Method for constructing crushed particle clusters in gangue compaction process

Abstract

The invention discloses a method for constructing a crushed particle cluster in a gangue compaction process, which comprises the following specific steps of: firstly, acquiring a longitudinal section image of dyed gangue in a compression process, and then processing the image through a self-compiled program to acquire digital characteristics of crushed particles in the gangue compaction process; and finally, importing the obtained shape and position information of the crushed particles into numerical simulation software to realize the construction of the crushed particle cluster in the gangue compaction process. According to the method, the limitation that the geometry reflecting the real shape of the crushed particles is difficult to establish in simulation software is overcome, the combination of the modeling of the real-shape gangue particles and the indoor gangue compression test is realized, and an effective way is provided for deeply researching the micro-mechanical behavior and the deformation failure mechanism in the gangue bearing compression process.

Description

Technical Field

[0001] The invention relates to the technical field of filling mining, and in particular to a method for constructing broken particle clusters in a gangue compaction process. Background Art

[0002] During the compression of bulk gangue, gangue particles are broken into irregular blocks. Existing numerical simulation software based on discrete element method, such as PFC (Particle Flow Code), can only generate regular spherical particles. The two existing methods for modeling irregular blocks are mainly based on algorithm development, using programming language to develop arbitrary concave and convex polygons, and randomly reconstructing the shape of particles. The construction and analysis of arbitrary polygonal particles based on algorithm programs cannot reflect the actual situation of gangue particles breaking into irregular blocks, and the random placement of particles is quite different from indoor experiments. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a method for constructing broken particle clusters during the compaction process of gangue, so as to achieve high-reduction generation of irregular blocks formed by crushing during the compaction process of gangue in numerical simulation software.

[0004] Technical solution: A method for constructing broken particle clusters during gangue compaction, comprising the following steps:

[0005] S1, obtaining the longitudinal section image of dyed gangue during compression;

[0006] S2, obtaining digital features of broken particles during the gangue compaction process, importing the digital features into AutoCAD software to generate broken particle contours and saving and outputting them as .dxf files;

[0007] S3, using the particle flow program and .dxf files, construct the real crushed particle clusters during the gangue compaction process.

[0008] 2. The method for constructing broken particle clusters during gangue compaction according to claim 1 is characterized in that the steps of obtaining the longitudinal section image during the compression of dyed gangue are as follows:

[0009] S11, screening the gangue particles into different particle size intervals;

[0010] S12, using a dye to dye the gangue in each particle size range into different colors;

[0011] S13, dyed gangue of different colors are loaded into a steel cylinder according to natural grading, and a confined compression test is carried out with a loading rate of 2 mm / s and a maximum pressure value of 15 MPa to obtain a gangue aggregate; after the test, the steel cylinder is opened, the gangue aggregate is separated along the longitudinal section, and a camera is used to take a picture to obtain a longitudinal section image of the dyed gangue during the compression process.

[0012] Furthermore, in step S12, the dye penetrates into the dyed gangue to a depth of 3 to 8 mm.

[0013] Further, in step S2, the digital features include shape and position information; the longitudinal section image of the dyed gangue during the compression process is binarized using Matlab software to obtain a binarized image; code is written to detect the edges of the binarized image and extract the contours of the broken gangue particles; finally, the find function is used to calculate the global coordinates of the contour points from the positions of the contour points, and the global coordinate information of all contour points is imported into AutoCAD software to generate the contours of the broken particles and saved as a .dxf file.

[0014] Furthermore, in step S3, the steps for constructing the real broken particle clusters in the gangue compaction process are as follows:

[0015] S31, using the particle flow program to establish a model boundary with the same size as the steel cylinder to simulate the rigid wall;

[0016] S32, generating spherical particles within the model boundary;

[0017] S33, importing the .dxf file to generate a polygonal geometry that can represent the true shape of the crushed particles; grouping the spherical particles according to the shape of the polygonal geometry, and deleting the redundant particles that are not in the polygonal geometry, so as to generate a cluster of real crushed particles in the gangue compaction process.

[0018] Compared with the prior art, the present invention has the following significant effects:

[0019] The present invention screens gangue particles into different particle size intervals, and realizes the combination of modeling of gangue particles with real shapes and indoor gangue compression tests by generating irregular blocks formed by the crushing during the gangue compaction process with high reduction in numerical simulation software, thereby overcoming the limitation that it is difficult to establish a geometric body reflecting the real shape of the crushed particles in the simulation software, and providing an effective way to deeply study the mesoscopic mechanical behavior and deformation and failure mechanism of the gangue in the process of bearing compression; a particle cluster reflecting the real geometric shape of the crushed particles is constructed in the PFC software, and the crushing of the particles under the pressure of the overlying rock strata after the gangue is filled into the goaf of the coal mine is simulated, so that the shape of the gangue after crushing can be accurately known, and technical support is provided for studying the mesoscopic mechanical behavior and deformation and failure mechanism of the loose coal gangue particle carrier in the process of solid filling coal mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flow chart of the present invention;

[0021] Figure 2 A schematic diagram of a steel cylinder used in an embodiment of the present invention;

[0022] Figure 3 This is a flow chart of importing a .dxf file into the particle flow program PFC to construct a real broken particle cluster during the gangue compaction process in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0026] like Figure 1 As shown, a method for constructing a broken particle cluster in a gangue compaction process comprises the following specific steps:

[0027] Step 1, obtaining a longitudinal cross-sectional image of dyed gangue during compression;

[0028] First, the gangue particles are screened into 6 particle size intervals: 5-10 mm, 10-15 mm, 15-20 mm, 20-30 mm, 30-40 mm and 40-50 mm;

[0029] Then, the gangues of the six particle size ranges were dyed into original color (i.e., undyed), khaki, black, sky blue, grass green, and jujube red using SINO-401 stone dye; dyed gangues were prepared using a strong penetrating stone dye, and the dyes penetrated into a certain depth (about 3 to 8 mm) inside the dyed gangues;

[0030] Finally, the dyed gangue of different colors is loaded into the steel cylinder according to the natural gradation (such as Figure 2 A confined compression test was carried out on a steel cylinder (as shown in the figure). Under the pressure of the press, the pressure rod can move up and down in the steel cylinder to compress the gangue. The loading rate is 2 mm / s, and the experiment is ended when the pressure value is 15 MPa to obtain a gangue aggregate. The circular cylinder wall of the steel cylinder is composed of two semicircular side walls on the left and right that are locked by bolts. After the test, the steel cylinder is opened, the gangue aggregate is separated along the longitudinal section, and a canno-80DC camera is used to take pictures to obtain a longitudinal section image of the dyed gangue during the compression process.

[0031] Step 2, obtaining digital features of broken particles during the gangue compaction process;

[0032] The longitudinal section image of the dyed gangue during the compression process is binarized using Matlab software to obtain a binary image. Code is written to detect the edges of the binary image, extract the contours of the broken gangue particles, convert each contour point into a global coordinate, obtain the shape and position information of the broken particles, and import the shape and position information of the broken particles into AutoCAD software to generate the broken particle contours and save the output as a .dxf file.

[0033] In Matlab software, the rgb2gray function is used to convert the longitudinal section image of the dyed gangue during the compression process into a grayscale image, and then the imbinarize function is used to convert the grayscale image into a binary image; the edge and bwboundaries functions are used to perform edge detection and contour extraction on the binary image to obtain the geometric boundary reflecting the true shape of the broken particles; the find function is used to convert the position of the contour points on each geometric boundary into global coordinates, and the global coordinate information of all contour points (i.e. the shape and position information of the broken particles) is imported into AutoCAD software to generate the broken particle contour and save the output as a .dxf file.

[0034] Step 3, constructing the real broken particle clusters during the gangue compaction process;

[0035] like Figure 3 As shown in the figure, the particle flow program PFC is used to establish a model boundary with the same size as the steel cylinder to simulate the rigid wall, and spherical particles are generated within the range of the model boundary; finally, the .dxf file obtained in step 2 is imported to generate a specified geometry that can represent the true shape of the broken particles (i.e. Figure 3 The polygonal geometry that reflects the real shape of the crushed gangue shown in is used to group the spherical particles according to the specified geometry shape, and delete the redundant particles that are not within the boundary of the specified geometry to generate the real crushed particle clusters in the gangue compaction process.

[0036] Firstly, a model boundary with the same size as the steel cylinder is established in the particle flow code (PFC) to simulate a rigid wall, and the distribute command is used to generate spherical particles within the model boundary. Then, the geometry command is used to import the .dxf file into PFC, read the polyline boundary of the broken particles and generate the specified polygonal geometry. Finally, the ball group command is used to group the spherical particles according to the range of the polygonal geometry, and delete the redundant particles that are not in any polygonal geometry (to obtain pores), so as to generate the real broken particle clusters in the gangue compaction process.

Claims

1. A method for constructing broken particle clusters during gangue compaction, characterized in that: The steps include: S1, obtaining the longitudinal section image of dyed gangue during compression; S2, obtaining digital features of broken particles during the gangue compaction process, importing the digital features into AutoCAD software to generate broken particle contours and saving and outputting them as .dxf files; S3, using the particle flow program and .dxf files, construct the real crushed particle clusters during the gangue compaction process.

2. The method for constructing broken particle clusters during gangue compaction according to claim 1, characterized in that: The steps for obtaining the longitudinal section image of dyed gangue during compression are as follows: S11, screening the gangue particles into different particle size intervals; S12, using a dye to dye the gangue in each particle size range into different colors; S13, dyed gangue of different colors are loaded into a steel cylinder according to natural grading, and a confined compression test is carried out with a loading rate of 2 mm / s and a maximum pressure value of 15 MPa to obtain a gangue aggregate; after the test, the steel cylinder is opened, the gangue aggregate is separated along the longitudinal section, and a camera is used to take a picture to obtain a longitudinal section image of the dyed gangue during the compression process.

3. The method for constructing broken particle clusters during gangue compaction according to claim 2, characterized in that: In step S12, the dye penetrates into the dyed gangue to a depth of 3 to 8 mm.

4. The method for constructing broken particle clusters during gangue compaction according to claim 1, characterized in that: In step S2, the digital features include shape and position information; the longitudinal section image of the dyed gangue during the compression process is binarized using Matlab software to obtain a binarized image; code is written to detect the edges of the binarized image and extract the contours of the broken gangue particles; finally, the find function is used to calculate the global coordinates of the contour points from the positions of the contour points, and the global coordinate information of all contour points is imported into AutoCAD software to generate the contours of the broken particles and saved as a .dxf file.

5. The method for constructing broken particle clusters during gangue compaction according to claim 1, characterized in that: In step S3, the steps for constructing the real broken particle clusters in the gangue compaction process are as follows: S31, using the particle flow program to establish a model boundary with the same size as the steel cylinder to simulate the rigid wall; S32, generating spherical particles within the model boundary; S33, importing the .dxf file to generate a polygonal geometry that can represent the true shape of the crushed particles; grouping the spherical particles according to the shape of the polygonal geometry, and deleting the redundant particles that are not in the polygonal geometry, so as to generate a cluster of real crushed particles in the gangue compaction process.

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