Anchoring part prestress detection system and method based on wireless passive sensing technology

Abstract

The invention relates to the field of stress detection, and provides an anchoring part prestress detection system and method based on a wireless passive sensing technology in order to realize more convenient and more reliable prestress detection. The detection ring made of the piezoelectric material is arranged between the anchor backing plate and the working anchor of the anchoring part, when prestress is applied to the anchoring part, the piezoelectric material layer and the metal electrodes arranged on the piezoelectric material layer can generate electric signals between the electrodes due to the piezoelectric effect, and the detection ring is used for detecting the voltage of the anchoring part. In the process that the piezoelectric material layer generates periodic elastic deformation, acoustic surface waves can be excited and spread on the surface of the piezoelectric material layer, the signal receiving device converts collected acoustic wave signals into prestress data, and detection of the anchoring prestress of the anchoring part is achieved. The detection system and method have the advantages of being stable, reliable, passive, wireless and convenient.

Description

Technical Field

[0001] The present invention relates to the field of stress detection, and in particular to a system and method for detecting prestress of an anchor based on wireless passive sensing technology. Background Art

[0002] In geotechnical engineering, in order to enhance the stability of slopes or surrounding rocks of underground projects, a large number of prestressed anchors (anchor rods, anchor cables) are used to reinforce them. However, the anchors are buried in the rock and soil, and the grouting in the anchor holes is a hidden project. Therefore, whether the prestressed anchors can effectively form a reinforcement effect on the slope requires prestressed reinforcement testing.

[0003] In the prior art, the prestress detection of anchors is usually measured by the back-pull method, strain gauge and fiber Bragg grating method. Since the use environment of prestressed anchors is mostly complex geological conditions, the device for detecting their prestress needs to maintain good working performance in harsh environments. However, there are certain defects in the use of the back-pull method, strain gauge or fiber Bragg grating method for prestress detection of anchors.

[0004] During the process of detecting prestress by the reverse tension method, relative displacement between the jack tool clip and the prestressed tendons is likely to occur, causing the turning point to appear prematurely. In this way, the accuracy of the test results cannot be effectively guaranteed. At the same time, this method will over-tension the original anchor prestress, which may damage the working clip and destroy the prestressed state of the original anchoring system, causing major safety hazards.

[0005] The strain gauge detection method is to install strain gauges on the anchors and calculate the stress value of each monitoring point according to the elastic modulus of the anchors. However, the temperature stability of the strain gauges is poor and the sensitivity dispersion is large. At the same time, since the strain gauges are under high stress for a long time, static fatigue fracture may occur and they are very easy to be damaged in actual construction.

[0006] The fiber Bragg grating detection method calculates strain based on the relationship between tension and strain to obtain the prestress value. Its disadvantage is that temperature compensation must be performed when measuring strain, which may not be met in actual construction. When installing the fiber Bragg grating on the anchor, it is generally necessary to cut a groove, and this operation will affect the strength of the anchor and the safety of the structure. At the same time, the fiber Bragg grating is relatively fragile and is very easy to break during use. It is extremely inconvenient to install in underground projects such as tunnels, and it is expensive, making it impossible to carry out large-scale full-area detection.

[0007] In summary, in the anchor quality inspection of anchoring pieces, the existing methods have great limitations, and are cumbersome to operate and expensive. It is urgent to propose a fast, effective and reliable anchor prestress inspection system and method. Summary of the invention

[0008] In order to achieve more convenient and reliable prestress detection, the present application provides an anchor prestress detection system and method based on wireless passive sensing technology.

[0009] The technical solution adopted by the present invention to solve the above problems is:

[0010] The anchor prestress detection system based on wireless passive sensing technology includes: a detection ring and a signal receiving and processing device. The detection ring includes a piezoelectric material that can excite sound waves and electrodes arranged on both sides of the piezoelectric material. The signal receiving and processing device receives the sound wave signal and converts the sound wave signal into corresponding prestress data according to the conversion relationship between the sound wave signal and the prestress.

[0011] Furthermore, a reflective layer is arranged outside the electrode.

[0012] Furthermore, the anchoring member is an anchor rod or an anchor cable.

[0013] Furthermore, the anchoring member comprises an anchor plate and a working anchor, and the detection ring is installed between the anchor plate and the working anchor.

[0014] Furthermore, it also includes a display device for displaying prestress data.

[0015] The invention discloses an anchor prestress detection method based on wireless passive sensing technology, which is applied to an anchor prestress detection system based on wireless passive sensing technology, and comprises: installing a detection ring on the anchor, applying prestress in the anchor, using a signal receiving and processing device to receive an acoustic wave signal and converting the acoustic wave signal into corresponding prestress data according to a conversion relationship between the acoustic wave signal and the prestress.

[0016] Furthermore, the anchoring member is an anchor rod or an anchor cable.

[0017] Furthermore, the anchoring member comprises an anchor plate and a working anchor, and the detection ring is installed between the anchor plate and the working anchor.

[0018] Compared with the prior art, the present invention has the following beneficial effects: by arranging a detection ring made of piezoelectric material between the anchor pad and the working anchor of the anchor, when prestress is applied in the anchor, the piezoelectric material layer and the metal electrode arranged on the piezoelectric material layer will generate an electrical signal between the electrodes due to the piezoelectric effect, and the piezoelectric material layer will generate periodic elastic deformation process, which will excite surface acoustic waves and propagate on the surface of the piezoelectric material layer. The signal receiving device converts the collected acoustic wave signal into prestress data, thereby realizing the detection of anchor prestress. The detection system and method have the advantages of stability, reliability, passive wireless and convenience. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the detection ring structure;

[0020] Figure 2 It is a schematic diagram of the cross section of the detection ring;

[0021] Figure 3 This is a schematic diagram of the installation position of the detection ring;

[0022] Figure numerals: 1 is surrounding rock; 2 is anchor rod; 3 is anchor end; 4 is anchor pad; 5 is working anchor; 6 is detection ring; 7 is reflection layer; 8 is electrode; 9 is piezoelectric material. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] The anchor prestress detection system based on wireless passive sensing technology includes: a detection ring and a signal receiving and processing device, such as Figure 1 , Figure 2 As shown, the detection ring includes a piezoelectric material 9 that can excite sound waves and electrodes 8 arranged on both sides of the piezoelectric material 9. The signal receiving and processing device includes an input matching network, an automatic frequency sweeping module, a surface acoustic wave resonator, and an acoustic wave conversion module that converts the acoustic wave signal into corresponding prestress data according to the conversion relationship between the acoustic wave signal and the prestress. The anchor can be an anchor rod or an anchor cable, and the piezoelectric material is ZnO or AlN.

[0025] In the process of applying prestress in the anchor, the stress is converted into an electrical signal based on the detection ring, and then the electrical signal is converted into an acoustic wave signal. The signal receiving and processing device receives the acoustic wave signal and converts the acoustic wave signal into corresponding prestress data based on the conversion relationship between the acoustic wave signal and the prestress.

[0026] Take anchor rod as an example. Figure 3 As shown, 1 is surrounding rock, 2 is anchor rod, 3 is anchor end, 4 is anchor pad, 5 is working anchor, 6 is detection ring, and in this embodiment, detection ring 6 is arranged between anchor pad 4 and working anchor 5. In order to improve the receiving amount of acoustic wave signal received by the receiving and processing device, a reflection layer 7 is also arranged outside the electrode 8 close to the surrounding rock 1. In order to facilitate timely acquisition of prestress data, a display device for displaying prestress data is also arranged.

[0027] When prestress is applied in the anchor, the piezoelectric material layer can excite an acoustic wave signal. The signal receiving and processing device receives the acoustic wave signal and converts the acoustic wave signal into corresponding prestress data based on the conversion relationship between the acoustic wave signal and the prestress, thereby realizing the detection of the anchor prestress.

[0028] The invention discloses an anchor prestress detection method based on wireless passive sensing technology, which is applied to an anchor prestress detection system based on wireless passive sensing technology, and comprises: installing a detection ring on the anchor, and in the process of applying prestress in the anchor, using a signal receiving and processing device to receive an acoustic wave signal and converting the acoustic wave signal into corresponding prestress data according to the conversion relationship between the acoustic wave signal and the prestress.

[0029] When using the detection system of the present application for stress detection, it is only necessary to set the detection ring between the anchor plate and the working anchor. It is easy to use and uses wireless passive sensing technology for signal collection. It has the advantages of being economical, fast, simple and highly accurate.

Claims

1. Anchor prestress detection system based on wireless passive sensing technology, characterized in that: include: The detection ring and the signal receiving and processing device include a piezoelectric material that can excite sound waves and electrodes arranged on both sides of the piezoelectric material. The signal receiving and processing device receives the sound wave signal and converts the sound wave signal into corresponding prestress data according to the conversion relationship between the sound wave signal and the prestress.

2. The anchor prestress detection system based on wireless passive sensing technology according to claim 1 is characterized in that: A reflective layer is also arranged on the outside of the electrode.

3. The anchor prestress detection system based on wireless passive sensing technology according to claim 1 is characterized in that: The anchoring member is an anchor rod or an anchor cable.

4. The anchor prestress detection system based on wireless passive sensing technology according to claim 3 is characterized in that: The anchoring piece comprises an anchor pad and a working anchor, and the detection ring is installed between the anchor pad and the working anchor.

5. The anchor prestress detection system based on wireless passive sensing technology according to any one of claims 1 to 4, characterized in that: Also included is a display device for displaying prestress data.

6. An anchor prestress detection method based on wireless passive sensing technology, applied to an anchor prestress detection system based on wireless passive sensing technology as claimed in any one of claims 1 to 5, characterized in that: include: The detection ring is installed on the anchor, prestress is applied in the anchor, and the signal receiving and processing device is used to receive the acoustic wave signal and convert the acoustic wave signal into corresponding prestress data according to the conversion relationship between the acoustic wave signal and the prestress.

7. The anchor prestress detection method based on wireless passive sensing technology according to claim 6 is characterized in that: The anchoring member is an anchor rod or an anchor cable.

8. The anchor prestress detection method based on wireless passive sensing technology according to claim 7 is characterized in that: The anchoring piece comprises an anchor pad and a working anchor, and the detection ring is installed between the anchor pad and the working anchor.

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