Pile driving centrifuge test device with different installation and extraction methods and operation method thereof

Abstract

The present invention discloses a driven pile centrifuge test device with different installation and extraction methods, comprising: a support system, a pile driving system, a pile-soil system and a measurement and collection system. The present invention also provides an operation method of the above-mentioned driven pile centrifuge test device with different installation and extraction methods. The present invention can carry out geotechnical centrifuge tests on the penetration of driven piles in different installation methods and the extraction of driven piles in different extraction methods, and provides an effective test device and method for the study of the dynamic response of the pile-soil interaction during the entire penetration process and the extraction process of the driven pile. The deformation characteristics of the pile-soil during the penetration and extraction process can be directly observed by a high-speed camera or a digital camera, and the extraction and penetration tests can be carried out separately.

Description

Technical Field

[0001] The present invention relates to a pile driving centrifuge test device with different installation and extraction modes. The present invention also relates to an operation method of the above-mentioned pile driving centrifuge test device with different installation and extraction modes. Background Art

[0002] Traditional driven pile installation methods generally include hammer penetration, vibration penetration and static pressure penetration. At present, the research on the penetration and installation process of driven piles mainly uses pile driving analysis software based on wave equations and field test record collection and analysis. However, the pile driving analysis software based on wave equations has limitations because it cannot analyze problems such as fluid-solid coupling during the penetration process of piles, and field tests are restricted by factors such as acquisition equipment and high economic costs. Therefore, in the process of conducting relevant research, numerical analysis and indoor tests are generally used for detailed research and comparison, so as to obtain the relationship between the bearing capacity of driven piles during the installation process and the size of the piles, the properties of the soil, etc. However, due to the limitations of numerical technology development, the currently developed numerical analysis of pile driving has not yet been commercialized and applied industrially, and the indoor test of 1g gravity has certain irrationality in the test results due to the influence of size effect. The geotechnical centrifuge can overcome the influence of size effect and greatly reduce the cost of field tests. Moreover, due to the high controllability of the test environment, relevant tests can be carried out many times, so that effective comparative data can be obtained, which provides a basis for more detailed and in-depth research. At present, there is a lack of relevant geotechnical centrifuge test instruments to carry out experimental research equipment and methods on the dynamic response of piles and soil during the penetration process of driven piles with different installation methods.

[0003] Moreover, the pile hammers and model piles of traditional research equipment do not have very precise and stable guidance, and the pile hammers often need to be very large in size to maintain the force, so the accuracy is insufficient and the force direction often deviates. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a centrifuge test device for driving piles with different installation and extraction methods, which provides a more intuitive indoor test research method for the pile-soil interaction and the dynamic response of the soil during the penetration of the driven piles, and makes the relevant regular responses of the penetration process close to the on-site through the geotechnical centrifuge, and can effectively guide the movement of the pile hammer and the pile body through structural settings, so that the pile driving process is more accurate, so as to obtain accurate test data. The technical problem to be solved by the present invention also includes providing an operation method of the above-mentioned centrifuge test device for driving piles with different installation and extraction methods.

[0005] To this end, the present invention provides a pile driving centrifuge test device with different installation and extraction methods, including: a support system, a pile driving system, a pile-soil system and a measurement and collection system.

[0006] Support system: including vertical support system and pile frame support system. The vertical support system includes threaded rigid columns, vertical outer support frames, vertical inner support frames and bottom rigid plates. The vertical support system is used to support the entire test model and is connected to the corresponding device of the centrifuge. At the same time, it provides a support platform for the pile frame in the model. The vertical outer support frame is movably connected to the threaded rigid columns and is lifted and lowered by the vertical bracket lifting motor; the pile frame support system is used to support the pile frame, including upper pile frame outer support, upper pile frame inner and outer supports, lower pile frame inner support, lower pile frame outer support, upper pile frame back support and lower pile frame back support. The pile frame support system ensures that the pile frame remains stable during the piling process and the geotechnical centrifuge test.

[0007] Pile-soil system: includes model piles and model boxes. A pile cap is fixed on the top of the model pile to protect the head of the model pile during the penetration process. Monitoring elements of physical and mechanical variables are pasted on the pile body. The model box is a semi-cylindrical box with a closed lower part and an open upper part. The semi-circular part is composed of high-strength and high-rigidity steel plates. The box body is provided with drainage holes. The semi-circular section of the model box is composed of high-strength resin transparent plates. Soil is arranged in the model box. A lifting motor is fixed under the fixed bracket. The lifting motor is sleeved on the threaded rigid column. The lifting motor drives the nut to rotate to achieve lifting and lowering on the threaded rigid column, thereby controlling the height of the fixed bracket.

[0008] Centrifuge system: including a centrifuge. The support system, the full-life loading system for driven piles, and the pile-soil system are fixedly installed in the test cabin of the centrifuge. The movement of the centrifuge applies hypergravity to the test model, which accelerates the time of fluid-solid coupling and the process of change in the hypergravity environment.

[0009] Measuring system: including soil monitoring system and pile monitoring system. The soil monitoring system includes soil monitoring element 17. The pile monitoring system includes pile monitoring element. The soil monitoring element tests the initial stress and strain of soil sample, pore pressure state and corresponding physical and mechanical parameters during the piling process and after installation. The pile monitoring element can collect physical and mechanical parameters such as deformation stress of the pile.

[0010] The piling system includes a piling frame, piling equipment and a penetration and extraction power device. The piling frame is connected to the vertical support system through a piling frame support system. The piling equipment includes a pile hammer guide rail, a pile driving guide rail and a penetration and extraction power device. The extraction power device 11 is equipped with a motor system and a pile hammer. A pile hammer pad is installed at the bottom of the pile hammer. The extraction method adopts vibration extraction or static load extraction. A hammer pad is arranged at the lower end of the extraction device. The hammer pad conducts electricity to generate electromagnetic attraction. The magnetic force of the hammer pad is controlled by changing the current. The pile cap is made of a material that can be magnetically attracted. After the hammer pad is energized, it is magnetically attracted to the pile cap. The pile cap, pile pad, hammer pad and model pile are fixed as a whole during the extraction process.

[0011] Preferably, the pile driving hammer guide rail includes a vertical hole maintained on four sides, the pile driving hammer is placed in the vertical hole, a driven pile guide rail is arranged in the center of the pile driving hammer guide rail, both sides of the driven pile guide rail are connected to the inner side wall of the pile driving hammer guide rail by vertical ribs, the driven pile guide rail has side openings on the upper and lower sides, the pile driving hammer has an I-shaped cross-section, the pile driving hammer has a downward hammering end, the cross-section of the hammering end matches the driven pile guide rail, the hammering end is placed in the driven pile guide rail, the upper and lower narrow parts of the pile driving hammer are located at the side openings, and the upper and lower wide parts of the pile driving hammer are arranged close to the inner wall of the pile driving hammer guide rail.

[0012] The present invention provides an operating method of a pile driving centrifuge test device with different installation and extraction methods, comprising the following steps:

[0013] First, determine the size and layout of each system of the test device, and test and analyze the penetration and extraction process of large-diameter open pile foundation in in-situ saturated clay. The geotechnical centrifuge is 150g, the in-situ size of the pile is 8m in diameter, 80m in length, and 9cm in wall thickness. The saturated clay is marine saturated clay, and the fluid is seawater. The size of the model pile is set to 5.34cm in diameter, 53.34cm in length, and 0.6mm in wall thickness. The pile body is evenly and symmetrically arranged with 10 grating fiber points on each side. The grating fiber earth pressure micro-boxes and piezometers in the soil are symmetrically arranged in 3 rows respectively. The two test elements are arranged at intervals, with a total of 12 rows, 8 in each row along the height direction. The size of the model box is 1.5m in diameter and 1.0m in height. There are 10 drainage holes evenly arranged along the height direction of the model box, 10 evenly arranged along the diameter direction of the bottom, and 15 rows arranged along the arc direction. The length of the pile frame is 1.2m and the width is 0.25. m, the pile hammer guide rail and the driven pile guide rail are evenly and symmetrically distributed on the pile frame, and the pile frame is symmetrically fixed in the vertical support system along the length direction;

[0014] 2. Install the support system, pile-soil system, measurement system and centrifuge system;

[0015] 3. Pile driving system: The model pile is penetrated into the soil by hammering, and the extraction method is static pressure. The corresponding pile hammer and extraction equipment are selected, both of which are servo-controlled;

[0016] 4. Carry out hammer penetration test, collect monitoring data through wireless acquisition system, record hammer penetration process through high-definition high-speed computer, and control hammer penetration of pile hammer through wireless servo control;

[0017] 5. After the penetration is completed, a long-term bearing performance test is carried out. The servo control is used to hold the pile hammer equipment and the pile head tightly. After the required test time, the data is always collected during the period. The servo control is converted to the pull-out mode and a pull-out test is carried out. Relevant data is collected through the wireless collection system, and the pull-out process is recorded with a high-speed camera.

[0018] Preferably, when hammer penetration is adopted, a pile pad needs to be laid on the model pile; when static pressure and vibration penetration are adopted, a pile pad is not required; when vibration penetration is adopted, the pile cap of the model pile and the pile hammer need to be fixed.

[0019] Preferably, the vertical support system and the pile frame support system are made of 8#B-12#B high-strength I-beams anchored by rivets, and the pile frame support system and the pile frame are also anchored by rivets.

[0020] Technical effects of the present invention:

[0021] 1) The present invention can carry out geotechnical centrifuge tests of driven piles in different installation modes and different extraction modes, and provides an effective test device and method for studying the dynamic response of pile-soil interaction during the entire process of driven pile penetration and extraction;

[0022] 2) The deformation characteristics of the pile and soil during the penetration and extraction process can be directly observed by a high-speed camera or a digital camera, and the extraction and penetration tests can be carried out separately;

[0023] 3) The device provides a more intuitive indoor test research method for pile-soil interaction and soil dynamic response during the penetration process of driven piles, and makes the relevant regular responses of the penetration process close to the on-site ones through the geotechnical centrifuge;

[0024] 4) Through structural settings, the movement of the pile hammer and pile body is effectively guided to make the piling process more accurate and obtain accurate test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic cross-sectional view of the structure of a pile driving centrifuge test device with different installation and removal methods provided by the present invention.

[0026] Figure 2 for Figure 1Side view of.

[0027] Figure 3 It is a top view of the vertical support system of the present invention.

[0028] Figure 4 It is a top view of the pile driver support system of the present invention.

[0029] Figure 5 Based Figure 1 Schematic diagram of the transverse section of the pile hammer guide, pile driving guide and pile hammer.

[0030] Figure 6 for Figure 5 Schematic diagram of the top view of the pile hammer.

[0031] Figure 7 for Figure 6 Side view of.

[0032] Figure 8 It is a schematic diagram of the structural relationship between the pile driving hammer, the pile driving guide rail and the model pile, in which the pile driving hammer has not yet entered the pile driving guide rail.

[0033] Fig. 9 It is a schematic diagram of the structural relationship between the pile driving hammer, the driven pile guide rail and the model pile, in which the pile driving hammer penetrates deep into the driven pile guide rail. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The same parts are represented by the same reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "bottom surface" and "top surface", "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0035] Reference Figure 1-4 As shown, the pile driving centrifuge test device with different installation and extraction methods provided by the present invention includes: a support system, a pile driving system, a pile-soil system and a measurement and collection system.

[0036] Support system: includes vertical support system and pile frame support system. The vertical support system includes threaded rigid column 1, vertical outer support frame 2, vertical inner support frame 3 and bottom rigid plate 24. The vertical support system is used to support the entire test model and is connected to the corresponding device of the centrifuge. At the same time, it provides a support platform for the pile frame in the model. The vertical outer support frame 2 is movably connected to the threaded rigid column 1, and the lifting and lowering are controlled by the vertical bracket lifting motor 29; the pile frame support system is used to support the pile frame, including upper pile frame outer support 4, upper pile frame inner and outer supports 5, lower pile frame inner support 6, lower pile frame outer support 7 and upper pile frame back support 26 and lower pile frame back support 27. The pile frame support system ensures that the pile frame remains stable during the piling process and the geotechnical centrifuge test.

[0037] Pile-soil system: includes a model pile 15 and a model box 18. A pile cap 14 is fixed to the top of the model pile 15. The pile cap 14 protects the head of the model pile during the penetration process. Monitoring elements of physical and mechanical variables (pile body strain stress, etc., such as pile body monitoring element 16 and grating optical fiber monitoring element) are pasted on the pile body. The model box 18 is a semi-cylindrical box with a closed lower part and an open upper part. The semi-circular part is composed of a high-strength and high-rigidity steel plate. The box body is provided with drainage holes 19. The semi-circular section of the model box 18 is composed of a high-strength resin transparent plate 28. Soil 20 is arranged in the model box 18. A lifting motor 22 is fixed below the fixed bracket 21. The lifting motor 22 is sleeved on the threaded rigid column 1. The lifting motor 22 drives the nut to rotate to achieve lifting on the threaded rigid column 1, thereby controlling the height 21 of the fixed bracket.

[0038] Centrifuge system: including a centrifuge. The support system, the full-life loading system for driven piles, and the pile-soil system are fixedly installed in the test cabin of the centrifuge. The movement of the centrifuge applies hypergravity to the test model, which accelerates the time of fluid-solid coupling and the process of change in the hypergravity environment.

[0039] Measuring system: including soil monitoring system and pile monitoring system. The soil monitoring system includes soil monitoring element 17, and the pile monitoring system includes pile monitoring element 16. The soil monitoring element 17 tests the initial stress and strain of the soil sample, the pore pressure state, and the corresponding physical and mechanical parameters during the piling process and after the installation is completed. The pile monitoring element 16 can collect physical and mechanical parameters such as deformation stress of the pile body;

[0040] Its characteristics are: the pile driving system includes a pile driving frame 9, pile driving equipment and a penetration and extraction power device 11. The pile driving equipment is a mechanism for applying force to the pile, which includes a pile hammer, a vibrating hammer and a static pressure device, etc. The pile driving frame 9 is made of a special rigid steel plate. The pile driving frame 9 is connected to the vertical support system through a pile driving frame support system. The pile driving frame 9 is marked with a ruler. The ruler on the pile driving frame 9 enables the tester to effectively grasp the data of the pile entering during the test so as to combine it with other data to form a data model. The pile driving equipment includes a pile driving hammer guide rail 9, a pile driving guide rail 10 and a penetration and extraction power device 11. The extraction power device 11 is equipped with a motor system and a pile driving hammer. The penetration and extraction power device 11 can select a hammer hammer, a vibrating hammer and a static pressure hammer according to the different penetration methods and extraction methods. The hammer hammer can adopt a hydraulic hammer, and the power adopts a diesel hydraulic Or electromagnetic impact method, a pile hammer pad 12 is installed at the bottom of the pile hammer; the extraction method adopts vibration extraction or static load extraction, and a hammer pad is arranged at the lower end of the extraction device. The hammer pad conducts electricity to generate electromagnetic attraction, and the magnetic force of the hammer pad is controlled by changing the current. The pile cap is made of a material that can be magnetically attracted. After the hammer pad is energized, it is magnetically attracted to the pile cap. The pile cap, pile pad, hammer pad and model pile are fixed together during the extraction process. The fixing method adopts automatic clamping equipment for fixing to ensure the stability of the piling process. This fixing method is within the scope of the prior art.

[0041] Reference Figure 1 , 2 , Figure 5 , Figure 6 , Figure 7 , Figure 8 As shown, in order to enable the pile hammer and the model pile to be driven into the soil more accurately, the pile driving hammer guide rail 9 includes a vertical hole 91 maintained on four sides, and the pile driving hammer 30 is placed in the vertical hole. A pile driving guide rail 10 is arranged in the center of the pile driving hammer guide rail 9. The two sides of the pile driving guide rail 10 are connected to the inner wall of the pile driving hammer guide rail 9 by vertical ribs 92. The upper and lower sides of the pile driving guide rail 10 have side openings 93. The cross-section of the pile driving hammer 30 is I-shaped. The pile driving hammer 30 has a downward hammering end 301, and the cross-section of the hammering end 301 matches the pile driving guide rail 10. The hammering end 301 is placed in the pile driving guide rail 10, and the upper and lower narrow parts 302 of the pile driving hammer 30 are located at the side openings 93. The upper and lower wide parts 303 of the pile driving hammer 30 are arranged close to the inner wall of the pile driving hammer guide rail 9. In the above structure, the I-shaped pile hammer 30 is accurately guided, and the pile driving guide rail 10 and the hammer end 301 are arranged at the center of gravity of the pile hammer 30, so as to ensure the volume and weight of the pile hammer 30 and ensure that the hammering position is below the center of gravity of the pile hammer 30, so as to be more efficient and accurate.

[0042] Reference Figure 1-4 As shown, the operating method of the above-mentioned pile driving centrifuge test device with different installation and extraction methods provided by the present invention comprises the following steps:

[0043] First, determine the size and layout of each system of the test device. The test intends to analyze the penetration and extraction process of large-diameter open pile foundation in in-situ saturated clay. The geotechnical centrifuge is 150 g, the in-situ size of the pile is 8 m in diameter, 80 m in length, and 9 cm in wall thickness. The saturated clay is marine saturated clay, and the fluid is seawater. The size of the model pile 15 is set to 5.34 cm in diameter, 53.34 cm in length, and 0.6 mm in wall thickness. The pile body is evenly and symmetrically arranged with 10 grating fiber points on each side. The grating fiber earth pressure micro-boxes and piezometers in the soil are symmetrically arranged in 3 rows respectively. The two test elements are arranged at intervals, with a total of 12 rows, 8 in each row along the height direction. The size of the model box is 1.5 m in diameter and 1.0 m in height. There are 10 drainage holes evenly arranged along the height direction of the model box, 10 evenly arranged along the diameter direction of the bottom, and 15 rows arranged along the arc direction. The length of the pile frame 8 is 1.2 m and the width is 0.25 m, the pile hammer guide rail 9 and the pile driving guide rail 10 are evenly and symmetrically distributed on the pile frame 9, and the pile frame 8 is symmetrically fixed in the vertical support system along the length direction;

[0044] 2. Install the support system, pile-soil system, measurement system and centrifuge system; wherein the vertical support system and pile frame support system are made of 8#B-12#B high-strength I-steel anchored by rivets, and the pile frame support system and the pile frame are also anchored by rivets. The height of the threaded rigid column 1 is 1.8 m and the diameter is 1.2 cm.

[0045] 3. Piling system: The model pile is penetrated into the soil by hammering, and is pulled out by static pressure. The corresponding pile hammer and pulling equipment are selected, both of which are servo-controlled. When hammering is used for penetration, the model pile needs to be laid with a pile pad 13; when static pressure and vibration penetration are used, the pile pad 13 is not required; when vibration penetration is used, the pile cap 14 of the model pile and the pile hammer need to be fixed.

[0046] 4. Carry out hammer penetration test, collect monitoring data through wireless acquisition system, record hammer penetration process through high-definition high-speed computer, and control hammer penetration of pile hammer through wireless servo control;

[0047] 5. After the penetration is completed, a long-term bearing performance test is carried out. The servo control is used to hold the pile hammer equipment and the pile head tightly. After the required test time, the data is always collected during the period. The servo control is converted to the pull-out mode, and a pull-out test is carried out. The relevant data is collected through the wireless acquisition system, and the pull-out process is recorded with a high-speed camera. The wireless acquisition system can collect data in real time without interfering with the test device, and the pull-out process is recorded by a high-speed camera to better observe and verify the theoretical model.

[0048] The above is only a preferred embodiment 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, some 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 centrifuge test device for driving piles with different installation and extraction methods, comprising: Support system, piling system, pile-soil system and measurement and collection system, Support system: including vertical support system and pile frame support system. The vertical support system includes threaded rigid columns, vertical outer support frames, vertical inner support frames and bottom rigid plates. The vertical support system is used to support the entire test model and is connected to the corresponding device of the centrifuge. At the same time, it provides a support platform for the pile frame in the model. The vertical outer support frame is movably connected to the threaded rigid columns and is controlled by the vertical bracket lifting motor. The pile frame support system is used to support the pile frame, including upper pile frame outer support, upper pile frame inner support, lower pile frame inner support, lower pile frame outer support, upper pile frame back support and lower pile frame back support. The pile frame support system ensures that the pile frame remains stable during the piling process and geotechnical centrifuge test. Pile-soil system: including model piles and model boxes. A pile cap is fixed on the top of the model pile to protect the head of the model pile during the penetration process. Monitoring elements of physical and mechanical variables are pasted on the pile body. The model box is a semi-cylindrical box with a closed lower part and an open upper part. The semi-circular part is composed of a high-strength and high-rigidity steel plate. The box body is provided with drainage holes. The semi-circular section of the model box is composed of a high-strength resin transparent plate. Soil is arranged in the model box. A lifting motor is fixed under the fixed bracket. The lifting motor is sleeved on the threaded rigid column. The lifting motor drives the nut to rotate to achieve lifting on the threaded rigid column and control the height of the fixed bracket. Centrifuge system: including a centrifuge. The support system, the full-life loading system for driven piles, and the pile-soil system are fixedly installed in the test cabin of the centrifuge. The movement of the centrifuge applies hypergravity to the test model, which accelerates the time of fluid-solid coupling and the process of change in the hypergravity environment. Measurement system: including soil monitoring system and pile monitoring system. The soil monitoring system includes soil monitoring elements, and the pile monitoring system includes pile monitoring elements. The soil monitoring elements test the initial stress and strain of soil samples, the pore pressure state, and the corresponding physical and mechanical parameters during the piling process and after installation. The pile monitoring elements can collect physical and mechanical parameters such as deformation stress of the pile body. The pile driving system comprises a pile driving frame, pile driving equipment and a driving and pulling out power equipment, the pile driving frame is connected to the vertical supporting system through the pile driving frame supporting system, the pile driving equipment comprises a pile hammer guide rail, a pile driving guide rail and a driving and pulling out power equipment, the pulling out power equipment is equipped with a motor system and a pile hammer, and a pile hammer pad is installed at the lower part of the pile hammer; the pulling out method adopts vibration pulling out or static load pulling out, a hammer pad is arranged at the lower end of the pulling out equipment, the hammer pad is electrically conductive to generate electromagnetic attraction, the magnetic force of the hammer pad is controlled by changing the current, the pile cap is made of a material that can be magnetically attracted, the hammer pad is magnetically attracted to the pile cap after being energized, and the pile cap, pile pad, hammer pad and model pile are fixed as a whole during the pulling out process; The pile driving hammer guide rail comprises a vertical hole with four sides for maintenance, the pile driving hammer is placed in the vertical hole, a driven pile guide rail is arranged in the center of the pile driving hammer guide rail, both sides of the driven pile guide rail are connected to the inner side wall of the pile driving hammer guide rail by vertical ribs, the driven pile guide rail has side openings on the upper and lower sides, the pile driving hammer has an I-shaped cross section, the pile driving hammer has a downward hammering end, the cross section of the hammering end matches the driven pile guide rail, the hammering end is placed in the driven pile guide rail, the upper and lower narrow parts of the pile driving hammer are located at the side openings, and the upper and lower wide parts of the pile driving hammer are arranged close to the inner wall of the pile driving hammer guide rail; The vertical support system and the pile frame support system are made of 8#B-12#B high-strength I-beams anchored by rivets, and the pile frame support system and the pile frame are anchored by rivets.

2. The centrifuge test device for driving piles with different installation and removal methods according to claim 1, characterized in that: A ruler is marked on the pile driving frame.

3. An operating method of the pile driving centrifuge test device with different installation and extraction methods as claimed in claim 1, characterized in that: The following steps are involved: First, determine the size and layout of each system of the test device, and test and analyze the penetration and extraction process of large-diameter open pile foundation in in-situ saturated clay. The geotechnical centrifuge is 150g, the in-situ size of the pile is 8m in diameter, 80m in length, and 9cm in wall thickness. The saturated clay is marine saturated clay, and the fluid is seawater. The size of the model pile is set to 5.34cm in diameter, 53.34cm in length, and 0.6mm in wall thickness. The pile body is evenly and symmetrically arranged with 10 grating fiber points on each side. The grating fiber earth pressure micro-boxes and piezometers in the soil are symmetrically arranged in 3 rows respectively. The two test elements are arranged at intervals, with a total of 12 rows, 8 in each row along the height direction. The size of the model box is 1.5m in diameter and 1.0m in height. There are 10 drainage holes evenly arranged along the height direction of the model box, 10 evenly arranged along the diameter direction of the bottom, and 15 rows arranged along the arc direction. The length of the pile frame is 1.2m and the width is 0.

25. m, the pile hammer guide rail and the driven pile guide rail are evenly and symmetrically distributed on the pile frame, and the pile frame is symmetrically fixed in the vertical support system along the length direction; 2. Install the support system, pile-soil system, measurement system and centrifuge system; 3. Pile driving system: The model pile is penetrated into the soil by hammering, and the extraction method is static pressure. The corresponding pile hammer and extraction equipment are selected, both of which are servo-controlled; 4. Carry out hammer penetration test, collect monitoring data through wireless acquisition system, record hammer penetration process through high-definition high-speed computer, and control hammer penetration of pile hammer through wireless servo control; 5. After the penetration is completed, a long-term bearing performance test is carried out. The servo control is used to hold the pile hammer equipment and the pile head tightly. After the required test time, the data is always collected during the period. The servo control is converted to the pull-out mode and a pull-out test is carried out. Relevant data is collected through the wireless collection system, and the pull-out process is recorded with a high-speed camera.

4. The method for operating the pile driving centrifuge test device with different installation and extraction methods according to claim 3, characterized in that: When hammer penetration is adopted, pile pads need to be laid on the model piles; when static pressure and vibration penetration are adopted, pile pads are not required; when vibration penetration is adopted, the pile cap and pile hammer of the model pile need to be fixed.

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