CN-122015473-A - Main cable dehumidification system and dehumidification method for suspension bridge based on distributed humidity monitoring

CN122015473ACN 122015473 ACN122015473 ACN 122015473ACN-122015473-A

Abstract

The invention discloses a distributed humidity monitoring-based suspension bridge main cable dehumidification system and a distributed humidity monitoring-based suspension bridge main cable dehumidification method, which belong to the field of humidity monitoring and dehumidification of suspension bridge main cables and comprise a three-dimensional humidity monitoring network, an optical fiber demodulator, an intelligent control module and a distributed dehumidification module, wherein the three-dimensional humidity monitoring network is embedded or embedded into the suspension bridge main cable, the three-dimensional humidity monitoring network is electrically connected with the optical fiber demodulator through an outgoing line, the optical fiber demodulator is electrically connected with an input end of the intelligent control module, and an output end of the intelligent control module is connected with the distributed dehumidification module. By adopting the suspension bridge main cable dehumidification system and the dehumidification method based on distributed humidity monitoring, the problems of large humidity gradient, inaccuracy in single-point monitoring, rough dehumidification control and the like in a large-section main cable are solved, visual early warning and linkage precise protection of the corrosion environment in the main cable can be realized, and the durability and safety of the suspension bridge main cable are remarkably improved.

Inventors

LIU SHENGCHUN
Wu Jiaomeng
NING TIGANG
ZHANG BINGBING
ZHAI YUANBO
Zhong Zijun
WU YI
YU HENG
FAN WENXIAO

Assignees

交大为达(北京)科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260320

Claims (9)

1. The system is characterized by comprising a three-dimensional humidity monitoring network, an optical fiber demodulator, an intelligent control module and a distributed dehumidification module, wherein the three-dimensional humidity monitoring network is implanted or embedded into the main cable of the suspension bridge, the three-dimensional humidity monitoring network comprises a plurality of grating humidity sensing optical fibers which are axially and generally arranged in the main cable of the suspension bridge, the plurality of grating humidity sensing optical fibers are arranged in a multi-layer annular array along the transverse section of the main cable of the suspension bridge, and a plurality of humidity sensitive grating measuring points are uniformly inscribed on the grating humidity sensing optical fibers; The three-dimensional humidity monitoring network is electrically connected with the optical fiber demodulator through the outgoing line, the optical fiber demodulator is electrically connected with the input end of the intelligent control module, and the output end of the intelligent control module is connected with the distributed dehumidification module.
2. The system for dehumidifying a main cable of a suspension bridge based on distributed humidity monitoring as set forth in claim 1, wherein the distributed dehumidifying module comprises a dehumidifier unit and a plurality of cable clamp pairs axially spaced on the main cable of the suspension bridge, the cable clamp pairs comprise an air inlet cable clamp and an air outlet cable clamp, the air inlet cable clamp is communicated with the air outlet end of the dehumidifier unit through an air inlet pipeline to form an air blowing dehumidifying passage of the dehumidifier unit, the air inlet cable clamp, the main cable of the suspension bridge and the air outlet cable clamp; an electric regulating valve is arranged on the air inlet cable clamp, and the electric regulating valve and the dehumidifying unit are connected with the intelligent control module.
3. The distributed humidity monitoring-based suspension bridge main cable dehumidification system as claimed in claim 2, wherein the spatial resolution of the optical fiber demodulator is more than 0.5m, and the humidity measurement precision is not lower than +/-2% RH.
4. The dehumidification method of the main cable dehumidification system of the suspension bridge based on distributed humidity monitoring as set forth in claim 2 or 3, comprising the following steps: The method comprises the steps of S1, arranging a three-dimensional humidity monitoring network, wherein in the process of bundling a plurality of steel wires into a suspension bridge main cable, a plurality of grating humidity sensing optical fibers are planted into the plurality of steel wires in a multi-layer annular array, or the plurality of grating humidity sensing optical fibers are embedded into steel wire gaps of the suspension bridge main cable in the multi-layer annular array, or the plurality of grating humidity sensing optical fibers are packaged by a fiber composite material to form a composite sensing unit with the same size as the steel wires of the suspension bridge main cable so as to replace a plurality of steel wires in the main cable, and the composite sensing unit is connected with an optical fiber demodulator by an outgoing line; S2, initializing and starting the system, transmitting laser to a grating humidity sensing optical fiber by using an optical fiber demodulator, receiving a reflected signal from a humidity sensing grating measuring point, determining the measuring point position by using the optical fiber demodulator according to an optical time domain reflection principle, calculating a humidity value by monitoring the Bragg wavelength drift amount of the reflected signal, generating a three-dimensional humidity distribution map in a main cable of the suspension bridge, and transmitting the humidity distribution map and positioning data to an intelligent control module; S3, the intelligent control module invokes a built-in humidity gradient analysis algorithm, performs global analysis on the received three-dimensional humidity distribution data, calculates the humidity gradient change in the main cable, identifies a high humidity area, a humidity abnormal point and corresponding space coordinates, and simultaneously judges an air inlet cable clamp regulation and control partition to which the high humidity area belongs; S4, the intelligent control module generates a targeted dehumidification instruction according to the humidity value, the range and the distribution characteristics of the high-humidity area, wherein the dehumidification instruction comprises an opening parameter of an electric regulating valve corresponding to the partition air inlet cable clamp, a working state parameter of a dehumidification unit and an air supply duration threshold, the dehumidification unit is driven to start or adjust output power through a control signal, and the electric regulating valve of the target partition air inlet cable clamp is independently regulated and controlled to directionally convey dry air to the high-humidity area, so that partition dehumidification is realized; And S5, continuously acquiring humidity data in the main cable of the suspension bridge by the three-dimensional humidity monitoring network in the dehumidification process, updating a three-dimensional humidity distribution map by the optical fiber demodulator in real time and feeding back to the intelligent control module, dynamically tracking the humidity change trend of the high-humidity area by the intelligent control module, sending a feedback instruction by the intelligent control module when the humidity value of the target high-humidity area is monitored to be lower than a preset safety threshold value, adjusting the opening of a corresponding electric regulating valve and the power of the dehumidifier unit, and recovering the power to the normal running state, and continuously optimizing the air supply parameter if the humidity does not reach the standard, forming closed-loop dehumidification regulation and control, and ensuring that the whole area of the main cable maintains a low-humidity safety environment.
5. The method for dehumidifying a main cable dehumidification system of a suspension bridge based on distributed humidity monitoring as set forth in claim 4, wherein the step S2 comprises the steps of: s21, after the system is initialized, the optical fiber demodulator transmits broadband laser to the grating humidity sensing optical fiber implanted in the main cable of the suspension bridge and receives reflected light; S22, based on the reflected light, the optical fiber demodulator determines the position of the measuring point according to the optical time domain reflection principle: ; Wherein, the ; In the formula, 、 And Respectively representing an axial coordinate, a radial coordinate and a circumferential coordinate; the initial length of the axial layout of the grating humidity sensing optical fiber is represented; Represent the first A preset radius of the radial annular layers; Representing the first layer in the same ring layer The preset circumferential angle of the root grating humidity sensing optical fiber; representing the length of the optical fiber between the measuring point and the optical fiber demodulator; Representing the speed of light in vacuum; representing the time delay between the emission of the laser pulse and the receipt of the reflected pulse from a particular humidity sensitive grating measurement point; representing the effective refractive index of the grating humidity sensing optical fiber; meanwhile, the humidity value is calculated by monitoring the drift amount of the Bragg wavelength of the reflected signal: ; Wherein, the ; In the formula, Indicating the current relative humidity value at the measurement point, Representing a reference humidity value; Representing the current Bragg wavelength of the reflected light from a certain measuring point, which is measured in real time by the optical fiber demodulator; a humidity sensitivity coefficient representing a humidity sensitive grating; The initial Bragg wavelength obtained by calibrating the same humidity sensitive grating measuring point in a reference humidity environment is represented; Represents the amount of shift in Bragg wavelength, an ; Indicating the amount of change in relative humidity; S23, executing the step S2 in the optical fiber demodulator for all the humidity sensitive grating measuring points in the main cable of the suspension bridge, and then carrying out three-dimensional space coordinates of each measuring point Real-time humidity value corresponding to the humidity value And (3) performing association and combination, and generating a visual three-dimensional humidity distribution map of the interior of the main cable of the suspension bridge in software through a spatial interpolation algorithm.
6. The method for dehumidifying a main cable dehumidification system of a suspension bridge based on distributed humidity monitoring as set forth in claim 5, wherein the step S3 comprises the steps of: s31, extracting multidimensional features, namely extracting structured data from the three-dimensional humidity distribution map to obtain a real-time three-dimensional humidity distribution matrix ; At the same time, the following features are extracted from the history database: Spatial gradient characterization Calculating the humidity gradient amplitude of each measuring point in a three-dimensional space: ; In the formula, Indicating the measuring point Humidity gradient magnitude in three-dimensional space; indicating the measuring point Is a spatial neighborhood of (b); Is a distance weight; indicating the measuring point Spatial neighborhood of (a) Index of a certain measuring point in the database; And Respectively represent the current measuring points Corresponding real-time humidity value and spatial neighborhood Internal measuring point Corresponding real-time humidity values; time rate of change characteristics Calculating the humidity of each measuring point in a certain time window Trend of change in: ; In the formula, Indicating the measuring point At the moment of time Humidity time rate of change characteristics of (a); And Respectively represent measuring points At the current moment Time and date Corresponding real-time humidity values; statistical anomaly characterization Calculating the deviation degree of the current humidity value relative to the history distribution based on the long-term history humidity data of the measuring point or the area where the measuring point or the area is located: ; In the formula, Indicating the measuring point At the moment of time Humidity statistics anomaly characteristic of (2); indicating the measuring point The average value of the corresponding long-term historical humidity data; indicating the measuring point Standard deviation of the corresponding long-term historical humidity data; Absolute humidity value The current real-time humidity value of the measuring point is used as an absolute humidity value ; S32, establishing a dynamic risk scoring function For comprehensively evaluating measuring points Risk of humidity abnormality of (2): ; In the formula, Representing an absolute humidity influence function; Representing a spatial gradient influence function; Representing a time rate of change impact function; representing a statistical anomaly impact function; each representing a dynamic weight coefficient of each feature, and ; S33, setting a dynamic risk scoring threshold value , 、、、 And All represent weight coefficients; And Respectively represent time of day The humidity mean value and standard deviation of all measuring points of the main cable of the suspension bridge after normalization; representing a season correction factor; Representing a historical humidity deviation coefficient; Representing the local high-humidity measuring point duty ratio; S34, all Marking the measuring points as risk points, and aggregating all the risk points into one or more continuous three-dimensional space risk areas by using a DBSCAN algorithm based on space distance; s35, calculating an average risk score of the three-dimensional space risk region And according to the average risk score Dividing the dehumidification intensity strategy into different grades, and generating the dehumidification intensity strategy according to the classified grades; Meanwhile, calculating the geometric center coordinates of each three-dimensional space risk area, and determining the regulation and control range of the air inlet cable clamp corresponding to the area by combining a pre-established cable clamp partition-three-dimensional space mapping table; s35, outputting a list of three-dimensional space risk areas to obtain target wet areas, wherein each area comprises a space boundary, a risk level, a core humidity characteristic, a dehumidification intensity strategy and an air inlet cable clamp ID list responsible for regulation and control.
7. The method for dehumidification of a suspension bridge main cable dehumidification system based on distributed humidity monitoring as set forth in claim 6, wherein in step S5, when the humidity of the target high humidity area does not fall to a safety threshold within an expected time When the PID control concept is adopted, the system starts an adaptive air supply parameter optimization algorithm based on the PID control concept; The method comprises the following specific steps: Firstly, setting an optimization target as humidity deviation And (2) and , Indicating that the humidity value is monitored in real time, Representing a safety threshold; Setting the evaluation index as the dehumidification response rate And (2) and Setting air supply parameters, namely opening degree of electric regulating valve Power of dehumidifier unit Duration of air supply ; And then adopting an incremental PID control algorithm to adjust the air supply parameters: ; In the formula, Indicating the valve opening adjustment amount; representing a scaling factor; representing an integral coefficient; representing the differential coefficient; if the humidity still does not reach the standard, the system starts a multi-parameter collaborative optimization module, and the system is adjusted according to the following rules: If it is If it is determined that the humidity is slowly decreased, the humidity is increased And And increase Extension of Until reaching the standard; Representing a minimum allowable dehumidification response rate; If it is Then increase And reduce Until reaching the standard; Indicating the maximum allowable humidity deviation change rate; If it is Starting the history data learning module, calling the optimal parameter combination under the same working condition, and adjusting by adopting a fuzzy control strategy , , Weights of (2); Representing an initial time; the system records the initial humidity distribution of each regulation Combination of parameters of air supply Final humidity response Response time And establishing an experience database, and directly calling historical optimal parameters when the same humidity distribution mode appears again.
8. The method of claim 7, further comprising step S6 of summarizing historical humidity distribution data after step S5, and generating a corrosion trend of the main cable of the suspension bridge based on the historical humidity distribution data.
9. The dehumidification method of the main cable dehumidification system of the suspension bridge based on distributed humidity monitoring of claim 8, wherein in step S6, the system quantitatively evaluates and predicts trend of corrosion development of different areas inside the main cable of the suspension bridge by summarizing historical three-dimensional humidity distribution data monitored for a long time and combining a steel wire corrosion dynamics model; The specific generation method is as follows: s61, data preparation and feature extraction, namely extracting the following data sequence from a historical database, namely a humidity time sequence Measuring point At the time of Relative humidity value, temperature time series of (c) And (3) time tag: spatial coordinates: ; S62, establishing a humidity-dependent corrosion rate model: ; In the formula, Indicating the measuring point At the time of Is a corrosion rate of (a); indicating a corrosion rate constant; Representing real-time relative humidity; Indicating a corrosion threshold humidity; indicating a humidity impact index; Represents a temperature influence function, an , The activation energy is represented by the energy of the activation, The gas constant is represented by a value of, Representing a reference temperature; s63, calculating the cumulative corrosion depth based on a corrosion rate model dependent on humidity: ; In the formula, Indicating the measuring point From the initial time To the current time Is a cumulative corrosion depth; representing a monitoring time interval; Representing the total sampling times of the monitoring data; indicating the measuring point At the moment of time Is a transient corrosion rate of (a); indicating the measuring point In the first place Sub-sampling time Is a corrosion rate of (a); S64, accumulating corrosion depth sequences based on history Adopting a time sequence prediction model to predict corrosion trend in a future period of time; The predictive formula expression is as follows: ; In the formula, Representing future Predicted corrosion depth after time; And All represent linear trend coefficients; And Respectively represent the first Each seasonal period term And the trend decomposition model expression is as follows: ; In the formula, Representing a long-term trend term; A seasonal period item; representing random noise; s65, risk level classification: Safety: ; Early warning: ; High risk: ; S66, outputting a corrosion depth distribution map, a trend prediction curve and divided risk levels, and exceeding the predicted corrosion depth in the future And the system automatically gives out early warning.

Description

Main cable dehumidification system and dehumidification method for suspension bridge based on distributed humidity monitoring Technical Field The invention relates to the technical field of humidity monitoring and dehumidification of suspension bridge main cables, in particular to a distributed humidity monitoring-based suspension bridge main cable dehumidification system and a distributed humidity monitoring-based suspension bridge main cable dehumidification method. Background The main cable of the suspension bridge is used as a bridge core bearing member, the structural integrity and durability of the main cable directly determine the overall safety performance, service life and operation reliability of the suspension bridge, and the main cable is a key core member for guaranteeing long-term stable operation of the bridge. The main cable is usually formed by twisting tens of thousands of high-strength galvanized steel wires, the corrosion rate of the high-strength steel wires is obviously and positively correlated with the relative humidity of the environment where the high-strength steel wires are located, namely, the increase of the humidity accelerates the loss of a galvanized layer on the surface of the steel wires and the electrochemical corrosion reaction of base steel, so that the mechanical property of the main cable is attenuated, and the structural potential safety hazard is possibly caused when the corrosion rate is serious, and even the bridge operation safety is threatened. In order to delay the corrosion process of the steel wires in the main cable and prolong the service life of the main cable, a main cable dehumidification system is generally adopted in the field of engineering at present as a core protection means, and the core principle is that dry air is continuously introduced into the main cable to reduce the relative humidity of the internal environment and create a low-humidity environment which is unfavorable for corrosion of the steel wires, so that the aim of corrosion prevention and protection is fulfilled. However, the existing main cable dehumidifying system and the matched monitoring technology still have the following key technical defects in practical engineering application, and the actual requirement of high-precision protection of the main cable of the large-span suspension bridge is difficult to meet: 1. The monitoring means are extensive and the data are on the one hand, and the control logic of the current main stream dehumidification system is mostly dependent on single-point electronic humidity sensors distributed near the air inlet cable clamps and the air outlet cable clamps to collect data. However, for a large-span suspension bridge, the section diameter of the main cable can be more than 1 meter, the main cable is influenced by the structural characteristics of the main cable, the permeation of the external environment, the air flow distribution difference and the like, the internal humidity distribution of the main cable shows obvious three-dimensional gradient characteristics, and the uniformity of a humidity field is extremely poor. The single-point monitoring can only acquire the humidity data of local point positions, cannot comprehensively and accurately capture the global humidity distribution rule in the main cable, and is more difficult to reflect humidity differences of different radial layers and different axial areas, so that serious deviation exists in judging the real corrosion environment in the main cable. 2. Because of the unilateral nature of the monitoring data, the control strategy of the existing dehumidification system is not specific, and a rough integral dehumidification mode is mostly adopted, namely, uniform air supply parameters (air quantity and duration) are adopted for dehumidification no matter how the humidity of each area in the main cable is. On the one hand, the mode can lead to insufficient dehumidification in a high-humidity area and can not effectively inhibit corrosion, and on the other hand, the mode can lead to excessive dehumidification in a low-humidity area and cause a great amount of energy waste. 3. The corrosion state is difficult to predict and the maintenance is lack of basis, wherein the main cable is of a closed composite structure, the inner steel wires are wrapped in the protective layer and the twisting structure, and the corrosion state cannot be directly observed or estimated. In the prior art, corrosion risks can be estimated indirectly only through single-point humidity data, quantitative association between humidity distribution and steel wire corrosion rate cannot be established, corrosion development trend is difficult to predict based on monitoring data, so that bridge maintenance work is in a 'maintenance after the fact' state, scientific and effective preventive maintenance basis is lacked, and structural safety risks caused by main cable corrosion cannot be avoided from the source. Disclosure of