Pile body defect three-dimensional accurate positioning method based on BIM and sound wave transmission method

Abstract

The invention provides a pile body defect three-dimensional accurate positioning method based on BIM and a sound wave transmission method, and the method comprises the steps: building a pile foundation structure model in a BIM platform, and distributing a unique number for each sounding pipe; in the on-site detection process, acoustic time, amplitude and dominant frequency data of each detection depth are collected by using an acoustic transmission method; and importing the detection data into the BIM system, and establishing a unique identifier according to the stake number, the sounding pipe number and the detection depth to realize the corresponding association of the acoustic parameters and the model nodes. According to the method, acoustic parameter data detected by a sound wave transmission method is deeply fused with a BIM model, a unique identifier is established by using a stake number, a sounding pipe number and a detection depth, automatic correspondence between detection data and a model component is realized, after detection is completed, a system calculates three-dimensional space coordinates of defects in a BIM coordinate system, and the defect detection accuracy is improved. And labeling is performed in the model in a visual manner, so that the position, form and range of the defect in a three-dimensional space are visually presented, and the intuition and accuracy of defect positioning are improved.

Description

Technical Field

[0001] This invention relates to the field of building engineering testing technology, and in particular to a method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method. Background Technology

[0002] Pile foundations are one of the most critical load-bearing units in a building structure's load-bearing system, and their quality directly affects the safety and stability of the superstructure. In order to evaluate the integrity of the pile body and the density of the concrete after construction, the acoustic transmission method (also known as ultrasonic testing) is often used in engineering to test the quality of the pile body.

[0003] The acoustic transmission method typically involves pre-embedding several acoustic logging tubes inside the pile body as detection channels before the pile foundation is poured. During detection, the transmitting transducer and the receiving transducer are placed in two parallel acoustic logging tubes and raised synchronously at the same speed. The transmitting transducer emits high-frequency ultrasonic pulse signals into the concrete, and the receiving transducer receives the transmitted signals in another acoustic logging tube. By analyzing the three main parameters of ultrasonic wave propagation in the concrete—sound time, amplitude, and dominant frequency—the density and integrity of the pile concrete can be determined.

[0004] 1. The output of the test is usually two-dimensional data such as waveform diagrams, acoustic time-depth curves, and amplitude-depth curves. These results are difficult to directly reflect the three-dimensional spatial morphology of the defect inside the pile body. They need to be analyzed and interpreted by experienced professionals. The technical threshold is high, and non-professionals cannot judge the true location and extent of the defect based on two-dimensional curves.

[0005] Second, in traditional testing, the transducer lifting process relies on manual operation. The lifting speed is greatly affected by human factors, which can easily lead to uneven speed, intermittent pauses, or even reverse slippage. This causes the sampling depth to be inconsistent with the actual detection depth. The depth error directly affects the vertical positioning accuracy of the defect, which is one of the technical bottlenecks of the existing acoustic transmission method. Currently, most testing instruments only draw curves based on the "lifting depth recorded by the operator" and lack real-time correction, resulting in a large deviation in the vertical position judgment of the defect and affecting the reliability of the test.

[0006] Third, acoustic wave test reports are usually presented as standalone documents and are not directly linked to design drawings or BIM models. Construction, design, and supervision personnel cannot visually view the location of defects in a three-dimensional environment, nor can they achieve a one-to-one correspondence between test results and the pile foundation structure, resulting in low efficiency in the formulation of subsequent pile repair, reinforcement, or pile head treatment plans.

[0007] To address this, a three-dimensional precise positioning method for pile defects based on BIM and acoustic transmission method is proposed. Summary of the Invention

[0008] In view of this, the present invention provides a three-dimensional precise positioning method for pile defects based on BIM and acoustic transmission method, so as to solve or alleviate the technical problems existing in the prior art, and at least provide a beneficial option.

[0009] The technical solution of this invention is implemented as follows: A method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method, comprising the following steps:

[0010] S1. Establish a structural model of the pile foundation to be tested in the BIM model, and pre-set a number of sonic logging tubes in the structural model, and assign a unique number to each sonic logging tube.

[0011] The BIM model includes the pile structure, the sonic logging pipe model, and the concrete material information layer. The number, location coordinates, and corresponding pile number of each sonic logging pipe are stored in the BIM dataset to achieve one-to-one matching between the detection data and the model components.

[0012] S2. During the on-site testing process, the transmitting transducer and the receiving transducer are respectively placed into two parallel acoustic tubes and raised at the same speed to collect the acoustic time, amplitude and main frequency data of the pile body at each testing depth.

[0013] S3. Establish the data association between acoustic parameter data and BIM model, match the acoustic parameters collected on site with the pile number and sonic logging pipe number in BIM model, and perform depth alignment to eliminate depth error caused by manual inspection.

[0014] The data association is established through a unique identifier, which is composed of the station number, the sonic logging tube number, and the detection depth. When importing data, the detection software automatically matches the acoustic parameter data with the corresponding objects in the BIM model based on this identifier.

[0015] The depth alignment process includes:

[0016] The actual detection depth of each sampling point is calculated by using the real-time lifting speed signal and sampling time series of the detection equipment. After the detection data is imported into the BIM model, the system automatically matches the depth information of the data with the depth node of the sonic logging pipe in the BIM model to form a vertical correspondence between the detection profile and the model components.

[0017] S4. Based on the preset defect criteria, analyze the acoustic parameters of each detection profile, identify abnormal detection points, and record the corresponding detection depth.

[0018] The defect criterion is established as follows:

[0019] Using the acoustic parameters of the complete concrete section as the reference range, when the acoustic time phase of the detection point increases by more than the set threshold, the amplitude decreases by more than the set threshold, or the main frequency decreases by more than the set threshold compared to the reference section parameters, the system automatically determines that the point is a potential anomaly point, thereby determining whether there are mud inclusions, voids, or structural defects of non-dense concrete inside the pile body.

[0020] S5. Based on the spatial arrangement of the inspection profile and the sonic logging pipes, use the geometric positioning algorithm to calculate the three-dimensional spatial coordinates of the defect points in the BIM model coordinate system.

[0021] The geometric positioning algorithm includes: determining the precise two-dimensional coordinates of the defect point in the detection profile plane by performing interpolation calculations along the direction of the line connecting the two acoustic tubes, based on the spatial coordinates of the acoustic tubes on both sides of the detection profile where the defect point is located, and the acoustic time change or amplitude attenuation ratio of the defect point.

[0022] S6. The calculated defect coordinates and attribute information are displayed in a three-dimensional visualization in the BIM model, and a pile foundation inspection report containing defect coordinates and related acoustic parameter information is automatically generated.

[0023] The visualization methods for defects in the BIM model include:

[0024] In the model interface, defect point markers are generated at the corresponding pile positions, and abnormal changes in detection depth, acoustic time, amplitude, and dominant frequency are marked near the defect points.

[0025] More preferably, the pile foundation inspection report is automatically generated by the system based on acoustic parameter data and defect coordinate information. The report includes a list of inspection profiles for each pile number, the corresponding acoustic parameter curves, a table of identified defect points, and a screenshot of the three-dimensional model. The report also automatically includes the three-dimensional coordinates of the defect points and the corresponding inspection depth information.

[0026] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions:

[0027] I. This invention deeply integrates acoustic parameter data obtained by acoustic wave transmission method with BIM model, and establishes a unique identifier using pile number, acoustic pipe number and detection depth to realize automatic correspondence between detection data and model components. After detection, the system calculates the three-dimensional spatial coordinates of the defect in BIM coordinate system and marks it in the model in a visual way, so that the position, shape and range of the defect in three-dimensional space are presented intuitively, improving the intuitiveness and accuracy of defect location.

[0028] Second, this invention achieves automatic alignment of the detection depth by recording the transducer's lifting speed signal in real time and integrating and interpolating the detection depth using the sampling time series. This effectively eliminates the depth deviation caused by the instability of manual lifting speed, making the judgment of the vertical position of defects no longer dependent on manual operation experience, thus ensuring high accuracy in the vertical positioning of defects. At the same time, the corrected detection depth data is written into the BIM database in the form of standardized nodes, which can be traced and compared throughout the entire process in subsequent inspection verification, construction quality tracking, and operation and maintenance management, thereby improving the credibility, usability, and life cycle value of the detection data.

[0029] Third, this invention achieves visual integration of defect information and pile foundation structure through BIM model. Design, supervision and construction personnel can intuitively view the location and severity of defects in the three-dimensional model, providing accurate basis for pile foundation reinforcement, pile supplementation or structural review, and improving decision-making efficiency.

[0030] Fourth, this invention uses a lateral interpolation mechanism based on acoustic time difference, amplitude attenuation, or dominant frequency variation to make the lateral positioning of defects no longer limited to the simple estimation of the "midpoint of the connection line of acoustic logging pipes". Instead, it uses the propagation characteristics of sound waves in concrete to determine which side of the acoustic logging pipe the defect is biased towards, thus achieving a higher accuracy in lateral position estimation. For piles with three or four acoustic logging pipes, this invention uses multi-section spatial intersection or weighted fusion to find the optimal position of the defect point, improving the stability and noise resistance of the positioning calculation, thereby improving the accuracy of three-dimensional defect identification.

[0031] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of the three-dimensional precise positioning method for pile defects based on BIM and acoustic transmission method according to the present invention. Detailed Implementation

[0034] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] like Figure 1 As shown, this embodiment of the invention provides a method for precise three-dimensional localization of pile defects based on BIM and acoustic transmission method. This method combines Building Information Modeling (BIM) data management with acoustic transmission detection technology. Through the analysis and spatial mapping of acoustic parameters, it achieves automatic identification and three-dimensional localization of internal pile defects, including the following steps:

[0037] S1. Establish BIM pile foundation model

[0038] Before the inspection, a three-dimensional information model of the pile foundation to be inspected is established in the BIM platform. The BIM model is established based on the pile foundation construction drawings, including the pile geometry, reinforcement cage, concrete volume information and sonic logging pipe structure model. The number and distribution of sonic logging pipes are determined according to the construction requirements. 3 to 4 sonic logging pipes are evenly distributed around the outside of the pile body, and each sonic logging pipe runs from the bottom of the pile to the top of the pile.

[0039] During the modeling process, a unique number (such as P1, P2, P3, P4) is automatically generated for each sonic logging pipe, and its spatial coordinate information (X, Y, Z) is recorded to ensure that the detection data can correspond to the BIM object. The above coordinates are calculated from the relative angle between the center point of the pile and the sonic logging pipe, forming the spatial geometric layout data under the model coordinate system.

[0040] The above information is stored in the sonic logging pipe table in the BIM database. Each record includes fields for station number, sonic logging pipe number, coordinate value, depth range, pipe diameter, and material properties.

[0041] Examples are as follows (Table 1):

[0042] Table 1 Information on Sonic Logging Pipes

[0043] Pipe number Station number X coordinate Y coordinate Depth range Pipe diameter Material P1 ZK-1 1.20 0.80 0～30 50 PVC P2 ZK-1 -1.20 0.80 0～30 50 PVC P3 ZK-1 -1.20 -0.80 0～30 50 PVC P4 ZK-1 1.20 -0.80 0～30 50 PVC

[0044] The spatial information of this model provides geometric support for the mapping between subsequent detection data and BIM objects.

[0045] S2. Acquire acoustic wave transmission data

[0046] The acoustic wave transmission test is completed using an ultrasonic testing instrument. Before the test, each acoustic tube is filled with clean water as a coupling medium to ensure that the acoustic waves can be smoothly transmitted into the concrete. During the test, the transmitting transducer and the receiving transducer are placed in two parallel acoustic tubes and kept at the same height. The testing instrument synchronously controls the two transducers to be lifted from the bottom of the pile to the top of the pile at a constant speed (0.5~1.0m / s).

[0047] The transmitting transducer periodically emits high-frequency ultrasonic pulse signals in the range of 20–50 kHz, and the receiving transducer receives the waveform signals after penetrating the concrete of the pile. The system automatically samples and calculates the following acoustic parameters:

[0048] Acoustic time (T): The time interval between the transmission and reception of a sound wave, measured in μs;

[0049] Amplitude (A): The maximum amplitude of the first wave of the received signal, in dB;

[0050] Main frequency (f): The main peak frequency in the received signal spectrum, in kHz.

[0051] Data was collected at 0.2 m intervals. For example, for the sonic logging tube pair P1–P2 at station ZK-1, the following is an example of the detection data:

[0052] Table 2 Acoustic wave detection data

[0053] Station number Sonic logging pipe pair Depth (m) Acoustic duration (μs) Amplitude (dB) Clock speed (kHz) ZK-1 P1–P2 5.0 102 -3.5 30 ZK-1 P1–P2 10.0 118 -6.1 25 ZK-1 P1–P2 15.0 149 -10.4 20

[0054] After the data collection is completed, the detector generates a data file, in which each record contains the station number, sonic logging tube pair number, detection depth, sound time, amplitude, dominant frequency and sampling timestamp;

[0055] S3, Data Association and Depth Alignment

[0056] This step achieves a precise correspondence between the inspection data and the BIM model, including:

[0057] (1) Data import and relationship establishment

[0058] After the inspection is completed, the collected acoustic data file is imported into the BIM data management module. The system automatically parses the file structure, extracts key fields such as station number (e.g., ZK-1), acoustic tube pair number (P1–P2), and inspection depth (10.0 m), and establishes a unique identifier:

[0059] The unique identifier ID = station number + sonic logging tube pair number + detection depth (e.g., ZK1_P1P2_10.0)

[0060] The BIM database contains a corresponding spatial node table (Node_Table) that records the geometric coordinates of each depth location. By matching unique identifiers, the acoustic parameters in the detection data are bound one-to-one with the BIM model nodes. The mapping relationship is as follows (Table 3):

[0061] Table 3 Data-Node Mapping Relationship

[0062] Data ID Acoustic duration (μs) Amplitude (dB) Clock speed (kHz) Depth (m) Corresponding node coordinates (X, Y, Z) ZK1_P1P2_10.0 118 -6.1 25 10.0 (1.20， 0.80， -10.0) ZK1_P1P2_15.0 149 -10.4 20 15.0 (1.20， 0.80， -15.0)

[0063] The acoustic parameters at each detection point have precise three-dimensional coordinate attributes, achieving deep integration of data and space.

[0064] (2) Depth error correction and interpolation alignment

[0065] During manual operation, the transducer lifting speed may vary slightly, causing a small deviation (typically ±0.1 m) between the actual depth of the sampling point and the theoretical depth. To eliminate this error, the system calculates the actual detection depth based on the real-time velocity curve v(t) recorded by the transducer velocity sensor.

[0066]

[0067] Then, the values ​​are compared with the theoretical depth value. When the deviation exceeds the set threshold, a linear interpolation algorithm is used to correct the acoustic parameter values ​​of adjacent sampling points.

[0068] For example, when the actual depth of the 10.0 m sampling point is 9.92 m, the system interpolates and compensates based on the 9.8 m and 10.2 m sampling data to generate corrected standardized data, so that the profile data are strictly aligned in the vertical direction.

[0069] After the correction is completed, the system automatically updates the detection data table (Data_Table) to ensure that all acoustic parameters are spatially consistent with the BIM model coordinates.

[0070] S4. Defect Judgment

[0071] After data alignment is completed, the system automatically identifies outliers based on the trend of acoustic parameter changes. Taking the complete 0-5m section of the upper part of the pile as the reference interval, the system calculates the average value and standard deviation of its acoustic parameters and uses them as the comparison benchmark.

[0072] When the increase in acoustic time at a detection point exceeds 20%, the amplitude attenuation exceeds 50%, and the main frequency decreases by more than 30%, the system determines that the point is a potential defect point.

[0073] For example, at a depth of 15.0 m, the acoustic time was measured to be 149 μs, the amplitude was -10.4 dB, and the dominant frequency was 20 kHz, which was significantly abnormal compared to the reference section. The system automatically marked this point as a potential defect.

[0074] The parameter information for all defects is written into the Defect_Table, in the following format (Table 4):

[0075] Table 4 Defect Records

[0076] Defect number Station number Sonic logging pipe pair Depth (m) Acoustic duration (μs) Amplitude (dB) Clock speed (kHz) D001 ZK-1 P1–P2 15.0 149 -10.4 20

[0077] S5, Defect Spatial Location

[0078] During the defect location process, the system not only locates the defect based on the geometric relationship between the acoustic tubes, but also combines the physical characteristics of the acoustic transmission method and uses acoustic indicators such as acoustic time difference, amplitude attenuation ratio or main frequency drop to perform more accurate lateral interpolation calculations to determine the precise location of the defect point in the detection profile.

[0079] Specifically, when a detection profile consists of two acoustic logging tubes, the system first reads the spatial coordinates of the two tubes at the detection depth and establishes a connecting vector in the depth plane. Then, based on the difference in acoustic time or amplitude parameters at the abnormal detection points at that depth, the system calculates the interpolation ratio of the defect point on the connecting vector. For example, when the defect is closer to the transmitting transducer, its acoustic time is usually shorter and its amplitude attenuation is more significant; the system can perform linear interpolation according to the following formula:

[0080] in:

[0081] The amplitude values ​​corresponding to the positions of the two acoustic tubes; The time variation of sound from the two acoustic tubes; The weight coefficient of the defect point on the connecting vector.

[0082] Therefore, the lateral coordinate of the defect point can be expressed as:

[0083]

[0084] When three or four sonic logging tubes are arranged on the pile body, the system uses the interpolation results of multiple profiles as independent observation points, and obtains the optimal location of the defect point through the weighted average method or the least squares method, so as to improve the stability and noise resistance of the positioning.

[0085] This step enables refined defect localization based on differences in acoustic parameters, avoiding the accuracy deviation caused by "fixed midpoint" localization.

[0086] S6. Defect Visualization and Detection Report Generation

[0087] The system automatically generates defect markers in the BIM model interface, displaying a red spherical marker at the Z=-15.0 m position, indicating the defect number, detection depth, and main acoustic parameter values;

[0088] Operators can use the model view rotation function to view the spatial location and distribution of defects in the pile body, call up acoustic parameter data from the detection database, and automatically generate a detection report based on a preset template.

[0089] The workflow of this invention is as follows:

[0090] Before the inspection, a three-dimensional information model of the pile foundation to be inspected is established on the BIM platform, including the pile body structure, concrete information layer and sonic logging tube model. The system assigns a unique number to each sonic logging tube and records its coordinate information, and generates a pile number and sonic logging tube attribute table to provide a geometric basis for subsequent data matching.

[0091] The detection was carried out using the acoustic transmission method. The transmitting and receiving transducers were placed in two parallel acoustic tubes and raised synchronously at a constant speed to collect acoustic time, amplitude and main frequency data at each detection depth.

[0092] After the test is completed, the instrument generates a raw data file containing the station number, sonic logging tube number, and depth information.

[0093] The detection data is imported into the BIM data management module. The system establishes a unique identifier based on the pile number, sonic logging pipe number, and depth to achieve a one-to-one correspondence between acoustic parameters and BIM model nodes. If there is a deviation in the detection depth, the system automatically calculates the actual depth based on the transducer lifting speed signal and performs interpolation correction to complete the standardization and vertical alignment of the data.

[0094] Using the complete upper section of the pile as a reference, the system automatically compares the acoustic parameters of each measuring point. When the increase in acoustic time, the attenuation of amplitude, or the decrease in dominant frequency exceeds the set threshold, the point is determined to be a potential defect, and the corresponding depth and parameter values ​​are recorded. Based on the spatial coordinates of the acoustic logging tube and the depth of the defect point, the system uses a geometric positioning algorithm to calculate the three-dimensional position of the defect in the BIM model coordinate system and generates a defect coordinate data table to achieve the fusion of the detection results and the model space.

[0095] The system automatically generates defect point markers in the BIM model and labels the inspection depth and key parameters. Simultaneously, it generates an inspection report based on a preset template. The report includes acoustic parameter curves, a defect point table, and screenshots of the 3D model, and is output as a PDF file for archiving.

[0096] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method, characterized in that, Includes the following steps: S1. Establish a structural model of the pile foundation to be tested in the BIM model, and pre-set a number of sonic logging tubes in the structural model, and assign a unique number to each sonic logging tube. S2. During the on-site testing process, the transmitting transducer and the receiving transducer are respectively placed into two parallel acoustic tubes and raised at the same speed to collect the acoustic time, amplitude and main frequency data of the pile body at each testing depth. S3. Establish the data association between acoustic parameter data and BIM model, match the acoustic parameters collected on site with the pile number and sonic logging pipe number in BIM model, and perform depth alignment to eliminate depth error caused by manual inspection. S4. Based on the preset defect criteria, analyze the acoustic parameters of each detection profile, identify abnormal detection points, and record the corresponding detection depth. S5. Based on the spatial arrangement of the inspection profile and the sonic logging pipes, use the geometric positioning algorithm to calculate the three-dimensional spatial coordinates of the defect points in the BIM model coordinate system. S6. The calculated defect coordinates and attribute information are displayed in a three-dimensional visualization in the BIM model, and a pile foundation inspection report containing defect coordinates and related acoustic parameter information is automatically generated.

2. The method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method according to claim 1, characterized in that: The BIM model includes the pile structure, the sonic logging pipe model, and the concrete material information layer. The number, location coordinates, and corresponding pile number of each sonic logging pipe are stored in the BIM dataset to achieve one-to-one matching between the detection data and the model components.

3. The method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method according to claim 1, characterized in that: The depth alignment process includes: The actual detection depth of each sampling point is calculated by using the real-time lifting speed signal and sampling time series of the detection equipment. After the detection data is imported into the BIM model, the system automatically matches the depth information of the data with the depth node of the sonic logging pipe in the BIM model to form a vertical correspondence between the detection profile and the model components.

4. The method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method according to claim 1, characterized in that: The defect criterion is established as follows: Using the acoustic parameters of the complete concrete section as the reference range, when the acoustic time phase of the detection point increases by more than the set threshold, the amplitude decreases by more than the set threshold, or the main frequency decreases by more than the set threshold compared to the reference section parameters, the system automatically determines that the point is a potential anomaly point, thereby determining whether there are mud inclusions, voids, or structural defects of non-dense concrete inside the pile body.

5. The method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method according to claim 1, characterized in that: The geometric positioning algorithm includes: Based on the spatial coordinates of the acoustic logging tubes on both sides of the detection profile where the defect point is located, and the acoustic time change or amplitude attenuation ratio of the defect point, the precise two-dimensional coordinates of the defect point in the detection profile plane are determined by performing interpolation calculations along the direction of the line connecting the two acoustic logging tubes.

6. The method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method according to claim 1, characterized in that: The data association is established through a unique identifier, which is composed of the station number, the sonic logging tube number, and the detection depth. When importing data, the detection software automatically matches the acoustic parameter data with the corresponding objects in the BIM model based on this identifier.

7. The method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method according to claim 1, characterized in that: The visualization methods for defects in the BIM model include: In the model interface, defect point markers are generated at the corresponding pile positions, and abnormal changes in detection depth, acoustic time, amplitude, and dominant frequency are marked near the defect points.

8. The method for precise three-dimensional positioning of pile defects based on BIM and acoustic transmission method according to claim 1, characterized in that: The pile foundation inspection report is automatically generated by the system based on acoustic parameter data and defect coordinate information. The report includes a list of inspection profiles for each pile number, the corresponding acoustic parameter curves, a table of identified defect points, and a 3D model screenshot. The 3D coordinates and corresponding inspection depth information of the defect points are automatically attached to the report.

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