CN106370109A - Bridge foundation pile steel reinforcement cage length detection apparatus and detection method - Google Patents

Abstract

The invention discloses a bridge foundation pile steel cage length detection device, which includes: a terahertz transceiver device, a terahertz detection device and a computer, the terahertz transceiver device includes a terahertz transmitter and a terahertz detector, the terahertz transmitter The output side of the detector is provided with a first optical mechanism, the first optical mechanism is used to transmit the terahertz wave emitted by the terahertz emitter to the bridge pile to be tested, and the input side of the terahertz detector is provided with a second optical mechanism, The second optical mechanism is used to transmit the terahertz wave reflected by the bridge foundation pile to the terahertz detector, and the terahertz detector converts it into an electrical signal and then transmits it to the terahertz detection device. The bridge foundation pile is scanned in the length direction of the pile, and the terahertz detection device is used to collect the electrical signal output by the terahertz detector and upload it to the computer. The invention is not affected by electromagnetic interference, has stable performance, simple operation, fast detection speed and good accuracy.

Description

A device and method for detecting the length of a bridge foundation pile reinforcement cage

technical field

The invention relates to bridge foundation pile quality detection equipment, in particular to a bridge foundation pile reinforcement cage length detection device and detection method based on terahertz scanning technology.

Background technique

With the vigorous development of my country's engineering construction, foundation piles have been widely used in high-rise buildings, bridges, viaducts, port terminals and other projects, and have become the most important form in my country's engineering construction. The length of the reinforcement cage of the foundation pile is calculated and determined according to the relevant specifications, according to the load, bending moment, soil conditions around the foundation pile, cracking degree of anti-seismic fortification, and whether it belongs to the uplift pile and end-bearing pile. If the length of the reinforcement cage of the foundation pile cannot meet the design requirements, it will constitute a potential safety hazard for the building. Therefore, detecting the length of the reinforcement cage of foundation piles has become a key link in quality management.

In recent years, the detection technology of foundation pile engineering has been continuously updated and improved, and new theories and new methods have emerged continuously. Great progress has also been made in the research on the detection method of the reinforcement cage length in foundation piles. At present, the methods used to detect the length of the reinforcement cage of the foundation pile mainly include the magnetic logging method, the transient electromagnetic method, the charging method in the well, and the like. However, these methods are all affected by electromagnetic interference. In the case of complex and harsh construction environments or human interference, the improvement of their applicability and stability has become the bottleneck of this type of technology. Therefore, it is extremely important and far-reaching to strengthen the research and development of the detection technology for the length of the reinforcement cage of foundation piles.

Contents of the invention

The technical problem to be solved by the present invention is to provide a bridge foundation pile reinforcement cage length detection device and a detection device that is not affected by electromagnetic interference, has stable performance, is simple to operate, has fast detection speed, and has good accuracy. method.

In order to solve the above technical problems, the present invention adopts the following technical solutions.

A bridge foundation pile steel cage length detection device, which includes: a terahertz transceiver device, a terahertz detection device and a computer, the terahertz transceiver device includes a terahertz transmitter and a terahertz detector, the terahertz transmitter The output side of the detector is provided with a first optical mechanism, which is used to transmit the terahertz wave emitted by the terahertz emitter to the bridge pile to be tested, and the input side of the terahertz detector is provided with a second Two optical mechanisms, the second optical mechanism is used to transmit the terahertz wave reflected by the bridge foundation pile to the terahertz detector, and the terahertz wave is converted into an electrical signal by the terahertz detector and then transmitted to the terahertz detection device, so The terahertz transceiver device is used to scan the bridge foundation pile along the length direction of the bridge foundation pile, the terahertz detection device is used to collect the electrical signal output by the terahertz detector and upload it to the computer, and the Generate terahertz images.

Preferably, the terahertz detection device includes a current amplifier, a lock-in amplifier and a data acquisition card that are electrically connected in sequence, wherein: the input end of the current amplifier is electrically connected with the output end of the terahertz detector, and the The current amplifier is used to amplify the current signal output by the terahertz detector and transmit it to the lock-in amplifier; the lock-in amplifier is used to denoise and amplify the current signal output by the current amplifier before transmitting it to the data acquisition card; The above data acquisition card is used to convert the current signal output by the lock-in amplifier into a voltage signal and upload it to the computer.

Preferably, the terahertz detection device further includes a femtosecond laser and a split-two fiber coupler, the laser light emitted by the femtosecond laser is divided into one pump light and one probe light through the split-two fiber coupler, and the The pumping light is loaded on the terahertz emitter, and the detection light is loaded on the terahertz detector; the data acquisition card is also used to output a drive voltage to the terahertz emitter, and the free load generated by the excitation of the pumping light After the carriers are accelerated by the driving voltage, they radiate divergent terahertz waves; the free carriers excited by the detection light move directionally under the action of the terahertz waves reflected by the bridge foundation piles to generate currents. The terahertz detector transmits this current to a current amplifier for amplification.

Preferably, a voltage amplifier is provided between the data acquisition card and the terahertz transmitter, and the voltage amplifier is used to amplify the driving voltage and transmit it to the terahertz transmitter.

Preferably, the output end of the terahertz transmitter is provided with two metal electrodes, and the voltage output by the voltage amplifier is loaded on the two metal electrodes.

Preferably, the powers of the pump light and the probe light are equal, and the length of the optical fiber transmitting the pump light is shorter than the length of the optical fiber transmitting the probe light.

Preferably, the center wavelength of the laser output by the femtosecond laser is 1550nm, the repetition frequency is 50MHz, the average power is 30mw, and the pulse width is 90fs.

Preferably, the first optical mechanism includes a first off-axis parabolic mirror and a first terahertz reflector, the first off-axis parabolic mirror is arranged above the terahertz emitter, and the first terahertz reflector and The terahertz emitters are arranged adjacently, and the terahertz waves emitted by the terahertz emitters are reflected by the first off-axis parabolic mirror as parallel terahertz waves, and then transmitted to the first terahertz reflector, and then passed through the first terahertz reflector Reflected to bridge foundation piles.

Preferably, the second optical mechanism includes a second off-axis parabolic mirror and a second terahertz reflective mirror, the second off-axis parabolic mirror is arranged below the terahertz detector, and the second terahertz reflective mirror and The terahertz detectors are arranged adjacently, and the terahertz wave reflected by the bridge foundation pile is transmitted to the second terahertz reflector, and the terahertz wave is reflected by the second terahertz reflector to the second off-axis parabolic mirror, and then passes through the second terahertz reflector. Reflected by an off-axis parabolic mirror, it converges on a terahertz detector.

Preferably, the first off-axis parabolic mirror, the first terahertz reflecting mirror, the second terahertz reflecting mirror and the second off-axis parabolic mirror are arranged in sequence along the vertical direction.

Preferably, the terahertz transceiver device and the terahertz detection device are connected by a cable, and a bracket for supporting the cable is also provided between the terahertz transceiver device and the terahertz detection device.

A detection method based on the above-mentioned bridge foundation pile steel cage length detection device, the method includes the following steps: step S1, make the terahertz transceiver device scan the bridge foundation pile along the length direction of the bridge foundation pile; step S2, terahertz The terahertz wave emitted by the transmitter is transmitted to the bridge foundation pile to be tested through the first optical mechanism; step S3, the terahertz wave reflected by the bridge foundation pile is transmitted to the terahertz detector through the second optical mechanism, and the terahertz wave is transmitted by the terahertz detector The hertz detector is converted into an electrical signal and then transmitted to the terahertz detection device; step S4, the terahertz detection device collects the electrical signal output by the terahertz detector and uploads it to the computer; step S5, the computer uploads the signal according to the terahertz detection device The electrical signal generates a terahertz image; step S6, by observing the bright and dark areas in the terahertz image to determine the specific position of the reinforcement cage in the bridge foundation pile, and then calculate the actual length of the reinforcement cage in the bridge foundation pile.

Preferably, before performing step S1, a drilling step is also included: drilling the bridge foundation pile along the length direction of the bridge foundation pile, and then laying a PVC pipe in the hole, placing the terahertz transceiver device in the PVC pipe, so that the terahertz The Hertz transceiver is able to move up and down the PVC pipe.

Preferably, the terahertz transceiver device samples the bridge foundation piles multiple times at preset intervals during the scanning process.

Preferably, the distance between two adjacent sampling positions is less than 25 cm.

In the bridge foundation pile steel cage length detection device and detection method disclosed in the present invention, a terahertz transceiver device is used to scan the bridge foundation pile along the length direction of the bridge foundation pile, so that the terahertz wave emitted by the terahertz transmitter passes through the first The optical mechanism is transmitted to the bridge foundation pile to be tested, and the terahertz wave reflected by the bridge foundation pile is transmitted to the terahertz detector through the second optical mechanism, and is converted into an electrical signal by the terahertz detector and then transmitted to the terahertz detection device, using the terahertz detection device to collect the electrical signal output by the terahertz detector and upload it to the computer, wherein, since the terahertz wave has a high transmittance to the concrete and a high reflectivity to the steel bar, so When the terahertz wave scans and images the concrete in the bridge foundation pile, the computer can generate a terahertz image according to the electrical signal uploaded by the terahertz detection device. The specific location, and then calculate the actual length of the reinforcement cage in the bridge foundation pile. The invention makes full use of the terahertz scanning imaging technology, so that the detection device has the advantages of anti-electromagnetic interference, simple operation, fast detection speed and high reliability.

Description of drawings

Fig. 1 is the block diagram of composition of bridge foundation pile reinforcement cage length detecting device of the present invention.

Fig. 2 is a schematic diagram of the detection process of the bridge foundation pile reinforcement cage length detection device of the present invention.

Fig. 3 is a flow chart of the method for detecting the length of the reinforcement cage of the bridge foundation pile of the present invention.

Fig. 4 is the actual picture after inserting the screw on the concrete.

Fig. 5 is a terahertz image obtained after detecting the concrete in Fig. 4 .

detailed description

The present invention will be described in more detail below in conjunction with the accompanying drawings and embodiments.

The present invention discloses a bridge foundation pile reinforcement cage length detection device, as shown in Fig. 1 and Fig. 2, it includes: a terahertz transceiver device 15, a terahertz detection device 20 and a computer 3, the terahertz transceiver device 15 Including a terahertz emitter 12 and a terahertz detector 13, the output side of the terahertz emitter 12 is provided with a first optical mechanism 30, and the first optical mechanism 30 is used to emit the terahertz emitted by the terahertz emitter 12. The Hertzian wave is transmitted to the bridge foundation pile 14 to be tested, and the input side of the terahertz detector 13 is provided with a second optical mechanism 31, and the second optical mechanism 31 is used to transmit the terahertz wave reflected by the bridge foundation pile 14 transmitted to the terahertz detector 13, and converted into an electrical signal by the terahertz detector 13, and then transmitted to the terahertz detection device 20, the terahertz transceiver device 15 is used to connect the bridge along the length direction of the bridge pile 14 The foundation pile 14 is scanned, and the terahertz detection device 20 is used to collect the electrical signal output by the terahertz detector 13 and upload it to the computer 3, and the computer 3 generates a terahertz image.

During the detection process, the above detection device uses the terahertz transceiver device 15 to scan the bridge foundation pile 14 along the length direction of the bridge foundation pile 14, so that the terahertz wave emitted by the terahertz transmitter 12 is transmitted to the bridge pile 14 through the first optical mechanism 30. For the bridge foundation pile 14 to be tested, the terahertz wave reflected by the bridge foundation pile 14 is transmitted to the terahertz detector 13 through the second optical mechanism 31, and is converted into an electrical signal by the terahertz detector 13 and then transmitted to the terahertz wave The detection device 20 uses the terahertz detection device 20 to collect the electrical signal output by the terahertz detector 13 and uploads it to the computer 3, wherein, since the terahertz wave has a relatively high transmittance to concrete, it has a relatively high transmittance to steel bars Therefore, when the terahertz wave scans and images the concrete in the bridge foundation pile, the computer 3 can generate a terahertz image according to the electrical signal uploaded by the terahertz detection device 20, which can be determined by observing the brightness and darkness in the terahertz image The specific position of the reinforcement cage in the bridge foundation pile, and then calculate the actual length of the reinforcement cage in the bridge foundation pile. The invention makes full use of the terahertz scanning imaging technology, so that the detection device has the advantages of anti-electromagnetic interference, simple operation, fast detection speed and high reliability.

Regarding the specific structure of the terahertz detection device 20, the terahertz detection device 20 includes a current amplifier 4, a lock-in amplifier 1, a data acquisition card 2, a femtosecond laser 5, and a one-to-two fiber coupler 7 that are electrically connected in sequence. ,in:

The input end of the current amplifier 4 is electrically connected to the output end of the terahertz detector 13, and the current amplifier 4 is used to amplify the current signal output by the terahertz detector 13 and transmit it to the lock-in amplifier 1;

The lock-in amplifier 1 is used for denoising and secondary amplification of the current signal output by the current amplifier 4 and then transmitting it to the data acquisition card 2;

The data acquisition card 2 is used to convert the current signal output by the lock-in amplifier 1 into a voltage signal and upload it to the computer 3 .

The laser light emitted by the femtosecond laser 5 is divided into one path of pump light and one path of probe light through a one-to-two fiber coupler 7, the pump light is loaded on the terahertz emitter 12, and the probe light is loaded on the terahertz detector 13;

The data acquisition card 2 outputs a drive voltage to the terahertz emitter 12, and the free carriers excited by the pump light are accelerated by the drive voltage to radiate emitted terahertz waves; in addition, the The data acquisition card 2 also outputs a reference signal voltage to the lock-in amplifier 1, the reference signal voltage is output simultaneously with the driving voltage, and the frequency of the two analog voltages is the same.

The free carriers excited by the detection light move directionally under the action of the terahertz wave reflected by the bridge foundation pile 14 to generate a current, and the terahertz detector 13 transmits the current to the current amplifier 4 for amplification.

In this embodiment, in order to increase the acceleration rate of the driving voltage to free carriers, a voltage amplifier 6 is provided between the data acquisition card 2 and the terahertz transmitter 12, and the voltage amplifier 6 is used to convert the driving voltage to After being amplified, it is transmitted to the terahertz transmitter 12. Further, the output end of the terahertz transmitter 12 is provided with two metal electrodes, and the voltage output by the voltage amplifier 6 is loaded on the two metal electrodes.

Regarding the laser light emitted by the femtosecond laser 6, the power of the pump light and the probe light are equal, and the length of the optical fiber transmitting the pump light is shorter than the length of the optical fiber transmitting the probe light. The central wavelength of the laser output from the femtosecond laser 5 is 1550nm, the repetition frequency is 50MHz, the average power is 30mw, and the pulse width is 90fs. In addition, the volume of the femtosecond laser 5 is 20.3cm×12.7cm4.3cm.

In this embodiment, the first optical mechanism 30 includes a first off-axis parabolic mirror 10 and a first terahertz reflector 8, the first off-axis parabolic mirror 10 is arranged above the terahertz emitter 12, the The first terahertz reflector 8 is adjacent to the terahertz emitter 12, and the terahertz wave emitted by the terahertz emitter 12 is reflected by the first off-axis parabolic mirror 10 as a parallel terahertz wave and then transmitted to the first terahertz wave. The reflector 8 is then reflected to the bridge foundation pile 14 through the first terahertz reflector 8 .

Similarly, the second optical mechanism 31 includes a second off-axis parabolic mirror 11 and a second terahertz reflector 9, the second off-axis parabolic mirror 11 is arranged below the terahertz detector 13, and the second The terahertz reflector 9 is set adjacent to the terahertz detector 13, and the terahertz wave reflected by the bridge foundation pile 14 is transmitted to the second terahertz reflector 9, and the terahertz wave is reflected by the second terahertz reflector 9 to the second terahertz reflector 9. The two off-axis parabolic mirrors 11 converge on the terahertz detector 13 after being reflected by the second off-axis parabolic mirror 11 .

Based on the optical mechanism of the above two structures, the terahertz transceiver device 15 can be miniaturized, and the specific structure is: the first off-axis parabolic mirror 10, the first terahertz mirror 8, the second terahertz mirror 9 and the first Two off-axis parabolic mirrors 11 are arranged in sequence along the vertical direction. This structure enables the detection part of the terahertz transceiver device 15 to be located on the same side, and the terahertz transceiver device 15 can scan the bridge foundation pile 14 while rising or falling.

As a preferred manner, the terahertz transceiver device 15 and the terahertz detection device 20 are connected by a cable, and a bracket for supporting the cable is also provided between the terahertz transceiver device 15 and the terahertz detection device 20 17.

In this embodiment, the terahertz emitter 12 and the terahertz detector 13 use a photoconductive antenna, but in other embodiments of the present invention, other methods of radiating terahertz and detecting terahertz can also be used, such as using light The rectification effect radiation terahertz method and the free space electro-optic sampling method to detect terahertz.

Regarding some preferred parameters of the product, the volume of the terahertz detection device 20 is less than 50cm×30cm×30cm, the weight is less than 10kg, and the power consumption is less than 200W. The size of the terahertz transceiver 15 is less than 6cm×6cm×10cm, and the weight is less than 500g.

On the basis of the above-mentioned bridge foundation pile reinforcement cage length detection device, the present invention also discloses a detection method, as shown in Figure 1 and Figure 3, the method includes the following steps:

Step S1, make the terahertz transceiver device 15 scan the bridge foundation pile 14 along the length direction of the bridge foundation pile 14;

Step S2, the terahertz wave emitted by the terahertz transmitter 12 is transmitted to the bridge foundation pile 14 to be tested through the first optical mechanism 30;

Step S3, the terahertz wave reflected by the bridge foundation pile 14 is transmitted to the terahertz detector 13 through the second optical mechanism 31, and is converted into an electrical signal by the terahertz detector 13 and then transmitted to the terahertz detection device 20;

Step S4, the terahertz detection device 20 collects the electrical signal output by the terahertz detector 13 and uploads it to the computer 3;

Step S5, the computer 3 generates a terahertz image according to the electrical signal uploaded by the terahertz detection device 20;

Step S6, by observing the bright and dark areas in the terahertz image to determine the specific position of the reinforcement cage in the bridge foundation pile, and then calculate the actual length of the reinforcement cage in the bridge foundation pile.

In order to facilitate detection, a drilling step is also included before performing step S1: drilling the bridge foundation pile 14 along the length direction of the bridge foundation pile 14, and then inserting the PVC pipe 16 in the hole, and placing the terahertz transceiver device 15 on the PVC pipe 16, so that the terahertz transceiver 15 can move up and down along the PVC pipe 16.

In order to ensure detection efficiency and detection accuracy, sampling may be performed at reasonable intervals, specifically, the terahertz transceiver 15 samples the bridge foundation piles 14 multiple times at preset intervals during the scanning process. Preferably, the distance between two adjacent sampling positions is less than 25 cm. During the detection process, the detection depth of the terahertz transceiver device 15 is greater than 50m, the detection accuracy is less than 5mm, and the single measurement time is less than 5s.

In order to further illustrate the detection effect of the present invention, in conjunction with shown in Fig. 4 and Fig. 5, get a piece of concrete as the bridge foundation pile, drill two holes in the concrete with an electric drill, then place the No. 1 screw 21 and the No. 22 are inserted into the holes respectively, and the terahertz transceiver device is used to perform terahertz scanning imaging on the side of the concrete to detect the depth of the No. 1 screw 21 and No. 2 screw 22 inserted into the concrete, and then simulate the detection of the bridge foundation pile reinforcement cage. In Figure 4, there are two screws representing the reinforcement cage. The upper left screw is the No. 1 screw 21, and the lower right screw is the No. 2 screw 22. The distances between the two screws and the left edge are different, and the No. 1 screw 21 is closer to the left edge. , the No. 2 screw 22 is far away from the left edge, and the terahertz transceiver device scans from the left side to obtain a terahertz image. Figure 5 is the scanned terahertz image. In Figure 5, there are two relatively bright strip-shaped areas. The bright strip-shaped area on the left is the No. 1 screw terahertz image 23, and the bright strip-shaped area on the right is No. 2. Screw terahertz image 24. From Figure 5, it can be clearly seen that the depth of the two screws inserted into the concrete is the same, about three quarters of the total depth. Since No. 1 screw 21 is closer to the left edge than No. 2 screw 22, that is, closer to the reflective terahertz transceiver than No. 2 screw 22, the terahertz image of No. 1 screw corresponding to No. 1 screw 21 is brighter.

Compared with the prior art, the present invention adopts the terahertz scanning imaging technology, which has the advantages of anti-electromagnetic interference, simple operation, fast detection speed and high reliability. At the same time, the terahertz wave adopted in the present invention has a very high resolution, and can detect the length of the reinforcement cage on the order of millimeters. In addition, the present invention adopts a non-contact non-destructive detection method, which can protect the detected object very well. Thirdly, the terahertz detection device adopted in the present invention is small in size, low in cost, easy to carry, easy to popularize, and has very broad application prospects.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. All modifications, equivalent replacements or improvements made within the technical scope of the present invention shall be included in the protection scope of the present invention.

Claims (15)

1. a kind of Bridge Piles determination of the length of a steel reinforced cage device is it is characterised in that include: Terahertz R-T unit (15), too Hertz detection means (20) and computer (3), described Terahertz R-T unit (15) includes terahertz transmitter (12) and too Hertz detector (13), the outlet side of described terahertz transmitter (12) is provided with the first optical facilities (30), described first optics Mechanism (30) is used for transmitting the THz wave of terahertz transmitter (12) outgoing to Bridge Piles (14) to be measured, described terahertz Hereby the input side of detector (13) is provided with the second optical facilities (31), and described second optical facilities (31) are used for will be through bridge base The THz wave that stake (14) is reflected transmits to terahertz detector (13), and is converted to electricity by described terahertz detector (13) Transmit after signal to Terahertz detection means (20), described Terahertz R-T unit (15) is used for the length along Bridge Piles (14) Direction is scanned to this Bridge Piles (14), and described Terahertz detection means (20) is used for gathering terahertz detector (13) defeated The signal of telecommunication that goes out simultaneously is uploaded to computer (3), generates Terahertz image by described computer (3).

2. Bridge Piles determination of the length of a steel reinforced cage device as claimed in claim 1 is it is characterised in that the detection of described Terahertz fills Put (20) and include the current amplifier (4) being electrically connected with successively, lock-in amplifier (1) data capture card (2), wherein:

The input of described current amplifier (4) is electrically connected with the outfan of terahertz detector (13), described Current amplifier The current signal that device (4) is used for exporting terahertz detector (13) transmits to lock-in amplifier (1) after amplifying；

The current signal that described lock-in amplifier (1) is used for that current amplifier (4) is exported passes after carrying out denoising and two grades of amplifications Transport to data collecting card (2)；

The current signal that described data collecting card (2) is used for exporting lock-in amplifier (1) is converted to and is uploaded to after voltage signal Computer (3).

3. Bridge Piles determination of the length of a steel reinforced cage device as claimed in claim 2 is it is characterised in that the detection of described Terahertz fills Put (20) and also include femto-second laser (5) and one-to-two fiber coupler (7), the laser of described femto-second laser (5) outgoing It is divided into a road pump light through one-to-two fiber coupler (7) and a road detects light, described pump light loads on terahertz sources Device (12), described detection light loads on terahertz detector (13)；

Described data collecting card (2) is additionally operable to export a road driving voltage to terahertz transmitter (12), is swashed by described pump light Send out the free carrier producing after described driving voltage accelerates, give off the THz wave dissipating；

The free carrier of generation is excited to orient under the THz wave effect that Bridge Piles (14) are reflected by the described light that detects Move and produce electric current, this electricity is streamed to current amplifier (4) and is amplified by described terahertz detector (13).

4. Bridge Piles determination of the length of a steel reinforced cage device as claimed in claim 3 is it is characterised in that described data collecting card (2) it is provided with a voltage amplifier (6) and terahertz transmitter (12) between, described voltage amplifier (6) is used for described driving Transmit after voltage amplification to terahertz transmitter (12).

5. Bridge Piles determination of the length of a steel reinforced cage device as claimed in claim 4 is it is characterised in that described terahertz transmitter (12) outfan is provided with two metal electrodes, and the voltage-drop loading that described voltage amplifier (6) exports is in this two metal electrodes On.

6. Bridge Piles determination of the length of a steel reinforced cage device as claimed in claim 3 is it is characterised in that described pump light and detection The power of light is equal, and the fiber lengths of transmission pump light are shorter than the fiber lengths that transmission detects light.

7. Bridge Piles determination of the length of a steel reinforced cage device as claimed in claim 3 is it is characterised in that described femto-second laser (5) centre wavelength of output laser is 1550nm, and repetition rate is 50mhz, and mean power is 30mw, and pulse width is 90fs.

8. Bridge Piles determination of the length of a steel reinforced cage device as claimed in claim 1 is it is characterised in that described first optical facilities (30) the first off axis paraboloidal mirror (10) and the first Terahertz reflecting mirror (8), described first off axis paraboloidal mirror (10) are included Above terahertz transmitter (12), described first Terahertz reflecting mirror (8) is disposed adjacent with terahertz transmitter (12), institute The THz wave stating terahertz transmitter (12) outgoing is after the first off axis paraboloidal mirror (10) is reflected into parallel THz wave Transmit to the first Terahertz reflecting mirror (8), then reflex to Bridge Piles (14) through the first Terahertz reflecting mirror (8).

9. Bridge Piles determination of the length of a steel reinforced cage device as claimed in claim 8 is it is characterised in that described second optical facilities (31) the second off axis paraboloidal mirror (11) and the second Terahertz reflecting mirror (9), described second off axis paraboloidal mirror (11) are included Below terahertz detector (13), described second Terahertz reflecting mirror (9) is disposed adjacent with terahertz detector (13), warp Cross the THz wave that Bridge Piles (14) reflect to transmit to the second Terahertz reflecting mirror (9), this THz wave is through the second terahertz Hereby reflecting mirror (9) reflexes to the second off axis paraboloidal mirror (11), then converges in after the second off axis paraboloidal mirror (11) reflection On terahertz detector (13).

10. Bridge Piles determination of the length of a steel reinforced cage device as claimed in claim 9 is it is characterised in that described first throws from axle Object plane mirror (10), the first Terahertz reflecting mirror (8), the second Terahertz reflecting mirror (9) and the second off axis paraboloidal mirror (11) edge are perpendicular Nogata is to setting gradually.

11. Bridge Piles determination of the length of a steel reinforced cage devices as claimed in claim 1 are it is characterised in that described Terahertz is received and dispatched Connected by cable between device (15) and Terahertz detection means (20), described Terahertz R-T unit (15) and Terahertz are examined Survey the support (17) being additionally provided between device (20) for supporting cable.

The detection method of Bridge Piles determination of the length of a steel reinforced cage device described in a kind of 12. any one based on claim 1 to 11, its It is characterised by, the method comprises the steps:

Step s1, makes Terahertz R-T unit (15) along the length direction of Bridge Piles (14), this Bridge Piles (14) be swept Retouch；

Step s2, the THz wave of terahertz transmitter (12) outgoing transmits to bridge to be measured through the first optical facilities (30) Foundation pile (14)；

Step s3, the THz wave being reflected by Bridge Piles (14) transmits to terahertz detector through the second optical facilities (31) (13) be converted to, and by described terahertz detector (13) and transmit after the signal of telecommunication to Terahertz detection means (20)；

Step s4, the signal of telecommunication that described Terahertz detection means (20) collection terahertz detector (13) exports simultaneously is uploaded to calculating Machine (3)；

Step s5, described computer (3) generates Terahertz image according to the signal of telecommunication that Terahertz detection means (20) uploads；

Step s6, determines the particular location of steel reinforcement cage in Bridge Piles, enters by observing the bright dark areas in Terahertz image And calculate the physical length of steel reinforcement cage in Bridge Piles.

13. detection methods as claimed in claim 12 are it is characterised in that also include punch out step: edge before execution step s1 The length direction of Bridge Piles (14) is holed to this Bridge Piles (14), and lower pvc pipe (16) in hole, Terahertz is received and dispatched afterwards Device (15) is placed in pvc pipe (16), to make Terahertz R-T unit (15) can move up and down along pvc pipe (16).

14. detection methods as claimed in claim 12 are it is characterised in that described Terahertz R-T unit (15) is in scanning process In by preset pitch, multiple repairing weld is carried out to Bridge Piles (14).

15. detection methods as claimed in claim 15 are it is characterised in that being smaller than between two neighboring sampling location 25cm.