A Four-Camera Transparent Soil Three-Dimensional Deformation Measurement Device and Its Usage Method

Abstract

The present invention discloses a four-camera transparent soil three-dimensional deformation measurement device and its usage method. The device includes an optical platform, as well as a loading system, two laser systems, four camera systems, and a computer, all of which are installed on the optical platform. The four camera systems are respectively located on the four sides of the loading system, and the two laser systems are respectively located on two adjacent sides of the loading system. The loading system and the camera systems are both equipped with horizontal and vertical moving platforms to adjust the positions of the lasers or cameras. During operation, a transparent soil specimen is placed on the loading platform, the positions of the two lasers and the four cameras are adjusted, the servo actuator is started for loading, and the computer controls the opening, closing, and movement of each laser and camera to complete the shooting of the speckle cross-section of the transparent soil specimen. The device is simple to operate, convenient to use, highly automated, highly accurate, and has good detachable flexibility. It can be used for the measurement of three-dimensional and two-dimensional deformations of soil in transparent soil model tests, improving the test efficiency and measurement level.

Description

Technical Field

[0001] The present invention relates to the technical field of transparent soil model tests, and particularly relates to a four-camera transparent soil three-dimensional deformation measurement device and a using method thereof. Background Art

[0002] In the field of geotechnical engineering, the method of using artificially synthesized transparent soil to simulate natural soil to study problems such as internal deformation, displacement, and seepage of soil has gradually been recognized and applied by engineering technicians. The transparent soil experimental technology avoids the deficiencies of intrusive measurement in traditional geotechnical experiments, and non-destructively and continuously measures parameters such as internal deformation, displacement, and seepage of soil through a visualization method, which is more intuitive, accurate, and easy to operate.

[0003] In transparent soil model tests, due to the limitations of test device conditions, generally only the cross-section of the soil in one direction (x-y plane) is observed. This method can only obtain the two-dimensional horizontal (x-axis direction) and vertical (y-axis direction) displacements of the soil plane, while for the displacement in the third direction (z-axis direction) of the soil, the traditional method cannot obtain it, and the true deformation situation of the soil cannot be accurately monitored. Summary of the Invention

[0004] The purpose of the present invention is to provide a four-camera transparent soil three-dimensional deformation measurement device and a using method thereof to solve the problems existing in the prior art.

[0005] The technical solution adopted to achieve the purpose of the present invention is as follows: a four-camera transparent soil three-dimensional deformation measurement device includes an optical platform, and a loading system, two laser systems, four camera systems, and a computer all installed on the optical platform.

[0006] The loading system includes a servo actuator, a loading rod, a reaction frame, and a loading platform. The reaction frame and the loading platform are both fixed on the horizontal optical platform. A horizontal rectangular plate is provided at the upper end of the reaction frame, the servo actuator is fixed on the rectangular plate, the servo actuator is connected to the loading rod, and the lower end of the loading rod passes through the rectangular plate and is located directly above the loading platform.

[0007] The two laser systems are respectively located on two adjacent sides of the rectangular plate. The laser system includes a laser, a vertical frame, a lifting slider, a rotating rod, and a stepping module III.

[0008] The two vertical frames of each laser system are arranged at intervals and the lower ends are both fixed on the optical platform. The distances from the two vertical frames to the rectangular plate are the same. A vertical chute is provided on each vertical frame, and two lifting sliders are respectively slidably connected in the chutes of the two vertical frames.

[0009] Both ends of the third stepping module are movably connected to two lifting sliders through horizontal rotating rods, and the laser is slidably connected to the third stepping module with the sliding direction being the same as the horizontal direction.

[0010] The four camera systems are respectively located at the four side edges of the rectangular plate. The camera system includes a camera, a first stepping module, a second stepping module, and a bottom plate. The bottom plate is fixed on the optical platform. The second stepping module is installed on the bottom plate. The lower end of the first stepping module is slidably connected to the second stepping module. The camera is slidably connected to the first stepping module. The sliding direction of the first stepping module on the second stepping module is the same as the horizontal direction, and the sliding direction of the camera on the first stepping module is vertical. In the laser system and the camera system located on the same side of the rectangular plate, the sliding direction of the laser on the third stepping module is perpendicular to the sliding direction of the first stepping module on the second stepping module.

[0011] During operation, the transparent soil specimen is placed on the loading platform, the positions of the two lasers and the four cameras are adjusted, the servo actuator is started for loading, and the computer controls the opening, closing, and movement of each laser and camera to complete the shooting of the speckle section of the transparent soil specimen.

[0012] Furthermore, the loading rod is vertically arranged, and a pressure sensor and a displacement sensor are connected to the lower end of the loading rod.

[0013] Furthermore, the second stepping module includes a module body II, a lead screw II, and a stepping motor II. The module body II is a horizontally arranged strip structure. Two bumps II are respectively connected to both ends of the module body II, and the bumps II protrude from the upper surface of the module body II. The lead screw II is horizontally arranged between the two bumps II, and the stepping motor II is installed in one bump II and connected to the lead screw II.

[0014] The first stepping module includes a module body I, a lead screw I, a sliding block I, and a stepping motor I. The module body I is a vertically arranged strip structure. Two bumps I are respectively connected to the upper and lower ends of the module body I and protrude from the same side of the module body I. The lead screw I is vertically arranged between the two bumps I, and the stepping motor I is installed in the upper bump I and connected to the lead screw I. A threaded through hole matching the lead screw II is provided on the bump I at the lower end of the module body I, and the bump I is installed on the lead screw II through its threaded through hole. A threaded through hole matching the lead screw I is provided on the sliding block I, and the sliding block I is installed on the lead screw I through its threaded through hole. The camera platform is fixed on the sliding block I, and the camera is hinged on the camera platform.

[0015] The stepping module III includes a module body III, a lead screw III, a sliding block III, and a stepping motor III. The module body III is a horizontally arranged strip structure. Two bumps III are respectively connected to both ends of the module body III, and the bumps III protrude from the same side of the module body III. The lead screw III is horizontally arranged between the two bumps III. The stepping motor III is installed in one bump III and connected to the lead screw III. Both bumps III are movably connected to the corresponding lifting sliders through rotating rods. A threaded through hole matching the lead screw III is provided on the sliding block III, and the sliding block III is installed on the lead screw III through its threaded through hole. The laser is fixedly connected to the sliding block III.

[0016] In the laser system and the camera system on the same side of the rectangular plate, the lead screw II is perpendicular to the lead screw III.

[0017] The usage method of the above four-camera transparent soil three-dimensional deformation measurement device includes the following steps:

[0018] 1) Install the measurement device, place the prepared transparent soil specimen on the loading platform, adjust the relative position between the transparent soil specimen and the loading rod according to the test requirements, turn on the laser, and adjust the positions of each camera and the laser to ensure that the axis of the camera lens is perpendicular to the sheet laser plane. The initial positions of the irradiation surfaces of the two lasers are located at the middle section of the soil body.

[0019] 2) Taking the servo actuator as the center, sort the two lasers and the four cameras in the counterclockwise direction. The two lasers are respectively denoted as laser I and laser II, and the four cameras are respectively denoted as camera I, camera II, camera III, and camera IV. Laser I and camera I are on the same side of the rectangular plate, and laser II and camera II are on the same side of the rectangular plate.

[0020] 3) Start the servo actuator for loading. The computer controls laser I to turn on and laser II to turn off, and camera IV takes a picture of the speckle section formed in the soil body at the initial position of laser I.

[0021] 4) The computer controls laser I to move horizontally in the direction close to the camera system where camera IV is located. Camera IV moves synchronously and takes pictures at intervals. After the laser plane moves out of the transparent soil specimen, adjust laser I and camera IV to the initial positions. The computer controls laser I to move horizontally in the direction close to the camera system where camera II is located. Camera II moves synchronously and takes pictures at intervals. After the laser plane emitted by laser I moves out of the transparent soil specimen again, adjust laser I and camera II to the initial positions.

[0022] 5) The computer controls laser I to turn off and laser II to turn on, and camera I takes a picture of the speckle section formed in the soil body at the initial position of laser II.

[0023] 6) The computer-controlled laser II moves horizontally towards the camera system where Camera I is located. Camera I moves synchronously and takes pictures at intervals. After the laser plane emitted by the laser II moves out of the transparent soil specimen, the laser II and Camera I are adjusted to the initial positions. Then, the computer controls the laser II to move horizontally towards the camera system where Camera III is located. Camera III moves synchronously and takes pictures at intervals. After the laser plane emitted by the laser II moves out of the transparent soil specimen again, the laser II and Camera III are adjusted to the initial positions, and then the laser II is turned off.

[0024] 7) Change the load of the servo actuator according to requirements, and repeat steps 3) - 6) to conduct the next-stage soil speckle cross-section shooting until the loading is completed.

[0025] 8) Use PIV / DIC image processing software for image post-processing.

[0026] 9) Use MATLAB software to perform interpolation and three-dimensional reconstruction processing on the slice displacement data obtained in step 8) to obtain the three-dimensional displacement of the entire soil mass.

[0027] The technical effects of the present invention are beyond doubt. The present invention designs a four-camera and two-laser system device. By using two vertically intersecting laser planes in cooperation with two cameras perpendicular to them, the movement of the cameras and lasers is precisely controlled through a stepping device, thereby obtaining the displacements in three directions (x, y, and z-axis directions) of different cross-sections inside the soil mass. The three-dimensional displacement deformation of the entire soil mass is obtained by using the MATLAB three-dimensional reconstruction program. The device can improve the size of the transparent soil model tank by using four cameras for shooting, and expand the application range of the transparent soil model test. The three-dimensional displacement deformation of the soil mass can be obtained by using the vertically intersecting lasers. The device is simple to operate, convenient to use, highly automated, highly accurate, and has good detachable flexibility. It can be applied to the measurement of three-dimensional and two-dimensional deformations of the soil mass in the transparent soil model test, improving the test efficiency and measurement level. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the overall structure of the four-camera transparent soil three-dimensional deformation measurement device;

[0029] Figure 2 It is a schematic diagram of the overall structure of the loading system;

[0030] Figure 3 It is a schematic diagram of the overall structure of the laser system;

[0031] Figure 4 It is a schematic diagram of the overall structure of the camera system.

[0032] In the figure: loading system 1, servo actuator 101, loading rod 102, reaction frame 103, rectangular plate 1031, loading platform 104, laser system 2, laser 201, vertical frame 202, lifting slider 203, rotating rod 204, stepping module III 205, camera system 3, camera 301, stepping module I 302, stepping module II 303, bottom plate 304, computer 4, and optical platform 5. Detailed implementation mode

[0033] The present invention will be further described below in conjunction with embodiments, but it should not be understood that the above-mentioned subject matter scope of the present invention is limited to the following embodiments. Without departing from the above-mentioned technical idea of the present invention, various substitutions and changes made according to common general knowledge and conventional means in the art shall be included within the protection scope of the present invention.

[0034] Embodiment 1:

[0035] See Figure 1 , this embodiment discloses a four-camera transparent soil three-dimensional deformation measurement device, which is arranged in a rectangular coordinate system o-xyz and includes an optical platform 5, a loading system 1, two laser systems 2, four camera systems 3, and a computer 4, all of which are installed on the optical platform 5.

[0036] See Figure 2 , the loading system 1 includes a servo actuator 101, a loading rod 102, a reaction frame 103, and a loading platform 104. The reaction frame 103 and the loading platform 104 are both fixed on the horizontal optical platform 5. A horizontal rectangular plate 1031 is provided at the upper end of the reaction frame 103. The servo actuator 101 is fixed on the rectangular plate 1031. The servo actuator 101 is connected to the loading rod 102. The lower end of the loading rod 102 passes through the rectangular plate 1031 and is located directly above the loading platform 104. The loading rod 102 is vertically arranged, and a pressure sensor and a displacement sensor are connected to the lower end of the loading rod 102.

[0037] The two laser systems 2 are respectively located on two adjacent sides of the rectangular plate 1031. The laser system 2 includes a laser 201, a vertical frame 202, a lifting slider 203, a rotating rod 204, and a stepping module III 205.

[0038] The two vertical frames 202 of each laser system 2 are arranged at intervals and the lower ends are both fixed on the optical platform 5. The distances from the two vertical frames 202 to the rectangular plate 1031 are the same. Vertical sliding grooves are provided on each vertical frame 202, and two lifting sliders 203 are respectively slidably connected in the sliding grooves of the two vertical frames 202.

[0039] See Figure 3, both ends of the third stepping module 205 are movably connected to two lifting sliders 203 through horizontal rotating rods 204. The laser 201 is slidably connected to the third stepping module 205 and the sliding direction is consistent with the horizontal direction. The adjustment of the laser irradiation angle can be realized by rotating the rotating rod 204.

[0040] The four camera systems 3 are respectively located at the four side edges of the rectangular plate 1031. Refer to Figure 4 , the camera system 3 includes a camera 301, a first stepping module 302, a second stepping module 303 and a bottom plate 304. The bottom plate 304 is fixed on the optical platform 5. The second stepping module 303 is installed on the bottom plate 304. The lower end of the first stepping module 302 is slidably connected to the second stepping module 303. The camera 301 is slidably connected to the first stepping module 302. The sliding direction of the first stepping module 302 on the second stepping module 303 is consistent with the horizontal direction, and the sliding direction of the camera 301 on the first stepping module 302 is vertical. Among the laser system 2 and the camera system 3 on the same side of the rectangular plate 1031, the sliding direction of the laser 201 on the third stepping module 205 is perpendicular to the sliding direction of the first stepping module 302 on the second stepping module 303.

[0041] The second stepping module 303 includes a module body II, a lead screw II and a stepping motor II. The module body II is a horizontally arranged strip structure. Two bumps II are respectively connected to both ends of the module body II, and the bumps II protrude from the upper surface of the module body II. The lead screw II is horizontally arranged between the two bumps II, and the stepping motor II is installed in one bump II and connected to the lead screw II.

[0042] The first stepping module 302 includes a module body I, a lead screw I, a sliding block I and a stepping motor I. The module body I is a vertically arranged strip structure. Two bumps I are respectively connected to the upper and lower ends of the module body I and protrude from the same side of the module body I. The lead screw I is vertically arranged between the two bumps I, and the stepping motor I is installed in the upper bump I and connected to the lead screw I. A threaded through hole matching the lead screw II is provided on the bump I at the lower end of the module body I, and the bump I is installed on the lead screw II through its threaded through hole. A threaded through hole matching the lead screw I is provided on the sliding block I, and the sliding block I is installed on the lead screw I through its threaded through hole. The camera platform is fixed on the sliding block I, and the camera 301 is hinged on the camera platform.

[0043] The stepping module III 205 includes a module body III, a lead screw III, a sliding block III, and a stepping motor III. The module body III is a horizontally arranged strip structure. Two bumps III are respectively connected to both ends of the module body III, and the bumps III extend from the same side of the module body III. The lead screw III is horizontally arranged between the two bumps III. The stepping motor III is installed in one bump III and connected to the lead screw III. Both bumps III are movably connected to the corresponding lifting slider 203 through a rotating rod 204. A threaded through hole matching the lead screw III is provided on the sliding block III, and the sliding block III is installed on the lead screw III through its threaded through hole. The laser 201 is fixedly connected to the sliding block III.

[0044] In the laser system 2 and the camera system 3 on the same side of the rectangular plate 1031, the lead screw II is perpendicular to the lead screw III.

[0045] During operation, place the transparent soil specimen on the loading platform 104, adjust the positions of the two lasers 201 and the four cameras 301, start the servo actuator 101 for loading, and the computer 4 controls the opening and closing and movement of each laser 201 and camera 301 to complete the shooting of the speckle section of the transparent soil specimen.

[0046] It should be noted that a four-camera two-laser system device disclosed in this embodiment uses two vertically intersecting laser planes in cooperation with two cameras perpendicular thereto, and precisely controls the movement of the cameras and lasers through a stepping device, so as to obtain the displacements in three directions (x, y, z-axis directions) of different sections inside the soil body, and use the MATLAB three-dimensional reconstruction program to obtain the three-dimensional displacement deformation of the entire soil body. This device is mainly made of aluminum and stainless steel materials. This device can improve the size of the transparent soil model tank by using four cameras for shooting, and improve the application range of the transparent soil model test. The three-dimensional displacement deformation of the soil body can be obtained by using vertically intersecting lasers. This device is simple to operate, convenient to use, has a high degree of automation, high precision, and good detachable flexibility. It can be applied to the measurement of three-dimensional and two-dimensional deformations of the soil body in the transparent soil model test, improving the test efficiency and measurement level.

[0047] Embodiment 2:

[0048] This embodiment discloses a usage method of the four-camera transparent soil three-dimensional deformation measurement device described in Embodiment 1, including the following steps:

[0049] 1) Install the measurement device, place the prepared transparent soil specimen on the loading platform, adjust the relative position between the transparent soil specimen and the loading rod 102 according to the test requirements, turn on the laser 201, adjust the positions of each camera 301 and the laser 201, and ensure that the axis of the camera 301 lens is perpendicular to the sheet laser plane. The initial positions of the irradiation surfaces of the two lasers 201 are located at the middle section of the soil body.

[0050] 2) Sort the two lasers 201 and the four cameras 301 counterclockwise with the servo actuator 101 as the center. The two lasers 201 are respectively denoted as Laser I and Laser II, and the four cameras 301 are respectively denoted as Camera I, Camera II, Camera III, and Camera IV. Laser I and Camera I are on the same side of the rectangular plate 1031, and Laser II and Camera II are on the same side of the rectangular plate 1031.

[0051] 3) Start the servo actuator 101 for loading. The computer 4 controls Laser I to turn on and Laser II to turn off, and Camera IV takes pictures of the speckle section formed in the soil mass at the initial position of Laser I.

[0052] 4) The computer 4 controls Laser I to move horizontally towards the camera system 3 where Camera IV is located. Camera IV moves synchronously and takes pictures at intervals. After the laser plane moves out of the transparent soil specimen, adjust Laser I and Camera IV to the initial position. The computer 4 controls Laser I to move horizontally towards the camera system 3 where Camera II is located. Camera II moves synchronously and takes pictures at intervals. After the laser plane emitted by Laser I moves out of the transparent soil specimen again, adjust Laser I and Camera II to the initial position.

[0053] 5) The computer 4 controls Laser I to turn off and Laser II to turn on, and Camera I takes pictures of the speckle section formed in the soil mass at the initial position of Laser II.

[0054] 6) The computer 4 controls Laser II to move horizontally towards the camera system 3 where Camera I is located. Camera I moves synchronously and takes pictures at intervals. After the laser plane emitted by Laser II moves out of the transparent soil specimen, adjust Laser II and Camera I to the initial position. The computer 4 controls Laser II to move horizontally towards the camera system 3 where Camera III is located. Camera III moves synchronously and takes pictures at intervals. After the laser plane emitted by Laser II moves out of the transparent soil specimen again, adjust Laser II and Camera III to the initial position, and turn off Laser II.

[0055] 7) Change the load of the servo actuator 101 according to requirements, and repeat steps 3) - 6) to conduct the next-stage soil mass speckle section photography until the loading ends.

[0056] 8) Use PIV / DIC image processing software for image post-processing. Among them, the horizontal displacement u 1 and the vertical displacement v 1 are obtained from the image processing of the pictures taken by Camera II and Camera IV, and the horizontal displacement denoted as w 2 and the vertical displacement v 2 are obtained from the image processing of the pictures taken by Camera I and Camera III.

[0057] 9) Use MATLAB software to perform interpolation and three-dimensional reconstruction on the slice displacement data obtained in step 8) to obtain the three-dimensional displacement of the entire soil mass; among them, the horizontal displacement (displacement in the x-axis direction) u of the entire soil mass is obtained by interpolating u 1 through interpolation, where the vertical displacement v (displacement in the y-axis direction) of the entire soil mass is obtained by v 1 and v 2 through interpolation, and the out-of-plane displacement (displacement in the z-axis direction) w of the entire soil mass is obtained by interpolating w 2 through interpolation.

[0058] Example 3:

[0059] See Figure 1 , this example discloses a four-camera transparent soil three-dimensional deformation measurement device, which includes an optical platform 5 and a loading system 1, two laser systems 2, four camera systems 3 and a computer 4 that are all installed on the optical platform 5.

[0060] See Figure 2 , the loading system 1 includes a servo actuator 101, a loading rod 102, a reaction frame 103 and a loading platform 104. The reaction frame 103 and the loading platform 104 are both fixed on the horizontal optical platform 5. A horizontal rectangular plate 1031 is provided at the upper end of the reaction frame 103. The servo actuator 101 is fixed on the rectangular plate 1031. The servo actuator 101 is connected to the loading rod 102. The lower end of the loading rod 102 passes through the rectangular plate 1031 and is located directly above the loading platform 104.

[0061] The two laser systems 2 are respectively located on two adjacent sides of the rectangular plate 1031. The laser system 2 includes a laser 201, a vertical frame 202, a lifting slider 203, a rotating rod 204 and a stepping module III 205.

[0062] The two vertical frames 202 of each laser system 2 are arranged at intervals and the lower ends are both fixed on the optical platform 5. The distances from the two vertical frames 202 to the rectangular plate 1031 are the same. Vertical chutes are provided on each vertical frame 202. Two lifting sliders 203 are respectively slidably connected in the chutes of the two vertical frames 202.

[0063] See Figure 3 , the two ends of the stepping module III 205 are movably connected to the two lifting sliders 203 through a horizontal rotating rod 204. The laser 201 is slidably connected to the stepping module III 205 and the sliding direction is the same as the horizontal direction.

[0064] The four camera systems 3 are respectively located at the four side edges of the rectangular plate 1031. See Figure 4, the camera system 3 includes a camera 301, a stepping module I 302, a stepping module II 303, and a base plate 304. The base plate 304 is fixed on the optical platform 5. The stepping module II 303 is installed on the base plate 304. The lower end of the stepping module I 302 is slidably connected to the stepping module II 303. The camera 301 is slidably connected to the stepping module I 302. The sliding direction of the stepping module I 302 on the stepping module II 303 is consistent with the horizontal direction, and the sliding direction of the camera 301 on the stepping module I 302 is vertical. In the laser system 2 and the camera system 3 on the same side of the rectangular plate 1031, the sliding direction of the laser 201 on the stepping module III 205 is perpendicular to the sliding direction of the stepping module I 302 on the stepping module II 303.

[0065] During operation, place the transparent soil specimen on the loading platform 104, adjust the positions of the two lasers 201 and the four cameras 301, start the servo actuator 101 for loading, and the computer 4 controls the opening, closing, and movement of each laser 201 and camera 301 to complete the shooting of the speckle section of the transparent soil specimen.

[0066] Embodiment 4:

[0067] The main structure of this embodiment is the same as that of Embodiment 3. Further, the loading rod 102 is vertically arranged, and a pressure sensor and a displacement sensor are connected to the lower end of the loading rod 102.

[0068] Embodiment 5:

[0069] The main structure of this embodiment is the same as that of Embodiment 3. Further, the stepping module II 303 includes a module body II, a lead screw II, and a stepping motor II. The module body II is a horizontally arranged strip-shaped structure. Two bumps II are respectively connected to both ends of the module body II, and the bumps II protrude from the upper surface of the module body II. The lead screw II is horizontally arranged between the two bumps II, and the stepping motor II is installed in one bump II and connected to the lead screw II.

[0070] The stepping module I 302 includes a module body I, a lead screw I, a sliding block I, and a stepping motor I. The module body I is a vertically arranged strip-shaped structure. Two bumps I are respectively connected to the upper and lower ends of the module body I and protrude from the same side of the module body I. The lead screw I is vertically arranged between the two bumps I, and the stepping motor I is installed in the upper bump I and connected to the lead screw I. A threaded through hole matching the lead screw II is opened on the bump I at the lower end of the module body I, and the bump I is installed on the lead screw II through its threaded through hole. A threaded through hole matching the lead screw I is opened on the sliding block I, and the sliding block I is installed on the lead screw I through its threaded through hole. The camera platform is fixed on the sliding block I, and the camera 301 is hinged on the camera platform.

[0071] The stepping module III 205 includes a module body III, a lead screw III, a sliding block III, and a stepping motor III. The module body III is a horizontally arranged strip-shaped structure. Two bumps III are respectively connected to both ends of the module body III, and the bumps III extend out of the same side of the module body III. The lead screw III is horizontally arranged between the two bumps III. The stepping motor III is installed in one bump III and connected to the lead screw III. Both bumps III are movably connected to the corresponding lifting slider 203 through a rotating rod 204. A threaded through hole matching the lead screw III is provided on the sliding block III, and the sliding block III is installed on the lead screw III through its threaded through hole. The laser 201 is fixedly connected to the sliding block III. Among the laser system 2 and the camera system 3 on the same side of the rectangular plate 1031, the lead screw II is perpendicular to the lead screw III.

Claims

1. A three-dimensional deformation measurement device for four-camera transparent soil, characterized in that: it includes an optical platform (5), as well as a loading system (1), two laser systems (2), four camera systems (3) and a computer (4) all installed on the optical platform (5); The loading system (1) includes a servo actuator (101), a loading rod (102), a reaction frame (103) and a loading platform (104). The reaction frame (103) and the loading platform (104) are both fixed on the horizontal optical platform (5). A horizontal rectangular plate (1031) is provided at the upper end of the reaction frame (103). The servo actuator (101) is fixed on the rectangular plate (1031). The servo actuator (101) is connected to the loading rod (102). The lower end of the loading rod (102) passes through the rectangular plate (1031) and is located directly above the loading platform (104); The two laser systems (2) are respectively located on two adjacent sides of the rectangular plate (1031). The laser system (2) includes a laser (201), a vertical frame (202), a lifting slider (203), a rotating rod (204) and a stepping module III (205); For each of the two laser systems (2), the two vertical frames (202) are arranged at intervals and their lower ends are both fixed on the optical platform (5). The distances from the two vertical frames (202) to the rectangular plate (1031) are the same. A vertical chute is provided on each vertical frame (202). The two lifting sliders (203) are respectively slidably connected in the chutes of the two vertical frames (202); The two ends of the stepping module III (205) are movably connected to the two lifting sliders (203) through a horizontal rotating rod (204). The laser (201) is slidably connected to the stepping module III (205) and the sliding direction is the same as the horizontal direction; The four camera systems (3) are respectively located at the four side edges of the rectangular plate (1031). The camera system (3) includes a camera (301), a stepping module I (302), a stepping module II (303) and a bottom plate (304). The bottom plate (304) is fixed on the optical platform (5). The stepping module II (303) is installed on the bottom plate (304). The lower end of the stepping module I (302) is slidably connected to the stepping module II (303). The camera (301) is slidably connected to the stepping module I (302). The sliding direction of the stepping module I (302) on the stepping module II (303) is the same as the horizontal direction. The sliding direction of the camera (301) on the stepping module I (302) is vertical; In the laser system (2) and the camera system (3) located on the same side of the rectangular plate (1031), the sliding direction of the laser (201) on the stepping module III (205) is perpendicular to the sliding direction of the stepping module I (302) on the stepping module II (303); During operation, place the transparent soil specimen on the loading platform (104), adjust the positions of the two lasers (201) and the four cameras (301), start the servo actuator (101) to apply the load, and the computer (4) controls the opening, closing, and movement of each laser (201) and camera (301) to complete the shooting of the speckle section of the transparent soil specimen.

2. A four-camera transparent soil three-dimensional deformation measurement device according to claim 1, characterized in that: the loading rod (102) is vertically arranged, and a pressure sensor and a displacement sensor are connected to the lower end of the loading rod (102).

3. A four-camera transparent soil three-dimensional deformation measurement device according to claim 1, characterized in that: the stepping module II (303) includes a module body II, a lead screw II, and a stepping motor II. The module body II is a horizontally arranged strip structure. Two bumps II are respectively connected to both ends of the module body II, and the bumps II protrude from the upper surface of the module body II. The lead screw II is horizontally arranged between the two bumps II, and the stepping motor II is installed in one of the bumps II and connected to the lead screw II; the stepping module I (302) includes a module body I, a lead screw I, a sliding block I, and a stepping motor I. The module body I is a vertically arranged strip structure. Two bumps I are respectively connected to the upper and lower ends of the module body I and protrude from the same side of the module body I. The lead screw I is vertically arranged between the two bumps I, and the stepping motor I is installed in the upper bump I and connected to the lead screw I; A threaded through hole matching the lead screw II is opened on the bump I at the lower end of the module body I, and the bump I is installed on the lead screw II through its threaded through hole; A threaded through hole matching the lead screw I is opened on the sliding block I, and the sliding block I is installed on the lead screw I through its threaded through hole. The camera platform is fixed on the sliding block I, and the camera (301) is hinged on the camera platform; the stepping module III (205) includes a module body III, a lead screw III, a sliding block III, and a stepping motor III. The module body III is a horizontally arranged strip structure. Two bumps III are respectively connected to both ends of the module body III, and the bumps III protrude from the same side of the module body III. The lead screw III is horizontally arranged between the two bumps III, and the stepping motor III is installed in one of the bumps III and connected to the lead screw III. Both bumps III are movably connected to the corresponding lifting slider (203) through a rotating rod (204). A threaded through hole matching the lead screw III is opened on the sliding block III, and the sliding block III is installed on the lead screw III through its threaded through hole. The laser (201) is fixedly connected to the sliding block III; in the laser system (2) and the camera system (3) on the same side of the rectangular plate (1031), the lead screw II is perpendicular to the lead screw III.

4. A method for using the four-camera transparent soil three-dimensional deformation measurement device according to any one of claims 1 to 3, characterized in that it includes the following steps: 1) Install the measurement device, place the prepared transparent soil specimen on the loading platform, adjust the relative position between the transparent soil specimen and the loading rod (102) according to the test requirements, turn on the laser (201), and adjust the positions of each camera (301) and the laser (201) to ensure that the axis of the camera (301) lens is perpendicular to the plane of the sheet laser. The initial positions of the irradiation surfaces of the two lasers (201) are located at the mid-section of the soil body. 2) Taking the servo actuator (101) as the center, sort the two lasers (201) and the four cameras (301) in the counterclockwise direction. The two lasers (201) are respectively denoted as Laser I and Laser II, and the four cameras (301) are respectively denoted as Camera I, Camera II, Camera III, and Camera IV. Laser I and Camera I are on the same side of the rectangular plate (1031), and Laser II and Camera II are on the same side of the rectangular plate (1031). 3) Start the servo actuator (101) for loading. The computer (4) controls Laser I to turn on and Laser II to turn off, and Camera IV takes pictures of the speckle section formed in the soil body at the initial position of Laser I. 4) The computer (4) controls Laser I to move horizontally in the direction close to the camera system (3) where Camera IV is located. Camera IV moves synchronously and takes pictures at intervals. After the laser plane moves out of the transparent soil specimen, adjust Laser I and Camera IV to the initial positions. The computer (4) controls Laser I to move horizontally in the direction close to the camera system (3) where Camera II is located. Camera II moves synchronously and takes pictures at intervals. After the laser plane emitted by Laser I moves out of the transparent soil specimen again, adjust Laser I and Camera II to the initial positions. 5) The computer (4) controls Laser I to turn off and Laser II to turn on, and Camera I takes pictures of the speckle section formed in the soil body at the initial position of Laser II. 6) The computer (4) controls Laser II to move horizontally in the direction close to the camera system (3) where Camera I is located. Camera I moves synchronously and takes pictures at intervals. After the laser plane emitted by Laser II moves out of the transparent soil specimen, adjust Laser II and Camera I to the initial positions. The computer (4) controls Laser II to move horizontally in the direction close to the camera system (3) where Camera III is located. Camera III moves synchronously and takes pictures at intervals. After the laser plane emitted by Laser II moves out of the transparent soil specimen again, adjust Laser II and Camera III to the initial positions, and turn off Laser II. 7) Change the load of the servo actuator (101) according to the requirements, and repeat steps 3) - 6) to conduct the speckle section shooting of the soil body in the next stage until the loading is completed. 8) Perform image post-processing using PIV / DIC image processing software. 9) Use MATLAB software to perform interpolation and three-dimensional reconstruction processing on the slice displacement data obtained in step 8) to obtain the three-dimensional displacement of the entire soil body.

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