Clamp suitable for sample crack monitoring in true triaxial experiment process

Abstract

The utility model relates to a clamp suitable for monitoring a sample crack in a true triaxial experiment process, which comprises a transparent acrylic organic glass plate, the transparent acrylic organic glass plate and a solid iron block II are respectively and fixedly mounted in front of and behind a solid iron block I, and a through hole is formed in the middle of the solid iron block I for mounting an ultra-wide-angle camera. A third cutting groove communicated with the through hole is formed in the upper portion of the first solid iron block, a first cutting groove and a second cutting groove are formed in the two sides of the third cutting groove respectively, a first acoustic emission probe is arranged at the bottom of the first cutting groove, a second acoustic emission probe is arranged at the bottom of the second cutting groove, and a third spring enables the ultra-wide-angle camera to be attached to the transparent acrylic organic glass plate. By means of the characteristics of high compressive strength and transparency of acrylic organic glass, a clamping block of a triaxial press is changed into a combination of a transparent acrylic organic glass plate and an iron block, an ultra-wide-angle camera is arranged between the iron block and glass and is matched with a high-frequency camera, and meanwhile, an acoustic emission probe is embedded into a glass surface in contact with a test block, so that the test block is detected. The problem of crack monitoring of the triaxial test block is solved.

Description

Technical Field

[0001] This utility model relates to an experimental fixture, specifically a fixture suitable for monitoring specimen cracks during true triaxial experiments. Background Technology

[0002] Engineering disturbances such as blasting, loading, excavation, and unloading will cause new fractures to form in the surrounding rock, which will adversely affect the mechanical properties of the rock mass. True triaxial tests can simulate the triaxial stress state of underground rock and analyze the changes in parameters such as stress, displacement, and fracture propagation during loading and unloading. This has important theoretical significance and engineering application value for studying the mechanical properties of coal and rock.

[0003] Existing true triaxial loading tests use six-directional clamps to completely enclose the sample, making it impossible to directly observe the evolution of fractures in the coal and rock mass during loading and unloading. Some approaches attempt to address fracture research using transparent rocks; however, transparent rocks are not part of the strata coal and rock mass and their properties differ. Other approaches use CT scans of the sample before and after the test to compare and analyze fracture development characteristics, but this method cannot effectively and continuously monitor the fracture evolution process. Still other approaches embed acoustic emission probes within the clamps to locate fractures and infer their evolution through acoustic emission signals; however, the accuracy of acoustic emission location is affected by parameters such as wave velocity, and the location accuracy needs to be corrected based on the actual fracture morphology, all of which have shortcomings in practical use. Utility Model Content

[0004] To address the problems existing in the prior art, this utility model provides a fixture suitable for monitoring specimen cracks during true triaxial experiments, which can monitor the evolution characteristics of specimen cracks during experiments under true triaxial stress conditions.

[0005] To achieve the above objectives, this utility model provides a fixture for monitoring sample cracks during a true triaxial experiment. It includes a transparent acrylic glass plate, a solid iron block one, and a solid iron block two. The transparent acrylic glass plate and the solid iron block two are fixedly mounted at the front and rear of the solid iron block one, respectively. A through hole is opened in the middle of the solid iron block one to mount an ultra-wide-angle camera. A groove three is opened on the upper part of the solid iron block one, connecting to the through hole. Grooves one and two are opened on both sides of groove three, respectively. An acoustic emission probe one is installed at the bottom of groove one, and an acoustic emission probe two is installed at the bottom of groove two. A spring three keeps the ultra-wide-angle camera in contact with the transparent acrylic glass plate.

[0006] In addition, the fixture for monitoring specimen cracks during true triaxial experiments proposed in the above embodiments of this utility model may also have the following additional technical features:

[0007] As a further improvement of this utility model, the rear part of the acoustic emission probe one is connected to PVD cylinder one and spring one in sequence, and the rear part of the acoustic emission probe two is connected to PVD cylinder two and spring two in sequence.

[0008] As a further improvement of this utility model, the acoustic emission probe wire one of the acoustic emission probe one is thrown out from the first groove, and the acoustic emission probe wire two of the acoustic emission probe two is thrown out from the second groove.

[0009] As a further improvement of this utility model, the ultra-wide-angle camera line of the ultra-wide-angle camera is ejected from the three slots.

[0010] As a further improvement of this utility model, the transparent acrylic organic glass plate is fixedly installed at the front of the solid iron block one by bolts one, two, three and four, and the solid iron block two is installed at the rear of the solid iron block one by bolts five, six, seven and eight.

[0011] By means of the above solution, this utility model has at least the following advantages: by taking advantage of the high compressive strength and transparency of acrylic plexiglass, the clamping block of the triaxial press is changed into a combination of transparent acrylic plexiglass plate and iron block. An ultra-wide-angle camera is placed between the iron block and the glass, in conjunction with a high-frequency camera. At the same time, an acoustic emission probe is embedded inside the glass surface in contact with the test block, thus solving the problem of crack monitoring of the triaxial test block. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the three-dimensional structure of a fixture suitable for monitoring specimen cracks during true triaxial experiments;

[0013] Figure 2 This is the front view of a fixture suitable for monitoring specimen cracks during true triaxial experiments;

[0014] Figure 3 This is a side view of a fixture suitable for monitoring specimen cracks during true triaxial experiments;

[0015] Figure 4 This is a top view of a fixture suitable for monitoring specimen cracks during true triaxial experiments;

[0016] Figure 5 This is a rear view of a fixture suitable for monitoring specimen cracks during true triaxial experiments;

[0017] In the picture: 1. Transparent acrylic sheet, 2. Solid iron block one, 3. Solid iron block two, 4. Ultra-wide-angle camera, 5. Acoustic emission probe one, 6. Acoustic emission probe two, 7. PVD cylinder one, 8. PVD cylinder two, 9. Spring one, 10. Spring two, 11. Spring three, 12. Ultra-wide-angle camera cable, 13. Acoustic emission probe cable one, 14. Acoustic emission probe cable two, 15. Groove one, 16. Groove two, 17. Groove three, 18. Bolt one, 19. Bolt two, 20. Bolt three, 21. Bolt four, 22. Bolt five, 23. Bolt six, 24. Bolt seven, 25. Bolt eight. Detailed Implementation

[0018] The following description, in conjunction with the accompanying drawings, describes the fixture of this invention for monitoring specimen cracks during true triaxial experiments.

[0019] In Embodiment 1 of this application, as Figures 1 to 5 As shown, this fixture (hereinafter referred to as "the present invention") is suitable for monitoring specimen cracks during true triaxial experiments. In true triaxial experiments, stress loading is achieved by combining six fixtures. Each fixture structure is designed to integrate the specimen crack monitoring function. That is, the fixture protected by this utility model is a special fixture for monitoring specimen cracks during true triaxial experiments. It includes a transparent acrylic plexiglass plate 1, a solid iron block 1 2, a solid iron block 2 3, and an ultra-wide-angle camera 4. The transparent acrylic plexiglass plate 1 and the solid iron block 2 3 are fixedly installed at the front and rear of the solid iron block 1 2, respectively. The ultra-wide-angle camera 4 is installed in the middle of the solid iron block 1 2 through hole. The upper part of the solid iron block 1 2 has a groove 3 17 connecting the through hole. The groove 3 17 has groove 1 15 and groove 2 16 on both sides. The bottom of groove 1 15 is provided with an acoustic emission probe 1 5, and the bottom of groove 2 16 is provided with an acoustic emission probe 2 6. Spring 3 11 makes the ultra-wide-angle camera 4 fit against the transparent acrylic plexiglass plate 1. A transparent acrylic sheet 1 contacts the sample, transmitting compressive stress and transparently displaying surface cracks. Solid iron blocks 2 and 3 are fixed to the transparent acrylic sheet 1 to bear complex stresses during the test and ensure the sample's load-bearing capacity. An ultra-wide-angle camera 4 is used to capture the evolution of cracks in the sample; acoustic emission probes 5 and 6 are used to monitor the sample's fracture signals.

[0020] To further optimize the working efficiency of this application and to better fit the acoustic emission probe 5 and acoustic emission probe 6 to the transparent acrylic sheet 1, the rear of acoustic emission probe 5 is sequentially connected to a PVD cylinder 7 and a spring 9, and the rear of acoustic emission probe 6 is sequentially connected to a PVD cylinder 8 and a spring 10. To facilitate the wiring of the ultra-wide-angle camera cable 12, acoustic emission probe cable 13, and acoustic emission probe cable 14, acoustic emission probe cable 13 of acoustic emission probe 5 extends from slot 15, and acoustic emission probe cable 14 of acoustic emission probe 6 extends from slot 16 and is connected to the high-frequency camera. The ultra-wide-angle camera cable 12 of the ultra-wide-angle camera 4 extends from slot 17 and is connected to the high-frequency camera. For ease of assembly, the transparent acrylic plexiglass plate 1 is fixedly installed at the front of the solid iron block 2 by bolts 18, 19, 20 and 21, and the solid iron block 23 is installed at the rear of the solid iron block 2 by bolts 22, 23 and 24 and 25.

[0021] When using this equipment, install the fixture suitable for monitoring specimen cracks during true triaxial experiments. After installation, connect the corresponding lines, and the equipment can be put into use.

[0022] When this utility model is used, its specific operation is as follows:

[0023] The six fixtures used in the true triaxial experiment were assembled, and the fixtures were placed on the triaxial testing machine to carry out the true triaxial experiment. A high-frequency camera was used to record the dynamic development of surface cracks on the specimen in real time during the experiment. Acoustic emission probe 5 and acoustic emission probe 6 were used to continuously collect and record the signals generated by the specimen fracture. By analyzing the location of the acoustic emission signals, the fracture morphology inside the specimen was initially constructed. Then, the data was corrected by combining the surface crack features captured by the ultra-wide-angle camera 4, and finally, the three-dimensional fracture features of the specimen during the true triaxial experiment were accurately constructed.

[0024] In summary, the fixture for monitoring specimen cracks in a true triaxial experiment, according to this embodiment of the invention, utilizes the high compressive strength and transparency of the transparent acrylic plexiglass plate 1. The triaxial press clamp is modified into a combination of a transparent acrylic plexiglass plate and an iron block. An ultra-wide-angle camera is placed between the iron block and the glass, along with a high-frequency camera. At the same time, an acoustic emission probe is embedded inside the glass surface in contact with the specimen, thus solving the problem of crack monitoring in triaxial specimens.

[0025] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity. Any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A fixture suitable for monitoring the fracture of a sample during tri-axial testing, comprising a solid iron block (2), characterised in that, The solid iron block 1 (2) is fixedly installed with a transparent acrylic organic glass plate (1) and a solid iron block 2 (3) at the front and back respectively. A through hole is opened in the middle of the solid iron block 1 (2) to install an ultra-wide-angle camera (4). A groove 3 (17) is opened on the upper part of the solid iron block 1 (2) to connect the through hole. A groove 1 (15) and a groove 2 (16) are opened on both sides of the groove 3 (17). An acoustic emission probe 1 (5) is set at the bottom of the groove 1 (15), and an acoustic emission probe 2 (6) is set at the bottom of the groove 2 (16). A spring 3 (11) makes the ultra-wide-angle camera (4) fit against the transparent acrylic organic glass plate (1).

2. The fixture for monitoring specimen cracks during true triaxial experiments according to claim 1, characterized in that, The acoustic emission probe 1 (5) is connected in sequence to PVD cylinder 1 (7) and spring 1 (9) at the rear, and the acoustic emission probe 2 (6) is connected in sequence to PVD cylinder 2 (8) and spring 2 (10) at the rear.

3. The fixture for monitoring specimen cracks during true triaxial experiments according to claim 2, characterized in that, The acoustic emission probe line 1 (13) of the acoustic emission probe 1 (5) is thrown out from the first groove (15), and the acoustic emission probe line 2 (14) of the acoustic emission probe 2 (6) is thrown out from the second groove (16).

4. The fixture for monitoring specimen cracks during true triaxial experiments according to claim 1, characterized in that, The ultra-wide-angle camera line (12) of the ultra-wide-angle camera (4) is ejected from the slot three (17).

5. The fixture for monitoring specimen cracks during true triaxial experiments according to claim 4, characterized in that, The transparent acrylic organic glass plate (1) is fixedly installed on the front of the solid iron block one (2) by bolt one (18), bolt two (19), bolt three (20) and bolt four (21), and the solid iron block two (3) is installed on the rear of the solid iron block one (2) by bolt five (22), bolt six (23), bolt seven (24) and bolt eight (25).

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