An apparatus and method for preparing soil samples for anchored direct shear tests.

Abstract

This invention provides a soil sample preparation device and method for anchored direct shear tests, relating to the field of geotechnical testing. Addressing the problem that current soil sample preparation equipment struggles to prepare soil samples with reinforcement structures, this invention designs a matching sheath and ring cutter to contain the soil and prepare the soil sample under pressure. Furthermore, it allows for the insertion of a reinforcement structure during the compression process to jointly form a specimen for the anchored direct shear test. Simultaneous soil sample formation and reinforcement structure insertion avoid soil sample deformation or damage caused by inserting the reinforcement structure after sample formation, thus meeting the requirements of anchored direct shear tests and ensuring test accuracy.

Description

Technical Field

[0001] This invention relates to the field of geotechnical testing, and more specifically to a soil sample preparation apparatus and method for anchored direct shear tests. Background Technology

[0002] Shear strength parameters (cohesion and angle of internal friction) are among the most crucial mechanical parameters of soil and are indispensable for engineering stability calculations. Soil moisture content and void ratio significantly influence these parameters. Moisture content characterizes the degree of water absorption in the soil sample, while void ratio characterizes its compaction. Moisture content is relatively easy to control, but precise control of the void ratio requires precise control of the soil sample's compaction volume.

[0003] For engineering projects such as slope reinforcement and foundation pit support, soil nails and anchors can improve the properties of soil to a certain extent. The mechanical properties of anchored soil, especially its shear strength, provide valuable guidance for preventing engineering disasters such as slope and foundation pit instability. However, current field tests on the mechanical properties of anchored soil are heavily limited by environmental conditions, and altering soil parameters is difficult, making multi-parameter studies challenging for specific soil types. Chinese patent (publication number: CN216791799U) discloses a static compaction sampler for remolded soil, which presses soil samples into a ring cutter and demolds them to obtain soil samples that meet experimental requirements. However, this method does not meet the requirements for preparing anchored soil samples. During the process of obtaining soil samples and inserting them into reinforcement structures such as anchors, cracks may form in the soil samples, leading to sample damage or deformation. This makes it difficult to adapt to subsequent testing equipment, hindering experimental performance and affecting data. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a soil sample preparation device and method for anchored direct shear tests. This method involves designing a matching sheath and ring cutter to contain the soil and prepare the soil sample under pressure. A reinforcing structure can be inserted during the compression process to form the specimen for the anchored direct shear test. Simultaneous soil sample forming and reinforcing structure insertion avoids soil sample deformation or damage caused by inserting the reinforcing structure after sample forming, thus meeting the requirements of anchored direct shear tests and ensuring test accuracy.

[0005] The first objective of this invention is to provide a soil sample preparation device for anchored direct shear tests, employing the following scheme:

[0006] include:

[0007] The frame assembly includes a worktable, an upper top plate, and a telescopic component. The output end of the telescopic component drives the worktable to move to change the distance between the worktable and the upper top plate.

[0008] The mold assembly is arranged between the workbench and the top plate, including a sheath, a reinforcing structure, a ring cutter and a pressure-bearing column arranged coaxially. The pressure-bearing column has a central hole for one end of the pressure-bearing column to be inserted. The reinforcing structure slides with the central hole, and the ring cutter is coaxially arranged in the central hole.

[0009] After the central hole is filled with soil, the pressure column is driven by the pressure of the frame components to insert the reinforced structure into the ring cutter and simultaneously squeeze the soil into the ring cutter.

[0010] Furthermore, the central hole is a stepped hole, the outer wall of the ring cutter fits into the inner wall of the large-diameter section of the stepped hole, one end of the ring cutter abuts against the shoulder of the stepped hole, and the other end is flush with the end face of the sheath. The inner wall of the ring cutter and the small-diameter section of the stepped hole are connected to form a continuous compaction channel.

[0011] Furthermore, the reinforcement structure includes a mounting plate and several screws, one end of which is connected to a fixing plate. The mounting plate is slidably fitted with the small-diameter section of the stepped shaft, and the screws can be inserted into the soil inside the inner ring of the cutter ring.

[0012] Furthermore, the workbench is provided with a pad that supports the sheath and the ring cutter. The pad seals one end of the central hole and one end of the ring cutter. The pressure-bearing column is fitted to the opening at the end of the sheath away from the pad.

[0013] Furthermore, the pressure-bearing column includes a pressure-bearing part with a sliding fit central hole and an abutment part for contacting the upper top plate. The diameter of the abutment part is larger than the diameter of the pressure-bearing part, thereby limiting the movement of the pressure-bearing part relative to the central hole.

[0014] Furthermore, the frame assembly also includes a lower base plate, which is connected to the upper top plate by multiple parallel vertical rods. The worktable slides with the vertical rods through pre-set sliding holes along its edge, and the telescopic component is located between the lower base plate and the worktable.

[0015] Furthermore, the upper top plate, worktable, and lower bottom plate are arranged coaxially. A spring is fitted around the vertical rod between the worktable and the upper top plate. One end of the spring abuts against the worktable, and the other end abuts against the upper top plate. The telescopic component and the spring work together on the worktable.

[0016] Furthermore, the reinforcement structure adopts a scaled-down anchor bolt model, and the part of the reinforcement structure inserted into the ring cutter is configured according to the reinforcement components in the established soil sample.

[0017] A second objective of the present invention is to provide a working method utilizing a soil sample preparation apparatus for anchored direct shear tests as described in the first objective, comprising:

[0018] Using the volume of the ring cutter as the target volume of the soil sample, the required amount of material is calculated and the reinforcement structure is configured based on the target parameters.

[0019] The mold assembly is placed on the workbench, material is poured into the center hole of the sheath, and the reinforcing structure and pressure-bearing column are installed;

[0020] The telescopic component moves the worktable, causing the pressure column to squeeze the material in the central hole and push the reinforcing structure into the ring cutter.

[0021] After the soil is completely pressed into the ring cutter and the required portion of the soil for the reinforcement structure is inserted into the ring cutter, the position of the expansion joint is restored, and the soil sample, ring cutter, and reinforcement structure are removed from the sheath to obtain the specimen required for the direct shear test.

[0022] Furthermore, after the material is thoroughly mixed, it is fed into the central hole, and after the material is leveled, a pressing action is applied smoothly.

[0023] Compared with the prior art, the advantages and positive effects of this invention are:

[0024] (1) To address the problem that current soil sample preparation equipment is difficult to prepare soil samples with reinforcement structures, a matching sheath and ring cutter are designed to contain the soil and prepare the soil sample under pressure. The reinforcement structure can be inserted during the extrusion process to form a specimen for the anchored direct shear test. The soil sample is formed and the reinforcement structure is inserted simultaneously, avoiding the soil sample deformation or damage caused by inserting the reinforcement structure after the soil sample is formed. This meets the requirements of the anchored direct shear test and ensures the test accuracy.

[0025] (2) The inner diameter of the spring is larger than the diameter of the vertical rod, which can keep the worktable in the required horizontal position and avoid the tilting and offset problem caused by the worktable moving along the vertical rod. By using the spring to act on the worktable, the movement speed of the worktable along the vertical rod can be controlled, reducing the sudden change in the position of the worktable and ensuring the compaction effect.

[0026] (3) By using a specially designed sheath combined with a ring cutter as a mold, the void ratio of the soil sample can be precisely controlled, which greatly improves the test efficiency and the accuracy of the test results. By arranging the inner wall of the cutter and the inner wall of the small diameter section of the stepped hole with the same diameter, it can be ensured that a continuous compaction channel is formed in the sheath after the ring cutter is embedded, avoiding the formation of an obstacle structure at the ring cutter embedding position and improving the smoothness of the soil compaction process.

[0027] (4) The sum of the axial length of the bearing part and the thickness of the mounting plate along the axial direction is equal to the axial length of the small diameter section of the stepped hole in the sheath. After the soil is compacted, the end of the bearing part is attached to the mounting plate, and the end face of the mounting plate connecting screw is flush with the shoulder of the stepped hole, so that the soil is completely squeezed into the cutter, which can make the final compacted volume of the soil sample consistent with the volume of the cutter, thus improving the preparation accuracy of the soil sample. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0029] Figure 1 This is a schematic diagram of the soil sample preparation device used for anchored direct shear tests in Embodiments 1 and 2 of the present invention.

[0030] Figure 2 This is a front view of the soil sample preparation device used for anchored direct shear tests in Embodiments 1 and 2 of the present invention.

[0031] Figure 3 This is a schematic diagram of the structure of the upper top plate, lower bottom plate, and worktable with the vertical rod in embodiments 1 and 2 of the present invention.

[0032] Figure 4 This is a schematic diagram of the mold assembly in Embodiments 1 and 2 of the present invention.

[0033] Figure 5 This is a schematic diagram of the mounting plate in embodiments 1 and 2 of the present invention.

[0034] Figure 6 This is a schematic diagram of a single screw mounted on the mounting plate in embodiments 1 and 2 of the present invention.

[0035] Figure 7 This is a schematic diagram of two screws installed on the mounting plate in embodiments 1 and 2 of the present invention.

[0036] Figure 8 This is a schematic diagram of multiple screws arranged on the mounting plate in embodiments 1 and 2 of the present invention.

[0037] Among them, 1-vertical rod, 2-upper top plate, 3-workbench, 4-lower bottom plate, 5-jack, 6-spring, 7-pad plate, 8-ring cutter, 9-sheath, 10-anchor rod scale model, 11-screw, 12-mounting plate, 13-threaded connection hole, 14-pressure bearing column, 15-rubber washer, 16-nut. Detailed Implementation

[0038] Example 1

[0039] In a typical embodiment of the present invention, such as Figures 1-8 As shown, a soil sample preparation device for anchored direct shear tests is presented.

[0040] Current soil sample preparation equipment obtains reshaped soil samples by compressing and reshaping the input soil sample. However, the soil samples obtained are not suitable for engineering tests with reinforcement structures, such as slope reinforcement and foundation pit support. When conducting anchored direct shear tests, reinforcement structures need to be placed in the soil sample. However, after obtaining the existing soil sample, placing reinforcement structures such as soil nails and anchors can easily damage the soil sample, making it difficult to meet the requirements of the test. At the same time, placing reinforcement structures may cause deformation of the soil sample, resulting in changes in the size and specifications of the soil sample, making it unsuitable for subsequent test equipment and affecting the test process.

[0041] Based on this, this embodiment provides a soil sample preparation device for anchored direct shear tests, especially capable of obtaining soil samples with reinforcement structures to meet the needs of anchored soil research; by designing a matching sheath 9 and ring cutter 8 to contain the soil and prepare the soil sample under pressure, and by inserting the reinforcement structure during the compression process to form a specimen for anchored direct shear tests, the soil sample is formed and the reinforcement structure is inserted simultaneously, avoiding soil sample deformation or damage caused by inserting the reinforcement structure after the soil sample is formed, meeting the requirements of anchored direct shear tests and ensuring test accuracy.

[0042] The soil sample preparation device for the anchored direct shear test described above will now be explained in detail with reference to the accompanying drawings.

[0043] See Figure 1 The soil sample preparation device for the anchored direct shear test includes a frame assembly and a mold assembly. The frame assembly can support and drive the mold assembly, carry the mold assembly and drive the mold assembly to move, so that the mold assembly can compact and squeeze the soil inside to form a soil sample.

[0044] The frame assembly includes an upper top plate 2, a worktable 3, a telescopic mechanism, and a lower bottom plate 4 arranged vertically in sequence. The upper top plate 2 is connected to the lower bottom plate 4 by multiple parallel vertical rods 1. The worktable 3 slides with the vertical rods 1 through pre-set sliding holes on its edge. The output end of the telescopic mechanism is connected to the worktable 3 to drive the worktable 3 to move along the axis of the vertical rods 1 and adjust the distance between the worktable 3 and the upper top plate 2.

[0045] Optionally, the connection between the vertical rod 1 and the upper top plate 2 and lower bottom plate 4 can be either a detachable connection or a fixed connection. In this embodiment, using... Figure 1 The diagram shows an example of using three vertical rods 1 to connect the upper top plate 2 and the lower bottom plate 4. One end of the vertical rod 1 is provided with a threaded section, which connects to a pre-set threaded hole on the lower bottom plate 4. The other end of the vertical rod 1 is provided with a stepped shaft section and a threaded section. The vertical rod 1 engages with a pre-set through hole on the upper top plate 2 through the stepped shaft. After the threaded section passes through the upper top plate 2, a nut 16 is fitted. The nut 16 engages with the threaded section to press the upper top plate 2 against the shoulder of the stepped shaft section, thus locking the relative position between the upper top plate 2 and the vertical rod 1.

[0046] In addition, a rubber washer 15 can be installed at the mating position of the nut 16 to improve the fastening stability.

[0047] In this embodiment, three vertical rods 1 are distributed around the axis of the entire frame assembly, and the edge of the workbench 3 is provided with sliding holes that correspond one-to-one with the vertical rods 1; it can be understood that the bottom surface of the upper top plate 2 is perpendicular to the axis of the vertical rods 1, and the top surface of the lower bottom plate 4 is also perpendicular to the axis of the vertical rods 1.

[0048] like Figure 2 , Figure 3 As shown, the vertical rod 1 can be a cylindrical smooth rod, allowing the worktable 3 to slide smoothly along the axial direction of the vertical rod 1. At the same time, a spring 6 is installed on the sleeve of the vertical rod 1 between the worktable 3 and the upper top plate 2. One end of the spring 6 abuts against the worktable 3, and the other end abuts against the upper top plate 2. The telescopic component and the spring 6 work together to move the worktable 3 back and forth along the axial direction of the vertical rod 1, which meets the requirements for preparing soil samples.

[0049] Optionally, the upper top plate 2, the worktable 3, and the lower bottom plate 4 can be configured as circular plates with the same diameter and thickness. The upper top plate 2 has through holes adapted to connect the vertical rod 1, the lower bottom plate 4 has threaded holes for mounting the vertical rod 1, and the worktable 3 has sliding holes for the vertical rod 1 to pass through. Multiple through holes, threaded holes, and sliding holes are provided, with the specific number adapted to the number of vertical rods 1. The distribution of the through holes, threaded holes, and sliding holes is determined based on the distribution of the vertical rods 1.

[0050] The telescopic components adopt telescopic elements that are easy to control, such as linear drive mechanisms like cylinders, hydraulic cylinders, and electric cylinders. Optionally, taking a vertical hydraulic jack 5 as an example, it is installed on the lower base plate 4 with its output end facing the worktable 3. The movement of the output end drives the worktable 3 to move.

[0051] The output end of the vertical hydraulic jack 5 can act on the center position of the workbench 3, and its output force can meet the needs of compacting and densifying the soil.

[0052] The inner diameter of the spring 6 is larger than the diameter of the vertical rod 1, which can keep the worktable 3 in the required horizontal position and avoid the tilting and offset problem that occurs when the worktable 3 moves along the vertical rod 1. By using the spring 6 to act on the worktable 3, the movement speed of the worktable 3 along the vertical rod 1 can be controlled, reducing the sudden changes in the position of the worktable 3 and ensuring the compaction effect.

[0053] The mold assembly is located in the pressure zone between the worktable 3 and the upper top plate 2, such as Figure 2 , Figure 3As shown, the mold assembly includes a sheath 9, a ring cutter 8, and a pressure-bearing column 14. The ring cutter 8 is coaxially embedded in the central hole of the sheath 9. The interior of the ring cutter 8 and the interior of the sheath 9 together form a compaction channel for filling the soil. The pressure-bearing column 14 is provided with a pressure-bearing part, which can be inserted axially into the compaction channel from one end of the compaction channel to contact and squeeze the soil in the compaction channel.

[0054] The end of the pressure-bearing column 14 away from the pressure-bearing part is used to contact the upper top plate 2. As the telescopic component lifts the work platform 3, the upper top plate 2 applies a reaction force to the pressure-bearing column 14, thereby causing the pressure-bearing column 14 to apply pressure to the soil in the compaction channel.

[0055] The ring cutter 8 is located at one end of the central hole, with one end face of the ring cutter 8 inside the central hole and the other end face flush with the end face of the sheath 9. This flush surface contacts the pad 7, which seals one end of the compaction channel. The other end of the compaction channel is sealed by the pressure-bearing column 14. After both ends of the compaction channel are sealed, the soil in the compaction channel is squeezed as the pressure-bearing part of the pressure-bearing column 14 moves within the compaction channel. After the required compaction density is achieved, the required soil sample is obtained.

[0056] In actual use, the pad 7 is placed on the top surface of the workbench 3 and faces the upper top plate 2. The end faces of the ring cutter 8 and the protective sleeve 9 are flush with each other and placed on the pad 7. At the same time, in order to ensure stability during the extrusion process, the ring cutter 8, the protective sleeve 9 and the workbench 3 are arranged coaxially.

[0057] In this embodiment, for preparing soil samples with reinforcement structures, an anchor rod scale model 10 is configured as the reinforcement structure. The anchor rod scale model 10 can slide and cooperate with the compaction channel. When the pressure-bearing column 14 pushes the anchor rod scale model 10, the anchor rod scale model 10 can be partially inserted into the soil and squeeze the soil.

[0058] Specifically, regarding the fit between the sheath 9 and the ring cutter 8, the sheath 9 has a cylindrical structure with a stepped central hole. The ring cutter 8 is embedded in the large-diameter section of the stepped hole, and the axial lengths of the ring cutter 8 and the large-diameter section of the stepped hole are equal. For example... Figure 4 As shown, the outer wall of the ring cutter 8 can fit into the inner wall of the large-diameter section of the stepped hole. The inner diameter of the ring cutter 8 is equal to that of the inner wall of the small-diameter section of the stepped hole. After the ring cutter 8 is embedded in the stepped hole, the inner wall of the ring cutter 8 connects with the inner wall of the small-diameter section of the stepped hole, forming a compaction channel of equal diameter.

[0059] By arranging the inner wall of the cutter replacement and the inner wall of the small-diameter section of the stepped hole with the same diameter, it can be ensured that a continuous compaction channel is formed in the sheath 9 after the ring cutter 8 is embedded, avoiding the formation of an obstacle structure at the embedding position of the ring cutter 8 and improving the smoothness of the soil compaction process.

[0060] Optionally, the ring cutter 8 can be a non-side-type ring cutter 8, with specifications and dimensions conforming to industry standards. The sheath 9 can be made of a transparent material, such as transparent acrylic, which facilitates observation of the soil within the compaction channel during the compaction process.

[0061] The ring cutter 8 can be embedded in the sheath 9. After the soil is compacted to the required standard in the compaction channel, the ring cutter 8 and the soil sample can be removed from the sheath 9 together, reducing the damage caused by directly demolding the soil sample.

[0062] By using a specially designed sheath 9 combined with a ring cutter 8 as a mold, the void ratio of the soil sample can be precisely controlled, greatly improving the test efficiency and the accuracy of the test results; indoor tests can be conducted using a scaled-down anchor rod model 10 to study the mechanical properties of the anchored soil.

[0063] like Figures 4-8 As shown, the reinforcement structure adopts the anchor bolt scale model 10. The anchor bolt scale model 10 includes a screw 11 and a mounting plate 12. The screw 11 is used to simulate the anchor bolt. One end of the screw 11 has a threaded section that connects to the mounting plate 12. The threaded mounting plate 12 is provided with a threaded connection hole 13 that matches the threaded section of the screw 11.

[0064] Optionally, the mounting plate 12 can slide within the compaction channel. The diameter of the mounting plate 12 is configured to be the same as the diameter of the compaction channel, that is, the diameter of the mounting plate 12 is equal to the diameter of the small diameter section of the stepped hole and the diameter of the inner wall of the ring cutter 8. After the mounting plate 12 is installed in the compaction channel, it can move smoothly along the axial direction of the compaction channel.

[0065] The mounting plate 12 is provided with multiple threaded connection holes 13. The distribution of the threaded connection holes 13 corresponds to the distribution of the anchor rods in the simulated anchored soil. The screw rods 11 are arranged according to the distribution of the anchor rods in the simulated anchored soil. One screw rod 11, two screw rods 11, or multiple screw rods 11 can be arranged.

[0066] In this embodiment, five threaded connection holes 13 are provided on the mounting plate 12. One of the threaded connection holes 13 is located at the center of the mounting plate 12. It and the other four threaded connection holes 13 are evenly arranged circumferentially along the threaded holes at the center. After the screw 11 is installed in the threaded connection hole 13, the screw 11 is connected to the mounting plate 12 as a whole.

[0067] The pressure-bearing part of the pressure-bearing column 14 is a columnar structure and is adapted to the compaction channel. The pressure-bearing column 14 also includes an abutment part, the diameter of which is larger than the diameter of the pressure-bearing part, to limit the movement of the pressure-bearing part relative to the compaction channel.

[0068] It should be noted that the sum of the axial length of the bearing part and the axial thickness of the mounting plate 12 is equal to the axial length of the small-diameter section of the stepped hole inside the sheath 9. After the soil is compacted, the end of the bearing part is attached to the mounting plate 12, and the end face of the connecting screw 11 of the mounting plate 12 is flush with the shoulder of the stepped hole, thereby completely squeezing the soil into the cutter head, so that the final compacted volume of the soil sample is consistent with the volume of the cutter head.

[0069] It is evident that when preparing soil samples with reinforced structures, the insertion process of the end of the screw 11 away from the mounting plate 12 into the soil is carried out simultaneously with the compaction process of the mounting plate 12 on the soil. This ensures that the screw 11 is firmly inserted into the soil sample during the compaction process, avoiding the problem of difficulty in inserting the screw 11 after preparing the soil sample, which could lead to cracks in the specimen.

[0070] Meanwhile, when compacting the soil to obtain anchored soil specimens with reinforced structures, the size of the specimens will not change significantly due to the insertion of screw 11, thus making them compatible with direct shear test equipment. After the specimens are made, subsequent operations can be carried out according to the normal procedures for direct shear tests.

[0071] The entire soil sample preparation device for the anchored direct shear test is easy to assemble and disassemble and can be reused. In other embodiments, the compaction operation required for other tests can be adapted by changing the mold components.

[0072] Example 2

[0073] In another typical embodiment of the present invention, such as Figures 1-8 As shown, a working method is presented.

[0074] Using the soil sample preparation apparatus for anchored direct shear tests as described in Example 1, the following steps are included:

[0075] Using the volume of the ring cutter 8 as the target volume of the soil sample, the required amount of material is calculated and the reinforcement structure is configured based on the target parameters.

[0076] The mold assembly is placed on the workbench 3, material is put into the center hole of the sheath 9, and the reinforcing structure and pressure-bearing column 14 are installed;

[0077] The telescopic component moves the worktable 3, causing the pressure column 14 to squeeze the material in the center hole and push the reinforcing structure part into the ring cutter 8;

[0078] After the soil is completely pressed into the ring cutter 8 and the soil required for the reinforcement structure is inserted into the ring cutter 8, the position of the expansion joint is restored, and the soil sample, ring cutter 8 and reinforcement structure are removed from the sheath 9 to obtain the sample required for the direct shear test.

[0079] Specifically, in combination Figures 1-8Example 1 describes the working method of the soil sample preparation device used for anchored direct shear tests.

[0080] (1) Frame assembly. Align the three vertical rods 1 with the threaded holes on the lower base plate 4 and tighten them. Then place the jack 5 on the lower base plate 4. Next, put the workbench 3 on the vertical rods 1 and adjust the position of the jack 5 so that its top is embedded in the groove at the bottom of the workbench 3. Then, put the three springs 6 on the vertical rods 1 and put the upper top plate 2 on the vertical rods 1. Finally, put the rubber washer 15 on the part of the vertical rods 1 that extends out of the upper top plate 2 and tighten the nut 16 that corresponds to the thread size of the upper part of the vertical rods 1.

[0081] (2) Assembly of the anchor bolt scaled-down model 10. Determine the number of bolts 11 according to the specific test requirements. Insert the threaded end of the bolt 11 into the corresponding threaded connection hole 13 on the mounting plate 12 and tighten it. If only a normal direct shear test is to be performed, bolts 11 are not required. To prevent the soil sample from clogging the unused threaded connection hole 13 during the test, transparent tape can be used to stick the unused threaded connection hole 13. Since the interaction between the soil sample and the bolt 11 during shearing will cause the bolt 11 to bend to varying degrees, the bent bolt 11 should be removed first and then a new bolt 11 should be installed before the next test.

[0082] (3) Soil sample preparation. The target volume of the soil sample is the volume of the ring cutter 8. The required mass of soil and water is calculated based on the target moisture content and void ratio. The soil and water are thoroughly mixed to obtain the required soil sample.

[0083] (4) Compaction mold assembly. Place the ring cutter 8 on the pad 7 and put the acrylic sheath 9 on the ring cutter 8. Then pour the prepared soil into the sheath 9 and gently tap the side wall of the sheath 9 to make the soil slightly compacted and the surface flat. Then, align the anchor rod scale model 10 with the screw 11 facing down and put it into the sheath 9. Finally, put the pressure column 14 on top.

[0084] (5) Compacting the soil sample. Place the above-mentioned compaction mold on the workbench 3 and position the mold in the center of the workbench 3. Tighten the oil valve of the jack 5, attach the handle, and shake the handle up and down to make the workbench 3 rise slowly and steadily under the action of the jack 5. Then, the screw 11 is firmly inserted into the soil sample during the compaction process. Stop shaking the handle when the upper part of the pressure column 14 contacts the upper part of the acrylic sheath 9.

[0085] (6) Remove the ring cutter 8. Loosen the oil valve of the jack 5 to allow the workbench 3 to slowly descend, remove the pressure column 14 and acrylic sleeve 9, remove the ring cutter 8 with the anchor rod scale model 10, and then proceed with the subsequent operations according to the normal procedures for the direct shear test.

[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A soil sample preparation device for anchored direct shear tests, characterized in that, include: The frame assembly includes a worktable, an upper top plate, and a telescopic component. The output end of the telescopic component drives the worktable to move, thereby changing the distance between the worktable and the upper top plate. The frame assembly also includes a lower base plate, which is connected to the upper top plate via multiple parallel vertical rods. The worktable slides with the vertical rods through pre-set sliding holes along its edges. The telescopic component is located between the lower base plate and the worktable. The upper top plate, worktable, and lower base plate are arranged coaxially. A spring is fitted around the vertical rod between the worktable and the upper top plate. One end of the spring abuts against the worktable, and the other end abuts against the upper top plate. The telescopic component and the spring work together on the worktable. The mold assembly, located between the workbench and the top plate, includes a coaxially arranged sheath, a reinforcing structure, a ring cutter, and a pressure-bearing column. The ring cutter is coaxially embedded in the central hole of the sheath, and the interior of the ring cutter and the interior of the sheath together form a compaction channel for the filling soil. The pressure-bearing column is provided with a pressure-bearing part, which can extend axially into the compaction channel from one end of the compaction channel. The reinforcing structure slides in fit with the central hole. After the central hole is filled with soil, the pressure column is driven by the pressure of the frame assembly to insert the reinforcement structure into the ring cutter and simultaneously squeeze the soil into the ring cutter; the reinforcement structure includes a mounting plate and several screws, one end of the screw is connected to the fixing plate, the mounting plate slides with the small diameter section of the stepped shaft, and the screw can be inserted into the soil inside the inner ring of the ring cutter.

2. The soil sample preparation device for anchored direct shear tests as described in claim 1, characterized in that, The central hole is a stepped hole. The outer wall of the ring cutter fits into the inner wall of the large-diameter section of the stepped hole. One end of the ring cutter abuts against the shoulder of the stepped hole, and the other end is flush with the end face of the sheath. The inner wall of the ring cutter connects with the small-diameter section of the stepped hole to form a continuous compaction channel.

3. The soil sample preparation device for anchored direct shear tests as described in claim 1, characterized in that, The workbench is provided with a pad that supports the sheath and the ring cutter. The pad seals one end of the central hole and one end of the ring cutter. The pressure-bearing column is fitted to the opening at the end of the sheath away from the pad.

4. The soil sample preparation device for anchored direct shear test as described in claim 3, characterized in that, The pressure-bearing column includes a pressure-bearing part with a sliding fit central hole and an abutment part for contacting the upper top plate. The diameter of the abutment part is larger than the diameter of the pressure-bearing part, thereby limiting the movement of the pressure-bearing part relative to the central hole.

5. The soil sample preparation device for anchored direct shear tests as described in claim 1, characterized in that, The reinforcement structure adopts a scaled-down anchor bolt model, and the part of the reinforcement structure inserted into the ring cutter is configured according to the reinforcement components in the established soil sample.

6. A working method, utilizing the soil sample preparation apparatus for anchored direct shear tests as described in any one of claims 1-5, characterized in that, include: Using the volume of the ring cutter as the target volume of the soil sample, the required amount of material is calculated and the reinforcement structure is configured based on the target parameters. The mold assembly is placed on the workbench, material is poured into the center hole of the sheath, and the reinforcing structure and pressure-bearing column are installed; The telescopic component moves the worktable, causing the pressure column to squeeze the material in the central hole and push the reinforcing structure into the ring cutter. After the soil is completely pressed into the ring cutter and the required portion of the soil for the reinforcement structure is inserted into the ring cutter, the position of the expansion joint is restored, and the soil sample, ring cutter, and reinforcement structure are removed from the sheath to obtain the specimen required for the direct shear test.

7. The working method as described in claim 6, characterized in that, After the material is thoroughly mixed, it is put into the central hole, and after the material is leveled, a pressing action is applied smoothly.

Images