Test mold for fracture toughness test of mine filling body

Abstract

The utility model discloses a test die for fracture toughness test of mine filling body, which comprises a lower die holder and a test die cylinder, the top of the lower die holder is provided with a groove in close fit with the bottom end of the test die cylinder, the test die cylinder consists of two semicircular cylinders, one semicircular cylinder is enclosed by an arc-shaped plate and a T-shaped plate, and the other semicircular cylinder is enclosed by an arc-shaped plate and a T-shaped plate. The other semi-cylinder body is defined by an arc-shaped plate and a Y-shaped plate; and the annular component is used for clamping the top of the test mold cylinder. The utility model solves the problems that the fracture of the test piece is fractured and the test result is inaccurate due to the secondary processing and cutting of the test piece.

Description

Technical Field

[0001] The utility model relates to the technical field of mine filling mining, in particular to a test mold for a mine filling body fracture toughness test. Background Art

[0002] Downward-fill mining is an effective method for coping with high tectonic stresses and surrounding rock fragmentation. This method uses the backfill as a roof, with mining personnel and equipment operating beneath it. This effectively prevents roof failures in unstable orebody conditions. The backfill fracture toughness test, conducted by performing three-point bending tests on specimens containing pre-existing cracks, measures the fracture toughness and the propagation of both mode-I (opening) and mode-II (slip) cracks. Compared to measuring backfill strength, this method more directly reflects the stability of the backfill under roof conditions.

[0003] Fracture toughness testing equipment requires a semi-cylindrical specimen with a crack, while existing molds produce cylindrical specimens. Therefore, the resulting specimens require secondary processing to cut them into semi-cylindrical specimens and create the cracks required for testing. This method has the following drawbacks: First, the secondary cutting process can cause fractures at the prefabricated cracks; second, even if a complete specimen is obtained after secondary processing, vibrations generated during processing can affect the specimen's integrity, leading to inaccurate fracture toughness test results. Utility Model Content

[0004] The utility model provides a test die for a mine filling fracture toughness test, which aims to solve the problems of fracture at the crack of the test piece and inaccurate test results caused by secondary processing and cutting of the test piece.

[0005] The technical solution of this utility model is as follows:

[0006] A test mold for testing the fracture toughness of mine fillings includes a lower mold base and a test mold cylinder. The top of the lower mold base is provided with a groove that tightly fits with the bottom end of the test mold cylinder. The test mold cylinder consists of two semi-cylinders, one semi-cylinder is formed by an arc plate and a T-shaped plate, and the other semi-cylinder is formed by an arc plate and a Y-shaped plate; it also includes an annular component that tightly fits with the upper end of the test mold cylinder to make the two semi-cylinders fit tightly together.

[0007] Furthermore, the T-shaped plate includes a first baffle and a first slit plate perpendicular to the inner wall of the first baffle, the two ends of the first baffle are used to contact and cooperate with the two ends of the corresponding arc plate, and the length of the first slit plate is less than the radius length of the semi-cylinder; the Y-shaped plate includes a second baffle and a second slit plate obliquely connected to the second baffle, and the angle range is 40° to 60°. The two ends of the second baffle are used to contact and cooperate with the two ends of the corresponding arc plate, and the length of the second slit plate is less than the radius length of the semi-cylinder.

[0008] Preferably, the length of the first slot plate is 1 / 2 of the radius of the semi-cylinder; the length of the second slot plate is 1 / 2 of the radius of the semi-cylinder.

[0009] Preferably, the included angle between the second baffle and the second slit plate is 46°.

[0010] Furthermore, a limiting structure for tightly engaging with the annular component is provided on the upper portion of the arc-shaped plate.

[0011] Preferably, the lower mold base, arc-shaped plate, T-shaped plate, Y-shaped plate and annular component are all made of acrylic material.

[0012] Compared with the prior art, the present invention has the following positive effects:

[0013] (1) The test piece made by the utility model is integrally formed with cracks and does not require secondary processing. Its integrity and data accuracy are higher than those of the existing processing method, and its fracture toughness can be more accurately characterized.

[0014] (2) The test mold of this utility model can select the corresponding prefabricated partition plate - T-shaped plate or Y-shaped plate according to the needs, which is suitable for test pieces with different crack shapes.

[0015] (3) This device can simultaneously cast two test specimens with prefabricated gaps that meet the test requirements, optimizing the processing and manufacturing process and improving work efficiency.

[0016] (4) The main body of the utility model is made of acrylic, which has the advantages of being wear-resistant, smooth and easy to demould. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of the utility model.

[0018] Figure 2 This is a schematic diagram of the test mold cylinder structure of the utility model.

[0019] Explanation of the accompanying drawings: 1. Arc-shaped plate; 1-1. Limiting structure; 2. T-shaped plate; 2-1. First slit plate; 2-2. First baffle; 3. Y-shaped plate; 3-1. Second slit plate; 3-2. Second baffle; 4. Annular component; 5. Lower mold base. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the embodiments described are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0021] like Figure 1 The present invention discloses a test mold for testing the fracture toughness of mine fillings. The mold comprises a test mold cylinder and a lower mold base 5. The lower mold base 5 has a groove at the top that fits tightly with the bottom of the test mold cylinder. The test mold cylinder is composed of two semi-cylinders. The test mold also includes an annular component 4 that fits tightly with the top of the test mold cylinder. This component, together with the groove at the top of the lower mold base 5, maintains the stability of the test mold structure and prevents slurry leakage during the pouring process.

[0022] The semi-cylindrical body is formed by the arc plate 1 and the prefabricated partition. Figure 2 , the prefabricated partition includes a T-shaped plate 2 and a Y-shaped plate 3. One semi-cylinder is enclosed by an arc-shaped plate 1 and a T-shaped plate 2, and the other semi-cylinder is enclosed by an arc-shaped plate 1 and a Y-shaped plate 3. The T-shaped plate 2 includes a first baffle 2-2 and a first slit plate 2-1 perpendicular to the inner wall of the first baffle 2-2, and the length of the first slit plate 2-1 is less than the radius length of the semi-cylinder. Preferably, the length of the first slit plate 2-1 is 1 / 2 of the radius length of the semi-cylinder. The Y-shaped plate 3 includes a second baffle 3-2 and a second slit plate 3-1 obliquely connected to the second baffle 3-2, and the angle between the two is 40° to 60°. The length of the second slit plate 3-1 is less than the radius length of the semi-cylinder. Preferably, the length of the second slit plate 3-1 is 1 / 2 of the radius length of the semi-cylinder. The angle between the second slit plate 3-1 and the second baffle 3-2 is 46°.

[0023] Further preferably, the lower mold base 5, the arc-shaped plate 1, the T-shaped plate 2, the Y-shaped plate 3 and the annular component 4 of the present invention are all made of a lightweight and wear-resistant acrylic material, and the surface thereof is smooth for easy demoulding.

[0024] During use, the two semi-cylinders are tightly fitted into the grooves at the top of the lower mold base 5, and the annular component 4 is fixed to the top of the test mold cylinder. Next, a slurry made by mixing tailings, water, and cementitious material is poured into the test mold cylinder. After the slurry solidifies, the annular component 4 is removed, the prefabricated partition is separated from the curved plate 1, and the test piece is removed. The test piece thus produced is integrally formed and has prefabricated gaps, eliminating the need for secondary processing and providing more accurate test results.

[0025] This test mold allows for the selection of prefabricated partitions as needed. The T-shaped plate 2 is used to cast specimens for testing Mode I (opening) cracks, while the Y-shaped plate 3 is used to cast specimens for testing Mode II (slipping) cracks. This device allows for simultaneous casting of two specimens with prefabricated gaps that meet test requirements, optimizing the manufacturing process and improving work efficiency.

[0026] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. The scope of the present invention is defined by the claims rather than the above description.

Claims

1. A test mold for a fracture toughness test of a mine filling body, comprising a lower mold base (5) and a test mold cylinder, characterized in that: The top of the lower mold base (5) is provided with a groove that is tightly matched with the bottom end of the test mold cylinder. The test mold cylinder is composed of two semi-cylindrical bodies, one semi-cylindrical body is formed by enclosing an arc plate (1) and a T-shaped plate (2), and the other semi-cylindrical body is formed by enclosing an arc plate (1) and a Y-shaped plate (3); and it also includes an annular component (4) that is tightly matched with the upper end of the test mold cylinder and is used to make the two semi-cylindrical bodies fit tightly together.

2. The test mold for fracture toughness testing of mine fillings according to claim 1, characterized in that: The T-shaped plate (2) comprises a first baffle (2-2) and a first slot plate (2-1) perpendicular to the inner wall of the first baffle (2-2), the two ends of the first baffle (2-2) being used for contacting and matching with the two ends of the corresponding arc-shaped plate (1), and the length of the first slot plate (2-1) being less than the radius length of the semi-cylinder; the Y-shaped plate (3) comprises a second baffle (3-2) and a second slot plate (3-1) obliquely connected to the second baffle (3-2), the included angle range of which is 40° to 60°, the two ends of the second baffle (3-2) being used for contacting and matching with the two ends of the corresponding arc-shaped plate (1), and the length of the second slot plate (3-1) being less than the radius length of the semi-cylinder.

3. The test mold for fracture toughness testing of mine fillings according to claim 2, characterized in that: The length of the first slit plate (2-1) is 1 / 2 of the radius of the semi-cylinder; the length of the second slit plate (3-1) is 1 / 2 of the radius of the semi-cylinder.

4. The test mold for fracture toughness testing of mine fillings according to claim 2, characterized in that: The included angle between the second baffle (3-2) and the second slit plate (3-1) is 46°.

5. The test mold for fracture toughness testing of mine fillings according to claim 1, characterized in that: The upper portion of the arc-shaped plate (1) is provided with a limiting structure (1-1) for tightly engaging with the annular component (4).

6. The test mold for fracture toughness testing of mine fillings according to claim 1, characterized in that: The lower die base (5), the arc-shaped plate (1), the T-shaped plate (2), the Y-shaped plate (3) and the annular component (4) are all made of acrylic material.

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