A low-strain pile excitation device

Abstract

This utility model relates to the field of pile foundation testing technology, and discloses a low-strain vibration excitation device for pile foundations, including a main structure, a vibration head, a strain gauge, and a display unit. A mounting frame is provided at one end of the main structure, and a force transmission component is mounted on the mounting frame. The vibration head is connected to the mounting frame for contact with the pile to be tested. The strain gauge is located on the force transmission component and is used to detect the strain value generated by the force transmission component when the vibration head acts on the pile to be tested. The display unit is electrically connected to the strain gauge and is used to display the force value applied by the vibration excitation device to the pile to be tested. The strain value measured by the strain gauge can be used to calculate the magnitude of the reaction force on the force transmission component, and thus the excitation force applied by the vibration excitation device to the pile to be tested can be deduced. The display unit allows operators to intuitively see the excitation force applied in each vibration, facilitating the operator's understanding of the excitation force magnitude, improving the consistency and repeatability of low-strain pile foundation testing, and making the test data traceable.

Description

Technical Field

[0001] This utility model relates to the field of pile testing technology, and in particular to a low-strain vibration excitation device for piles. Background Technology

[0002] Low-strain testing technology is a commonly used method for detecting the integrity of foundation piles. It is widely used in the field of pile quality survey and has the advantages of convenient operation, high testing efficiency and no damage to the structure.

[0003] Among them, the low-strain reflected wave method (also known as the small hammer excitation method) is one of the mainstream technical methods. It uses a small hammer to apply an instantaneous excitation signal to the top of the pile to excite stress waves to propagate along the pile body. By analyzing the phase, amplitude and arrival time of the reflected waves, it is possible to determine whether there are quality problems such as defects, narrowing, widening or fracture in the pile body.

[0004] In actual testing, vibration excitation often relies on manual striking with a hammer or force bar, which introduces many uncertainties. For example, the excitation force and striking speed are highly susceptible to the operator's experience, operational state, and subjective judgment, leading to significant differences in the excitation energy and frequency components generated by different strikes or even by different operators. Inconsistent excitation signals directly affect the initial state and spectral characteristics of the stress wave, making direct comparison of test results difficult and resulting in poor repeatability. This ultimately impacts the accuracy and reliability of the final assessment of pile integrity.

[0005] Therefore, there is an urgent need for a low-strain vibration excitation device for foundation piles to solve the above problems. Utility Model Content

[0006] Based on the above problems, the purpose of this utility model is to provide a low-strain vibration excitation device for foundation piles, which can improve the consistency and repeatability of foundation pile testing, thereby improving the accuracy and reliability of foundation pile integrity assessment.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A low-strain vibration excitation device for foundation piles is provided, comprising:

[0009] The main structure has a mounting frame at one end, and a force transmission component is provided on the mounting frame, which extends along the excitation direction of the main structure.

[0010] A vibration head is connected to the mounting frame, and the vibration head is used to contact the pile to be tested.

[0011] A strain detection element is disposed on the force transmission element, and the strain detection element is used to detect the strain value generated by the force transmission element when the excitation head acts on the pile under test.

[0012] The display unit is electrically connected to the strain detection element and is used to display the force value applied by the low strain vibration device to the pile under test.

[0013] As an optional embodiment of the low-strain vibration excitation device for foundation piles of this utility model, one end of the main structure is provided with a receiving space, the mounting frame is fixed in the receiving space, and the excitation head is located outside the receiving space.

[0014] As an optional solution for the low-strain vibration excitation device for foundation piles of this utility model, the mounting frame includes a first mounting plate and a second mounting plate arranged at intervals. One end of the force transmission member is connected to the first mounting plate, and the other end is connected to the second mounting plate. The excitation head is disposed on the side of the second mounting plate facing away from the first mounting plate.

[0015] As an optional solution for the low-strain vibration excitation device for foundation piles of this utility model, four force transmission components are arranged between the first mounting plate and the second mounting plate. The four force transmission components are distributed in a square, and each force transmission component is provided with a strain detection component.

[0016] As an optional solution for the low-strain vibration excitation device for foundation piles of this utility model, a first buffer layer is provided on the side of the first mounting plate facing away from the second mounting plate.

[0017] As an optional solution for the low-strain vibration excitation device for foundation piles of this utility model, the display unit includes an electrically connected data processing module and a display screen. The strain detection element is electrically connected to the data processing module via a wire. A wire hole is provided on the first mounting plate, and the wire is led out through the wire hole.

[0018] As an optional solution for the low-strain vibration excitation device for foundation piles of this utility model, the mounting frame is provided with a heat insulation layer, which wraps around the force transmission component.

[0019] As an optional embodiment of the low-strain vibration excitation device for foundation piles of this utility model, one of the excitation head and the mounting frame is provided with a connecting column, and the other is provided with a connecting hole, wherein the connecting column is connected to the connecting hole.

[0020] As an optional solution for the low-strain vibration excitation device for foundation piles of this utility model, the excitation head has an arc-shaped excitation surface and a mounting surface. The arc-shaped excitation surface is used to contact the foundation pile to be tested, and the mounting surface faces the mounting frame. A second buffer layer is provided on the mounting surface.

[0021] As an optional solution for the low-strain vibration excitation device for foundation piles of this utility model, the strain detection element includes a strain rosette, which is disposed in the middle region of the force transmission element.

[0022] The beneficial effects of this utility model are as follows:

[0023] The low-strain vibration device for foundation piles provided by this utility model, when testing a foundation pile, uses the vibration device to strike the pile under test. During this process, the vibration head contacts the pile under test, and the entire vibration device generates an excitation force on the pile under test, completing the vibration. During the striking of the pile under test, the reaction force of the pile under test on the vibration head is transmitted to the force transmission component on the mounting frame, causing strain in the force transmission component. Therefore, the strain value measured by the strain sensor can be used to calculate the magnitude of the reaction force on the force transmission component, and thus the excitation force applied to the pile under test by the vibration device can be deduced from the force on the force transmission component (action and reaction law). Since the extension direction of the force transmission component is consistent with the excitation direction, the reaction force on the force transmission component can more accurately reflect the excitation force applied to the pile under test by the entire vibration device.

[0024] The display unit shows the excitation force applied to the pile under test by the vibration device, allowing operators to intuitively understand the magnitude of the excitation force applied in each vibration. This facilitates operators' control over the excitation force, eliminating fluctuations caused by differences in striking force, striking speed, and operator variations. It also ensures direct comparability of test results for the same pile or between different piles, standardizing the pile testing process, reducing the impact of human uncertainty on test results, and improving the consistency and repeatability of low-strain pile testing. Simultaneously, the display unit records data from each test, making the testing process traceable and supporting the completeness and reliability of the pile test report. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of the low-strain vibration excitation device for foundation piles provided in a specific embodiment of this utility model;

[0027] Figure 2 This is a structural schematic diagram of the mounting bracket and force transmission component provided in a specific embodiment of this utility model;

[0028] Figure 3 This is a top view of the mounting bracket and force transmission component provided in a specific embodiment of this utility model;

[0029] Figure 4This is a schematic diagram of the structure of the excitation head provided in a specific embodiment of this utility model.

[0030] In the picture:

[0031] 1. Main structure; 2. Mounting bracket; 3. Force transmission components; 4. Vibration excitation head; 5. Strain detection components; 6. Display unit; 7. Power supply;

[0032] 11. Accommodation space; 12. Operating handle; 13. Head;

[0033] 21. First mounting plate; 22. Second mounting plate; 23. First buffer layer; 24. Insulation layer;

[0034] 211. Threading hole; 221. Connecting hole; 222. Snap-fit ​​hole;

[0035] 41. Connecting column; 42. Arc-shaped excitation surface; 43. Mounting surface; 44. Second buffer layer; 45. Elastic snap-fit ​​component;

[0036] 51. Electrical wire;

[0037] 61. Data processing module; 62. Display screen. Detailed Implementation

[0038] To make the technical problems solved by this utility model, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0039] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Specifically, the terms "first position" and "second position" refer to two different positions.

[0040] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0041] This embodiment provides a low-strain vibration excitation device for foundation piles, which can improve the consistency and repeatability of foundation pile testing, thereby improving the accuracy and reliability of foundation pile integrity assessment.

[0042] like Figures 1 to 4 As shown, the low-strain vibration device for foundation piles includes a main structure 1, a vibration head 4, a strain detection element 5, and a display unit 6. A mounting frame 2 is installed at one end of the main structure 1, and a force transmission element 3 is mounted on the mounting frame 2, extending along the vibration direction of the main structure 1. The vibration head 4 is connected to the mounting frame 2 and is used to contact the foundation pile to be tested. The strain detection element 5 is located on the force transmission element 3 and is used to detect the strain value generated by the force transmission element 3 when the vibration head 4 acts on the foundation pile to be tested. The display unit 6 is electrically connected to the strain detection element 5 and is used to display the force value applied to the foundation pile by the low-strain vibration device.

[0043] The low-strain vibration device for foundation piles provided in this embodiment, when testing the foundation pile under test, uses the vibration device to strike the foundation pile. During this process, the vibration head 4 contacts the foundation pile under test, and the entire vibration device generates an excitation force on the foundation pile under test, completing the vibration. During the striking of the foundation pile under test, the reaction force of the foundation pile under test received by the vibration head 4 is transmitted to the force transmission component 3 on the mounting frame 2, causing strain in the force transmission component 3. Therefore, the strain value measured by the strain detection component 5 can be used to calculate the magnitude of the reaction force received by the force transmission component 3, and thus the excitation force applied by the vibration device to the foundation pile under test (action and reaction law) can be deduced from the force on the force transmission component 3. Since the extension direction of the force transmission component 3 is consistent with the excitation direction, the reaction force received by the force transmission component 3 can more accurately reflect the excitation force applied by the entire vibration device to the foundation pile under test.

[0044] The display unit 6 shows the excitation force applied to the pile under test by the vibration device, allowing operators to intuitively understand the magnitude of the excitation force applied in each vibration. This facilitates operators' control over the excitation force, eliminating fluctuations caused by differences in striking force, striking speed, and different operators. It also ensures direct comparability of test results for the same pile or between different piles, standardizing the pile testing process, reducing the impact of human uncertainty on test results, and improving the consistency and repeatability of low-strain pile testing. Simultaneously, the display unit 6 records the data from each test, making the test data traceable and supporting the completeness and reliability of the pile test report.

[0045] Furthermore, the excitation force value is displayed via display unit 6, quantifying the magnitude of the impact energy and the shape of the force pulse. The magnitude of the impact energy directly affects the propagation depth of the stress wave within the pile and the signal-to-noise ratio. The shape of the force pulse, such as its width (duration), determines the bandwidth of the stress wave's dominant frequency. Narrow pulses (short duration) excite high-frequency waves, making them sensitive to shallow defects, while wide pulses (long duration) excite low-frequency waves with slower energy decay, making them more advantageous for detecting deep defects. Therefore, the excitation force value displayed by display unit 6 allows for control of the excitation force magnitude based on the pile type and estimated defect depth, generating force pulses of the required width and energy, optimizing the excitation spectrum, and improving the ability to distinguish defects at different locations within the pile.

[0046] Optionally, the main structure 1 can be made of metallic materials, high-strength engineering plastics / composite materials, etc. For example, the main structure 1 can be made of titanium alloy or steel, giving it high rigidity and negligible deformation, thus ensuring the accuracy of the calculated force values.

[0047] See Figure 1 One end of the main structure 1 is provided with a receiving space 11, the mounting frame 2 is fixed inside the receiving space 11, and the excitation head 4 is located outside the receiving space 11. This arrangement ensures that when the pile to be tested is struck, only the excitation head 4 contacts the pile to be tested, and the reaction force received by the excitation head 4 can be effectively transmitted to the force transmission component 3 on the mounting frame 2, ensuring accurate test results.

[0048] Optionally, the mounting bracket 2 can be fixed in the accommodating cavity by means of bonding, welding, screw connection, etc., to prevent the mounting bracket 2 and the force transmission component 3 from shifting and to ensure that the force transmission component 3 can transmit force stably. In other embodiments, the mounting bracket 2 and the force transmission component 3 can also be integrally injection molded with the main structure 1, so that the mounting bracket 2 and the force transmission component 3 are embedded and fixed on the main structure 1.

[0049] Optionally, the main structure 1 includes a connected operating handle 12 and a head 13. The head 13 is provided with the aforementioned accommodating space 11, and the operating handle 12 provides operating space for the operator. In some embodiments, the operating handle 12 and the head 13 can be designed to be detachably connected (e.g., the operating handle 12 and the head 13 are threaded together), allowing the operating handle 12 and the head 13 to be machined separately, reducing machining difficulty. In some embodiments, the operating handle 12 and the head 13 can also be integrally formed.

[0050] Optionally, see Figure 1 and Figure 2 The mounting frame 2 includes a first mounting plate 21 and a second mounting plate 22 spaced apart. One end of the force transmission member 3 is connected to the first mounting plate 21, and the other end is connected to the second mounting plate 22. The excitation head 4 is located on the side of the second mounting plate 22 facing away from the first mounting plate 21. The reaction force on the excitation head 4 is transmitted to the force transmission member 3 through the second mounting plate 22, causing strain in the force transmission member 3. The first mounting plate 21 and the second mounting plate 22 provide a mounting base for the force transmission member 3, keeping it in the excitation direction of the excitation device, thereby enabling accurate measurement and calculation of the excitation force applied by the excitation device.

[0051] For example, the force transmission element 3 can be a columnar structure.

[0052] Optionally, the strain gauge 5 includes a strain rosette, which uses a Wheatstone full-bridge connection to output strain values. The strain rosette is positioned in the middle region of the force transmission component 3. The strain rosette can measure the strain at a certain point on the surface of the force transmission component 3 in different directions, thereby accurately reflecting the strain value of the force transmission component 3 at that point and improving the accuracy of the calculated force value. Since the stress-strain state in the middle region of the force transmission component 3 is uniform and stable, arranging the strain rosette in the middle region of the force transmission component 3 can more accurately obtain the axial strain of the force transmission component 3, further improving the accuracy of the force value calculation.

[0053] For example, the strain rosette can be a 45° strain rosette, which includes three resistance strain gauges whose axes are arranged at specific 45-degree angle intervals on a common substrate, for example, the axes of the three resistance strain gauges are 0°, 45° and 90° respectively.

[0054] In other embodiments, the strain detection element 5 can also be a fiber optic grating sensor, etc., which can be selected according to actual needs.

[0055] Optionally, multiple force transmission components 3 are provided, and these components 3 are symmetrically distributed in an array between the first mounting plate 21 and the second mounting plate 22. Each force transmission component 3 is equipped with a strain detection element 5. This arrangement allows the excitation force applied by the excitation device to be reflected by calculating the total resultant force on the multiple force transmission components 3, reducing measurement errors and improving the accuracy of excitation force measurement. In this embodiment, the multiple force transmission components 3 are spaced circumferentially around the center of the plane containing the first mounting plate 21 (second mounting plate 22), and are symmetrically distributed about this center. The symmetrically distributed multiple force transmission components 3 construct a statically determinate spatial force system. The eccentric force on each force transmission component 3 can be decomposed into axial force and torque. Since the torques cancel each other out in the symmetrical structure, the resultant force of the multiple force transmission components 3 is the sum of the axial forces on the multiple force transmission components 3.

[0056] Optionally, the axial force F of the force transmission component 3 is calculated using the following formula:

[0057] F = E * ε * A;

[0058] Where E is the elastic modulus of the material of the force transmission component 3, ε is the strain value measured by the strain detection component 5, and A is the cross-sectional area of ​​the force transmission component 3.

[0059] The strain value generated by the force transmission component 3 during the excitation process is detected by the strain gauge 5. Then, the stress value corresponding to the strain is calculated according to Hooke's law. Furthermore, the axial force F of the force transmission component 3 is obtained by multiplying the stress by the cross-sectional area. Among them, the elastic modulus of the force transmission component 3 is determined according to its material and is a known value; ε is the detected value and is a known value; the cross-sectional area A of the force transmission component 3 is determined according to its size and is also a known value.

[0060] Specifically, in this embodiment Figure 2 and Figure 3 In this structure, four force transmission components 3 are arranged between the first mounting plate 21 and the second mounting plate 22, and the four force transmission components 3 are distributed in a square. The four force transmission components 3 distributed in a square essentially construct a statically determinate spatial force system. The eccentric force on each force transmission component 3 can be decomposed into axial force and torque. Since the torques cancel each other out in a symmetrical structure, the resultant force of the four force transmission components 3 is the sum of the axial forces on the four force transmission components 3. This resultant force is equal in magnitude and opposite in direction to the excitation force applied by the excitation device to the pile under test.

[0061] Taking four force transmission components 3 arranged in a square as an example, it is shown below that the sum of the axial forces on the four force transmission components 3 is the resultant force of the four force transmission components 3.

[0062] When an eccentric force is present, a bending moment will be generated, and the total strain generated by a single force transmission component 3 is:

[0063]

[0064] Where, ε F The strain is generated by the axial force F of the force transmission component 3:

[0065]

[0066] Bending moment M x It is the bending moment component generated by the eccentricity y about the X-axis:

[0067]

[0068] Bending moment M y It is the bending moment component generated by the eccentricity x about the y-axis:

[0069]

[0070] I is the moment of inertia of the combined cross section of the force transmission component 3.

[0071] Assume the origin of the coordinate system is located at the center of the four force transmission components 3, with coordinates (x, y), and the distance between any two adjacent force transmission components 3 is d. The moment of inertia is I = Ad. 2 .

[0072] Therefore, the coordinates of the first force transmission component 3 are (x1, y1) = (d / 2, d / 2);

[0073] The coordinates of the second force transmission component 3 are (x2, y2) = (d / 2, d / 2);

[0074] The coordinates of the third force transmission component 3 are (x3, y3) = (-d / 2, -d / 2);

[0075] The coordinates of the fourth force transmission component 3 are (x4, y4) = (d / 2, -d / 2).

[0076] The force acting on the first force transmission component 3:

[0077]

[0078] The force acting on the second force transmission component 3:

[0079]

[0080] The force acting on the third force transmission component 3:

[0081]

[0082] The force acting on the fourth force transmission component 3 is:

[0083]

[0084] The resultant force of the four force transmission components 3 is:

[0085] F total =F1 total +F2 total +F3 total +F4 total ;

[0086] therefore:

[0087]

[0088] and:

[0089]

[0090] Therefore:

[0091]

[0092] That is, the resultant force of the four force transmission components 3 is the sum of the axial forces of the four force transmission components 3, and F1, F2, F3, and F4 are the axial forces of the four force transmission components 3 respectively.

[0093] In other embodiments, the force transmission element 3 can also be designed in other quantities, such as 6 or 8 force transmission elements 3, as long as the resultant force of multiple force transmission elements 3 can be guaranteed to be the sum of the axial forces on multiple force transmission elements 3, and is not limited to the quantities and distribution methods listed above.

[0094] Optionally, see Figure 1 and Figure 2 A first buffer layer 23 is provided on the side of the first mounting plate 21 facing away from the second mounting plate 22. The first buffer layer 23 can absorb the vibration generated during the excitation process of the excitation device, prevent or reduce the deformation of the mounting frame 2 and the main structure 1, ensure the accuracy of the test results, and extend the service life of the excitation device.

[0095] For example, the first buffer layer 23 can be a honeycomb structure (such as a hexagonal honeycomb structure), which can effectively absorb the vibration generated during the excitation process. In other embodiments, the first buffer layer 23 can also be a rubber pad or the like, as long as it can meet the buffering requirements.

[0096] Optionally, see Figure 1 and Figure 2The display unit 6 includes a data processing module 61 and a display screen 62 that are electrically connected. The strain detection element 5 is electrically connected to the data processing module 61 via a wire 51. A wire hole 211 is provided on the first mounting plate 21, through which the wire 51 is led out. That is, the wire 51 on the strain detection element 5 is led out through the wire hole 211 and connected to the data processing module 61. The data processing module 61 is used to process the strain data measured by the strain detection element 5 to calculate the excitation force applied by the excitation device. The display screen 62 then displays the excitation force value calculated by the data processing module 61, so that the operator can view the magnitude of the excitation force.

[0097] In this embodiment, a wire hole 211 is provided on the first mounting plate 21 for each strain gauge 5. The wire 51 of each strain gauge 5 is led out from the corresponding wire hole 211 and connected to the data processing module 61, so that the data processing module 61 can receive the detection value of each strain gauge 5. In other embodiments, a single wire hole 211 can be provided on the first mounting plate 21, and multiple wires 51 can be gathered and led out through this single wire hole 211. The number and distribution of wire holes 211 can be selected according to actual needs during the design process.

[0098] Optionally, see Figure 1 , Figure 2 and Figure 3 The mounting frame 2 is equipped with a thermal insulation layer 24, which surrounds the force transmission component 3. By setting a thermal insulation layer 24 around the force transmission component 3, the influence of temperature on the strain gauge 5 can be greatly reduced, preventing excessive temperature changes from affecting the detection accuracy of the strain gauge 5. At the same time, the thermal insulation layer 24 can isolate the strain gauge 5 from the outside, preventing foreign objects from adhering to the strain gauge 5 and affecting the detection results, thus ensuring the accuracy of the detection results of the strain gauge 5.

[0099] In this embodiment, multiple force transmission components 3 are provided, and the heat insulation layer 24 surrounds the multiple force transmission components 3 and is located between the first mounting plate 21 and the second mounting plate 22, so that the strain detection components 5 on the multiple force transmission components 3 can be heat-insulated and isolated from the external space.

[0100] For example, the insulation layer 24 can be made of hard rubber, which has good insulation effect. In other embodiments, the insulation layer 24 can also be made of polyurethane foam, etc., depending on the actual needs. The material of the insulation layer 24 is not limited here.

[0101] Optionally, see Figure 1 The low-strain vibration device for the foundation pile also includes a power supply 7, which is electrically connected to the display unit 6 to supply power to the display unit 6, enabling the data processing module 61 of the display unit 6 to work normally, process the data measured by the strain detection element 5, and enable the display screen 62 to stably display the corresponding data.

[0102] For example, the power source 7 can be a dry cell battery, with a battery compartment provided on the main structure 1 to house the dry cell battery. Alternatively, the power source 7 can also be a rechargeable battery.

[0103] Optionally, see Figure 1 , Figure 2 and Figure 4 One of the exciter head 4 and the mounting bracket 2 is provided with a connecting post 41, and the other is provided with a connecting hole 221. The connecting post 41 is connected to the connecting hole 221. The cooperation between the connecting post 41 and the connecting hole 221 enables the exciter head 4 and the mounting bracket 2 to be detachably assembled, thereby facilitating the replacement of the exciter head 4.

[0104] For example, the connecting post 41 can be a threaded post, and the connecting hole 221 can be a threaded hole. The exciter head 4 can be installed and removed by screwing in the thread, which is simple and convenient.

[0105] In this embodiment, the excitation head 4 is made of various materials, each corresponding to different hardness and hammering force. For example, various excitation heads 4 made of materials such as nylon, steel, aluminum, plastic, and rubber can be used. When performing low-strain testing on foundation piles, the appropriate excitation head 4 is selected and installed on the mounting frame 2 according to the pile type, estimated defect depth, and other testing requirements. By changing to an excitation head 4 made of a suitable material, force pulses of the required width and energy can be generated, greatly improving the consistency and repeatability of foundation pile testing.

[0106] Optionally, see Figure 2 and Figure 4 The connecting column 41 is provided with an elastic snap-fit ​​member 45, and the second mounting plate 22 of the mounting bracket 2 is provided with a snap-fit ​​hole 222 communicating with the connecting hole 221. The snap-fit ​​hole 222 is located outside the connecting hole 221. When the connecting column 41 is connected to the connecting hole 221, the elastic snap-fit ​​member 45 can be snapped into the snap-fit ​​hole 222, which can prevent the connecting column 41 from loosening and ensure that the vibration head 4 and the mounting bracket 2 are reliably connected during the use of the vibration device.

[0107] For example, the elastic snap-fit ​​45 can be a rubber pad, or it can be a nylon pad, etc., as long as it can prevent the connecting post 41 from loosening.

[0108] Optionally, see Figure 4The excitation head 4 has an arc-shaped excitation surface 42 and a mounting surface 43. The arc-shaped excitation surface 42 is used to contact the pile under test, and the mounting surface 43 faces the mounting frame 2. A second buffer layer 44 is provided on the mounting surface 43. The arc-shaped excitation surface 42 allows the excitation head 4 to contact the pile under test in an approximately point-source manner, achieving approximately point source excitation, which facilitates subsequent theoretical analysis. In addition, the arc-shaped excitation surface 42 can concentrate the impact energy in a small area, avoiding or reducing the risk of breaking the pile under test or causing local cracking.

[0109] By setting a second buffer layer 44, the vibration generated during the excitation process of the excitation device can be absorbed, the strength and deformation capacity of the excitation head 4 can be enhanced, stress concentration can be prevented, damage to the excitation head 4 can be avoided, and the service life of the excitation head 4 can be extended.

[0110] For example, the second buffer layer 44 can be a honeycomb structure (such as a hexagonal honeycomb structure), which can effectively absorb the vibration generated during the excitation process. In other embodiments, the second buffer layer 44 can also be a rubber pad or the like, as long as it can meet the buffering requirements.

[0111] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A low-strain vibration excitation device for foundation piles, characterized in that, include: The main structure (1) has a mounting frame (2) at one end, and a force transmission component (3) is provided on the mounting frame (2), which extends along the excitation direction of the main structure (1). The excitation head (4) is connected to the mounting frame (2) and is used to contact the pile to be tested; A strain detection element (5) is disposed on the force transmission element (3). The strain detection element (5) is used to detect the strain value generated by the force transmission element (3) when the excitation head (4) acts on the pile to be tested. The display unit (6) is electrically connected to the strain detection element (5). The display unit (6) is used to display the force value applied by the low strain vibration device of the foundation pile to the foundation pile under test.

2. The low-strain vibration excitation device for foundation piles according to claim 1, characterized in that, One end of the main structure (1) is provided with a accommodating space (11), the mounting bracket (2) is fixed in the accommodating space (11), and the excitation head (4) is located outside the accommodating space (11).

3. The low-strain vibration excitation device for foundation piles according to claim 1, characterized in that, The mounting bracket (2) includes a first mounting plate (21) and a second mounting plate (22) spaced apart. One end of the force transmission member (3) is connected to the first mounting plate (21), and the other end is connected to the second mounting plate (22). The excitation head (4) is located on the side of the second mounting plate (22) facing away from the first mounting plate (21).

4. The low-strain vibration excitation device for foundation piles according to claim 3, characterized in that, Four force transmission components (3) are provided between the first mounting plate (21) and the second mounting plate (22). The four force transmission components (3) are arranged in a square. Each force transmission component (3) is provided with a strain detection component (5).

5. The low-strain vibration excitation device for foundation piles according to claim 3, characterized in that, A first buffer layer (23) is provided on the side of the first mounting plate (21) facing away from the second mounting plate (22).

6. The low-strain vibration excitation device for foundation piles according to claim 3, characterized in that, The display unit (6) includes a data processing module (61) and a display screen (62) that are electrically connected. The strain detection element (5) is electrically connected to the data processing module (61) via a wire (51). The first mounting plate (21) is provided with a wire hole (211), and the wire (51) is led out through the wire hole (211).

7. The low-strain vibration excitation device for foundation piles according to any one of claims 1-6, characterized in that, The mounting bracket (2) is provided with a heat insulation layer (24), which is wrapped around the force transmission component (3).

8. The low-strain vibration excitation device for foundation piles according to any one of claims 1-6, characterized in that, One of the excitation head (4) and the mounting bracket (2) is provided with a connecting post (41), and the other is provided with a connecting hole (221). The connecting post (41) is connected to the connecting hole (221).

9. The low-strain vibration excitation device for foundation piles according to any one of claims 1-6, characterized in that, The excitation head (4) has an arc-shaped excitation surface (42) and a mounting surface (43). The arc-shaped excitation surface (42) is used to contact the pile to be tested. The mounting surface (43) faces the mounting frame (2). A second buffer layer (44) is provided on the mounting surface (43).

10. The low-strain vibration excitation device for foundation piles according to any one of claims 1-6, characterized in that, The strain detection element (5) includes a strain rosette, which is disposed in the middle region of the force transmission element (3).

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