A full-field strain measurement system and method for collaborative deformation of an anchor rod and an anchoring body

Abstract

The application discloses a full-field strain measurement system and method for collaborative deformation of an anchor rod and an anchoring body, wherein the measurement system comprises an image acquisition device, a test table, a transparent anchoring body and an anchor rod; the anchor rod is located in the transparent anchoring body; digital speckles are arranged on the anchor rod and in the transparent anchoring body along the axial direction of the anchor rod; the test table is used for collaborative deformation test of the anchor rod and the transparent anchoring body; and the image acquisition device is used for image acquisition of the digital speckles and acquisition of digital speckle images during the collaborative deformation test of the anchor rod and the transparent anchoring body. The full-field strain characteristics during the collaborative deformation of the anchor rod and the transparent anchoring body can be accurately analyzed.

Description

Technical Field

[0001] This invention relates to the field of full-field strain research technology in the process of coordinated deformation of anchor bolts and anchor bodies, and particularly to a full-field strain measurement system and method for coordinated deformation of anchor bolts and anchor bodies. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of infrastructure such as transportation, water conservancy, and energy extraction in my country, underground engineering projects, represented by tunnels, roadways, coal mine excavations, and underground space complexes, are under construction at a rapid pace. Adverse geological conditions such as fractured and weathered rock masses, and rock masses cut by weak structural planes are frequently encountered in engineering construction, often requiring anchor bolt reinforcement. However, the anchoring effect and stability of the anchor body remain pressing issues in support engineering. Therefore, using indoor testing methods to explore the deformation characteristics of anchor bolts under load and to study the strain characteristics of the anchor body around the bolt is crucial for improving existing anchoring schemes, innovating new types of anchor bolts, and determining the stress conditions of anchor bolts.

[0004] Currently, conventional methods for testing anchor bolts and anchor bodies mostly use strain gauges to acquire data, and this method is relatively mature. However, in the experimental process, commonly used methods for testing anchor bolts and anchor bodies have the following problems: ① Traditional experiments studying the stress characteristics of anchor bolts rely on strain gauges to obtain the strain characteristics of a single point on the anchor bolt, and finally use the strain characteristics of a single point to infer the stress characteristics of the entire length of the anchor bolt. This method suffers from low survival rate of measuring elements, poor quality of measurement data, and weak continuity of measurement data; ② In traditional indoor tests, anchor bolts are mostly anchored in concrete blocks. Concrete blocks can simulate rock-like materials for testing, but there is a problem that it is impossible to obtain the full-field strain during the coordinated deformation process of the test block and the anchor bolt. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a full-field strain measurement system and method for the coordinated deformation of anchor bolts and anchor bodies. By setting digital speckle patterns inside the transparent anchor body and on the anchor bolt, and analyzing the digital speckle images during the coordinated deformation of the anchor body and anchor bolt, accurate analysis of the full-field strain characteristics during the coordinated deformation of the anchor bolt and anchor body is achieved.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In the first aspect, a full-field strain measurement system for the coordinated deformation of anchor bolts and anchor bodies is proposed, including an image acquisition device, a test bench, a transparent anchor body and an anchor bolt, with the anchor bolt located inside the transparent anchor body, and digital speckle patterns set on the anchor bolt and inside the transparent anchor body along the anchor bolt axis.

[0008] The test bench is used for conducting synergistic deformation tests on anchor bolts and transparent anchor bodies;

[0009] The image acquisition device is used to acquire digital speckle images during the coordinated deformation test of anchor bolts and transparent anchor bodies.

[0010] Secondly, a full-field strain measurement method for the coordinated deformation of the anchor bolt and the anchor body is proposed, including:

[0011] The anchor bolt with digital speckle is placed in a transparent anchor body with digital speckle.

[0012] A transparent anchor body with anchor bolts was placed on a test bench for a test of the coordinated deformation of the anchor bolts and the transparent anchor body.

[0013] Digital speckle images of the coordinated deformation of the anchor bolt and the transparent anchor solid were acquired using an image acquisition device during the test.

[0014] By analyzing the digital speckle images, the variation trajectory of the digital speckle during the coordinated deformation test of the anchor bolt and the transparent anchor body is obtained, and then the full-field strain characteristics of the anchor body and the anchor bolt during the coordinated deformation process are obtained.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. This invention sets digital speckle patterns on the surface of the anchor rod and inside the transparent anchor body, and sets up an image acquisition device to acquire images of the digital speckle patterns during the coordinated deformation of the anchor rod and the anchor body, records the positional changes of each speckle, and then analyzes the trajectory of the digital speckle patterns during the coordinated deformation of the anchor body and the anchor rod, thereby realizing accurate analysis of the full-field strain characteristics of the anchor rod and the anchor rod during the coordinated deformation.

[0017] 2. This invention directly sets digital speckle patterns inside the anchor body and on the surface of the anchor rod. When acquiring images of the digital speckle patterns, it prevents speckle distortion in the images from affecting the analysis of the overall strain characteristics, thus ensuring the accuracy of the strain characteristic analysis.

[0018] 3. The transparent anchor body of the present invention has multiple planes with digital speckle patterns. The digital speckle patterns on each plane are evenly distributed. All planes with digital speckle patterns intersect, and the intersection line is the axis of the anchor rod. By setting multiple planes with digital speckle patterns and acquiring images of digital speckle patterns in each plane during the coordinated deformation of the anchor rod and the anchor body, the strain characteristics of the anchor rod and the anchor body in the direction perpendicular to the tensile direction can be analyzed by comparing and analyzing the images of digital speckle patterns on different planes during the coordinated deformation of the anchor rod and the anchor body.

[0019] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0021] Figure 1 This is a three-dimensional diagram of the anchor body with anchor bolts in the system disclosed in Example 1;

[0022] Figure 2 The workflow of the system is disclosed in Example 1. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0025] Example 1

[0026] In this embodiment, a full-field strain measurement system for the coordinated deformation of anchor bolt and anchor body is disclosed, including an image acquisition device, a test bench, a transparent anchor body and an anchor bolt, wherein the anchor bolt is located inside the transparent anchor body, and digital speckle patterns are set on the anchor bolt and inside the transparent anchor body along the axial direction of the anchor bolt;

[0027] The test bench is used for conducting synergistic deformation tests on anchor bolts and transparent anchor bodies;

[0028] The image acquisition device is used to acquire digital speckle images during the coordinated deformation test of anchor bolts and transparent anchor bodies.

[0029] The transparent anchor body is made of a transparent rock-like material, possessing both high strength and high transparency. The anchor bolt material can be freely chosen, not limited to steel, carbon fiber, or glass fiber, and can be selected according to the experimental requirements.

[0030] The shape of the anchor bolt can be freely selected, and it is not limited to various shapes such as full-length bonded anchor bolts, expansion shell anchor bolts, self-diving anchor bolts, or inverted wedge anchor bolts.

[0031] The connection relationship between the anchor bolt and the transparent anchor body is as follows: Figure 1 As shown, an anchoring plate 5 is set at one end of the transparent anchor body, one end of the anchor rod 3 is connected to the anchoring plate 5, and the other end extends into the interior of the transparent anchor body. The axis of the anchor rod 3 is perpendicular to one end face of the transparent anchor body, and an anchoring agent is injected between the anchor rod 3 and the transparent anchor body.

[0032] To achieve full-field strain analysis of the coordinated deformation process of the anchor bolt and the anchor body, digital speckle patterns 2 are set on the anchor bolt 3 and inside the anchor body. The setting direction of the digital speckle patterns 2 is the same as that of the anchor bolt axis.

[0033] The digital speckle 2 within the transparent anchor body is located on the plane containing the axis of the anchor rod 3, and the digital speckle 2 is evenly distributed on the plane.

[0034] The length of the area where digital speckle is laid is greater than or equal to the length of anchor bolt 3. The area where digital speckle 2 is laid in the transparent anchor body is the same as the width of the transparent anchor body, that is, the digital speckle is laid to the edge of the transparent anchor body.

[0035] To ensure the accuracy of the digital speckle setting position, the digital speckle and the transparent anchor body are integrally molded. This ensures the accuracy of the digital speckle setting position and prevents any deviation in the position of the digital speckle from affecting the full-field strain characteristic analysis. It also ensures the accuracy of the full-field strain characteristic analysis during the coordinated deformation of the anchor bolt and the anchor body.

[0036] To analyze the strain characteristics of anchor rod 3 and anchor body in the direction perpendicular to the tensile direction during the coordinated deformation of anchor rod 3 and anchor body, digital speckle patterns are set on multiple planes within the transparent anchor body. The digital speckle patterns on each plane are evenly distributed, and all planes with digital speckle patterns intersect, with the intersection line being the axis of anchor rod 3.

[0037] By placing the anchor rod inside the anchor body, and then placing the anchor body with the anchor rod on the test bench, the anchor rod and the anchor body undergo coordinated deformation through the test bench. During the coordinated deformation process, the digital speckle pattern on the anchor rod and the anchor body is acquired through an image acquisition device to obtain digital speckle images. The change position of each speckle in each speckle field is recorded, including the starting position of each speckle, the ending position after the coordinated deformation test, and the trajectory. The position change information of the speckle in the anchor rod and the anchor body is the full-field strain data information of the coordinated deformation during the test.

[0038] Taking the example of a test bench capable of performing tensile tests on an anchor body equipped with anchor bolts, thereby causing the anchor bolts and the anchor body to deform synergistically, the working process of the system disclosed in this embodiment will be described in detail.

[0039] like Figure 2 As shown, 3D printing technology is used to print a transparent anchor body using a transparent rock-like material. The transparent anchor body has a pre-drilled hole for placing the anchor rod 3. The hole is a cylinder. The radius of the bottom surface and the height of the pre-drilled cylinder are determined by the length and diameter of the anchor rod to be tested. However, the pre-drilled space must be larger than the volume of the anchor rod to ensure that the anchor rod can be smoothly inserted and anchored.

[0040] The transparent anchor body includes an upper transparent anchor body 1 and a lower transparent anchor body 6, with a separation layer 4 between the upper transparent anchor body 1 and the lower transparent anchor body 6. It is printed as a whole, and during the printing process, digital speckle 2 is placed at a predetermined position so that the digital speckle and the transparent anchor body are integrally formed. A cutting machine is used to cut the transparent anchor body at the pre-set separation layer 4 to separate the upper transparent anchor body 1 and the lower transparent anchor body 6. Anchor rod 3 is placed into a pre-set hole and anchoring agent is injected so that the anchor rod 3 forms a whole with the upper transparent anchor body 1 and the lower transparent anchor body 6. Finally, the anchoring plate 5 is installed to fix the anchor rod 3.

[0041] The upper part 1 of the transparent anchor body is fixed on the test platform, and the lower part 6 of the transparent anchor body is stretched. The entire stretching process is recorded by an image acquisition device. After the stretching is completed, the trajectory of the digital speckle on the anchor rod and the anchor body can be clearly seen as the stretching process changes. Thus, the full-field strain characteristics of the anchor body and the anchor rod during the coordinated deformation process can be obtained.

[0042] The system disclosed in this embodiment can, in addition to causing the anchor bolt and anchor body to deform synergistically through tensile testing, also perform any test that causes the anchor bolt and anchor body to deform synergistically, such as compression and direct shear, and analyze the full-field strain characteristics of the anchor bolt and anchor body during the synergistic deformation process caused by the test.

[0043] The measurement system disclosed in this embodiment has speckle patterns arranged along the entire length of the anchor rod and inside the transparent anchor body. When conducting the coordinated deformation test of the anchor rod and anchor body, it can obtain the stress and deformation characteristics of the entire length of the anchor rod and the full-field strain during the coordinated deformation process of the anchor body and the anchor rod without the need to place strain gauges. This better reflects the interaction between the anchor rod and the anchor body, greatly simplifies the test process, and provides more comprehensive and accurate measurement results. It solves the problems of existing methods, such as difficulty in obtaining the stress characteristics of the entire length of the anchor rod, poor data quality, weak continuity of measurement data, and inability to obtain the full-field strain during the coordinated deformation process of the anchor body and the anchor rod.

[0044] Example 2

[0045] In this embodiment, a full-field strain measurement method for the coordinated deformation of the anchor bolt and the anchor body is disclosed, including:

[0046] The anchor bolt with digital speckle is placed in a transparent anchor body with digital speckle.

[0047] A transparent anchor body with anchor bolts was placed on a test bench for a test of the coordinated deformation of the anchor bolts and the transparent anchor body.

[0048] Digital speckle images of the coordinated deformation of the anchor bolt and the transparent anchor solid were acquired using an image acquisition device during the test.

[0049] By analyzing the digital speckle images, the variation trajectory of the digital speckle during the coordinated deformation test of the anchor bolt and the transparent anchor body is obtained, and then the full-field strain characteristics of the anchor body and the anchor bolt during the coordinated deformation process are obtained.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A full-field strain measurement system for the coordinated deformation of an anchor bolt and its anchor body, characterized in that, It includes an image acquisition device, a test bench, a transparent anchor body, and an anchor rod. The anchor rod is located inside the transparent anchor body, and digital speckle patterns are set on the anchor rod and inside the transparent anchor body along the anchor rod axis. The test bench is used for conducting synergistic deformation tests on anchor bolts and transparent anchor bodies; The image acquisition device is used to acquire digital speckle images during the coordinated deformation test of the anchor bolt and the transparent anchor body. The digital speckle pattern within the transparent anchor body is located on the plane containing the anchor axis, and the digital speckle pattern on the plane is evenly distributed. The anchor bolt axis is perpendicular to one end face of the transparent anchor body, and the plane containing the digital speckle inside the transparent anchor body is also perpendicular to that end face of the transparent anchor body. Digital speckle patterns are set on multiple planes within the transparent anchor body. The digital speckle patterns on each plane are evenly distributed. All planes with digital speckle patterns intersect, and the line of intersection is the axis of the anchor rod.

2. The full-field strain measurement system for the coordinated deformation of anchor bolts and anchor bodies as described in claim 1, characterized in that, The length of the area where digital speckle patterns are deployed is greater than or equal to the length of the anchor bolt.

3. The full-field strain measurement system for the coordinated deformation of anchor bolts and anchor bodies as described in claim 1, characterized in that, The area in the transparent anchor body where digital speckle patterns are arranged is the same width as the transparent anchor body.

4. The full-field strain measurement system for the coordinated deformation of anchor bolts and anchor bodies as described in claim 1, characterized in that, An anchor plate is installed at one end of the transparent anchor body, one end of the anchor rod is connected to the anchor plate, and the other end extends into the interior of the transparent anchor body.

5. The full-field strain measurement system for the coordinated deformation of anchor bolts and anchor bodies as described in claim 1, characterized in that, Anchoring agent is injected between the anchor bolt and the transparent anchor body.

6. The full-field strain measurement system for the coordinated deformation of anchor bolts and anchor bodies as described in claim 1, characterized in that, Transparent anchor solid and digital speckle are integrally molded.

7. A method for measuring the full-field strain of the coordinated deformation of an anchor bolt and its anchor body, comprising a full-field strain measurement system for the coordinated deformation of an anchor bolt and its anchor body as described in any one of claims 1-6, characterized in that, include: The anchor bolt with digital speckle is placed in a transparent anchor body with digital speckle. A transparent anchor body with anchor bolts was placed on a test bench for a test of the coordinated deformation of the anchor bolts and the transparent anchor body. Digital speckle images of the coordinated deformation of the anchor bolt and the transparent anchor solid were acquired using an image acquisition device during the test. By analyzing the digital speckle images, the variation trajectory of the digital speckle during the coordinated deformation test of the anchor bolt and the transparent anchor body is obtained, and then the full-field strain characteristics of the anchor body and the anchor bolt during the coordinated deformation process are obtained.

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