Discrete sound wave tomography method for pile body integrity detection

Abstract

The invention relates to the field of pile body detection, in particular to a discrete acoustic tomography method for pile body integrity detection, which comprises the steps of deployment and establishment of a detection environment, data acquisition of acoustic waves and electromagnetic waves, data processing and model calculation. According to the method, the sensor is deployed in the sounding pipe to form double physical constraints of an acoustic wave velocity field and a dielectric constant field, high-confidence distinguishing and accurate diagnosis of internal defects of the cast-in-place pile are achieved, misjudgment of traditional single parameter detection is effectively avoided, and the pile body integrity detection precision is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pile body detection technology, and particularly relates to a discrete acoustic tomography method for pile body integrity detection. BACKGROUND

[0002] The pile body integrity detection technology widely used in engineering at present, such as cross-hole acoustic transmission method and acoustic tomography, has some defects in practical application. Some traditional detection methods can only provide one-dimensional evaluation curve along the depth direction, so the qualitative differentiation ability is poor. In addition, the dependence on acoustic parameters also causes the loss of defect physical property information, and the integrity detection effect is poor. Therefore, it is urgent to solve the problem. SUMMARY

[0003] The present application relates to the field of pile body detection technology, and particularly relates to a discrete acoustic tomography method for pile body integrity detection.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0005] A discrete acoustic tomography method for pile body integrity detection, comprising the following steps:

[0006] S1, deployment and establishment of detection environment;

[0007] A, establishing a detection channel around or inside the target pile (including the original pre-buried acoustic pipe), and dividing the detection pile body into 15-25 horizontal layers at the same interval, and making independent two-dimensional tomography groups based on each horizontal layer;

[0008] B, sensor deployment, including deploying acoustic sensors, electromagnetic wave sensors and high-frequency ground penetrating radar in the acoustic pipe;

[0009] C, data integration and control based on S1-B, specifically connecting the signals of the device acoustic wave and electromagnetic wave sensors to the central control system through the data acquisition system, realizing synchronous triggering, time-sharing acquisition and real-time data transmission;

[0010] S2, data acquisition of acoustic wave and electromagnetic wave;

[0011] A, acoustic data acquisition, specifically manually operating the acoustic transducer to move it to the corresponding horizontal layer divided in S1-A by the lifting device, with an alignment error of not more than 1-3 cm, and then sending a trigger pulse to the target by the central control system, exciting the source to generate acoustic waves, and the receiver synchronously receiving the acoustic wave signals passing through the concrete;

[0012] B, acoustic data recording, specifically recording the complete waveform of each path by the central control system, and technicians extract, measure and import the waveform.

[0013] C. Electromagnetic wave data collection, specifically by manual operation, placing the electromagnetic wave antenna into the sounding pipe, maintaining a speed of 3-5 m / min, scanning, wherein the high-frequency electromagnetic wave pulses emitted by the antenna to the interior of the pile concrete are recorded by the central control system at a depth of 5-10 cm as a recording interval, and the reflected wave waveform is recorded;

[0014] D. Manual electromagnetic wave data arrangement, and importing electromagnetic wave data into the central control system;

[0015] S3. Data processing and model calculation;

[0016] A. Sound wave data processing, specifically based on the arrival time of the sound wave first wave, using an algorithm to calculate the residual error between the theoretical propagation time and the actual measured time, and performing 10-20 iterations until the final residual rate between the theoretical propagation time and the actual measured time is less than 3-5%, until the corresponding sound wave graph of the pile cross section is reached;

[0017] B. System analysis of electromagnetic wave data to generate a two-dimensional image of the dielectric constant distribution of the pile cross section;

[0018] C. Dual parameter fusion inversion, the central control system inputs the two data obtained in S3-A, B as double constraint conditions into the fusion inversion algorithm, which must minimize the residual error of the wave velocity model and the dielectric constant model in each iteration, and optimizes 25-35 times to solve the final defect distribution index field;

[0019] D. High confidence defect determination by the central control system, the central control system sets double determination thresholds based on the fusion index field, only when the wave velocity value of the grid unit is lower than the qualified threshold and its dielectric constant value exceeds the normal range, it is automatically marked by the system as a high confidence structural defect.

[0020] E. Manual review of high confidence defect areas determined by the system by engineers, combining the degree of wave velocity reduction and the degree of dielectric constant abnormality to qualitatively describe the defect type.

[0021] Preferably, the sound wave sensor is deployed in the sounding pipe, a high-frequency, high-bandwidth sound wave transducer is selected, including an excitation source and a receiver, and the excitation source and the receiver are pre-buried in the sounding pipe.

[0022] Preferably, the antenna of the high-frequency ground penetrating radar antenna is synchronously deployed in the sounding pipe with the sound wave sensor, and the antenna operating frequency must penetrate the concrete and be sensitive to defects such as internal cavities and water-containing cracks in the pile.

[0023] Preferably, when the sound wave transducer is installed by the lifting device, the operator should clean and fill water in all the sounding pipes, and the water level should be higher than the top of the pile.

[0024] Preferably, in the S2 step, after 5-7 horizontal layers are collected, the operator should randomly select 1-3 horizontal layers for secondary repeated measurement, and the relative deviation of the first wave arrival time of the sound wave in the two measurements should be less than 2-3%.

[0025] Preferably, in the S3 step, cross calibration should be performed by using the sound wave and electromagnetic wave sensors to ensure that the error of the sound wave pulse excitation position and the electromagnetic wave scanning position in the vertical depth is not more than 0.1-0.3 cm.

[0026] Preferably, when the operator cleans and fills water in all the sounding pipes, the water temperature in the pipes should be detected every 3-5 h.

[0027] Preferably, when the ground penetrating radar performs continuous depth scanning, the sensor should be lowered independently, and the lowering speed should be maintained at 2-4 m / min.

[0028] Preferably, the cable used for deploying the sensor should be a low-noise and high-shield data line, and the cable should be prevented from being entangled or twisted during the deployment process to prevent the generation of capacitive coupling noise.

[0029] Preferably, during the deployment process, the antenna should be kept stable and vertical to avoid shaking or tilting in the pipe and to maintain a uniform gap with the pipe wall.

[0030] The beneficial effects of the present application are:

[0031] In the present application, the sensor is deployed inside the sounding pipe to form a double physical constraint of the sound wave velocity field and the dielectric constant field, which realizes high-confidence differentiation and accurate diagnosis of internal defects of the cast-in-place pile, effectively avoids the misjudgment of traditional single parameter detection, and significantly improves the detection accuracy of the pile body integrity. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments.

[0033] Embodiment 1

[0034] A discrete sound wave tomography method for pile body integrity detection, comprising the following steps:

[0035] S1, deployment and establishment of the detection environment;

[0036] A, Establish detection channels around or inside the target pile (including the original pre-buried sounding pipe), and divide the detection pile body into 15 horizontal layers at the same interval, and make independent two-dimensional tomographic imaging groups respectively based on each horizontal layer;

[0037] B, Sensor deployment, including deploying acoustic wave sensors, electromagnetic wave sensors, and high-frequency geological radar in the sounding pipe;

[0038] C, Data integration and control based on S1-B, specifically connecting the signals of the device acoustic wave and electromagnetic wave sensors to the central control system through the data acquisition system, realizing synchronous triggering, time-sharing acquisition, and real-time data transmission;

[0039] S2, Acoustic wave and electromagnetic wave data acquisition;

[0040] A, Acoustic wave data acquisition, specifically manually moving the acoustic wave transducer to the corresponding horizontal layer divided in S1-A by the lifting device, with an alignment error of not more than 1 cm, and then sending a trigger pulse to the target by the central control system, exciting the source to generate acoustic waves, and the receiver synchronously receiving the acoustic wave signals passing through the concrete;

[0041] B, Acoustic wave data recording, specifically recording the complete waveform of each path by the central control system, and technicians extracting, measuring, and importing the waveform;

[0042] C, Electromagnetic wave data acquisition, specifically manually placing the electromagnetic wave antenna in the sounding pipe, maintaining a speed of 3 m / min for scanning, and recording the reflected wave waveform at a depth of every 5 cm as a recording interval by the central control system;

[0043] D, Manual electromagnetic wave data arrangement, and importing electromagnetic wave data into the central control system;

[0044] S3, Data processing and model calculation;

[0045] A, Acoustic wave data processing, specifically using the central control system to calculate the residual error between the theoretical propagation time and the actual measured time based on the acoustic wave first arrival time, and executing 10 iterations until the final residual rate between the theoretical propagation time and the actual measured time is less than 3%, and until the corresponding acoustic wave image of the pile cross section is reached;

[0046] B, System analysis of electromagnetic wave data to generate a two-dimensional image of the dielectric constant distribution of the pile cross section;

[0047] C. Two-parameter fusion inversion is performed, and the central control system inputs the two data obtained in S3-A and S3-B as double constraints into the fusion inversion algorithm. In each iteration, the algorithm must minimize the residual of the wave velocity model and the residual of the dielectric constant model at the same time, and through 25-35 iterations of optimization, the final defect distribution index field is solved;

[0048] D. High placement judgment of defects is performed by the central control system. The central control system sets double judgment thresholds according to the fusion index field. Only when the wave velocity value of the grid unit is lower than the qualified threshold and the dielectric constant value thereof is out of the normal range, the grid unit is automatically marked as a high-confidence structural defect by the system.

[0049] E. The high-confidence defect area determined by the system is manually reviewed by an engineer, and the defect type is qualitatively described in combination with the wave velocity reduction degree and the dielectric constant abnormality degree.

[0050] In S2, after every 5 horizontal layers of collection are completed, the operator should randomly select 1 horizontal layer for secondary repeated measurement, and the relative deviation of the first arrival time of the sound wave in the two measurements should be less than 2%.

[0051] In S3, cross calibration must be performed using the sound wave and electromagnetic wave sensors to ensure that the error of the sound wave pulse excitation position and the electromagnetic wave scanning position in the vertical depth is not more than 0.1 cm.

[0052] Further, when the operator brushes all the sounding pipes and fills the pipes with water, the water temperature in the pipe should be detected every 3 h.

[0053] Further, when the ground penetrating radar performs continuous depth scanning, the sensor should be lowered independently at a speed of every 2 m / min.

[0054] Example 2

[0055] A discrete sound wave tomography method for pile body integrity detection, comprising the following steps:

[0056] S1, deployment and establishment of the detection environment;

[0057] A. Establish a detection channel around or inside the target pile (including the original pre-buried sounding pipe), and divide the detection pile into 20 horizontal layers at the same interval, and make independent two-dimensional tomography groups based on each horizontal layer;

[0058] B. Sensor deployment, including deployment of sound wave sensors, electromagnetic wave sensors, and high-frequency ground penetrating radar in the sounding pipe;

[0059] C. Data integration and control are carried out based on S1-B. Specifically, the signals of the equipment's acoustic and electromagnetic wave sensors are connected to the central control system through the data acquisition system to achieve synchronous triggering, time-sharing acquisition, and real-time data transmission.

[0060] S2. Data acquisition of sound waves and electromagnetic waves;

[0061] A. Acoustic data acquisition is carried out manually. The acoustic transducer is moved to the corresponding horizontal layer divided in S1-A by a lifting device with an alignment error of no more than 2cm. Then, the central control system sends a trigger pulse to the target, the excitation source generates sound waves, and the receiver synchronously receives the sound wave signal passing through the concrete.

[0062] B. Acoustic wave data recording: Specifically, the central control system records the complete waveform of each path, and technicians extract, measure, and import the waveforms.

[0063] C. Electromagnetic wave data acquisition is carried out manually. The electromagnetic wave antenna is placed inside the sonic logging tube and lowered at a speed of 4 m / min for scanning. The high-frequency electromagnetic wave pulses emitted by the antenna into the concrete of the pile are recorded by the central control system at a recording interval of 7.5 cm.

[0064] D. Manually organize the electromagnetic wave data and import it into the central control system;

[0065] S3, Data Processing and Model Calculation;

[0066] A. Acoustic data processing: The central control system uses the arrival time of the first wave of the acoustic wave as a basis to calculate the residual between the theoretical propagation time and the actual measurement time using an algorithm. The process is repeated 15 times until the final residual rate between the theoretical propagation time and the actual measurement time is less than 4%, until the corresponding acoustic waveform of the pile section is obtained.

[0067] B. The system analyzes electromagnetic wave data and generates a two-dimensional image of the dielectric constant distribution of the pile cross section;

[0068] C. Perform dual-parameter fusion inversion. The central control system inputs the two data obtained from S3-A and B as dual constraints into the fusion inversion algorithm. In each iteration, the algorithm must simultaneously minimize the residuals of the wave velocity model and the dielectric constant model. Through 30 iterations of optimization, the final defect distribution index field is solved.

[0069] D. The central control system makes high-confidence judgments on defects. Based on the fusion index field, the central control system sets dual judgment thresholds. Only when the wave velocity value of the grid cell is lower than the qualified threshold and its dielectric constant value exceeds the normal range will it be automatically marked as a high-confidence structural defect by the system.

[0070] E. Engineers manually review the high-confidence defect areas identified by the system, and qualitatively describe the defect type by combining the degree of wave velocity reduction and the degree of dielectric constant abnormality.

[0071] In step S2, after collecting data from every 6 horizontal layers, the operator should randomly select 2 horizontal layers for a second, repeated measurement. The relative deviation between the arrival times of the first wave of the sound wave in the two measurements should be less than 2.5%.

[0072] Located in S3, cross-calibration must be performed using acoustic and electromagnetic wave sensors to ensure that the error between the excitation position of the acoustic pulse and the scanning position of the electromagnetic wave in the vertical depth does not exceed 0.2 cm.

[0073] Furthermore, when operators clean all sonic logging pipes and fill them with water, they should check the water temperature inside the pipes every 4 hours.

[0074] Furthermore, during continuous depth scanning with ground-penetrating radar, the sensors should be lowered independently at a speed of 3 m / min.

[0075] Example 3

[0076] A discrete acoustic tomography method for pile integrity detection includes the following steps:

[0077] S1. Deployment and establishment of the testing environment;

[0078] A. Establish a detection channel around or inside the target pile (including inside the original pre-embedded sonic logging pipe), and divide the detection pile into 25 horizontal layers at the same interval, and make an independent two-dimensional tomography group based on each horizontal layer.

[0079] B. Deploy sensors, including acoustic sensors, electromagnetic sensors, and high-frequency ground-penetrating radar in acoustic logging tubes;

[0080] C. Data integration and control are carried out based on S1-B. Specifically, the signals of the equipment's acoustic and electromagnetic wave sensors are connected to the central control system through the data acquisition system to achieve synchronous triggering, time-sharing acquisition, and real-time data transmission.

[0081] S2. Data acquisition of sound waves and electromagnetic waves;

[0082] A. Acoustic data acquisition is carried out manually. The acoustic transducer is moved to the corresponding horizontal layer divided in S1-A by a lifting device with an alignment error of no more than 3cm. Then, the central control system sends a trigger pulse to the target, the excitation source generates sound waves, and the receiver synchronously receives the sound wave signal passing through the concrete.

[0083] B. Acoustic wave data recording: Specifically, the central control system records the complete waveform of each path, and technicians extract, measure, and import the waveforms.

[0084] C. Electromagnetic wave data acquisition is carried out manually. The electromagnetic wave antenna is placed inside the sonic logging tube and lowered at a speed of 5m / min for scanning. The high-frequency electromagnetic wave pulses emitted by the antenna into the concrete of the pile are recorded by the central control system at a recording interval of 10cm.

[0085] D. Manually organize the electromagnetic wave data and import it into the central control system;

[0086] S3, Data Processing and Model Calculation;

[0087] A. Acoustic data processing: The central control system uses the arrival time of the first wave of the acoustic wave as a basis to calculate the residual between the theoretical propagation time and the actual measurement time using an algorithm. The process is repeated 20 times until the final residual rate between the theoretical propagation time and the actual measurement time is less than 5%, until the corresponding acoustic waveform of the pile section is obtained.

[0088] B. The system analyzes electromagnetic wave data and generates a two-dimensional image of the dielectric constant distribution of the pile cross section;

[0089] C. Perform dual-parameter fusion inversion. The central control system inputs the two data obtained from S3-A and B as dual constraints into the fusion inversion algorithm. In each iteration, the algorithm must simultaneously minimize the residuals of the wave velocity model and the dielectric constant model. Through 35 iterations of optimization, the final defect distribution index field is solved.

[0090] D. The central control system makes high-confidence judgments on defects. Based on the fusion index field, the central control system sets dual judgment thresholds. Only when the wave velocity value of the grid cell is lower than the qualified threshold and its dielectric constant value exceeds the normal range will it be automatically marked as a high-confidence structural defect by the system.

[0091] E. Engineers manually review the high-confidence defect areas identified by the system, and qualitatively describe the defect type by combining the degree of wave velocity reduction and the degree of dielectric constant abnormality.

[0092] In step S2, after collecting data from every 7 horizontal layers, the operator should randomly select 3 horizontal layers for a second, repeated measurement. The relative deviation of the arrival time of the first wave of the sound wave between the two measurements should be less than 3%.

[0093] Located in S3, cross-calibration must be performed using acoustic and electromagnetic wave sensors to ensure that the error between the excitation position of the acoustic pulse and the scanning position of the electromagnetic wave in the vertical depth does not exceed 0.3 cm.

[0094] Furthermore, when operators clean all sonic logging pipes and fill them with water, they should check the water temperature inside the pipes every 5 hours.

[0095] Furthermore, during continuous depth scanning with ground-penetrating radar, the sensors should be lowered independently at a speed of 4 m / min.

[0096] Among them, acoustic wave sensors are deployed in the acoustic logging tube, and high-frequency, high-bandwidth acoustic wave transducers are selected, including excitation sources and receivers, which are pre-embedded in the acoustic logging tube.

[0097] In addition, the antenna of the high-frequency ground-penetrating radar antenna is deployed synchronously with the acoustic sensor inside the acoustic tube. The antenna's operating frequency must penetrate the concrete and be sensitive to defects such as cavities and water-bearing cracks inside the pile.

[0098] In addition, when installing the acoustic transducer using a lifting device, the operator should clean all the acoustic logging pipes and fill them with water, ensuring the water level is above the top of the pile.

[0099] The cables used for sensor deployment must be low-noise, highly shielded data cables. During deployment, avoid tangling or twisting the cables to prevent capacitive coupling noise.

[0100] During deployment, ensure the antenna remains stable and vertical, avoiding shaking or tilting inside the tube, and maintain a uniform gap with the tube wall.

[0101] In this embodiment, a detection channel is established around the target pile, which is divided into multiple horizontal layers and equipped with devices such as acoustic wave sensors, electromagnetic wave sensors and high-frequency ground radar. Synchronous triggering and time-sharing acquisition are achieved through a central control system. Then, the acoustic transducer is manually operated to the corresponding horizontal layer, and the system records the complete waveform of the acoustic wave and the arrival time of the first wave.

[0102] Simultaneously, the electromagnetic wave antenna is manually lowered for scanning, and the system then imports all the data into the central control system. The system performs multiple iterations of algorithm processing on the acoustic wave data to generate an acoustic wave diagram of the pile cross section, and simultaneously analyzes the electromagnetic wave data to generate a dielectric constant distribution diagram.

[0103] The system inputs both as dual constraints into the fusion algorithm. Through multiple iterations of optimization, it minimizes the residuals of the sound velocity and dielectric constant models simultaneously, and solves for the final defect distribution index field. Finally, the central control system sets dual thresholds based on the fusion index field to make a high-confidence judgment, automatically marking structural defects. Engineers then manually review and qualitatively describe the defects by combining the degree of anomaly in wave velocity and dielectric constant.

[0104] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A discrete acoustic tomography method for pile integrity detection, characterized in that, Includes the following steps: S1. Deployment and establishment of the testing environment; A. Establish a detection channel around or inside the target pile (including inside the original pre-embedded sonic logging pipe), and divide the detection pile into 15-25 horizontal layers at the same interval, and make an independent two-dimensional tomography group based on each horizontal layer. B. Deploy sensors, including acoustic sensors, electromagnetic sensors, and high-frequency ground-penetrating radar in acoustic logging tubes; C. Data integration and control are carried out based on S1-B. Specifically, the signals of the equipment's acoustic and electromagnetic wave sensors are connected to the central control system through the data acquisition system to achieve synchronous triggering, time-sharing acquisition, and real-time data transmission. S2. Data acquisition of sound waves and electromagnetic waves; A. Acoustic data acquisition is carried out manually. The acoustic transducer is moved to the corresponding horizontal layer divided in S1-A by a lifting device. The alignment error does not exceed 1-3cm. Then, the central control system sends a trigger pulse to the target, the excitation source generates sound waves, and the receiver synchronously receives the sound wave signal passing through the concrete. B. Acoustic wave data recording: Specifically, the central control system records the complete waveform of each path, and technicians extract, measure, and import the waveforms. C. Electromagnetic wave data acquisition is carried out manually. The electromagnetic wave antenna is placed inside the sonic logging tube and lowered at a speed of 3-5 m / min for scanning. The high-frequency electromagnetic wave pulses emitted by the antenna into the concrete of the pile are recorded by the central control system at a recording interval of 5-10 cm. D. Manually organize the electromagnetic wave data and import it into the central control system; S3, Data Processing and Model Calculation; A. Acoustic data processing: The central control system uses the arrival time of the first wave of the acoustic wave as a basis to calculate the residual between the theoretical propagation time and the actual measurement time using an algorithm. The process is repeated 10-20 times until the final residual rate between the theoretical propagation time and the actual measurement time is less than 3-5%, until the corresponding acoustic waveform of the pile section is obtained. B. The system analyzes electromagnetic wave data and generates a two-dimensional image of the dielectric constant distribution of the pile cross section; C. Perform dual-parameter fusion inversion. The central control system inputs the two data obtained from S3-A and B as dual constraints into the fusion inversion algorithm. In each iteration, the algorithm must simultaneously minimize the residuals of the wave velocity model and the dielectric constant model. Through 25-35 iterations of optimization, the final defect distribution index field is solved. D. The central control system makes high-confidence judgments on defects. Based on the fusion index field, the central control system sets dual judgment thresholds. Only when the wave velocity value of the grid cell is lower than the qualified threshold and its dielectric constant value exceeds the normal range will it be automatically marked as a high-confidence structural defect by the system. E. Engineers manually review the high-confidence defect areas identified by the system, and qualitatively describe the defect type by combining the degree of wave velocity reduction and the degree of dielectric constant abnormality.

2. The discrete acoustic tomography method for pile integrity detection according to claim 1, characterized in that, The acoustic wave sensor is deployed in the acoustic logging tube. A high-frequency, high-bandwidth acoustic wave transducer is selected, which includes an excitation source and a receiver. The excitation source and receiver are pre-embedded in the acoustic logging tube.

3. The discrete acoustic tomography method for pile integrity detection according to claim 1, characterized in that, The high-frequency ground-penetrating radar antenna and the acoustic sensor are deployed synchronously inside the acoustic tube. The antenna's operating frequency must penetrate the concrete and be sensitive to defects such as cavities and water-bearing cracks inside the pile.

4. The discrete acoustic tomography method for pile integrity detection according to claim 1, characterized in that, When installing the acoustic transducer using a lifting device, the operator cleans all the acoustic logging pipes and fills them with water, ensuring the water level is above the top of the pile.

5. The discrete acoustic tomography method for pile integrity detection according to claim 1, characterized in that, In step S2, after collecting data from 5-7 horizontal layers, the operator should randomly select 1-3 horizontal layers for a second, repeated measurement. The relative deviation between the arrival times of the first wave of the sound wave in the two measurements should be less than 2-3%.

6. The discrete acoustic tomography method for pile integrity detection according to claim 1, characterized in that, In step S3, cross-calibration must be performed using acoustic and electromagnetic wave sensors to ensure that the vertical depth error between the excitation position of the acoustic pulse and the scanning position of the electromagnetic wave does not exceed 0.1-0.3 cm.

7. The discrete acoustic tomography method for pile integrity detection according to claim 4, characterized in that, When the operators clean all the sonic logging pipes and fill them with water, they should check the water temperature inside the pipes every 3-5 hours.

8. The discrete acoustic tomography method for pile integrity detection according to claim 1, characterized in that, During continuous depth scanning by the ground-penetrating radar, the sensor should be lowered independently at a speed of 2-4 m / min.

9. The discrete acoustic tomography method for pile integrity detection according to claim 1, characterized in that, The cables used for sensor deployment must be low-noise, highly shielded data cables. During deployment, avoid tangling or twisting of the cables to prevent capacitive coupling noise.

10. The discrete acoustic tomography method for pile integrity detection according to claim 3, characterized in that, During the deployment process, the antenna must be kept stable and vertical to avoid shaking or tilting inside the tube and to maintain a uniform gap with the tube wall.