Method, device, electronic device and storage medium for characterizing crack evolution

Abstract

The present application proposes a method, device, electronic device and storage medium for characterizing crack evolution, which relates to the technical field of rock mechanics research. The method includes: obtaining reference stress-strain curves and reference stress values ​​corresponding to multiple reference rocks; determining a first stress gradient corresponding to a first type of rock based on the reference stress-strain curve and the reference stress value; obtaining scanning data of a reference rock sample under the first stress gradient; extracting the skeleton structure corresponding to each crack in the scanning data; determining a first characteristic parameter value corresponding to the reference rock sample based on the skeleton structure; and generating description information of the crack evolution of the first type of rock based on the first characteristic parameter value. The crack evolution process inside the rock can be quantitatively characterized, making the description information more intuitive, and providing conditions for improving the accuracy of predicting the rock failure time and state at the time of failure.

Description

Technical Field

[0001] The present application relates to the technical field of rock mechanics research, and in particular to a method, device, electronic device and storage medium for characterizing fracture evolution. Background Art

[0002] In the context of social production and life, resource mining, and other scenarios, rock damage often leads to geological disasters, resource mining interruptions, and other problems, which seriously threaten life and property safety. Therefore, early judgment and prevention of rock damage is an important way to improve production safety and reduce economic losses.

[0003] However, there is currently a lack of more accurate and reliable indicators for quantifying the structure of internal cracks in rocks to characterize the evolution of internal cracks in coal and rock masses. Therefore, this application has determined a characterization method for crack evolution to improve the accuracy and reliability of damage prediction. Summary of the invention

[0004] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0005] To this end, the purpose of this application is to propose a characterization method, device, electronic device and storage medium for crack evolution, so as to quantify the degree of rock damage, so as to more intuitively and accurately describe the evolution and development process of cracks inside the rock, and provide conditions for improving the accuracy of rock damage prediction.

[0006] According to a first aspect of the present application, a method for characterizing crack evolution is provided, comprising:

[0007] Obtaining reference stress-strain curves and reference stress values ​​corresponding to a plurality of reference rock samples, wherein the plurality of reference rock samples are all first type rocks, and the reference stress value is a stress peak value of the reference stress-strain curve;

[0008] Determining a first stress gradient corresponding to the first type of rock based on the reference stress-strain curve and the reference stress value;

[0009] Acquire scanning data of the reference rock sample under the first stress gradient;

[0010] Extracting a skeleton structure corresponding to each crack in the scan data;

[0011] Determining a first characteristic parameter value corresponding to the reference rock sample according to the skeleton structure;

[0012] Based on the first characteristic parameter value, descriptive information of the fracture evolution of the first type of rock is generated.

[0013] According to a second aspect of the present application, a device for characterizing crack evolution is provided, comprising:

[0014] A first acquisition module is used to acquire reference stress-strain curves and reference stress values ​​corresponding to a plurality of reference rock samples, wherein the plurality of reference rock samples are all first type rocks, and the reference stress value is a stress peak value of the reference stress-strain curve;

[0015] A first determination module, configured to determine a first stress gradient corresponding to the first type of rock based on the reference stress-strain curve and the reference stress value;

[0016] A second acquisition module, used for acquiring scanning data of the reference rock sample under the first stress gradient;

[0017] An extraction module, used to extract the skeleton structure corresponding to each crack in the scan data;

[0018] A second determination module, configured to determine a first characteristic parameter value corresponding to the reference rock sample according to the skeleton structure;

[0019] A generation module is used to generate description information of the crack evolution of the first type of rock based on the first characteristic parameter value.

[0020] According to a third aspect of the present application, an electronic device is provided, including:

[0021] at least one processor; and

[0022] a memory communicatively connected to the at least one processor; wherein,

[0023] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can perform the method for characterizing crack evolution as described in the first aspect.

[0024] According to a fourth aspect of the present application, a non-transitory computer-readable storage medium storing computer instructions is provided, wherein the computer instructions are used to enable the computer to execute the method for characterizing fracture evolution as described in the first aspect.

[0025] According to a fifth aspect of the present application, a computer program product is provided, comprising computer instructions, which, when executed by a processor, implement the method for characterizing crack evolution as described in the first aspect.

[0026] The characterization method, device, electronic device and storage medium of crack evolution provided by the present application have the following beneficial effects:

[0027] First, obtain reference stress-strain curves and reference stress values ​​corresponding to multiple reference rocks, and then determine the first stress gradient corresponding to the first type of rock based on the reference stress-strain curves and reference stress values. Then, obtain the scanning data of the reference rock sample under the first stress gradient, and extract the skeleton structure corresponding to each crack in the scanning data. After that, determine the first characteristic parameter value corresponding to the reference rock sample based on the skeleton structure, and generate description information of the crack evolution of the first type of rock based on the first characteristic parameter value. Thus, by setting multiple stress gradients, determine the skeleton structure of the cracks of the rock sample under different stress gradients, and determine the characteristic parameters based on the skeleton structure to describe the evolution of the cracks in the type to which the rock sample belongs. Therefore, the crack evolution process inside the rock can be quantitatively characterized, making the description information more intuitive, which provides conditions for improving the accuracy of predicting the rock failure time and state at the time of failure, etc.

[0028] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0030] Figure 1 A schematic diagram of a flow chart of a method for characterizing crack evolution provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of a reference stress-strain curve in an embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of a skeleton structure of a single crack in an embodiment of the present application;

[0033] Figure 4 A schematic flow chart of another method for characterizing crack evolution provided in an embodiment of the present application;

[0034] Figure 5 A schematic flow chart of another method for characterizing crack evolution provided in an embodiment of the present application;

[0035] Figure 6 A schematic diagram of the structure of a crack evolution characterization device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] Embodiments of the present application 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 application, and should not be construed as limiting the present application.

[0037] The following describes the method and device for characterizing crack evolution according to an embodiment of the present application with reference to the accompanying drawings.

[0038] Figure 1 A schematic flow chart of a method for characterizing crack evolution provided in an embodiment of the present application.

[0039] like Figure 1 As shown, the characterization method of the crack evolution includes the following steps:

[0040] Step 101, obtaining reference stress-strain curves and reference stress values ​​corresponding to a plurality of reference rock samples.

[0041] Among them, multiple reference rock samples are all first type rocks, and the first type can refer to any rock type, such as coal rock, limestone or granite, etc., which is not limited in the present disclosure.

[0042] The reference stress value is the stress peak value of the reference stress-strain curve. When the stress acting on the rock is greater than the reference stress value, the main structure of the reference rock sample may be broken.

[0043] It is understandable that different types of rocks may have different mineral compositions, hardness, structures, etc., and the evolution and development process of their internal cracks under stress may be different. Therefore, in this application, it is necessary to characterize the evolution of cracks for each type of rock separately.

[0044] In the embodiment of the present application, multiple rocks can be selected from the same batch of rocks as reference rock samples. The number of reference rock samples is not fixed and can be determined according to the accuracy requirements of the evolution characterization, for example, it can be 10 rocks or 5% of the number of rocks in a batch, etc., which is not limited in the present disclosure. Then, the reference stress-strain curve and reference stress value corresponding to the reference rock sample can be obtained based on the results of the conventional uniaxial compression test conducted on each reference rock sample.

[0045] It should be noted that the same batch of rocks usually refers to rocks collected or prepared at the same time, place and conditions. Due to the consistency of the collection or preparation conditions, the rocks in the same batch have similar or identical properties. Therefore, multiple reference rock samples selected from them can be determined to be the same type of rock.

[0046] It should be noted that when the size of the reference rock samples is different, even under the same compression conditions, the evolution of the internal cracks may be quite different, which may cause errors in the reference stress-strain curve and the reference stress value. Therefore, rocks of the same size can be selected as reference rock samples, for example, rocks with a diameter of 50 mm and a height of 100 mm, etc., which is not limited in the present disclosure, to improve the characterization efficiency and accuracy of the crack evolution.

[0047] Optionally, a first stress value and a first stress-strain curve corresponding to each reference rock sample may be obtained first.

[0048] The first stress value refers to the stress acting on the rock when the main structure of the reference rock sample is broken, that is, the maximum stress that the reference rock sample can withstand.

[0049] The first stress-strain curve refers to a stress-strain curve obtained through experiments of a single reference rock sample. Because multiple reference rock samples have the same characteristics, it can be determined that multiple first stress-strain curves have the same trend and curve characteristics.

[0050] In the embodiment of the present application, a uniaxial compression test can be performed on each reference rock sample, and the strain of the reference rock sample under the uniaxial stress can be determined by continuously increasing the uniaxial stress applied to the reference rock sample, thereby obtaining a first stress-strain curve corresponding to the reference rock sample. When the main structure of the reference rock sample is broken, the first stress value can be determined based on the stress on the reference rock sample at this time.

[0051] Then, an average of the first stress values ​​may be calculated to obtain a reference stress value.

[0052] That is, the first stress values ​​corresponding to a plurality of reference rock samples may be added together, and then the added value may be divided by the number of reference rock samples to obtain a reference stress value, thereby improving the applicability and reliability of the reference stress value.

[0053] Afterwards, a reference stress-strain curve corresponding to the first type of rock may be determined according to the reference stress value and the first stress-strain curve.

[0054] It should be noted that any first stress-strain curve corresponding to the first stress value matching the reference stress value may be used as the reference stress-strain curve, or the peak value of the reference stress-strain curve may be determined as the reference stress value, and the first stress-strain curve may be integrated to obtain the reference stress-strain curve, and the present application does not limit this.

[0055] Step 102: Determine a first stress gradient corresponding to the first type of rock based on a reference stress-strain curve and a reference stress value.

[0056] Combine the following Figure 2 How to determine the first stress gradient based on the reference stress-strain curve and the reference stress value is explained. Figure 2 A schematic diagram of a reference stress-strain curve.

[0057] like Figure 2 As shown, the ordinate P represents the stress magnitude of the reference rock sample, the maximum stress is recorded as Pa, that is, the reference stress value, and the abscissa ε represents the strain of the reference rock sample under stress, that is, the degree of change in shape or volume relative to the original state. Figure 2 It can be seen from the reference stress-strain curve shown that the stress on the reference rock sample at point D is Pa stress, and the main structure of the reference rock sample is broken, so the stress on the curve segment DE drops rapidly and the strain increases.

[0058] exist Figure 2 In the curve, the inflection points O, A, B, C, D and E are the points where the internal structure of the rock changes suddenly. A curve segment can be determined between two adjacent inflection points to represent the different stages of the internal strength and internal microstructural deformation characteristics of the rock, which can be the initial pore fracture compression stage I (i.e. Figure 2 OA segment), elastic deformation stage II (i.e. Figure 2 AB segment in the middle), stable development stage of cracks III (i.e. Figure 2 BC segment in the crack), unstable crack development stage IV (i.e. Figure 2 CD segment) and post-rupture stage V (i.e. Figure 2 DE segment in ).

[0059] It should be noted that for any type of rock, its corresponding stress-strain curve can be divided into the above five stages, which is a universal property of rock stress-strain process. Moreover, for the stress-strain curve corresponding to the same type of rock, the position of the inflection point corresponding to each stage on the curve is fixed. However, in the reference stress-strain curves corresponding to different types of rocks, the position of the inflection point may be different. For example, for rock type X, point A on its reference stress-strain curve may be located at one-fifth of the curve OD, while for rock type Y, point A on its reference stress-strain curve may be located at one-sixth of the curve OD.

[0060] Optionally, a plurality of inflection points in the reference stress-strain curve may be determined first, and then the first ordinate may be determined according to the plurality of inflection points and points between every two adjacent inflection points.

[0061] The point between every two adjacent inflection points can be any point on the curve between the adjacent inflection points, such as the point on the curve corresponding to the average value of the ordinates of the adjacent inflection points. Figure 2 The dotted line on the curve represents the point on the curve.

[0062] In the embodiment of the present application, multiple inflection points in the reference stress-strain curve can be determined according to the internal structural characteristics of the first type of rock under different stresses and the tangent slopes corresponding to each point in the reference stress-strain curve, that is, Figure 2 Then, according to the coordinate system corresponding to the reference stress-strain curve, the ordinate corresponding to each inflection point and the ordinate corresponding to the point between every two adjacent inflection points can be determined to obtain the first ordinate.

[0063] It should be noted that the first ordinate may be the ordinate corresponding to all inflection points, or the ordinate corresponding to points between all inflection points, or the ordinate corresponding to some inflection points and points between inflection points, such as Figure 2 The vertical coordinates marked with a five-pointed star on the coordinate system are not limited in this disclosure. However, considering that the internal crack development characteristics of samples corresponding to different stages are very different, when characterizing the evolution process of internal cracks in rocks, at least one first vertical coordinate should be selected in each stage to determine a stress gradient.

[0064] Afterwards, the first stress gradient corresponding to the first type of rock can be obtained according to the ratio between the first ordinate and the second ordinate corresponding to the reference stress value.

[0065] Depend on Figure 2 As shown, the ratio between the first ordinate and the second ordinate corresponding to point D can be calculated to obtain the first stress gradient corresponding to the first type of rock, which may include 0, 1 / 5Pa, 1 / 3Pa, 1 / 2Pa, 2 / 3Pa, and Pa.

[0066] It should be noted that in the present application, the number of first stress gradients can be increased or decreased according to the accuracy requirements of the evolution law, the complexity and discreteness of the rock structure, etc., so as to obtain as many microstructural characteristics of rock samples under different physical fields as possible.

[0067] In the embodiment of the present application, by determining multiple first stress gradients, it is possible to avoid a single application of excessive axial stress directly causing damage to the rock sample, resulting in the description information of the crack evolution lacking the internal crack characteristics of the rock at a certain stage before the damage, thereby improving the continuity and reliability of the description of the crack evolution.

[0068] Step 103: Acquire scanning data of a reference rock sample under a first stress gradient.

[0069] Among them, scanning data refers to slice images of cracks inside rocks.

[0070] In the embodiment of the present application, an axial loading force can be applied to each reference rock sample, and the stress on the reference rock sample gradually increases from zero. Whenever the stress on the reference rock sample reaches any first stress gradient, the stress is kept constant, and a computed tomography (CT) scan is performed on the state of the reference rock sample at this time to obtain scanning data of the reference rock sample under the first stress gradient. Then, the stress is continued to be increased, and the operation of obtaining scanning data when the stress reaches any first stress gradient is repeated until the scanning data of all reference rock samples under each first stress gradient are completed.

[0071] Step 104: extract the skeleton structure corresponding to each crack in the scan data.

[0072] In the embodiment of the present application, the skeleton structure corresponding to each crack in the scanned data can be extracted by a skeleton extraction algorithm. The skeleton extraction algorithm is used for threshold processing of the scanned data, so that a binary image of the cracks in the reference rock sample can be obtained, and then an erosion operation is performed, and then an expansion is performed. By peeling off layer by layer, redundant pixels are removed, and the width information of the cracks is ignored, and only the original shape is retained, so that the skeleton structure corresponding to each crack can be obtained.

[0073] Step 105: Determine a first characteristic parameter value corresponding to the reference rock sample according to the skeleton structure.

[0074] The first characteristic parameter refers to a parameter used to quantify the geometric characteristics of a single crack structure, which may include the length, width, and inclination of the crack.

[0075] Combine the following Figure 3 How to calculate the first characteristic parameter value based on the skeleton structure of the crack is explained. Figure 3 Schematic diagram of the skeleton structure of a single crack.

[0076] In the embodiment of the present application, multiple skeleton nodes can be determined in the skeleton structure, such as Figure 3 As shown, they are Q1, Q2, ..., QN. The value of N can be determined according to the precision required for quantization and computing resources. The larger the value of N, the more accurate the calculated first characteristic parameter value will be. The position of the skeleton node on the skeleton structure can be arbitrary, and this disclosure does not limit this. Then, the first characteristic parameter value corresponding to the skeleton structure can be calculated based on the coordinates corresponding to each skeleton node.

[0077] It should be noted that a set of first characteristic parameter values ​​can be determined for each skeleton structure, and multiple skeleton structures can be proposed for each scanning data. Therefore, multiple sets of first characteristic parameter values ​​can be obtained for each reference rock sample under each first stress gradient.

[0078] Step 106: Generate description information of the fracture evolution of the first type of rock based on the first characteristic parameter value.

[0079] In an embodiment of the present application, a function can be used to fit the first characteristic parameter values ​​of multiple reference rock samples under the same first stress gradient to obtain a probability distribution of the first characteristic parameter values ​​to determine the crack condition of the first type of rock under the first stress gradient. Then, based on the change in the probability distribution of the first characteristic parameter values ​​under different first stress gradients, descriptive information on the crack evolution of the first type of rock can be obtained.

[0080] It should be noted that after generating the description information of the crack evolution of the first type of rock, the destruction time or the state at the time of destruction of other rocks belonging to the first type can be predicted based on the generated description information. In other words, the target rock to be predicted can be scanned, and then the scanning result can be matched with the description information to determine the current stage of the target rock, so as to determine whether the target rock will continue to be subjected to force and will be subject to a main fracture state, predict the destruction time of the target rock, and the state of the internal structure of the target rock when it is destroyed.

[0081] In this embodiment, a reference stress-strain curve and a reference stress value corresponding to a plurality of reference rocks are first obtained, and then a first stress gradient corresponding to a first type of rock is determined based on the reference stress-strain curve and the reference stress value. Then, the scanning data of the reference rock sample under the first stress gradient is obtained, and the skeleton structure corresponding to each crack in the scanning data is extracted. Afterwards, the first characteristic parameter value corresponding to the reference rock sample is determined according to the skeleton structure, and the description information of the crack evolution of the first type of rock is generated based on the first characteristic parameter value. Thus, by setting a plurality of stress gradients, the skeleton structure of the crack of the rock sample under different stress gradients is determined, and the characteristic parameters are determined according to the skeleton structure to describe the evolution of the crack in the type to which the rock sample belongs. Thus, the crack evolution process inside the rock can be quantitatively characterized, making the description information more intuitive, and providing conditions for improving the accuracy of predicting the rock failure time and the state at the time of failure.

[0082] Figure 4 A schematic flow chart of another method for characterizing crack evolution provided in an embodiment of the present application.

[0083] like Figure 4 As shown, the characterization method of the crack evolution may include the following steps:

[0084] Step 401, obtaining reference stress-strain curves and reference stress values ​​corresponding to a plurality of reference rock samples.

[0085] Step 402: Determine a first stress gradient corresponding to the first type of rock based on a reference stress-strain curve and a reference stress value.

[0086] Step 403: Acquire scanning data of a reference rock sample under a first stress gradient.

[0087] Step 404: extract the skeleton structure corresponding to each crack in the scan data.

[0088] For detailed description of the above steps 401 to 404, reference may be made to the above embodiments, which will not be repeated here.

[0089] Step 405 , determining a preset number of skeleton nodes on each skeleton structure.

[0090] The preset number may be determined according to the quantization accuracy requirement and computing resources, etc. The larger the preset number is, the more accurate the calculated first characteristic parameter value will be. The preset number may be N, which is a positive integer not less than 2.

[0091] In the present application embodiment, Figure 3 As shown, N skeleton nodes can be determined on each skeleton structure, namely Q1, Q2, ..., QN, Q1 and QN are respectively located at the two end points of the skeleton structure, and the positions of other skeleton nodes on the skeleton structure can be arbitrary, which is not limited in the present disclosure.

[0092] It should be noted that Figure 3 The skeleton structure shown is only a schematic diagram of a crack shape, and the skeleton structure may also be "X" or "Y" shaped, etc., which is not limited in the present disclosure. When the skeleton structure is "X" or "Y" shaped, the position of the skeleton node can be determined as the intersection of the skeleton structure.

[0093] Step 406: determine any skeleton node as the origin and establish a coordinate system to obtain the third coordinate corresponding to each skeleton node.

[0094] The third coordinate includes the horizontal coordinate and the vertical coordinate corresponding to the skeleton node in the coordinate system.

[0095] In an embodiment of the present application, since the scan data is a slice image, any skeleton node on the skeleton structure in the scan data can be determined as the coordinate origin, and a rectangular coordinate system can be established on the slice image. Then, the third coordinate corresponding to each skeleton node can be obtained based on the rectangular coordinate system.

[0096] Step 407: Calculate the distance between every two adjacent skeleton nodes according to the third coordinate and add them up to obtain the length corresponding to the skeleton structure.

[0097] In the embodiment of the present application, the distance between each two adjacent skeleton nodes can be calculated according to the third coordinate by calculus, and the obtained distances can be accumulated to determine the length corresponding to the skeleton structure. The calculation formula can be shown as follows (1):

[0098]

[0099] Among them, L represents the length corresponding to the skeleton structure, x i Indicates the horizontal coordinate of the i-th skeleton node, y i Represents the ordinate of the i-th skeleton node.

[0100] Step 408, obtaining the area of ​​the corresponding crack of the skeleton structure.

[0101] In an embodiment of the present application, the number of pixels contained in the cracks corresponding to the skeleton structure may be counted in the scan data to determine the area of ​​the cracks corresponding to the skeleton structure.

[0102] Step 409, determining the width corresponding to the skeleton structure according to the area and length.

[0103] In the embodiment of the present application, the irregular cracks can be equivalent to rectangles of equal area and length, and then the width corresponding to the skeleton structure can be calculated according to the area and length, as shown in the following formula (2):

[0104]

[0105] Among them, D represents the length corresponding to the skeleton structure, A i Represents the area of ​​the crack corresponding to the i-th skeleton structure.

[0106] Step 410: Determine the inclination angle corresponding to the skeleton structure according to the third coordinate.

[0107] In the embodiment of the present application, fitting processing can be performed according to the third coordinate, and the inclination angle of the crack corresponding to the skeleton structure can be calculated by a linear regression algorithm. The calculation formula is shown in the following formulas (3), (4), (5) and (6):

[0108] y=ax+b (3)

[0109]

[0110] θ=arctana (6)

[0111] Among them, θ is the inclination angle corresponding to the skeleton structure, and They are respectively the average values ​​of the horizontal and vertical coordinates of all skeleton nodes in a skeleton structure.

[0112] Step 411, determining the length, width and inclination as the first characteristic parameter values ​​corresponding to the reference rock sample.

[0113] In the embodiment of the present application, for each reference rock sample, multiple lengths, widths and inclinations corresponding to multiple skeleton structures can be determined under each first stress gradient. Since the length, width and inclination of rock cracks are constantly changing under different stress gradients, they can reflect the development process of the cracks. Therefore, in the present application, the length, width or inclination can be determined as the geometric characteristics of the crack structure in the quantitative reference rock sample, i.e., the first characteristic parameter value.

[0114] Step 412: Fit each type of first characteristic parameter value under each first stress gradient to obtain a first function corresponding to the type of characteristic parameter value.

[0115] In an embodiment of the present application, under each first stress gradient, each type of first characteristic parameter value (such as length, width or inclination) corresponding to the cracks contained in the reference rock sample is not a fixed value, but includes multiple different values. Therefore, each type of first characteristic parameter value can be fitted separately to obtain the first function corresponding to the type of characteristic parameter value to represent the probability distribution of the type of first characteristic parameter value.

[0116] In the present application, a negative exponential function can be used to fit the length or width to obtain a first function corresponding to the length or width, and the form of the first function is shown in formula (7). In addition, a normal distribution function can be used to fit the probability density of the inclination angle to establish a first function corresponding to the inclination angle, and the form of the first function is shown in formula (9);

[0117] f(x)=λe -λx (7)

[0118] Where λ is as shown in the following formula (8), and E(x) is the expected value of the random variable λ.

[0119]

[0120] Among them, μ x and σ x are the expectation and variance of the normal distribution respectively, and x is the independent variable of the function.

[0121] Step 413: Generate description information of the crack evolution of the first type of rock according to the change of the first function corresponding to each type of first characteristic parameter value under all first stress gradients.

[0122] For example, based on the change in the parameters of the first function corresponding to the length under all first stress gradients, the changing trend of the internal crack length distribution as the stress acting on the first type of rock increases can be determined, and then descriptive information describing the evolution of the length of the cracks in the first type of rock can be generated, such as the increase in the number of cracks with a length of millimeters, the evolution trend of the length of the most frequent cracks in the first type of rock, and so on.

[0123] In this embodiment, firstly, by calculating the length, width and inclination of each crack in the scanning data, the first characteristic parameter value corresponding to the reference rock sample is obtained, which can improve the reliability and accuracy of describing the geometric characteristics of the crack structure. Then, by fitting the first characteristic parameter value and characterizing the crack evolution of the first type of rock according to the change of the parameters in the fitted function, the accuracy of the crack evolution characterization can be further improved, making the description information more intuitive, and providing conditions for improving the accuracy of predicting the rock failure time and state at the time of failure.

[0124] Figure 5 A schematic flow chart of another method for characterizing crack evolution provided in an embodiment of the present application.

[0125] like Figure 5 As shown, the characterization method of the crack evolution may include the following steps:

[0126] Step 501, obtaining reference stress-strain curves and reference stress values ​​corresponding to a plurality of reference rock samples.

[0127] Step 502: Determine a first stress gradient corresponding to the first type of rock based on a reference stress-strain curve and a reference stress value.

[0128] Step 503: Acquire scanning data of a reference rock sample under a first stress gradient.

[0129] Step 504: extract the skeleton structure corresponding to each crack in the scan data.

[0130] Step 505: Determine a first characteristic parameter value corresponding to the reference rock sample according to the skeleton structure.

[0131] Step 506: Generate description information of the fracture evolution of the first type of rock based on the first characteristic parameter value.

[0132] For detailed description of the above steps 501 to 506, reference may be made to the above embodiments, which will not be repeated here.

[0133] It should be noted that the first characteristic parameter determined by the skeleton structure is only a separate quantification of the geometric structure of each crack, and does not take into account the overall characterization parameters of the cracks in the reference rock sample in the scanning data obtained under each first stress gradient, such as the number, density and fractal dimension of the cracks, and the description of the crack evolution of the first type of rock is not perfect. Therefore, in this application, other parameter characterizations can also be determined to improve the updated description information.

[0134] Step 507: Determine the second characteristic parameter value corresponding to the reference rock sample according to the scan data.

[0135] The second characteristic parameter value may include at least one of the following: fracture volume, fracture position coordinates, fracture quantity, fracture density and fracture fractal dimension.

[0136] It should be noted that since the cracks inside the rock have characteristics of different scales and shapes, in order to effectively and quantitatively analyze these crack structures, these irregular crack structures can usually be equated to easily measurable standard geometric bodies, and the corresponding parameters of the standard geometric bodies can be used to quantitatively characterize the crack structures.

[0137] In the present application, the crack structure can be simplified into a ball-and-stick model, where the volume of each crack is the volume of a single pixel in the scan data multiplied by the number of pixels corresponding to the crack. Then, each independent crack can be regarded as a sphere with the same volume as its own, and the coordinates of the center of the sphere are equivalent to the spatial position of the crack, that is, the position coordinates of the crack can be obtained. When calculating the number of cracks, the number of spheres of different volumes can be determined as the number of cracks of each size. In the embodiment of the present application, the scanning data is analyzed by the label module analysis model of the imaging data visualization and analysis software Avizo to obtain the volume and number of spheres, and the equivalent diameter can be obtained by formula (10);

[0138]

[0139] It should be noted that the fracture density can include one-dimensional linear density, two-dimensional surface density, and three-dimensional volume density, which are used to determine the relative proportion of the number, area, and volume of fractures within a range (such as within the slice data of a rock sample), and can be obtained by the following formulas (11), (12), and (13):

[0140]

[0141] Among them, ρ 1 is the linear density, ρ 2 is the surface density, ρ 3 is the volume density, n i is the number of cracks under the i-th first stress gradient, A iis the crack area under the i-th first stress gradient, V i is the crack volume under the i-th first stress gradient, and V is the total volume.

[0142] It should be noted that the fractal dimension of the crack can be obtained by the following formula (14):

[0143] W=log(R) / log(1 / r) (14)

[0144] Where W is the fractal dimension of the crack, R is the number of pixels around each region, and r is generally a constant representing the relative size of the region. The fractal dimension of the crack can be extracted using the Fractal Dimension module of the Avizo software.

[0145] Step 508: Update the description information based on the second characteristic parameter value.

[0146] In the embodiments of the present application, the description information under the corresponding stress gradient can be supplemented according to the second characteristic parameter value obtained under each first stress gradient, or the description information can be updated according to the change of each type of second characteristic parameter value under different first stress gradients, etc., and the present disclosure is not limited to this.

[0147] It should be noted that, in the present application, a three-dimensional visual model can also be used to characterize the changes in the cracks during axial loading, and to more intuitively reflect the feedback mechanism between internal damage and macroscopic fracture.

[0148] In an embodiment of the present application, the two-dimensional image slice sequence of each CT scan can be imported into the visualization software Avizo, and a stereoscopic image of the reference rock sample can be established using the volume rendering module. The fracture structure characteristics are then extracted through threshold segmentation and volume rendering is performed directly to establish a three-dimensional visualization model, so that the evolution process of the internal fracture structure of the rock sample during the loading process can be more intuitively observed.

[0149] In this embodiment, the second characteristic parameter value corresponding to the reference rock sample is first determined based on the scanning data, and then the description information is updated based on the second characteristic parameter value. In this way, the reliability of the description information characterizing the crack evolution process can be improved, making the description information more comprehensive and more conducive to improving the accuracy of predicting the rock failure time and state at the time of failure.

[0150] In order to implement the above embodiments, the present application also proposes a crack evolution characterization device to execute the crack evolution characterization method proposed in the above embodiments.

[0151] Figure 6 A schematic diagram of the structure of a crack evolution characterization device provided in an embodiment of the present application.

[0152] like Figure 6 As shown, the crack evolution characterization device 600 includes:

[0153] A first acquisition module 601 is used to acquire reference stress-strain curves and reference stress values ​​corresponding to a plurality of reference rock samples, wherein the plurality of reference rock samples are all first type rocks, and the reference stress value is a stress peak value of the reference stress-strain curve;

[0154] A first determination module 602 is used to determine a first stress gradient corresponding to a first type of rock based on a reference stress-strain curve and a reference stress value;

[0155] The second acquisition module 603 is used to acquire scanning data of the reference rock sample under the first stress gradient;

[0156] An extraction module 604 is used to extract the skeleton structure corresponding to each crack in the scan data;

[0157] A second determination module 605 is used to determine a first characteristic parameter value corresponding to the reference rock sample according to the skeleton structure;

[0158] The generating module 606 is used to generate description information of the fracture evolution of the first type of rock based on the first characteristic parameter value.

[0159] Furthermore, in a possible implementation, the first acquisition module 601 may be specifically configured to:

[0160] Obtaining a first stress value and a first stress-strain curve corresponding to each reference rock sample;

[0161] calculating an average value of the first stress values ​​to obtain a reference stress value;

[0162] According to the reference stress value and the first stress-strain curve, a reference stress-strain curve corresponding to the first type of rock is determined.

[0163] Further, in a possible implementation, the first determining module 602 may be specifically configured to:

[0164] determining a plurality of inflection points in a reference stress-strain curve;

[0165] Determine a first ordinate according to the plurality of inflection points and points between every two adjacent inflection points;

[0166] According to the ratio between the first ordinate and the second ordinate corresponding to the reference stress value, the first stress gradient corresponding to the first type of rock is obtained.

[0167] Further, in a possible implementation, the second determining module 605 may be specifically configured to:

[0168] Determine a preset number of skeleton nodes on each skeleton structure;

[0169] Determine any skeleton node as the origin and establish a coordinate system to obtain the third coordinate corresponding to each skeleton node;

[0170] According to the third coordinate, the distance between every two adjacent skeleton nodes is calculated and accumulated to obtain the corresponding length of the skeleton structure;

[0171] Obtain the area of ​​the crack corresponding to the skeleton structure;

[0172] Determine the width of the skeleton structure according to the area and length;

[0173] According to the third coordinate, determine the inclination angle corresponding to the skeleton structure;

[0174] The length, width and inclination are respectively determined as the first characteristic parameter values ​​corresponding to the reference rock sample.

[0175] Furthermore, in a possible implementation, the generating module 606 may be specifically configured to:

[0176] Fitting each type of first characteristic parameter value under each first stress gradient to obtain a first function corresponding to the type of characteristic parameter value;

[0177] According to the change of the first function corresponding to each type of first characteristic parameter value under all first stress gradients, descriptive information of the crack evolution of the first type of rock is generated.

[0178] Furthermore, in a possible implementation, the generating module 606 may also be used to:

[0179] Determine a second characteristic parameter value corresponding to the reference rock sample according to the scanning data, wherein the second characteristic parameter value includes at least one of a fracture volume, a fracture position coordinate, a fracture number, a fracture density, and a fracture fractal dimension;

[0180] Based on the second characteristic parameter value, the description information is updated.

[0181] It should be noted that the above explanation of the embodiment of the method for characterizing crack evolution is also applicable to the device for characterizing crack evolution of this embodiment, and will not be repeated here.

[0182] In the embodiment of the present application, a reference stress-strain curve and a reference stress value corresponding to a plurality of reference rocks are first obtained, and then the first stress gradient corresponding to the first type of rock is determined based on the reference stress-strain curve and the reference stress value. Then, the scanning data of the reference rock sample under the first stress gradient is obtained, and the skeleton structure corresponding to each crack in the scanning data is extracted. Afterwards, the first characteristic parameter value corresponding to the reference rock sample is determined according to the skeleton structure, and the description information of the crack evolution of the first type of rock is generated based on the first characteristic parameter value. Thus, by setting a plurality of stress gradients, the skeleton structure of the crack of the rock sample under different stress gradients is determined, and the characteristic parameters are determined according to the skeleton structure to describe the evolution of the crack in the type to which the rock sample belongs. Thus, the crack evolution process inside the rock can be quantitatively characterized, making the description information more intuitive, and providing conditions for improving the accuracy of predicting the rock failure time and the state at the time of failure.

[0183] In order to implement the above embodiments, the present application also proposes an electronic device, including: a processor, and a memory connected to the processor for communication; the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory to implement the characterization method of crack evolution provided in the above embodiments.

[0184] In order to implement the above embodiments, the present application also proposes a computer-readable storage medium, in which computer execution instructions are stored. When the computer execution instructions are executed by a processor, they are used to implement the characterization method of crack evolution provided by the above embodiments.

[0185] In order to implement the above embodiments, the present application also proposes a computer program product, including a computer program, which, when executed by a processor, implements the method for characterizing crack evolution provided by the above embodiments.

[0186] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this application are in compliance with relevant laws and regulations and do not violate public order and good morals.

[0187] 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.

[0188] The present application is expected to provide an implementation scheme for users to selectively block the use or access of personal information data. That is, the present disclosure is expected to provide hardware and / or software to prevent or block access to such personal information data. Once the personal information data is no longer needed, the risk 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.

[0189] 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 application. 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, without contradiction.

[0190] 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0191] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising 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 application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0192] 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 processing in other suitable ways if necessary, and then stored in a computer memory.

[0193] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: 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.

[0194] 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.

[0195] In addition, each functional unit in each embodiment of the present application 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.

[0196] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for characterizing crack evolution, characterized in that: include: Obtaining reference stress-strain curves and reference stress values ​​corresponding to a plurality of reference rock samples, wherein the plurality of reference rock samples are all first type rocks, and the reference stress value is a stress peak value of the reference stress-strain curve; Determining a first stress gradient corresponding to the first type of rock based on the reference stress-strain curve and the reference stress value; Acquire scanning data of the reference rock sample under the first stress gradient; Extracting a skeleton structure corresponding to each crack in the scan data; According to the skeleton structure, determining the first characteristic parameter value corresponding to the reference rock sample includes: determining a preset number of skeleton nodes on each skeleton structure; determining any skeleton node as the origin and establishing a coordinate system to obtain a third coordinate corresponding to each skeleton node; calculating and accumulating the distance between every two adjacent skeleton nodes according to the third coordinate to obtain the length corresponding to the skeleton structure; obtaining the area of ​​the crack corresponding to the skeleton structure; determining the width corresponding to the skeleton structure according to the area and the length; determining the inclination angle corresponding to the skeleton structure according to the third coordinate; and determining the length, the width and the inclination angle as the first characteristic parameter value corresponding to the reference rock sample respectively; Based on the first characteristic parameter value, descriptive information of the crack evolution of the first type of rock is generated, including: fitting each type of first characteristic parameter value under each first stress gradient to obtain a first function corresponding to the type of first characteristic parameter value; and generating descriptive information of the crack evolution of the first type of rock according to the change of the first function corresponding to each type of first characteristic parameter value under all first stress gradients.

2. The method according to claim 1, characterized in that The obtaining of reference stress-strain curves and reference stress values ​​corresponding to a plurality of reference rock samples includes: Obtaining a first stress value and a first stress-strain curve corresponding to each reference rock sample; calculating an average value of the first stress values ​​to obtain a reference stress value; A reference stress-strain curve corresponding to the first type of rock is determined according to the reference stress value and the first stress-strain curve.

3. The method according to claim 1, characterized in that The determining, based on the reference stress-strain curve and the reference stress value, a first stress gradient corresponding to the first type of rock comprises: determining a plurality of inflection points in the reference stress-strain curve; Determine a first ordinate according to the plurality of inflection points and points between every two adjacent inflection points; According to the ratio between the first ordinate and the second ordinate corresponding to the reference stress value, a first stress gradient corresponding to the first type of rock is obtained.

4. The method according to claim 1, characterized in that After generating description information of the crack evolution of the first type of rock based on the first characteristic parameter value, the method further includes: Determine a second characteristic parameter value corresponding to the reference rock sample according to the scanning data, wherein the second characteristic parameter value includes at least one of a fracture volume, a fracture position coordinate, a fracture number, a fracture density, and a fracture fractal dimension; Based on the second characteristic parameter value, the description information is updated.

5. A crack evolution characterization device, characterized in that: include: A first acquisition module is used to acquire reference stress-strain curves and reference stress values ​​corresponding to a plurality of reference rock samples, wherein the plurality of reference rock samples are all first type rocks, and the reference stress value is a stress peak value of the reference stress-strain curve; A first determination module, configured to determine a first stress gradient corresponding to the first type of rock based on the reference stress-strain curve and the reference stress value; A second acquisition module, used for acquiring scanning data of the reference rock sample under the first stress gradient; An extraction module, used to extract the skeleton structure corresponding to each crack in the scan data; A second determination module is used to determine the first characteristic parameter value corresponding to the reference rock sample according to the skeleton structure; wherein the second determination module is used to: determine a preset number of skeleton nodes on each skeleton structure; determine any skeleton node as the origin and establish a coordinate system to obtain a third coordinate corresponding to each skeleton node; calculate and accumulate the distance between every two adjacent skeleton nodes according to the third coordinate to obtain the length corresponding to the skeleton structure; obtain the area of ​​the crack corresponding to the skeleton structure; determine the width corresponding to the skeleton structure according to the area and the length; determine the inclination angle corresponding to the skeleton structure according to the third coordinate; determine the length, the width and the inclination angle as the first characteristic parameter value corresponding to the reference rock sample respectively; A generation module is used to generate descriptive information on the crack evolution of the first type of rock based on the first characteristic parameter value; wherein the generation module is used to: fit each type of first characteristic parameter value under each first stress gradient to obtain a first function corresponding to the type of first characteristic parameter value; and generate descriptive information on the crack evolution of the first type of rock according to the changes of the first function corresponding to each type of first characteristic parameter value under all first stress gradients.

6. An electronic device, characterized in that: include: 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 for characterizing crack evolution according to any one of claims 1-4.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method for characterizing crack evolution according to any one of claims 1 to 4.

8. A computer program product, characterized in that It comprises a computer program, which, when executed by a processor, implements the method for characterizing crack evolution according to any one of claims 1 to 4.

Images