Nondestructive testing methods for anchor bolts

Abstract

The present invention relates to the field of anchor rod detection technology, and provides a method for non-destructive detection of anchor rods, wherein the anchor rod comprises an insertion section inserted into an anchor hole and an exposed section exposed outside the anchor hole, and comprises: determining the position of the exposed section at a preset distance from the anchor hole as a detection point; exciting and generating sound waves at the detection point, and receiving a first reflected wave caused by the sound waves at the detection point; drawing a waveform diagram based on the first reflected wave, and determining the grouting density of the anchor rod and the position of the grouting defect based on the waveform diagram. The non-destructive detection method for anchor rods of the present invention, by reasonably setting a preset distance between the detection point and the anchor hole, enables the detection point to be as close to the anchor hole as possible, reduces the energy loss of the sound wave and the first reflected wave during the transmission process, and is conducive to improving the accuracy of the detection result. There is no need to cut off the exposed section, and there is no need to set auxiliary ribs, which effectively solves the defect of difficulty in detecting special-shaped anchor rods such as long exposed anchor rods with elbows in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of anchor rod detection, and in particular to a non-destructive detection method for anchor rods. Background Art

[0002] Nondestructive testing of long, exposed anchor rods with elbows and other special shapes is a major challenge in the industry. To obtain accurate test results, the exposed portion of the anchor rod usually needs to be cut off. However, in some testing scenarios, such as when testing long, exposed anchor rods in key areas such as rock anchor beams, nondestructive testing is usually required, and cutting the anchor rod is not allowed. To address this problem, some hydropower projects have adopted the method of pre-placed auxiliary reinforcement. Although this method can evaluate the anchoring quality of long exposed anchor rods, it results in increased investment and makes the control of the anchor rod construction process more difficult. Moreover, if the pre-placed auxiliary reinforcement construction effect is not good, not only will it not achieve the testing effect, but it will also have a certain impact on the grouting fullness in the hole. Summary of the Invention

[0003] The present invention provides a non-destructive testing method for anchor rods, which is used to solve the defect in the prior art that it is difficult to detect special-shaped anchor rods such as long exposed anchor rods with elbows.

[0004] The present invention provides a method for nondestructive testing of an anchor rod, wherein the anchor rod comprises an insertion section inserted into an anchor hole and an exposed section exposed outside the anchor hole, comprising:

[0005] Determine the position of the exposed section at a preset distance from the anchor hole as a detection point;

[0006] Exciting and generating an acoustic wave at the detection point, and receiving a first reflected wave caused by the acoustic wave at the detection point;

[0007] A waveform diagram is drawn according to the first reflected wave, and the grouting density of the anchor rod and the location of the grouting defect are determined according to the waveform diagram.

[0008] According to the anchor bolt nondestructive testing method of the present invention, before the step of determining the position of the exposed section at a preset distance from the anchor hole as the testing point, the method further includes:

[0009] Making an anchor rod model, and when the anchor rod model has exposed sections of different lengths, exciting and generating acoustic waves at the detection point, and obtaining free end reflected waves formed by reflection of the exposed section at the detection point;

[0010] Extracting waveform characteristics of the free end reflected wave and constructing a filtering model;

[0011] Accordingly, the step of drawing a waveform diagram according to the first reflected wave includes:

[0012] Filtering the first reflected wave based on the filtering model to remove interference waves and obtain filtered data;

[0013] The waveform graph is drawn according to the filtered data.

[0014] According to the anchor rod nondestructive testing method of the present invention, the preset distance is not greater than 12 cm and not less than 8 cm.

[0015] According to the anchor bolt nondestructive testing method of the present invention, before the step of exciting and generating sound waves at the testing point, the method further comprises:

[0016] Installing an excitation device and a receiving device at the detection point;

[0017] The exciting device is used to excite and generate the sound wave; and the receiving device is used to receive the first reflected wave.

[0018] According to the anchor rod nondestructive testing method of the present invention, the excitation end face of the excitation device and the receiving end face of the receiving device are both perpendicular to the length direction of the insertion section.

[0019] According to the anchor bolt nondestructive testing method of the present invention, the step of installing the excitation device and the receiving device at the testing point includes:

[0020] Install a fixture at the detection point, and install the excitation device and the receiving device on the fixture;

[0021] The clamp is provided with a mounting hole, the exposed section is passed through the mounting hole, and the hole wall of the mounting hole is in contact with the exposed section.

[0022] According to the anchor rod non-destructive testing method of the present invention, a mounting plane is provided on the outer wall of the clamp, and the excitation device and the receiving device are mounted on the mounting plane.

[0023] According to the anchor rod nondestructive testing method of the present invention, the clamp includes a first part and a second part, the first part and the second part are detachably connected, and the first part and the second part are aligned to form the mounting hole.

[0024] The present invention provides a nondestructive testing method for anchor rods. By determining the location of an exposed section at a preset distance from the anchor hole as a testing point, sound waves are generated at the testing point, and the waveform signal of the first reflected wave generated by the sound wave within the anchor rod is collected. A waveform diagram drawn based on the waveform signal can be used to analyze the grouting density and the location of grouting defects at various locations on the anchor rod. Furthermore, by reasonably setting a preset distance between the testing point and the anchor hole, the testing point can be positioned as close to the anchor hole as possible, reducing energy loss during transmission of the sound wave and the first reflected wave, thereby improving the accuracy of the test results. The method eliminates the need to truncate the exposed section or install auxiliary reinforcement, effectively resolving the existing technical issues of difficulty in testing special-shaped anchor rods, such as long exposed sections with elbows. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is one of the flow charts of the anchor rod nondestructive testing method provided by the embodiment of the present invention.

[0027] Figure 2 This is the second flow chart of the anchor rod nondestructive testing method provided by the embodiment of the present invention.

[0028] Figure 3 It is a schematic diagram of the anchor rod, anchor hole, excitation device, receiving device and clamp provided in an embodiment of the present invention.

[0029] Figure 4 Schematic diagram of a clamp provided in an embodiment of the present invention.

[0030] Figure 5 This is one of the test result diagrams of the first test of the embodiment of the present invention.

[0031] Figure 6 This is the second test result diagram of the first test of the embodiment of the present invention.

[0032] Figure 7 This is one of the test result diagrams of the second test of the embodiment of the present invention.

[0033] Figure 8 This is the second test result diagram of the second test of the embodiment of the present invention.

[0034] Figure 9 This is one of the test result diagrams of the third test of the embodiment of the present invention.

[0035] Figure 10 This is the second test result diagram of the third test of the embodiment of the present invention.

[0036] Figure 11 This is the third test result diagram of the third test of the embodiment of the present invention.

[0037] Figure 12 FIG4 is the test result diagram of the third test of the embodiment of the present invention.

[0038] Figure 13 This is the fifth test result diagram of the third test of the embodiment of the present invention.

[0039] Figure 14 This is one of the test result diagrams of the fourth test of the embodiment of the present invention.

[0040] Figure 15 This is the second test result diagram of the fourth test of the embodiment of the present invention.

[0041] Figure 16 This is the third test result diagram of the fourth test of the embodiment of the present invention.

[0042] Figure 17 FIG4 is the test result diagram of the fourth test of the embodiment of the present invention.

[0043] Figure 18 This is the fifth test result diagram of the fourth test of the embodiment of the present invention.

[0044] Figure 19 This is the sixth test result diagram of the fourth test of the embodiment of the present invention.

[0045] Reference numerals:

[0046] 1. Anchor rod; 11. Insertion section; 12. Exposed section;

[0047] 2. Anchor hole; 3. Excitation device; 4. Receiving device;

[0048] 5. Clamp; 51. Mounting hole; 52. First part; 53. Second part. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0050] The following combination Figures 1-19The present invention describes the anchor bolt nondestructive testing method.

[0051] In some embodiments, as Figure 1 and Figure 3 As shown, the present invention provides a method for nondestructive testing of an anchor rod, wherein the anchor rod 1 includes an insertion section 11 inserted into the anchor hole 2 and an exposed section 12 exposed outside the anchor hole 2. The method for nondestructive testing of the anchor rod includes the following steps:

[0052] Step S101: determining a position of the exposed section at a preset distance from the anchor hole as a detection point.

[0053] Step S102: Excite and generate an acoustic wave at the detection point, and receive a first reflected wave caused by the acoustic wave at the detection point.

[0054] Step S103: drawing a waveform diagram according to the first reflected wave, and determining the grouting density of the anchor rod and the location of the grouting defect according to the waveform diagram.

[0055] First, before testing, it is necessary to determine the testing point on the exposed section 12 of the anchor rod 1. The distance between the testing point and the anchor hole 2 is a preset distance. It is understood that the preset distance can be determined based on factors such as the overall length of the anchor rod 1, the length of the exposed section 12, the structural shape of the exposed section 12, or can also be an empirical value obtained after multiple tests.

[0056] It can be understood that the detection point needs to be as close to the anchor hole 2 as possible so that sound waves can be excited at the detection point later. When the sound waves are transmitted to the insertion section 11 of the anchor rod 1, the length of the exposed section 12 through which the sound waves pass can be reduced, thereby reducing the energy loss of the sound waves when they are transmitted to the insertion section 11, and thus making the intensity of the sound waves and the corresponding reflected waves higher.

[0057] After determining the test point, equipment for stimulating sound waves and receiving reflected waves can be set up at the test point. Sound waves are generated at the test point, propagating along anchor rod 1 and forming a first reflected wave within anchor rod 1. The waveform, period, wave number, and other characteristics of the first reflected wave are affected by the grouting density around anchor rod 1. By collecting the waveform signal of the first reflected wave and drawing the corresponding waveform graph, the grouting density at various locations on anchor rod 1 can be determined by analyzing the waveform, period, wave number, and other characteristics of the first reflected wave, as well as the locations of grouting defects, thereby achieving non-destructive testing of the anchoring quality of the anchor rod.

[0058] The anchor rod nondestructive testing method of the present invention determines the position of the exposed section 12 at a preset distance from the anchor hole 2 as the testing point, excites and generates sound waves at the testing point, and collects the waveform signal of the first reflected wave generated by the sound wave in the anchor rod 1. The waveform diagram drawn based on the waveform signal can be used to analyze the grouting density and the location of grouting defects at various positions of the anchor rod 1. At the same time, by reasonably setting the preset distance between the testing point and the anchor hole 2, the testing point can be as close to the anchor hole 2 as possible, reducing the energy loss of the sound wave and the first reflected wave during the transmission process, which is conducive to improving the accuracy of the test results. There is no need to cut off the exposed section 12 or set auxiliary reinforcement, which effectively solves the defect of the existing technology that is difficult to detect special-shaped anchor rods such as long exposed anchor rods with elbows.

[0059] It is understandable that when the exposed section 12 of the anchor rod 1 has a special-shaped structure such as a curved section, the detection point is set on the portion of the exposed section 12 that is directly connected to the inserted section 11 and coaxial with the inserted section 11.

[0060] In some embodiments, as Figure 2 and Figure 3 As shown, before step S101: determining the position of the exposed section at a preset distance from the anchor hole as the detection point, the method further includes:

[0061] Step S080: making an anchor model, and in the case where the anchor model has exposed sections of different lengths, exciting and generating acoustic waves at a detection point, and obtaining a free end reflected wave formed by reflection of the exposed section at the detection point.

[0062] Step S090: extracting the waveform characteristics of the free end reflected wave and constructing a filtering model.

[0063] Before testing the anchor rod 1 in the actual application scenario, multiple anchor rod models with the same specifications as the anchor rod 1 can be made first, and the anchor rod model can be cut into exposed section models of different lengths. The corresponding detection points are determined on each exposed section model according to the preset distance in the aforementioned embodiment, and excitation is set at the detection points to generate sound waves. The sound waves will form free end reflection waves in the exposed section model. By collecting the free end reflection wave signals generated by the exposed section models of different lengths, the waveform characteristics of the free end reflection wave signals generated by the exposed section models at each length can be extracted, and a filtering model is established based on the length of the exposed section 12 and the corresponding waveform characteristics.

[0064] Accordingly, in this embodiment, the step of drawing a waveform diagram according to the first reflected wave includes:

[0065] The first reflected wave is filtered based on the filtering model to remove the interference wave and obtain filtered data.

[0066] Draw a waveform graph based on the filtered data.

[0067] During actual detection, the first reflected wave collected at the detection point is actually a synthetic wave formed at the detection point by the reflected wave generated by the exposed section 12 and the reflected wave generated by the inserted section 11. By performing direction filtering on the first reflected wave based on the filtering model, the interference caused by the reflected wave generated by the exposed section 12 in the first reflected wave can be filtered out, thereby obtaining the corresponding filtered data. According to the waveform diagram of the filtered data return, the waveform signal-to-noise ratio is higher, which can better reflect the grouting density of each position of the inserted section 11, thereby making the detection result more accurate and reliable.

[0068] Specifically, in some embodiments, the preset distance is no greater than 12 cm and no less than 8 cm. In this embodiment, by limiting the preset distance to between 8 cm and 12 cm, the detection point can be placed as close to the anchor hole 2 as possible, reducing energy loss of the sound waves and reflected waves during passage through the exposed section 12, thereby improving detection accuracy. Furthermore, a certain distance is maintained between the detection point and the anchor hole 2 to facilitate installation of appropriate instruments and equipment.

[0069] For example, the preset distance is 12 cm or 8 cm. Preferably, the preset distance can be 10 cm, and the detected waveform effect is the best.

[0070] In some embodiments, as Figure 3 and Figure 4 As shown, before the step of exciting the detection point to generate the sound wave, the following steps are also included:

[0071] Install the excitation device and the receiving device at the detection point.

[0072] The exciting device 3 is used to generate sound waves; the receiving device 4 is used to receive the first reflected wave.

[0073] In this embodiment, by installing an excitation device 3 and a receiving device 4 at the detection point, the excitation device 3 can generate sound waves at the detection point, and the receiving device 4 is used to receive the first reflected wave induced by the sound wave in the anchor rod 1.

[0074] Furthermore, in some embodiments, Figure 3 As shown, the excitation end face of the excitation device 3 and the receiving end face of the receiving device 4 are both perpendicular to the length direction of the insertion section 11. In this embodiment, by aligning the excitation end face of the excitation device 3 with the length direction of the insertion section 11, the excitation direction of the excitation device 3 is set along the length direction of the insertion section 11. Similarly, the receiving direction of the receiving device 4 is also set along the length direction of the insertion section 11. This is beneficial for improving the waveform signal quality of the first reflected wave received by the receiving device 4, thereby improving the quality of the waveform diagram drawn based on the waveform signal, so as to better analyze the grouting density at various positions of the insertion section 11.

[0075] In some embodiments, as Figure 3 and Figure 4 As shown, the steps of installing the excitation device and the receiving device at the detection point include the following steps:

[0076] Install a fixture at the detection point, and install the excitation device and the receiving device on the fixture.

[0077] The fixture 5 is provided with a mounting hole 51 , and the exposed section 12 is passed through the mounting hole 51 , and the hole wall of the mounting hole 51 is in contact with the exposed section 12 .

[0078] In this embodiment, before installing the excitation device 3 and the receiving device 4, it is necessary to first set the fixture 5 at the detection point of the exposed section 12, and then install the excitation device 3 and the receiving device 4 on the fixture 5. The wall of the mounting hole 51 of the fixture 5 can fit tightly with the exposed section 12, so that the fixture 5 and the anchor rod 1 have a high degree of coupling and integrity, so that the sound waves are distorted when propagating between the fixture 5 and the anchor rod 1, so that the fixture 5 can transmit the sound waves between the anchor rod 1 and the excitation device 3 and the receiving device 4, and prevent the anchor rod 1 and the excitation device 3 from directly contacting the anchor rod 1. It is understandable that the surface of the anchor rod 1 is usually rough and may have uneven structures or threads. If the excitation device 3 and the receiving device 4 are directly connected to the anchor rod 1, it is difficult to make the excitation device 3 and the receiving device 4 in close contact with the anchor rod 1. At the same time, during the detection process, the anchor rod 1 may also be affected by the sound waves and vibrate slightly, further causing the excitation device 3 and the receiving device 4 to have poor contact with the anchor rod 1, affecting the detection effect. The clamp 5 of this embodiment can ensure the effect of sound wave transmission between the excitation device 3 and the receiving device 4 and the anchor rod 1 during the detection process, so as to improve the accuracy of the detection results.

[0079] Based on the above embodiment, the present application conducted a comparative test on the anchor rod 1 with and without the fixture 5 installed, wherein the first test parameters are as follows:

[0080] The length of the anchor rod 1 is 2.0 m, the length of the inserted section 11 is 2.0 m, and the length of the exposed section 12 is 0.0 m.

[0081] Figure 5 The results of the detection of excitation and reception directly at the end of the anchor rod 1 are shown. The upper figure is the waveform diagram of the received waveform signal, and the lower figure is the phase diagram. The overall density of the inserted section 11 is 50%.

[0082] Figure 6 The figure shows the test results of directly installing a fixture 5 on the end of the anchor rod 1 and performing excitation and reception on the fixture 5. The upper figure is the waveform diagram of the received waveform signal, and the lower figure is the phase diagram. The overall density of the inserted section 11 is 50%.

[0083] The parameters for the second test are as follows:

[0084] The length of the calf anchor rod 1 of the factory building is 5.4m, and the length of the exposed section 12 is 0.1m.

[0085] Figure 7 The results of the detection of excitation and reception directly at the end of the anchor rod 1 are shown. The upper figure is the waveform diagram of the received waveform signal, and the lower figure is the phase diagram. The overall density of the inserted section 11 is 93%.

[0086] Figure 8 The figure shows the test results of adding a fixture 5 directly to the end of the anchor rod 1 and performing excitation and reception on the fixture 5. The upper figure is the waveform diagram of the received waveform signal, and the lower figure is the phase diagram. The overall density of the inserted section 11 is 92%.

[0087] The third test conditions and parameters are as follows:

[0088] The length of the anchor rod 1 is 9.0 m, the length of the inserted section 11 is 7.5 m, and the length of the exposed section 12 is 1.5 m. The inserted section 11 is inserted into a long tube and grouting is performed in the long tube.

[0089] Figure 9 The results of the test are shown for excitation and reception directly at the end of the anchor rod 1. Multiple strong reflections are clearly visible in the exposed section 12. The upper figure is a waveform diagram of the received waveform signal, and the lower figure is a phase diagram. The overall density of the inserted section 11 detected is 91%.

[0090] Figure 10 It shows that auxiliary reinforcement is set on one side of the anchor rod 1. The length of the auxiliary reinforcement is 7.6m, of which the length of the exposed part is 0.1m. The detection results of excitation and reception are performed at the end of the auxiliary reinforcement. The upper figure is the waveform diagram of the received waveform signal, and the lower figure is the phase diagram. The measured overall density of the inserted section 11 is 96%.

[0091] Figure 11 The figure shows the test results of installing a fixture 5 at a distance of 0.1m between the exposed section 12 and the anchor hole 2, and performing excitation and reception on the fixture 5. The upper figure is a waveform diagram of the received waveform signal, and the lower figure is a phase diagram. The measured overall density of the inserted section 11 is 97%.

[0092] Figure 12 The figure shows the test results of cutting open a long pipe and installing a fixture 5 0.1m between the exposed section 12 and the anchor hole 2. The upper figure shows the waveform of the received signal, while the lower figure shows the phase diagram. The overall density of the inserted section 11 was measured to be 96%.

[0093] Figure 13The figure shows the test results of cutting a long tube open and then cutting off the exposed section 12, which is 0.1m long. Excitation and reception are then performed directly at the end of this section. The upper figure shows the waveform of the received signal, and the lower figure shows the phase diagram. The overall density of the inserted section 11 was measured to be 96%.

[0094] It can be seen that when the exposed section 12 is long, the deviation of the detection results of directly exciting and receiving at the end of the anchor rod 1 is large, while the consistency of the truncation detection and the detection method of the present application is better.

[0095] The experimental conditions and parameters of the fourth test are as follows:

[0096] Six long exposed anchor rods 1 were set on the secondary side slope of the ring reservoir road. The design length of the test anchor rods 1 was 9.0 m, the rod diameter was 25 mm, and the length of the exposed section 12 was 2.0 m. A fixture 5 was set on the exposed section 12 at a distance of 0.1 m from the anchor hole 2, and excitation and reception were carried out. The specific parameters of the anchor rod 1 are shown in Table 1.

[0097] Table 1 Supplementary test anchor parameters

[0098]

[0099] Figure 14 The test results for anchor bolt 1 are shown. The upper figure shows the waveform of the received signal, and the lower figure shows the phase diagram. Anchor bolt 1 was designed as a complete anchor bolt without any defects. The test waveform shows a regular pattern, rapid decay, low reflected wave energy, and a grouting density of 92%.

[0100] Figure 15 The test results for anchor bolt 2 (1) are shown. The upper figure shows the waveform of the received signal, and the lower figure shows the phase diagram. The section between anchor bolt 2 and the opening of anchor hole 2, 1.0 to 7.0 m apart, is a grouting defect. The distance between the grouting section and the opening of anchor hole 2 is 0 to 1.0 m, and the designed grouting density is 14.3% (assuming the non-defective section is dense). The waveform diagram shows a strong reflection at a distance of 1.0 m from the opening of anchor hole 2. This point has a distinct abrupt change in the phase spectrum, and the strong reflection energy appears periodically in the phase spectrum. This indicates that the start of the empty grout section at 1.0 m is clearly reflected in the waveform, and the starting position of the waveform reflection matches the actual defect location well.

[0101] Figure 16The test results for anchor bolt 3, number 1, are shown. The 3.5-4.5m distance between anchor bolt 3 and the opening of anchor hole 2 indicates a grouting defect, with a designed grouting density of 85.7% (assuming the non-defective section is dense). The waveform graph shows abrupt phase shifts at 3.55m and 4.58m, with enhanced reflection at 4.58m. This section is designated as an abnormal segment. The actual defect location corresponds well with the waveform response start point, and the tested grouting density is 85.3%.

[0102] Figure 17 The test results for anchor bolt 4, number 1, are shown. The 3.0-5.0m distance between anchor bolt 4 and the opening of anchor hole 2 indicates a grouting defect, with a designed grouting density of 71.4% (assuming the non-defective section is dense). The waveform graph shows abnormal changes at 3.07m and 5.19m, with enhanced reflected waves at 5.19m. This section is designated as an abnormal section. The actual defect location corresponds well with the waveform response start point, and the tested grouting density is 69.7%.

[0103] Figure 18 The test results for anchor bolt 5 (1) are shown. The 6.0-7.0m distance between anchor bolt 5 and the opening of anchor hole 2 indicates a grouting defect, with a designed grouting density of 85.7% (assuming the non-defective section is dense). The waveform graph shows a sudden change at 6.09m, marking this point as the starting point of the abnormal section. The actual defect location agrees well with the waveform response starting point, resulting in a tested grouting density of 85%.

[0104] Figure 19 The test results for anchor bolt 6, number 1, are shown. The grouting defect section is 5.0 to 7.0 meters from the opening of anchor hole 2. The designed grouting density is 71.4% (assuming the non-defective section is dense). The waveform graph shows a sudden change at 5.08 meters, marking 6.08 meters as the starting point of the abnormal section. The actual defect location matches the waveform response starting point well, and the tested grouting density is 73.1%.

[0105] In some embodiments, as Figure 3 and 4 As shown, a mounting plane is provided on the outer wall of the fixture 5, and the exciting device 3 and the receiving device 4 are mounted on the mounting plane.

[0106] In this embodiment, by setting a mounting plane for installing the excitation device 3 and the receiving device 4 on the outer wall of the fixture 5, the mounting plane can ensure close contact with the excitation device 3 and the receiving device 4 during the contact process, thereby ensuring the excitation and reception effects of the sound waves, and further improving the accuracy and reliability of the detection results.

[0107] Optionally, the hole wall of the mounting hole 51 of the clamp 5 may be a smooth hole wall.

[0108] Optionally, in some embodiments, the exposed section 12 of the anchor rod 1 has a first thread, and correspondingly, the wall of the mounting hole 51 of the clamp 5 has a second thread adapted to the first thread, and the clamp 5 and the anchor rod 1 are threadedly connected.

[0109] In this embodiment, a second thread that is compatible with the first thread is provided on the wall of the mounting hole 51 of the clamp 5, so that the clamp 5 and the anchor rod 1 can be tightly connected through threaded matching, while also preventing the clamp 5 from being offset during the detection process. The structure is simple, convenient and practical.

[0110] In some embodiments, as Figure 4 As shown, the clamp 5 includes a first part 52 and a second part 53 , which are detachably connected. The first part 52 and the second part 53 are aligned to form a mounting hole 51 .

[0111] In this embodiment, the clamp 5 is divided into a detachable first part 52 and a second part 53, and the first part 52 and the second part 53 respectively have a partial hole wall structure of the mounting hole 51, so that the first part 52 and the second part 53 can be aligned to form the mounting hole 51, and the operation is more convenient when the clamp 5 is disassembled and assembled on the anchor rod 1.

[0112] Specifically, in some embodiments, the fixture 5 is a carbon steel fixture or an alloy fixture with magnetic attraction properties (such as an iron alloy). Both the carbon steel fixture and the alloy fixture in this embodiment have good structural strength and can be securely fixed to the anchor rod 1. Furthermore, the difference in wave impedance between the carbon steel fixture and the alloy fixture and the anchor rod 1 is small, enabling good transmission of sound waves between the anchor rod 1 and the excitation device 3 and receiving device 4, thereby improving the accuracy and reliability of the detection results.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for nondestructive testing of an anchor rod, wherein the anchor rod comprises an insertion section inserted into an anchor hole and an exposed section exposed outside the anchor hole, characterized in that: include: Determine the position of the exposed section at a preset distance from the anchor hole as a detection point; Exciting and generating an acoustic wave at the detection point, and receiving a first reflected wave caused by the acoustic wave at the detection point; Drawing a waveform diagram according to the first reflected wave, and determining the grouting density of the anchor rod and the location of the grouting defects according to the waveform diagram; Before the step of determining the position of the exposed section at a preset distance from the anchor hole as the detection point, the method further includes: Making a plurality of anchor rod models with the same specifications as the anchor rod, and cutting the anchor rod models into exposed section models of different lengths, determining corresponding detection points on each exposed section model according to the preset distance, exciting and generating sound waves at the detection points, and obtaining free end reflection waves formed by the exposed section reflection at the detection points; Extracting waveform characteristics of the free end reflected wave and constructing a filtering model; Accordingly, the step of drawing a waveform diagram according to the first reflected wave includes: Filtering the first reflected wave based on the filtering model to remove interference waves and obtain filtered data; The waveform graph is drawn according to the filtered data.

2. The anchor bolt nondestructive testing method according to claim 1, characterized in that: The preset distance is no greater than 12 cm and no less than 8 cm.

3. The anchor bolt nondestructive testing method according to claim 1, characterized in that: Before the step of exciting the detection point to generate sound waves, the method further includes: Installing an excitation device and a receiving device at the detection point; The exciting device is used to excite and generate the sound wave; and the receiving device is used to receive the first reflected wave.

4. The anchor bolt nondestructive testing method according to claim 3, characterized in that: The excitation end face of the excitation device and the receiving end face of the receiving device are both perpendicular to the length direction of the insertion section.

5. The anchor bolt nondestructive testing method according to claim 3, characterized in that: The step of installing the excitation device and the receiving device at the detection point includes: Install a fixture at the detection point, and install the excitation device and the receiving device on the fixture; The clamp is provided with a mounting hole, the exposed section is passed through the mounting hole, and the hole wall of the mounting hole is in contact with the exposed section.

6. The anchor bolt nondestructive testing method according to claim 5, characterized in that: An installation plane is provided on the outer wall of the clamp, and the excitation device and the receiving device are installed on the installation plane.

7. The anchor bolt nondestructive testing method according to claim 5, characterized in that: The clamp includes a first part and a second part, the first part and the second part are detachably connected, and the first part and the second part are aligned to form the mounting hole.

8. The anchor bolt nondestructive testing method according to claim 5, characterized in that: The clamp is a carbon steel clamp or an alloy clamp with magnetic adsorption characteristics.

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