Universal sample preparation and high-frequency vibration loading integrated device and method for triaxial test

Abstract

The invention relates to a triaxial test universal sample preparation and high-frequency vibration loading integrated device and method, the device comprises a main body loading frame, a sample preparation suite, a loading suite and a loader, and the loader comprises a voice coil motor; the main body loading frame comprises a supporting plate, a supporting rod and a loading ejector rod, a working space is formed between the supporting plate and the supporting rod, one end of the loading ejector rod is connected with the loader, and the other end of the loading ejector rod extends into the working space; a soil sample is placed in the sample preparation suite, and the loading ejector rod loads static force or surface vibration to the sample preparation suite; a sample prepared in the sample preparation suite is placed in the loading suite, and the loading ejector rod loads static force or power to the loading suite. Compared with the prior art, the sample preparation and loading of the triaxial test sample are realized through the sample preparation suite and the loading suite, and the operation is convenient; and the loader adopts electric loading, so that the problems of compactness, stable quality and the like during sample manufacturing can be solved, and the test error can be effectively reduced while manpower is saved.

Description

Technical Field

[0001] The invention relates to geotechnical engineering triaxial test equipment, and in particular to a triaxial test universal sample preparation and high-frequency vibration loading integrated device and method. Background Art

[0002] With the continuous growth of transportation demand and the rapid development of transportation infrastructure construction, the roadbed filling materials of high-speed railways and highways are generally coarse-grained soil. Under the action of high-speed, heavy-loaded and large-volume traffic cycle loads, the roadbed filling materials often experience particle sliding, dislocation and even crushing, which manifests as roadbed settlement on a macro scale. Therefore, in order to study the static and dynamic mechanical properties of coarse-grained soil as a filler, a series of experimental studies are needed to reveal its deformation mechanism and improve the long-term service performance of roadbed filling materials.

[0003] As the most direct and effective indoor unit test, the triaxial test requires the maximum dry density to be determined in advance before preparing the sample, and then triaxial samples of different dry densities are prepared according to the corresponding design requirements. The existing sample preparation methods are roughly divided into static compaction method and surface vibration method. The existing methods are all manually operated, and the compaction height control is not precise enough, which has a great impact on the compaction quality of the sample; secondly, the existing triaxial test sample preparation and loading are carried out separately using different devices, and the preparation and loading process is relatively cumbersome.

[0004] After searching, the application publication number CN116625789A discloses a coarse-grained soil triaxial sample compaction and demoulding device and its use method, which specifically discloses: including a base, a spinning support mechanism, a spinning compaction mechanism, a cylinder release mechanism and a sample preparation cylinder; the spinning support mechanism is fixedly connected to the base and arranged on the outside of the base; the spinning compaction mechanism is movably installed on the spinning support mechanism and is located directly above the base; the cylinder release mechanism is arranged at the top of the base, and a sample preparation cylinder is arranged on the cylinder release mechanism; the sample preparation cylinder is composed of four single arc-shaped pieces, the four arc-shaped pieces are concentrically arranged, and each arc-shaped piece is connected to different positions of the cylinder release mechanism. However, this prior art can only realize the preparation of triaxial test specimens.

[0005] In summary, how to design a device capable of preparing and loading triaxial test specimens is a technical problem that needs to be solved. Summary of the invention

[0006] The purpose of the present invention is to provide a universal triaxial test sample preparation and high-frequency vibration loading integrated device and method in order to overcome the defects of the above-mentioned prior art that the preparation and loading of triaxial test specimens are carried out separately by different devices, and the preparation and loading process is relatively cumbersome.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] According to one aspect of the present invention, a triaxial test universal sample preparation and high-frequency vibration loading integrated device is provided, in which a soil sample is prepared as a sample and subjected to a loading test, comprising a main loading frame and a sample preparation kit, a loading kit and a loader installed on the main loading frame, wherein the loader comprises a voice coil motor, which provides power at a frequency of 30 to 100 Hz; the main loading frame comprises a support plate, a support rod and a loading push rod, wherein the support rod is installed on both sides of the support plate, a working space is formed between the support plate and the support rod, one end of the loading push rod is connected to the loader, and the other end extends into the working space; the sample preparation kit or the loading kit is installed in the working space; when the sample preparation kit is located in the working space, a soil sample is placed in the sample preparation kit, and the loading push rod loads static force or surface vibration to the sample preparation kit; when the loading kit is located in the working space, the sample prepared in the sample preparation kit is placed in the loading kit, and the loading push rod loads static force or dynamic force to the loading kit.

[0009] As a preferred technical solution, the support plate includes a bottom plate and a top plate installed in parallel in sequence, and the support rod passes through the edges of the bottom plate and the top plate; one end of the loader is installed on the top plate, and the other end passes through the top plate and is connected to the loading top rod.

[0010] As a preferred technical solution, the support plate also includes a loading adjustment plate which is parallel and installed between the bottom plate and the top plate, and the loading adjustment plate forms a moving pair with the support rod; one end of the loader passes through the loading adjustment plate and is connected to the loading adjustment plate; a working space is formed between the support rod, the bottom plate and the loading adjustment plate.

[0011] As a preferred technical solution, a limiting slot is provided on the bottom plate, and a limiting protrusion is provided at one end of the sample preparation kit and the loading kit, and the limiting slot and the limiting protrusion cooperate with each other.

[0012] As a preferred technical solution, the sample preparation kit includes a sample pressing head, a plurality of layered limiting rings, a sample forming tube and a sample preparing base. The sample preparing base is installed on a support plate close to the ground. When the sample preparation kit is in the first working state, one end of the sample forming tube is installed in the sample preparing base, and the other end is stacked with a layered limiting ring. The soil sample is placed in the sample forming tube, and the sample pressing head is placed in the sample forming tube. The sample pressing head and the sample forming tube are clearance-matched; the loading push rod loads static force or surface vibration to the sample pressing head.

[0013] As a preferred technical solution, the sample forming tube includes an integral sample forming tube and a three-petal sample forming tube. The loading push rod loads static force to the sample pressing head installed on the integral sample forming tube, and the loading push rod loads surface vibration to the sample pressing head installed on the three-petal sample forming tube.

[0014] As a preferred technical solution, a cylindrical rubber mold is placed in the three-petal sample tube, and the outer diameter of the rubber mold is equal to the inner diameter of the three-petal sample tube.

[0015] As a preferred technical solution, the sample preparation kit also includes a demolding cylinder. When the sample preparation kit is in the second working state, one end of the sample pressing head is installed in the sample preparation base, the layered limiting ring and the sample cylinder are stacked on the sample pressing head in sequence, the sample is located in the sample cylinder, and the demolding cylinder is placed on the sample cylinder. The inner diameter of the demolding cylinder is larger than the inner diameter of the sample cylinder and smaller than the outer diameter of the sample cylinder.

[0016] As a preferred technical solution, the loading kit includes a triaxial pressure chamber, a pressure chamber base, an extension rod, a bearing bottom plate and a bearing top plate. The surface of the triaxial pressure chamber is provided with a pipe joint, and the pipe joint is connected to a water source or an air source; the pressure chamber base is installed on a support plate close to the ground, and the triaxial pressure chamber is installed on the pressure chamber base; one end of the extension rod is connected to the loading top rod, and the other end passes through the triaxial pressure chamber to connect to the bearing top plate; the bearing bottom plate is installed in the triaxial pressure chamber, the sample is placed on the bearing bottom plate, and the bearing top plate is against the sample to load static or dynamic force on the sample.

[0017] According to another aspect of the present invention, a method using a triaxial test universal sample preparation and high-frequency vibration loading integrated device is provided, which specifically comprises the following steps:

[0018] Step S101, the sample preparation kit is installed in the main loading frame, and the soil sample is added into the sample preparation kit;

[0019] Step S102, the loader applies static force or surface vibration to the sample preparation kit;

[0020] Step S103, after the sample preparation is completed, the sample preparation kit is removed, the loading kit is installed, and the sample is placed in the loading kit;

[0021] Step S104, the loading push rod applies static force or dynamic force to the loading kit.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The present invention realizes the sample preparation and loading of the triaxial test specimen through the sample preparation kit and the loading kit, and the operation is convenient; the loader adopts electric loading, which can meet the power loading with a maximum frequency of 100Hz, making up for the defect of the existing triaxial test device with a low frequency, and can ensure the compaction degree and stable quality during sample preparation, saving manpower and effectively reducing the test error;

[0024] 2) The demoulding of the present invention is carried out through a demoulding cylinder, which is simple and easy to operate, and the demoulding quality is reliable with little disturbance; the convenient installation of the sample preparation kit and the loading kit is realized through the limit card slot; the sample preparation cylinder includes an integral sample preparation cylinder and a three-petal sample preparation cylinder, which is suitable for different treatment methods of different types of soil samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the main loading frame of the present invention and the sample preparation kit in the first working state;

[0026] Figure 2 It is a schematic diagram of the overall structure of the main loading frame of the present invention and the sample preparation kit in the second working state;

[0027] Figure 3 It is a schematic diagram of the overall structure of the main body loading frame, sample pressing head and removed sample of the present invention;

[0028] Figure 4 This is a schematic diagram of the overall structure of the main loading frame and loading kit of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the sample pressing head of the present invention;

[0030] Figure 6 It is a schematic diagram of the overall structure of the integrated sample forming tube of the present invention;

[0031] Figure 7 It is a schematic diagram of the overall structure of the three-petal sample forming tube of the present invention;

[0032] Figure 8 It is a schematic structural diagram of one petal of the three-petal sample tube of the present invention;

[0033] Fig. 9 This is a schematic diagram of the structure of the layered limiting ring of the present invention;

[0034] Fig.10 It is a schematic diagram of the structure of the demoulding cylinder of the present invention;

[0035] Fig.11 This is a schematic diagram of the rubber mold structure of the present invention;

[0036] Fig.12 A flow chart of a method for using a triaxial test specimen according to the present invention;

[0037] The numbers in the figure show:

[0038] 1. Top plate, 2. Loader, 3. Support rod, 4. Loading adjustment plate, 5. Loading ejector rod, 6. Sample pressing head, 7. Layered limiting ring, 8. Bottom plate, 9. Integral sample tube, 10. Sample preparation base, 11. Pressure chamber top plate, 12. Load-bearing top plate, 13. Sample, 14. Extension rod, 15. Load-bearing bottom plate, 16. Pressure chamber, 17. Demolding tube, 18. Three-petal sample tube, 19. Rubber mold. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0040] Example 1

[0041] The present invention provides a triaxial test universal sample preparation and high-frequency vibration loading integrated device, comprising a main loading frame, a sample preparation kit, a loading kit and a loader 2.

[0042] The main loading frame includes a support plate, a support rod 3 and a loading push rod 5. The support plate includes a bottom plate 8, a loading adjustment plate 4 and a top plate 1 which are installed in parallel in sequence. The support rod 3 passes through the edges of the bottom plate 8, the loading adjustment plate 4 and the top plate 1. The support rod 3 is perpendicular to the bottom plate 8, the loading adjustment plate 4 and the top plate 1. A working space is formed between the bottom plate 8, the loading adjustment plate 4 and the support rod 3. The loading push rod 5 is located in the working space and is connected to the loader 2. The loading adjustment plate 4 forms a moving pair with the support rod 3. The loading adjustment plate 4 is connected to the loader 2. The loader 2 drives the loading adjustment plate 4 to move up and down to achieve a rough adjustment of the position of the loading push rod 5. The loading rod drives the loading push rod 5 to move up and down to achieve a fine adjustment of the position of the loading push rod 5.

[0043] like Figures 5 to 11 As shown, the sample preparation kit includes a sample pressing head 6, a layered limiting ring 7, a sample tube, a demoulding tube 17 and a sample preparation base 10. A limiting protrusion is provided on one side of the sample preparation base 10, and a limiting slot is provided on the bottom plate 8. The sample preparation base 10 is installed on the bottom plate 8 through the cooperation of the limiting protrusion and the limiting slot. The sample tube is installed on the sample preparation base 10, the soil sample is placed in the sample tube, and the sample pressing head 6 is placed in the sample tube, and the sample pressing head 6 and the sample tube are clearance-matched. The sample tube includes an integral sample tube 9 and a three-petal sample tube 18. The integral sample tube 9 is a cylindrical structure; the three-petal sample tube 18 includes three arc pieces, and the three arc pieces form a cylindrical structure.

[0044] like Figure 4As shown, the loading kit includes a triaxial pressure chamber 16, a pressure chamber 16 base, an extension rod 14, a bearing bottom plate 15 and a bearing top plate 12. A limiting protrusion is provided on one side of the pressure chamber 16 base, and a limiting slot is provided on the bottom plate 8. The pressure chamber 16 base is installed on the bottom plate 8 through the cooperation of the limiting protrusion and the limiting slot. The triaxial pressure chamber 16 is installed on the pressure chamber 16 base, and a pipe joint is provided on the surface of the triaxial pressure chamber 16, which can be used to connect a water source or an air source. The bearing bottom plate 15 and the bearing top plate 12 are installed in the triaxial pressure chamber 16. One end of the extension rod 14 is connected to the loading top rod 5, and the other end passes through the pressure chamber top plate 11 to connect to the bearing top plate 12. The sample 13 is placed on the bearing bottom plate 15, and the bearing top plate 12 is against the sample 13, and static or dynamic force is loaded on the sample 13. The sample 13 made by surface vibration is generally unable to stand on its own, and needs to be connected to a back-pressure controller to keep the inside of the sample 13 in a vacuum to maintain its upright state. The supporting top plate 12 is connected to the sample 13, and the supporting top plate 12 is connected to a back-pressure controller. The back-pressure controller is located outside the triaxial pressure chamber 16, and a pipeline passes through the pipeline joint of the triaxial pressure chamber 16 to connect to the supporting top plate 12.

[0045] One end of the loader 2 is mounted on the top plate 1, and the other end passes through the top plate 1 and the loading adjustment plate 4 to connect with the loading mandrel 5. A high-precision voice coil motor designed based on the Lorentz force principle is arranged inside the loader 2, which is composed of a permanent magnet, a coil, etc. When the coil is energized, thrust is generated to push the lower loading mandrel 5 to move axially. The motor has high response accuracy and does not have the problem of motion response lag, and can achieve high-frequency power loading with a maximum load of 50kN and a maximum loading frequency of 100Hz.

[0046] Example 2

[0047] like Fig.12 As shown, the present invention provides a sample preparation and loading method using a triaxial test universal sample preparation and high-frequency vibration loading integrated device, which is as follows:

[0048] 1) Install the sample preparation base 10 into the limiting groove of the bottom plate 8 of the main loading frame, and select an integral molding cylinder or a three-petal molding cylinder according to the soil sample type and the sample preparation method to snap into the sample preparation base 10;

[0049] 2) The loading ejector rod 5 applies static force or surface vibration to the sample pressing head 6 to prepare the sample;

[0050] 3) After the sample preparation is completed, the sample preparation kit is removed, the base of the pressure chamber 16 is installed into the limiting groove of the bottom plate 8 of the main loading frame, and the sample 13 is placed in the triaxial pressure chamber 16;

[0051] 4) The loading push rod 5 applies static force or dynamic force to the loading kit.

[0052] The specific process of sample preparation kit is as follows:

[0053] like Figure 1 As shown, when the loading push rod 5 applies static force to the sample pressing head 6, the loading kit is in the first working state, and the integral sample forming tube 9 is used. According to the preset soil dry density, the soil sample required for single-layer compaction is calculated and weighed, and placed in the integral sample forming tube 9, and the sample pressing head 6 is covered, so that the loading push rod 5 is as close to the sample pressing head 6 as possible, and then the sample pressing head 6 is controlled to move downward to the maximum limit depth to compact the soil sample, and then the sample pressing head 6 is lifted to plane the surface of the soil sample, and the layered limit ring 7 is stacked on the sample forming tube, and the soil sample is added again, and the sample pressing head 6 moves downward to compact the soil sample, and the above operation is repeated until the sample 13 is completed. Figure 2 As shown, the loading kit enters the second working state, the sample pressing head 6, the layered limiting ring 7 and the sample tube are inverted on the sample preparation base 10, and the demoulding tube 17 is placed on the sample tube. The inner diameter of the demoulding tube 17 is larger than the inner diameter of the sample tube and smaller than the outer diameter of the sample tube. The loading ejector rod 5 is as close to the loading ejector rod 5 as possible. The loading ejector rod 5 applies static force to the demoulding tube 17, and the demoulding tube 17 moves downward. The sample 13 in the sample tube is squeezed into the demoulding tube 17 by the sample pressing head 6 at the bottom, and the sample 13 is demoulded. Figure 3 shown.

[0054] When the loading push rod 5 loads the sample pressing head 6 with surface vibration, a three-petal sample forming tube 18 is used, and a cylindrical rubber mold 19 is placed in the three-petal sample forming tube 18. The outer diameter of the rubber mold 19 is equal to the inner diameter of the three-petal sample forming tube 18. The soil sample is placed in the rubber mold 19 and covered with the sample pressing head 6, so that the loading push rod 5 is as close to the sample pressing head 6 as possible, and then the sample pressing head 6 is controlled to vibrate and compact to the maximum limit depth, the sample pressing head 6 is taken out, the surface layer of the soil sample is planed, the layered limit ring 7 is stacked on the sample forming tube, and the soil sample is added again. The sample pressing head 6 is vibrated and compacted to the maximum limit depth, and the above operation is repeated until the sample 13 is completed.

[0055] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A triaxial test universal sample preparation and high-frequency vibration loading integrated device, in which a soil sample is prepared into a test specimen (13) and subjected to a loading test, characterized in that: The invention comprises a main body loading frame, a sample preparation kit, a loading kit and a loader (2) installed on the main body loading frame, wherein the loader (2) comprises a voice coil motor and provides power with a frequency of 30 to 100 Hz; the main body loading frame comprises a support plate, a support rod (3) and a loading push rod (5), wherein the support rod (3) is installed on both sides of the support plate, and a working space is formed between the support plate and the support rod (3); one end of the loading push rod (5) is connected to the loader (2), and the other end extends into the working space; the sample preparation kit or the loading kit is installed in the working space; when the sample preparation kit is located in the working space, a soil sample is placed in the sample preparation kit, and the loading push rod (5) loads static force or surface vibration to the sample preparation kit; when the loading kit is located in the working space, a sample (13) prepared in the sample preparation kit is placed in the loading kit, and the loading push rod (5) loads static force or dynamic force to the loading kit.

2. The triaxial test universal sample preparation and high-frequency vibration loading integrated device according to claim 1, characterized in that: The support plate comprises a bottom plate (8) and a top plate (1) which are installed in parallel in sequence, and the support rod (3) passes through the edges of the bottom plate (8) and the top plate (1); one end of the loader (2) is installed on the top plate (1), and the other end passes through the top plate (1) and is connected to the loading top rod (5).

3. The triaxial test universal sample preparation and high-frequency vibration loading integrated device according to claim 2, characterized in that: The support plate further comprises a loading adjustment plate (4) which is parallel to and installed between the bottom plate (8) and the top plate (1); the loading adjustment plate (4) and the support rod (3) form a moving pair; one end of the loader (2) passes through the loading adjustment plate (4) and is connected to the loading adjustment plate (4); a working space is formed between the support rod (3), the bottom plate (8) and the loading adjustment plate (4).

4. The triaxial test universal sample preparation and high-frequency vibration loading integrated device according to claim 2, characterized in that: The bottom plate (8) is provided with a limit slot, and one end of the sample preparation kit and the loading kit is provided with a limit protrusion, and the limit slot and the limit protrusion cooperate with each other.

5. The triaxial test universal sample preparation and high-frequency vibration loading integrated device according to claim 1, characterized in that: The sample preparation kit comprises a sample pressing head (6), a plurality of layered limiting rings (7), a sample forming tube and a sample forming base (10); the sample forming base (10) is mounted on a support plate close to the ground; when the sample preparation kit is in a first working state, one end of the sample forming tube is mounted in the sample forming base (10), and the other end is stacked with a layered limiting ring (7); the soil sample is placed in the sample forming tube, the sample pressing head (6) is placed in the sample forming tube, and the sample pressing head (6) and the sample forming tube are clearance-matched; the loading push rod (5) loads static force or surface vibration to the sample pressing head (6).

6. The triaxial test universal sample preparation and high-frequency vibration loading integrated device according to claim 5, characterized in that: The sample forming tube comprises an integral sample forming tube (9) and a three-petal sample forming tube (18), the loading push rod (5) applies static force to a sample pressing head (6) installed on the integral sample forming tube (9), and the loading push rod (5) applies surface vibration to a sample pressing head (6) installed on the three-petal sample forming tube (18).

7. The triaxial test universal sample preparation and high-frequency vibration loading integrated device according to claim 6, characterized in that: A cylindrical rubber mold (19) is placed inside the three-petal sample tube (18), and the outer diameter of the rubber mold (19) is equal to the inner diameter of the three-petal sample tube (18).

8. The triaxial test universal sample preparation and high-frequency vibration loading integrated device according to claim 5, characterized in that: The sample preparation kit also includes a demoulding cylinder (17). When the sample preparation kit is in the second working state, one end of the sample pressing head (6) is installed in the sample preparation base (10), the layered limiting ring (7) and the sample forming cylinder are stacked on the sample pressing head (6) in sequence, the sample (13) is located in the sample forming cylinder, and the demoulding cylinder (17) is placed on the sample forming cylinder. The inner diameter of the demoulding cylinder (17) is larger than the inner diameter of the sample forming cylinder and smaller than the outer diameter of the sample forming cylinder.

9. The triaxial test universal sample preparation and high-frequency vibration loading integrated device according to claim 1, characterized in that: The loading kit comprises a triaxial pressure chamber (16), a pressure chamber (16) base, an extension rod (14), a bearing bottom plate (15) and a bearing top plate (12); a pipe joint is provided on the surface of the triaxial pressure chamber (16), and the pipe joint is connected to a water source or an air source; the pressure chamber (16) base is installed on a support plate close to the ground, and the triaxial pressure chamber (16) is installed on the pressure chamber (16) base; one end of the extension rod (14) is connected to the loading top rod (5), and the other end passes through the triaxial pressure chamber (16) to connect to the bearing top plate (12); the bearing bottom plate (15) is installed in the triaxial pressure chamber (16), the sample (13) is placed on the bearing bottom plate (15), and the bearing top plate (12) is against the sample (13), so as to load static force or dynamic force on the sample (13).

10. A method using the triaxial test universal sample preparation and high-frequency vibration loading integrated device according to any one of claims 1 to 9, characterized in that: The specific steps include: Step S101, the sample preparation kit is installed in the main loading frame, and the soil sample is added into the sample preparation kit; Step S102, the loader (2) applies static force or surface vibration to the sample preparation kit; Step S103, after the sample preparation is completed, the sample preparation kit is removed, the loading kit is installed, and the sample (13) is placed in the loading kit; Step S104, the loading mandrel (5) applies static force or dynamic force to the loading kit.

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