A method for constructing a test system for simulating a clayey soil squeezed branch pile

Abstract

The application discloses a kind of construction methods of simulating cohesive soil quality extrusion branch disc pile test system, comprising S100: preparation homogeneous cohesive soil, guarantee that cohesive soil is at optimum moisture content and is layered equal thickness and fills;S200: at the design pile position, steel casing is struck for hole positioning;S300: uniform slow rotary drilling dry hole operation and soil are taken until the design elevation of pile bottom;S400: carry out extrusion operation;S500: using computer vision equipment in-depth drilling detects disc cavity soil integrity;S600: using long auger is placed in drill hole;S700: the steel reinforcement cage that is bound in advance is lowered to hole bottom;S800: using self-compacting concrete of design strength pours pile foundation model.The application uses self-compacting concrete of design strength to pour pile foundation model, the coarse aggregate particle size of self-compacting concrete is not more than 10-20cm, and the slump is not less than 180mm, and vibration is avoided to avoid bubble or void of concrete pouring in small space, after curing, test can be carried out, realizes indoor extrusion branch disc pile stress mechanism test.

Description

Technical Field

[0001] This invention belongs to the field of pile foundation construction technology, and more specifically, relates to a method for constructing a test system for simulating cohesive soil expansion and spur piles. Background Technology

[0002] Pouring concrete to form irregularly shaped piles with multiple bearing plates or supports has the following main characteristics: Due to the squeezing and expanding effect of the support machine, the soil at the upper and lower ends of the support plate is compacted, increasing the soil's compression modulus and shear strength, similar to applying prestress to the soil. Its physical and mechanical properties are higher than those of the undisturbed soil, improving the bearing capacity of the soil at the end of the support plate and increasing the bearing capacity of a single pile. This allows for shorter pile lengths, fewer piles, and savings in concrete and steel, achieving green, energy-saving, and environmentally friendly practices. Moreover, the position of the support plate can be adjusted according to the soil layer distribution, fully utilizing the role of high-bearing-capacity soil layers.

[0003] Experimental studies on the expansion and compression pile technology generally employ in-situ field tests and indoor model tests. In-situ field tests are typically conducted on engineering piles or test piles, which have high single pile bearing capacity, large load capacity, high testing costs, long testing cycles, and generally lack repeatability. Indoor model tests, on the other hand, usually involve prefabricating a model of the expansion and compression pile and embedding it in the soil for loading tests. The geometric similarity ratio is generally very small, and the model size is small to facilitate pre-embedding and operation. However, this method cannot reflect the compaction effect of the expansion and compression on the soil during construction. Yet, the expansion and compaction of the soil is one of the core factors for improving the bearing capacity of the expansion and compression pile foundation.

[0004] For indoor soil simulations, artificially filled sand is difficult to achieve the requirements of medium-dense and dense sand, and the risk of borehole collapse during expansion is extremely high, leading to test failure. Therefore, indoor tests are generally based on cohesive soil, but the optimum moisture content and optimum compaction energy of cohesive soil need to be determined by experiments. During the experiment, it is essential to ensure that each layer of the same soil material is filled evenly, which is also the difficulty of soil filling in indoor experiments.

[0005] Therefore, in general, the existing indoor model testing methods in China cannot meet the requirements of restoring the actual construction technology and procedures on site, and cannot realize the production of large-scale models. There are drawbacks and shortcomings in the study of the actual stress mechanism of the extruded and expanded support pile. Summary of the Invention

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method for constructing a simulated cohesive soil expansion and compression pile test system. Based on the soil density requirements for filling, homogeneous cohesive soil is prepared indoors. Using the same compaction function, the soil is filled to the designed thickness. A steel casing is installed at the designed pile location for hole positioning. Dry drilling is performed using a uniform, slow rotary drill, and soil is removed until the designed pile bottom elevation is reached. Expansion and compression operations are then carried out, with the rotation angle controlled to ensure a superposition rate of no less than 10%. Simultaneously, computer vision technology is used to detect the integrity of the soil within the pile cavity. After drilling to the designed hole depth and completing the soil removal operation, a pile foundation model is poured using self-compacting concrete of designed strength. The coarse aggregate particle size of the self-compacting concrete should not exceed 10–20 cm, the slump should not be less than 180 mm, and vibration is used to avoid air bubbles or voids in small-space concrete pouring. After curing for 28 days, the test can be conducted, realizing an indoor test of the stress mechanism of expansion and compression piles.

[0007] To achieve the above objectives, the present invention provides a method for constructing a test system for simulating cohesive soil expansion piles, comprising the following steps: S100: Prepare homogeneous cohesive soil, ensure that the cohesive soil is at the optimal moisture content and lay it in layers of equal thickness. According to the filling requirements of soil layer compaction, each time based on the same compaction function until the design thickness is reached. S200: Steel casings are installed at the designed pile locations for hole positioning. The inclination deviation of the casings must not exceed 1%. S300: Uniform, slow rotary drilling dry hole formation and soil removal until the design elevation of the pile bottom is reached, and the deviation of the pile hole inclination shall not exceed 1%; S400: Perform extrusion expansion operations and install an angle scale on the steel casing to control the rotation angle and ensure that the stacking rate is not less than 10%; S500: Computer vision equipment is used to deeply inspect the integrity of the soil in the borehole. For soil falling on the bottom surface of the cavity, a small-diameter hydraulic extrusion and expansion machine is used to re-extrude until the integrity of the cavity meets the design requirements and there is no loose soil on the bottom surface of the cavity. S600: A long auger is placed inside the borehole. The ground is manually rotated to provide torque, cutting the sediment at the bottom of the hole. The drill rod is then lifted to complete a single soil removal operation. This process is repeated multiple times until the designed hole depth is reached to complete the soil removal operation. S700: Lower the pre-tied steel cage to the bottom of the hole, ensuring that the steel cage is vertical and centered, and use the surface casing to control the distance between the bottom of the cage and the bottom of the hole. S800: The pile foundation model is cast using self-compacting concrete of the designed strength, and vibration is used to avoid air bubbles or voids in the concrete in small spaces. The test can be carried out after curing for 10-50 days.

[0008] Furthermore, in step S300, a small-diameter auger drilling electric device is used to complete the rotary dry drilling operation.

[0009] Furthermore, the small-diameter spiral drilling electric device includes an engine and a drill bit assembly fixedly connected thereto. The drill bit assembly includes a drill rod, spiral blades surrounding the drill rod, and a manganese steel drill bit disposed at the end of the drill rod. After aligning the pile position, start the engine to drive the drill bit assembly to drill into and out of the soil. Once the controlled depth is reached, stop drilling, lift the drill bit, and check the quality of the hole. After drilling to the predetermined depth, the drill must be run idle at the bottom of the hole to clear the soil. When lifting the drill rod, it must not be bent. Any soil scattered on the ground during drilling should be removed and transported away in a timely manner.

[0010] Furthermore, in step S400, a small-diameter hydraulic extrusion expander is lowered to the design elevation to complete the extrusion expansion operation.

[0011] Furthermore, the small-diameter hydraulic extrusion and expansion support machine includes a connecting device, a power device, and an extrusion and expansion device; The extrusion device is lowered to the elevation set in the inner cavity of the hole, and the extrusion device is opened under the power of the hydraulic cylinder, and the extruded soil is expanded to form a cavity. After the extrusion and expansion are completed, the oil is returned and the extrusion and expansion device is retracted. The angle control disc rotates once. The above extrusion and expansion process is repeated in sequence. After rotating 180 degrees, the extrusion and expansion process of one disc cavity is completed.

[0012] Furthermore, after the small-diameter spiral drilling electric equipment completes the hole-forming operation and lifts it upwards, it is replaced by a small-diameter hydraulic extrusion and expansion support machine for vertical hole entry; A crane is used to suspend the small-diameter hydraulic extrusion and expansion machine at the designed plate position elevation to carry out the extrusion and expansion operation. The quality of the cavity is controlled by angle control disc equipment and drilling imaging detection equipment.

[0013] Furthermore, the angle control disc device serves as a benchmark for controlling the single rotation angle of the extrusion equipment during the extrusion process.

[0014] Furthermore, the angle control disc device controls the small-diameter hydraulic extrusion expansion disc machine to rotate a certain angle each time, ensuring that the superposition rate is not less than 10%.

[0015] Furthermore, in the self-compacting concrete pile foundation model, the coarse aggregate particle size of the self-compacting concrete does not exceed 10-20cm.

[0016] Furthermore, in the self-compacting concrete pile foundation model, the slump of the self-compacting concrete is not less than 180mm.

[0017] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The method of the present invention involves preparing homogeneous cohesive soil in the room according to the soil density requirements for filling. Based on the same compaction function, the soil is filled to the design thickness. A steel casing is installed at the design pile position for hole positioning. Dry drilling is carried out at a uniform and slow speed, and soil is removed until the design elevation of the pile bottom is reached. Expansion operation is carried out, and the rotation angle is controlled to ensure that the superposition rate is not less than 10%. At the same time, computer vision technology is used to detect the integrity of the soil in the cavity. The soil is cleaned after drilling to the design hole depth. The pile foundation model is poured with self-compacting concrete of the design strength. The coarse aggregate particle size of the self-compacting concrete should not exceed 10-20cm, the slump should not be less than 180mm, and vibration is used to avoid air bubbles or voids in the concrete pouring in small spaces. After curing for 28 days, the test can be carried out, realizing the indoor force mechanism test of the expansion support pile.

[0018] 2. The method of the present invention uses a small-diameter spiral drilling electric equipment to complete the hole-forming operation, and a small-diameter hydraulic extrusion expansion support machine as the extrusion expansion cavity-forming equipment to complete the extrusion expansion cavity-forming operation; auxiliary devices such as angle control disc equipment and drilling imaging detection equipment are used to ensure the extrusion expansion quality and integrity of the cavity.

[0019] 3. In the method of the present invention, after the auger drilling equipment completes the hole-forming operation, it is lifted and moved out, and then replaced with a small-diameter hydraulic extrusion and expansion support machine for vertical hole entry. A crane is used to suspend it at the designed support elevation for extrusion and expansion operations. The angle control disc equipment and the drilling imaging detection equipment serve as auxiliary devices for cavity quality control and assurance. The angle control disc equipment controls the rotation angle of the small-diameter hydraulic extrusion and expansion support machine each time, ensuring that the overlap rate is not less than 10%.

[0020] 4. In the method of the present invention, the drilling imaging detection equipment must have a high-definition camera with sufficient pixels, focal length, and night vision function in order to observe the integrity of the extrusion cavity.

[0021] 5. In the method of the present invention, during the extrusion process, the extrusion device is lowered to the set elevation of the cavity inside the hole, and the extrusion device is opened under the power of the hydraulic cylinder, and the soil is extruded to form a cavity; after the extrusion is completed, the oil is returned to retract the extrusion device, the angle control disc rotates once, and the above extrusion process is repeated, and the cycle is repeated in sequence. When the rotation is 180 degrees, the extrusion process of one cavity is completed.

[0022] 6. The method of the present invention serves as a benchmark for controlling the single rotation angle of the extrusion equipment during the extrusion process. The rotation angle is kept constant each time to ensure that the extrusion overlap rate forms a complete disk cavity, and to avoid incomplete disk cavities caused by excessive single rotation angle or insufficient overlap rate. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the construction process of a simulated cohesive soil expansion and slab pile test system according to an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating the process of simulating the expansion and displacement pile test in cohesive soil according to an embodiment of the present invention; Figure 3 This is a front view of the small-diameter spiral drilling electric device in an embodiment of the present invention; Figure 4 This is an isometric view of the small-diameter spiral drilling electric device in an embodiment of the present invention; Figure 5 This is a front view of the cavity expansion device for small-diameter support piles in an embodiment of the present invention; Figure 6 This is a top view of the cavity expansion device for small-diameter pile foundations in an embodiment of the present invention; Figure 7 This is a schematic diagram of the angle control disk device in an embodiment of the present invention; Figure 8 This is a schematic diagram of the soil integrity detection in the cavity according to an embodiment of the present invention.

[0024] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-soil preparation and layered filling, 2-casing installation, 3-hole drilling, 4-cavitation expansion, 5-cavity inspection, 6-hole cleaning, 7-lowering the reinforcing cage, 8-concrete pouring, 9-small-diameter spiral drilling electric equipment, 10-small-diameter hydraulic expansion support machine, 11-angle control panel equipment, 12-drilling imaging inspection equipment, 13-start handle, 14-fuel filler port, 15-enlarged heat dissipation hole, 16-oil filler port, 17-manganese steel drill bit, 18-engine, 19-fuel tank, 20-handle, 21-gearbox, 22-connecting device, 23-expansion device, 24-power unit, 25-angle control panel, 26-scale line. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides a construction method for a simulated cohesive soil expansion and spur pile test system, comprising the following steps: S100: Prepare homogeneous cohesive soil, ensure that the cohesive soil is at the optimal moisture content and lay it in layers of equal thickness. According to the filling requirements of soil layer compaction, each time based on the same compaction function until the design thickness is reached. S200: Steel casings shall be installed at the designed pile locations for hole positioning, and the inclination deviation of the casings shall not exceed 1%; S300: A specially designed small-diameter auger drilling electric equipment is used for uniform, slow-speed dry drilling and soil removal until the design elevation of the pile bottom is reached. The deviation of the pile hole inclination shall not exceed 1%. S400: A small-diameter hydraulic extrusion expansion machine is used to lower the machine to the design elevation for extrusion expansion operations. An angle scale is installed at the steel casing to control the rotation angle and ensure that the stacking rate is not less than 10%. S500: High-definition camera with night vision function is used to go deep into the borehole to check the integrity of the soil in the cavity. For the soil that has fallen on the bottom surface of the cavity, a small-diameter hydraulic extrusion and expansion machine is used to re-extrude until the integrity of the cavity meets the design requirements and there is no loose soil on the bottom surface of the cavity. S600: A long auger is placed inside the borehole. The ground is manually rotated to provide torque, cutting the sediment at the bottom of the hole. The drill rod is then lifted to complete a single soil removal operation. This process is repeated multiple times until the designed hole depth is reached to complete the soil removal operation. S700: Lower the pre-tied steel cage to the bottom of the hole, ensuring that the steel cage is vertical and centered, and use the surface casing to control the distance between the bottom of the cage and the bottom of the hole. S800: Use self-compacting concrete of design strength to pour pile foundation model. The coarse aggregate particle size of self-compacting concrete should not exceed 10-20cm, the slump should not be less than 180mm, and vibration should be used to avoid air bubbles or voids in small space concrete pouring. Tests can be carried out after 28 days of curing.

[0027] Among them, such as Figure 3 and Figure 4 As shown, during the process implementation, a small-diameter spiral drilling electric device 9, capable of dry-operation hole forming, is developed to complete the hole forming operation. A small-diameter hydraulic extrusion expansion support machine 10 is used as the extrusion expansion cavity forming equipment to complete the cavity forming operation. Auxiliary devices such as an angle control disc device 11 and a drilling imaging detection device 12 are used to ensure the quality and integrity of the cavity extrusion expansion. After the spiral drilling device 9 completes the hole forming operation, it is lifted and moved out, and then replaced by the small-diameter hydraulic extrusion expansion support machine 10 for vertical hole insertion. A crane is used to suspend it at the designed disc elevation for extrusion expansion. The angle control disc device 11 and the drilling imaging detection device 12 serve as auxiliary devices for cavity forming quality control and assurance. The angle control disc device 11 controls the rotation angle of the small-diameter hydraulic extrusion expansion support machine 10 each time, ensuring that the superposition rate is not less than 10%. Figure 8 As shown, the borehole imaging detection device 12 must have a high-definition camera with sufficient pixels, focal length, and night vision function in order to observe the integrity of the extrusion cavity.

[0028] Specifically, such as Figure 2As shown, in the embodiments of the present invention, the process flow includes 1-8, wherein, soil preparation and layered filling 1 corresponds to S100: homogeneous cohesive soil is prepared using a crushing device, ensuring that the cohesive soil is at its optimal moisture content and is laid in layers of equal thickness. According to the filling requirements of soil layer compaction, each time is based on the same compaction function until the design thickness is reached; casing installation 2 corresponds to S200: steel casings are installed at the designed pile positions for hole positioning. The inclination deviation of the casings must not exceed 1%; hole drilling operation 3 corresponds to S300: a specially designed small-diameter spiral drilling electric device is used for uniform and slow rotary drilling dry hole drilling and soil removal until the designed elevation of the pile bottom is reached. The inclination deviation of the pile hole must not exceed 1%. Expansion cavity formation 4 corresponds to S400: a small-diameter hydraulic expansion support machine is used to lower to the design elevation for expansion operation, and an angle scale is installed at the steel casing to facilitate control of the rotation angle and ensure the superposition rate. The superposition rate must not be less than 10%. Drill Hole Inspection 5 (corresponding to S500): High-definition video surveillance equipment with night vision capability is used to penetrate deep into the borehole to inspect the integrity of the soil in the drill hole. For any fallen soil on the bottom surface of the drill hole, a small-diameter hydraulic extrusion and expansion machine 10 should be used for re-extrusion until the integrity of the drill hole meets the design requirements and there is no loose soil on the bottom surface of the drill hole. Hole Cleaning Operation 6 (corresponding to S600): A long auger is placed inside the borehole, and the ground is manually rotated to provide torque to cut the sediment at the bottom of the hole. The drill rod is then lifted to complete a single soil cleaning operation. This is repeated multiple times until the designed hole depth is reached, and the soil cleaning operation is finally completed. Lowering the Reinforcing Cage 7 (corresponding to S700): The pre-tied reinforcing cage is lowered to the bottom of the hole, ensuring that the reinforcing cage is vertical and centered. The distance between the bottom of the cage and the bottom of the hole is controlled by using a surface casing. For pile foundation model casting 8 corresponding to S800: After lowering the steel cage, use self-compacting concrete of the design strength to cast the pile foundation model. The coarse aggregate particle size of the self-compacting concrete should not exceed 10~20cm, the slump should not be less than 180mm, and it should be vibrated appropriately to avoid air bubbles or voids in the concrete in small spaces. Curing should be carried out for 10-50 days, for example, after 28 days, the test can be carried out.

[0029] The cavity detection 5 uses a high-definition camera with night vision capability to collect image data deep inside the borehole, such as... Figure 8 As shown, this is to check whether the soil in the cavity is intact.

[0030] like Figure 3 and Figure 4 As shown, this embodiment of the invention provides a small-diameter spiral drilling electric device 9, which includes: an engine 18 and a drill bit assembly fixedly connected thereto.

[0031] The drill bit assembly includes: a drill rod, spiral blades surrounding the drill rod, and a manganese steel drill bit 17 located at the end of the drill rod. First, the drilling rig is positioned and kept stable. To accurately control the drilling depth, a control scale is installed on the frame or pipe for observation and recording during construction. After aligning the pile position, the machine is started to drill and remove soil. Once the controlled depth is reached, drilling is stopped, the drill bit is lifted, and the hole quality is checked. After reaching the predetermined depth, the drill must be idled at the bottom of the hole to clear the soil before stopping rotation. The drill rod must not be bent when lifting it. Soil scattered on the ground during drilling must be promptly removed and transported away.

[0032] like Figure 5 and Figure 6 As shown, this embodiment of the invention provides a cavity-forming and expanding device for small-diameter pile bearings, which includes a connecting device 22, a power device 24, and an expanding device 23. During the expanding process, the expanding device 23 is lowered to the set elevation of the pile bearing cavity inside the hole. Driven by the power device 24 of the hydraulic cylinder, the expanding device 23 is opened, and the soil is expanded to form a cavity. After the expanding process is completed, the expanding device 23 is retracted by returning oil, and the angle control disc device 11 rotates once. The above expanding process is repeated, and the cycle continues. After rotating 180 degrees, the expanding process of one pile bearing cavity is completed.

[0033] like Figure 7 As shown, this embodiment of the invention provides an angle control disk device 11, including an angle control disk 25 and scale lines 26. The angle control disk 25 serves as a scale for controlling the single rotation angle of the extrusion device during the extrusion process. Each rotation angle remains constant to ensure the extrusion overlap rate forms a complete disk cavity, avoiding incomplete disk cavities due to excessively large single rotation angles or insufficient overlap rate. During extrusion, the extrusion is completed sequentially by referring to the prompts on the annular scale lines 26 until a 180-degree rotation completes the extrusion of a complete disk cavity.

[0034] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for constructing a test system for simulating cohesive soil expansion and spur piles, characterized in that, Includes the following steps: S100: Prepare homogeneous cohesive soil, ensure that the cohesive soil is at the optimal moisture content and lay it in layers of equal thickness. According to the filling requirements of soil layer compaction, each time based on the same compaction function until the design thickness is reached. S200: Steel casings are installed at the designed pile locations for hole positioning. The inclination deviation of the casings must not exceed 1%. S300: Uniform, slow rotary drilling dry hole formation and soil removal until the design elevation of the pile bottom is reached, and the deviation of the pile hole inclination shall not exceed 1%; S400: Perform extrusion expansion operations and install an angle scale on the steel casing to control the rotation angle and ensure that the stacking rate is not less than 10%; S500: Computer vision equipment is used to deeply inspect the integrity of the soil in the borehole. For soil falling on the bottom surface of the cavity, a small-diameter hydraulic extrusion and expansion machine is used to re-extrude until the integrity of the cavity meets the design requirements and there is no loose soil on the bottom surface of the cavity. S600: A long auger is placed inside the borehole. The ground is manually rotated to provide torque, cutting the sediment at the bottom of the hole. The drill rod is then lifted to complete a single soil removal operation. This process is repeated multiple times until the designed hole depth is reached to complete the soil removal operation. S700: Lower the pre-tied steel cage to the bottom of the hole, ensuring that the steel cage is vertical and centered, and use the surface casing to control the distance between the bottom of the cage and the bottom of the hole. S800: The pile foundation model is cast using self-compacting concrete of the design strength, and vibration is used to avoid air bubbles or voids in the concrete in small spaces. The test can be carried out after curing for 10-50 days. In step S300, a small-diameter auger drilling electric device (9) is used to complete the rotary dry drilling operation; The small-diameter spiral drilling electric equipment (9) includes an engine (18) and a drill bit assembly fixedly connected thereto. The drill bit assembly includes a drill rod, spiral blades surrounding the drill rod, and a manganese steel drill bit (17) set at the end of the drill rod. After aligning the pile position, start the engine (18) to drive the drill bit assembly to drill and exit the soil. After reaching the controlled depth, stop drilling, lift the drill, and check the hole quality. After drilling to the predetermined depth, the drill must be idled at the bottom of the hole to clear the soil. Stop rotating the drill rod and do not bend it when lifting the drill rod. Soil scattered on the ground during the drilling process should be removed and transported in time. In step S400, a small-diameter hydraulic extrusion and expansion support machine (10) is lowered to the design elevation to complete the extrusion and expansion operation. The small-diameter hydraulic extrusion and expansion support machine (10) includes a connecting device (22), a power device (24), and an extrusion and expansion device (23). The extrusion and expansion device (23) is lowered to the elevation set in the hole cavity. Driven by the power device (24) of the hydraulic cylinder, the extrusion and expansion device (23) is opened, and the soil is extruded and expanded to form a cavity. After the extrusion and expansion is completed, the oil is returned to retract the extrusion and expansion device (23), and the angle control disc device (11) rotates once. The above extrusion and expansion process is repeated in sequence. After rotating 180 degrees, the extrusion and expansion process of one cavity is completed. After the small-diameter spiral drilling electric equipment (9) completes the hole-forming operation and lifts it out, it is replaced by a small-diameter hydraulic extrusion and expansion support machine (10) for vertical hole entry; a crane is used to suspend the small-diameter hydraulic extrusion and expansion support machine (10) at the designed plate position elevation to carry out the extrusion and expansion operation; The cavity quality is controlled by the angle control disc device (11) and the borehole imaging detection device (12).

2. The construction method of a simulated cohesive soil expansion pile test system according to claim 1, characterized in that, The angle control disc device (11) serves as a benchmark for controlling the single rotation angle of the extrusion equipment during the extrusion process.

3. The construction method of a simulated cohesive soil expansion pile test system according to claim 2, characterized in that, The angle control disc device (11) controls the small-diameter hydraulic extrusion expansion disc machine (10) to rotate a certain angle each time to ensure that the superposition rate is not less than 10%.

4. A method for constructing a simulated cohesive soil expansion pile test system according to any one of claims 1-3, characterized in that, In the self-compacting concrete pile foundation model, the coarse aggregate particle size of the self-compacting concrete does not exceed 10-20cm.

5. A method for constructing a simulated cohesive soil expansion pile test system according to any one of claims 1-3, characterized in that, In the self-compacting concrete pile foundation model, the slump of the self-compacting concrete is not less than 180mm.

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