JP2020106273A - Deflection measuring device using pipe - Google Patents

Abstract

To provide a deflection measuring device using a pipe capable of monitoring the amount of ground deformation and the amount of deflection of a structure of a landslide site.SOLUTION: The landslide measuring device is a landslide measuring device formed by connecting a plurality of non-conductive flexible pipes and includes a sensor device that has a sensor 13 extending in the axial direction of a pipe 11 and generates an output according to the amount of bending of the pipe, and further includes a monitor unit for monitoring an output from the sensor device of each pipe. When the pipe is deformed due to changes in the ground, the sensor is also deformed following the bending of the pipe. Since this sensor produces an output according to the amount of bending of the pipe, the amount of bending of the pipe can be determined by monitoring this output.SELECTED DRAWING: Figure 2

Description

The present invention relates to a flexure measuring device using a pipe capable of monitoring the amount of deformation of the ground of a landslide site and the amount of flexure of a structure.

In recent years, the Meteorological Agency has announced "record short-time heavy rainfall information" and "sediment disaster warning information" in various places, and the risk of sediment-related disasters such as landslides is increasing. In landslide areas, it is extremely important to quantitatively and temporally grasp the displacement of the slip layer, which is the cause, but there is no measuring device that can withstand long-term observation, and no measuring device has been developed. As is clear from FIG. 5 of Patent Document 1, the invention filed in 2002 is also premised on the pipe strain gauges developed more than 30 years ago, which are installed in tandem in the boring hole. ing. This pipe type strain gauge has a structure in which a strain gauge is attached to the surface of the VP pipe, and after a few years after installation in the ground, the sensor section will not function due to moisture. However, if the measuring device is housed inside the VP pipe, the sensor part can be protected from moisture.

In addition, the deterioration of structures such as tunnels and bridges for roads and railways is progressing, and it is necessary to monitor the amount of deformation of structures in order to understand abnormal deformation of structures in advance, and an invention for monitoring was made. (Patent Document 2). However, the measurement environment is bad and it is difficult to monitor for a long time in a humid tunnel or a bridge exposed to wind and rain. In order to continue monitoring the amount of deformation for a long period of time, it is desirable to provide the sensing portion inside the structure or inside a member that constitutes the structure.

JP-A-2003-214812 Patent 5397767

When a pipe strain gauge buried in the soil is used for landslide observation, if the amount of deflection can be sensed inside the pipe, moisture will not deteriorate the sensing part and long-term observation will be possible. The pipe strain gauge has high sensitivity, but it also has a drawback that it scales out during a landslide where the ground changes greatly. If the dynamic range is widened, the amount of flexure at the time of landslide can be measured, and if it is possible to measure until the VP pipe breaks, it is more preferable because the recording at the time of landslide can be left without being left over.

In the case of a pipe-type strain gauge that has been used for a long time, after the strain gauge is adhered to the outer surface of a pipe made of vinyl chloride (VP), the strain gauge is waterproofed by winding a tape. Therefore, after a few years, the strain gauge deteriorates and cannot be used. Furthermore, since the signal line for the strain gauge is exposed outside the pipe, when installing the VP pipe, it is necessary to insert the signal line while inserting the VP pipe into the boring hole, which makes the signal line processing difficult. It takes a lot of time for installation work.

The strain gauge is small, and when it is attached to the outer surface of the VP pipe, only the deformation of the attached portion can be measured (close to point measurement). It is preferable to obtain the displacement information of, and linear measurement with a wide measurement range, and planar measurement with a wide measurement target are desirable.

Since a sensor used for monitoring the deformation of a bridge or the like is usually mounted on the outside of a structure such as a bridge, it is easily affected by moisture and the like and it is difficult to continue the measurement for a long period of time. If the amount of bending of a pipe can be sensed inside a stainless steel pipe, etc., the pipe with the built-in sensing portion can be attached to the ceiling or sidewall of an aged tunnel to monitor the amount of bending, and moisture does not deteriorate the sensing portion. Absent. Furthermore, if the pipe used as a material for a bridge or the like is replaced with a pipe having a built-in sensing portion and converted into a digital signal inside, the amount of bending of the bridge or the like can be monitored.

By incorporating a sensing device inside the VP pipe or inside the stainless pipe and converting it into a digital signal, the pipes containing multiple sensors can be connected and data can be transmitted via a common signal line, and a small number of signal lines can be used for multiple points. Can be monitored.

Therefore, the inventors of the present invention think that a method of detecting a displacement of the flexible pipe due to the displacement of the ground in a wide range along the long axis of the pipe is preferable, and the flexible conductive sheet is linear. The invention for use as a sensor has been conceived. When the flexible conductive sheet is stretched by the action of tension, the relative distance of the fine powdery conductive material called a filler mixed inside the flexible sheet increases, resulting in the flexible conductive sheet. It has the property of increasing the resistance value of the sheet. Therefore, if the flexible conductive sheet is bonded to the outer surface or the inner surface of the pipe and the pipe is bent in a state where it is integrated with the pipe, the flexible conductive sheet is deformed as the pipe bends, The resistance value of the flexible conductive sheet changes. By utilizing this property, the amount of displacement of the pipe due to bending in the long axis direction can be detected as a change in the resistance value of the flexible conductive sheet. A flexible conductive sheet can be adhered to the inner surface of the pipe, and electronic circuits and signal lines can be stored inside the pipe. If the signal line can be housed inside the pipe, the signal line can be easily processed when the pipe is installed.

Further, the inventors have come up with the invention of measuring the bending amount inside a metal pipe such as a stainless pipe for monitoring the bending amount of a tunnel or a bridge. The inside of a metal pipe such as a stainless pipe is in a completely shielded environment and is suitable for digitizing a sensing signal. The measurement of the amount of bending utilizes the capacitance change of the elongated electrodes arranged in the axial direction of the pipe. One pair (for example, the end or the center) of the paired electrodes is fixed to the side surface of the pipe. When the bending occurs, the electrodes move relatively and the electric capacitance between the paired electrodes changes, so that the change in the bending amount can be known from the change in the capacitance.

In landslide areas, pipe type strain gauges with a strain gauge attached to the center of a VP pipe with a length of about 1 m are arranged in tandem in the borehole to measure the amount of deflection of the VP pipe by depth. However, since the amount of deflection is detected by the point measurement with a strain gauge attached to the center of each VP pipe, it is measured when the ground near the strain gauge is greatly deformed or when there are pebbles in front of the strain gauge. The amount of flexure has a drawback that it is easily affected locally.

The present invention has been made to solve such problems. The first aspect of the present invention is defined as follows. That is,
A landslide measuring device formed by connecting a plurality of non-conductive flexible pipes,
The pipe is a sensor device that includes a sensor that is extended in the axial direction, and includes a sensor device that generates an output according to the amount of bending of the pipe.
The landslide measuring device further comprising a monitor unit for monitoring the output from the sensor device of each pipe.

According to the first aspect, the flexible pipe includes the sensor extended in the axial direction. Therefore, when the pipe is deformed due to the fluctuation of the ground or the like, the sensor is also deformed following the bending of the pipe. Since this sensor produces an output according to the amount of bending of the pipe, the amount of bending of the pipe can be specified by monitoring this output. Since the amount of bending of the pipe follows the fluctuation of the ground, the amount of bending of the pipe thus specified represents the amount of fluctuation of the ground. That is, the relationship between the bending amount of the pipe and the output of the sensor is acquired and stored in advance, and the bending amount can be obtained from the change in the output by referring to the relationship.
Even if the ground movement is local and, as a result, the force on the pipe is also local, the flexible pipe will be totally deformed, so when the ground movement is within the range of the pipe, in other words For example, if the ground movement slightly interferes with the pipe, it can be reliably measured.

The second aspect of the present invention is defined as follows. That is,
The landslide measuring device according to the first aspect, wherein the sensor device includes a flexible conductor and a conversion circuit that converts a change in electric resistance of the flexible conductor into a change in frequency.
Since the conversion circuit for converting the frequency of the electric resistance, which is defined in the above second aspect, is composed exclusively of the resistance and the capacitor, it can be provided with a simple structure and at a low cost. The circuit with a simple structure has stable output and is easy to secure durability. Further, by digitizing the output, high accuracy can be achieved and the range of the measurement range can be widened. When the material matrix of the flexible conductor is a polymer material (rubber, elastomer), its toughness is higher than that of a flexible pipe made of synthetic resin, for example. Therefore, until the flexible pipe is broken, that is, even at the deformation limit of the flexible pipe, the sensor made of the flexible conductor can generate an output (change in resistance) according to the amount of deformation. A conversion circuit having a wide measurement range can cope with such a large deformation of the flexible pipe, that is, a large resistance change of the flexible conductor.

The relationship between the amount of bending of the pipe and the electric resistance (conductivity) is acquired and stored in advance, and the amount of bending can be obtained from the change in the electric resistance (conductivity) by referring to the relationship.
The flexible conductor is preferably waterproofed to avoid the influence of disturbance on the electric resistance of the flexible conductor.

The third aspect of the present invention is defined as follows. That is,
The landslide measuring device according to the first aspect, wherein the sensor device includes a pair of electrodes facing each other, and a conversion circuit that converts a change in electric capacitance between the pair of electrodes into a change in frequency.
The conversion circuit of the third aspect defined in this way has the same operation as that of the second aspect. That is, since the conversion circuit for converting the electric capacity into the frequency is composed exclusively of the resistor and the capacitor, it can be provided with a simple structure and at a low cost. The circuit with a simple structure has stable output and is easy to secure durability. Further, by digitizing the output, high accuracy can be achieved and the range of the measurement range can be widened.

The conversion circuit employed in the second and third aspects outputs an electric signal (frequency signal) having a unique cycle according to the degree of bending of the pipe. As a result, when a pipe provided with such a conversion circuit is made continuous, it has been found that the conversion circuit of one pipe may interfere with the conversion circuit of another pipe.
In order to prevent such interference, it is preferable that the sensor device of each pipe generate the output when at least the sensor devices of other adjacent pipes are in the off state (fourth aspect).

According to the above-mentioned fourth aspect, when the conversion circuit of the sensor device provided in the pipe generates the frequency signal, the adjacent sensor device is in the stopped state and no frequency signal is output therefrom. The output of the sensor device provided in the pipe is not subjected to any disturbance, and the amount of deformation of the pipe based on ground deformation is accurately output.
In order to reliably eliminate disturbance, after turning off the sensor device provided in the adjacent pipe, after a predetermined time (taking into consideration the time constant), turn on the sensor device of the pipe to be measured. To do.

In addition, when the sensor device for one pipe is turned on in the connected body of a plurality of pies, it is preferable to turn off the sensor devices for all other pipes from the viewpoint of more accurate measurement. However, according to the study by the present inventors, if the sensor devices of the adjacent pipes are turned off, the accuracy required for the measurement of deformation due to landslide was sufficient. If the signal line such as the control line is connected to the analysis device such as the logger provided on the ground surface, the processing of the signal line is difficult and the installation cost becomes huge. Therefore,

The fifth aspect of the present invention is defined as follows. That is,
Further, a common signal line passing through each of the pipes is further provided,
The conversion circuit of each of the sensor devices is housed in a waterproof joint,
The waterproof connecting portion is a lower open case, and includes a case for accommodating the conversion circuit and a non-conductive and waterproof filling material filled in the case.
The connection line between the common signal line and the conversion circuit and the sensor is introduced into the case from the lower opening of the case and is connected to the conversion circuit. Landslide measuring device.

According to the fifth aspect described above, the connected pipes are installed in tandem in the boring hole, and the signals from the pipes are transmitted to the monitor unit installed on the ground for monitoring the signals from the pipes via the common signal line. In this case, it is not possible to completely prevent water from entering the connected body of pipes. This is because, for example, a pipe near the surface of the earth may be cracked and water may enter the inside of the pipe through the crack. Therefore, it is necessary to waterproof the electric parts in the pipe.

Here, the conversion circuit of the sensor device of each pipe is provided in the waterproof connection part that is the lower open case, connected to the common signal line, and the case is filled with a non-conductive and waterproof filler. Even if there is water from the top, water will not penetrate into the waterproof joint. Therefore, it is possible to ensure the waterproofness of the electric parts in the pipe.

The waterproofing of the electric parts (conversion circuit) itself in the pipe and the waterproofing measure of the connecting portion between this and the wiring can be dealt with in the fifth aspect described above. Of course, water resistance is also essential for the sensor itself made of a flexible conductor. Therefore,
The sixth aspect of the present invention is defined as follows. That is,
The flexible conductor is a ribbon-shaped member, which is fixed to the peripheral surface of the pipe with a waterproof fastener.
The waterproof fastener comprises a backing member made of the ribbon-shaped flexible conductor and a frame-shaped body arranged at a peripheral edge of the flexible member, the frame-shaped body being provided on the surface of the backing member and the frame-shaped body. The landslide measuring device according to the second aspect, which is watertightly fixed to the surface of the pipe.

According to the sixth aspect, the sensor is thinned by forming the flexible conductor forming the sensor into a ribbon shape. Therefore, it is possible to arrange even a small diameter pipe. As a waterproof structure for such a ribbon-shaped sensor, a waterproof fastener composed of a backing member and a frame-like body is suitable as a structure for thinly forming it.
When the ribbon-shaped flexible conductor is attached to the outside of the pipe in a watertight manner, a hole is made in the pipe, the lead wire is drawn into the pipe, and connected to the conversion circuit inside the pipe. Then, a change in the resistance value of the ribbon-shaped flexible conductor is converted into a change in frequency by the RC oscillation circuit, and the amount of bending of the flexible pipe is obtained from the change in frequency.

The seventh aspect of the present invention is defined as follows. That is,
The pair of electrodes facing each other is a conductive member having at least its facing surface coated with an insulating material, and has a first electrode fixed at a first position on the inner peripheral surface of the pipe and a second electrode at a second position. A third aspect, comprising a fixed second electrode, wherein the first position and the second position are arranged without overlapping in a projection plane parallel to the axial direction of the pipe. The landslide measuring device described in.

According to the seventh aspect described above, the pair of electrodes made of a conductive member are arranged in parallel to the axial direction of the pipe, and the respective fixing positions with respect to the inner surface of the pipe are different in the axial direction of the pipe. This causes a change in the distance between the first electrode and the second electrode when the pipe bends. This is because the external force for bending the pipe is not uniformly applied to the entire region in the axial direction of the pipe, so that the deformation of the pipe is not uniform in the axial direction. Therefore, if the relative position of the electrodes changes, the electric capacitance between the two changes. Since the facing surface of each electrode is covered with an insulating material, even if the two come into contact with each other due to the deformation of the pipe, no short circuit occurs.
The relationship between the amount of bending of the pipe and the electric capacity is acquired and stored in advance, and by referring to the relationship, the amount of bending can be obtained from the change in the electric capacity. Here, the bending amount of the pipe refers to the maximum change amount (in the direction perpendicular to the axis) of the pipe after deformation with respect to the pipe in the unloaded state. The change in capacitance is converted to a frequency by the RC circuit as in the sixth aspect, and the amount of bending of the flexible pipe is obtained from the change in frequency.

In the seventh aspect, the flexure amount of the flexible pipe is obtained from the capacitance change due to the pair of electrodes extended in the axial direction. However, the sensor pipes are arranged in tandem and the same method as in the sixth aspect is used. If it is connected to the communication line, the amount of deformation of the ground can be calculated for each depth.
When buried in a landslide area and used, it is preferable that each electrode be waterproof. For that purpose, it is preferable to cover the entire surface of each electrode with a waterproof and insulating synthetic resin material or the like (for example, fluororesin).

FIG. 1 is a schematic diagram showing a landslide measuring apparatus according to an embodiment of the present invention. FIG. 2 is a schematic view showing the structure of the pipe. FIG. 3 is a development view showing a ribbon-shaped flexible conductor and its waterproof fastener. FIG. 4 is a sectional view showing the structure of the sensor based on the resistance change. FIG. 5 is a sectional view showing the structure of another sensor. FIG. 6 is a sectional view showing the structure of the sensor based on the capacitance change. FIG. 7 is a sectional view showing the structure of another sensor based on the change in capacitance. FIG. 8 is a cross-sectional view showing the structure of another sensor based on the capacitance change. FIG. 9 shows a conversion circuit (oscillation circuit) for converting resistance change or capacity change into frequency. FIG. 10 is a diagram showing the relationship between the amount of bending of the VP 40 and the rate of change in resistance value in the test example. FIG. 11 is a schematic diagram of a measuring device that measures the data of the test example.

The landslide measuring apparatus 1 of this invention is shown in FIG. This measuring device 1 comprises a data/analysis device 5 as a monitor and a connected body of pipe units 10. The data/analysis device 5 includes a computer device, processes an output signal from each pipe unit 10 sent via the common signal line 7 by a predetermined program, and detects a deformation of the pipe unit 10. The deformation of the pipe unit 10 represents the fluctuation of the ground.
The connected body of the pipe unit 10 is inserted into the boring hole.

The detailed structure of the pipe unit 10 is shown in FIG.
The pipe unit 10 includes a pipe body 11 formed of a non-conductive and flexible material. Examples of the non-conductive and flexible material include synthetic resin such as VP. Screws for connecting to another pipe body 11 are screwed on the upper and lower ends of the pipe body 11.
The entire sensor 13 extending in the axial direction is in close contact with one side of the inner peripheral surface of the pipe body 11. As a result, the deformation of the sensor 13 follows the deformation of the pipe body 11. A ribbon-shaped conductive polymer is used for the sensor 13 as described later. Both ends of the sensor 13 are connected to the conversion circuit 21 via wirings 15 and 16.

A waterproof connecting portion 20 is fixed to the inner peripheral surface of the pipe main end 11. The waterproof connecting portion 20 is a tubular member that is open only on the lower side, that is, the upper side is closed, and is made of the same or the same kind of synthetic resin material as the pipe body 11. By forming both of them with the same or the same kind of material, it becomes easy to join them.
A conversion circuit 21 is housed inside the waterproof connecting portion 20. The common signal line 7 and the signal lines 15 and 16 from the sensor 13 are connected to the conversion circuit 21. The preventive connecting portion 20 is filled with an insulating and water-proof filler without any gap. As the filler, synthetic resin such as urethane can be used.
When the pipe body 10 is buried in the ground where groundwater exists, a weight (not shown) or a filler having a higher specific gravity than water is put in the pipe body 10 to prevent the pipe body 10 itself from rising.

3 and 4 show an example of a configuration in which the sensor 13 is attached to the inner peripheral surface of the pipe body 11.
The sensor 13 includes a ribbon-shaped flexible conductor 131, and the flexible conductor 131 is protected by a waterproof fastener. This waterproof fastener is composed of a frame-like body 135 and a backing member 134. The flexible conductor 131 is housed in the inner hole 136 of the frame-like body 135 without any gap. The outer edge of the backing member 134 coincides with the outer edge of the frame body 135. Here, the frame-shaped body 135 and the backing member 134 are formed of the same or the same type of thermoplastic resin (waterproof and waterproof) as the pipe body 11, and these are watertightly bonded or fused to each other. As a result, the flexible conductor 131 is insulated from the external environment, so that the change in the output conductivity is due solely to its deformation.

The frame-shaped body 135 and the backing member 134 can each be formed by cutting out a part of a thin-walled pipe. That is, the pipe for cutting out the frame-like body 135 can be inserted into the pipe body 11 without a gap. The thickness of this pipe is the same as the thickness of the flexible conductor 131. A pipe for cutting out the backing member 134 can be inserted into this pipe without a gap. Then, each pipe is made of the same thermoplastic resin (for example, vinyl chloride resin). Since the thickness of each pipe is thin, a thin waterproof fastener can be obtained.

FIG. 5 shows an example in which the flexible conductor 131 is covered with a sheet member 138. The sheet member 138 is made of the same or similar material as the pipe body 11, and the outer periphery of the sheet member 138 is watertightly adhered or fused to the inner peripheral surface of the pipe body 11.
According to the structure shown in FIG. 5, the structure is simplified as compared with the structures shown in FIGS. 3 and 4, so that the manufacturing cost can be reduced.
The flexible conductor 131 may be arranged on the outer peripheral surface of the pipe body 11.

FIG. 6 shows an example of another sensor 40.
The sensor 40 converts the deformation of the pipe body 11 into a capacitance change. The pair of flat plate-shaped electrodes 41, 42 extending in the axial direction of the pipe body 11 are arranged in close proximity to each other and in parallel. The first electrode 41 is fixed to the inner peripheral surface of the pipe body 11 via the first connecting body 45. The second electrode 42 is fixed to the opposing position of the pipe body 11 via the second connecting body 46. The first connecting body 45 and the second connecting body 46 are fixed at different heights in the axial direction of the pipe body 11. As a result, as shown in FIG. 6B, when the pipe body 11 is deformed, the overlapping area of the first and second electrodes is reduced. As a result, the first electrode and the second capacitance change.

FIG. 7 shows a sensor 50 of another example. This sensor 50 also comprises a pair of flat electrodes 51, 52. The first electrode 51 is connected to the pipe main body 11 by the connecting members 55 and 56 in a double-supported state. On the other hand, the second electrode 52 is parallel to the first electrode 51, and is fixed to the inner peripheral surface of the pipe body 11 in a cantilevered state by a connecting member 58. The position of the connecting body 58 of the second electrode 52 is different from the positions of the other connecting bodies 55 and 56 in the axial direction of the pipe body 11. As a result, when a load is applied to the pipe main body 11, as shown in FIG. 7B, the distance between the first electrode 51 and the second electrode 52 changes, and the electric capacitance between the two changes.
In the example of FIG. 7, the lower edge of the first electrode 51 is inserted into the side surface of the connecting member 56. As a result, the upper edge of the coupling body 56 serves as a spacer for the first electrode 51 and the second electrode 52, preventing contact between the two.

FIG. 8 shows an example of another sensor 60. The sensor 60 is composed of a flat plate-shaped first electrode 61 and an electrode 62 having a U-shaped cross section, which is arranged so as to sandwich the first electrode 61 with a space therebetween. The first electrode 61 is fixed to the inner peripheral surface of the pipe body 11 in a cantilevered state by a connecting body 65. The second electrode 62 is fixed to the inner peripheral surface of the pipe body 11 in a cantilevered state by a connecting body 68. The connecting body 65 and the connecting body 68 are located at different positions in the axial direction of the pipe body 11. As a result, when a load is applied to the pipe body 11, the first electrode 61 slides upward as shown in FIG. 8B, the overlapping area between the two changes, and the electric capacity changes.
As shown in FIG. 8B, the distance between the first electrode 61 and the second electrode 62 changes, and the electric capacitance between them changes.

In the sensor 60 of this example, as shown in FIG. 8B, the first electrode 61 and the second electrode 62 may come into contact with each other. When the two electrodes 61 and 62 are electrically connected, no electric capacitance is generated between the two electrodes. Therefore, in this example, the surface of the first electrode 61 is covered with an insulating material, preferably a waterproof material. Has been done. Examples of such a material include fluororesin (polytetraethylene).
Also in the electrodes of the examples of FIGS. 6 and 7, it is preferable that at least one of the electrodes has a surface facing the other electrode coated with an insulating material (preferably also a material having waterproofness).
Wiring is connected to each of the pair of electrodes forming the sensors 30, 40, and 50 of FIGS. 6 to 8, and this wiring is connected to the conversion circuit as shown in FIG.

FIG. 9 shows an example of the conversion circuit.
By replacing the resistance R1 with the flexible conductor 131, such a conversion circuit becomes a conversion circuit that converts a change in the electric resistance of the flexible conductor 131 into a change in frequency.
On the other hand, such a conversion circuit becomes a conversion circuit that converts a change in the electric capacitance of each of the sensors 30, 40 and 50 into a change in the frequency by replacing the capacitor with the electrodes that form the sensors 30, 40 and 50.
In each pipe unit 10, a conversion circuit 21 is housed in the waterproof connecting portion 20. The conversion circuit 21 is connected to the common signal line 7, and its output (frequency) is transmitted to the data/analysis device 5.

Since the conversion circuit 21 of each pipe unit 10 is connected in series to the common signal line 7, it is necessary to specify the source of the output to be sent.
In the circuit shown in FIG. 9A, a shutter circuit is provided at the output destination so that the output is input to the common signal line 7 at a predetermined timing. The data/analysis device 5 identifies the source of the output sent at the predetermined timing. On the other hand, in the circuit shown in FIG. 9B, a shutter circuit may be provided at the input source of the input port 2 of the Schmitt circuit so that an ON signal is input at each predetermined timing.

The converted oscillation shown in FIG. 9 outputs a weak electromagnetic wave, which may interfere with other oscillation circuits. Therefore, it is preferable that in the connected body of the pipe units 10, only the conversion circuits of one pipe are transmitted and the conversion circuits of the other pipes are stopped. When oscillating the conversion circuit 21 of at least one pipe unit 10, the oscillation circuits of the adjacent pipes are stopped from a predetermined time before the transmission timing. The on/off timing of the conversion circuit is controlled by controlling power supply from a power supply circuit (not shown). In the circuit of FIG. 9B, control can be performed at the input timing of the H signal to port 2.
As described above, by stopping the conversion circuits 21 of the adjacent pipes 10 at least, the interference from the conversion circuits 21 is not received. Therefore, the output of the converting circuit 21 in operation accurately reflects the deformation amount of the pipe body 11.

Hereinafter, FIG. 10 shows an apparatus for measuring the relationship between the amount of bending of the pipe body 11 and the change in resistance value. Specifically, a flexible conductor having a length of 900 mm and a width of 10 mm is attached to the inner surface of a VP40 (outer diameter 48, inner diameter 40) having a length of 1000 mm, the portions near both ends of the VP40 are fixed, and the central portion is hydraulically operated. It was pushed up by a jack to be deformed, and a change in electric resistance of the sensor sheet was measured as a frequency change.
FIG. 11 is a diagram showing the relationship between the amount of deflection of the VP 40 and the rate of change in resistance value, based on the data measured in FIG. It can be seen that the resistance value changes greatly even if the bending amount is small.

The present invention is not limited to the description of the embodiments and examples of the invention. Modifications are also included in the present invention within the scope that can be easily conceived by the parties without departing from the scope of the claims.

1 landslide measuring device 5 data/analyzing device 7 common signal line 10 pipe unit 11 pipe body 20 waterproof joint 21 conversion circuit 13, 40, 50, 60 sensor 131 flexible conductor 134 backing member 135 frame-like body 41, 51 , 52 first electrode 42, 52, 62 second electrode

Claims (7)

A landslide measuring device formed by connecting a plurality of non-conductive flexible pipes,
A sensor device including a sensor extended in the pipe slack axis direction, the sensor device generating an output according to a bending amount of the pipe,
The landslide measuring device further comprising a monitor unit for monitoring the output from the sensor device of each pipe. The sensor device is a flexible conductor extending in the axial direction of the flexible pipe,
The landslide measuring device according to claim 1, further comprising a conversion circuit that converts a change in electric resistance of the flexible conductor into a change in frequency. The sensor device is extended in the axial direction of the flexible pipe, and a pair of electrodes facing each other,
The landslide measuring device according to claim 1, further comprising a conversion circuit that converts a change in electric capacitance between the pair of electrodes into a change in frequency. 4. A landslide device according to claim 2 or 3, wherein the pipe sensor device produces the output when at least another adjacent pipe sensor device is off. Further, a common signal line passing through each of the pipes is further provided,
The conversion circuit of each of the sensor devices is connected to the common signal line via a waterproof connection part,
The waterproof connecting portion is a case that is open on the lower side, and includes a case that incorporates the conversion circuit and a non-conductive and waterproof filler that is filled in the case.
The connection line between the common signal line and the conversion circuit and the flexible conductor or the pair of electrodes is introduced into the case from the lower opening of the case and connected to the conversion circuit. The landslide measuring device in any one of -4. The flexible conductor is a ribbon-shaped member, which is fixed to the peripheral surface of the pipe with a waterproof fastener.
The waterproof fastener comprises a backing member made of the ribbon-shaped flexible conductor and a frame-shaped body arranged at a peripheral edge of the flexible member, the frame-shaped body being provided on the surface of the backing member and the frame-shaped body. The landslide measuring device according to claim 2, which is watertightly fixed to the surface of the pipe. The pair of electrodes facing each other is a conductive member having at least its facing surface coated with an insulating material, and has a first electrode fixed at a first position on the inner peripheral surface of the pipe and a second electrode at a second position. The second electrode is fixed, and the first position and the second position are arranged without overlapping in a projection plane parallel to the axial direction of the pipe. The landslide measuring device described.