Method for determining internal damage of test piece after test

Abstract

The embodiment of the invention relates to the technical field of analysis of test materials, in particular to a method for determining internal damage of a test piece after a test, and the method mainly comprises the following steps: measuring X-direction wave velocities and Z-direction wave velocities of a plurality of velocity measurement points on the surface of the test piece; the test piece is tested, the X-direction wave velocity and the Z-direction wave velocity of the velocity measurement point after the test are measured, and the X-direction wave velocity attenuation of the velocity measurement point is determined; determining the relationship between the X-direction wave velocity attenuation of the velocity measurement point and the Z coordinate of the velocity measurement point; determining Z-direction wave velocity attenuation of any point in the test piece according to the relation and the Z-direction wave velocities before and after the test; and determining the internal damage of the test piece according to the Z-direction wave velocity attenuation. According to the embodiment of the invention, by determining the relationship between the X-direction wave velocity attenuation and the Z coordinate and combining the Z-direction wave velocities before and after the test, the Z-direction wave velocity attenuation of any point in the test piece is accurately determined, and then the accurate characterization of the internal damage of the test piece is realized according to the Z-direction wave velocity attenuation.

Description

Technical Field

[0001] Embodiments of the present application relate to the technical field of analyzing and testing materials, and particularly to a method for determining internal damage of a test piece after a test. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] Rocks and concrete are two typical heterogeneous materials. When subjected to external loads, defects will occur inside them, and such defects are defined as internal damage of rocks and concrete. With the rapid development of technologies such as tunnel boring machines (TBMs), rock and concrete tests need to be carried out frequently. However, during the test process, the internal damage of rocks and concrete will continue to accumulate, resulting in a decline in their self-bearing capacity, and ultimately leading to the overall failure of rocks and concrete and the loss of bearing capacity, affecting the stability and safety of underground engineering. Summary of the Invention

[0004] A brief overview of the present application is given below to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description to be presented later.

[0005] In a first aspect, embodiments of the present application provide a method for determining internal damage of a test piece after a test. The method includes the following steps: S10: Set a plurality of velocity measurement points on the surface of the test piece, determine the XYZ coordinates of the plurality of velocity measurement points, and measure the X-direction wave velocity and Z-direction wave velocity of the velocity measurement points; S20: Conduct a test on the test piece, measure the X-direction wave velocity and Z-direction wave velocity of the velocity measurement points after the test, and determine the X-direction wave velocity attenuation of the velocity measurement points; S30: Determine the velocity measurement points with the same XY coordinates on the surface of the test piece; S40: Determine the relationship between the X-direction wave velocity attenuation of the velocity measurement points and the Z coordinates of the velocity measurement points; S50: According to the relationship determined in step S40, as well as the Z-direction wave velocity before the test and the Z-direction wave velocity after the test, determine the Z-direction wave velocity attenuation of any point inside the test piece that is different from the surface of the test piece; S60: Determine the internal damage of the test piece according to the Z-direction wave velocity attenuation.

[0006] In the embodiments of the present application, by determining the velocity measurement points on the surface of the specimen with the same XY coordinates and the X-direction wave velocity attenuation of the velocity measurement points, the non-uniform distribution of damage in the Z direction of the specimen is considered, so as to determine the relationship between the X-direction wave velocity attenuation of the velocity measurement points and the Z coordinate. Moreover, the relationship between the X-direction wave velocity attenuation and the Z coordinate is determined, as well as the connection between the Z-direction wave velocity and the Z-direction wave velocity attenuation of the velocity measurement points before and after the test. Therefore, by measuring the X-direction wave velocity and the Z-direction wave velocity of the velocity measurement points on the surface of the specimen before and after the test, the Z-direction wave velocity attenuation of any point inside the specimen can be accurately determined, and then by using the Z-direction wave velocity attenuation of any point inside the specimen, the accurate characterization of the internal damage of the specimen can be realized.

[0007] In a second aspect, the embodiments of the present application provide a method for determining the internal damage of a specimen after a test. The method includes the following steps: S10: Set a plurality of velocity measurement points on the surface of the specimen, determine the XYZ coordinates of the plurality of velocity measurement points, and measure the X-direction wave velocity, the Z-direction wave velocity, and the Y-direction wave velocity of the velocity measurement points; S20: Conduct a test on the specimen, measure the X-direction wave velocity, the Z-direction wave velocity, and the Y-direction wave velocity of the velocity measurement points after the test, and determine the X-direction wave velocity attenuation of the velocity measurement points; S30: Determine the velocity measurement points on the surface of the specimen with the same XY coordinates; S40: Determine the relationship between the X-direction wave velocity attenuation of the velocity measurement points and the Z coordinate of the velocity measurement points; S50: According to the relationship determined in step S40 and by measuring the Z-direction wave velocity of the velocity measurement points before and after the test, determine the Z-direction wave velocity attenuation of any point inside the specimen that is different from the surface of the specimen; S60: Determine the velocity measurement points on the surface of the specimen with the same XZ coordinates; S70: Determine the relationship between the Z-direction wave velocity attenuation of the velocity measurement points and the Y coordinate of the velocity measurement points; S80: According to the relationship determined in step S70 and by measuring the Y-direction wave velocity of the velocity measurement points before and after the test, determine the Y-direction wave velocity attenuation of any point inside the specimen that is different from the surface of the specimen; S90: Determine the internal damage of the specimen according to the X-direction wave velocity attenuation of the velocity measurement points determined in step S20, the Z-direction wave velocity attenuation of any point inside the specimen determined in step S50, and the Y-direction wave velocity attenuation of any point inside the specimen determined in step S80.

[0008] In the embodiments of the present application, by determining the relationship between the X-direction wave velocity attenuation and the Z coordinate of the velocity measurement point, the Z-direction wave velocity attenuation at any point inside the specimen can be accurately determined. Moreover, after determining the Z-direction wave velocity attenuation at any point inside the specimen, the relationship between the Z-direction wave velocity attenuation and the Y coordinate is further determined, as well as the connection between the relationship between the Z-direction wave velocity attenuation and the Y coordinate and the Y-direction wave velocity and the Y-direction wave velocity attenuation of the velocity measurement point before and after the test. Thus, by only measuring the X-direction wave velocity, Z-direction wave velocity, and Y-direction wave velocity of the velocity measurement point on the surface of the specimen before and after the test, the X-direction wave velocity attenuation, Z-direction wave velocity attenuation, and Y-direction wave velocity attenuation at any point inside the specimen can be accurately determined. Finally, the internal damage of the specimen is characterized by the wave velocity attenuation in three directions, eliminating the measurement blind area of the internal damage and effectively avoiding the problem of missing the internal damage of the specimen caused by the characterization in a single direction, further improving the comprehensiveness and accuracy of the characterization of the internal damage of the specimen. Description of the Drawings

[0009] Other objects and advantages of the present application will become apparent and can help to comprehensively understand the present application through the description of the embodiments of the present application with reference to the drawings below.

[0010] Figure 1 It is a flowchart of a method for determining the internal damage of a specimen after a test according to an embodiment of the first aspect of the present application;

[0011] Figure 2 It is a schematic diagram of the arrangement of the velocity measurement points of a specimen according to an embodiment of the present application;

[0012] Figure 3 It is a schematic diagram of the grouping of the velocity measurement points on the surface of a specimen according to an embodiment of the present application;

[0013] Figure 4 It is a relationship curve diagram of the X-direction wave velocity attenuation of a velocity measurement point and the Z coordinate according to an embodiment of the present application;

[0014] Figure 5 It is a flowchart of a method for determining the internal damage of a specimen after a test according to an embodiment of the second aspect of the present application.

[0015] Description of the Reference Signs:

[0016] 10. Specimen; 11. Velocity measurement point; 12. Rock pillar X1; 13. Rock pillar X2; 14. Rock pillar X k ; 141. Rock block X k L1; 142. Rock block X k L2; 143. Rock block X k L i ; 15. Rock pillar X n ;

[0017] 20. Speed measurement device; 21. Probe; 22. Signal line;

[0018] 30. Relationship curve between X - wave velocity attenuation and Z coordinate.

[0019] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner that does not affect the reader's understanding. Detailed implementation manners

[0020] In the following, exemplary embodiments of the present application will be described in conjunction with the accompanying drawings. For clarity and conciseness, not all features of the actual implementation manners are described in the specification. However, it should be understood that many implementation - specific decisions must be made during the development of any such actual embodiment in order to achieve the developer's specific goals, for example, to comply with those restrictions related to the system and business, and these restrictions may vary with different implementation manners. In addition, it should also be understood that although the development work may be very complex and time - consuming, for those skilled in the art who benefit from the content of the present application, such development work is only a routine task.

[0021] Here, it should also be noted that in order to avoid obscuring the present application with unnecessary details, only the device structures and / or processing steps closely related to the solution according to the present application are shown in the accompanying drawings, while other details less related to the present application are omitted.

[0022] The inventors of the present application have found that currently, the method for determining the internal damage of rock or concrete specimens usually measures the wave velocity attenuation on the upper and lower surfaces of the specimens, and uses the wave velocity - damage formula to convert the measured wave velocity attenuation into a damage distribution map of the specimens. However, this method ignores the non - uniform distribution of damage in the depth direction of the specimens and the spatial region characteristics of the damage caused by the test, resulting in the measurement results being difficult to accurately reflect the actual internal damage of the specimens, and further affecting the determination of the impact degree of the internal damage of the specimens on the project during on - site construction.

[0023] Based on this, the embodiments of the present application provide a method for determining the internal damage of specimens after a test. Figure 1 It is a flowchart of the method for determining the internal damage of specimens after a test according to the first - aspect embodiment of the present application. As Figure 1As shown, the method includes the following steps: S10: Set multiple velocity measurement points on the surface of the specimen, determine the XYZ coordinates of the multiple velocity measurement points, and measure the X-direction wave velocity and Z-direction wave velocity of the velocity measurement points; S20: Conduct a test on the specimen, measure the X-direction wave velocity and Z-direction wave velocity of the velocity measurement points after the test, and determine the X-direction wave velocity attenuation of the velocity measurement points; S30: Determine the velocity measurement points with the same XY coordinates on the surface of the specimen; S40: Determine the relationship between the X-direction wave velocity attenuation of the velocity measurement points and the Z coordinates of the velocity measurement points; S50: According to the relationship determined in step S40, as well as the Z-direction wave velocity before the test and the Z-direction wave velocity after the test, determine the Z-direction wave velocity attenuation of any point inside the specimen that is different from the surface of the specimen; S60: Determine the internal damage of the specimen according to the Z-direction wave velocity attenuation.

[0024] In the embodiments of the present application, by determining the velocity measurement points with the same XY coordinates on the surface of the specimen and the X-direction wave velocity attenuation of the velocity measurement points, the uneven distribution of damage in the Z direction of the specimen is considered, so as to determine the relationship between the X-direction wave velocity attenuation of the velocity measurement points and the Z coordinates. Moreover, the relationship between the X-direction wave velocity attenuation and the Z coordinates is determined in connection with the Z-direction wave velocity and Z-direction wave velocity attenuation of the velocity measurement points before and after the test. Therefore, by measuring the X-direction wave velocity and Z-direction wave velocity of the velocity measurement points on the surface of the specimen before and after the test, the Z-direction wave velocity attenuation of any point inside the specimen can be accurately determined, and then the internal damage of the specimen can be accurately characterized by using the Z-direction wave velocity attenuation of any point inside the specimen.

[0025] In some embodiments, in step S40, the X-direction wave velocity attenuation of the velocity measurement points can be determined according to the X-direction wave velocity of the velocity measurement points and the X-direction wave velocity of the velocity measurement points after the test. Specifically, the X-direction wave velocity of the velocity measurement points, the X-direction wave velocity of the velocity measurement points after the test, and the X-direction wave velocity attenuation of the velocity measurement points conform to the following relational expression:

[0026] R = (V0 - V1) / V0 × 100%.

[0027] Wherein, V1 is the X-direction wave velocity of the velocity measurement points after the test, with the unit of m / s; V0 is the X-direction wave velocity of the velocity measurement points before the test, with the unit of m / s; R is the X-direction wave velocity attenuation of the velocity measurement points, with the unit of %.

[0028] Figure 2 It is a schematic diagram of the layout of the velocity measurement points 11 of the specimen 10 according to the embodiments of the present application. Figure 3 It is a schematic diagram of the grouping of the velocity measurement points 11 on the surface of the specimen 10 according to the embodiments of the present application. As Figure 2 and Figure 3As shown, in some embodiments, in step S40, the velocity measurement points 11 on the surface of the test piece 10 are divided into multiple groups according to the XY coordinates of the velocity measurement points 11, and according to the X-direction wave velocity attenuation of the velocity measurement points 11 in each group and the Z coordinates of the velocity measurement points 11, the relationship between the X-direction wave velocity attenuation and the Z coordinates in each group is determined. Among them, the XY coordinates of the velocity measurement points 11 in the same group are the same. In the embodiments of the present application, by grouping the velocity measurement points 11 on the surface of the test piece 10 and determining the relationship between the X-direction wave velocity attenuation and the Z coordinates in each group, the pertinence of the relationship between the X-direction wave velocity attenuation and the Z coordinates is effectively improved, and it is ensured that the X-direction wave velocity attenuation and the Z coordinates of any point in the same group conform to the determined relationship between the X-direction wave velocity attenuation and the Z coordinates.

[0029] Exemplarily, as Figure 3 shown, the XOY surface of the test piece 10 can be divided into rock pillars X112, rock pillars X213, rock pillars X k 14 and rock pillars X n 15, where the rock blocks X k L1141, rock blocks X k L2142, rock blocks X k L i 143 are in one group.

[0030] In some embodiments, in step S40, the relationship between the X-direction wave velocity attenuation and the Z coordinates in each group can be determined by fitting the X-direction wave velocity attenuation and the Z coordinates of the velocity measurement points 11 in each group, and a relationship curve 30 of the X-direction wave velocity attenuation and the Z coordinates as Figure 4 shown is obtained. Further, the X-direction wave velocity attenuation of any point inside the test piece 10 can be accurately determined through the relationship curve 30 and the relational expression of the X-direction wave velocity attenuation and the Z coordinates. Figure 4 It is a relationship curve diagram of the X-direction wave velocity attenuation and the Z coordinates of the velocity measurement points 11 according to the embodiments of the present application, where the abscissa is the Z coordinate (cm) and the ordinate is the percentage of the X-direction wave velocity attenuation.

[0031] In some embodiments, in step S50, the height of any point i in the Z direction is L i , and according to the height L i , the Z-direction average wave velocity of the velocity measurement points 11, the Z-direction average wave velocity after the test of the velocity measurement points 11, and the relationship determined in step S40, the Z-direction wave velocity attenuation of any point i different from the surface of the test piece 10 inside the test piece 10 is determined.

[0032] In the embodiments of the present application, the height of any point i in the Z direction is the Z coordinate of any point i. Therefore, according to the height L i of any point i in the Z direction and the relationship between the X-direction wave velocity attenuation and the Z coordinates, the X-direction wave velocity attenuation of any point i inside the test piece 10 can be determined.

[0033] In some embodiments, in step S50, the relationship determined in step S40 is set as f(Z), where Z is the value of the Z coordinate and f(Z) is the attenuation of the wave velocity in the X direction. The height L of any point i of the specimen 10 in the Z direction i , the average wave velocity in the Z direction of the velocity measurement point 11, the average wave velocity in the Z direction of the velocity measurement point 11 after the test, and the relationship determined in step S40 comply with the following relational expression:

[0034]

[0035] wherein, V B is the average wave velocity in the Z direction of the velocity measurement point 11 after the test, with the unit of: m / s; L is the height of the specimen 10 in the Z direction, with the unit of: m; L i is the height of any point i in the Z direction, with the unit of: m; L i-1 is the height of the previous point i - 1 of any point i in the Z direction; W i is the percentage of the wave velocity attenuation in the Z direction of any point i, and i takes any integer from 1 to L; V A is the average wave velocity in the Z direction of the velocity measurement point 11 before the test, with the unit of: m / s; K is a coefficient.

[0036] In the embodiments of the present application, based on the conservation of the acoustic wave propagation path time, that is, the sum of the times for the acoustic wave to pass through all the rock blocks in the specimen 10 is equal to the time for the acoustic wave to pass through the specimen 10, the relationship among the height of the specimen 10 in the Z direction, the height difference in the Z direction between any point i and its previous point i - 1, and the wave velocity attenuation in the Z direction of any point i is established. At the same time, according to the relationship between the wave velocity attenuation in the X direction and the Z coordinate, the heights in the Z direction of any point i and its previous point i - 1, and the height of the specimen 10 in the Z direction, the coefficient K affecting the above relationship is determined, so as to ensure the accuracy and reliability of determining the wave velocity attenuation in the Z direction of any point i by using the above relationship.

[0037] In some embodiments, the specimen 10 is set as a hexahedron, and a plurality of velocity measurement points 11 are arranged on each surface, and there is a predetermined distance between the velocity measurement points 11. In the embodiments of the present application, there is a predetermined distance between the velocity measurement points 11 to ensure that when the adjacent velocity measurement points 11 are separated by a predetermined distance, the velocity measurement points 11 can achieve a comprehensive coverage of the specimen 10, eliminate the test blind area, and ensure a high test efficiency.

[0038] It is easy to understand that the larger the predetermined distance between the velocity measurement points 11, the lower the accuracy of the wave velocity measurement on the surface of the specimen 10. Therefore, those skilled in the art can flexibly adjust the predetermined distance between the velocity measurement points 11 according to the actual measurement needs.

[0039] In some embodiments, the predetermined distance is set to be less than or equal to the minimum moving distance of the probe 21 to ensure the accuracy of the measurement results when the adjacent speed measurement points 11 are separated by the predetermined distance. Among them, the minimum moving distance of the probe 21 can be the diameter of the probe 21. Exemplarily, the probe 21 is 5 cm, and the second predetermined distance is set to 5 cm.

[0040] As Figure 2 shown, in some embodiments, the test piece 10 can be set as a cuboid, and the three mutually perpendicular edges of the cuboid are the X-axis, Y-axis, and Z-axis.

[0041] In some embodiments, in step S10, it further includes polishing the surface of the test piece 10 to reduce the flatness of the surface of the test piece 10, thereby further improving the tightness of the fit between the speed measurement device 20 and the surface of the speed measurement point 11. In some preferred embodiments, the flatness is set to be less than 0.02 mm to ensure that at this flatness, the speed measurement device 20 can be closely attached to the speed measurement point 11.

[0042] In some embodiments, the speed measurement points 11 arranged on two opposite surfaces are arranged on the same axis and parallel to the normal of the two opposite surfaces, so that the sound wave passes through the test piece 10 along the shortest path. At this time, the distance between the two opposite surfaces is the displacement of the sound wave in the test piece 10, which simplifies the determination step of the sound wave displacement in the test piece 10. Moreover, when measuring the wave speed in the same direction using this arrangement method, the displacement of the sound wave in the test piece 10 is the same, thereby simplifying the wave speed calculation of the speed measurement points 11 in the same direction.

[0043] In some embodiments, a speed measurement signal can be emitted to the speed measurement point 11 on one of the two opposite surfaces, and the speed measurement signal can be received at the corresponding speed measurement point 11 on the opposite surface. It is easy to understand that the time difference between emitting the speed measurement signal and receiving the speed measurement signal is the time for the sound wave to pass through the test piece 10. Furthermore, through the time for the sound wave to pass through the test piece 10 and the displacement of the sound wave passing through the test piece 10, the wave speed of the speed measurement point 11 can be determined.

[0044] In some embodiments, the speed measurement signal can be a sound wave.

[0045] In some embodiments, during speed measurement, the speed measurement device 20 is set to be in close contact with the surface of the speed measurement point 11 to eliminate the interference of the air medium between the speed measurement device 20 and the speed measurement point 11, ensure that the sound wave can be effectively transmitted between the speed measurement point 11 and the speed measurement device 20, and further improve the accuracy of the X-direction wave speed and Z-direction wave speed of the speed measurement point 11 before and after the measurement test.

[0046] In some embodiments, the speed measurement device 20 is attached to the surface of the speed measurement point 11 through two probes 21. Specifically, the two probes 21 of the speed measurement device 20 are respectively arranged on the speed measurement points 11 on two opposite surfaces. In some embodiments, the two probes 21 can be a transmitting probe and a receiving probe, wherein the transmitting probe is configured to transmit a speed measurement signal, and the receiving probe is configured to receive the speed measurement signal.

[0047] In some embodiments, an ultrasonic coupling agent can be applied to the surfaces of the transmitting probe and the receiving probe, so as to further improve the tightness of the attachment between the transmitting probe and the receiving probe and the surface of the speed measurement point 11 during the wave speed measurement process, eliminate the gap between the transmitting probe and the receiving probe and the surface of the speed measurement point 11, and ensure the accuracy of the wave speed measurement of the speed measurement device 20.

[0048] Since rock or concrete specimens 10 usually need to be subjected to multiple tests or secondary tests, in order to ensure that the measurement of the internal damage of the specimens 10 does not affect their subsequent tests, it is necessary to perform non-destructive testing on the internal damage of the specimens 10. In some embodiments, the speed measurement device 20 can be a rock ultrasonic detector. The rock ultrasonic detector has the advantages of being convenient, efficient, and not causing damage to the specimens 10. Therefore, the non-destructive detection of the internal damage of the specimens 10 can be realized by using the rock ultrasonic detector, so that it is not necessary to perform core sampling on the specimens 10, and the risk of secondary damage to the specimens 10 caused by the core sampling process is eliminated.

[0049] In some embodiments, in step S20, it also includes setting parameters such as the gain, frequency, delay time, and standard sample calibration of the rock ultrasonic detector to improve the accuracy of the wave speed measurement of the rock ultrasonic detector. Among them, the setting of parameters such as the gain, frequency, delay time, and standard sample calibration of the rock ultrasonic detector can be determined by those skilled in the art according to experience.

[0050] In some embodiments, the test is a blasting, laser, or temperature test, and after the test is completed, the specimen 10 is intact and the rock surface has no large-area spalling.

[0051] In the embodiments of the present application, the test can be a blasting, laser, or temperature test to respectively simulate the presplitting blasting treatment, laser pretreatment, and temperature pretreatment in on-site construction. Moreover, ensuring that the specimen 10 is intact and the rock surface has no large-area spalling can prevent the speed measurement device 20 from being difficult to be attached to the surface of the speed measurement point 11 due to large-area shedding of the rock surface. At the same time, it can avoid the influence of the fragmentation of the specimen 10 on the measurement accuracy of the X-direction wave speed and Z-direction wave speed of the speed measurement point 11 after the test.

[0052] In some embodiments, in step S20, after the velocity measurement points 11 on each pair of surfaces are tested, the velocity measurement points 11 on the next pair of surfaces are tested, so as to avoid repeatedly switching the surfaces where the velocity measurement device 20 is in contact with the velocity measurement points 11 during the test, thereby improving the velocity measurement efficiency of the velocity measurement points 11.

[0053] In some embodiments, during velocity measurement, after a stable waveform appears in the wave velocity measured by the test device, the emission of the velocity measurement signal is stopped and recorded as the measurement value to ensure the stability and reliability of the measurement value.

[0054] In some embodiments, the measurement value can be the amplitude, frequency of the waveform, and the time for the sound wave to pass through the test piece 10, so that the wave velocity of the velocity measurement point 11 can be determined according to the time for the sound wave to pass through the test piece 10 and the displacement of the sound wave in the test piece 10.

[0055] In some embodiments, in step S60, it further includes: repeating steps S40 - S50 to determine the Z - direction wave velocity attenuation distribution inside the test piece 10, constructing a Z - direction spatial damage map of the test piece 10 according to the Z - direction wave velocity attenuation distribution, and then realizing the corresponding analysis between the test result data and the damage of the test piece 10 according to the Z - direction spatial damage map.

[0056] In some embodiments, the relationship between wave velocity attenuation and damage degree can be utilized to convert the Z - direction wave velocity attenuation into Z - direction spatial damage. Specifically, the wave velocity attenuation and the damage degree conform to the following expression:

[0057] D = 1 - (1 - N) 2 。

[0058] N = (V0 - V1) / V0×100%.

[0059] Wherein, D is the damage degree, N is the wave velocity attenuation, and the unit is: %.

[0060] The inventors of the present application found that the internal defects of the rock and concrete test pieces 10 are directional, and the sound wave conducts along the most complete structural body in the test piece 10. Therefore, when the sound wave conduction direction is the same as the crack surface direction, the existence of internal defects in the test piece 10 cannot be detected, and it is difficult to comprehensively and accurately reflect the internal damage of the test piece 10.

[0061] Based on this, the embodiments of the present application further provide a method for determining the internal damage of the test piece 10 after the test. Figure 5 It is a flowchart of the method for determining the internal damage of the test piece 10 after the test according to the embodiments of the second aspect of the present application. As Figure 5As shown, the method includes the following steps: S10: Set a plurality of velocity measurement points 11 on the surface of the specimen 10, determine the XYZ coordinates of the plurality of velocity measurement points 11, and measure the wave velocity in the X direction, the wave velocity in the Z direction, and the wave velocity in the Y direction of the velocity measurement points 11; S20: Conduct a test on the specimen 10, measure the wave velocity in the X direction, the wave velocity in the Z direction, and the wave velocity in the Y direction of the velocity measurement points 11 after the test, and determine the attenuation of the wave velocity in the X direction of the velocity measurement points 11;

[0062] S30: Determine the velocity measurement points 11 with the same XY coordinates on the surface of the specimen 10; S40: Determine the relationship between the attenuation of the wave velocity in the X direction of the velocity measurement points 11 and the Z coordinates of the velocity measurement points 11; S50: According to the relationship determined in step S40, measure the wave velocity in the Z direction of the velocity measurement points 11 before and after the test, and determine the attenuation of the wave velocity in the Z direction of any point inside the specimen 10 that is different from the surface of the specimen 10; S60: Determine the velocity measurement points 11 with the same XZ coordinates on the surface of the specimen 10; S70: Determine the relationship between the attenuation of the wave velocity in the Z direction of the velocity measurement points 11 and the Y coordinates of the velocity measurement points 11; S80: According to the relationship determined in step S70, measure the wave velocity in the Y direction of the velocity measurement points 11 before and after the test, and determine the attenuation of the wave velocity in the Y direction of any point inside the specimen 10 that is different from the surface of the specimen 10; S90: According to the attenuation of the wave velocity in the X direction of the velocity measurement points 11 determined in step S20, the attenuation of the wave velocity in the Z direction of any point inside the specimen 10 determined in step S50, and the attenuation of the wave velocity in the Y direction of any point inside the specimen 10 determined in step S80, determine the internal damage of the specimen 10.

[0063] In the embodiment of the present application, by determining the relationship between the attenuation of the wave velocity in the X direction and the Z coordinates of the velocity measurement points, the attenuation of the wave velocity in the X direction of any point inside the specimen 10 can be accurately determined. Moreover, after determining the attenuation of the wave velocity in the Z direction of any point inside the specimen 10, the relationship between the attenuation of the wave velocity in the Z direction and the Y coordinates, as well as the connection between the relationship between the attenuation of the wave velocity in the Z direction and the Y coordinates and the wave velocity in the Y direction and the attenuation of the wave velocity in the Y direction of the velocity measurement points 11 before and after the test, are further determined. Thus, by only measuring the wave velocity in the X direction, the wave velocity in the Z direction, and the wave velocity in the Y direction of the velocity measurement points 11 on the surface of the specimen 10 before and after the test, the attenuation of the wave velocity in the X direction, the attenuation of the wave velocity in the Z direction, and the attenuation of the wave velocity in the Y direction of any point inside the specimen 10 can be accurately determined; finally, the internal damage of the specimen 10 is characterized by using the wave velocity attenuation in three directions, eliminating the measurement blind area of the internal damage, effectively avoiding the problem of omission of the internal damage of the specimen 10 caused by single-direction characterization, and further improving the comprehensiveness and accuracy of the characterization of the internal damage of the specimen 10.

[0064] In some embodiments, in step S40, the X-direction wave velocity attenuation of the velocity measurement point 11 can be determined according to the X-direction wave velocity of the velocity measurement point 11 and the X-direction wave velocity of the velocity measurement point 11 after the test. Specifically, the X-direction wave velocity of the velocity measurement point 11, the X-direction wave velocity of the velocity measurement point 11 after the test, and the X-direction wave velocity attenuation of the velocity measurement point 11 conform to the following relational expression:

[0065] R = (V0 - V1) / V0×100%.

[0066] Wherein, V1 is the X-direction wave velocity of the velocity measurement point 11 after the test, with the unit of m / s; V0 is the X-direction wave velocity of the velocity measurement point 11 before the test, with the unit of m / s; R is the X-direction wave velocity attenuation of the velocity measurement point 11, with the unit of %.

[0067] As Figure 2 and Figure 3 shown, in some embodiments, in step S40, the velocity measurement point 11 is divided into multiple groups according to the XY coordinates of the velocity measurement point 11 on the surface of the test piece 10, and the relationship between the X-direction wave velocity attenuation and the Z coordinate of each group of velocity measurement points 11 is determined according to the X-direction wave velocity attenuation and the Z coordinate of the velocity measurement point 11 in each group. Among them, the XY coordinates of the velocity measurement points 11 in the same group are the same. In the embodiments of the present application, by grouping the velocity measurement points 11 on the surface of the test piece 10 and determining the relationship between the X-direction wave velocity attenuation and the Z coordinate of each group, the pertinence of the relationship between the X-direction wave velocity attenuation and the Z coordinate is effectively improved, and it is ensured that the X-direction wave velocity attenuation and the Z coordinate of any point in the same group conform to the determined relationship between the X-direction wave velocity attenuation and the Z coordinate.

[0068] Exemplarily, as Figure 3 shown, the XOY surface of the test piece 10 can be divided into rock columns X112, rock columns X213, rock columns X k 14 and rock columns X n 15, wherein, rock blocks X k L1141, rock blocks X k L2142, rock blocks X k L i 143 are in one group.

[0069] In some embodiments, in step S40, the relationship between the X-direction wave velocity attenuation and the Z coordinate of each group can be determined by fitting the X-direction wave velocity attenuation and the Z coordinate of the velocity measurement point 11 in each group, and a relationship curve 30 of the X-direction wave velocity attenuation and the Z coordinate as Figure 4 shown is obtained. Further, the X-direction wave velocity attenuation of any point inside the test piece 10 can be accurately determined through the relationship curve 30 of the X-direction wave velocity attenuation and the Z coordinate and the relational expression. Figure 4It is a relationship curve graph of the X - direction wave speed attenuation of the speed measurement point 11 and the Z - coordinate according to an embodiment of the present application. Among them, the abscissa is the Z - coordinate (cm), and the ordinate is the percentage of X - direction wave speed attenuation.

[0070] In some embodiments, in step S50, the height of any point i in the Z - direction is L i , according to the height L i , the Z - direction wave speed attenuation of any point i inside the specimen 10 different from the surface of the specimen 10 is determined based on the height L, the average Z - direction wave speed of the speed measurement point 11, the average Z - direction wave speed of the speed measurement point 11 after the test, and the relationship determined in step S40.

[0071] In an embodiment of the present application, the height of any point i in the Z - direction is the Z - coordinate of any point i. Therefore, according to the height L of any point i in the Z - direction i and the relationship between the X - direction wave speed attenuation and the Z - coordinate, the X - direction wave speed attenuation of any point i inside the specimen 10 can be determined, and then the X - direction wave speed attenuation distribution inside the specimen 10 can be determined.

[0072] In some embodiments, in step S50, the relationship determined in step S40 is set as f(Z), where Z is the value of the Z - coordinate, f(Z) is the X - direction wave speed attenuation, the height L of any point i of the specimen 10 in the Z - direction i , the average Z - direction wave speed of the speed measurement point 11, the average Z - direction wave speed of the speed measurement point 11 after the test, and the relationship determined in step S40 conform to the following relational formula:

[0073]

[0074] Among them, V B is the average Z - direction wave speed of the speed measurement point 11 after the test, and the unit is: m / s; L is the Z - direction height of the specimen 10, and the unit is: m; L i is the Z - direction height of any point i, and the unit is: m; L i-1 is the Z - direction height of the previous point i - 1 of any point i; W i is the percentage of Z - direction wave speed attenuation of any point i, and i takes any integer from 1 to L; V A is the average Z - direction wave speed of the speed measurement point 11 before the test, and the unit is: m / s; K is a coefficient.

[0075] In the embodiments of the present application, based on the conservation of the time of the acoustic wave propagation path, that is, the sum of the times for the acoustic wave to pass through all the rock blocks in the specimen 10 is equal to the time for the acoustic wave to pass through the specimen 10, the relationship among the Z-direction height of the specimen 10, the Z-direction height difference between any point i and the previous point i-1, and the Z-direction wave velocity attenuation at any point i is established. At the same time, according to the relationship between the X-direction wave velocity attenuation and the Z coordinate, the Z-direction heights of any point i and its previous point i-1, and the Z-direction height of the specimen 10, the coefficient K affecting the above relationship is determined, so as to ensure the accuracy and reliability of determining the Z-direction wave velocity attenuation at any point i using the above relationship.

[0076] In some embodiments, in step S70, according to the XZ coordinates of the velocity measurement points 11 on the surface of the specimen 10, the velocity measurement points 11 are divided into multiple groups, and according to the Z-direction wave velocity attenuation of all the velocity measurement points 11 in each group and the Y coordinate of the velocity measurement points 11, the relationship between the Z-direction wave velocity attenuation and the Y coordinate of each group is determined. Among them, the XZ coordinates of the velocity measurement points 11 in the same group are the same. In the embodiments of the present application, by grouping the velocity measurement points 11 on the surface of the specimen 10 and determining the relationship between the Z-direction wave velocity attenuation and the Y coordinate of each group, it is ensured that the Z-direction wave velocity attenuation and the Y coordinate of any point in the same group conform to the determined relationship between the Z-direction wave velocity attenuation and the Y coordinate, thereby improving the pertinence and reliability of the determined relationship between the Z-direction wave velocity attenuation and the Y coordinate.

[0077] In some embodiments, in step S70, the relationship between the Z-direction wave velocity attenuation and the Y coordinate of each group can be determined by fitting the Z-direction wave velocity attenuation and the Y coordinate of the velocity measurement points 11 in each group. In the embodiments of the present application, by fitting the Z-direction wave velocity attenuation and the Y coordinate of the velocity measurement points 11 in each group, the relationship curve and relationship formula between the Z-direction wave velocity attenuation and the Y coordinate of each group are obtained, and then the Y-direction wave velocity attenuation of any point inside the specimen 10 can be accurately determined according to the relationship curve and relationship formula.

[0078] In some embodiments, in step S80, the height of any point i in the Y direction is M i , and according to the height M i , the Y-direction average wave velocity of the velocity measurement points 11, the Y-direction average wave velocity after the test of the velocity measurement points 11, and the relationship determined in step S70, the Y-direction wave velocity attenuation of any point i inside the specimen 10 different from the surface of the specimen 10 is determined.

[0079] In the embodiments of the present application, the height of any point i in the Y direction is the Y coordinate of any point i. Therefore, according to the height M of any point i in the Y direction i and the relationship between the Z-direction wave velocity attenuation and the Y coordinate, the Z-direction wave velocity attenuation of any point i inside the specimen 10 can be determined.

[0080] In some embodiments, in step S80, the relationship determined in step S70 is set as f(Y), where Y is the value of the Y coordinate and f(Y) is the attenuation of the wave velocity in the Z direction. The height M of any point i in the Y direction i The average wave velocity in the Y direction of the velocity measurement point 11, the average wave velocity in the Y direction after the test of the velocity measurement point 11, and the relationship determined in step S70 comply with the following relational expression:

[0081]

[0082]

[0083] where V D is the average wave velocity in the Y direction after the test of the velocity measurement point 11, with the unit of m / s; M is the height of the specimen 10 in the Y direction, with the unit of m; M i is the height of any point i in the Y direction, with the unit of m; M i-1 is the height of the previous point i - 1 of any point i in the Y direction; W i is the percentage of the wave velocity attenuation in the Y direction of any point i; i takes any integer from 1 to M; V C is the average wave velocity in the Y direction before the test of the velocity measurement point 11, with the unit of m / s; H is a coefficient.

[0084] In the embodiments of the present application, based on the conservation of the acoustic wave propagation path time, that is, the sum of the times for the acoustic wave to pass through all the rock blocks in the specimen 10 is equal to the time for the acoustic wave to pass through the specimen 10, the relationship among the height of the specimen 10 in the Y direction, the height difference in the Y direction between any point i and its previous point i - 1, and the wave velocity attenuation in the Y direction of any point i is established. At the same time, according to the relationship between the wave velocity attenuation in the Z direction and the Y coordinate, the heights in the Y direction of any point i and its previous point i - 1, and the height of the specimen 10 in the Y direction, the coefficient H affecting the above relationship is determined, so as to ensure the accuracy and reliability of determining the wave velocity attenuation in the Y direction of any point i using the above relationship.

[0085] In some embodiments, the specimen 10 is set as a hexahedron, and a plurality of velocity measurement points 11 are arranged on each surface, and there is a predetermined distance between the velocity measurement points 11. In the embodiments of the present application, there is a predetermined distance between the velocity measurement points 11 to ensure that when the adjacent velocity measurement points 11 are separated by a predetermined distance, the velocity measurement points 11 can achieve a comprehensive coverage of the specimen 10, eliminate the test blind area, and ensure a high test efficiency.

[0086] It is easy to understand that the larger the predetermined distance between the velocity measurement points 11, the lower the accuracy of the wave velocity measurement on the surface of the specimen 10. Therefore, those skilled in the art can flexibly adjust the predetermined distance between the velocity measurement points 11 according to the actual measurement needs.

[0087] In some embodiments, the predetermined distance is set to be less than or equal to the minimum moving distance of the probe 21 to ensure the accuracy of the measurement results when the adjacent speed measurement points 11 are separated by the predetermined distance. Among them, the minimum moving distance of the probe 21 can be the diameter of the probe 21. Exemplarily, the probe 21 is 5 cm and the second predetermined distance is set to 5 cm.

[0088] As Figure 2 shown, in some embodiments, the test piece 10 can be set as a cuboid, and the three mutually perpendicular edges of the cuboid are the X-axis, Y-axis, and Z-axis.

[0089] In some embodiments, in step S10, it further includes polishing the surface of the test piece 10 to reduce the flatness of the surface of the test piece 10, thereby further improving the tightness of the fit between the speed measurement device 20 and the surface of the speed measurement point 11. In some preferred embodiments, the flatness is set to be less than 0.02 mm to ensure that at this flatness, the speed measurement device 20 can be closely attached to the speed measurement point 11.

[0090] In some embodiments, the speed measurement points 11 arranged on two opposite surfaces are arranged on the same axis and parallel to the normal of the two opposite surfaces, so that the sound wave passes through the test piece 10 along the shortest path. At this time, the distance between the two opposite surfaces is the displacement of the sound wave in the test piece 10, which simplifies the determination step of the sound wave displacement in the test piece 10. Moreover, when using this arrangement method to measure the wave speed in the same direction, the displacement of the sound wave in the test piece 10 is the same, thereby simplifying the wave speed calculation of the speed measurement points 11 in the same direction.

[0091] In some embodiments, a speed measurement signal can be transmitted to the speed measurement points 11 on one of the two opposite surfaces, and the speed measurement signal can be received at the corresponding speed measurement points 11 on the opposite surface. It is easy to understand that the time difference between transmitting the speed measurement signal and receiving the speed measurement signal is the time for the sound wave to pass through the test piece 10. Furthermore, by the time for the sound wave to pass through the test piece 10 and the displacement of the sound wave passing through the test piece 10, the wave speed of the speed measurement point 11 can be determined.

[0092] In some embodiments, the speed measurement signal can be a sound wave.

[0093] In some embodiments, during speed measurement, the speed measurement device 20 is set to be in close contact with the surface of the speed measurement point 11 to eliminate the interference of the air medium between the speed measurement device 20 and the speed measurement point 11, ensure that the sound wave can be effectively transmitted between the speed measurement point 11 and the speed measurement device 20, and further improve the accuracy of the X-direction wave speed, Z-direction wave speed, and Y-direction wave speed of the speed measurement point 11 before and after the measurement test.

[0094] In some embodiments, the velocity measurement device 20 is attached to the surface of the velocity measurement point 11 through two probes 21. Specifically, the two probes 21 of the velocity measurement device 20 are respectively arranged on the velocity measurement points 11 of two opposite surfaces. In some embodiments, the two probes 21 can be a transmitting probe and a receiving probe, wherein the transmitting probe is configured to transmit a velocity measurement signal, and the receiving probe is configured to receive the velocity measurement signal.

[0095] In some embodiments, an ultrasonic coupling agent can be applied to the surfaces of the transmitting probe and the receiving probe, so as to further improve the tightness of the attachment between the transmitting probe and the receiving probe and the surface of the velocity measurement point 11 during the wave velocity measurement process, eliminate the gap between the transmitting probe and the receiving probe and the surface of the velocity measurement point 11, and ensure the accuracy of the wave velocity measurement of the velocity measurement device 20.

[0096] Since rock or concrete specimens 10 usually need to be subjected to multiple tests or secondary tests, in order to ensure that the measurement of internal damage to the specimens 10 does not affect their subsequent tests, it is necessary to perform non-destructive testing on the internal damage of the specimens 10. In some embodiments, the velocity measurement device 20 can be a rock ultrasonic detector. The rock ultrasonic detector has the advantages of being convenient, efficient, and not causing damage to the specimens 10. Therefore, the non-destructive detection of the internal damage of the specimens 10 can be realized by using the rock ultrasonic detector, so that there is no need to perform core sampling on the specimens 10, and the risk of secondary damage to the specimens 10 caused by the core sampling process is eliminated.

[0097] In some embodiments, in step S20, it further includes setting parameters such as the gain, frequency, delay time, and standard sample calibration of the rock ultrasonic detector to improve the accuracy of the wave velocity measurement of the rock ultrasonic detector. Among them, the setting of parameters such as the gain, frequency, delay time, and standard sample calibration of the rock ultrasonic detector can be determined by those skilled in the art according to experience.

[0098] In some embodiments, the test is a blasting, laser, or temperature test, and after the test is completed, the specimen 10 is intact and there is no large-area spalling on the rock surface.

[0099] In the embodiments of the present application, the test can be a blasting, laser, or temperature test to respectively simulate the presplitting blasting treatment, laser pretreatment, and temperature pretreatment in on-site construction. And ensuring that the specimen 10 is intact and there is no large-area spalling on the rock surface can prevent the velocity measurement device 20 from being difficult to be attached to the surface of the velocity measurement point 11 due to large-area shedding of the rock surface. At the same time, it can avoid the influence of the fragmentation of the specimen 10 on the measurement accuracy of the X-direction wave velocity, Z-direction wave velocity, and Y-direction wave velocity of the velocity measurement point 11 after the test.

[0100] In some embodiments, in step S20, after the speed measurement points 11 on each pair of surfaces are tested, the speed measurement points 11 on the next pair of surfaces are tested, so as to avoid repeatedly switching the surfaces where the speed measurement device 20 is in contact with the speed measurement points 11 during the test, thereby improving the speed measurement efficiency of the speed measurement points 11.

[0101] In some embodiments, during speed measurement, after a stable waveform appears in the wave speed measured by the test device, the emission of the speed measurement signal is stopped and recorded as the measured value to ensure the stability and reliability of the measured value.

[0102] In some embodiments, the measured value can be the amplitude and frequency of the waveform and the time for the sound wave to pass through the test piece 10, so that the wave speed of the speed measurement point 11 can be determined according to the time for the sound wave to pass through the test piece 10 and the displacement of the sound wave in the test piece 10.

[0103] In some embodiments, in step S60, it further includes: repeating steps S40 - S50 to determine the Z - direction wave speed attenuation distribution inside the test piece 10, constructing a Z - direction spatial damage map of the test piece 10 according to the Z - direction wave speed attenuation distribution, and then realizing the corresponding analysis of the test result data and the damage of the test piece 10 according to the Z - direction spatial damage map.

[0104] In some embodiments, in step S90, the difference processing can be performed on the Y - direction wave speed attenuation by using calculation software, so as to further improve the accuracy of the Y - direction wave speed attenuation data. Specifically, for the difference processing of the Y - direction wave speed attenuation, those skilled in the art can complete it according to experience.

[0105] In some embodiments, in step S90, it further includes: repeating steps S70 - S80 to determine the Y - direction wave speed attenuation distribution inside the test piece 10, constructing a three - dimensional spatial damage map of the test piece 10 according to the X - direction wave speed attenuation distribution, Z - direction wave speed attenuation distribution and Y - direction wave speed attenuation distribution inside the test piece 10, and then realizing the corresponding analysis of the test result data and the damage of the test piece 10 according to the three - dimensional spatial damage map of the test piece 10.

[0106] In some embodiments, the relationship between wave speed attenuation and damage degree can be utilized to convert the Z - direction wave speed attenuation into Z - direction spatial damage. Specifically, the wave speed attenuation and damage degree conform to the following expression:

[0107] D = 1 - (1 - N) 2 .

[0108] Where D is the damage degree and N is the wave speed attenuation, and the unit is: %.

[0109] In some embodiments, in step S90, it further includes: comparing the X-direction wave velocity attenuation distribution, Z-direction wave velocity attenuation distribution, and Y-direction wave velocity attenuation distribution inside the specimen 10 to determine all internal damages of the specimen 10 and their directions.

[0110] The following uses specific examples to further illustrate the process of using the method for determining the internal damage of the specimen 10 after the test provided in the first aspect of the present application.

[0111] The specimen 10 is made into a cuboid, and the X-axis, Y-axis, and Z-axis of the specimen 10 are determined. The surface of the specimen 10 is polished. After the surface of the specimen 10 is polished, a velocity measurement point 11 is arranged every 5 cm on the six surfaces of the specimen 10, and it is ensured that the velocity measurement points 11 arranged on two opposite surfaces are arranged on the same axis and parallel to the normal of the two opposite surfaces.

[0112] Set the parameters of the rock ultrasonic detector and calibrate the rock ultrasonic detector. Connect the calibrated rock ultrasonic detector to the transmitting probe and receiving probe through the signal line 22, apply ultrasonic coupling agent on the surfaces of the transmitting probe and receiving probe, and connect the transmitting probe and receiving probe to the velocity measurement point 11 on the ZOY surface and the velocity measurement point 11 on the surface opposite to the ZOY surface respectively. Start the rock ultrasonic detector, the transmitting probe emits sound waves to the velocity measurement point 11, the receiving probe receives the sound waves transmitted by the velocity measurement point 11, stop the sound wave emission after the rock ultrasonic detector shows a stable waveform, and record the wave velocity V0 in the X-direction before the test. After all the velocity measurement points 11 on the ZOY surface are tested, transfer to the XOY surface and the surface opposite to the XOY surface and repeat the above steps to obtain the wave velocity V in the Z-direction before the test A 。

[0113] Perform micro-blasting, laser, or temperature tests on the specimen 10 and ensure that the specimen 10 is intact and there is no large-area spalling on the rock surface. After that, measure the wave velocities of the velocity measurement points 11 on the ZOY surface and the surface opposite to the ZOY surface according to the same steps, and record the wave velocity in the X-direction after the test at the same measurement point as V1. After all the velocity measurement points 11 on the ZOY surface are tested, transfer to the XOY surface and the surface opposite to the XOY surface and repeat the above steps to obtain the wave velocity in the Z-direction after the test at the same measurement point and record it as V B 。Calculate the X-direction wave velocity attenuation of the velocity measurement point 11 according to the wave velocity V0 in the X-direction before the test and the wave velocity V1 in the X-direction after the test at the same measurement point.

[0114] Divide the velocity measurement points 11 into multiple groups according to the XY coordinates of the velocity measurement points 11 on the surface of the specimen 10, and the XY coordinates of each group are the same. Fit the X-direction wave velocity attenuation and Z coordinates of all measurement points in each group to obtain the relationship curve and relationship formula of the X-direction wave velocity attenuation and Z coordinates of each group.

[0115] Based on the relationship curve and formula between the X - direction wave velocity attenuation and the Z - coordinate of the group to which any point i belongs, and the Z - direction average wave velocities before and after the test at the velocity measurement point 11 with the same XY coordinates as any point i, determine the Z - direction wave velocity attenuation of any point i. Repeat the above steps to obtain the Z - direction wave velocity attenuation distribution inside the test piece 10.

[0116] Based on the Z - direction wave velocity attenuation distribution inside the test piece 10, establish the spatial damage in the Z - direction inside the test piece 10, and determine the internal damage of the test piece 10 after the test according to the spatial damage.

[0117] The following uses a specific example to further illustrate the process of using the method provided in the second aspect of this application to determine the internal damage of the test piece 10 after the test.

[0118] Manufacture the test piece 10 into a cuboid, and determine the X - axis, Y - axis, and Z - axis of the test piece 10. Polish the surface of the test piece 10. After the surface of the test piece 10 is polished, arrange a velocity measurement point 11 every 5 cm on the six surfaces of the test piece 10, and ensure that the velocity measurement points 11 arranged on two opposite surfaces are on the same axis and parallel to the normal of the two opposite surfaces.

[0119] Set the parameters of the rock ultrasonic detector and calibrate the rock ultrasonic detector. Connect the calibrated rock ultrasonic detector to the transmitting probe and the receiving probe through the signal line 22, apply ultrasonic coupling agent on the surfaces of the transmitting probe and the receiving probe, and connect the transmitting probe and the receiving probe to the velocity measurement point 11 on the ZOY surface and the velocity measurement point 11 on the surface opposite to the ZOY surface respectively. Start the rock ultrasonic detector, the transmitting probe emits sound waves to the velocity measurement point 11, the receiving probe receives the sound waves transmitted by the velocity measurement point 11, stop the sound wave emission after the rock ultrasonic detector shows a stable waveform, and record the wave velocity V0 in the X - direction before the test. After all the velocity measurement points 11 on the ZOY surface are tested, sequentially transfer to the XOY surface and the surface opposite to the XOY surface and the XOZ surface and the surface opposite to the XOZ surface, and repeat the above steps to obtain the wave velocity V in the Z - direction before the test A and the wave velocity V in the Y - direction before the test C .

[0120] Conduct a micro - blasting, laser, or temperature test on the test piece 10, and ensure that the test piece 10 is intact and there is no large - area spalling on the rock surface. After that, measure the wave velocities of the velocity measurement points 11 on the ZOY surface and the surface opposite to the ZOY surface according to the same steps, and record the wave velocity V1 in the X - direction after the test at the same measurement points. After all the velocity measurement points 11 on the ZOY surface are tested, sequentially transfer to the XOY surface and the surface opposite to the XOY surface and the XOZ surface and the surface opposite to the XOZ surface, and repeat the above steps to obtain the wave velocity V in the Z - direction after the test at the same measurement points B and the wave velocity V in the Y - direction after the testD Calculate the X - direction wave velocity attenuation based on the wave velocity V0 in the X - direction before the X - direction test and the wave velocity V1 in the X - direction after the test at the same measuring point.

[0121] Divide the velocity measuring points 11 on the surface of the test piece 10 into multiple groups according to the XY coordinates of the velocity measuring points 11, and the XY coordinates of each group are the same. Fit the X - direction wave velocity attenuation and the Z - coordinate of all measuring points in each group to obtain the relationship curve and relationship formula between the X - direction wave velocity attenuation and the Z - coordinate of each group. Determine the XYZ coordinates of any point i inside the test piece 10 and determine the group to which any point i belongs. According to the relationship curve and relationship formula between the X - direction wave velocity attenuation and the Z - coordinate of the group to which any point i belongs, determine the X - direction wave velocity attenuation of any point i. Repeat the above steps to determine the distribution of the X - direction wave velocity attenuation inside the test piece.

[0122] Determine the Z - direction wave velocity attenuation of any point i according to the relationship curve and relationship formula between the X - direction wave velocity attenuation and the Z - coordinate of the group to which any point i belongs and the average wave velocities in the Z - direction before and after the test of the velocity measuring points 11 with the same XY coordinates as any point i. Repeat the above steps to obtain the distribution of the Z - direction wave velocity attenuation inside the test piece 10.

[0123] Divide the velocity measuring points 11 on the surface of the test piece 10 into multiple groups according to the XZ coordinates of the velocity measuring points 11, and make the XZ coordinates of each group the same. Fit the Z - direction wave velocity attenuation and the Y - coordinate of all measuring points in each group to obtain the relationship curve and relationship formula between the Z - direction wave velocity attenuation and the Y - coordinate of each group.

[0124] Determine the Y - direction wave velocity attenuation of any point i according to the relationship curve and relationship formula between the Z - direction wave velocity attenuation and the Y - coordinate of the group to which any point i belongs and the average wave velocities in the Y - direction before and after the test of the velocity measuring points 11 with the same XZ coordinates as any point i. Repeat the above steps to obtain the distribution of the Y - direction wave velocity attenuation inside the test piece 10.

[0125] Based on the distribution of the X - direction wave velocity attenuation, the Z - direction wave velocity attenuation, and the Y - direction wave velocity attenuation inside the test piece 10, establish a three - dimensional space damage model inside the test piece 10, and compare the Y - direction wave velocity attenuation of all points inside the test piece 10 with the X - direction wave velocity attenuation and the Z - direction wave velocity attenuation to determine all internal damages and their directions of the test piece 10.

[0126] For the embodiments of the present application, it should also be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0127] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for determining internal damage of a test piece after a test, characterized in that, S10: Set a plurality of velocity measurement points on the surface of the test piece, determine the XYZ coordinates of the plurality of velocity measurement points, and measure the X-direction wave velocity and Z-direction wave velocity of the velocity measurement points; S20: Conduct a test on the test piece, measure the X-direction wave velocity, Z-direction wave velocity of the velocity measurement points after the test, and determine the X-direction wave velocity attenuation of the velocity measurement points; S30: Determine the velocity measurement points with the same XY coordinates on the surface of the test piece; S40: Determine the relationship between the X-direction wave velocity attenuation of the velocity measurement points and the Z coordinate of the velocity measurement points; S50: According to the relationship determined in step S40, the Z-direction wave velocity before the test and the Z-direction wave velocity after the test, determine the Z-direction wave velocity attenuation of any point inside the test piece different from the surface of the test piece; S60: Determine the internal damage of the test piece according to the Z-direction wave velocity attenuation.

2. A method for determining internal damage of a test piece after a test, characterized in that, S10: Set a plurality of velocity measurement points on the surface of the test piece, determine the XYZ coordinates of the plurality of velocity measurement points, and measure the X-direction wave velocity, Z-direction wave velocity and Y-direction wave velocity of the velocity measurement points; S20: Conduct a test on the test piece, measure the X-direction wave velocity, Z-direction wave velocity and Y-direction wave velocity of the velocity measurement points after the test, and determine the X-direction wave velocity attenuation of the velocity measurement points; S30: Determine the velocity measurement points with the same XY coordinates on the surface of the test piece; S40: Determine the relationship between the X-direction wave velocity attenuation of the velocity measurement points and the Z coordinate of the velocity measurement points; S50: According to the relationship determined in step S40, measure the Z-direction wave velocity of the velocity measurement points before and after the test, and determine the Z-direction wave velocity attenuation of any point inside the test piece different from the surface of the test piece; S60: Determine the velocity measurement points with the same XZ coordinates on the surface of the test piece; S70: Determine the relationship between the Z-direction wave velocity attenuation of the velocity measurement points and the Y coordinate of the velocity measurement points; S80: According to the relationship determined in step S70, measure the Y-direction wave velocity of the velocity measurement points before and after the test, and determine the Y-direction wave velocity attenuation of any point inside the test piece different from the surface of the test piece; S90: Determine the internal damage of the test piece according to the X-direction wave velocity attenuation of the velocity measurement points determined in step S20, the Z-direction wave velocity attenuation of any point inside the test piece determined in step S50, and the Y-direction wave velocity attenuation of any point inside the test piece determined in step S80.

3. The method according to claim 1 or 2, characterized in that, In step S50, the height of any point i in the Z direction is L i , According to the height L i , the Z-direction average wave velocity before the test at the velocity measurement point, the Z-direction average wave velocity after the test at the velocity measurement point, and the relationship determined in step S40, determine the Z-direction wave velocity attenuation of any point i inside the test piece that is different from the surface of the test piece.

4. The method according to claim 3, characterized in that In step S50, The relationship determined in step S40 is set as f(Z), Z is the value of the Z coordinate, and f(Z) is the X-direction wave velocity attenuation, The height L of any point i in the Z direction i , the average wave velocity in the Z direction of the velocity measurement point, the average wave velocity in the Z direction after the test of the velocity measurement point, and the relationship determined in step S40 conform to the following relational expression: Among them, V B is the average Z - direction wave velocity after the test at the velocity measurement point, with the unit of m / s; L is the Z - direction height of the specimen, with the unit of m; L i is the Z - direction height of any point i, with the unit of m; L i-1 is the Z - direction height of the previous point i - 1 of any point i, with the unit of m; W i is the percentage of Z - direction wave velocity attenuation at any point i; i takes any integer from 1 to L; V A is the average Z - direction wave velocity before the test at the velocity measurement point, with the unit of m / s; K is a coefficient.

5. The method according to claim 1 or 2, characterized in that, Among them, The test piece is set as a hexahedron, and a plurality of velocity measurement points are set on each surface, and a predetermined distance is provided between the velocity measurement points.

6. The method according to claim 5, characterized in that, The velocity measurement points set on two opposite surfaces are arranged on the same axis and parallel to the normal of the two opposite surfaces.

7. The method according to claim 1 or 2, characterized in that, When measuring the velocity, the velocity measuring device is set to fit the surface of the velocity measuring point.

8. The method according to claim 1 or 2, characterized in that the test is a blasting, laser or temperature test, and after the test is completed, the test piece is intact and there is no large-area spalling on the rock surface.

9. The method according to claim 1 or 2, characterized in that in step S20, after the velocity measuring points on each pair of surfaces are tested, the velocity measuring points on the next pair of surfaces are tested.

10. The method according to claim 9, characterized in that when measuring the velocity, after a stable waveform appears in the wave velocity measured by the measuring device, the emission of the velocity measuring signal is stopped and recorded as the measured value.

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