CN112179298A - Method for detecting length of anchor rod through natural frequency - Google Patents
Method for detecting length of anchor rod through natural frequency Download PDFInfo
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- CN112179298A CN112179298A CN202010849898.5A CN202010849898A CN112179298A CN 112179298 A CN112179298 A CN 112179298A CN 202010849898 A CN202010849898 A CN 202010849898A CN 112179298 A CN112179298 A CN 112179298A
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- anchor rod
- natural frequency
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- frequency
- detecting
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- 238000000034 method Methods 0.000 title claims abstract description 47
- 238000012360 testing method Methods 0.000 claims description 28
- 239000000523 sample Substances 0.000 claims description 27
- 239000011435 rock Substances 0.000 claims description 17
- 239000000463 material Substances 0.000 claims description 11
- 238000004873 anchoring Methods 0.000 claims description 10
- 238000005259 measurement Methods 0.000 claims description 8
- 238000009434 installation Methods 0.000 abstract description 17
- 238000001514 detection method Methods 0.000 abstract description 7
- 238000013461 design Methods 0.000 description 3
- 229910000759 E-Material Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000011440 grout Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Classifications
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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
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
The invention discloses a method for detecting the length of an anchor rod through natural frequency and a method for detecting the length of the anchor rod relative to the natural frequency. The method for detecting the length of the anchor rod through the natural frequency is not influenced by the installation environment and the installation depth of the installation method, and the detection is quick and accurate; the method for detecting the length of the anchor rod through the relative natural frequency has the advantages of quick detection, simplified calculation and accurate result.
Description
Technical Field
The invention relates to the technical field of engineering detection, in particular to a method for detecting the length of an anchor rod through natural frequency.
Background
The anchor rod is used as one of main support forms of underground engineering and rock slopes, plays an important role in maintaining the stability of civil engineering, and particularly has an obvious reinforcing effect on rock bodies in joint fissure rock bodies. The anchor rod always is the serious disaster area of material stealing in construction, carries out the stock length to the anchor rod that has inserted the ground layer and detects, can effectively avoid in the work process to the material subtracting of stealing of stock length.
The anchor rod quality detector commonly used in the market consists of a transmitting seismic source, a detector, a host and analysis processing software. And (3) emitting elastic waves generated by the seismic source, transmitting along the anchor rod and radiating energy to the periphery of the anchor rod, detecting a reflected echo by the detector, and analyzing and storing the signal by the detector. The energy intensity and arrival time of the reflected signal depends on the grouting conditions around or at the end of the bolt. By processing and analyzing the signals, the bolt length and overall quality of the grout can be determined. However, the length of the anchor rod is limited, and the propagation speed of the elastic wave is high, so that the time difference between the occurrence and the reflection of the elastic wave is very short, the signal capturing difficulty is high, errors are easy to occur, and the result of detecting the length of the anchor rod is inaccurate. In addition, it is very difficult to detect the length of the anchor rod using the geological radar in the tunnel, and the anchor rod length cannot be accurately detected in consideration of the installation manner of the tunnel anchor rod and the electromagnetic wave propagation characteristics of the geological radar.
Disclosure of Invention
In view of the above, the present invention provides a method for detecting a length of an anchor rod by using a natural frequency and a method for detecting a length of an anchor rod by using a relative natural frequency, which are not affected by an installation environment and an installation depth of an installation method, and are fast and accurate.
In order to achieve the purpose, the invention adopts the following technical scheme: a method of detecting bolt length through natural frequency, comprising the steps of:
s1, fixing a frequency probe of a natural frequency measurement system at the rear end of an anchor rod;
s2, testing the natural frequency of the anchor rod 1 by adopting a knocking method;
and S3, calculating the length of the anchor rod according to the measured natural frequency.
Furthermore, the front end of the anchor rod is inserted into the rock wall, the rear end of the anchor rod is exposed, and the frequency probe is fixed at the rear end of the anchor rod.
Furthermore, the rear end of the anchor rod close to the rock wall is fixed through a backing plate and a nut, and the front end of the anchor rod is provided with an anchor head or a drill bit.
Further, the natural frequency measuring system comprises a frequency probe, a control box and a test host.
Furthermore, in the step 2, the frequency probe collects resonance signals and transmits the resonance signals back to the control box, and then the test host calculates the natural frequency.
A method of detecting bolt length through relative natural frequencies, comprising the steps of:
s1, measuring the fixed frequency of the anchor rod which is made of the same material and has the same diameter and the known length by adopting a radial knocking method, and taking the fixed frequency as a standard value of the inherent frequency;
s2, fixing a frequency probe of the natural frequency measurement system at the rear end of the anchoring state anchor rod to be measured;
s3, testing the natural frequency of the anchor rod in the anchoring state by adopting a radial knocking method, and taking the natural frequency as a relative value of the natural frequency;
and S4, calculating the actual length of the anchor rod in the anchoring state by combining the length value of the anchor rod with the known length according to the inverse relation between the length of the anchor rod with the same material and the same diameter and the natural frequency and the ratio of the relative value of the natural frequency to the standard value of the natural frequency obtained by testing.
Furthermore, the front end of the anchor rod is inserted into the rock wall, the rear end of the anchor rod is exposed, and the frequency probe is fixed at the rear end of the anchor rod.
Furthermore, the rear end of the anchor rod close to the rock wall is fixed through a backing plate and a nut, and the front end of the anchor rod is provided with an anchor head or a drill bit.
Further, the natural frequency measuring system comprises a frequency probe, a control box and a test host.
Furthermore, in the step 3, the frequency probe collects resonance signals and transmits the resonance signals back to the control box, and then the test host calculates the natural frequency.
The invention has the beneficial effects that:
the method for detecting the length of the anchor rod through the natural frequency is characterized in that the natural frequency of the anchor rod is tested by adopting a tapping method, the length of the anchor rod is calculated according to a formula, the method is not influenced by the installation environment and the installation depth of the installation method, and the detection is rapid and accurate. The method for detecting the length of the anchor rod through the relative natural frequency and the method for calculating the length of the anchor rod according to the relative natural frequency proportion are not influenced by the installation environment and the installation depth of the installation method, are quick in detection and accurate in result, and simplify calculation. The front end of the anchor rod is inserted into the rock wall, the rear end of the anchor rod is exposed, the frequency probe is fixed at the rear end of the anchor rod, resonance signals can be accurately acquired, and the frequency probe is convenient to install and detach. The control box and the test host adopt an integrated design, and the test speed is high, accurate and reliable, the operation is simple and convenient, the volume is small, the weight is light, and the carrying is convenient.
Drawings
Figure 1 is a block diagram of the anchor and natural frequency measurement system of the present invention.
Reference numerals: 1-anchor rod; 2-rock wall; 3-backing plate; 4-a nut; 5-a drill bit; 6-frequency probe; 7-a control box; 8-test the host computer.
Detailed Description
The following are specific examples of the present invention and further describe the technical solutions of the present invention, but the present invention is not limited to these examples.
Example 1
A method of detecting bolt length through natural frequency, comprising the steps of:
s1, fixing a frequency probe 6 of a natural frequency measurement system at the rear end of an anchor rod 1;
s2, testing the natural frequency of the anchor rod 1 by adopting a knocking method;
s3, according to a formula
The length of the anchor 1 is calculated, wherein i-ith order natural frequency, omegaiThe natural frequency of the ith order, the L-bolt length, the modulus of elasticity of the E-material, and the ρ -material density.
Example 2
The present embodiment is different from embodiment 1 in that: in 1 front end of stock inserted rock wall 2, 1 rear ends of stock expose, and 6 heads of frequency probe are fixed in 1 rear end of stock, can accurate acquisition resonance signal, and the installation is dismantled conveniently moreover.
Example 3
The present embodiment is different from embodiment 1 in that: the rear end of the anchor rod 1 close to the rock wall 2 is fixed through a backing plate 3 and a nut 4, and the front end of the anchor rod 1 is provided with an anchor head or a drill bit 5.
Example 4
The present embodiment is different from embodiment 1 in that: the natural frequency measuring system comprises a frequency probe 6, a control box 7 and a test host 8. The control box 7 and the test host 8 adopt an integrated design, and the test speed is high, accurate and reliable, the operation is simple and convenient, the volume is small, the weight is light, and the carrying is convenient. The natural frequency measuring system can also be purchased directly from the market, and the anchor rod length detection can be carried out only by simple installation.
Example 5
This embodiment is different from embodiment 4 in that: in the step 2, the frequency probe acquires resonance signals and transmits the resonance signals back to the control box 7, and then the test host 8 calculates the natural frequency.
Example 6
A method of detecting bolt length through relative natural frequencies, comprising the steps of:
s1, measuring the fixed frequency of the anchor rod which is made of the same material and has the same diameter and the known length by adopting a radial knocking method, and taking the fixed frequency as a standard value of the inherent frequency;
s2, fixing a frequency probe 6 of the natural frequency measurement system at the rear end of the anchoring state anchor rod 1 to be tested;
s3, testing the natural frequency of the anchor rod 1 in the anchoring state by adopting a radial knocking method, and taking the natural frequency as a relative value of the natural frequency;
and S4, calculating the actual length of the anchor rod 1 in the anchoring state according to the inverse relation between the length of the anchor rod made of the same material and the same diameter and the natural frequency, and the ratio of the relative value of the natural frequency to the standard value of the natural frequency obtained by testing, and the length value of the anchor rod with the known length.
The elastic modulus and the density of the anchor rods made of the same material and the same diameter are the same, so that the length of the anchor rods made of the same material and the same diameter is in inverse proportion to the natural frequency. The method for calculating the length of the anchor rod according to the relative natural frequency proportion can calculate the actual length of the anchor rod to be measured according to the actual measurement natural frequency value of the anchor rod to be measured in the anchoring state and the inverse proportion by only calibrating the natural frequency of the anchor rod with the known length in advance.
Example 7
This embodiment is different from embodiment 6 in that: in 1 front end of stock inserted rock wall 2, 1 rear ends of stock expose, and 6 heads of frequency probe are fixed in 1 rear end of stock, can accurate acquisition resonance signal, and the installation is dismantled conveniently moreover.
Example 8
This embodiment is different from embodiment 6 in that: the rear end of the anchor rod 1 close to the rock wall 2 is fixed through a backing plate 3 and a nut 4, and the front end of the anchor rod 1 is provided with an anchor head or a drill bit 5.
Example 9
This embodiment is different from embodiment 6 in that: the natural frequency measuring system comprises a frequency probe 6, a control box 7 and a test host 8. The control box 7 and the test host 8 adopt an integrated design, and the test speed is high, accurate and reliable, the operation is simple and convenient, the volume is small, the weight is light, and the carrying is convenient. The natural frequency measuring system can also be purchased directly from the market, and the anchor rod length detection can be carried out only by simple installation.
Example 10
The present embodiment is different from embodiment 9 in that: in the step 3, the frequency probe acquires resonance signals and transmits the resonance signals back to the control box 7, and then the test host 8 calculates the natural frequency.
Finally, the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solutions of the present invention by those of ordinary skill in the art should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.
Claims (10)
1. A method of detecting the length of a bolt through natural frequencies, the method comprising: the method comprises the following steps:
s1, fixing a frequency probe of a natural frequency measurement system at the rear end of an anchor rod;
s2, testing the natural frequency of the anchor rod 1 by adopting a knocking method;
and S3, calculating the length of the anchor rod according to the measured natural frequency.
2. A method of detecting the length of a bolt through natural frequencies as claimed in claim 1, wherein: the front end of the anchor rod is inserted into the rock wall, the rear end of the anchor rod is exposed, and the frequency probe is fixed at the rear end of the anchor rod.
3. A method of detecting the length of a bolt through natural frequencies according to claim 1 or 2, wherein: the rear end of the anchor rod is fixed close to the rock wall through a backing plate and a nut, and the front end of the anchor rod is provided with an anchor head or a drill bit.
4. A method of detecting the length of a bolt through natural frequencies according to claim 1 or 2, wherein: the natural frequency measuring system comprises a frequency probe, a control box and a test host.
5. A method of detecting bolt length through natural frequency according to claim 4 wherein: in step 2, the frequency probe collects resonance signals and transmits the resonance signals back to the control box, and then the test host calculates the natural frequency.
6. A method of detecting the length of a bolt through relative natural frequencies, the method comprising: the method comprises the following steps:
s1, measuring the fixed frequency of the anchor rod which is made of the same material and has the same diameter and the known length by adopting a radial knocking method, and taking the fixed frequency as a standard value of the inherent frequency;
s2, fixing a frequency probe of the natural frequency measurement system at the rear end of the anchoring state anchor rod to be measured;
s3, testing the natural frequency of the anchor rod in the anchoring state by adopting a radial knocking method, and taking the natural frequency as a relative value of the natural frequency;
and S4, calculating the actual length of the anchor rod in the anchoring state by combining the length value of the anchor rod with the known length according to the inverse relation between the length of the anchor rod with the same material and the same diameter and the natural frequency and the ratio of the relative value of the natural frequency to the standard value of the natural frequency obtained by testing.
7. A method of detecting bolt length by relative natural frequency according to claim 6 wherein: the front end of the anchor rod is inserted into the rock wall, the rear end of the anchor rod is exposed, and the frequency probe is fixed at the rear end of the anchor rod.
8. A method of detecting bolt length by relative natural frequency according to claim 6 or 7 wherein: the rear end of the anchor rod is fixed by a backing plate and a nut close to the rock wall, and the front end of the anchor rod is provided with an anchor head or a drill bit.
9. A method of detecting bolt length by relative natural frequency according to claim 6 or 7 wherein: the natural frequency measuring system comprises a frequency probe, a control box and a test host.
10. A method of detecting bolt length by relative natural frequency according to claim 9 wherein: and 3, collecting resonance signals by the frequency probe and transmitting the resonance signals back to the control box, and calculating the natural frequency by the test host.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010849898.5A CN112179298B (en) | 2020-08-21 | 2020-08-21 | Method for detecting length of anchor rod through natural frequency |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010849898.5A CN112179298B (en) | 2020-08-21 | 2020-08-21 | Method for detecting length of anchor rod through natural frequency |
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| CN112179298A true CN112179298A (en) | 2021-01-05 |
| CN112179298B CN112179298B (en) | 2021-11-26 |
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2344092A1 (en) * | 2001-04-12 | 2002-10-12 | Dalhousie University | A method and apparatus for the measurement of corrosion and damage in installed bolts, rods and bars |
| CN101131319A (en) * | 2007-10-19 | 2008-02-27 | 北京工业大学 | Method for nondestructive detecting length of high speed highway guardrail upright post by ultrasonic guided wave |
| CN101438130A (en) * | 2006-05-08 | 2009-05-20 | 瑞尼斯豪公司 | Surface measurement probe |
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| CN102207404A (en) * | 2011-03-16 | 2011-10-05 | 江苏中矿立兴能源科技有限公司 | Non-destructive testing method for natural frequency of transverse vibration of non-fully grouted anchoring bolt in coal mine |
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-
2020
- 2020-08-21 CN CN202010849898.5A patent/CN112179298B/en not_active Expired - Fee Related
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| CA2344092A1 (en) * | 2001-04-12 | 2002-10-12 | Dalhousie University | A method and apparatus for the measurement of corrosion and damage in installed bolts, rods and bars |
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| CN112179298B (en) | 2021-11-26 |
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