A pile foundation shaking table test device

Abstract

This utility model relates to the field of civil engineering technology, specifically a pile foundation shaking table test device. It includes a shaking table body, a container on top of which holds soil and a pile foundation model. The container includes a coaxially arranged rigid inner frame and a rigid outer frame. A flexible sidewall structure is provided between the rigid inner frame and the rigid outer frame. The flexible sidewall structure consists of circumferentially spliced ​​flexible plates and multiple sets of micro-springs connecting the inner surface of the flexible plates to the outer surface of the rigid inner frame. The top and bottom of the flexible plates are connected to the rigid inner and outer frames via sliding guide components to allow radial displacement of the flexible plates in the horizontal plane. This pile foundation shaking table test device, by improving the boundary structure, effectively reduces the soil boundary effect, more realistically simulates the interaction between the pile and soil system under seismic loading, and improves the accuracy of the test.

Description

Technical Field

[0001] This utility model relates to the field of civil engineering technology, specifically to a pile foundation shaking table test device. Background Technology

[0002] As an important foundation type, pile foundations are widely used in various building projects, and their stability under seismic loading directly affects the safety of the overall structure. In order to study the dynamic response and failure mechanism of pile foundations under seismic loading, it is often necessary to conduct model tests in the laboratory using a shaking table to evaluate their seismic performance by simulating seismic motion.

[0003] When conducting model tests, existing pile foundation shaking table test devices typically fix the pile foundation model directly to the shaking table surface or place it in a rigid container filled with soil. This rigid boundary condition significantly affects the free deformation of the soil, producing obvious boundary effects during earthquake simulation. This leads to distortion of the stress and strain field distribution inside the soil, failing to accurately reflect the actual working state of the pile-soil interaction, thus reducing the accuracy and reliability of the test results. Utility Model Content

[0004] The purpose of this invention is to provide a pile foundation shaking table test device to solve the problem mentioned in the background art that the current pile foundation shaking table test devices use rigid boundary containers, resulting in significant soil boundary effects and failing to truly simulate the dynamic interaction between the pile and soil in the free field, thus affecting the accuracy of the test results.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a pile foundation shaking table test device, comprising a shaking table body, a container body on the top of the shaking table body, soil being placed inside the container body and a pile foundation model being provided, the container body comprising a rigid inner frame and a rigid outer frame coaxially arranged, a flexible sidewall structure being provided between the rigid inner frame and the rigid outer frame, the flexible sidewall structure being composed of circumferentially spliced ​​flexible plates and multiple sets of micro springs connecting the inner side of the flexible plates and the outer side of the rigid inner frame, the top and bottom of the flexible plates being connected to the rigid inner frame and the rigid outer frame through sliding guide components to allow the flexible plates to undergo radial displacement in the horizontal plane.

[0006] Preferably, the bottoms of both the rigid inner frame and the rigid outer frame are directly fixed to the table surface of the vibration table body by bolts. The two are arranged concentrically on the vibration table body, and the space enclosed by the rigid inner frame is used to hold the soil and pile foundation model.

[0007] Preferably, the flexible plate is made of a highly elastic rubber material, and parallel reinforcing ribs are embedded inside it along the height direction, with the two ends of the reinforcing ribs being welded and fixed to the outer wall of the flexible plate.

[0008] Preferably, an annular groove is provided on the top outer wall of the rigid inner frame, and an annular slider matching the annular groove is provided on the top inner side of the flexible plate. The annular slider is embedded in the annular groove and can slide along its circumference.

[0009] Preferably, the flexible plate is provided with T-shaped sliders at the top and bottom, and the inner wall of the rigid outer frame and the outer wall of the rigid inner frame are provided with vertical limiting guide grooves.

[0010] Preferably, the micro springs are helical compression springs and are evenly distributed at intervals of 100-150mm along the height direction of the flexible plate. 3-6 sets of micro springs are connected between the inner side of the flexible plate and the outer side of the rigid inner frame, and one end of the micro spring is fixed to the inner side of the flexible plate and the other end is fixed to the outer side of the rigid inner frame.

[0011] Compared with existing technologies, the beneficial effects of this invention are as follows: This pile foundation shaking table test device effectively reduces soil boundary effects by improving the boundary structure, more realistically simulating the interaction between the pile and soil system under seismic loading, and improving the accuracy of the test. This device, through the use of a flexible sidewall structure composed of flexible plates, micro-springs, and sliding guide components, combined with the synergistic effect of a rigid inner frame and a rigid outer frame, achieves reasonable constraint and elastic response to lateral soil deformation, avoiding stress concentration and deformation obstruction problems caused by rigid boundaries. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of a pile foundation vibration table test device according to the present invention;

[0013] Figure 2 This is a top view of the structure of a pile foundation shaking table test device according to the present invention;

[0014] Figure 3 This is a schematic diagram of the flexible plate outer wall structure of a pile foundation vibration table test device according to this utility model.

[0015] In the figure: 1. Shaking table body; 2. Container body; 3. Pile foundation model; 4. Rigid inner frame; 41. Annular groove; 5. Rigid outer frame; 6. Flexible plate; 61. Reinforcing rib; 62. Annular slider; 63. T-shaped slider; 7. Miniature spring. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figure 1-3This utility model provides a technical solution: a pile foundation shaking table test device, including a shaking table body 1, a container body 2 on the top of the shaking table body 1, soil inside the container body 2 and a pile foundation model 3, the pile foundation model 3 being a scaled-down test model used to simulate the pile foundation structure in actual engineering, the container body 2 including a rigid inner frame 4 and a rigid outer frame 5 coaxially arranged, both the rigid inner frame 4 and the rigid outer frame 5 being rectangular steel structure frames with a "U" shaped cross-section, the side wall height of the rigid inner frame 4 being lower than the side wall height of the rigid outer frame 5, a flexible side wall structure between the rigid inner frame 4 and the rigid outer frame 5, the flexible side wall structure consisting of circumferentially spliced ​​flexible plates 6 and multiple sets of micro elastics connected between the inner side of the flexible plates 6 and the outer side of the rigid inner frame 4. The structure consists of four flexible plates 6, each a rectangular plate. The top and bottom of each flexible plate 6 are connected to the rigid inner frame 4 and rigid outer frame 5 via sliding guide components, allowing the flexible plate 6 to undergo radial displacement in the horizontal plane. When an earthquake occurs on the shaking table body 1, causing the container body 2 on it to vibrate as a whole, the soil within the rigid inner frame 4 generates inertial force, pushing its sidewalls to deform laterally. This deformation force is first transmitted to the flexible plate 6, which is in direct contact with the soil. After being subjected to force, the flexible plate 6 begins to undergo radial displacement along the horizontal plane. At this time, multiple sets of micro-springs 7 between the inner surface of the flexible plate 6 and the outer surface of the rigid inner frame 4 are compressed or stretched, providing a restoring force adapted to the lateral pressure of the soil, simulating the lateral reaction characteristics of the soil. Simultaneously, the flexible plate 6... The top and bottom, through the synergistic action of sliding guide components with the rigid inner frame 4 and rigid outer frame 5, ensure that the flexible plate 6 maintains a stable trajectory during radial displacement. This allows for necessary sliding deformation relative to the rigid inner frame 4 while preventing instability through the constraint of the rigid outer frame 5. The entire flexible sidewall structure absorbs and regulates the lateral displacement of the soil through the deformation of the flexible plate 6, while the micro-spring 7 provides elastic constraints. The sliding guide components ensure smooth and controllable movement, effectively weakening the rigid boundary constraints on the free deformation of the soil imposed by traditional rigid containers. This significantly reduces boundary effects, making the stress and strain field distribution inside the soil closer to the free field state in real strata, and more realistically reflecting the pile foundation model 3 and its surroundings under seismic loading. The dynamic interaction mechanism between the surrounding soil and the concrete solves the problems in existing technologies where the use of rigid boundary containers leads to significant soil boundary effects, distorted stress and strain distribution, and an inability to accurately simulate the actual working conditions of piles and soil, thus affecting the reliability of test results. The bottoms of both the rigid inner frame 4 and the rigid outer frame 5 are directly bolted to the platform of the shaking table body 1. They are concentrically arranged on the shaking table body 1, and the space enclosed by the rigid inner frame 4 is used to hold the soil and pile foundation model 3. This structure ensures that the rigid inner frame 4 and the rigid outer frame 5 maintain precise concentric positioning and stable connection relative to the shaking table body 1 during vibration, providing a stable mechanical foundation for the normal operation of the flexible sidewall structure and avoiding boundary condition distortion caused by frame loosening or displacement.To ensure the accuracy of soil deformation response measurements during the experiment, the flexible plate 6 is made of highly elastic rubber material. Parallel reinforcing ribs 61 are embedded within its interior along its height direction, with both ends of the ribs 61 welded and fixed to the outer wall of the flexible plate 6. This structure allows the flexible plate 6 to withstand repeated cyclic lateral pressure from the soil during earthquake simulations. Its material endows it with excellent deformation capacity and recovery characteristics, effectively adapting to the reciprocating motion of the soil. The reinforcing ribs 61 significantly improve the overall structural strength and tensile properties of the flexible plate 6, preventing tearing or excessive stretching under large deformations. Simultaneously, the reinforcing ribs 61 ensure that stress is evenly transmitted to the upper and lower boundaries of the flexible plate 6, maintaining its shape stability during radial deformation and avoiding local buckling or wrinkling. This ensures the durability and reliable mechanical response of the flexible plate 6 under long-term cyclic operation. An annular groove 41 is provided on the top outer wall of the rigid inner frame 4, and an annular slider 62, matching the annular groove 41, is provided on the top inner side of the flexible plate 6. The annular slider 62 is embedded in the annular groove 41 and can slide freely along its circumference. When the shaking table body 1 vibrates during a simulated earthquake, the soil within the rigid inner frame 4 applies lateral pressure to the flexible plate 6, causing radial displacement of the flexible plate 6. The annular slider 62 is embedded in the annular groove 41 and can slide freely along its circumference. This allows the flexible plate 6 to flexibly adjust its position in the horizontal plane to adapt to the deformation requirements of the soil. This not only ensures that the flexible plate 6 can smoothly operate under lateral forces... The flexible plate 6 moves freely without obstruction, ensuring a tight connection and coordinated movement between the flexible plate 6 and the rigid inner frame 4. This prevents stress concentration or structural damage that may be caused by poor relative sliding, thus maintaining the stability and reliability of the entire test device. T-shaped sliders 63 are provided at both the top and bottom of the flexible plate 6, and vertical limiting guide grooves are provided on the inner wall of the rigid outer frame 5 and the outer wall of the rigid inner frame 4. When the flexible plate 6 undergoes radial displacement under the lateral pressure of the soil, the T-shaped sliders 63 at its top and bottom slide synchronously within the vertical limiting guide grooves on the inner wall of the rigid outer frame 5 and the outer wall of the rigid inner frame 4, respectively. This together forms a stable and reliable double-layer sliding guide system, effectively constraining the vertical movement of the flexible plate 6. The flexible sidewall structure features rotational degrees of freedom, preventing potential jumping, tilting, or instability under complex dynamic loads. This ensures the stability and coordination of the flexible sidewall structure's motion during long-term cyclic vibration. The micro-springs 7 are helical compression springs, evenly distributed at 100-150mm intervals along the height of the flexible plate 6. Three to six sets of micro-springs 7 connect the inner surface of the flexible plate 6 to the outer surface of the rigid inner frame 4. One end of each micro-spring 7 is fixed to the inner side of the flexible plate 6, and the other end is fixed to the outer surface of the rigid inner frame 4. This structure allows the micro-springs 7 to provide corresponding reaction forces, enabling the flexible plate 6 to adapt to soil deformation while appropriately constraining and buffering its displacement. This ensures that the stress transfer at the soil boundary is closer to the free field conditions under natural conditions.This design avoids the problems of reflected waves and stress concentration caused by rigid boundaries, effectively reducing the impact of boundary effects on test results and improving the realism and accuracy of simulating the interaction between the pile foundation and the surrounding soil. Furthermore, the uniformly distributed micro-springs ensure the stress balance of the entire flexible sidewall structure at different heights, enhancing the overall stability and durability of the system.

[0018] Working principle: When using this pile foundation shaking table test device, the shaking table body 1 is first started and begins to vibrate according to the preset seismic wave acceleration time history curve. The shaking table body 1 transmits power to the rigid inner frame 4 and rigid outer frame 5 fixed on it. The soil inside the rigid inner frame 4 generates reciprocating motion under the action of inertia, applying periodic lateral pressure to the flexible plate 6 in contact with it. Under the action of lateral pressure, the flexible plate 6 slides in the annular groove 41 of the rigid inner frame 4 through the annular slider 62 at its top, and slides in the vertical limiting guide groove of the rigid outer frame 5 and the rigid inner frame 4 through the T-shaped sliders 63 at its top and bottom, realizing horizontal radial reciprocating displacement. At the same time, multiple sets of micro springs 7 connected between the inner side of the flexible plate 6 and the outer side of the rigid inner frame 4 are alternately compressed and stretched with the movement of the flexible plate 6, continuously performing deformation response. During the vibration process, the pile foundation model 3 interacts with the surrounding soil, and its dynamic response is collected in real time by sensors arranged in the pile body and soil, thereby completing a series of tasks.

[0019] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pile foundation shaking table test apparatus, comprising a shaking table body (1), wherein a container (2) is provided on the top of the shaking table body (1), the container (2) contains soil and a pile foundation model (3), characterized in that: The container body (2) includes a rigid inner frame (4) and a rigid outer frame (5) arranged coaxially. A flexible sidewall structure is provided between the rigid inner frame (4) and the rigid outer frame (5). The flexible sidewall structure is composed of a circumferentially spliced ​​flexible plate (6) and multiple sets of micro springs (7) connected between the inner side of the flexible plate (6) and the outer side of the rigid inner frame (4). The top and bottom of the flexible plate (6) are connected to the rigid inner frame (4) and the rigid outer frame (5) through sliding guide components to allow the flexible plate (6) to undergo radial displacement in the horizontal plane.

2. The pile foundation shaking table test device according to claim 1, characterized in that: The bottom of the rigid inner frame (4) and the rigid outer frame (5) are directly fixed to the table surface of the vibration table body (1) by bolts. The two are arranged concentrically on the vibration table body (1), and the space enclosed by the rigid inner frame (4) is used to hold the soil and pile foundation model (3).

3. The pile foundation shaking table test device according to claim 1, characterized in that: The flexible plate (6) is made of high elastic rubber material, and parallel reinforcing ribs (61) are embedded in its interior along the height direction. The two ends of the reinforcing ribs (61) are welded and fixed to the outer wall of the flexible plate (6).

4. The pile foundation shaking table test device according to claim 1, characterized in that: The rigid inner frame (4) has an annular groove (41) on its top outer side wall, and the flexible plate (6) has an annular slider (62) that matches the annular groove (41) on its top inner side. The annular slider (62) is embedded in the annular groove (41) and can slide along its circumference.

5. The pile foundation shaking table test device according to claim 1, characterized in that: The flexible plate (6) is provided with T-shaped sliders (63) at the top and bottom, and the rigid outer frame (5) and the rigid inner frame (4) are provided with vertical limiting guide grooves.

6. The pile foundation shaking table test device according to claim 1, characterized in that: The micro springs (7) are helical compression springs and are evenly distributed at intervals of 100-150mm along the height direction of the flexible plate (6). There are 8-12 sets of micro springs (7) connected between the inner side of the flexible plate (6) and the outer side of the rigid inner frame (4). One end of the micro springs (7) is fixed to the inner side of the flexible plate (6) and the other end is fixed to the outer side of the rigid inner frame (4).

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