Bridge pier foundation scouring ultrasonic detection method using wall-climbing robot

Abstract

The application discloses a kind of bridge pier foundation scouring ultrasonic detection methods using wall-climbing robot, belong to bridge detection technical field, comprising the following steps: S10, select appropriate steel pipe, corresponding detection equipment is transported to the area to be measured with steel pipe;S20, steel pipe is sunk into the river bed below the area to be measured, and wall-climbing robot is placed to the inside of steel pipe;S30, wall-climbing robot is lowered to the first vertical measurement interval with ultrasonic detection equipment, and wall-climbing robot is fixed to the height;S40, ultrasonic probe is placed on the inner wall of steel pipe, and external water area signal is collected, after collection, ultrasonic probe is withdrawn;S50, wall-climbing robot is slid down to the next vertical measurement interval;S60, after data acquisition is completed, detection equipment is withdrawn, and the ultrasonic echo data collected is processed to identify the scouring boundary and scouring depth around bridge pier foundation.The application effectively reduces the interference of wave flow, and improves detection accuracy.

Description

Technical Field

[0001] This invention belongs to the field of bridge inspection technology, and more specifically relates to an ultrasonic inspection method for bridge pier foundation scour using a wall-climbing robot. Background Technology

[0002] Under the impact of water flow, bridge pier foundations are subjected to varying degrees of scouring, which reduces the foundation's bearing capacity and, in severe cases, may lead to bridge structural instability. Existing methods for detecting bridge foundation scouring mainly include shipborne sonar detection, diver detection, and underwater robot detection. However, in complex water environments such as deep water, rapid currents, and high turbidity, these methods generally suffer from insufficient detection stability, high operational risks, and limited accuracy in identifying scouring boundaries.

[0003] To improve the operational stability of testing equipment, a testing channel can be constructed using steel pipes, allowing the equipment to complete data acquisition in a relatively enclosed environment. However, when ultrasound propagates inside a steel pipe, it is prone to reflection from the pipe wall, multipath propagation, and echo superposition. Furthermore, it is affected by water flow disturbances and sediment scattering noise, causing the target echo and interfering echoes to couple, resulting in a significant non-stationary characteristic of the ultrasonic echo signal. This increases the difficulty of extracting target echo information and identifying scour boundaries. Existing ultrasonic signal processing methods are mainly designed for free propagation environments and have limited ability to process complex reflected echo signals in steel pipe environments, making it difficult to effectively extract feature information reflecting changes in scour boundaries.

[0004] Therefore, there is an urgent need for a detection method that can reliably identify the scour boundary and scour depth of bridge pier foundations within a steel pipe inspection channel. Summary of the Invention

[0005] To address the problem of difficulty in identifying scour boundaries and scour depths caused by ultrasonic echo signals being easily reflected from the steel pipe wall, propagating through multiple paths, and being interfered with by environmental noise in steel pipe confinement environments, this invention adopts the following technical solution: An ultrasonic testing method for scour of bridge pier foundations using a wall-climbing robot includes the following steps: S10. Select a steel pipe of appropriate height and diameter based on the hydrological data of the area to be tested and the testing equipment, and transport the corresponding testing equipment and steel pipe to the area to be tested. S20. Submerge the steel pipe below the riverbed of the area to be tested, and place the wall-climbing robot equipped with ultrasonic testing equipment at the top inside the steel pipe. S30. Select an appropriate vertical measurement interval based on the height of the bridge pier foundation in the measured area, lower the wall-climbing robot equipped with ultrasonic testing equipment to the first vertical measurement interval, and fix the wall-climbing robot at that height; S40. Place the ultrasonic probe of the ultrasonic testing equipment against the inner wall of the steel pipe, turn on the control center of the ultrasonic testing equipment, and use the ultrasonic probe to collect the ultrasonic echo signal of the scour area around the bridge pier foundation. After the collection is completed, retract the ultrasonic probe. S50. Release the locking device of the wall-climbing robot, slide the wall-climbing robot down to the next vertical measurement interval, and repeat steps S30 and S40. S60. After data acquisition is completed, the detection equipment is retrieved, and the acquired ultrasonic echo data is processed using ultrasonic echo signal processing methods to identify the scour boundary and scour depth around the bridge pier foundation.

[0006] Further, in step S50, the wall-climbing robot slides down to the next vertical measurement interval, steps S30 and S40 are repeated, and it is determined whether the wall-climbing robot has reached the bottom surface of the steel pipe. If it touches the bottom, the wall-climbing robot slides up and the detection device is retracted; if the wall-climbing robot has not reached the bottom of the steel pipe, steps S30 and S40 are repeated.

[0007] Furthermore, the ultrasonic testing equipment includes: a telescopic rod, an ultrasonic probe, and an ultrasonic equipment central system; the wall-climbing robot includes: a robot central control system, a robot sliding and adsorption device, and a robot support frame, one end of which is connected to the robot central control system, and the other end of which is connected to the robot sliding and adsorption device; The central system of the ultrasound equipment is mounted on the central control system of the robot. One end of the telescopic rod is connected to the central system of the ultrasound equipment, and the other end is connected to the ultrasound probe.

[0008] Furthermore, the telescopic rod has a horizontal rotation function to enable the ultrasonic probe to move circumferentially along the inner wall of the steel pipe to collect signals, and there are no fewer than three ultrasonic probes to meet the requirements of rapid acquisition.

[0009] Furthermore, during the sliding process of the wall-climbing robot, the telescopic rod of the ultrasonic testing equipment remains in a retracted state to ensure that the ultrasonic probe does not come into contact with the inner wall of the steel pipe.

[0010] Furthermore, in step S30, the vertical height at the first vertical measurement interval should be less than the water surface height.

[0011] Furthermore, in step S30, the vertical measurement spacing is selected according to the testing requirements and there is no fixed spacing, as long as the actual testing needs are met.

[0012] Furthermore, the ultrasonic echo signal processing method includes preprocessing the original ultrasonic echo signal; obtaining multiple IMF components using EEMD mode decomposition; selecting effective IMF components based on the correlation coefficient, energy ratio, and kurtosis index between each IMF component and the original signal; performing wavelet threshold noise reduction on the effective IMF components and reconstructing the signal; and extracting spectral feature parameters using FFT.

[0013] Furthermore, the spectral characteristics include one or more of the following: dominant frequency, band energy, echo delay, and amplitude attenuation.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides an ultrasonic testing method for bridge pier foundation scour using a wall-climbing robot. The wall-climbing robot carrying the ultrasonic testing equipment is located inside a steel pipe, which can effectively reduce the impact of wave and current disturbances on the stability of the testing equipment in complex water environments, improve the stability and reliability of the testing, and at the same time, the steel pipe can provide stable guidance and support for the wall-climbing robot to slide up and down.

[0015] 2. This detection method has strong environmental adaptability and can be widely used in still water, fast-flowing water, and turbid water environments; using robots for underwater detection operations can reduce the risks of manual underwater detection operations.

[0016] 3. The presence of steel pipes provides a long-term detection channel for scour detection of bridge pier foundations, thus enabling continuous monitoring of scour of bridge pier foundations using this method.

[0017] 4. In addition to detecting scour of bridge pier foundations, this method can also be applied to similar scenarios such as riverbed scour monitoring.

[0018] 5. The ultrasonic acquisition equipment and wall-climbing robot have automated acquisition capabilities, reducing manual operation and improving acquisition efficiency.

[0019] 6. This invention addresses the problems of multiple reflections, environmental noise interference, and non-stationary characteristics in ultrasonic echo signals under steel pipe confinement environments. It constructs an ultrasonic echo signal processing flow that combines empirical mode decomposition, effective IMF component screening, wavelet threshold denoising, and FFT spectrum analysis. This achieves effective separation of target echo information and interference information, and improves the signal-to-noise ratio and spectral feature extraction accuracy of ultrasonic echo signals.

[0020] 7. This invention constructs an ultrasonic echo signal processing flow adapted to the steel pipe constraint environment, enabling effective differentiation between target echo information and reflection interference information in the steel pipe environment. The steel pipe detection channel and the ultrasonic echo signal processing flow work together to improve the operational stability of the detection equipment while enhancing the reliability of identifying the scour boundary and scour depth of the bridge pier foundation. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a bridge foundation scour detection method based on ultrasonic testing technology provided by the present invention. Figure 2 A top view of the wall-climbing robot equipped with ultrasonic testing equipment provided by the present invention on the inner wall of a steel pipe; Figure 3 This is a schematic diagram of scour detection near bridge pier foundations provided by the present invention; Figure 4 This is a flowchart of the ultrasonic echo signal processing provided by the present invention.

[0023] The components include: 1. Water surface; 2. Wall-climbing robot; 3. Steel pipe; 4. Riverbed; 5. Bridge pier; 6. Scour pit; 7. Ultrasonic probe; 8. Telescopic support frame; 9. Central system of ultrasonic equipment; 10. Robot sliding and adsorption device; 11. Robot support frame; 12. Robot central control system. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] refer to Figure 1 - Figure 4 An ultrasonic testing method for scour of bridge pier foundations using a wall-climbing robot includes the following steps: S10. Determine the bridge foundation to be inspected, select a steel pipe 3 of appropriate height and diameter based on the hydrological data of the area to be tested and the testing equipment, and transport the corresponding testing equipment and steel pipe 3 to the area to be tested.

[0027] S20. Submerge one end of the steel pipe 3 into the riverbed 4 near the foundation of the bridge pier to be inspected to ensure that the steel pipe 3 remains stable during the inspection. Place the other end above the water surface 1 and place the wall-climbing robot 2 equipped with ultrasonic testing equipment inside the top of the steel pipe 3.

[0028] In this embodiment, an adhesive wall-climbing robot 2 equipped with an ultrasonic testing device is adsorbed onto the top of the inner wall of the steel pipe 3. After the wall-climbing robot 2 slowly slides down the inside of the steel pipe 3 to a fixed height, the adsorption device of the wall-climbing robot 2 fixes the wall-climbing robot 2 to the inner wall of the steel pipe 3. The ultrasonic testing probe mounted on the wall-climbing robot 2 extends out and abuts against the inner wall of the steel pipe 3.

[0029] Specifically, the ultrasonic testing equipment includes: a telescopic rod 8, an ultrasonic probe 7, and an ultrasonic equipment central system 9; the wall-climbing robot 2 includes: a robot central control system 12, a robot sliding and adsorption device 10, and a robot support frame 11, one end of which is connected to the robot central control system 12, and the other end is connected to the robot sliding and adsorption device 10. The ultrasonic equipment central system 9 is set on the robot central control system 12. One end of the telescopic rod 8 is connected to the ultrasonic equipment central system 9, and the other end is connected to the ultrasonic probe 7. In the initial state, the telescopic rod 8 can be staggered with the robot support frame 11.

[0030] In this embodiment, the telescopic rod 8 has a horizontal rotation function to achieve the purpose of moving the ultrasonic probe 7 circumferentially along the inner wall of the steel pipe 3 to collect signals, and there are no less than 3 ultrasonic probes 7 to meet the needs of rapid acquisition.

[0031] The telescopic rod 8 of the ultrasonic testing equipment extends until the ultrasonic probe 7 contacts the inside of the steel pipe 3 and stops. The control center of the ultrasonic testing equipment is activated, and the ultrasonic probe 7 is used to collect signals from the external water area. After the collection is completed, the ultrasonic probe 7 is retracted, and the telescopic rod 8 of the ultrasonic testing equipment is put into the retracted state.

[0032] The robot 2 uses a self-locking device to fix the robot at this height. It is worth noting that during the sliding process of the wall-climbing robot 2, the telescopic rod 8 of the ultrasonic testing equipment remains in a telescopic state to ensure that the ultrasonic probe 7 and the inner wall of the steel pipe 3 do not come into contact.

[0033] S30. Select an appropriate vertical measurement interval based on the height of the bridge pier foundation in the measured area, lower the wall-climbing robot 2 equipped with ultrasonic testing equipment to the first vertical measurement interval, and fix the wall-climbing robot 2 at that height.

[0034] Specifically, the vertical height at the first vertical measurement interval should be less than the water surface height.

[0035] The vertical measurement spacing is selected based on the testing requirements and there is no fixed spacing; it is sufficient to meet the actual testing needs.

[0036] More specifically, select an appropriate vertical measurement spacing based on the height h of the bridge pier foundation in the measured area. t 1. Lower the wall-climbing robot 2, equipped with ultrasonic testing equipment, to the first vertical height.h 1. Note the vertical height. h 1 should be less than the height of the water surface.

[0037] S40. Place the ultrasonic probe 7 of the ultrasonic testing equipment against the inner wall of the steel pipe 3, turn on the control center of the ultrasonic testing equipment, and use the ultrasonic probe 7 to collect the ultrasonic echo signal of the scour area around the bridge pier foundation. After the collection is completed, retract the ultrasonic probe 7.

[0038] S50. Release the locking device of the wall-climbing robot 2, so that the wall-climbing robot 2 is in a sliding state. Slide the wall-climbing robot 2 down to the next vertical measurement interval. Repeat steps S30 and S40 until the wall-climbing robot 2 slides down to the bottom of the steel pipe 3 and completes the last data acquisition.

[0039] Specifically, the wall-climbing robot 2 is slid down to the next vertical measurement interval, and steps S30 and S40 are repeated. It is determined whether the wall-climbing robot 2 has reached the bottom surface of the steel pipe 3. If it touches the bottom, the wall-climbing robot 2 is slid up and the detection device is retracted. If the wall-climbing robot 2 has not reached the bottom of the steel pipe 3, steps S30 and S40 are repeated.

[0040] More specifically, the self-locking device of the wall-climbing robot 2 is used to fix the robot at this height, and the telescopic rod 8 of the ultrasonic testing equipment is extended until the ultrasonic probe 7 touches the inner wall of the steel pipe 3 and stops. The control center of the ultrasonic testing equipment is activated, and the ultrasonic probe 7 is used to collect signals from the external water area. After the collection is completed, the ultrasonic probe 7 is retracted, and the telescopic rod 8 of the ultrasonic testing equipment is in the retracted state.

[0041] In this embodiment, the locking device of the wall-climbing robot 2 is released, and the wall-climbing robot 2 slides down to the next vertical measurement interval. t 2. Record the current height. h 2.

[0042] The process involves determining whether the wall-climbing robot 2 has reached the bottom surface of the steel pipe 3. If it has made contact with the bottom, the wall-climbing robot 2 is slid upwards and the detection device is retracted.

[0043] If the wall-climbing robot 2 does not reach the bottom of the steel pipe 3, repeat the following steps: Specifically, use a self-locking device to fix the robot at this height, and extend the telescopic rod 8 of the ultrasonic testing equipment until the ultrasonic probe 7 contacts the inside of the steel pipe 3 and stops. Activate the control center of the ultrasonic testing equipment, use the ultrasonic probe 7 to collect signals from the external water area, and after collection, release the locking device of the wall-climbing robot 2 and slide it down to the next vertical measurement interval. t 3. Record the current height. h 3.

[0044] S60. After data acquisition is completed, the detection equipment is retrieved, and the acquired ultrasonic echo signals are processed using ultrasonic echo signal processing methods to identify the scour boundary and scour depth around the bridge pier foundation.

[0045] In this embodiment, the ultrasonic echo signal processing method includes preprocessing the original ultrasonic echo signal; obtaining multiple IMF components using EEMD mode decomposition; selecting effective IMF components based on the correlation coefficient, energy ratio, and kurtosis index between each IMF component and the original signal; performing wavelet threshold noise reduction on the effective IMF components and reconstructing the signal; and extracting spectral feature parameters using FFT.

[0046] Among them, the spectral characteristics include one or more of the following: dominant frequency, band energy, echo delay, and amplitude attenuation.

[0047] Specifically, an ultrasonic echo signal processing method designed for steel pipe confinement environments was employed to process the acquired data. First, the original ultrasonic echo signal was preprocessed. Then, ensemble empirical mode decomposition (EEMD) was used to decompose the non-stationary signal into multiple intrinsic mode functions (IMFs). Effective IMF components were selected based on the correlation coefficient, energy proportion, and kurtosis index between each IMF component and the original signal, while interference components caused by steel pipe wall reflection, multipath propagation, and environmental noise were removed. Further, wavelet thresholding was used to denoise the effective IMF components and reconstruct the signal. Finally, Fast Fourier Transform (FFT) was used to extract multi-frequency domain characteristic parameters such as dominant frequency, band energy, echo delay, and amplitude attenuation to identify the scour boundary and scour depth around the bridge pier foundation.

[0048] Auxiliary noise is added to the preprocessed ultrasound signal, and multiple empirical mode decompositions (EEMD) are performed. The intrinsic mode functions (IMFs) of the same order obtained from each decomposition are processed to obtain several IMF components and residual terms. In one embodiment, the number of EEMD decompositions is 100 to 500, and the amplitude of the auxiliary noise is 0.1 to 0.3 times the standard deviation of the original signal; wavelet denoising uses one of the db4, sym6, or coif5 wavelet basis functions.

[0049] Furthermore, the IMF components obtained from EEMD decomposition are evaluated and analyzed. Specifically, the correlation coefficient, energy proportion, and kurtosis index between each IMF component and the original ultrasonic echo signal are calculated. The correlation coefficient characterizes the degree of correlation between the IMF component and the original signal; the energy proportion reflects the contribution of the component to the overall signal energy; and the kurtosis index characterizes the signal abrupt change characteristics. By combining these indicators, effective IMF components containing target echo information are selected, and interference components mainly caused by steel pipe wall reflection, water flow disturbance, and sediment scattering are removed, thereby improving the accuracy of subsequent spectral feature extraction.

[0050] Furthermore, wavelet thresholding denoising is used to perform multi-scale decomposition and soft thresholding on the effective IMF components, and the denoised effective IMF components are reconstructed to obtain the denoised ultrasonic echo signal.

[0051] Furthermore, FFT spectrum analysis was used to extract frequency domain characteristic parameters such as the main frequency, band energy, echo delay, and amplitude attenuation of the ultrasonic echo signal. Based on the variation law of ultrasonic echo characteristics at different depths, the depth of the scour boundary and scour pit 6 around the bridge pier foundation was identified.

[0052] Specifically, different vertical spacings were obtained. t 1, t 2, t 3, … t n By observing the scouring conditions, the scouring depth of the bridge foundation can ultimately be obtained. t=t 1 +t 2+… t n - h w The scouring conditions of pier 5 at different scouring depths were compared, and a scouring depth and distribution map of the pier foundation was generated. h w For riverbed foundation and h The distance between 1.

[0053] The technical solutions of the present invention have been fully described above. It should be noted that the specific embodiments of the present invention are not limited to the above description. All technical solutions formed by those skilled in the art based on the spirit and essence of the present invention by adopting equivalent transformations or equivalent transformations in terms of structure, method or function fall within the protection scope of the present invention.

Claims

1. A method for ultrasonic testing of bridge pier foundation scour using a wall-climbing robot, characterized in that, Includes the following steps: S10. Select a steel pipe of appropriate height and diameter based on the hydrological data of the area to be tested and the testing equipment, and transport the corresponding testing equipment and steel pipe to the area to be tested. S20. Submerge the steel pipe below the riverbed of the area to be tested, and place the wall-climbing robot equipped with ultrasonic testing equipment at the top inside the steel pipe. S30. Select an appropriate vertical measurement interval based on the height of the bridge pier foundation in the measured area, lower the wall-climbing robot equipped with ultrasonic testing equipment to the first vertical measurement interval, and fix the wall-climbing robot at that height; S40. Place the ultrasonic probe of the ultrasonic testing equipment against the inner wall of the steel pipe, turn on the control center of the ultrasonic testing equipment, and use the ultrasonic probe to collect the ultrasonic echo signal of the scour area around the bridge pier foundation. After the collection is completed, retract the ultrasonic probe. S50. Release the locking device of the wall-climbing robot, slide the wall-climbing robot down to the next vertical measurement interval, and repeat steps S30 and S40. S60. After data acquisition is completed, the detection equipment is retrieved, and the acquired ultrasonic echo data is processed using ultrasonic echo signal processing methods to identify the scour boundary and scour depth around the bridge pier foundation.

2. The ultrasonic detection method for bridge pier foundation scour using a wall-climbing robot according to claim 1, characterized in that, In step S50, the wall-climbing robot slides down to the next vertical measurement interval, and steps S30 and S40 are repeated. It is determined whether the wall-climbing robot has reached the bottom surface of the steel pipe. If it touches the bottom, the wall-climbing robot slides up and the detection device is retracted. If the wall-climbing robot has not reached the bottom of the steel pipe, steps S30 and S40 are repeated.

3. The ultrasonic detection method for bridge pier foundation scour using a wall-climbing robot according to claim 1, characterized in that, The ultrasonic testing equipment includes: a telescopic rod, an ultrasonic probe, and an ultrasonic equipment central system; the wall-climbing robot includes: a robot central control system, a robot sliding and adsorption device, and a robot support frame, one end of which is connected to the robot central control system and the other end of which is connected to the robot sliding and adsorption device. The central system of the ultrasound equipment is mounted on the central control system of the robot. One end of the telescopic rod is connected to the central system of the ultrasound equipment, and the other end is connected to the ultrasound probe.

4. The ultrasonic detection method for bridge pier foundation scour using a wall-climbing robot according to claim 3, characterized in that, The telescopic rod has a horizontal rotation function to enable the ultrasonic probe to move circumferentially along the inner wall of the steel pipe to collect signals, and there are no fewer than three ultrasonic probes to meet the needs of rapid acquisition.

5. The ultrasonic detection method for bridge pier foundation scour using a wall-climbing robot according to claim 3, characterized in that, During the sliding process of the wall-climbing robot, the telescopic rod of the ultrasonic testing equipment remains in a retracted state to ensure that the ultrasonic probe does not come into contact with the inner wall of the steel pipe.

6. The ultrasonic detection method for bridge pier foundation scour using a wall-climbing robot according to claim 1, characterized in that, In step S30, the vertical height at the first vertical measurement interval should be less than the water surface height.

7. The ultrasonic detection method for bridge pier foundation scour using a wall-climbing robot according to claim 1, characterized in that, In step S30, the vertical measurement spacing is selected according to the test requirements and there is no fixed spacing, as long as it meets the actual testing requirements.

8. The ultrasonic detection method for bridge pier foundation scour using a wall-climbing robot according to claim 1, characterized in that, The ultrasonic echo signal processing method includes preprocessing the original ultrasonic echo signal; obtaining multiple IMF components using EEMD mode decomposition; selecting effective IMF components based on the correlation coefficient, energy ratio, and kurtosis index between each IMF component and the original signal; performing wavelet threshold noise reduction on the effective IMF components and reconstructing the signal; and extracting spectral feature parameters using FFT.

9. The ultrasonic detection method for bridge pier foundation scour using a wall-climbing robot according to claim 8, characterized in that, The spectral characteristics include one or more of the following: dominant frequency, band energy, echo delay, and amplitude attenuation.

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