Pre-embedded sonar bridge pier scouring state monitoring system and method

Abstract

The invention relates to the technical field of bridge pier scouring state monitoring, and discloses a pre-embedded sonar bridge pier scouring state monitoring system and method, a sensor unit is pre-embedded in a bridge pier foundation, and the sensor unit comprises a sonar sensor, a lateral acoustic window and acoustic coupling liquid. The lateral acoustic window is exposed and automatically activates monitoring only when scour develops to a basic key area, and intelligent conversion from'whole process recording 'to'key early warning' is achieved. An electric pulse self-cleaning assembly is integrated, so that biological attachment on the acoustic window can be effectively removed through pulses generated by electrodes, and long-term reliability is ensured. All the units are coordinated through the control module. According to the invention, the direct, accurate, long-acting and maintenance-free automatic monitoring of the scouring of the pier foundation is realized, and the safety guarantee level of the bridge is obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pier scouring state monitoring, and in particular to a pre-embedded sonar pier scouring state monitoring system and method. BACKGROUND

[0002] Local scouring of the riverbed around the pier foundation is a major hidden danger threatening the safety of the bridge structure. At present, the monitoring of the scour pit mainly relies on the following three methods: 1. Artificial hydrological measurement, which is inefficient and has high risk during the flood period; 2. Water acoustic detection based on a water platform or a ship, which is easy to be damaged or displaced by water flow, resulting in data interruption at critical moments; 3. Installing sensors on the surface of the pier body, which can only indirectly infer the scouring condition and cannot directly obtain the soil loss state of the key area at the bottom of the pier foundation, which is the core of determining the bearing capacity of the foundation. Moreover, the surface of the sensor submerged in water for a long time is easily covered by organisms such as shellfish and algae, which seriously attenuates the acoustic signal, resulting in distorted monitoring data or even complete failure of the function.

[0003] Therefore, there is an urgent need in the art for a technical solution that can long-term, reliable and directly monitor the scouring state of the key area of the pier foundation. SUMMARY

[0004] To solve the above problems, the present application provides a pre-embedded sonar pier scouring state monitoring system and method. In the present monitoring system, the sensor itself is permanently protected from water flow impact and damage from floating objects; it can directly obtain the elevation data of the riverbed at the root of the foundation; and it has an effective mechanism to resist biological attachment, ensuring stable sensor performance without maintenance for a long time. The present application is implemented as follows:

[0005] A pre-embedded sonar pier scouring state monitoring system, comprising:

[0006] A sensor unit (1) is pre-embedded in the interior of the pier foundation (100), which includes a hollow cavity (11) and a sonar sensor (12) fixedly installed in the hollow cavity (11);

[0007] An acoustic window (13) is arranged on the side wall of the hollow cavity (11) and is buried by riverbed sediment at the initial stage of the construction of the pier;

[0008] An acoustic coupling liquid (14) is filled in the hollow cavity (11), which is water or a special acoustic coupling liquid, to form an acoustic wave transmission channel between the sonar sensor (12) and the acoustic window (13);

[0009] An electric pulse self-cleaning assembly integrated in the sensor unit (1), which comprises a pulse generating circuit and at least one pair of electrodes (2) arranged around the acoustic window (13);

[0010] A control module (3) arranged in the hollow cavity (11) or in other sealed cabin inside the pier foundation (100), which is electrically connected with the sonar sensor (12) and the electric pulse self-cleaning assembly;

[0011] Wherein, the sound wave emission direction of the sonar sensor (12) is configured to pass through the acoustic window (13) horizontally or obliquely upward and point to the riverbed area around the pier;

[0012] The control module (3) is configured to:

[0013] a. Control the sonar sensor (12) to work to emit sound waves and receive echo signals reflected from the riverbed surface after the riverbed scouring causes the acoustic window (13) to be exposed, and monitor the elevation change of the riverbed by calculating the sound wave slant range;

[0014] b. Control the electric pulse self-cleaning assembly to be started periodically or according to instructions to release electric pulses through the electrodes (2) to remove biological attachments on the acoustic window (13).

[0015] Further, the control module (3) is further configured to automatically trigger the work of the electric pulse self-cleaning assembly according to the echo signal strength fed back by the sonar sensor (12).

[0016] Further, the electrodes (2) are ring electrodes surrounding the acoustic window (13), or plate-shaped electrodes symmetrically arranged on both sides thereof.

[0017] Further, a plurality of the sensor units (1) are pre-buried around the pier foundation (100) at different depths and different horizontal positions; the sonar sensors (12) of all the sensor units (1) are communicatively connected with the control module (3), and the control module (3) is configured to integrate the slant range data of the sensors to calculate and construct a three-dimensional form of the scour pit around the pier.

[0018] Further, the control module (3) is communicatively connected with a data interface and / or a wireless transmission module (31) for outputting monitoring data and early warning information to an external data receiving terminal.

[0019] The application also discloses a pier scouring state monitoring method based on the above system, comprising the following steps:

[0020] S1: System pre-embedding and reference calibration

[0021] During the construction stage of the pier, at least one of the sensor units (1) is pre-embedded at a predetermined depth on the side surface of the pier foundation (100), and the three-dimensional spatial coordinates and the design elevation of the acoustic window (13) are accurately recorded;

[0022] After the completion of the pier and before the riverbed is significantly scoured, the initial riverbed elevation outside the acoustic window (13) is recorded by auxiliary measuring equipment, and this elevation value is stored in the control module (3) as the reference elevation;

[0023] S2: Intelligent triggering and adaptive monitoring

[0024] The control module (3) starts the sonar sensor (12) to detect at a predetermined period;

[0025] The control module (3) analyzes the received echo signal, if the signal strength is continuously below the first threshold value, it is determined that the acoustic window (13) is still buried by sediment, and the system returns to the dormant state; if the signal strength is higher than the first threshold value and the effective slant range can be calculated, it is determined that the acoustic window (13) has been exposed, and the system enters the active monitoring mode;

[0026] In the active monitoring mode, the control module (3) dynamically adjusts the monitoring frequency according to the measured scouring rate; when the scouring rate exceeds the set value, the monitoring frequency is automatically increased;

[0027] S3: Data fusion and three-dimensional reconstruction

[0028] When the system contains multiple sensor units (1), the control module (3) performs the following steps:

[0029] a. Control all sonar sensors (12) to emit sound waves synchronously, and collect the slant range data set of each sonar sensor (12) to the riverbed reflection point at the same time;

[0030] b. For each sonar sensor (12), according to its slant range, spatial coordinates and beam inclination angle, the riverbed elevation of its beam projection point is calculated through geometric triangular relationship;

[0031] c. All discrete elevation points calculated are reconstructed into the three-dimensional shape of the scour pit around the pier through spatial interpolation algorithm;

[0032] S4: Intelligent self-cleaning and early warning

[0033] In the active monitoring mode, if the control module (3) detects that the echo signal strength of a certain sonar sensor (12) decreases by more than a second threshold value relative to historical data, it is determined that biological attachment may exist in its acoustic window (13), and the operation of the electric pulse self-cleaning assembly is triggered at this time;

[0034] The control module (3) compares the real-time monitored riverbed elevation or reconstructed scour pit deepest depth with a plurality of preset safety thresholds, records the event and marks when the first warning threshold is reached, and immediately generates and sends alarm information to the remote monitoring center when the second warning threshold is reached.

[0035] Further, in step S3, the control module (3) also performs time sequence comparison on the three-dimensional morphology reconstructed at different time points, calculates the scour pit volume change amount and scour rate in a specified time period, and evaluates the scour development trend accordingly.

[0036] Compared with the prior art, the beneficial effects of the present application are:

[0037] Firstly, the core sensor unit of the present application is pre-embedded in the bridge pier foundation, which is permanently protected from structure, avoiding the risk of damage by flood, flowing ice and floating objects that easily hit the traditional externally installed equipment. The "built-in" design ensures that the monitoring system can survive and work continuously under extreme hydrological conditions, solving the problem of data interruption.

[0038] Secondly, the innovative "lateral acoustic window upward monitoring" design of the present application enables the sensor to directly detect the root of the bridge pier foundation and the most serious scour area. The "initially buried" feature constitutes an intelligent triggering mechanism, that is, the sensor does not work when there is no scour or the scour does not reach the foundation, and is only "activated" when the scour develops to the critical position that threatens the safety of the foundation, realizing the focus of the monitoring target from "full process recording" to "key warning", and saving energy.

[0039] Thirdly, the integrated electric pulse self-cleaning assembly of the present application ensures the long-term reliability of the equipment, automatically removes biological attachments on the acoustic window through a non-contact physical method, solves the problem of failure of underwater sensors due to performance degradation, realizes self-maintenance without human intervention, and significantly reduces the operation and maintenance cost and risk throughout the life cycle. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the application examples or the prior art or the descriptions needed in the prior art description, it is obvious that, without creative labor, other drawings can also be obtained by those skilled in the art according to these drawings. Figure 1A scene distribution diagram of a pre-buried sonar bridge pier scouring state monitoring system of the present application;

[0041] Figure 2 A structure schematic diagram of a pre-buried sonar bridge pier scouring state monitoring system of the present application;

[0042] Explanation of the reference numerals in the drawing:

[0043] 100 - bridge pier foundation;

[0044] 1 - sensor unit, 11 - hollow cavity, 12 - sonar sensor, 13 - acoustic window, 14 - acoustic coupling liquid;

[0045] 2 - electric pulse self-cleaning assembly, 21 - pulse generating circuit, 22 - electrode;

[0046] 3 - control module, 31 - data interface, 32 - wireless transmission module. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application.

[0048] A pre-buried sonar bridge pier scouring state monitoring system, comprising a sensor unit 1, an electric pulse self-cleaning assembly, and a control module 3;

[0049] The sensor unit 1 is pre-buried in the bridge pier foundation 100, which comprises a hollow cavity 11 and a sonar sensor 12 fixedly installed in the hollow cavity 11; an acoustic window 13 is arranged on the side wall of the hollow cavity 11 and is buried by riverbed sediment at the initial stage of bridge pier construction; the hollow cavity 11 is filled with acoustic coupling liquid 14, which is water or special acoustic coupling liquid, to form an acoustic wave conduction channel between the sonar sensor 12 and the acoustic window 13;

[0050] In the present embodiment, the hollow cavity 11 is a cylindrical sealed cabin body made of high-strength and corrosion-resistant 316L stainless steel or titanium alloy. The cabin body wall thickness needs to be calculated to withstand the impact force of concrete pouring, long-term hydrostatic pressure and chemical corrosion. The outer wall of the cabin body is designed with an anti-pulling annular groove or a welded shear key to ensure firm combination with the concrete.

[0051] The acoustic window 13 is made of wear-resistant material with similar acoustic impedance to concrete and river water, such as special polyurethane, ceramic or sapphire glass. Key performance is high acoustic transmission rate, resistance to silt wear and impact. Preferably, the acoustic window 13 is designed as a flat or slightly convex disc, which is fastened on the opening of the cavity side wall by a metal compression ring and a weather-resistant sealing ring, ensuring lifelong water tightness. The outer surface of the window is flush or slightly concave with the surface of the pier foundation to avoid construction damage.

[0052] The sonar sensor 12 is selected to have low power consumption and high frequency, suitable for accurate measurement of the riverbed morphology in close range. The acoustic wave emission direction of the sonar sensor 12 is configured to pass through the acoustic window 13 horizontally or obliquely upward and point to the riverbed area around the pier; in this embodiment, the sonar sensor 12 is fixed in the cavity by an internal support, with its acoustic wave emission central axis strictly aligned with the center of the acoustic window and inclined upward at an angle of 15° to 45° to optimally detect the evolution of the riverbed above the foundation side.

[0053] The acoustic coupling liquid 14 is preferably deionized water with added corrosion inhibitor and mildew inhibitor. Alternatively, a special acoustic coupling oil can be used to ensure stable sound speed and no bubbles, providing more consistent signal transmission.

[0054] The electric pulse self-cleaning assembly is integrated in the sensor unit 1, which includes a pulse generating circuit and at least one pair of electrodes 2 arranged around the acoustic window 13, which realizes automatic maintenance through the mechanism of electric pulse-electrolysis-physical impact; preferably, a pair of concentric ring electrodes is used, which are nested around the acoustic window. This layout can produce a uniform and powerful pulse electric field around the window, ensuring that there is no dead angle for cleaning. Or, plate-shaped electrodes can be symmetrically arranged above and below or left and right of the window to adapt to specific structural space limitations.

[0055] The electrode 2 uses a titanium electrode with a mixed metal oxide coating. This material is a key technology, and its coating greatly improves the electrochemical catalytic activity and corrosion resistance, ensuring stable performance and a service life matching the bridge foundation under long-term and frequent electrolytic pulse action.

[0056] The pulse generating circuit parameters are adjustable, and the pulse energy is dynamically optimized according to the actual situation of water conductivity and attached biological types, to achieve a balance between the lowest power consumption and the best cleaning effect.

[0057] The control module 3 is arranged in the hollow cavity 11 or independently arranged in other sealed cabins inside the pier foundation 100, and the control module 3 is electrically connected with the sonar sensor 12 and the electric pulse self-cleaning assembly 2; its hardware uses an industrial-grade low-power microcontroller as the core, which is integrated with sound wave transmission and reception circuit, data acquisition unit, cleaning control unit, etc.

[0058] The control module 3 is configured to:

[0059] a. Control the sonar sensor 12 to work to emit sound waves and receive echo signals reflected from the riverbed surface after the riverbed scouring causes the acoustic window 13 to be exposed, and monitor the elevation changes of the riverbed by calculating the slant range of the sound waves;

[0060] b. Control the electric pulse self-cleaning assembly to be periodically or on-demand activated to release electric pulses through the electrodes 2 to remove biological attachments on the acoustic window 13.

[0061] Further, the control module 3 is further configured to automatically trigger the work of the electric pulse self-cleaning assembly according to the echo signal strength fed back by the sonar sensor 12.

[0062] Further, a plurality of the sensor units 1 are pre-embedded around the pier foundation 100 at different depths and different horizontal positions; the sonar sensors 12 of all the sensor units 1 are in communication connection with the control module 3, and the control module 3 is configured to comprehensively calculate the slant range data of the sensors and construct a three-dimensional form of the scour pit around the pier. On this basis, the pulse generating circuit of the electric pulse self-cleaning assembly can be embeddedly installed in the sensor unit cavity to realize modularization; or integrated in the central control module to centrally manage the cleaning tasks of the plurality of sensor units.

[0063] Further, the control module 3 is in communication connection with a data interface and / or a wireless transmission module 31 for outputting the monitoring data and early warning information to an external data receiving terminal.

[0064] The application further discloses a pier scouring state monitoring method based on the above system, comprising the following steps:

[0065] S1: System pre-embedding and benchmarking

[0066] In the pier construction stage, according to the most dangerous area of the scour pit predicted by the hydrodynamic scouring model, the layout scheme of the sensor array is determined, at least one of the sensor units 1 is pre-embedded at a preset depth on the side surface of the pier foundation 100, and the three-dimensional spatial coordinates and the design elevation of the acoustic window 13 thereof are accurately recorded; the three-dimensional coordinates (X, Y, Z) of the center point of the acoustic window of the sensor unit and the inclination angle (θ) and the azimuth angle (φ) of the acoustic beam thereof are accurately recorded and input into the system database. As the cornerstone of all subsequent geometric calculations.

[0067] After the pier is built and before the riverbed is significantly scoured, the initial riverbed elevation outside the acoustic window 13 is recorded by an auxiliary measuring device, and this elevation value is stored in the control module 3 as the benchmark elevation;

[0068] S2: Intelligent triggering and adaptive monitoring

[0069] The control module 3 activates the sonar sensor 12 to detect at a preset period; for example, the control module activates the sonar once a week, transmits a short pulse, and collects the echo signal;

[0070] The control module 3 analyzes the received echo signal, if the signal strength is continuously lower than the first threshold value, it is determined that the acoustic window 13 is still buried by sediment, and returns to the dormant state; if the signal strength is higher than the first threshold value and the effective slant range can be calculated, it is determined that the acoustic window 13 has been exposed, and enters the active monitoring mode;

[0071] In the active monitoring mode, the control module 3 dynamically adjusts the monitoring frequency according to the measured erosion rate; when the erosion rate exceeds the set value, the monitoring frequency is automatically increased;

[0072] S3: Data fusion and three-dimensional reconstruction

[0073] When the system contains multiple sensor units 1, the control module 3 performs the following steps:

[0074] a. Control all sonar sensors 12 to transmit sound waves synchronously, and collect the slant range data set of each sonar sensor 12 to the riverbed reflection point at the same time; to overcome the dynamic interference of water flow, ships and other dynamic interference to the greatest extent, the control module instructs all sensor units to transmit sound waves synchronously within a very short time window, ensuring that the riverbed morphology "snapshot" at the same time is collected.

[0075] b. For each sonar sensor 12, according to its slant range, spatial coordinates and beam inclination, the riverbed elevation of its beam projection point is calculated through geometric triangular relationship;

[0076] c. All discrete elevation points calculated are reconstructed into the three-dimensional morphology of the scour pit around the pier through spatial interpolation algorithm;

[0077] Further, the three-dimensional morphology reconstructed at different time points is further compared in time sequence, the volume change of the scour pit and the erosion rate in a specified time period are calculated, and the erosion development trend is evaluated accordingly.

[0078] S4: Intelligent self-cleaning and early warning

[0079] In the active monitoring mode, if the control module 3 detects that the echo signal strength of a sonar sensor 12 decreases by more than a second threshold value relative to historical data, it is determined that the acoustic window 13 of the sonar sensor 12 may have biological attachment, and the work of the electric pulse self-cleaning assembly 2 is triggered;

[0080] The control module 3 compares the real-time monitored riverbed elevation or the reconstructed scour pit deepest depth with the preset multi-level safety threshold, when reaching the first warning threshold, records the event and marks, for example, when the elevation of any sensor monitoring point drops to 80% of the designed reserved minimum burial depth, the system records the event locally and marks in the daily data report, prompting the maintenance personnel to pay attention; when reaching the second warning threshold, immediately generate and send alarm information to the remote monitoring center, for example, when the deepest depth of the scour pit reaches or exceeds the designed reserved minimum burial depth, or the three-dimensional reconstruction shows that the scour pit morphology presents an unstable development trend, the control module immediately sends the highest level of alarm information to the monitoring center through wireless means, including but not limited to: alarm level, location, current maximum scour depth, scour rate, three-dimensional morphology diagram, etc., providing comprehensive data support for emergency decision-making.

[0081] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A pre-embedded sonar-based system for monitoring the scouring state of a bridge pier, characterized in that, The application comprises: a sensor unit (1) embedded in a bridge pier foundation (100), which comprises a hollow cavity (11) and a sonar sensor (12) fixedly installed in the hollow cavity (11); an acoustic window (13) arranged on the side wall of the hollow cavity (11) and buried by riverbed sediment at the initial stage of bridge pier construction; an acoustic coupling liquid (14) filled in the hollow cavity (11), which is water or a special acoustic coupling liquid, used to form an acoustic wave transmission channel between the sonar sensor (12) and the acoustic window (13); an electric pulse self-cleaning assembly integrated in the sensor unit, which comprises a pulse generating circuit and at least one pair of electrodes (2) arranged around the acoustic window (13); a control module (3) arranged in the hollow cavity (11) or independently arranged in other sealed cabins inside the bridge pier foundation (100), which is electrically connected with the sonar sensor (12) and the electric pulse self-cleaning assembly; wherein the acoustic wave emission direction of the sonar sensor (12) is configured to pass through the acoustic window (13) horizontally or obliquely upward and point to the riverbed area around the bridge pier; the control module (3) is configured to: a. control the sonar sensor (12) to work to emit acoustic waves and receive echo signals reflected from the riverbed surface after the acoustic window (13) is exposed due to riverbed erosion, and monitor the elevation change of the riverbed by calculating the acoustic slant range; b. control the electric pulse self-cleaning assembly to be started periodically or according to instructions to release electric pulses through the electrodes (2) to remove biological attachments on the acoustic window (13).

2. The pre-embedded pier scour monitoring system of claim 1, wherein, The control module (3) is further configured to automatically trigger the work of the electric pulse self-cleaning assembly according to the echo signal strength fed back by the sonar sensor (12).

3. The pre-embedded pier scour monitoring system of claim 2, wherein, The electrodes (2) are ring electrodes surrounding the acoustic window (13) or plate electrodes symmetrically arranged on both sides thereof.

4. The pre-embedded pier scour monitoring system of claim 1 to 3, wherein, A plurality of the sensor units (1) are embedded at different depths and different horizontal positions around the bridge pier foundation (100); the sonar sensors (12) of all the sensor units (1) are communicatively connected with the control module (3), and the control module (3) is configured to integrate the slant range data of all the sensors to calculate and construct a three-dimensional form of the scour pit around the bridge pier.

5. The pre-embedded pier scour monitoring system of claim 1, wherein, The control module (3) is communicatively connected with a data interface and / or a wireless transmission module (31) for outputting monitoring data and warning information to an external data receiving terminal.

6. A method of monitoring the scouring state of a pier based on the system according to any one of claims 1 to 5, characterized by, The application comprises the following steps: S1: system embedding and reference calibration During the construction stage of the bridge pier, at least one sensor unit (1) is embedded at a preset depth on the side surface of the bridge pier foundation (100), and the three-dimensional spatial coordinates and design elevation of the acoustic window (13) thereof are accurately recorded. After the bridge pier is built and before the riverbed is significantly eroded, an auxiliary measuring device is used to record the initial riverbed elevation outside the acoustic window (13), and this elevation value is stored in the control module (3) as a reference elevation; S2: Intelligent triggering and adaptive monitoring The control module (3) activates the sonar sensor (12) for detection at a preset period; The control module (3) analyzes the received echo signal. If the signal strength is continuously below the first threshold value, it is determined that the acoustic window (13) is still buried by sediment, and the system returns to the dormant state. If the signal strength is higher than the first threshold value and the effective slant range can be calculated, it is determined that the acoustic window (13) has been exposed, and the system enters the active monitoring mode; In the active monitoring mode, the control module (3) dynamically adjusts the monitoring frequency according to the measured erosion rate. When the erosion rate exceeds the set value, the monitoring frequency is automatically increased; S3: Data fusion and three-dimensional reconstruction When the system contains multiple sensor units (1), the control module (3) performs the following steps: a. Control all sonar sensors (12) to emit sound waves synchronously, and collect the slant range data set of each sonar sensor (12) to the riverbed reflection point at the same time; b. For each sonar sensor (12), according to its slant range, spatial coordinates and beam inclination angle, the riverbed elevation of its beam projection point is calculated through geometric triangular relationship; c. All discrete elevation points calculated are reconstructed into the three-dimensional form of the erosion pit around the bridge pier through spatial interpolation algorithm; S4: Intelligent self-cleaning and early warning In the active monitoring mode, if the control module (3) detects that the echo signal strength of a sonar sensor (12) decreases by more than the second threshold value compared to historical data, it is determined that there may be biological attachment to its acoustic window (13), and the electric pulse self-cleaning component (2) is triggered to work once; The control module (3) compares the real-time monitored riverbed elevation or the reconstructed deepest depth of the erosion pit with the preset multi-level safety threshold. When the first warning threshold is reached, the event is recorded and marked; When the second warning threshold is reached, an alarm message is immediately generated and sent to the remote monitoring center.

7. The method of claim 6, wherein, In step S3, the control module (3) also performs time series comparison on the three-dimensional forms reconstructed at different time points, calculates the volume change of the erosion pit and the erosion rate in a specified time period, and evaluates the erosion development trend accordingly.

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