Prototype pipe pile shaking table test system simulating the action of foundation and superstructure

Abstract

This invention provides a prototype pipe pile shaking table test system for simulating the effects of foundation and superstructure, belonging to the fields of structural engineering, earthquake engineering, and foundation engineering. It includes a shaking table, a prototype pipe pile specimen horizontally arranged on the shaking table surface, a foundation action simulation component, a pile top axial compression simulation component, a pile cap simulation component, and a superstructure dynamic simulation component. The foundation action simulation component is fixed to the shaking table surface and covers the outside of the prototype pipe pile specimen. The pile top axial compression simulation component penetrates the inside of the prototype pipe pile specimen and extends to the outside of the pile bottom. The pile cap simulation component is connected to the top of the prototype pipe pile specimen, and the superstructure dynamic simulation component is positioned above the pile cap simulation component. This invention, using the above-mentioned test system, solves the problems of existing prototype pipe pile shaking table tests, such as large space requirements, high cost of foundation simulation, difficulty in loading real superstructures, inconvenient adjustment of working conditions, difficulty in comprehensively simulating pile-soil-structure interactions, and inability to accurately measure dynamic changes in pile axial force.

Description

Technical Field

[0001] This invention relates to the fields of structural engineering, earthquake engineering and foundation engineering, and in particular to a prototype pipe pile shaking table test system for simulating the action of foundation and superstructure. Background Technology

[0002] Pile foundations are crucial load-bearing and force-transmitting components in building, bridge, and other engineering structures. Under seismic loading, pile foundations simultaneously bear vertical and horizontal loads transmitted from the superstructure, as well as the combined effects of ground motion and pile-soil interaction, making them prone to seismic damage such as cracking, bending, and shearing, which can endanger the overall structural safety. Because pile foundations are located underground, post-earthquake inspection, repair, and reinforcement are difficult and costly. Therefore, conducting research on the seismic performance, dynamic response, and failure mechanisms of prototype pipe piles has significant engineering value.

[0003] Shaking table tests can accurately reflect the stress state, deformation characteristics, and failure process of a structure under seismic loading, making them a reliable testing method for studying the seismic performance of pile foundations. Currently, most shaking table tests on pipe piles use scaled-down models, while shaking table tests on prototype pipe piles or large-size pipe piles remain difficult to implement.

[0004] The prototype pipe piles are long, and simulating foundation constraints and pile-soil interactions using real sand or soil requires a huge test space and a large amount of soil. The test setup is bulky, complex, and costly, and the foundation conditions are difficult to adjust flexibly. Using a real superstructure to simulate pile top loads, constraints, and pile-superstructure interactions further increases the complexity and installation difficulty due to the large mass and size of the superstructure, significantly increasing test costs. Existing test systems cannot simultaneously simulate foundation actions, pile top axial forces, pile cap boundaries, and superstructure dynamic characteristics within a limited space, failing to accurately reflect the true stress and response patterns of the pile-soil-structure interaction under seismic loading. Traditional methods struggle to accurately measure and account for residual axial forces after pile-soil friction and the dynamic changes in axial forces under seismic motion during testing, resulting in insufficient data completeness.

[0005] In summary, existing prototype pipe pile shaking table tests suffer from problems such as large space requirements, high cost of foundation simulation, difficulty in simulating the superstructure, system complexity, inconvenience in adjusting working conditions, and incomplete test data. There is a lack of a shaking table test system suitable for large-size prototype pipe piles that can efficiently simulate the interaction between the foundation and the superstructure. Summary of the Invention

[0006] The purpose of this invention is to provide a prototype pipe pile shaking table test system for simulating the interaction between the foundation and the superstructure. This system solves the problems of existing prototype pipe pile shaking table test systems, such as large space requirements, high cost of foundation simulation, difficulty in loading the real superstructure, inconvenience in adjusting working conditions, difficulty in comprehensively simulating pile-soil-structure interaction, and inability to accurately measure the dynamic changes of pile axial force.

[0007] To achieve the above objectives, the present invention provides a prototype pipe pile shaking table test system for simulating the effects of foundation and superstructure, comprising a shaking table, a prototype pipe pile specimen horizontally arranged on the shaking table surface, a foundation action simulation component, a pile top axial compression simulation component, a pile cap simulation component, and a superstructure dynamic simulation component; the foundation action simulation component is fixed to the shaking table surface and covers the outside of the prototype pipe pile specimen, the pile top axial compression simulation component is inserted inside the prototype pipe pile specimen and extends to the outside of the pile bottom, the pile cap simulation component is connected to the top of the prototype pipe pile specimen, and the superstructure dynamic simulation component is disposed above the pile cap simulation component.

[0008] Preferably, the foundation action simulation component includes a steel sleeve assembly, a preloaded spring, a pressure plate, and friction material; the steel sleeve assembly consists of multiple steel sleeve units arranged at intervals along the axis of the prototype pipe pile specimen, and the steel sleeve units are fixedly connected to the vibration table surface; one end of the preloaded spring is connected to the inner adjustment end plate of the steel sleeve unit, and the other end abuts against the pressure plate, with the pressure plate adhering to the friction material on the side facing the prototype pipe pile specimen.

[0009] Preferably, the steel sleeve unit is a ring-shaped sleeve structure, the adjusting end plate is installed on the side wall of the steel sleeve unit by bolts, and the preload springs are evenly distributed along the circumference of the prototype pipe pile specimen.

[0010] Preferably, the friction material is a surface contact friction pad, which is attached between the pressure plate and the outer wall of the prototype pipe pile specimen.

[0011] Preferably, the pile top axial compression simulation component includes prestressed tendons, prestressed tendon anchorage ends, force sensors, tension beams, and anchorages; the prestressed tendons are inserted through the central hole of the prototype pipe pile specimen, one end is anchored to the pile cap simulation component, and the other end passes through the force sensor and tension beam in sequence, and is connected to the prestressed tendon anchorage end through the anchorages; the force sensor is clamped between the pile bottom and the tension beam.

[0012] Preferably, the tensioning beam is set laterally on the outside of the pile bottom as a prestressing tendon tensioning reaction member; the anchor is sleeved at the end of the prestressing tendon that passes through the tensioning beam.

[0013] Preferably, the foundation simulation component includes a foundation mass block, a two-way slide rail support, a connecting plate, and a flange; the two-way slide rail support is fixed to the vibration table surface and supports the foundation mass block; the flange is fixed to the top of the prototype pipe pile specimen, and the connecting plate is fixed to the end of the foundation mass block; the connecting plate and the flange are connected by bolts and welds.

[0014] Preferably, the bidirectional slide rail support consists of a base, bidirectional guide rails and a slider. The base is fixed to the vibrating table surface, the slider is fixed to the bottom of the foundation mass block, and the foundation mass block can slide in directions parallel and perpendicular to the pile axis.

[0015] Preferably, the superstructure dynamic simulation component includes a superstructure mass block, a one-way slide rail, a rubber support, a viscous damper, and an inertial capacitance device; the guide rail of the one-way slide rail is fixed to the top of the pier mass block, and the slider is fixed to the bottom of the superstructure mass block; the rubber support, the viscous damper, and the inertial capacitance device are respectively connected to the pier mass block and the superstructure mass block at both ends.

[0016] Preferably, the unidirectional slide rail restricts the upper structure mass block to move only relative to the pile cap mass block in a direction perpendicular to the pile axis; the rubber bearing, viscous damper, and inertial capacitance device are arranged in parallel.

[0017] Therefore, the present invention employs the aforementioned prototype pipe pile shaking table test system simulating the action of the foundation and superstructure, and the technical effects are as follows: 1. By arranging the prototype pipe piles horizontally, the vertical space requirements for large-sized specimens are greatly reduced, making installation and testing easier and enabling indoor prototype pipe pile shaking table tests to be carried out.

[0018] 2. The combination of steel sleeves, preloaded springs and friction materials is used to simulate the ground conditions, eliminating the need for real soil and large soil boxes, reducing testing costs, simplifying construction, and facilitating flexible adjustment of different ground conditions.

[0019] 3. By applying axial pressure to the pile top through prestressing and configuring axial force sensors, the actual engineering dead load conditions can be simulated, and the remaining axial force after considering pile-soil friction and the dynamic changes of axial force under ground motion can be accurately measured.

[0020] 4. By adopting a pile cap mass block and a replaceable connection structure, different connection boundaries between the pile and the pile cap are simulated, which is closer to the stress state of real engineering.

[0021] 5. The combination of mass blocks, rubber supports, viscous dampers and inertial capacitance devices is used to simulate the dynamic characteristics of the superstructure. The mass, stiffness, damping and inertia can be flexibly adjusted without the need for a real superstructure. It has a wide range of applications and the device is lightweight.

[0022] 6. It can completely simulate the interaction between pile, soil, and structure within the same system, providing comprehensive test conditions and reliable data, which significantly improves the accuracy and research value of the prototype pipe pile seismic test. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the prototype pipe pile shaking table test system for simulating the effects of the foundation and superstructure according to the present invention. Figure 2 This is a schematic diagram of the foundation action simulation part of the present invention; Figure 3 This is a partial cross-sectional view of the foundation action simulation part of the present invention; Figure 4 This is a schematic diagram of the connection structure between the foundation and the prototype pipe pile of the present invention; Figure 5 This is a schematic diagram simulating the function of the support platform and superstructure of the present invention; Figure 6 This is a partial structural diagram of the upper structure connection part of the present invention; Figure 7 This is a schematic diagram of the prestressed anchorage and axial force measurement section of the pile bottom of the present invention.

[0024] Figure Labels 1. Superstructure mass block; 2. Foundation mass block; 3. Two-way slide rail support; 4. Prototype pipe pile specimen; 5. Steel sleeve assembly; 6. Steel sleeve unit; 7. Preloaded spring; 8. Pressure plate; 9. Friction material; 10. Connecting plate; 11. Flange; 12. One-way slide rail; 13. Rubber support; 14. Viscous damper; 15. Inertia device; 16. Prestressed tendon anchorage end; 17. Force sensor; 18. Tensioning beam; 19. Anchorage. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0027] Example 1 This invention provides a prototype pipe pile shaking table test system for simulating the effects of foundation and superstructure. It aims to solve the problems of large test space requirements, high cost of foundation simulation, difficulty in superstructure simulation, complex test system, and inconvenient implementation of existing prototype pipe pile shaking table systems. It can achieve comprehensive simulation of foundation constraints, pile top axial compression, pile cap connection, and superstructure dynamic effects within a limited test space, and truly reflect the stress and response laws of pile-soil-structure interaction under seismic action.

[0028] like Figure 1As shown, the overall test system includes a superstructure mass block 1, a foundation mass block 2, a bidirectional slide rail support 3, a prototype pipe pile specimen 4, and a steel sleeve assembly 5. The superstructure mass block 1 is positioned above the foundation mass block 2, which is located at one end of the prototype pipe pile specimen 4. The bidirectional slide rail support 3 is located at the bottom of the foundation mass block 2 and fixed to the shaking table surface. The prototype pipe pile specimen 4 is horizontally arranged on the shaking table surface, and the steel sleeve assembly 5 is spaced apart along the axial direction of the specimen 4 on its exterior. This invention arranges the prototype pipe pile specimen 4 horizontally, significantly reducing the requirements for vertical space and installation conditions for large-size prototype pipe piles, facilitating specimen installation, fixation, and testing, and providing a foundation for conducting shaking table tests on prototype pipe piles.

[0029] like Figure 2 , Figure 3 As shown, prototype pipe pile specimen 4 is a precast concrete prototype pipe pile component, horizontally arranged on the vibration table surface. Steel sleeve assemblies 5 are spaced apart along the axial direction on the outside of the specimen. Each steel sleeve assembly 5 consists of multiple circumferential steel sleeve units 6, each fixedly connected to the vibration table surface, capable of moving synchronously with the table surface and transmitting ground vibrations as foundation motion input to the pipe pile specimen. Inside each steel sleeve unit 6, a preload spring 7, a pressure plate 8, and friction material 9 are arranged circumferentially. One end of the preload spring 7 is connected to the adjusting end plate inside the steel sleeve unit 6, and the other end abuts against the pressure plate 8. By adjusting the position of the end plate, the preload of the preload spring 7 can be changed, thereby applying an adjustable radial constraint force to the pipe pile specimen, simulating the lateral constraint effect of different soil layers on the pile body. The pressure plate 8 is used to evenly transmit the force of the preload spring 7 to the surface of the pipe pile. Friction material 9 is fixedly installed on the side of the pressure plate 8 facing the pipe pile, forming surface contact with the outer surface of the pipe pile. When the pile specimen undergoes relative displacement along the axial direction, the friction material 9 generates frictional resistance, simulating the axial friction between the pile and the surrounding soil. By adjusting the preload of the preload spring 7, the parameters of the friction material 9, and the arrangement of the steel sleeve, the pile-soil interaction under different foundation conditions and different pile types can be flexibly simulated.

[0030] like Figure 7As shown, a prestressing tendon is inserted into the central hole of the prototype pipe pile specimen 4. One end of the prestressing tendon is anchored to the pile cap end, and the other end passes through the pile bottom and sequentially through the force sensor 17 and the tension beam 18. An anchor 19 on the outside of the tension beam 18 engages with the anchoring end 16 of the prestressing tendon to achieve locking. The prestressing tendon, the anchoring end 16 of the prestressing tendon, the force sensor 17, the tension beam 18, and the anchor 19 together constitute the prestressing loading and axial force measurement system. Before the test, the prestressing tendon is tensioned, converting the tension force into pressure along the axis of the pipe pile, placing the specimen in an axial compression state similar to that of actual engineering, simulating the vertical dead load transmitted from the superstructure to the pile top. The force sensor 17 is clamped in the force transmission path at the pile bottom, capable of measuring the remaining pile axial force after considering pile-soil friction, and monitoring the dynamic changes of the pile axial force in real time during the seismic response, realizing the application, maintenance, and full-process monitoring of axial force. Tensioning beam 18 is used to provide the reaction force required for prestressing tensioning, and anchorage 19 is used to lock and anchor the prestressing tendons to ensure stable and reliable axial pressure during the test.

[0031] like Figure 4 As shown, the pile cap mass block 2 is placed at the top of the prototype pipe pile specimen 4 to simulate the mass effect of the pile cap and the boundary conditions at the pile top. A connecting plate 10 is fixedly installed at the end of the pile cap mass block 2, and a flange 11 is installed at the end of the prototype pipe pile specimen 4. The connecting plate 10 and the flange 11 are arranged opposite each other and connected by bolts, welding, or a combination of bolts and welds. The connection structure can be changed according to experimental requirements to simulate pile-pile cap connection relationships with different stiffnesses and constraint conditions. A bidirectional sliding rail support 3 is installed at the bottom of the pile cap mass block 2. This support consists of a base, bidirectional guide rails, a slider, and connecting parts. The base is fixed to the vibration table surface, and the slider is connected to the pile cap mass block 2, allowing the pile cap mass block 2 to move in a controlled manner along directions parallel to and perpendicular to the pile axis. This reduces the influence of additional constraints in non-target directions and more realistically reflects the characteristics of the pile cap moving together with the pile under seismic action.

[0032] like Figure 5 , Figure 6As shown, the superstructure mass block 1 is positioned above the foundation mass block 2 to simulate the concentrated mass and inertial effects of the superstructure. The bottom of the superstructure mass block 1 is connected to the foundation mass block 2 via a one-way slide rail 12. The guide rail body of the one-way slide rail 12 is fixed to the top of the foundation mass block 2, and the slider is fixed to the bottom of the superstructure mass block 1 via a connecting plate 10 and bolts. The one-way slide rail 12 restricts the movement of the superstructure mass block 1 relative to the foundation mass block 2 only in a direction perpendicular to the pile axis, thus simulating the lateral shear deformation characteristics of the superstructure under seismic loading. A rubber bearing 13, a viscous damper 14, and an inertial capacitance device 15 are also connected in parallel between the superstructure mass block 1 and the foundation mass block 2. The upper end of the rubber bearing 13 is connected to the superstructure mass block 1, and the lower end is connected to the foundation mass block 2, providing elastic restoring force to simulate the stiffness characteristics of the superstructure. The viscous damper 14 is connected at both ends to the superstructure mass block 1 and the foundation mass block 2 via connecting seats. It outputs damping force and dissipates vibration energy during relative motion, simulating the damping energy dissipation characteristics of the superstructure. The inertial capacitance device 15 is also connected at both ends to the superstructure mass block 1 and the foundation mass block 2 via connecting seats. It outputs inertial force under relative acceleration, amplifying the equivalent inertial mass of the system. This allows for the simulation of large superstructure inertial effects without significantly increasing the weight and volume of the solid mass blocks. By adjusting the parameters of each component, superstructures with different masses, stiffness, damping, and inertial characteristics can be simulated. This method is suitable for studying the dynamic response of pile foundations in various systems, including ordinary seismic-resistant structures, vibration-damping structures, and seismic isolation structures.

[0033] The overall working principle of this invention is as follows: Before the test, the foundation constraint conditions, pile top axial compression level, pile cap connection form, and superstructure dynamic parameters are determined according to the test objectives, and all components are installed. When the shaking table inputs seismic vibration, the steel sleeve assembly 5 moves synchronously with the table surface, transmitting the seismic vibration input to the pipe pile specimen. At the same time, radial constraint and axial friction are applied to the specimen through the preloaded spring 7 and friction material 9, completing the simulation of foundation action. The prestressed loading system continuously applies axial pressure to the pipe pile, so that the specimen simultaneously bears dead load and dynamic action under seismic action, which is closer to the actual engineering stress conditions. The pile cap mass block 2 moves together with the pile under the support of the bidirectional sliding rail support 3, and the interaction between the pile and the pile cap is transmitted through the adjustable connection structure. The superstructure mass block 1 generates controlled motion relative to the pile cap mass block 2 under inertia. Through the coordinated action of the rubber support 13, viscous damper 14, and inertial capacitance device 15, the comprehensive simulation of the superstructure mass, stiffness, damping, and inertial characteristics is achieved.

[0034] During this process, the prototype pipe pile specimen 4 vibrates, deforms, and exhibits internal force responses under the combined influence of seismic motion, foundation constraints, axial pressure, pile cap action, and the inertial action of the superstructure. Force sensor 17 simultaneously collects dynamic data on the axial force changes at the pile bottom. This invention can completely reproduce the entire process of pile-soil-structure interaction under seismic loading within a limited space without requiring real soil or a real superstructure. It has advantages such as small experimental space occupation, convenient implementation, low cost, flexible adjustment of working conditions, high simulation realism, and reliable data. It can provide an efficient and reliable experimental platform for studying the seismic performance, dynamic response laws, and failure mechanisms of large-size prototype pipe piles.

[0035] Therefore, this invention employs the aforementioned prototype pipe pile shaking table test system that simulates the effects of the foundation and superstructure. The prototype pipe pile specimen is horizontally arranged on the shaking table. Steel sleeves, preloaded springs, and friction materials spaced along the pile body simulate the radial constraint of the foundation and the pile-soil friction. Prestressed tendons within the pipe pile and a force-measuring assembly at the pile bottom are used to apply axial pressure to the pile top and dynamically monitor axial force. A foundation mass block, bidirectional sliding rails, and replaceable connection structures simulate the foundation boundary. Combined with a superstructure mass block, unidirectional sliding rails, rubber bearings, viscous dampers, and inertial capacitance devices, the dynamic characteristics of the superstructure are simulated. Without requiring real soil or a real superstructure, this invention completely reproduces the stress and response process of the pile-soil-structure interaction under seismic loading within a limited test space. This effectively solves the problems of existing prototype pipe pile shaking table test systems, such as large space requirements, high cost, incomplete simulation, and difficulty in monitoring axial force.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A prototype pipe pile shaking table test system for simulating the action of foundation and superstructure, characterized in that, It includes a shaking table, a prototype pipe pile specimen horizontally arranged on the shaking table surface, a foundation action simulation component, a pile top axial compression simulation component, a pile cap simulation component, and a superstructure dynamic simulation component; the foundation action simulation component is fixed to the shaking table surface and covers the outside of the prototype pipe pile specimen, the pile top axial compression simulation component is inserted inside the prototype pipe pile specimen and extends to the outside of the pile bottom, the pile cap simulation component is connected to the top of the prototype pipe pile specimen, and the superstructure dynamic simulation component is set above the pile cap simulation component.

2. The prototype pipe pile shaking table test system for simulating the action of foundation and superstructure according to claim 1, characterized in that, The foundation action simulation component includes a steel sleeve assembly, a preload spring, a pressure plate, and friction material. The steel sleeve assembly consists of multiple steel sleeve units arranged at intervals along the axis of the prototype pipe pile specimen. The steel sleeve units are fixedly connected to the vibration table surface. One end of the preload spring is connected to the inner adjustment end plate of the steel sleeve unit, and the other end abuts against the pressure plate. The pressure plate is in contact with the friction material on the side facing the prototype pipe pile specimen.

3. The prototype pipe pile shaking table test system for simulating the action of foundation and superstructure according to claim 2, characterized in that, The steel sleeve unit is a ring-shaped sleeve structure. The adjusting end plate is installed on the side wall of the steel sleeve unit by bolts, and the preload springs are evenly distributed along the circumference of the prototype pipe pile specimen.

4. The prototype pipe pile shaking table test system for simulating the action of foundation and superstructure according to claim 2, characterized in that, The friction material is a surface contact friction plate, which is attached between the pressure plate and the outer wall of the prototype pipe pile specimen.

5. The prototype pipe pile shaking table test system for simulating the action of foundation and superstructure according to claim 1, characterized in that, The pile top axial compression simulation component includes prestressed tendons, prestressed tendon anchorage ends, force sensors, tension beams, and anchorages. The prestressed tendons are inserted through the central hole of the prototype pipe pile specimen, with one end anchored to the pile cap simulation component and the other end sequentially passing through the force sensor and tension beam, and connected to the prestressed tendon anchorage end through the anchorages. The force sensor is clamped between the pile bottom and the tension beam.

6. The prototype pipe pile shaking table test system for simulating the action of foundation and superstructure according to claim 5, characterized in that, The tensioning beam is set laterally on the outside of the pile bottom as a prestressing tendon tensioning reaction member; the anchor is sleeved at the end of the prestressing tendon that passes through the tensioning beam.

7. The prototype pipe pile shaking table test system for simulating the action of foundation and superstructure according to claim 1, characterized in that, The foundation simulation component includes a foundation mass block, a two-way slide rail support, a connecting plate, and a flange. The two-way slide rail support is fixed to the vibration table surface and supports the foundation mass block. The flange is fixed to the top of the prototype pipe pile specimen, and the connecting plate is fixed to the end of the foundation mass block. The connecting plate and the flange are connected by bolts and welds.

8. The prototype pipe pile shaking table test system for simulating the action of foundation and superstructure according to claim 7, characterized in that, The bidirectional slide rail support consists of a base, bidirectional guide rails, and a slider. The base is fixed to the vibrating table surface, and the slider is fixed to the bottom of the foundation mass block. The foundation mass block can slide in directions parallel and perpendicular to the pile axis.

9. The prototype pipe pile shaking table test system for simulating the action of foundation and superstructure according to claim 1, characterized in that, The superstructure dynamic simulation component includes a superstructure mass block, a one-way slide rail, a rubber support, a viscous damper, and an inertial capacitance device. The guide rail of the one-way slide rail is fixed to the top of the foundation mass block, and the slider is fixed to the bottom of the superstructure mass block. The rubber support, viscous damper, and inertial capacitance device are respectively connected to the foundation mass block and the superstructure mass block at both ends.

10. The prototype pipe pile shaking table test system for simulating the action of foundation and superstructure according to claim 9, characterized in that, The unidirectional slide rail restricts the upper structure mass block to move only relative to the pile cap mass block in a direction perpendicular to the pile axis; the rubber bearing, viscous damper, and inertial capacitance device are arranged in parallel.

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