A method and system for detecting compressive strength of concrete used in construction projects

Abstract

The present application relates to the technical field of compressive strength testing, and specifically to a method and system for testing the compressive strength of concrete for construction projects, the method comprising: obtaining ultrasonic sound velocity and rebound representative values ​​at each measurement position of concrete, calculating the acoustic wave interference degree at each measurement position at each acquisition time, and then obtaining the interference difference degree at each measurement position at each acquisition time, clustering the interference difference degree, analyzing the difference between each clustering cluster and other clustering clusters on the mean value of the interference difference degree to obtain the propagation credibility, analyzing the difference in ultrasonic sound velocity and the interference difference degree between each measurement position to be corrected and the reference measurement position, obtaining the sound velocity correction value, calculating the sound velocity representative value of each position to be corrected and the sound velocity representative value of each reference measurement position; obtaining the compressive strength of each measurement position of concrete based on the sound velocity representative value and the rebound representative value of each measurement position. The present application improves the accuracy of concrete compressive strength detection.

Description

Technical Field

[0001] The present application relates to the technical field of compressive strength testing, and in particular to a method and system for testing the compressive strength of concrete used in construction projects. Background Art

[0002] With the development of economic construction, concrete has become one of the important building materials in current construction projects due to its advantages of low price, convenient material acquisition and good performance. At the same time, the quality of concrete is an important factor that directly affects the safety and reliability of construction projects, and the compressive strength of concrete is an important support for determining the stability and safety of concrete structures and construction performance. Therefore, the physical test of the compressive strength of concrete in construction projects is particularly important and has important practical significance.

[0003] The non-destructive testing technology of concrete compressive strength mainly includes the rebound method, ultrasonic method and ultrasonic rebound method. Among them, the ultrasonic rebound comprehensive method is a comprehensive ultrasonic-rebound method. It comprehensively estimates the compressive strength of structural concrete by measuring the ultrasonic sound velocity inside the hardened concrete and the rebound value of the hardness of the hardened concrete surface. This method combines the advantages of ultrasonic and rebound tester non-destructive testing technologies to improve the reliability and accuracy of concrete strength testing. However, when the traditional ultrasonic rebound comprehensive method measures the compressive strength of concrete, the ultrasonic sound velocity is easily affected by the interference of metal substances inside the concrete, making it impossible to accurately calculate the compressive strength of concrete, resulting in inaccurate concrete compressive strength testing. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a method and system for testing the compressive strength of concrete for construction projects. The technical solutions adopted are as follows:

[0005] The present invention provides a method for testing the compressive strength of concrete for construction projects, comprising the following steps:

[0006] Obtaining a rebound representative value at each measuring position of the concrete to be tested and the ultrasonic sound velocity at each acquisition time, wherein the rebound representative value is an average of the rebound values ​​of multiple rebound measuring points at the measuring position;

[0007] Perform modal decomposition on the ultrasonic sound velocity of all local neighboring moments of each measurement position at each acquisition moment, analyze the range and information entropy of each modal component, and obtain the acoustic interference degree of each measurement position at each acquisition moment;

[0008] Obtaining the interference difference of each measurement position at each acquisition moment based on the difference in acoustic wave interference between each measurement position and other measurement positions at each acquisition moment;

[0009] Cluster the interference differences of the measurement positions at all acquisition moments, and obtain the propagation credibility of the ultrasonic wave at each measurement position according to the mean value of the interference differences within each cluster in the clustering result, and the difference between each cluster and other clusters regarding the mean value of the interference differences, so as to divide the measurement positions into reference measurement positions and measurement positions to be corrected;

[0010] By analyzing the numerical difference and directional difference of the ultrasonic sound velocity between each measurement position to be corrected and the reference measurement position, as well as the interference difference of each measurement position to be corrected at each acquisition time, the sound velocity correction value of the ultrasonic wave at each measurement position to be corrected at each acquisition time is obtained;

[0011] The representative sound velocity value of each measurement position to be corrected is obtained by combining the sound velocity correction value of each measurement position to be corrected at all acquisition times. The representative sound velocity value of each reference measurement position is the average ultrasonic sound velocity of the reference measurement position at all acquisition times. The compressive strength of each measurement position of the concrete to be tested is obtained based on the representative sound velocity value and the rebound representative value of each measurement position.

[0012] Preferably, all the local neighboring moments of each collection moment are a plurality of collection moments with the shortest time intervals to each collection moment.

[0013] Preferably, the calculation formula for the acoustic interference degree of each measurement position at each acquisition time is:

[0014] , where is the acoustic interference degree at the sth measurement position at the acquisition time t, is the modal sequence number of the local sound velocity sequence at the acquisition time t at the sth measurement position, is the information entropy of the ath mode sequence of the local sound velocity sequence at the sth measurement position at the acquisition time t, It is the range of the ath modal sequence of the local sound velocity sequence at the acquisition time t at the sth measurement position; wherein the local sound velocity sequence is composed of the ultrasonic sound velocities of all local neighboring moments of the acquisition time t arranged in chronological order, and the local sound velocity sequence is modally decomposed to obtain each modal component, and all elements in each modal component constitute each modal sequence.

[0015] Preferably, the calculation formula for the interference difference of each measurement position at each acquisition time is:

[0016] , where is the interference difference of the sth measurement position at the acquisition time t, is the normalization function, is the number of measurement locations, is the difference between the acoustic interference degree at the acquisition time t of the s-th measurement position and the acoustic interference degree at the acquisition time t of the v-th measurement position, is the judgment function, when When , the judgment function value is 1, when When , the judgment function value is 0.

[0017] Preferably, the corresponding calculation formula for the propagation credibility of the ultrasonic wave at each measurement position is:

[0018] , where is the propagation reliability of the ultrasonic wave at the sth measurement position, is an exponential function with a natural constant as the base, Q is the number of clusters in the clustering result corresponding to the sth measurement position, and are respectively the mean interference differences of the jth and j-1th clusters in the clustering results corresponding to the sth measurement position.

[0019] Preferably, the reference measurement positions and the measurement positions to be corrected are further divided as follows: the measurement position corresponding to the maximum propagation credibility is used as the reference measurement position, and the remaining other measurement positions are the measurement positions to be corrected.

[0020] Preferably, the corresponding calculation formula of the sound velocity correction value of the ultrasonic wave at each acquisition time at each measurement position to be corrected is:

[0021] , where is the corrected value of the ultrasonic sound velocity at the i-th measurement position to be corrected at the acquisition time t, , are the ultrasonic sound velocity and interference difference of the i-th measurement position to be corrected at the acquisition time t, is the ultrasonic sound velocity at the reference measurement position at the acquisition time t.

[0022] Preferably, the representative value of the sound velocity of each position to be corrected is the average value of the sound velocity correction value of the ultrasonic wave at each measurement position to be corrected at all acquisition moments.

[0023] Preferably, the step of obtaining the compressive strength of each measuring position of the concrete to be tested based on the representative value of the speed of sound and the representative value of the rebound at each measuring position comprises:

[0024] Preset each standard measurement position in the preselected concrete, obtain the rebound representative value of each standard measurement position, take the average value of the ultrasonic sound velocity of each standard measurement position at all acquisition moments as the sound velocity representative value of each standard measurement position, and obtain the standard compressive strength of each standard position through compressive strength test;

[0025] The representative rebound values, representative sound velocity values ​​and standard compressive strength of all standard measurement positions are fitted to obtain the compressive strength function, and the compressive strength of each measurement position of the concrete to be tested is calculated.

[0026] An embodiment of the present application also provides a concrete compressive strength detection system for construction projects, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of any one of the above methods when executing the computer program.

[0027] From the above, it can be seen that the concrete compressive strength detection method and system for construction engineering provided by the present application have at least the following beneficial effects:

[0028] The present application takes into account that when the traditional ultrasonic rebound comprehensive method is used to measure the compressive strength of concrete, the ultrasonic sound velocity is easily affected by the interference of metal substances inside the concrete, making it impossible to accurately calculate the compressive strength of concrete, resulting in inaccurate concrete compressive strength detection. Therefore, the present invention performs characteristic analysis on the interference of ultrasonic waves based on the modal component of ultrasonic sound velocity, constructs the sound wave interference degree, reflects the extent of the influence of external interference on the propagation of ultrasonic waves, and is used to improve the subsequent analysis of metal interference characteristics; further, based on the difference between the sound wave interference characteristics between different measurement positions, constructs the interference difference degree, reflects the extent of the interference of ultrasonic sound velocity by metal at each acquisition moment at different measurement positions, so that the error of ultrasonic sound velocity can be accurately corrected based on the extent of the interference of ultrasonic sound velocity by metal; further, based on the cluster analysis of the interference difference degree at different measurement positions, constructs the propagation credibility of ultrasonic waves, and screens out the reference measurement positions with high accuracy of ultrasonic sound velocity, so that the error of ultrasonic sound velocity at the measurement position to be corrected is corrected based on the ultrasonic sound velocity and the interference difference degree at the reference measurement position, and the sound velocity correction value and the sound velocity representative value are obtained, and the detection of concrete compressive strength is realized, so as to solve the problem that the ultrasonic sound velocity is easily affected by the interference of metal substances inside the concrete, making it impossible to accurately calculate the compressive strength of concrete, and improve the accuracy of concrete compressive strength detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 A flowchart of the steps of a method for testing the compressive strength of concrete for construction engineering provided in this application;

[0031] Figure 2 Schematic diagram of rebound value measurement points provided for this application;

[0032] Figure 3 A schematic diagram of the waveform of the modal component 1 after the modal decomposition of the local sound velocity sequence provided in this application;

[0033] Figure 4 A schematic diagram of the waveform of the modal component 2 after the modal decomposition of the local sound velocity sequence provided in this application;

[0034] Figure 5 A waveform diagram of the modal component 3 after modal decomposition of the local sound velocity sequence provided in this application;

[0035] Figure 6 A waveform diagram of the modal component 4 after modal decomposition of the local sound velocity sequence provided in this application;

[0036] Figure 7 A waveform diagram of a modal component 5 after modal decomposition of a local sound velocity sequence provided in this application;

[0037] Figure 8 This is a waveform diagram of the modal component 6 after the modal decomposition of the local sound velocity sequence provided in this application. DETAILED DESCRIPTION

[0038] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of a concrete compressive strength detection method and system for construction engineering proposed in accordance with the present application, its specific implementation method, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0039] Unless otherwise specified and limited, terms such as "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such articles or devices. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the article or device including the element. In addition, the term "and\or" used herein includes any and all combinations of one or more related listed items. All technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application.

[0040] The following is a detailed description of a concrete compressive strength testing method and system for construction projects provided by the present application with reference to the accompanying drawings.

[0041] See also Figure 1 , which shows a flowchart of a method for testing the compressive strength of concrete for construction engineering provided by an embodiment of the present application, comprising the following steps:

[0042] Step 1: Obtain the rebound representative value of each measurement position of the concrete to be tested and the ultrasonic sound velocity at each acquisition time, wherein the rebound representative value is the average value of the rebound values ​​of multiple rebound measurement points in the measurement position.

[0043] The purpose of this embodiment is to analyze the interference characteristics during ultrasonic propagation, and to perform error correction on the ultrasonic sound velocity based on the size of the ultrasonic interference characteristics caused by metal, so as to avoid the problem that the ultrasonic sound velocity is easily affected by the interference of metal substances inside the concrete, resulting in the inability to accurately calculate the compressive strength of the concrete, thereby improving the accuracy of concrete compressive strength detection.

[0044] In this embodiment, steel fiber concrete is cast using a common concrete mix ratio. Nine measurement areas of the same size are selected in the central area of ​​one side of the concrete to be tested. The area of ​​each measurement area is 0.01 square meters. An ultrasonic detector is used to sample the ultrasonic sound velocity at the center of each measurement area at each sampling time to obtain the ultrasonic sound velocity at each measurement position at each sampling time. In this embodiment, the sampling rate of the ultrasonic sound velocity is 50kHz and the sampling time is 1s. The implementer can set it by himself in the actual application scenario.

[0045] At the same time, in this embodiment, in order to avoid noise interference during data collection, 16 points are evenly selected in each measurement area, and the rebound value of each rebound measurement point is measured using a concrete rebound tester. The average rebound value of the 16 rebound measurement points in each measurement area is recorded as the rebound representative value of each measurement area. Specifically, the schematic diagram of the rebound value measurement point is as follows: Figure 2 As shown, Figure 2 There are 9 measurement areas in the system, and 16 rebound value measurement points in each area.

[0046] Step 2: Perform modal decomposition on the ultrasonic sound velocity of all local neighboring moments of each measurement position at each acquisition moment, analyze the range and information entropy of each modal component, and obtain the acoustic interference degree of each measurement position at each acquisition moment.

[0047] Normally, when using an ultrasonic detector to measure the ultrasonic sound velocity inside steel fiber concrete, it is easily affected by the interference of metal substances, humidity and other factors inside the concrete. For example, other metal substances such as steel bars inside the concrete will cause unstable abnormal changes in the ultrasonic sound velocity in the measurement area of ​​the concrete, resulting in poor accuracy in the concrete compressive strength test. Therefore, in order to more accurately test the compressive strength of concrete, it is necessary to analyze the interference characteristics of the ultrasonic sound velocity in each measurement area.

[0048] In order to analyze the interference characteristics of different acquisition moments, the 100 acquisition moments with the closest time interval to each acquisition moment are taken as the local neighboring moments of each acquisition moment;

[0049] Furthermore, for each measurement position, a sequence of ultrasonic sound velocities at all local neighboring moments at each acquisition moment in chronological order is recorded as a local sound velocity sequence at each acquisition moment.

[0050] In order to extract the interference characteristics of ultrasonic sound speed at different acquisition moments, for each measurement position, the local sound speed sequence at each acquisition moment is input into the VMD variational mode decomposition algorithm (Variational Mode Decomposition). In this embodiment, the preset mode number, penalty coefficient and convergence tolerance in the variational mode decomposition algorithm are 6, 1800 and 3e-6 respectively. The VMD variational mode decomposition algorithm outputs the preset mode number of modal components of the local sound speed sequence at each acquisition moment, and all elements in each modal component form each modal sequence, wherein the VMD variational mode decomposition algorithm is a well-known technology, and the specific process will not be repeated. Specifically, in this embodiment, the waveform diagram of modal component 1 after the local sound speed sequence is modally decomposed is as follows: Figure 3 As shown, Figure 3 is the waveform diagram of modal component 1. Similarly, the waveform diagram of modal component 2 is as follows Figure 4 As shown, the waveform diagram of modal component 3 is as follows Figure 5 As shown, the waveform diagram of modal component 4 is as follows Figure 6 As shown, the waveform diagram of modal component 5 is as follows Figure 7 As shown, the waveform diagram of modal component 6 is as follows Figure 8 shown.

[0051] Under normal circumstances, when the propagation of ultrasonic waves in concrete is less disturbed by the outside world, the number of effective modes among all the decomposed modal components is small, and most modal sequences will show stable changes. However, when the propagation of ultrasonic waves in concrete is greatly disturbed by the outside world, the number of effective modes among all the decomposed modal components is large, and due to the influence of external interference components, most modal sequences will show more complex fluctuation characteristics.

[0052] Based on the above analysis, the acoustic interference degree at each measurement position at each acquisition moment is calculated. Preferably, the specific expression in this embodiment is:

[0053] , where is the acoustic interference degree at the sth measurement position at the acquisition time t, is the modal sequence number of the local sound velocity sequence at the acquisition time t at the sth measurement position, is the information entropy of the ath mode sequence of the local sound velocity sequence at the sth measurement position at the acquisition time t, is the range of the ath modal sequence of the local sound velocity sequence at the sth measurement position at the acquisition time t, where the calculation of information entropy and range are both well-known technologies, and the specific process is not repeated here. The larger the information entropy and the larger the range, the greater the fluctuation of the complexity of the internal elements in the modal sequence, and the more likely it is that the ultrasonic wave will be disturbed during propagation, resulting in the inability to accurately estimate the compressive strength of the concrete, and the greater the acoustic wave interference.

[0054] Step 3: Obtain the interference difference of each measurement position at each collection moment based on the difference in acoustic wave interference between each measurement position and other measurement positions at each collection moment.

[0055] Normally, when there is metal material inside a certain measurement position in concrete, the measurement position is greatly affected by metal interference. The farther away from the measurement position, the smaller the impact of metal interference. At this time, the greater the abnormal difference between the sound wave interference characteristics at the measurement position and the sound wave interference characteristics of other measurement positions, the more it can reflect the characteristics of the measurement position being affected by the metal interference inside the concrete, and the easier it is to judge the accuracy of the concrete compressive strength.

[0056] Further, the interference difference at each acquisition moment at each measurement position is calculated. The specific expression in this embodiment is:

[0057] , where is the interference difference of the sth measurement position at the acquisition time t, is the normalization function, is the number of measurement locations, is the judgment function, when When , the judgment function value is 1, when When , the judgment function value is 0, It is the difference between the acoustic wave interference degree at the collection time t of the s-th measurement position and the acoustic wave interference degree at the collection time t of the v-th measurement position. In this embodiment, the difference between the acoustic wave interference degrees is reflected by taking the absolute value of the difference between the two acoustic wave interference degrees. In actual application scenarios, the implementer may also adopt other calculation methods.

[0058] It can be understood that the greater the difference between the acoustic interference degree at a certain measurement position and the acoustic interference degrees at other measurement positions, the greater the abnormal difference between the acoustic interference characteristics at the measurement position and other measurement positions. At this time, the measurement position is more affected by the interference of the metal inside the concrete, thereby affecting the accuracy of the compressive strength test, and the greater the interference difference.

[0059] Step 4: Cluster the interference differences of the measurement positions at all acquisition times, and obtain the propagation credibility of the ultrasonic wave at each measurement position according to the mean interference difference within each cluster in the clustering results, as well as the difference between each cluster and other clusters regarding the mean interference difference, which is used to divide the measurement position into a reference measurement position and a measurement position to be corrected.

[0060] Since the metal substances inside the concrete have certain spatial distribution characteristics, the measurement position containing metal substances inside the concrete is strongly affected by metal interference, while the measurement position far away from the metal substances is weakly affected by metal interference, or even almost unaffected by metal interference. In general, the interference difference at all acquisition moments at the measurement position is at a low level, and the distribution of the interference difference is relatively concentrated, indicating that the smaller the metal interference at the measurement position, the better the stability of the ultrasonic sound velocity, and the greater the credibility of the ultrasonic sound velocity at the measurement position.

[0061] In order to analyze the reliability of the ultrasonic sound velocity at each measurement position, a data set consisting of the interference differences at all acquisition moments at each measurement position is input into a DPC density peak clustering algorithm (density peak clustering). In this embodiment, the cutoff distance in the DPC density peak clustering algorithm is 1% of the total number of sample points in the data set. The DPC density peak clustering algorithm obtains the clustering results of the corresponding data set at each measurement position. The DPC density peak clustering algorithm is a well-known technology and the specific process will not be repeated here.

[0062] Based on the above analysis, the propagation reliability of ultrasonic waves at each measurement position is calculated:

[0063] , where is the propagation reliability of the ultrasonic wave at the sth measurement position, is an exponential function with a natural constant as the base, Q is the number of clusters in the clustering result corresponding to the sth measurement position, and are the interference difference means of the jth and j-1th clusters in the corresponding clustering results at the sth measurement position. The smaller the interference difference means within the cluster and the smaller the difference in the interference difference means between different clusters, to a certain extent, it shows that the metal interference level in the ultrasonic propagation process at the measurement position is at a low level and the ultrasonic sound velocity has a high stability level, that is, the higher the credibility of ultrasonic propagation at the measurement position, the greater the propagation credibility.

[0064] Furthermore, the propagation credibility of the ultrasonic wave at all measurement positions is counted, and the measurement position corresponding to the maximum propagation credibility is recorded as the reference measurement position, and the remaining measurement positions are recorded as measurement positions to be corrected. The metal interference at the reference measurement position is weak, or even almost unaffected by the metal interference, and the accuracy of its ultrasonic sound velocity is high. Therefore, the ultrasonic sound velocity at the reference measurement position can be used to correct the error of the ultrasonic sound velocity at the remaining measurement positions to be corrected.

[0065] Step 5: By analyzing the numerical difference and directional difference of the ultrasonic sound velocity between each measurement position to be corrected and the reference measurement position, as well as the interference difference of each measurement position to be corrected at each acquisition time, the ultrasonic sound velocity correction value of each measurement position to be corrected at each acquisition time is obtained.

[0066] Generally, the ultrasonic waves in adjacent measurement areas have similar variation characteristics, and the greater the difference in interference at each acquisition moment at the measurement position to be corrected, the greater the influence of metal interference on the acquisition moment, and the greater the coefficient should be used to correct the ultrasonic sound velocity. Therefore, in this embodiment, the difference in interference at each acquisition moment at the measurement position to be corrected is used as a coefficient to achieve error correction of the ultrasonic sound velocity.

[0067] Based on the above analysis, the sound velocity correction value of the ultrasonic wave at each acquisition time at each measurement position to be corrected is calculated. Preferably, in this embodiment, the specific calculation formula is:

[0068] , where is the corrected value of the ultrasonic sound velocity at the i-th measurement position to be corrected at the acquisition time t, , are the ultrasonic sound velocity and interference difference of the i-th measurement position to be corrected at the acquisition time t, is the ultrasonic sound velocity at the reference measurement position at the acquisition time t.

[0069] It should be noted that the difference between the ultrasonic sound velocity at the reference measurement position at the collection time t and the ultrasonic sound velocity at the collection time t at the measurement position to be corrected has direction and magnitude, which characterizes the direction of error correction and the maximum correction distance. At this time, the greater the interference difference at the measurement position to be corrected, the greater the intensity of the error correction, so as to avoid the ultrasonic sound velocity being easily affected by the interference of metal substances inside the concrete, resulting in the problem of inability to accurately infer the compressive strength of the concrete, thereby improving the accuracy of concrete compressive strength detection.

[0070] Step 6: Acquire the representative value of the sound velocity of each measurement position to be corrected in combination with the sound velocity correction value of each measurement position to be corrected at all acquisition times, and the representative value of the sound velocity of each reference measurement position is the average value of the ultrasonic sound velocity of the reference measurement position at all acquisition times; based on the representative value of the sound velocity and the representative value of rebound at each measurement position, obtain the compressive strength of each measurement position of the concrete to be tested.

[0071] The average value of the sound velocity correction value of the ultrasonic wave at all acquisition moments at each measurement position to be corrected is recorded as the representative value of the sound velocity at each measurement position to be corrected, and the average value of the sound velocity of the ultrasonic wave at all acquisition moments at the reference measurement position is recorded as the representative value of the sound velocity at the reference measurement position, so as to obtain the representative value of the sound velocity of each measurement area.

[0072] Furthermore, in order to achieve accurate detection of concrete compressive strength, the representative values ​​of ultrasonic sound velocity and rebound at each standard measurement position of pre-selected concrete will be analyzed, and the compressive strength at each standard measurement position will be obtained through compressive strength test. It should be noted that the measurement data obtained at the standard measurement position has high accuracy, and ultrasonic sound velocity measurement is not interfered by metal and other substances. Therefore, the compressive strength test function is fitted by combining the compressive strength test results at each standard measurement position and the representative values ​​of sound velocity and rebound at each standard measurement position. The specific process is as follows:

[0073] Preferably, in this embodiment, 100 standard measurement positions are artificially preselected in the historically cast steel fiber concrete, wherein the ultrasonic wave is not affected by the interference of metal substances when propagating and measuring the velocity at the standard measurement position, and an ultrasonic detector is used to measure the ultrasonic sound velocity at each standard measurement position at multiple acquisition moments, and a concrete rebound test hammer is used to measure the rebound representative value of each standard measurement position, and the sound velocity representative value of the standard measurement position is the average of the ultrasonic sound velocity at the standard measurement position at all acquisition moments;

[0074] By performing a compressive strength test on each standard measurement position, a standard compressive strength value of each standard measurement position is obtained. Specifically, a failure load is applied to the standard measurement position, where the failure load is the maximum pressure value borne by the concrete at the standard measurement position, and the pressure-bearing area of ​​the standard measurement position where the failure load is applied is obtained. According to the calculation formula of the compressive strength, the ratio of the failure load to the pressure-bearing area where the failure load is applied is calculated as the standard compressive strength of the standard measurement position, wherein the measurement and calculation of the compressive strength are both well-known technologies, and the specific process will not be repeated here.

[0075] The ultrasonic rebound comprehensive method is used to perform nonlinear fitting on the relationship between the standard rebound representative value, the standard sound velocity representative value and the standard compressive strength of all standard measurement positions to obtain a compressive strength function, and the rebound representative value and the sound velocity representative value of each measurement position of the concrete to be tested are input into the compressive strength function to calculate the compressive strength of each measurement position. The ultrasonic rebound comprehensive method and nonlinear fitting are both well-known technologies, and the specific process will not be repeated here.

[0076] So far, the above process according to this embodiment can realize the detection of concrete compressive strength.

[0077] Based on the same inventive concept as the above method, an embodiment of the present application also provides a concrete compressive strength detection system for construction projects, including a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the steps of any one of the above-mentioned methods for detecting the compressive strength of concrete for construction projects are implemented.

[0078] It is to be understood that the sequence of the embodiments of the present application described above is for description only and does not represent the advantages and disadvantages of the embodiments. The above describes specific embodiments of the present specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0079] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0080] The above content is only an implementation method of the present application and is not intended to limit the scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the protection scope of the present application.

Claims

1. A method for testing the compressive strength of concrete for construction engineering, characterized in that: The following steps are involved: Obtaining a rebound representative value at each measuring position of the concrete to be tested and the ultrasonic sound velocity at each acquisition time, wherein the rebound representative value is an average of the rebound values ​​of multiple rebound measuring points at the measuring position; Perform modal decomposition on the ultrasonic sound velocity of all local neighboring moments of each measurement position at each acquisition moment, analyze the range and information entropy of each modal component, and obtain the acoustic interference degree of each measurement position at each acquisition moment; Obtaining the interference difference of each measurement position at each acquisition moment based on the difference in acoustic wave interference between each measurement position and other measurement positions at each acquisition moment; Cluster the interference differences of the measurement positions at all acquisition moments, and obtain the propagation credibility of the ultrasonic wave at each measurement position according to the mean value of the interference differences within each cluster in the clustering result, and the difference between each cluster and other clusters regarding the mean value of the interference differences, so as to divide the measurement positions into reference measurement positions and measurement positions to be corrected; By analyzing the numerical difference and directional difference of the ultrasonic sound velocity between each measurement position to be corrected and the reference measurement position, as well as the interference difference of each measurement position to be corrected at each acquisition time, the sound velocity correction value of the ultrasonic wave at each measurement position to be corrected at each acquisition time is obtained; The representative value of the sound velocity of each measurement position to be corrected is obtained by combining the sound velocity correction value of each measurement position to be corrected at all acquisition times, and the representative value of the sound velocity of each reference measurement position is the average value of the ultrasonic sound velocity of the reference measurement position at all acquisition times; the compressive strength of each measurement position of the concrete to be tested is obtained based on the representative value of the sound velocity and the representative value of rebound at each measurement position; The calculation formula of the acoustic interference degree of each measurement position at each acquisition time is: , where is the acoustic interference degree at the sth measurement position at the acquisition time t, is the modal sequence number of the local sound velocity sequence at the acquisition time t at the sth measurement position, is the information entropy of the ath mode sequence of the local sound velocity sequence at the sth measurement position at the acquisition time t, is the range of the ath modal sequence of the local sound velocity sequence at the acquisition time t at the sth measurement position; wherein the local sound velocity sequence is composed of the ultrasonic sound velocities of all local neighboring moments of the acquisition time t arranged in chronological order, and the local sound velocity sequence is modally decomposed to obtain each modal component, and all elements in each modal component constitute each modal sequence; The calculation formula of the interference difference of each measurement position at each acquisition time is: , where is the interference difference of the sth measurement position at the acquisition time t, is the normalization function, is the number of measurement locations, is the difference between the acoustic interference degree at the acquisition time t of the s-th measurement position and the acoustic interference degree at the acquisition time t of the v-th measurement position, is the judgment function, when When , the judgment function value is 1, when When , the value of the judgment function is 0; The corresponding calculation formula for the propagation credibility of the ultrasonic wave at each measurement position is: , where is the propagation reliability of the ultrasonic wave at the sth measurement position, is an exponential function with a natural constant as the base, Q is the number of clusters in the clustering result corresponding to the sth measurement position, and are the mean values ​​of interference differences of the jth and j-1th clusters in the clustering results corresponding to the sth measurement position; The corresponding calculation formula for the sound velocity correction value of the ultrasonic wave at each acquisition time at each measurement position to be corrected is: , where is the corrected value of the ultrasonic sound velocity at the i-th measurement position to be corrected at the acquisition time t, , are the ultrasonic sound velocity and interference difference of the i-th measurement position to be corrected at the acquisition time t, is the ultrasonic sound velocity at the reference measurement position at the acquisition time t.

2. A method for testing the compressive strength of concrete for construction engineering according to claim 1, characterized in that: All the local neighboring moments of each acquisition moment are a plurality of acquisition moments with the shortest time intervals to each acquisition moment.

3. A method for testing the compressive strength of concrete for construction engineering as claimed in claim 1, characterized in that: The reference measurement positions and the measurement positions to be corrected are further divided as follows: the measurement position corresponding to the maximum propagation credibility is used as the reference measurement position, and the remaining other measurement positions are the measurement positions to be corrected.

4. A method for testing the compressive strength of concrete for construction engineering as claimed in claim 1, characterized in that: The representative value of the sound velocity of each position to be corrected is the average value of the sound velocity correction value of the ultrasonic wave at each measurement position to be corrected at all acquisition moments.

5. A method for testing the compressive strength of concrete for construction engineering according to claim 1, characterized in that: The method of obtaining the compressive strength of each measuring position of the concrete to be tested based on the representative value of the speed of sound and the representative value of the rebound at each measuring position comprises: Preset each standard measurement position in the preselected concrete, obtain the rebound representative value of each standard measurement position, take the average value of the ultrasonic sound velocity of each standard measurement position at all acquisition moments as the sound velocity representative value of each standard measurement position, and obtain the standard compressive strength of each standard position through compressive strength test; The representative rebound values, representative sound velocity values ​​and standard compressive strength of all standard measurement positions are fitted to obtain the compressive strength function, and the compressive strength of each measurement position of the concrete to be tested is calculated.

6. A concrete compressive strength detection system for construction engineering, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 5 are implemented.

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