Lossless extraction equipment and method for shear surface of high-water-content clay rheological test sample

Abstract

The invention discloses lossless extraction equipment and a lossless extraction method for a shear surface of a rheological test sample of high-water-content clay, and the lossless extraction equipment is characterized in that a rotational rheometer and a paddle rotor are combined for use to simulate rheological characteristics of a soil body at a high shear rate; through a plasticizing process and a lossless extraction technology, the integrity of a shear surface is effectively ensured, so that a stable basis is provided for further microstructure observation; the detachable inner frosted stainless steel sleeve, the filter paper and the permeable stone are innovatively designed, so that the wall surface slippage effect can be avoided in the shearing process, and the accuracy of a rheological test result is guaranteed; by combining a rheological testing technology, liquid nitrogen freezing and an SEM (scanning electron microscope) observation technology, high-precision microstructure analysis of the high-water-content clay shear surface sample is realized, and a brand-new technical path is provided for researching microscopic behaviors of a soil body under a dynamic shear condition.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil mechanics research and application, and particularly relates to a device and method for nondestructively extracting the shear plane of a high-water-content clay rheological test specimen. Background Art

[0002] In soil mechanics research and application, the shear plane extraction technology of clay specimens is crucial for subsequent microscopic structure observation and analysis. The existing shear plane extraction technologies have been applied in traditional soil mechanics tests, especially in conventional tests such as uniaxial compression, triaxial compression, ring shear test, and direct shear test. Most of these tests can provide relatively complete shear planes, and the extraction process is relatively simple. However, due to their low shear strain rate (the strain rate is generally lower than 0.1 s -1 ), and limited dynamic shear conditions, they fail to fully reflect the microscopic structure evolution during the shear process at high strain rates (above 1 s -1 ). More importantly, the existing technologies cannot well meet the requirements for shear plane extraction of high-water-content clay specimens in rheological tests.

[0003] Under high-water-content conditions, clay usually has high looseness and viscosity. Its shear plane is prone to roughness, irregularity, and may have adhesion phenomena, which makes it difficult to observe the microscopic structure. The shear planes after these tests are often interfered by the adhesion of the samples and the structural shear state, resulting in the inability to accurately reflect the evolution law of microscopic structure characteristics during the shear process when observed through an electron microscope. Especially in highly active clay, the agglomerate adhesion phenomenon is more significant, further exacerbating the difficulty of shear plane extraction. Summary of the Invention

[0004] The present invention provides a device and method for nondestructively extracting the shear plane of a high-water-content clay rheological test specimen, which can solve the problems existing in the prior art: Traditional rheological test technologies, especially the rotational rheological test of clay, measure inherent rheological properties such as yield stress, rate effect, and thixotropy at high shear rates, and can be closer to dynamic shear conditions. However, due to the complex forces during the rotational shear process, the shear plane after the test often cannot be extracted by the traditional method of pulling out the rotor. This not only destroys the integrity of the shear plane but may also damage the high-active structure of the clay. For the research of the above special soil bodies, such incomplete shear plane samples are difficult to accurately reflect the microscopic structure evolution law under actual shear action.

[0005] To solve the above problems, the technical solutions provided by the present invention are as follows:

[0006] An embodiment of the present invention provides a device for non-destructively extracting the shear plane of a high water content clay rheological test specimen, including a rotational rheometer, a paddle rotor, a detachable internally frosted stainless steel sleeve, filter paper, a permeable stone, and a stainless steel fixed outer collar; wherein, the stainless steel sleeve is used to fix the sample and ensure the integrity of the shear plane, and has a structure facilitating disassembly on its outside, and its internal frosted structure is used to avoid wall slip during the rotation of the rotor; the filter paper is attached to the surface of the permeable stone, the permeable stone is located at the bottom of the stainless steel sleeve, and the stainless steel fixed outer collar is used to fasten the stainless steel sleeve to ensure that the sample does not shift during the shearing process and to ensure the sealing inside the cylinder; the paddle rotor is arranged on the top of the sample and is connected to the rotational rheometer; the rotational rheometer is used to apply a preset shear force or rotational speed to simulate the dynamic rheological shearing process; the paddle rotor is used to shear the specimen, and the rotor shape is designed to suit the shearing process at a high shear rate.

[0007] In a preferred embodiment of the present invention, the diameter of the paddle rotor is 30 mm and its height is 60 mm.

[0008] In a preferred embodiment of the present invention, the inner diameter of the stainless steel sleeve is 38.5 mm and its height is 80 mm.

[0009] In a preferred embodiment of the present invention, the diameter of the permeable stone is 38.5 mm and its height is 5 mm, which is used to accelerate the drainage of water at the bottom of the sample and improve the separation effect of the shear plane.

[0010] In a preferred embodiment of the present invention, the filter paper is used to isolate solid particles, help form a clear shear plane, and ensure fluid flow.

[0011] An embodiment of the present invention provides a method for non-destructively extracting the shear plane of a high water content clay rheological test specimen, including the following steps:

[0012] Step 1, equipment assembly and sample preparation: Assemble two detachable internally frosted stainless steel sleeves together; stack the filter paper and the permeable stone in sequence at the bottom of the stainless steel sleeve to ensure their neat placement to form a support structure; fill the sample into the stainless steel sleeve, and the height of the sample should be 75 mm, and ensure that there are no air holes during the sample filling process; at this time, the sample should be in a tightly filled state to avoid voids during the shearing process.

[0013] Step 2, consolidation and water drainage: Under the action of self-weight stress, consolidate the sample for 4 hours, and the consolidation time can be adjusted according to the permeability of the clay; for clays with better permeability, sufficient plasticization effect can be achieved through 2-hour consolidation; after consolidation, the free water at the bottom of the sample will be drained, and the aquifer at the bottom about 2 mm is close to the plastic limit state to ensure non-destructive separation of the shear plane.

[0014] Step 3, Connect the paddle rotor and start shearing: Connect the paddle rotor to the rotational rheometer and gradually penetrate the rotor into the sample; according to the test requirements, formulate a shear rheology program and start applying shear stress.

[0015] Step 4, Shearing process and stopping: Under the formulated rheology program, conduct a steady-state shear test; by controlling the number of revolutions of the blades of the paddle rotor, the cumulative strain can be controlled, and the shearing can be stopped when the blades rotate 2 to 10 circles, and the connection state between the rotational rheometer and the paddle rotor is maintained; the shear strain rate can be taken as 0.01 - 200 s -1 ;

[0016] Step 5, Appearance and extraction of the shear plane: One minute after the shear program stops, disassemble the two detachable stainless-steel sleeves with internal frosted surfaces. At this time, the columnar shear plane has appeared; gently lift the paddle rotor, and the bottom of the shear plane is completely presented, and a non-damaged shear plane can be seen.

[0017] Step 6, Cut the sample and prepare for observation: Cut the shear plane sample according to the standard size of 2 mm × 5 mm for microscopic structure observation; after the shear plane sample is prepared, continue with subsequent analysis.

[0018] Step 7, Freeze the sample with liquid nitrogen: Conduct liquid nitrogen freezing treatment on the obtained shear plane sample to ensure the stability of the shear plane sample during microscopic observation and avoid sample deformation during the analysis process.

[0019] Step 8, Observe the sample with a scanning electron microscope (SEM): Observe the frozen shear plane sample with a scanning electron microscope (SEM) to study the microscopic structure changes of the sample and the microscopic behavior of the soil mass during the shearing process.

[0020] Compared with the prior art, the embodiments of the present invention provide a device and method for non-destructively extracting the shear plane of a high water content clay rheology test specimen, having the following beneficial effects: The present invention can successfully extract the post-test shear plane without damaging the shear plane structure, providing complete sample support for subsequent microscopic structure observation; this technological breakthrough will greatly improve the accuracy of microscopic structure research and provide an important theoretical and experimental basis for the shear mechanical properties of soil masses, structural failure mechanisms, and related engineering applications. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1Schematic diagram of functional components of a device for non-destructively extracting the shear plane of a high water content clay rheological test specimen provided by an embodiment of the present application.

[0023] Figure 2 Flow chart of each step of a method for non-destructively extracting the shear plane of a high water content clay rheological test specimen provided by an embodiment of the present application. Figure 2 In (a), it is a schematic diagram of preparing a sample, plasticizing with bottom drainage, and inserting a slurry rotor. Figure 2 In (b), it is a schematic diagram of programming. Figure 2 In (c), it is a schematic diagram of separating the shear plane. Figure 2 In (d), it is to cut the sample and freeze it with liquid nitrogen. Figure 2 In (e), it is a schematic diagram of SEM observation.

[0024] Figure 3 Schematic diagram of the rheological test principle of a method for non-destructively extracting the shear plane of a high water content clay rheological test specimen provided by an embodiment of the present application. Figure 3 In (a), it is the improved system. Figure 3 In (b), it is the schematic diagram of the shear bottom principle of the blade type fixture. Figure 3 In (c), it is the partial enlarged view of the detachable inner frosted sleeve.

[0025] Figure 4 Schematic diagram of the observation effect of the microscopic structure of the sample shear plane provided by an embodiment of the present application. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of the present application. When referring to "upper", "lower", "front", "rear", "left", "right", etc. for the installation position or direction of the structure or components in this embodiment, it is based on the orientation of the given drawings. They are only for the convenience of description to distinguish the relative positions of the components or directions, and do not represent the orientation when the device or components in this embodiment are used.

[0027] Importance of complete extraction of shear plane: The core significance of complete extraction of the shear plane lies in providing accurate and real specimens for microstructural research to analyze the internal mechanism of soil structural failure. In the research of various special soil types, such as collapsible loess, near-shallow seabed clay, deep-sea sediments, etc., microstructural observation is crucial. These soils have relatively complex structural characteristics in their natural state, and shear action may cause significant structural changes. Therefore, obtaining a complete shear plane has important scientific value for studying the influencing factors of shear stress and the mechanism of structural failure. 1. Collapsible loess: Collapsible loess is prone to sudden structural collapse after being invaded by water, and its microstructural evolution is closely related to shear action. By observing the shear plane, the pore changes, particle rearrangement, and moisture action mechanism of loess under different stress paths can be analyzed, providing an experimental basis for the prediction and prevention of loess collapsibility. 2. Near-shallow seabed clay: Near-shallow seabed clay undergoes complex shear stress actions under environmental effects such as tides and storm surges. Studying the microstructural evolution on the shear plane helps to understand the thixotropy, shear strength change, and seabed stability of clay, and thus provides data support for ocean engineering construction. 3. Deep-sea sediments: Due to the long-term influence of sedimentation compaction and extreme environments, deep-sea sediments exhibit special rheological properties. In engineering such as deep-sea mining and submarine pipeline laying, it is necessary to clarify the deformation mode of sediments under high shear rates. The complete extraction technology of the shear plane can provide real shear structure specimens to help study the shear softening characteristics of sediments and the mechanism of submarine landslides.

[0028] Therefore, an apparatus for non-destructively extracting the shear plane of a rheological test specimen of high water content clay is provided in an embodiment of the present invention. As Figure 1 、 Figure 2 and Figure 3As shown in the figure, the device for non-destructively extracting the shear surface of the specimen includes a rotational rheometer, a paddle rotor 4, a detachable stainless-steel sleeve 2 with internal frosting, a filter paper, a permeable stone 3, and a stainless-steel fixed outer collar 1. Among them, the stainless-steel sleeve 2 is used to fix the sample 5 and ensure the integrity of the shear surface. It has a structure that facilitates disassembly on the outside, and its internal frosting structure is used to avoid wall slip during the rotation of the rotor. The filter paper is attached to the surface of the permeable stone 3. The permeable stone 3 is located at the bottom of the stainless-steel sleeve 2. The stainless-steel fixed outer collar 1 is used to fasten the stainless-steel sleeve 2 to ensure that the sample 5 does not shift during the shearing process and to ensure the sealing inside the cylinder. The paddle rotor 4 is arranged on the top of the sample 5 and is connected to the rotational rheometer. The diameter of the paddle rotor 4 is 30 mm, and its height is 60 mm. The inner diameter of the stainless-steel sleeve 2 is 38.5 mm, and its height is 80 mm. The diameter of the permeable stone 3 is 38.5 mm, and its height is 5 mm. The device for non-destructively extracting the shear surface in this embodiment is based on the rotational rheometer platform and is equipped with a specially designed paddle rotor and supporting accessories. The rotational rheometer is used to apply a preset shear force or rotational speed to simulate the dynamic rheological shear process. The paddle rotor 4 is used to shear the specimen, and the rotor shape is designed to suit the shearing process at high shear rates. The filter paper is used to isolate solid particles, help form a clear shear surface, and ensure fluid flow. The permeable stone is used to accelerate the drainage of moisture at the bottom of the sample and improve the separation effect of the shear surface.

[0029] Reference Figure 2 and Figure 3 , the embodiment of the present invention provides a method for non-destructively extracting the shear surface of a high-water-content clay rheological test specimen, including the following steps:

[0030] Step 1, equipment assembly and sample preparation: Assemble two detachable stainless-steel sleeves 2 with internal frosting together; stack the filter paper and the permeable stone 3 in sequence at the bottom of the stainless-steel sleeve 2 to ensure their neat placement to form a support structure; fill the sample into the stainless-steel sleeve 2, and the height of the sample 2 should be 75 mm, and ensure that there are no air holes during the sample filling process; at this time, the sample should be in a tightly filled state to avoid voids during the shearing process.

[0031] Step 2, consolidation and moisture drainage: Under the action of self-weight stress, consolidate the sample for 4 hours, and the consolidation time can be adjusted according to the permeability of the clay; for clays with better permeability, sufficient plasticization effect can be achieved through 2-hour consolidation; after consolidation, the free water at the bottom of the sample will be drained, and the aquifer at the bottom about 2 mm is close to the plastic limit state to ensure non-destructive separation of the shear surface.

[0032] Step 3, connect the paddle rotor 4 and start shearing: Connect the paddle rotor 4 to the rotational rheometer and start gradually penetrating the rotor into the sample; according to the test requirements, formulate a shear rheology program and start applying shear stress.

[0033] Step 4, Shearing Process and Stopping: Under the formulated rheological program, a steady-state shearing test is carried out; by controlling the blade rotation speed of the paddle rotor 4, the cumulative strain can be controlled, and the shearing can be stopped when the blade rotates 2 to 10 circles, and the connection state between the rotational rheometer and the paddle rotor 4 is maintained; the shearing strain rate can be taken as 0.01 to 200 s -1 ;

[0034] Step 5, Appearance and Extraction of the Shearing Surface: One minute after the shearing program stops, the two detachable stainless-steel sleeves 2 with internal frosting are disassembled. At this time, the columnar shearing surface has appeared; gently lift the paddle rotor 4, and the bottom of the shearing surface is completely presented, and a non-damaged shearing surface can be seen.

[0035] Step 6, Cutting the Specimen and Preparing for Observation: Cut the shearing surface sample according to the standard size of 2 mm × 5 mm for microscopic structure observation; after the shearing surface sample is prepared, continue with subsequent analysis;

[0036] Step 7, Freezing the Sample with Liquid Nitrogen: The obtained shearing surface sample is treated with liquid nitrogen freezing to ensure the stability of the shearing surface sample during microscopic observation and avoid sample deformation during the analysis process;

[0037] Step 8, Observing the Sample with a Scanning Electron Microscope (SEM): Observe the frozen shearing surface sample with a scanning electron microscope (SEM) to study the microscopic structure changes of the sample and the microscopic behavior of the soil body during the shearing process.

[0038] The solution of the present invention uses the combined use of a rotational rheometer and a paddle rotor to simulate the rheological properties of the soil body under high shearing rates. Through the plasticization process and the non-destructive extraction technology, the integrity of the shearing surface is effectively ensured, thus providing a stable basis for further microscopic structure observation. The innovatively designed detachable stainless-steel sleeves with internal frosting, filter paper, and permeable stones can avoid the wall slip effect during the shearing process and ensure the accuracy of the rheological test results. At the same time, the integrity of the sample is maintained, and the free water at the bottom is effectively drained, making the water content of the shearing surface lower than the liquid limit water content to prevent the adhesion of the shearing surface. The present invention also combines rheological test technology, liquid nitrogen freezing, and SEM observation technology to achieve high-precision microscopic structure analysis of the shearing surface sample of high-water-content clay, providing a new technical path for studying the microscopic behavior of the soil body under dynamic shearing conditions.

[0039] Example 1

[0040] Deep - sea sediments are from the sampling mission of the "Kaituo - 2" deep - sea mining vehicle during its sea trial, taken from the polymetallic nodule resource area in the western Pacific Ocean. The evolution law of its microscopic structure is the research basis for mechanical properties, playing an important supporting role in the research on the response to external loads such as bottom shear and compaction. The research on the above - mentioned properties of deep - sea sediments in polymetallic nodule mining areas can serve the development of the traveling mechanism of deep - sea mining vehicles and more research on the interaction between submarine structures and sediments. Figure 4 In (a) is the microscopic structure of undisturbed bottom sediment sampled by box - corer; Figure 4 In (b) is the "tearing" effect under shear at a low strain rate (0.1s -1 ), caused by stress concentration along the weak zone; Figure 4 In (c) is the "accumulation" effect under low - strain - rate shear, reflecting that the low - strain rate is greatly affected by the anisotropy of the bottom sediment; Figure 4 In (d) is the brittle fracture of flocs under high - strain - rate (10s -1 ) shear. In the corresponding tests of the four observation diagrams, the cumulative strain was controlled, that is, the shear stopped when the paddle rotated 4 full circles.

[0041] The observation results of the frozen SEM images of the bottom - sediment shear plane and undisturbed bottom sediment show that the shear behavior has a significant impact on the particle, pore morphology characteristics, and structural arrangement of the bottom - sediment shear plane. At low strain rates, the shear plane shows local faults and accumulation, the pore distribution is uneven, the pore directionality in local areas is enhanced, and the long axis of the pores is enriched perpendicular to the shear direction; while at high strain rates, the pores and particle arrangement on the shear plane are more uniform, the long axis of the pores is significantly enriched tangentially along the shear direction, and the shear action weakens the heterogeneity of the bottom sediment. In addition, the quantification results of microscopic characteristics show that the pore fractal dimension of the shear - plane sample is lower than that of the undisturbed sample, reflecting the characteristics of macroscopic pore compression and lower microscopic pore - morphology complexity; the particle fractal dimension decreases significantly at high strain rates, showing that the particle surface tends to be smoothed and tiled along the shear plane.

[0042] The direct technical effects brought by the core technical solution of the present invention are as follows: (1) The present invention adopts the non - destructive extraction technology for the shear plane of high - water - content clay rheological test specimens, effectively improving the integrity of the microscopic structure of the shear plane at high shear rates (up to 200s - 1), and successfully avoiding the problems of particle agglomeration and adhesion on the shear plane. Compared with traditional test methods, the direct technical effects of this solution include: (2) Expanding the measurable shear - strain - rate range: from the traditional soil - mechanics test only applicable to low shear rates of ≤0.1s - 1 to 0.01 - 200s -1. It covers five orders of magnitude and can meet the needs of deep-sea sediment and high strain rate shear research. (3). Improved the integrity of shear plane extraction: The microstructure of the shear plane sample remains intact, successfully avoiding the problems of aggregate adhesion, particle breakage, and structural collapse caused by traditional methods, making the microstructure analysis more accurate.

[0043] The general technical effects of the present invention are as follows: The shear plane non-destructive extraction technology of the present invention significantly optimizes the shear plane integrity and microstructure stability of high water content clay in rheological tests. The specific technical effects include: Improving the accuracy of microstructure analysis: The pores and particle arrangements on the shear plane are uniform, avoiding the distortion of the microscopic morphology caused by sample damage. Supporting a wider range of shear research: The observable strain rate (10s - 1 - 200s - 1) The shear plane after shearing provides a new means for studying the soil deformation mechanism under the action of shear stress. Optimizing deep-sea sediment research: This method is particularly suitable for the shear plane analysis of deep-sea sediments, contributing to the mechanical research in the fields of submarine engineering, seabed stability, and deep-sea mining. Pioneering breakthrough: Compared with traditional direct shear and ring shear tests, this solution realizes the microscopic extraction technology of the shear plane at high shear rates for the first time, filling this research gap.

[0044] The comparative analysis with the prior art is as follows: (1). The limitations of traditional direct shear and ring shear tests. Traditional direct shear and ring shear tests are only applicable to low shear rates (≤0.1s - 1), and their shear plane structure integrity is relatively high, but they are not applicable to the rheological research of soils at high shear rates. At low shear rates, the microscopic structure of the shear plane is easily affected by anisotropy, showing phenomena such as local faults and uneven pores ( Figure 4 (as shown in (b) and (c)). Due to the relatively fragile shear plane sample, it is difficult for traditional methods to avoid the agglomeration and adhesion of particles during shearing, resulting in the deviation of the observed results of the microscopic structure from the actual situation.

[0045] The technical advantages of the present invention are as follows: The shear plane non-destructive extraction technology of the present invention realizes the observation of the shear plane at high shear rates (10s - 1 - 200s - 1) for the first time, successfully expanding the applicable range of soil shear experiments ( Figure 4 as shown in (d) in the figure). At low strain rates (0.1s - 1), local fractures and accumulations still appear on the shear plane, but the pore directionality is clearer, and the long axis of the pores is perpendicular to the shear direction ( Figure 4 as shown in (c) in the figure). At high strain rates (10s -1) Under this condition, the microstructure of the shear plane becomes more uniform, the long axis of the pores is enriched along the shear direction, and the particle surface tends to be smooth. The shear action significantly reduces the anisotropy of the substrate, and local characteristics such as brittle fracture of flocs are also found ( Figure 4 in (d) of the figure). It is difficult for traditional methods to obtain a complete shear plane sample at high shear rates, while the present invention uses a low-disturbance extraction technique to successfully maintain the original structure of the shear plane sample.

[0046] The quantification technical effects of the present invention are as follows: Extension of the shear strain rate range: Compared with the traditional method which is only applicable to ≤0.1 s - -1, the present invention can realize research within a larger range of shear strain rates of 0.01 - 200 s - -1, spanning 5 orders of magnitude. Improvement of the shear plane morphology stability: Under cryo-SEM observation, the particle structure of the shear plane is clear and the pore directions are consistent, avoiding problems such as structural collapse and adhesion caused by sample damage.

[0047] Although the present invention has been disclosed above with preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those of ordinary skill in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A device for non-destructively extracting the shear plane of a high water content clay rheological test specimen, characterized in that, It includes a rotational rheometer, a paddle rotor, a detachable internally frosted stainless-steel sleeve, filter paper, a permeable stone, and a stainless-steel fixed outer collar; wherein, the stainless-steel sleeve is used to fix the sample and ensure the integrity of the shear plane, and a structure facilitating disassembly is provided on its exterior, and its internal frosted structure is used to avoid wall slip during the rotation of the rotor; the filter paper is attached to the surface of the permeable stone, the permeable stone is located at the bottom of the stainless-steel sleeve, and the stainless-steel fixed outer collar is used to fasten the stainless-steel sleeve to ensure that the sample does not shift during shearing and to guarantee the sealing inside the cylinder; the paddle rotor is arranged at the top of the sample and is connected to the rotational rheometer; the rotational rheometer is used to apply a preset shear force or rotational speed to simulate the dynamic rheological shear process; the paddle rotor is used to shear the specimen, and the rotor shape is designed to suit the shearing process at high shear rates.

2. The shear plane non-destructive extraction device for high water content clay rheological test specimens according to claim 1, characterized in that, The diameter of the paddle rotor is 30 mm and its height is 60 mm.

3. The non-destructive extraction device for the shear plane of a high water content clay rheological test specimen according to claim 2, wherein The inner diameter of the stainless-steel sleeve is 38.5 mm and its height is 80 mm.

4. The non-destructive extraction device for the shear plane of a high water content clay rheological test specimen according to claim 3, characterized in that, The diameter of the permeable stone is 38.5 mm and its height is 5 mm, which is used to accelerate the drainage of moisture at the bottom of the sample and improve the separation effect of the shear plane.

5. The shear plane non-destructive extraction device for a high water content clay rheological test specimen according to claim 4, characterized in that The filter paper is used to isolate solid particles, help form a clear shear plane, and ensure fluid flow.

6. A method for non-destructively extracting the shear plane of a high water content clay rheological test specimen, characterized in that, It includes the following steps: Step 1, equipment assembly and sample preparation: Assemble two detachable internally frosted stainless-steel sleeves together; stack the filter paper and the permeable stone in sequence at the bottom of the stainless-steel sleeve to ensure they are neatly placed to form a support structure; fill the sample into the stainless-steel sleeve, and the height of the sample should be 75 mm, and ensure that there are no air holes during the sample filling process; at this time, the sample should be in a tightly filled state to avoid voids during shearing. Step 2, consolidation and moisture drainage: Under the action of self-weight stress, consolidate the sample for 4 hours, and the consolidation time can be adjusted according to the permeability of the clay; clays with better permeability can achieve sufficient plasticization effect through 2-hour consolidation; after consolidation, the free water at the bottom of the sample will be drained, and the aquifer about 2 mm at the bottom is close to the plastic limit state to ensure the lossless separation of the shear plane. Step 3, connect the paddle rotor and start shearing: Connect the paddle rotor to the rotational rheometer and start gradually penetrating the rotor into the sample; according to the test requirements, formulate a shear rheology program and start applying shear stress. Step 4, Shearing Process and Stopping: Under the established rheological program, a steady-state shearing test is carried out; by controlling the number of revolutions of the blades of the paddle rotor, the cumulative strain can be controlled, and the shearing can be stopped when the blades rotate 2 to 10 circles, and the connection state between the rotational rheometer and the paddle rotor is maintained; the shearing strain rate can be taken as 0.01 to 200 s -1 ; Step 5, appearance and extraction of the shear plane: One minute after the shear program stops, disassemble the two detachable internally frosted stainless-steel sleeves. At this time, the columnar shear plane has appeared; gently lift the paddle rotor, and the bottom of the shear plane is completely presented, and a lossless shear plane can be seen. Step 6, cut the specimen and prepare for observation: Cut the shear plane sample according to the standard size of 2 mm × 5 mm for microscopic structure observation; after the shear plane sample is prepared, continue with subsequent analysis. Step 7, freeze the sample with liquid nitrogen: Perform liquid nitrogen freezing treatment on the obtained shear plane sample to ensure the stability of the shear plane sample during microscopic observation and avoid sample deformation during analysis. Step 8, observing the sample with a scanning electron microscope (SEM): The frozen shear plane sample is observed with a scanning electron microscope (SEM) to study the microscopic structural changes of the sample and the microscopic behavior of the soil during the shearing process.

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