A method for evaluating corrosion of a power transmission tower foot

Abstract

The application discloses a power transmission tower foot corrosion evaluation method, which comprises the following steps: establishing a tower foot corrosion degree evaluation index according to the corrosion characteristics of a power transmission tower foot, wherein the tower foot corrosion degree evaluation index comprises three first-level indexes, specifically, an appearance quality evaluation index, a corrosion risk evaluation index and a corrosion state evaluation index; judging whether to perform corrosion risk evaluation and corrosion state evaluation according to the appearance quality evaluation index of the power transmission tower foot to be evaluated; and performing corresponding maintenance operation according to the corrosion risk evaluation and the corrosion state evaluation; the first-level indexes comprise multiple second-level indexes, the evaluation is performed according to the multiple indexes, individual index is avoided to one-sidedly affect the overall evaluation result, and the result of the corrosion condition detection and evaluation is more systematic, comprehensive and reasonable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission of power grid equipment, and mainly relates to a power transmission tower foot corrosion evaluation method. BACKGROUND

[0002] The power transmission line tower and metal frame mainly play a role in supporting the power transmission line or power grid equipment in the power grid, are widely distributed in various environments, and tower foot corrosion is the key and difficulty among all corrosion problems of the power transmission tower. The corrosion has the following particularities: 1) the corrosion environment is complex and harsh, and the tower foot part is prone to oxygen concentration difference corrosion and crevice corrosion, and if the quality of the protective cap is poor, the corrosion will be aggravated due to water penetration or surface water of the protective cap; 2) the corrosion is hidden, the tower foot is wrapped in the protective cap, the internal corrosion form and corrosion degree cannot be directly observed, and is easy to be ignored to cause hidden corrosion development and deterioration, and at present, if the tower foot state in the protective cap is checked, the protective cap must be chiseled, which is time-consuming and laborious, and the cost of manpower and material resources is high; 3) the corrosion prevention work is difficult, unlike the corrosion prevention of other parts of the tower, there is no systematic mature scheme for the corrosion prevention of the tower foot in the protective cap at present, and the commonly used way is only to replace the tower foot when serious corrosion is found, and there is lack of an early prevention treatment scheme; 4) the corrosion has great harm, the tower foot is a load-bearing component of the tower, and once serious corrosion thinning occurs, the tower will be insufficient in load bearing or uneven in stress, and is easy to collapse under external forces such as strong wind and tower icing, causing the whole line failure of the power transmission line, and thus, it is necessary to timely grasp the deterioration degree of the protective cap and intervene in the deteriorated protective cap in advance to prolong the service life of the tower foot and reduce the maintenance cost.

[0003] CN103091241B "Coastal area transmission line hardware corrosion life prediction method" discloses "a kind of coastal area transmission line hardware corrosion life prediction method, the method includes the following steps: (1), from the hardware of transmission line replacement sample;(2), connect a copper wire, epoxy resin packaging;(3), clean the outer surface of sample;(4), calculate the annual average of local rainwater chloride ion content;(5), prepare simulated salt fog solution;(6), put into three-electrode system electrolytic cell test;(7), draw up dynamic potential polarization curve;(8), test obtains simulated salt fog corrosion current density;(9), obtain annual average rainfall days;10), calculate the average corrosion depth rate of medium and long term;(11), measure the average value of galvanized layer thickness;(12), obtain the remaining corrosion life of galvanized layer.This method breaks the traditional constraints, to measure the galvanized thickness of hardware surface realizes the evaluation of corrosion speed and life of hardware of transmission line in coastal area, fast and accurate, strong practicality", but industry people know that the corrosion resistance of the coating is not only determined by the thickness of the zinc layer, but also related to many parameters such as adhesion, and the relevant national standards and industry standards also require detection of multiple parameters to determine the corrosion resistance of the coating. If the corrosion resistance of the coating is determined only by the thickness of the zinc layer, we can completely thicken the zinc plating, but in fact it is far from that. Therefore, although the above evaluation method is feasible, it is too simple, the evaluation index is single, and the evaluation error is large. SUMMARY

[0004] In order to solve the above problems existing in the prior art, the application provides a transmission tower tower foot corrosion evaluation method.

[0005] The technical scheme of the application is as follows:

[0006] A transmission tower tower foot corrosion evaluation method, comprising the following steps:

[0007] Step 1: establishing a tower foot corrosion degree evaluation index according to the corrosion characteristics of the transmission tower tower foot, wherein the tower foot corrosion degree evaluation index includes three first-level indexes, specifically an appearance quality evaluation index, a corrosion risk evaluation index and a corrosion state evaluation index; Wherein the appearance quality evaluation index includes three second-level indexes, specifically rust at the junction of the tower foot and the protective cap, rust expansion crack of the protective cap and concrete weathering condition; The corrosion risk evaluation index includes five second-level indexes, specifically concrete strength degradation intensity, concrete sound velocity, concrete resistivity, corrosion potential and current density; The corrosion state evaluation index is the corrosion condition of tower foot steel, including two second-level indexes, specifically corrosion area and corrosion depth;

[0008] Step 2: obtaining the appearance quality evaluation index of the tower foot of the power transmission tower to be evaluated by the macroscopic detection method, judging whether to perform the corrosion risk assessment and the corrosion state assessment according to the appearance quality evaluation index of the tower foot of the power transmission tower to be evaluated, if the corrosion risk assessment is performed, performing step 3, if the corrosion state assessment is performed, performing step 4;

[0009] Step 3: obtaining the corrosion risk evaluation index of the tower foot of the power transmission tower to be evaluated by performing the corrosion risk assessment, and performing the corresponding maintenance operation according to the corrosion risk evaluation index of the tower foot of the power transmission tower to be evaluated;

[0010] Step 4: obtaining the corrosion state evaluation index of the tower foot of the power transmission tower to be evaluated by performing the corrosion state assessment, and performing the corresponding maintenance operation according to the corrosion state evaluation index of the tower foot of the power transmission tower to be evaluated.

[0011] Preferably, judging whether to perform the corrosion risk assessment and the corrosion state assessment according to the appearance quality evaluation index of the tower foot of the power transmission tower to be evaluated specifically comprises:

[0012] The quantitative detection results of the three secondary indexes included in the appearance quality evaluation index of the tower foot of the power transmission tower to be evaluated are obtained by the macroscopic detection method, the appearance quality evaluation index value is calculated according to the quantitative detection results of the secondary indexes and the corresponding weights, the preset appearance evaluation index value corresponds to the grade, whether to perform the corrosion risk assessment and the corrosion state assessment is judged according to the appearance quality evaluation index value corresponding to the grade, the quantitative detection result is specifically that if there is a defect corresponding to the secondary index name, the value is 1, otherwise, it is 0; the appearance quality evaluation index is expressed by a formula as follows:

[0013]

[0014] In the formula, A is the appearance quality evaluation index, A i is the secondary index of the i-th appearance quality evaluation index.

[0015] Preferably, the appearance quality evaluation index value corresponding to the grade includes appearance good, appearance with rust risk and appearance already rusted, if the corresponding grade is the appearance good state, no processing is needed; if the corresponding grade is the appearance with rust risk state, the corrosion risk assessment is performed; if the corresponding grade is the appearance already rusted, the corrosion state assessment is performed;

[0016] Preferably, the corrosion risk evaluation index of the tower foot of the power transmission tower to be evaluated obtained by performing the corrosion risk assessment specifically comprises:

[0017] The concrete strength degradation degree and the sound speed are obtained by the ultrasonic-rebound method detection; the concrete resistivity is obtained by the four-electrode method detection, the corrosion potential is obtained by the steel bar corrosion detector detection; the current density is obtained by the linear polarization method; the threshold range of the five secondary indexes is preset, the corresponding quantitative value exists in the threshold range, the detection values of the five secondary indexes are divided into the corresponding threshold range, the corresponding quantitative value is obtained, and the corrosion risk evaluation index is calculated according to the corresponding quantitative value and the secondary index corresponding weight;

[0018] Preferably, the concrete strength degradation degree and the sound speed obtained by the ultrasonic-rebound method detection are specifically:

[0019] The ultrasonic instrument is used to emit ultrasonic waves on the surface of the selected measurement area of the standard transmission tower foot structure concrete, and the standard sound time value is recorded, the rebound value is obtained by using the rebound instrument to measure the same measurement area, and the relationship curve of the standard sound time value and the rebound value is established by pairing the standard sound time value and the rebound value, the relationship curve is used as a standard sample, the ultrasonic instrument is used to emit ultrasonic waves to obtain the sound time value and the sound speed of the transmission tower foot structure concrete to be evaluated, and the sound time value of the transmission tower foot structure concrete to be evaluated is compared with the sound time value in the standard sample to obtain the concrete strength degradation degree;

[0020] Preferably, the corrosion risk evaluation index is calculated according to the corresponding quantitative value and the secondary index corresponding weight, and is expressed by a formula as:

[0021]

[0022] In the formula, B is the corrosion risk evaluation index, B i is the secondary index corresponding quantitative value of the i-th corrosion risk evaluation index, ω i is the secondary index corresponding weight of the i-th corrosion risk evaluation index;

[0023] Preferably, the risk assessment is performed according to the corrosion risk evaluation index, and the corresponding maintenance operation is specifically:

[0024] The corrosion risk evaluation grade is preset, the corresponding evaluation grade is divided according to the corrosion risk evaluation index value, the evaluation grade includes the low corrosion risk level, the medium corrosion risk level and the high corrosion risk level, if the evaluation grade is the low corrosion risk level, the transmission tower foot does not need to be processed; if the evaluation grade is the medium corrosion risk level, the area is strengthened to be patrolled; if the evaluation grade is the high corrosion risk level, the corrosion state is evaluated;

[0025] Preferably, the state evaluation is performed according to the quantitative detection result of the secondary index of the corrosion state evaluation index, and the corresponding maintenance operation is specifically:

[0026] If the corrosion area is surface without rust product, the corrosion depth detection is not needed and the tower foot does not need to be treated;

[0027] If the corrosion area is surface with rust product, the corrosion depth detection is needed;

[0028] If the corrosion depth is 0% to less than 5%, the corrosion state is evaluated as slight, the tower foot is subjected to anti-corrosion operation and the protection cap is reconstructed;

[0029] If the corrosion depth is 5% to less than 20%, the corrosion state is evaluated as moderate, the tower foot is subjected to reinforcement operation and the protection cap is reconstructed;

[0030] If the corrosion depth is 20% or more, the corrosion state is evaluated as serious, the tower foot is replaced and the protection cap is reconstructed.

[0031] Compared with the prior art, the present application has the following beneficial effects:

[0032] The present application provides a transmission tower foot corrosion evaluation method, which establishes a tower foot corrosion degree evaluation index according to the corrosion characteristics of the transmission tower foot, comprehensively evaluates the corrosion condition of the transmission tower foot according to the multiple first-level and second-level indexes contained in the tower foot corrosion degree evaluation index, and is more accurate in evaluation. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a method flowchart of the embodiment of the present application. DETAILED DESCRIPTION

[0034] The specific embodiments of the present application are described below to facilitate understanding of the present application by those skilled in the art, but it should be clear that the present application is not limited to the scope of the specific embodiments.

[0035] The present application provides the following technical solutions: a transmission tower foot corrosion evaluation method.

[0036] Embodiment 1

[0037] The present embodiment provides a transmission tower foot corrosion evaluation method, and the specific steps include:

[0038] S1: establishing a tower foot corrosion degree evaluation index according to the corrosion characteristics of the tower foot of the power transmission tower, wherein the tower foot corrosion degree evaluation index comprises three first-level indexes, specifically an appearance quality evaluation index, a corrosion risk evaluation index and a corrosion state evaluation index; wherein the appearance quality evaluation index comprises three second-level indexes, specifically rust at the junction of the tower foot and the protective cap, rust expansion cracks of the protective cap and concrete weathering conditions; the corrosion risk evaluation index comprises five second-level indexes, specifically concrete strength degradation intensity, concrete sound velocity, concrete resistivity, corrosion potential and current density; and the corrosion state evaluation index is the corrosion condition of the tower foot steel, comprising two second-level indexes, specifically corrosion area and corrosion depth;

[0039] S2: obtaining the appearance quality evaluation index of the tower foot of the power transmission tower to be evaluated by macroscopic detection method, and determining whether to perform corrosion risk evaluation and corrosion state evaluation according to the appearance quality evaluation index of the tower foot of the power transmission tower to be evaluated; if the corrosion risk evaluation is performed, S3 is performed, and if the corrosion state evaluation is performed, S4 is performed;

[0040] S21: obtaining the quantitative detection results of the three second-level indexes included in the appearance quality evaluation index of the tower foot of the power transmission tower to be evaluated by macroscopic detection method, calculating the appearance quality evaluation index value according to the quantitative detection results of the second-level indexes and the corresponding weights, presetting the appearance evaluation index value corresponding grade, and determining whether to perform corrosion risk evaluation and corrosion state evaluation according to the appearance quality evaluation index value corresponding grade, as shown in Table 1, the quantitative detection result is specifically 1 if there is a defect corresponding to the second-level index name, otherwise 0; and the appearance quality evaluation index is expressed by the formula as follows:

[0041]

[0042] In the formula, A is the appearance quality evaluation index, A i is the second-level index of the i th appearance quality evaluation index;

[0043] Table 1 appearance quality evaluation index table

[0044]

[0045] S22: as shown in Table 2, the appearance quality evaluation index value corresponding grade includes appearance good, appearance with rust risk and appearance already rusted, if the corresponding grade is the appearance good state, no treatment is needed; if the corresponding grade is the appearance with rust risk state, corrosion risk evaluation is performed; and if the corresponding grade is the appearance already rusted, corrosion state evaluation is performed;

[0046] Table 2 appearance quality evaluation index value corresponding grade

[0047] Appearance quality evaluation index value Appearance quality Corresponding maintenance operation 0 Good No treatment needed 1～2 Rust risk Corrosion risk assessment ≥3 Rust Corrosion state assessment

[0048] S3: performing corrosion risk assessment to obtain a tower foot corrosion risk evaluation index of the to-be-evaluated power transmission tower, and performing corresponding maintenance operation according to the tower foot corrosion risk evaluation index of the to-be-evaluated power transmission tower;

[0049] Preferably, the performing corrosion risk assessment to obtain a tower foot corrosion risk evaluation index of the to-be-evaluated power transmission tower specifically comprises:

[0050] The concrete strength degradation degree and the sound velocity are obtained by ultrasonic-rebound method detection; the concrete resistivity is obtained by four-electrode method detection, the corrosion potential is obtained by the steel bar corrosion detector, and the current density is obtained by linear polarization method;

[0051] S31, the concrete strength degradation degree and the sound velocity obtained by ultrasonic-rebound method detection specifically comprise:

[0052] Ultrasonic wave instrument is used to emit ultrasonic wave on the surface of the selected measurement area of the standard power transmission tower foot structure concrete, and the standard sound time value is recorded; the rebound value is obtained by using the rebound instrument to measure the same measurement area, and the relationship curve between the standard sound time value and the rebound value is established by recording the standard sound time value and the rebound value in pairs, which is used as a standard sample; the ultrasonic wave instrument is used to emit ultrasonic wave on the selected measurement area of the to-be-evaluated power transmission tower foot structure concrete to obtain the sound time value and the sound velocity of the to-be-evaluated power transmission tower foot, and the concrete strength degradation degree is obtained by comparing the sound time value of the to-be-evaluated power transmission tower foot with the sound time value in the standard sample;

[0053] Preferably, in the embodiment, the measurement area division should meet the following requirements: (1) the size of the measurement area is 200*200mm, and the distance between the measurement area boundary and the component boundary should not be less than 50mm; (2) the measurement area should avoid the tower foot steel inside the concrete protective cap;

[0054] S32, the concrete resistivity obtained by four-electrode method detection specifically comprises:

[0055] Four electrodes are prepared, which are divided into two pairs of electrodes, two electrodes are used as current leads, and the other two electrodes are used as voltage leads. Ensure that the electrode surface is clean and in good contact with the concrete surface. It is also necessary to ensure that the distance between the electrodes is appropriate, generally between several centimeters and several tens of centimeters;

[0056] Four electrodes are prepared, which are divided into two pairs of electrodes, two electrodes are used as current leads, and the other two electrodes are used as voltage leads. Ensure that the electrode surface is clean and in good contact with the concrete surface. It is also necessary to ensure that the distance between the electrodes is appropriate, generally between several centimeters and several tens of centimeters;

[0057] The current leads are connected to a direct current source, and the appropriate current size is set, generally between several tens of milliamperes and several amperes. The two current leads are connected to two electrodes to apply a certain intensity of current;

[0058] Connect the voltage leads to a voltage measuring instrument that can measure the voltage difference between the two voltage leads. Connect the other two voltage leads to the other two electrodes corresponding to the current leads to measure the voltage under the action of current;

[0059] According to the measured voltage and current values, calculate the resistivity of the concrete, expressed in formula as:

[0060] Resistivity = Voltage difference / Current intensity;

[0061] Where, in order to improve the measurement accuracy, multiple measurements can be taken and the average value or comprehensive analysis can be taken. Multiple measurements can be taken at different positions, depths or time points to obtain more comprehensive resistivity data;

[0062] S33, obtain the current density by linear polarization method, specifically:

[0063] Prepare an electrode, make sure the electrode surface is clean and in good contact with the concrete surface, stainless steel electrode or other suitable materials can be used;

[0064] Immerse the electrode in the concrete and make sure the electrode is tightly attached to the concrete, the soaking time can be determined according to the needs, the common time range is several minutes to several hours;

[0065] Connect the electrode to a potentiostat to adjust the electrode potential to a stable value, which is usually called working potential, to make the electrode reach a stable polarization state;

[0066] Connect a galvanometer or current measuring device to the electrode to measure the current value through the electrode under the stable potential, which is the current density;

[0067] In this embodiment, linear polarization method is used to obtain current density for quick acquisition of current density, but inevitably, linear polarization method as an approximate method, if more accurate measurement results are needed, current density can be obtained by polarization curve method or alternating current impedance method;

[0068] S34, as shown in Table 3, preset the threshold range of five secondary indexes, the threshold range has corresponding quantitative values, divide the detection values of the five secondary indexes into the corresponding threshold range to obtain the corresponding quantitative values, calculate the corrosion risk evaluation index according to the corresponding quantitative values and the corresponding weight of the secondary index, and the corrosion risk evaluation index is calculated according to the corresponding quantitative values and the corresponding weight of the secondary index, expressed in formula as:

[0069]

[0070] In the formula, B is a corrosion risk evaluation index, B i ω is a weight corresponding to the secondary index of the i-th corrosion risk evaluation index. i ω is a weight corresponding to the secondary index of the i-th corrosion risk evaluation index.

[0071] Table 3: Corrosion risk evaluation index

[0072]

[0073] As shown in Table 4, there are preset corrosion risk evaluation levels, and the corresponding evaluation levels are divided according to the corrosion risk evaluation index values, the evaluation levels include a low corrosion risk level, a medium corrosion risk level and a high corrosion risk level, if the evaluation level is the low corrosion risk level, the transmission tower foot does not need to be processed; if the evaluation level is the medium corrosion risk level, the area is strengthened to be patrolled; if the evaluation level is the high corrosion risk level, corrosion state evaluation is performed;

[0074] Table 4: Corrosion risk evaluation results

[0075] Appearance quality evaluation index Corrosion risk Corresponding maintenance operation 0 Low No treatment needed 1 Medium Increased inspection ≥2 High Corrosion state detection

[0076] S4: corrosion state evaluation is performed to obtain a corrosion state evaluation index of a transmission tower foot to be evaluated, and corresponding maintenance operations are performed according to the corrosion state evaluation index of the transmission tower foot to be evaluated, specifically:

[0077] If the corrosion area is surface without rust products, the corrosion depth does not need to be detected and the transmission tower foot does not need to be processed;

[0078] If the corrosion area is surface with rust products, the corrosion depth is detected;

[0079] If the corrosion depth is 0% to less than 5%, the corrosion state is evaluated as slight, the tower foot is subjected to corrosion prevention operation and the protection cap is reconstructed;

[0080] If the corrosion depth is 5% to less than 20%, the corrosion state is evaluated as medium, the tower foot is subjected to reinforcement operation and the protection cap is reconstructed;

[0081] If the corrosion depth is 20% or more, the corrosion state is evaluated as serious, the tower foot is replaced and the protection cap is reconstructed.

[0082] The above is only an embodiment of the present application, and does not limit the patent range of the present application, and any equivalent structure or equivalent flow transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection range of the present application.

Claims

1. A method for assessing corrosion at the base of power transmission towers, characterized in that, The method includes: Step 1: Establish a corrosion degree evaluation index for the tower feet based on the corrosion characteristics of the tower feet. This index includes three primary indicators: appearance quality evaluation index, corrosion risk evaluation index, and corrosion status evaluation index. The appearance quality evaluation index includes three secondary indicators: rust at the junction of the tower foot and the protective cap, rust-induced cracks in the protective cap, and concrete weathering. The corrosion risk evaluation index includes five secondary indicators: concrete strength degradation intensity, concrete sound velocity, concrete resistivity, corrosion potential, and current density. The corrosion status evaluation index assesses the corrosion of the tower foot steel and includes two secondary indicators: corrosion area and corrosion depth. Step 2: Obtain the appearance quality evaluation indicators of the tower feet to be evaluated using macroscopic inspection methods. Based on these indicators, determine whether a corrosion risk assessment and corrosion status assessment are necessary. Specifically: The quantitative detection results of three secondary indicators, including those for the appearance quality evaluation index of the tower feet of the transmission tower to be evaluated, are obtained through macroscopic detection. The appearance quality evaluation index values ​​are calculated based on the quantitative detection results and corresponding weights of the secondary indicators. Preset levels corresponding to the appearance evaluation index values ​​are used to determine whether a corrosion risk assessment and corrosion status assessment should be conducted. Specifically, the quantitative detection result is set to 1 if a defect corresponding to the secondary indicator name exists, and 0 otherwise. The appearance quality evaluation index is expressed by the following formula: ； In the formula, As an indicator for evaluating appearance quality, For the first Secondary indicators of appearance quality evaluation indicators; If a corrosion risk assessment is performed, proceed to step 3; if a corrosion status assessment is performed, proceed to step 4. Step 3: Conduct a corrosion risk assessment to obtain the corrosion risk assessment index of the tower feet of the transmission tower to be assessed, and carry out corresponding maintenance operations based on the corrosion risk assessment index of the tower feet of the transmission tower to be assessed. Step 4: Conduct a corrosion status assessment to obtain the corrosion status evaluation index for the tower feet of the transmission tower to be assessed. Based on the quantitative detection results of the secondary indicators of the corrosion status evaluation index for the tower feet of the transmission tower to be assessed, conduct a status assessment and perform corresponding maintenance operations, specifically as follows: If the corrosion area is free of surface rust products, then there is no need to test the corrosion depth and there is no need to treat the tower feet of the power transmission tower. If the corrosion area is the surface where rust products are present, then the corrosion depth should be tested. If 0% ≤ corrosion depth < 5%, the corrosion status is assessed as slight, and anti-corrosion operations are performed on the tower feet and the protective cap is rebuilt. If 5% ≤ corrosion depth < 20%, the corrosion status is assessed as moderate, and the tower should be reinforced and the protective cap rebuilt. If the corrosion depth is 20% or less, the corrosion condition is assessed as severe, and the tower feet should be replaced and the protective caps rebuilt.

2. The method for assessing corrosion of transmission tower feet according to claim 1, characterized in that, The appearance quality evaluation index values ​​correspond to the following levels: good appearance, appearance at risk of corrosion, and appearance already corroded. If the corresponding level is good appearance, no treatment is required; if the corresponding level is appearance at risk of corrosion, a corrosion risk assessment is required; if the corresponding level is appearance already corroded, a corrosion status assessment is required.

3. The method for assessing corrosion of transmission tower feet according to claim 1, characterized in that, The specific methods for obtaining corrosion risk assessment indicators for the base corrosion of the transmission tower to be assessed are as follows: The degree of concrete strength degradation and sound velocity were obtained by ultrasonic-rebound method; the concrete resistivity was obtained by four-electrode method; the corrosion potential was obtained by steel corrosion detector; and the current density was obtained by linear polarization method. Five secondary indicators are preset with threshold ranges, and each threshold range has a corresponding quantitative value. The detection values ​​of the five secondary indicators are divided into the corresponding threshold ranges to obtain the corresponding quantitative values. Corrosion risk assessment indicators are calculated based on the corresponding quantitative values ​​and the corresponding weights of the secondary indicators.

4. The method for assessing corrosion of transmission tower feet according to claim 3, characterized in that, The degree of concrete strength degradation and sound velocity were obtained through ultrasonic-rebound testing. Ultrasonic waves are emitted onto the surface of a selected test area of ​​the concrete base structure of a standard transmission tower using an ultrasonic instrument, and the standard acoustic time value is recorded. The rebound value is obtained by measuring the same test area using a rebound hammer. By recording the standard acoustic time value and the rebound value in pairs, a relationship curve between the standard acoustic time value and the rebound value is established. The relationship curve serves as a standard sample. Ultrasonic waves are emitted onto the selected test area of ​​the concrete base structure of the transmission tower to be evaluated using an ultrasonic instrument to obtain the acoustic time value and sound velocity at the base of the transmission tower to be evaluated. The acoustic time value at the base of the transmission tower to be evaluated is compared with the acoustic time value in the standard sample to obtain the degree of concrete strength degradation.

5. The method for assessing corrosion of transmission tower feet according to claim 4, characterized in that, The corrosion risk assessment index, calculated based on the corresponding quantitative values ​​and the weights of the secondary indicators, is expressed by the following formula: ； In the formula, As a corrosion risk assessment indicator, Let be the quantitative value corresponding to the secondary index of the i-th corrosion risk assessment index. The weight is the secondary indicator corresponding to the i-th corrosion risk assessment indicator.

6. The method for assessing corrosion of transmission tower feet according to claim 5, characterized in that, The specific steps for conducting risk assessments and corresponding maintenance operations based on corrosion risk assessment indicators are as follows: There are preset corrosion risk assessment levels. The corresponding assessment levels are divided according to the corrosion risk assessment index values. The assessment levels include low corrosion risk, medium corrosion risk and high corrosion risk. If the assessment level is low corrosion risk, no treatment is required on the tower feet of the transmission tower. If the assessment level is medium corrosion risk, the inspection of the area is strengthened. If the assessment level is high corrosion risk, a corrosion status assessment is carried out.

Images