Bridge and tunnel health state monitoring method

Abstract

The invention discloses a bridge and tunnel health state monitoring method, which relates to the technical field of bridge and tunnel monitoring, and comprises the following steps of: planning and designing a monitoring system, installing and debugging a sensor, setting a data acquisition system, performing data transmission encryption transmission and preprocessing, performing data analysis and feature extraction, performing state evaluation and early warning and the like. Potential risks of a bridge or a tunnel can be found and early warned in time by determining acquisition frequency and time intervals, establishing a data storage format and a database, and performing encryption transmission and preprocessing on data transmission, and meanwhile, related personnel can receive alarm information in time by setting an early warning threshold value and an alarm mechanism, so that the safety of the bridge or the tunnel is ensured. A sensor and a strain gauge are selected according to selected monitoring parameters to measure strain, such as a resistance strain gauge, strain data are acquired by utilizing the characteristic that the resistance value of the resistance strain gauge changes along with strain, and a displacement sensor comprises a linear variable differential transformer and the like and can accurately measure the displacement change of the structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of bridge and tunnel monitoring, and particularly relates to a method for monitoring the health status of bridges and tunnels. Background Art

[0002] Based on long-term health monitoring and periodic structural reviews, collecting status information to evaluate the health status and load-bearing capacity of bridges and tunnels is crucial for ensuring the safe operation of buildings.

[0003] The existing method for monitoring the health status of bridges and tunnels based on fuzzy theory with the application number 202311204603.9 includes hierarchically dividing the specified connection structure of bridges and tunnels and extracting evaluation indicators; using the entropy weight method for objective weight analysis and combining with the form of expert questionnaires for subjective weight setting to finally determine the comprehensive weight of each indicator; converting the regular inspection results and real-time data streams of health monitoring of bridges and tunnels into membership functions through fuzzy evaluation theory for fusion; accumulating the fuzzy membership degrees and weights layer by layer through weighted summation to obtain the overall structural evaluation result; and forming the integrated health status monitoring result of bridges and tunnels according to the overall structural evaluation result. The present invention realizes the health status evaluation of the operation status of bridge and tunnel clusters.

[0004] During the process of monitoring the health status of bridges and tunnels by the above method, potential risks of bridges or tunnels cannot be detected and warned in time. Therefore, we provide a method for monitoring the health status of bridges and tunnels to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for monitoring the health status of bridges and tunnels. The specific steps of the method for monitoring the health status of bridges and tunnels are as follows:

[0006] S1: Monitoring system planning and design;

[0007] S2: Sensor installation and debugging;

[0008] S3: Setting up the data acquisition system;

[0009] S4: Data transmission, encrypted transmission and preprocessing;

[0010] S5: Data analysis and feature extraction;

[0011] S6: Status evaluation and warning.

[0012] The present invention is further configured such that the specific manner of the monitoring system planning and design is as follows:

[0013] S101: Determining the monitoring objectives and scope, specifically the main girders, piers, and abutments of bridges and tunnels, and the linings and surrounding rocks of tunnels;

[0014] S102: Select monitoring parameters. According to the structural characteristics and possible diseases of the bridge and tunnel, select appropriate monitoring parameters;

[0015] S103: Determine the type and layout scheme of sensors. Select sensors according to the selected monitoring parameters. Strain gauges are used to measure strain, such as resistance strain gauges, and utilize the characteristic that their resistance values change with strain to obtain strain data.

[0016] The present invention is further configured such that the specific method for installing and debugging the sensors is as follows:

[0017] S201: Specific installation of sensors. Operate strictly in accordance with the installation instructions of the sensors;

[0018] S202: Sensor debugging. After installation, the sensors need to be debugged. First, perform static debugging to check whether the initial readings of the sensors are normal, and then perform dynamic debugging. By simulating actual load or deformation conditions, check whether the response of the sensors is sensitive and accurate.

[0019] The present invention is further configured such that the specific method for setting up the data acquisition system is as follows:

[0020] S301: Determine the acquisition frequency and time interval. Determine the data acquisition frequency according to factors such as the traffic flow and usage environment of the bridge and tunnel. The setting of the acquisition time interval should consider being able to comprehensively reflect the state changes of the structure at different time periods;

[0021] S302: Establish a data storage format and database. Specifically, design a reasonable data storage format, classify and store the acquired data according to information such as sensor type, installation location, and acquisition time. A database management system can be used to establish a data table structure to facilitate data query, management, and analysis.

[0022] The present invention is further configured such that the specific method for encrypted transmission and preprocessing of the data is as follows:

[0023] S401: Select an appropriate transmission method according to factors such as the geographical location, on-site environment, and data volume of the bridge and tunnel, and encrypt the data during transmission;

[0024] S402: Configure transmission equipment and network. If wired transmission is adopted, cables or optical fibers need to be laid, and corresponding signal conversion equipment needs to be configured to ensure that data can be correctly converted and transmitted in different transmission media. For wireless transmission, install wireless transmitters and receivers and set correct communication parameters, such as frequency band, transmission rate, and IP address;

[0025] S403: Data cleaning, removing outliers and noise in the collected data. Outliers may be caused by sensor failures, electromagnetic interference, human factors, etc. Statistical methods can be used to identify outliers. That is, if a data point deviates from the average value by more than 3 times the standard deviation, it is considered an outlier and will be removed. For noise data, filtering methods can be used for processing. For example, low-pass filtering can remove high-frequency noise;

[0026] S404: Data calibration and normalization. According to the calibration parameters of the sensor, the data is calibrated to ensure the accuracy of the data. Normalization processing can unify data of different magnitudes into a certain range for easy comparison and analysis. Common normalization methods include min-max normalization, which maps the data to the interval [0,1]. The calculation formula is:

[0027]

[0028] where: x is the original data, x_{min} is the minimum value of the data, and x_{max} is the maximum value of the data.

[0029] The present invention is further configured such that the specific manner of the data analysis and feature extraction is:

[0030] S501: Structural mechanics analysis. Using the principles of structural mechanics, parameters such as internal force and stress of the structure are calculated based on the collected strain, displacement and other data;

[0031] S502: Feature extraction. Extract features from the preprocessed data that can reflect the health status of the bridge and tunnel. For example, statistical features such as the peak value, mean value, and standard deviation of the strain are extracted. These features can reflect the force change of the structure under the action of loads. For displacement data, features such as the change rate of displacement and the cumulative displacement amount can be extracted.

[0032] The present invention is further configured such that the specific manner of the status evaluation and early warning is:

[0033] S601: Establish an evaluation model. Analytic hierarchy process, fuzzy comprehensive evaluation method, etc. can be used to establish a bridge and tunnel health status evaluation model. The analytic hierarchy process stratifies the evaluation indicators, determines the weights of each indicator by constructing a judgment matrix, and then comprehensively calculates to obtain the health status score of the structure. The fuzzy comprehensive evaluation method takes into account the fuzziness of the evaluation indicators, and conducts a fuzzy comprehensive evaluation of the structure health status by establishing a fuzzy relation matrix and determining the membership function;

[0034] S602: Set warning thresholds and alarm mechanisms. According to the design standards, specification requirements, and past engineering experience of the structure, set warning thresholds at different levels. When the monitored data exceeds the corresponding threshold, trigger the alarm mechanism. The alarm methods can include various methods such as sound alarms, SMS notifications, and system interface prompts to ensure that relevant personnel can receive alarm information in a timely manner.

[0035] The present invention has the following beneficial effects:

[0036] Through scientific monitoring such as the planning and design of the monitoring system, the installation and debugging of sensors, the setting of the data acquisition system, the encrypted transmission and preprocessing of data, data analysis and feature extraction, and status evaluation and early warning, and by determining the acquisition frequency and time interval, establishing the data storage format and database, and the encrypted transmission and preprocessing of data transmission, the present invention can timely detect and warn of potential risks of bridges or tunnels. At the same time, by setting warning thresholds and alarm mechanisms, it is ensured that relevant personnel can receive alarm information in a timely manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments:

[0038] Figure 1 It is a schematic diagram of the overall structure of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The following will describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments:

[0040] Please refer to Figure 1 , the present invention is a method for monitoring the health status of bridges and tunnels. The specific steps of the method for monitoring the health status of bridges and tunnels are as follows:

[0041] S1: Planning and design of the monitoring system;

[0042] S2: Installation and debugging of sensors;

[0043] S3: Setting up the data acquisition system;

[0044] S4: Encrypted transmission and preprocessing of data transmission;

[0045] S5: Data analysis and feature extraction;

[0046] S6: Status evaluation and early warning.

[0047] Specifically, the specific method for the planning and design of the monitoring system is:

[0048] S101: Determine the monitoring targets and scope, specifically the main girders, piers, and abutments of bridges and tunnels, and the linings and surrounding rocks of tunnels. Different parts face different risks and are prone to different diseases during long-term use. For example, the main girders of bridges are susceptible to fatigue damage caused by vehicle loads, while piers require key attention to foundation settlement and scour conditions; tunnel linings may develop cracks and water leakage, and surrounding rocks may experience loosening and deformation.

[0049] S102: Select monitoring parameters. Based on the structural characteristics and possible diseases of bridges and tunnels, select appropriate monitoring parameters. For example, for bridge structures, strain is a key parameter. By installing strain gauges at key sections, the internal force changes of the structure under load can be monitored; displacement parameters are used to monitor the overall deformation of the structure, such as the settlement of piers and the expansion and contraction of beam bodies. For tunnels, the convergence deformation parameter can reflect the deformation of the tunnel lining under the pressure of the surrounding rock, and the pressure parameter can reflect the interaction force between the surrounding rock and the lining.

[0050] S103: Determine the sensor type and layout plan. Select sensors according to the selected monitoring parameters. Strain gauges are used to measure strain, such as resistance strain gauges, which utilize the characteristic that their resistance values change with strain to obtain strain data. Displacement sensors include linear variable differential transformers, etc., which can accurately measure the displacement changes of the structure. When arranging sensors, it is necessary to consider being able to accurately reflect the key mechanical characteristics of the structure. Install strain gauges at key positions such as the mid-span and supports of the main girders of bridges, and install displacement sensors at the tops of piers; for tunnels, install convergence deformation sensors and pressure sensors at positions such as the crown, haunches, and sidewalls of the lining.

[0051] Specifically, the specific method of sensor installation and debugging is as follows:

[0052] S201: Specific installation of sensors. Operate strictly in accordance with the installation instructions of the sensors. For strain gauges, before installation, the installation surface should be polished and cleaned to ensure a flat surface without oil stains, and then pasted with special glue. After pasting, protective measures should be taken to prevent the strain gauges from being damaged. For displacement sensors, ensure accurate installation positions and firm brackets to ensure that the sensors can accurately measure displacement changes. When installing sensors in tunnels, the complexity of the construction environment should also be considered. For example, when installing pressure sensors behind the lining, it may be necessary to reserve installation positions during the lining construction process.

[0053] S202: Sensor debugging. After installation, the sensors need to be debugged. First, perform static debugging to check whether the initial readings of the sensors are normal. For example, the initial strain readings of strain gauges should be within the allowable error range, and the initial displacement of displacement sensors should be zero. Then, perform dynamic debugging. By simulating actual load or deformation conditions, check whether the response of the sensors is sensitive and accurate. You can apply known loads or displacements and compare the measured values of the sensors with the actual values to ensure that the error is within the specified range. Then, perform dynamic debugging. By simulating actual load or deformation conditions, check whether the response of the sensors is sensitive and accurate.

[0054] Specifically, the specific method for setting up the data acquisition system is as follows:

[0055] S301: Determine the acquisition frequency and time interval. Determine the data acquisition frequency according to factors such as the traffic flow and usage environment of the bridge and tunnel. For busy bridges, the strain and displacement data may require a higher acquisition frequency, such as once per second or once per minute, to capture the instantaneous changes caused by vehicle loads. For tunnels with less traffic, the data acquisition frequency can be appropriately reduced, such as once every few minutes or once per hour for convergence deformation and pressure data. The setting of the acquisition time interval should consider being able to comprehensively reflect the state changes of the structure at different times.

[0056] S302: Establish a data storage format and database. Specifically, design a reasonable data storage format, classify and store the collected data according to information such as sensor type, installation location, and acquisition time. You can use a database management system to establish a data table structure for convenient data query, management, and analysis. For example, set a unique number for each sensor and store the data it collects in the corresponding table. The recorded data includes fields such as acquisition time and measured value.

[0057] Specifically, the specific methods for data transmission encryption and preprocessing are as follows:

[0058] S401: Select a suitable transmission method according to factors such as the geographical location, on-site environment, and data volume of the bridge and tunnel, and encrypt the data during transmission. For situations with short distances and less interference, wired transmission methods such as RS485 bus and optical fiber can be used. For some remote areas or locations where wiring is difficult, wireless transmission methods such as ZigBee, GPRS, 4G / 5G, etc. can be used. ZigBee is suitable for short-distance and low-power data transmission, while GPRS and 4G / 5G are suitable for long-distance and large-data-volume transmission.

[0059] S402: Configure the transmission equipment and network. If wired transmission is adopted, cables or optical fibers need to be laid, and corresponding signal conversion equipment should be configured to ensure that data can be correctly converted and transmitted in different transmission media. For wireless transmission, wireless transmitters and receivers should be installed, and correct communication parameters such as frequency band, transmission rate, and IP address should be set. At the same time, the stability of the transmission network should be ensured, and network redundancy and backup measures should be set to prevent data loss;

[0060] S403: Data cleaning. Remove outliers and noise from the collected data. Outliers may be caused by sensor failures, electromagnetic interference, human factors, etc. Statistical methods can be used to identify outliers, that is, if a data point deviates from the average value by more than 3 times the standard deviation, it is considered an outlier and will be removed. For noise data, filtering methods can be used for processing. For example, low-pass filtering can remove high-frequency noise and make the data smoother for subsequent analysis;

[0061] S404: Data calibration and normalization. Calibrate the data according to the calibration parameters of the sensor to ensure the accuracy of the data. Normalization processing can unify data of different magnitudes into a range for convenient comparison and analysis. Common normalization methods include min-max normalization, which maps the data to the [0,1] interval, and the calculation formula is:

[0062]

[0063] where: x is the original data, x_min is the minimum value of the data, and x_max is the maximum value of the data.

[0064] Specifically, the specific methods of data analysis and feature extraction are as follows:

[0065] S501: Structural mechanics analysis. Using the principles of structural mechanics, calculate parameters such as the internal force and stress of the structure based on the collected strain, displacement, etc. data. Taking a bridge as an example, through the bending theory of beams, the bending moment can be calculated according to the strain distribution of the beam cross-section. Combining the material properties and geometric dimensions of the structure, further analyze whether the strength of the structure meets the requirements. For a tunnel, according to the deformation and pressure data of the lining, use the theory of elasticity to calculate the internal force of the lining and evaluate its bearing capacity;

[0066] S502: Feature extraction. Extract features from the preprocessed data that can reflect the health status of the bridge and tunnel. For example, extract statistical features such as the peak value, mean value, and standard deviation of the strain. These features can reflect the stress change of the structure under the action of load. For displacement data, features such as the change rate of displacement and the cumulative displacement can be extracted. In a tunnel, features such as the change frequency of the surrounding rock pressure and the asymmetry of the convergence deformation can also be extracted to judge whether there are local diseases or uneven deformations in the structure.

[0067] Specifically, the specific methods for state evaluation and early warning are as follows:

[0068] S601: Establish an evaluation model. The analytic hierarchy process (AHP), fuzzy comprehensive evaluation method, etc. can be used to establish a bridge-tunnel health state evaluation model. The AHP stratifies the evaluation indicators, determines the weights of each indicator by constructing a judgment matrix, and then comprehensively calculates to obtain the health state score of the structure. The fuzzy comprehensive evaluation method takes into account the fuzziness of the evaluation indicators. By establishing a fuzzy relation matrix and determining the membership function, a fuzzy comprehensive evaluation of the structure health state is carried out. For example, the bridge-tunnel health state is divided into four grades: good, general, poor, and dangerous. The grade to which the structure belongs is determined according to the data analysis results and the evaluation model;

[0069] S602: Set warning thresholds and alarm mechanisms. According to the design standards, specification requirements of the structure and past engineering experience, set warning thresholds for different grades. When the monitoring data exceeds the corresponding threshold, trigger the alarm mechanism. For example, for the strain of a bridge, when the measured strain reaches 80% of the design allowable strain, a first-level warning is issued, indicating that monitoring needs to be strengthened; when it reaches the design allowable strain, a second-level warning is issued, considering restricting traffic loads; when it exceeds the design allowable strain and obvious diseases such as cracks appear, a third-level warning is issued, requiring immediate maintenance measures. The alarm methods can include various methods such as sound alarms, text message notifications, and system interface prompts to ensure that relevant personnel can receive alarm information in a timely manner.

[0070] The above-described preferred embodiments of the present invention disclosed are only used to help explain the present invention. The preferred embodiments do not elaborate on all details, nor do they limit the invention to the specific embodiments described. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art in the relevant technical field can well understand and utilize the present invention.

Claims

1. A method for monitoring the health status of bridges and tunnels, characterized in that: The specific steps of the bridge-tunnel health status monitoring method are as follows: S1: Monitoring system planning and design; S2: Sensor installation and debugging; S3: Setting up the data acquisition system; S4: Data transmission, encrypted transmission and preprocessing; S5: Data analysis and feature extraction; S6: Status evaluation and early warning.

2. The bridge-tunnel health status monitoring method according to claim 1, wherein: The specific method of the monitoring system planning and design is as follows: S101: Determine the monitoring objectives and scope, specifically the main girder, piers, abutments of the bridge-tunnel, and the lining and surrounding rock of the tunnel; S102: Select monitoring parameters. According to the structural characteristics and possible diseases of the bridge-tunnel, select appropriate monitoring parameters; S103: Determine the sensor type and layout scheme. Select sensors according to the selected monitoring parameters. Strain gauges are used to measure strain, such as resistance strain gauges, and utilize the characteristic that their resistance value changes with strain to obtain strain data.

3. The method for monitoring the health status of a bridge and tunnel according to claim 1, characterized in that: The specific method of the sensor installation and debugging is as follows: S201: Specific installation of sensors, and operate strictly in accordance with the sensor installation instructions; S202: Sensor debugging. After installation, the sensors need to be debugged. First, conduct static debugging to check whether the initial readings of the sensors are normal. Then, conduct dynamic debugging. By simulating actual load or deformation conditions, check whether the response of the sensors is sensitive and accurate.

4. A bridge-tunnel health status monitoring method according to claim 1, characterized in that: The specific method of setting up the data acquisition system is as follows: S301: Determine the acquisition frequency and time interval. Determine the data acquisition frequency according to factors such as the traffic flow and usage environment of the bridge-tunnel. The setting of the acquisition time interval should consider being able to comprehensively reflect the state changes of the structure at different times; S302: Establish a data storage format and database. Specifically, design a reasonable data storage format, classify and store the collected data according to information such as sensor type, installation location, and acquisition time. A database management system can be used to establish a data table structure to facilitate data query, management, and analysis.

5. The bridge-tunnel health status monitoring method according to claim 1, characterized in that: The specific method of the data transmission, encrypted transmission and preprocessing is as follows: S401: Select an appropriate transmission method according to factors such as the geographical location, on-site environment, and data volume of the bridge-tunnel, and encrypt the data during transmission; S402: Configure transmission equipment and networks. If wired transmission is adopted, cables or optical fibers need to be laid, and corresponding signal conversion equipment needs to be configured to ensure that data can be correctly converted and transmitted in different transmission media. For wireless transmission, install wireless transmitters and receivers, and set correct communication parameters, such as frequency band, transmission rate, IP address; S403: Data cleaning. Remove outliers and noise from the collected data. Outliers may be caused by sensor failures, electromagnetic interference, human factors, etc. Statistical methods can be used to identify outliers, that is, if a data point deviates from the average value by more than 3 times the standard deviation, it is considered an outlier and will be excluded. For noise data, filtering methods can be used for processing, such as low-pass filtering can remove high-frequency noise; S404: Data calibration and normalization. According to the calibration parameters of the sensor, the data is calibrated to ensure its accuracy. The normalization process can unify data of different magnitudes into a certain range for convenient comparison and analysis. Commonly used normalization methods include min-max normalization, which maps the data to the interval [0, 1]. The calculation formula is: where: \(x\) is the original data, \(x_{min}\) is the minimum value of the data, and \(x_{max}\) is the maximum value of the data.

6. The bridge-tunnel health status monitoring method according to claim 1, characterized in that: The specific method of data analysis and feature extraction is as follows: S501: Structural mechanics analysis. Using the principles of structural mechanics, parameters such as internal force and stress of the structure are calculated based on the collected data of strain, displacement, etc.; S502: Feature extraction. Features that can reflect the health status of the bridge and tunnel are extracted from the preprocessed data. For example, statistical features such as the peak value, mean value, and standard deviation of strain are extracted. These features can reflect the stress change of the structure under the action of load. For displacement data, features such as the change rate of displacement and the cumulative displacement can be extracted.

7. The method for monitoring the health status of a bridge and tunnel according to claim 1, characterized in that: The specific method of state evaluation and early warning is as follows: S601: Establish an evaluation model. The analytic hierarchy process (AHP), fuzzy comprehensive evaluation method, etc. can be used to establish an evaluation model for the health status of the bridge and tunnel. The AHP stratifies the evaluation indicators, determines the weights of each indicator by constructing a judgment matrix, and then comprehensively calculates the health status score of the structure. The fuzzy comprehensive evaluation method takes into account the fuzziness of the evaluation indicators, and conducts a fuzzy comprehensive evaluation of the structure health status by establishing a fuzzy relation matrix and determining the membership function; S602: Set warning thresholds and alarm mechanisms. According to the design standards, specification requirements of the structure and previous engineering experience, different levels of warning thresholds are set. When the monitoring data exceeds the corresponding threshold, the alarm mechanism is triggered. The alarm methods can include various methods such as sound alarm, SMS notification, and system interface prompt to ensure that relevant personnel can receive the alarm information in a timely manner.

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