A direct shear test device for studying the interface action characteristics of rock-soil

Abstract

This utility model discloses a direct shear test device for studying the interaction characteristics of soil-rock interfaces. It includes an experimental platform with a lower shear box mounted on its upper side. An upper shear box is slidably connected to the upper side of the lower shear box. The upper side of the experimental platform is equipped with a horizontal shearing component for pulling the upper shear box horizontally left and right, and a normal shearing component for applying normal shear force to the upper and lower shear boxes. A discharge chamber is opened on the front side of the experimental platform, containing a conveying component for loading and unloading materials. The horizontal and normal shearing components also contain detection components for monitoring experimental data. The horizontal and normal shearing components achieve a direct shear effect on the experimental soil within the upper shear box. Furthermore, the normal shearing component can synchronously displace with the action of the horizontal shearing component, ensuring constant stress at the shear surface and providing a stable stress environment for the experiment.

Description

Technical Field

[0001] This utility model belongs to the field of large-scale direct shear test technology for soil and rock, and relates to a direct shear test device for studying the characteristics of soil-rock interface interaction. Background Technology

[0002] Direct shear testing, a widely used method in geotechnical engineering, is of great significance for determining the shear strength parameters of materials such as soil or rock. These parameters play a crucial role in assessing foundation bearing capacity, slope stability, and the stability of various civil engineering structures. However, while traditional direct shear testing apparatuses have provided a wealth of fundamental data for engineering practice over a long period of use, some limitations have gradually become apparent.

[0003] Traditional direct shear testing apparatuses typically lack a robust overall stabilization servo system, making it difficult to guarantee stability during testing, especially during loading. Most traditional apparatuses have an upper shear box slightly smaller than the lower shear box in an attempt to maintain normal force stability during direct shear. However, this design limits the size of the upper shear box, preventing long-stroke direct shear tests. This, in turn, affects the accuracy and reliability of the test results, failing to accurately reflect the actual shear strength characteristics of the soil and negatively impacting engineering design and stability assessments based on test data.

[0004] Most existing direct shear tests are non-visual operations. During the test, key information such as soil deformation, crack development, and stress distribution cannot be directly observed and recorded. This greatly limits researchers' in-depth understanding of the mechanical behavior and failure mechanism of soil during shearing. The lack of visualization methods makes it difficult to capture the intrinsic relationship between changes in the soil's internal microstructure and its macroscopic mechanical response, hindering the comprehensive analysis and interpretation of direct shear test results and making it difficult to study the manifestation of complex soil properties such as the rheological properties of soft soil and the swelling and shrinkage properties of expansive soil during shearing.

[0005] Chinese utility model patent CN203053799U discloses a large-scale direct shearing machine, which includes a base plate and a shearing box located on the base plate, an upper shearing box and a lower shearing box, and further includes a top baffle, a pair of columns, a horizontal hydraulic power device and a vertical hydraulic power device. The columns are fixed to the base plate and are located on both sides of the shearing box. The top baffle is fixed to the upper end of the columns. The vertical hydraulic power device is fixed above the shearing box and to the lower surface of the top baffle. The horizontal hydraulic power device is fixed to the side of the shearing box. The technical solution utilizes a simple structure consisting of a top baffle, a column, a base plate, and a tie rod to withstand the internal forces of the equipment. Vertically, a vertical hydraulic power device pushes the movable cover plate on the top surface of the shearing box to apply vertical pressure to the sample. Laterally, a horizontal hydraulic power device pushes the lower shearing box to slide along the first guide rail. The friction between the upper and lower shearing boxes is reduced by rollers on both sides of the lower shearing box and second guide rails on both sides of the upper shearing box. During shearing, the upper shearing box is kept stationary by a bent arm positioned between the column and the rear baffle of the upper shearing box. This achieves the experimental process of vertically pressurizing and horizontally shearing the sample.

[0006] The aforementioned technical solutions cannot guarantee the stability of the loading process. This may stem from the limited precision and control capabilities of the loading equipment itself, or insufficient stiffness of the loading system. Unstable loading can cause fluctuations and abrupt changes in the shear force experienced by the soil sample, leading to uneven stress distribution within the sample and premature local failure. Therefore, the shear strength parameters obtained from the experiment may be too low or too high, inconsistent with actual engineering conditions. This instability during the loading process not only reduces the quality of the experimental data but may also lead to premature sample failure, making it impossible to fully obtain the mechanical property curves of the soil at different shear stages, thus affecting the study of the shear strength growth law and failure mode of the soil. Utility Model Content

[0007] To address the aforementioned problem of difficulty in ensuring stability during the loading process, this invention proposes a direct shear test device for studying the interaction characteristics of the soil-rock interface, which effectively solves the problem of difficulty in ensuring stability during the loading process in the prior art.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] A direct shear test apparatus for studying the characteristics of rock-soil interface interactions includes an experimental platform. A lower shear box is disposed on the upper side of the experimental platform, and an upper shear box is slidably connected to the upper side of the lower shear box. A horizontal shearing component for pulling the upper shear box horizontally to the left and right and a normal shearing component for applying normal shear force to the upper and lower shear boxes are disposed on the upper side of the experimental platform. A discharge chamber is opened on the front side of the experimental platform, and a conveying component for loading and unloading materials is disposed in the discharge chamber. Detection components for detecting experimental data are also disposed in the horizontal shearing component and the normal shearing component.

[0010] Furthermore, the horizontal shearing assembly includes a fixed base disposed on the side of the experimental platform, the fixed base being located on one side of the lower shearing box, a horizontal telescopic motor being disposed on the upper side of the fixed base, and a pull block being disposed on the side of the upper shearing box and connected to the output shaft of the horizontal telescopic motor.

[0011] Furthermore, a guide platform is provided on the side of the experimental platform between the lower shear box and the fixed seat, and a sliding groove is provided on the side of the guide platform to allow the upper shear box to slide left and right.

[0012] Furthermore, the normal shearing assembly includes four fixed columns arranged in a rectangular array on the side of the experimental platform. A top plate is provided on the upper side of the four fixed columns. A translation plate is slidably connected to the upper side of the top plate. A normal telescopic motor is provided on the upper side of the translation plate. Connecting columns connected to the lower side of the translation plate are provided at the four corners of the upper side of the upper shearing box. A pressure plate is slidably connected to the upper shearing box. The output shaft of the normal telescopic motor passes through the translation plate and is fixedly connected to the upper side of the pressure plate.

[0013] Furthermore, the conveying assembly includes a hydraulic lift disposed in the discharge chamber, and a material box is disposed on the output shaft of the hydraulic lift, the material box being inserted into the lower shear box under the push of the hydraulic lift.

[0014] Furthermore, the front side of the discharge chamber has two cabinet doors that are symmetrically hinged to each other.

[0015] Furthermore, the detection assembly includes a pressure sensor and a normal displacement sensor disposed within the pressure plate, and a tension sensor and a horizontal displacement sensor disposed within the pull block. A display screen is disposed on the side of the experimental platform, and the display screen is electrically connected to the pressure plate sensor, the normal displacement sensor, the tension sensor, and the horizontal displacement sensor.

[0016] Furthermore, transparent protective plates are symmetrically arranged on the front sides of the upper and lower shear boxes, and the transparent protective plates on the upper and lower shear boxes can cooperate to form an observation window that allows observation of the internal conditions of the upper shear box and the lower detection box.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention achieves a direct shearing effect on the experimental soil in the upper shear box through a horizontal shearing component and a normal shearing component. The normal shearing component can move synchronously with the action of the horizontal shearing component, ensuring constant stress at the shearing surface and providing a stable stress environment for the test. This constant normal stress effectively avoids the adverse effects that normal stress fluctuations may have on the test results, ensuring the accuracy and reliability of the test data.

[0019] The testing components enable the testing, transmission, and display of normal pressure, normal displacement, horizontal tension, and horizontal displacement, improving the convenience for experimental personnel when recording and analyzing data. The conveying components enable the rapid replacement of experimental soil, further enhancing the convenience for experimental personnel when using the device.

[0020] The observation window formed by the two transparent protective plates allows for direct observation of the deformation and failure process inside the soil sample, providing researchers with abundant visual information. At the same time, the cabinet door can seal the discharge chamber, thus protecting the inside of the discharge chamber and improving the safety of the device. The guide platform further ensures the stability of the upper shear box when sliding left and right, preventing the upper shear box from deviating when sliding left and right, and ensuring the reliability of the device during use. Attached Figure Description

[0021] Figure 1 This is a perspective view of the present utility model;

[0022] Figure 2 This is a schematic diagram of the structure of this utility model;

[0023] Figure 3 This utility model Figure 2 A magnified view of part A.

[0024] In the diagram: 1. Experimental table; 101. Discharge chamber; 2. Fixed column; 3. Top plate; 4. Lower shear box; 5. Upper shear box; 6. Connecting column; 7. Translation plate; 8. Normal telescopic motor; 9. Fixed seat; 10. Horizontal telescopic motor; 11. Pull block; 12. Display screen; 13. Transparent protective plate; 14. Cabinet door; 15. Pressure plate; 16. Guide table; 17. Hydraulic lift; 18. Pressure sensor; 19. Normal displacement sensor; 20. Tension sensor; 21. Horizontal displacement sensor; 22. Material box. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example 1

[0026] like Figure 1 , Figure 2 as well as Figure 3 As shown, a direct shear test device for studying the interaction characteristics of soil-rock interfaces includes an experimental platform 1. A lower shear box 4 is bolted to the upper side of the experimental platform 1. An upper shear box 5 is slidably connected to the upper side of the lower shear box 4. The upper side of the experimental platform 1 is provided with a horizontal shearing component for pulling the upper shear box 5 horizontally to slide left and right, and a normal shearing component for applying normal shear force to the upper shear box 5 and the lower shear box 4. A discharge chamber 101 is opened on the front side of the experimental platform 1. A conveying component for feeding and discharging materials is provided in the discharge chamber 101. Detection components for detecting experimental data are also provided in the horizontal shearing component and the normal shearing component.

[0027] In this embodiment, the horizontal shearing assembly includes a fixed seat 9 that is bolted to the upper side of the experimental table 1. The fixed seat 9 is located on one side of the lower shearing box 4. A horizontal telescopic motor 10 is bolted to the upper side of the fixed seat 9. A pull block 11 connected to the output shaft of the horizontal telescopic motor 10 is provided on the side of the upper shearing box 5.

[0028] In this embodiment, the normal shearing assembly includes four fixed columns 2 arranged in a rectangular array on the upper side of the experimental platform 1. A top plate 3 is provided on the upper side of the four fixed columns 2. A translation plate 7 is slidably connected to the upper side of the top plate 3. A normal telescopic motor 8 is provided on the upper side of the translation plate 7. Connecting columns 6 are provided at the four corners of the upper side of the upper shearing box 5 and connected to the lower side of the translation plate 7. A pressure plate 15 is slidably connected to the upper side of the upper shearing box 5. The output shaft of the normal telescopic motor 8 passes through the translation plate 7 and is fixedly connected to the upper side of the pressure plate 15.

[0029] In this embodiment, the conveying assembly includes a hydraulic lift 17 disposed in the discharge chamber 101. A material box 22 is disposed on the output shaft of the hydraulic lift 17. The material box 22 can be inserted into the lower shear box 4 under the push of the hydraulic lift 17.

[0030] In this embodiment, the detection components include a pressure sensor 18 and a normal displacement sensor 19 disposed in the pressure plate 15, and a tension sensor 20 and a horizontal displacement sensor 21 disposed in the pull block 11. A display screen 12 is disposed on the upper side of the experimental platform 1, and the display screen 12 is electrically connected to the pressure plate 15 sensor, the normal displacement sensor 19, the tension sensor 20 and the horizontal displacement sensor 21.

[0031] The working principle of this embodiment is as follows:

[0032] During the direct shear test, the soil sample is first placed in the material box 22 of the conveying assembly, ensuring the sample surface is flat. Then, under the action of the hydraulic lift 17, the material box 22 moves upward and inserts into the lower shear box 4. Next, the normal telescopic motor 8 presses down the pressure plate 15, applying a set normal force to the soil sample. During the normal loading process, the normal displacement sensor 19 and the pressure sensor 18 monitor the changes in the normal displacement and pressure of the pressure plate 15 in real time and transmit the data to the display screen 12 for recording and analysis by the staff. When the normal force reaches the set value and remains stable, the horizontal telescopic motor 10 starts working, pulling the upper shear box 5 horizontally via the pull block 11, thus achieving the shearing action on the soil sample. During the shearing process, the horizontal displacement sensor 21 and the tension sensor 20... The system monitors the changes in horizontal displacement and tension of the upper shear box 5 and transmits the data to the display screen 12. During this process, the normal telescopic motor 8 can precisely control the normal stress to ensure that the stress at the shear surface is constant, providing a stable stress environment for the experiment. This constant normal stress effectively avoids the adverse effects that fluctuations in normal stress may have on the test results, ensuring the accuracy and reliability of the test data. After the test is completed, the normal telescopic motor 8 and the horizontal telescopic motor 10 are controlled to return to their original positions. At this time, the upper shear box 5 and the pressure plate 15 move to their initial positions. Finally, the hydraulic lift 17 is controlled again to move the material box 22 downward, so that the material box 22 is separated from the lower shear box 4. At this time, the experimenter can take out the experimental soil for replacement and conduct the next experiment, which improves the feeding efficiency of the experimenter when using the device, and thus improves the work efficiency of the experimenter.

[0033] Example 2 differs from Example 1 in that:

[0034] like Figure 1As shown, the front side of the discharge chamber 101 has two cabinet doors 14 that are symmetrically hinged to the left and right; the upper side of the experimental table 1 is provided with a guide platform 16 located between the lower shear box 4 and the fixed seat 9, and the upper side of the guide platform 16 is provided with a sliding groove for the upper shear box 5 to slide left and right; the front sides of the upper shear box 5 and the lower shear box 4 are symmetrically provided with transparent protective plates 13, and the transparent protective plates 13 on the upper shear box 5 and the lower shear box 4 can cooperate to form an observation window that can observe the internal conditions of the upper shear box 5 and the lower detection box.

[0035] In the above embodiment, the observation window formed by the two transparent protective plates 13 allows for direct observation of the deformation and failure process inside the soil sample, providing researchers with abundant visual information. At the same time, the cabinet door 14 can close the discharge chamber 101, thereby protecting the inside of the discharge chamber 101 and improving the safety of the device. The guide platform 16 further ensures the stability of the upper shear box 5 when sliding left and right, preventing the upper shear box 5 from deviating when sliding left and right, and ensuring the reliability of the device during use.

[0036] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A direct shear test apparatus for studying the characteristics of rock-soil interface interaction, comprising an experimental platform (1), wherein a lower shear box (4) is provided on the upper side of the experimental platform (1), and an upper shear box (5) is slidably connected to the upper side of the lower shear box (4), characterized in that: The upper side of the experimental platform (1) is provided with a horizontal shearing component for pulling the upper shear box (5) to slide horizontally left and right, and a normal shearing component for applying normal shearing force to the upper shear box (5) and the lower shear box (4). The front side of the experimental platform (1) is provided with a discharge cavity (101). The discharge cavity (101) is provided with a conveying component for feeding and discharging materials. The horizontal shearing component and the normal shearing component are also provided with a detection component for detecting experimental data.

2. The direct shear test apparatus for studying the characteristics of rock-soil interface interaction according to claim 1, characterized in that: The horizontal shearing assembly includes a fixed seat (9) set on the upper side of the experimental table (1), the fixed seat (9) is located on one side of the lower shearing box (4), the upper side of the fixed seat (9) is provided with a horizontal telescopic motor (10), and the side of the upper shearing box (5) is provided with a pull block (11) connected to the output shaft of the horizontal telescopic motor (10).

3. The direct shear test apparatus for studying the characteristics of rock-soil interface interaction according to claim 2, characterized in that: The experimental platform (1) has a guide platform (16) located between the lower shear box (4) and the fixed seat (9) on its upper side. The guide platform (16) has a groove on its upper side that allows the upper shear box (5) to slide left and right.

4. The direct shear test apparatus for studying the characteristics of rock-soil interface interaction according to claim 1, characterized in that: The normal shearing assembly includes four fixed columns (2) arranged in a rectangular array on the upper side of the experimental table (1). A top plate (3) is provided on the upper side of the four fixed columns (2). A translation plate (7) is slidably connected to the upper side of the top plate (3). A normal telescopic motor (8) is provided on the upper side of the translation plate (7). A connecting column (6) is provided at each of the four corners of the upper side of the upper shearing box (5) and connected to the lower side of the translation plate (7). A pressure plate (15) is slidably connected to the upper shearing box (5). The output shaft of the normal telescopic motor (8) passes through the translation plate (7) and is fixedly connected to the upper side of the pressure plate (15).

5. The direct shear test apparatus for studying the characteristics of rock-soil interface interaction according to claim 1, characterized in that: The conveying assembly includes a hydraulic lift (17) disposed in the discharge chamber (101), and a material box (22) is disposed on the output shaft of the hydraulic lift (17). The material box (22) can be inserted into the lower shear box (4) under the push of the hydraulic lift (17).

6. The direct shear test apparatus for studying the characteristics of rock-soil interface interaction according to claim 1, characterized in that: The front side of the discharge chamber (101) has two cabinet doors (14) that are symmetrically hinged.

7. A direct shear test apparatus for studying the characteristics of soil-rock interface interactions according to any one of claims 2 and 4, characterized in that: The detection components include a pressure sensor (18) and a normal displacement sensor (19) installed in the pressure plate (15), a tension sensor (20) and a horizontal displacement sensor (21) installed in the pull block (11). A display screen (12) is installed on the upper side of the experimental platform (1). The display screen (12) is electrically connected to the pressure plate (15) sensor, the normal displacement sensor (19), the tension sensor (20) and the horizontal displacement sensor (21).

8. The direct shear test apparatus for studying the interfacial characteristics of soil and rock according to claim 1, characterized in that: The upper shear box (5) and the lower shear box (4) are symmetrically provided with transparent protective plates (13) on their front sides. The transparent protective plates (13) on the upper shear box (5) and the lower shear box (4) can cooperate to form an observation window that allows observation of the internal conditions of the upper shear box (5) and the lower detection box.

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