Method and device for determining dependent variable of loaded coal rock test piece and electronic equipment

Abstract

The invention provides a method and device for determining the dependent variable of a loaded coal rock test piece and electronic equipment, and the method comprises the steps: obtaining a coal rock test piece, a first scanning image of the coal rock test piece in an unloaded state, and a plurality of second scanning images of the coal rock test piece in a continuous load state, thereby obtaining a dependent variable of the coal rock test piece for any second scanning image; according to the second scanning image and the first scanning image, determining the accurate displacement of each voxel in the second scanning image, and then according to the accurate displacement of each voxel in the second scanning image and the position of each voxel in the second scanning image in the first scanning image, determining the accurate displacement of each voxel in the second scanning image; and determining the dependent variable of the corresponding point of the coal rock test piece in the load state corresponding to the second scanning image. Therefore, the CT technology and the DVC technology can be combined to determine the dependent variable of any point of the loaded coal rock test piece in the corresponding load state, and the accuracy and reliability of dependent variable determination are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of coal and rock technology, and in particular to a method, apparatus, and electronic device for determining the strain of a loaded coal and rock specimen. Background Technology

[0002] Rockburst is a sudden and violent destructive force phenomenon caused by the instantaneous release of the elastic deformation energy accumulated in coal (rock) around a coal mine tunnel or working face. In the prevention and control of rockburst disasters, for coal and rock with a strong rockburst tendency, this non-uniform characteristic and internal interactions lead to an extremely complex energy distribution state inside the coal and rock under mining stress. The energy distribution state inside the coal and rock plays a key role in evaluating or predicting the mechanical behavior of coal and rock. To obtain the energy distribution inside loaded coal and rock, it is often necessary to solve for the strain of the loaded coal and rock specimen. Therefore, how to accurately and reliably determine the strain of loaded coal and rock specimens is worthy of study. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, the first objective of this invention is to propose a method for determining the strain of a loaded coal and rock specimen, which combines CT (Computed Tomography) technology with DVC (Digital Volume Correlation) technology to determine the strain at any point of the loaded coal and rock specimen under the corresponding load state, thereby improving the accuracy and reliability of strain determination.

[0005] The second objective of this invention is to provide a device for determining the strain of a loaded coal and rock specimen.

[0006] The third objective of this invention is to provide an electronic device.

[0007] The fourth objective of this invention is to provide a computer-readable storage medium.

[0008] The fifth objective of this invention is to provide a computer program product.

[0009] To achieve the above objectives, a first aspect of the present invention provides a method for determining the strain of a loaded coal and rock specimen, comprising:

[0010] Acquire a coal and rock specimen and a first scan image of the coal and rock specimen under an unloaded state, as well as multiple second scan images of the coal and rock specimen under a continuous load state;

[0011] For any second scan image, determine the precise displacement of each voxel in the second scan image based on the second scan image and the first scan image;

[0012] Based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image in the first scan image, the strain of the corresponding point of the coal and rock specimen under the load state corresponding to the second scan image is determined.

[0013] To achieve the above objectives, a second aspect of the present invention provides an apparatus for determining the strain of a loaded coal and rock specimen, comprising:

[0014] The acquisition module is used to acquire a coal and rock specimen and a first scan image of the coal and rock specimen in an unloaded state, as well as multiple second scan images of the coal and rock specimen in a continuous load state;

[0015] The first determining module is used to determine the precise displacement of each voxel in any second scan image based on the second scan image and the first scan image;

[0016] The second determining module is used to determine the strain of the corresponding point of the coal and rock specimen under the load state corresponding to the second scan image based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image in the first scan image.

[0017] To achieve the above objectives, a third aspect of the present invention provides an electronic device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the aforementioned method for determining the strain of a loaded coal and rock specimen according to the first aspect.

[0018] To achieve the above objectives, a fourth aspect of the present invention provides a computer-readable storage medium storing computer instructions for causing the computer to execute the method for determining the strain of a loaded coal and rock specimen as described in the first aspect.

[0019] To achieve the above objectives, a fifth aspect of the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the method for determining the strain of a loaded coal and rock specimen as described in the first aspect.

[0020] The technical solutions provided by the embodiments of the present invention have the following beneficial effects:

[0021] By acquiring a coal and rock specimen and a first scan image of the specimen under unloaded conditions, as well as multiple second scan images of the specimen under continuous load conditions, the precise displacement of each voxel in any second scan image is determined based on the second and first scan images. Furthermore, based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image within the first scan image, the strain of the corresponding point on the coal and rock specimen under the corresponding load condition in the second scan image is determined. Therefore, by combining CT and DVC techniques, the strain of any point on a loaded coal and rock specimen under a corresponding load condition can be determined, effectively improving the accuracy and reliability of strain determination.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0024] Figure 1 This is a flowchart illustrating a method for determining the strain of a loaded coal and rock specimen according to an embodiment of the present invention.

[0025] Figure 2 This is a flowchart illustrating another method for determining the strain of a loaded coal and rock specimen provided in an embodiment of the present invention.

[0026] Figure 3 This is a flowchart illustrating a method for determining the strain of a loaded coal and rock specimen under a given scenario, as provided in an embodiment of the present invention.

[0027] Figure 4 A schematic diagram showing the results of a device for determining the strain of a loaded coal and rock specimen provided in an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] Over the past few decades, X-ray computed tomography (CT) technology has been successfully applied to the study of coal and rock materials, allowing for non-destructive observation of the internal material properties in three dimensions. However, these methods focus on visualizing the distribution of primary fractures within coal and rock at the microscopic and mesoscopic scales using their scanning imaging principles and three-dimensional reconstruction techniques, without addressing the determination of internal strain variables throughout the entire loading process of coal and rock.

[0031] DVC technology can quantitatively compare CT images of any sample before and after induced changes. Currently, DVC technology has been successfully applied to detect strain fields in artificial composite materials such as concrete and layered rocks, but its application in determining strain variables inside coal and rock, especially strongly impacted coal and rock, under load is relatively limited.

[0032] Therefore, embodiments of the present invention provide a method for determining the strain of loaded coal and rock specimens, so as to combine CT technology and DVC technology to determine the strain of any point of the loaded coal and rock specimen under the corresponding load state, thereby improving the accuracy and reliability of strain determination.

[0033] The following description, with reference to the accompanying drawings, describes a method, apparatus, and electronic device for determining the strain of a loaded coal and rock specimen according to embodiments of the present invention.

[0034] Figure 1 This is a flowchart illustrating a method for determining the strain of a loaded coal and rock specimen according to an embodiment of the present invention.

[0035] like Figure 1 As shown, the method for determining the strain of the loaded coal and rock specimen includes the following steps:

[0036] Step 101: Obtain the coal and rock specimen and a first scan image of the coal and rock specimen under unloaded conditions, as well as multiple second scan images of the coal and rock specimen under continuous load conditions.

[0037] The coal and rock specimens can be from any coal and rock area to be studied. In this embodiment, the specifications of the coal and rock specimens are not limited and can be set arbitrarily, such as φ50mm×100mm, where φ represents the diameter of the circle, × represents multiplication, and connects the two values ​​of diameter and thickness. φ50mm×100mm means a cylindrical object with a diameter of 50 mm and a thickness of 100 mm, and so on.

[0038] Optionally, the following steps can be used to obtain the coal and rock specimen and a first scan image of the coal and rock specimen in an unloaded state, as well as multiple second scan images of the coal and rock specimen under continuous load:

[0039] Step 1011: Obtain sampling samples in the area to be studied using a preset sampling method, and process the sampling samples according to preset specimen specifications to obtain coal and rock specimens.

[0040] The area to be studied can be any coal and rock region, and this embodiment does not impose any restrictions on it.

[0041] The preset sampling method can be any sampling method; that is, this embodiment does not limit the setting of the preset sampling method. Optionally, the preset sampling method can be set based on human experience. For example, the preset sampling method can be set as a sampling method for drilling rock cores or a sampling method for test blocks. Alternatively, the preset sampling method can be dynamically adjusted according to actual application needs. This embodiment does not limit this.

[0042] Optionally, sampling samples can be obtained in the area to be studied by core drilling or test block sampling, wherein the diameter of the core drilling meets a preset threshold condition, and the specifications of the test block meet a preset specification condition.

[0043] The preset threshold and preset specification conditions can be arbitrary; that is, this embodiment does not limit the setting of the preset threshold and preset specification conditions. Optionally, the preset threshold and preset specification conditions can be set based on human experience. For example, the preset threshold condition can be set to be greater than 70mm, in which case, the diameter of the drilled core meeting the preset threshold condition means that the diameter of the drilled core is greater than 70mm; the preset specification condition can be set to be greater than 250mm×250mm×250mm, in which case, the specification of the test block meeting the preset specification condition means that the specification of the test block is greater than 250mm×250mm×250mm. Alternatively, the preset threshold and preset specification conditions can be dynamically adjusted according to actual application needs, which is not limited in this embodiment.

[0044] The preset specimen specifications can be any specifications; that is, this embodiment does not limit the setting of the preset specimen specifications. Optionally, the preset specimen specifications can be set based on human experience. For example, the preset specimen specifications can be set to the aforementioned φ50mm×100mm specifications. Alternatively, the preset specimen specifications can be dynamically adjusted according to actual application requirements. This embodiment does not limit this.

[0045] As an example, sample collection can begin: Samples can be collected in the study area using coal core drilling or block sampling methods. The diameter of the coal core should preferably be greater than 70 mm, and the block size should preferably be greater than 250 mm × 250 mm × 250 mm. Other sample sizes can be collected if other research needs arise. Simultaneously, the collected samples should be perpendicular to the bedding plane in their height direction and should not have obvious cracks. Then, specimen preparation is performed based on the sampled samples: the collected samples are processed into cylindrical specimens. For ease of comparison, a φ50 mm × 100 mm size is preferred. Other specimen sizes can be processed if other requirements exist; the specimen shape is not limited.

[0046] Step 1012: Perform a first CT scan on the coal and rock specimen in an unloaded state to obtain a first scan image.

[0047] The first CT scan of the coal and rock specimen is performed in an unloaded state. That is, after obtaining the coal and rock specimen, the first CT scan is performed on the coal and rock specimen without applying any load. In other words, after obtaining the coal and rock specimen, the first CT scan is performed directly on the obtained coal and rock specimen.

[0048] Optionally, the first scan image obtained by performing a first CT scan on the coal and rock specimen in an unloaded state can be used as a reference for the loaded state of the coal and rock specimen.

[0049] As an example, the first CT scan can be performed after the specimen preparation is completed: the prepared coal and rock specimen is placed flat on the CT scanning equipment for a no-load scan (first CT scan) to obtain the first scan image.

[0050] Step 1013: Apply a continuous load to the coal and rock specimen, and perform a second CT scan on the coal and rock specimen while it is under continuous load to obtain multiple second scan images.

[0051] The scanning parameters for the second CT scan are the same as those for the first CT scan.

[0052] Among them, the multiple second scan images obtained are scan images of coal and rock specimens under continuous load conditions.

[0053] Optionally, the lowest load in the continuous load can be applied to the coal and rock specimen first, and a second CT scan can be performed on the coal and rock specimen under the lowest load state to obtain a second scan image. Then, the load can be increased sequentially and a second CT scan can be performed to obtain at least one second scan image. Thus, after the above continuous load is applied to the coal and rock specimen and the second CT scan is performed, multiple second scan images of the coal and rock specimen under the above continuous load state can be obtained.

[0054] As an example, after the first CT scan, a load can be applied: a first-stage uniaxial or triaxial load (load state 1) can be applied to the prepared coal and rock specimen and held. The load application device can be a universal testing machine or other self-made equipment. The load application stage is selected according to the research purpose, and it is recommended to be no less than 30% of the uniaxial compressive strength (UCS) of the coal and rock specimen. Then, a second CT scan is performed: the coal and rock specimen under load is subjected to a second CT scan to obtain the second scan image of load state 1. The scanning parameters of the second CT scan must be consistent with the scanning parameters of the first CT scan. Thus, by repeating the application of load and the second CT scan, second scan images of all required load states can be obtained.

[0055] Furthermore, in some embodiments, coal and rock specimens and their first scanned images in an unloaded state, as well as multiple second scanned images of the coal and rock specimens under continuous load, can be obtained through various other public, legal, and compliant means. For example, the coal and rock specimens and their first scanned images in an unloaded state, as well as multiple second scanned images of the coal and rock specimens under continuous load, can be obtained from other devices that store these images via network transmission or physical copying. This embodiment does not impose any limitations on these methods.

[0056] In some embodiments, after acquiring a first scan image of the coal and rock specimen under unloaded conditions and multiple second scan images of the coal and rock specimen under continuous load conditions, the first scan image and multiple second scan images can be imported into three-dimensional reconstruction software for three-dimensional reconstruction, and noise in the first scan image and multiple second scan images can be eliminated by fast Fourier filtering and / or Gaussian filtering to enhance image quality.

[0057] Step 102: For any second scan image, determine the precise displacement of each voxel in the second scan image based on the second scan image and the first scan image.

[0058] In this context, the precise displacement of each voxel in the second scan image can be understood as the precise displacement of the corresponding point of the coal and rock specimen under the load state corresponding to the second scan image.

[0059] It should be noted that the precise displacement of each voxel in any second scan image includes multiple precise displacements in multiple directions, such as the x-axis direction, y-axis direction, and z-axis direction.

[0060] One possible implementation is to first segment both the second and first scan images into image subsets of equal size for any given second scan image. Based on these subsets, a coarse displacement of each voxel in the second scan image can be determined. Then, using this coarse displacement as boundary conditions, the precise displacement of each voxel in the second scan image can be determined using the Finite Element Method (FEM) based on both the second and first scan images. Since the precise displacement of each voxel in the second scan image can be determined using the coarse displacement determined from the image subsets as boundary conditions, the computational cost of the finite element method is effectively reduced, thus improving computational efficiency.

[0061] Step 103: Based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image in the first scan image, determine the strain of the corresponding point of the coal and rock specimen under the load state corresponding to the second scan image.

[0062] Since the precise displacement of each voxel in the second scan image can be understood as the precise displacement of the corresponding point of the coal and rock specimen under the load state corresponding to the second scan image, in some embodiments, the strain of each voxel in the second scan image can be determined based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image in the first scan image. This strain is the strain of the corresponding point of the coal and rock specimen under the load state corresponding to the second scan image.

[0063] In this invention, the strain can be determined based on precise displacement and position under unloaded conditions, thus effectively ensuring the accuracy and reliability of strain determination.

[0064] The method for determining the strain of a loaded coal and rock specimen provided in this embodiment acquires a coal and rock specimen and a first scan image of the specimen in an unloaded state, as well as multiple second scan images of the specimen under continuous load. For any given second scan image, based on the second scan image and the first scan image, the precise displacement of each voxel in the second scan image is determined. Then, based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image within the first scan image, the strain of the corresponding point on the coal and rock specimen under the load state corresponding to the second scan image is determined. Therefore, by combining CT and DVC technologies, the strain of any point on a loaded coal and rock specimen under a corresponding load state can be determined, effectively improving the accuracy and reliability of strain determination.

[0065] To clearly illustrate how the coarse and precise displacements of each voxel in the second scan image are determined in this invention, this embodiment provides another method for determining the strain of a loaded coal and rock specimen. Figure 2This is a flowchart illustrating another method for determining the strain of a loaded coal and rock specimen provided in an embodiment of the present invention.

[0066] like Figure 2 As shown, the method for determining the strain of the loaded coal and rock specimen includes the following steps:

[0067] Step 201: Obtain the coal and rock specimen and a first scan image of the coal and rock specimen under unloaded condition, as well as multiple second scan images of the coal and rock specimen under continuous load condition.

[0068] It should be noted that the execution process of this step can be referred to step 101 in the previous embodiment, as the principle is the same, and will not be repeated here.

[0069] Step 202: For any second scan image, the second scan image and the first scan image are divided into image subsets of the same size to determine the coarse displacement of each voxel in the second scan image based on the image subsets.

[0070] The image subset includes the first image subset corresponding to the first scanned image and the second image subset corresponding to the second scanned image.

[0071] Alternatively, the coarse displacement of each voxel in the second scan image can be determined based on a subset of the images through the following steps:

[0072] Step 2021: For any second scan image, divide the second scan image and the first scan image into image subsets of the same size to obtain multiple second image subsets and multiple first image subsets.

[0073] The second image subset is a subset of images obtained by segmenting the second scanned image, and the first image subset is a subset of images obtained by segmenting the first scanned image. The second image subset and the first image subset are the same size.

[0074] Optionally, the size of the second image subset and the first image subset is selected according to the size of the corresponding scanned image. For example, it can be 1 / 10 or 1 / 20 of the size of the corresponding scanned image in each of the x, y, and z axes, etc. This embodiment does not limit this.

[0075] Step 2022: For any first image subset, determine the position coordinate expression of any voxel in the corresponding second image subset as follows:

[0076]

[0077] Where u1(x1,y1,z1), v1(x1,y1,z1), and w1(x1,y1,z1) are the first displacement functions, representing the approximate displacement of any voxel (x1,y1,z1) in the first image subset under the load state corresponding to the second scan image in the x-axis, y-axis, and z-axis directions, respectively. * ,y1 * ,z1 * ) represents the position coordinates of any voxel (x1, y1, z1) in the second image subset corresponding to the first image subset.

[0078] Step 2023: Based on the first displacement function, the grayscale distribution function of the first image subset, and the grayscale distribution function of the second image subset corresponding to the first image subset, determine the first correlation function between the first image subset and the second image subset corresponding to the first image subset as follows:

[0079]

[0080] Where C1 represents the first correlation coefficient between the first image subset and the corresponding second image subset, S1 represents all first image subsets, Sp1 represents any voxel in the first image subset, f1(x1,y1,z1) represents the gray-level distribution function of the first image subset, and g1(x1,y1,z1) represents the gray-level distribution function of the first image subset. * ,y1 * ,z1 * ) represents the gray-level distribution function of the second image subset corresponding to the first image subset.

[0081] Step 2024: Based on the theory of continuum mechanics, the Taylor series expansion of the first displacement function is determined as follows:

[0082]

[0083] Where (u0, v0, w0) represents the approximate displacement of the central voxel in the first image subset in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image. The first derivative of the coarse displacement of the central voxel;

[0084] Step 2025, determine the first objective function as follows: The reverse combination Gauss-Newton algorithm is used to solve the first objective function based on the Taylor series expansion of the first displacement function and the first correlation function, so as to obtain the coarse displacement of any voxel in the first image subset under the load state corresponding to the second scan image in the x-axis, y-axis and z-axis directions.

[0085] Step 2026: Based on the coarse displacement of any voxel in each of the first image subsets in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image, determine the coarse displacement of each voxel in the second scan image.

[0086] It should be noted that the coarse displacement of each voxel in the determined second scan image includes multiple coarse displacements in multiple directions, such as the x-axis direction, y-axis direction, and z-axis direction.

[0087] Step 203: Using the coarse displacement of each voxel in the second scan image as the boundary condition, and based on the second scan image and the first scan image, the precise displacement of each voxel in the second scan image is determined by the finite element method (FEM).

[0088] Alternatively, the precise displacement of each voxel in the second scan image can be determined using the finite element method (FEM) with coarse displacement as the boundary condition through the following steps:

[0089] Step 2031: Based on a preset mesh size, divide the first scan image and the second scan image into a finite element mesh to obtain multiple first finite element elements corresponding to the first scan image and multiple second finite element elements corresponding to the second scan image.

[0090] Optionally, the preset grid size can be selected based on the size of the corresponding scanned image and the computing power of the computer; however, this embodiment does not impose any restrictions on this.

[0091] It should be noted that the preset mesh size should not be less than 15 voxels, because a mesh that is too small will affect the matching of elements, thus causing the calculation to fail to converge.

[0092] Step 2032, for any first finite element element, determine the position coordinate expression of any voxel in the corresponding second finite element element as follows:

[0093]

[0094] Where u2(x2,y2,z2), v2(x2,y2,z2), and w2(x2,y2,z2) are the second displacement functions, representing the precise displacements of any voxel (x2,y2,z2) in the first finite element element under the load state corresponding to the second scan image in the x-axis, y-axis, and z-axis directions, respectively. * ,y2 * z2 * ) represents the position coordinates of any voxel (x2, y2, z2) in the second finite element element corresponding to the first finite element element.

[0095] Step 2033: Based on the second displacement function, the grayscale distribution function of the first finite element element, and the grayscale distribution function of the second finite element element corresponding to the first finite element element, determine the second correlation function between the first finite element element and the second finite element element corresponding to the first finite element element as follows:

[0096]

[0097] Where C2 represents the second correlation function between the first finite element and the corresponding second finite element, e represents a finite element, S2 represents all the first finite element elements, Sp2 represents any voxel in e, f2(x2,y2,z2) represents the gray-scale distribution function of the first finite element, and g2(x2... * ,y2 * z2 * ) represents the grayscale distribution function of the second finite element corresponding to the first finite element.

[0098] Step 2034, based on finite element theory, determine the expression for the second displacement function as follows:

[0099]

[0100] Where n represents the number of voxels in the first finite element, N i (x2, y2, z2) are the shape functions of the first finite element, u i v i w i This represents the precise displacement of the i-th voxel in the first finite element element under the load state corresponding to the second scan image in the x-axis, y-axis, and z-axis directions.

[0101] Step 2035, determine the second objective function as follows: Using the Newton-Raphson iteration method, with the coarse displacement of each voxel in the second scan image as the boundary condition, the second objective function is solved according to the expression of the second displacement function and the second correlation function, so as to obtain the precise displacement of any voxel in the first finite element under the load state corresponding to the second scan image in the x-axis, y-axis and z-axis directions.

[0102] Since the second objective function can be solved using the coarse displacement of each voxel in the second scan image determined by the above steps as the boundary condition, the amount of computation is effectively reduced, which is beneficial to improving computational efficiency.

[0103] Step 2036: Determine the precise displacement of each voxel in the second scan image based on the precise displacement of any voxel in each of the first finite element units in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image.

[0104] It should be noted that the precise displacement of each voxel in the determined second scan image includes multiple precise displacements in multiple directions, such as the x-axis direction, y-axis direction, and z-axis direction.

[0105] Step 204: Determine the strain of each voxel in the second scan image based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image in the first scan image.

[0106] It should be noted that the other execution processes in this step can be referred to step 103 in the previous embodiment, and the principle is the same, so they will not be repeated here.

[0107] The method for determining the strain of loaded coal and rock specimens provided in this embodiment involves dividing any second scan image and the first scan image into image subsets of equal size. Based on these image subsets, a coarse displacement of each voxel in the second scan image is determined. Using this coarse displacement as boundary conditions, and based on the second and first scan images, the precise displacement of each voxel in the second scan image is determined using the finite element method (FEM). Finally, based on the precise displacement of each voxel in the second scan image and its position in the first scan image, the strain of each voxel in the second scan image is determined. Because the coarse displacement of each voxel in the second scan image is determined first during the process of determining the precise displacement, the precise displacement can be determined using the determined coarse displacement as boundary conditions during the process of determining the precise displacement of each voxel in the second scan image using the finite element method (FEM). This significantly reduces the computational load and effectively improves computational efficiency.

[0108] To clearly illustrate the above embodiments, examples are given below.

[0109] Figure 3 This is a flowchart illustrating a method for determining the strain of a loaded coal and rock specimen under a specific scenario, as provided in an embodiment of the present invention.

[0110] like Figure 3 As shown, the method for determining the strain of the loaded coal and rock specimen includes the following steps:

[0111] 1. Sample Collection: Samples shall be collected from the study area using coal core drilling or specimen sampling methods. The diameter of the coal core should preferably be greater than 70 mm, and the specimen size should preferably be greater than 250 mm × 250 mm × 250 mm. Other sample sizes may be collected if other research needs arise. The collected samples should be perpendicular to the bedding plane in their height direction and should not have obvious cracks.

[0112] 2. Preparation of coal and rock specimens: The collected samples are processed into cylindrical coal and rock specimens. For ease of comparison, it is advisable to use φ50mm×100mm. If there are other requirements, other specifications of specimens can also be processed. The shape of the specimens is not limited.

[0113] 3. Perform the first CT scan: Place the prepared coal and rock specimen flat on the CT scanning equipment for a no-load scan to obtain the initial state scan image (first scan image), which serves as a reference for the loaded state.

[0114] 4. Apply load: Apply a first-stage uniaxial or triaxial load to the prepared coal and rock specimens and maintain it. The load application device can be a universal testing machine or other self-made equipment. The load application stage is selected according to the research purpose, and it is recommended to apply a load not less than 30% of the uniaxial compressive strength (UCS) of the coal and rock specimen.

[0115] 5. Perform a second CT scan: Perform a CT scan on the coal and rock specimen under load to obtain a scan image of load state 1 (a second scan image). The CT scan parameters must be consistent with the parameters of the first CT scan.

[0116] 6. Repeat steps 4 to 5 until you obtain scan images of all the required load states (multiple second scan images).

[0117] 7. Image Enhancement: Import the images obtained in the above steps into 3D reconstruction software for 3D reconstruction, and use Fast Fourier Filtering and Gaussian Filtering algorithms to eliminate image noise and enhance image quality.

[0118] 8. Coarse displacement calculation based on image subsets:

[0119] 8.1 Divide the three-dimensional scanning images of the enhanced coal and rock specimen in the initial state and under load state 1 into image subsets of the same size. The size of the image subset is selected according to the size of the three-dimensional scanning image. The size of the image subset in each direction of the x, y, and z axes should be 1 / 10 of the size of the three-dimensional scanning image in that direction.

[0120] 8.2 Let the gray-level distribution function of any first image subset in the initial state three-dimensional scan image be expressed as f1(x1,y1,z1), and the gray-level distribution function of the second image subset corresponding to the aforementioned first image subset in the three-dimensional scan image of load state 1 be g1(x1,y1,z1). * ,y1 * ,z1 * The coordinates of each point before and after deformation are:

[0121]

[0122] In the formula, u1(x1,y1,z1), v1(x1,y1,z1), and w1(x1,y1,z1) are the approximate displacements of any point (x,y,z) on the coal and rock specimen in the x-axis, y-axis, and z-axis directions under load state 1; (x1 * ,y1 * ,z1 * ) represents the coordinates of the corresponding point after deformation.

[0123] Based on the Taylor series expansion of the displacement function in continuum mechanics:

[0124]

[0125] In the formula, (u0, v0, w0) represents the displacement of the center point of the first image subset in the coordinate direction under load state 1. Let C1 be the first derivative of the displacement at the center point. The correlation C1 between the subsets before and after deformation is represented by the correlation function:

[0126]

[0127] In the formula, S1 represents all the first image subsets, and Sp1 represents any point within the first image subset.

[0128] 8.3 Based on the principle of minimizing the correlation coefficient C1, the inverse compositional Gauss-Newton algorithm is used to solve equation (4) to obtain the displacement of any first image subset.

[0129]

[0130] 8.4 Repeat steps 8.1 to 8.3, traversing each first image subset to obtain the coarse displacement of the coal and rock specimen from the initial state to the load state 1 based on the image subset.

[0131] 9. Repeat step 8 to obtain the coarse displacement from the initial state to all load states, thereby obtaining the coarse displacement field inside the loaded coal and rock specimen based on a subset of images.

[0132] 10. Precise displacement calculation based on the finite element method (FEM):

[0133] 10.1 Finite element meshes were generated on the three-dimensional scan images of the enhanced coal and rock specimen in its initial state and under load state 1. The mesh size was selected based on the scan image size and computer computing power, and should not be less than 15 voxels. A mesh that is too small will affect node matching, thus causing the calculation to fail to converge.

[0134] 10.2 Considering the correlation of all elements, the correlation function C2 of the divided finite element is:

[0135]

[0136] In the formula, e represents a single element, S2 represents all the first finite element elements (obtained by dividing the finite element mesh on the initial three-dimensional scan image), and Sp2 represents any point within the element.

[0137] According to the finite element theory, the displacement of any point within an element can be expressed as a function of nodal displacements:

[0138]

[0139] In the formula, n is the number of nodes in the unit containing any point, and N i (x2, y2, z2) are the shape functions of the element, u i v i w i This represents the precise displacement of the i-th node in the coordinate direction under load state 1.

[0140] 10.3 Using the subset-based coarse displacement obtained in step 8 as the boundary condition, the Newton-Raphson iterative algorithm is used to solve equation (7) to obtain the optimal solution of all nodal displacements when C2 is minimized.

[0141]

[0142] The global displacement vector p = (u1, v1, w1, ..., u) is obtained. i ,v i ,w i ,…,u m ,v m ,w m ) T , where m is the total number of nodes. This allows us to obtain the precise displacement from the initial state to load state 1 based on the finite element method (FEM).

[0143] 11. Repeat step 10 to obtain the precise displacement from the initial state to all load states, thereby obtaining the precise displacement field inside the loaded coal and rock specimen based on the finite element method (FEM).

[0144] 12. Based on the precise displacement and initial state scan images from the initial state to all load states, the strain of the coal and rock specimens from the initial state to all load states is obtained.

[0145] In summary, this invention provides a method for determining the strain of a loaded coal and rock specimen. It can combine CT technology and DVC technology to determine the strain at any point of the loaded coal and rock specimen under the corresponding load state, effectively improving the accuracy and reliability of strain determination.

[0146] To achieve the above embodiments, the present invention also proposes a device for determining the strain of loaded coal and rock specimens.

[0147] Figure 4 This is a schematic diagram of a device for determining the strain of a loaded coal and rock specimen, provided in an embodiment of the present invention.

[0148] like Figure 4 As shown, the device for determining the strain of the loaded coal and rock specimen includes: an acquisition module 41, a first determination module 42, and a second determination module 43.

[0149] The acquisition module 41 is used to acquire the coal and rock specimen and a first scan image of the coal and rock specimen in an unloaded state, as well as multiple second scan images of the coal and rock specimen in a continuous load state.

[0150] The first determining module 42 is used to determine the precise displacement of each voxel in the second scan image based on the second scan image and the first scan image for any second scan image;

[0151] The second determining module 43 is used to determine the strain of the corresponding point of the coal and rock specimen under the load state corresponding to the second scan image based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image in the first scan image.

[0152] Furthermore, in one possible implementation of this invention, the first determining module 42 includes:

[0153] A first processing unit is configured to, for any second scan image, divide the second scan image and the first scan image into image subsets of the same size, so as to determine the coarse displacement of each voxel in the second scan image based on the image subsets;

[0154] The second processing unit is used to determine the precise displacement of each voxel in the second scan image based on the second scan image and the first scan image, using the coarse displacement of each voxel in the second scan image as a boundary condition and employing the finite element method (FEM).

[0155] Further, in one possible implementation of this invention, the image subset includes a first image subset corresponding to the first scanned image and a second image subset corresponding to the second scanned image; the first processing unit is specifically used for:

[0156] For any second scanned image, the second scanned image and the first scanned image are divided into image subsets of the same size to obtain multiple second image subsets and multiple first image subsets;

[0157] For any of the first image subsets, the expression for determining the position coordinates of any voxel in the corresponding second image subset is as follows:

[0158]

[0159] Where u1(x1,y1,z1), v1(x1,y1,z1), and w1(x1,y1,z1) are the first displacement functions, representing the approximate displacements of any voxel (x1,y1,z1) in the first image subset under the load state corresponding to the second scan image in the x-axis, y-axis, and z-axis directions, respectively. * ,y1 * ,z1 * ) represents the position coordinates of any voxel (x1, y1, z1) in the first image subset within the second image subset corresponding to the first image subset;

[0160] Based on the first displacement function, the grayscale distribution function of the first image subset, and the grayscale distribution function of the second image subset corresponding to the first image subset, the first correlation function between the first image subset and the second image subset corresponding to the first image subset is determined as follows:

[0161]

[0162] Where C1 represents the first correlation coefficient between the first image subset and the corresponding second image subset, S1 represents all the first image subsets, Sp1 represents any voxel in the first image subset, f1(x1,y1,z1) represents the gray-level distribution function of the first image subset, and g1(x1,y1,z1) represents the gray-level distribution function of the first image subset. * ,y1 * ,z1 * ) represents the grayscale distribution function of the second image subset corresponding to the first image subset;

[0163] According to the theory of continuum mechanics, the Taylor series expansion of the first displacement function is determined as follows:

[0164]

[0165] Wherein, (u0, v0, w0) represents the approximate displacement of the central voxel in the first image subset in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image. The first derivative of the coarse displacement of the central voxel;

[0166] The first objective function is determined as follows: The reverse combination Gauss-Newton algorithm is used to solve the first objective function based on the Taylor series expansion of the first displacement function and the first correlation function, so as to obtain the coarse displacement of any voxel of the first image subset in the x-axis, y-axis and z-axis directions under the load state corresponding to the second scan image.

[0167] Based on the coarse displacement of any voxel in each of the first image subsets in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image, the coarse displacement of each voxel in the second scan image is determined.

[0168] Furthermore, in one possible implementation of this invention, the second processing unit is specifically used for:

[0169] Based on a preset mesh size, a finite element mesh is divided on the first scanned image and the second scanned image to obtain multiple first finite element elements corresponding to the first scanned image and multiple second finite element elements corresponding to the second scanned image;

[0170] For any first finite element element, the position coordinate expression of any voxel in the corresponding second finite element element is determined as follows:

[0171]

[0172] Where u2(x2,y2,z2), v2(x2,y2,z2), and w2(x2,y2,z2) are the second displacement functions, representing the precise displacements of any voxel (x2,y2,z2) in the first finite element unit under the load state corresponding to the second scanned image in the x-axis, y-axis, and z-axis directions, respectively. * ,y2 * z2 * (x2, y2, z2) represents the position coordinates of any voxel (x2, y2, z2) in the first finite element element in the second finite element element corresponding to the first finite element element element;

[0173] Based on the second displacement function, the grayscale distribution function of the first finite element, and the grayscale distribution function of the second finite element corresponding to the first finite element, the second correlation function between the first finite element and the second finite element corresponding to the first finite element is determined as follows:

[0174]

[0175] Where C2 represents the second correlation function between the first finite element and the corresponding second finite element, e represents a finite element, S2 represents all the first finite element elements, Sp2 represents any voxel in e, f2(x2,y2,z2) represents the gray-scale distribution function of the first finite element, and g2(x2,y2,z2) represents the gray-scale distribution function of the first finite element. * ,y2 * z2 * ) represents the grayscale distribution function of the second finite element element corresponding to the first finite element element;

[0176] According to the finite element theory, the expression for the second displacement function is determined as follows:

[0177]

[0178] Where n represents the number of voxels in the first finite element unit, N i (x2, y2, z2) are the shape functions of the first finite element, u i v i w i This represents the precise displacement of the i-th voxel in the first finite element unit in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image;

[0179] The second objective function is determined as follows: Using the Newton iteration method, with the coarse displacement of each voxel in the second scanned image as the boundary condition, the second objective function is solved according to the expression of the second displacement function and the second correlation function, so as to obtain the precise displacement of any voxel in the first finite element in the x-axis, y-axis and z-axis directions under the load state corresponding to the second scanned image;

[0180] Based on the precise displacement of any voxel in the first finite element unit in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image, the precise displacement of each voxel in the second scan image is determined.

[0181] Furthermore, in one possible implementation of this invention, the acquisition module includes:

[0182] The third processing unit is used to obtain sampling samples in the area to be studied using a preset sampling method, and to process the sampling samples according to preset specimen specifications to obtain the coal and rock specimens.

[0183] A scanning unit is used to perform a first computed tomography (CT) scan on the coal and rock specimen in an unloaded state to obtain the first scan image;

[0184] The fourth processing unit is used to apply a continuous load to the coal and rock specimen and perform a second CT scan on the coal and rock specimen under the continuous load state to obtain the plurality of second scan images and the stress-strain curve, wherein the scanning parameters of the second CT scan are consistent with the scanning parameters of the first CT scan.

[0185] Furthermore, in one possible implementation of this invention, the third processing unit is specifically used for:

[0186] The sampling sample is obtained in the area to be studied by using a core drilling sampling method or a test block sampling method, wherein the diameter of the core drilling meets a preset threshold condition, and the specifications of the test block meet a preset specification condition.

[0187] Furthermore, in one possible implementation of the present invention, the above-described apparatus further includes:

[0188] The processing module is used to import the first scanned image and the plurality of second scanned images into 3D reconstruction software for 3D reconstruction, and to eliminate noise in the first scanned image and the plurality of second scanned images by fast Fourier filtering and / or Gaussian filtering.

[0189] It should be noted that the explanation of the aforementioned method for determining the strain of loaded coal and rock specimens also applies to the apparatus for determining the strain of loaded coal and rock specimens in this embodiment, and will not be repeated here.

[0190] The device for determining the strain of a loaded coal and rock specimen provided in this embodiment acquires a coal and rock specimen and a first scan image of the specimen in an unloaded state, as well as multiple second scan images of the specimen under continuous load. For any given second scan image, based on the second scan image and the first scan image, the precise displacement of each voxel in the second scan image is determined. Then, based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image within the first scan image, the strain of the corresponding point on the coal and rock specimen under the load state corresponding to the second scan image is determined. Therefore, by combining CT and DVC technologies, the strain of any point on the loaded coal and rock specimen under the corresponding load state can be determined, effectively improving the accuracy and reliability of strain determination.

[0191] To implement the above embodiments, the present invention also proposes an electronic device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to execute the method for determining the strain of loaded coal and rock specimens proposed in any of the above embodiments of the present invention.

[0192] To implement the above embodiments, the present invention also proposes a computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the method for determining the strain of a loaded coal and rock specimen proposed in any of the above embodiments of the present invention.

[0193] To implement the above embodiments, the present invention also proposes a computer program product, including a computer program that, when executed by a processor, implements the method for determining the strain of loaded coal and rock specimens proposed in any of the above embodiments of the present invention.

[0194] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0195] It should be noted that, Figure 5 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of the present invention.

[0196] like Figure 5 As shown, the electronic device includes:

[0197] The memory 51, the processor 52, and the computer program stored on the memory 51 and capable of running on the processor 52.

[0198] When processor 52 executes the program, it implements the method for determining the strain of loaded coal and rock specimens provided in any of the above embodiments.

[0199] Furthermore, electronic devices also include:

[0200] Communication interface 53 is used for communication between memory 51 and processor 52.

[0201] The memory 51 is used to store computer programs that can run on the processor 52.

[0202] The memory 51 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0203] The processor 52 is used to implement the method for determining the strain of loaded coal and rock specimens as described in any of the above embodiments when executing the program.

[0204] If the memory 51, processor 52, and communication interface 53 are implemented independently, then the communication interface 53, memory 51, and processor 52 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 5 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0205] Optionally, in a specific implementation, if the memory 51, processor 52, and communication interface 53 are integrated on a single chip, then the memory 51, processor 52, and communication interface 53 can communicate with each other through an internal interface.

[0206] Processor 52 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

[0207] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0208] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0209] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0210] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0211] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0212] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0213] Furthermore, the functional units in the various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0214] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for determining the strain of a loaded coal and rock specimen, characterized in that, include: Acquire a coal and rock specimen and a first scan image of the coal and rock specimen under an unloaded state, as well as multiple second scan images of the coal and rock specimen under a continuous load state; For any second scan image, determine the precise displacement of each voxel in the second scan image based on the second scan image and the first scan image; Based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image in the first scan image, the strain of the corresponding point of the coal and rock specimen under the load state corresponding to the second scan image is determined.

2. The method according to claim 1, characterized in that, For any given second scan image, determining the precise displacement of each voxel in the second scan image based on the second scan image and the first scan image includes: For any second scan image, the second scan image and the first scan image are divided into image subsets of the same size to determine the coarse displacement of each voxel in the second scan image based on the image subsets; Using the coarse displacement of each voxel in the second scan image as boundary conditions, the precise displacement of each voxel in the second scan image is determined by the finite element method (FEM) based on the second scan image and the first scan image.

3. The method according to claim 2, characterized in that, The image subset includes a first image subset corresponding to the first scanned image and a second image subset corresponding to the second scanned image; the step of dividing the second scanned image and the first scanned image into image subsets of the same size for any second scanned image, so as to determine the coarse displacement of each voxel in the second scanned image based on the image subsets, includes: For any second scanned image, the second scanned image and the first scanned image are divided into image subsets of the same size to obtain multiple second image subsets and multiple first image subsets; For any of the first image subsets, the expression for determining the position coordinates of any voxel in the corresponding second image subset is as follows: Where u1(x1,y1,z1), v1(x1,y1,z1), and w1(x1,y1,z1) are the first displacement functions, representing the approximate displacements of any voxel (x1,y1,z1) in the first image subset under the load state corresponding to the second scan image in the x-axis, y-axis, and z-axis directions, respectively. * ,y1 * ,z1 * ) represents the position coordinates of any voxel (x1, y1, z1) in the first image subset within the second image subset corresponding to the first image subset; Based on the first displacement function, the grayscale distribution function of the first image subset, and the grayscale distribution function of the second image subset corresponding to the first image subset, the first correlation function between the first image subset and the second image subset corresponding to the first image subset is determined as follows: Where C1 represents the first correlation coefficient between the first image subset and the corresponding second image subset, S1 represents all the first image subsets, Sp1 represents any voxel in the first image subset, f1(x1,y1,z1) represents the gray-level distribution function of the first image subset, and g1(x1,y1,z1) represents the gray-level distribution function of the first image subset. * ,y1 * ,z1 * ) represents the grayscale distribution function of the second image subset corresponding to the first image subset; According to the theory of continuum mechanics, the Taylor series expansion of the first displacement function is determined as follows: Wherein, (u0, v0, w0) represents the approximate displacement of the central voxel in the first image subset in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image. The first derivative of the coarse displacement of the central voxel; The first objective function is determined as follows: The reverse combination Gauss-Newton algorithm is used to solve the first objective function based on the Taylor series expansion of the first displacement function and the first correlation function, so as to obtain the coarse displacement of any voxel of the first image subset in the x-axis, y-axis and z-axis directions under the load state corresponding to the second scan image. Based on the coarse displacement of any voxel in each of the first image subsets in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image, the coarse displacement of each voxel in the second scan image is determined.

4. The method according to claim 2, characterized in that, The step of determining the precise displacement of each voxel in the second scanned image using the coarse displacement of each voxel in the second scanned image as a boundary condition, based on the second scanned image and the first scanned image, employs the finite element method (FEM), including: Based on a preset mesh size, a finite element mesh is divided on the first scanned image and the second scanned image to obtain multiple first finite element elements corresponding to the first scanned image and multiple second finite element elements corresponding to the second scanned image; For any first finite element element, the position coordinate expression of any voxel in the corresponding second finite element element is determined as follows: Where u2(x2,y2,z2), v2(x2,y2,z2), and w2(x2,y2,z2) are the second displacement functions, representing the precise displacements of any voxel (x2,y2,z2) in the first finite element unit under the load state corresponding to the second scanned image in the x-axis, y-axis, and z-axis directions, respectively. * ,y2 * z2 * (x2, y2, z2) represents the position coordinates of any voxel (x2, y2, z2) in the first finite element element in the second finite element element corresponding to the first finite element element element; Based on the second displacement function, the grayscale distribution function of the first finite element, and the grayscale distribution function of the second finite element corresponding to the first finite element, the second correlation function between the first finite element and the second finite element corresponding to the first finite element is determined as follows: Where C2 represents the second correlation function between the first finite element and the corresponding second finite element, e represents a finite element, S2 represents all the first finite element elements, Sp2 represents any voxel in e, f2(x2,y2,z2) represents the gray-scale distribution function of the first finite element, and g2(x2,y2,z2) represents the gray-scale distribution function of the first finite element. * ,y2 * z2 * ) represents the grayscale distribution function of the second finite element element corresponding to the first finite element element; According to the finite element theory, the expression for the second displacement function is determined as follows: Where n represents the number of voxels in the first finite element unit, N i (x2, y2, z2) are the shape functions of the first finite element, u i v i w i This represents the precise displacement of the i-th voxel in the first finite element unit in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image; The second objective function is determined as follows: Using the Newton iteration method, with the coarse displacement of each voxel in the second scanned image as the boundary condition, the second objective function is solved according to the expression of the second displacement function and the second correlation function, so as to obtain the precise displacement of any voxel in the first finite element in the x-axis, y-axis and z-axis directions under the load state corresponding to the second scanned image; Based on the precise displacement of any voxel in the first finite element unit in the x-axis, y-axis, and z-axis directions under the load state corresponding to the second scan image, the precise displacement of each voxel in the second scan image is determined.

5. The method according to claim 1, characterized in that, The acquisition of the coal and rock specimen and a first scan image of the coal and rock specimen in an unloaded state, as well as multiple second scan images of the coal and rock specimen under continuous load, includes: Samples are obtained in the area to be studied using a preset sampling method, and the samples are processed according to preset specimen specifications to obtain the coal and rock specimens. The coal and rock specimen was subjected to a first computed tomography (CT) scan in an unloaded state to obtain the first scan image; A continuous load is applied to the coal and rock specimen, and a second CT scan is performed on the coal and rock specimen under the continuous load state to obtain the plurality of second scan images, wherein the scanning parameters of the second CT scan are consistent with the scanning parameters of the first CT scan.

6. The method according to claim 5, characterized in that, The step of obtaining samples in the area to be studied using a preset sampling method includes: The sampling sample is obtained in the area to be studied by using a core drilling sampling method or a test block sampling method, wherein the diameter of the core drilling meets a preset threshold condition, and the specifications of the test block meet a preset specification condition.

7. The method according to any one of claims 1-6, characterized in that, After acquiring the first scan image of the coal and rock specimen under unloaded condition and multiple second scan images of the coal and rock specimen under continuous load condition, the method further includes: The first scanned image and the plurality of second scanned images are respectively imported into the 3D reconstruction software for 3D reconstruction, and noise in the first scanned image and the plurality of second scanned images is eliminated by fast Fourier filtering and / or Gaussian filtering.

8. A device for determining the strain of a loaded coal and rock specimen, characterized in that, include: The acquisition module is used to acquire a coal and rock specimen and a first scan image of the coal and rock specimen in an unloaded state, as well as multiple second scan images of the coal and rock specimen in a continuous load state; The first determining module is used to determine the precise displacement of each voxel in any second scan image based on the second scan image and the first scan image; The second determining module is used to determine the strain of the corresponding point of the coal and rock specimen under the load state corresponding to the second scan image based on the precise displacement of each voxel in the second scan image and the position of each voxel in the second scan image in the first scan image.

9. An electronic device, characterized in that, include: At least one processor; as well as A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-7.

10. A computer-readable storage medium storing computer instructions, characterized in that, The computer instructions are used to cause the computer to perform the method according to any one of claims 1-7.

Images