CN101750035B - Nondestructive examination method for anchored bolt length and examination device thereof - Google Patents

Abstract

The lossless detection method and its detection device of anchoring rod length, are related to non-destructive testing. The present invention solves the problem of that existing detection method process is complicated, instrument is heavy and is not suitable for on-site test. Step of the invention: 1) taking free bolt length identical with tested anchor pole is L 0,Strobe pulse tranmitting frequency is 2.25MHz,Analyze first edge echo of free bolt; 2) fft analysis is used to each separation wave packet of first edge echo of free bolt,Obtain crest frequency and its arrival time of each separation wave packet of edge echo; 3) anchoring rod is detected by the transmitting pulse frequency of step 1) setting,First edge echo of anchoring rod is chosen,It is handled according to step 2) and obtains each separation wave packet crest frequency and its arrival time of anchoring rod edge echo; 4) the selection the smallest data f 1 of frequency value difference and f 2,With corresponding arrival time T 1 and T 2; 5) the length L of anchoring rod is calculated according to the following formula.

Description

The lossless detection method of anchoring rod length and pick-up unit thereof

Technical field

The present invention relates to Non-Destructive Testing, particularly a kind of method and employed pick-up unit thereof that utilizes supersonic guide-wave Non-Destructive Testing anchoring rod length.

Background technology

Anchor pole is widely used in the reinforcing and supporting of underground passage and side slope country rock as an important component part of support system.But the working environment very severe of anchor pole often receives the influence of the underground water corrosion of being rich in various mineral matters and adjacent domain mining disturbance etc., and these effects often cause the fracture of anchoring rod.In addition, owing to lack simple and effective detection means, construction party is used inferior materials and turned out substandard goods for seeking wrongful interests in work progress, shortens rock-bolt length, thereby makes the anchor pole loading strength not reach design standards, causes potential accident potential to Geotechnical Engineering.The anchoring rod integrality change that these several kinds of reasons cause all has very strong disguise, and the conventional sense method is powerless, therefore is necessary very much to inquire into simple and practical anchoring rod length non-destructive test method.CN101055171A discloses " a kind of detection is embedded in the method for rock-bolt length in the different medium ", and utilizes CN1831470A disclosed " rock-bolt length ultrasound measuring instrument " instrumentation, has described a kind of anchoring rod length detecting method.See that from these open source literatures employed instrument heavy comparatively in the detection must be used external AC power supply, and not be all purpose instrument.Testing process is also comparatively complicated simultaneously, and therefore, this detection method is not suitable for as a kind of on-the-spot conventional detection means.

Summary of the invention

The objective of the invention is to overcome the shortcoming of prior art, a kind of lossless detection method of anchoring rod length is provided, solve the problem that the testing process that has detection method now is comparatively complicated, be not suitable for on-the-spot detection.

Another object of the present invention provides a kind of employed pick-up unit of lossless detection method of anchoring rod length, and the detecting instrument that solves prior art is comparatively heavy, be not suitable for the on-the-spot problem that detects.

The present invention solves the technical scheme that its technical matters takes:

A kind of lossless detection method of anchoring rod length is characterized in that: said method is carried out according to the following steps:

1) get and tested bolt diameter, material, free bolt that shape is identical, writing down its length is L ₀, adopting pick-up unit of the present invention, the frequency of strobe pulse emission is the centre frequency 2.25Mhz of sensor, analyzes first end face echo of free bolt;

2) each the separation ripple bag to first end face echo of selected free bolt adopts fft analysis, and each separates the crest frequency of ripple bag to obtain the end face echo, and on time-domain diagram, confirms the due ins of the different separation of free bolt ripple bag waveform, data list 1;

3) utilize pick-up unit of the present invention; Set by step 1) the transponder pulse frequency detecting anchoring rod that is provided with; Choose first end face echo of anchoring rod then; According to step 2) described in method handle, each that obtains anchoring rod end face echo separated ripple bag crest frequency and due in thereof, data list 2;

4) from table 1 and table 2, select a minimum data f of frequency value difference respectively ₁With f ₂, i.e. f ₁-f ₂Differ two minimum frequency values, from table, obtain the corresponding due in T of they difference ₁With T ₂

5) according to the length L of computes anchoring rod:

$L={\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="H2010100333389E00013.png,H2010100333389E00022.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\&times;\frac{L_0}{{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="H2010100333389E00012.png,H2010100333389E00013.png"\; state="\{\{state\}\}">T</figure-callout>}}_1}.$

The employed pick-up unit of a kind of lossless detection method of anchoring rod length is characterized in that: described pick-up unit is made up of ultrasonic card, ultrasonic probe and notebook computer, notebook computer and ultrasonic card connection, and ultrasonic card is connected with ultrasonic probe.

Said ultrasonic card is the ultrasonic card of USB-UT350 that U.S. Ultratek company produces.

Said ultrasonic probe is the sonac of 2.25MHz for the centre frequency that Pan American company produces.

Establish check and analysis progress software program in the said notebook computer.

The present invention compared with prior art has the following advantages:

Need carry out frequency sweeping earlier when (1) detecting among the CN101055171A; Employed incoming frequency when confirming test anchoring rod length then; And the present invention is because the ripple that sonac produces is a multifrequency ripple; In the test frequency that uses anchor pole in the engineering can being included in, therefore, need not to carry out frequency sweeping.The present invention compared with prior art test process is simple, and test error is little;

(2) whole check and analysis process can be accomplished by computing machine through programming automatically, so detection speed is fast;

(3) pick-up unit has only 2 kilograms, and does not need external power supply, and therefore, pick-up unit is simple, light, practical;

(4) parts of equipment therefor of the present invention all are commercial all purpose instrument, element, and therefore, promote the use of at the scene of being more suitable for.

Description of drawings:

Fig. 1 is the structural representation of detection device thereof of the present invention;

Fig. 2 is a free bolt end face reflectogram;

The FFT figure of a certain separation ripple of Fig. 3 free bolt end face echo bag;

Fig. 4 anchoring rod end face reflectogram;

Table 1 free bolt end face echo data;

Table 2 anchoring rod end face echo data.

Embodiment

The present invention is further described through embodiment below in conjunction with this accompanying drawing.

As shown in Figure 1, the employed device of a kind of lossless detection method of anchoring rod length is made up of ultrasonic card, ultrasonic probe and notebook computer, notebook computer and ultrasonic card connection, and ultrasonic card is connected with ultrasonic probe.

Said ultrasonic card is the ultrasonic card of USB-UT350 that U.S. Ultratek company produces.The main effect of this ultrasonic card is the square-wave signal of emission setpoint frequency and periodicity, can receive echoed signal at same passage simultaneously.The voltage that transmits is up to 300 volts.These parameters can be through the programmed control in the coupled notebook computer.The visible following network address of the concrete parameter of other of this equipment:

http://www.usultratek.com/products/usb-ut350t.htm

Said ultrasonic probe is the sonac of 2.25MHz for the centre frequency that Pan American company produces.

Establish check and analysis progress software program in the said notebook computer.

Free bolt length is the smooth round steel of 1.8m, diameter 20mm in this instance; Anchoring rod length to be measured is 2m, and anchoring medium is a sand-cement slurry.

A kind of lossless detection method of anchoring rod length, carry out according to the following steps:

1) adopt pick-up unit of the present invention, the frequency of strobe pulse emission is the centre frequency 2.25Mhz of sensor, and the free bolt that 1.8m is long is tested, and analyzes first end face echo of free bolt, and first test echo of this free bolt is as shown in Figure 2;

2) each of resultant echo being separated ripple bag carries out fft analysis (FFT is FFT; It is a prevailing algorithm in the signal Processing; Be simple technique well known in the art); It is as shown in Figure 3 to obtain frequency component, on the time-history curves of echo, obtains each simultaneously and separates the pairing due in of ripple bag and tabulate 1;

3) utilize pick-up unit of the present invention; Set by step 1) the transponder pulse frequency detecting anchoring rod that is provided with; Choose first end face echo of anchoring rod then, according to step 2) described in method handle, obtain that anchoring rod is different to be separated ripple bag crest frequency and due in and tabulate 2;

4) data of contrast table 1 and table 2; Select two minimum data of difference on the frequency (because reading error and anchor structure are different to the influence of the guided wave mode influence when the different frequency; Therefore the frequency data in two tables are not necessarily identical; Choose two table medium frequency values during selection as far as possible and differ minimal data), i.e. f ₁=2.29MHz and f ₂=2.30MHz obtains corresponding echo due in, i.e. T ₁=644.6 and T ₂=722.Can obtain anchoring rod length according to computing formula.

$L={\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="H2010100333389E00013.png,H2010100333389E00022.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\&times;\frac{L_0}{{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="H2010100333389E00012.png,H2010100333389E00013.png"\; state="\{\{state\}\}">T</figure-callout>}}_1}=722\&times;\frac{1.8}{644.6}=2.01m$

Test error is merely 0.5%.

Claims (1)

1. the lossless detection method of an anchoring rod length, it is characterized in that: said method is carried out according to the following steps:

1) get and tested bolt diameter, material, free bolt that shape is identical, writing down its length is L ₀, adopting the cannot-harm-detection device of the anchoring rod length of forming by ultrasonic card, ultrasonic probe and notebook computer, the frequency of strobe pulse emission is the centre frequency 2.25Mhz of sensor, first end face echo of analysis free bolt;

2) each the separation ripple bag to first end face echo of selected free bolt adopts fft analysis, and each separates the crest frequency of ripple bag to obtain the end face echo, and on time-domain diagram, confirms the due ins of the different separation of free bolt ripple bag waveform, data list 1;

3) utilize the cannot-harm-detection device of the anchoring rod length of forming by ultrasonic card, ultrasonic probe and notebook computer; Set by step 1) the transponder pulse frequency detecting anchoring rod that is provided with; Choose first end face echo of anchoring rod then; According to step 2) described in method handle, each that obtains anchoring rod end face echo separates ripple bag crest frequency and due in thereof, data list 2;

4) from table 1 and table 2, select a minimum data f of frequency value difference respectively ₁With f ₂, i.e. f ₁-f ₂Differ two minimum frequency values, from table, obtain the corresponding due in T of they difference ₁With T ₂

5) according to the length L of computes anchoring rod:

$L=T_2\&times;\frac{L_0}{T_1}.$

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