Full-transparent rock-soil circumferential shear test instrument and use method thereof

Abstract

The invention discloses a full-transparent rock-soil circumferential shear test instrument and a use method thereof, and relates to the technical field of circumferential shear tests.The full-transparent rock-soil circumferential shear test instrument comprises a transparent circumferential shear box, a loading system and an imaging system; an inner cavity with an annular section is constructed in the transparent circumferential shearing box, the inner cavity is used for accommodating a transparent sample, the bottom wall of the inner cavity is made of a transparent material, and the annular inner wall or the annular outer wall of the inner cavity is made of a transparent material; the imaging system comprises an annular laser transmitter and a plurality of cameras; the annular laser emitter is arranged below the inner cavity and can emit laser towards the inner cavity from the bottom wall of the inner cavity, and the cameras are arranged outside the inner cavity and can shoot image information in the inner cavity through the annular inner wall or the annular outer wall; the loading system is configured to shear the specimen in the lumen along the circumferential direction. According to the invention, the large deformation damage visualization of the soil body sample under a certain stress state can be realized, namely, the large deformation shear damage process in the sample can be directly observed.

Description

Technical Field

[0001] The invention relates to the technical field of circumferential shear testing, and in particular to a fully transparent rock and soil circumferential shear testing instrument and a use method thereof. Background Art

[0002] As a special test method in the field of geotechnical engineering, the circumferential shear test is mainly used to simulate the development process of shear slip surfaces or sliding layers in nature, especially to study the shear strength changes and residual strength characteristics of soil under large displacement conditions. However, when geological disasters such as landslides and debris flows occur, obvious local shear zones will be generated. When using a circumferential shear instrument, the failure mechanism can only be inferred from the sample surface or from the sample section after failure, which is highly subjective. Summary of the invention

[0003] The purpose of the present invention is to provide a fully transparent rock and soil annular shear test instrument and a method of using the same, so as to solve the problems existing in the above-mentioned prior art and realize the visualization of the shear failure process.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a fully transparent rock and soil circumferential shear test instrument, comprising: a transparent circumferential shear box, a loading system and an imaging system; the transparent circumferential shear box is configured with an inner cavity with an annular cross-section, the inner cavity is used to accommodate a transparent sample, the bottom wall of the inner cavity is made of a transparent material, and the annular inner wall or the annular outer wall of the inner cavity is made of a transparent material; the imaging system comprises an annular laser emitter and a plurality of cameras; the annular laser emitter is arranged below the inner cavity and can emit laser from the bottom wall of the inner cavity into the inner cavity, the plurality of cameras are arranged outside the inner cavity, and the cameras can capture image information in the inner cavity through the annular inner wall or the annular outer wall; the loading system is configured to shear the sample in the inner cavity along the annular direction.

[0006] Preferably, it also includes a base, the top of the base is constructed with a boss, the transparent annular shear box is detachably arranged on the top of the boss, the annular laser emitter is sleeved and fixed outside the boss, and the annular laser emitter emits annular laser vertically upward.

[0007] Preferably, the loading system includes an axial actuator, a torsional actuator, a force transmission rod and a torsional cover; the bottom of the force transmission rod and the torsional cover are detachably connected, the bottom structure of the torsional cover is constructed as an annular structure with the same size and shape as the inner cavity, and in an initial state, the torsional cover is located directly above the inner cavity, and a plurality of tooth structures are provided on the bottom surface of the annular structure, the axial actuator is constructed to drive the force transmission rod to drive the torsional cover to move up and down, and the torsional actuator is constructed to drive the force transmission rod to drive the torsional cover to rotate, and the tooth structure extends radially along the annular structure.

[0008] Preferably, two opposite and vertically arranged columns are fixedly provided on the base, a top plate is fixedly provided on the top of the two columns, the axial actuator and the torsional actuator are fixedly provided on the top plate, the force transmission rod is vertically arranged, the force transmission rod includes a rod head and a rod body, the rod head and the rod body are rotatably connected around a vertical axis, the axial actuator is transmission connected to the rod head and drives the rod head to move up and down, and the torsional actuator is transmission connected to the rod body and drives the rod body to rotate around the vertical axis.

[0009] Preferably, the transparent annular shear box includes the annular inner wall, the annular outer wall and the bottom plate, the annular inner wall and the annular outer wall are vertically fixed on the bottom plate, the bottom wall of the inner cavity is formed on the bottom plate, the bottom plate is detachably arranged on the boss, and the camera is fixedly arranged on the bottom plate outside the annular outer wall.

[0010] Preferably, the annular inner wall, the annular outer wall and the bottom plate are made of transparent acrylic or tempered glass.

[0011] Preferably, the annular laser emitter emits an annular laser curved surface from bottom to top; the annular laser curved surface passes through the bottom wall of the inner cavity into the transparent sample to form a high-brightness speckle field; and the shooting focus axes of the multiple cameras coincide with the normal direction of the high-brightness speckle field.

[0012] Preferably, the twist cover comprises a cover body and an annular pad fixedly arranged on the bottom edge of the cover body, and the annular pad is made of metal or a cement mortar block.

[0013] Preferably, the twist cover is provided with air holes, and the boss is provided with a pressure sensor and a torque sensor.

[0014] The present invention also provides a method for using the fully transparent rock and soil annular shear test instrument as described above, comprising:

[0015] preparing a transparent specimen in the inner cavity;

[0016] Turn on the ring laser transmitter and multiple cameras, turn off all other light sources in the environment, and adjust the exposure and focus of multiple cameras to make the bright speckle field clearly visible;

[0017] The loading system shears the sample in the inner cavity along the annular direction;

[0018] After the cutting is completed, the surface displacement information collected by the multiple cameras is corrected based on the three-dimensional digital image correlation technology to obtain accurate displacement information.

[0019] Compared with the prior art, the present invention has achieved the following technical effects:

[0020] 1) The present invention can realize the visualization of large deformation failure of soil samples under certain stress states. The annular laser surface emitted by the annular laser transmitter can form a high-brightness speckle field inside the sample for observation, which solves the limitation that the previous technology can only observe the failure process from the sample surface, that is, it can directly observe the large deformation shear failure process inside the sample.

[0021] 2) The transparent aggregate and pore liquid have the same refractive index, which is 1.458; the inner wall, outer wall and bottom plate are made of acrylic or tempered glass, which facilitates the plane transmission of the laser into the transparent sample while having greater anti-deformation ability.

[0022] 3) The equipment provided by the present invention can not only perform shear tests on transparent soil samples, but also perform shear tests on rock-soil interfaces and concrete-soil interfaces, and can further consider the influence of factors such as the morphology of the rock and concrete interfaces.

[0023] 4) For saturated soil, the fully transparent rock and soil shear tester obtains the deformation results of the soil by measuring the particle displacement of the high-brightness speckle field; it can also be extended to unsaturated soil to obtain the deformation results of the soil by quantifying transparency and other methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is the overall structure diagram of the fully transparent rock and soil annular shear test instrument;

[0026] Figure 2 for Figure 1 sectional view of

[0027] Figure 3 is a schematic diagram of a transparent annular shear box;

[0028] Figure 4 is a schematic diagram of the base;

[0029] Figure 5 is a schematic diagram of a twist cover;

[0030] Figure 6 for Figure 5 Schematic diagram of the tooth structure on the bottom gasket;

[0031] In the figure: 1-transparent annular shear box; 2-transparent sample; 3-base; 4-loading system; 5-imaging system; 7-pad; 8-air vent; 10-torsion cover; 11-belt; 12-toothed structure; 13-annular laser surface; 14-high-brightness speckle field; 15-bolt; 101-annular inner wall; 102-annular outer wall; 103-bottom plate; 104-cover body; 301-boss; 302-column; 401-axial actuator; 402-torsion actuator; 403-top plate; 404-force transmission rod; 501-annular laser emitter; 502-camera. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1

[0035] The present invention provides a fully transparent rock and soil annular shear test instrument, such as Figure 1 to Figure 6 As shown, it includes: a transparent annular shear box 1, a loading system 4 and an imaging system 5; the transparent annular shear box 1 is constructed with an inner cavity with an annular cross-section, specifically a circular annular cross-section, the inner cavity is used to accommodate a transparent sample 2, the bottom wall of the inner cavity is made of transparent material, and the annular inner wall 101 or the annular outer wall 102 of the inner cavity is made of transparent material; the imaging system 5 includes an annular laser emitter 501 and multiple cameras 502; the annular laser emitter 501 is arranged below the inner cavity and can emit laser from the bottom wall of the inner cavity into the inner cavity, the multiple cameras 502 are arranged outside the inner cavity, and the cameras 502 can capture image information in the inner cavity through the annular inner wall 101 or the annular outer wall 102; the loading system 4 is constructed to shear the sample in the inner cavity along the annular direction.

[0036] The present invention can realize the visualization of large deformation failure of soil samples under certain stress states. The annular laser surface 13 emitted by the annular laser emitter 501 can form a high-brightness speckle field 14 inside the sample for observation, which solves the limitation of the previous technology that the failure process can only be observed from the surface of the sample, that is, the large deformation shear failure process inside the sample can be directly observed.

[0037] The transparent aggregate and pore liquid constituting the transparent sample in the present invention need to have the same refractive index.

[0038] Example 2

[0039] On the basis of Example 1, the embodiment of the present invention further includes a base 3, a boss 301 is constructed on the top of the base 3, a transparent annular shear box 1 is detachably arranged on the top of the boss 301, a ring laser emitter 501 is fixedly mounted outside the boss 301, and the ring laser emitter 501 emits a ring laser vertically upward.

[0040] This embodiment facilitates the installation of the ring laser emitter 501 .

[0041] Example 3

[0042] On the basis of Example 2, the loading system 4 includes an axial actuator 401, a torsional actuator 402, a force transmission rod 404 and a torsional cover 10; the bottom of the force transmission rod 404 and the torsional cover 10 are detachably connected, and the bottom structure of the torsional cover 10 is constructed as an annular structure with the same size and shape as the inner cavity. In the initial state, the torsional cover 10 is located directly above the inner cavity, and a plurality of tooth structures 12 are provided on the bottom surface of the annular structure. The axial actuator 401 is constructed to drive the force transmission rod 404 to drive the torsional cover 10 to move up and down, and the torsional actuator 402 is constructed to drive the force transmission rod 404 to drive the torsional cover 10 to rotate, and the tooth structure 12 extends radially along the annular structure.

[0043] This embodiment uses an axial actuator 401 to drive the twist cover 10 to move down to press against the top of the transparent sample 2. After the twist cover 10 is pressed against the transparent sample 2, the twist actuator 402 drives the twist cover 10 to rotate to drive the upper transparent sample 2 to perform circumferential shear relative to the lower transparent sample 2.

[0044] The toothed structure 12 in this embodiment is to increase the coupling degree between the twist cover 10 and the transparent sample 2, thereby achieving a better shearing effect.

[0045] Example 4

[0046] On the basis of Example 3, two opposite and vertically arranged columns 302 are fixedly provided on the base 3, and a top plate 403 is fixedly provided on the top of the two columns 302. The axial actuator 401 and the torsional actuator 402 are fixedly provided on the top plate 403. The force transmission rod 404 is vertically arranged. The force transmission rod 404 includes a rod head and a rod body. The rod head and the rod body are rotatably connected around a vertical axis, and can be specifically connected through bearings. When bearings are used, one of the structures is connected to the outer ring of the bearing, and the other structure is connected to the inner ring of the bearing. An axial hole can also be provided on one of the structures, and a rotating shaft can be constructed on the other structure, and then the rotating shaft is inserted into the axial hole to realize the rotational connection between the two. The axial actuator 401 is transmission-connected to the rod head and drives the rod head to move up and down, and the torsional actuator 402 is transmission-connected to the rod body and drives the rod body to rotate around the vertical axis.

[0047] The two columns 302 and the top plate 403 in this embodiment can be regarded as a small gantry, which is used to support the loading system 4 .

[0048] Preferably, the torsion actuator 402 is a torsion motor, which drives the rod body to rotate through the belt 11 and the pulley. The axial actuator 401 can be a linear motor, an electric push rod, a cylinder, a hydraulic cylinder, etc.

[0049] Example 5

[0050] Based on Example 2, the transparent annular shear box 1 includes an annular inner wall 101, an annular outer wall 102 and a bottom plate 103. The annular inner wall 101 and the annular outer wall 102 are vertically fixed on the bottom plate 103. The bottom wall of the inner cavity is formed on the bottom plate 103. The bottom plate 103 is detachably arranged on the boss 301. The camera 502 is fixed on the bottom plate 103 outside the annular outer wall 102.

[0051] The bottom plate 103 in this embodiment not only serves as the bottom wall of the inner cavity, but is also used to support the camera 502 .

[0052] In a specific embodiment, bolt through holes are provided on the bottom plate 103 , threaded holes are provided on the top of the boss 301 , and the bottom plate 103 is fixed to the top of the boss 301 by bolts 15 .

[0053] Example 6

[0054] On the basis of Example 5, the annular inner wall 101, the annular outer wall 102 and the bottom plate 103 are made of transparent acrylic or tempered glass.

[0055] Example 7

[0056] On the basis of Example 1, the ring laser emitter 501 emits a ring laser curved surface 13 from bottom to top; the ring laser curved surface 13 passes through the bottom wall of the inner cavity and enters the transparent sample 2 to form a highlight speckle field 14; the shooting focus axes of the multiple cameras 502 coincide with the normal direction of the highlight speckle field 14.

[0057] Example 8

[0058] On the basis of Example 3, the twist cover 10 includes a cover body 104 and an annular pad 7 fixedly arranged on the bottom edge of the cover body 104, and the annular pad 7 is made of metal or cement mortar blocks.

[0059] Example 9

[0060] On the basis of the third embodiment, a vent hole 8 is provided on the twist cover 10 , and a pressure sensor and a torque sensor are provided in the boss 301 .

[0061] In this embodiment, when the twist cover 10 is pressed down, the air holes 8 are used to balance the air pressure inside and outside the twist cover 10 so that the twist cover 10 can move down smoothly.

[0062] The pressure sensor and torque sensor in the boss 301 are used to detect the pressure and torque on the boss 301 and convert them into the pressure and torque on the sample, so as to monitor the pressure and torque on the sample in real time during the test.

[0063] Example 10

[0064] On the basis of the above embodiments, the present invention further provides a method for using a fully transparent rock and soil annular shear test instrument, comprising:

[0065] A transparent sample 2 is prepared in the inner cavity.

[0066] The ring laser emitter 501 and the multiple cameras 502 are turned on, and all other light sources in the environment are turned off. The exposure and focus of the multiple cameras 502 are adjusted to make the highlight speckle field 14 clearly visible.

[0067] The loading system 4 shears the sample in the inner cavity along the annular direction.

[0068] After the cutting is completed, the surface displacement information collected by the multiple cameras 502 is corrected based on the three-dimensional digital image correlation technology to obtain accurate displacement information.

[0069] This embodiment has all the advantages of the above embodiments, which will not be described in detail here.

[0070] The specific steps include:

[0071] 1) Prepare a transparent sample 2 in a transparent annular shear box 1. For non-cohesive soil, first pour pore liquid into the transparent annular shear box 1, and then sprinkle fused quartz particles using the sand rain method, and tap the side of the transparent annular shear box 1 to expel bubbles during the process; for cohesive soil, mix amorphous silica or fumed silica with sufficient pore liquid in advance, and then fill the transparent annular shear box 1, and place the transparent annular shear box 1 in a vacuum box for vacuum saturation treatment until the sample is completely transparent.

[0072] 2) Adjust the axial actuator 401 so that the force transmission rod 404 rises to the maximum limit; then place the transparent annular shear box 1 on the boss 301 and tighten it with bolts 15.

[0073] 3) Gently place the cover body 104 with the cushion block 7 installed on the transparent annular shear box 1, and control the axial actuator 401 to make the force transmission rod 404 descend, so that the force transmission rod 404 contacts and fixes the cover body 104.

[0074] 4) Turn on the ring laser emitter 501 and the multiple cameras 502, turn off all other light sources in the environment, and adjust the exposure and focus of the multiple cameras 502 to make the highlight speckle field 14 clearly visible.

[0075] 5) Adjust the axial actuator 401 to apply vertical consolidation pressure downward; after reaching the preset consolidation time, adjust the torsion actuator 402 to apply torsion torque to the cover 104; multiple cameras 502 simultaneously capture the deformation data of the transparent rock and soil sample at different angles.

[0076] 6) After the cutting is completed, the surface displacement information collected by the multiple cameras 502 is corrected based on the three-dimensional digital image correlation technology DIC to obtain accurate displacement information.

[0077] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A fully transparent rock and soil annular shear test instrument, characterized by: include: A transparent annular shear box, a loading system and an imaging system; the transparent annular shear box is provided with an inner cavity with an annular cross-section, the inner cavity is used to accommodate a transparent sample, the bottom wall of the inner cavity is made of a transparent material, and the annular inner wall or the annular outer wall of the inner cavity is also made of a transparent material; the imaging system comprises an annular laser emitter and a plurality of cameras; the annular laser emitter is arranged below the inner cavity and can emit laser from the bottom wall of the inner cavity into the inner cavity, the plurality of cameras are arranged outside the inner cavity, and the cameras can capture image information in the inner cavity through the annular inner wall or the annular outer wall; the loading system is constructed to shear the transparent sample in the inner cavity along the annular direction.

2. The fully transparent rock and soil circumferential shear test instrument according to claim 1 is characterized in that: It also includes a base, the top of the base is constructed with a boss, the transparent annular shear box is detachably arranged on the top of the boss, the annular laser emitter is sleeved and fixed outside the boss, and the annular laser emitter emits annular laser vertically upward.

3. The fully transparent rock and soil circumferential shear test instrument according to claim 2 is characterized in that: The loading system includes an axial actuator, a torsional actuator, a force transmission rod and a torsional cover; the bottom of the force transmission rod and the torsional cover are detachably connected, the bottom structure of the torsional cover is constructed as an annular structure with the same size and shape as the inner cavity, in an initial state, the torsional cover is located directly above the inner cavity, and a plurality of tooth structures are provided on the bottom surface of the annular structure, the axial actuator is constructed to drive the force transmission rod to drive the torsional cover to move up and down, the torsional actuator is constructed to drive the force transmission rod to drive the torsional cover to rotate, and the tooth structure extends radially along the annular structure.

4. The fully transparent rock and soil circumferential shear test instrument according to claim 3 is characterized in that: Two opposite and vertically arranged columns are fixedly arranged on the base, and a top plate is fixedly arranged on the top of the two columns. The axial actuator and the torsional actuator are fixedly arranged on the top plate. The force transmission rod is vertically arranged, and the force transmission rod includes a rod head and a rod body. The rod head and the rod body are rotatably connected around a vertical axis. The axial actuator is transmission-connected to the rod head and drives the rod head to move up and down, and the torsional actuator is transmission-connected to the rod body and drives the rod body to rotate around the vertical axis.

5. The fully transparent rock and soil annular shear test instrument according to claim 2 is characterized by: The transparent annular shear box includes the annular inner wall, the annular outer wall and the bottom plate. The annular inner wall and the annular outer wall are vertically fixed on the bottom plate. The bottom wall of the inner cavity is formed on the bottom plate. The bottom plate is detachably arranged on the boss. The camera is fixedly arranged on the bottom plate outside the annular outer wall.

6. The fully transparent rock and soil annular shear test instrument according to claim 5 is characterized by: The annular inner wall, the annular outer wall and the bottom plate are made of transparent acrylic or tempered glass.

7. The fully transparent rock and soil annular shear test instrument according to claim 2 is characterized by: The annular laser emitter emits an annular laser curved surface from bottom to top; the annular laser curved surface passes through the bottom wall of the inner cavity and enters the transparent sample to form a high-brightness speckle field; the shooting focus axes of the multiple cameras coincide with the normal direction of the high-brightness speckle field.

8. The fully transparent rock and soil annular shear test instrument according to claim 3 is characterized by: The twist cover comprises a cover body and an annular pad fixedly arranged on the bottom edge of the cover body, and the annular pad is made of metal material or cement mortar block.

9. The fully transparent rock and soil annular shear test instrument according to claim 3 is characterized by: The twist cover is provided with a vent hole, and the boss is provided with a pressure sensor and a torque sensor.

10. A method for using the fully transparent rock and soil annular shear test instrument according to any one of claims 1 to 9, characterized in that: include: preparing a transparent specimen in the inner cavity; Turn on the ring laser transmitter and multiple cameras, turn off all other light sources in the environment, and adjust the exposure and focus of multiple cameras to make the bright speckle field clearly visible; The loading system shears the sample in the inner cavity along the annular direction; After the cutting is completed, the surface displacement information collected by the multiple cameras is corrected based on the three-dimensional digital image correlation technology to obtain accurate displacement information.

Images