Method for detecting interface bonding quality of steel-concrete cable tower

Abstract

The application discloses a kind of interface bonding quality detection methods of steel shell concrete cable tower, comprising: step 1, making full-scale local model, piezoelectric sensor is arranged in its straight edge, outer circular arc edge and inner circular arc edge;Step 2, select measurement point to carry out frequency sweep measurement to determine detection frequency band, determine the root mean square difference value of electromechanical coupling impedance as the evaluation index of interface bonding quality;Step 3, respectively, on straight edge, outer circular arc edge and inner circular arc edge three detection regions are independently statistically analyzed, calculate the abnormality judgment upper limit value of each region with 95% guarantee rate to determine the interface peeling defect of each detection region;Step 4, verification analysis is carried out to each region health measurement point.The detection method is partitioned independently modeling to the complex cross-sectional configuration of cable tower, effectively eliminates the influence of different boundary conditions on detection result, and the reliability of measurement data is guaranteed through verification analysis.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a method for testing the interfacial bonding quality of steel-shell concrete cable towers. Background Technology

[0002] Steel-concrete composite cable towers are a novel structural form that combines a steel shell with a core concrete structure for load-bearing. The quality of the interfacial bond between the steel shell and the concrete is crucial to ensuring their coordinated operation. If delamination defects occur at the interface, the restraining effect of the steel shell on the concrete will weaken, potentially leading to a decrease in the structure's load-bearing capacity or even causing local instability. Therefore, effective testing of the interfacial bond quality of steel-concrete composite cable towers is of significant engineering importance.

[0003] Currently, several mature technologies exist for detecting interfacial delamination defects in concrete-filled steel tubular (CFST) members. Among them, the piezoelectric impedance method involves embedding piezoelectric sensors on or inside the structure and measuring the impedance spectrum of the electromechanical coupling system formed by the sensors and the main structure. Changes in the impedance spectrum are then used to identify the interfacial bonding state. This method boasts high sensitivity and fast response, and has achieved good results in CFST members with regular cross-sections such as circles and rectangles. In addition, mature non-destructive testing techniques such as ultrasonic testing and impact-echo methods are also commonly used to detect internal defects in concrete.

[0004] However, steel-concrete composite cable towers differ significantly in construction from conventional steel-concrete composite structures. To meet complex stress requirements, the tower's interior typically incorporates numerous stiffening ribs, tie rods, and dense steel mesh. This internal complexity results in mechanical properties that differ from traditional steel-concrete composite structures, making existing testing methods difficult to directly apply. Furthermore, the complex internal structure hinders the dense filling of concrete, increasing the difficulty of achieving a good bond between the steel shell and the concrete. Therefore, it is essential to explore a testing method to accurately assess the interfacial bond quality of steel-concrete composite cable towers. Summary of the Invention

[0005] The main technical problem to be solved by the present invention is to provide a detection method that can accurately evaluate the interfacial bonding quality of steel-shell concrete cable towers.

[0006] To address the aforementioned technical problems, this invention provides a method for detecting the interfacial bonding quality of steel-shell concrete cable towers, comprising the following steps:

[0007] Step 1, this step includes:

[0008] Step 11: Fill the steel shell with concrete to create a full-scale partial model of the steel-shell concrete cable tower; the full-scale model has three inspection areas: a straight edge, an outer arc edge, and an inner arc edge.

[0009] Step 12: Set up measuring points on the outer surface of the steel shell along the straight edge, outer arc edge, and inner arc edge, and install piezoelectric sensors at the measuring points.

[0010] Step 2, this step includes:

[0011] Step 21: Apply excitation signals of different frequencies to the piezoelectric sensor at the measuring point to perform frequency sweep measurement on the impedance modulus of the electromechanical coupling system composed of the piezoelectric sensor, steel shell, and concrete, and determine the frequency band with obvious peaks and troughs in the measurement curve as the detection frequency band.

[0012] Step 22: Establish an evaluation index for the interfacial bonding quality. The evaluation index is the root mean square difference (RMSD) of the electromechanical coupling impedance, and its calculation formula is as follows:

[0013] ; ①

[0014] in, This indicates the number of frequency points taken within the detection frequency band. Indicates the first within the detection frequency band Each frequency point, Indicates the piezoelectric sensor at the first Impedance measurements at each frequency point Indicates the piezoelectric sensor at the first Impedance reference value at each frequency point;

[0015] Step 3: Measure the electromechanical coupling impedance of all measuring points, and perform independent statistical analysis and anomaly judgment on the measured values ​​of the three detection areas: straight edge, outer arc edge, and inner arc edge. For each detection area, the statistical analysis and anomaly judgment include:

[0016] Step 31: Select the electromechanical coupling impedance value of the measuring point with a smooth impedance curve without obvious fluctuations and good fit as the impedance reference value, and calculate the evaluation index of the remaining measuring points in the detection area relative to the impedance reference value.

[0017] Step 32: Perform statistical analysis on the evaluation indicators of each measuring point in the detection area, and calculate the upper limit value for anomaly judgment in the detection area based on a 95% guarantee rate;

[0018] Step 33: Compare the evaluation index of each measuring point in the detection area with the upper limit value of anomaly judgment to determine whether there is an interface peeling defect at the measuring point;

[0019] Step 4: Perform verification analysis on the healthy measurement points in the three detection areas: straight edge, outer arc edge, and inner arc edge. The healthy measurement points refer to the measurement points that were not determined to have interface peeling defects in Step 3. For each detection area, the verification analysis includes: using the average impedance of all healthy measurement points in the detection area as the impedance reference value, recalculating the evaluation index of each healthy measurement point according to formula ①, and then evaluating whether the evaluation index of each healthy measurement point is within the preset range.

[0020] In a preferred embodiment, in step 32, the method for calculating the upper limit of anomaly judgment for a detection area is as follows:

[0021] Step 321: Arrange the RMSD values ​​of all measuring points within the detection area as follows: The first RMSD value in the series to show a significant increase. The dataset consists of all RMSDs listed before it. ;

[0022] Step 322: Calculate the upper limit of anomaly detection for the computational dataset according to formula ②. :

[0023] ; ②

[0024] in, , The mean and standard deviation of the dataset are respectively calculated. The statistical coefficient is taken as 1.65 when the number of measurement points is less than or equal to 20.

[0025] In a preferred embodiment, the full-scale partial model is L-shaped with rounded corners, and its straight sides include a long straight side and a short straight side provided on the outer surface of the steel shell.

[0026] In a preferred embodiment, in step 12, measurement points are set up separately for the two detection areas of the long straight edge and the short straight edge; in step 31, the evaluation index of the internal measurement points of the two detection areas of the long straight edge and the short straight edge is calculated separately; in step 32, the measurement points of the two detection areas of the long straight edge and the short straight edge are combined together to calculate the upper limit value of the anomaly judgment.

[0027] In a preferred embodiment, in step 4, the health measurement points within the two detection areas of the long straight edge and the short straight edge are combined together for confirmatory analysis.

[0028] In a preferred embodiment, in step 4, for the same detection area, the confirmatory analysis further includes: observing the dispersion of the electromechanical coupling impedance curves of all measuring points within the detection area.

[0029] In a preferred embodiment, in step 21, the detection frequency band is 100kHz to 600kHz.

[0030] In a preferred embodiment, in step 4, the preset interval is [0, 10%].

[0031] In a preferred embodiment, in step 11, the full-scale model is a 1 / 4 cross-sectional model of a standard construction segment of the steel-shell concrete cable tower.

[0032] In a preferred embodiment, the piezoelectric sensor is a piezoelectric ceramic sheet.

[0033] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0034] (1) For the complex cross-sectional shape of the steel-concrete cable tower, the detection area is divided into straight edge, outer arc edge and inner arc edge. The impedance benchmark value of each area is selected independently and the upper limit value of the anomaly judgment is calculated. This effectively eliminates the interference of different boundary conditions and curvature characteristics on the accuracy of electromechanical coupling impedance value analysis and significantly improves the identification accuracy of interface peeling defects. (2) Through the verification analysis in step 4, the evaluation index is recalculated based on the average impedance of all healthy measuring points in each detection area to ensure that the electromechanical coupling impedance value of healthy measuring points is within the preset range. At the same time, the dispersion of the impedance curve is observed, which effectively verifies the reliability of the detection data and the rationality of the evaluation benchmark. (3) The detection is carried out using a full-scale local model, which realistically simulates the structural characteristics and constraint boundaries of the actual cable tower, making the detection results more valuable for engineering reference and able to directly guide the on-site construction quality assessment. Attached Figure Description

[0035] Figure 1 This is a top view of the full-scale partial model described in an embodiment of the present invention;

[0036] Figure 2 This is a diagram showing the layout of measuring points for the full-scale local model described in this embodiment of the invention.

[0037] Figure 3 This is the impedance curve used when selecting the detection frequency band in this embodiment of the invention;

[0038] Figure 4 This is an impedance curve diagram of each measuring point on the long straight side described in this embodiment of the invention;

[0039] Figure 5 This is a bar chart showing the evaluation index of each measuring point on the long straight side in the embodiments of the present invention;

[0040] Figure 6 This is an impedance curve diagram of each measuring point on the short straight side described in this embodiment of the invention;

[0041] Figure 7 This is a bar chart showing the evaluation index of each measuring point on the short straight edge in the embodiments of the present invention;

[0042] Figure 8 This is an impedance curve diagram of each measuring point on the outer arc edge described in this embodiment of the invention;

[0043] Figure 9 This is a bar chart showing the evaluation indicators for each measuring point on the outer arc edge in this embodiment of the invention.

[0044] Figure 10 This is an impedance curve diagram of each measuring point on the inner arc edge described in this embodiment of the invention;

[0045] Figure 11 This is a bar chart showing the evaluation index of each measuring point on the inner arc edge in the embodiments of the present invention;

[0046] Figure 12 This is an impedance curve diagram of each healthy measurement point on the straight side as described in this embodiment of the invention;

[0047] Figure 13 This is a bar chart showing the evaluation indicators for each health measurement point on the straight edge as described in this embodiment of the invention.

[0048] Figure 14 This is an impedance curve diagram of each healthy measuring point on the outer arc edge described in this embodiment of the invention;

[0049] Figure 15 This is a bar chart showing the evaluation indicators for each health measurement point on the outer arc edge as described in this embodiment of the invention.

[0050] Figure 16 This is an impedance curve diagram of each healthy measuring point on the inner arc edge as described in this embodiment of the invention;

[0051] Figure 17 This is a bar chart showing the evaluation indicators for each health measurement point on the inner arc edge in this embodiment of the invention.

[0052] Figure 1 The labels are: 11-long straight edge, 12-short straight edge, 3-outer circular arc edge, 4-inner circular arc edge. Detailed Implementation

[0053] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0054] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed", "equipped", "sleeved / connected", "connected", etc., should be interpreted broadly. For example, "connection" can be a wall-mounted connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0056] like Figures 1 to 17 As shown, this invention provides a method for detecting the interface bonding quality of steel-concrete composite cable towers, using the Liuwudian Channel Bridge of the Third East Channel in Xiamen as an engineering example. The method generally includes the following steps: S1, creating a model and arranging measuring points; S2, selecting a detection frequency band and establishing evaluation indicators; S3, detecting the interface bonding quality in different regions; and S4, verifying the consistency of healthy measuring points. Each step will be described in detail below.

[0057] S1, Create a physical model and deploy sensors. This step includes:

[0058] S11, Create a full-scale partial model

[0059] A full-scale partial model of a steel-shell concrete cable-stayed tower was constructed. This full-scale partial model is a scaled-down local structural model based on the actual structure of a segment of the tower's steel shell, used to simulate the internal structural features and constraint boundaries of the steel shell. For example... Figure 1 As shown, the full-scale partial model is a 1 / 4 section model of a standard construction segment of the cable tower. It is generally L-shaped with rounded corners, with the following dimensions: total length 4.5m, total width 3.15m, spacing between inner and outer wall panels 1.2m, corner radius 1.2m, and vertical height 2.0m. The model's interior is arranged with vertical stiffening ribs, horizontal stiffening ribs, and tie angle steel as designed, and acrylic observation windows are provided on the sides for monitoring the concrete filling process.

[0060] S12, Install piezoelectric sensors

[0061] Since most steel-shell concrete cable towers are not regular cylinders, the boundary conditions, curvature characteristics, and structural dynamic responses vary at different cross-sectional locations. For example, the cable tower simulated by the full-scale local model in this embodiment exhibits different mechanical properties at its wide side, long side, and rounded corners. Therefore, this embodiment divides the detection area into straight edges, outer circular arc edges 2, and inner circular arc edges 3 according to geometric features and boundary conditions. The straight edges are further divided into long straight edges 11 and short straight edges 12. Then, independent benchmark selection, statistical analysis, and anomaly judgment are performed for each of these four detection areas. Furthermore, to further verify the rationality of the detection method and the reliability of the measurement results, this embodiment also performs confirmatory analysis on healthy measurement points in each detection area that are judged not to have interface delamination.

[0062] Considering the feasibility and convenience of practical engineering applications, this embodiment uses piezoelectric sensors attached to the outer wall of the steel shell to detect the interface bonding quality. The piezoelectric sensors are preferably piezoelectric ceramic sheets. Specifically, three, two, two, and two columns of measuring points are respectively arranged on the long straight side 11, short straight side 12, outer arc side 2, and inner arc side 3, for a total of nine columns of measuring points. Each column has four measuring points spaced apart along the height direction. A set of piezoelectric sensors is attached to each measuring point. The piezoelectric sensor is numbered using two digits: the first digit represents the column number, and the second digit represents the height number. The height numbers are 1, 2, 3, and 4 from top to bottom, separated by a dot. Figure 2 As shown. Since piezoelectric sensors are not placed in the observation windows of the acrylic plates at measuring points 1.2 and 1.3, a total of 34 sets of piezoelectric sensors are arranged.

[0063] S2, Determine the evaluation methods and standards. This step includes:

[0064] S21, Select the detection frequency band

[0065] Under high-frequency electrical excitation, the impedance curve reflects the vibration characteristics of the electromechanical coupling system between the piezoelectric sensor and the main structure. Bond defects between the concrete and steel shell sections can cause changes in the vibration characteristics of the electromechanical coupling system, thereby causing shifts and changes in the peak point of the impedance characteristic curve.

[0066] The electromechanical coupling impedance of a piezoelectric ceramic sheet is significantly related to its excitation frequency. To assess the interfacial bond quality between the steel shell and concrete in this experiment, a suitable frequency band must be selected—specifically, the band where the electromechanical coupling impedance curve shows peaks and troughs. This allows the changes in the frequency corresponding to the peaks and troughs of the impedance curve to reflect changes in the interfacial bond quality between the steel shell and concrete. Therefore, three measuring points were randomly selected from all measuring points on the specimen for electromechanical coupling impedance measurements. The pattern of the electromechanical coupling impedance measurement curve was observed, and the detection frequency band was selected for electromechanical coupling impedance measurement. Figure 3It can be seen that the electromechanical coupling impedance measurement curves at the measuring points exhibit obvious peaks and troughs within the 100kHz-600kHz frequency range, which can be used as the detection frequency range for subsequent interfacial bonding quality assessment. In the following field measurements, the electromechanical coupling impedance of the piezoelectric sensor at each measuring point within the 100kHz-600kHz detection frequency range was measured. The evaluation index values ​​of the electromechanical coupling impedance measurements at each measuring point were calculated and analyzed. Abnormal values ​​of the evaluation index for interfacial bonding quality at each measuring point were analyzed, and the interfacial delamination points were subsequently identified. When performing electromechanical coupling impedance measurements, the number of sampling points within the detection frequency range was 1600.

[0067] S22, Establish evaluation indicators

[0068] Based on the testing principle of the piezoresistive impedance method, this embodiment uses the root mean square difference of electromechanical coupling impedance (hereinafter referred to as "RMSD") as an evaluation index to assess the interfacial bonding quality of the tested steel-shell concrete cable tower. The calculation formula is as follows:

[0069] ; ①

[0070] in, This indicates the number of frequency points taken within the detection frequency band. Indicates the first within the detection frequency band Each frequency point, Indicates the piezoelectric sensor at the first Impedance measurements at each frequency point Indicates the piezoelectric sensor at the first Impedance reference value at each frequency point.

[0071] S23, Method for judging abnormal interfacial bonding quality

[0072] To determine anomalies in the bonding quality at the measuring points, outlier analysis was performed on the RMSD (Mechanical Relationship Degradation Score) of the electromechanical coupling impedance measurements at each measuring point. The upper limit for anomaly judgment was obtained by statistically analyzing the RMSD of all measuring points within a testing area and selecting a threshold value with a 95% guarantee rate. When the RMSD value of a measuring point is greater than the upper limit for anomaly judgment, the electromechanical coupling impedance value at that measuring point is considered to differ significantly from the electromechanical coupling impedance value when no delamination occurs, indicating a delamination between the concrete and the steel shell at that measuring point. When the RMSD value of a measuring point is less than the upper limit for anomaly judgment, the concrete and steel shell at that measuring point are considered not to have delamination. When the evaluation index of a measuring point is close to but not greater than the aforementioned upper limit for anomaly judgment, the measuring point is identified as a suspected delamination point, and its electromechanical coupling impedance value needs to be remeasured and re-evaluated.

[0073] The calculation method for the upper limit of anomaly detection in a detection area is as follows:

[0074] S231, arrange the RMSD values ​​of all measuring points in the detection area as follows: The first RMSD value in the series to show a significant increase. The dataset consists of all RMSDs listed before it. ;

[0075] S232, calculate the upper limit value for anomaly detection of the computational dataset according to formula ②. :

[0076] ; ②

[0077] in, , The mean and standard deviation of the dataset are respectively calculated. These are statistical coefficients taken according to the specifications. According to Table 6.3.2 of the "Technical Specification for Ultrasonic Testing of Concrete Defects" (CECS-2000), the value should be 1.65 when the number of measuring points is less than or equal to 20.

[0078] S3, Regional detection of interface adhesion quality

[0079] The electromechanical coupling impedance values ​​at all measuring points were measured. Following the evaluation methods and standards determined in S2, independent statistical analysis and anomaly judgment were performed on the three types of detection areas: straight edge, outer arc edge 2, and inner arc edge 3. For each detection area, the statistical analysis and anomaly judgment included:

[0080] S31: Select the electromechanical coupling impedance value of the measuring point with a smooth impedance curve, no obvious fluctuations, and good fit as the impedance reference value, and calculate the evaluation index of the remaining measuring points in the detection area relative to the impedance reference value.

[0081] S32: Perform statistical analysis on the evaluation indicators of each measuring point in the detection area, and calculate the upper limit of the anomaly judgment value of the detection area based on a 95% guarantee rate.

[0082] S33: Compare the evaluation index of each measuring point in the detection area with the upper limit value of the anomaly judgment to determine whether there is an interface peeling defect at the measuring point.

[0083] The following section provides further explanation of the above steps in conjunction with the various testing areas.

[0084] (1) Analysis of straight edge detection area

[0085] The straight-edge region includes three columns of measuring points on the long straight edge 11 and two columns of measuring points on the short straight edge 12. In this embodiment, the evaluation indicators of the measuring points within the two detection regions of the long straight edge 11 and the short straight edge 12 are calculated separately, but they are combined to calculate the overall upper limit value for anomaly judgment. Figure 4 For the long straight side 11, the impedance curve at measuring point 1.1 is smooth with no obvious fluctuations and good agreement. Therefore, its impedance value is used as the impedance reference value to calculate the RMSD of each measuring point; Figure 6 For the short straight side 12, the impedance value of measuring point 6.2 is used as the impedance reference value to calculate the evaluation index value of each measuring point. According to equation ②, the upper limit of the anomaly judgment value of the straight side region with a 95% guarantee rate is 10.86%.

[0086] The evaluation indicators for each measuring point in the detection area are compared with the upper limit value for anomaly judgment. For example... Figure 5 The RMSD values ​​of all 10 measuring points on the long straight side 11 were less than 10.86%, indicating that no obvious delamination of the bond interface between the steel shell and the core concrete was observed at any of the measuring points on the long straight side 11. However, the RMSD value at measuring point 3.4 was relatively high, suggesting it might be a suspected area. Figure 7 Among all the measuring points on the short straight edge 12, the RMSD value of measuring point 7.1 is greater than the judgment value of 10.86%, which indicates that there is obvious delamination at the bonding interface between the steel shell and the core concrete at measuring point 7.1. No obvious delamination is observed at the other measuring points. The RMSD value at measuring point 6.1 is close to the abnormal value, which is suspected to be peeling.

[0087] (2) Analysis of the detection area of ​​the outer arc edge

[0088] Because the curvature direction of the inner arc edge 3 is opposite to that of the outer arc edge 2, and it is affected by internal constraints, its structural dynamic response characteristics are different from those of the outer arc edge 2 and the straight edge. Therefore, they are analyzed statistically independently. There are a total of 8 measuring points in two columns for the outer arc edge 2. For example... Figure 8 The impedance curves of measuring points 4.3 and 5.2 are smooth with no obvious fluctuations and good agreement. Therefore, the average impedance of these two measuring points is used as the impedance benchmark value to calculate the evaluation index value of each measuring point. According to equation ②, the upper limit of anomaly judgment for the outer arc edge 2 detection area is 10.39% under the condition of 95% guarantee rate.

[0089] like Figure 9 By comparing the evaluation indicators of each measuring point in the detection area with the upper limit of anomaly judgment, the RMSD values ​​of all 8 measuring points on the outer arc edge 2 were less than 10.39%, and no obvious delamination phenomenon was found at the bonding interface between the steel shell and the core concrete. Since the RMSD values ​​at measuring points 4.1, 4.2, and 5.1 were relatively large, they can be considered as suspected areas.

[0090] (3) Analysis of the detection area of ​​the inner arc edge

[0091] There are a total of 8 measuring points in two columns along the inner arc edge. For example... Figure 10 The impedance curves of measuring point 8.1 are all smooth with no obvious fluctuations and good agreement. Using its impedance value as the impedance benchmark, the evaluation index values ​​for each measuring point are calculated. According to equation ②, the upper limit for anomaly judgment in the inner arc edge detection area, with a 95% guarantee rate, is 16.68%.

[0092] like Figure 11 By comparing the evaluation index of each measuring point in the detection area with the upper limit of the anomaly judgment value, it was found that the RMSD value of measuring point 8.4 was greater than the anomaly judgment value. It can be judged that under the condition of 95% guarantee rate, the bonding interface between the steel shell and the core concrete at measuring point 8.4 of the inner arc edge 3 has a voiding phenomenon. No obvious voiding phenomenon was found at the other measuring points. The RMSD value at measuring point 9.3 is close to the anomaly value, and peeling is suspected.

[0093] To ensure the reliability of the test results, for measurement points 8.4 and 9.3, where the impedance curves differed significantly from other measurement points during the first measurement, the piezoelectric ceramic sheets were reattached and measurements were performed again. The results from both measurements were consistent. Figure 10 In the middle, (1) and (2) after the measuring point represent the first and second measurements respectively. It can be seen that the measuring points 8.4 and 9.3 are likely to peel off.

[0094] S4, Regional confirmatory analysis

[0095] Verification retests were performed on the healthy measurement points in the three detection areas: straight edge, outer arc edge 2, and inner arc edge 3. The healthy measurement points refer to those not identified as having interface peeling defects in S3. For each detection area, the verification retest included: using the average impedance of all healthy measurement points in that detection area as the impedance benchmark value, recalculating the evaluation index of each healthy measurement point according to formula ①, and then evaluating whether the evaluation index of each healthy measurement point was within a preset range. In this embodiment, the preset range is [0, 10%].

[0096] Taking the straight-edge detection area as an example, the electromechanical coupling impedance measurements of all healthy measuring points on the long straight edge 11 and the short straight edge 12 are compared and analyzed. The average impedance of all healthy measuring points within this detection area is used as the impedance reference value. Recalculate the RMSD value for each health measurement point according to formula ①. Figure 13 As can be seen, the RMSD values ​​of all healthy measurement points are less than 8%, indicating that the electromechanical coupling impedance measurements at each point are reliable. Taking the outer arc edge detection area as an example, the average impedance of all healthy measurement points within this detection area is used as the impedance reference value. Recalculate the RMSD value for each health measurement point according to formula ①. Figure 15As can be seen, the RMSD values ​​of all health measurement points are less than 8%, indicating that the electromechanical coupling impedance measurements at each point are reliable. Taking the inner arc edge detection area as an example, from... Figure 17 It is evident that the RMSD values ​​of all health measurement points are less than 8%, indicating that the electromechanical coupling impedance measurements at each measurement point are reliable.

[0097] In addition, for the same detection area, besides numerical analysis, the confirmatory retest also includes observing the dispersion of the electromechanical coupling impedance curves of all measuring points within that detection area. Figure 12 , Figure 14 and Figure 16 It is easy to see that the impedance curves of each measuring point in the above three detection areas have low dispersion, and their measured values ​​are reliable.

[0098] In summary, the detection method provided in this embodiment of the invention addresses the complex cross-sectional shape of steel-concrete cable towers by dividing the detection area into straight edges, outer circular arc edges, and inner circular arc edges. Each area independently selects an impedance benchmark value and calculates anomaly judgment upper limit values, effectively eliminating the interference of different boundary conditions and curvature characteristics on the accuracy of electromechanical coupling impedance value analysis, and significantly improving the accuracy of identifying interface peeling defects. Secondly, through the verification analysis in step 4, the detection method recalculates the evaluation index using the average impedance of all healthy measuring points in each detection area, ensuring that the electromechanical coupling impedance values ​​of healthy measuring points are within a preset range. Simultaneously, the dispersion of the impedance curve is observed, effectively verifying the reliability of the detection data and the rationality of the evaluation benchmark. Furthermore, the detection method uses a full-scale local model for detection, realistically simulating the structural characteristics and constraint boundaries of the actual cable tower, making the detection results more valuable for engineering reference and directly guiding on-site construction quality assessment.

[0099] The above description is merely a preferred embodiment of the present invention and is not intended to limit the patent scope of the present invention. Any technically equivalent modifications made based on the content of this specification shall fall within the protection scope of the present invention.

Claims

1. A method for detecting the interfacial bonding quality of a steel-shell concrete cable tower, characterized in that: Includes the following steps: Step 1, this step includes: Step 11: Fill the steel shell with concrete to create a full-scale partial model of the steel-shell concrete cable tower; the full-scale model has three inspection areas: a straight edge, an outer arc edge, and an inner arc edge. Step 12: Set up measuring points on the outer surface of the steel shell along the straight edge, outer arc edge, and inner arc edge, and install piezoelectric sensors at the measuring points. Step 2, this step includes: Step 21: Apply excitation signals of different frequencies to the piezoelectric sensor at the measuring point to perform frequency sweep measurement on the impedance modulus of the electromechanical coupling system composed of the piezoelectric sensor, steel shell, and concrete, and determine the frequency band with obvious peaks and troughs in the measurement curve as the detection frequency band. Step 22: Establish an evaluation index for the interfacial bonding quality. The evaluation index is the root mean square difference (RMSD) of the electromechanical coupling impedance, and its calculation formula is as follows: ； ① in, This indicates the number of frequency points taken within the detection frequency band. Indicates the first within the detection frequency band Each frequency point, Indicates the piezoelectric sensor at the first Impedance measurements at each frequency point Indicates the piezoelectric sensor at the first Impedance reference value at each frequency point; Step 3: Measure the electromechanical coupling impedance of all measuring points, and perform independent statistical analysis and anomaly judgment on the measured values ​​of the three detection areas: straight edge, outer arc edge, and inner arc edge. For each detection area, the statistical analysis and anomaly judgment include: Step 31: Select the electromechanical coupling impedance value of the measuring point with a smooth impedance curve without obvious fluctuations and good fit as the impedance reference value, and calculate the evaluation index of the remaining measuring points in the detection area relative to the impedance reference value. Step 32: Perform statistical analysis on the evaluation indicators of each measuring point in the detection area, and calculate the upper limit value for anomaly judgment in the detection area based on a 95% guarantee rate; Step 33: Compare the evaluation index of each measuring point in the detection area with the upper limit value of anomaly judgment to determine whether there is an interface peeling defect at the measuring point; Step 4: Perform verification analysis on the healthy measurement points in the three detection areas: straight edge, outer arc edge, and inner arc edge. The healthy measurement points refer to the measurement points that were not determined to have interface peeling defects in Step 3. For each detection area, the verification analysis includes: using the average impedance of all healthy measurement points in the detection area as the impedance reference value, recalculating the evaluation index of each healthy measurement point according to formula ①, and then evaluating whether the evaluation index of each healthy measurement point is within the preset range.

2. The method for detecting the interfacial bonding quality of a steel-shell concrete cable tower according to claim 1, characterized in that: In step 32, the calculation method for the upper limit of anomaly judgment for a detection area is as follows: Step 321: Arrange the RMSD values ​​of all measuring points within the detection area as follows: The first RMSD value in the series to show a significant increase. The dataset consists of all RMSDs listed before it. ; Step 322: Calculate the upper limit of anomaly detection for the computational dataset according to formula ②. : ； ② in, , The mean and standard deviation of the dataset are respectively calculated. The statistical coefficient is taken as 1.65 when the number of measurement points is less than or equal to 20.

3. The method for detecting the interfacial bonding quality of a steel-shell concrete cable tower according to claim 1, characterized in that: The straight edges of the full-scale local model include a long straight edge and a short straight edge located on the outer surface of the steel shell.

4. The method for detecting the interfacial bonding quality of a steel-shell concrete cable tower according to claim 3, characterized in that: In step 12, measurement points are set up separately for the two detection areas, the long straight edge and the short straight edge; In step 31, the evaluation index of the internal test points of the two detection regions, the long straight edge and the short straight edge, is calculated separately; in step 32, the test points of the two detection regions, the long straight edge and the short straight edge, are merged together to calculate the upper limit value of the anomaly judgment.

5. The method for detecting the interfacial bonding quality of a steel-shell concrete cable tower according to claim 4, characterized in that: In step 4, the health measurement points within the two detection areas, the long straight edge and the short straight edge, are combined together for confirmatory analysis.

6. The method for detecting the interfacial bonding quality of a steel-shell concrete cable tower according to claim 1, characterized in that: In step 4, for the same detection area, the confirmatory analysis also includes: observing the dispersion of the electromechanical coupling impedance curves of all measuring points within the detection area.

7. The method for detecting the interfacial bonding quality of a steel-shell concrete cable tower according to claim 1, characterized in that: In step 21, the detection frequency band is from 100kHz to 600kHz.

8. The method for detecting the interfacial bonding quality of a steel-shell concrete cable tower according to claim 1, characterized in that: In step 4, the preset interval is [0, 8%].

9. The method for detecting the interfacial bonding quality of a steel-shell concrete cable tower according to claim 1, characterized in that: In step 11, the full-scale model is a 1 / 4 section model of the standard construction segment of the steel-shell concrete cable tower.

10. The method for detecting the interfacial bonding quality of a steel-shell concrete cable tower according to claim 1, characterized in that: The piezoelectric sensor is a piezoelectric ceramic sheet.

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