Anchoring part prestress detection system based on wireless passive sensing technology

Abstract

The utility model relates to the field of stress detection, and provides an anchoring part prestress detection system 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 utility model relates to the field of stress detection, in particular to an anchor prestress detection system based on wireless passive sensing technology. Background Art

[0002] In geotechnical engineering, prestressed anchors (anchor rods and cables) are widely used to reinforce slopes or surrounding rock in underground projects to enhance their stability. However, anchors are buried within the rock and soil, and grouting in the anchor holes is a concealed project. Therefore, whether prestressed anchors can effectively reinforce the slope requires prestressed reinforcement testing.

[0003] In existing technologies, anchor prestress is typically measured using the back-pull method, strain gauges, and fiber Bragg grating (FBG) methods. Because prestressed anchors are often used in complex geological environments, the devices used to measure prestress must be able to maintain good performance in harsh environments. However, these methods, including back-pull, strain gauges, and FBG, all have drawbacks.

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

[0005] The strain gauge detection method is to install strain gauges on the anchor and calculate the stress value of each monitoring point based on the elastic modulus of the anchor. However, the temperature stability of the strain gauge is poor and its sensitivity is highly discrete. At the same time, since the strain gauge is under high stress for a long time, static fatigue fracture may occur and it is 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, thereby deriving 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 grooves, and this operation will affect the strength of the anchor and affect the safety of the structure. At the same time, the fiber Bragg grating is relatively fragile and easily breaks 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 anchoring quality inspection of anchoring pieces, the existing methods have great limitations, are cumbersome to operate, and are expensive. It is urgent to propose a fast, effective and reliable anchor prestressing inspection system and method. Utility Model Content

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

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

[0010] An 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 based on the conversion relationship between the sound wave signal and the prestress.

[0011] Furthermore, a reflective layer is provided on the outside of the electrode.

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

[0013] Furthermore, the anchoring member includes 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] Compared to existing technologies, the present invention has the following advantages: by placing a detection ring made of piezoelectric material between the anchor plate and the working anchor of the anchor, when prestress is applied to the anchor, the piezoelectric material layer and the metal electrodes arranged on the piezoelectric material layer generate electrical signals between the electrodes due to the piezoelectric effect. During the periodic elastic deformation of the piezoelectric material layer, surface acoustic waves are excited and propagated on the surface of the piezoelectric material layer. The signal receiving device converts the collected acoustic wave signals into prestress data, thereby realizing the detection of the anchor prestress. The detection system and method are stable, reliable, passive, wireless, and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the detection ring structure;

[0017] Figure 2 Schematic diagram of the cross section of the detection ring;

[0018] Figure 3 This is a schematic diagram of the installation position of the detection ring;

[0019] Figure numerals: 1 is surrounding rock; 2 is anchor rod; 3 is anchoring 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

[0020] In order to make the purpose, technical solutions 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 intended to limit the present invention.

[0021] 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 piezoelectric material 9 that can excite acoustic waves and electrodes 8 disposed on either side of the piezoelectric material 9. The signal receiving and processing device includes an input matching network, an automatic frequency sweep module, a surface acoustic wave resonator, and an acoustic wave conversion module that converts the acoustic wave signal into corresponding prestress data based on the conversion relationship between the acoustic wave signal and prestress. The anchor can be an anchor rod or an anchor cable, and the piezoelectric material is ZnO or AlN.

[0022] During 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.

[0023] Take anchor rod as an example. Figure 3 As shown, 1 is the surrounding rock, 2 is the anchor rod, 3 is the anchor end, 4 is the anchor plate, 5 is the working anchor, and 6 is the detection ring. In this embodiment, the detection ring 6 is arranged between the anchor plate 4 and the working anchor 5. To improve the reception of acoustic wave signals by the receiving and processing device, a reflective layer 7 is also provided outside the electrode 8 near the surrounding rock 1. To facilitate timely acquisition of prestress data, a display device for displaying prestress data is also provided.

[0024] 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.

[0025] An anchor prestress detection method based on wireless passive sensing technology is applied to an anchor prestress detection system based on wireless passive sensing technology, including: 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 based on the conversion relationship between the acoustic wave signal and the prestress.

[0026] The stress detection system is used for stress detection, and only needs to be sleeved between the anchor pad and the working anchor, is convenient to use, uses wireless passive sensing technology for signal collection, and has the advantages of economy, rapidness, simplicity, high accuracy and the like.

Claims

1. Anchor prestress detection system based on wireless passive sensing technology, characterized by: 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 based on 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 provided 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 piece 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 plate and a working anchor, and the detection ring is installed between the anchor plate 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 prestressing data.

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