CN107766623A - Random generation method for numerical model of asphalt mixture - Google Patents

Abstract

The present invention discloses a random generation method of an asphalt mixture numerical model, which randomly generates irregular polyhedral aggregates; and uses the irregular polyhedral aggregates to generate an asphalt mixture numerical model. The present invention reflects the random generation of a three-dimensional discrete element numerical model of an asphalt mixture that reflects irregular coarse aggregates, mineral gradation, asphalt mortar, and void distribution of the asphalt mixture, while fully reflecting the angular characteristics of the aggregates and avoiding the problem of parallel or overlapping cutting surfaces.

Description

A Random Generation Method of Numerical Model of Asphalt Mixture

technical field

The invention relates to the field of asphalt mixture numerical simulation modeling, in particular to a method for randomly generating an asphalt mixture numerical model.

Background technique

The internal structure of asphalt mixture is very complex. It is a multiphase composite material composed of aggregate, asphalt and voids. To carry out numerical simulation, the first problem to be solved is how to establish a numerical model that can reflect the internal characteristics of asphalt mixture. At present, the methods for asphalt mixture modeling mainly include:

1. The traditional method of obtaining the numerical model of asphalt mixture is usually to take photos of the surface of the mixture or the section of the specimen after cutting with a digital camera, or use industrial CT to perform tomographic scanning on the asphalt mixture specimen, and then use the relevant digital image Processing technology, such as image enhancement technology, image segmentation technology, image edge detection technology, etc., obtains the binary image of the mixture specimen, and performs digital reconstruction to obtain the numerical model of the mixture specimen. Although this method can obtain a digital model with a high degree of matching with the real test piece, it has the following disadvantages: high test requirements, high cost, and inability to achieve simulation requirements in some cases.

2. Direct modeling method

The disadvantage of this method is that the mixture is regarded as a homogeneous body, which is inconsistent with the actual situation.

3. Random reconstruction generation method,

Although this method has achieved great results, the current algorithm has the following defects, that is, in the aggregate generation algorithm, there will be problems such as parallel cutting planes or overlapping.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for randomly generating an asphalt mixture numerical model to reflect the irregular shape of the asphalt mixture coarse aggregate, ore gradation, asphalt mortar, and asphalt with void distribution in view of the deficiencies in the prior art The random generation of the three-dimensional discrete element numerical model of the mixture fully reflects the angular characteristics of the aggregate and avoids the problem of parallel or overlapping cutting surfaces.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for randomly generating an asphalt mixture numerical model, comprising the following steps:

1) Randomly generate irregular polyhedral aggregates;

2) Using the irregular polyhedral aggregates to generate an asphalt mixture numerical model.

The specific implementation process of step 1) includes:

A) Filling regularly arranged small particle size discrete units in the polyhedron;

B) Generate multiple random planes to randomly cut the cube to obtain an irregular polyhedron region;

C) judging the relative position of the centroid position of the discrete unit with small particle size and the polyhedron region obtained in step B), and taking the discrete unit with small particle size inside the polyhedron region as the aggregate part of the irregular polyhedron.

In step A), the side length of the cube is equal to the particle size of the polyhedron aggregate; the mathematical equation of the cube is as follows:

Among them, (x ₀ , y ₀ , z ₀ ) are the coordinates of the centroid O of the cube; 2R is the side length of the square; (x, y, z) are the coordinates of any point within the cube.

In step B), the number of said random planes is 8; the specific implementation process of step B) includes the following steps:

a) Randomly generate a normal vector (n _j1 , n _j2 , n _j3 ) of each quadrant cutting plane, and the value of j is 1 to 8; the calculation formula of n _j1 , n _j2 , n _j3 is as follows:

t ₁ =cos(α)

t ₂ =sin(α)

t ₃ =cos(β);

n _j1 =t ₁ /tt

n _j2 =t ₂ /tt

n _j3 =t ₃ /tt

Among them, urand is a random function with a value range of (0, 1); int is a rounding function; α is the angle between a line in the horizontal plane and the x-axis; β is the angle between a line in the horizontal plane and the z-axis angle; t ₁ , t ₂ , t ₃ are the cosines of the angles between a line in space and the x, y, z coordinate axes;

b) Solve the distance d from the centroid of the cube to the cutting plane: d=R×q; wherein, q is the cutting control coefficient;

c) According to the distance d and the normal vector (n _j1 , n _j2 , n _j3 ), the coordinates of the intersection point M _c (x _c , y _c , z _c ) of the centroid O of the cube and the vertical line of the cutting surface are obtained as follows:

x _c ＝x ₀ +d×n _j1

y _c =y ₀ +d×n _j2 ;

z _c =z ₀ +d×n _j3

d) Use the following formula to determine the random plane P _j :

P _j =x×n _j1 +y×n _j2 +z×n _j3 -(x _c ×n _j1 +y _c ×n _j2 +z _c ×n _j3 )=0;

e) cutting the cube with a random plane to obtain an irregular polyhedron region, and the mathematical equation of the irregular polyhedron region is as follows:

x-(x ₀ -R)≥0

x-(x ₀ +R)≤0

y-(y ₀ -R)≥0

y-(y ₀ +R)≤0.

z-(z ₀ -R)≥0

z-(z ₀ +R)≤0

P _j ≤ 0

The specific implementation process of step 2) includes:

1) determine the number of each file aggregate unit of the mixture;

II) According to the number of aggregate units in each file, the graded parent particles are put in;

III) Read and save the collection information of the graded parent particles;

IV) Delete the graded parent particles to generate regularly arranged small particles;

V) generate an irregular aggregate model, and carry out a gradation test;

VI) Create voids in the irregular aggregate model to obtain an asphalt mixture numerical model. In step 1), first calculate the percentage of the total volume of the asphalt mixture specimen that the i-th grade aggregate accounts for according to the following formula:

Among them, J _Di is the percentage of the i-th grade aggregate in the total volume of the asphalt mixture specimen; P _Di-1 and P _Di are the passage rates of the i-1 grade and the i-th grade aggregate respectively; VV is the porosity ; a is the ratio of asphalt; ρ _c is the density of coarse and fine aggregates; ρ _l is the density of asphalt.

The percentage of each grade of aggregate in the total volume of the specimen is calculated through the above formula, then the total volume of each grade of aggregate can be known if the volume of the specimen is known, and then the total volume of each grade of aggregate is divided by the volume of a single aggregate particle The number of aggregate particles in each gear can be obtained by volume.

Assume that the volume of the cylinder specimen is

V=πd ² h/4;

Among them, d is the diameter of the bottom circle of the cylinder; h is the height of the cylinder; then the number of aggregates in each file is:

Among them, r _i is the average radius of aggregate particles in the i-th file, here r _i = (D _i-1 + D _i )/4, where D _i-1 and D _i are the i-1th file and the i-th file respectively mesh size.

The specific implementation process of step II) includes: according to the number of aggregate units in each file, put the aggregate particles into the cylinder model, scan each file of aggregate particles, and calculate the volume fraction of each file of aggregate particles, if If the volume fraction is consistent with the actual volume fraction, then the delivery is correct.

In step IV), after deleting the gradation parent particles, arrange the aggregate particles with a particle size smaller than the minimum particle size of the coarse aggregate particles according to the following rules: ensure that all aggregate particles are neatly arranged in the horizontal direction and the vertical direction , and each particle in the middle position is adjacent to one particle in each of the six directions of up, down, left, right, front and back.

In step V), when the percentage of each level of aggregate particles in the total particles of the entire cylinder model is within the percentage threshold, the grading test is successful; otherwise, regenerate the level of aggregate until the level of aggregate particles accounts for the entire If the percentage of the total particles of the cylinder model is within the percentage threshold, then the next grade of aggregate is generated; finally an irregular aggregate model is obtained.

The specific implementation process of step VI) is: generate a random number within the maximum particle range of the irregular aggregate model, and judge whether the particle address with the random number as the serial number is empty, if not, then judge that the random number is Whether the particle of the serial number is asphalt mortar, if so, delete the particle until n_del particles are deleted, and the numerical model of asphalt mixture is obtained.

Compared with the prior art, the beneficial effects of the present invention are: the present invention reflects the randomness of the asphalt mixture three-dimensional discrete element numerical model of the asphalt mixture irregular shape coarse aggregate, ore gradation, asphalt mortar and void distribution. Generation, while fully reflecting the angular characteristics of the aggregate, it avoids the problem of parallel or overlapping cutting surfaces.

Description of drawings

Fig. 1 is the throwing figure of aggregate of the present invention;

Fig. 2 is a regular arrangement particle diagram of the present invention;

Fig. 3 is irregular aggregate sample figure (no gap) of the present invention;

Fig. 4 is a distribution diagram of voids of the present invention;

Figure 5(A) Irregular aggregate model diagram; Figure 5(B) Vertical section view of irregular aggregate module; Figure 5(C) Horizontal section view of irregular aggregate model.

Detailed ways

The concrete realization process of the present invention is as follows:

1) Random generation of irregular polyhedral aggregates;

1.1) Filling regularly arranged small particle size discrete units;

1.2) Generate eight random planes to randomly cut the cube;

1.3) Judging the relative position (the centroid position of the small particle size discrete unit (actually the relative position of the spherical center coordinates (x, y, z)) and the irregular polyhedron region);

2) Generation of asphalt mixture numerical model;

Asphalt mixture is generally considered to be composed of aggregate, asphalt mortar, and voids. Step 1) proposes a single aggregate generation method, and step 2) generates asphalt mixture on the basis of 1).

2.1) Determination of the number of gradation units;

2.2) Grading parent particle delivery;

2.3) Read and save the geometric information of the gradation matrix particles;

2.4) Deleting the parent particles to generate regularly arranged small particles;

2.5) Load the irregular aggregate generation program; generate irregular aggregate, and carry out gradation inspection;

2.6) Generation of voids.

In step 1.1): Write a program so that particles with smaller particle sizes are filled in a certain order in the specified cube area, and set the side length of the area to be equal to the particle size of the aggregate. The mathematical equation of the cube is as formula (1):

In the formula, x ₀ , y ₀ , z ₀ ——the O coordinate of the centroid of the cube; 2R——the side length of the cube, that is, the particle size of the aggregate; (x, y, z) is the coordinate of any point in space.

In step 1.2): the generation process of the random plane is as follows:

a) Generate a normal vector (n _j1 , n _j2 , n _j3 ) of each quadrant cutting plane, the normal vector is randomly generated, where j is equal to 1~8, n _j1 , n _j2 , n _j3 are calculated by formula (2) .

t ₁ =cos(α)

t ₂ =sin(α)

t ₃ =cos(β) (2)

n _j1 =t ₁ /tt

n _j2 =t ₂ /tt

n _j3 =t ₃ /tt

In the formula, urand—the random function inside the computer, the range is (0, 1), int—the rounding function inside the computer.

Reply to Note 5: α——the angle between the xoy plane (which can be considered as the horizontal plane) and the x axis, starting from the x axis counterclockwise, similar to the azimuth angle;

β——the angle with the z axis, similar to the inclination angle.

t ₁ , t ₂ , and t ₃ are the cosines of the angles between a line in space and the x, y, and z coordinate axes.

In fact, the above-mentioned space straight line is: first determine the random angle α on the xoy plane, and then determine the random angle β in the vertical direction.

b) The distance d from the centroid of the cube to the cutting plane is shown in formula (3).

d=R×q (3)

In the formula: q is the cutting control coefficient, which is between 0 and 1.0.

c) According to the previous distance d and the normal vector (n _j1 , n _j2 , n _j3 ), the intersection point M _c (x _c , y _c , z _c ) of the perpendicular line between the centroid O of the cube and the cutting surface can be obtained The coordinates are as follows:

x _c ＝x ₀ +d×n _j1

y _c =y ₀ +d×n _j2 (4)

z _c =z ₀ +d×n _j3

Then the random plane equation is:

P _j ＝x×n _j1 +y×n _j2 +z×n _j3 -(x _c ×n _j1 +y _c ×n _j2 +z _c ×n _j3 )＝0 (5)

d) According to the randomly generated cutting surface, use it to cut the cube to obtain an irregular polyhedron area. The mathematical equation of the irregular polyhedron area is as formula (6):

x-(x ₀ -R)≥0

x-(x ₀ +R)≤0

y-(y ₀ -R)≥0

y-(y ₀ +R)≤0 (6)

z-(z ₀ -R)≥0

z-(z ₀ +R)≤0

P _j ≤ 0

In step 2.1): when calculating the number of particles required by the model, since the passing rate of the gradation in the specification uses the amount calculated by the quality representation, in order to characterize the gradation characteristics of the mixture in the model, we assume that the aggregate If the densities are all equal, the gradation becomes a quantity represented by mass and converted into a quantity represented by volume, and then calculate the number of graded ball units according to the volume fraction, that is, calculate the proportion of the specimen occupied by a certain grade of aggregate according to the volume fraction. Volume, and then divided by the average volume of the ball to get the number of aggregate particles in this file, where the radius of the ball is half of the average value of the upper and lower limits of the file. Therefore, the key to reflect the gradation is to calculate the volume fraction of each grade of aggregate, which is now deduced as follows:

Assuming that the density of coarse and fine aggregates is known to be ρ _c , the density of asphalt is ρ _l , the asphalt ratio is a, the design porosity is VV, and the volume of the cylindrical specimen is V=πd ² h/4, where d is the diameter, h for the height. And set the volume of asphalt as V _l , the volume of coarse aggregate as V _c , and the volume of fine aggregate as V _x . The pass rate of aggregate is shown in Table 1. Calculate the volume percentage of each grade of aggregate and asphalt mortar in the asphalt mixture specimen .

Table 1 The passing rate of aggregates in each file

According to the calculation formula of oil-stone ratio, namely:

m _l , m _c , m _x are respectively: the quality of asphalt, the quality of coarse aggregate, and the quality of fine aggregate. The so-called asphalt ratio is the ratio of asphalt mass to aggregate mass.

The content of asphalt in the numerical test piece can be obtained as follows:

According to the volume composition of the whole specimen, there are:

V(1-VV)＝V _l +V _c +V _x (9)

Put formula (8) into formula (9), we can get:

According to the grading pass rate table, it can be obtained:

And because the densities are equal, then:

Substituting formula (12) into formula (10), we have:

Combined with the gradation pass rate table, the volume fraction formula of each grade of aggregate accounted for numerical test piece can be obtained as follows:

Therefore, from equations (10) and (14), we get:

In addition, the density parameter ρ _s of asphalt mortar can also be deduced from formula (7) and formula (9):

Then put formula (8) into formula (16), then:

The AC-13 mixture gradation is shown in Table 2. The asphalt density is 1.03, the aggregate density is 2.7, the asphalt ratio is 5%, and the porosity is 4%. The cylindrical test piece has a diameter of 100 mm and a height of 100 mm. According to the above formula, the number of particles in each grade is calculated as shown in Table 3.

In asphalt mixture, the aggregates of different particle sizes are divided into different grades, and the proportion of each grade to the total mass is different, thereby forming a gradation. Here, the number of aggregate particles in each grade is determined. It is equivalent to determining their ratio, thus obtaining the number of gradation units.

Table 2 AC-13 mixture gradation

Table 3 Calculation of the number of AC-13 asphalt mixture

In step 2.2): According to the calculated number of aggregates, put them into the model, as shown in Figure 1, then scan each grade of particles and calculate the corresponding volume fraction, and find that it is consistent with the actual value, indicating that the placement is correct. In step 2.3): write a program to scan the above-mentioned graded spherical unit (that is, scan all the particle units generated above), and then extract the information of each aggregate particle - coordinates (x, y, z) and radius r, etc. as the generated Geometry parameters of the polygonal aggregate.

Step 2.4): delete the original particles, and fill the area with particles of smaller particle size according to a certain order (the regular arrangement is horizontal, flat and vertical, and one particle is arranged adjacent to 6 particles in the front, bottom, left, right, front and back), as shown in Figure 2 shown.

In step 2.5): load the irregular aggregate generation program, and perform gradation check. The principle of gradation check is to calculate the percentage of all small ball particles of each aggregate in the total model particles. When the particles If the percentage is within the target percentage range (such as ±5%, ±10%, depending on the required accuracy), it meets the requirements. Otherwise, regenerate this file of aggregates by adjusting the cutting control coefficient, and then generate the next file of aggregates until the requirements are met. The resulting irregular aggregate model is shown in Figure 3.

In step 2.6): In order to create certain voids in the above model, a random deletion method is used to randomly delete some particles of the asphalt mortar to represent the voids of the mixture. Assuming that the porosity is VV, the number n_del of asphalt mortar particles needs to be deleted and calculated by formula (18).

n_del=int(VV*n_total) (18)

In the formula: n_total is the total number of small particles in the model.

By writing a program, each time a random number is generated within the maximum particle range of the model, and it is judged whether the particle address with this number as the serial number is not an empty address and whether the particle is asphalt mortar, and if so, delete the particle until n_del number is deleted After the particles stop, the void distribution diagram is shown in Figure 4, and the cylindrical numerical model of asphalt mixture is shown in Figure 5(A), Figure 5(B) and Figure 5(C).

For example, if the total number of particles in the model is 48040 and the porosity is 4%, then the number n_del of particles to be deleted is 1921.

Claims (10)

1. A random generation method of asphalt mixture numerical model, is characterized in that, comprises the following steps: 1) Randomly generate irregular polyhedral aggregates; 2) Using the irregular polyhedral aggregates to generate an asphalt mixture numerical model. 2. the asphalt mixture numerical model random generation method according to claim 1, is characterized in that, the concrete realization process of step 1) comprises: A) Filling regularly arranged small particle size discrete units in the polyhedron; B) Generate multiple random planes to randomly cut the cube to obtain an irregular polyhedron region; C) judging the relative position of the centroid position of the discrete unit with small particle size and the polyhedron region obtained in step B), and taking the discrete unit with small particle size inside the polyhedron region as the aggregate part of the irregular polyhedron. 3. the asphalt mixture numerical model random generation method according to claim 2, is characterized in that, in step A), described cube side length is equal to described polyhedron aggregate particle diameter; The mathematical equation of described cube is as follows: <mrow><mtable><mtr><mtd><mrow><mi>x</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>x</mi><mn>0</mn></msub><mo>-</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;GreaterEqual;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>x</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>x</mi><mn>0</mn></msub><mo>+</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;le;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>y</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>y</mi><mn>0</mn></msub><mo>-</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;GreaterEqual;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>y</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>y</mi><mn>0</mn></msub><mo>+</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;le;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>z</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>z</mi><mn>0</mn></msub><mo>-</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;GreaterEqual;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>z</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>z</mi><mn>0</mn></msub><mo>+</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;le;</mo><mn>0</mn></mrow></mtd></mtr></mtable><mo>;</mo></mrow> Among them, (x ₀ , y ₀ , z ₀ ) are the coordinates of the centroid O of the cube; 2R is the side length of the square; (x, y, z) are the coordinates of any point within the cube. 4. the asphalt mixture numerical model random generation method according to claim 3, is characterized in that, in step B), described random plane number is 8; The concrete realization process of step B) comprises the following steps: a) Randomly generate a normal vector (n _j1 , n _j2 , n _j3 ) of each quadrant cutting plane, and the value of j is 1 to 8; the calculation formula of n _j1 , n _j2 , n _j3 is as follows: <mrow><mtable><mtr><mtd><mrow><mi>&amp;alpha;</mi><mo>=</mo><mi>u</mi><mi>r</mi><mi>a</mi><mi>n</mi><mi>d</mi><mo>&amp;times;</mo><mfrac><mi>&amp;pi;</mi><mn>2.0</mn></mfrac><mo>+</mo><mrow><mo>(</mo><mi>j</mi><mo>-</mo><mn>1.0</mn><mo>)</mo></mrow><mo>&amp;times;</mo><mfrac><mi>&amp;pi;</mi><mn>2.0</mn></mfrac></mrow></mtd></mtr><mtr><mtd><mrow><mi>&amp;beta;</mi><mo>=</mo><mi>u</mi><mi>r</mi><mi>a</mi><mi>n</mi><mi>d</mi><mo>&amp;times;</mo><mfrac><mi>&amp;pi;</mi><mn>2.0</mn></mfrac><mo>+</mo><mrow><mo>(</mo><mi>int</mi><mo>(</mo><mrow><mrow><mo>(</mo><mrow><mi>j</mi><mo>-</mo><mn>1.0</mn></mrow><mo>)</mo></mrow><mo>/</mo><mn>4.0</mn></mrow><mo>)</mo><mo>)</mo></mrow><mo>&amp;times;</mo><mfrac><mi>&amp;pi;</mi><mn>2.0</mn></mfrac></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>t</mi><mn>1</mn></msub><mo>=</mo><mi>cos</mi><mrow><mo>(</mo><mi>&amp;alpha;</mi><mo>)</mo></mrow></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>t</mi><mn>2</mn></msub><mo>=</mo><mi>sin</mi><mrow><mo>(</mo><mi>&amp;alpha;</mi><mo>)</mo></mrow></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>t</mi><mn>3</mn></msub><mo>=</mo><mi>cos</mi><mrow><mo>(</mo><mi>&amp;beta;</mi><mo>)</mo></mrow></mrow></mtd></mtr><mtr><mtd><mrow><mi>t</mi><mi>t</mi><mo>=</mo><msqrt><mrow><msubsup><mi>t</mi><mn>1</mn><mn>2</mn></msubsup><mo>+</mo><msubsup><mi>t</mi><mn>2</mn><mn>2</mn></msubsup><mo>+</mo><msubsup><mi>t</mi><mn>3</mn><mn>2</mn></msubsup></mrow></msqrt></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>n</mi><mrow><mi>j</mi><mn>1</mn></mrow></msub><mo>=</mo><msub><mi>t</mi><mn>1</mn></msub><mo>/</mo><mi>t</mi><mi>t</mi></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>n</mi><mrow><mi>j</mi><mn>2</mn></mrow></msub><mo>=</mo><msub><mi>t</mi><mn>2</mn></msub><mo>//</mo><mi>t</mi><mi>t</mi></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>n</mi><mrow><mi>j</mi><mn>3</mn></mrow></msub><mo>=</mo><msub><mi>t</mi><mn>3</mn></msub><mo>/</mo><mi>t</mi><mi>t</mi></mrow></mtd></mtr></mtable><mo>;</mo></mrow> Among them, urand is a random function with a value range of (0, 1); int is a rounding function; α is the angle between a line in the horizontal plane and the x-axis; β is the angle between a line in the horizontal plane and the z-axis angle; t ₁ , t ₂ , t ₃ are the cosines of the angles between a line in space and the x, y, z coordinate axes; b) Solve the distance d from the centroid of the cube to the cutting plane: d=R×q; wherein, q is the cutting control coefficient; c) According to the distance d and the normal vector (n _j1 , n _j2 , n _j3 ), the coordinates of the intersection point M _c (x _c , y _c , z _c ) of the centroid O of the cube and the vertical line of the cutting surface are obtained as follows: <mrow><mtable><mtr><mtd><mrow><msub><mi>x</mi><mi>c</mi></msub><mo>=</mo><msub><mi>x</mi><mn>0</mn></msub><mo>+</mo><mi>d</mi><mo>&amp;times;</mo><msub><mi>n</mi><mrow><mi>j</mi><mn>1</mn></mrow></msub></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>y</mi><mi>c</mi></msub><mo>=</mo><msub><mi>y</mi><mn>0</mn></msub><mo>+</mo><mi>d</mi><mo>&amp;times;</mo><msub><mi>n</mi><mrow><mi>j</mi><mn>2</mn></mrow></msub></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>z</mi><mi>c</mi></msub><mo>=</mo><msub><mi>z</mi><mn>0</mn></msub><mo>+</mo><mi>d</mi><mo>&amp;times;</mo><msub><mi>n</mi><mrow><mi>j</mi><mn>3</mn></mrow></msub></mrow></mtd></mtr></mtable><mo>;</mo></mrow> d) Use the following formula to determine the random plane P _j : P _j =x×n _j1 +y×n _j2 +z×n _j3 -(x _c ×n _j1 +y _c ×n _j2 +z _c ×n _j3 )=0; e) cutting the cube with a random plane to obtain an irregular polyhedron region, and the mathematical equation of the irregular polyhedron region is as follows: <mrow><mtable><mtr><mtd><mrow><mi>x</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>x</mi><mn>0</mn></msub><mo>-</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;GreaterEqual;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>x</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>x</mi><mn>0</mn></msub><mo>+</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;le;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>y</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>y</mi><mn>0</mn></msub><mo>-</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;GreaterEqual;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>y</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>y</mi><mn>0</mn></msub><mo>+</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;le;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>z</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>z</mi><mn>0</mn></msub><mo>-</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;GreaterEqual;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>z</mi><mo>-</mo><mrow><mo>(</mo><msub><mi>z</mi><mn>0</mn></msub><mo>+</mo><mi>R</mi><mo>)</mo></mrow><mo>&amp;le;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>P</mi><mi>j</mi></msub><mo>&amp;le;</mo><mn>0</mn></mrow></mtd></mtr></mtable><mo>.</mo></mrow> 5. the asphalt mixture numerical model random generation method according to claim 1, is characterized in that, the concrete realization process of step 2) comprises: 1) determine the number of each file aggregate unit of the mixture; II) According to the number of aggregate units in each file, the graded parent particles are put in; III) Read and save the collection information of the graded parent particles; IV) Delete the graded parent particles to generate regularly arranged small particles; V) generate an irregular aggregate model, and carry out a gradation test; VI) Create voids in the irregular aggregate model to obtain an asphalt mixture numerical model. 6. the asphalt mixture numerical model random generation method according to claim 5, is characterized in that, in step 1), adopts following formula to calculate every grade of aggregate particle number, according to every grade of aggregate particle number, obtains every grade The number of file collection units: <mrow><msub><mi>n</mi><mi>i</mi></msub><mo>=</mo><mrow><mo>(</mo><mi>V</mi><mo>&amp;times;</mo><msub><mi>J</mi><mrow><mi>D</mi><mi>i</mi></mrow></mi>msub><mo>)</mo></mrow><mo>/</mo><mrow><mo>(</mo><mfrac><mn>4</mn><mn>3</mn></mfrac><msubsup><mi>&amp;pi;r</mi><mi>i</mi><mn>3</mn></msubsup><mo>)</mo></mrow><mo>;</mo></mrow> Wherein, V=πd ² h/4 is the volume of the cylinder model, and d is the diameter of the bottom circle of the cylinder model; h is the height of the cylinder model; is the percentage of the i-th grade aggregate in the total volume of the asphalt mixture; P _Di-1 and P _Di are the passing rates of the i-1 grade and the i-th grade aggregate respectively; VV is the porosity; a is the asphalt ratio; _{ρ c} is the density of coarse and fine _{aggregate ; ρ l} is the density of _asphalt ; mesh size. 7. the asphalt mixture numerical model random generation method according to claim 5, is characterized in that, the specific realization process of step II) comprises: according to each file aggregate unit number, the aggregate particles are put into the cylinder model , scan each level of aggregate particles, and calculate the volume fraction of each level of aggregate particles, if the volume fraction is consistent with the actual volume fraction, then the delivery is correct. 8. the asphalt mixture numerical model random generation method according to claim 7, is characterized in that, step IV) in, after deleting described gradation parent particle, the aggregate with particle diameter less than the minimum particle diameter of coarse aggregate particle The particles are arranged according to the following rules: ensure that all aggregate particles are neatly arranged in the horizontal and vertical directions, and each particle in the middle position is adjacent to one particle in each of the six directions of up, down, left, right, front and back arrangement. 9. The method for randomly generating an asphalt mixture numerical model according to claim 8, characterized in that, in step V), when the percentage of each file of aggregate particles accounting for the total particles of the entire cylinder model is within the percentage threshold, then The grading test is successful; otherwise, regenerate the aggregate until the percentage of the aggregate particles in the entire cylinder model is within the percentage threshold, and then generate the next aggregate; finally an irregular aggregate model is obtained. 10. the asphalt mixture numerical model random generation method according to claim 5, is characterized in that, the concrete realization process of step VI) is: produce a random number within the maximum particle scope of described irregular aggregate model, judge with Whether the particle address with the random number as the serial number is empty, if not, then judge whether the particle with the random number as the serial number is asphalt mortar, if so, delete the particle until n_del particles are deleted, and stop to get the value of the asphalt mixture model; where: n_del=int(VV*n_total); In the formula: n_total is the total number of particles in the irregular aggregate model; VV is the porosity.