Dry-wet cycle shear testing machine for coarse-grained soil

Abstract

The utility model discloses a coarse-grained soil dry-wet cycle shear testing machine which comprises a test bed, a sliding rail is arranged at the upper end of the test bed, a detachable lower shear box is connected to the sliding rail in a sliding mode, an upper shear ring is arranged at the upper end of the lower shear box, and a horizontal servo electric cylinder is installed at the end, located at the sliding rail, of the test bed. The horizontal servo electric cylinder is provided with a horizontal load sensor, the horizontal load sensor is provided with a push-pull shaft, and the test bench is provided with a displacement sensor at the other end of the slide rail; the upper end of the test bed is connected with a mounting frame, a vertical servo electric cylinder is downwards mounted on the mounting frame, a vertical load sensor is downwards arranged on the vertical servo electric cylinder, a rotating motor is arranged at the lower end of the vertical load sensor, and the test bed further comprises a pressing disc and a rotating disc which are detachably connected with the rotating motor. A plurality of hollow stirring rods with holes are arranged at the lower end of the rotating disc. When the coarse-grained soil is subjected to dry-wet cyclic shearing, a sample does not need to be taken out, and the sample can be saturated by directly stirring and injecting water, so that the experiment efficiency is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of geotechnical engineering experiments, in particular to a coarse-grained soil dry-wet cycle shear testing machine. Background Art

[0002] Coarse-grained soil is a high-quality dam-building material. In order to understand the mechanical properties of coarse-grained soil, it is necessary to use a shear tester to conduct shear tests on it and obtain the corresponding mechanical indicators. The significance of the study of dry-wet cyclic shear of coarse sand particles is to gain a deep understanding of the mechanical properties and behavioral characteristics of coarse sand particles under dry-wet alternating conditions. This kind of research helps to evaluate the performance of coarse sand particles in actual engineering, predict and respond to potential geological disaster risks, and provide important basis and reference for soil engineering design and research in related fields. By revealing the microscopic mechanism of coarse sand particles in the shear process, the stability and safety of soil engineering can be optimized, and the development and progress of related fields can be promoted.

[0003] However, there are many drawbacks in the current methods and means of conducting dry-wet cyclic shear tests on coarse-grained soil. The existing method is to soak the prepared coarse-grained soil in a container until it reaches a saturated state; then take it out and put it into a shear device for direct shear test; take it out after direct shearing, wait for it to dry, and then put it into the shear device for shearing, and repeat the saturation and drying to test the dry-wet cyclic shear mechanical properties of the coarse-grained soil. The sample is repeatedly taken out of the shear box, which is cumbersome to operate, and the soaking and drying are time-consuming, resulting in low experimental efficiency. Utility Model Content

[0004] The utility model aims to provide a coarse-grained soil dry-wet cycle shear testing machine. When the coarse-grained soil is dry-wet cycle sheared, the sample does not need to be taken out, and water can be directly stirred and injected to make it saturated with water. The operation is simple and the experimental efficiency is improved.

[0005] The above-mentioned technical purpose of the utility model is achieved through the following technical solutions: a coarse-grained soil dry-wet cycle shear testing machine, comprising a test bench, a slide rail is provided at the upper end of the test bench, a detachable lower shear box is slidably connected to the slide rail, the upper end of the lower shear box is open, a detachable upper shear ring is provided at the upper end of the lower shear box, the test bench is provided with limit members for limiting the movement of the upper shear ring at both ends of the sliding of the lower shear box, a horizontal servo electric cylinder is installed at one end of the slide rail of the test bench, a horizontal load sensor is provided on the power output shaft of the horizontal servo electric cylinder, a push-pull shaft is provided at one end of the horizontal load sensor facing the lower shear box, the free end of the push-pull shaft is detachably connected to the side wall of the lower shear box, and a displacement sensor matching the lower shear box is detachably connected to the end of the slide rail away from the horizontal servo electric cylinder of the test bench;

[0006] The upper end of the test bench is connected to a mounting frame, and the mounting frame is equipped with a vertical servo electric cylinder located directly above the upper shear ring. The lower end of the power output shaft of the vertical servo electric cylinder is provided with a vertical load sensor, and the lower end of the vertical load sensor is provided with a rotating motor. It also includes a pressure plate and a rotating plate that are detachably connected to the power output shaft at the lower end of the rotating motor, and the pressure plate and the rotating plate are both matched with the inner diameter of the upper shear ring. A plurality of hollow stirring rods are provided at the lower end of the rotating plate, and each central control stirring rod is provided with a plurality of water outlet holes distributed along its length. A water injection ring connected to each central control stirring rod is provided at the upper end of the rotating plate, and the water injection ring is connected to the outside with a water injection pipe.

[0007] By adopting the above technical scheme, a dry soil shear test is first carried out, the lower shear box and the upper shear ring are installed relative to each other, and the push-pull shaft is connected to the side wall of the lower shear box, the displacement sensor is installed so that it contacts the side wall of the lower shear box, and is zeroed, the coarse-grained soil sample is loaded into the lower shear box and the upper shear ring, the pressure plate is connected to the vertical threaded connecting shaft, the vertical servo electric cylinder is extended to make the pressure plate enter the upper shear ring to press the sample, and then the horizontal servo electric cylinder is started to extend slowly, pushing the lower shear box to slide and shear the sample, during which the values ​​of the vertical load sensor, the horizontal load sensor and the displacement sensor are recorded;

[0008] Then, a wet soil shearing experiment is carried out. After the dry soil shearing is completed, the horizontal servo electric cylinder is shortened to pull the lower shear box to reset, the vertical servo electric cylinder is shortened, and the pressure plate is replaced with a rotating plate. The vertical servo electric cylinder is extended again to insert the hollow stirring rod of the rotating plate into the sample. After the water injection pipe is connected to tap water, the rotating motor is started, and water is injected while stirring until the coarse-grained soil of the sample reaches a saturated state. The rotating plate is replaced with the pressure plate again, and the vertical servo electric cylinder is extended to make the pressure plate compact the sample. The horizontal servo electric cylinder is extended again to push the lower shear box to slide and shear the sample. During this period, the values ​​of the vertical load sensor, horizontal load sensor and displacement sensor are recorded;

[0009] After the shearing is completed, the vertical servo electric cylinder and the horizontal servo electric cylinder are shortened and reset, the displacement sensor is removed, the lower shear box and the upper shear ring are slid outward at the same time, they are removed, the samples therein are cleaned, and the experiment is completed.

[0010] The utility model is further configured as follows: a sliding block slidably connected to the sliding rail is provided at the lower end of the lower shear box.

[0011] The utility model is further configured as follows: the limit member includes an arched baffle frame close to the horizontal servo electric cylinder and a detachable baffle block close to the displacement sensor, the upper end of the arched baffle frame and the shape of the baffle block are both in contact with the outer wall of the upper shear ring, the test bench is provided with support bars on both sides of the slide rail, each support bar is provided with a clamping protrusion at the upper end, and the lower end of the baffle is provided with two clamping grooves which are respectively connected to the clamping protrusions in a one-to-one manner.

[0012] The utility model is further configured as follows: a horizontal threaded connection shaft is arranged on one side of the lower shear box facing the push-pull shaft, and a horizontal threaded connection sleeve threadedly connected to the horizontal threaded connection shaft is rotatably connected to the free end of the push-pull shaft.

[0013] The utility model is further configured as follows: the test bench is provided with a mounting platform matched with the displacement sensor at one end of the slide rail away from the horizontal servo electric cylinder, sliding strips are provided on both sides of the displacement sensor, and sliding slots slidably connected to the corresponding sliding strips are provided on both sides of the mounting platform, and each sliding slot is sealed at one end away from the horizontal servo electric cylinder.

[0014] The utility model is further configured as follows: a vertical threaded connection shaft is provided at the power output shaft at the lower end of the rotating motor; a vertical threaded connection sleeve is provided at the upper end of the pressure plate and the rotating plate and is threadedly connected to the vertical threaded connection shaft; an inner plug hole is provided horizontally through the vertical threaded connection shaft; an outer plug hole matching the inner plug hole is provided horizontally through each vertical threaded connection sleeve; and a pin is provided to match the inner plug hole and the outer plug hole.

[0015] In summary, the utility model has the following beneficial effects:

[0016] First, the shear tester of the utility model can perform dry-wet cycle shearing of coarse-grained soil. First, dry soil shearing is performed. After shearing, the dry coarse-grained soil can be quickly stirred and watered to quickly reach a saturated state. There is no need to soak it in water and wait for it to slowly become saturated with water. The test time can be effectively shortened. At the same time, there is no need to repeatedly take out the sample from the shear box. The operation is simpler and more convenient, which helps to improve the test efficiency.

[0017] Secondly, compared with taking out the sample and soaking it in water, the present invention can achieve true water-saturated shearing by stirring and injecting water in situ. Although the sample is immersed in water in the container and reaches a saturated state, when it is taken out of the container and placed in the shear box, the structural surface sample is no longer in a saturated environment, and true water-saturated shearing cannot be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0019] Figure 2 Mainly used to demonstrate the connection between the limiter and displacement sensor and the mounting platform;

[0020] Figure 3 Used to show the structure of the lower shear box, upper shear ring and stopper;

[0021] Figure 4 Used to demonstrate the connection between the rotating motor and the pressure plate.

[0022] In the figure: 1. test bench; 11. slide rail; 12. support bar; 13. clamping cam; 14. mounting table; 15. sliding clamping slot; 16. mounting frame; 2. lower shear box; 21. slider; 22. horizontal threaded connecting shaft; 3. upper shear ring; 41. arched retaining frame; 42. block; 43. clamping slot; 5. horizontal servo electric cylinder; 51. horizontal load sensor; 52. push-pull shaft; 53. horizontal threaded connecting sleeve; 6. displacement sensor; 61. sliding clamping strip; 7. vertical servo electric cylinder; 71. vertical load sensor; 72. rotating motor; 73. vertical threaded connecting shaft; 74. inner plug hole; 8. pressure plate; 81. vertical threaded connecting sleeve; 82. outer plug hole; 83. latch; 9. rotating disk; 91. hollow stirring rod; 92. water outlet; 93. water injection ring; 94. water injection pipe. DETAILED DESCRIPTION

[0023] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0024] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "back", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0025] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Example, see Figure 1-4 A coarse-grained soil dry-wet cycle shear testing machine comprises a test bench 1, a slide rail 11 is arranged at the upper end of the test bench 1, a detachable lower shear box 2 is slidably connected to the slide rail 11, a slider 21 slidably connected to the slide rail 11 is arranged at the lower end of the lower shear box 2, the upper end of the lower shear box 2 is opened, a detachable upper shear ring 3 is arranged at the upper end of the lower shear box 2, a group of limit members for limiting the movement of the upper shear ring 3 are arranged at both ends of the sliding of the lower shear box 2 of the test bench 1, and the limit members do not affect the sliding of the lower shear box 2. The limiting member includes an arched baffle 41 close to the horizontal servo electric cylinder 5 and a detachable baffle 42 close to the displacement sensor 6. The upper end of the arched baffle 41 and the shape of the baffle 42 are both in contact with the outer wall of the upper shear ring 3. The test bench 1 is provided with a support bar 12 on both sides of the slide rail 11. A protrusion 13 is provided at the upper end of each support bar 12. Two grooves 43 corresponding to the protrusions 13 are provided at the lower end of the baffle 42. The protrusion 13 is connected to the groove 43, so that the baffle 42 is connected to the support bar 12.

[0028] A horizontal servo electric cylinder 5 is installed at one end of the slide rail 11 of the test bench 1. The power output shaft of the horizontal servo electric cylinder 5 is provided with a horizontal load sensor 51. A push-pull shaft 52 is provided at one end of the horizontal load sensor 51 facing the lower shear box 2. A horizontal threaded connecting shaft 22 is provided on the side of the lower shear box 2 facing the push-pull shaft 52. The free end of the push-pull shaft 52 is rotatably connected to a horizontal threaded connecting sleeve 53 threadedly connected to the horizontal threaded connecting shaft 22. The horizontal servo electric cylinder 5 is connected to the lower shear box 2 through the connection between the horizontal threaded connecting sleeve 53 and the horizontal threaded connecting shaft 22. The test bench 1 is provided with a mounting platform 14 at the end of the slide rail 11 away from the horizontal servo electric cylinder 5. The mounting platform 14 is slidably connected with a detachable displacement sensor 6. Both sides of the displacement sensor 6 are provided with a sliding card strip 61 arranged along its length direction. Both sides of the mounting platform 14 are provided with a sliding card slot 15 slidably connected to the corresponding sliding card strip 61. The end of each sliding card slot 15 away from the horizontal servo electric cylinder 5 is sealed, so that the displacement sensor 6 can only be slid out from the end close to the slide rail 11.

[0029] The upper end of the test bench 1 is connected to an inverted U-shaped mounting frame 16, and the mounting frame 16 is installed with a vertical servo electric cylinder 7 located directly above the upper shear ring 3. The lower end of the power output shaft of the vertical servo electric cylinder 7 is provided with a vertical load sensor 71, and the lower end of the vertical load sensor 71 is provided with a rotating motor 72. It also includes a pressure plate 8 and a rotating plate 9, both of which are detachably connected to the power output shaft at the lower end of the rotating motor 72. The power output shaft at the lower end of the rotating motor 72 is provided with a vertical threaded connection shaft 73. The upper ends of the pressure plate 8 and the rotating plate 9 are both provided with a vertical threaded connection sleeve 81 threadedly connected to the vertical threaded connection shaft 73. An inner plug hole 74 is provided horizontally through the vertical threaded connection shaft 73, and an outer plug hole 82 matching with the inner plug hole 74 is provided horizontally through each vertical threaded connection sleeve 81. The inner plug hole 74 and the outer plug hole 82 are matched and connected with a latch 83. After connection, the vertical threaded connection shaft 73 can no longer rotate relative to the vertical threaded connection sleeve 81. The pressure plate 8 and the rotating plate 9 are matched with the inner diameter of the upper shear ring 3. Three hollow stirring rods 91 are arranged at the lower end of the rotating plate 9. Each central control stirring rod is provided with a plurality of water outlet holes 92 distributed along its length direction. A water injection ring 93 connected to each central control stirring rod is arranged at the upper end of the rotating plate 9. The water injection ring 93 is connected to the outside with a water injection pipe 94, and the water injection pipe 94 is used to connect tap water.

[0030] Usage: First, a dry soil shear test is carried out. The lower shear box 2 and the upper shear ring 3 are installed relative to each other, and the push-pull shaft 52 is connected to the side wall of the lower shear box 2. The displacement sensor 6 is installed so that it contacts the side wall of the lower shear box 2 and is adjusted to zero. The coarse-grained soil sample is loaded into the lower shear box 2 and the upper shear ring 3. The pressure plate 8 is connected to the vertical threaded connecting shaft 73. The vertical servo electric cylinder 7 is extended so that the pressure plate 8 enters the upper shear ring 3 to press the sample. Then, the horizontal servo electric cylinder 5 is started to extend slowly, and the lower shear box 2 is pushed to slide and shear the sample. During this period, the values ​​of the vertical load sensor 71, the horizontal load sensor 51 and the displacement sensor 6 are recorded.

[0031] Then, a wet soil shearing experiment is carried out. After the dry soil shearing is completed, the horizontal servo electric cylinder 5 is shortened to pull the lower shear box 2 to reset, the vertical servo electric cylinder 7 is shortened, and the pressure plate 8 is replaced with a rotating disk 9. The vertical servo electric cylinder 7 is extended again to insert the hollow stirring rod 91 of the rotating disk 9 into the sample. After the water injection pipe 94 is connected to tap water, the rotating motor 72 is started, and water is injected while stirring until the coarse-grained soil of the sample reaches a saturated state. The rotating disk 9 is replaced with the pressure plate 8 again, and the vertical servo electric cylinder 7 is extended to make the pressure plate 8 compact the sample. The horizontal servo electric cylinder 5 is extended again to push the lower shear box 2 to slide and shear the sample. During this period, the values ​​of the vertical load sensor 71, the horizontal load sensor 51 and the displacement sensor 6 are recorded;

[0032] After the shearing is completed, the vertical servo electric cylinder 7 and the horizontal servo electric cylinder 5 are shortened and reset, the displacement sensor 6 is removed, the block 42 is removed, and the lower shear box 2 and the upper shear ring 3 can be slid outward at the same time, removed, and the samples therein are cleaned to complete the experiment.

[0033] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A coarse-grained soil dry-wet cycle shear tester, comprising a test bench (1), characterized in that: The upper end of the test bench (1) is provided with a slide rail (11), and the slide rail (11) is slidably connected with a detachable lower shear box (2). The upper end of the lower shear box (2) is open, and the upper end of the lower shear box (2) is provided with a detachable upper shear ring (3). The test bench (1) is provided with limit members for limiting the movement of the upper shear ring (3) at both ends of the sliding of the lower shear box (2). The test bench (1) is installed with a horizontal servo electric cylinder (5) at one end of the slide rail (11). , the power output shaft of the horizontal servo electric cylinder (5) is provided with a horizontal load sensor (51), one end of the horizontal load sensor (51) facing the lower shear box (2) is provided with a push-pull shaft (52), the free end of the push-pull shaft (52) is detachably connected to the side wall of the lower shear box (2), and the test bench (1) is detachably connected to a displacement sensor (6) matched with the lower shear box (2) at one end of the slide rail (11) away from the horizontal servo electric cylinder (5); The upper end of the test bench (1) is connected to a mounting frame (16), and the mounting frame (16) is equipped with a vertical servo electric cylinder (7) located directly above the upper shear ring (3). The lower end of the power output shaft of the vertical servo electric cylinder (7) is provided with a vertical load sensor (71), and the lower end of the vertical load sensor (71) is provided with a rotating motor (72). It also includes a pressure plate (8) and a rotating plate (9) that are detachably connected to the power output shaft at the lower end of the rotating motor (72). The pressure plate (8) and the rotating plate (9) are both matched with the inner diameter of the upper shear ring (3). The lower end of the rotating plate (9) is provided with a plurality of hollow stirring rods (91), and each central control stirring rod is provided with a plurality of water outlet holes (92) distributed along its length direction. The upper end of the rotating plate (9) is provided with a water injection ring (93) connected to each central control stirring rod, and the water injection ring (93) is connected to the outside with a water injection pipe (94).

2. A coarse-grained soil dry-wet cycle shear testing machine according to claim 1, characterized in that: A sliding block (21) slidably connected to the sliding rail (11) is provided at the lower end of the lower shear box (2).

3. The coarse-grained soil dry-wet cycle shear testing machine according to claim 1, characterized in that: The limiting member comprises an arched baffle (41) close to the horizontal servo electric cylinder (5) and a detachable baffle (42) close to the displacement sensor (6); the upper end of the arched baffle (41) and the shape of the baffle (42) are both in contact with the outer wall of the upper shear ring (3); the test bench (1) is provided with support bars (12) on both sides of the slide rail (11); the upper end of each support bar (12) is provided with a locking protrusion (13); and the lower end of the baffle (42) is provided with two locking grooves (43) respectively connected to the locking protrusions (13) in a one-to-one correspondence.

4. The coarse-grained soil dry-wet cycle shear testing machine according to claim 1, characterized in that: A horizontal threaded connection shaft (22) is provided on one side of the lower shear box (2) facing the push-pull shaft (52), and a horizontal threaded connection sleeve (53) threadedly connected to the horizontal threaded connection shaft (22) is rotatably connected to the free end of the push-pull shaft (52).

5. The coarse-grained soil dry-wet cycle shear testing machine according to claim 1, characterized in that: The test bench (1) is provided with a mounting platform (14) matched with the displacement sensor (6) at one end of the slide rail (11) away from the horizontal servo electric cylinder (5), sliding clips (61) are provided on both sides of the displacement sensor (6), and sliding slots (15) slidably connected to the corresponding sliding clips (61) are provided on both sides of the mounting platform (14), and each sliding slot (15) is sealed at one end away from the horizontal servo electric cylinder (5).

6. The coarse-grained soil dry-wet cycle shear testing machine according to claim 1, characterized in that: The power output shaft at the lower end of the rotating motor (72) is provided with a vertical threaded connection shaft (73), and the upper ends of the pressure plate (8) and the rotating plate (9) are provided with vertical threaded connection sleeves (81) threadedly connected to the vertical threaded connection shaft (73). An inner plug hole (74) is horizontally passed through the vertical threaded connection shaft (73), and an outer plug hole (82) matching with the inner plug hole (74) is horizontally passed through each vertical threaded connection sleeve (81), and the inner plug hole (74) and the outer plug hole (82) are matched and connected with a latch (83).

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