JP5953203B2 - Pile state detection system - Google Patents

Description

  The present invention relates to a pile state detection system that detects a state of a pile.

In order to evaluate the soundness of piles during construction or disaster, it is necessary to investigate the state of pile damage and the like. As a pile condition survey, a technique of excavating the ground and visually checking the pile head or a technique of performing a nondestructive inspection using a boring mine are common. However, the method of visually observing the pile head cannot investigate the state of other parts of the pile, and the method using the boring pit needs to drill the ground near the pile diagonally while avoiding the upper frame. As a result, the survey takes enormous effort and cost.

  In view of such circumstances, as a method for evaluating the soundness of a pile, it has been proposed to embed an optical fiber in the pile and evaluate the soundness of the pile using distortion of the optical fiber (Patent Document 1, 2).

JP 2000-017656 A JP 2003-213676 A

  Since the pile constantly supports the weight of the upper frame, compression force is applied to the pile, causing compression strain. Therefore, when installing an optical fiber in a pile, the operation | work which affixes on an object, pulling an optical fiber previously is required. For this reason, such a method is complicated in installation method and construction, and has become a hindrance to popularization.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a pile state detection system that is easy to install and capable of suitably detecting the state of a pile.

In order to solve the above problems, a pile state detection system of the present invention is provided on a pile, connected to the state detection sensor for detecting the state of the pile, and the state detection sensor, and the detection of the state detection sensor. An IC tag that transmits a result, and a reader that is arranged in a monitoring pit formed along the pile and receives the detection result of the state detection sensor transmitted from the IC tag. .

  According to this configuration, since the set of the state detection sensor and the IC tag is installed in the pile, it is easier to install than the case where the optical fiber is embedded in the pile, and the variation of the pile is suppressed. The state can be detected suitably.

Pile state detection system includes a moving portion for moving the reader, the depth detector for detecting the depth of the leader in the monitoring in the pit, when the highest field intensity of the received result of the detection by said reader And a data processing unit that employs the depth of the above.

  According to such a configuration, it is possible to detect a change in the state of the pile in the depth direction (presence of subsidence) or the like.

  The plurality of sets of state detection sensors and the IC tags arranged in the depth direction of the pile, each of the plurality of IC tags transmits the detection result using a different frequency, and the data processing unit A spectrum analyzer function for detecting the frequency and the radio wave intensity of the detection result, and the depth when the radio wave intensity of the detection result at the corresponding frequency is the highest based on the frequency of the detection result stored in advance. The structure which employ | adopts this may be sufficient.

Further, the pile state detection system may include a plurality of readers arranged in the depth direction of the monitoring well corresponding to the plurality of sets of state detection sensors and the IC tags.

  According to the present invention, it is easy to install a state detection sensor and a set of IC tags, and the state of a pile can be suitably detected.

It is a mimetic diagram showing a pile state detection system concerning a first embodiment of the present invention. It is X arrow sectional drawing of FIG. (A)-(c) is a graph which shows the relationship between the frequency and radio wave intensity in the signal which the reader | leader received in each depth position. It is a figure which shows an example of the display screen in a notification part. It is a schematic diagram which shows the pile state detection system which concerns on 2nd embodiment of this invention.

  Hereinafter, a pile state detection system according to an embodiment of the present invention will be described with reference to the drawings as appropriate. Similar components are denoted by the same reference numerals, and redundant description is omitted.

<First embodiment>
As shown in FIG. 1, a pile state detection system 10 </ b> A according to the first embodiment of the present invention is a system that detects the state of a pile 3 by applying the upper frame 2 to a plurality of piles 3 formed on the top. is there. In the vicinity of one pile 3, a monitoring pit 4 is excavated and formed along the pile 3. In FIG. 1, the pile 3 before the disaster is depicted with a dotted line, and the pile 3 after the disaster is depicted with a solid line.

  The pile state detection system 10 </ b> A includes a plurality of sets (here, three sets) of state detection sensors 11 and IC tags 12, one reader 13, and a moving unit 14 arranged in the depth direction of one pile 3. , An operation unit 15, a control unit 16 </ b> A, and a notification unit 17.

<Status detection sensor>
The state detection sensor 11 is provided at a predetermined depth of the pile 3, detects the state of the pile 3, and outputs a detection result to the IC tag 12. As the state detection sensor 11, an inclination sensor that detects the inclination of the pile 3, a strain sensor that detects distortion of the pile 3, and the like are preferably used.

<IC tag>
The IC tag 12 is provided at a predetermined depth of the pile 3, that is, at the same depth position as the corresponding state detection sensor 11, and transmits the detection result of the state detection sensor 11 to the reader 13. Each IC tag 12 transmits the ID of the IC tag 12 together with the detection result, and the frequency of the transmitted radio wave (a signal including the detection result and the ID) is different for each IC tag 12. In this embodiment, the top IC tag 12 has ID = 1, frequency f = α [Hz], and the center IC tag 12 has ID = 2, frequency f = β [Hz], bottom IC. The tag 12 has ID = 3 and frequency f = γ [Hz], and each frequency f is set to α <β <γ. In this embodiment, the IC tag 12 is a passive IC tag that operates using electromagnetic induction from the reader 13 as a power source. However, the IC tag 12 is not limited to the passive type, and is a semi-active type or an active type. It may be. In this embodiment, the IC tag 12 employs an electromagnetic induction method. However, as long as communication with the reader 13 is possible, radio waves (or power and data can be transmitted and received under any conditions in the ground. A frequency band of a magnetic field, a magnet, etc.) may be adopted.
<Pile>

As shown in FIG. 2, the pile 3 includes a plurality of reinforcing bars (pile main bars) 3 a that are arranged in a circular shape in plan view and extend in the depth direction, and an annular reinforcing bar (hoop) 3 b that is assembled to the plurality of reinforcing bars 3 a. . The state detection sensor 11 and the IC tag 12 are installed in the pile 3 in advance when the pile 3 is constructed. In the present embodiment, the state detection sensor 11 is attached to one reinforcing bar 3 a and embedded in the pile 3. The IC tag 12 is electrically connected to the state detection sensor 11 via a conductive wire or the like, and is provided on the monitoring well 4 side of the outer peripheral surface of the pile 3.

As shown in FIG. 1, a plurality of sets of state detection sensors 11 and IC tags 12 are arranged at a predetermined interval in the axial direction of the pile 3. 11 and the IC tag 12 have a depth of 1 m from the ground surface, the center state detection sensor 11 and the IC tag 12 have a depth of 2 m from the ground surface, and the bottom state detection sensor 11 and the IC tag 12 They are arranged with a depth of 3 m from the surface and an interval of 1 m in the depth direction. Note that the interval between the set of the state detection sensor 11 and the IC tag 12 is not limited to 1 m, and can be changed as appropriate. The monitoring well 4 is formed to the same depth as at least the lowest state detection sensor 11 and the IC tag 12. The monitoring well 4 is desirably formed to a position deeper than the lowest state detection sensor 11 and the IC tag 12.

<Construction technique for the state detection sensor and IC tag in the pile>
In the present embodiment, the state detection sensor 11 is fixed to the reinforcing bar 3 a via a sensor fixing jig 21. The IC tag 12 is electrically connected to the state detection sensor 11 via a sensor fixing jig 21 and a tag position fixing spring 22.

The tag position fixing spring 22 is a compression spring capable of urging the IC tag 12 toward the surface of the pile 3 and has any of the following characteristics.
-Shape memory alloy.
・ Extend when scheduled.
• It is compressed by a band (not shown) and stretches when the band breaks due to reaction with water or concrete.

  The tag position fixing spring 22 is compressed before the concrete is placed on the pile 3 and is released from the compression when the concrete is placed, and is stretched to suitably arrange the IC tag 12 on the surface of the pile 3. Can do. According to this configuration, when inserting the reinforcing bar with the state detection sensor 11 and the IC tag 12 into the excavation hole when the pile 3 is constructed, the IC tag 12 is arranged inside the reinforcing bar and Collision with the peripheral wall is prevented, and after construction of the pile 3, the IC tag 12 is arranged on the surface of the pile 3 so that wireless communication is suitably performed.

<Reader>
The reader 13 transmits radio waves toward the IC tag 12 and communicates with the IC tag 12 to read information in the IC tag. The detection result of the state detection sensor 11 transmitted from the IC tag 12 The ID of the IC tag 12 is received and output to the control unit 16A. The reader 13 has a waterproof function and a dust-proof function, and can transmit and receive power and data to and from the IC tag 12 even when ground water, muddy water, or the like is present in the monitoring pit 4. . Moreover, the shape of the reader | leader 13 is arbitrary, For example, it can be set as flat form, cylinder shape, etc.

  In the present embodiment, the reader 13 outputs a signal including the detection result and ID transmitted from the IC tag 12 to the control unit 16.

<Moving part>
The moving unit 14 includes a rope 14a having one end connected to the leader 13, a roller 14b around which the other end of the rope 14a is fixed and wound around the rope 14a, and a motor 14c that rotates the roller 14b. A rope 14a is wound around the roller 14b. When the motor 14c rotates in the forward direction, the rope 14a is sent out from the roller 14b and the leader 13 moves downward in the monitoring well 4, and the motor 14c rotates in the reverse direction. Then, the rope 14 a is wound around the roller 14 b and the leader 13 moves upward in the monitoring pit 4.

<Operation unit>
The operation unit 15 is a switch for switching ON / OFF of the motor 14c.

<Control unit>
The control unit 16A includes a motor control unit 16a, a depth calculation unit 16b, a data processing unit 16c, and a storage unit 16d as functional units.

  The motor control unit 16a rotates the motor 14c at a predetermined rotation speed in accordance with the operation of the operation unit 15 by the operator.

The depth calculation unit 16b is an example of a depth detection unit that detects the depth position of the reader 13 in the monitoring pit 4, and determines the rotation speed of the motor 14c, the driving time of the motor 14c, and the radius of the roller 14b. Based on this, the depth position of the reader 13 in the monitoring well 4 is calculated and output to the data processing unit 16c. When the motor 14c is equipped with an encoder, the depth calculation unit 16b may calculate the depth position of the reader 13 based on the rotation speed (rotation angle) of the motor 14c detected by the encoder. The method for detecting the depth position of the reader 13 is not limited to the above-described one. For example, a scale indicating the depth position of the reader 13 is written in the length direction of the rope 14 a, and the inside of the monitoring pit 4 is indicated in the reader 13. When the user moves, the depth of the reader 13 may be detected by the user reading the scale and operating the operation unit 15 to input.

  The data processing unit 16 c has a spectrum analyzer function that detects the radio wave intensity of the detection result radio wave transmitted from the IC tag 12 and generates a spectrum indicating the relationship between the frequency and the radio wave intensity, and is output by the reader 13. On the basis of the detection result, the ID and the radio wave intensity, and the depth position calculated by the depth calculation unit 16b, for each state detection sensor 11, the radio wave intensity, detection result, and The depth position is stored in the storage unit 16d or output to the notification unit 17. The storage unit 16d stores in advance the frequencies α, β, and γ of each IC tag 12.

<Notification part>
The notification unit 17 is a monitor that displays detection results and the like output by the data processing unit 16c. Note that the notification unit 17 may be a speaker that notifies the detection result or the like output by the data processing unit 16c by voice.

<Operation example>
Subsequently, an operation example of the pile state detection system 10A will be described.

<Before disaster>
When the pile state detection system 10A is activated before the disaster, the motor control unit 16a rotates the motor 14c at a predetermined rotational speed to lower the reader 13 from the vicinity of the opening of the monitoring pit 4 toward the bottom, 13 communicates with the IC tag 12 and receives the detection result of the state detection sensor 11. Specifically, when the reader 13 approaches the IC tag 12 while transmitting radio waves, an electromotive force is generated in the IC tag 12 by the radio waves transmitted by the reader 13, and the IC chip in the IC tag 12 is activated. Then, the IC tag 12 supplies power to the state detection sensor 11, the state detection sensor 11 detects the state of the pile 3 and outputs the detection result to the IC tag 12, and the IC tag 12 reads the detection result. Send to.

Here, for example, when the reader 13 is at a position shallower than the depth 1 m of the monitoring well 4 (here, 0.5 m), the radio wave intensity of the radio wave received by the reader 13 as shown in FIG. The radio wave from the top IC tag 12 closest to the reader 13 is the largest. When the reader 13 is located at a depth of 1 m in the monitoring well 4 (that is, the same depth position as the top IC tag 12), as shown in FIG. The radio wave intensity increases, and the radio wave intensity of the radio wave received by the reader 13 is the highest from the top IC tag 12 closest to the reader 13. When the reader 13 is at a position deeper than the depth 1 m of the monitoring well 4 (here, 1.5 m), the radio wave intensity from the top IC tag decreases, and the center and bottom ICs The radio wave intensity from the tag 12 increases. In this way, the data processing unit 16c measures the shape of the spectrum that changes every moment and stores it in the storage unit 16d, and the maximum radio field intensity at the specific frequencies α, β, and γ stored in the storage unit 16d. By specifying the value, after the reader 13 is lowered to the bottom of the monitoring well 4 and the detection is finished, each of the state detection sensors 11 has the highest radio wave intensity (the distance between the IC tag 12 and the reader 13 is The radio field intensity, the detection result, and the depth position (when the IC tag 12 and the reader are at the same depth position) are stored in the storage unit 16d. Subsequently, the motor control unit 16 a rotates the motor 14 c in the reverse direction to lift the reader 13 from the bottom of the monitoring pit 4. The maximum value of the radio wave intensity can be specified while lifting the reader 13 from the bottom of the monitoring pit 4.

<After disaster>
After the disaster, the pile state detection system 10A operates in the same manner as before the disaster. Then, the data processing unit 16c notifies the radio field strength, the detection result, and the depth position when the radio field strength is the highest for each state detection sensor 11 stored in the storage unit 16d before and after the disaster. Output to and display. An example of the display screen is shown in FIG. As shown in FIG. 4, the detection result before the disaster (20XX year MM month DD day) and the detection result after the disaster (20XX year NN month EE day) are displayed side by side on the display screen.

According to the pile state detection system 10 </ b> A according to the first embodiment of the present invention, as shown in FIG. 4, the detection result of the state detection sensor 11 after a disaster (for example, an inclination angle and a distortion amount) is displayed on the display screen. At the same time, the depth position of the IC tag 12 is displayed. Therefore, it is possible to inform the worker of the state of the pile 3 for each part.
The display screen displays the detection results of the state detection sensor 11 before and after the disaster, respectively. Therefore, the pile state detection system 10A can notify the worker of the state of the pile 3 due to the disaster for each part.
Also, the display screen displays the depth position when the radio wave intensity is the highest before and after the disaster. Therefore, the pile state detection system 10 </ b> A can notify the operator of a change in the state of the pile 3 in the depth direction (presence of subsidence).
Moreover, since the pile state detection system 10A installs the set of the state detection sensor 11 such as the tilt sensor and the IC tag 12 on the pile 3, compared with the case where the optical fiber is embedded in the pile, the variation in the installation is less. It can suppress and can detect the state of the pile 3 suitably.

<Second Embodiment>
Subsequently, the pile state detection system according to the second embodiment of the present invention will be described focusing on differences from the pile state detection system according to the first embodiment.

  As shown in FIG. 5, the pile state detection system 10 </ b> B according to the second embodiment of the present invention does not include the moving unit 14, and includes a plurality of (here, three) readers 13 and a plurality of readers 13. And rod-shaped members 18 attached at predetermined intervals. Furthermore, the pile state detection system 10B includes a control unit 16B that does not include the motor control unit 16a and the depth calculation unit 16b in place of the control unit 16A.

The rod-shaped member 18 has a size that can be inserted into the monitoring well 4, and a flange portion 18a is formed at the upper end thereof. When the rod-shaped member 18 is inserted into the monitoring pit 4, the flange portion 18a is placed on the ground surface around the opening of the monitoring pit 4, and the top leader 13, the center leader 13, and the bottom leader 13 are , Arranged in the depth direction with an interval of 1 m.

Further, the bar-shaped member 18 is longer than the pile 3, and the lowermost leader 13 is provided at the tip of the bar-shaped member 18. This is because the IC tag 12 and the reader 13 that were at the same depth position are expected not to be at the same depth position when the pile 3 is broken due to an earthquake or the like. In such a pile state detection system 10B, Each reader 13 reads the ID and the like from the IC tag 12 while checking the depth position of each reader 13 while pulling out the rod-shaped member 18 from the monitoring well 4.

The rod-shaped member 18 is formed from a flexible cylindrical tube. This is because the rod-shaped member 18 can be suitably pulled out even when the monitoring well 4 is distorted due to an earthquake or the like.

The reader 13 pre-stores its own depth position when installed in the monitoring well 4, and each reader 13 is connected to the control unit 16B in a star-type manner so as to be able to communicate with the IC tag. 12 outputs the detection result outputted by 12 and its own depth position to the control unit 16B.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A design change is possible suitably in the range which does not deviate from the summary of this invention. For example, the radio wave intensity of the IC tag 12 or the distance between the pile 3 and the monitoring well 4 may be set so that the reader 13 can receive only the radio wave from the nearest IC tag 12. As a modification, when the state detection sensor 11 in the first embodiment is omitted, only the deformation of the pile 3 in the depth direction can be notified to the operator.

3 pile 4 monitoring well 10A, 10B pile state detection system 11 state detection sensor 12 IC tag 13 reader 14 moving unit 16A, 16B control unit 16b depth calculation unit (depth detection unit)
16c Data processing unit

Claims (4)

A state detection sensor that is provided on the pile and detects the state of the pile;
An IC tag connected to the state detection sensor and transmitting a detection result of the state detection sensor;
A reader that is arranged in a monitoring well formed along the pile and receives the detection result of the state detection sensor transmitted from the IC tag;
A pile state detection system comprising: A moving unit for moving the reader;
The depth detector for detecting the depth of the leader in the monitoring in the pit,
A data processing unit adopting the depth when the radio wave intensity of the detection result received by the reader is highest;
The pile state detection system according to claim 1, comprising: A plurality of sets of the state detection sensors arranged in the depth direction of the pile and the IC tag,
The plurality of IC tags transmit the detection results using different frequencies, respectively.
The data processing unit has a spectrum analyzer function for detecting the frequency and radio wave intensity of the detection result, and based on the frequency of the detection result stored in advance, the radio wave intensity of the detection result at the corresponding frequency. The pile state detection system according to claim 2, wherein a depth at the highest time is adopted. The pile state detection system according to claim 1, comprising a plurality of the readers arranged in the depth direction of the monitoring well corresponding to a plurality of sets of the state detection sensors and the IC tags.

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