Geotechnical test cohesive soil homogenization sample preparation device and method

Abstract

The invention discloses a soil test cohesive soil homogenization sample preparation device and method, and relates to the field of soil tests, the soil test cohesive soil homogenization sample preparation device comprises a bearing base arranged at the bottom of the sample preparation device and used for bearing the sample preparation device; the sample preparation device is installed on the upper surface of the bearing base and connected with the support rod through a hydraulic oil cylinder, a cylinder body is arranged in the sample preparation device, and a soil sample for the geotechnical test is poured into the cylinder body through a natural shakeout method; the top end of the hydraulic oil cylinder is fixed on the bracket rod, the bottom end of the hydraulic oil cylinder is fixed on the sample preparation device, and the hydraulic oil cylinder drives the sample preparation device to move along the geometric center direction of the bearing base to realize opening and closing of the sample preparation device; the top plate is mounted on the upper surface of the sample preparation device and is fixed through the bracket rod; one end of the support rod is fixed on the upper surface of the bearing base. Soil particles are remolded to be in a required cylindrical shape in an annular extrusion mode, the non-uniform defect that the density of the lower portion is large and the density of the upper portion is small under the action of gravity of the particles is overcome, the whole operation process is simple, and carrying, dismounting and mounting are convenient.

Description

Technical Field

[0001] The invention relates to the field of geotechnical testing, and in particular to a device and method for preparing a homogenized sample of clay soil in a geotechnical testing. Background Art

[0002] Clay in nature is a good natural building material. Its application range includes but is not limited to ceramic manufacturing, cement production, mold manufacturing, pigments and pharmaceutical industries. It is easy to obtain and has high economic value. my country is one of the countries with the most extensive distribution of clay. Many provinces have rich clay resources stored on the surface. Strengthening the research on the load-displacement characteristics of clay (also known as stress-strain or constitutive relationship) is very helpful for in-depth understanding of the mechanical properties of clay in various territories. Before the application and promotion of clay in engineering, it is often necessary to carry out unit tests or basic research in order to obtain the strength and deformation characteristics of homogeneous soil and derive the intrinsic constitutive law. Among them, the key link of geotechnical testing is the preparation of samples, which is also the primary prerequisite for conducting experiments.

[0003] However, due to the constraints of existing geotechnical equipment manufacturing technology, the preparation of homogenized soil samples has always been a difficult problem. For coarse-grained soil, most current experimenters use the natural sand falling method to prepare samples. Although this method can ensure uniformity to a certain extent, it is worth noting that natural soil particles are not ideal spheres, and the particle size of particles has a large span on a small scale. Smaller particles tend to accumulate at the bottom of the sample during the natural fall process, while there are more large particles above. The uniformity of the prepared soil sample still cannot meet the test requirements. For fine-grained soil, layered compaction and layered compaction are often used. Although multiple layered compactions are performed, due to the vertical sampling, it is inevitable that the lower part is dense and the upper part is loose after the sample is prepared. Uneven samples are more likely to induce problems such as strain localization, which ultimately makes it difficult for the measured mechanical behavior to represent the response of the soil "unit". Based on this situation, it is urgent to propose an optimized homogenized sample preparation device and method for clay soil in geotechnical tests.

[0004] Therefore, technicians in this field are committed to developing a device and method for homogenizing clay soil samples for geotechnical testing. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is how to prepare cylindrical clay samples that meet the uniformity requirements for indoor geotechnical mechanics tests, in order to ensure the stability and reliability of subsequent soil mechanical property measurements.

[0006] To achieve the above-mentioned purpose, the present invention provides a device for homogenizing and preparing samples of clay soil for geotechnical tests, comprising a bearing base, a sample preparation device, a hydraulic cylinder, a top plate and a support rod, wherein:

[0007] The supporting base is arranged at the bottom of the sample preparation device and is used to support the sample preparation device;

[0008] The sample maker is mounted on the upper surface of the bearing base, the sample maker is connected to the support rod through the hydraulic cylinder, a cylinder body is arranged inside the sample maker, and the soil sample for geotechnical test is poured into the cylinder body of the sample maker by natural sand falling method;

[0009] The hydraulic cylinder, the top end of which is fixed on the support rod, and the bottom end of which is fixed on the sample maker, and the hydraulic cylinder drives the sample maker to move along the geometric center direction of the bearing base to realize the opening and closing of the sample maker;

[0010] The top plate is mounted on the upper surface of the sample preparation device and is fixed by the support rod;

[0011] The support rod, the first end of the support rod is fixedly mounted on the upper surface of the bearing base, and the second end of the support rod is fixedly connected to the top plate.

[0012] Furthermore, the sample maker is installed at the geometric center position of the upper surface of the supporting base, and the sample maker includes a positioning aluminum sheet and an aluminum shell plate. The positioning aluminum sheet is installed in a slot inside the aluminum shell plate, and hooks are provided at both ends of the positioning aluminum sheet; the aluminum shell plate constitutes the cylinder body of the sample maker.

[0013] Furthermore, there are multiple locking aluminum sheets and aluminum shell plates, and the number is the same; when the sample maker is closed, the two ends of the multiple aluminum shell plates are connected in pairs, and the locking aluminum sheets are completely embedded in the aluminum shell plates and cannot leak out; when the sample maker is opened, the two ends of the multiple aluminum shell plates are out of contact, and the locking aluminum sheets leak out until the hooks at the two ends of the locking aluminum sheets hook the two ends of the aluminum shell plates.

[0014] Furthermore, the sample preparation device is provided with 4 of the aforementioned retaining aluminum sheets and 4 of the aforementioned aluminum shell plates.

[0015] Furthermore, the top end of the hydraulic cylinder is fixed to the outer surface of the support rod, and the bottom end of the hydraulic cylinder is fixed to the outer surface of the aluminum shell plate of the sample maker.

[0016] Furthermore, the number of the hydraulic cylinders is 4, each of the hydraulic cylinders is provided with an oil filling port and an oil drain port, and the number of the oil filling port and the oil drain port is set to 1.

[0017] Furthermore, when the hydraulic cylinder injects oil through the oil filling port, the bottom end of the hydraulic cylinder extends out, causing the aluminum shell plate to move toward the geometric center direction of the supporting base until the two ends of the aluminum shell plate are connected to each other, and the sample maker completes the closing action; when the oil drain port of the hydraulic cylinder releases oil, the bottom end of the hydraulic cylinder retracts, causing the aluminum shell plate to move away from the geometric center direction of the supporting base, and the two ends of the aluminum shell plate are out of contact until the hook of the locking aluminum sheet hooks the two ends of the aluminum shell plate, and the sample maker completes the opening action.

[0018] Furthermore, the first end of the support rod is welded to the upper surface of the supporting base, the second end of the support rod is provided with an external thread, the second end of the support rod passes through the mounting hole opened in the top plate, and is fixedly connected by a retaining screw and a fixing screw, the upper surface of the retaining screw and the upper surface of the sample maker are located at the same horizontal position, and the lower surface of the fixing screw is in contact with the upper surface of the top plate.

[0019] Furthermore, the number of the support rods is set to 4, and the number of the mounting holes on the top plate is set to be consistent with the number of the support rods.

[0020] On the other hand, the present invention also provides a method for preparing a sample by homogenizing clay soil for geotechnical tests, wherein the method uses the device for preparing a sample by homogenizing clay soil for geotechnical tests provided by the present invention, and the method comprises the following steps:

[0021] S1: Remove the fixing screws and take down the top plate to expose the top of the sample preparation device;

[0022] S2: releasing oil through the oil drain port of the hydraulic cylinder to retract the bottom end of the hydraulic cylinder, thereby driving the sample preparation device to open;

[0023] S3: Weigh the soil mass according to the density of the sample to be prepared;

[0024] S4: pouring the weighed soil sample into the sample preparation device by natural sand falling method;

[0025] S5: injecting oil through the oil filling port of the hydraulic cylinder to extend the bottom end of the hydraulic cylinder and drive the sample preparation device to close;

[0026] S6: passing the mounting hole of the top plate through the bracket rod, so that the bottom surface of the top plate is closely fitted with the upper surface of the sample preparation device;

[0027] S7: Pass the fixing screw through the support rod and tighten it so that the lower surface of the fixing screw fits with the upper surface of the top plate;

[0028] S8: After waiting for 10 minutes, open the sample preparation device and take out the prepared soil sample.

[0029] The technical solution adopted in this application can achieve the following beneficial effects:

[0030] 1. The geotechnical test clay soil homogenization sample preparation device provided by the present invention has a hydraulic extrusion sample preparation system, reasonable design and simple installation;

[0031] 2. Compared with the traditional natural sand falling method, the sample preparation device provided by the present invention squeezes the remolded soil particles into the required cylindrical shape by annular extrusion, avoiding the uneven defect of the particles having a higher density at the bottom and a lower density at the top under the action of gravity;

[0032] 3. The present invention makes full use of the cohesive force of clay soil itself, and can prepare soil samples with the required density only by injecting and releasing oil from the hydraulic cylinder. The test operator does not come into direct contact with the sample, thus avoiding the uneven sand spreading caused by the traditional sample preparation method.

[0033] 4. The device and method for homogenizing and preparing samples of clay soil for geotechnical tests provided by the present invention have a simple overall operation process, a compact and convenient platform, and are easy to carry, disassemble and install.

[0034] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the three-dimensional structure of a sample preparation device according to an embodiment of the present invention;

[0036] Figure 2 It is a perspective schematic diagram of the internal three-dimensional structure of the sample preparation device according to an embodiment of the present invention;

[0037] Figure 3 It is a schematic top view of the sample preparation device of the embodiment of the present invention when the sample preparation device is closed;

[0038] Figure 4 It is a schematic top view of the sample preparation device of the embodiment of the present invention when the sample preparation device is opened;

[0039] Figure 5 Schematic diagram of the process of the sample preparation method according to an embodiment of the present invention.

[0040] The descriptions of the various numbers in the figure are as follows:

[0041] 1-bearing base, 2-bracket rod, 3-fixing screw, 4-top plate, 5-locking screw, 6-hydraulic cylinder, 7-locking aluminum sheet, 8-aluminum shell plate, 9-sample maker, 10-hydraulic cylinder oil filling port, 11-hydraulic cylinder oil drain port. DETAILED DESCRIPTION

[0042] The following describes several preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0043] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings.

[0044] like Figure 1 and Figure 2 As shown, the geotechnical test clay soil homogenization sample preparation device provided by the embodiment of the present invention, the support rod 2 is welded to the upper surface of the bearing base 1, the sample preparation device 9 is placed at the geometric center position of the upper surface of the bearing base 1, the retaining screw 5 and the fixing screw 3 are both installed on the rod body surface of the support rod 2; the top plate 4 passes through the support rod 2 through the hole, is installed on the upper surface of the sample preparation device 9, and is clamped between the retaining screw 5 and the fixing screw 3; the top end of the hydraulic cylinder 6 is welded to the outer surface of the support rod 2, and the bottom end of the hydraulic cylinder 6 is welded to the outer surface of the aluminum shell plate 8 of the sample preparation device 9. The sample preparation device provided by this embodiment is mainly used for the preparation of clay soil samples in the early preparation process of the experiment, and for preparing cylindrical clay samples that meet the uniformity requirements for indoor tests of geotechnical mechanics, in order to ensure the stability and reliability of subsequent soil mechanical properties determination.

[0045] Specifically, if Figure 1 and Figure 2 As shown, this embodiment provides a device for homogenizing and preparing samples of clay soil for geotechnical tests, including a bearing base 1, a sample preparation device 9, a hydraulic cylinder 6, a top plate 4 and a support rod 2, wherein:

[0046] The supporting base 1 is arranged at the bottom of the sample preparation device and is used to support the sample preparation device;

[0047] The sample preparation device 9 is installed on the upper surface of the bearing base 1. The sample preparation device 9 is connected to the support rod 2 through a hydraulic cylinder 6. A cylinder body is arranged inside the sample preparation device 9. The soil sample for geotechnical test is poured into the cylinder body of the sample preparation device 9 by a natural sand falling method.

[0048] The top end of the hydraulic cylinder 6 is fixed on the support rod 2, and the bottom end of the hydraulic cylinder 6 is fixed on the sample preparation device 9. The hydraulic cylinder 6 drives the sample preparation device 9 to move along the geometric center direction of the bearing base 1 to realize the opening and closing of the sample preparation device 9.

[0049] The top plate 4 is mounted on the upper surface of the sample preparation device 9 and is fixed by the support rod 2;

[0050] The first end of the support rod 2 is fixedly mounted on the upper surface of the bearing base, and the second end of the support rod 2 is fixedly connected to the top plate 4 .

[0051] like Figure 3 and Figure 4 As shown, the sample preparation device 9 is installed at the geometric center position of the upper surface of the supporting base 1. The sample preparation device 9 includes a clamping aluminum sheet 7 and an aluminum shell plate 8. The clamping aluminum sheet 7 is installed in the clamping groove inside the aluminum shell plate 8. The two ends of the clamping aluminum sheet 7 are provided with clamping hooks; the aluminum shell plate 8 constitutes the cylinder body of the sample preparation device. There are multiple clamping aluminum sheets 7 and aluminum shell plates 8, and the number is the same.

[0052] When the sample preparation device 9 is closed, the two ends of the plurality of aluminum shell plates 8 are connected in pairs, and the positioning aluminum sheet 7 is completely embedded in the card slot inside the aluminum shell plate 8 and cannot leak out. At the same time, the card hooks at the two ends of the positioning aluminum sheet 7 are also fitted in pairs. Figure 3 shown.

[0053] When the sample preparation device 9 is opened, the two ends of the plurality of aluminum shell plates 8 are out of contact and move away from the geometric center of the supporting base 1. At the same time, the positioning aluminum sheet 7 slides along the slot inside the aluminum shell plate 8 and leaks out until the hooks at the two ends of the positioning aluminum sheet 7 hook the two ends of the aluminum shell plate 8. Figure 4 shown.

[0054] In this embodiment, the sealing performance of the sample preparation device 9 is good whether it is closed or opened, which can ensure that the soil is not squeezed out from the two sides of the sample preparation device 9.

[0055] In this embodiment, the sample preparation device 9 is provided with four retaining aluminum sheets 7 and four aluminum shell plates 8 , which together achieve good sealing of the sample preparation device 9 .

[0056] like Figure 1 to Figure 4 As shown, the top end of the hydraulic cylinder 6 is fixed to the outer surface of the support rod 2, and the bottom end of the hydraulic cylinder 6 is fixed to the outer surface of the aluminum shell plate 8 of the sample maker 9. The hydraulic cylinder 6 drives the sample maker 9 to move along the geometric center direction of the supporting base 1 to realize the opening and closing of the sample maker 9.

[0057] In this embodiment, the number of hydraulic cylinders 6 is 4, each hydraulic cylinder 6 is provided with an oil filling port and an oil drain port, and the number of the oil filling port and the oil drain port is set to 1. Figure 2 As shown in the hydraulic cylinder oil filling port 10 and the hydraulic cylinder oil drain port 11.

[0058] In this embodiment, the hydraulic cylinder 6 drives the sample preparation device 9 to move along the geometric center direction of the supporting base 1 to realize the opening and closing of the sample preparation device 9. The details are as follows:

[0059] Closing operation of the sample preparation device 9: when the hydraulic cylinder 6 injects oil through the hydraulic cylinder oil filling port 10, the bottom end of the hydraulic cylinder 6 extends to move the aluminum shell plate 8 toward the geometric center direction of the bearing base 1 until the two ends of the aluminum shell plate 8 are connected in pairs, and the sample preparation device 9 completes the closing action;

[0060] Opening operation of the sample maker 9: When the hydraulic cylinder drain port 11 of the hydraulic cylinder 6 releases oil, the bottom end of the hydraulic cylinder 6 retracts, causing the aluminum shell plate 8 to move away from the geometric center direction of the supporting base 1, and the two ends of the aluminum shell plate 8 are out of contact until the hooks of the positioning aluminum sheet 7 hook the two ends of the aluminum shell plate 8, and the sample maker 9 completes the opening action.

[0061] like Figure 1 and Figure 2 As shown, in this embodiment, the first end of the support rod 2 is welded to the upper surface of the bearing base 1, and the second end of the support rod 2 is provided with an external thread. The second end of the support rod 2 passes through the mounting hole provided in the top plate 4 and is fixedly connected by the retaining screw 5 and the fixing screw 3. The upper surface of the retaining screw 5 is located at the same horizontal position as the upper surface of the sample preparation device 9, and the lower surface of the fixing screw 3 is in contact with the upper surface of the top plate. The external thread provided at the second end of the support rod 2 has a thread specification that matches the retaining screw 5 and the fixing screw 3.

[0062] In order to better support the sample preparation device provided in this embodiment, multiple support rods 2 are provided, which are respectively installed on both sides of the supporting base 1. A symmetrical arrangement can be adopted, and the positioning screws 5 and the fixing screws 3 are used in combination, and the number ensures the installation requirements of the support rods 2 and the top plate 4.

[0063] In this embodiment, the number of support rods 2 is set to 4, and the number of mounting holes on the top plate 4 is also set to 4. The diameter of the mounting hole can be set slightly larger than the outer diameter of the support rod 2 to facilitate the installation of the device.

[0064] like Figure 5 As shown, the present invention also provides a method for preparing homogenized clay samples for geotechnical tests. The method uses the sample preparation device provided by the present invention to prepare homogenized clay samples.

[0065] The sample preparation method provided in this embodiment comprises the following steps:

[0066] S1: Remove the top plate 4: Remove the fixing screws 3 and remove the top plate 4 to expose the top of the sample preparation device 9.

[0067] S2: Open the sample preparation device 9: release the oil through the hydraulic cylinder oil discharge port 11 of the hydraulic cylinder 6, so that the bottom end of the hydraulic cylinder 6 retracts, driving the sample preparation device 9 to open.

[0068] The oil is released through the hydraulic cylinder drain port 11 of the hydraulic cylinder 6, so that the bottom end of the hydraulic cylinder 6 retracts, thereby driving the aluminum shell plate 8 connected thereto to move in a direction away from the geometric center of the supporting base 1 until the hooks of the positioning aluminum sheet 7 hook the two ends of the aluminum shell plate 8, completing the opening operation of the sample preparation device 9.

[0069] S3: Weigh the soil mass according to the density of the sample to be prepared.

[0070] Weigh the soil mass according to the density of the sample to be prepared.

[0071] The soil mass is calculated using the following formula:

[0072]

[0073] Wherein, m is the mass of soil, ρ is the density of soil, V is the volume inside the sample preparation device 9, and d and h are the internal diameter and height of the sample preparation device 9 respectively.

[0074] S4: Pour the weighed soil sample into the sample preparation device 9 by using the natural sand falling method.

[0075] S5: closing the sample preparation device 9: injecting oil through the hydraulic cylinder oil filling port 10 of the hydraulic cylinder 6, so that the bottom end of the hydraulic cylinder 6 extends out, driving the sample preparation device 9 to close.

[0076] Oil is injected through the hydraulic cylinder oil filling port 10 of the hydraulic cylinder 6, so that the bottom end of the hydraulic cylinder 6 extends, thereby driving the aluminum shell plate 8 connected thereto to move toward the direction of the geometric center of the supporting base 1, and the hooks of the locking aluminum sheet 7 are out of contact with the two ends of the aluminum shell plate 8 until the two ends of the aluminum shell plate 8 are connected in pairs, and the sample maker 9 completes the closing operation.

[0077] S6: Pass the mounting hole of the top plate 4 through the bracket rod 2 so that the bottom surface of the top plate 4 is closely fitted with the upper surface of the sample preparation device 9.

[0078] S7: Pass the fixing screw 3 through the bracket rod 2 and tighten it so that the lower surface of the fixing screw 3 fits with the upper surface of the top plate 4;

[0079] S8: After waiting for 10 minutes, open the sample preparation device 9 and take out the prepared soil sample.

[0080] The soil samples prepared by the above preparation method are used for subsequent geotechnical tests, and ultimately cylindrical clay samples that meet the uniformity requirements are prepared for indoor geotechnical mechanics tests, in order to ensure the stability and reliability of subsequent soil mechanical property measurements.

[0081] Compared with the prior art, the device and method for homogenizing and preparing samples of clay soil for geotechnical tests provided by the present invention have the following advantages:

[0082] (1) The device for homogenizing and preparing samples of clay soil for geotechnical tests provided by the present invention has a hydraulic extrusion sample preparation system, is reasonably designed, and is easy to install;

[0083] (2) Compared with the traditional natural sand falling method, the sample preparation method provided by the present invention uses a circumferential extrusion method to extrude the remolded soil particles into the required cylindrical shape, thereby avoiding the uneven defect that the particles have a higher density at the bottom and a lower density at the top under the action of gravity;

[0084] (3) The present invention makes full use of the cohesive force of clay soil itself, and can prepare soil samples of required density only by injecting and releasing oil from the hydraulic cylinder. The test operator does not come into direct contact with the sample, thus avoiding the uneven sand spreading caused by traditional sample preparation methods.

[0085] (4) The overall operation process of the present invention is simple, the platform is compact and convenient to set up, and it is easy to carry, disassemble and install.

[0086] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A device for homogenizing and preparing samples of clay soil for geotechnical tests, characterized in that: It includes a bearing base, a sample preparation device, a hydraulic cylinder, a top plate and a support rod, wherein: The supporting base is arranged at the bottom of the sample preparation device and is used to support the sample preparation device; The sample maker is mounted on the upper surface of the bearing base, the sample maker is connected to the support rod through the hydraulic cylinder, a cylinder body is arranged inside the sample maker, and the soil sample for geotechnical test is poured into the cylinder body of the sample maker by natural sand falling method; The hydraulic cylinder, the top end of which is fixed on the support rod, and the bottom end of which is fixed on the sample maker, and the hydraulic cylinder drives the sample maker to move along the geometric center direction of the bearing base to realize the opening and closing of the sample maker; The top plate is mounted on the upper surface of the sample preparation device and is fixed by the support rod; The support rod, the first end of the support rod is fixedly mounted on the upper surface of the bearing base, and the second end of the support rod is fixedly connected to the top plate.

2. The sample preparation device according to claim 1, characterized in that: The sample maker is installed at the geometric center position of the upper surface of the supporting base. The sample maker includes a locking aluminum sheet and an aluminum shell plate. The locking aluminum sheet is installed in a slot inside the aluminum shell plate. Both ends of the locking aluminum sheet are provided with hooks. The aluminum shell plate constitutes the cylinder body of the sample maker.

3. The sample preparation device according to claim 2, characterized in that: There are multiple locking aluminum sheets and aluminum shell plates, and the number is the same; when the sample maker is closed, the two ends of the multiple aluminum shell plates are connected in pairs, and the locking aluminum sheets are completely embedded in the aluminum shell plates and cannot leak out; when the sample maker is opened, the two ends of the multiple aluminum shell plates are disengaged, and the locking aluminum sheets leak out until the hooks at the two ends of the locking aluminum sheets hook the two ends of the aluminum shell plates.

4. The sample preparation device according to claim 3, characterized in that: The sample preparation device is provided with 4 said clamping aluminum sheets and 4 said aluminum shell plates.

5. The sample preparation device according to claim 2, characterized in that: The top end of the hydraulic cylinder is fixed on the outer surface of the support rod, and the bottom end of the hydraulic cylinder is fixed on the outer surface of the aluminum shell plate of the sample maker.

6. The sample preparation device according to claim 5, characterized in that: The number of the hydraulic cylinders is 4, each of the hydraulic cylinders is provided with an oil filling port and an oil drain port, and the number of the oil filling port and the oil drain port is set to 1.

7. The sample preparation device according to claim 6, characterized in that: When the hydraulic cylinder injects oil through the oil filling port, the bottom end of the hydraulic cylinder extends out, causing the aluminum shell plate to move toward the geometric center direction of the supporting base until the two ends of the aluminum shell plate are connected to each other, and the sample maker completes the closing action; when the oil discharge port of the hydraulic cylinder releases oil, the bottom end of the hydraulic cylinder retracts, causing the aluminum shell plate to move away from the geometric center direction of the supporting base, and the two ends of the aluminum shell plate are out of contact until the hook of the locking aluminum sheet hooks the two ends of the aluminum shell plate, and the sample maker completes the opening action.

8. The sample preparation device according to claim 7, characterized in that: The first end of the support rod is welded to the upper surface of the supporting base, and the second end of the support rod is provided with an external thread. The second end of the support rod passes through the mounting hole opened in the top plate and is fixedly connected by a retaining screw and a fixing screw. The upper surface of the retaining screw is located at the same horizontal position as the upper surface of the sample maker, and the lower surface of the fixing screw is in contact with the upper surface of the top plate.

9. The sample preparation device according to claim 8, characterized in that: The number of the support rods is set to 4, and the number of the mounting holes on the top plate is set to be consistent with the number of the support rods.

10. A method for homogenizing clay soil samples for geotechnical tests, characterized in that: The sample preparation method uses the sample preparation device according to any one of claims 8 to 9, and the sample preparation method comprises the following steps: S1: Remove the fixing screws and take down the top plate to expose the top of the sample preparation device; S2: releasing oil through the oil drain port of the hydraulic cylinder to retract the bottom end of the hydraulic cylinder, thereby driving the sample preparation device to open; S3: Weigh the soil mass according to the density of the sample to be prepared; S4: pouring the weighed soil sample into the sample preparation device by natural sand falling method; S5: injecting oil through the oil filling port of the hydraulic cylinder to extend the bottom end of the hydraulic cylinder and drive the sample preparation device to close; S6: passing the mounting hole of the top plate through the bracket rod, so that the bottom surface of the top plate is closely fitted with the upper surface of the sample preparation device; S7: Pass the fixing screw through the support rod and tighten it so that the lower surface of the fixing screw fits with the upper surface of the top plate; S8: After waiting for 10 minutes, open the sample preparation device and take out the prepared soil sample.

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