A method and device for determining the degree of compaction of the ground in which a telegraph pole is embedded

Abstract

The application provides a kind of electric pole burying land hard degree determination method and detection device, it is related to electric power facility safety evaluation technical field.The method obtains electric pole double channel signal by impact elastic wave detection equipment, and the superposition state waveform signal is analyzed, the amplitude of the first pole bottom reflected wave, the first pole top reflected wave and the second pole top reflected wave is extracted, the amplitude ratio R 1 and R 2 are calculated respectively R 1、 R 2 is combined with the exposed length of electric pole H And equivalent signal receiving point H 0, the equivalent attenuation coefficient of buried section η g Is calculated;Finally, the electric pole burying soil quality condition is determined based on η g The application can quantify the surrounding soil body's wrapping and constraint ability to electric pole without excavating pole base, effectively avoids the interference of additional loss caused by external hanging or connecting structure on determination result, improves the efficiency and implementability of in-service electric pole burying state detection, and provides a new evaluation dimension for health assessment of in-service electric pole.

Description

Technical Field

[0001] This invention relates to the field of power facility safety evaluation technology, specifically to a method and testing device for determining the soil hardness of buried power poles. It is applicable to the determination and testing of soil conditions for buried power poles in service, and can provide an evaluation basis for the health assessment of in-service power poles by combining data such as the burial depth and pole body deterioration. Background Technology

[0002] my country has hundreds of millions of utility poles in service, which are widely distributed across mountainous, hilly, plain, and urban areas. Due to different geological conditions, the construction standards and health assessment standards for these utility poles vary.

[0003] Currently, the main evaluation indicators for the construction quality and health of utility poles include burial depth, pole tilt and deterioration, and apparent cracks, but no separate evaluation indicators have been proposed for the soil conditions in which they are buried.

[0004] Therefore, there is an urgent need in this field for a method and testing device for determining the soil hardness of buried utility poles, to increase the dimensions of health assessment indicators for in-service utility poles, and to ensure the safe operation of in-service utility poles and power transmission networks.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method and testing device for determining the soil hardness of buried utility poles, thereby increasing the dimensions of health assessment indicators for in-service utility poles and ensuring the safe operation of in-service utility poles and power transmission networks.

[0007] To achieve the above objectives, the present invention provides the following solution: A method for determining the soil hardness of a utility pole's burial site includes the following steps: S1: Obtain dual-channel signals from the utility pole using an impact elastic wave detection device. The specific steps are as follows: S11: Fix the dual-channel sensor bracket to the utility pole, and continuously apply elastic wave excitation hammer to the same utility pole. m The second impact was recorded using a dual-channel sensor to receive the elastic wave signal. m The elastic wave signal of the secondary impact: , The dual-channel sensor is an accelerometer, with channel 0 located near the top of the utility pole and channel 1 located near the buried side of the utility pole. S12: Perform zero-point correction and frequency band filtering on each channel signal. The specific steps are as follows: S121: Calculate the mean value of the preamplifier noise segment for each channel:

[0008] In the formula, i This refers to the sensor channel number; N 0 represents the number of sampling points included in the front noise segment; n The discrete sampling point number; S122: Correct the original signal using the noise mean:

[0009] In the formula, k i For the first i The sensitivity coefficient of each accelerometer; S123: Calculate the signal spectrum after excitation and the pre-excitation noise spectrum respectively, and determine the effective frequency band as the continuous frequency range where the ratio of signal spectrum power to noise spectrum power is not less than 3. The same frequency band filtering is used for the dual-channel signals to avoid different phase changes in the two channels.

[0010] S13: The elastic wave signals from the two channels are superimposed to obtain the final elastic wave analysis signal. The specific steps are as follows: S131: Based on sensor spacing Initial P-wave velocity and sampling frequency Calculate the initial sampling point delay In the Calculate the normalized cross-correlation coefficient of the dual-channel signal within the integer sampling point range centered on the center, and obtain the optimal sampling point delay. and according to Calculate the actual time delay and P-wave velocity, specifically: S1311: Calculate the initial sampling point delay ; S1312: In Calculate the normalized cross-correlation coefficient of the two channel signals:

[0011] In the formula, For the first m The second impact has a time delay at the sampling point. The normalized cross-correlation coefficient of the two channels; To ensure and The set of sampling points, all within the effective signal range. The time delay corresponding to the maximum cross-correlation value is taken according to equation (3): And convert it into time. Corrected P-wave velocity: The final P-wave velocity is taken as the median of the effective impact results. .

[0012] S132: Perform noise-weighted superposition processing on the two channel signals, specifically: S1321: Determine the weights based on the noise variance of the two channels: In the formula The standard deviation of the front noise. , It is a tiny positive number, taken as 0.0001, and is dimensionless.

[0013] S1322: Based on the superposition of dual-channel signals, the superimposed signal of a single impact is obtained:

[0014] In the formula, For the first arriving channel signal, This is the signal for the later-arriving channel.

[0015] S133: Integrates multiple impact signals, specifically: S1331: Extract the initial arrival amplitude value for each impact. Perform overall normalization on a single signal:

[0016] S1332: Extract the pointwise median of each normalized signal to form a superposition waveform signal.

[0017] S2: Analyze the superposition waveform signal to find the two elastic wave reflection peak signals at the bottom and top of the first pole. amplitude Calculate the amplitude ratio The specific steps are as follows: S21: Analyze the superposition state waveform signal and calculate the total length of the utility pole. L burial depth D、 Exposed length H and P wave speed ; S22: Confirm the first elastic wave bar bottom signal travel (excitation point ~ bar bottom ~ bar top ~ reference point):

[0018] S23: Determine the first travel distance of the elastic wave signal at the top of the utility pole (excitation point ~ pole top ~ reference point):

[0019] S24: Calculate the echo window based on travel distance and wave velocity, specifically: S241: Calculate echo travel time: In the formula For the first x The propagation path of the first echo.

[0020] S242: Set the window half-width to: In the formula This is the minimum time interval between this echo and its adjacent echo.

[0021] S243: Final adaptive echo selection window .

[0022] S25: Based on the superposition state waveform signal and echo window, determine the peak amplitude values ​​of the first signal waveforms at the bottom and top of the utility pole. , specifically: S251: Constructing an analytical envelope for a superposition-state signal: In the formula This represents the orthogonal transformation component.

[0023] S252: After the excitation initiation point, the local maxima satisfying the following equation will be used as candidate echo peaks: .

[0024] S253: Within the corresponding echo window, the echo amplitude is defined by the envelope peak value. ; S254: Calculate according to step S253 .

[0025] S26: Calculate the amplitude ratio of the first elastic wave velocity after reflection from the bottom and top of the rod: .

[0026] S3: Analyze the superimposed waveform signal to find the peak signal of the elastic wave reflection in the direction of the second pole top. amplitude and the amplitude of the first reciprocating motion at the top of the rod. Calculate the amplitude ratio The specific steps are as follows: S31: Determine the travel distance of the elastic wave signal at the top of the second utility pole (excitation point ~ pole top ~ reference point ~ pole bottom ~ pole top ~ reference point):

[0027] S32: Based on the travel distance and echo window, select the second pole top echo, specifically: S321: Based on the two identified echoes, predict the travel time of the second pole-top echo. ; S322: In Search for envelope peaks within the echo window and select the peaks that match the echo. The peak with the smallest time distance and the largest signal-to-noise ratio within the allowable time deviation range is taken as the second pole top echo.

[0028] S33: Same as step S25, determine the peak amplitude value of the signal waveform at the top of the utility pole for the second time. .

[0029] S34: Calculate the amplitude ratio of the first elastic wave velocity after reflection from the bottom and top of the rod: .

[0030] S4: Joint , Compared with the known exposed length of utility poles and equivalent signal receiving point Calculate the equivalent attenuation coefficient of the buried section of the utility pole. The specific steps are as follows: S41: Amplitude of the first elastic wave signal at the base of the utility pole The main steps in expression evaluation include: S411: Determine the amplitude of the elastic wave signal after the elastic wave has traveled the first pole bottom signal distance, as shown in the following formula:

[0031] In the formula, The initial amplitude of the elastic wave reference point. The elastic wave distance attenuation coefficient (in exposed air is ). In the buried area ), This refers to the travel distance of an elastic wave.

[0032] S412: Substituting equation (7) into equation (10) yields:

[0033] S42: Calculate the amplitude of the first elastic wave signal at the top of the utility pole in the same manner as step S41. :

[0034] S43: Calculate the amplitude of the second elastic wave signal at the top of the utility pole in the same manner as step S41. :

[0035] S44: Calculate the equivalent attenuation coefficient of the buried section based on the formulas in steps S41-S43. , specifically: S441: Amplitude ratio based on steps 2 and 3 , Substituting equations (11), (12), and (13) into the equations, we get:

[0036]

[0037] S442: Taking the natural logarithm of both sides of equations (14) and (15), we get:

[0038]

[0039] S443: Solve the simultaneous equations (16) and (17). :

[0040]

[0041] S5: Based on the equivalent attenuation coefficient of the buried section When determining the soil conditions for the buried utility pole, the equivalent attenuation coefficient of the buried section is not the propagation attenuation coefficient of the soil material itself, but rather a pole-soil coupling equivalent attenuation index that comprehensively includes propagation loss within the pole, coupling loss at the pole-soil interface, and fixed reflection loss. Specifically: S511: Definition , Equations (18) and (19) can be rewritten as follows:

[0042]

[0043] S512: Defines the additional elastic wave attenuation at exposed utility pole locations. The cumulative additional attenuation caused by the external hanging, clamping, flange, and splicing parts on the upper part of the pole is used to characterize the equation (21) as follows:

[0044] Note: This formula is valid only if there are no special structures such as external hanging or splicing on the pole body from the equivalent excitation point and signal receiving point to the ground.

[0045] S513: Introduction Then, the formula for calculating the elastic wave attenuation coefficient is:

[0046]

[0047] S514: According to equations (23), (24) and ,calculate Range of values

[0048]

[0049] S515: According to By substituting the range of values ​​into equation (24), the equivalent attenuation coefficient of the buried section is obtained. Range:

[0050]

[0051] In the formula, It is a conservative lower bound obtained assuming no external losses; It interprets all the differences in the second path as the upper limit when there is external loss; the more externally attached utility poles there are, the wider the range becomes.

[0052] S516: Equivalent attenuation coefficient for buried sections The range is: ; S52: Calculate the center estimate of the buried additional attenuation coefficient And determine the geological conditions of the burial area, specifically: S521: Calculate the additional attenuation coefficient for buried surfaces:

[0053] S522: Calculate the uncertainty introduced by the range of the interval: ; S523: Calculate the concentration of intervals : In the formula It is a positive constant, taken as 0.0001, and is dimensionless.

[0054] S524: Obtain the final equivalent attenuation coefficient of the buried section. ; S53: Determine the geological conditions of the area where the utility pole is buried, specifically: S531: According to The reliability of the interval is used to determine whether the data can be used to assess the geological conditions of areas where utility poles are buried. The judgment criteria are as follows:

[0055] S532: Define reference values ​​for soft geological conditions during installation Compared with hard reference value This set of parameters needs to be set according to the pole type, geometric dimensions, burial depth range, splicing status, external hanging status, and sensor installation location. For the same structural configuration category, the same hard and soft reference attenuation values ​​are used during the testing process.

[0056] S533: Definition of Burial Condition Index BCI , specifically:

[0057] S534: Determine the burial conditions based on the burial condition index, specifically (the listed data is obtained through...). , calculate).

[0058] Table 1. Burial Condition Judgment Table

[0059] A device for detecting the soil hardness of buried utility poles includes an elastic wave excitation assembly, a dual-channel accelerometer sensor assembly, a sensor mounting bracket, a data acquisition module, a parameter input module, a signal processing module, an attenuation interval calculation module, and a grade output module. The dual-channel accelerometer sensor assembly is used to acquire the dual-channel elastic wave response signal of the utility pole under multiple impacts, and the parameter input module is used to obtain the exposed axial length of the utility pole. H burial depth D , reference point location Sensor spacing Sampling frequency The signal processing module is used to perform dual-channel time delay correction, noise weighted fusion, echo window determination, extraction of three echo amplitudes, and calculation of two elastic wave attenuation parameters. The attenuation interval calculation module is used to calculate the equivalent attenuation coefficient interval and interval convergence of the buried pole-soil coupling based on the non-negative constraint of the additional attenuation amount. The grade output module is used to output the soil hardness grade corresponding to the tested utility pole based on the equivalent attenuation coefficient interval and the buried condition index. The detection device is configured to perform the above methods.

[0060] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention eliminates the need for excavating pole foundations and for comparative testing of the same utility pole with and without external supports. It quantifies the surrounding soil's ability to enclose and constrain the utility pole, improving the efficiency and feasibility of detecting the installation status of in-service utility poles.

[0061] 2. This invention addresses the issue of unknown additional attenuation caused by external structures, clamps, flanges, or splices on the upper part of in-service utility poles. Under the condition that there are no special additional loss structures along the common propagation path, it introduces the additional attenuation of the differential propagation path. Based on the physical constraint that the attenuation coefficient of the exposed pole, the equivalent attenuation coefficient of the pole-soil coupling in the buried section, and the additional attenuation are all non-negative, a feasible range for the equivalent attenuation coefficient of the pole-soil coupling in the buried section is calculated. This effectively avoids misjudging the additional loss caused by external structures or splices as the degree of soil hardness, and also avoids the abnormal amplification of results caused by simply subtracting the two attenuation coefficients. The detection results can be output in the form of "range, convergence, and grade," improving the robustness, conservatism, and engineering reliability of the determination of buried conditions under complex in-service conditions. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0063] Figure 1 A schematic diagram of the method for determining the soil hardness when burying utility poles, provided in an embodiment of the present invention.

[0064] Figure 2 This is a schematic diagram illustrating the calculation of the travel distance of elastic wave signals at the bottom and top of the pole, provided in an embodiment of the present invention.

[0065] Figure 3 This is a schematic diagram illustrating the determination of the travel distance of the elastic wave signal at the top of the utility pole in the second embodiment of the present invention. Detailed Implementation

[0066] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0067] The purpose of this invention is to provide a method and testing device for determining the soil hardness of buried utility poles, thereby increasing the dimensions of health assessment indicators for in-service utility poles and ensuring the safe operation of in-service utility poles and power transmission networks.

[0068] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the following description is provided in conjunction with the accompanying drawings. Figure 1-3 The present invention will be further described in detail below with reference to specific embodiments.

[0069] Example 1: This embodiment provides a method for determining the soil hardness when a utility pole is buried, as shown in the flowchart below. Figure 1 As shown, it includes the following steps: S1: Use shock elastic wave detection equipment to obtain dual-channel signals from utility poles; like Figure 2-3 As shown, Figure 2 CH0 represents the sensor channel near the top of the pole, and CH1 represents the sensor channel near the buried side. The distance between them is △ L .

[0070] S2: Analyze the superposition waveform signal to find the two elastic wave reflection peak signals at the bottom and top of the first pole. amplitude Calculate the amplitude ratio ; S3: Analyze the superimposed waveform signal to find the peak signal of the elastic wave reflection in the direction of the second pole top. amplitude and the amplitude of the first reciprocating motion at the top of the rod. Calculate the amplitude ratio ; S4: Joint , Compared with the known exposed length of utility poles and equivalent signal receiving point Calculate the equivalent attenuation coefficient of the buried section of the utility pole. ; S5: Based on the equivalent attenuation coefficient of the buried section Determine the soil conditions for burying utility poles.

[0071] Example 1: The utility poles were inspected under three different burial conditions: urban areas (concrete-buried areas, with concrete on the surface and soil underneath), flower beds, and ordinary soil. The algorithm of this invention was used for analysis, and the data obtained are shown in the statistical table below.

[0072] Table 1. Statistical Table of Buried Conditions

[0073] As shown in the table above, based on the data obtained from the analysis of the three burial conditions, the BCI indices obtained by this algorithm are 100, 60.52, and 32.99, respectively. According to the judgment rules of this algorithm, the soil hardness of the burial area under the three burial conditions is Level I, hard; Level II, relatively hard; and Level III, relatively soft.

[0074] Example 2: Confirmation using mathematical statistics .

[0075] Method 1: Data from over 40 utility poles were collected and grouped according to their burial conditions (cement, level ground, gravel, clay, etc.) from hardest to softest. Hardest and softest reference groups were established for analysis and statistical purposes to determine... , ( i (as group number), and for Sort the data in ascending order, find the median of the hard and soft groups respectively, and determine the median. The indicators are as follows:

[0076]

[0077] Method 2: Analysis of the inspection data from more than 30 utility poles yielded the following results: After that, directly to Sort the data in ascending order, and take the 20th and 80th percentiles as... The metrics yielded the following final data:

[0078]

[0079] The resulting judgment data is as follows: Table 2 Judgment Data Table

[0080] Using the judgment criteria obtained from Method 2, the 15 sets of utility pole test data were judged, and the results are shown in the table below.

[0081] Table 3 Detection Data Judgment Results Table

[0082] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0083] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for determining the soil hardness for which a utility pole is buried, characterized in that, include: Obtain the exposed axial length of the utility pole to be tested H burial depth D and the axial distance from the equivalent excitation or signal receiving reference point to the ground. At least three elastic wave impacts were applied to the pole under test, and dual-channel elastic wave response signals were collected. The first echo reflected from the pole base, the first echo reflected from the pole top, and the second echo reflected from the pole top were determined from the elastic wave response signals, and the corresponding echo amplitudes were obtained respectively. , and ; The first amplitude ratio is calculated based on the echo amplitude. Second amplitude ratio The equivalent attenuation coefficient of the buried section pole-soil coupling is calculated based on the first amplitude ratio, the second amplitude ratio, the exposed axial length, the burial depth, and the location of the reference point. The surrounding soil's ability to wrap and constrain the utility pole is determined based on the equivalent attenuation coefficient of the buried section pole-soil coupling, and the corresponding soil hardness level is output.

2. The method for determining the soil hardness for burying utility poles according to claim 1, characterized in that, The dual-channel elastic wave response signal is acquired by a first accelerometer and a second accelerometer spaced apart along the axial direction of the utility pole; based on the axial distance between the two accelerometers... Sampling frequency and initial P-wave velocity Determine the initial sampling point delay The optimal sampling point delay is calculated by normalized cross-correlation. ,according to The propagation delay and P-wave velocity are calculated, and the dual-channel signals are time-delay corrected according to the arrival order of the first and last channels. The fusion weights are determined based on the pre-noise variance of the two channels. The time-delay corrected dual-channel signals are weighted and fused and single-impact normalized. The normalized signals of multiple impacts are fused point-by-point median to obtain the superimposed waveform used to determine the echo position.

3. The method for determining the soil hardness for burying utility poles according to claim 2, characterized in that, Based on the echo travel after the first reflection from the bottom of the pole First pole top echo travel And the second club top echo travel The echo windows after the first pole bottom reflection, the first pole top echo window, and the second pole top echo window are determined based on the P-wave velocity. The positions of each echo window are determined using the superimposed waveform, and the envelope peak value is extracted within the same echo window of the time delay correction signal corresponding to the impact to obtain the corresponding echo amplitude. , and Then calculate the first amplitude ratio Second amplitude ratio .

4. The method for determining the soil hardness for burying utility poles according to claim 3, characterized in that, When there are no external attachments, clamps, flanges, connectors, or other additional loss structures on the common propagation path from the ground to the equivalent excitation or signal receiving reference point, and the additional loss structures are located on the differential propagation path from the reference point to the top of the pole, an establishment is made. and The attenuation relationship, where, The equivalent attenuation coefficient for the exposed rod section. The equivalent attenuation coefficient for the buried section pole-soil coupling is given. The dimensionless logarithmic attenuation is added to the differential propagation path, with a lower limit for the added attenuation. The upper limit of additional attenuation is .

5. The method for determining the soil hardness for burying utility poles according to claim 4, characterized in that, Calculate the midpoint of the interval based on the equivalent attenuation coefficient interval of the buried section pole-soil coupling. and interval convergence In the formula ;when When the value is greater than 0.75, the midpoint of the interval is... As an evaluation factor for attenuation coefficient, when When, the lower limit of the interval is... As an evaluation factor for attenuation coefficient, when Output buried conditions pending verification; for test results that can be used for grade evaluation, according to... Calculate the buried condition index, where, As a soft reference attenuation coefficient, For hard reference attenuation coefficient and Based on the burial condition index, the soil hardness of the buried section is divided into four levels: soft, relatively soft, relatively hard, and hard.

6. A device for detecting the soil hardness of buried utility poles, characterized in that, The system includes an elastic wave excitation assembly, a dual-channel accelerometer sensor assembly, a sensor mounting bracket, a data acquisition module, a parameter input module, a signal processing module, an attenuation range calculation module, and a grade output module. The dual-channel accelerometer sensor assembly is used to acquire the dual-channel elastic wave response signal of the utility pole under multiple impacts, and the parameter input module is used to obtain the exposed axial length of the utility pole. H burial depth D , reference point location Sensor spacing Sampling frequency The signal processing module is used to perform dual-channel time delay correction, noise weighted fusion, echo window determination, three echo amplitude extraction and two elastic wave attenuation parameter calculations. The attenuation interval calculation module is used to calculate the equivalent attenuation coefficient interval and interval convergence of the buried pole-soil coupling according to the non-negative constraint of the additional attenuation amount. The grade output module is used to output the soil hardness grade corresponding to the tested utility pole according to the equivalent attenuation coefficient interval and the buried condition index. The detection device is configured to perform the method for determining the soil hardness of the buried utility pole as described in any one of claims 1 to 5.

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