A pile body integrity detection method based on detection data

Abstract

The present invention proposes a pile body integrity detection method based on detection data, which belongs to the field of pile body structural defect detection, including: applying a stress wave with set stress conditions on the top of the pile body, and setting an ultrasonic receiver for monitoring the stress wave on the top of the pile body, calculating the position of the pile body defect from the top of the pile body through the reflected ultrasonic wave collected by the ultrasonic receiver, and locating the pile body defect area; according to the positioning of the pile body defect area, using an ultrasonic instrument and an ultrasonic receiver to perform ultrasonic detection on the pile body defects in the pile body defect area, and calculating the radial width of the pile body defect and the axial width of the pile body defect through the constructed wave equation. The pile body integrity detection method proposed by the present invention has the advantages of wide detection range, high resolution, and no damage to the pile body, and provides strong guarantee and data support for the safety and stability evaluation of pile foundation engineering.

Description

Technical Field

[0001] The invention relates to the field of pile body defect detection, and in particular to a pile body integrity detection method based on detection data. Background Art

[0002] In pile foundation engineering, the integrity of the pile body is directly related to the safety and stability of the overall project. Pile body defects generally include concrete segregation, mud inclusion, necking, poor density and broken piles. Traditional pile body detection methods include low strain method, acoustic wave transmission method, high strain method and core drilling method, but there are some obvious defects. The disadvantage of the acoustic wave transmission method is that the detected pile needs to be pre-buried with an acoustic detection tube, which increases the cost of the pile foundation. At the same time, the detection cost of the acoustic wave penetration method is relatively high. The core drilling method may not be very accurate in judging local defects and horizontal cracks in the pile foundation. It is generally combined with other detection methods. The detection cost is related to the pile length and the detection cost is also very high. At the same time, in actual use, generally only one method is used, resulting in problems such as limited detection range, low resolution, and possible damage to the pile body. Therefore, the present invention proposes a pile body integrity detection method based on detection data. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention provides a pile body integrity detection method based on detection data, which locates pile body defects and evaluates defect sizes based on a combination of stress wave detection and ultrasonic detection.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0005] A pile body integrity detection method based on detection data is provided, which comprises:

[0006] Step S1: Apply set stress to the top of the pile Stress wave conditions , and an ultrasonic receiver for monitoring stress waves is set at the top of the pile body, and the position of the pile body defect from the top of the pile body is calculated through the reflected ultrasonic waves collected by the ultrasonic receiver, and the defective area of ​​the pile body is located;

[0007] Step S2: Based on the location of the pile body defect area, ultrasonic detection is performed on the pile body defects in the pile body defect area using an ultrasonic instrument and an ultrasonic receiver, and the radial width of the pile body defect and the axial width of the pile body defect are calculated using the constructed wave equation.

[0008] Further, step S1 includes:

[0009] Step S11: Apply set stress to the top of the pile Stress wave conditions , and an ultrasonic receiver is set on the top of the pile to monitor the stress wave, and , is the minimum stress wave that can be sensed by the ultrasonic receiver. is the attenuation coefficient of stress wave in the length direction of the pile body, is the expansion coefficient, L is the length of the pile;

[0010] Step S12: establishing a damped wave equation of the stress wave according to the damping effect of the stress wave propagating in the length direction of the pile body;

[0011] Step S13: From the stress wave At the beginning of the application, the ultrasonic receiver receives the reflected stress wave, obtains the amplitude of the reflected stress wave, and records the reception time of the reflected stress wave. It is used as the propagation time of the stress wave on the pile body and input into the damped wave equation to calculate the position coordinates. x , that is, the distance between the pile body defect reflecting the stress wave and the top of the pile body;

[0012] Step S14: Repeat steps S11-S13 and apply n Secondary stress wave Afterwards, we get n Position coordinate data ,calculate n The average value of the position coordinate data , To apply the i Secondary stress wave The obtained position coordinates, i Stress wave The number of times applied;

[0013] Step S15: Filter out n Position coordinate data The minimum value in and maximum value , calculate the average With minimum ,average value With the maximum value The difference between , , and filter the difference , The maximum value between ;

[0014] Step S16: Obtain the pile body defect area on the pile body, and the position coordinate range of the pile body defect area is , the middle position of the pile defect area is located at the position coordinate Place.

[0015] Furthermore, the damped wave equation of the stress wave is:

[0016] ;

[0017] in, is the function of the amplitude of the stress wave changing with the propagation distance and time, x is the position coordinate along the length of the pile body starting from the top of the pile body, t is the propagation time of the stress wave, A 0 is stress wave The amplitude of is the damping coefficient, is the angular frequency of the stress wave, k is the wave number, is the phase difference, e is a natural constant.

[0018] Further, step S2 includes:

[0019] Step S21: Move the ultrasonic instrument to the position coordinates of the pile body At the ultrasonic receiver, the position coordinates to the opposite side of the ultrasonic instrument are At the point, the ultrasonic instrument generates ultrasonic waves and transmits them through the defective area of ​​the pile body to the ultrasonic receiver;

[0020] Step S22: Based on the initial sound pressure of the ultrasonic wave emitted by the ultrasonic instrument , calculate the ultrasonic sound pressure received by the ultrasonic receiver under ideal conditions ;

[0021] Step S23: Setting the sound pressure fluctuation threshold of the ultrasonic wave propagating within the cross-section of the pile body ;

[0022] ;

[0023] in, is the fluctuation coefficient caused by the unevenness of the pile material on ultrasonic propagation, is the error coefficient of the ultrasonic receiver;

[0024] Step S24: Establish the sound pressure fluctuation range of the ultrasonic signal propagating within the cross-sectional range of the pile body ; According to the ultrasonic signal received by the ultrasonic receiver, the sound pressure of the ultrasonic signal The range of sound pressure fluctuation Make comparisons;

[0025] like , then determine the time t The ultrasound signal is normal;

[0026] like , then determine the time t The ultrasonic signal is abnormal, delete the judgment time t Ultrasonic signal;

[0027] like , then determine the time t The ultrasonic signal is an attenuated ultrasonic signal, executing step S25;

[0028] Step S25: constructing a wave equation for the propagation of ultrasonic waves in the defective region of the pile body, where the ultrasonic waves propagate as cylindrical waves in the defective region of the pile body;

[0029] Step S26: Obtain the time corresponding to each attenuated ultrasonic signal t , input into the wave equation, calculate the radial propagation distance data corresponding to each attenuated ultrasonic signal , w is the number of radial propagation distances, For the w Radial propagation distance;

[0030] Step S27: Based on the radial propagation distance data Calculate the width of the pile defect reflected by each attenuated ultrasonic signal , get the pile body defect width data ;

[0031] Step S28: Filter out pile body defect width data The maximum value in and minimum value , the radial width of the pile defect in the pile defect area can be obtained , the axial width of the pile defect is .

[0032] Furthermore, the ultrasonic sound pressure The calculation method is:

[0033] ;

[0034] in, d is the diameter of the pile, are the attenuation constants of solid dielectric materials. f is the frequency of the ultrasonic wave, F is the anisotropy coefficient of the solid dielectric material, D is the grain diameter of the pile material. For concrete piles, the grain diameter is the average diameter of the aggregate.

[0035] Furthermore, the wave equation is:

[0036] ;

[0037] in, r is the polar coordinate distance of ultrasonic wave propagating radially in the pile body, c is the speed of ultrasonic wave, is the function of ultrasonic wave changing with space and time, is the polar coordinate angle.

[0038] The beneficial effects of the present invention are as follows: the present invention proposes a method for positioning and sizing pile body defects by comprehensively utilizing two detection technologies, thereby avoiding damage to the pile body structure itself, and at the same time, the operation is simple and the detection cost is low. Based on the processing and calculation of stress wave and ultrasonic wave waveform data, the pile body integrity is comprehensively, accurately and non-destructively detected. The pile body integrity detection method proposed by the present invention has the advantages of wide detection range, high resolution and no damage to the pile body, and provides strong guarantee and data support for the safety and stability evaluation of pile foundation engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The figure is a flow chart of the pile body integrity detection method based on detection data. DETAILED DESCRIPTION

[0040] The specific implementation modes of the present invention are described below to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0041] like Figure 1 As shown, a pile body integrity detection method based on detection data includes:

[0042] Step S1: Apply set stress to the top of the pile Stress wave conditions , and an ultrasonic receiver for monitoring stress waves is set at the top of the pile body, and the position of the pile body defect from the top of the pile body is calculated through the reflected ultrasonic waves collected by the ultrasonic receiver, and the defective area of ​​the pile body is located. Step S1 specifically includes:

[0043] Step S11: Apply set stress to the top of the pile Stress wave conditions , and an ultrasonic receiver is set on the top of the pile to monitor the stress wave, and , is the minimum stress wave that can be sensed by the ultrasonic receiver. is the attenuation coefficient of stress wave in the length direction of the pile body, is the expansion coefficient, which indicates the ratio at which the stress wave needs to be amplified.L is the length of the pile;

[0044] In this embodiment, the stress wave The amplitude is taken as the unit of the stress wave. During the propagation of the stress wave in the length direction of the pile, its intensity will gradually weaken, and the amplitude of the stress wave will also weaken as the propagation distance increases. Therefore, in order to ensure that the ultrasonic receiver can sense the clear reflected stress wave, it is necessary to ensure that the initial stress wave It must have sufficient strength, that is, the amplitude must be large enough.

[0045] Step S12: establishing a damped wave equation of the stress wave according to the damping effect of the stress wave propagating in the length direction of the pile body;

[0046] ;

[0047] in, is the function of the amplitude of the stress wave changing with the propagation distance and time, x is the position coordinate along the length of the pile body starting from the top of the pile body, t is the propagation time of the stress wave, A 0 is stress wave The amplitude of is the damping coefficient, is the angular frequency of the stress wave, k is the wave number, is the phase difference, e is a natural constant;

[0048] During the propagation of the stress wave in the length direction of the pile body, the stress wave will be reflected by the defects on the pile body, and the reflected stress wave will reach the ultrasonic receiver in advance. Therefore, the distance from the defect to the top of the pile body can be calculated by the transmission time of the reflected stress wave. In this embodiment, the damped wave equation ignores the slope of the stress wave propagating in the length direction of the pile body, which simplifies the complexity of the calculation.

[0049] Step S13: From the stress wave At the beginning of the application, the ultrasonic receiver receives the reflected stress wave, obtains the amplitude of the reflected stress wave, and records the reception time of the reflected stress wave. It is used as the propagation time of the stress wave on the pile body and input into the damped wave equation to calculate the position coordinates. x , that is, the distance between the pile body defect reflecting the stress wave and the top of the pile body;

[0050] Step S14: Repeat steps S11-S13 and apply n Secondary stress wave Afterwards, we get n Position coordinate data ,calculate nThe average value of the position coordinate data , To apply the i Secondary stress wave The obtained position coordinates, i Stress wave The number of times applied;

[0051] The reflected stress waves are all reflected back by the ultrasonic receiver from the upper part of the pile body defect, while the stress waves cannot reach the lower part of the pile body defect. Therefore, the present invention assumes that the pile body defect is symmetrical in shape up and down, thereby locating the pile body defect. The center of the upper part is first calculated, and then the range of the lower part is fitted through the symmetry effect.

[0052] Step S15: Filter out n Position coordinate data The minimum value in and maximum value , calculate the average With minimum ,average value With the maximum value The difference between , , and filter the difference , The maximum value between ;

[0053] Step S16: Obtain the pile body defect area on the pile body, and the position coordinate range of the pile body defect area is , the middle position of the pile defect area is located at the position coordinate Place.

[0054] Step S2: Based on the location of the pile body defect area, ultrasonic detection is performed on the pile body defects in the pile body defect area using an ultrasonic instrument and an ultrasonic receiver, and the radial width of the pile body defect and the axial width of the pile body defect are calculated by using the constructed wave equation. Step S2 specifically includes:

[0055] Step S21: Move the ultrasonic instrument to the position coordinates of the pile body At the ultrasonic receiver, the position coordinates to the opposite side of the ultrasonic instrument are At the point, the ultrasonic instrument generates ultrasonic waves and transmits them through the defective area of ​​the pile body to the ultrasonic receiver, and the ultrasonic receiver and the ultrasonic instrument are symmetrical along the axis of the pile body;

[0056] Step S22: Based on the initial sound pressure of the ultrasonic wave emitted by the ultrasonic instrument , calculate the ultrasonic sound pressure received by the ultrasonic receiver under ideal conditions ;

[0057] ;

[0058] in, d is the diameter of the pile, are the attenuation constants of solid dielectric materials. f is the frequency of the ultrasonic wave, F is the anisotropy coefficient of the solid dielectric material, D is the grain diameter of the pile material. For concrete piles, the grain diameter is the average diameter of the aggregate;

[0059] Step S23: Setting the sound pressure fluctuation threshold of the ultrasonic wave propagating within the cross-section of the pile body ;

[0060] ;

[0061] in, is the fluctuation coefficient caused by the unevenness of the pile material on ultrasonic propagation, is the error coefficient of the ultrasonic receiver, generally taken as ;

[0062] Step S24: Establish the sound pressure fluctuation range of the ultrasonic signal propagating within the cross-sectional range of the pile body ; According to the ultrasonic signal received by the ultrasonic receiver, the sound pressure of the ultrasonic signal The range of sound pressure fluctuation Make comparisons;

[0063] like , then determine the time t The ultrasound signal is normal;

[0064] like , then determine the time t The ultrasonic signal is abnormal, delete the judgment time t Ultrasonic signal;

[0065] like , then determine the time t The ultrasonic signal is an attenuated ultrasonic signal, executing step S25;

[0066] During the transmission of the ultrasonic signal inside the pile body, it will be greatly weakened by the pile body defects and change the transmission speed of the ultrasonic signal. The width of the pile body defect can be calculated by the difference in the speed of the ultrasonic signal propagating between the pile body material medium and the defective medium.

[0067] Step S25: constructing a wave equation for the propagation of ultrasonic waves in the defective region of the pile body, where the ultrasonic waves propagate as cylindrical waves in the defective region of the pile body;

[0068] ;

[0069] in, r is the polar coordinate distance of ultrasonic wave propagating radially in the pile body, c is the speed of ultrasonic wave, is the function of ultrasonic wave changing with space and time, is the polar coordinate angle;

[0070] Step S26: Obtain the time corresponding to each attenuated ultrasonic signal t , input into the wave equation, calculate the radial propagation distance data corresponding to each attenuated ultrasonic signal , w is the number of radial propagation distances, For the w Radial propagation distance;

[0071] Step S27: Based on the radial propagation distance data Calculate the width of the pile defect reflected by each attenuated ultrasonic signal , get the pile body defect width data ;

[0072] Step S28: Filter out pile body defect width data The maximum value in and minimum value , the radial width of the pile defect in the pile defect area can be obtained , the axial width of the pile defect is .

[0073] The present invention proposes a method for locating and evaluating the size of pile body defects by comprehensively utilizing two detection technologies, thereby avoiding damage to the pile body structure itself. At the same time, the method is simple to operate and has low detection cost. Based on the processing and calculation of stress wave and ultrasonic wave waveform data, the method realizes comprehensive, accurate, and non-destructive detection of pile body integrity. The pile body integrity detection method proposed by the present invention has the advantages of wide detection range, high resolution, and no damage to the pile body, and provides strong guarantee and data support for the safety and stability evaluation of pile foundation engineering.

Claims

1. A pile body integrity detection method based on detection data, characterized in that: include: Step S1: Apply set stress to the top of the pile Stress wave conditions , and an ultrasonic receiver for monitoring stress waves is set at the top of the pile body, and the position of the pile body defect from the top of the pile body is calculated through the reflected ultrasonic waves collected by the ultrasonic receiver, and the defective area of ​​the pile body is located; Step S2: according to the location of the pile body defect area, ultrasonic detection is performed on the pile body defects in the pile body defect area using an ultrasonic instrument and an ultrasonic receiver, and the radial width of the pile body defect and the axial width of the pile body defect are calculated by the constructed wave equation; The step S1 comprises: Step S11: Apply set stress to the top of the pile Stress wave conditions , and an ultrasonic receiver is set on the top of the pile to monitor the stress wave, and , is the minimum stress wave that can be sensed by the ultrasonic receiver. is the attenuation coefficient of stress wave in the length direction of the pile body, is the expansion coefficient, L is the length of the pile; Step S12: establishing a damped wave equation of the stress wave according to the damping effect of the stress wave propagating in the length direction of the pile body; Step S13: From the stress wave At the beginning of the application, the ultrasonic receiver receives the reflected stress wave, obtains the amplitude of the reflected stress wave, and records the reception time of the reflected stress wave. It is used as the propagation time of the stress wave on the pile body and input into the damped wave equation to calculate the position coordinates. x , that is, the distance between the pile body defect reflecting the stress wave and the top of the pile body; Step S14: Repeat steps S11-S13 and apply n Secondary stress wave Afterwards, we get n Position coordinate data ,calculate n The average value of the position coordinate data , To apply the i Secondary stress wave The obtained position coordinates, i Stress wave The number of times applied; Step S15: Filter out n Position coordinate data The minimum value in and maximum value , calculate the average With minimum ,average value With the maximum value The difference between , , and filter the difference , The maximum value between ; Step S16: Obtain the pile body defect area on the pile body, and the position coordinate range of the pile body defect area is , get the middle position of the defective area of ​​the pile body; The step S2 comprises: Step S21: the ultrasonic instrument is moved to the middle position of the defective area of ​​the pile body, and the ultrasonic receiver is moved to the middle position of the defective area on the opposite side of the ultrasonic instrument. The ultrasonic instrument generates ultrasonic waves and transmits them through the defective area of ​​the pile body to the ultrasonic receiver. Step S22: Based on the initial sound pressure of the ultrasonic wave emitted by the ultrasonic instrument , calculate the ultrasonic sound pressure received by the ultrasonic receiver under ideal conditions ; Step S23: Setting the sound pressure fluctuation threshold of the ultrasonic wave propagating within the cross-section of the pile body ; ； in, is the fluctuation coefficient caused by the unevenness of the pile material on ultrasonic propagation, is the error coefficient of the ultrasonic receiver; Step S24: Establish the sound pressure fluctuation range of the ultrasonic signal propagating within the cross-sectional range of the pile body ; According to the ultrasonic signal received by the ultrasonic receiver, the sound pressure of the ultrasonic signal The range of sound pressure fluctuation Make comparisons; like , then determine the time t The ultrasound signal is normal; like , then determine the time t The ultrasonic signal is abnormal, delete the judgment time t Ultrasonic signal; like , then determine the time t The ultrasonic signal is an attenuated ultrasonic signal, executing step S25; Step S25: constructing a wave equation for the propagation of ultrasonic waves in the defective region of the pile body, where the ultrasonic waves propagate as cylindrical waves in the defective region of the pile body; Step S26: Obtain the time corresponding to each attenuated ultrasonic signal t , input into the wave equation, calculate the radial propagation distance data corresponding to each attenuated ultrasonic signal , w is the number of radial propagation distances, For the w Radial propagation distance; Step S27: Based on the radial propagation distance data Calculate the width of the pile defect reflected by each attenuated ultrasonic signal , get the pile body defect width data , is the polar coordinate angle, d is the diameter of the pile; Step S28: Filter out pile body defect width data The maximum value in and minimum value , the radial width of the pile defect in the pile defect area can be obtained , the axial width of the pile defect is .

2. The pile body integrity detection method based on detection data according to claim 1 is characterized in that: The damped wave equation of the stress wave is: ； in, is the function of the amplitude of the stress wave changing with the propagation distance and time, x is the position coordinate along the length of the pile body starting from the top of the pile body, t is the propagation time of the stress wave, A 0 is stress wave The amplitude of is the damping coefficient, is the angular frequency of the stress wave, k is the wave number, is the phase difference, e is a natural constant.

3. The pile body integrity detection method based on detection data according to claim 1 is characterized in that: The ultrasonic sound pressure The calculation method is: ； in, are the attenuation constants of solid dielectric materials. f is the frequency of the ultrasonic wave, F is the anisotropy coefficient of the solid dielectric material, D is the grain diameter of the pile material. For concrete piles, the grain diameter is the average diameter of the aggregate.

4. The pile body integrity detection method based on detection data according to claim 1 is characterized in that: The wave equation of the ultrasonic wave propagating in the defect area of ​​the pile body is: ； in, r is the polar coordinate distance of ultrasonic wave propagating radially in the pile body, c is the speed of ultrasonic wave, U Right now , which is a function of the change of ultrasound with space and time.

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