Stress transfer path identification method

Abstract

The invention relates to the technical field of computers, in particular to a stress transmission path identification method. The method comprises the steps that a surface image of a stope physical model is shot, a binary matrix corresponding to the surface image is determined, elements in the binary matrix correspond to pixel points in the surface image in a one-to-one mode, and values of the elements in the binary matrix are determined by gray values and gray threshold values of the pixel points in the surface image; determining a porosity distribution matrix corresponding to the surface image according to the binary matrix; and connecting adjacent minimum value points in the porosity distribution matrix to obtain a stress transfer path of the stope physical model. By the adoption of the scheme, the accuracy of stress transmission path recognition can be improved.

Description

Technical Field

[0001] The present disclosure relates to the field of computer technology, and in particular to a stress transfer path identification method. Background Art

[0002] In physical model tests, stress fields, especially vertical stress fields, are important components of test measurements. By measuring stress paths, the stability of the rock mass around the mine can be evaluated, especially the mechanisms of roof collapse, bottom bulging, spalling, and working face pressure can be explained from the perspective of stress evolution. Measuring the vertical stress transfer path can also help with rock support and pressure relief design. By analyzing the stress transfer path, stress concentration areas and weak points in the rock formation can be found, and effective pressure relief and support schemes can be designed to disperse pressure and strengthen weak points. At the same time, the vertical stress path can also verify the effectiveness of existing pressure relief and support schemes. However, it is difficult to accurately determine the stress transfer path of the model in existing mine physical model tests. Summary of the invention

[0003] The present disclosure aims to solve one of the technical problems in the related art at least to some extent.

[0004] To this end, a first objective of the present disclosure is to propose a stress transfer path identification method to improve the accuracy of stress transfer path identification.

[0005] A second objective of the present disclosure is to provide a stress transfer path identification device.

[0006] A third objective of the present disclosure is to provide an electronic device.

[0007] A fourth objective of the present disclosure is to provide a computer-readable storage medium.

[0008] A fifth object of the present disclosure is to provide a computer program product.

[0009] To achieve the above-mentioned purpose, a first embodiment of the present disclosure provides a stress transfer path identification method, comprising:

[0010] Taking a surface image of the physical model of the stope, and determining a binary matrix corresponding to the surface image, wherein the elements in the binary matrix correspond one-to-one to the pixels in the surface image, and the values ​​of the elements in the binary matrix are determined by the grayscale values ​​and grayscale thresholds of the pixels in the surface image;

[0011] Determining a porosity distribution matrix corresponding to the surface image according to the binary matrix;

[0012] Adjacent minimum points in the porosity distribution matrix are connected to obtain the stress transfer path of the stope physical model.

[0013] Optionally, determining a binary matrix corresponding to the surface image includes:

[0014] Converting the surface image into a grayscale image, and calculating the grayscale value of each pixel in the grayscale image;

[0015] The grayscale image is binarized to obtain a binary matrix corresponding to the surface image, wherein if the grayscale value is greater than the grayscale threshold, the element corresponding to the grayscale value is assigned a value of 1, and if the grayscale value is not greater than the grayscale threshold, the element corresponding to the grayscale value is assigned a value of 0.

[0016] Optionally, determining a porosity distribution matrix corresponding to the surface image according to the binary matrix includes:

[0017] Subtracting the binary matrix from the unit matrix to obtain a processed binary matrix;

[0018] Dividing the processed binary matrix into multiple sub-matrices, wherein the number of elements of the sub-matrices is determined by the minimum layer height of the stope physical model;

[0019] Determine the number of elements with a value of zero in each of the sub-matrices, determine the average porosity corresponding to each of the sub-matrices according to the number and the number of elements in the sub-matrices, and obtain an initial porosity distribution matrix, wherein the elements in the initial porosity distribution matrix correspond one-to-one to the sub-matrices, and the values ​​of the elements in the initial porosity distribution matrix are the average porosity;

[0020] The initial porosity distribution matrix is ​​subjected to nonlinear interpolation processing to obtain a porosity distribution matrix corresponding to the surface image, wherein the number of elements of the porosity distribution matrix is ​​the same as the number of elements of the processed binary matrix.

[0021] Optionally, performing nonlinear interpolation processing on the initial porosity distribution matrix includes:

[0022] Generate new elements between two adjacent elements in the same row of the initial porosity distribution matrix until the number of elements in the same row is the same as the number of columns of the processed binary matrix;

[0023] New elements are generated between two adjacent elements in the same column of the initial porosity distribution matrix until the number of elements in the same column is the same as the number of rows of the processed binary matrix.

[0024] Optionally, the method further comprises:

[0025] Determining the rock strata to be mined in the stope physical model;

[0026] According to the target mining strategy, mining is performed multiple times in the rock formation to be mined to obtain the goaf, and a first surface image before each mining and a second surface image after each mining are recorded, wherein the target mining strategy includes a mining direction and a mining length;

[0027] Stress distribution information corresponding to the goaf is determined according to a first binary matrix corresponding to the first surface image and a second binary matrix corresponding to the second surface image.

[0028] Optionally, determining the stress distribution information corresponding to the goaf according to a first binary matrix corresponding to the first surface image and a second binary matrix corresponding to the second surface image includes:

[0029] Subtracting a first binary matrix corresponding to the first surface image from a second binary matrix corresponding to the second surface image to obtain a new crack matrix, and performing skeleton extraction on the new crack matrix to obtain a new crack skeleton matrix;

[0030] Subtracting the first binary matrix and the second binary matrix from the unit matrix respectively to obtain a processed first binary matrix and a processed second binary matrix, and subtracting the processed first binary matrix from the processed second binary matrix to obtain a closed crack matrix, performing boundary extraction on the closed crack matrix to obtain a pre-closed crack boundary matrix;

[0031] The stress distribution information corresponding to the goaf is determined according to the new crack skeleton matrix and the pre-closure crack boundary matrix.

[0032] Optionally, determining the stress distribution information corresponding to the goaf according to the new crack skeleton matrix and the pre-closed crack boundary matrix includes:

[0033] Performing crack segmentation processing on the new crack skeleton matrix and the pre-closed crack boundary matrix respectively to obtain a segmented new crack skeleton matrix and a segmented pre-closed crack boundary matrix;

[0034] Performing connected domain identification on the segmented new crack skeleton matrix and the segmented pre-closed crack boundary matrix respectively, to obtain a first connected domain corresponding to the segmented new crack skeleton matrix and a second connected domain corresponding to the segmented pre-closed crack boundary matrix, wherein the first connected domain is the segmented new crack skeleton, and the second connected domain is the segmented crack boundary before closure;

[0035] A stress distribution matrix is ​​constructed according to the first connected domain, the second connected domain and the processed second binary matrix to obtain stress distribution information corresponding to the goaf.

[0036] Optionally, the performing crack segmentation processing on the newly formed crack skeleton matrix and the pre-closed crack boundary matrix respectively to obtain a segmented newly formed crack skeleton matrix and a segmented pre-closed crack boundary matrix comprises:

[0037] Determine the positions of the crack skeleton endpoints, intersections and crack inflection points in the new crack skeleton matrix and the pre-closed crack boundary matrix;

[0038] The elements at the locations of the crack skeleton endpoints, the intersections, and the crack inflection points, as well as eight elements around the locations, are all assigned values ​​of 0 to obtain a segmented new crack skeleton matrix and a segmented pre-closed crack boundary matrix.

[0039] Optionally, constructing a stress distribution matrix according to the first connected domain, the second connected domain and the processed second binary matrix includes:

[0040] Constructing an initial stress distribution matrix, wherein the matrix size of the initial stress distribution matrix is ​​the same as the newly formed crack skeleton matrix after segmentation and the pre-closed crack boundary matrix after segmentation;

[0041] The first element corresponding to the first connected domain in the initial stress distribution matrix and the second elements adjacent to the first element on both sides are assigned a value of 1,

[0042] If the third elements adjacent to the element corresponding to the second connected domain in the processed second binary matrix on both sides are greater than 0, assigning a value of 0 to the fourth element corresponding to the third element in the initial stress distribution matrix;

[0043] If the third element in the processed second binary matrix is ​​not greater than 0, assigning a value of -1 to the fourth element in the initial stress distribution matrix;

[0044] If the fifth element in the processed second binary matrix, except the elements corresponding to the first element and the second element, is greater than 0, assigning a value of 0 to the sixth element corresponding to the fifth element in the initial stress distribution matrix;

[0045] The unassigned elements in the initial stress distribution matrix except the first element, the second element, the fourth element, and the sixth element are assigned values ​​by interpolation to obtain a stress distribution matrix, wherein the areas in the stress distribution matrix where the element values ​​are less than 0 are areas subject to vertical compressive stress, the areas where the element values ​​are greater than 0 are areas subject to tensile stress, and the areas where the element values ​​are equal to 0 are stress-free areas.

[0046] Optionally, assigning values ​​to unassigned elements in the initial stress distribution matrix except the first element, the second element, the fourth element, and the sixth element by interpolation includes:

[0047] Assign values ​​of 0 to the unassigned elements in the first row of the initial stress distribution matrix except the first element, the second element, the fourth element, and the sixth element, and assign values ​​of -1 to the unassigned elements in the last row;

[0048] Nonlinear interpolation is performed on the unassigned elements in the initial stress distribution matrix except the unassigned elements in the first row and the unassigned elements in the last row.

[0049] To achieve the above-mentioned purpose, a second aspect of the present disclosure provides a stress transfer path identification device, comprising:

[0050] An image capturing unit, used for capturing a surface image of a physical model of a stope, and determining a binary matrix corresponding to the surface image, wherein elements in the binary matrix correspond one-to-one to pixels in the surface image, and values ​​of elements in the binary matrix are determined by grayscale values ​​and grayscale thresholds of pixels in the surface image;

[0051] A matrix determination unit, used to determine a porosity distribution matrix corresponding to the surface image according to the binary matrix;

[0052] The stress determination unit is used to connect adjacent minimum points in the porosity distribution matrix to obtain the stress transfer path of the stope physical model.

[0053] To achieve the above-mentioned purpose, a third aspect of the present disclosure provides an electronic device, including: a processor, and a memory communicatively connected to the processor;

[0054] Memory stores computer-executable instructions;

[0055] The processor executes the computer-executable instructions stored in the memory to implement the method shown in any one of the first aspects above.

[0056] To achieve the above-mentioned objectives, an embodiment of the fourth aspect of the present disclosure proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the method shown in any one of the above-mentioned first aspects.

[0057] To achieve the above-mentioned objective, a fifth aspect of the present disclosure provides a computer program product, including a computer program, which, when executed by a processor, implements the method shown in any one of the above-mentioned first aspects.

[0058] In summary, the method, device, equipment and storage medium provided by the present disclosure shoot the surface image of the physical model of the stope and determine the binary matrix corresponding to the surface image, wherein the elements in the binary matrix correspond to the pixels in the surface image one-to-one, and the values ​​of the elements in the binary matrix are determined by the grayscale value and grayscale threshold of the pixels in the surface image; according to the binary matrix, determine the porosity distribution matrix corresponding to the surface image; connect the adjacent minimum value points in the porosity distribution matrix to obtain the stress transfer path of the physical model of the stope. Therefore, the stress transfer path can be accurately identified based on the distribution of porosity.

[0059] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The above and / or additional aspects and advantages of the present disclosure will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0061] Figure 1 A schematic diagram of a flow chart of a stress transfer path identification method provided by an embodiment of the present disclosure;

[0062] Figure 2 A schematic diagram showing a stress transfer path provided by an embodiment of the present disclosure;

[0063] Figure 3 A stress distribution diagram of the bottom of a stope physical model provided by an embodiment of the present disclosure;

[0064] Figure 4 A schematic diagram of a flow chart of a method for determining stress distribution information provided by an embodiment of the present disclosure;

[0065] Figure 5 A schematic diagram of the structure of a stope physical model provided by an embodiment of the present disclosure;

[0066] Figure 6 A schematic diagram showing a grayscale image provided by an embodiment of the present disclosure;

[0067] Figure 7 A schematic diagram showing a characteristic matrix provided by an embodiment of the present disclosure;

[0068] Figure 8 A schematic diagram of the principle of crack inflection point identification provided by an embodiment of the present disclosure;

[0069] Fig. 9 A schematic structural diagram of a stress transfer path identification device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0070] Embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0071] It should be noted that currently a large number of geological engineering designs and early warnings are carried out through numerical simulations. However, since it is difficult to obtain field data in real time and accurately during the construction process, the numerical simulation results lack the support of effective field data, especially the verification of stress field distribution. The main reason is that in the process of overburden destruction and collapse, the contact and collision between rocks is a key link, which directly determines the morphology and stress distribution after the rock collapse. However, the current numerical simulation methods are difficult to accurately and efficiently predict and reproduce the collision and contact process between rocks during the collapse process. Therefore, it is necessary to predict or reproduce the deformation, destruction, and collapse process of the rock formation through physical model experiments, measure the stress field of the physical model, especially the transmission path of the vertical stress field, and compare it with the simulation results, so as to effectively verify the correctness of the numerical model.

[0072] In the stope similarity model experiment, the stress distribution in the physical model is mainly measured by photoelasticity, strain block and digital image correlation (DIC) techniques.

[0073] For photoelastic experiments, its main principle is a mechanical analysis method that uses optical methods to measure the stress state of each point on the model under loading. The model used in the experiment is made of transparent material with birefringence properties. According to the similarity ratio of the experiment, a model similar to the real object is made, and an external load similar to the actual load is applied to the model. In the polarized light field, some black and white or colored stripes can be observed on the loaded model, and these stripes can be used to determine the stress at each point of the model. The method of measuring the stress transfer path by burying strain blocks on models paved with sand and minerals mainly relies on the coordinated deformation of the model and strain to test the stress at the location of the strain block. However, the scope of use of photoelastic technology is mainly limited to models of transparent materials. It is not applicable to materials that are opaque or have low light transmittance. In addition, since the stress distribution of simple components under tension, compression, torsion and bending deformation is independent of the elastic modulus and Poisson's ratio of the material, this method is not applicable to experiments under complex loading or complex deformation.

[0074] For strain blocks, their composition includes substrates and strain gauges, where the mechanical properties of the substrate should be similar to those of the physical model, thereby ensuring that the substrate will not affect the stress distribution of the physical model and its coordinated deformation with the surrounding materials. The strain gauges in the strain blocks are mainly resistive strain gauges. The principle is that when a conductor or semiconductor material undergoes mechanical deformation under the action of external forces, its resistance value changes accordingly. However, the buried strain block method can only test local stress and it is difficult to analyze the overall strain field. In addition, since suitable substrates are usually difficult to find, rash use of this method may cause stress concentration in the measurement area.

[0075] As for DIC technology, it is done by spraying speckles on the surface of the model in advance, and then using the digital image correlation algorithm to calculate the movement of the speckles. The principle is to grid the images before and after deformation into different areas, assuming that each area is rigid motion. Then use the correlation function to find the mapping of the area before deformation in the image after deformation. There is a mapping relationship between the two areas with the largest correlation coefficient in the images before and after deformation. However, the accuracy of DIC is heavily dependent on the size and production level of the speckles, so there are problems with its reliability in experiments on different physical models. In addition, due to the principles of the correlation algorithm, the data measured by the DIC method is seriously distorted for large deformations of the model in a short period of time.

[0076] The present disclosure is described in detail below with reference to specific embodiments.

[0077] In the first embodiment, if Figure 1 As shown, Figure 1 The present invention provides a schematic flow chart of a stress transmission path identification method provided by an embodiment of the present invention. The method can be implemented by a computer program and can be run on a device for stress transmission path identification. The computer program can be integrated into an application or run as an independent tool application.

[0078] The stress transmission path identification device may be an electronic device having a stress transmission path identification function.

[0079] The stress transfer path identification method may be executed by an electronic device.

[0080] For example, the stress transfer path identification method includes the following steps:

[0081] S101, photographing a surface image of a physical model of a stope, and determining a binary matrix corresponding to the surface image;

[0082] According to some embodiments, the stope physical model refers to a physical model for conducting experiments that is constructed based on field data. The stope physical model can be constructed based on field data, for example.

[0083] In some embodiments, the similarity ratio of the stope physical model may be determined based on field data and laboratory experimental conditions, similar materials may be prepared based on the similarity ratio, and the stope physical model may be constructed using the similar materials.

[0084] The field data include but are not limited to the rock formation data obtained through field survey and drilling.

[0085] Among them, the materials that can be selected when constructing the physical model of the mining site include but are not limited to sand, plastic, gypsum powder, calcium carbonate, water, silicate cement, mica, etc.; among them, mica is mainly used to simulate the joints and interfaces of the physical model of the mining site.

[0086] According to some embodiments, the surface image of the stope physical model may be, for example, a color image taken by a SLR camera. In this case, the surface image needs to be converted into a grayscale image, and then the grayscale value of each pixel in the grayscale image is calculated; the grayscale image is binarized to obtain a binary matrix corresponding to the surface image. Therefore, the accuracy of obtaining the binary matrix can be improved.

[0087] In some embodiments, when calculating the grayscale value of each pixel in the grayscale image, the red, green, and blue values ​​of each pixel on the pixel matrix corresponding to the grayscale image can be analyzed, and then the grayscale value G of each pixel is determined by the following formula:

[0088] G=(red+green+blue) / 3

[0089] In some embodiments, the elements in the binary matrix correspond to the pixels in the surface image one by one, and the values ​​of the elements in the binary matrix are determined by the grayscale values ​​and grayscale thresholds of the pixels in the surface image. That is, when the grayscale image is subjected to image binarization, the grayscale threshold can be set, and the elements whose grayscale values ​​are greater than the grayscale threshold are assigned a value of 1, and the elements whose grayscale values ​​are not greater than the grayscale threshold are assigned a value of 0, thereby obtaining a binary image and a binary matrix Bm corresponding to the binary image.

[0090] The grayscale threshold does not specifically refer to a fixed threshold, and the grayscale threshold can be determined according to actual application scenarios, for example.

[0091] S102, determining a porosity distribution matrix corresponding to the surface image according to the binary matrix;

[0092] According to some embodiments, the porosity distribution matrix is ​​used to indicate the porosity distribution information of the surface of the stope physical model.

[0093] In some embodiments, the binary matrix Bm may be subtracted from the unit matrix I to obtain a processed binary matrix Bmr; the processed binary matrix Bmr may be equally divided into a plurality of sub-matrices Bmrn,m ; Determine the number N of elements with zero values ​​in each sub-matrix, and determine the average porosity corresponding to each sub-matrix based on the number N and the number of elements in the sub-matrix It is believed that the porosity of each element in the matrix is Then, according to the average porosity of each matrix The initial porosity distribution matrix phi is constructed. Therefore, the accuracy of constructing the initial porosity distribution matrix phi can be improved.

[0094] Among them, the sub-matrix Bmr n,m The number of elements in can be determined by the minimum layer height of the stope physical model. n,m The number of elements can be L×L, where L=8a, and a is the minimum layer height of the stope physical model.

[0095] Among them, the elements in the initial porosity distribution matrix correspond to the sub-matrices one by one, and the value of the element in the initial porosity distribution matrix is ​​the average porosity of the corresponding sub-matrix The average porosity For example, it can be N / L 2 .

[0096] It should be noted that since the matrix size of the initial porosity distribution matrix phi is X×Y, where X is [E / L], Y is [F / L], E is the number of rows of the processed binary matrix Bmr, F is the number of columns of the processed binary matrix Bmr, and [] represents the integer function, it is necessary to perform nonlinear interpolation processing on the initial porosity distribution matrix phi to obtain a porosity distribution matrix phir with the same number of elements as the processed binary matrix Bmr.

[0097] According to some embodiments, new elements may be generated between two adjacent elements in the same row of the initial porosity distribution matrix phi until the number of elements in the same row is the same as the number of columns of the processed binary matrix Bmr; new elements may be generated between two adjacent elements in the same column of the initial porosity distribution matrix phi until the number of elements in the same column is the same as the number of rows of the processed binary matrix Bmr, thereby obtaining the porosity distribution matrix phir.

[0098] In some embodiments, during the nonlinear interpolation process, the values ​​of the newly generated elements may be fitted by a polynomial through the values ​​of the existing elements, and then the values ​​of the newly generated elements between the existing elements may be solved by the polynomial.

[0099] The polynomial equation obtained by fitting can be expressed as z=D1x+D2y+D3x2+D4y2+…, where z is a newly generated element, and x and y are the row and column coordinates of the existing elements in the matrix, respectively.

[0100] It should be noted that by first interpolating the elements in the same row of the matrix and then interpolating the elements in the same column, the calculation speed can be accelerated and the efficiency of constructing the porosity distribution matrix phir can be improved.

[0101] Taking a scenario as an example, when L is 3, we can first perform cubic interpolation on the elements in the same row of the initial porosity distribution matrix phi, and generate new elements between the original elements, that is, in phi i，j and phi i，j+1 New elements are generated between them, so that the number of elements in the same row is the same as the number of columns of the processed binary matrix Bmr; similarly, cubic interpolation is performed on the elements in the same column of the initial porosity distribution matrix phi, and new elements are generated between the original elements, that is, in phi i，j and phi i+1，j Generate new elements between them so that the number of elements in the same column is the same as the number of rows of the processed binary matrix Bmr.

[0102] S103, connecting adjacent minimum points in the porosity distribution matrix to obtain a stress transfer path of the stope physical model.

[0103] According to some embodiments, if any element in the porosity distribution matrix is ​​smaller than its surrounding elements, the element is called a minimum point of the porosity distribution matrix.

[0104] Take a scenario as an example. Figure 2 A schematic diagram showing a stress transfer path provided by an embodiment of the present disclosure. Figure 2 As shown in the figure, the red dots represent the minimum points in the porosity distribution matrix. Connecting adjacent red dots, the lines obtained can be regarded as the stress transfer path of the mining field physical model.

[0105] In some embodiments, based on Figure 2 The stress distribution diagram at the bottom of the stope physical model can be obtained, such as Figure 3 As shown; then, the pressure distribution of the model was tested by laying pressure sensors at the bottom of the physical model of the stope, and then compared Figure 3 A comparison of the stress peak position shown and the stress peak position collected by the sensor shows that the two positions are similar, indicating that the method provided in this embodiment has a high accuracy in identifying the stress transfer path.

[0106] In some embodiments, after the stress transfer path of the stope physical model is obtained, the weak rock mass on the transfer path corresponding to the field data can be reinforced according to the stress transfer path.

[0107] In summary, the method provided in this embodiment identifies the stress transfer path through the distribution of porosity with a high recognition accuracy. In addition, the required equipment is simple and easy to operate. There is no need for special processing of the physical model of the mining site, no need for complex and expensive equipment, and the cost of measurement and analysis is low.

[0108] This embodiment also provides a method for determining stress distribution information, which can be executed by an electronic device.

[0109] For example, Figure 4 As shown, the stress distribution information determination method may include the following steps:

[0110] S201, determining the rock layer to be mined in the physical model of the stope;

[0111] Take a scenario as an example. Figure 5 This is a schematic diagram of the structure of a stope physical model provided by an embodiment of the present disclosure. Figure 4 As shown, the physical model of the stope includes multiple rock layers, among which the rock layers to be mined are the rock layers to be mined.

[0112] S202, performing multiple mining operations in the rock formation to be mined according to the target mining strategy to obtain a goaf area, and recording a first surface image before each mining operation and a second surface image after each mining operation;

[0113] According to some embodiments, Figure 5 As shown, the goaf refers to the blank area after mining in the physical model of the stope.

[0114] In some embodiments, the target production strategy includes the production direction (i.e. Figure 5 working face advancement direction) and mining length.

[0115] That is to say, the mining process of the stope physical model needs to always advance in the same rock layer in one direction, and the length of each mining is the same. In addition, it is necessary to take fixed-point photos of the stope physical model before and after each mining, so as to effectively record the morphology of the surface of the stope physical model before and after the cracks are generated.

[0116] S203, determining stress distribution information corresponding to the goaf according to a first binary matrix corresponding to the first surface image and a second binary matrix corresponding to the second surface image.

[0117] According to some embodiments, the process of constructing the first binary matrix and the second binary matrix may refer to the process of constructing the binary matrix in step S101, which will not be repeated here.

[0118] It should be noted that since there is a difference in the grayscale values ​​of the cracked area and the uncracked area in the grayscale image corresponding to the surface image, and the larger the crack opening, the greater the difference, the crack boundary can be identified by judging the image grayscale gradient. Secondly, since the crack opening is mainly affected by the tensile stress in the crack area, and the crack closure is mainly affected by the compressive stress, the tensile and compressive stress distribution information of the current goaf can be obtained by analyzing the surface images of the physical model of the mining field taken at two adjacent times. In addition, since the direction of crack opening and crack closure is consistent with the direction of force, the appearance and disappearance of cracks with different orientations can reflect the tensile and compressive stress characteristics in the vertical direction.

[0119] In some embodiments, in order to improve the quality of crack extraction, white matte paint can be sprayed on the surface of the stope physical model. Since the thickness of the matte paint cannot affect the normal collapse of the stope physical model, the thickness of the matte paint needs to meet the following conditions:

[0120]

[0121] Among them, ρ min is the minimum density among different rock layers, w is the width of the physical model of the stope, hmin is the minimum thickness of the rock layer, σ c It is the coating strength of matte paint.

[0122] In some embodiments, the surface area of ​​the stope physical model is greater than 2m 2 The distinguishable crack area should be larger than 1mm. 2 , in order to facilitate the subsequent image processing, 1mm 2 The crack needs 8 pixels to represent, so the camera needs to have more than 800w pixels.

[0123] According to some embodiments, the first binary matrix Bm-i corresponding to the first surface image and the second binary matrix Bm-i+1 corresponding to the second surface image can be subtracted to obtain a new crack matrix Bmn, and the skeleton of the new crack matrix Bmn is extracted to obtain a new crack skeleton matrix Bmnb; the first binary matrix Bm-i and the second binary matrix Bm-i+1 are respectively subtracted from the unit matrix I to obtain the processed first binary matrix Bmr-i and the processed second binary matrix Bmr-i+1, and the processed first binary matrix Bmr-i and the processed second binary matrix Bmr-i+1 are subtracted to obtain a closed crack matrix Bmc, and the boundary of the closed crack matrix Bmc is extracted to obtain a pre-closure crack boundary matrix Bmcb; according to the new crack skeleton matrix Bmnb and the pre-closure crack boundary matrix Bmcb, the stress distribution information corresponding to the goaf is determined.

[0124] In some embodiments, based on the Zhang-Suen algorithm, the skeleton of the new crack matrix Bmn can be extracted to obtain the new crack skeleton matrix Bmnb, which is the skeleton of the new cracks on the surface of the physical model of the stope.

[0125] In some embodiments, the boundaries before crack closure in the closed crack matrix Bmc may be extracted by using the Canny algorithm, and the matrix where the crack boundaries before closure are located is named the crack boundary matrix before closure Bmcb.

[0126] According to some embodiments, crack segmentation processing can be performed on the new crack skeleton matrix Bmnb and the pre-closure crack boundary matrix Bmcb respectively to obtain the segmented new crack skeleton matrix Bmnd and the segmented pre-closure crack boundary matrix Bmcd; connected domain identification is performed on the segmented new crack skeleton matrix Bmnd and the segmented pre-closure crack boundary matrix Bmcd respectively to obtain the first connected domain corresponding to the segmented new crack skeleton matrix Bmnd and the second connected domain Bmcd corresponding to the segmented pre-closure crack boundary matrix, wherein the first connected domain is the segmented new crack skeleton, and the second connected domain is the segmented crack boundary before closure; a stress distribution matrix is ​​constructed based on the first connected domain, the second connected domain and the processed second binary matrix Bmr-i+1 to obtain stress distribution information corresponding to the goaf.

[0127] In some embodiments, Figure 6 A schematic diagram showing a grayscale image provided by an embodiment of the present disclosure. Figure 6 As shown in the figure, the non-intersecting cracks on the surface of the physical model of the mining area are not all strictly straight lines, but can be regarded as the connection of multiple straight lines with different orientations. Therefore, when analyzing the stress direction of the cracks, it is necessary to segment the cracks at their inflection points according to the direction of the cracks after skeletonization, and then analyze the stress directions of different regions of the same crack.

[0128] In addition, during the image recognition process, the elements at the positions corresponding to the crack boundaries can be assigned a value of 1, and the elements at the remaining positions can be assigned a value of 0. The area surrounded by 1 is the cracked area. Among them, since the cracks after the skeleton is extracted intersect with each other, it is necessary to identify the intersections of the cracks and separate these intersecting cracks from the intersections. In addition, since the cracks are regarded as connected domains in the later process of crack processing, when segmenting cracks based on intersections, the intersections cannot only be assigned a value of 0, but all elements in the 3×3 pixel matrix where the intersections are located must be assigned a value of 0.

[0129] That is to say, when performing crack segmentation processing, the positions of the crack skeleton endpoints, intersections and crack inflection points in the new crack skeleton matrix Bmnb and the crack boundary matrix Bmcb before closure can be determined; the elements at the locations of the crack skeleton endpoints, intersections and crack inflection points and the eight elements around the positions are all assigned to 0 to obtain the segmented new crack skeleton matrix Bmnd and the segmented crack boundary matrix Bmcd before closure.

[0130] For example, the endpoints, intersection points and inflection points of the crack skeleton (xi, yj) and the eight elements around them can all be assigned the value of 0, that is, the elements at the positions (xi, yj), (xi-1, yj-1), (xi-1, yj), (xi-1, yj+1), (xi, yj-1), (xi, yj+1), (xi+1, yj-1), (xi+1, yj), and (xi+1, yj-1) are all assigned the value of 0.

[0131] In some embodiments, Figure 7 A schematic diagram showing a characteristic matrix provided by an embodiment of the present disclosure; wherein: Figure 7 (a) in is the endpoint feature matrix, Figure 7 (b) in is the intersection feature matrix. Figure 7 As shown, during the image recognition process, if Figure 7 The 3×3 pixel matrix shown in (a) in the figure can be regarded as the central element of the crack skeleton endpoint. Figure 7 For the 3×3 pixel matrix shown in (b), its central element can be regarded as a split intersection point.

[0132] In some embodiments, Figure 8 A schematic diagram of the principle of crack inflection point identification provided by an embodiment of the present disclosure. Figure 8 As shown in the figure, the cracks in the new crack skeleton matrix Bmnb and the crack boundary matrix Bmcb before closure can be identified and numbered based on the characteristics of the crack connected domain. The crack skeleton endpoints on each crack are identified respectively, and the two crack skeleton endpoints of a crack are named a and b respectively. When looking for the inflection point on the crack, the angle between any point c on the crack and the lines connecting a and b can be determined, that is, the angle θ between the straight line ca and the straight line cb. The position of point c corresponding to the extreme value of the angle θ is the crack inflection point.

[0133] According to some embodiments, an initial stress distribution matrix stress can be constructed, wherein the matrix size of the initial stress distribution matrix stress is the same as the segmented new crack skeleton matrix Bmnd and the segmented pre-closed crack boundary matrix Bmcd; and values ​​are assigned to elements in the initial stress distribution matrix stress according to the first connected domain, the second connected domain and the processed second binary matrix Bmr-i+1 to obtain a stress distribution matrix.

[0134] Among them, the location of the crack and the elements corresponding to both sides in the initial stress distribution matrix stress need to be assigned 1. In other words, the first element corresponding to the first connected domain in the initial stress distribution matrix stress and the second elements adjacent to both sides of the first element can be assigned 1.

[0135] Among them, since the second connected domain is the boundary before the crack is closed after segmentation, it is necessary to judge whether the elements in the processed second binary matrix Bmr-i+1 corresponding to the positions on both sides of the crack are greater than 0. If the third elements on both sides of the elements corresponding to the second connected domain in the processed second binary matrix Bm-i+1 are greater than 0, the fourth element corresponding to the third element in the initial stress distribution matrix stress is assigned to 0; if the third element in the processed second binary matrix Bmr-i+1 is not greater than 0, the fourth element in the initial stress distribution matrix stress is assigned to -1.

[0136] Among them, it is necessary to determine whether the positions other than the first connected domain and the positions on both sides of the first connected domain in the segmented new crack skeleton matrix Bmnd are greater than 0 in the processed second binary matrix Bm-i+1. If greater than 0, it means that the position is a crack, and the element corresponding to the position in the initial stress distribution matrix stress is assigned 0. In other words, if the fifth element in the processed second binary matrix Bm-i+1 except the first element and the elements corresponding to the second element is greater than 0, the sixth element corresponding to the fifth element in the initial stress distribution matrix stress can be assigned 0.

[0137] Among them, the unassigned elements except the first element, the second element, the fourth element and the sixth element in the initial stress distribution matrix stress can be assigned values ​​through interpolation.

[0138] In some embodiments, when unassigned elements are assigned values ​​through interpolation, the first row of unassigned elements in the initial stress distribution matrix except the first element, the second element, the fourth element, and the sixth element can be assigned to 0, and the last row of unassigned elements can be assigned to -1; nonlinear interpolation is performed on the unassigned elements in the initial stress distribution matrix except the first row of unassigned elements and the last row of unassigned elements.

[0139] In some embodiments, when nonlinear interpolation is performed on unassigned elements, the specific interpolation process may refer to the nonlinear interpolation process in step S102, which will not be repeated here.

[0140] In some embodiments, Figure 2 As shown, the tensile and compressive stresses around the crack can be annotated in the form of a thermal map, where the area with an element value less than 0 in the corresponding stress distribution matrix is ​​the area subject to vertical compressive stress, the area with an element value greater than 0 is the area subject to tensile stress, and the area with an element value equal to 0 is the stress-free area.

[0141] Among them, in the process of overburden accumulation under the action of gravity, the gaps between the collapsed rocks in the goaf will decrease with the increase of compressive stress between rocks, and the denser the rock accumulation, the more conducive to stress transfer.

[0142] In summary, the method provided in this embodiment can quickly mark the tensile and compressive stress areas on the surface of the physical model of the mining field with high accuracy through the generation and closure of cracks in the first surface image before each mining and the second surface image after mining.

[0143] In order to implement the above embodiments, the present disclosure also proposes a stress transfer path identification device.

[0144] like Fig. 9 As shown, the stress transfer path identification device 900 includes:

[0145] An image capturing unit 901 is used to capture a surface image of the physical model of the stope and determine a binary matrix corresponding to the surface image, wherein the elements in the binary matrix correspond to the pixels in the surface image one by one, and the values ​​of the elements in the binary matrix are determined by the grayscale values ​​and grayscale thresholds of the pixels in the surface image;

[0146] A matrix determination unit 902, used to determine a porosity distribution matrix corresponding to the surface image according to the binary matrix;

[0147] The stress determination unit 903 is used to connect adjacent minimum value points in the porosity distribution matrix to obtain the stress transfer path of the stope physical model.

[0148] Optionally, when the image capturing unit 901 is used to determine the binary matrix corresponding to the surface image, it is specifically used to:

[0149] Convert the surface image into a grayscale image and calculate the grayscale value of each pixel in the grayscale image;

[0150] The grayscale image is binarized to obtain a binary matrix corresponding to the surface image, in which if the grayscale value is greater than the grayscale threshold, the element corresponding to the grayscale value is assigned a value of 1, and if the grayscale value is not greater than the grayscale threshold, the element corresponding to the grayscale value is assigned a value of 0.

[0151] Optionally, when the matrix determination unit 902 is used to determine the porosity distribution matrix corresponding to the surface image according to the binary matrix, it is specifically used to:

[0152] Subtract the binary matrix from the unit matrix to obtain the processed binary matrix;

[0153] The processed binary matrix is ​​equally divided into a plurality of sub-matrices, wherein the number of elements of the sub-matrices is determined by the minimum layer height of the stope physical model;

[0154] Determine the number of elements with zero values ​​in each sub-matrix, determine the average porosity corresponding to each sub-matrix according to the number and the number of elements in the sub-matrix, and obtain an initial porosity distribution matrix, wherein the elements in the initial porosity distribution matrix correspond to the sub-matrices one-to-one, and the values ​​of the elements in the initial porosity distribution matrix are the average porosities;

[0155] The initial porosity distribution matrix is ​​subjected to nonlinear interpolation processing to obtain the porosity distribution matrix corresponding to the surface image, wherein the number of elements of the porosity distribution matrix is ​​the same as the number of elements of the processed binary matrix.

[0156] Optionally, when the matrix determination unit 902 is used to perform nonlinear interpolation processing on the initial porosity distribution matrix, it is specifically used to:

[0157] Generate new elements between two adjacent elements in the same row of the initial porosity distribution matrix until the number of elements in the same row is the same as the number of columns of the processed binary matrix;

[0158] New elements are generated between two adjacent elements in the same column of the initial porosity distribution matrix until the number of elements in the same column is the same as the number of rows of the processed binary matrix.

[0159] Optionally, the stress determination unit 903 is further configured to:

[0160] Determine the rock formation to be mined in the physical model of the stope;

[0161] According to the target mining strategy, multiple mining is carried out in the rock layer to be mined to obtain the goaf area, and the first surface image before each mining and the second surface image after the mining are recorded, wherein the target mining strategy includes the mining direction and the mining length;

[0162] Stress distribution information corresponding to the goaf is determined according to a first binary matrix corresponding to the first surface image and a second binary matrix corresponding to the second surface image.

[0163] Optionally, the stress determination unit 903 is used to determine the stress distribution information corresponding to the goaf according to the first binary matrix corresponding to the first surface image and the second binary matrix corresponding to the second surface image, specifically to:

[0164] Subtracting a first binary matrix corresponding to the first surface image from a second binary matrix corresponding to the second surface image to obtain a new crack matrix, and performing skeleton extraction on the new crack matrix to obtain a new crack skeleton matrix;

[0165] The first binary matrix and the second binary matrix are respectively subtracted from the unit matrix to obtain the processed first binary matrix and the processed second binary matrix, and the processed first binary matrix and the processed second binary matrix are subtracted to obtain a closed crack matrix, and the boundary of the closed crack matrix is ​​extracted to obtain a crack boundary matrix before closure;

[0166] According to the new crack skeleton matrix and the crack boundary matrix before closure, the stress distribution information corresponding to the goaf is determined.

[0167] Optionally, when the stress determination unit 903 is used to determine the stress distribution information corresponding to the goaf according to the new crack skeleton matrix and the crack boundary matrix before closure, it is specifically used to:

[0168] Perform crack segmentation processing on the new crack skeleton matrix and the crack boundary matrix before closure respectively, and obtain the segmented new crack skeleton matrix and the segmented crack boundary matrix before closure;

[0169] The connected domains of the segmented new crack skeleton matrix and the segmented pre-closed crack boundary matrix are identified respectively, and the first connected domain corresponding to the segmented new crack skeleton matrix and the second connected domain corresponding to the segmented pre-closed crack boundary matrix are obtained, wherein the first connected domain is the segmented new crack skeleton, and the second connected domain is the segmented crack boundary before closure;

[0170] A stress distribution matrix is ​​constructed according to the first connected domain, the second connected domain and the processed second binary matrix to obtain stress distribution information corresponding to the goaf.

[0171] Optionally, the stress determination unit 903 is used to perform crack segmentation processing on the new crack skeleton matrix and the pre-closed crack boundary matrix respectively, and obtain the segmented new crack skeleton matrix and the segmented pre-closed crack boundary matrix, specifically for:

[0172] Determine the locations of the crack skeleton endpoints, intersections, and crack inflection points in the new crack skeleton matrix and the crack boundary matrix before closure;

[0173] The elements at the crack skeleton endpoints, intersections, and crack inflection points, as well as the eight elements around the locations, are all assigned 0 to obtain the segmented new crack skeleton matrix and the segmented pre-closed crack boundary matrix.

[0174] Optionally, when the stress determination unit 903 is used to construct a stress distribution matrix according to the first connected domain, the second connected domain and the processed second binary matrix, it is specifically used to:

[0175] An initial stress distribution matrix is ​​constructed, wherein the matrix size of the initial stress distribution matrix is ​​the same as the matrix of the newly formed crack skeleton after segmentation and the matrix of the crack boundary before closure after segmentation;

[0176] The first element corresponding to the first connected domain in the initial stress distribution matrix and the second elements adjacent to the first element on both sides are assigned a value of 1.

[0177] If the third elements on both sides of the element corresponding to the second connected domain in the processed second binary matrix are greater than 0, the fourth element corresponding to the third element in the initial stress distribution matrix is ​​assigned a value of 0;

[0178] If the third element in the processed second binary matrix is ​​not greater than 0, the fourth element in the initial stress distribution matrix is ​​assigned a value of -1;

[0179] If the fifth element in the processed second binary matrix, except the first element and the element corresponding to the second element, is greater than 0, the sixth element corresponding to the fifth element in the initial stress distribution matrix is ​​assigned a value of 0;

[0180] The unassigned elements except the first element, the second element, the fourth element and the sixth element in the initial stress distribution matrix are assigned values ​​by interpolation to obtain a stress distribution matrix, wherein the area with an element value less than 0 in the stress distribution matrix is ​​the area subject to vertical compressive stress, the area with an element value greater than 0 is the area subject to tensile stress, and the area with an element value equal to 0 is the stress-free area.

[0181] Optionally, when the stress determination unit 903 is used to assign values ​​to unassigned elements except the first element, the second element, the fourth element, and the sixth element in the initial stress distribution matrix through interpolation, it is specifically used to:

[0182] In the initial stress distribution matrix, the first row of unassigned elements except the first element, the second element, the fourth element, and the sixth element are assigned to 0, and the last row of unassigned elements are assigned to -1;

[0183] Nonlinear interpolation is performed on the unassigned elements in the initial stress distribution matrix except for the unassigned elements in the first row and the unassigned elements in the last row.

[0184] It should be noted that the above explanations of the stress transmission path identification method embodiment are also applicable to the stress transmission path identification device of this embodiment, and will not be repeated here.

[0185] In summary, the device provided by the embodiment of the present disclosure shoots the surface image of the physical model of the stope and determines the binary matrix corresponding to the surface image, wherein the elements in the binary matrix correspond to the pixels in the surface image one-to-one, and the values ​​of the elements in the binary matrix are determined by the grayscale value and grayscale threshold of the pixels in the surface image; according to the binary matrix, the porosity distribution matrix corresponding to the surface image is determined; adjacent minimum value points in the porosity distribution matrix are connected to obtain the stress transfer path of the physical model of the stope. Therefore, the stress transfer path can be accurately identified based on the distribution of porosity.

[0186] In order to implement the above embodiments, the present disclosure also proposes an electronic device, including: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0187] In order to implement the above embodiments, the present disclosure further proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided by the above embodiments.

[0188] In order to implement the above embodiments, the present disclosure also proposes a computer program product, including a computer program, which implements the methods provided by the above embodiments when executed by a processor.

[0189] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this disclosure shall comply with the relevant laws and regulations and shall not violate public order and good morals.

[0190] It should be noted that personal information from users should be collected for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. In addition, such collection / sharing should be carried out after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign the agreement / authorization including authorization of relevant user information before the user uses the function. In addition, any necessary steps should be taken to protect and safeguard access to such personal information data and ensure that others who have access to personal information data comply with its privacy policy and procedures.

[0191] The present disclosure anticipates providing implementation schemes for users to selectively block the use or access of personal information data. That is, the present disclosure anticipates providing hardware and / or software to prevent or block access to such personal information data. Once the personal information data is no longer needed, risks can be minimized by limiting data collection and deleting the data. In addition, when applicable, such personal information is de-identified to protect the privacy of the user.

[0192] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0193] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0194] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present disclosure includes additional implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present disclosure belong.

[0195] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing in a suitable manner if necessary, and then stored in a computer memory.

[0196] It should be understood that the various parts of the present disclosure can be implemented in hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0197] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0198] In addition, each functional unit in each embodiment of the present disclosure may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0199] The storage medium mentioned above may be a read-only memory, a disk or an optical disk, etc. Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present disclosure. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present disclosure.

Claims

1. A stress transfer path identification method, characterized in that: include: Taking a surface image of the physical model of the stope, and determining a binary matrix corresponding to the surface image, wherein the elements in the binary matrix correspond one-to-one to the pixels in the surface image, and the values ​​of the elements in the binary matrix are determined by the grayscale values ​​and grayscale thresholds of the pixels in the surface image; Determining a porosity distribution matrix corresponding to the surface image according to the binary matrix; Adjacent minimum points in the porosity distribution matrix are connected to obtain the stress transfer path of the stope physical model.

2. The method according to claim 1, characterized in that The step of determining a binary matrix corresponding to the surface image comprises: Converting the surface image into a grayscale image, and calculating the grayscale value of each pixel in the grayscale image; The grayscale image is binarized to obtain a binary matrix corresponding to the surface image, wherein if the grayscale value is greater than the grayscale threshold, the element corresponding to the grayscale value is assigned a value of 1, and if the grayscale value is not greater than the grayscale threshold, the element corresponding to the grayscale value is assigned a value of 0.

3. The method according to claim 1, characterized in that Determining the porosity distribution matrix corresponding to the surface image according to the binary matrix includes: Subtracting the binary matrix from the unit matrix to obtain a processed binary matrix; Dividing the processed binary matrix into multiple sub-matrices, wherein the number of elements of the sub-matrices is determined by the minimum layer height of the stope physical model; Determine the number of elements with a value of zero in each of the sub-matrices, determine the average porosity corresponding to each of the sub-matrices according to the number and the number of elements in the sub-matrices, and obtain an initial porosity distribution matrix, wherein the elements in the initial porosity distribution matrix correspond one-to-one to the sub-matrices, and the values ​​of the elements in the initial porosity distribution matrix are the average porosity; The initial porosity distribution matrix is ​​subjected to nonlinear interpolation processing to obtain a porosity distribution matrix corresponding to the surface image, wherein the number of elements of the porosity distribution matrix is ​​the same as the number of elements of the processed binary matrix.

4. The method according to claim 3, characterized in that The performing nonlinear interpolation processing on the initial porosity distribution matrix comprises: Generate new elements between two adjacent elements in the same row of the initial porosity distribution matrix until the number of elements in the same row is the same as the number of columns of the processed binary matrix; New elements are generated between two adjacent elements in the same column of the initial porosity distribution matrix until the number of elements in the same column is the same as the number of rows of the processed binary matrix.

5. The method according to claim 1, characterized in that The method further comprises: Determining the rock strata to be mined in the stope physical model; According to the target mining strategy, mining is performed multiple times in the rock formation to be mined to obtain the goaf, and a first surface image before each mining and a second surface image after each mining are recorded, wherein the target mining strategy includes a mining direction and a mining length; Stress distribution information corresponding to the goaf is determined according to a first binary matrix corresponding to the first surface image and a second binary matrix corresponding to the second surface image.

6. The method according to claim 5, characterized in that Determining the stress distribution information corresponding to the goaf according to the first binary matrix corresponding to the first surface image and the second binary matrix corresponding to the second surface image includes: Subtracting a first binary matrix corresponding to the first surface image from a second binary matrix corresponding to the second surface image to obtain a new crack matrix, and performing skeleton extraction on the new crack matrix to obtain a new crack skeleton matrix; Subtracting the first binary matrix and the second binary matrix from the unit matrix respectively to obtain a processed first binary matrix and a processed second binary matrix, and subtracting the processed first binary matrix from the processed second binary matrix to obtain a closed crack matrix, performing boundary extraction on the closed crack matrix to obtain a pre-closed crack boundary matrix; The stress distribution information corresponding to the goaf is determined according to the new crack skeleton matrix and the pre-closure crack boundary matrix.

7. The method according to claim 6, characterized in that Determining the stress distribution information corresponding to the goaf according to the new crack skeleton matrix and the pre-closed crack boundary matrix includes: Performing crack segmentation processing on the new crack skeleton matrix and the pre-closed crack boundary matrix respectively to obtain a segmented new crack skeleton matrix and a segmented pre-closed crack boundary matrix; Performing connected domain identification on the segmented new crack skeleton matrix and the segmented pre-closed crack boundary matrix respectively, to obtain a first connected domain corresponding to the segmented new crack skeleton matrix and a second connected domain corresponding to the segmented pre-closed crack boundary matrix, wherein the first connected domain is the segmented new crack skeleton, and the second connected domain is the segmented crack boundary before closure; A stress distribution matrix is ​​constructed according to the first connected domain, the second connected domain and the processed second binary matrix to obtain stress distribution information corresponding to the goaf.

8. The method according to claim 7, characterized in that The crack segmentation process is performed on the new crack skeleton matrix and the pre-closed crack boundary matrix respectively to obtain the segmented new crack skeleton matrix and the segmented pre-closed crack boundary matrix, including: Determine the positions of the crack skeleton endpoints, intersections and crack inflection points in the new crack skeleton matrix and the pre-closed crack boundary matrix; The elements at the locations of the crack skeleton endpoints, the intersections, and the crack inflection points, as well as eight elements around the locations, are all assigned values ​​of 0 to obtain a segmented new crack skeleton matrix and a segmented pre-closed crack boundary matrix.

9. The method according to claim 7, characterized in that: The step of constructing a stress distribution matrix according to the first connected domain, the second connected domain and the processed second binary matrix includes: Constructing an initial stress distribution matrix, wherein the matrix size of the initial stress distribution matrix is ​​the same as the newly formed crack skeleton matrix after segmentation and the pre-closed crack boundary matrix after segmentation; The first element corresponding to the first connected domain in the initial stress distribution matrix and the second elements adjacent to the first element on both sides are assigned a value of 1, If the third elements adjacent to the element corresponding to the second connected domain in the processed second binary matrix on both sides are greater than 0, assigning a value of 0 to the fourth element corresponding to the third element in the initial stress distribution matrix; If the third element in the processed second binary matrix is ​​not greater than 0, assigning a value of -1 to the fourth element in the initial stress distribution matrix; If the fifth element in the processed second binary matrix, except the elements corresponding to the first element and the second element, is greater than 0, assigning a value of 0 to the sixth element corresponding to the fifth element in the initial stress distribution matrix; The unassigned elements in the initial stress distribution matrix except the first element, the second element, the fourth element, and the sixth element are assigned values ​​by interpolation to obtain a stress distribution matrix, wherein the areas in the stress distribution matrix where the element values ​​are less than 0 are areas subject to vertical compressive stress, the areas where the element values ​​are greater than 0 are areas subject to tensile stress, and the areas where the element values ​​are equal to 0 are stress-free areas.

10. The method according to claim 9, characterized in that The step of assigning values ​​to the unassigned elements in the initial stress distribution matrix except the first element, the second element, the fourth element, and the sixth element by interpolation includes: Assign values ​​of 0 to the unassigned elements in the first row of the initial stress distribution matrix except the first element, the second element, the fourth element, and the sixth element, and assign values ​​of -1 to the unassigned elements in the last row; Nonlinear interpolation is performed on the unassigned elements in the initial stress distribution matrix except the unassigned elements in the first row and the unassigned elements in the last row.

Images