Vacuum negative pressure loading uplift pile bearing capacity model test device and test method

Abstract

The invention relates to the technical field of pile foundation engineering detection, and discloses a vacuum negative pressure loading uplift pile bearing capacity model test device, which comprises an observation model assembly, an uplift pile bearing capacity test assembly, an uplift pile bearing capacity test assembly, an uplift pile bearing capacity test assembly, an uplift pile bearing capacity test assembly and an uplift pile bearing capacity test assembly, and is characterized in that the observation model assembly comprises a model box, a soil sample and a simulated groundwater layer, sensor groups are uniformly distributed in the soil sample and are used for collecting soil pressure, pore water pressure and temperature in the soil sample; strain gauges are uniformly distributed on the model pile and used for collecting strain of the model pile; the vacuum negative pressure system is used for generating tensile force; and the traction system is used for transmitting the tensile force generated by the vacuum negative pressure system to the observation model assembly and pulling the model pile in the vertical direction to carry out an uplift bearing capacity experiment of the model pile. The tensile force generated by vacuum negative pressure is used for testing the uplift bearing capacity of the pile, the uplift bearing capacity of the pile under various complex working conditions can be tested, and even the influence of soil bodies with different properties and different water contents on the uplift bearing capacity of the pile foundation when underground water exists can be simulated.

Description

Technical Field

[0001] The invention relates to the technical field of pile foundation engineering detection, and in particular to a vacuum negative pressure loaded pull-out pile bearing capacity model test device and a test method. Background Art

[0002] When the groundwater resources in the construction site are rich, the groundwater will generate upward buoyancy on the building. At this time, if the gravity of the upper building is less than the buoyancy of the water, the building will move upward as a whole or in part, and the building is prone to damage. Therefore, it is necessary to set up anti-pull piles to resist the buoyancy generated by groundwater, and the quality inspection of anti-pull piles is particularly important.

[0003] At present, there are two main methods for testing the pull-out bearing capacity of pile foundations. One is a single pile vertical pull-out static load test, in which a jack is used to apply force to the reaction piles on both sides of the pile foundation, so that the pull-out piles are subjected to an upward pull. The other is to directly provide an upward pull to the pull-out piles through large lifting equipment. Both testing methods can be used for field testing and model testing. The field test results are reliable, but the testing cycle is long, the testing cost is high, and the area occupied is large. When the actual geological conditions are poor, the field test method is not suitable. Although the existing model test method has overcome some of the problems existing in the field test, it requires personnel to operate large equipment, which poses certain safety hazards, and the measurement results of large equipment have large errors. Indoor testing still requires a large site, which consumes a lot of manpower and material resources. Summary of the invention

[0004] The purpose of the present invention is to provide a vacuum negative pressure loaded pull-out pile bearing capacity model test device and test method, which adopts the vacuum negative pressure method to provide tension and carry out pile foundation pull-out bearing capacity detection, does not need to use large-scale equipment, and the test method is simple and safe; on the basis of considering the influence of groundwater, it can simulate the pile foundation pull-out bearing process under various working conditions, and provide guidance for the research and design of related pull-out pile model tests; in order to deal with the problems existing in the existing pile foundation pull-out bearing capacity detection method, at the same time meet the detection needs of pile foundation construction under complex geological conditions.

[0005] The present invention provides the following technical solutions:

[0006] A vacuum negative pressure loading pull-out pile bearing capacity model test device, comprising:

[0007] The observation model component includes a model box, in which soil samples and simulated groundwater layers are layered and placed, and model piles are vertically placed in the soil samples; a sensor group is evenly distributed in the soil sample, and the sensor group is used to collect soil pressure, pore water pressure and temperature parameters in the soil sample;

[0008] Vacuum negative pressure system, used to generate tension;

[0009] The pulling system is used to transmit the pulling force generated by the vacuum negative pressure system to the observation model component, pull the model pile in the vertical direction, and perform a pull-out bearing capacity test on the model pile.

[0010] According to some embodiments, the simulated groundwater layer is achieved by isolating the soil sample from the water layer through two layers of upper and lower waterproof films; heating rods are evenly distributed around the soil sample; the sensor group includes a soil pressure sensor, a pore water pressure sensor, a temperature sensor and a corresponding data acquisition instrument; a strain gauge is attached to the model pile body and transmits the strain to the strain acquisition instrument.

[0011] According to some embodiments, at least one layer of vertical partitions for adjusting the volume of the soil sample is provided in the model box.

[0012] According to some embodiments, the material of the model box is selected from tempered glass; the material of the partition is selected from resin glass.

[0013] According to some embodiments, the pulling system includes a telescopic rod, which is horizontally fixed on the inner and outer sides above the box body on one side of the model box. A fixed pulley is provided at the end of the telescopic rod. One end of the cable is connected to the vacuum negative pressure system outside the model box, and the other end is passed through two fixed pulleys and connected to the top of the model pile.

[0014] According to some embodiments, the telescopic rod is provided with a plurality of sets of screw holes for adjusting the position of the fixed pulley, and the upper edge of the model box is provided with two rows of screw holes for fixing the telescopic rod and fixing the partition.

[0015] According to some embodiments, the vacuum negative pressure system includes a negative pressure cylinder, a piston and a vacuum pump. A spring is provided at the bottom of the negative pressure cylinder, a barometer is provided on the piston, the barometer is connected to the interior of the negative pressure cylinder, and the top of the piston is connected to one end of the cable.

[0016] According to some embodiments, the piston includes a butyl rubber plug that wraps around the periphery and bottom of the acrylic piston plate; the vacuum pump evenly extracts air through a plurality of vertical exhaust holes evenly distributed on the piston.

[0017] In a second aspect, the present invention provides a test method for the above-mentioned vacuum negative pressure loading pull-out pile bearing capacity model test device, which comprises the following steps:

[0018] S1: According to the test observation requirements, it can be selected whether to use a partition to change the amount of soil samples around the model pile, display the cross-section of the soil samples around the model pile, and facilitate the observation of the overall displacement and local displacement of the soil samples around the model pile during the pull-out process;

[0019] S2: After the bottom soil sample is loaded into the model box, a simulated groundwater layer is laid, and then the model piles with strain gauges arranged are buried in the soil. At the same time, soil pressure sensors, pore water pressure sensors and temperature sensors are evenly buried around the model piles, and each sensor and strain gauge is connected to the corresponding data acquisition instrument respectively; the soil is heated by the preset heating rods around the model box to raise the temperature of the soil sample to the required temperature;

[0020] S3: Use the telescopic rod inside the model box to place the fixed pulley just above the model pile, and use the telescopic rod outside the model box to place the fixed pulley just above the vacuum negative pressure system, use a cable to connect the model pile and the piston, and connect the barometer to the inside of the negative pressure cylinder;

[0021] S4: After checking the stability and air tightness of the test device, use a vacuum pump to extract the air in the negative pressure cylinder, so that the external air pressure exerts downward pressure on the piston, and this pressure is converted into the tension on the model pile through the cable and the fixed pulley; the test loading method is controllable, and the tension can be controlled by controlling the air pressure of the vacuum negative pressure system, so as to achieve graded loading or cyclic loading;

[0022] S5: Start the test, observe the data acquisition instrument, grasp the changes in pressure, strain and settlement in real time, and fully simulate the pile foundation pull-out process; after the test, first unload the negative pressure cylinder, unload the pressure, and complete the pile foundation pull-out model test.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The vacuum negative pressure loading pull-out pile bearing capacity model test device provided by the present invention has the characteristics of simple operation, safety and short test cycle. The use of the device to conduct the pile foundation pull-out bearing capacity test does not require the use of large equipment, jacks and reaction frames, which not only saves manpower and material resources, but also reduces the errors and operational errors that may occur when researchers operate large equipment, thereby reducing the risk of safety accidents.

[0025] 2. The test device provided by the present invention directly displays the cross section of the soil through a transparent material model box, and the position of the partition can be adjusted according to the test requirements, so as to visually observe the displacement changes of the soil at different radii centered on the model pile. In the field construction of pile foundations, the soil conditions are often complex and changeable, and the device of the present invention fully meets the needs of researchers, and can directly adjust the type of soil sample and moisture content in the test; it can also use a heating rod to change the temperature of the soil, and use a waterproof film to simulate groundwater, so that the model test is more in line with the actual situation, thereby obtaining more reliable test results.

[0026] 3. The test device provided by the present invention uses an acrylic piston plate and a butyl rubber plug. Under the premise of ensuring the airtightness of the negative pressure cylinder, the external atmospheric pressure is used to generate pressure on the acrylic piston plate, and then the pressure is converted into the tension on the model pile through the fixed pulley, thereby eliminating the need to use a jack or rely on external loads to provide tension.

[0027] 4. The screw holes reserved on the upper part of the model box and the telescopic rod in the device of the present invention facilitate researchers to conduct pull-out bearing capacity tests on pull-out piles of different sizes and forms, and can also conduct pull-out bearing capacity tests considering pile group effects.

[0028] 5. The strain gauges arranged on the model pile body and the soil pressure sensors, pore water pressure sensors and temperature sensors evenly distributed around the pile can help researchers monitor the required data in real time, thereby helping researchers to understand the entire development process of pile foundation pull-out bearing.

[0029] 6. In the device of the present invention, the spring arranged at the bottom of the negative pressure cylinder can ensure the safety of the test and prevent the acrylic piston plate from moving down instantly when the model pile is pulled out of the soil, thus causing damage to the test device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is an overall schematic diagram of a vacuum negative pressure loaded pull-out pile bearing capacity model test device provided in an embodiment of the present invention.

[0031] Figure 2 It is a top view of a vacuum negative pressure loaded pull-out pile bearing capacity model test device provided in an embodiment of the present invention.

[0032] Figure 3 Schematic diagram of a model box provided by an embodiment of the present invention.

[0033] Figure 4 Schematic diagram of a pulling system provided by an embodiment of the present invention.

[0034] Figure 5 Schematic diagram of a vacuum negative pressure system provided in an embodiment of the present invention.

[0035] In the figure: 1-soil sample, 2-tempered glass model box, 3-model pile, 4-fixed pulley, 5-telescopic rod, 6-cable, 7-hook, 8-heating rod, 9-waterproof film, 10-micrometer, 11-reference beam, 12-soil pressure collector, 13-pore water pressure collector, 14-temperature collector, 15-soil pressure sensor, 16-pore water pressure sensor, 17-temperature sensor, 18-strain gauge, 19-vacuum pump, 20-acrylic piston plate, 21-butyl rubber plug, 22-spring, 23-barometer, 24-negative pressure cylinder, 25-exhaust hole, 26-resin glass partition, 27-buckle, 28-screw hole, 29-nut and bearing, 30-rubber tube, 31-flat pipe clamp, 32-hexagonal bolt, 33-strain collector, 34-adhesive. DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. In addition, unless otherwise clearly specified and limited, the terms "set", "install", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] The present invention proposes a vacuum negative pressure loaded pull-out pile bearing capacity model test device and test method, which utilizes the vacuum negative pressure system and pulling system of the test device to provide an upward pulling force for the model pile. When the vacuum pump extracts the air inside the negative pressure cylinder, the atmospheric pressure outside the negative pressure cylinder generates a downward pressure on the acrylic piston plate, and then the pressure is converted into the pulling force on the model pile through the cable and fixed pulley in the device, so that the pile foundation pull-out bearing capacity model test can be carried out. The test method does not rely on large equipment, jacks and reaction frames to provide pulling force, and is easy and safe to operate. It also solves the problem of large floor space occupied by indoor tests and inconvenience in providing pulling force for the model pile indoors. The use of a waterproof film and a heating rod can also comprehensively simulate the influence of temperature and groundwater on the pull-out bearing capacity of the pile foundation. The test device and test method provide a more accurate, safe and reliable testing means for the study of the pull-out bearing capacity of the pile foundation.

[0039] The present invention will be further described below in conjunction with the accompanying drawings.

[0040] Example 1

[0041] like Figure 1-Figure 5 As shown, the present embodiment provides a vacuum negative pressure loaded pull-out pile bearing capacity model test device, including a soil sample 1, a tempered glass model box 2, a model pile 3, a fixed pulley 4, a telescopic rod 5, a cable 6, a hook 7, a heating rod 8, a waterproof film 9, a micrometer 10, a reference beam 11, a soil pressure collector 12, a pore water pressure collector 13, a temperature collector 14, a soil pressure sensor 15, a pore water pressure sensor 16, a temperature sensor 17, a strain gauge 18, a vacuum pump 19, an acrylic piston plate 20, a butyl rubber plug 21, a spring 22, a barometer 23, a negative pressure cylinder 24, an air extraction hole 25, a resin glass partition 26, a buckle 27, a screw hole 28, a nut and a bearing 29, a rubber tube 30, a flat pipe clamp 31, a hexagonal bolt 32, a strain collector 33, and an adhesive 34.

[0042] The soil sample 1 is loaded into the tempered glass model box 2 in layers. In order to simulate the influence of groundwater buoyancy in the model test, after the soil sample 1 is loaded into the bottom layer of the tempered glass model box 2, a layer of waterproof film 9 is put in, and then another layer of waterproof film 9 is put in after water is added. The waterproof film 9 is to prevent the soil particles in the soil sample 1 from directly contacting the water in the waterproof film 9, which may affect the model test results. After the waterproof film 9 is placed, the soil sample 1 is continued to be loaded. While the soil sample 1 is compacted in layers, the soil pressure sensor 15, pore water pressure sensor 16, temperature sensor 17 and strain gauge 18 are placed vertically around the model pile 3 and the pile body. Then, the heating rod 8 is arranged around the tempered glass model box 2. After the internal devices of the tempered glass model box 2 are placed, the reference beam 11 is placed on the left and right sides of the model pile 3, and a micrometer 10 is connected to each of them to calibrate whether the model pile 3 is placed vertically and the inclination of the model pile 3 during the pull-out process.

[0043] The test device includes telescopic rods 5 and fixed pulleys 4 facing both sides, and a single telescopic rod 5 and fixed pulley 4 facing the vacuum negative pressure system. Figure 4 As shown, the fixed pulley 4 and telescopic rod 5 facing the vacuum negative pressure system are the same as those facing the model pile 3. The telescopic rod 5 and the fixed pulley 4 are assembled together using nuts and bearings 29, and then the telescopic rod 5 and the fixed pulley 4 are fixed to the upper row of screw holes 28 reserved in the tempered glass model box 2 using hexagonal bolts 32. Among them, the telescopic rod 5 is adjusted to telescope through the screw holes 28 and the hexagonal bolts 32. The buckle 27 is fixed through the second row of screw holes 28 and the hexagonal bolts 32 reserved in the tempered glass model box 2, and then the resin glass partition 26 is fixed using the buckle 27. The tempered glass model box 2 and the resin glass partition 26 are both made of transparent materials, which are used to observe the displacement changes of the soil at different radii with the model pile 3 as the center.

[0044] Apply adhesive 34 around and on the bottom of the acrylic piston plate 20, and then place the acrylic piston plate 20 into the butyl rubber plug 21 until the adhesive 34 firmly bonds the acrylic piston plate 20 and the butyl rubber plug 21. Place the bonded acrylic piston plate 20 and butyl rubber plug 21 vertically into the negative pressure cylinder 24, and the three form a closed space. To ensure air tightness, the butyl rubber plug 21 is provided with a three-layer outer ring, and its diameter is 3mm larger than the diameter of the negative pressure cylinder 24. The barometer 23 is placed on the acrylic piston plate 20 and connected to the inside of the negative pressure cylinder 24 to monitor the system air pressure and air tightness. Use a rubber tube 30 to cover the air extraction hole 25, and then use a flat tube clamp 31 to clamp the rubber tube 30 and the air extraction hole 25 to ensure the air tightness inside the negative pressure cylinder 24.

[0045] The soil pressure sensor 15, pore water pressure sensor 16, temperature sensor 17 and strain gauge 18 are respectively connected to the soil pressure collector 12, pore water pressure collector 13, temperature collector 14 and strain collector 33 through wires. The vacuum pump 19 is connected to the rubber tube 30 for vacuuming.

[0046] This embodiment also provides a test method for testing the pull-out bearing capacity of a pile foundation using the above-mentioned vacuum negative pressure loaded pull-out pile bearing capacity model test device, comprising the following steps:

[0047] 1) First, according to the test observation requirements, it can be selected whether to use the resin glass partition 26 to adjust the amount of the soil sample 1 around the model pile, or to display the cross section of the soil sample 1 around the model pile, so as to help observe the overall displacement and local displacement of the surrounding soil sample 1 during the pull-out process of the model pile 3;

[0048] 2) After placing the bottom soil sample 1 into the tempered glass model box 2, a waterproof film 9 is laid, and after adding a large amount of water to simulate the groundwater in the natural environment, another waterproof film 9 is laid (the size of the waterproof film 9 can be slightly larger than the tempered glass model box 2, and vaseline can also be applied on the edge to ensure the separation of the soil layer and the water layer), and then fill the soil and bury the model pile 3 with the strain gauge 18 arranged, and evenly bury the soil pressure sensor 15, pore water pressure sensor 16 and temperature sensor 17 with the model pile 3 as the center; use the preset heating rods 8 around the tempered glass model box 2 to heat the soil body and raise the temperature of the soil sample 1 to the required temperature;

[0049] 3) Using the telescopic rod 5 inside the tempered glass model box 2 to place the fixed pulley 4 just above the model pile 3, using the telescopic rod 5 outside the tempered glass model box 2 to place the fixed pulley 4 just above the vacuum negative pressure tension system, using the cable 6 and the hook 7 to connect the model pile 3 and the acrylic piston plate 20, the barometer 23 is connected to the inside of the cylindrical tempered glass tube 24, monitoring the air pressure and air tightness, and ensuring the normal operation of the vacuum negative pressure system;

[0050] 4) After the stability and air tightness inspection of the test device is completed, the air in the negative pressure cylinder 24 is extracted by a vacuum pump 19 to make the internal air pressure lower than the external air pressure. The external air pressure exerts downward pressure on the acrylic piston plate 20, and the pressure is converted into the tension on the model pile 3 through the cable 6 and the fixed pulley 4. The test loading mode is controllable, and the tension can be controlled by controlling the air pressure of the vacuum negative pressure system, so as to realize graded loading or cyclic loading.

[0051] 5) During the test, observe the soil pressure collector 12, pore water pressure collector 13, temperature collector 14, strain collector 33 and dial gauge 10, grasp the changes of pressure, strain and settlement in real time, and fully simulate the pull-out process of the pile foundation. If a resin glass partition 26 is used for observation, be careful to apply vaseline around the resin glass partition 26 to prevent the soil sample 1 and water in the tempered glass model box 2 from being lost. After the test, first open the valve of the negative pressure cylinder 24, let in air, and recycle the equipment after the pressure is unloaded to complete the pile foundation pull-out model test.

[0052] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A vacuum negative pressure loading pull-out pile bearing capacity model test device, characterized in that: include: The observation model component includes a model box, in which soil samples and simulated groundwater layers are layered and placed, and model piles are vertically placed in the soil samples; a sensor group is evenly distributed in the soil sample, and the sensor group is used to collect soil pressure, pore water pressure and temperature parameters in the soil sample; Vacuum negative pressure system, used to generate tension; The pulling system is used to transmit the pulling force generated by the vacuum negative pressure system to the observation model component, pull the model pile in the vertical direction, and perform a pull-out bearing capacity test on the model pile.

2. The vacuum negative pressure loading pull-out pile bearing capacity model test device according to claim 1, characterized in that: The simulated groundwater layer is achieved by isolating the soil sample from the water layer through two layers of waterproof films, upper and lower. Heating rods are evenly distributed around the soil sample. The sensor group includes a soil pressure sensor, a pore water pressure sensor, a temperature sensor and a corresponding data acquisition instrument. The strain gauge is attached to the model pile body and transmits the strain to the strain acquisition instrument.

3. The vacuum negative pressure loading pull-out pile bearing capacity model test device according to claim 2 is characterized in that: At least one layer of vertical partition for adjusting the volume of the soil sample is arranged in the model box.

4. The vacuum negative pressure loading pull-out pile bearing capacity model test device according to claim 3 is characterized in that: The material of the model box is selected from tempered glass; the material of the partition is selected from resin glass.

5. The vacuum negative pressure loading pull-out pile bearing capacity model test device according to claim 4 is characterized in that: The pulling system includes a telescopic rod, which is horizontally fixed on the inner and outer sides above the box body on one side of the model box. A fixed pulley is provided at the end of the telescopic rod. One end of the cable is connected to the vacuum negative pressure system outside the model box, and the other end is passed through two fixed pulleys and connected to the top of the model pile.

6. The vacuum negative pressure loading pull-out pile bearing capacity model test device according to claim 5, characterized in that: The telescopic rod is provided with a plurality of sets of screw holes for adjusting the position of the fixed pulley, and the upper edge of the model box is provided with two rows of screw holes for fixing the telescopic rod and the partition.

7. The vacuum negative pressure loading pull-out pile bearing capacity model test device according to claim 6, characterized in that: The vacuum negative pressure system includes a negative pressure cylinder, a piston and a vacuum pump. A spring is provided at the bottom of the negative pressure cylinder, a barometer is provided on the piston, the barometer is connected to the inside of the negative pressure cylinder, and the top of the piston is connected to one end of the cable.

8. The vacuum negative pressure loading pull-out pile bearing capacity model test device according to claim 7, characterized in that: The piston comprises a butyl rubber plug which wraps around the periphery and the bottom surface of the acrylic piston plate; the vacuum pump evenly draws air through a plurality of vertical air extraction holes evenly distributed on the piston.

9. A test method for the vacuum negative pressure loading pull-out pile bearing capacity model test device according to claim 7, characterized in that: The following steps are involved: S1: According to the test observation requirements, it can be selected whether to use a partition to change the amount of soil samples around the model pile, display the cross-section of the soil samples around the model pile, and facilitate the observation of the overall displacement and local displacement of the soil samples around the model pile during the pull-out process; S2: After the bottom soil sample is loaded into the model box, a simulated groundwater layer is laid, and then the model piles with strain gauges arranged are buried in the soil. At the same time, soil pressure sensors, pore water pressure sensors and temperature sensors are evenly buried around the model piles, and each sensor and strain gauge is connected to the corresponding data acquisition instrument respectively; the soil is heated by the preset heating rods around the model box to raise the temperature of the soil sample to the required temperature; S3: Use the telescopic rod inside the model box to place the fixed pulley just above the model pile, and use the telescopic rod outside the model box to place the fixed pulley just above the vacuum negative pressure system, use a cable to connect the model pile and the piston, and connect the barometer to the inside of the negative pressure cylinder; S4: After checking the stability and air tightness of the test device, use a vacuum pump to extract the air in the negative pressure cylinder, so that the external air pressure exerts downward pressure on the piston, and this pressure is converted into the tension on the model pile through the cable and the fixed pulley; the test loading method is controllable, and the tension can be controlled by controlling the air pressure of the vacuum negative pressure system, so as to achieve graded loading or cyclic loading; S5: Start the test, observe the data acquisition instrument, grasp the changes in pressure, strain and settlement in real time, and fully simulate the pile foundation pull-out process; after the test, first unload the negative pressure cylinder, unload the pressure, and complete the pile foundation pull-out model test.

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