A device for preparing reshaped clay samples with inclined deposition surface

Abstract

The present invention belongs to the field of geotechnical testing, and relates to a device for preparing a reshaped clay sample with an inclined deposition surface, which is used to consolidate a fluidized soil sample into a geotechnical sample, and includes a sample molding system, a power drive system, and a consolidation drainage system; the fluidized soil sample is installed in the sample molding system, and the power drive system drives the sample molding system to rotate and generate centrifugal force, and the consolidation drainage system is arranged outside the sample molding system, and the excess water in the sample molding system is discharged through the consolidation drainage system. The present invention can achieve quantitative control of the inclination angle of the deposition surface of the sample, and is suitable for the preparation of reshaped samples; it can also be used in conjunction with existing geotechnical sample preparation technologies (sampling method, coring method, etc.) to solve the problem of preparing hollow cylindrical clay samples with inclined deposition surfaces.

Description

Technical Field

[0001] The invention belongs to the field of geotechnical tests and relates to a device for preparing a reshaped clay sample with an inclined deposition surface. Background Art

[0002] In actual engineering, the phenomenon of stress loading in different directions is very common. Studies have shown that when stress is loaded in different directions, the mechanical properties of soil are different.

[0003] In indoor experiments, the basic tests for studying the mechanical properties of soil include direct shear test, triaxial test, true triaxial test and hollow cylinder torsion shear test. For undisturbed and remolded clay, the direction of the major principal stress is usually perpendicular to the deposition surface. Most tests cannot consider the effect of the stress direction angle on the mechanical properties of soil when loading in different directions.

[0004] It should be pointed out that although the hollow cylindrical torsion shear apparatus can take into account the influence of a stress direction angle, in actual engineering, due to geological effects, the sedimentary surface of the soil often tilts. Therefore, the phenomenon that the sedimentary surface tilts in one direction and the stress deflects in another direction is extremely common.

[0005] People have realized the importance of this characteristic of soil and have carried out some research. For remolded sand samples, the inclined sand filling method can be used to prepare samples with inclined sedimentary surfaces, and some results have been achieved. However, there is no standardized device in the prior art that can effectively prepare remolded clay samples with inclined sedimentary surfaces. Summary of the invention

[0006] In view of this, an object of the present invention is to provide a device for preparing a reshaped clay sample with an inclined deposition surface, which can prepare a standardized cylindrical or hollow cylindrical reshaped clay sample with an inclined deposition surface.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A geotechnical sample preparation device with an inclined deposition surface is used to consolidate a fluidized soil sample into a geotechnical sample, comprising a sample molding system, a power drive system, and a consolidation drainage system; the fluidized soil sample is installed in the sample molding system, the power drive system drives the sample molding system to rotate and generate centrifugal force, the consolidation drainage system is arranged outside the sample molding system, and excess water in the sample molding system is discharged from the consolidation drainage system.

[0009] Optionally, the sample molding system includes an inner cylinder and a middle cylinder; the inner cylinder matches the middle cylinder and is fixedly connected.

[0010] Optionally, mutually matching water-permeable plates are provided at positions where the inner tube matches the middle tube.

[0011] Optionally, the outer side wall of the inner tube and the inner side wall of the middle tube are provided with mutually matching protrusions and grooves for limiting the tangential degree of freedom between the inner tube and the middle tube.

[0012] Optionally, the inner cylinder includes an inner cylinder top cover, an inner cylinder wall and an inner cylinder base.

[0013] Optionally, the water-permeable plate and the base are composed of small copper balls (with a diameter of less than 1 mm), which have a certain strength and can ensure that only liquid permeates out while solid particles are retained inside.

[0014] Optionally, the power drive system includes an interconnected motor, a conveyor belt, and a speed reducer separator. The torque of the motor is transmitted to the speed reducer separator through the conveyor belt, and the sample molding system is driven to rotate through the speed reducer separator.

[0015] Optionally, it also includes a support shock-absorbing system, which is arranged outside the sample molding system and includes a closed support outer cylinder, and the inner wall of the closed support outer cylinder is connected to the sample molding system through a shock-absorbing rod.

[0016] Optionally, the consolidation drainage system includes a drain pipe, a drain trough, and a drain hole; the drain pipe is located at the bottom between the specimen molding system and the support and shock absorption system, and is used to collect the liquid discharged by the specimen molding system; the drain trough is below the drain pipe, and a drain hole is provided at the bottom thereof, and the liquid is discharged from the device through the drain hole.

[0017] Optionally, it also includes a vacuum loading system; the vacuum loading system includes a semipermeable membrane, a vacuum pump, a vacuum tube, and an exhaust hole; the semipermeable membrane is arranged in the sample molding system and wraps the fluidized soil sample; an airtight space is formed between the semipermeable membrane and the closed supporting outer cylinder, the vacuum tube is connected to the closed space, and the vacuum pump extracts air and moisture from the airtight space through the vacuum tube, the moisture passes through the consolidation drainage system, and the air is discharged through the exhaust hole.

[0018] Optionally, an electrical control system is also included for digitally controlling the output speed of the power drive system and the vacuum pressure of the vacuum loading system.

[0019] The beneficial effects of the present invention are:

[0020] The present invention can achieve quantitative control of the inclination angle of the sample's deposition surface, and is suitable for the preparation of reshaped samples; it can also be used in conjunction with existing geotechnical sample preparation techniques (sampling method, coring method, etc.) to solve the problem of preparing clay hollow cylindrical samples with inclined deposition surfaces.

[0021] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 It is a cross-sectional view of the inner cylinder of the present invention;

[0025] Figure 3 It is a cross-sectional view of the inner cylinder of the present invention;

[0026] Figure 4 is a cross-sectional view of the middle tube of the present invention;

[0027] Figure 5 A top view of the inner cylinder base of the present invention;

[0028] Figure 6 A top view of the middle tube base of the present invention;

[0029] Figure 7 It is a cross-sectional view of the closed support outer cylinder of the present invention;

[0030] Figure 8 It is a schematic diagram of the stress condition of the fluid-plastic soil sample in the present invention. DETAILED DESCRIPTION

[0031] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0032] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0033] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is 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 operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0034] See also Figure 1-Figure 6 The component numbers in the accompanying drawings respectively represent: sample molding system 1, inner cylinder 11, middle cylinder 12, inner cylinder base 13, inner cylinder wall 14, permeable plate 15, protrusion 16, groove 17, inner cylinder top cover 19, middle cylinder top cover 10, middle cylinder base 18, support shock absorption system 2, shock absorption rod 21, closed support outer cylinder 22, power drive system 3, conveyor belt 31, motor 32, speed reduction separator 33, vacuum loading system 4, semipermeable membrane 40, vacuum pump 41, vacuum tube 42, exhaust hole 43, consolidation drainage system 5, drainage pipe 51, sump 52, drainage hole 54, geotechnical sample 6, electrical control system 7.

[0035] The sample molding system 1 is used to hold the geotechnical sample 6 and construct the drainage consolidation channel of the geotechnical sample 6. The inner cylinder 11 is composed of the inner cylinder top cover 19, the inner cylinder wall 14 and the inner cylinder base 13, and is mainly used for molding the geotechnical sample 6. The permeable plate 15, the permeable plate 131 and the permeable plate 181 can be composed of copper balls (with a diameter of less than 1 mm), which have a certain strength and can ensure that only liquid permeates out while solid particles are retained inside.

[0036] The geotechnical sample 6 (clay sample) is wrapped with a semi-permeable membrane 40 and placed in the inner tube 11. The outer side of the inner tube wall 14 of the inner tube 11 is cross-arranged with protrusions 16 and grooves 17, which have the function of fixedly connecting the inner tube 11 with the middle tube 12, so that the permeable plate 15 of the inner tube 11 overlaps with the permeable plate 15 of the middle tube 12, forming a lateral drainage channel for the geotechnical sample 6. At the same time, the protrusions 16 and the grooves 17 constitute the connecting slide rails between the inner tube 11 and the middle tube 12, so that the inner tube 11 can be directly taken out of the middle tube 12 when loading and sampling. The top of the middle tube 12 is provided with a middle tube top cover 10 that fits with the inner tube top cover 19, and the bottom of the middle tube 12 is provided with a middle tube base 18 that fits with the inner tube base 13.

[0037] The permeable plate 15 of the inner tube 11 fits with the permeable plate 15 of the middle tube 12 to form a lateral drainage channel for the geotechnical sample 6. The inner tube base 13 is located below the inner tube 11, and the drainage plate 131 on the inner tube base 13 fits with the drainage plate 181 on the middle tube base 18 to form a vertical drainage channel for the geotechnical sample 6.

[0038] The support and shock absorption system 2 is composed of a shock absorption rod 21 and a closed support outer cylinder 22. The shock absorption rod 21 with flexible shock absorption function connects the middle cylinder 12 with the closed support outer cylinder 22 to provide support and protection for the geotechnical sample 6, reduce the vibration of the sample molding system 1 during operation, and improve the stability of the sample. The closed support outer cylinder 22 has good air tightness.

[0039] The power drive system 3 mainly provides the power required for sample preparation. The motor 32 provides a stable speed output, which is transmitted to the deceleration separator 33 by the conveyor belt 31, and the deceleration separator 33 adjusts the speed to the speed required for sample preparation, thereby driving the sample molding system 1 to rotate. While the sample molding system 1 rotates, the excess liquid inside the geotechnical sample 6 is thrown out by the vacuum negative pressure on the outside and the rotational overpressure inside, thereby realizing the accelerated consolidation of the geotechnical sample 6.

[0040] The vacuum loading system 4 reduces the air pressure of the sample molding system 1 to the pressure required for sample preparation, thereby accelerating the consolidation of the geotechnical sample 6 and improving the sample preparation efficiency. The semipermeable membrane 40 is a flexible film located inside the inner tube 11 that only allows water and air to pass through, while solid particles cannot pass through. The closed support outer tube 22 has good air tightness. A closed space is formed between the semipermeable membrane 40 and the closed support outer tube 22. The exhaust hole 43 is located at the upper part of the closed support outer tube 22 and is connected to the vacuum pump 41 through the vacuum tube 42. The vacuum pump 41 continuously extracts air, thereby forming a closed space between the semipermeable membrane 40 and the closed support outer tube 22 to apply negative pressure, squeeze out the liquid inside the geotechnical sample 6, and accelerate the consolidation of the geotechnical sample 6.

[0041] The consolidation drainage system 5 collects the liquid discharged by the sample molding system 1 and discharges it to the outside of the instrument through a pipe. The drainage pipe 51 is located at the bottom between the middle cylinder 12 and the closed support outer cylinder 22, and is used to collect the liquid discharged by the sample molding system 1. The sump 52 is below the drainage pipe 51, and a drainage hole 54 is provided at its bottom, through which the liquid is finally discharged from the instrument.

[0042] The geotechnical sample 6 has a central symmetry characteristic. Under the action of gravity and centrifugal force, the normal direction of its consolidation surface (i.e., the direction of N) forms a specific angle with the central axis, which is the angle between the consolidation surface of the geotechnical sample 6 and the horizontal plane. The electrical control system 7 includes electronic components such as a program controller and a circuit board, and can realize digital control of the output speed of the power drive system 3 and the vacuum pressure of the vacuum loading system 4 through manual operation.

[0043] The operation steps of the present invention are as follows:

[0044] A. Prepare the fluidized soil sample. Dry and crush the clay sample, pass it through a 2mm geotechnical sieve, take the fine powder particles and add water to prepare a mud soil sample.

[0045] B. Loading soil samples. Load the fluidized soil sample into the semipermeable membrane 40, and then put the semipermeable membrane 40 into the inner tube 11. The inner tube 11 and the middle tube 12 are engaged and connected by means of the protrusions 16 and the grooves 17, so that the inner tube 11 and the middle tube 12 become a closed whole.

[0046] C. Consolidation sample preparation. Operate the electrical control system 7 to control the power drive system 3. The motor 32 provides a stable speed output, which is transmitted to the deceleration separator 33 by the conveyor belt 31, and the deceleration separator 33 adjusts the speed to the speed required for sample preparation. The permeable plate 15 of the inner tube 11 fits with the permeable plate 15 of the middle tube 12 to form a lateral drainage channel for the geotechnical sample 6; the drainage plate 131 on the inner tube base 13 and the drainage plate 181 on the middle tube base 18 fit together to form a vertical drainage channel for the geotechnical sample 6. The inner tube base 13 is a vertical drainage channel. The excess liquid inside the geotechnical sample 6 is discharged to the consolidation drainage system 5 through the lateral and vertical drainage channels by gravity acceleration and rotational acceleration. It is collected in the sump 52 through the drainage pipe 51. In order to accelerate the consolidation of the geotechnical sample 6, the electrical control system 7 can be operated as needed to control the vacuum loading system 4 to apply negative pressure to the closed space between the semipermeable membrane 40 and the outer cylinder, so that the liquid inside the geotechnical sample 6 penetrates from the inside of the geotechnical sample 6 to the consolidation drainage system 5 due to the pressure difference between the inside and outside of the semipermeable membrane 40.

[0047] D. Sample removal. After consolidation is completed, the inner cylinder 11 is taken out together with the geotechnical sample 6 and the semipermeable membrane 40 therein. Then, the semipermeable membrane 40 is taken out from the inner cylinder 11 with the geotechnical sample 6 therein. The semipermeable membrane 40 is opened and the geotechnical sample 6 therein is taken out.

[0048] E. Sample cutting. Use common geotechnical sample preparation tools such as geotechnical knives and wire bows to cut the removed geotechnical sample 6 into a cylindrical shape for experimental research. The cylindrical sample can also be cored by a sample corer to form a hollow cylindrical sample.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A device for preparing a reshaped clay sample with an inclined deposition surface, used for consolidating a fluidized plastic soil sample into a geotechnical sample, characterized in that: It includes a sample molding system, a power drive system, and a consolidation and drainage system; the fluidized soil sample is installed in the sample molding system, the power drive system drives the sample molding system to rotate and generate centrifugal force, the consolidation and drainage system is arranged on the outside of the sample molding system, and the excess water in the sample molding system is discharged through the consolidation and drainage system; the sample molding system includes an inner cylinder and a middle cylinder; the inner cylinder matches the middle cylinder and is fixedly connected; a mutually matching permeable plate is provided at the position where the inner cylinder matches the middle cylinder; the outer wall of the inner cylinder and the inner wall of the middle cylinder are provided with mutually matching protrusions and grooves for limiting the tangential freedom between the inner cylinder and the middle cylinder; the inner cylinder includes an inner cylinder top cover, an inner cylinder wall and an inner cylinder base.

2. The device for preparing a reshaped clay sample with an inclined deposition surface as claimed in claim 1, characterized in that: The power drive system includes an electric motor, a conveyor belt, and a deceleration separator which are connected to each other. The torque of the electric motor is transmitted to the deceleration separator through the conveyor belt, and the sample molding system is driven to rotate through the deceleration separator.

3. The device for preparing a reshaped clay sample with an inclined deposition surface as claimed in claim 1, characterized in that: It also includes a support and shock-absorbing system, which is arranged outside the sample molding system and includes a closed support outer cylinder, and the inner wall of the closed support outer cylinder is connected to the sample molding system through a shock-absorbing rod.

4. The device for preparing a reshaped clay sample with an inclined deposition surface as claimed in claim 3, characterized in that: The consolidation drainage system includes a drainage pipe, a drainage trough, and a drainage hole; the drainage pipe is located at the bottom between the sample molding system and the support and shock absorption system, and is used to collect the liquid discharged by the sample molding system; the drainage trough is below the drainage pipe, and a drainage hole is provided at the bottom thereof, through which the liquid is discharged from the device.

5. The device for preparing a reshaped clay sample with an inclined deposition surface as claimed in claim 3, characterized in that: It also includes a vacuum loading system; the vacuum loading system comprises a semipermeable membrane, a vacuum pump, a vacuum tube, and an exhaust hole; the semipermeable membrane is arranged in the sample molding system and wraps the flow-plastic sample; an airtight space is formed between the semipermeable membrane and the closed supporting outer cylinder, the vacuum tube is connected to the closed space, and the vacuum pump extracts air and moisture from the airtight space through the vacuum tube, the moisture passes through the consolidation drainage system, and the air is discharged through the exhaust hole.

6. The device for preparing a reshaped clay sample with an inclined deposition surface as claimed in claim 5, characterized in that: It also includes an electrical control system for digitally controlling the output speed of the power drive system and the vacuum pressure of the vacuum loading system.

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