A mold and method for preparing samples of specific densities for triaxial compression testing.

Abstract

This application relates to a mold for preparing samples of specific densities for triaxial compression testing, belonging to the field of geotechnical engineering sample preparation devices. It includes a clamping assembly with a forming component inside. A pressure-applying component is slidably connected to the clamping assembly, with its bottom end extending into the forming component to apply pressure to the sample located inside. A functional ring is provided at the end of the clamping assembly, abutting against the end of the clamping assembly. This application simplifies the operation process, improves the efficiency and safety of sample removal, and enables more efficient and accurate sample preparation, thereby improving the quality and efficiency of triaxial compression testing.

Description

Technical Field

[0001] This application relates to the field of geotechnical engineering testing apparatus, and in particular to a set of molds and methods for preparing test samples of a specific density for triaxial compression testing. Background Technology

[0002] Triaxial compression testing is a standard method for investigating the mechanical properties of soil and rock materials, and its results are of crucial value for the design and analysis of geological engineering projects. To ensure the accuracy and reliability of the test results, samples of a specific density must be prepared to simulate actual geological conditions. In traditional preparation processes, soil is typically compressed to a predetermined density using a uniaxial compressor, and then the compacted sample is placed in a triaxial instrument for testing. However, there are numerous triaxial instrument manufacturers on the market, and the metal ring sizes of triaxial instruments produced by different manufacturers vary significantly. Furthermore, these manufacturers typically do not pay attention to the initial sample preparation process.

[0003] The lack of a universal sample preparation mold compatible with different instruments makes sample preparation cumbersome and time-consuming, and prone to problems such as inconsistent density and sample loss, thus affecting the accuracy and efficiency of triaxial compression testing. Furthermore, existing preparation methods cannot guarantee precise control and consistency of sample density, leading to unstable test results and impacting the accuracy and reliability of the tests. Summary of the Invention

[0004] To simplify the operation process, improve the efficiency and safety of sample removal, and enable more efficient and accurate sample preparation, thereby improving the quality and efficiency of triaxial compression testing, this application provides a mold and method for preparing samples of specific densities for triaxial compression testing.

[0005] This application provides a set of molds for preparing samples of specific densities for triaxial compression testing, using the following technical solution:

[0006] A mold for preparing a sample of a specific density for triaxial compression testing includes a clamping assembly, a forming assembly inside the clamping assembly, a pressure applying assembly slidably connected to the clamping assembly, the bottom end of the pressure applying assembly extending into the interior of the forming assembly to apply pressure to the sample located inside the forming assembly, and a functional ring provided at the end of the clamping assembly, the functional ring abutting against the end of the clamping assembly.

[0007] Optionally, the clamping assembly includes an upper flange and a lower flange disposed opposite to each other, the upper flange and the lower flange being slidably connected, the upper flange and the lower flange being coaxially disposed, and the forming assembly passing through the center of the upper flange and being slidably connected relative to each other.

[0008] Optionally, the upper flange includes an upper pressure plate, and an upper guide rod is vertically arranged below the upper pressure plate. The upper guide rod is fixedly connected to the upper pressure plate. The lower flange has a lower through hole relative to the position of the upper guide rod, and the upper guide rod extends into the interior of the lower through hole and is slidably connected to it.

[0009] Optionally, the lower flange includes a lower clamping plate, and a lower guide rod is vertically arranged above the lower clamping plate. The lower guide rod is fixedly connected to the lower clamping plate. The upper flange has an upper through hole at a position relative to the lower guide rod, and the lower guide rod extends into the upper through hole and is slidably connected to it.

[0010] Optionally, multiple upper guide rods are equidistantly arranged along the circumference of the upper pressure plate, and multiple lower through holes on the lower flange are sequentially arranged opposite to the upper guide rods.

[0011] Optionally, a guide cylinder is fixedly connected to the bottom wall of the upper pressing plate. The guide cylinder is coaxially arranged with the upper pressing plate. The forming component is located at the bottom end of the guide cylinder and is arranged opposite to the guide cylinder. The pressure applying component extends into the interior of the guide cylinder and is slidably connected to it.

[0012] Optionally, multiple lower guide rods are equidistantly arranged along the circumference of the lower clamping plate, and multiple upper through holes on the upper flange are sequentially arranged opposite to the lower guide rods.

[0013] Optionally, a plurality of the upper guide rods form a first circumference, and a plurality of the lower guide rods form a second circumference. The diameter of the first circumference is different from the diameter of the second circumference, and the diameter of the functional ring is the same as that of the second circumference. The functional ring is offset from the first circumference.

[0014] Optionally, when the functional ring is located below the lower pressure plate, the functional ring is offset from the upper guide rod, and the top wall of the functional ring abuts against the bottom wall of the lower pressure plate. When the functional ring is located above the upper pressure plate, the functional ring is opposite to the lower guide rod, and the bottom wall of the functional ring abuts against the top wall of the upper guide rod.

[0015] Optionally, the inner wall diameter of the functional ring is the same as the diameter of the first circumference. When the functional ring is located below the lower pressing plate, the inner wall of the functional ring abuts against the side walls of the plurality of upper guide rods.

[0016] Optionally, the sidewall of the guide cylinder abuts against the sidewall of the molding assembly, and the interior of the guide cylinder is in communication with the interior of the molding assembly.

[0017] Optionally, the molding assembly includes a sample ring, which is an annular structure, and the interior of the sample ring is in communication with the interior of the guide cylinder.

[0018] Optionally, the inner wall diameter of the sample ring, the inner wall diameter of the guide cylinder, and the outer wall diameter of the molding component extending into the guide cylinder are all the same.

[0019] Optionally, when the bottom wall of the guide cylinder abuts against the top wall of the sample ring, the top end of the lower guide rod protrudes from the inside of the upper through hole, and the top wall of the lower guide rod is higher than the top wall of the upper clamping plate.

[0020] Optionally, when the bottom wall of the guide cylinder abuts against the top wall of the sample ring, the bottom end of the upper guide rod protrudes from the inside of the lower through hole, and the bottom wall of the upper guide rod is lower than the bottom wall of the lower clamping plate.

[0021] Optionally, the pressure application assembly includes a piston that is slidably connected to the clamping assembly, and the piston can extend into the interior of the molding assembly and is slidably connected to it.

[0022] Optionally, the outer wall of the piston slides against the inner wall of the molding assembly.

[0023] Optionally, the piston includes a forming part, and a limiting part is fixedly connected to the top end of the forming part. The diameter of the limiting part is larger than the diameter of the forming part. When the forming part is completely inside the clamping assembly, the limiting part is located outside the clamping assembly.

[0024] Optionally, the diameter of the outer side wall of the limiting part is not greater than the diameter of the inner side wall of the functional ring.

[0025] A method for preparing a test sample of a specific density for a triaxial compression test, applied to a mold for preparing test samples of a specific density for a triaxial compression test, the method comprising:

[0026] S01: Assembly mold: Place the sample ring above the lower flange, so that the bottom wall of the sample ring abuts against the top wall of the lower flange;

[0027] S02: Filling the sample: Fill the sample ring with the sample to be tested to ensure uniform filling of the sample and reduce air saturation and non-uniform density.

[0028] S03: Compressing the sample: Place the piston and the upper flange on the sample ring, extend the upper guide rod into the lower through hole, extend the lower guide rod into the upper through hole, extend the piston into the guide cylinder, the drive piston of the single-axis compressor is located on the piston, start the single-axis compressor, the drive piston of the single-axis compressor drives the piston to move, the piston compresses the sample downward until the sample density reaches the preset density;

[0029] S04: Turn off the single-axis compressor, place the functional ring above the upper flange, align the functional ring with the multiple lower guide rods, restart the single-axis compressor, detach the upper flange from the lower flange, turn off the single-axis compressor, and remove the compacted sample from the sample ring.

[0030] In summary, this application includes at least one of the following beneficial technical effects:

[0031] This application, through its simple design, successfully overcomes the shortcomings of existing technologies. After the sample is compressed, the entire system can be easily opened simply by placing the functional ring on top, without requiring additional force to knock or smash the mold. This design greatly simplifies the operation process, improves the efficiency and safety of sample removal, reduces the risk of mold damage due to improper operation, and extends the mold's service life. This application not only reduces the difficulty of manufacturing and maintenance but also lowers manufacturing costs, enabling its widespread application in areas lacking advanced manufacturing equipment and technology, and significantly improving the efficiency and quality of triaxial compression testing. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of a mold for preparing a sample of a specific density for triaxial compression testing in an embodiment of this application, under pressure.

[0033] Figure 2 This is a schematic diagram of the structure of a mold for preparing a sample of a specific density for triaxial compression testing in an embodiment of this application, in the form of a disassembly.

[0034] Figure 3 This is an exploded view of a mold used in an embodiment of this application to prepare a sample of a specific density for a triaxial compression test.

[0035] Figure 4 This is a schematic diagram of the upper clamping plate of a mold for preparing a sample of a specific density for triaxial compression testing, as described in an embodiment of this application.

[0036] Figure 5 This is a schematic diagram of the lower clamping plate of a mold for preparing a sample of a specific density for triaxial compression testing, as described in an embodiment of this application.

[0037] Explanation of reference numerals in the attached drawings: 1. Clamping assembly; 11. Upper flange; 111. Upper clamping plate; 112. Upper guide rod; 113. Upper through hole; 114. Guide cylinder; 12. Lower flange; 121. Lower clamping plate; 122. Lower guide rod; 123. Lower through hole; 2. Forming assembly; 21. Sample ring; 3. Pressurizing assembly; 31. Piston; 311. Forming part; 312. Limiting part; 4. Functional ring. Detailed Implementation

[0038] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0040] Triaxial compression testing is a standard method for investigating the mechanical properties of soil and rock materials, and its results are of crucial value for the design and analysis of geological engineering projects. To ensure the accuracy and reliability of the test results, samples of a specific density must be prepared to simulate actual geological conditions. In traditional preparation processes, soil is typically compressed to a predetermined density using a uniaxial compressor, and then the compacted sample is placed in a triaxial instrument for testing. However, there are numerous triaxial instrument manufacturers on the market, and the metal ring sizes of triaxial instruments produced by different manufacturers vary significantly. Furthermore, these manufacturers typically do not pay attention to the initial sample preparation process.

[0041] The lack of a universal sample preparation mold compatible with different instruments makes sample preparation cumbersome and time-consuming, and prone to problems such as inconsistent density and sample loss, thus affecting the accuracy and efficiency of triaxial compression testing. Furthermore, existing preparation methods cannot guarantee precise control and consistency of sample density, leading to unstable test results and impacting the accuracy and reliability of the tests.

[0042] To simplify the operation process, improve the efficiency and safety of sample removal, and enable more efficient and accurate sample preparation, thereby improving the quality and efficiency of triaxial compression testing, this application provides a mold and method for preparing samples of specific densities for triaxial compression testing.

[0043] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0044] This application discloses a mold for preparing samples of specific densities for triaxial compression testing. (Refer to...) Figure 1 , Figure 2 A mold for preparing a sample of a specific density for triaxial compression testing includes a clamping assembly 1. Inside the clamping assembly 1 is a forming assembly 2, which is used to limit and shape the sample. The clamping assembly 1 clamps and fixes the forming assembly 2. A pressure-applying assembly 3 is also located on the clamping assembly 1. The pressure-applying assembly 3 extends into the clamping assembly 1 and is slidably connected to it. The bottom end of the pressure-applying assembly 3 is opposite to the forming assembly 2, thereby applying pressure to shape the sample inside the forming assembly 2. A functional ring 4 is located at the outer end of the clamping assembly 1. When the functional ring 4 is below the clamping assembly 1, it provides support, reducing the height of the clamping assembly 1 and thus stabilizing the forming assembly 2. When the functional ring 4 is above the clamping assembly 1, it provides downward pressure, increasing the height of the clamping assembly 1, allowing disassembly of the entire device.

[0045] Reference Figure 3 , Figure 4 The clamping assembly 1 includes an upper flange 11 and a lower flange 12 arranged opposite to each other. The upper flange 11 includes a horizontally arranged upper clamping plate 111, which has a disc-shaped structure and its axis is vertically arranged. An upper guide rod 112 is vertically arranged below the upper clamping plate 111 and is fixedly connected to it. Multiple upper guide rods 112 are equidistantly arranged along the axis of the upper clamping plate 111. In one embodiment, three upper guide rods 112 are equidistantly arranged along the circumference of the upper clamping plate 111, and the arc connecting the three upper guide rods 112 forms a first circumference, the axis of which coincides with the axis of the upper clamping plate 111.

[0046] Reference Figure 3 , Figure 5 The lower flange 12 includes a horizontally arranged lower clamping plate 121. The lower clamping plate 121 has a disc-shaped structure, and its axis is vertically arranged. The lower clamping plate 121 is coaxially arranged with the upper clamping plate 111. A lower guide rod 122 is vertically arranged above the lower clamping plate 121 and is fixedly connected to the lower clamping plate 121. Multiple lower guide rods 122 are equidistantly arranged along the circumference of the lower clamping plate 121. In one embodiment, three lower guide rods 122 are equidistantly arranged along the circumference of the lower clamping plate 121, and the arc connecting the three lower guide rods 122 forms a second circumference. The axis of the second circumference coincides with the axis of the lower clamping plate 121.

[0047] An upper through hole 113 is provided on the surface of the upper pressure plate 111 relative to the lower guide rod 122, and the upper through hole 113 completely penetrates the surface of the upper pressure plate 111. When the upper pressure plate 111 and the lower pressure plate 121 are opposite to each other, the lower guide rod 122 is positioned opposite to the upper through hole 113, and the lower guide rod 122 extends into the interior of the upper through hole 113. The lower guide rod 122 is slidably connected to the upper pressure plate 111, so that the lower guide rod 122 can slide relative to the upper through hole 113 within the upper through hole 113 along the guide of the upper through hole 113.

[0048] A lower through hole 123 is provided on the surface of the lower pressing plate 121 relative to the upper guide rod 112, completely penetrating the surface of the lower pressing plate 121. When the upper pressing plate 111 and the lower pressing plate 121 are opposite each other, the upper guide rod 112 and the lower through hole 123 are positioned opposite each other, with the upper guide rod 112 extending into the lower through hole 123. The upper guide rod 112 and the lower pressing plate 121 are slidably connected, allowing the upper guide rod 112 to slide relative to each other within the lower through hole 123 along the guide of the lower through hole 123. Thus, by sliding the upper guide rod 112 relative to each other within the lower through hole 123 and the lower guide rod 122 relative to each other within the upper through hole 113, the distance between the opposing upper pressing plate 111 and lower pressing plate 121 can be adjusted.

[0049] The diameter of the first circumference formed by the three upper guide rods 112 is different from the diameter of the second circumference formed by the three lower guide rods 122. In one embodiment, the diameter of the first circumference formed by the three upper guide rods 112 is smaller than the diameter of the second circumference formed by the three lower guide rods 122.

[0050] A guide cylinder 114 is vertically arranged below the upper pressure plate. The guide cylinder 114 is a hollow cylindrical structure and is coaxially arranged with the upper pressure plate 111. The guide cylinder 114 and the upper pressure plate 111 are fixedly connected. The central through hole of the guide cylinder 114 is opposite to the central through hole of the upper pressure plate 111, so that the pressure application component 3 can extend into the central through hole of the guide cylinder 114 from the central through hole of the upper pressure plate 111.

[0051] The molding assembly 2 includes a sample ring 21 disposed between the lower surface of the guide cylinder 114 of the upper flange 11 and the upper surface of the lower clamping plate 121 of the lower flange 12. The sample ring 21 has a circular structure and is coaxially arranged with the upper flange 11. The upper surface of the sample ring 21 abuts against the lower surface of the guide cylinder 114, and the central opening of the sample ring 21 is opposite to the central opening of the guide cylinder 114. The diameter of the central opening of the sample ring 21 is the same as the diameter of the central opening of the guide cylinder 114, and the internal space of the sample ring 21 is in communication with the internal space of the guide cylinder 114. The lower surface of the sample ring 21 abuts against the upper surface of the lower clamping ring, thereby clamping and fixing the sample ring 21 by the guide cylinder 114 of the upper flange 11 and the lower clamping plate 121 of the lower flange 12.

[0052] After the upper flange 11, guide cylinder 114, sample ring 21 and lower flange 12 are installed in sequence, the lower surface of the guide cylinder 114 abuts against the upper surface of the sample ring 21, and the upper surface of the lower clamping plate 121 of the lower flange 12 abuts against the lower surface of the sample ring 21. At this time, the upper guide rod 112 is located inside the lower through hole 123, the lower guide rod 122 is located inside the upper through hole 113, and the bottom end of the upper guide rod 112 extends out from the inside of the lower through hole 123. The bottom wall of the upper guide rod 112 is lower than the bottom wall of the lower clamping plate 121, and the top end of the lower guide rod 122 extends out from the inside of the upper through hole 113. The top wall of the lower guide rod 122 is higher than the top wall of the upper clamping plate 111.

[0053] Reference Figure 1 , Figure 3 The functional ring 4 has a ring structure, and its diameter is the same as the diameter of the second circumference formed by the three lower guide rods 122. Therefore, when the functional ring 4 is above the upper pressure plate 111 and coaxially arranged with it, it is positioned above the second circumference formed by the three lower guide rods 122. The diameter of the functional ring 4 is larger than the diameter of the first circumference formed by the upper guide rods 112. Therefore, when the functional ring 4 is below the lower pressure plate 121, the ends of the three upper guide rods 112 are all located inside the functional ring 4, and the ends of the upper guide rods 112 are offset from the sidewalls of the functional ring 4.

[0054] The ends of the three upper guide rods 112 are respectively in contact with and slide against the inner sidewall of the functional ring 4, thereby limiting the position of the functional ring 4 below the lower pressure plate 121 through the ends of the three upper guide rods 112, so that the functional ring 4 and the lower pressure plate 121 are coaxially arranged, and when the pressure application component 3 applies downward pressure, the functional ring 4 can provide uniform and stable support to the lower pressure plate 121.

[0055] The pressure application assembly 3 includes a piston 31, which extends into the interior of the guide cylinder 114 through the central through hole of the upper flange 11, and is slidably connected to the upper flange 11 and the guide cylinder 114. The piston 31 includes a vertically arranged forming part 311, and a limiting part 312 is coaxially arranged above the forming part 311. The forming part 311 and the limiting part 312 are fixedly connected, and the diameter of the limiting part 312 is larger than the diameter of the forming part 311. The diameter of the outer wall of the forming part 311 is the same as the diameter of the inner wall of the guide cylinder 114. The inner wall diameter of the sample ring 21, the inner wall diameter of the guide cylinder 114, and the outer wall diameter of the forming part 311 of the piston 31 are the same. The diameter of the limiting part 312 of the piston 31 is not larger than the inner wall diameter of the functional ring 4, so that when the functional ring 4 is located above the upper pressure plate 111, the functional ring 4 and the piston 31 can be staggered.

[0056] When the piston 31 extends into the guide cylinder 114 through the central through hole of the upper flange 11, the outer wall of the forming part 311 of the piston 31 abuts against and slides relative to the inner wall of the guide cylinder 114. As the piston 31 gradually descends, the bottom end of the piston 31 contacts the top of the sample inside the sample ring 21. Then, as the piston 31 descends further, it compacts the sample inside the sample ring 21.

[0057] When the entire system is in the clamping operation, the functional ring 4 is placed below the lower clamping plate 121 and limited by the three upper guide rods 112, so that the functional ring 4 and the lower clamping plate 121 are coaxially arranged, and the upper surface of the functional ring 4 abuts against the lower surface of the lower clamping plate 121. By pressing down the piston 31, the forming part 311 of the piston 31 compacts the sample located inside the sample ring 21.

[0058] When the entire system is disassembled, the functional ring 4 is placed above the upper pressure plate 11, and the functional ring 4 is located at the top of the lower guide rod 122. The external single-shaft compressor drives the functional ring 4 to move downward, and the functional ring 4 pushes the lower guide rod 122 to move downward. The lower guide rod 122 disengages from the internal components of the upper through hole 113, and the upper guide rod 112 disengages from the internal components of the lower through hole 123. As a result, the end of the upper guide rod 112 is completely located inside the lower flange 12, thereby separating the upper flange 11 from the lower flange 12.

[0059] This application also provides a method for preparing a test sample of a specific density for a triaxial compression test, applied to the aforementioned set of molds for preparing test samples of a specific density for a triaxial compression test, the method comprising:

[0060] S01: Assembly mold: Place the sample ring 21 above the lower flange 12 so that the bottom wall of the sample ring 21 abuts against the top wall of the lower flange 12.

[0061] S02: Filling the sample: Fill the sample ring 21 with the sample to be tested to ensure uniform filling of the sample and reduce air saturation and non-uniform density.

[0062] S03: Compressing the sample: Place the piston 31 and the upper flange 11 on the sample ring 21. The upper guide rod 112 extends into the lower through hole 123, and the lower guide rod 122 extends into the upper through hole 113. Insert the piston 31 into the guide cylinder 114. The drive piston 31 of the single-axis compressor is located on the piston 31. Start the single-axis compressor. The drive piston 31 of the single-axis compressor drives the piston 31 to move. The piston 31 compresses the sample downward until the sample density reaches the preset density.

[0063] S04: Turn off the single-shaft compressor, place the functional ring 4 above the upper flange 11, align the functional ring 4 with the multiple lower guide rods 122, restart the single-shaft compressor, separate the upper flange 11 from the lower flange 12, turn off the single-shaft compressor, and remove the compacted sample from the sample ring 21.

[0064] The implementation principle of a mold for preparing a sample of a specific density for triaxial compression testing according to an embodiment of this application is as follows: A sample ring 21 is placed on a lower flange 12, with the bottom wall of the sample ring 21 abutting against the lower flange 12. The sample to be tested is placed inside the sample ring 21. An upper flange 11 is placed above the sample ring 21, with the bottom wall of the guide cylinder 114 of the upper flange 11 abutting against the top wall of the sample ring 21. A piston 31 extends from the central hole of the upper flange 11 and into the guide cylinder 114. A single-axis compressor presses down on the piston 31, compressing the sample downwards until the sample reaches a predetermined density. After compaction, a functional ring 4 is placed above the upper flange 11, with the bottom wall of the functional ring 4 abutting against the top wall of the lower guide rod 122. The single-axis compressor presses down on the functional ring 4, causing the upper flange 11 to detach from the lower flange 12. In this invention, the term "multiple" refers to at least two or more, unless otherwise explicitly defined. The terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0065] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A mold for preparing a sample of a specific density for a triaxial compression test, characterized in that: The device includes a clamping assembly (1), a forming assembly (2) is provided inside the clamping assembly (1), a pressure applying assembly (3) is slidably connected to the clamping assembly (1), the bottom end of the pressure applying assembly (3) extends into the interior of the forming assembly (2) to apply pressure to the sample located inside the forming assembly (2), and a functional ring (4) is provided at the end of the clamping assembly (1), the functional ring (4) abuts against the end of the clamping assembly (1); The clamping assembly (1) includes an upper flange (11) and a lower flange (12) disposed opposite to each other. The upper flange (11) and the lower flange (12) are slidably connected and are coaxially disposed. The upper flange (11) includes an upper pressure plate (111), and an upper guide rod (112) is vertically arranged below the upper pressure plate (111). The upper guide rod (112) is fixedly connected to the upper pressure plate (111). The lower flange (12) has a lower through hole (123) at a position relative to the upper guide rod (112). The upper guide rod (112) extends into the lower through hole (123) and is slidably connected to it. The bottom wall of the upper pressing plate (111) is fixedly connected to a guide cylinder (114). The lower flange (12) includes a lower clamping plate (121), and a lower guide rod (122) is vertically arranged above the lower clamping plate (121). The lower guide rod (122) is fixedly connected to the lower clamping plate (121). The upper flange (11) has an upper through hole (113) at a position relative to the lower guide rod (122). The lower guide rod (122) extends into the upper through hole (113) and is slidably connected to it. Multiple upper guide rods (112) form a first circumference, and multiple lower guide rods (122) form a second circumference. The diameter of the first circumference is different from the diameter of the second circumference. The diameter of the functional ring (4) is the same as that of the second circumference. The functional ring (4) is offset from the first circumference. When the functional ring (4) is located below the lower pressing plate (121), the functional ring (4) is offset from the upper guide rod (112), and the top wall of the functional ring (4) abuts against the bottom wall of the lower pressing plate (121). When the functional ring (4) is located above the upper pressing plate (111), the functional ring (4) is opposite to the lower guide rod (122), and the bottom wall of the functional ring (4) abuts against the top wall of the upper guide rod (112). The inner side wall diameter of the functional ring (4) is the same as the diameter of the first circumference. When the functional ring (4) is located below the lower pressing plate (121), the inner side wall of the functional ring (4) abuts against the side walls of the multiple upper guide rods (112). The pressure application assembly (3) includes a piston (31); The molding component (2) includes a sample ring (21).

2. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 1, characterized in that: The molding component (2) passes through the center of the upper flange (11) and is slidably connected to it.

3. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 2, characterized in that: Multiple upper guide rods (112) are equidistantly arranged along the circumference of the upper pressure plate (111), and multiple lower through holes (123) on the lower flange (12) are arranged opposite to the upper guide rods (112) in sequence.

4. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 3, characterized in that: The guide cylinder (114) is coaxially arranged with the upper pressure plate (111), the forming component (2) is located at the bottom end of the guide cylinder (114), and the forming component (2) is arranged opposite to the guide cylinder (114). The pressure application component (3) extends into the interior of the guide cylinder (114) and is slidably connected to it.

5. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 1, characterized in that: Multiple lower guide rods (122) are equidistantly arranged along the circumference of the lower clamping plate (121), and multiple upper through holes (113) on the upper flange (11) are arranged opposite to the lower guide rods (122) in sequence.

6. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 4, characterized in that: The side wall of the guide cylinder (114) abuts against the side wall of the molding component (2), and the interior of the guide cylinder (114) is in relative communication with the interior of the molding component (2).

7. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 6, characterized in that: The sample ring (21) has an annular structure, and the interior of the sample ring (21) is in relative communication with the interior of the guide cylinder (114).

8. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 7, characterized in that: The inner wall diameter of the sample ring (21), the inner wall diameter of the guide cylinder (114), and the outer wall diameter of the molding component (2) extending into the guide cylinder (114) are all the same.

9. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 8, characterized in that: When the bottom wall of the guide cylinder (114) abuts against the top wall of the sample ring (21), the top end of the lower guide rod (122) passes through the interior of the upper through hole (113), and the top wall of the lower guide rod (122) is higher than the top wall of the upper pressure plate (111).

10. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 9, characterized in that: When the bottom wall of the guide cylinder (114) abuts against the top wall of the sample ring (21), the bottom end of the upper guide rod (112) passes through the interior of the lower through hole (123), and the bottom wall of the upper guide rod (112) is lower than the bottom wall of the lower clamping plate (121).

11. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 1, characterized in that: The piston (31) is slidably connected to the clamping assembly (1), and the piston (31) can extend into the interior of the molding assembly (2) and be slidably connected to it.

12. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 11, characterized in that: The outer wall of the piston (31) slides against the inner wall of the molding assembly (2).

13. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 11, characterized in that: The piston (31) includes a forming part (311), and a limiting part (312) is fixedly connected to the top end of the forming part (311). The diameter of the limiting part (312) is larger than the diameter of the forming part (311). When the forming part (311) is completely inside the clamping assembly (1), the limiting part (312) is located outside the clamping assembly (1).

14. The mold for preparing a sample of a specific density for triaxial compression testing according to claim 13, characterized in that: The outer wall diameter of the limiting part (312) is not greater than the inner wall diameter of the functional ring (4).

15. A method for preparing a sample of a specific density for a triaxial compression test, characterized in that, The method, which utilizes a set of molds for preparing triaxial compression test samples of a specific density as described in any one of claims 1-14, comprises: S01: Assembly mold: Place the sample ring (21) above the lower flange (12) so that the bottom wall of the sample ring (21) abuts against the top wall of the lower flange (12); S02: Filling the sample: Fill the sample to be tested into the sample ring (21) to ensure uniform filling of the sample and reduce air saturation and non-uniform density; S03: Compressing the sample: Place the piston (31) and the upper flange (11) on the sample ring (21), extend the upper guide rod (112) into the lower through hole (123), extend the lower guide rod (122) into the upper through hole (113), extend the piston (31) into the guide cylinder (114), the drive piston of the single-axis compressor is located on the piston (31), start the single-axis compressor, the drive piston of the single-axis compressor drives the piston (31) to move, the piston (31) compresses the sample downward until the density of the sample reaches the preset density; S04: Turn off the single-axis compressor, place the functional ring (4) above the upper flange (11), align the functional ring (4) with the multiple lower guide rods (122), restart the single-axis compressor, separate the upper flange (11) from the lower flange (12), turn off the single-axis compressor, and take out the compacted sample from the sample ring (21).

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