CN113405903B - Sand soil structure microscopic test method - Google Patents

Abstract

The invention relates to a sandy soil structure mesoscopic test method, which belongs to the technical field of geotechnical engineering, and its IPC classification number is E02D33/00. The test device that test method of the present invention adopts comprises reaction force mechanism, static force loading mechanism, model stacking mechanism, data acquisition system and photographing system; Reaction force mechanism comprises reaction force crossbeam and crossbeam height adjustment controller, and static force loading mechanism comprises A reducer, a lifter and a loading plate, the model stacking mechanism includes sand and soil particle simulation materials and a model frame, and the data acquisition system includes a pressure sensor and a data acquisition instrument. The test method of the invention can visually observe the particle changes inside the structure, test the displacement of the particles inside the sandy soil structure at each moment, and further clarify the internal particle movement law and the damage mechanism of the sandy soil structure, and has very low requirements for operators.

Description

A Mesoscopic Test Method for Sand and Soil Structure

technical field

The invention relates to an indoor model test method for geotechnical engineering, in particular to a sandy soil structure mesoscopic test method, which belongs to the technical field of geotechnical engineering, and its IPC classification number is E02D33/00.

Background technique

In geotechnical engineering, when studying the structural stability of foundations, slopes, retaining walls and embankments constructed of sand (sand) soil and other granular materials, it is usually necessary to carry out indoor model tests, among which the 3D model test is to study such rock and soil structures However, the three-dimensional model test studies the macroscopic manifestations of rock and soil structures, and it is impossible to know the movement rules of the particles inside the structure from the mesoscopic level, and in most cases, the operation is cumbersome and requires a certain amount of labor.

The existing invention patent CN201010182628 "Visualization device for contact surface shear test of interaction between soil and structure" can only realize the visual observation of the shear zone between soil and structure, and cannot analyze geotechnical engineering structures such as foundations, slopes, retaining walls and embankments. Wait for an all-round observation.

The existing invention patent CN201010142417 "rock and soil mechanics model test system and refined test method based on macro and mesoscopic mechanics" needs to integrate rock and soil mechanics model test, special mesoscopic image analysis technology, complex continuous-discrete coupling numerical simulation, etc. at the same time Only by means can the refined analysis of the test model be realized, the content is numerous, the operation is complicated, and the requirements for the test personnel are high. Since only a few high-level personnel can master the continuous-discrete coupled numerical simulation, this method has high requirements for test operators and analysts.

Contents of the invention

Therefore, the object of the present invention is to provide a kind of simple and quick sandy soil structure mesoscopic test method, technical solution of the present invention is as follows:

A sandy soil structure mesoscopic test method, the test device used includes a reaction force mechanism, a static loading mechanism, a model stacking mechanism, a data acquisition system and a shooting system; the reaction force mechanism includes a reaction force beam, slideways on both sides, Both sides of the suspension rope and crossbeam height adjustment controller, the static loading mechanism includes a motor, a reducer, a lift and a loading plate, the model stacking mechanism includes sand and soil particle simulation materials, a model frame and a placement box, the data acquisition The system includes a pressure sensor and a data acquisition instrument, and the shooting system includes a square illuminating board and a camera that can continuously take pictures.

The reaction force beam includes a beam and a connecting plate. Small screw holes are provided at both ends of the beam and one end of the connecting plate, and a large screw hole is provided at the other end of the connecting plate. The beam is connected to the connecting plate through the small screw hole, and the connecting plate passes through Large screw holes are fixed on the model frame, and multiple holes are set in the beam.

The slides on both sides include a slideway plate and a slideway block, the slideway plate is fixed on the model frame, the slideway block and the two ends of the beam are connected by strong glue, the slideway block can move up and down in the slideway plate, thereby driving The beam is adjusted up and down.

The height adjustment controller of the crossbeam is fixed on the outer wall of the model frame, the suspension ropes on both sides are wound on the height adjustment controller of the crossbeam through the pulleys on the upper part of the model frame, and the two ends of the crossbeam are suspended on the suspension ropes on both sides. Change the height of the crosshead by turning the handle of the crosshead height adjustment controller.

The motor, the reducer and the elevator are connected through the rotating shaft, and the reducer and the elevator are fixed on the beam through the screw I. The reducer is used to change the rotation speed of the rotating shaft, and then control the lifting speed of the elevator.

The lifting rod in the elevator passes through the beam through the hole provided in the beam, the bottom of the lifting rod has a flange, the flange is connected to the pressure sensor through screw II, the loading plate is connected to the pressure sensor through superglue, the lifting rod, the pressure sensor co-located with the longitudinal axis of the loading plate.

The sand particle simulation material is a cylindrical aluminum rod with a length of 6-10 cm and a diameter of 0.15 cm-0.6 cm.

The model frame is used for stacking sand and soil particle simulation materials. Fixing frames are provided on both sides of the bottom of the model frame to reinforce the model frame to ensure the overall stability of the model. The model frame is provided with multiple rows of screw holes for fixing The connecting plate at both ends of the reaction beam.

The test operation steps are as follows:

1) Connect the motor, reducer and elevator, and adjust the lifting speed of the lifting rod through the reducer to 1mm/min;

2) Use the beam height adjustment controller to adjust the beam to a height of 80cm from the bottom of the model frame, and fix the beam on the model frame through the connecting plate;

3) Select the particle gradation of each sand particle simulation material: select the fractal gradation that satisfies the mass fractal dimension D of 1.5 as the particle gradation. The selection method of fractal gradation is:

M(d<d _i )/M _T ＝(d _i /d _max ) ^3-D (1)

Where M _T refers to the total mass of all diameter particles, d _max refers to the diameter of the largest particle, d _i refers to the diameter of one of the particles, M(d<d _i ) refers to the mass of particles smaller than the diameter d _i and .

4) The total particle mass M _T is calculated using the following formula:

M _T =ρBHL×(1-n)(2)

Where ρ refers to the density of all particles, in general, ρ=2700kg/m ³ , B is the width of the foundation model, H is the height of the foundation model, L is the length of particles, n is the porosity of the foundation model, in general Take 0.2 down;

5) According to formula (2), the total particle mass M _T in the foundation model is calculated to be 155.5kg;

6) Select sandy soil particle simulation materials with diameters of 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm, 5.5mm, and 6.0mm, and calculate each The masses of the diameter particles are: 26.5kg, 10.5kg, 11.7kg, 12.7kg, 13.6kg, 14.5kg, 15.3kg, 16.1kg, 16.8kg, 17.6kg;

7) Fully mix the selected sand and soil particle simulation materials, and place them in the storage box for later use;

8) According to the size of the test simulation, the sand particle simulation material placed in the storage box is placed on the model frame. On the rear side of the simulated material accumulation body, when placing the simulated sand particle material, push the simulated sand particle material from the front side, so that the rear side of the simulated sand particle material contacts the flat plate, thereby ensuring the flatness of the front and rear surfaces of the simulated sand particle material accumulation body;

9) When placing sand and soil particle simulation materials, place an earth pressure sensor at the position where particle pressure needs to be monitored. When measuring vertical particle pressure, place the earth pressure sensor horizontally. When measuring horizontal particle pressure, place the earth pressure sensor vertically;

10) After the sand particle simulation material is stacked, install the pressure sensor and the loading plate on the lifting rod, open the static loading mechanism, and close the static loading mechanism when the loading plate is about to touch the sand particle simulation material;

11) Place the displacement sensor on the corresponding position of the sand particle simulation material accumulation body, and connect the insertion line in the displacement sensor, pressure sensor and earth pressure sensor with the data acquisition instrument, and use the data acquisition instrument to automatically record the value of the sensor;

12) Place the square lighting board and the camera in front of the model frame, so that the camera can take a full view of the sand particle simulation material accumulation;

13) Place the entire test model in a cuboid light-tight curtain shed; open the square lighting board and camera, take interval shots, and record the time when the camera starts shooting;

14) Start the static loading mechanism to load the sand particle simulation material accumulation, and record the initial loading time at the same time;

15) Continuously apply a vertical load to the sand particle simulation material accumulation body through the static loading mechanism. During the loading process, the camera continues to take pictures at intervals, and at the same time, the data acquisition instrument automatically records the sensor value until the end of the test;

16) Close the static loading mechanism, data acquisition instrument and camera;

17) Process the sensor data measured by the data acquisition instrument to obtain the relationship curve between the vertical displacement and vertical stress of the sand particle simulation material accumulation body, and the particle pressure distribution in the sand soil particle simulation material accumulation body;

18) Import the photos taken at intervals into PIV software for processing, and obtain the displacement and velocity of each particle, as well as the velocity field and displacement field of the entire sand particle simulation material accumulation body, and analyze the displacement field at the same time to obtain the sand particle simulation material accumulation body. destroy form.

Further, the data acquisition system also includes a displacement sensor and an earth pressure sensor.

The mesoscopic test method of the sand structure provided by the patent of the present invention can intuitively observe the particle changes inside the structure without combining numerical simulation means, and can test the displacement of the particles inside the sand structure at each moment, so as to clarify the internal particle movement law and the sand structure At the same time, the macroscopic mechanical performance of the model can be obtained, which provides a reference for the calculation and analysis of structures such as sandy soil and other granular foundations, slopes, retaining walls, and embankments; combined with the existing image processing technology PIV program, it can also analyze each structure inside the structure. The displacement and velocity of particles, as well as the velocity field, displacement field and damage form of the structure as a whole, are simple and fast to operate, and have very low requirements for operators.

Description of drawings

Fig. 1 is the test device schematic diagram that the present invention adopts;

Fig. 2 is the schematic diagram of the reaction beam of the present invention;

Fig. 3 is the schematic diagram of slideway on both sides of the present invention;

Fig. 4 is a schematic diagram of the lifting rod of the present invention;

Fig. 5 is a schematic diagram of the beam height adjustment controller of the present invention;

Fig. 6 is the schematic diagram of sand particle simulation material of the present invention;

Fig. 7 is a schematic diagram of the data acquisition system of the present invention;

Fig. 8 is a schematic diagram of a model frame of the present invention;

Fig. 9 is a schematic diagram of the placement box of the present invention;

Fig. 10 is a schematic diagram of the curtain booth of the present invention.

In the figure, 1. Reaction mechanism; 2. Static loading mechanism; 3. Model stacking mechanism; 4. Data acquisition system; 5. Shooting system; 6. Reaction beam; Side hanging rope; 9. Beam height adjustment controller; 10. Motor; 11. Reducer; 12. Elevator; 13. Loading plate; 14. Sand particle simulation material; 15. Model frame; 16. Placement box; 17. Pressure Sensor; 18. Data acquisition instrument; 19. Curtain shed; 20. Square lighting board; 21. Camera; 22. Beam; 23. Connecting plate; 24. Small screw hole; 25. Large screw hole; 26. Hole; 27. Slideway plate; 28, slideway block; 29, pulley; 30, handle; 31, rotating shaft; 32, screw Ⅰ; 33, lifting rod; 34, flange; 35, screw Ⅱ; 36, fixed frame; 37, screw hole; 38, flat plate; 39, displacement sensor; 40, earth pressure sensor.

Detailed ways

The present invention is described in detail below in conjunction with accompanying drawing.

A method for mesoscopic testing of sand and soil structures, the test device used includes a reaction mechanism 1, a static loading mechanism 2, a model stacking mechanism 3, a data acquisition system 4, and a shooting system 5; the reaction mechanism 1 includes a reaction beam 6. Slideways 7 on both sides, slings 8 on both sides and beam height adjustment controller 9, the static loading mechanism 2 includes a motor 10, a reducer 11, a lift 12 and a loading plate 13, and the model stacking mechanism 3 Including sand and soil particle simulation material 14, model frame 15 and placement box 16, the data acquisition system 4 includes a pressure sensor 17 and a data acquisition instrument 18, and the shooting system 5 includes a square lighting board 20 and a camera 21 that can continuously take pictures.

Reaction force crossbeam 6 comprises crossbeam 22 and connecting plate 23, and the two ends of crossbeam 22 and one end of connecting plate 23 are provided with small screw hole 24, and the other end of connecting plate 23 is provided with big screw hole 25, and crossbeam 22 passes described small screw The hole 24 is connected with the connecting plate 23, and the connecting plate 23 is fixed on the model frame 15 through a large screw hole 25, and a plurality of holes 26 are arranged in the beam 22.

Described slideway 7 comprises slideway block 27 and slideway block 28, and slideway block 28 is arranged in the middle of slideway plate 27, and slideway plate 27 is fixed on the model frame 15, and slideway block 28 and crossbeam 22 two ends adopt strong Connected by glue, the slideway block 28 can move up and down on the slideway plate 27, thereby driving the crossbeam 22 to adjust the up and down position.

The crossbeam height adjustment controller 9 is fixed on the outer side wall of the model frame 15, and the suspension ropes 8 on both sides are wound on the crossbeam height adjustment controller 9 by the pulley 29 on the top of the model frame 15, and the crossbeam 22 ends are suspended Hanging on both sides of the suspension rope 8, the height of the crossbeam 22 can be changed by turning the handle 30 of the crossbeam height adjustment controller 9.

Motor 10, reducer 11 and elevator 12 are connected by rotating shaft 31, and reducer 11 and elevator 12 are fixed on crossbeam 22 by screw I32, and reducer 11 is used for changing the rotational speed of rotating shaft 31, and then can control elevator 12 ascending and descending speeds.

The lifting rod 33 in the elevator 12 passes through the beam 22 through the hole 26 provided in the beam 22, the bottom of the lifting rod 33 has a flange 34, the flange 34 is connected to the pressure sensor 17 through the screw II 35, and the loading plate 13 is connected by superglue Connected with the pressure sensor 17, the lifting rod 33, the pressure sensor 17 and the longitudinal axis of the loading plate 13 are at the same position.

The sand particle simulation material 14 is a cylindrical aluminum rod with a length of 6-10 cm and a diameter (ie particle size) of 0.15 cm-0.6 cm. The specific gravity of the aluminum rod material is close to that of the soil, so this application chooses the aluminum rod as the sand particle simulation material for research. The placement box 16 is open and placed on one side of the model frame 15 for placing sand and soil particle simulation materials 14 before the test starts and after the test ends.

Described model frame 15 is used for heaping sand and soil particle simulation material 14, and the bottom both sides of model frame 15 is provided with fixed frame 36, is used for reinforcing model frame 15, guarantees the integral stability of model, is provided with multiple rows on model frame 15. The screw holes 37 are used to fix the connecting plates 23 at both ends of the reaction beam 6 .

During the test, the square lighting board 20 and the camera 21 that can be photographed continuously are placed in front of the model frame 15 for observing the movement law of the sand particle simulation material 14 during the test, and then the whole model device is placed in a cuboid light-proof Curtain shed 19.

Taking the foundation model as an example, the implementation method of the sandy soil structure mesoscopic test method proposed by the present invention will be described in detail below. The foundation model is 120cm wide and 60cm high, as shown in Figure 1. The specific test steps are as follows:

1) Connect the motor 10, the reducer 11 and the elevator 12, and adjust the lifting speed of the lifting rod 33 through the reducer 11 to be 1mm/min;

2) adjust the crossbeam 22 to a height position of 80 cm from the bottom of the model frame 15 by the crossbeam height adjustment controller 9, and fix the crossbeam 22 on the model frame 15 by the connecting plate 23;

3) Select the particle gradation of each sand particle simulation material (that is, select the mass of particles of each particle size). When there is no special requirement for particle gradation, select the fractal gradation that satisfies the quality fractal dimension D of 1.5 as the particle Grading. The selection method of fractal gradation is:

M(d<d _i )/M _T ＝(d _i /d _max ) ^3-D (1)

Where M _T refers to the total mass of all diameter particles, d _max refers to the diameter of the largest particle, d _i refers to the diameter of one of the particles, M(d<d _i ) refers to the mass of particles smaller than the diameter d _i and .

4) The total particle mass M _T is calculated using the following formula:

M _T =ρBHL×(1-n)(2)

Where ρ refers to the density of all particles, in general, ρ=2700kg/m ³ , B is the width of the foundation model, H is the height of the foundation model, L is the length of particles, n is the porosity of the foundation model, in general Take 0.2 down;

5) According to formula (2), the total particle mass M _T in the foundation model is calculated to be 155.5kg;

5) According to formula (2), the total particle mass M _T in the foundation model is calculated to be 155.5kg;

6) Select sand and soil particle simulation materials 14 with diameters of 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm, 5.5mm, and 6.0mm, and calculate each The masses of particles with different diameters are: 26.5kg, 10.5kg, 11.7kg, 12.7kg, 13.6kg, 14.5kg, 15.3kg, 16.1kg, 16.8kg, 17.6kg;

7) fully mix the particles in the selected sand particle simulation material 14, and place them in the storage box 16 for standby;

8) According to the size of the foundation model, the sand particle simulation material 14 placed in the placement box 16 is placed on the model frame 15. In order to ensure that the front and rear surfaces of the sand particle simulation material 14 are piled up, a flat plate with the same width as the model, 15 38 is placed on the rear side of the sand particle simulation material 14 accumulation body. When the sand particle simulation material 14 is placed, the sand particle simulation material 14 is pushed from the front side so that the rear side of the sand particle simulation material 14 contacts the flat plate 38, thereby ensuring the sand particle simulation material 14. The flatness of the front and rear side surfaces of the stack of materials 14;

9) When placing the sand particle simulation material 14, place the earth pressure sensor 40 at the position where the particle pressure needs to be monitored. When the earth pressure sensor 40 is placed horizontally, the vertical particle pressure is measured, and when placed vertically, the measured is Horizontal particle pressure;

10) After the foundation model is stacked, install the pressure sensor 17 together with the loading plate 13 on the lifting rod, open the static loading mechanism 2, and turn off the switch when the loading plate 13 is about to touch the sand particle simulation material 14;

11) Displacement sensor 39 is placed on the corresponding position of foundation model, and the insertion line in displacement sensor 39, pressure sensor 17 and earth pressure sensor 40 is connected with data acquisition instrument 18, utilizes data acquisition instrument 18 to automatically record the numerical value of sensor;

12) Place the square lighting board 20 and the camera 21 before the model frame 15, so that the camera 21 can take a picture of the model;

13) The whole test model is placed in a cuboid light-tight curtain shed 19; open the square lighting plate 20 and the camera 21, take interval shots, and record the time when the camera 21 starts to shoot;

14) Start the static loading mechanism 2 to load the foundation model, and record the initial loading time at the same time;

15) Apply a vertical load to the sand particle simulation material through the static loading mechanism 2. During the loading process, the camera 21 is used to continue taking interval shots, and the data acquisition instrument 18 continues to automatically record the sensor values until the end of the test;

16) After the test is over, close the static loading mechanism 2, the data acquisition instrument 18 and the camera 21;

17) Process the sensor data measured by the data acquisition instrument 18 to obtain the relationship curve between the vertical displacement and the vertical stress of the sandy soil particle simulation material foundation, and the particle pressure distribution of the sandy soil particle simulation material in the foundation;

18) The photos taken at intervals are imported into PIV software for processing to obtain the displacement and velocity of each particle as well as the velocity field and displacement field of the entire structure, and at the same time analyze the displacement field to obtain the failure form of the foundation.

Claims (2)

1. a sandy soil structure mesoscopic test method, is characterized in that, the test device that adopts comprises reaction force mechanism (1), static loading mechanism (2), model stacking mechanism (3), data acquisition system (4) and Shooting system (5); the reaction force mechanism (1) includes a reaction force beam (6), slideways on both sides (7), hanging ropes on both sides (8) and a beam height adjustment controller (9), the static Force loading mechanism (2) comprises electric motor (10), speed reducer (11), elevator (12) and loading plate (13), and described model stacking mechanism (3) comprises sand particle simulation material (14), model frame ( 15) and place box (16), described data acquisition system (4) comprises pressure sensor (17) and data acquisition instrument (18), and described photographing system (5) comprises square illuminator (20) and can take pictures continuously camera(21); Reaction beam (6) comprises crossbeam (22) and connecting plate (23), and the two ends of crossbeam (22) and an end of connecting plate (23) are provided with small screw hole (24), the other end of connecting plate (23) A large screw hole (25) is provided, and the beam (22) is connected with the connecting plate (23) through the small screw hole (24), and the connecting plate (23) is fixed on the model frame (15) through the large screw hole (25) , a plurality of holes (26) are set in the beam (22); Described both sides slideway (7) comprises slideway plate (27) and slideway block (28), slideway plate (27) is fixed on the model frame (15), slideway piece (28) and crossbeam (22) The two ends are connected by strong glue, and the slideway block (28) can move up and down in the slideway plate (27), thereby driving the crossbeam (22) to adjust the up and down position; The crossbeam height adjustment controller (9) is fixed on the outer wall of the model frame (15), and the hanging ropes (8) on both sides are wound around the crossbeam height adjustment by the pulley (29) on the top of the model frame (15). On the controller (9), the two ends of the crossbeam (22) are suspended from the hanging ropes (8) on both sides, and the height of the crossbeam (22) is changed by turning the handle (30) of the height adjustment controller (9); The motor (10), the reducer (11) and the elevator (12) are connected through a rotating shaft (31), the reducer (11) and the elevator (12) are fixed on the beam (22) by screws I (32), and the reducer (11) Used to change the rotating speed of the rotating shaft (31), and then control the lifting speed of the elevator (12); The lifting rod (33) in the elevator (12) passes through the cross beam (22) through the hole (26) provided in the cross beam (22), and the bottom of the lifting rod (33) has a flange (34), and the flange (34 ) is connected to the pressure sensor (17) through screw II (35), the loading plate (13) is connected to the pressure sensor (17) through superglue, and the longitudinal direction of the lifting rod (33), the pressure sensor (17) and the loading plate (13) the axes are in the same position; The sandy soil particle simulation material (14) is a cylindrical aluminum rod with a length of 6-10cm and a diameter of 0.15cm-0.6cm; Described model frame (15) is used for heaping sand and soil particle simulation material (14), and the bottom both sides of model frame (15) is provided with fixed frame (36), is used for reinforcing model frame (15), guarantees the overall stability of model The model frame (15) is provided with multiple rows of screw holes (37), which are used to fix the connecting plates (23) at both ends of the reaction beam (6); The test operation steps are as follows: 1) Connect the motor (10), the reducer (11) and the elevator (12), and adjust the lifting speed of the lifting rod (33) through the reducer (11) to be 1mm/min; 2) Use the beam height adjustment controller (9) to adjust the beam (22) to a height of 80 cm from the bottom of the model frame (15), and fix the beam (22) to the model frame (15) through the connecting plate (23) ; 3) Select the particle gradation of each sand particle simulation material: select the fractal gradation that satisfies the mass fractal dimension D of 1.5 as the particle gradation; the selection method of the fractal gradation is: M(d<d _i )/M _T ＝(d _i /d _max ) ^3-D (1) Where M _T refers to the total mass of all diameter particles, d _max refers to the diameter of the largest particle, d _i refers to the diameter of one of the particles, M(d<d _i ) refers to the mass of particles smaller than the diameter d _i and ; 4) The total particle mass M _T is calculated using the following formula: M _T =ρBHL×(1-n) (2) Where ρ refers to the density of all particles, in general, ρ=2700kg/m ³ , B is the width of the foundation model, H is the height of the foundation model, L is the length of particles, n is the porosity of the foundation model, in general Take 0.2 down; 5) According to formula (2), the total particle mass M _T in the foundation model is calculated to be 155.5kg; 6) Select sand and soil particle simulation materials (14) with diameters of 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm, 5.5mm, and 6.0mm, and calculate according to formula (1) The masses of particles of each diameter obtained are: 26.5kg, 10.5kg, 11.7kg, 12.7kg, 13.6kg, 14.5kg, 15.3kg, 16.1kg, 16.8kg, 17.6kg; 7) Fully mix the selected sand and soil particle simulation material (14), and put it in the storage box (16) for standby; 8) According to the size of the test simulation, the sand particle simulation material (14) placed in the placement box (16) is placed on the model frame (15), in order to ensure that the front and rear surfaces of the sand particle simulation material (14) are flat, Place the flat plate (38) equal to the width of the model frame (15) on the rear side of the sand particle simulation material (14), when the sand particle simulation material (14) is placed, push the sand particle simulation material (14) from the front side ), so that the rear side of the sand particle simulation material (14) contacts the flat plate (38), thereby ensuring the flatness of the front and rear side surfaces of the sand particle simulation material (14) accumulation body; 9) When placing the sand particle simulation material (14), place the earth pressure sensor (40) at the position where the particle pressure needs to be monitored. When measuring the vertical particle pressure, place the earth pressure sensor (40) horizontally to measure the horizontal particle pressure , the earth pressure sensor (40) is placed vertically; 10) After the sand particle simulation material (14) is piled up, install the pressure sensor (17) together with the loading plate (13) on the lifting rod (33), and open the static loading mechanism (2). When the loading plate (13) is about to When the sand particle simulation material (14) is contacted, the static loading mechanism (2) is closed; 11) Place the displacement sensor (39) on the corresponding position of the sand particle simulation material (14) accumulation body, and connect the plug-in wires in the displacement sensor (39), the pressure sensor (17) and the earth pressure sensor (40) to the data acquisition Instrument (18) is connected, utilizes data acquisition instrument (18) to automatically record the numerical value of sensor; 12) Place the square lighting board (20) and the camera (21) in front of the model frame (15), so that the camera (21) can take a picture of the accumulation body of the sand particle simulation material (14); 13) The whole test model is placed in a cuboid light-tight curtain shed (19); open the square lighting plate (20) and camera (21), perform interval shooting, and record the time when the camera (21) starts shooting; 14) Start the static loading mechanism (2) to load the accumulation of the sand particle simulation material (14), and record the initial loading time at the same time; 15) The static loading mechanism (2) continuously applies a vertical load to the sand particle simulation material (14) accumulation, the camera (21) continues to take interval shots during the loading process, and the data acquisition instrument (18) automatically records the sensor value , until the end of the test; 16) Close static loading mechanism (2), data acquisition instrument (18) and camera (21); 17) Process the sensor data measured by the data acquisition instrument (18) to obtain the relationship curve between the vertical displacement and the vertical stress of the sand particle simulation material (14) accumulation body, and the sand particle simulation material (14) accumulation body. Particle pressure distribution; 18) Import the photos taken at intervals into PIV software for processing to obtain the displacement and velocity of each particle and the velocity field and displacement field of the entire sand particle simulation material (14) accumulation body, and analyze the displacement field at the same time to obtain the sand particle simulation material (14) Destruction form of accumulation. 2. A sandy soil structure mesoscopic test method according to claim 1, characterized in that the data acquisition system (4) further comprises a displacement sensor (39) and an earth pressure sensor (40).

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