A device and method for preparing a true triaxial specimen of fluid state remolded soil

Abstract

The present application relates to a device for preparing a true triaxial specimen of fluid-state remolded soil, comprising: a specimen preparation cylinder with openings at both its upper and lower ends. A plurality of first drainage holes are provided on the side wall of the specimen preparation cylinder. A filter cotton is wrapped around the outer wall of the specimen preparation cylinder. A drainage base flush with its bottom is embedded in the specimen preparation cylinder. A first permeable stone, a fluid-state remolded soil specimen, a second permeable stone, and a piston are successively arranged on the drainage base from bottom to top. The piston is slidably arranged in the specimen preparation cylinder. A limiting plate is provided at the upper end of the piston. A vertical rod and a weight tray are successively arranged on the upper end of the limiting plate from bottom to top. A first total drainage groove is provided on the drainage base, and a second total drainage groove is provided on the piston. The structure of the present application is simple, avoiding the disturbance to the specimen caused by cutting, simplifying the production process of the true triaxial remolded specimen, and effectively improving the research efficiency of the true triaxial test. The present application also provides a specimen preparation method for preparing a true triaxial specimen of fluid-state remolded soil using the specimen preparation device.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering, and particularly relates to a device and method for preparing a true triaxial specimen of fluidized remolded soil. Background Art

[0002] Commonly used methods for preparing remolded soil specimens mainly include compaction method, sedimentation method, freezing method, etc. These methods all have drawbacks to varying degrees while preparing specimens. During use, experts and scholars mainly improved these drawbacks from the sampling equipment.

[0003] Among them, for the preparation of true triaxial specimens, a Chinese invention patent with the publication number CN104089802B discloses a device and method for preparing true triaxial remolded specimens by vacuum preloading, and proposes a sampling device for quickly preparing multiple true triaxial remolded soil specimens with high water content. It improves the uniformity and accuracy of the specimen density, water content and saturation, but its sampling device has a complex structure, the sampling process is cumbersome, and it is necessary to use a wire saw to cut off the reserved layer of the specimen, and the cutting will cause disturbance to the specimen. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a device and method for preparing a true triaxial specimen of fluidized remolded soil, which has a simple structure, avoids the disturbance caused by cutting to the specimen, simplifies the production process of the true triaxial remolded specimen, and effectively improves the research efficiency of the true triaxial test.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a device for preparing a true triaxial specimen of fluidized remolded soil, comprising: a sampling cylinder with openings at both its upper and lower ends. A plurality of first drainage holes are provided on the side wall of the sampling cylinder. The outer wall of the sampling cylinder is wrapped with filter cotton. A drainage seat flush with the bottom of the sampling cylinder is embedded in the sampling cylinder. A first permeable stone, a fluidized remolded soil specimen, a second permeable stone and a piston are successively arranged on the drainage seat from bottom to top. The piston is slidably arranged in the sampling cylinder. A limiting plate is provided at the upper end of the piston. A vertical rod and a weight tray are successively arranged at the upper end of the limiting plate from bottom to top. The weight tray is used for placing weights. A first total drainage groove for drainage is provided on the drainage seat. A second total drainage groove for drainage is provided on the piston.

[0006] Preferably, a bottom plate is provided at the lower end of the sampling cylinder.

[0007] Preferably, a plurality of sampling cylinders are provided and arranged at intervals on the upper end of the bottom plate.

[0008] Preferably, the first main drainage groove includes a cross-shaped drainage groove A respectively arranged on the upper and lower end faces of the drainage seat. Four first sub-drainage grooves for communicating the upper and lower cross-shaped drainage grooves A are spaced on the peripheral side wall of the drainage seat. First rectangular drainage grooves communicating with the cross-shaped drainage groove A are respectively arranged on the upper and lower end faces of the drainage seat. A first circular drainage groove communicating with the cross-shaped drainage groove A is arranged inside the inner circle of the first rectangular drainage groove. A plurality of second drainage holes penetrating the upper and lower end faces of the drainage seat are arranged in the grooves of the cross-shaped drainage groove A, the first rectangular drainage groove and the first circular drainage groove.

[0009] Preferably, the second main drainage groove includes a cross-shaped drainage groove B respectively arranged on the upper and lower end faces of the piston. Four second sub-drainage grooves for communicating the upper and lower cross-shaped drainage grooves B are spaced on the peripheral side wall of the piston. Second rectangular drainage grooves communicating with the cross-shaped drainage groove B are respectively arranged on the upper and lower end faces of the piston. A second circular drainage groove communicating with the cross-shaped drainage groove B is arranged inside the inner circle of the second rectangular drainage groove. A plurality of third drainage holes penetrating the upper and lower end faces of the piston are arranged in the grooves of the cross-shaped drainage groove B, the second rectangular drainage groove and the second circular drainage groove.

[0010] Preferably, the cross-sectional area of the limiting plate is larger than the cross-sectional area of the piston.

[0011] The sample preparation method for making a true triaxial sample of fluid remolded soil by using the above sample preparation device includes the following steps:

[0012] Step 1: Prepare fluid remolded soil. Weigh a certain amount of remolded soil and mix it with water to prepare a fluid remolded soil slurry.

[0013] Step 2: Load the sample. Apply grease evenly inside the sample preparation cylinder, wrap filter cotton outside the sample preparation cylinder, install the drainage seat at the bottom of the sample preparation cylinder, place the first permeable stone and filter paper in sequence on the upper end of the drainage seat, pour the prepared fluid remolded soil slurry into the inside of the sample preparation cylinder, and place the filter paper, the second permeable stone and the piston in sequence on the top.

[0014] Step 3: Load. Place a certain weight of weights on the top of the weight pan and let it stand. The liquid inside the fluid remolded soil sample will be discharged through the first drainage holes of the sample preparation cylinder, the first main drainage groove of the drainage seat and the second drainage groove of the piston. The fluid remolded soil sample undergoes consolidation settlement. When the limiting plate contacts the top of the sample preparation cylinder, the preparation of the fluid remolded soil sample is completed.

[0015] Step 4: Remove the fluid remolded soil sample. Remove the weights and the piston in sequence, gently push the drainage seat below the fluid remolded soil sample, and push the fluid remolded soil sample out of the sample preparation cylinder.

[0016] The beneficial effects of the present application are as follows: 1. Multiple first drainage holes are provided on the outer wall of the sample preparation cylinder, and filter cotton is wrapped outside the sample preparation cylinder, which can effectively ensure that the liquid inside the sample drains out from the first drainage holes of the sample preparation cylinder and prevent the remolded soil from flowing out along with the drainage of the liquid;

[0017] 2. The present invention improves the drainage direction during the preparation process of the fluid remolded soil sample. By providing first drainage holes on the side wall of the sample preparation cylinder, a first main drainage groove on the drainage seat, and a second main drainage groove on the piston, the liquid inside the sample can be drained through both ends and the side wall of the sample, effectively ensuring the uniformity of the sample;

[0018] 3. By improving the structure of the sample preparation device, the present invention makes the operation process of the true triaxial sample simpler, facilitates the disassembly of the sample, and can effectively ensure the integrity of the prepared sample. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention;

[0020] Figure 2 is Figure 1 a top view;

[0021] Figure 3 is Figure 2 the A-A cross-sectional view of;

[0022] Figure 4 is a schematic structural diagram of the drainage seat;

[0023] Figure 5 is a schematic structural diagram of the piston;

[0024] Figure 6 is a schematic structural diagram of Embodiment 2 of the present invention.

[0025] Markings in the figure: 1. Base plate, 2. Sample preparation cylinder, 201. First drainage hole, 202. Water flow groove, 3. Piston, 301. Third drainage hole, 302. Cross-shaped drainage groove B, 303. Second sub-drainage groove, 304. Second rectangular drainage groove, 305. Second circular drainage groove, 4. Limiting plate, 5. First locking nut, 6. Vertical rod, 7. Weight pan, 8. Drainage seat, 801. Second drainage hole, 802. Cross-shaped drainage groove A, 803. First sub-drainage groove, 804. First rectangular drainage groove, 805. First circular drainage groove, 9. First permeable stone, 10. Fluid remolded soil sample, 11. Second permeable stone, 12. Second locking nut. Detailed Embodiments

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that in the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more; the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the 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 orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0027] Please refer to Figures 1-5 , the present invention provides a device for preparing a true triaxial specimen of fluid-state remolded soil, including: a sample preparation cylinder 2, which is open at both the upper and lower ends. A plurality of first drainage holes 201 are provided on the side wall of the sample preparation cylinder 2. A filter cotton is wrapped around the outer wall of the sample preparation cylinder 2. A drainage seat 8 flush with its bottom is embedded in the sample preparation cylinder 2. The drainage seat 8 can slide up and down along the inner wall of the sample preparation cylinder 2. The drainage seat 8 is rectangular, the sample preparation cylinder 2 is rectangular and its inner wall is also rectangular. A first permeable stone 9, a fluid-state remolded soil specimen 10, a second permeable stone 11 and a piston 3 are successively arranged on the drainage seat 8 from bottom to top. The piston 3 is slidably arranged in the sample preparation cylinder 2. A limiting plate 4 is provided at the upper end of the piston 3. The limiting plate 4 is horizontally arranged at the upper end of the piston 3. The piston 3 is rectangular. A vertical rod 6 and a weight tray 7 are successively arranged at the upper end of the limiting plate 4 from bottom to top. The vertical rod 6 is vertically arranged and the weight tray 7 is horizontally arranged. The weight tray 7 is used for placing weights. A first total drainage groove for drainage is provided on the drainage seat 8. A second total drainage groove for drainage is provided on the piston 3. A bottom plate 1 is provided at the lower end of the sample preparation cylinder 2. The cross-sectional area of the limiting plate 4 is larger than the cross-sectional area of the piston 3, and the cross-sectional area of the limiting plate 4 is larger than the cross-sectional area of the sample preparation cylinder 2. In this application, by providing a plurality of first drainage holes 201 on the outer wall of the sample preparation cylinder 2 and wrapping a filter cotton outside the sample preparation cylinder 2, it can effectively ensure that the liquid inside the specimen is discharged from the first drainage holes 201 of the sample preparation cylinder 2 and prevent the remolded soil from flowing out with the discharged liquid.

[0028] Among them, as Figure 1 and Figure 3As described above, the vertical rod 6 is a screw rod. A threaded counterbore that is threadedly engaged with the screw rod is provided at the upper end of the piston 3. A through hole for the screw rod to pass through is provided on the limiting plate 4. A threaded hole that is threadedly engaged with the screw rod is provided on the weight pan 7. The lower end of the screw rod passes through the through hole and is threadedly engaged with the threaded counterbore. A first locking nut 5 is provided on the screw rod. The limiting plate 4 is pressed against the upper end of the piston 3 by the first locking nut 5. The upper end of the screw rod is engaged with the threaded hole. A second locking nut 12 is also provided on the screw rod. The second locking nut 12 is used to lock the weight pan 7. By providing the first locking nut 5, the second locking nut 12, the through hole, the threaded counterbore, and the threaded hole, the vertical rod 6, the limiting plate 4, and the weight pan 7 are not only simply installed but also easily disassembled. On the one hand, the sample preparation efficiency is improved, and on the other hand, it is also convenient for maintenance, improving the flexibility of the device.

[0029] Specifically, as Figure 4 shown, the first total drain groove includes cruciform drain grooves A802 respectively provided on the upper and lower end faces of the drain seat 8. Four first sub-drain grooves 803 for communicating the upper and lower cruciform drain grooves A802 are provided at intervals on the circumferential side wall of the drain seat 8.

[0030] The four first sub-drain grooves 803 are respectively located on the left, right, front, and rear four faces of the drain seat 8. Define the left and right ends of the cruciform drain groove A802 as the first left drain end and the first right drain end, and the front and rear ends as the first front drain end and the first rear drain end. The two first left drain ends of the two cruciform drain grooves A802 are communicated through the first sub-drain groove 803 on the left side face of the drain seat 8. The two first right drain ends of the two cruciform drain grooves A802 are communicated through the first sub-drain groove 803 on the right side face of the drain seat 8. The two first front drain ends are communicated through the first sub-drain groove 803 on the front side face of the drain seat 8. The two first rear drain ends are communicated through the first sub-drain groove 803 on the rear side face of the drain seat 8. First rectangular drain grooves 804 that are communicated with the cruciform drain grooves A802 are respectively provided on the upper and lower end faces of the drain seat 8. A first circular drain groove 805 that is communicated with the cruciform drain groove A802 is provided inside the inner circle of the first rectangular drain groove 804. A plurality of second drain holes 801 that penetrate the upper and lower end faces of the drain seat 8 are provided in the grooves of the cruciform drain groove A802, the first rectangular drain groove 804, and the first circular drain groove 805.

[0031] In addition, as Figure 5As shown in the figure, the second main drainage groove includes cruciform drainage grooves B302 respectively arranged on the upper and lower end faces of the piston 3. Four second sub-drainage grooves 303 for connecting the upper and lower cruciform drainage grooves B302 are arranged at intervals on the circumferential side wall of the piston 3. The four second sub-drainage grooves 303 are respectively located on the left, right, front, and rear four faces of the piston 3. Define the left and right ends of the cruciform drainage groove B302 as the second left drainage end and the second right drainage end, and the front and rear ends as the second front drainage end and the second rear drainage end. The two second left drainage ends of the two cruciform drainage grooves B302 are connected through the second sub-drainage groove 303 on the left side face of the piston 3, the two second right drainage ends are connected through the second sub-drainage groove 303 on the right side face of the piston 3, the two second front drainage ends are connected through the second sub-drainage groove 303 on the front side face of the piston 3, and the two second rear drainage ends are connected through the second sub-drainage groove 303 on the rear side face of the piston 3. Second rectangular drainage grooves 304 communicating with the cruciform drainage grooves B302 are respectively arranged on the upper and lower end faces of the piston 3. Second circular drainage grooves 305 communicating with the cruciform drainage grooves B302 are arranged inside the inner circle of the second rectangular drainage grooves 304. A plurality of third drainage holes 301 penetrating the upper and lower end faces of the piston 3 are arranged in the grooves of the cruciform drainage grooves B302, the second rectangular drainage grooves 304, and the second circular drainage grooves 305. By arranging the first drainage holes 201 on the side wall of the sample preparation cylinder 2, the first main drainage groove on the drainage seat 8, and the second main drainage groove on the piston 3, the liquid inside the sample can be discharged through both ends and the side wall of the sample, effectively ensuring the uniformity of the sample. It should be noted that the parts not detailed in this application are all prior arts.

[0032] Of course, the present invention is not limited to the above-described embodiments. Several other embodiments based on the design concept of the present invention are provided below.

[0033] For example, in Embodiment 2, different from the above-described embodiment, as Figure 6 , a plurality of sample preparation cylinders 2 are provided and arranged at intervals on the upper end of the bottom plate 1, and three sample preparation cylinders 2 are provided. Three sample preparation cylinders are arranged on the bottom plate 1, and the three sample preparation cylinders can perform sample preparation work independently or simultaneously. When the three sample cylinders work simultaneously, the sample preparation efficiency is greatly improved.

[0034] For example, in Embodiment 3, different from the above-described embodiment, a water flow groove 202 is provided at the upper end of the sample preparation cylinder 2 opposite to the second sub-drainage groove 303, which is convenient for the outflow of the sample water.

[0035] The present invention also provides a sample preparation method for making a true triaxial sample of fluid remolded soil by using the above sample preparation device, including the following steps:

[0036] Step 1: Prepare fluid remolded soil. Weigh a certain amount of remolded soil, mix it with water, and prepare it into a fluid remolded soil slurry;

[0037] Step 2: Sample loading. Apply lubricating grease evenly inside the sample preparation cylinder 2, wrap filter cotton around the outside of the sample preparation cylinder 2, install the drainage seat 8 at the bottom of the sample preparation cylinder 2, place the first permeable stone 9 and filter paper in sequence at the upper end of the drainage seat 8, pour the prepared fluid remolded soil slurry into the inside of the sample preparation cylinder 2, and place filter paper, the second permeable stone 11, and the piston 3 in sequence at the top.

[0038] Step 3: Loading. Place a certain weight of weights on the top of the weight tray 7 and let it stand. The liquid inside the fluid remolded soil sample 10 will drain out through the first drainage hole 201 of the sample preparation cylinder 2, the first main drainage groove of the drainage seat 8, and the second drainage groove of the piston 3. The fluid remolded soil sample 10 undergoes consolidation settlement. When the limit plate 4 touches the top of the sample preparation cylinder 2, the preparation of the fluid remolded soil sample 10 is completed.

[0039] Step 4: Remove the fluid remolded soil sample 10. Remove the weights and the piston 3 in sequence, gently push the drainage seat 8 below the fluid remolded soil sample 10, and push the fluid remolded soil sample 10 out of the sample preparation cylinder 2.

[0040] By improving the structure of the sample preparation device, the operation process of the true triaxial sample of the present invention is made simpler, facilitating the disassembly of the sample, and effectively ensuring the integrity of the prepared sample.

[0041] It should be noted that the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention all fall within the protection scope of the present invention.

Claims

1. A device for preparing a true triaxial specimen of fluid-state remolded soil, characterized in that, Comprising: A sample preparation cylinder (2) with openings at both its upper and lower ends. A plurality of first drain holes (201) are provided on the side wall of the sample preparation cylinder (2). The outer wall of the sample preparation cylinder (2) is wrapped with filter cotton. A drain seat (8) flush with its bottom is embedded in the sample preparation cylinder (2). A first permeable stone (9), a fluid state remolded soil sample (10), a second permeable stone (11) and a piston (3) are successively arranged on the drain seat (8) from bottom to top. The piston (3) is slidably arranged in the sample preparation cylinder (2). A limiting plate (4) is provided at the upper end of the piston (3). A vertical rod (6) and a weight tray (7) are successively arranged from bottom to top at the upper end of the limiting plate (4). The weight tray (7) is used for placing weights. A first total drain groove for draining water is provided on the drain seat (8), and a second total drain groove for draining water is provided on the piston (3); The first total drain groove includes a cross-shaped drain groove A (802) respectively arranged on the upper and lower end faces of the drain seat (8). Four first sub-drain grooves (803) for communicating the upper and lower cross-shaped drain grooves A (802) are spacedly arranged on the peripheral side wall of the drain seat (8). First rectangular drain grooves (804) communicating with the cross-shaped drain groove A (802) are respectively arranged on the upper and lower end faces of the drain seat (8). A first circular drain groove (805) communicating with the cross-shaped drain groove A (802) is arranged inside the inner circle of the first rectangular drain groove (804). A plurality of second drain holes (801) penetrating through the upper and lower end faces of the drain seat (8) are provided in the grooves of the cross-shaped drain groove A (802), the first rectangular drain groove (804) and the first circular drain groove (805); The second total drain groove includes a cross-shaped drain groove B (302) respectively arranged on the upper and lower end faces of the piston (3). Four second sub-drain grooves (303) for communicating the upper and lower cross-shaped drain grooves B (302) are spacedly arranged on the peripheral side wall of the piston (3). Second rectangular drain grooves (304) communicating with the cross-shaped drain groove B (302) are respectively arranged on the upper and lower end faces of the piston (3). A second circular drain groove (305) communicating with the cross-shaped drain groove B (302) is arranged inside the inner circle of the second rectangular drain groove (304). A plurality of third drain holes (301) penetrating through the upper and lower end faces of the piston (3) are provided in the grooves of the cross-shaped drain groove B (302), the second rectangular drain groove (304) and the second circular drain groove (305); The vertical rod (6) is a screw rod. A threaded counterbore for threaded cooperation with the screw rod is provided at the upper end of the piston (3). A through hole for the screw rod to pass through is provided on the limiting plate (4). A threaded hole for threaded cooperation with the screw rod is provided on the weight tray (7). The lower end of the screw rod passes through the through hole and is in threaded cooperation with the threaded counterbore. A first locking nut (5) is provided on the screw rod. The limiting plate (4) is pressed against the upper end of the piston (3) by the first locking nut (5). The upper end of the screw rod is in cooperation with the threaded hole. A second locking nut (12) is further provided on the screw rod. The second locking nut (12) is used to lock the weight tray (7).

2. The true triaxial specimen preparation device for fluidity reshaped soil according to claim 1, characterized in that: A bottom plate (1) is provided at the lower end of the sample preparation cylinder (2).

3. The true triaxial specimen preparation device for fluidity-reshaped soil according to claim 2, characterized in that: A plurality of the sample preparation cylinders (2) are provided and are spacedly arranged at the upper end of the bottom plate (1).

4. The true triaxial specimen preparation device for fluidity reshaped soil according to claim 1, characterized in that: The cross-sectional area of the limiting plate (4) is larger than the cross-sectional area of the piston (3).

5. A method for preparing a true triaxial specimen of fluidized remolded soil using the specimen preparation device according to any one of claims 1-4, characterized in that, Including the following steps: Step 1: Prepare the fluidized remolded soil. Weigh a certain amount of remolded soil, add water, and prepare it into a fluidized remolded soil slurry. Step 2: Load the sample. Apply lubricating grease evenly inside the sample preparation cylinder (2), wrap filter cotton around the outside of the sample preparation cylinder (2), install the drainage base (8) at the bottom of the sample preparation cylinder (2), place the first permeable stone (9) and filter paper in sequence at the upper end of the drainage base (8), pour the prepared fluidized remolded soil slurry into the inside of the sample preparation cylinder (2), and place filter paper, the second permeable stone (11), and the piston (3) in sequence at the top. Step 3: Apply load. Place a certain weight of weights on the top of the weight tray (7), let it stand still. The liquid inside the fluidized remolded soil sample (10) will drain out through the first drainage hole (201) of the sample preparation cylinder (2), the first total drainage groove of the drainage base (8), and the second drainage groove of the piston (3). The fluidized remolded soil sample (10) undergoes consolidation settlement. When the limit plate (4) touches the top of the sample preparation cylinder (2), the preparation of the fluidized remolded soil sample (10) is completed. Step 4: Remove the fluidized remolded soil sample (10). Remove the weights and the piston (3) in sequence, gently push the drainage base (8) below the fluidized remolded soil sample (10), and push the fluidized remolded soil sample (10) out of the sample preparation cylinder (2).

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