Method and system for generating two-dimensional random blocks in soil-rock mixture

Abstract

The present invention provides a method and system for generating two-dimensional random blocks in a soil-rock mixture, and the method comprises: step 1, determining a rectangular boundary surface according to the actual size of the soil-rock mixture to be simulated; step 2, taking a small amount of local sampling, performing a screening test, obtaining a particle grading curve, and then obtaining a cumulative distribution function of the block size, and using Latin hypercube sampling to generate a series of different semi-major axes; step 3, generating a series of different semi-minor axes corresponding to the semi-major axes according to the probability distribution obeyed by the ratio of the minor axis to the major axis; step 4, randomly generating the center coordinates of an ellipse in the rectangular boundary surface, and any two ellipses do not overlap; step 5, generating an inscribed arbitrary polygon in the ellipse as a block; step 6, calculating the current block content in the rectangular boundary surface based on the specific gravity of the soil and the block; step 7, rotating the generated block by an arbitrary angle; step 8, repeating steps 4 to 7 until the current block content in the rectangular boundary surface meets the error ε requirement.

Description

Technical Field

[0001] The invention belongs to the technical field of random block generation of materials, and in particular relates to a method and system for generating two-dimensional random blocks in a soil-rock mixture. Background Art

[0002] Soil-Rock Mixture (S-RM) refers to a heterogeneous geological material composed of soil and rock blocks, which is widely distributed around the world. Due to the presence of rocks of different contents, sizes, shapes, and orientations, the macroscopic mechanical properties of soil-rock mixtures are very complex. Research on the mechanical behavior and deformation characteristics of soil-rock mixtures will help us better understand this geological material, reduce or avoid the occurrence of natural disasters such as landslides and collapses, extend the service life of geological engineering, and protect human life and property safety.

[0003] At present, there are two main methods for studying the macroscopic mechanical properties of soil-rock mixtures: experiments and numerical simulations. Among them, experiments can be divided into field experiments and indoor experiments. Although field experiments can more accurately and truly reflect the mechanical properties of soil-rock mixtures, the costs of equipment, labor, time, etc. involved are relatively high, so indoor experiments and numerical simulations have become two economically feasible methods. The numerical simulation calculation results can be compared and analyzed with the indoor test results, which is conducive to better summarizing the specific laws of soil-rock mixtures.

[0004] However, the input of geometric parameters of soil-rock mixture has become a key point that hinders numerical simulation experiments. Directly using image scanning technology (such as CT scanning) can obtain the geometric shape of the real block, or taking a photo of the block and then using image processing technology such as Gaussian blur to obtain the geometric shape of the block. Although these technologies can obtain the geometric parameters of the block, they are not cost-effective: image scanning technology is generally expensive and requires the guidance of professionals, and safety issues such as radiation also need to be paid attention to; taking photos of the block and processing the photos is complicated and inefficient.

[0005] In order to generate a soil-rock mixture model in a limited area (such as a rectangular boundary surface or a slope boundary surface), it is necessary to establish a block stone database (which contains a large number of data parameters of the geometric shape of blocks), and then randomly select blocks from the database and place them in the limited area until the block stone content reaches the corresponding requirements. Establishing a block stone database requires a lot of manpower and material resources, and it is difficult to ensure the uniformity of block stone distribution when placing them in irregular areas.

[0006] Therefore, it is necessary to propose a cost-effective, simple and easy method and system for generating two-dimensional random blocks in soil-rock mixture. Summary of the invention

[0007] The present invention is made to solve the above problems, and aims to provide a method and system for generating two-dimensional random blocks in a soil-rock mixture, which can conveniently and efficiently generate a soil-rock mixture model for soil-rock mixtures with different geometric and physical properties.

[0008] In order to achieve the above purpose, the present invention adopts the following scheme:

[0009] <Method>

[0010] The present invention provides a method for generating two-dimensional random blocks in a soil-rock mixture, wherein no image scanning is required during the processing, and the method is characterized in that the method comprises the following steps:

[0011] Step 1, determining the rectangular boundary surface and the rock block threshold according to the actual size of the soil-rock mixture to be simulated;

[0012] Step 2, a small amount of sampling is taken from a local part of the soil-rock mixture to be simulated, and a screening test is performed to obtain a particle grading curve. According to the particle grading curve, the distribution of the block stones in different particle size ranges is obtained, and then the cumulative distribution function of the block stone particle size is obtained. A series of different semi-major axes are generated by using the Latin hypercube sampling method, so that the frequency distribution of this series of semi-major axes is consistent with the probability distribution;

[0013] Step 3, generating a series of different semi-minor axes corresponding to the semi-major axes from the probability distribution obeyed by the ratio of the minor axis to the major axis, so that the frequency distribution of the series of semi-minor axes is consistent with the probability distribution;

[0014] Step 4: Based on steps 2 and 3, randomly generate the center coordinates of the ellipse within the rectangular boundary surface, and ensure that any two ellipses do not overlap;

[0015] Step 5, generating an inscribed arbitrary polygon in the ellipse as a simulated stone block;

[0016] Step 6, calculating the current rock content within the rectangular boundary surface based on the specific gravity of the soil and rock;

[0017] Split the stone into multiple triangles with the center of the ellipse as the common vertex, calculate the area of ​​each triangle and sum them up to get the area of ​​a certain n-gonal stone, and then sum the areas of all the stones within the rectangular boundary surface:

[0018]

[0019] In the formula, S rock , S ij They represent the total area of ​​the blocks and the area of ​​the jth triangle of the ith block, respectively, and m represents the total number of blocks. Thus, the current content of the blocks can be obtained as:

[0020]

[0021] In the formula, F m ' ass 、F a ' rea They represent the mass ratio (physical parameter) and area ratio (geometric parameter) of the current stone block within the rectangular boundary surface; S 矩形边界面 Represents the area of ​​the rectangular boundary surface; G s_soil , G s_rock They represent the measured soil specific gravity and rock specific gravity of the sample respectively;

[0022] Step 7, rotate the generated stone block to any angle using the coordinate rotation matrix;

[0023] Step 8, repeat steps 4 to 7 until the current rock content within the rectangular boundary surface meets the error ε requirement:

[0024]

[0025] Preferably, the method for generating two-dimensional random blocks in a soil-rock mixture provided by the present invention may also have the following characteristics: in step 1, if the soil-rock mixture to be simulated is a slope, then after step 8, further execute: step 9, draw the slope boundary line, remove the blocks outside the slope boundary line, and retain the blocks within the slope boundary line.

[0026] Preferably, the method for generating two-dimensional random blocks in a soil-rock mixture provided by the present invention may also have the following feature: the shape of the slope surface may be any complex shape.

[0027] Preferably, the method for generating two-dimensional random blocks in a soil-rock mixture provided by the present invention may further include: step 10, storing coordinate information of all blocks to construct a model of the soil-rock mixture in numerical simulation software.

[0028] Preferably, the method for generating two-dimensional random blocks in a soil-rock mixture provided by the present invention may also have the following feature: in step 8, ε=5e-4.

[0029] Preferably, the method for generating two-dimensional random blocks in a soil-rock mixture provided by the present invention may also have the following characteristics: in step 1, the length and width of the rectangular boundary surface are not limited to the size of the sample in the indoor triaxial test, but should be determined according to the actual size of the simulation object, for example, it can be set to the size of the sample in the direct shear test. The block threshold includes a minimum particle size (soil / stone threshold) and a maximum particle size.

[0030] <System>

[0031] Furthermore, the present invention also provides a two-dimensional random block generation system in a soil-rock mixture, characterized in that it includes:

[0032] A parameter determination unit determines a rectangular boundary surface and a rock block threshold according to the actual size of the soil-rock mixture to be simulated;

[0033] The gradation curve acquisition part takes a small amount of samples from a local part of the soil-rock mixture to be simulated, performs a screening test, and obtains a particle gradation curve;

[0034] The semi-major axis generation part obtains the distribution of the block in different particle size ranges according to the particle grading curve, and then obtains the cumulative distribution function of the block particle size. The Latin hypercube sampling method is used to generate a series of different semi-major axes, so that the frequency distribution of this series of semi-major axes is consistent with the probability distribution.

[0035] A semi-minor axis generating unit generates a series of different semi-minor axes corresponding to the semi-major axes from the probability distribution obeyed by the ratio of the minor axis to the major axis, so that the frequency distribution of the series of semi-minor axes is consistent with the probability distribution;

[0036] The center generation part randomly generates the center coordinates of the ellipse within the rectangular boundary surface based on the generated series of semi-major axes and semi-segment axes, and ensures that any two ellipses do not overlap;

[0037] A block stone generating part generates an inscribed arbitrary polygon in the ellipse as a simulated block stone;

[0038] The content determination part calculates the current rock content based on the specific gravity of the soil and rock; splits the rock into multiple triangles with the center of the ellipse as the common vertex, calculates the area of ​​each triangle and sums them up to get the area of ​​a certain n-sided rock, and then sums the areas of all the rocks within the rectangular boundary surface:

[0039]

[0040] In the formula, S rock , S ij Respectively represent the total area of ​​the block, the area of ​​the jth triangle of the ith block, and m represents the total number of blocks; thus, the content of the block can be obtained as:

[0041]

[0042] In the formula, F m ' ass 、F a ' rea Respectively represent the mass ratio and area ratio of the current generation; S 矩形边界面 Represents the area of ​​the rectangular boundary surface; G s_soil , G s_rock They represent the measured soil specific gravity and rock specific gravity of the sample respectively;

[0043] The rotation part rotates the generated stone blocks to any angle through the coordinate rotation matrix;

[0044] The error judgment unit judges whether the current block content up to the rectangular boundary surface meets the error ε requirement:

[0045]

[0046] The control unit is connected to the parameter determination unit, the grading curve acquisition unit, the semi-major axis generation unit, the semi-minor axis generation unit, the center generation unit, the block generation unit, the content determination unit, the rotation unit, and the error judgment unit, and controls their operation;

[0047] Among them, the control unit controls the center generation unit, the block stone generation unit, the content determination unit, the rotation unit, and the error judgment unit to run in a loop until the error judgment unit determines that the block stone content of the current rectangular boundary surface meets the error ε requirement, and outputs the block stone model filled in the rectangular boundary surface.

[0048] Preferably, the two-dimensional random block stone generation system in the soil-rock mixture provided by the present invention also includes: a drawing unit, which is communicatively connected with the control unit. For the case where the soil-rock mixture to be simulated is a slope, after obtaining the block stone model filled in the rectangular boundary surface, based on the actual shape of the slope to be simulated, the corresponding slope boundary line is drawn, and the blocks outside the slope boundary line are removed from the block stone model filled in the rectangular boundary surface, and the blocks within the slope boundary line are retained, and the output is a random block stone model of the slope.

[0049] Preferably, the two-dimensional random block generation system in the soil-rock mixture provided by the present invention may also have the following feature: the slope surface shape can be any complex shape.

[0050] Preferably, the device for generating two-dimensional random blocks of stone in a soil-rock mixture provided by the present invention may further include: a storage unit, which is communicatively connected to the control unit, and performs post-processing on the coordinate information of all blocks of stone in the model and stores it as data information.

[0051] Preferably, the two-dimensional random block generation system in the soil-rock mixture provided by the present invention may also have the following characteristics: an input display unit is communicatively connected with the control unit to allow the operator to input operation instructions and perform corresponding display.

[0052] Preferably, the two-dimensional random block generation system in the soil-rock mixture provided by the present invention may also have the following feature: ε=5e-4.

[0053] Functions and Effects of the Invention

[0054] The method and system for generating two-dimensional random blocks in a soil-rock mixture provided by the present invention do not require image scanning, photographing, and complex calculation (Gaussian blur, etc.) processing, but only require a small amount of sampling for screening test to obtain a particle grading curve, and then obtain a cumulative distribution function of the block size, and then use the Latin hypercube sampling method to generate a series of semi-major axes consistent with the frequency distribution and probability distribution, and then generate a series of different semi-minor axes corresponding to the semi-major axes from the probability distribution obeyed by the ratio of the minor / major axis, and generate an inscribed arbitrary polygon in the ellipse as a simulated block, and then calculate the current block content based on the specific gravity of the soil and the block, rotate the block to any angle, and repeat the cycle until the block content in the current simulated boundary surface meets the error requirements, so as to obtain a two-dimensional random block model that meets the requirements of grading, shape, content, orientation, etc. The operation of the processing process is safe and simple; for soil-rock mixtures with different geometric and physical characteristics, an accurate soil-rock mixture model can be obtained conveniently and quickly by only modifying the parameter values.

[0055] For slope simulation, the present invention can simulate slopes of any shape by drawing slope boundary lines, removing rocks outside the slope boundary lines, and retaining rocks within the slope boundary lines. Even if the slope surface is very complex, this method can still efficiently and accurately obtain a two-dimensional slope random rock model. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a flow chart of a method for generating two-dimensional random blocks of stone in a soil-rock mixture according to an embodiment of the present invention;

[0057] Figure 2 A diagram of a GDS large-scale specimen dynamic and static triaxial test system located in the Water Engineering Risk and Disaster Prevention Laboratory of the Hydropower Science and Technology Building of Wuhan University involved in an embodiment of the present invention;

[0058] Figure 3 Schematic diagram of different particle grading curves involved in Example 1 of the present invention;

[0059] Figure 4 The cumulative distribution function curve of the block stone particle size and the related parameter diagram involved in the first embodiment of the present invention;

[0060] Figure 5 The probability density function curve and related parameter diagram of the short / long axis ratio η=b / a involved in the first embodiment of the present invention;

[0061] Figure 6 This is a schematic diagram of generating an inscribed arbitrary polygon in the i-th ellipse according to the first embodiment of the present invention;

[0062] Figure 7Schematic diagram of part of the process of measuring the specific gravity of a rock mass involved in the first embodiment of the present invention; wherein, (a) the rock mass is grouped according to the particle size range; (b) the rock mass is crushed into particles so as to be loaded into a pycnometer; (c) water is poured into the pycnometer; (d) the mass of the pycnometer + water is measured; (e) the mass of the pycnometer + water + rock mass is measured;

[0063] Figure 8 A schematic diagram of a coordinate rotation transformation involved in the second embodiment of the present invention;

[0064] Fig. 9 The two-dimensional random block stone result diagram (unit: mm) of the second embodiment of the present invention with a content of 40.00% is generated: (a) "ellipse + non-rotation" block stone (actual content 40.003%); (b) "ellipse + rotation" block stone (actual content 40.003%); (c) "polygon + non-rotation" block stone (actual content 40.012%); (d) "polygon + rotation" block stone (actual content 40.0029%);

[0065] Fig.10 It is a schematic diagram of storing block stone coordinate information for subsequent numerical simulation involved in the second embodiment of the present invention;

[0066] Fig.11 Schematic diagram of a two-dimensional slope structure involved in the second embodiment of the present invention (unit: dm);

[0067] Fig.12 A cumulative distribution function curve of the block stone particle size used in the two-dimensional slope involved in the second embodiment of the present invention;

[0068] Fig.13 This is a result diagram (unit: dm) of generating a two-dimensional slope random block stone with a content of 55.00% involved in Example 2 of the present invention: (a) generating blocks of stone within a rectangular boundary (the simulated generated content is 55.02%); (b) drawing the boundary line of the slope; (c) removing the blocks outside the boundary line; (d) obtaining a two-dimensional slope random block stone;

[0069] Fig.14 A slope diagram of a soil-rock mixture exposed at a certain place in Bafen Mountain, Jiangxia District, Wuhan City, Hubei Province, involved in the second embodiment of the present invention;

[0070] Fig.15 Schematic diagram of the complex two-dimensional slope structure involved in the second embodiment of the present invention (unit: dm): (a) regular slope surface; (b) irregular slope surface. DETAILED DESCRIPTION

[0071] The specific implementation scheme of the method and system for generating two-dimensional random blocks of stone in a soil-rock mixture according to the present invention will be described in detail below with reference to the accompanying drawings.

[0072] <Example 1>

[0073] In this embodiment, taking the generation of two-dimensional random blocks that meet the requirements of grading, shape, content, orientation, etc. in a sample of 150mm×300mm size as an example (this embodiment uses Matlab to write the corresponding code), the technical principle of the present invention is further explained.

[0074] like Figure 1 As shown, the method for generating two-dimensional random blocks in a soil-rock mixture provided in this embodiment includes the following steps:

[0075] Generate two-dimensional random blocks within a sample size of 150 mm × 300 mm, including the following steps:

[0076] S1: Determine the soil / rock threshold for distinguishing soil and rock, and limit the maximum particle size of rock. S / RT =0.05L c , where L c Indicates the engineering characteristic scale of the soil-rock mixture (for triaxial test specimens, it is taken as the specimen diameter); the maximum particle size of the block in the triaxial test d max It should be less than 1 / 5 of the sample diameter. For a sample with a diameter of 150 mm, d can be calculated as S / RT =7.5mm, d max =30mm.

[0077] S2: Based on the particle grading curve, the Latin hypercube sampling method is used to generate different semi-major axes a. Figure 3 The figure shows a schematic diagram of different particle grading curves. Based on the particle grading curves, the distribution of blocks in different particle size ranges can be obtained. In this embodiment, blocks in the five particle size ranges of 7.5-10mm, 10-15mm, 15-20mm, 20-25mm, and 25-30mm account for 10%, 10%, 50%, 20%, and 10% of the total amount of blocks, respectively. Based on this, a cumulative distribution function curve of the block size can be drawn, such as Figure 4 As shown. The Latin hypercube sampling method is used to generate a series of block stone particle sizes that obey the cumulative distribution function, and the semi-major axis a is equal to 1 / 2 times the block stone particle size. Figure 4 As can be seen from the illustration in the figure, the range of the semi-major axis a is: 0.5d S / RT ~0.5d max In order to ensure that the statistical results of a series of major axes are consistent with the cumulative distribution function of the stone particle size and to ensure that the number of ellipses placed in the rectangular boundary later meets the requirements, the total number of semi-major axes generated here should be as large as possible (10,000 can be generated).

[0078] S3: Based on the values ​​of the semi-major axis a generated, the corresponding value of the semi-minor axis b is determined by the ratio of the minor axis to the major axis η = b / a. For an ellipse (or circle), the ratio of the minor axis to the major axis is less than or equal to 1; since the lower bound of the particle size of the block is d S / RT , so the semi-minor axis b must be greater than or equal to 0.5d S / RT , that is, the ratio of the short axis to the long axis is greater than or equal to 0.5d S / RT / a. In this embodiment, η is assumed to follow the normal distribution N(μ,σ 2 ), whose mean μ is equal to 0.5d S / RT / a+ξΔ, where ξ is a proportional coefficient between 0 and 1, and is 0.25 in this embodiment, and Δ is the length of the value interval of η, that is, Δ=1-0.5d S / RT / a, and the standard deviation σ is taken as 0.1. Figure 5 It is a graph of the probability density function curve of the short / long axis ratio η = b / a and related parameters. It should be pointed out that the range of values ​​of a random variable that obeys a normal distribution is from negative infinity to positive infinity. When the short / long axis ratio exceeds [0.5d S / RT / a,1], the value must be discarded and regenerated, which can be achieved in Matlab through the while statement:

[0079] while ratio_of_short_axis_and_long_axis<ratio_min||ratio_of_short_axis_and_long_axis> ratio_max

[0080] ratio_of_short_axis_and_long_axis=normrnd((ratio_min+(ratio_max-ratio_min) / 4),0.1);

[0081] end

[0082] Among them, ratio_of_short_axis_and_long_axis means η=b / a, ratio_min means 0.5d S / RT / a, ratio_max represents 1, and normrnd is a function used in Matlab to generate random numbers that obey the normal distribution.

[0083] S4: Randomly generate the center coordinates of ellipses within the 150mm×300mm rectangular boundary surface to determine the position of the ellipses, and ensure that the ellipses do not overlap with each other. Randomly select a number of ellipses from the 10,000 ellipses generated above for placement. Let the center coordinates of the i-th ellipse be (x i ,y i), in order to ensure that all ellipses are within the 150mm×300mm rectangular boundary surface (not penetrating or exceeding the boundary), it is necessary to define x i ,y i If the 150mm direction is the x-axis and the 300mm direction is the y-axis, then x i ,y i The values ​​of are (taking the lower left corner of the rectangular boundary surface as the origin):

[0084] x i =a i +(150-2a i )*rand,y i =a i +(300-2a i )*rand (3)

[0085] In the formula, a i is the semi-major axis of the i-th ellipse, and rand represents a random number uniformly distributed between 0 and 1. When the first ellipse is generated, there is no need to judge the overlap between ellipses, but for the i-th (≥2) ellipse, it must be ensured that it does not overlap with the previous i-1 ellipses. The following formula is the necessary and sufficient condition for non-overlap:

[0086]

[0087] In the formula, (x h ,y h ) is the center coordinate of the hth ellipse, a h is the semi-major axis of the hth ellipse. For the i-th (≥2) ellipse, if equation (2) is not satisfied, the center coordinates (x i ,y i ) until the condition of formula (2) is satisfied.

[0088] S5: Generate an inscribed arbitrary polygon in the ellipse. Figure 6 As shown, generate an arbitrary n (≥3)-gon inscribed in the i-th ellipse. To generate an n-gon, n different angles must be given Then, rays are emitted from the center of the ellipse and intersect the ellipse at point (x ij ,y ij ), from the ellipse equation, the coordinates of the intersection point are:

[0089]

[0090] Where b i is the semi-minor axis of the i-th ellipse. In this case, it is assumed that: n is a random integer uniformly distributed between 10 and 15; A random number that is uniformly distributed between 0 and 360 degrees. To connect n intersections into a closed polyline segment, these intersections must be arranged counterclockwise or clockwise, that is, the n angle values ​​are arranged in order from small to large or from large to small. In this embodiment, counterclockwise arrangement is adopted.

[0091] S6: Continuously add rocks, and calculate the actual rock content by considering the specific gravity of soil and rocks, until the actual rock content exceeds the given requirement. For a given rock content, it is actually the ratio of the mass of the rock to the total mass of the soil-rock mixture, and the present invention reflects the area ratio in the graph. Therefore, the mass ratio should be converted into the area ratio according to the specific gravity of the soil and rocks:

[0092]

[0093] Among them, F area 、F mass Respectively represent the ratio of area and mass, G s_soil , G s_rock They represent the specific gravity of soil and the specific gravity of stone respectively. Figure 7 Table 1 gives some of the steps involved in determining the specific gravity of a rock: G s_rock =2.69. Similarly, the average specific gravity of the soil can be measured, G s_soil =1.20.

[0094] Table 1 Results of determination of specific gravity of stone

[0095]

[0096] Split any polygonal block into multiple triangles with the center of the ellipse as the common vertex, calculate the area of ​​each triangle and sum them up to get the area of ​​a certain n-gonal block, and then sum the areas of several blocks:

[0097]

[0098] In the formula, S rock , S ij Respectively represent the total area of ​​the block and the area of ​​the jth triangle of the ith block, and m represents the total number of blocks. It should be pointed out that formula (5) can also be used to calculate the area of ​​an ellipse, just split the ellipse into several triangles to calculate the area. Thus, the content of the block can be obtained as:

[0099]

[0100] In the formula, F m ' ass 、F a ' reaRepresent the actual mass ratio and area ratio respectively. Using the break statement in Matlab, once the actual block content is greater than or equal to the given block content value, the block generation is terminated, and the total number of blocks m is also determined here.

[0101] S7: The orientation of the stone is uncertain, so a rotation algorithm must be added. ij ,y ij ) around the center of the ellipse (x i ,y i ) is rotated by an angle α, and the coordinate point after rotation (x i ' j ,y i ' j )for:

[0102]

[0103] Figure 8 A schematic diagram of coordinate rotation transformation is given.

[0104] S8: The entire code is looped continuously until the actual block stone content meets the error requirements. In order to make the actual generated block stone content close to the given block stone content, the entire code is looped continuously until the block stone content meets the following error requirements:

[0105]

[0106] Where e is the limit of relative error, which is taken as 5e-4 in this case.

[0107] According to the above steps, a two-dimensional random block stone that meets the requirements of gradation, shape, content, orientation, etc. can be generated within a sample size of 150mm×300mm. The present invention provides options of whether to use elliptical blocks and whether to rotate blocks, which can meet different usage requirements. Fig. 9 The figure shows the result of generating two-dimensional random blocks with a content of 40.00%, among which 9(a) is an "ellipse + non-rotation" block, 9(b) is an "ellipse + rotation" block, 9(c) is a "polygonal + non-rotation" block, and 9(d) is a "polygonal + rotation" block. The corresponding actual block contents are 40.003%, 40.003%, 40.012%, and 40.0029%, respectively. It can be seen that the actual generated block content is very close to the given block content of 40.00%.

[0108] S9: Post-process the coordinate information of all the stones and export and store them in txt format. Fig.10 As shown, Fig. 9(d) Taking the generated "polygon + rotation" block as an example, all the generated blocks are numbered (a total of 69), and the coordinate information corresponding to each block is exported and stored in txt text format. Then, it can be used to construct the geometric model of the soil-rock mixture sample in graphics drawing software such as AutoCAD, so as to carry out subsequent numerical simulation calculations in finite element software such as ABAQUS, finite difference software such as FLAC3D, etc.

[0109] <Example 2>

[0110] In the second embodiment, a two-dimensional random rock model of the slope is generated based on the technology of the present invention.

[0111] like Fig.11 As shown, the slope angle is 45°; Fig.12 The figure shows the cumulative distribution function curve of the particle size of the blocks generated in the two-dimensional slope; the specific gravity of the blocks used is G s_rock =3.00, soil specific gravity is G s_soil =1.40.

[0112] According to the simulation Fig.11 The actual size of the slope boundary shown in the figure is determined to be 130dm×200dm. A small amount of samples are taken from the local slope to be simulated, and a screening test is performed to obtain a particle grading curve. A series of particles with a content of 55% are generated within the rectangular boundary using the method of the present invention. Fig.12 The actual content of the block stone is 55.02%. Fig.13 Draw the boundary line of the slope within the rectangular boundary, remove the stones outside the boundary line (mark each stone with a serial number to facilitate the removal of unnecessary stone data and geometric information), and you can get the two-dimensional slope random stones. The specific process is as follows Fig.13 (b), 13(c), and 13(d). Because the location of the boulders is evenly distributed in the entire rectangular boundary area, it can be considered that the boulders content in the reselected slope area remains almost unchanged, still 55.02%. Finally, the location information of the boulders within the slope boundary line is stored.

[0113] Fig.14 The picture shows an exposed soil-rock mixed slope somewhere in Bafen Mountain, Jiangxia District, Wuhan City, Hubei Province (photographed on October 22, 2022). It can be seen that there are some exposed boulders on the slope surface. Fig.13 The result diagram shown in (c) can well reflect this natural form. On the one hand, for the convenience of numerical calculation (complex slope surface may lead to non-convergence of calculation), on the other hand, in order to ensure that the rock content within the set slope boundary meets the predetermined requirements, the rock part outside the slope boundary line can be removed. Of course, if it is not removed, the rock content will increase, but by Fig.13 (c) It can be seen that the increase is not large, so you can choose whether to remove the rocks that are exposed on the slope boundary line according to actual needs. If the rocks that exceed the boundary line (those that are partly inside the boundary line and partly outside the boundary line) are not removed, the actual situation of the exposed rocks on the slope can still be reflected.

[0114] Fig.11 The slope surface shown is not complicated. Fig.15 The complex two-dimensional slope shown, whether Fig.15 (a) shows a regular slope, or Fig.15 For the irregular slope shown in (b), the above method of the present invention can easily generate a two-dimensional random block rock model of the slope that meets the requirements of gradation, shape, content, orientation, etc.

[0115] <Example 3>

[0116] The third embodiment of the present invention provides a two-dimensional random block generation system in a soil-rock mixture that can automatically implement the above-mentioned method of the present invention. The system includes a parameter determination unit, a grading curve acquisition unit, a semi-major axis generation unit, a semi-minor axis generation unit, a center generation unit, a block generation unit, a content determination unit, a rotation unit, an error judgment unit, a drawing unit, a storage unit, an input display unit, and a control unit.

[0117] The parameter determination part determines the rectangular boundary surface and the rock block threshold according to the actual size of the soil-rock mixture to be simulated.

[0118] The gradation curve acquisition unit takes a small amount of samples from a local part of the soil-rock mixture to be simulated, performs a screening test, and obtains a particle gradation curve.

[0119] The semi-major axis generation unit obtains the distribution of the blocks in different particle size ranges according to the particle grading curve, and then obtains the cumulative distribution function of the block size. The Latin hypercube sampling method is used to generate a series of different semi-major axes, so that the frequency distribution of this series of semi-major axes is consistent with the probability distribution.

[0120] The semi-minor axis generating unit generates a series of different semi-minor axes corresponding to the semi-major axes from the probability distribution obeyed by the ratio of the minor axis to the major axis, so that the frequency distribution of the series of semi-minor axes is consistent with the probability distribution.

[0121] The center generating unit randomly generates the center coordinates of the ellipse within the rectangular boundary surface based on the generated series of semi-major axes and semi-segment axes, and ensures that any two ellipses do not overlap.

[0122] The stone block generation unit generates an arbitrary polygon inscribed in the ellipse as a simulated stone block.

[0123] The content determination unit calculates the current rock content based on the specific gravity of the soil and the rock.

[0124] The rotation part rotates the generated block stone to any angle through the coordinate rotation matrix.

[0125] The error judgment unit judges whether the current rock content up to the rectangular boundary surface meets the error ε requirement.

[0126] For the case where the soil-rock mixture to be simulated is a slope, the drawing unit, after obtaining the stone model filled in the rectangular boundary surface, draws the corresponding slope boundary line based on the actual shape of the slope to be simulated, removes the stones outside the slope boundary line from the stone model filled in the rectangular boundary surface, retains the stones within the slope boundary line, and outputs it as a random stone model of the slope.

[0127] The storage unit performs post-processing on the coordinate information of all the blocks in the model and stores the information as data.

[0128] The input display unit allows the operator to input operation instructions, and can display the input, output and intermediate processing information of each unit according to the operation instructions.

[0129] The control unit is connected to the parameter determination unit, the grading curve acquisition unit, the semi-major axis generation unit, the semi-minor axis generation unit, the center generation unit, the block generation unit, the content determination unit, the rotation unit, the error judgment unit, the drawing unit, the storage unit, and the input display unit, and controls their operation. The control unit controls the center generation unit, the block generation unit, the content determination unit, the rotation unit, and the error judgment unit to cyclically operate in the order described in the above method until the error judgment unit determines that the current block content of the rectangular boundary surface meets the error ε requirement, outputs the block model filled in the rectangular boundary surface, and controls the input display unit to display the block model.

[0130] The above embodiments are merely examples of the technical solutions of the present invention. The method and system for generating two-dimensional random blocks in a soil-rock mixture involved in the present invention are not limited to the contents described in the above embodiments, but are subject to the scope defined in the claims. Any modification, supplement or equivalent replacement made by a technician in the field of the present invention based on the embodiment is within the scope of protection required by the claims of the present invention.

Claims

1. A two-dimensional random block generation method in soil-rock mixture, without the need for image scanning during the processing. It is characterized in that The following steps are involved: Step 1, determining the rectangular boundary surface and the rock block threshold according to the actual size of the soil-rock mixture to be simulated; Step 2, a small amount of sampling is taken from a local part of the soil-rock mixture to be simulated, and a screening test is performed to obtain a particle grading curve. According to the particle grading curve, the distribution of the block stones in different particle size ranges is obtained, and then the cumulative distribution function of the block stone particle size is obtained. A series of different semi-major axes are generated by using the Latin hypercube sampling method, so that the frequency distribution of this series of semi-major axes is consistent with the probability distribution; Step 3, generating a series of different semi-minor axes corresponding to the semi-major axes from the probability distribution obeyed by the ratio of the minor axis to the major axis, so that the frequency distribution of the series of semi-minor axes is consistent with the probability distribution; Step 4: Based on steps 2 and 3, randomly generate the center coordinates of the ellipse within the rectangular boundary surface, and ensure that any two ellipses do not overlap; Step 5, generating an inscribed arbitrary polygon in the ellipse as a simulated stone block; Step 6, calculating the current rock content within the rectangular boundary surface based on the specific gravity of the soil and rock; Split the stone into multiple triangles with the center of the ellipse as the common vertex, calculate the area of ​​each triangle and sum them up to get the area of ​​a certain n-gonal stone, and then sum the areas of all the stones within the rectangular boundary surface: In the formula, S rock , S ij They represent the total area of ​​the blocks and the area of ​​the jth triangle of the ith block, respectively, and m represents the total number of blocks. Thus, the current content of the blocks can be obtained as: In the formula, F m ' ass 、F a ' rea Respectively represent the mass ratio and area ratio of the current stone block within the rectangular boundary surface; S 矩形边界面 Represents the area of ​​the rectangular boundary surface; G s_soil , G s_rock They represent the measured soil specific gravity and rock specific gravity of the sample respectively; Step 7, rotate the generated stone block to any angle using the coordinate rotation matrix; Step 8, repeat steps 4 to 7 until the current rock content within the rectangular boundary surface meets the error ε requirement:

2. The method for generating two-dimensional random blocks in a soil-rock mixture according to claim 1, characterized in that: in, In step 1, if the soil-rock mixture to be simulated is a slope, then after step 8, further execute: step 9, draw the slope boundary line, remove the blocks outside the slope boundary line, and keep the blocks within the slope boundary line.

3. The method for generating two-dimensional random blocks in a soil-rock mixture according to claim 2, characterized in that: in, The slope surface shape can be any complex shape.

4. The method for generating two-dimensional random blocks in a soil-rock mixture according to claim 1, characterized in that: in, In step 8, ε=5e-4.

5. Two-dimensional random block generation system in soil-rock mixture, It is characterized in that include: A parameter determination unit determines a rectangular boundary surface and a rock block threshold according to the actual size of the soil-rock mixture to be simulated; The gradation curve acquisition part takes a small amount of samples from a local part of the soil-rock mixture to be simulated, performs a screening test, and obtains a particle gradation curve; The semi-major axis generation part obtains the distribution of the block in different particle size ranges according to the particle grading curve, and then obtains the cumulative distribution function of the block particle size. The Latin hypercube sampling method is used to generate a series of different semi-major axes, so that the frequency distribution of this series of semi-major axes is consistent with the probability distribution. A semi-minor axis generating unit generates a series of different semi-minor axes corresponding to the semi-major axes from the probability distribution obeyed by the ratio of the minor axis to the major axis, so that the frequency distribution of the series of semi-minor axes is consistent with the probability distribution; The center generation part randomly generates the center coordinates of the ellipse within the rectangular boundary surface based on the generated series of semi-major axes and semi-segment axes, and ensures that any two ellipses do not overlap; A block stone generating part generates an inscribed arbitrary polygon in the ellipse as a simulated block stone; The content determination part calculates the current rock content based on the specific gravity of the soil and rock; splits the rock into multiple triangles with the center of the ellipse as the common vertex, calculates the area of ​​each triangle and sums them up to get the area of ​​a certain n-sided rock, and then sums the areas of all the rocks within the rectangular boundary surface: In the formula, S rock , S ij Respectively represent the total area of ​​the block, the area of ​​the jth triangle of the ith block, and m represents the total number of blocks; thus, the content of the block can be obtained as: In the formula, F m ' ass 、F a ' rea Respectively represent the mass ratio and area ratio of the current generation; S 矩形边界面 Represents the area of ​​the rectangular boundary surface; G s_soil , G s_rock They represent the measured soil specific gravity and rock specific gravity of the sample respectively; The rotation part rotates the generated stone blocks to any angle through the coordinate rotation matrix; The error judgment unit judges whether the current block content up to the rectangular boundary surface meets the error ε requirement: The control unit is connected to the parameter determination unit, the grading curve acquisition unit, the semi-major axis generation unit, the semi-minor axis generation unit, the center generation unit, the block generation unit, the content determination unit, the rotation unit, and the error judgment unit, and controls their operation; Among them, the control unit controls the center generation unit, the block stone generation unit, the content determination unit, the rotation unit, and the error judgment unit to run in a loop until the error judgment unit determines that the current block stone content of the rectangular boundary surface meets the error ε requirement, and outputs the block stone model filled in the rectangular boundary surface.

6. The system for generating two-dimensional random blocks in soil-rock mixture according to claim 5, It is characterized in that Also includes: The drawing unit is connected to the control unit for communication. When the soil-rock mixture to be simulated is a slope, after obtaining the block stone model filled in the rectangular boundary surface, the corresponding slope boundary line is drawn based on the actual shape of the slope to be simulated. The blocks outside the slope boundary line are removed from the block stone model filled in the rectangular boundary surface, and the blocks within the slope boundary line are retained, and the output is a random block stone model of the slope.

7. The two-dimensional random block generation system in soil-rock mixture according to claim 6, characterized in that: in, The slope surface shape can be any complex shape.

8. The system for generating two-dimensional random blocks in soil-rock mixture according to claim 6, It is characterized in that Also includes: The storage unit is connected to the control unit for post-processing the coordinate information of all the stones in the model and storing them as data information.

9. The system for generating two-dimensional random blocks in soil-rock mixture according to claim 5, It is characterized in that Also includes: The input display unit is connected to the control unit for communication, allowing the operator to input operating instructions and display them accordingly.

10. The system for generating two-dimensional random blocks in soil-rock mixture according to claim 5, Features: in, ε=5e-4.

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