Sensor for measuring penetration depth of steel structure, sensor device for measuring penetration depth of steel structure, and method for measuring penetration depth of steel structure using the same

Abstract

To accurately and surely measure the embedment of a steel structure without being affected by the individual difference of an impact force when the embedment of the steel structure is measured by an impact elastic wave measuring method.SOLUTION: This device is provided with a solenoid 5 housed in a solenoid case 2 having an opening part 4 in such a manner that a plunger 6 is projected to the opening part side, a hammer 7 provided at the tip of the plunger, a sensor holder 9 mounted on the opening part side of the solenoid case, a sensor 1 provided with a sensor body 10 housed in the sensor holder in such a manner that the sensor body is hit by the hammer when the plunger is projected, and a device body 22 for analyzing the output of the sensor body. The elastic wave and the reflected wave from the steel structure are detected by the sensor body and converted into a predetermined signal, and the converted signal is analyzed by the device body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sensor for measuring the embedded depth of a steel structure, used to measure the embedded depth of a steel structure such as an installed long rock bolt, a steel sheet pile, or a pile, a sensor device for measuring the embedded depth of a steel structure, and a method for measuring the embedded depth of a steel structure using the same. [Background technology]

[0002] There has long been a demand for measuring the embedded depth of steel structures, such as long rock bolts, steel sheet piles, and piles, that have already been installed. Specifically, when repairing or rebuilding a structure, it is necessary to know the embedded depth of the rock bolts, steel sheet piles, and piles used in the original construction. However, if a long time has passed since the original construction, the original construction drawings are often lost. Therefore, when the original construction drawings are lost, some method is required to determine the embedded depth of previously installed steel structures, such as long rock bolts, steel sheet piles, and piles. Therefore, conventional methods for measuring the embedded depth of steel structures have been to use ultrasonic technology (P waves or SH waves) or impact elastic wave measurement using a hammer.

[0003] For example, an impact elastic wave measurement method for investigating internal defects in steel structures uses an impact hammer that impacts the surface of the structure, a sensor such as an acceleration sensor that detects elastic waves from the steel structure impacted by the impact hammer and reflected waves from the steel structure, and an analyzer that receives and analyzes the signals from the sensor to measure the condition of the steel structure.The impact hammer impacts the steel structure to generate elastic waves in the structure, and the generated elastic waves and reflected waves reflected from the tip of the steel structure are detected by the sensor, and the detected elastic waves and reflected waves are analyzed by the analyzer to measure the length of the steel structure.Therefore, by adopting this method, it is possible to measure the embedded depth of steel structures such as long rock bolts, steel sheet piles, and piles that have already been installed without destroying the steel structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-144586 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-20425 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-211333 [Patent Document 4] Japanese Patent Application Laid-Open No. 2017-133936 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned method using ultrasonic application technology and the impact elastic wave measurement method have the following problems.

[0006] Both the ultrasonic application technology method and the impact elastic wave measurement method apply elastic waves to the head of the steel structure whose embedment depth is to be measured, and measure the overall length or the distance to the crack by capturing the reflected waves from the tip or crack. However, with the ultrasonic application technology method, there are many cases where measurements cannot be made because the transmitted energy is small and there is a large loss of sound waves.

[0007] Furthermore, in the impact elastic wave measurement method, because the steel structure is struck with an impact hammer, there are many cases where measurement is difficult due to measurement errors caused by individual differences in striking force and errors due to the low frequency of the generated waves.

[0008] Therefore, an object of the present invention is to provide a sensor device for use in measuring the embeddedness of steel structures, which enables accurate and reliable measurement of the embedded depth of steel structures without being affected by individual differences in impact force when measuring the embeddedness of steel structures using an impact elastic wave measurement method, and a method for measuring embeddedness of steel structures using the same. [Means for solving the problem]

[0009] The sensor for measuring the embedment depth of a steel structure of the present invention is A sensor for measuring the embedment depth of a steel structure, for measuring the embedment depth of a steel structure, a solenoid case having an opening at one end thereof; a solenoid housed in the solenoid case with a plunger protruding toward an opening of the solenoid case; a hammer portion provided at the tip of the plunger of the solenoid; a sensor holder attached to the opening side of the solenoid case; a sensor body accommodated in the sensor holder in such a position that the plunger of the solenoid is struck by the hammer portion when the plunger of the solenoid projects from the solenoid body, The sensor body is brought into contact with the steel structure to be measured, In this state, the solenoid is driven, the plunger is extended, and the hammer part strikes the sensor body, thereby giving an impact to the sensor body and generating elastic waves in the sensor body, and transmitting the generated elastic waves to the steel structure. The sensor detects the generated elastic waves and the waves reflected from the steel structure, converts them into a predetermined signal, and outputs it.

[0010] Further, the sensor device for measuring the embedment depth of a steel structure of the present invention is A sensor device for measuring the embedment depth of a steel structure, for measuring the embedment depth of a steel structure, a solenoid case having an opening at one end thereof; a solenoid housed in the solenoid case with a plunger protruding toward an opening of the solenoid case; a hammer portion provided at the tip of the plunger of the solenoid; a sensor holder attached to the opening side of the solenoid case; a sensor body accommodated in the sensor holder in such a position that the plunger of the solenoid is struck by the hammer portion when the plunger of the solenoid projects from the solenoid body, a sensor that brings the sensor body into contact with the steel structure to be measured, and in that state, activates the solenoid, protrudes the plunger, and strikes the sensor body with the hammer, thereby generating elastic waves in the sensor body and transmitting the generated elastic waves to the steel structure, and detects the generated elastic waves and the waves reflected from the steel structure with the sensor body, converts them into a predetermined signal, and outputs the signal; The device is characterized by comprising a device main body that controls the operation of the sensor and measures the embedment depth of the steel structure by analyzing the predetermined signal output from the sensor main body.

[0011] The method for measuring the penetration depth of a steel structure of the present invention using the sensor device for measuring the penetration depth of a steel structure having this configuration is as follows: The sensor body is brought into contact with the steel structure to be measured, In this state, the solenoid is driven, the plunger is extended, and the hammer part strikes the sensor body, thereby giving an impact to the sensor body and generating elastic waves in the sensor body, and transmitting the generated elastic waves to the steel structure. The sensor detects the generated elastic waves and the waves reflected from the steel structure and converts them into a predetermined signal. The elastic waves and the reflected waves converted into the predetermined signals are transmitted to the device body, The device is characterized in that the received predetermined signal is analyzed in the device body, and the embedded depth of the steel structure is measured and output. [Effects of the Invention]

[0012] In the present invention, a solenoid is used to impact the sensor body to generate elastic waves, which are then transmitted to the steel structure via the sensor body, so there is no individual difference in impact force and no measurement error.

[0013] Furthermore, the impact force can be adjusted by controlling the driving voltage for driving the solenoid, so that the impact force of the hammer can be made extremely large, which allows high frequency components to be obtained in the elastic waves and reflected waves, making it possible to measure with high resolution.

[0014] Furthermore, because the method uses a solenoid to deliver impacts, unlike manual impacts, it is possible to deliver impacts repeatedly at regular time intervals, which is also effective in performing averaging to improve the signal-to-noise ratio of weak signals, and it is also possible to preset the number of impacts and the interval (time) between impacts.

[0015] Therefore, according to the present invention, when performing an impact elastic wave measurement method in which an impact is applied to a structure to generate elastic waves, and the elastic waves and reflected waves are analyzed to measure the embedded depth of a steel structure, it is possible to accurately and reliably measure the embedded depth of a steel structure without being affected by individual differences in the impact force. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a partial cross-sectional view for explaining the configuration of an embodiment of a sensor for measuring embedded depth of a steel structure according to the present invention. [Figure 2] 1 is an image diagram for explaining the configuration of an embodiment of a sensor device for measuring the embedded depth of a steel structure according to the present invention. FIG. [Figure 3] FIG. 1 is a diagram for explaining a control device in an embodiment of a sensor device for measuring embedded depth of a steel structure according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The sensor for measuring the embedment depth of steel structures of the present invention has a solenoid case with one end open to form an opening, and a solenoid is housed within this solenoid case with a plunger protruding toward the opening side of the solenoid case, and the tip of the plunger in this solenoid is equipped with a hammer part such as an impact hammer.

[0018] A sensor holder is attached to the opening side of the solenoid case, and the sensor body such as an acceleration sensor or AE sensor is housed inside the sensor holder.

[0019] The sensor body is housed in the sensor holder in such a position that when the solenoid is driven and the plunger protrudes from the solenoid body, it is struck by the hammer portion at the tip of the plunger.

[0020] In this configuration, the sensor body is brought into contact with the steel structure to be measured, and in that state, the solenoid is driven, the plunger is extended, and the hammer part strikes the sensor body, causing an impact on the sensor body to generate elastic waves in the sensor body, which are then transmitted to the steel structure.The generated elastic waves and the reflected waves from the steel structure are then detected by the sensor body, converted into a specified signal, and output.

[0021] In addition, the sensor device for measuring the embedment depth of steel structures of the present invention is equipped with a device main body in addition to the above-mentioned sensor configuration, and this device main body controls the operation of the sensor and analyzes the signal output from the sensor main body in the sensor to measure the embedment depth of the steel structure.

[0022] In the method for measuring the embedment depth of a steel structure of the present invention for measuring the embedment depth of a steel structure using this sensor device for measuring the embedment depth of a steel structure, first, the sensor body is brought into contact with the steel structure to be measured.

[0023] Next, in this state, the solenoid is driven, causing the plunger to extend and the hammer part to strike the sensor body, thereby impacting the sensor body and generating elastic waves in the sensor body, and at the same time, transmitting the generated elastic waves to the steel structure.

[0024] The sensor body detects the elastic waves generated by the sensor and the waves reflected from the steel structure, converts them into predetermined signals, and transmits the converted elastic waves and reflected waves to the device body.

[0025] The device main body then analyzes the received predetermined signal, measures the embedment depth of the steel structure, and outputs the result. [Example]

[0026] An embodiment of the sensor for measuring the embedment depth of steel structures (hereinafter simply referred to as "sensor") of the present invention will be described with reference to the drawings. Figure 1 is a schematic partial cross-sectional view for explaining the structure of the sensor of this embodiment, in which 1 is the sensor of this embodiment, with the upper side being the base end side and the lower side being the tip end side.

[0027] The sensor 1 of this embodiment generates elastic waves, transmits the generated elastic waves to the steel structure, detects the reflected waves reflected from the tip or cracks of the steel structure, converts the generated elastic waves and the reflected waves into a specified electrical signal and outputs it, which can be used to measure the embedment depth of the steel structure.

[0028] In the figure, the sensor 1 has a solenoid case 2, which is open at the base end and the tip end, with the opening at the base end being closed by a top cover 3 and the opening at the tip end being an opening 4.

[0029] A solenoid is housed and fixed inside the solenoid case 2. In this embodiment, a push-type solenoid is used. That is, the solenoid is configured so that a plunger pops out when a switch is pressed, and this solenoid is fixed inside the solenoid case 2 in an arrangement where the plunger pops out toward the opening 4.

[0030] In the figure, 5 is a solenoid, 6 is a plunger, and 8 is a striking switch for energizing the coil of the solenoid 5 to eject the plunger 6; turning on this striking switch 8 causes the plunger 6 to eject. Also in the figure, 7 is a hammer attached to the end of the plunger 6 on the opening 4 side (hereinafter referred to as the "tip"), and in this embodiment, an impact hammer is used as the hammer. Since solenoids are well known, a description of their structure will be omitted.

[0031] Next, in the drawing, reference numeral 9 denotes a sensor holder. That is, in this embodiment, a sensor holder 9 is attached to the tip side of the solenoid case 2, and a sensor main body 10 is housed inside this sensor holder 9.

[0032] The sensor body 10 is used to detect elastic waves and reflected waves, convert these elastic waves and reflected waves into predetermined signals, and output them. In this embodiment, the sensor body 10 uses an acceleration sensor, and is housed within the sensor holder 9 with its tip end protruding beyond the tip of the sensor holder 9.

[0033] Furthermore, sensor main body 10 is housed in sensor holder 9 in an arrangement such that when striking switch 8 is turned on and solenoid 5 is energized, causing plunger 6 of solenoid 5 to jump out from solenoid 5, the base end (hereinafter referred to as "head") is struck by impact hammer 7. That is, in this embodiment, solenoid 5 is arranged so that when solenoid 5 is energized, plunger 6 jumps out below solenoid case 2 and the tip of plunger 6 is positioned within sensor holder 8, allowing impact hammer 7 to strike the head of sensor main body 10. The state in which the impact hammer 7 strikes the head of sensor main body 10 is shown in FIG. 1 .

[0034] Next, in the figure, reference numeral 11 denotes a rubber sheet for preventing noise from being applied to the sensor body 10 when struck by the impact hammer 7, and covers the entire side surface of the sensor body 10 at least within the sensor holder 9.

[0035] The sensor body used in the present invention does not necessarily have to be an acceleration sensor, but can be anything that can detect the generated elastic waves, convert the detected elastic waves into an electrical signal, and output it, for example, an AE sensor.

[0036] Next, in the figure, reference numerals 13, 14, and 15 denote electric wires, and 13 is a signal wire for transmitting a predetermined electric signal output from sensor main body 10 to the outside, with one end connected to connector 17 of sensor main body 10. 14 is a signal wire for outputting an electric signal indicating that impact switch 8 has been turned on when impact switch 8 is turned on, and 15 is a power supply wire for applying a predetermined voltage of electricity to the solenoid coil. These electric wires 13, 14, and 15 pass through solenoid case 2 and are connected to cable gland 12 provided in the upper part of solenoid case 2.

[0037] When the sensor 1 is in use, a signal wire protection tube 16 is connected to the cable gland 12, and the signal wire protection tube 16 houses the electric wires 13, 14, 15 to which the electric wires 13, 14, 15 are connected. The electric wires 13, 14, 15 are then connected to an analyzer or the like via the signal wire protection tube 16, thereby allowing the operation of the sensor 1 to be controlled by the analyzer or the like, and enabling the signal output from the sensor main body 10 to be analyzed by the analyzer.

[0038] Next, the operation of the sensor 1 of this embodiment will be explained. When using the sensor 1 of this embodiment to measure the embedded depth of a steel structure, the tip of the sensor body 10 is brought into contact with the steel structure to be measured.

[0039] Next, in this state, the impact switch 8 is turned on to energize the coil of the solenoid 5, causing the plunger 6 of the solenoid 5 to jump out from the body of the solenoid 5, and the impact hammer 7 at the tip of the plunger 6 strikes the head of the sensor body 10, giving an impact to the sensor body 10.

[0040] When this is done, first, an elastic wave is generated in the sensor body 10, and this generated elastic wave is detected by the sensor body 10. At the same time, the generated elastic wave is transmitted to the steel structure, since the tip of the sensor body 10 is in contact with the steel structure to be measured.

[0041] Next, the elastic waves transmitted to the steel structure travel along the steel structure toward the tip of the steel structure. When the elastic waves traveling along the steel structure reach a point with characteristics different from those of the steel structure from which they traveled, such as the tip or a crack, they become reflected waves and are reflected toward the sensor body 10.

[0042] The sensor body 10 then detects the reflected wave and converts this reflected wave, along with the initially generated elastic wave, into a predetermined electrical signal, and outputs the elastic wave and the reflected wave converted into the predetermined electrical signal to an analysis device or the like via the signal line 13.

[0043] In this way, in the sensor 1 of this embodiment, the solenoid 5 is used to apply an impact to the sensor body 10 to generate an elastic wave, so there is no individual difference in the impact force.

[0044] Furthermore, the impact force can be adjusted by controlling the drive voltage for driving the solenoid 5, so that the impact force of the impact hammer 7 can be made extremely large, thereby obtaining high frequency components in the elastic waves and reflected waves, making it possible to measure with high resolution.

[0045] Furthermore, because the method uses a solenoid to deliver impacts, unlike manual impacts, it is possible to deliver impacts repeatedly at regular time intervals, which is also effective in performing averaging to improve the signal-to-noise ratio of weak signals, and it is also possible to preset the number of impacts and the interval (time) between impacts.

[0046] There are already many types of sensors commercially available that detect elastic waves and reflected waves and convert them into predetermined electrical signals, and the methods for detecting elastic waves and reflected waves and converting them into predetermined electrical signals are well known and vary depending on the sensor, so details will be omitted.

[0047] Next, an embodiment of a sensor device for measuring the embedded depth of a steel structure (hereinafter simply referred to as "sensor device") of the present invention will be described with reference to the drawings. Fig. 2 is a diagram showing an image of the configuration of the sensor device of this embodiment, in which 21 is the sensor device. The sensor device 21 of this embodiment is configured to include the above-mentioned sensor 1 and a device main body 22 that controls the operation of the solenoid 5 in the sensor 1 and further measures the embedded depth of the steel structure using the elastic waves and reflected waves output from the sensor main body 10.

[0048] The device main body 22 is equipped with a control device 23 and a processing device 24, and in this embodiment, the processing device 24 uses a personal computer, and software capable of calculating the embedment depth of a steel structure is pre-installed on the personal computer.

[0049] The control device 23 is used to control the operation of the solenoid 5, and is also used to amplify the electrical signal output from the sensor main body 10 so that it can be easily analyzed by the personal computer 24. That is, the personal computer 24 sets the number of times and intervals at which voltage is applied to the solenoid 5, and based on this setting, the control device 22 applies a predetermined voltage to the solenoid 5 at predetermined intervals. The electrical signal amplified by the control device 23 is sent to the personal computer 24 as the processing device, and the personal computer 24 calculates the embedment depth of the steel structure using the transmitted elastic waves and reflected waves.

[0050] The configuration of the control device 23 will now be described with reference to Figure 3. Figure 3 is a diagram for explaining the configuration of the control device 23, in which 23 is the control device. Also in the figure, 10 is an acceleration sensor serving as the sensor body, 5 is a solenoid, and 8 is a striking switch. The acceleration sensor 10, solenoid 5, and striking switch 8 are connected to the control device 23 via the electric wires 13, 14, and 15 housed in a signal wire protection tube 16, respectively.

[0051] The control device 23 includes a preamplifier 25 for amplifying the elastic wave and reflected wave signals output from the sensor main body 10. The preamplifier 25 is connected to a filter 26, which is connected to an A / D converter 27, which is connected to a personal computer 24. The elastic wave and reflected wave signals output from the acceleration sensor 10 are first amplified by the preamplifier 25, and then the filter 26 extracts only the parts necessary for analysis and measurement, such as high-frequency components. The output of the filter 26 is then A / D converted by the A / D converter 27 and output to the personal computer 24 via, for example, a USB cable. The personal computer 24 measures the propagation time of the elastic wave and calculates the embedded depth of the steel structure being measured. The propagation time is calculated using the time when the elastic wave is generated and the time when the reflected wave returns to the sensor main body 10.

[0052] The control device 23 is also equipped with a high-voltage generator 28 and a pulse-width controller 29 for controlling the operation of the solenoid 5. The high-voltage generator 28 is used to convert the power supply voltage to a preset high voltage and then supply it to the solenoid 5, and the pulse-width controller 29 is used to control the number of times and intervals at which voltage is applied to the solenoid 5 based on instructions from the PC 24. That is, the solenoid 5 is connected to the high-voltage generator 28 by an energization switch 30, and the impact switch 8 is connected to the pulse-width controller 29. The pulse-width controller 27 is also connected to the PC 24 and the energization switch 30, so that when the impact switch 8 is turned on, the pulse-width controller 27 controls the energization switch 30 in accordance with instructions from the PC 24 to supply the high voltage output from the high-voltage generator 28 to the solenoid 5 a predetermined number of times at a predetermined interval.

[0053] In the figure, reference numeral 31 denotes a power supply, which in this embodiment is a lithium-ion battery. Also, reference numeral 32 denotes a power switch, and via this power switch 32, the power supply 31 is connected to the preamplifier 25, high-voltage generator 28, and pulse width controller 29. Furthermore, as mentioned above, the A / D converter 27 and pulse width controller are connected to the personal computer 24, which has the function of calculating the embedment depth of the steel structure using a signal from the A / D converter 27, and also controls the operation of the pulse width controller 29 in accordance with the operator's operation, thereby supplying the high voltage output from the high-voltage generator 28 to the solenoid a preset number of times at preset intervals.

[0054] Next, an embodiment of the method for measuring the embedded depth of a steel structure of the present invention using the sensor device 21 of this embodiment configured as described above will be described. When measuring the embedded depth of a steel structure using the above-mentioned sensor device 21, as described above, the sensor 1 is used to generate elastic waves in the sensor main body and transmit these elastic waves to the structure, and the generated elastic waves and reflected waves reflected from the tip or cracks of the steel structure are detected by the sensor main body 10, and the detected elastic waves and reflected waves are converted into predetermined signals and output. The output predetermined signals are then analyzed in the device main body 22 to calculate the embedded depth of the steel structure.

[0055] To explain this measurement method in detail, when measuring the embedment depth of a steel structure using the sensor device 21, the voltage value to be applied to the solenoid, the number of times current is applied to the solenoid, and the interval between current applications are set in advance by operating the control device 23 or the computer 24.

[0056] When actually carrying out the measurement operation, first, the sensor body 10 is brought into contact with the steel structure to be measured, and in this state, the striking switch 8 is turned on.

[0057] Then, the pulse width control unit 29 controls the operation of the solenoid switch 30, and the high voltage output from the high voltage generation unit 28 is supplied to the solenoid a predetermined number of times at predetermined intervals, passing current through the solenoid coil, causing the plunger 6 to jump out of the body of the solenoid with an impact force according to the predetermined voltage value, and the impact hammer 7 strikes the head of the sensor body 10, impacting the sensor body 10.

[0058] This generates an elastic wave in the sensor body 10, and the elastic wave generated in the sensor body 10 is then transmitted to the steel structure being measured because the tip of the sensor body 10 is in contact with the steel structure being measured.

[0059] At the same time, the sensor body 10 detects the elastic waves generated in the sensor body 10 and the reflected waves reflected from locations with characteristics different from those of the steel structure to which the waves were transmitted, such as the tip or cracks of the steel structure, and converts the detected elastic waves and reflected waves into a predetermined electrical signal.

[0060] Next, the elastic waves and reflected waves converted into predetermined electrical signals are output to the device main body 22 via the electric wire 13, where they are subjected to predetermined processing and then analyzed to calculate the embedded depth of the steel structure being measured.

[0061] First, the signals of the elastic waves and reflected waves output from the sensor main body 10 are output to the control device 23 constituting the device main body 22. That is, they are output to a preamplifier constituting the control device 23 and amplified by the preamplifier 25. Then, after that, only the parts necessary for measurement, such as high frequency components, are extracted by a filter 26, and after further A / D conversion by an A / D converter 27, they are output via a USB cable or the like to a personal computer 24 serving as a processing device constituting the device main body 22. Then, using the input signals, the personal computer 24 measures the propagation time of the elastic waves and calculates the embedment depth of the steel structure to be measured.

[0062] As described above, in this embodiment, a solenoid is used to impact the sensor body 10 to generate elastic waves, and the elastic waves are transmitted to the steel structure via the sensor body 10, so there is no individual difference in the impact force and no measurement error occurs.

[0063] Furthermore, the impact force can be adjusted by controlling the driving voltage for driving the solenoid 5, so that the impact force of the hammer can be made extremely large, thereby obtaining high frequency components in the elastic waves and reflected waves, making it possible to measure with high resolution.

[0064] Furthermore, because the method uses a solenoid to deliver impacts, unlike manual impacts, it is possible to deliver impacts repeatedly at regular time intervals, which is also effective in performing averaging to improve the signal-to-noise ratio of weak signals, and it is also possible to preset the number of impacts and the interval (time) between impacts.

[0065] Therefore, according to this embodiment, when performing an impact elastic wave measuring method in which an impact is applied to a structure to generate elastic waves, and the elastic waves and reflected waves are analyzed to measure the embedded depth of a steel structure, it is possible to accurately and reliably measure the embedded depth of the steel structure without being affected by individual differences in impact force. Note that the method of detecting the elastic waves generated in the steel structure and the reflected waves reflected from the tip of the steel structure, converting these detected signals into predetermined signals, and further correcting the embedded depth of the steel structure using the elastic waves converted into these predetermined signals and the time of the reflected waves is already well known as an impact elastic wave measuring method, so a detailed description of the method will be omitted. [Industrial Applicability]

[0066] The present invention is applicable to all methods for measuring embeddedness of steel structures using impact elastic wave measurement methods. [Explanation of symbols]

[0067] 1 sensor 2 Solenoid case 3 Top cover 4 Bottom opening 5 solenoids 6 plungers 7. Impact Hammer 8. Impact Switch 9 Sensor Holder 10 Sensor body 11 Rubber sheet 12 Cable gland 13, 14, 15 Electric wire 13 Signal line 14 Signal line 15 Power line 16 Signal line protection tube 17 Connectors 21 Sensor Device 22 Device body 23 Control device 24 Processing device (PC) 25 Preamp 26 filters 27 A / D converter 28 High-pressure generation section 29 Pulse width control section 30 Solenoid switch 31 Power supply 32 Power switch

Claims

1. A sensor (1) for measuring the embedded depth of a steel structure, a solenoid case (2) having one end opened to form an opening (4); a solenoid (5) accommodated in the solenoid case (2) with a plunger (6) protruding toward the opening (4) of the solenoid case (2); a hammer portion (7) provided at the tip of the plunger (6) of the solenoid (5); a sensor holder (9) attached to the opening (4) side of the solenoid case (2); and a sensor body (10) accommodated in the sensor holder (9) in such a position that the plunger (6) of the solenoid (5) is struck by the hammer portion (7) when the plunger (6) of the solenoid (5) projects from the body of the solenoid (5), The sensor body (10) is brought into contact with the steel structure to be measured, In this state, the solenoid (5) is driven to project the plunger (6) and strike the sensor body (10) with the hammer part (7), thereby applying an impact to the sensor body (10) to generate elastic waves in the sensor body (10) and transmitting the generated elastic waves to the steel structure. A sensor for measuring the embedment depth of a steel structure, characterized in that the generated elastic waves and the reflected waves from the steel structure are detected by a sensor body (10), converted into a predetermined signal, and output.

2. 2. The sensor for measuring the penetration depth of a steel structure according to claim 1, wherein the sensor body (10) is an acceleration sensor.

3. 2. The sensor for measuring the penetration depth of a steel structure according to claim 1, wherein the sensor body (10) is an AE sensor.

4. A sensor device (21) for measuring the embedded depth of a steel structure, for measuring the embedded depth of a steel structure, a solenoid case (2) having an opening at one end thereof; a solenoid (5) accommodated in the solenoid case (2) with a plunger (6) protruding toward the opening (4) of the solenoid case (2); a hammer portion (7) provided at the tip of the plunger (6) of the solenoid (5); a sensor holder (9) attached to the opening (4) side of the solenoid case (2); and a sensor body (10) accommodated in the sensor holder (9) in such a position that the plunger (6) of the solenoid (5) is struck by the hammer portion (7) when the plunger (6) of the solenoid (5) projects from the body of the solenoid (5), a sensor (1) in which a sensor body (10) is brought into contact with a steel structure to be measured, and in that state, a solenoid (5) is driven, a plunger (6) is protruded, and a hammer part (7) strikes the sensor body (10), thereby generating elastic waves in the sensor body (10) and transmitting the generated elastic waves to the steel structure; the sensor body (10) detects the generated elastic waves and the waves reflected from the steel structure, converts them into a predetermined signal, and outputs the signal; and a device main body (22) that controls the operation of the sensor (1) and measures the embedment depth of the steel structure by analyzing a predetermined signal output from the sensor main body (10).

5. The device body (22) is equipped with a control device (23) and a processing device (24), The control device (23) The device is provided with a high voltage generating unit (28) for generating a high voltage to be supplied to the solenoid (5), and a pulse width control unit (29) for controlling the number of times and intervals at which the high voltage generated by the high voltage generating unit (28) is supplied to the solenoid (5), The sensor comprises a preamplifier (25) for amplifying the signals of the elastic waves and the reflected waves output from the sensor body (10), a filter (26) for extracting a portion of the signal amplified by the preamplifier (25) that is necessary for measurement, and an A / D converter (27) for A / D converting the signal of the filter (26) and then outputting it to the processing device (24), The sensor device for measuring the embedment depth of a steel structure as described in claim 4, characterized in that the processing device (24) has the function of calculating the embedment depth of the steel structure being measured by measuring the propagation time of the elastic wave using the output from the A / D converter (27).

6. A method for measuring the embedment depth of a steel structure using the sensor device (21) for measuring the embedment depth of a steel structure according to claim 4, The sensor body (10) is brought into contact with the steel structure to be measured, In this state, the solenoid (5) is driven to project the plunger (6) and strike the sensor body (10) with the hammer part (7), thereby applying an impact to the sensor body (10) to generate elastic waves in the sensor body (10) and transmitting the generated elastic waves to the steel structure. The generated elastic waves and the reflected waves from the steel structure are detected by the sensor body (10) and converted into a predetermined signal. The elastic waves and the reflected waves converted into the predetermined signals are transmitted to the device body (22), A method for measuring the embedment depth of a steel structure, characterized in that the device main body (22) analyzes the received predetermined signal to measure the embedment depth of the steel structure.

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