CN117929121A - Surrounding rock similar material crack and displacement evolution measurement method - Google Patents
Surrounding rock similar material crack and displacement evolution measurement method Download PDFInfo
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- CN117929121A CN117929121A CN202410093985.0A CN202410093985A CN117929121A CN 117929121 A CN117929121 A CN 117929121A CN 202410093985 A CN202410093985 A CN 202410093985A CN 117929121 A CN117929121 A CN 117929121A
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- 239000000463 material Substances 0.000 title claims abstract description 46
- 239000011435 rock Substances 0.000 title claims abstract description 36
- 238000006073 displacement reaction Methods 0.000 title claims abstract description 27
- 238000000691 measurement method Methods 0.000 title description 2
- 238000000034 method Methods 0.000 claims abstract description 40
- 238000012545 processing Methods 0.000 claims abstract description 35
- 238000012360 testing method Methods 0.000 claims abstract description 31
- 238000012669 compression test Methods 0.000 claims abstract description 29
- 238000011068 loading method Methods 0.000 claims abstract description 23
- 230000001502 supplementing effect Effects 0.000 claims abstract description 9
- 238000004519 manufacturing process Methods 0.000 claims abstract description 4
- 238000004458 analytical method Methods 0.000 claims description 18
- 239000013598 vector Substances 0.000 claims description 16
- 239000003973 paint Substances 0.000 claims description 14
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- 239000011159 matrix material Substances 0.000 claims description 3
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- 230000003247 decreasing effect Effects 0.000 claims description 2
- 238000005259 measurement Methods 0.000 claims description 2
- 238000000917 particle-image velocimetry Methods 0.000 abstract description 22
- 238000012544 monitoring process Methods 0.000 abstract description 8
- 238000005516 engineering process Methods 0.000 abstract description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 13
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 description 8
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- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 description 8
- 239000011230 binding agent Substances 0.000 description 4
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical group O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical group [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 2
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- 239000007787 solid Substances 0.000 description 2
- 208000010392 Bone Fractures Diseases 0.000 description 1
- 206010017076 Fracture Diseases 0.000 description 1
- 208000013201 Stress fracture Diseases 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
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Abstract
The invention provides a method for measuring crack and displacement evolution of surrounding rock similar materials, which comprises the following steps: manufacturing a surrounding rock similar material to obtain a compression test sample; adjusting instrument parameters; the instrument comprises an RMT pressure tester, a sea health vision industrial camera and a light supplementing lamp; starting a loading test, stopping loading until the compression test sample is broken greatly or the displacement-stress curve is suddenly reduced downwards, and finishing all the compression test samples; analyzing by adopting a PIV image processing system to obtain image data; and processing the image data and analyzing the result. The PIV image processing system of the particle image velocimetry technology can radically solve the problem, and the monitoring of the test is completed on the basis of not damaging surrounding rock similar materials.
Description
Technical Field
The invention belongs to the technical field of image processing, and particularly relates to a method for measuring crack and displacement evolution of a surrounding rock similar material.
Background
In uniaxial compression tests of similar materials of surrounding rock, the similar materials deform and break due to the load. Deformation and damage occurring in the process are two different stages of similar material morphology change under load. In the deformation stage, local micro-cracks can be formed, and the local micro-cracks are not dominant, but are a main factor for forming non-recoverable deformation; as the load increases, the portion of localized failure increases as the deformation progresses further, and the micro-fracture progresses to an overall macroscopic failure. In the test process, a visual method is often used for measuring the crack length, the crack length is generally required to be read in an interrupted test, and the crack length is inconvenient to observe and has high error possibility; for a harder surrounding rock similar material, a clamp-type extensometer is adopted to detect crack opening displacement, and the crack opening displacement is directly contacted with a test piece when in use, and the dislocation of a holding position is added, so that the vibration of the test piece can influence the calibration precision; the non-contact video extensometer generated according to the image processing technology has the problem that the non-contact video extensometer cannot acquire in real time.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for measuring crack and displacement evolution of a surrounding rock similar material, in particular to a method and a system for processing PIV images and multi-view stereoscopic vision software MVS (Multiple View Stereo), which are combined, and the method is approximately as follows: the method comprises the steps of monitoring a uniaxial compression test of a surrounding rock similar material by an industrial camera, and calculating a speed vector of a shot image by a PIV image processing system, so that the crack generation and evolution process of the surrounding rock similar material during loading is analyzed.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a method for measuring crack and displacement evolution of a surrounding rock similar material, the method comprising:
Manufacturing a surrounding rock similar material to obtain a compression test sample;
Adjusting instrument parameters; the instrument comprises an RMT pressure tester, a sea health vision industrial camera and a light supplementing lamp; the RMT pressure testing machine is used for applying load to the test and recording the change conditions of sample displacement, stress and strain in the loading process in real time; the sea-health vision industrial camera is used in combination with multi-view stereoscopic vision software MVS, and after relevant parameters are adjusted, the test can be monitored in real time; the light supplementing lamp can ensure that the monitoring surface is sufficient in illumination, and is convenient for test and data acquisition;
starting a loading test, stopping loading until the compression test sample is broken greatly or the displacement-stress curve is suddenly reduced downwards, and finishing all the compression test samples;
analyzing by adopting a PIV image processing system to obtain image data;
and processing the image data and analyzing the result.
Further, the surrounding rock similar material adopted by the invention takes IV-grade surrounding rock as a simulation object, wherein the composition of the formulated weak surrounding rock similar material comprises aggregate, binder and regulator; the aggregate comprises coarse aggregate and fine aggregate; the coarse aggregate is quartz sand; the fine aggregate is barite; the binder is fly ash; the regulator is 15W40 engine oil and rosin alcohol solution.
Further, the rosin alcohol solution in the regulator adopted by the invention is prepared by crushing solid gum rosin into particles, and then mixing the particles according to the mass volume ratio of 1g: the gum rosin was fully dissolved in an alcohol solution at a ratio of 3mL, and the volume fraction of ethanol in the alcohol solution was 98%.
Further, the specific steps for obtaining the compression test sample are as follows:
a1 Designing uniaxial compression test schemes with different proportions according to the composition of the surrounding rock similar materials;
a2 According to the uniaxial compression test scheme obtained in the step a 1), accurately weighing materials used in each uniaxial compression test scheme, mixing and uniformly stirring, layering and compacting in a standard mould, demoulding after the sample is formed, and drying to obtain a compression test sample.
Furthermore, in order to better monitor the evolution of cracks and displacement of the sample in the loading process, the analysis and the treatment of images are convenient, and the paint spraying treatment can be carried out on the sample after alcohol in the sample is completely volatilized, and the matte white paint and the matte black paint are alternately used.
Further, the instrument parameters include: setting loading speed in an RMT pressure testing machine, and adjusting aperture and focusing ring of the sea-health industrial camera; setting sampling frequency, gain and exposure time in multi-view stereoscopic vision software MVS; and adjusting the position and the brightness of the light supplementing lamp.
Further, the PIV image processing system is adopted for analysis specifically:
1) The method comprises the steps of importing images acquired by multi-view stereoscopic vision software MVS into a PIV image processing system, selecting an area to be analyzed in the images, calibrating test parameters, inputting the length of a sample, the distance of calibration pixel points and the time corresponding to two image sequences into the PIV image processing system, and calculating the corresponding actual length of each pixel point;
2) The histogram equalization and the high-pass filtering are applied to enhance the image contrast and inhibit the low-frequency information;
3) When an analysis method is selected, a direct cross-correlation calculation method DCC and a fast Fourier transform FFT are selected;
4) When the size of the window is selected, ensuring that the number of particles in each window is 5-25, each particle number is 3-5 pixels, and the same particle is still in the integral window after a time interval, selecting one channel for analysis, or selecting a plurality of channels for analysis, wherein each channel comprises two windows, and ensuring that the sizes of the two windows of the channels are equal or decreasing;
5) After the pretreatment is completed, clicking in the PIV image processing system to start analysis;
6) After the image analysis is completed, the post-processing operation in the PIV image processing system is started, the vectors in the analysis result are verified, all the vectors are placed on a scatter diagram, the region with concentrated vectors in the scatter diagram is selected, error points which are far away from the region on the scatter diagram are deleted, and the post-processing operation is applied to all the images and data are stored.
Further, processing the image data, importing the stored PIV data into Origin software in a matrix form, drawing a contour map according to the time sequence of the sampled image, and analyzing the evolution and the expansion of cracks.
The invention has the technical effects that:
1) The non-contact measurement, the general measuring equipment requires that the measuring sensor is attached to the surface of the sample (attached with a strain gauge) or embedded into the sample (prefabricated small sample), thus having a certain influence on the related mechanical properties of the surrounding rock similar material and the generation and evolution of cracks;
2) The damage form in the test process can be measured instantaneously or monitored in real time, and a common measuring device can only test the displacement vector of a certain point at a certain moment, so that a large number of sensors are required for testing the whole surface. The PIV image processing system of the particle image velocimetry technology can measure the average vector and the instantaneous vector;
3) According to the invention, the surface of the sample is subjected to calibration treatment by adopting two kinds of paint spraying, so that the contrast ratio in the monitoring range can be increased, and the acquisition precision in the test process can be improved conveniently in the loading process.
Drawings
The accompanying drawings illustrate various embodiments by way of example in general and not by way of limitation, and together with the description and claims serve to explain the inventive embodiments. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Such embodiments are illustrative and not intended to be exhaustive or exclusive of the present apparatus or method.
FIG. 1 shows a schematic flow chart of a method for measuring crack and displacement evolution of a surrounding rock similar material according to the invention;
FIG. 2 shows a stress-strain curve diagram of a fifth set of samples according to the present invention;
fig. 3 shows an image presentation at five stages in an embodiment of the invention.
Detailed Description
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
The embodiment aims to solve the defects in the prior art, and provides a measuring method for monitoring loading cracks and displacement evolution of surrounding rock similar materials through particle image velocimetry, in particular to a measuring method for monitoring loading cracks and displacement evolution of surrounding rock similar materials through real-time shooting of an industrial camera and speed vector calculation of images through a PIV image processing system, so that the process of generating and evolving cracks of the surrounding rock similar materials in the loading process is analyzed. As shown in fig. 1, the image processing method suitable for crack detection of the present embodiment includes the steps of:
1) Manufacturing a surrounding rock similar material; preliminary screening of the weak surrounding rock similar materials to obtain a planned weak surrounding rock similar material; the composition of the prepared weak surrounding rock similar material comprises aggregate, binder and regulator; the aggregate comprises coarse aggregate and fine aggregate; the coarse aggregate is quartz sand; the fine aggregate is barite; the binder is fly ash; the regulator is 15W40 engine oil and rosin alcohol solution.
The rosin alcohol solution in the regulator is prepared by crushing solid gum rosin into particles, and then mixing the particles according to the mass volume ratio of 1g: the gum rosin was fully dissolved in an alcohol solution at a ratio of 3mL, and the volume fraction of ethanol in the alcohol solution was 98%.
The specific implementation mode of the uniaxial compression test of the proposed weak surrounding rock similar material in the step 1) adopted by the invention is as follows:
a1 According to the composition of the similar materials of the planned weak surrounding rock, designing uniaxial compression test schemes with different proportions;
a2 Accurately weighing materials used in each single-axis compression test scheme according to the single-axis compression test scheme obtained in the step a 1), mixing and stirring uniformly, putting the materials into a standard mold with 50mm and 100mm for layered compaction, demolding after the sample is molded, and drying the materials in a dryer for 8 hours to obtain a compression test sample;
In order to better monitor the evolution of cracks and displacement of the sample in the loading process, the processing and analysis of images are facilitated, and paint spraying treatment can be carried out on the sample by adopting paint spraying after a surrounding rock similar material test is prepared.
As described above, the invention adopts the alternative use of matte white paint and matte black paint, and comprises the following specific steps: and a smoother surface of the sample is selected, firstly, matte white paint is sprayed to serve as a base color, then, a small amount of matte black paint is uniformly sprayed to serve as a standard point, the contrast in a monitoring range is increased, and the acquisition precision in the test process is improved.
2) Adjusting instrument parameters; the instrument comprises an RMT pressure tester, a sea health vision industrial camera and a light supplementing lamp. The RMT pressure testing machine is used for applying load to the test and recording displacement, stress and strain change conditions of the sample in the loading process in real time;
The sea-health vision industrial camera is connected with the multi-view stereoscopic vision software MVS and can monitor the test in real time after adjusting related parameters;
The light supplementing lamp can ensure that the monitoring surface is sufficient in illumination, and is convenient for test and data acquisition;
The equipment parameters comprise that the loading speed in an RMT pressure testing machine is set to be 0.1mm/min, a large aperture is selected by a sea-health industrial camera, and a focusing ring is manually adjusted until an image is clear; setting the sampling frequency in multi-view stereoscopic vision software MVS as 10Hz, adjusting gain until the sharpness value reaches the maximum, exposing time as 50ms and the like; and adjusting the position and the brightness of the light supplementing lamp to ensure that the image illumination is uniform and no shadow exists.
3) Starting a loading test, setting the loading speed of an RMT pressure tester to be 0.1mm/min, selecting a continuous acquisition mode by multi-view stereoscopic vision software MVS, and stopping loading until a compression test sample is subjected to larger fracture or a displacement-stress curve is suddenly reduced downwards, until all the compression test samples are completed;
4) The PIV image processing system analysis is started, and the specific implementation method is as follows:
in order to better describe the processing and analysis of images according to the present invention, the present invention will be described with a fifth set of similar materials as specific examples.
The image is selected, referring to fig. 2, a stress-strain curve is drawn according to the stress and strain change rule in the loading process, five stages of before peak value, after peak value, before complete damage and complete damage are divided on the curve, the corresponding stress is 60% peak stress, 100% peak stress, 60% peak stress, 20% peak stress and 10% peak stress, 50-60 images before and after each stage are selected, each image is subjected to comparison processing at intervals of 1s, and soil deformation fields in the crack development process are analyzed and displacement vector images are generated.
A1 The image acquired by the multi-view stereoscopic vision software is imported into the PIV image processing system, the area to be analyzed in the image is selected, test parameters are calibrated, the length of a sample, the distance of calibration pixel points and the time corresponding to two image sequences can be input into the software, and the corresponding actual length of each pixel point can be calculated;
a2 Selecting histogram equalization and high-pass filtering in the image processing mode, wherein the enabling window size setting for histogram equalization is divided into 20 pixels and the enabling filter core size for high-pass filtering is set to 15 pixels;
a3 In the analysis method, a Fast Fourier Transform (FFT) is selected, and the image information is converted to a frequency domain for analysis;
a4 Selecting a multi-channel calculation mode when the size of an analysis window is selected, and setting two channels, wherein for the first channel, the size of a first window is 16 pixels, and the size of a second window is 8 pixels; for the second channel, the size of the first window is 8 pixels, and the size of the second window is 4 pixels;
a5 After the pretreatment is completed, clicking in the PIV image processing system to start analysis;
a6 After the PIV system image analysis is completed, the post-processing operation in the PIV image processing system is started, the region with dense vector distribution in the vector diagram is selected, the vector in the region is optimized, the concentrated distribution diagram of the vector can be finally obtained, and the post-processing operation is applied to all images and data are stored.
5) Processing image data, importing the stored PIV data into Origin software in a matrix form, drawing a contour map according to the time sequence of sampling images, and analyzing the evolution and the expansion of cracks.
Referring to fig. 3, five sets of images are processed according to an embodiment of the present invention, in which a contour map on the left side is a displacement change curve obtained by Origin, two corresponding industrial cameras on the right side capture images during loading, the left contour map is generated by comparing the first two images of each set of images, the right contour map is generated by comparing the second two images of each set of images, and as can be seen from the graph, for the same set of data, the displacement change becomes more obvious with the passage of time, and the displacement change is substantially consistent with the phenomenon observed in reality.
The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical solution of the present invention and the inventive concept thereof, and should be covered by the scope of the present invention.
Claims (7)
1. The method for measuring crack and displacement evolution of similar surrounding rock materials is characterized by comprising the following steps:
Manufacturing a surrounding rock similar material to obtain a compression test sample;
adjusting instrument parameters; wherein, the instrument adopts an RMT pressure tester, a sea health vision industrial camera and a light supplementing lamp;
starting a loading test, stopping loading until the compression test sample is broken greatly or the displacement-stress curve is suddenly reduced downwards, and finishing all the compression test samples;
Analyzing the test process by adopting a PIV image processing system to obtain image data;
and processing the image data and analyzing the result.
2. The method for crack and displacement evolution measurement of a surrounding rock-like material of claim 1, wherein the surrounding rock-like material is a class IV surrounding rock.
3. The method for measuring crack and displacement evolution of surrounding rock similar materials according to claim 1, wherein the specific steps of obtaining a compression test sample are as follows:
a1 Designing uniaxial compression test schemes with different proportions according to the composition of the surrounding rock similar materials;
a2 According to the uniaxial compression test scheme obtained in the step a 1), accurately weighing materials used in each uniaxial compression test scheme, mixing and uniformly stirring, layering and compacting in a standard mould, demoulding after the sample is formed, and drying to obtain a compression test sample.
4. The method for measuring crack and displacement evolution of surrounding rock similar materials according to claim 1, wherein the sample is subjected to paint spraying treatment after a compression test sample is obtained, and the paint spraying comprises matte white paint and matte black paint.
5. The method for measuring crack and displacement evolution of surrounding rock-like materials according to claim 1, wherein the instrument parameters include: setting loading speed in an RMT pressure testing machine, and adjusting aperture and focusing ring of the sea-health industrial camera; setting sampling frequency, gain and exposure time in multi-view stereoscopic vision software MVS; and adjusting the position and the brightness of the light supplementing lamp.
6. The method for measuring crack and displacement evolution of surrounding rock similar materials according to claim 1, wherein the step of analyzing the test process by using the PIV image processing system to obtain image data comprises the following steps:
1) The method comprises the steps of importing images acquired by multi-view stereoscopic vision software MVS into a PIV image processing system, selecting an area to be analyzed in the images, calibrating test parameters, inputting the length of a sample, the distance of calibration pixel points and the time corresponding to two image sequences into the PIV image processing system, and calculating the corresponding actual length of each pixel point;
2) The histogram equalization and the high-pass filtering are applied to enhance the image contrast and inhibit the low-frequency information;
3) When an analysis method is selected, a direct cross-correlation calculation method DCC and a fast Fourier transform FFT are selected;
4) When the size of the window is selected, ensuring that the number of particles in each window is 5-25, each particle number is 3-5 pixels, and the same particle is still in the integral window after a time interval, selecting one or more channels for analysis, wherein each channel comprises two windows, and ensuring that the sizes of the two windows of the channels are equal or decreasing;
5) After the pretreatment is completed, clicking in the PIV image processing system to start analysis;
6) After the image analysis is completed, the post-processing operation in the PIV image processing system is started, the vectors in the analysis result are verified, all the vectors are placed on a scatter diagram, the region with concentrated vectors in the scatter diagram is selected, error points which are far away from the region on the scatter diagram are deleted, and the post-processing operation is applied to all the images and data are stored.
7. The method for measuring crack and displacement evolution of surrounding rock-like material according to claim 1, wherein the processing the image data and analyzing the result specifically comprises: processing image data, importing the stored PIV data into Origin software in a matrix form, drawing a contour map according to the time sequence of sampling images, and analyzing the evolution and the expansion of cracks.
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