CN112325764A - Wireless monitoring method for surface strain of secondary lining structure of railway tunnel - Google Patents
Wireless monitoring method for surface strain of secondary lining structure of railway tunnel Download PDFInfo
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- CN112325764A CN112325764A CN202011231147.3A CN202011231147A CN112325764A CN 112325764 A CN112325764 A CN 112325764A CN 202011231147 A CN202011231147 A CN 202011231147A CN 112325764 A CN112325764 A CN 112325764A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
- G01B7/18—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in resistance
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
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Abstract
The invention discloses a wireless monitoring method for surface strain of a secondary lining structure of a railway tunnel, which comprises the following steps: step one, two completely same resistance type strain gauges are connected in series and connected with two fixed resistors connected in series in a ring-forming mode to form a Wheatstone bridge; and a lead is led out from each of the four connecting positions; and step two, connecting a voltage signal input port and a grounding end of the RFID label with connection points between the resistance type strain and the fixed resistors respectively. Tightly attaching one of the resistance-type strain gauges to the surface of a to-be-tested strain part of the secondary lining structure, wherein the resistance-type strain gauge is used for deforming along with the deformation of the secondary lining structure; and step five, enabling the RFID reader to enter the radio frequency identification range of the RFID label. According to the method, a large number of long data lines do not need to be connected to the strain gauge, so that the workload can be reduced, and meanwhile, the data acquisition efficiency is improved.
Description
Technical Field
The invention belongs to the technical field of monitoring of a railway tunnel secondary lining structure, and particularly relates to a wireless monitoring method for surface strain of a railway tunnel secondary lining structure.
Background
In the tunnel construction process, in order to analyze the stress condition of the secondary lining structure and provide a reference basis for the dynamic design of primary support, the stress of the steel arch frame needs to be monitored.
The currently generally adopted stress monitoring method for the secondary lining structure is as follows: (1) a pressure box is buried in the secondary lining structure, then a data line is led out of the tunnel, and an acquisition instrument is connected to acquire data. (2) And embedding a strain gauge on the surface of the secondary lining structure, and then connecting an acquisition instrument through a data line to acquire data.
The method needs each pressure box and strain gauge to be connected with a data line, then the data line is led out to each data acquisition box, a large number of data lines are usually adopted in a tunnel with several kilometers, the workload is huge, the acquisition work is complicated, and the working efficiency is low.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a wireless monitoring method for surface strain of a secondary lining structure of a railway tunnel, aiming at the defects of the prior art, by which a large number of long data lines do not need to be connected to a strain gauge, the workload can be reduced, and the efficiency of data acquisition can be improved.
In order to solve the technical problem, the invention adopts the technical scheme that the wireless monitoring method for the surface strain of the secondary lining structure of the railway tunnel comprises the following steps:
step one, two completely same resistance type strain gauges are connected in series and connected with two fixed resistors connected in series in a ring-forming mode to form a Wheatstone bridge; and a lead is led out from each of the four connecting positions; the resistance values of the two resistance type strain gauges and the two fixed resistors are the same;
step two, connecting a voltage signal input port and a grounding end of the RFID label with connection points between the resistance type strain and the fixed resistors respectively; two ends of a power supply of the RFID tag are respectively connected with connecting points between the two resistance type strain gauges and between the two fixed resistors;
tightly attaching one of the resistance-type strain gauges to the surface of a to-be-tested strain part of the secondary lining structure, wherein the resistance-type strain gauge is used for deforming along with the deformation of the secondary lining structure;
the other resistance type strain gauge and the two fixed resistors are fixed on the periphery of the strain position to be measured; the RFID tag is used for collecting a voltage difference value between two connection points between the resistance type strain and the fixed resistor and supplying power to the Wheatstone bridge;
step four, pouring a secondary lining, wherein the Wheatstone bridge and the RFID tag are both poured in the secondary lining;
connecting the RFID reader with a data acquisition processor; enabling the RFID reader to enter the radio frequency identification range of the RFID label;
the RFID reader transmits a signal to the RFID tag to activate the RFID tag; receiving a radio frequency digital signal sent by the RFID label, restoring the digital signal into a voltage difference signal and transmitting the voltage difference signal;
step six, the data acquisition processor receives the voltage difference signal transmitted in the step five, according to the following formula,
obtaining the strain of the resistance-type strain gauge attached to the strain position to be measured, namely the strain of the strain position to be measured of the secondary lining structure;
wherein, the delta U is the voltage difference between the two connection points;
e is the resistance ratio of the resistance-type strain gauge which is not attached to the strain position to be measured and the fixed resistor connected with the resistance-type strain gauge;
delta R is the resistance value change value of the resistance type strain gauge attached to the strain position to be measured;
k is the sensitivity of the resistance type strain gauge attached to the strain position to be measured;
epsilon is the strain of the resistance-type strain gauge attached to the strain position to be measured;
R1is the first of a resistance-type strain gage attached to a strain position to be measuredA starting resistance value.
Further, the two resistive strain gages are identical in shape.
Further, the RFID reader and the data acquisition processor
Are all arranged on the tunnel detection vehicle.
Further, the power supply is a button cell.
Further, the RFID tag also comprises a tag radio frequency chip and a tag antenna;
the tag radio frequency chip is connected with the voltage signal input port, the grounding end, the tag antenna and the button cell;
the tag radio frequency chip is used for receiving the voltage difference signal, converting the voltage difference signal into a radio frequency digital signal and sending the radio frequency digital signal to the tag antenna.
Furthermore, the RFID reader comprises a reader radio frequency chip reader antenna, a data processing module and a USB interface, wherein the reader antenna and the data processing module are both connected with the reader radio frequency chip, and the USB interface is connected with the data processing module;
the reader radio frequency chip receives and transmits the radio frequency digital signal sent by the tag antenna through the reader antenna; the reader radio frequency chip also sends information to the tag antenna through the reader antenna;
the data processing module is used for receiving a radio frequency digital signal sent by a radio frequency chip of the reader and converting the radio frequency digital signal into a voltage difference signal;
and the USB interface is used for receiving the voltage difference signal sent by the data processing module and transmitting the voltage difference signal to the data acquisition and processing instrument.
Furthermore, the two fixed resistors and the resistance type strain gauge which is not attached to the strain position to be measured are packaged in a protective film.
The invention has the following advantages: 1. the RFID tag transmits radio frequency signals to transmit data, a large number of data wires are not needed, the work of laying a large number of wires is reduced, and the data acquisition speed is increased.
2. The resistance-type strain gauges are positioned in a Wheatstone bridge, and one resistance-type strain gauge is attached to a to-be-measured strain part of the secondary lining structure and deforms along with the deformation of the structure; and the RFID label is used for collecting the voltage difference value of two ends of the Wheatstone bridge, so that the sensitivity is high and the measured value is accurate.
3. The other resistance-type strain gauge in the Wheatstone bridge is arranged at the periphery of the strain position to be measured, so that the two resistance-type strain gauges are ensured to be positioned in the same temperature field, the resistance changes of the two resistance-type strain gauges caused by the temperature change are the same, and the error caused by the temperature change to strain measurement can be counteracted.
And 4, the RFID reader and the data acquisition processor can be arranged on the tunnel detection vehicle, so that the data acquisition speed is increased.
5. The RFID reader can simultaneously receive data of a plurality of RFID labels, and receives data transmission of the RFID labels in a radio frequency range along with the forward movement of the tunnel detection vehicle, so that the required equipment is few, and the transmission efficiency is high.
Drawings
FIG. 1 is a schematic diagram of wireless monitoring of tunnel primary support arch stress based on RFID technology;
FIG. 2 is a schematic diagram of a Wheatstone bridge;
FIG. 3 is a schematic view of an RFID tag;
FIG. 4 is a schematic diagram of an RFID reader;
FIG. 5 is a schematic diagram of a Wheatstone bridge;
wherein: 1. a Wheatstone bridge; an RFID tag; 3. a secondary lining structure; 4. positioning a button cell; 5, RFID reader; 6. a data acquisition processor; 7. a first resistive strain gage; 8. a second resistive strain gage; 9. a first fixed resistor; 10. a second fixed resistor; 11. a first connection point; 12. a second connection point; 13. a voltage signal input port; 14. a ground terminal; 15. a tag radio frequency chip; 16. a tag antenna; 17. a button cell; 18. a positive electrode; 19. a negative electrode; 20. a reader radio frequency chip; 21. a reader antenna; 22. a data processing module; a USB interface; 24. a third connection point; 25. a fourth connection point.
Detailed Description
The invention discloses a wireless monitoring method for surface strain of a railway tunnel secondary lining structure, which comprises the following steps:
step one, two completely same resistance type strain gauges are connected in series and connected with two fixed resistors connected in series in a ring-forming mode to form a Wheatstone bridge; and a lead is led out from each of the four connecting positions; the two resistance type strain gauges and the two fixed resistors have the same resistance value, and the same shape and specification. The two fixed resistors are a first fixed resistor 9 and a second fixed resistor 10, respectively. As shown in fig. 2.
Step two, connecting a voltage signal input port 13 and a grounding terminal 14 of the RFID tag 2 with connection points between the resistance type strain and the fixed resistors respectively; two ends of a power supply of the RFID label 2 are respectively connected with connecting points between the two resistance type strain gauges and between the two fixed resistors;
and thirdly, tightly attaching one of the resistance-type strain gauges to the surface of the strain part to be measured of the secondary lining structure 3, wherein the resistance-type strain gauge is used for deforming along with the deformation of the secondary lining structure 3.
The other resistance type strain gauge and the two fixed resistors are fixed on the periphery of the strain position to be measured, and the distance from the strain position to be measured is 1-2 cm. The fixed RFID tag 2 is used for acquiring a voltage difference value between two connection points between the resistance type strain and the fixed resistor and supplying power to the Wheatstone bridge; the power source is a button cell 17.
The two identical resistive strain gauges are respectively a first resistive strain gauge 7 and a second resistive strain gauge 8. Attached to the secondary lining structure 3 at the location of the strain to be measured is a first resistive strain gauge 7.
And step four, pouring a secondary lining, wherein the Wheatstone bridge 1 and the RFID tag 2 are both poured in the secondary lining. As shown in fig. 1.
Connecting the RFID reader 5 with the data acquisition processor 6; the RFID reader 5 is brought into the radio frequency identification range of the RFID tag 2.
The RFID reader 5 transmits a signal to the RFID tag 2 to activate the RFID tag 2; and receiving the radio frequency digital signal sent by the RFID label 2, restoring the digital signal into a voltage difference signal and transmitting the voltage difference signal.
Step six, the data acquisition processor 6 receives the voltage difference signal transmitted in the step five,according to the following formula,
the strain of the first resistance type strain gauge 7 is obtained, namely the strain of the strain part to be measured of the secondary lining structure 3;
wherein, the delta U is the voltage difference between the two connection points;
e is the resistance ratio of the resistance-type strain gauge which is not attached to the strain position to be measured and the fixed resistor connected with the resistance-type strain gauge;
delta R is the resistance value change value of the resistance type strain gauge attached to the strain position to be measured;
k is the sensitivity of the resistance type strain gauge attached to the strain position to be measured;
epsilon is the strain of the resistance-type strain gauge attached to the strain position to be measured;
R1the initial resistance value of the resistive strain gauge attached to the strain site to be measured.
During the use, RFID reads ware 5) and data acquisition processor 6) all sets up on the tunnel detects the car.
As shown in fig. 3, the RFID tag 2 further includes a tag rf chip 15 and a tag antenna 16; the tag radio frequency chip 15 is connected with the voltage signal input port 13, the grounding terminal 14, the tag antenna 16 and the button cell 17; the tag radio frequency chip 15 is configured to receive the voltage difference signal, convert the voltage difference signal into a radio frequency digital signal, and send the radio frequency digital signal to the tag antenna 16.
As shown in fig. 4, the RFID reader 5 includes a reader rf chip (20), a reader antenna 21, a data processing module 22, and a USB interface 23, where the reader antenna 21 and the data processing module 22 are both connected to the reader rf chip 20, and the USB interface 23 is connected to the data processing module 22. The reader radio frequency chip 20 receives and transmits the radio frequency digital signal sent by the tag antenna 16 through the reader antenna 21; the reader rf chip 20 also sends information to the tag antenna 16 via the reader antenna 21.
The data processing module 22 is configured to receive a radio frequency digital signal sent by the reader radio frequency chip 20, and convert the radio frequency digital signal into a voltage difference signal. And the USB interface 23 is configured to receive the voltage difference signal sent by the data processing module 22, and transmit the voltage difference signal to the data acquisition and processing instrument 6.
The two fixed resistors and the resistance type strain gauge which is not attached to the strain position to be measured are packaged in a protective film. The fixed resistors and the resistance type strain gauges are protected, and meanwhile, the resistance type strain gauges which are not attached to the strain position to be tested are prevented from being directly contacted with the secondary lining structure 3.
The principle of the wheatstone bridge 1 for measuring strain is described above with reference to fig. 5.
a. A common circuit for measuring strain is a wheatstone bridge. A wheatstone bridge is a bridge circuit consisting of four resistors, which are respectively called the legs of the bridge. In the bridge there are two fixed resistors, R respectively2、R4(ii) a In addition R1、R3Two identical resistance strain gauges. R1、R2And R3、R4A voltmeter is connected between the two. The two ends of the whole bridge are connected with a voltage source. When the bridge balances R1:R2=R3:R4When the voltage is measured, the voltage at two ends of the voltmeter is 0 according to the voltage division principle. When R is1When the voltage changes, the voltage between the two points A, B in the graph changes, the change of the resistance of the strain gauge can be known by collecting the change of the voltage, and the strain at the position can be deduced to realize the purpose of measurement.
b. Factors that affect the resistance of a strain gage are temperature in addition to strain. R1R of adjacent arm3As a temperature compensation plate with R1Placed in the same temperature field without participating in the strain measurement. In this way, the effect of temperature on the bridge measurement is eliminated.
c. When the bridge is balanced, R1:R2=R3:R4In the circuit, the potential difference between the two points AB is 0. If at this time, the strain gauge R1Increase the resistance Δ R, i.e. R, by a small amount1=R0+ Δ R, thenThe bridge is out of balance, and a certain potential difference U exists between two points AB in the circuitAB. If the voltage of the bridge power supply is U0According to the voltage division principle of the series resistors and taking the point C in the circuit as a zero potential reference point, the output voltage of the bridge is as follows:
make the bridge ratioAccording to the condition of the balance of the bridge,and when Δ R is much less than R0In the meantime, the tiny items in the denominator are omitted,comprises the following steps:
d. as shown in equation 2, the voltage difference U between the two arms of the Wheatstone bridgeABAnd the resistance value change delta R of the resistance strain gauge is in a linear relation. Accordingly, U can be obtained from the measurementABAnd calculating the Delta R. And then according to the known relation between the sensitivity K of the resistance strain gauge and the strain epsilon:and calculating epsilon.
Claims (7)
1. A wireless monitoring method for surface strain of a secondary lining structure of a railway tunnel is characterized by comprising the following steps:
step one, two completely same resistance type strain gauges are connected in series and connected with two fixed resistors connected in series in a ring-forming mode to form a Wheatstone bridge; and a lead is led out from each of the four connecting positions; the resistance values of the two resistance type strain gauges and the two fixed resistors are the same;
step two, a voltage signal input port (13) and a grounding terminal (14) of the RFID label (2) are respectively connected with the connection points between the resistance type strain and the fixed resistors; two ends of a power supply of the RFID label (2) are respectively connected with connecting points between the two resistance type strain gauges and between the two fixed resistors;
tightly attaching one of the resistance-type strain gauges to the surface of a to-be-tested strain part of the secondary lining structure (3), wherein the resistance-type strain gauge is used for deforming along with the deformation of the secondary lining structure (3);
the other resistance type strain gauge and the two fixed resistors are fixed on the periphery of the strain position to be measured; the RFID tag (2) is fixed, and the RFID tag (2) is used for collecting a voltage difference value between two connection points between the resistance type strain and the fixed resistor and supplying power to the Wheatstone bridge;
pouring a secondary lining, wherein the Wheatstone bridge (1) and the RFID tag (2) are both poured in the secondary lining;
connecting the RFID reader (5) with the data acquisition processor (6); -bringing an RFID reader (5) into a radio frequency identification range of the RFID tag (2);
the RFID reader (5) transmits a signal to the RFID tag (2) to activate the RFID tag (2); receiving the radio frequency digital signal sent by the RFID label (2), restoring the digital signal into a voltage difference signal and transmitting the voltage difference signal;
step six, the data acquisition processor (6) receives the voltage difference signal transmitted in the step five, according to the following formula,
obtaining the strain of the resistance-type strain gauge attached to the strain position to be measured, namely the strain of the strain position to be measured of the secondary lining structure (3);
wherein, the delta U is the voltage difference between the two connection points;
e is the resistance ratio of the resistance-type strain gauge which is not attached to the strain position to be measured and the fixed resistor connected with the resistance-type strain gauge;
delta R is the resistance value change value of the resistance type strain gauge attached to the strain position to be measured;
k is the sensitivity of the resistance type strain gauge attached to the strain position to be measured;
epsilon is the strain of the resistance-type strain gauge attached to the strain position to be measured;
R1the initial resistance value of the resistive strain gauge attached to the strain site to be measured.
2. The method for wirelessly monitoring the surface strain of the railway tunnel secondary lining structure as claimed in claim 1, wherein the two resistive strain gauges have the same shape.
3. The wireless monitoring method for the surface strain of the secondary lining structure of the railway tunnel as claimed in claim 2, wherein the RFID reader (5) and the data acquisition processor (6)
Are all arranged on the tunnel detection vehicle.
4. The wireless monitoring method for strain of the tunnel primary support secondary lining structure based on the RFID technology as claimed in claim 3, wherein the power source is a button cell (17).
5. The wireless monitoring method for the strain of the tunnel primary support secondary lining structure based on the RFID technology is characterized in that the RFID tag (2) further comprises a tag radio frequency chip (15) and a tag antenna (16);
the tag radio frequency chip (15) is connected with the voltage signal input port (13), the grounding end (14), the tag antenna (16) and the button cell (17);
the tag radio frequency chip (15) is used for receiving the voltage difference signal, converting the voltage difference signal into a radio frequency digital signal and sending the radio frequency digital signal to the tag antenna (16).
6. The wireless monitoring method for the strain of the tunnel primary support secondary lining structure based on the RFID technology is characterized in that the RFID reader (5) comprises a reader radio frequency chip (20), a reader antenna (21), a data processing module (22) and a USB interface (23), wherein the reader antenna (21) and the data processing module (22) are both connected with the reader radio frequency chip (20), and the USB interface (23) is connected with the data processing module (22);
the reader radio frequency chip (20) receives and transmits the radio frequency digital signal sent by the tag antenna (16) through the reader antenna (21); the reader radio frequency chip (20) also sends information to the tag antenna (16) through the reader antenna (21);
the data processing module (22) is used for receiving a radio frequency digital signal sent by the reader radio frequency chip (20) and converting the radio frequency digital signal into a voltage difference signal;
and the USB interface (23) is used for receiving the voltage difference signal sent by the data processing module (22) and transmitting the voltage difference signal to the data acquisition processor (6).
7. The wireless monitoring method for the strain of the tunnel primary support secondary lining structure based on the RFID technology as claimed in claim 6, wherein the two fixed resistors and the resistive strain gauge which is not attached to the strain position to be measured are packaged in a protective film.
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CN211230555U (en) * | 2019-12-17 | 2020-08-11 | 招商局重庆交通科研设计院有限公司 | Multi-scale monitoring and early warning system for operation safety of highway tunnel |
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CN105973302A (en) * | 2016-06-07 | 2016-09-28 | 上海建桥学院 | Vehicle-mounted RFID environment monitoring system and method |
CN206514804U (en) * | 2016-12-22 | 2017-09-22 | 陕西电器研究所 | A kind of label type wireless senser |
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