is a case installed on the concrete foundation 21 with the tubular body 22 in the center, and a float drive device 24 is installed in the upper part of the case 23. The float drive device 24 supports a wire 26 having a float 25 attached to the tip thereof so as to be vertically movable through the inside of the tubular body 22, and the float 25 moves up and down according to the water level accumulated in the lower portion of the tubular body 22. By
The wire 26 is wound up or wound down.

Further, in the lower part of the case 23, the water level accumulated at the bottom of the cylindrical body 22 is measured by a moving amount of the wire 26 that is wound up or down by the float drive device 24, and this measuring device 27. A transmitter 29 for transmitting the data measured at 27 to an unillustrated base station through an output cable 28 buried in the ground is installed.

In the underground water level detecting device having such a structure, when rainwater or the like that has fallen to the ground surface due to rainfall penetrates into the ground, this water passes through holes provided along the axial direction of the cylindrical body 22. It collects at the bottom of the cylinder 22. The water level accumulated at the bottom of the cylindrical body 22 is measured by the measuring device 27 from the amount of movement of the wire 26 that is wound up or down according to the vertical movement of the float 25.

However, in such a float type water level gauge, although it is possible to measure the total amount of water accumulated at the bottom of the hole in the boring, how much groundwater is spouting from which part of the formation Could not be identified.

On the other hand, a pore water pressure gauge has been devised to grasp the behavior of groundwater in a specific stratum, and a method of measuring the water pressure of groundwater stored in a particular stratum with a pressure gauge has also been devised and put into practical use. There is.

However, the former pore water pressure gauge has a problem that if there is a crack in the ground to be measured, the water pressure escapes from the crack and the water pressure cannot be measured accurately, and in the latter water pressure gauge, the water pressure gauge is installed. It is necessary to seal the upper and lower parts of the stratum to be constructed so that the pressure does not escape, so special technology is required to install the water pressure gauge,
There was a problem that it could not be installed easily.

[0011]

As described above, the conventional float water level meter cannot determine from which part of the stratum and how much groundwater is springing out, and the pore water pressure gauge cannot measure the groundwater level. The amount of discharge can be measured as water pressure, but the measurement range is limited, and it was not possible to measure the behavior of groundwater at any position in the formation.

It is an object of the present invention to solve the above problems and to provide an underground water level detecting device capable of simply detecting the behavior of groundwater in an arbitrary formation by an electrode type water level sensor using an electric cable. To do.

[0013]

In order to achieve the above object, the present invention constitutes an underground water level detecting device by the following means.

According to the first aspect of the present invention, the conductive portion is removed by removing the insulator at a predetermined axial portion of each of the plurality of electric cables in which the surface of the conductor is covered with the insulator. A water level sensor that is exposed and arranged at equal intervals around the common electrode of the wire and bundled together to be buried in the ground, and a water level sensor installed on the ground and common to the water level sensor. A switching means for sequentially switching the connection between the electrodes and the conductors of the respective electric cables to obtain an electric output. From the electric output obtained by the switching means, the electric resistance between the conductive portion of the electric cable and the common electrode is obtained. Measure and detect the water level in the ground based on the position of the conductive part of the corresponding electric cable.

According to a second aspect of the present invention, in the underground water level detecting device according to the first aspect of the present invention, the conductive portion of the electric cable exposed by the removal of the insulating material is at regular intervals with respect to each electric cable. It is provided by shifting.

According to a third aspect of the present invention, in the underground water level detecting device according to the first aspect of the invention, the water level sensor has a common electrode inserted in the center of a core material made of a porous material or a permeable material. Then, a plurality of electric cables are arranged on the outer peripheral surface of the core material along the axial direction.

According to a fourth aspect of the present invention, in the underground water level detecting device according to the first aspect of the present invention, a plurality of water level sensors are provided on the outer circumference of a cylindrical core member made of a flexible conductor. The electric cable of is arranged along the axial direction.

According to a fifth aspect of the present invention, in the underground water level detecting device according to the fourth aspect of the invention, the core member is provided with a brim portion on the outer peripheral surface thereof at every one low interval.

The invention corresponding to claim 6 is to remove the insulators at a plurality of predetermined locations in the axial direction from a plurality of electric cables each having a conductor surface covered with an insulator. The conductive parts are exposed and the conductive parts of each of these parts are formed as electrodes on a group-by-group basis, which are displaced from each other at a constant interval between the electric cables, and the same number of groups is provided corresponding to the electrodes of each group. The electric cables are arranged at equal intervals centering on the common electrode of the wire and the water level sensor is buried in the ground by bundling them together and is installed on the ground and corresponds to each group of the water level sensors. Switching means for sequentially switching the connection between the common electrode and the conductor of each of the electric cables to obtain an electric output, and the conductive portion of the electric cable and the common electrode from the electric output obtained by the switching means. By measuring the electrical resistance between, based on the position of the conductive portion of the corresponding electrical cables for detecting the water level in the ground.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 respectively show a first embodiment of an underground water level detecting device according to the present invention. FIG. 1 is a plan development view and FIG. 2 is a transverse sectional view.

In FIG. 1, 1a, 1b, ... Are conductors 2
a, 2b, ... Insulators 3a, 3b such as vinyl on the surface
With a plurality of electric cables covered with ..., each of these electric cables 1a, 1b, ... has a conductive portion obtained by removing the insulators 3a, 3b, ... at one predetermined location in the axial direction. 2a ', 2b', ... Are exposed. In this case, the conductive portions 2a ′, 2b ′, ... Have a constant length L,
In addition, the electrodes are formed as electrodes that are displaced from each other at regular intervals with respect to the electric cables 1a, 1b, ....

Reference numeral 4 denotes a wire common electrode, and the common electrode 4 is used as a common electrode for the conductive portions 2a ', 2b', ... Of the electric cables 1a, 1b ,.

The electric cables 1a, 1b, ... And the common electrode 4 are arranged as shown in FIG. That is, the common electrode 4 is inserted into the center hole of the core material 5 made of a cylindrical porous material or permeable material, and the electric cables 1a, 1b, ... Are arranged on the outer peripheral surface of the core material 5 along the axial direction. The water level sensor is constructed by bundling them together.

The electric cables 1a, 1b,
, And the water level sensor configured by bundling the common electrodes 4 integrally are buried in a boring hole formed by excavating the ground by a boring device (not shown).

On the other hand, 6 is a terminal of the measuring instrument which is installed on the ground 7 side and to which the above-mentioned electric cables 1a to 1d and the common electrode 4 are electrically connected.

As shown in FIG. 3, this terminal 6 is provided with a switcher 8, which has a movable contact 8s to which a common electrode 4 and a DC power source 17 are connected and a fixed contact 8s.
The conductors 2 of the electric cables 1a, 1b, ...
, a, 2b, ... Are connected and the output is detected by the resistance meters 18a, 18b ,.
The electric resistance is measured by giving the detected value to a measuring device (not shown).

In the underground water level detecting device having such a structure, assuming that the permeated water in the ground has permeated into the range X as shown by the broken line in FIG. 1, the electric cable 1a,
When water permeates into the conductive portion 2d ′ of the electric cable 1d among the electric cables 1b, ...
The conductive portion 2d 'and the common electrode 4 become conductive, and the resistance value of the electric cable 1d changes. This change in resistance value is electrically measured by a measuring device (not shown) via the terminal 6.

Therefore, the conductive portion 2 of the electric cable 1d
If you decide in advance where d'is from the surface of the earth,
It is possible to specify the depth in the ground where the seepage water exists.

As described above, in the present embodiment, a plurality of electric cables 1a, each of which has a conductive portion exposed by removing the insulator at one predetermined position at different axial positions, respectively. .. and the common electrode 4 are buried in the ground, and the permeated water in the ground contacts the conductive portions 2a ', 2b' ,. Therefore, it is not necessary to newly provide a special electrode for detecting the water level or to pass a wire for detecting the water level in the pipe, and the water level in the ground can be easily measured.

Further, the common electrode 4 is inserted into the center hole of a core material 5 made of a cylindrical porous material or a permeable material, and the electric cables 1a, 1b, ... Since the water level sensor is constructed by bundling them together and forming a water level sensor, they are also good against electric contact and can be easily buried by using the boring holes excavated for testing as they are. can do.

FIG. 4 is a perspective view showing a second embodiment of the underground water level detecting device according to the present invention.

In FIG. 4, reference numeral 11 denotes a cylindrical core material having conductivity, and a plurality of electric cables 14 each having an outer peripheral surface of the core material 11 and a surface of a conductor 12 covered with an insulator 13 are arranged in an axial direction. Are respectively arranged along the line. In this case, the electric cables 14 are arranged at intervals such that a slight gap exists between them, so that the permeated water can also contact the core material 11.

In each of these electric cables 14, the insulator 13 at a predetermined portion in the axial direction is removed from each of the electric cables 14, and a constant pitch L is given to this portion as shown by hatching.
The conductive portions 12a of are exposed and formed as electrodes of the water level sensor at different axial positions.

Here, the conductive core material 11 is
For example, aluminum or a stainless steel pipe is processed into a wavy shape so as to have flexibility, and also serves as a common electrode.

The electric cable 14 integrated with the core member 11 thus constructed is embedded in each boring hole formed by excavating the ground by a boring device (not shown), and a measuring instrument (not shown) installed on the ground side. The electrical resistance is measured by electrically connecting to the terminal of the terminal and supplying the output to the measuring instrument while sequentially switching the connection end of each electric cable with the switching instrument provided in the terminal.

Even with the underground water level detecting device having such a structure, it is possible to obtain the same operational effect as that of the first embodiment, and of course, it is possible to easily carry out the handling and the work when it is buried in the ground. it can. That is, in general, electric cables are
Since it is easily bent and has a low tensile strength, it requires a lot of labor and time to handle it and bury it in the ground.

In this embodiment, since the electric cable 14 is integrally arranged with the core member 11 as the core portion,
An underground water level gauge with excellent flexibility can be provided. Also,
When it is buried in the ground, it can be installed even if the boring hole excavated for burying is slightly bent, and it is not necessary to dig a hole with a strict straightness, so the installation work can be simplified.

FIG. 5 is a sectional view showing a third embodiment of the underground water level detecting device according to the present invention. The same parts as those in FIG.

In the third embodiment, as shown in FIG. 5, a conductive core material 11 in which tapered collar portions 11a are formed at a constant interval C is used, and a conductor is provided on the outer peripheral surface of the core material 11. A plurality of electric cables 14 each having a surface of 12 covered with an insulator 13 are arranged along the axial direction.
In this case, the electric cable 14 includes the collar portion 11 a of the core material 11.
The outer edge and the straight part are adhered with an adhesive or the like.

Further, in these electric cables 14, a part of the insulator 13 between the flange portions 11a which is predetermined for each of them is removed, and conductive portions 12a having a constant pitch are provided in this portion as shown by hatching. It is exposed and formed as an electrode of a water level sensor. In this case, the conductive portion 12a of each electric cable 14 is formed as an electrode at a position different in the axial direction.

In embedding the electric cable 14 integrated with the core material 11 thus constructed in the boring hole formed by excavating the ground 15 by a boring device (not shown), the boring hole and the electric cable 14 are buried. The grouting material 16 such as sand is filled with honey in the gap between the surroundings of the honey.

Since the other structure is the same as that of FIG. 4, its explanation is omitted here.

Even in the third embodiment having such a structure, the same effects as those of the second embodiment can be obtained, and since the brim portion 11a is formed in the core material 11, the conductive property is obtained. It is possible to prevent the groundwater stored in the portion 12a from flowing down to the lower portion in a short time as it is, and it becomes easy to detect the accurate groundwater position.

FIG. 6 is a block diagram showing a fourth embodiment of an underground water level detecting device according to the present invention. The same parts as those in FIG.

In FIG. 6, 1a, 1b, ... Are conductors 2
, a plurality of electric cables whose surfaces are covered with insulators 3a, 3b ,.
a, 1b, ... At the respective different positions in the axial direction and by removing the insulators 3a, 3b, ... at two predetermined locations, the first conductive portions 2a ′, 2b ′ ,. The second conductive portions 2a ″, 2b ″, ... Are exposed. In this case, the first conductive portion 2a ′, 2b ′, ... And the second conductive portion 2
The electrodes a ″, 2b ″, ... Have a constant length L, and are formed as group-unit electrodes that are displaced from the electric cables 1a, 1b ,.

Further, 4a and 4b are a first common electrode and a second common electrode corresponding to the conductive portions of each group,
The first common electrode 4a is the above-mentioned electric cables 1a, 1
The second common electrode 4b is used as a common electrode for the first conductive parts 2a ', 2b', ... Of the b, ..., And the second common electrode 4b is the second conductive part 2a 'of each of the electric cables 1a, 1b ,. ',
2b ″, ... Used as a common electrode.

The electric cables 1a, 1b, ... And the first and second common electrodes 4a, 4b are in the state of being electrically insulated from each other, and in the same manner as in FIG. Is coaxially inserted into the central hole of the core material, and the electric cables 1a, 1b, ... Are arranged along the axial direction on the outer peripheral surface of the core material, and these are bundled together to form a water level sensor. . The upper portion 4b 'of the common electrode 4b is the conductive portion 2
, 2a 'and 2d'', ..., 2a''are covered with an insulating coating in order to prevent electrical interference between the common electrodes 4a.

On the other hand, the terminal 6 installed on the ground 7 side
The switch 8 included in the electrode switching fixed contacts 8p1 and 8p2 is connected to the movable contact 8s1 and the electrode switching movable contact 8s2, and the first common electrode 4a and the second common electrode 4b that are common lines. , Fixed contacts 8a, 8b, to which the conductors 2a, 2b, ... Of the electric cables 1a, 1b ,.
…have.

In such a switching device 8, the movable contacts 8s1 are sequentially switched while the electrode switching movable contact 8s2 is connected to the electrode switching fixed contact 8p1 so that the first electric cables 1a, 1b ,. Conductive parts 2a ', 2b',
The electric resistance can be detected by ... And the movable contact 8s1 is sequentially switched in a state where the electrode switching movable contact 8s2 is connected to the electrode switching fixed contact 8p2, whereby the second electric cables 1a, 1b ,. Conductive part 2a '', 2
The electric resistance can be detected by b ″, ....

With the underground water level detecting device having such a structure, it is possible to obtain the same effects as those of the first embodiment, and, of course, it is possible to reach deep into the ground without increasing the number of electric cables. The water level can be measured.

Incidentally, in the case where the insulator is cut at two predetermined axial positions for one electric cable to expose the conductive portion as in the fourth embodiment, one electric cable is exposed. It is possible to detect the water level up to twice the depth of the ground as compared with the case where the conductive portion is exposed.

In the above-mentioned embodiment, the case where two predetermined insulators in the axial direction are cut on one electric cable to expose the conductive portion has been described. However, the conductive portions may be exposed at three or more predetermined axial positions.

In each of the above-described embodiments, the electric cable has the surface of the conductor covered with an insulator such as vinyl, but the surface of the conductor is coated with an insulating coating to form an insulating layer. Electric cables may be used. By using such an electric cable, the conductor portion can be exposed by a simple operation of peeling off the insulating layer.

[0055]

As described above, according to the present invention, it is possible to provide an underground water level detecting device capable of easily detecting the behavior of groundwater in an arbitrary formation by an electrode type water level sensor using an electric cable.

[Brief description of drawings]

FIG. 1 is a development view showing a first embodiment of an underground water level detecting device according to the present invention in plan view.

FIG. 2 is a cross-sectional view showing the same embodiment.

FIG. 3 is a configuration diagram showing a connection between a water level sensor and a terminal according to the same embodiment.

FIG. 4 is a perspective view showing a second embodiment of an underground water level detecting device according to the present invention.

FIG. 5 is a sectional view showing a third embodiment of the underground water level detecting device according to the present invention.

FIG. 6 is a configuration diagram showing a wire connection between a water level sensor and a terminal in a fourth embodiment of an underground water level detecting device according to the present invention.

FIG. 7 is a configuration diagram showing an example of a conventional underground water level detection device.

[Explanation of symbols]

, 14: electric cables 2a, 2b, ..., 12: conductors 2a ', 2b', ..., 2a '', 2b '', ..., 12
a: Conductive parts 3a, 3b, ..., 13: Insulators 4, 4a, 4b: Common electrode 4b ': Common electrode coating insulating part 5, 11: Core material 6: Terminals 7, 15: Ground 8: Switch 11a: Collar 16: Grouting material 17: DC power supplies 18a, 18b, ...: Resistance meter

Claims (6)

[Claims] 1. An electric cable for a plurality of electric cables, the surface of a conductor of which is coated with an insulating material, by removing the insulating material at a predetermined axial position to expose a conductive portion. Are arranged at equal intervals centering on the common electrode of the wire and are integrally bundled and buried in the ground, and the common electrode of the water level sensor installed on the ground and each of the electric cables. Switching means for sequentially switching the connection with the conductor to obtain an electric output, and measuring the electric resistance between the conductive portion of the electric cable and the common electrode from the electric output obtained by the switching means to obtain the corresponding electric power. An underground water level detection device, which detects the underground water level based on the position of a conductive portion of a cable. 2. The underground water level detecting device according to claim 1, wherein the conductive portion of the electric cable exposed by the removal of the insulating material is provided so as to be shifted at regular intervals with respect to each electric cable. Underground water level detection device. 3. The underground water level detecting device according to claim 1, wherein the water level sensor has a common electrode inserted in a central portion of a core material made of a porous material or a permeable material, and a plurality of electrodes are provided on an outer peripheral surface of the core material. An underground water level detecting device comprising a plurality of electric cables arranged along an axial direction. 4. The underground water level detecting device according to claim 1, wherein the water level sensor has a plurality of electric cables arranged along an axial direction on an outer periphery of a cylindrical core member made of a flexible conductor. An underground water level detecting device characterized by being installed. 5. The underground water level detecting device according to claim 4, wherein the core member has a brim portion provided on the outer peripheral surface thereof at every one low interval. 6. For a plurality of electric cables in which the surface of a conductor is covered with an insulating material, the insulating material is removed at a plurality of predetermined locations in the axial direction to expose the conductive portion, The conductive part of each of these parts is formed as an electrode of a group unit that is shifted at a constant interval between the electric cables, and centered on the common electrodes of the same number of lines as the number of groups provided corresponding to the electrodes of each group. A water level sensor in which the electric cables are arranged at equal intervals and are integrally bundled and buried in the ground; a common electrode installed on the ground and corresponding to each group of the water level sensors and the electric cables; Switching means for sequentially switching the connection with the conductor to obtain an electric output, and measuring the electric resistance between the conductive portion of the electric cable and the common electrode from the electric output obtained by the switching means. An underground water level detection device, which detects the underground water level based on the position of the conductive portion of the corresponding electric cable.