Testing device for measuring shear viscosity of sandy soil in lateral confinement stress state

Abstract

The invention belongs to the technical field of geotechnical engineering test devices, and particularly relates to a test device for measuring shear viscosity of sandy soil in a lateral confinement stress state. The soil sample lateral confinement rotating mechanism comprises a rotating cylinder and a constraining frame, and the rotating cylinder is used for laterally constraining a soil sample and rotating along with the soil sample in an experimental test; the torque loading mechanism is arranged above the soil sample lateral confinement rotating mechanism and is used for applying torsion to the soil sample in the rotating cylinder and measuring the torque at the same time; the lifting mechanism is arranged on the rack and is used for adjusting the height of the torque loading mechanism; the vertical loading mechanism is arranged on the rack, is positioned below the soil sample lateral confinement rotating mechanism, and is used for applying vertical pressure to the soil sample in the rotating cylinder and measuring the pressure at the same time. According to the invention, the complex stress state of the sand foundation in the actual engineering can be simulated, and the test precision is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering test devices, and in particular relates to a test device for measuring the shear viscosity of sand under a confined stress state. Background Art

[0002] The shear viscosity of sand varies significantly with dry density and stress state. Accurately measuring its shear viscosity under different density and stress conditions is crucial to ensuring the long-term safety of sand foundation projects.

[0003] Existing rotational shear rheometers are only suitable for thin-layer fluids or pastes. They cannot control pressure and density when measuring the shear viscosity of sand. After the sample is subjected to vertical pressure, there is no lateral constraint. If only lateral constraints are added to the sample, the resistance torque caused by friction between the lateral constraint and the sample contact surface will cause serious tangential interference to the sample rotation.

[0004] Therefore, it is necessary to provide a test device for measuring the shear viscosity of sand under the lateral confining stress state to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a test device for measuring the shear viscosity of sand under lateral confined stress state, so as to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides a test device for measuring the shear viscosity of sand under confined stress state, comprising: a frame;

[0007] A soil sample lateral restraint rotation mechanism, comprising a rotating cylinder and a restraint frame, wherein the restraint frame is disposed on the frame, the rotating cylinder being rotatably connected to the restraint frame, the rotating cylinder being used to laterally restrain the soil sample and rotating with the soil sample during experimental testing;

[0008] a torque loading mechanism, the torque loading mechanism being arranged above the soil sample side limiting rotation mechanism and being used for applying a torsional force to the soil sample in the rotating cylinder and measuring the torque at the same time;

[0009] a lifting mechanism, the lifting mechanism being disposed on the frame and being used to adjust the height of the torque loading mechanism;

[0010] A vertical loading mechanism is provided on the frame and is located below the soil sample side limit rotation mechanism. The vertical loading mechanism is used to apply vertical pressure to the soil sample in the rotating cylinder and measure the pressure at the same time.

[0011] Optimized, the constraint frame includes a fixed seat, the cross-section of the fixed seat is a circular ring structure, the top of the frame is horizontally fixedly connected to a platform, the fixed seat is fastened to the middle of the platform by bolts, the rotating cylinder is slidably arranged in the middle of the platform, and a plurality of constraint rods are arranged on the fixed seat at equal intervals along the circumference of the rotating cylinder, the tops of the plurality of constraint rods are commonly connected to an annular plate, and the outer wall of the rotating cylinder is in sliding contact with the constraint rods.

[0012] Optimally, the cross section of the restraining rod is circular, and grease is applied between the restraining rod and the rotating cylinder.

[0013] Optimally, the cross-section of the constraint rod is rectangular, and a plurality of balls 2 are embedded on the side of the constraint rod close to the rotating cylinder. The balls 2 are arranged at equal intervals along the extension direction of the constraint rod, and the balls 2 are in rolling contact with the outer wall of the rotating cylinder.

[0014] Optimally, the rotating cylinder includes a plurality of rigid rings, the plurality of rigid rings are coaxially stacked, and two adjacent rigid rings are slidingly arranged, and the rigid ring located at the bottom is slidingly matched with the fixing seat.

[0015] Optimally, both the upper and lower end faces of the rigid ring are provided with an annular groove 1, the cross section of the annular groove 1 is semicircular, and a plurality of balls 2 are provided between the annular grooves on two adjacent rigid rings.

[0016] Optimally, a second annular groove is provided at the top of the fixing seat, the second annular groove is arranged corresponding to the first annular groove, and a plurality of first balls are arranged between the second annular groove and the first annular groove.

[0017] Optimized, the lifting mechanism includes vertical plates fixedly connected to both ends of the platform, a two-way threaded rod is rotatably connected between the top ends of the two vertical plates, one end of the two-way threaded rod is connected to a crank, two threaded blocks are threadedly connected to the two-way threaded rod, a slide is provided below the two-way threaded rod, the torque loading mechanism is installed in the middle of the slide, the two threaded blocks are symmetrically arranged on both sides of the torque loading mechanism, the top of the slide is fixedly connected to two hinged seats, one end of the pull rod is hinged to any of the hinged seats, and the other end of the pull rod is hinged to the threaded block.

[0018] Optimally, the torque loading mechanism includes a reduction motor, an output shaft of the reduction motor is fixedly connected to an upper pressure plate, and a torque sensor is provided on the output shaft of the reduction motor.

[0019] Optimized, the middle part of the platform is slidably connected to a push rod, the top end of the push rod is coaxially connected to a lower pressure plate, the lower pressure plate is coaxially arranged with the rotating cylinder, the bottom end of the push rod is connected to a pressure sensor, the bottom end of the pressure sensor is connected to a support plate, the vertical loading mechanism includes a loading device, the loading device is installed in the frame, and the output shaft of the loading device is in contact with the support plate.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] The present invention provides a test device for measuring the shear viscosity of sand under the lateral confinement stress state. When in use, the torque loading mechanism can accurately apply and measure the torque. Combined with the stable rotation of the rotating cylinder, dynamic regulation of the shear rate and shear stress is achieved, the friction between the sand and the rotating cylinder is minimized, and the control accuracy of the shear state is improved; the combined design of the vertical loading mechanism and the rotating cylinder can simulate the complex stress state of the sand foundation in actual engineering; by optimizing the rotating cylinder structure and the lateral confinement constraint method, coarse-grained materials such as gravel sand can be directly tested, expanding the scope of application of the rotational shear rheometer; by accurately measuring the shear viscosity of sand under complex stress states, key mechanical parameters can be provided for foundation treatment of filling projects and foundation projects.

[0022] The present invention solves the core pain points of traditional rotational shear rheometers in sand and soil testing, significantly improves the test accuracy and engineering relevance, and provides an efficient and reliable tool for studying the rheological properties of sand and soil in the field of geotechnical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work.

[0024] Figure 1 This is a schematic diagram of the overall structure of a test device for measuring the shear viscosity of sand under confined stress state proposed by the present invention;

[0025] Figure 2 for Figure 1 A partial enlarged view of point A in the middle;

[0026] Figure 3 A top view of the torque loading mechanism of the present invention;

[0027] Figure 4 is a top view of the rigid ring of the present invention;

[0028] Among them: 1. Frame; 2. Loading device; 3. Support plate; 4. Pressure sensor; 5. Push rod; 6. Slide rod; 7. Spring; 8. Slide plate; 9. Articulated seat; 10. Vertical plate; 11. Crank handle; 12. Bidirectional threaded rod; 13. Threaded block; 14. Pull rod; 15. Reducer motor; 16. Platform; 17. Fixed seat; 18. Ball 1; 19. Rigid ring; 20. Ring plate; 21. Torque sensor; 22. Upper pressure plate; 23. Constraint rod; 24. Ball 2; 25. Lower pressure plate. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] The technical terms in the embodiments are explained below:

[0032] Damping grease G1023 introduction:

[0033] Damping Grease G1023, also known as Molykote G-1023, is a high-performance damping grease from the MOLYKOTE brand, a subsidiary of DuPont (now distributed by Super Run Trading (Shanghai) Co., Ltd.). It is widely used in industrial equipment, automotive components, and precision machinery systems. The following is a detailed introduction from four aspects: product characteristics, technical parameters, application scenarios, and usage precautions:

[0034] Product Features

[0035] Ingredients and structure:

[0036] Base oil: Synthetic base oil is used, which has excellent thermal stability and oxidation stability and can maintain lubrication performance at high temperatures.

[0037] Thickener: Lithium-based thickener, which gives the grease good adhesion and mechanical stability, and prevents the grease from softening or losing under shear force.

[0038] Additives: Contains anti-wear, anti-corrosion and anti-rust additives to enhance the protection of metal surfaces and extend the life of equipment.

[0039] Physical properties:

[0040] Appearance: White paste, uniform texture, no stratification or precipitation.

[0041] Needle penetration: 280mm / 10 (reflects the consistency, the smaller the value, the thicker it is), ensuring that the grease forms an oil film of sufficient thickness on the friction surface.

[0042] Working temperature: -45℃ to 120℃, covering extremely cold to high temperature environments, with strong adaptability.

[0043] Oil separation amount: 2.4% (24 hours, 100°C), indicating stable lubrication performance at high temperatures and low oil separation rate.

[0044] Damping and lubrication performance

[0045] High resistance characteristics: The high viscosity design achieves a damping effect, making the moving parts (such as knobs and gears) operate smoothly and reducing vibration and noise.

[0046] Low friction coefficient: While providing damping, it reduces the friction resistance between moving parts and improves energy efficiency.

[0047] Material compatibility: Compatible with most metals, plastics and rubber materials, suitable for complex working conditions.

[0048] Application Scenario

[0049] optical instruments

[0050] Used in focus knobs of microscopes, telescopes, and cameras, it provides precise damping to ensure smooth and lag-free operation.

[0051] Automotive and Industrial Equipment

[0052] Automotive parts: door hinges, sunroof rails, seat adjustment mechanisms, reducing noise and extending service life.

[0053] Industrial equipment: bearings, gearboxes, chain drive systems, maintaining long-term lubrication under heavy loads or high temperatures.

[0054] Electronic appliances

[0055] Gear sets of printers and copiers reduce operating noise and improve equipment stability.

[0056] Potentiometer and tuner knob enable fine damping adjustment and improve operating feel.

[0057] Precision Machinery

[0058] The fine-tuning mechanism of laboratory instruments and medical equipment ensures precise and controllable movements.

[0059] Reference Figures 1 to 4 As shown, the present invention provides a test device for measuring the shear viscosity of sand under confined stress state, comprising:

[0060] Rack 1;

[0061] The soil sample lateral limit rotation mechanism includes a rotating cylinder and a constraint frame. The constraint frame is arranged on the frame 1. The rotating cylinder is rotatably connected to the constraint frame. The rotating cylinder is used to laterally constrain the soil sample and rotates with the soil sample during the experimental test.

[0062] The torque loading mechanism is arranged above the soil sample side limit rotation mechanism and is used to apply torque to the soil sample in the rotating cylinder and measure the torque at the same time;

[0063] A lifting mechanism is provided on the frame 1 and is used to adjust the height of the torque loading mechanism;

[0064] The vertical loading mechanism is provided on the frame 1 and is located below the soil sample side limit rotation mechanism. The vertical loading mechanism is used to apply vertical pressure to the soil sample in the rotating cylinder and measure the pressure at the same time.

[0065] The torque loading mechanism of the present invention can accurately apply and measure torque. Combined with the stable rotation of the rotating drum, it realizes dynamic regulation of shear rate and shear stress, and improves the control accuracy of the shear state. The combined design of the vertical loading mechanism and the rotating drum can simulate the complex stress state of sand foundation in actual engineering. By optimizing the rotating drum structure and the lateral constraint method, coarse-grained materials such as gravel-containing sand can be directly tested, expanding the scope of application of the rotational shear rheometer. By accurately measuring the shear viscosity of sand under complex stress states, key mechanical parameters can be provided for foundation treatment of filling projects and foundation projects.

[0066] The present invention solves the core pain points of traditional rotational shear rheometers in sand and soil testing, significantly improves the test accuracy and engineering relevance, and provides an efficient and reliable tool for studying the rheological properties of sand and soil in the field of geotechnical engineering.

[0067] Furthermore, the restraint frame includes a fixed seat 17, the cross-section of the fixed seat 17 is a circular ring structure, the top of the frame 1 is horizontally fixedly connected to the platform 16, the fixed seat 17 is fastened to the middle of the platform 16 by bolts, the rotating cylinder is slidingly set in the middle of the platform 16, and multiple restraint rods 23 are arranged on the fixed seat 17 at equal intervals along the circumference of the rotating cylinder. The tops of the multiple restraint rods 23 are commonly connected to the annular plate 20, and the outer wall of the rotating cylinder is in sliding contact with the restraint rods 23.

[0068] The constraint frame design achieves high-precision guidance and low-friction constraint of the rotating cylinder through an annular constraint system, sliding contact mechanism and modular structure, significantly improving the accuracy, stability and engineering applicability of shear viscosity testing under the lateral confined stress state of sand, and providing a reliable experimental platform for studying the rheological behavior of sand under complex stress paths.

[0069] Furthermore, the cross section of the restraining rod 23 is circular, and grease is applied between the restraining rod 23 and the rotating cylinder.

[0070] In this embodiment, the grease is damping grease G1023, which reduces the friction between the restraining rod 23 and the rotating cylinder.

[0071] The circular cross-section design of the restraint rod 23 and the grease application technology avoid the shear rate fluctuations caused by friction interference in traditional equipment by optimizing contact mechanical behavior and reducing friction loss, ensuring the uniformity of the shear strain of the soil sample, and significantly improving the test accuracy, stability and durability of the test device, providing key technical guarantees for the accurate measurement of shear viscosity under the lateral confining stress state of sand.

[0072] Furthermore, the cross section of the restraining rod 23 is rectangular, and a plurality of second balls 24 are embedded on the side of the restraining rod 23 close to the rotating cylinder. The second balls 24 are arranged at equal intervals along the extension direction of the restraining rod 23, and the second balls 24 are in rolling contact with the outer wall of the rotating cylinder.

[0073] The rectangular cross-section facilitates the creation of ball mounting grooves within the rod body, enabling embedded placement of the balls while maintaining the compactness of the rod's outer contour. This design optimizes the structural layout within limited rack space and facilitates the circumferential arrangement of multiple rods at equal spacing.

[0074] The rolling contact between the ball and the rotating cylinder converts the traditional sliding friction into rolling friction, reducing the friction coefficient. Through the synergistic effect of rigid constraint and low-friction rotation, the shear viscosity test under the sand confined stress state is achieved, minimizing the friction between the sand and the inner wall of the rigid ring 19, further improving the accuracy of the shear viscosity test under the sand confined stress state.

[0075] Furthermore, the rotating drum includes a plurality of rigid rings 19 , which are coaxially stacked and arranged, and two adjacent rigid rings 19 are slidably arranged, and the rigid ring 19 at the bottom is slidably matched with the fixing seat 17 .

[0076] The coaxial stacking design of multiple rigid rings 19 further reduces the friction between the rotating drum as a whole and the sand.

[0077] Furthermore, an annular groove 1 is formed on both the upper and lower end surfaces of the rigid ring 19 . The cross section of the annular groove 1 is semicircular. A plurality of second balls 24 are provided between the annular grooves on two adjacent rigid rings 19 .

[0078] Furthermore, a second annular groove is provided at the top of the fixing seat 17 , the second annular groove is provided corresponding to the first annular groove, and a plurality of balls 18 are provided between the second annular groove and the first annular groove.

[0079] Annular groove 1 on the end face of rigid ring 19 forms a rolling contact pair with ball 24, converting traditional planar sliding friction into pure rolling friction, reducing the friction coefficient. Furthermore, the semicircular cross-section of the groove radially limits the ball, preventing it from falling or shifting during testing and ensuring long-term operational stability.

[0080] The bottom rigid ring and fixed seat 17 form a second-level rolling support through annular groove 2 and ball 18, reducing sliding friction between the rotating cylinder and the base. This design enables the rotating cylinder to achieve "zero-friction rotation" under vertical pressure and torque. The torque measurement directly reflects the shear resistance of the soil sample, eliminating friction interference within the equipment itself.

[0081] Furthermore, the lifting mechanism includes a vertical plate 10 fixedly connected to both ends of the platform 16, a bidirectional threaded rod 12 is rotatably connected between the top ends of the two vertical plates 10, one end of the bidirectional threaded rod 12 is connected to a crank 11, two threaded blocks 13 are threadedly connected to the bidirectional threaded rod 12, a slide 8 is provided below the bidirectional threaded rod 12, the torque loading mechanism is installed in the middle of the slide 8, the two threaded blocks 13 are symmetrically arranged on both sides of the torque loading mechanism, the top of the slide 8 is fixedly connected to two articulated seats 9, one end of a pull rod 14 is hinged on any articulated seat 9, and the other end of the pull rod 14 is hinged on the threaded block 13.

[0082] In this embodiment, slide bars 6 are vertically connected to both ends of the platform 16. The two slide bars 6 are symmetrically arranged on both sides of the torque loading mechanism. The top ends of the two slide bars 6 pass through the slide bar 8. A linear bearing is provided on the slide bar 8. The slide bar 6 is slidingly connected to the slide bar 8 through the linear bearing. The sliding sleeve on the slide bar 6 is provided with a spring 7. The spring 7 is elastically connected to the slide bar 8. When the crank 11 is shaken, the crank 11 drives the bidirectional threaded rod 12 to rotate, and the two threaded blocks 13 threadedly connected to the bidirectional threaded rod 12 approach each other. During this process, the thread block 13 pushes the slide bar 8 through the pull rod 14 to compress the spring 7 and move along the slide bar 6, thereby driving the torque loading mechanism to move downward so that its output end contacts the soil sample, and then the shaking of the crank 11 is stopped.

[0083] Furthermore, the torque loading mechanism includes a reduction motor 15 , an output shaft of the reduction motor 15 is fixedly connected to an upper pressing plate 22 , and a torque sensor 21 is provided on the output shaft of the reduction motor 15 .

[0084] During the experimental test, the upper pressure plate 22 is pressed on the top of the soil sample, and the upper pressure plate 22 is driven to rotate by the reduction motor 15, thereby increasing the rotational torque for the soil sample. The torque data can be obtained through the provided torque sensor 21 and transmitted to the test terminal; in the experimental test, according to the experimental requirements, the crank 11 can also be continued to be rotated to provide torque to the soil sample while providing vertical loading.

[0085] Furthermore, the middle part of the platform 16 is slidably connected to a push rod 5, the top end of the push rod 5 is coaxially connected to a lower pressure plate 25, the lower pressure plate 25 is coaxially arranged with the rotating cylinder, the bottom end of the push rod 5 is connected to a pressure sensor 4, the bottom end of the pressure sensor 4 is connected to a support plate 3, the vertical loading mechanism includes a loading device 2, the loading device 2 is installed in the frame 1, and the output shaft of the loading device 2 is in contact with the support plate 3.

[0086] In this embodiment, the loading device 2 is a hydraulic rod; before the test, the lower pressure plate 25 extends into the bottom of the rotating cylinder and supports the soil sample, and the output end of the loading device 2 is extended to press on the support plate 3. As the output end of the loading device 2 continues to extend, vertical loading of the soil sample is achieved, and the detected data is transmitted to the test terminal through the set pressure sensor 4.

[0087] The test device provided by the present invention is used to measure the shear viscosity of sand under the lateral limit stress state. The working principle is as follows: when in use, the annular groove 2 on the fixed seat 17 is filled with ball 18, and then the first rigid ring 19 is stacked on the fixed seat 17, so that the ball 18 enters the annular groove 2 at the bottom of the rigid ring 19, and then the lower pressure plate 25 is placed in the rigid ring 19. The top rod 5 at the bottom of the lower pressure plate 25 passes through the hole on the platform 16 and is connected to the pressure sensor 4 and the support plate 3 in sequence, and then the annular groove 1 at the upper end of the first rigid ring 19 is filled with ball 18, and the second rigid ring 19 is stacked. The above operation is repeated as required to complete the stacking of the last rigid ring 19 to form a rotating Cylinder, put the soil sample into the rotating cylinder according to the experimental requirements, and then shake the crank 11 to rotate. The rotating crank 11 drives the bidirectional threaded rod 12 to rotate, and the two threaded blocks 13 threaded on the bidirectional threaded rod 12 approach each other. In this process, the threaded block 13 pushes the slide plate 8 through the pull rod 14 to compress the spring 7 and move along the slide rod 6, thereby driving the reduction motor 15 to move downward, so that the upper pressure plate 22 on the output end extends into the rotating cylinder and contacts the top of the soil sample, and then stops shaking the crank 11, and then starts the loading device 2. The output end of the loading device 2 presses the support plate 3 and the lower pressure plate 25 to continuously load the soil sample, and at the same time starts the reduction motor 15 to perform tests according to the experimental requirements.

[0088] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0089] The above are only preferred specific implementation methods of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in this application should be covered by the scope of protection of the present application.

Claims

1. A test device for measuring the shear viscosity of sand under confined stress state, characterized in that: include: Rack (1); A soil sample side-limited rotation mechanism, comprising a rotating cylinder and a restraining frame, wherein the restraining frame is arranged on the frame (1), the rotating cylinder is rotatably connected to the restraining frame, and the rotating cylinder is used to restrain the soil sample laterally and rotate with the soil sample during experimental testing; a torque loading mechanism, the torque loading mechanism being arranged above the soil sample side limiting rotation mechanism and being used for applying a torsional force to the soil sample in the rotating cylinder and measuring the torque at the same time; A lifting mechanism, the lifting mechanism being arranged on the frame (1) and being used for adjusting the height of the torque loading mechanism; A vertical loading mechanism is provided on the frame (1) and is located below the soil sample side limit rotation mechanism. The vertical loading mechanism is used to apply vertical pressure to the soil sample in the rotating cylinder and measure the pressure at the same time.

2. The test device for measuring shear viscosity of sand under confined stress state according to claim 1, characterized in that: The restraint frame includes a fixed seat (17), the cross section of the fixed seat (17) is a circular ring structure, the top of the frame (1) is horizontally fixedly connected to a platform (16), the fixed seat (17) is fastened to the middle of the platform (16) by bolts, the rotating cylinder is slidably arranged in the middle of the platform (16), a plurality of restraint rods (23) are arranged on the fixed seat (17) at equal intervals along the circumference of the rotating cylinder, the tops of the plurality of restraint rods (23) are commonly connected to an annular plate (20), and the outer wall of the rotating cylinder is in sliding contact with the restraint rods (23).

3. The test device for measuring shear viscosity of sand under confined stress state according to claim 2, characterized in that: The cross section of the restraining rod (23) is circular, and lubricating grease is applied between the restraining rod (23) and the rotating cylinder.

4. The test device for measuring shear viscosity of sand under confined stress state according to claim 2, characterized in that: The cross section of the restraining rod (23) is rectangular. A plurality of second balls (24) are embedded on one side of the restraining rod (23) close to the rotating cylinder. The second balls (24) are arranged at equal intervals along the extension direction of the restraining rod (23). The second balls (24) are in rolling contact with the outer wall of the rotating cylinder.

5. The test device for measuring shear viscosity of sand under confined stress state according to claim 2, characterized in that: The rotating cylinder comprises a plurality of rigid rings (19), the plurality of rigid rings (19) are coaxially stacked, two adjacent rigid rings (19) are slidably arranged, and the rigid ring (19) located at the bottom is slidably matched with the fixing seat (17).

6. The test device for measuring shear viscosity of sand under confined stress state according to claim 5, characterized in that: The upper and lower end surfaces of the rigid ring (19) are both provided with an annular groove 1, the cross section of the annular groove 1 is semicircular, and a plurality of balls 2 (24) are provided between the annular grooves on two adjacent rigid rings (19).

7. The test device for measuring shear viscosity of sand under confined stress state according to claim 6, characterized in that: The top of the fixing seat (17) is provided with an annular groove 2, the annular groove 2 is arranged corresponding to the annular groove 1, and a plurality of balls 1 (18) are arranged between the annular groove 2 and the annular groove 1.

8. The test device for measuring shear viscosity of sand under confined stress state according to claim 2, characterized in that: The lifting mechanism includes a vertical plate (10) fixedly connected to both ends of the platform (16), a bidirectional threaded rod (12) is rotatably connected between the top ends of the two vertical plates (10), one end of the bidirectional threaded rod (12) is connected to a crank (11), two threaded blocks (13) are threadedly connected to the bidirectional threaded rod (12), a slide (8) is provided below the bidirectional threaded rod (12), the torque loading mechanism is installed in the middle of the slide (8), the two threaded blocks (13) are symmetrically arranged on both sides of the torque loading mechanism, the top end of the slide (8) is fixedly connected to two hinged seats (9), one end of a pull rod (14) is hinged to any of the hinged seats (9), and the other end of the pull rod (14) is hinged to the threaded block (13).

9. The test device for measuring shear viscosity of sand under confined stress state according to claim 1, characterized in that: The torque loading mechanism comprises a reduction motor (15), the output shaft of the reduction motor (15) is fixedly connected to an upper pressing plate (22), and a torque sensor (21) is provided on the output shaft of the reduction motor (15).

10. The test device for measuring shear viscosity of sand under confined stress state according to claim 2, characterized in that: The middle part of the platform (16) is slidably connected to a push rod (5), the top end of the push rod (5) is coaxially connected to a lower pressure plate (25), the lower pressure plate (25) is coaxially arranged with the rotating cylinder, the bottom end of the push rod (5) is connected to a pressure sensor (4), the bottom end of the pressure sensor (4) is connected to a support plate (3), the vertical loading mechanism includes a loading device (2), the loading device (2) is installed in the frame (1), and the output shaft of the loading device (2) is in contact with the support plate (3).

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