An indoor plate load test device and method considering the influence of foundation burial depth

Abstract

The present invention discloses an indoor flat plate load test apparatus and method that considers the influence of foundation burial depth. By integrating a flexible airbag, a reaction frame, and a foundation pressure plate, the present invention cleverly simulates the stress of the surrounding soil under the influence of foundation burial depth through gas stress. The apparatus is ingeniously designed and simple to operate. The present invention can simulate the stress of the surrounding soil caused by the foundation burial depth, thereby enabling indoor flat plate load tests under the influence of foundation burial depth to be conducted. This allows for the study of the bearing characteristics and failure modes of foundation soil under different foundation burial depths, making the results of indoor flat plate load tests more consistent with engineering practice and the results and conclusions more valuable for reference.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering tests, and in particular relates to an indoor flat plate load test device and method taking into account the influence of foundation burial depth. Background Art

[0002] The indoor plate load test is an important soil mechanics test, which can be used to evaluate the bearing capacity and deformation characteristics of foundation soil. In the routine indoor plate load test process, the load plate used to simulate the shallow foundation is often placed directly on the surface of the foundation soil, ignoring the influence of the foundation burial depth (or the stress of the covering soil around the foundation) on the bearing capacity and deformation characteristics of the foundation soil. However, in actual engineering, the shallow foundation is not built directly on the foundation surface, but has a certain burial depth, that is, the foundation soil at the bottom of the shallow foundation is subject to a certain stress of the covering soil around the foundation. In order to enable the indoor plate load test to better simulate the engineering behavior of the foundation soil in actual engineering, it is necessary to develop an indoor plate load test device and method that takes into account the influence of the foundation burial depth condition. Summary of the Invention

[0003] Based on the above-mentioned existing technology, the present invention provides an indoor flat plate load test device and method that takes into account the influence of foundation burial depth. The present invention has a simple structure and ingenious design. It can simulate the stress of the covering soil around the foundation caused by the foundation burial depth, so that indoor flat plate load tests considering the influence of foundation burial depth can be carried out, and the bearing characteristics and failure modes of foundation soil under different foundation burial depth conditions can be studied, so that the results of indoor flat plate load tests are more in line with engineering practice, and the results and conclusions are more valuable for reference.

[0004] The technical solution adopted to achieve the above-mentioned purpose of the present invention is:

[0005] An indoor flat plate load test device that takes into account the influence of foundation burial depth includes a transparent model box, a burial depth simulation mechanism, a load loading mechanism, and a reaction frame. The reaction frame is fixed to the ground and has a placement position for the model box inside the reaction frame.

[0006] The burial depth simulation mechanism includes a flexible airbag, an air pump, an air pipe, and a stress controller. One end of the air pipe is connected to the flexible airbag, and the other end is installed on the air pump. The air pump is equipped with a gas stress sensor for sensing the gas stress in the flexible airbag. The stress controller is electrically connected to the air pump and the gas stress sensor respectively.

[0007] When the inflated flexible airbag is placed in the model box, the side wall of the inflated flexible airbag contacts or fits with the inner wall of the model box;

[0008] The load loading mechanism includes a base pressure plate, a vertical load device and a load controller. The base pressure plate is strip-shaped, and a groove for placing the base pressure plate is provided on the flexible airbag. The groove is strip-shaped and extends to the top and bottom of the flexible airbag respectively. One end of the groove extends to the side wall of the flexible airbag. When the base pressure plate is placed in the groove on the inflated flexible airbag, the side wall of the base pressure plate is completely in contact with or fits the side wall of the groove. The vertical load device is installed on the reaction frame. The load applying part of the vertical load device is located directly above the model box placement position. A displacement sensor is installed on the load applying part of the vertical load device. The vertical load device applies a vertical load to the base pressure plate, and the load controller controls the magnitude of the applied vertical load.

[0009] The vertical load device is a hydraulic jack, which includes a housing, a piston rod and an oil pump. The housing is fixed on the reaction frame, the piston rod faces downward, and the load controller is electrically connected to the oil pump.

[0010] The bottom of the load applying part of the vertical load device is provided with a loading plate that cooperates with the foundation pressure plate. The bottom of the load applying part of the vertical load device is connected to the middle part of the loading plate. The loading plate is strip-shaped, and the size of the loading plate is adapted to the size of the foundation pressure plate. A displacement sensor is embedded in the loading plate or the load applying part of the vertical load device.

[0011] The base pressure plate and the loading plate are both square, the length of the loading plate is the same as that of the base pressure plate, and the width of the loading plate is less than or equal to that of the base pressure plate.

[0012] The flexible air bag is provided with an air release valve.

[0013] It also includes a pair of slide rails, which are symmetrically installed on the ground. The bottom of the model box is provided with at least one pair of pulleys that cooperate with the slide rails. The model box can be moved along the pair of slide rails to the model box placement position.

[0014] It also includes a deformation measurement mechanism, which includes a camera and an image analysis and processing module, and the camera and the image analysis and processing module are electrically connected.

[0015] An indoor plate load test method considering the influence of foundation burial depth includes the following steps:

[0016] S1. Lay the soil sample in the model box to simulate the foundation;

[0017] S2. Turn on the air pump to inflate the flexible airbag. When the volume of the gas inflated into the flexible airbag reaches 75-85% of the volume of the flexible airbag, turn off the air pump to stop inflating.

[0018] S3. Place the base pressure plate in the groove of the flexible airbag so that the side wall of the base pressure plate is in full contact or in contact with the side wall of the groove;

[0019] S4. Place the flexible airbag in the model box so that the bottom of the flexible airbag is located on the foundation. At the same time, make the side wall of the inflated flexible airbag contact or fit with the inner wall of the model box, and make one end of the base pressure plate contact with the inner wall of the model box. Press the base pressure plate so that the bottom surface of the base pressure plate contacts the foundation.

[0020] S5. Place the model box in the placement position inside the reaction frame, with the top of the flexible airbag close to the reaction frame. Turn on the vertical load device, move the load applying part of the vertical load device downward, observe the load applying part of the vertical load device, and turn off the vertical load device when the load applying part of the vertical load device contacts the top surface of the foundation bearing plate.

[0021] S6. Calculate the additional stress σ1 given to the foundation by the surrounding soil of the simulated foundation according to the buried depth h1 of the simulated foundation:

[0022] σ1=ρ1×g×h1

[0023] Among them, ρ1 is the density of the soil sample, h1 is the foundation depth to be simulated;

[0024] A preset stress σ1 is set through the stress controller, the stress controller and the air pump are turned on, and the flexible airbag continues to be inflated. When the gas stress sensor senses that the gas stress in the flexible airbag has reached the preset stress σ1, the gas stress sensor feeds back a signal to the stress controller, and the stress controller controls the air pump to shut down and stop inflating the flexible airbag. At this time, the flexible airbag swells and gives a thrust to the reaction frame, the reaction frame gives a reverse thrust to the flexible airbag, and the flexible airbag gives a thrust to the foundation. The thrust given by the flexible airbag to the foundation is the additional force given to the foundation by the covering soil around the foundation to be simulated, and the additional stress given to the foundation by the covering soil around the foundation to be simulated is σ1;

[0025] S7. Turn on the vertical load device, and the load applying portion of the vertical load device continues to move downward. The load applying portion of the vertical load device pushes the foundation pressure plate to continue to move downward. The downward movement of the foundation pressure plate is observed. When the foundation pressure plate contacts the foundation, turn off the vertical load device and reset the displacement sensor at the same time.

[0026] S8. Set the preset load of the load controller to F1, turn on the load controller and the vertical load device, and the load applying part of the vertical load device applies the vertical load F1 to the foundation bearing plate. The settlement distance L1 of the foundation bearing plate can be measured by the displacement sensor;

[0027] S9, gradually increasing the preset load to F2...Fn, repeating step S8 each time the preset load is increased, and measuring the corresponding settlement distances of the foundation bearing plate to be L2...Ln respectively, until the settlement distance of the foundation bearing plate reaches the relevant requirements in the specification, and then ending the test;

[0028] S10. When it is necessary to simulate the influence of different foundation burial depths on the indoor flat plate load test, repeat steps S1-S9;

[0029] S11. When it is necessary to change a different soil sample to perform an indoor flat plate load test under the influence of foundation burial depth, repeat steps S1-S10.

[0030] Furthermore, in step S8, the camera may capture the deformation of the soil sample.

[0031] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0032] 1. The present invention cleverly simulates the stress of the covering soil around the foundation under the influence of the foundation burial depth by means of gas stress through the coordination between the flexible airbag, the reaction frame and the foundation pressure plate. The design is ingenious and the operation is simple.

[0033] 2. The present invention modifies the piston rod of the commonly used vertical load-applying device jack and adds a strip-shaped loading plate at the end of the piston rod, thereby changing the point contact to surface contact during vertical load loading. This avoids the phenomenon that point contact during vertical load loading causes the foundation pressure plate to tilt (or uneven foundation settlement), which causes inaccurate measurements by the displacement sensor installed on the foundation pressure plate. The present application installs the displacement sensor on the loading plate, and the shape and size of the loading plate match the foundation pressure plate, preventing tilt, thereby making the settlement measurement of the foundation pressure plate more accurate and reliable.

[0034] 3. The present invention can simulate the foundation burial depth to give the foundation surrounding soil stress, and provides an indoor plate load test method that takes into account the influence of foundation burial depth, so that the foundation soil in the indoor plate load test (especially the influence of the foundation soil around the foundation) is more in line with its actual stress state, and the results and conclusions are more valuable for reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the indoor plate load test device considering the influence of foundation depth.

[0036] Among them, 1-model box, 2-reaction support platform, 3-support leg, 4-ear plate, 5-flexible airbag, 6-groove, 7-air pump, 8-air pipe, 9-stress controller, 10-air relief valve, 11-base pressure plate, 12-load controller, 13-oil pump, 14-loading plate, 15-camera, 16-camera bracket, 17-slide rail. DETAILED DESCRIPTION

[0037] The indoor flat plate load test device considering the influence of foundation burial depth of the present invention is described in detail below with reference to the accompanying drawings.

[0038] Example 1

[0039] The structural diagram of the indoor flat plate load test device considering the influence of foundation burial depth provided in this embodiment is as follows: Figure 1 As shown, it includes a transparent model box 1, a buried depth simulation mechanism, a load loading mechanism, a reaction frame, a slide rail 4 and a deformation measuring mechanism.

[0040] The model box 1 is square in shape, with sidewalls made of 5mm-thick transparent tempered glass. The net dimensions of its internal cavity are determined based on the shape and dimensions of the foundation bearing plate 11, taking into account the impact of the box boundary on the diffusion of foundation soil stress. The internal dimensions of the model box are 75cm × 45cm × 55cm (length × width × height). Two pairs of pulleys are installed at the bottom of the model box, distributed along the width of the model box 1. The symmetry plane of each pair of pulleys is the same as the symmetry plane of the model box 1, and the four pulleys are arranged in a square shape.

[0041] The reaction frame is made of Q35 high-quality carbon structural steel. The reaction frame includes a reaction support platform 2 and support legs 3. The reaction support platform 2 is square. There are four support legs 3, and the four support legs 3 are vertically arranged and distributed in a square. The upper ends of the four support legs 3 are respectively connected to the four corners of the reaction support platform 2, and the lower ends of the four support legs 3 are respectively connected to ear plates 4. Each support leg 3 and the corresponding ear plate 4 are connected to form an L-shaped structure, and the 90-degree angle of the L-shaped structure faces outward. The four ear plates 4 are respectively fixed to the ground by anchor bolts, thereby firmly fixing the reaction frame. The rectangular space surrounded by the reaction support platform 2, the four support legs 3 and the ground is used to place and fix the model box 1. The length of the rectangular space is slightly larger than the length of the outer contour of the model box 1, and the width of the rectangular space is slightly larger than the width of the outer contour of the model box 1. When the model box is located directly below the reaction support platform 2, there is a certain distance between the reaction support platform 2 and the top of the model box 1. The distance is the space left for the deflation valve 10. At the same time, the distance cannot be too large, otherwise the flexible airbag cannot touch the bottom surface of the reaction support platform 2 even when it is inflated. Generally, this distance is set to 5 cm. There is a pair of slide rails 17, and the pair of slide rails 17 are symmetrically installed on the ground. The same side of the two slide rails 17 is located directly below the reaction support platform 2, and the symmetry plane of the two slide rails 17 is the same as the symmetry plane of the reaction support platform 2. The cooperation between the slide rails 17 and the pulleys on the model box 1 facilitates the installation and disassembly of the model box 1.

[0042] The burial depth simulation mechanism includes a flexible airbag 5, an air pump 7, an air pipe 8, and a stress controller 9. The flexible airbag 5 is made of 1.2 mm thick rubber and polyester fiber mesh, and can apply uniform stress to the foundation soil when inflated. When the flexible airbag 5 is inflated, the flexible airbag 5 is square in shape. When the flexible airbag 5 is placed in the model box, the side wall of the flexible airbag 5 fits the inner wall of the model box 1. The flexible airbag 5 is provided with a groove 6 for placing the foundation pressure plate. The groove 6 is in the shape of a square strip and extends to the top and bottom of the flexible airbag 5 respectively. One end of the groove 6 extends to the side wall of the flexible airbag.

[0043] One end of the air tube 8 is connected to the flexible airbag 5, and the other end is mounted on the air pump 7. The air pump 7 is equipped with a gas stress sensor (XGZP6847A 500kPa gas stress sensor) for sensing the gas stress within the airbag. The flexible airbag 5 is also equipped with a deflation valve 10. A stress controller 9 is electrically connected to the air pump 7 and the gas stress sensor. The stress controller is key to ensuring stable loading of the flexible airbag 5. By adjusting the air pump 7, the stress applied to the flexible airbag 5 is kept constant at the designed value.

[0044] The load-applying mechanism includes a foundation bearing plate 11, a vertical load device, and a load controller 12. The foundation bearing plate 11 is used to simulate a shallow strip foundation. It is square and strip-shaped, constructed from steel plates measuring 50 cm × 5 cm × 2 cm (length × width × thickness). When placed in the groove 6 of the inflated flexible airbag 5, the sidewalls of the plate 11 completely conform to the sidewalls of the groove 5.

[0045] The vertical load device is a hydraulic jack (DZG150-200 hydraulic jack), which includes a shell, a piston rod and an oil pump 13. The shell is fixed on the reaction support platform 2, with the piston rod facing downward. A loading plate 14 that cooperates with the base pressure plate is provided on the lower end of the piston rod, and the loading plate 14 is in the shape of a square strip. The length of the loading plate 14 is the same as the length of the base pressure plate 11, and the width of the loading plate 14 is equal to the width of the base pressure plate 11. The lower end of the piston rod is connected to the middle part of the loading plate 14, and the piston rod and the loading plate 14 form a T-shaped structure. The reaction support platform 2 is provided with space for the piston rod and the loading plate 14 to rise and fall, and the piston rod and the loading plate 14 can move through the bottom of the reaction support platform 2. A displacement sensor is embedded in the loading plate 14 to measure the settlement of the base pressure plate 11.

[0046] The deformation measurement mechanism includes a camera 15, a camera bracket 16, and an image analysis and processing module. Camera 15 is mounted on the bracket 16 and electrically connected to the image analysis and processing module. The camera is used to record the deformation of the soil sample within the model box during the load test. The image analysis and processing module utilizes PhotoInfor, an image analysis software developed by Professor Li Yuanhai of the China University of Mining and Technology based on digital photodeformation measurement (DPDM) technology, and PostViewer, a post-processing software. These software accurately captures and measures foundation deformation without markers.

[0047] The shallow foundation load test method under the influence of burial depth of the present invention is described in detail below in conjunction with the above-mentioned device.

[0048] Example 2

[0049] S1. According to Figure 1 The structure shown is to install the slide rail 17, reaction frame, hydraulic jack, load controller 12 and deformation measurement mechanism;

[0050] S2. Using the rain method, calcareous sand is laid in three layers in the model box 1, with each layer thickness controlled at 15 cm to simulate the calcareous sand foundation;

[0051] S3, turn on the air pump 7 to inflate the flexible airbag 5. When the flexible airbag 5 is just inflated and relatively soft (about 80% inflated), turn off the air pump 7 to stop inflating;

[0052] S4. Place the base pressure plate 11 in the groove 6 of the flexible airbag 5 so that the sidewalls of the base pressure plate 11 are completely in contact with the sidewalls of the groove 6. Inflate the flexible airbag to about 80% to make the flexible airbag 5 bulge, making it easier to place the base pressure plate 11 in the groove 6.

[0053] S5. Place the flexible airbag 5 in the model box 1 so that the bottom of the flexible airbag 5 is on the foundation. At the same time, make the side wall of the inflated flexible airbag 5 fit the inner wall of the model box 1, and make one end of the base pressure plate 11 contact the inner wall of the model box 1. This makes it easy to observe the dynamics of the base pressure plate 11. Press the base pressure plate 11 so that the bottom surface of the base pressure plate 11 contacts the foundation.

[0054] S6. Place the model box 1 on the slide rail 17 and then push the model box 1 into the rectangular space directly below the reaction support platform 2. At this time, the top of the flexible airbag 5 is close to the bottom of the reaction support platform 2. Turn on the oil pump 13, and the loading plate 14 moves downward under the drive of the piston rod. Observe the downward movement of the loading plate 14. When the bottom surface of the loading plate 14 is completely in contact with the top surface of the base pressure plate 11, turn off the oil pump.

[0055] S7. If the density of foundation soil is 1.5g / cm3 , setting the buried depth of the foundation to be simulated to 3 meters, then according to the buried depth of the foundation to be simulated and the density of the foundation soil, the additional stress of the foundation given by the covering soil around the foundation to be simulated is calculated to be 45kPa. Set the preset stress to 45kPa through the stress controller 9, turn on the stress controller 9 and the air pump 7, and continue to inflate the flexible airbag 5. When the gas stress sensor senses that the gas stress in the flexible airbag 5 has reached the preset stress of 45kPa, the gas stress sensor feeds back a signal to the stress controller 9, and the stress controller controls the air pump 7 to shut down and stop inflating the flexible airbag 5. At this time, the flexible airbag 5 gives a thrust to the bottom of the reaction support platform 2, and the reaction support platform 2 gives a reverse thrust to the flexible airbag 5, and the flexible airbag gives a thrust to the foundation. The thrust given by the flexible airbag to the foundation is the additional force given to the foundation by the covering soil around the foundation to be simulated. The additional stress given to the foundation by the covering soil around the foundation to be simulated is 45kPa.

[0056] S8. Turn on the oil pump. Driven by the piston rod, the loading plate 14 continues to move downward. The loading plate 14 pushes the base pressure plate 44 to continue to move downward. Observe the downward movement of the base pressure plate 44. When the base pressure plate 44 contacts the foundation, turn off the oil pump 13 and reset the displacement sensor.

[0057] S9. Set the preset stress of the load controller 12 to 50 kPa, turn on the load controller 12 and the oil pump 13, and apply a vertical load of 50 kPa to the foundation bearing plate 11 with the loading plate 14. The settlement distance of the foundation bearing plate 11 can be measured by the displacement sensor. At the same time, the camera 15 can capture the deformation of the soil sample and analyze and process it through the image analysis and processing module.

[0058] S10, gradually increase the vertical load by 50 kPa, repeat step S8, measure the corresponding settlement of the foundation bearing plate, and terminate the test when the settlement distance of the foundation bearing plate reaches the relevant provisions in the specification;

[0059] S12 , after the load test is completed, the loading plate 14 is reset, the model box 1 is pushed out, the flexible airbag 5 is taken out and the air is deflated through the deflation valve 10 .

Claims

1. An indoor flat plate load test device considering the influence of foundation burial depth, characterized by: It includes a transparent model box, a burial depth simulation mechanism, a load loading mechanism and a reaction frame. The reaction frame is fixed on the ground and has a placement position for the model box inside the reaction frame. The burial depth simulation mechanism includes a flexible airbag, an air pump, an air pipe, and a stress controller. One end of the air pipe is connected to the flexible airbag, and the other end is installed on the air pump. The air pump is equipped with a gas stress sensor for sensing the gas stress in the flexible airbag. The stress controller is electrically connected to the air pump and the gas stress sensor respectively. When the inflated flexible airbag is placed in the model box, the side wall of the inflated flexible airbag contacts or fits with the inner wall of the model box; The load loading mechanism includes a base bearing plate, a vertical load device and a load controller. The vertical load device is a hydraulic jack. The hydraulic jack includes a housing, a piston rod and an oil pump. The housing is fixed on the reaction frame, the piston rod faces downward, and the load controller is electrically connected to the oil pump. The basic pressure-bearing plate is in a strip shape, and a groove for placing the basic pressure-bearing plate is provided on the flexible airbag. The groove is in a strip shape and extends to the top and bottom of the flexible airbag respectively. One end of the groove extends to the side wall of the flexible airbag. When the basic pressure-bearing plate is placed in the groove on the inflated flexible airbag, the side wall of the basic pressure-bearing plate is in full contact or fit with the side wall of the groove. The load applying part of the vertical load device is located directly above the model box placement position. A loading plate that cooperates with the foundation pressure plate is provided at the bottom of the load applying part of the vertical load device. The bottom of the load applying part of the vertical load device is connected to the middle part of the loading plate. The loading plate is strip-shaped, and the size of the loading plate is adapted to the size of the foundation pressure plate. A displacement sensor is embedded in the loading plate or the load applying part of the vertical load device. The vertical load device applies a vertical load to the foundation bearing plate, and the load controller controls the magnitude of the applied vertical load.

2. The indoor flat plate load test device considering the influence of foundation burial depth according to claim 1 is characterized in that: The base pressure plate and the loading plate are both square, the length of the loading plate is the same as that of the base pressure plate, and the width of the loading plate is less than or equal to that of the base pressure plate.

3. The indoor flat plate load test device considering the influence of foundation burial depth according to claim 1 is characterized in that: The flexible air bag is provided with an air release valve.

4. The indoor flat plate load test device considering the influence of foundation burial depth according to claim 1 is characterized in that: It also includes a pair of slide rails, which are symmetrically installed on the ground. The bottom of the model box is provided with at least one pair of pulleys that cooperate with the slide rails. The model box can be moved along the pair of slide rails to the model box placement position.

5. The indoor flat plate load test device considering the influence of foundation depth according to claim 1 is characterized in that: It also includes a deformation measurement mechanism, which includes a camera and an image analysis and processing module, and the camera and the image analysis and processing module are electrically connected.

6. A test method based on the indoor flat plate load test device considering the influence of foundation depth according to claim 1, characterized in that The steps include: S1. Lay the soil sample in the model box to simulate the foundation; S2. Turn on the air pump to inflate the flexible airbag. When the volume of the gas inflated into the flexible airbag reaches 75-85% of the volume of the flexible airbag, turn off the air pump to stop inflating. S3. Place the base pressure plate in the groove of the flexible airbag so that the side wall of the base pressure plate is in full contact or in contact with the side wall of the groove; S4. Place the flexible airbag in the model box so that the bottom of the flexible airbag is located on the foundation. At the same time, make the side wall of the inflated flexible airbag contact or fit with the inner wall of the model box, and make one end of the base pressure plate contact with the inner wall of the model box. Press the base pressure plate so that the bottom surface of the base pressure plate contacts the foundation. S5. Place the model box in the placement position inside the reaction frame, with the top of the flexible airbag close to the reaction frame. Turn on the vertical load device, move the load applying part of the vertical load device downward, observe the load applying part of the vertical load device, and turn off the vertical load device when the load applying part of the vertical load device contacts the top surface of the foundation bearing plate. S6. Calculate the additional stress σ1 given to the foundation by the surrounding soil of the simulated foundation according to the buried depth h1 of the simulated foundation: ， Among them, ρ1 is the density of the soil sample, h1 is the foundation depth to be simulated; A preset stress σ1 is set through the stress controller, the stress controller and the air pump are turned on, and the flexible airbag continues to be inflated. When the gas stress sensor senses that the gas stress in the flexible airbag has reached the preset stress σ1, the gas stress sensor feeds back a signal to the stress controller, and the stress controller controls the air pump to shut down and stop inflating the flexible airbag. At this time, the flexible airbag swells and gives a thrust to the reaction frame, the reaction frame gives a reverse thrust to the flexible airbag, and the flexible airbag gives a thrust to the foundation. The thrust given by the flexible airbag to the foundation is the additional force given to the foundation by the covering soil around the foundation to be simulated, and the additional stress given to the foundation by the covering soil around the foundation to be simulated is σ1; S7. Turn on the vertical load device, and the load applying portion of the vertical load device continues to move downward. The load applying portion of the vertical load device pushes the foundation pressure plate to continue to move downward. The downward movement of the foundation pressure plate is observed. When the foundation pressure plate contacts the foundation, turn off the vertical load device and reset the displacement sensor at the same time. S8. Set the preset load of the load controller to F1, turn on the load controller and the vertical load device, and the load applying part of the vertical load device applies the vertical load F1 to the foundation bearing plate. The settlement distance L1 of the foundation bearing plate can be measured by the displacement sensor; S9, gradually increasing the preset load to F2...Fn, repeating step S8 each time the preset load is increased, and measuring the corresponding settlement distances of the foundation bearing plate to be L2...Ln respectively, until the settlement distance of the foundation bearing plate reaches the relevant requirements in the specification, and then ending the test; S10. When it is necessary to simulate the influence of different foundation burial depths on the indoor flat plate load test, repeat steps S1-S9; S11. When it is necessary to change a different soil sample to perform an indoor flat plate load test under the influence of foundation burial depth, repeat steps S1-S10.

7. The indoor plate load test method considering the influence of foundation depth according to claim 6 is characterized in that: In step S8, the camera may capture the deformation of the soil sample.

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