Device and method for detecting impact feedback frequency of pile hammer in karst cave area

Abstract

The invention discloses a pile hammer impact feedback frequency detection device and method for a karst cave area, and relates to the technical field of pile foundation construction detection.The pile hammer impact feedback frequency detection device comprises a pile hammer body, a fixing mechanism is arranged on the outer wall of the pile hammer body, a reinforcing mechanism is arranged on the outer wall of the pile hammer body, and a protection box is arranged on the outer wall of the fixing mechanism; a pressure sensor is fixedly installed in a reserved groove in the bottom of the pile hammer body, an acceleration sensor is arranged in the protection box, and a sealing plate is arranged at the upper end of the protection box. The fixing mechanism comprises a first semicircular plate and a second semicircular plate. According to the pile hammer, the acceleration sensor can be fixed in the protection box, the acceleration sensor is prevented from falling off from the pile hammer body due to strong impact and continuous vibration, detection data are prevented from being lost or inaccurate, safety is improved, and the construction cost and the construction period delay risk cannot be increased.

Description

Technical Field

[0001] The present invention relates to the technical field of pile foundation construction detection, and in particular to a device and method for detecting the impact feedback frequency of a pile hammer in a karst cave area. Background Art

[0002] With the rapid development of transportation infrastructure construction, especially in areas with complex geological conditions, cave detection and pile foundation construction have become crucial for ensuring project quality and safety. However, when constructing pile foundations in cave areas, a detection device is required to obtain the feedback frequency of the pile hammer's impact to ensure construction quality. Accelerometers, as key components of detection devices, play an important role in monitoring the dynamics of the pile hammer's impact.

[0003] In the existing technology, the strong impact and continuous vibration generated by the pile hammer during operation affect the installation stability of the acceleration sensor, which can easily cause the installation components to loosen and the acceleration sensor to fall off, and even cause the detection data to be lost or inaccurate, seriously affecting the judgment of the pile hammer's impact state, posing a safety hazard to pile foundation construction, and increasing construction costs and the risk of project delays. This paper proposes a pile hammer impact feedback frequency detection device and method for use in karst cave areas. Summary of the Invention

[0004] The object of the present invention is to provide a device and method for detecting the impact feedback frequency of a pile hammer in a karst cave area, so as to solve the problems raised by the above-mentioned background technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a device for detecting the impact feedback frequency of a pile hammer in a karst cave area, comprising a pile hammer body, a fixing mechanism provided on the outer wall of the pile hammer body, a reinforcement mechanism provided on the outer wall of the pile hammer body, a protection box provided on the outer wall of the fixing mechanism, a pressure sensor fixedly mounted in a reserved groove at the bottom of the pile hammer body, an acceleration sensor provided within the protection box, and a sealing plate provided at the upper end of the protection box;

[0006] The fixing mechanism includes a No. 1 semicircular plate and a No. 2 semicircular plate, the outer walls of the No. 1 semicircular plate and the No. 2 semicircular plate are fixedly installed with anti-slip latex pads, one end of the No. 2 semicircular plate is welded with four groups of short screws, one end of the No. 1 semicircular plate is penetrated by four groups of round holes, one end of the No. 1 semicircular plate is provided with two groups of square grooves, the upper end of the No. 1 semicircular plate is provided with a vertical groove, one end of the four groups of round holes is provided with two groups of hexagonal nuts, both sides of the sealing plate are welded with semicircular connecting plates, and the outer walls of the two groups of the semicircular connecting plates are welded with square hole plates;

[0007] It also includes a height data acquisition module, a data processing and analysis module, a data processing and analysis module, a data storage and display module and a power management module. The pressure sensor and the acceleration sensor are both signal-connected to the high-speed data acquisition module, the high-speed data acquisition module is signal-connected to the data processing and analysis module, the data processing and analysis module is signal-connected to the data processing and analysis module, and the pressure sensor, the acceleration sensor, the height data acquisition module, the data processing and analysis module, the data processing and analysis module and the data storage and display module are all electrically connected to the power management module.

[0008] Preferably, a latex frame is installed inside the protective box, and the inner wall of the latex frame is in contact with the outer wall of the acceleration sensor, and a latex plate is fixedly installed on the lower end of the sealing plate.

[0009] Preferably, the reinforcement mechanism includes a circular ring seat, the upper and lower ends of the No. 1 semicircular plate and the No. 2 semicircular plate are welded with semicircular blocks, the upper end of the circular ring seat is welded with a circular ring plate, and the lower end of the circular ring plate is welded with multiple groups of long screws, and the upper and lower ends of the No. 1 semicircular plate are respectively provided with a No. 1 limiting ring and a No. 2 limiting ring, the outer wall of the No. 1 limiting ring is welded with multiple groups of No. 1 seats, and the outer wall of the No. 2 limiting ring is welded with multiple groups of No. 2 seats, and the outer walls of the multiple groups of the long screws are threadedly connected with No. 1 nuts and No. 2 nuts in sequence from top to bottom.

[0010] Preferably, the two ends of the semicircular connecting plate are respectively inserted into the interior of the two groups of vertical grooves, the two groups of square hole plates are respectively arranged inside the two groups of square grooves, each of the short screws is respectively inserted into the interior of the corresponding circular hole, and one end of the two groups of short screws is respectively inserted into the interior of the two groups of square hole plates.

[0011] Preferably, the eight groups of hexagonal nuts are respectively fixed to the outer walls of the four groups of short screws, the No. 1 semicircular plate and the No. 2 semicircular plate are in contact with the outer wall of the pile hammer body through anti-slip latex pads, and the protective box is welded to the outer wall of the No. 1 semicircular plate.

[0012] Preferably, the outer walls of each two groups of semicircular blocks are in contact with the inner walls of the No. 1 limiting ring and the No. 2 limiting ring, and one end of each group of long screws is inserted into the interior of the No. 1 seat and the No. 2 seat in sequence.

[0013] Preferably, the annular seat is sleeved on the outer wall of the pile hammer body, and the lower end of the annular plate is in contact with the upper end of the pile hammer body.

[0014] Preferably, the lower end of the latex plate contacts the upper end of the acceleration sensor, and the lower end of the sealing plate is penetrated by four groups of limiting holes.

[0015] Preferably, limiting posts are inserted into the interiors of the four groups of limiting holes, and the lower ends of the four groups of limiting posts are fixed to the upper end of the protective box.

[0016] A method for detecting a pile hammer impact feedback frequency in a karst cave area comprises the following steps:

[0017] S1. Device Installation and Initialization: Install the acceleration sensor inside the protective box according to the design requirements, and install the pressure sensor in the reserved groove at the bottom of the pile hammer body according to the design requirements, and ensure that the connection is firm. Initialize the high-speed data acquisition module, data processing and analysis module, and data storage and display module, including sampling frequency, filter parameters, storage path, etc.

[0018] S2. Data acquisition: When the hammer body is performing an impact operation, the high-speed data acquisition module synchronously collects the signals output by the acceleration sensor and the pressure sensor, converts them into digital signals through the data processing and analysis module, and stores them in the data storage and display module. The acquisition process should last for a period of time to obtain sufficient impact data samples;

[0019] S3. Data preprocessing: Preprocess the collected raw data, including noise removal and baseline correction. Digital filtering algorithms, such as Butterworth filters, can be used to remove high-frequency noise and low-frequency interference in the signal.

[0020] S4. Feature extraction: Use spectrum analysis methods, such as fast Fourier transform, to analyze the pre-processed data to obtain the signal spectrum. The impact feedback frequency of the pile hammer body can be extracted from the spectrum by finding the peak frequency in the spectrum.

[0021] S5. Result Analysis and Evaluation: Based on the extracted impact feedback frequency, combined with factors such as the geological conditions of the karst cave area and the pile design parameters, the impact effect of the pile hammer and the bearing capacity of the pile foundation are analyzed. For example, if the impact feedback frequency shows abnormal changes, it means that the pile bottom has encountered a karst cave or other geological defects, requiring further investigation and analysis.

[0022] S6. Data storage and report generation: The processed data and analysis results are stored in the storage module, and a detailed test report is generated. The report should include information such as the test time, location, pile number, impact feedback frequency, as well as analysis and suggestions on the test results.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. In the present invention, a fixing mechanism is provided. With the cooperation of the first and second semicircular plates, the short screw, and the hexagonal nut, and further with the cooperation of the two sets of semicircular connecting plates and the two sets of square hole plates, the two sets of vertical slots, and the two sets of square slots, the two sets of square hole plates can be fixed inside the two sets of square slots. This allows the acceleration sensor to be fixed inside the protective box, preventing strong impacts and continuous vibrations from causing the acceleration sensor to fall off the pile hammer body, thereby preventing the loss or inaccuracy of detection data. This not only improves safety, but also does not increase construction costs and the risk of delays.

[0025] 2. In the present invention, by providing a reinforcement mechanism, with the cooperation of multiple groups of long screws, multiple groups of No. 1 seats, multiple groups of No. 2 seats, multiple groups of No. 1 nuts and multiple groups of No. 2 nuts, it is convenient to fix the No. 1 limiting ring and the No. 2 limiting ring, and then cooperate with four groups of semicircular blocks to limit the No. 1 semicircular plate and the No. 2 semicircular plate, thereby reinforcing the No. 1 semicircular plate and the No. 2 semicircular plate. At the same time, it can provide additional supporting force for the No. 1 semicircular plate and the No. 2 semicircular plate, thereby enhancing the overall stability of the fixing mechanism;

[0026] 3. In the present invention, through the coordinated work of multiple pressure sensors and acceleration sensors, combined with a high-speed data acquisition module and an advanced data processing and analysis module, it is possible to accurately capture subtle changes in the pile hammer impact process, thereby improving the detection accuracy of the pile hammer impact feedback frequency and providing reliable data support for the quality control of pile foundation construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a three-dimensional diagram of a pile hammer impact feedback frequency detection device for a karst cave area according to the present invention;

[0028] Figure 2 This is a front structural diagram of a pile hammer impact feedback frequency detection device for a karst cave area according to the present invention;

[0029] Figure 3 This is a structural schematic diagram of a fixing mechanism in a pile hammer impact feedback frequency detection device for a karst cave area according to the present invention;

[0030] Figure 4 This is a schematic diagram of a partially exploded structure of a fixing mechanism in a pile hammer impact feedback frequency detection device for a karst cave area according to the present invention;

[0031] Figure 5 This is a bottom view of a protective box and a first semicircular plate of a pile hammer impact feedback frequency detection device for a karst cave area according to the present invention;

[0032] Figure 6 This is a structural schematic diagram of a sealing plate and a semicircular connecting plate in a pile hammer impact feedback frequency detection device for a karst cave area according to the present invention;

[0033] Figure 7 This is a structural schematic diagram of a reinforcement mechanism used in a pile hammer impact feedback frequency detection device in a karst cave area according to the present invention;

[0034] Figure 8 This is a partial bottom view of a pile hammer impact feedback frequency detection device for a karst cave area according to the present invention;

[0035] Figure 9 This is a system diagram of a pile hammer impact feedback frequency detection device for a karst cave area according to the present invention.

[0036] In the picture:

[0037] 1. Pile hammer body; 11. Protection box; 12. Pressure sensor; 13. Acceleration sensor; 14. Latex frame; 15. Sealing plate; 16. Limiting column; 17. Limiting hole; 18. Latex plate; 2. Fixing mechanism; 20. Semicircular plate No. 1; 21. Semicircular plate No. 2; 22. Anti-slip latex pad; 23. Short screw; 24. Round hole; 25. Square groove; 26. Vertical groove; 27. Hexagonal nut; 28. Semicircular connecting plate; 29. Square hole plate; 3. Reinforcement mechanism; 30. Semicircular block; 31. Ring seat; 32. Ring plate; 33. Long screw; 34. Limiting ring No. 1; 35. Limiting ring No. 2; 36. Seat No. 1; 37. Seat No. 2; 38. Nut No. 1; 39. Nut No. 2. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] Example 1: Reference Figure 1-9 The figure shows a pile hammer impact feedback frequency detection device for use in a karst cave area, comprising a pile hammer body 1, a fixing mechanism 2 provided on the outer wall of the pile hammer body 1, a reinforcement mechanism 3 provided on the outer wall of the pile hammer body 1, a protection box 11 provided on the outer wall of the fixing mechanism 2, a pressure sensor 12 fixedly mounted in a reserved groove at the bottom of the pile hammer body 1, an acceleration sensor 13 provided inside the protection box 11, and a sealing plate 15 provided on the upper end of the protection box 11;

[0040] The fixing mechanism 2 includes a No. 1 semicircular plate 20 and a No. 2 semicircular plate 21. The outer walls of the No. 1 semicircular plate 20 and the No. 2 semicircular plate 21 are fixedly installed with anti-slip latex pads 22. One end of the No. 2 semicircular plate 21 is welded with four groups of short screws 23. One end of the No. 1 semicircular plate 20 is penetrated by four groups of circular holes 24. One end of the No. 1 semicircular plate 20 is provided with two groups of square grooves 25. The upper end of the No. 1 semicircular plate 20 is provided with a vertical groove 26. One end of the four groups of circular holes 24 is provided with two groups of hexagonal nuts 27. Semicircular connecting plates 28 are welded on both sides of the sealing plate 15. Square hole plates 29 are welded on the outer walls of the two groups of semicircular connecting plates 28. The two ends of the semicircular connecting plates 28 are respectively inserted into the interior of the two groups of vertical grooves 26. The two groups of square hole plates 29 are respectively arranged in the interior of the two groups of square grooves 25. Each short screw 23 is respectively inserted into the corresponding circular hole 2 4, and two groups of short screws 23 are respectively inserted into the interiors of the two groups of square hole plates 29, and eight groups of hexagonal nuts 27 are respectively fixed to the outer walls of the four groups of short screws 23, and the No. 1 semicircular plate 20 and the No. 2 semicircular plate 21 are in contact with the outer wall of the pile hammer body 1 through the anti-slip latex pad 22. The protective box 11 is welded to the outer wall of the No. 1 semicircular plate 20, and a latex square frame 14 is installed inside the protective box 11, and the inner wall of the latex square frame 14 is in contact with the outer wall of the acceleration sensor 13. The lower end of the sealing plate 15 is fixedly installed with a latex plate 18, and the lower end of the latex plate 18 is in contact with the upper end of the acceleration sensor 13. The lower end of the sealing plate 15 is penetrated by four groups of limiting holes 17, and the limiting columns 16 are inserted into the interiors of the four groups of limiting holes 17. The lower ends of the four groups of limiting columns 16 are fixed to the upper end of the protective box 11;

[0041] It also includes a height data acquisition module, a data processing and analysis module, a data processing and analysis module, a data storage and display module and a power management module. The pressure sensor 12 and the acceleration sensor 13 are both signal-connected to the high-speed data acquisition module, the high-speed data acquisition module is signal-connected to the data processing and analysis module, the data processing and analysis module is signal-connected to the data processing and analysis module, the pressure sensor 12, the acceleration sensor 13, the height data acquisition module, the data processing and analysis module, the data processing and analysis module and the data storage and display module are all electrically connected to the power management module.

[0042] In this embodiment, by placing the acceleration sensor 13 inside the protective box 11, and welding the protective box 11 to the outer wall of the No. 1 semicircular plate 20, the sealing plate 15 can be placed on the upper end of the protective box 11 through the plug-in cooperation of the four groups of limiting holes 17 and the four groups of limiting columns 16, so that the sealing plate 15 can be limited. During the placement of the sealing plate 15, one end of the two groups of semicircular connecting plates 28 are respectively inserted into the interior of the two groups of vertical grooves 26, and the two groups of square hole plates 29 are respectively inserted into the interior of the two groups of square grooves 25, and then the two groups of No. 1 semicircular plates 20 and No. 2 semicircular plates 2 1 is attached to the outer wall of the pile hammer body 1, and four groups of short screws 23 are respectively inserted into the inside of the four groups of round holes 24. Then, two groups of hexagonal nuts 27 are threaded on the outer walls of the four groups of short screws 23 one by one, and then the two groups of square hole plates 29 can be fixed inside the two groups of square grooves 25. In this way, the acceleration sensor 13 can be fixed inside the protection box 11, preventing strong impact and continuous vibration from causing the acceleration sensor 13 to fall off from the pile hammer body 1, and preventing the loss or inaccuracy of detection data. This not only improves safety, but also does not increase construction costs and the risk of delays.

[0043] Two sets of anti-slip latex pads 22 are respectively installed on the inner walls of the first and second semicircular plates 20, 21. This not only increases the friction with the surface of the hammer body 1, preventing the first and second semicircular plates 20, 21 from sliding, but also cushions the impact of the vibration of the hammer body 1 on the acceleration sensor 13. The fixing frame effectively prevents the loosening of the hexagonal nuts 27 caused by vibration by installing two sets of hexagonal nuts 27 on the outer wall of each short screw rod 23.

[0044] By installing the latex frame 14 inside the protective box 11 and installing the latex plate 18 at the lower end of the sealing plate 15, with the inner wall of the latex frame 14 in contact with the outer wall of the acceleration sensor 13 and the lower end of the latex plate 18 in contact with the upper end of the acceleration sensor 13, the acceleration sensor 13 can be protected to avoid damage to the acceleration sensor 13 due to hard squeezing;

[0045] The pressure sensor 12 is arranged in the reserved groove at the bottom of the pile hammer body 1 and is used to accurately measure the pressure changes generated during the impact process and obtain the mechanical information of the pile hammer during impact;

[0046] The acceleration sensor 13 is installed in the protection box 11. A high-sensitivity, wide-band response model can be selected to monitor the acceleration changes during the impact of the pile hammer in real time.

[0047] High-speed data acquisition module: This module is responsible for collecting analog signals from sensors and converting them into digital signals. Equipped with a high-speed sampling chip, the sampling frequency can be flexibly adjusted between 5kHz and 50kHz according to actual construction requirements, ensuring accurate recording of signal changes at the moment of pile hammer impact. The multi-channel synchronous acquisition function ensures the consistency of data from each sensor.

[0048] Data processing and analysis module: uses a high-performance digital signal processor (DSP) or field programmable gate array (FPGA) chip to process the collected digital signals in real time, removes noise interference in the signals through filtering algorithms, and uses spectrum analysis methods such as fast Fourier transform (FFT) to extract key characteristic parameters such as the pile hammer impact feedback frequency;

[0049] Data storage and display module: This module stores processed data in a large-capacity solid-state drive (SSD) or flash memory card to facilitate subsequent query and analysis. It is also equipped with an LCD screen that displays important parameters such as the hammer impact feedback frequency and impact times in real time, allowing construction personnel to intuitively understand the construction status.

[0050] Power management module: Provides a stable power supply for the entire detection device. It uses a rechargeable lithium battery pack as a power source and is equipped with an external power adapter to meet the usage requirements in different scenarios. The power management module has overcharge and over-discharge protection functions to extend the battery life.

[0051] Example 2: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 7 and Figure 8 As shown, the reinforcement mechanism 3 includes a circular seat 31, and the upper and lower ends of the No. 1 semicircular plate 20 and the No. 2 semicircular plate 21 are welded with semicircular blocks 30. The upper end of the circular seat 31 is welded with a circular plate 32, and the lower end of the circular plate 32 is welded with multiple groups of long screws 33. The upper and lower ends of the No. 1 semicircular plate 20 are respectively provided with a No. 1 limiting ring 34 and a No. 2 limiting ring 35. The outer wall of the No. 1 limiting ring 34 is welded with multiple groups of No. 1 seats 36, and the outer wall of the No. 2 limiting ring 35 is welded with multiple groups of No. 1 seats. Multiple groups of No. 2 seats 37 are welded to the wall. The outer walls of multiple groups of long screws 33 are threadedly connected with No. 1 nuts 38 and No. 2 nuts 39 from top to bottom. The outer walls of each two groups of semicircular blocks 30 are in contact with the inner walls of No. 1 limiting ring 34 and No. 2 limiting ring 35. One end of each group of long screws 33 is inserted into the interior of No. 1 seat 36 and No. 2 seat 37 in sequence. The annular seat 31 is sleeved on the outer wall of the pile hammer body 1, and the lower end of the annular plate 32 is in contact with the upper end of the pile hammer body 1.

[0052] In this embodiment, four groups of semicircular blocks 30 are respectively welded to the upper and lower ends of two groups of No. 1 semicircular plates 20 and No. 2 semicircular plates 21, and then multiple groups of No. 1 nuts 38 are respectively threaded on multiple groups of long screws 33, and No. 1 limiting rings 34 are sleeved on the outer walls of two groups of semicircular blocks 30, and No. 2 limiting rings 35 are sleeved on the outer walls of the other two groups of semicircular blocks 30. After that, the annular plate 32 is placed on the upper end of the pile hammer body 1, and the inner wall of the annular seat 31 contacts the outer wall of the pile hammer body 1, during which multiple groups of long screws 33 are respectively inserted into the No. 1 seat matched therewith. 36 and the interior of the No. 2 seat 37, and then multiple groups of No. 2 nuts 39 are respectively threaded on the outer walls of the multiple groups of long screws 33, and then multiple groups of No. 1 nuts 38 and No. 2 nuts 39 are tightened one by one, so that they are in close contact with the multiple groups of No. 1 seats 36 and No. 2 seats 37, respectively, and then the No. 1 semicircular plate 20 and the No. 2 semicircular plate 21 can be limited, so that the No. 1 semicircular plate 20 and the No. 2 semicircular plate 21 can be reinforced. At the same time, additional supporting force can be provided to the No. 1 semicircular plate 20 and the No. 2 semicircular plate 21, thereby enhancing the overall stability of the fixing mechanism 2.

[0053] A method for detecting a pile hammer impact feedback frequency in a karst cave area comprises the following steps:

[0054] S1. Device Installation and Initialization: Install the acceleration sensor 13 inside the protective box 11 according to the design requirements, and the pressure sensor 12 in the reserved groove at the bottom of the pile hammer body 1 according to the design requirements, and ensure that the connections are secure. Initialize the high-speed data acquisition module, data processing and analysis module, and data storage and display module, including the sampling frequency, filter parameters, storage path, etc.

[0055] S2. Data acquisition: When the hammer body 1 performs an impact operation, the high-speed data acquisition module synchronously collects the signals output by the acceleration sensor 13 and the pressure sensor 12, converts them into digital signals through the data processing and analysis module, and stores them in the data storage and display module. The acquisition process should last for a period of time to obtain sufficient impact data samples;

[0056] S3. Data preprocessing: Preprocess the collected raw data, including noise removal and baseline correction. Digital filtering algorithms, such as Butterworth filters, can be used to remove high-frequency noise and low-frequency interference in the signal.

[0057] S4. Feature extraction: Analyze the pre-processed data using spectrum analysis methods, such as Fast Fourier Transform (FFT), to obtain a spectrum of the signal. Extract the impact feedback frequency of the hammer body 1 from the spectrum, which can be determined by finding the peak frequency in the spectrum.

[0058] S5. Result Analysis and Evaluation: Based on the extracted impact feedback frequency, combined with factors such as the geological conditions of the karst cave area and the design parameters of the pile, the impact effect of the pile hammer body 1 and the bearing capacity of the pile foundation are analyzed. For example, if the impact feedback frequency shows abnormal changes, it means that the pile bottom has encountered a karst cave or other geological defects, requiring further investigation and analysis.

[0059] S6. Data storage and report generation: The processed data and analysis results are stored in the storage module, and a detailed test report is generated. The report should include information such as the test time, location, pile number, impact feedback frequency, as well as analysis and suggestions on the test results.

[0060] The working principle of the present invention is as follows: First, when in use, the acceleration sensor 13 is placed inside the protective box 11, and then the sealing plate 15 is picked up and placed on the upper end of the protective box 11. The sealing plate 15 will drive the two sets of semicircular connecting plates 28 and the two sets of square hole plates 29 to move together. The two sets of semicircular connecting plates 28 are respectively inserted into the interior of the vertical slots 26, and the two sets of square hole plates 29 are inserted into the interior of the two sets of square slots 25. After that, the first semicircular plate 20 and the second semicircular plate 21 are picked up and moved so that they are both toward the pile hammer body 1. The outer walls are brought closer together until the inner walls of the two sets of anti-slip latex pads 22 contact the outer wall of the pile hammer body 1, and the four sets of short screws 23 at one end of the second semicircular plate 21 are respectively inserted into the interiors of the four circular holes 24, during which two sets of short screws 23 are inserted into the interiors of the two sets of square hole plates 29. Then, two sets of hexagonal nuts 27 are threaded onto the outer walls of the four sets of short screws 23 one by one, thereby fixing the first and second semicircular plates 20, 21 to the outer wall of the pile hammer body 1, and the sealing plate 15 is fixed to the upper end of the protective box 11.

[0061] Then, the No. 1 limiting ring 34 is put on the outer walls of two groups of semicircular blocks 30, and the No. 2 limiting ring 35 is put on the outer walls of the other two groups of semicircular blocks 30. Then, the circular ring seat 31 is picked up and the circular ring seat 31 is put on the outer wall of the pile hammer body 1, and the multiple groups of long screws 33 are respectively inserted into the interior of the multiple groups of No. 1 seats 36 and No. 2 seats 37 until the lower ends of the circular ring plates 32 contact the upper ends of the pile hammer body 1, and the multiple groups of No. 2 nuts 39 are respectively threaded on the outer walls of the multiple groups of long screws 33. After that, by tightening the multiple groups of No. 1 nuts 38 and No. 2 nuts 39 one by one, the multiple groups of No. 1 nuts 38 and No. 2 nuts 39 are respectively threaded on the outer walls of the multiple groups of long screws 33 until the multiple groups of No. 1 nuts 38 and No. 2 nuts 39 are respectively in contact with the No. 1 seat 36 and No. 2 seat 37, so that the No. 1 semicircular plate 20 and the No. 2 semicircular plate 21 can be limited.

[0062] Finally, the pile hammer body 1 is installed on the impact device, and the impact device is operated to drive the pile hammer body 1 to impact downward. The pile hammer body 1 will drive the pressure sensor 12 and the acceleration sensor 13 to move downward, and the pressure sensor 12 will contact the pile column. The data measured by the two during this period will be transmitted to the height data acquisition module, and in conjunction with the data processing and analysis module and the data storage and display module, it can accurately capture the subtle changes in the pile hammer impact process, improve the detection accuracy of the pile hammer impact feedback frequency, and provide reliable data support for the quality control of pile foundation construction.

[0063] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pile hammer impact feedback frequency detection device for a karst cave area, comprising a pile hammer body (1), characterized in that: The outer wall of the pile hammer body (1) is provided with a fixing mechanism (2), the outer wall of the pile hammer body (1) is provided with a reinforcement mechanism (3), the outer wall of the fixing mechanism (2) is provided with a protection box (11), a pressure sensor (12) is fixedly installed in a reserved groove at the bottom of the pile hammer body (1), an acceleration sensor (13) is provided inside the protection box (11), and a sealing plate (15) is provided at the upper end of the protection box (11); The fixing mechanism (2) comprises a No. 1 semicircular plate (20) and a No. 2 semicircular plate (21), the outer walls of the No. 1 semicircular plate (20) and the No. 2 semicircular plate (21) are fixedly mounted with anti-skid latex pads (22), one end of the No. 2 semicircular plate (21) is welded with four groups of short screws (23), one end of the No. 1 semicircular plate (20) is penetrated with four groups of circular holes (24), one end of the No. 1 semicircular plate (20) is provided with two groups of square grooves (25), the upper end of the No. 1 semicircular plate (20) is provided with a vertical groove (26), one end of the four groups of circular holes (24) are provided with two groups of hexagonal nuts (27), both sides of the sealing plate (15) are welded with semicircular connecting plates (28), and the outer walls of the two groups of semicircular connecting plates (28) are welded with square hole plates (29); It also includes a height data acquisition module, a data processing and analysis module, a data processing and analysis module, a data storage and display module and a power management module. The pressure sensor (12) and the acceleration sensor (13) are both connected to the high-speed data acquisition module by signal, the high-speed data acquisition module is connected to the data processing and analysis module by signal, the data processing and analysis module is connected to the data processing and analysis module by signal, and the pressure sensor (12), the acceleration sensor (13), the height data acquisition module, the data processing and analysis module, the data processing and analysis module and the data storage and display module are all electrically connected to the power management module.

2. The device for detecting the impact feedback frequency of a pile hammer in a karst cave area according to claim 1, characterized in that: A latex frame (14) is installed inside the protection box (11), and the inner wall of the latex frame (14) contacts the outer wall of the acceleration sensor (13). A latex plate (18) is fixedly installed at the lower end of the sealing plate (15).

3. The device for detecting the impact feedback frequency of a pile hammer in a karst cave area according to claim 1, characterized in that: The reinforcing mechanism (3) comprises a circular ring seat (31), the upper and lower ends of the No. 1 semicircular plate (20) and the No. 2 semicircular plate (21) are both welded with semicircular blocks (30), the upper end of the circular ring seat (31) is welded with a circular ring plate (32), the lower end of the circular ring plate (32) is welded with multiple groups of long screws (33), the upper and lower ends of the No. 1 semicircular plate (20) are respectively provided with a No. 1 limiting circular ring (34) and a No. 2 limiting circular ring (35), the outer wall of the No. 1 limiting circular ring (34) is welded with multiple groups of No. 1 seats (36), the outer wall of the No. 2 limiting circular ring (35) is welded with multiple groups of No. 2 seats (37), and the outer walls of the multiple groups of the long screws (33) are sequentially threadedly connected with a No. 1 nut (38) and a No. 2 nut (39) from top to bottom.

4. The device for detecting the impact feedback frequency of a pile hammer in a karst cave area according to claim 1, characterized in that: The two ends of the semicircular connecting plate (28) are respectively inserted into the interior of the two groups of vertical grooves (26), the two groups of square hole plates (29) are respectively arranged in the interior of the two groups of square grooves (25), and each of the short screw rods (23) is respectively inserted into the interior of the corresponding circular hole (24), and one end of the two groups of short screw rods (23) is respectively inserted into the interior of the two groups of square hole plates (29).

5. The device for detecting the impact feedback frequency of a pile hammer in a karst cave area according to claim 4, characterized in that: The eight groups of hexagonal nuts (27) are respectively fixed to the outer walls of the four groups of short screws (23); the first semicircular plate (20) and the second semicircular plate (21) are in contact with the outer wall of the pile hammer body (1) via the anti-skid latex pad (22); and the protective box (11) is welded to the outer wall of the first semicircular plate (20).

6. The device for detecting the impact feedback frequency of a pile hammer in a karst cave area according to claim 3, characterized in that: The outer walls of each two groups of semicircular blocks (30) are in contact with the inner walls of the No. 1 limiting ring (34) and the No. 2 limiting ring (35), and one end of each group of long screws (33) is inserted into the interior of the No. 1 seat (36) and the No. 2 seat (37) in sequence.

7. The device for detecting the impact feedback frequency of a pile hammer in a karst cave area according to claim 6, characterized in that: The annular seat (31) is sleeved on the outer wall of the pile hammer body (1), and the lower end of the annular plate (32) contacts the upper end of the pile hammer body (1).

8. The device for detecting the impact feedback frequency of a pile hammer in a karst cave area according to claim 2, characterized in that: The lower end of the latex plate (18) contacts the upper end of the acceleration sensor (13), and the lower end of the sealing plate (15) is penetrated by four groups of limiting holes (17).

9. The device for detecting the impact feedback frequency of a pile hammer in a karst cave area according to claim 8, characterized in that: The limiting columns (16) are inserted into the interiors of the four groups of limiting holes (17), and the lower ends of the four groups of limiting columns (16) are fixed to the upper end of the protection box (11).

10. A method for detecting the frequency of a pile hammer impact feedback device in a karst cave area, characterized in that: The device for detecting the impact feedback frequency of a pile hammer in a karst cave area according to any one of claims 1 to 9 comprises the following steps: S1. Device installation and initialization: Install the acceleration sensor (13) inside the protective box (11) according to the design requirements, and install the pressure sensor (12) in the reserved groove at the bottom of the pile hammer body (1) according to the design requirements, and ensure that the connection is firm. Initialize the high-speed data acquisition module, data processing and analysis module, and data storage and display module, including sampling frequency, filter parameters, storage path, etc. S2. Data acquisition: When the pile hammer body (1) performs an impact operation, the high-speed data acquisition module synchronously acquires the signals output by the acceleration sensor (13) and the pressure sensor (12), converts them into digital signals through the data processing and analysis module, and stores them in the data storage and display module. The acquisition process should last for a period of time to obtain enough impact data samples; S3. Data preprocessing: Preprocess the collected raw data, including noise removal and baseline correction. Digital filtering algorithms, such as Butterworth filters, can be used to remove high-frequency noise and low-frequency interference in the signal. S4. Feature extraction: Analyze the pre-processed data using spectrum analysis methods, such as fast Fourier transform (FFT), to obtain a spectrum of the signal. Extract the impact feedback frequency of the hammer body (1) from the spectrum, which can be determined by finding the peak frequency in the spectrum. S5. Result analysis and evaluation: Based on the extracted impact feedback frequency, combined with the geological conditions of the cave area, the design parameters of the pile and other factors, the impact effect of the pile hammer body (1) and the bearing capacity of the pile foundation are analyzed; S6. Data storage and report generation: The processed data and analysis results are stored in the storage module, and a detailed test report is generated. The report should include information such as the test time, location, pile number, impact feedback frequency, as well as analysis and suggestions on the test results.

Images