JP2010002259A - Water level detection sensor and water level detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a water level detection sensor and a water level detection device that can always maintain constant detection accuracy and can also be used for a long time. <P>SOLUTION: The water level detection device has the water level detection sensor 10 including a sensor mounting body being formed like a rod with a pointed tip and having a window part 11a going through at right angle to the axis direction, and a sensor element 12 disposed on the sensor mounting body so as to cover the opening of the window part 11a and capable of converting electrical energy to mechanical energy. The water level can be detected by sensing the seepage water in a dam body by installing a plurality of the water level detection sensors 10 at the toe of the slope of the dam body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water level detection sensor for detecting the water level of osmotic water and a water level detection device using the water level detection sensor.

  Conventionally, there is a method disclosed in Patent Literature 1 as a method for detecting penetrating moisture in the soil. In the method disclosed in Patent Document 1, a liquid absorber is accommodated in a porous cylinder, and the liquid absorber absorbs moisture with a piezoelectric element attached to the upper part of the cylinder. Is.

JP-A-9-243614

  However, in the method disclosed in the above-mentioned patent gazette, in order to continue to detect the moisture contained in the absorbent body in the cylinder even when the moisture in the soil is reduced, there is a use in which the water level of the river is fluctuating like a bank Not suitable for. Moreover, since a difference in moisture absorption occurs depending on the degree of dirt on the absorber, variations in moisture detection are likely to occur. In addition, if the absorbent body becomes dirty, it needs to be replaced, which is expensive.

  The present invention has been made in view of such circumstances, and can be used for applications where the water level of rivers varies, such as a dam body, and can always maintain a constant detection accuracy, and can be used over a long period of time. It is an object of the present invention to provide a water level detection sensor and a water level detection device that can be used.

The above object of the present invention is achieved by the following configuration.
(1) A water level detection sensor comprising: a sensor element capable of converting electrical energy into mechanical energy; and a sensor mounting body on which the sensor element is mounted such that the detection unit can be exposed, and is embedded in soil. .

(2) The water level detection sensor according to (1), wherein the sensor element is a piezoelectric ceramic.

(3) In the water level detection sensor according to the above (1) or (2), the sensor attachment body is formed in a wedge shape with one end side formed in a rod shape, and penetrates in a direction perpendicular to the axial direction. The sensor element is attached so that the detection portion covers the opening of the window portion.

(4) The water level detection sensor according to (3) above, wherein a net covering the opening is provided in the opening on the side opposite to the sensor of the window.

(5) In the water level detection sensor according to the above (3) or (4), at least one embedment regulating plate protrudes in an orthogonal direction to the axial direction on the outer surface of the sensor attachment body.

(6) In the water level detection sensor according to the above (1) or (2), the sensor attachment body has a mesh portion that exposes at least a detection portion of the sensor element, and is a substantially box that can accommodate the sensor element. It is formed in the body.

(7) In the water level detection sensor according to (1) or (2), the sensor attachment body is formed in a bowl shape having at least a mesh part that exposes a detection part of the sensor element, and the sensor element Is mounted on a saddle-shaped convex surface.

(8) A water level detection device for detecting the level of osmotic water in the levee body, comprising a plurality of water level detection sensors according to (1) to (7) above, and the frequency changing over time within a predetermined range. A signal generating means for generating a sine wave signal, a switching means for switching a plurality of the water level detection sensors one by one and applying a sine wave signal generated by the signal generating means, and each time switching by the switching means is performed. Detecting changes in current flowing through the sensor element of the water level detection sensor to which a sine wave signal has been applied as changes in voltage and detecting changes in the frequency characteristics of the captured voltage waveform to detect infiltrated water in the soil Means for burying a plurality of the water level detection sensors at a plurality of locations in the bottom of the levee body, and detecting the level of permeated water in the bottom of the dam.

(9) The water level detection device according to (8), further comprising a communication unit that is connectable to an electric communication line and transmits water level detection information obtained from the detection unit using the electric communication line. It is characterized by that.

According to the present invention, it can be used for an application where there is a fluctuation in the water level of a river such as a bank body, and can always maintain stable detection accuracy and can be used for a long period of time. In particular, by observing changes in the seepage water in the levee over time, it becomes easier to predict levee breaks and collapses.
That is, the water level detection sensor in which the conventional absorber is omitted can continuously detect moisture while moisture is present in the window portion, and does not detect moisture due to the moisture being discharged from the window portion. Therefore, even in the levee body where fluctuation of moisture in the soil occurs, it is possible to always detect the infiltrated water in the levee body stably.
Moreover, according to the water level detection apparatus provided with the said water level detection sensor, a water level can be detected over a wide range by embedding a plurality of water level detection sensors in a plurality of locations of the bank body.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a water level detection device according to an embodiment of the present invention. The water level detection device of the present embodiment detects the level of permeated water in a river bank, but can be used for any detection of water level in the soil.

  In FIG. 1, the water level detection device 1 of the present embodiment includes a plurality of water level detection sensors 10, a switch 15, a voltage controlled oscillator 20, amplifiers 21 to 23, a resistor 24, a differential amplifier 25, A four-quadrant analog multiplier 26, a low-pass filter 27, a control unit 28, a communication unit 29, and an antenna 30 are configured. The water level detection sensor 10 is embedded in soil in the levee body and detects permeated water.

2A and 2B are perspective views showing the external appearance of the water level detection sensor 10, wherein FIG. 2A is a perspective view seen from the front side, and FIG. 2B is a perspective view seen from the back side.
As shown in this figure, the water level detection sensor 10 is provided with a sensor attachment body 11 having a window portion 11a that allows a detection portion of a sensor, which will be described later, to be exposed, and the sensor attachment body 11, and is made of piezoelectric ceramics or the like. The sensor element 12 can convert electrical energy into mechanical energy. The sensor mounting body 11 is formed in a wedge shape with one end side (hereinafter referred to as a tip portion) of a square pole (or a hollow cylindrical shape) having a sharp point, and a shaft slightly closer to the other end side than the center portion. A window portion 11a penetrating in a direction perpendicular to the direction. The sensor mounting body 11 is mounted with the sensor element 12 having the detection portion disposed so as to cover the opening of the window portion 11a.

  The sensor attachment body 11 has one embedment regulating plate 11b that protrudes in a direction perpendicular to the axial direction at an outer surface position substantially in the middle between the tip portion and the window portion 11a. Moreover, the sensor attachment body 11 is provided with the net | network body 11c in the opening by the side of the non-sensor attachment of the window part 11a so that this opening may be covered. The sensor mounting body 11 is made of a material that is durable and resistant to corrosion, such as plastic.

  The embedding regulation plate 11b regulates the embedding position of the water level detection sensor 10 so that the embedding depth of the sensor mounting body 11 changes with time when the sensor mounting body 11 is embedded in the soil in the levee body. . Note that the embedding restriction plate 11b does not necessarily have to protrude in a direction perpendicular to the axial direction, and may have a slight angle. In short, any attachment method may be used as long as the water level detection sensor 10 is not moved from the embedded position. Further, the number provided is not limited to one, and may be two or three.

The net 11c prevents soil and sand from reaching the detection surface of the water level detection sensor 10 and contaminating them. The size of the mesh is such that fine soil or sand other than moisture enters the window portion 11a. The size is not.
Each sensor element 12 is connected to the switching unit 15 via a cable 11d. The cable 11d is covered with a protective tube 50 (see FIG. 3) for enhancing water resistance and corrosion resistance.

FIG. 3 is a view showing a state in which the water level detection sensor 10 is embedded in the soil in the levee body.
As shown in this figure, the water level detection sensor 10 is inserted into a buried hole having a diameter of 60 to 100 mm with the wedge-shaped tip portion facing downward, and then silica sand 60 is put on the outer peripheral surface thereof, and clay 61 is placed on the upper surface of the sensor. It is buried with. In this way, by inserting the silica sand 60 around the sensor during embedding, sludge, dust, etc. are filtered, making it difficult for water impurities to adhere to the net 11c and the sensor element body, and clogging of the net 11c and sensor detection. It is possible to prevent malfunction of the sensor element 12 due to adhesion of sludge or the like to the surface.

  Further, since the water level detection sensor 10 is sized so that fine soil or sand does not enter the mesh of the mesh body 11c, the silica sand 60 does not enter the window portion 11a. In addition, as shown in FIG. 4, the through-hole which forms the window part 11a makes the surface used as the bottom face 11ab the shape which inclined gradually toward the net | network body 11c side from the sensor element 12 side, and thereby the window part 11a. The water can be well drained inside.

FIG. 5 is a perspective view showing a state in which a plurality of water level detection sensors 10 are installed on the bottom of the bank body 70. 6 is a perspective view (a) showing the embedded state of the plurality of water level detection sensors 10, and a cross-sectional view (b) showing the embedded portion.
The plurality of water level detection sensors 10 are embedded in the slope 70a of the levee body 70 at regular intervals along the longitudinal direction of the slope and in multiple stages (two stages in this example) along the inclination direction.
The cable 11d connected to each water level detection sensor 10 is connected to the switch 15 of the water level detection device 1 installed in the shed 80 on the bank body. As shown in FIG. 6, the embedding hole 70b for embedding each water level detection sensor 10 is provided in a direction perpendicular to the inclined surface of the buttock. 5 and 6, reference numeral 90 indicates a river.

  Returning to FIG. 1, the switch 15 has a large number of semiconductor analog switches (or mechanical relay contacts), and performs switching according to a switching signal from the control unit 28. A plurality of water level detection sensors 10 are connected to the switch 15, and the plurality of water level detection sensors 10 are sequentially switched by sequentially turning on / off the semiconductor analog switch (or mechanical relay contact).

The voltage controlled oscillator 20 generates a sinusoidal electric signal whose frequency continuously changes in a predetermined frequency range (for example, 1 kHz to 20 kHz). The amplifier 21 amplifies the sine wave signal generated by the voltage controlled oscillator 20 to a level at which the sensor element 12 of the water level detection sensor 10 can be driven, and outputs the signal as an excitation signal Vr.
The resistor 24 is inserted in series between the amplifier 21 and the water level detection sensor 10, and a voltage corresponding to the current flowing through the sensor element 12 of the water level detection sensor 10 is generated at both ends thereof.
Since the current flowing through the sensor element 12 of the water level detection sensor 10 changes according to the change in frequency, the voltage appearing across the resistor 24 reflects the frequency characteristics of the sensor element 12.

  The differential amplifier 25 amplifies the voltage generated at both ends of the resistor 24 and outputs the amplified voltage. The amplifier 22 amplifies the voltage output from the differential amplifier 25 to a predetermined level and outputs it as a voltage Vi. The 4-quadrant analog multiplier 26 multiplies the excitation signal Vr from the amplifier 21 and the output voltage Vi from the amplifier 22 to remove the influence of noise on these voltages.

  The low-pass filter 27 outputs a signal obtained by removing cos (2ωt + α + β), which will be described later, from the output signal of the 4-quadrant analog multiplier 26. The amplifier 23 amplifies the signal that has passed through the low-pass filter 27 to a predetermined level and outputs it as an output signal Vo. The output voltage Vo is a signal reflecting the frequency characteristics of the sensor element 12 with respect to the frequency change of the excitation signal Vr. At this time, if nothing is in contact with the surface of the sensor element 12, that is, if the surrounding is air, the frequency near the natural frequency of the sensor element 12 as shown in the output voltage waveform diagram of FIG. A voltage with a peak appears. When water contacts the surface of the sensor element 12 from this state, the vibration characteristics of the sensor element 12 change, and the peak voltage position has a lower frequency as shown in the output voltage waveform diagram of FIG. And the amplitude becomes smaller. The contact / non-contact of water can be determined from the change in peak voltage.

  Here, the operation principle will be described using mathematical expressions as follows. Note that Vr = Asin (ωt + α) and Vi = Bsin (ωt + β). However, A and B are amplitudes, ωt is a frequency, and α and β are phase shifts.

Vr × Vi = Asin (ωt + α) × Bsin (ωt + β)
= AB [cos (β-α) -cos (2ωt + α + β)] / 2 (1)

  The cos (β−α) portion of the equation (1) is a direct current component that changes in accordance with the phase difference, and includes the amplitude component of the signal Vi. The portion of cos (2ωt + α + β) is a signal having a frequency twice that of the original excitation signal Vr and the signal Vi. Since the required frequency characteristic information is the amplitude (magnitude) of the signal Vi, only cos (β−α) in equation (1) is sufficient. Therefore, the component of cos (2ωt + α + β) may be removed by passing through the low-pass filter 27. In this way, the frequency characteristic appears in the form of voltage in the output Vo. When water penetrates into the window portion 11a of the water level detection sensor 10, the situation can be detected by changing the peak frequency and level.

  Returning to FIG. 1, the control unit 28 includes a CPU (not shown), a ROM storing a program for controlling the CPU, a RAM used in the operation of the CPU, an interface for inputting and outputting signals, and the like. The switch 15 is controlled so that the water level is detected by each of the plurality of water level detection sensors 10, and each detection result is transmitted from the communication unit 29. That is, the control unit 28 controls the switch 15 to sequentially switch the plurality of water level detection sensors 10, and determines contact / non-contact of water from the output signal Vo of the amplifier 23 for each water level detection sensor 10, and as a result. Is input to the communication unit 29 as water level detection information. Determination of contact / non-contact of water is based on a characteristic vibration frequency characteristic when water does not contact the sensor element 12 of the water level detection sensor 10 (that is, when the surrounding is air). Note that once the unique vibration frequency characteristic of the sensor element 12 is set, it is not necessary to reset it except during maintenance.

  The communication unit 29 performs communication using a public line network, and converts water level detection information input from the control unit 28 into a radio signal in a frequency band and radio wave format used for data communication of the public line network. Then send.

  FIG. 10 is a diagram illustrating a communication path between the water level detection device 1 and a user terminal (so-called personal computer) 100. The water level detection device 1 and the user terminal 100 are connected via a public network 110. The public line network 110 includes a data communication unit 120, a data management unit 130, and an Internet information providing unit 140 owned by a communication carrier. The data communication unit 120 and the data management unit 130 are connected by a dedicated line 150. Routers 120 a and 130 a are arranged at both ends of the dedicated line 150 connecting the data communication unit 120 and the data management unit 130.

  The data communication unit 120 receives the radio signal transmitted from the water level detection device 1, demodulates the water level detection information, and transmits it to the data management unit 130. The data management unit 130 includes a router 130a and a center monitoring device 130b. The center monitoring device 130b converts the water level detection information sent from the data communication unit 120 into HTML (HyperText Markup Language) format to the Internet information providing unit 140. Send.

  The internet information providing unit 140 includes a router 140a and a web server 140b. The web server 140b accumulates HTML level water level detection information transmitted from the center monitoring apparatus 130b, and is sent from a web browser installed in the user terminal 100. In response to the request, it is provided to the user terminal 100 using a content transmission / reception protocol such as HTTP (Hypertext Transfer Protocol). It is also possible to use an intranet other than the Internet.

  The voltage controlled oscillator 20 and the amplifier 21 constitute signal generating means. The switch 11 and the control unit 28 constitute a switching unit. The resistor 24, the amplifiers 22 and 23, the differential amplifier 25, the four-quadrant analog multiplier 26, the low-pass filter 27, and the control unit 28 constitute detection means. Further, the communication unit 29 and the antenna 30 constitute a communication unit. The user terminal 100 corresponds to a monitoring device.

  In the water level detection device 1 configured as described above, a water level detection in which a sine wave signal generated by the voltage controlled oscillator 20 is amplified by the amplifier 21 and is switched and connected to the device main body by the switching unit 15 as the excitation voltage Vr. It is input to the sensor element 12 of the sensor 10 and the 4-quadrant analog multiplier 26. When the vibration signal Vr is input to the sensor element 12 of the water level detection sensor 10, mechanical vibration is generated from the sensor element 12. In addition, a voltage corresponding to the current flowing through the sensor element 12 is generated at both ends of the resistor 24. After the voltage is amplified by the differential amplifier 25, it is further amplified by the amplifier 22 to output the voltage Vi. The voltage Vi from the amplifier 22 and the excitation signal Vr from the amplifier 21 are multiplied by the four-quadrant analog multiplier 26, and the cos (2ωt + α + β) component is removed from the output by the low-pass filter 27. The output voltage Vo is obtained by being amplified by the signal 23.

  The output signal Vo is a signal reflecting the frequency characteristics of the sensor element 12 with respect to the frequency change of the excitation signal Vr. If nothing is in contact with the surface of the sensor element 12 at this time, a voltage having a peak at a frequency near the natural frequency of the sensor element 12 appears as shown in the output voltage waveform diagram of FIG. When water contacts the sensor element 12, the vibration characteristic of the sensor element 12 changes, and the position and magnitude of the peak voltage change as shown in the output voltage waveform diagram of FIG. The control unit 28 determines contact / non-contact of water from the change in the peak voltage, converts the result into a data format that can be handled by the communication unit 29, and transmits the result to the public line network 110 from the communication unit 29. The control unit 28 performs this process for each of the plurality of water level detection sensors 10. Thereby, in the user terminal 100, it is known whether or not there is a water level at least up to the position of the water level detection sensor 10 currently selected. Since the control unit 28 performs control to repeatedly switch the plurality of water level detection sensors 10 one by one, it is possible to detect the diffusion of the permeated water over a wide range of the slope 70a of the levee body 70.

  Thus, according to the water level detection device 1 of the present embodiment, the tip portion is formed in a rod-like shape, and the window portion 11a has a window portion 11a penetrating in a direction perpendicular to the axial direction in a portion other than the tip portion. The sensor mounting body 11 has an embedment regulating plate 11b projecting to a portion below 11a, and the sensor element 12 is provided in the window portion 11a of the sensor mounting body 11 and can convert electrical energy into mechanical energy. The water level detection sensor 10 is provided. And this water level detection sensor 10 can detect it while water exists in the window part 11a, and since it stops detecting by discharging | emitting from the window part 11a, the permeated water in a levee body is improved. At the same time that the water level can be detected, the water level can be detected from the plurality of water level detection sensors 10. Moreover, since this water level detection sensor 10 does not have a conventional absorber, there is no variation in moisture detection, and the permeated water can be detected stably. Furthermore, since the cost required for replacement does not occur due to the absence of the absorber, the cost can be kept low. Moreover, since the depth embedded by the burying control board 11b is maintained, a water level can be detected correctly over a long period of time. In addition, by using piezoelectric ceramics as the sensor element 12, the water level detection sensor 10 can be made inexpensive and highly accurate detection is possible. In particular, it is not necessary to open a buried hole for detecting penetrating water in large-scale bowling work as in the past, and it can be a relatively shallow hole dug with tools such as hand digging and auger. The burial work is simplified and a wide range of measurements can be made at low cost.

  In addition, the water level detection device 1 can be connected to the public line network and includes the communication unit 29 that transmits the water level detection information using the public line network. Can be monitored.

FIG. 8A is a perspective view of an exploded state of a water level detection sensor 10A according to another embodiment of the present invention, and FIG. 8B shows a state where the water level detection sensor 10A is embedded in the soil.
As shown in FIG. 8A, the water level detection sensor 10 </ b> A includes a sensor attachment body 81 formed in a substantially box body that can accommodate the sensor element 12 by a mesh body, and is accommodated and fixed in the sensor attachment body 81. The sensor element 12 is equipped. The sensor mounting body 81 has such a size that the mesh body covers the detection portion 12a of the sensor element 12 and does not become an obstacle to water permeation, and the particle size of the silica sand 60 disposed around when the sensor mounting body 81 is buried in the soil. Even fine mesh is formed. In the present invention, such a mesh body is referred to as having a mesh portion that allows the detection unit 12a to be exposed. Therefore, in the above-described embodiment, the sensor mounting body 81 is entirely formed of a mesh body. However, at least a box body having a mesh portion only on the surface facing the detection portion 12a of the sensor may be used. In this case, the sensor mounting body is required to have a structure in which the rising water level is immediately brought into contact with the detection unit, and the drainage in the box is improved as the water level decreases.
The sensor mounting body 81 is preferably resistant to corrosion and has a desired mechanical strength. For example, a material such as synthetic resin or stainless steel can be applied.

The water level detection sensor 10A, as shown in FIG. 8 (b), is inserted into a buried hole dug in the soil, and then puts silica sand 60 in the outer periphery to prevent direct inflow of rain into the buried hole. Therefore, the clay 61 is placed on the sensor and buried.
When the permeated water in the soil is saturated and the water level rises to the detection unit 12a of the sensor element 12, the water level is detected by the change in frequency of the current flowing through the detection unit 12a.

FIG. 9A is a perspective view of a disassembled state of a water level detection sensor 10B according to still another embodiment of the present invention, and FIG. 9B shows a state in which the water level detection sensor 10B is embedded in the soil.
As shown in FIG. 9A, the water level detection sensor 10 </ b> B includes a sensor attachment body 91 that is formed in a bowl shape so that the sensor element 12 can be attached, and the sensor element 12 that is attached to the sensor attachment body 91. Consists of The sensor mounting body 81 includes a mounting portion 94 that positions and fixes the sensor element 12 at a substantially central portion of the bowl-shaped convex surface. The attachment portion 94 is formed in a rectangular shape by a peripheral wall that surrounds the outer peripheral portion of the sensor element 12, and a locking claw 98 that can fix the sensor element 12 with one touch is formed on a part of the pair of opposing peripheral walls. When the sensor element 12 is pushed into the mounting portion 94, the locking claw 98 is elastically deformed and engages with the sensor element 12 to fix the sensor element 12 so that it cannot be dropped off.

  At the bottom of the attachment portion 94, there is a mesh portion 96 that allows the detection portion 12a (see FIG. 8) of the sensor element 12 to be exposed on the concave surface side of the bowl shape. When the water level detection sensor 10B is embedded in the soil, the mesh part 96 is formed in a mesh finer than the grain size of the silica sand 60 disposed around. The sensor attachment body 91 is integrally formed including the mesh part 96.

The sensor mounting body 91 configured in this way is inserted into the buried hole in the soil with the cover covered. The sensor mounting body 91 is provided with a plurality of drain holes 92 at appropriate positions so that the sensor attachment body 91 will not be lifted by the rising water level when the permeated water level rises.
The sensor attachment 91 is preferably resistant to corrosion and has a desired mechanical strength. For example, a material such as synthetic resin or stainless steel can be applied.

As shown in FIG. 9B, the water level detection sensor 10B is inserted into a buried hole dug in the soil, and then buried with quartz sand 60 in the outer periphery thereof. In this water level detection sensor 10B, since the sensor mounting body 91 is bowl-shaped, it is difficult to be affected by rain entering from above, so that it is not necessary to put clay on the sensor as in the previous embodiment. Absent.
When the permeated water in the soil is saturated and the water level rises to the detection unit 12a of the sensor element 12, the water level is detected by the change in frequency of the current flowing through the detection unit 12a.

It is a block diagram which shows schematic structure of the water level detection apparatus which concerns on one embodiment of this invention. The external appearance of the water level detection sensor applied to the water level detection apparatus of FIG. 1 is shown, (a) is the perspective view seen from the front side, (b) is the perspective view seen from the back side. It is a figure which shows the embedding state of a water level detection sensor. It is sectional drawing which shows the example of a change of a water level detection sensor. It is a block diagram of the water level detection apparatus which shows a mode that the some water level detection sensor was installed in the slope of a levee body. They are the perspective view (a) which shows the embedding state of a some water level detection sensor, and sectional drawing (b) which shows an embedding part. It is a wave form diagram of output voltage Vo in a water level detection sensor, (a) is a wave form diagram which detected air, and (b) is a wave form diagram which detected water. The water level detection sensor which concerns on other embodiment of this invention is shown, (a) is a perspective view of a decomposition | disassembly state, (b) is a figure which shows the embedding state of a water level detection sensor. The water level detection sensor which concerns on other embodiment of this invention is shown, (a) is a perspective view of a decomposition | disassembly state, (b) is a figure which shows the embedding state of a water level detection sensor. It is a figure which shows the communication path | route between a water level detection apparatus and a user terminal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water level detection apparatus 10, 10A, 10B Water level detection sensor 11 Sensor mounting body 11a Window part 11b Buried control board 11c Net body 11d Cable 12 Sensor element 15 Switcher 70 Dyke body 70a Leg bottom 81 Sensor mounting body 90 River 91 Sensor mounting body 100 User terminal 110 Public line network

Claims (9)

A sensor element capable of converting electrical energy into mechanical energy;
A sensor mounting body on which the sensor element is mounted so as to expose the detection unit;
A water level detection sensor characterized by being embedded in the soil.   The water level detection sensor according to claim 1, wherein the sensor element is a piezoelectric ceramic.   The sensor mounting body is formed in a wedge shape with one end side formed in a rod shape and has a window portion penetrating in a direction perpendicular to the axial direction, and the sensor element has a detection portion covering an opening of the window portion. The water level detection sensor according to claim 1, wherein the water level detection sensor is attached to the water level detection sensor.   The water level detection sensor according to claim 3, wherein a net body that covers the opening is provided at an opening of the window portion on the side opposite to the sensor.   5. The water level detection sensor according to claim 3, wherein at least one buried regulating plate protrudes in an orthogonal direction to the axial direction on an outer surface of the sensor mounting body.   3. The water level according to claim 1, wherein the sensor attachment body has a mesh portion that exposes at least a detection portion of the sensor element, and is formed in a substantially box body that can accommodate the sensor element. Detection sensor.   The sensor mounting body is formed in a bowl shape having at least a mesh part that exposes a detection part of the sensor element, and the sensor element is mounted on a bowl-shaped convex surface. Or the water level detection sensor of 2. A water level detection device for detecting the level of osmotic water in a levee body,
A plurality of the water level detection sensors according to claim 1, and a signal generation unit that generates a sine wave signal whose frequency changes with time in a predetermined range and a plurality of the water level detection sensors are switched one by one. The switching means for applying the sine wave signal generated by the signal generating means, and the change in current flowing through the sensor element of the water level detection sensor to which the sine wave signal is applied every time switching by the switching means is performed. And detecting means for detecting the infiltrated water in the soil by detecting changes in the frequency characteristics of the captured voltage waveform, and embedding a plurality of the water level detection sensors at a plurality of locations within the heel of the levee body And the water level detection apparatus which detects the water level of the osmosis | permeation water in the said method bottom.   9. The water level detection device according to claim 8, further comprising a communication unit that is connectable to an electric communication line and transmits water level detection information obtained from the detection unit using the electric communication line.

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