A method for improving the construction efficiency of the mesoscopic model of soil-rock mixture
By quickly forming invading blocks of convex polygons in the earth-rock mixture, the calculation time-consuming problem in the prior art is solved, and the efficient construction of the meticulous model of the earth-rock mixture is achieved.
Patent Information
- Application Number
- CN202311595511.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-27
- Publication Date
- 2025-05-30
- Estimated Expiration
- 2043-11-27
AI Technical Summary
In the existing method of mesoscopic model construction of soil and rock mixtures, the process of calculating the invading blocks of convex polygons and convex polygons in the soil and rock mixtures takes a long time and has low formation efficiency, which affects the overall modeling efficiency.
By quickly forming intruding blocks of the block convex polygon to be dropped and the placed block convex polygons, the sequential vertex sets of intruding blocks are directly formed, without adjusting the order of the vertex sets, and the formation of each vertex does not require traversing all sides of the convex polygon B or convex polygon A.
The invading blocks of convex polygons and convex polygons are quickly constructed, thereby significantly improving the construction efficiency of the mesoscopic model of earth and rock mixtures.
Smart Images
Figure CN118036106B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of numerical simulation of soil-rock mixtures, and particularly to a method for improving the construction efficiency of the mesoscopic model of soil-rock mixtures. Background Art
[0002] Currently, constructing the mesoscopic model of soil-rock mixtures by borrowing a computer is a relatively common technical means. In the literature "Establishment of a two-dimensional mesoscopic structure model of soil-rock mixtures and numerical manifold method simulation" in the 8th issue of the 38th volume of "Rock and Soil Mechanics" in August 2017, a method for constructing the mesoscopic model of soil-rock mixtures is involved. In this method, the construction of the mesoscopic model of soil-rock mixtures is divided into two steps: the generation and placement of random boulders. In the modeling process, randomly generated convex polygons are used to replace the boulders in the soil-rock mixture. During the placement process of the random convex polygons, the convex polygon to be placed and the already placed convex polygons cannot overlap. To facilitate the determination of whether two convex polygons overlap and the determination of the position of the convex polygon to be placed, the concept of an intruding block (i.e., the Entrance Block in this literature) is introduced. Define the already placed convex polygon as B and the convex polygon to be placed as A. Assume that a0 is any selected reference point on A. After a series of calculations, the area represented by the intruding block formed by the two can be obtained (such as the area enclosed by the dotted line in the literature Figure 2 ). The intruding block is related to the shapes, sizes of the convex polygon A, the convex polygon B, and the position of the reference point a0. If a0 is outside the area of the intruding block or on the boundary of the area, the convex polygon A and the convex polygon B do not overlap. If a0 is inside the area of the intruding block, the convex polygon A and the convex polygon B overlap.
[0003] In this modeling method, every time a new random convex polygon is placed, it is necessary to calculate the intruding block of this random convex polygon and each of the already placed convex polygons. The overall calculation amount is large and the calculation time is serious. The calculation amount of the intruding block between convex polygons accounts for a considerable part of the overall modeling calculation amount. In the existing method for forming the intruding block (i.e., the 2.2.2 EAB algorithm in the literature), the formation of each side of the intruding block requires traversing all the sides of the convex polygon B or the convex polygon A, and it is necessary to first form the edge set of the intruding block and then adjust the order of the edges in the edge set to form the intruding block, resulting in low formation efficiency. Therefore, a fast formation method for the intruding block between convex polygons can improve the construction efficiency of the mesoscopic model of soil-rock mixtures. Summary of the Invention
[0004] The object of the present invention is to propose a method for improving the construction efficiency of the mesoscopic model of soil-rock mixtures, which can quickly construct the intruding block between convex polygons, thereby improving the construction efficiency of the mesoscopic model of soil-rock mixtures.
[0005] To achieve the above object, the present invention adopts the following technical solutions:
[0006] A method for improving the construction efficiency of the mesoscopic model of soil-rock mixture. In this method, the construction of the mesoscopic model of soil-rock mixture is divided into two steps: the generation and placement of random boulders. During the modeling process, randomly generated convex polygons are used to replace the boulders in the soil-rock mixture. During the placement process of the random convex polygons, the convex polygon to be placed should not overlap with the already placed convex polygons. To facilitate the determination of whether two convex polygons overlap and the determination of the position of the convex polygon to be placed, the concept of an intruding block is introduced. Define the already placed convex polygon as B and the convex polygon to be placed as A. Assume that a0 is an arbitrarily selected reference point on A. Through a series of calculations, the area represented by the intruding block formed by the two can be obtained. The intruding block is related to the shapes, sizes of the convex polygon A and the convex polygon B, and the position of the reference point a0. If a0 is outside the area of the intruding block or on the boundary of the area, then the convex polygon A and the convex polygon B do not overlap. If a0 is inside the area of the intruding block, then the convex polygon A and the convex polygon B overlap. Quickly forming the intruding block of the convex polygon of the boulder to be placed and the already placed convex polygon of the boulder will improve the construction efficiency of the mesoscopic model of the soil-rock mixture. The convex polygon A and the convex polygon B are in the same plane;
[0007] Assume that the convex polygon A has m sides and the convex polygon B has n sides. Denote the x and y coordinates of the k-th (1 ≤ k ≤ m) vertex of the convex polygon A as The x and y coordinates of the l-th (1 ≤ l ≤ n) vertex of the convex polygon B are And arbitrarily select a point in the convex polygon A as the reference point, and its x and y coordinates are
[0008] It includes the following steps:
[0009] S1. In sequence according to the counterclockwise order of the sides, calculate the set of inner normal vectors of the sides forming the convex polygon A according to the coordinates of the two vertices of each side. The inner normal vector of the k-th (1 ≤ k ≤ m - 1) side of the convex polygon A is The inner normal vector of the m-th side of the convex polygon A is
[0010] S2. In sequence according to the counterclockwise order of the sides, calculate the set of outer normal vectors of the sides forming the convex polygon B according to the coordinates of the two vertices of each side. The outer normal vector of the l-th (1 ≤ l ≤ n - 1) side of the convex polygon B is The outer normal vector of the n-th side of the convex polygon B is
[0011] S3. Among the set of sequential normal vectors of the sides of convex polygon A, find the first vector after the last external normal vector of convex polygon B. After that.
[0012] S4. Add vertices to the set of sequential vertices of the intruding block one by one, and the polygon formed by connecting the vertices linearly is the intruding block.
[0013] Preferably, step S3 further includes the following steps:
[0014] S31. Calculate Let k = 0;
[0015] S32. Let result_last = result, and let k = k + 1, then calculate
[0016] S33. Repeat step S32 until result_last ≤ 0 and result > 0, record this k value, and this Is the first vector after the last external normal vector of convex polygon B in the set of sequential normal vectors of the sides of convex polygon A. After that.
[0017] Preferably, step S4 further includes the following steps:
[0018] S41. According to the k value obtained in step S33, obtain the first vertex of the intruding block, and its x and y coordinates are: Let k_flag = k, and let l = 1;
[0019] S42. Calculate If result > 0, then let l = l + 1; if result = 0, then let k = k + 1 and l = l + 1; if result < 0, then let k = k + 1;
[0020] S43. If l > n at this time, jump to step S46;
[0021] If l ≤ n at this time, then perform step S44;
[0022] S44. If k > m, then let k = 1, and add a new vertex to the set of sequential vertices of the intruding block, and its x and y coordinates are respectively
[0023] If k ≤ m, then add a new vertex to the set of sequential vertices of the intruding block, and its x and y coordinates are respectively
[0024] S45. Repeat the execution of S42 - S44 until l = n and k = k_flag;
[0025] S46. Using the coordinates obtained in step S41 as the first vertex of the intruded block, sequentially connect the vertices of the intruded block obtained in S42 - S45, which is the intruded block.
[0026] The beneficial effects of the present invention are as follows:
[0027] 1. This method for quickly forming the intruded block directly forms the sequential vertex set of the intruded block without adjusting the order of the vertices in the vertex set, and the formation of each vertex does not require traversing all the edges of convex polygon B or convex polygon A. Therefore, this method can quickly construct the intruded block of convex polygon and convex polygon, thereby improving the construction efficiency of the meso - scale model of soil - rock mixture. Description of the Drawings
[0028] Figure 1 It is the flowchart of S42 - S44 in the present invention;
[0029] Figure 2 It is the schematic diagram of convex polygon A and convex polygon B in the coordinate system in the second embodiment of the present invention;
[0030] Figure 3 It is the set of sequential inner - normal vectors of the sides of convex polygon A in the second embodiment of the present invention;
[0031] Figure 4 It is the set of sequential outer - normal vectors of the sides of convex polygon B in the second embodiment of the present invention;
[0032] Figure 5 It is the first vector in the set of sequential inner - normal vectors of the sides of convex polygon A in the second embodiment of the present invention that is located after the last outer - normal vector of convex polygon B;
[0033] Figure 6 It is E in the second embodiment of the present invention 1 coordinate diagram;
[0034] Figure 7 It is E in the second embodiment of the present invention 2 coordinate diagram;
[0035] Figure 8 It is E in the second embodiment of the present invention 3 coordinate diagram;
[0036] Figure 9 It is E in the second embodiment of the present invention 4 coordinate diagram;
[0037] Figure 10 It is E in the second embodiment of the present invention 5 coordinate diagram;
[0038] Figure 11 This is a schematic diagram of the intrusion block in the second embodiment of the present invention.
[0039] The accompanying drawings are only for illustrative purposes and should not be construed as a limitation of this patent; for better illustration of this embodiment, some components in the drawings may be omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. Detailed implementation manners
[0040] The present invention will be further described below with reference to the accompanying drawings.
[0041] Embodiment 1
[0042] A method for improving the construction efficiency of the mesoscopic model of soil-rock mixture in the embodiment of the present invention. In this method, the construction of the mesoscopic model of soil-rock mixture is divided into two steps: the generation and placement of random boulders. During the modeling process, randomly generated convex polygons are used to replace the boulders in the soil-rock mixture. During the placement process of the random convex polygons, the convex polygon to be placed and the placed convex polygons cannot overlap. To facilitate the determination of whether two convex polygons overlap and the determination of the position of the convex polygon to be placed, the concept of an intrusion block is introduced. Define the placed convex polygon as B and the convex polygon to be placed as A. Assume that a0 is an arbitrarily selected reference point on A. Through a series of calculations, the area represented by the intrusion block formed by the two can be obtained. The intrusion block is related to the shapes, sizes of the convex polygon A, the convex polygon B, and the position of the reference point a0. If a0 is outside the area of the intrusion block or on the boundary of the area, the convex polygon A and the convex polygon B do not overlap. If a0 is inside the area of the intrusion block, the convex polygon A and the convex polygon B overlap. Quickly forming the intrusion blocks of the convex polygon of the boulder to be placed and the placed convex polygons of the boulders will improve the construction efficiency of the mesoscopic model of the soil-rock mixture. The convex polygon A and the convex polygon B are in the same plane;
[0043] Assume that the convex polygon A has m sides and the convex polygon B has n sides. Denote the x and y coordinates of the k-th (1 ≤ k ≤ m) vertex of the convex polygon A as The x and y coordinates of the l-th (1 ≤ l ≤ n) vertex of the convex polygon B are respectively And arbitrarily select a point in the convex polygon A as the reference point, and its x and y coordinates are respectively
[0044] Specifically, it includes the following steps:
[0045] S1. In the actual implementation process, it can be freely selected to proceed in a clockwise or counterclockwise order along the sides. However, once the direction is selected, during this implementation process, the connection directions between the selected vertices, edges, and the vertices of the finally obtained intrusion block body must all be operated in the selected direction and cannot be changed again. According to the coordinates of the two vertices of each edge, calculate the set of sequential inner normal vectors of the edges forming convex polygon A. The inner normal vector of the k-th (1 ≤ k ≤ m - 1) edge of convex polygon A is The inner normal vector of the m-th edge of convex polygon A is
[0046] S2. In the counterclockwise order of the edges in sequence, according to the coordinates of the two vertices of each edge, calculate the set of sequential outer normal vectors of the edges forming convex polygon B. The outer normal vector of the l-th (1 ≤ l ≤ n - 1) edge of convex polygon B is The outer normal vector of the n-th edge of convex polygon B is
[0047] S3. In the set of sequential inner normal vectors of the edges of convex polygon A, find the first vector after the last outer normal vector of convex polygon B ;
[0048] S31. Calculate Let k = 0;
[0049] S32. Let result_last = result, and let k = k + 1, then calculate
[0050] S33. Repeat step S32 until result_last ≤ 0 and result > 0, record this k value, then this is the first vector in the set of sequential inner normal vectors of the edges of convex polygon A after the last outer normal vector of convex polygon B .
[0051] S4. Add vertices to the set of sequential vertices of the intrusion block body in sequence. The polygon formed by connecting the vertices linearly is the intrusion block body.
[0052] S41. Based on the k value obtained in step S33, obtain the first vertex of the intrusion block body, and its x and y coordinates are: Let k_flag = k, and let l = 1;
[0053] S42. As Figure 1 shown, calculate If result > 0, then let l = l + 1; if result = 0, then let k = k + 1 and l = l + 1; if result < 0, then let k = k + 1;
[0054] S43: If l > n at this time, then jump to step S46;
[0055] If l ≤ n at this time, then perform step S44;
[0056] S44: If k > m, then let k = 1 and add a new vertex to the sequential vertex set of the intruded block, whose x and y coordinates are respectively
[0057] If k ≤ m, then add a new vertex to the sequential vertex set of the intruded block, whose x and y coordinates are respectively
[0058] S45: Repeat S42 - S44 until l = n and k = k_flag;
[0059] S46: Using the coordinates obtained in step S41 as the first vertex of the intruded block, sequentially connect the vertices of the intruded block obtained in S42 - S45, which is the intruded block.
[0060] Embodiment 2
[0061] This embodiment gives a specific calculation process. After implementing the algorithm through self - programming using conventional software such as C / vb / matlab / python, it can be implemented.
[0062] As Figure 2 shown, the convex polygon A has 3 sides and B has 4 sides, so m = 3, n = 4. In the counter - clockwise order, the three vertex coordinates of the convex polygon A are (-2, 0), (-0.5, -0.8), (-0.5, 0) in sequence, and the four vertex coordinates of the convex polygon B are (0, 0), (2, 0), (2, 1), (0, 1) in sequence. Select an arbitrary point α 0 in the block A as the reference point. Here, the point (-0.9, -0.3) is selected. The horizontal coordinate is the x - axis and the vertical coordinate is the y - axis.
[0063] The figures, points, and vectors in the examples are just a display of the original graphic data, point data, and vector data. For example, the 4 vertex coordinates of the convex polygon B in the figure are (0, 0), (2, 0), (2, 1), (0, 1), which naturally correspond to the convex polygon B in the figure.
[0064] S1: As Figure 2 shown, the set of sequential inner - normal vectors of the sides of the convex polygon A is
[0065] {[0.8 1.5] [-0.8 0] [0 -1.5]};
[0066] S2. As Figure 3 shown, the set of sequential outer normal vectors of the sides of the convex polygon B is
[0067] {[0 -2] [1 0] [0 2] [-1 0]};
[0068] S3. Among the set of sequential inner normal vectors of the sides of the convex polygon A, find the first vector after the last outer normal vector of the convex polygon B ;
[0069] S31. Calculate Let k = 0;
[0070] S32. Let result_last = result = 1.5, and let k = k + 1 = 0 + 1 = 1, calculate
[0071]
[0072] Need to continue to execute S32;
[0073] Let result_last = result = -1.5, and let k = k + 1 = 1 + 1 = 2, calculate
[0074]
[0075] Need to continue to execute S32;
[0076] Let result_last = result = 0, and let k = k + 1 = 2 + 1 = 3, calculate
[0077]
[0078] result_last = 0 ≤ 0, result = 1.5 > 0, can execute S33;
[0079] S33. At this time, k = 3, as Figure 5 shown, is the first vector in the set of sequential inner normal vectors of the sides of the convex polygon A after the last outer normal vector of B ;
[0080] S4. Add vertices to the set of sequential vertices of the intrusion block E in sequence, and the polygon formed by connecting the vertices linearly is the intrusion block E.
[0081] S41. As Figure 6As shown, according to the value of k obtained in step S33, k = 3, the first vertex of the intruded block is obtained, and its coordinates are:
[0082]
[0083] That is Figure 6 E in 1 point, let k_flag = k = 3, and let l = 1;
[0084] S42. According to Figure 1 the flowchart shown, calculate
[0085] Since result = 0, then let k = k + 1 = 3 + 1 = 4, and let l = l + 1 = 1 + 1 = 2;
[0086] S43. l = 2 ≤ n (n = 4), then perform step S44;
[0087] S44. k = 4 > m (m = 3), then let k = 1, and add a new vertex E 2 to the sequential vertex set of the intruded block, and its x and y coordinates are respectively
[0088]
[0089] as Figure 7 shown by E in 2 point;
[0090] S45. Repeat S42 - S44; because l = 2, k = 1, and n = 4, k_flag = 3, the condition for exiting the repeated execution is not met;
[0091] The following is the second execution of S42 - S44, with 2 added before S for distinction:
[0092] 2S42.
[0093] result > 0, let l = l + 1 = 2 + 1 = 3,
[0094] 2S43. l = 3 ≤ n (n = 4), then perform step S44;
[0095] 2S44. k = 1 ≤ m (m = 3), add a new vertex E 3 to the sequential vertex set of the intruded block, and its x and y coordinates are respectively
[0096]
[0097] as Figure 8 shown by E in 3 point;
[0098] 2S45. Repeat steps S42 - S44; since l = 3, k = 1, and n = 4, k_flag = 3, the condition for exiting the repeated execution is not met;
[0099] The following is the third execution of S42 - S44, with 3 added before S for distinction:
[0100] 3S42.
[0101] result < 0, let k = k + 1 = 1 + 1 = 2,
[0102] 3S43. Since l = 3 ≤ n (n = 4), proceed to step S44;
[0103] 3S44. Since k = 2 ≤ m (m = 3), add a new vertex E to the sequential vertex set of the intruded block body 4 , whose x and y coordinates are
[0104]
[0105] as Figure 9 the E point shown in 4 ;
[0106] 3S45. Repeat steps S42 - S44; since l = 3, k = 2, and n = 4, k_flag = 3, the condition for exiting the repeated execution is not met;
[0107] The following is the fourth execution of S42 - S44, with 4 added before S for distinction:
[0108] 4S42.
[0109] result > 0, let l = l + 1 = 3 + 1 = 4,
[0110] 4S43. Since l = 4 ≤ n (n = 4), proceed to step S44;
[0111] 4S44. Since k = 2 ≤ m (m = 3), add a new vertex E to the sequential vertex set of the intruded block body 5 , whose x and y coordinates are
[0112]
[0113] as Figure 10 the E point shown in 5 ;
[0114] 4S45. Repeat steps S42 - S44; since l = 4, k = 2, and n = 4, k_flag = 3, the condition for exiting the repeated execution is not met;
[0115] The following is the fifth execution of S42 - S44, with a "5" added before S for distinction:
[0116] 5S42,
[0117] result = 0, let k = k + 1 = 2 + 1 = 3, and let l = l + 1 = 4 + 1 = 5;
[0118] 5S43, l = 5 > n (n = 4), then jump to step S46.
[0119] S46. Using E 1 as the first vertex of the intrusion block, successively connect the E 2 , E 3 , E 4 , E 5 obtained in the previous steps in a counterclockwise direction, which is the intrusion block, as shown by the dashed line in Figure 11 .
[0120] This embodiment does not impose any formal restrictions on the shape, material, structure, etc. of the present invention. Any simple modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of the present invention all fall within the protection scope of the technical solution of the present invention.
[0121] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation on the protected content of the present invention.
[0122] If terms such as "first" and "second" are used in this article to limit components, those skilled in the art should be aware that the use of "first" and "second" is only for the convenience of describing the present invention and simplifying the description. Without additional statements, the above terms have no special meanings.
[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features, but these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for improving the construction efficiency of the mesoscopic model of soil-rock mixture. In this method, the construction of the mesoscopic model of soil-rock mixture is divided into two steps: the generation and placement of random boulders. During the modeling process, randomly generated convex polygons are used to replace the boulders in the soil-rock mixture. During the placement process of the random convex polygons, the convex polygon to be placed cannot overlap with the already placed convex polygons. In order to facilitate the determination of whether two convex polygons overlap and the determination of the position of the convex polygon to be placed, the concept of the intrusion block is introduced. Define the already placed convex polygon as B and the convex polygon to be placed as A. Assume that a0 is any selected reference point on A. Through a series of calculations, the area represented by the intrusion block formed by the two can be obtained. The intrusion block is related to the shapes, sizes of the convex polygon A, convex polygon B, and the position of the reference point a0. If a0 is outside the intrusion block area or on the boundary of the area, then the convex polygon A and the convex polygon B do not overlap. If a0 is inside the intrusion block area, then the convex polygon A and the convex polygon B overlap. Quickly forming the intrusion block of the convex polygon of the boulder to be placed and the convex polygon of the already placed boulder will improve the construction efficiency of the mesoscopic model of soil-rock mixture. The convex polygon A and the convex polygon B are in the same plane; Suppose convex polygon A has m sides and convex polygon B has n sides. Denote the x and y coordinates of the k-th (1 ≤ k ≤ m) vertex of convex polygon A as The x and y coordinates of the l-th (1 ≤ l ≤ n) vertex of convex polygon B are And arbitrarily select a reference point in convex polygon A, whose x and y coordinates are Characterized in that, It includes the following steps: S1. In the counterclockwise order of the sides, calculate the set of inner normal vectors of the sides forming the convex polygon A according to the coordinates of the two vertices of each side. The inner normal vector of the k-th (1 ≤ k ≤ m - 1) side of the convex polygon A is The inner normal vector of the m-th side of the convex polygon A is S2. In the counterclockwise order of the sides, calculate the set of outwards normal vectors of the sides forming the convex polygon B according to the coordinates of the two vertices of each side. The outwards normal vector of the \(l\)th (\(1\leq l\leq n - 1\)) side of the convex polygon B is The outwards normal vector of the \(n\)th side of the convex polygon B is S3. Among the set of the normal vectors of the sides of the convex polygon A in the order of the sides, find the first vector after the last external normal vector of the convex polygon B; After that; S31. Calculate Let k = 0; S32. Let result_last = result, and let k = k + 1, then calculate S33. Repeat step S32 until result_last ≤ 0 and result > 0, record this k value, then this is the first vector after the last outer normal vector of convex polygon B among the set of sequential inner normal vectors of the sides of convex polygon A; after that. S4. Add vertices to the sequential vertex set of the intrusion block in sequence, and the polygon formed by connecting the vertices linearly is the intrusion block.
2. A method for improving the construction efficiency of the mesoscopic model of soil-rock mixture according to claim 1, Characterized in that, The step S4 further includes the following steps: S41. Based on the k value obtained in step S33, obtain the first vertex of the intruded block, and its x and y coordinates are: Let k_flag = k and l = 1; S42. Calculate If result > 0, then let l = l + 1. If result = 0, then let k = k + 1 and let l = l + 1. If result < 0, then let k = k + 1; S43. If l > n at this time, jump to step S46; If l ≤ n at this time, perform step S44; S44. If k > m, then set k = 1 and add a new vertex to the sequential vertex set of the intruded block body, with its x and y coordinates being If k ≤ m, add a new vertex to the sequential vertex set of the intruded block, with its x and y coordinates being S45. Repeat S42 - S44 until l = n and k = k_flag; S46. Take the coordinates obtained in step S41 as the first vertex of the intrusion block, and connect the vertices of the intrusion block obtained in S42 - S45 in sequence, which is the intrusion block.