Simulation method of three-dimensional irregular complex heterostructure body in rock-soil stratum

Abstract

The invention discloses a simulation method for a three-dimensional irregular complex heterostructure body in a rock-soil stratum, and belongs to the technical field of simulation of the irregular heterostructure body in the rock-soil stratum. A physical and morphological parameter statistical characteristic database of the irregular heterostructure body is established, and finite element analysis software is used for establishing a three-dimensional rock-soil stratum finite element model; according to the method, database variable parameters are utilized to associate irregular heterostructure target parameters with subprogram self-defined field variables, and the spatial form of the heterostructure is flexibly adjusted through parameters such as related length and inclination angle so as to reasonably characterize any existence state of the heterostructure in the space. According to the method, the physical and morphological statistical characteristics of the irregular heterostructure body can be effectively considered, the situation that an analysis model is deviated from engineering practice due to too many assumptions is avoided, meanwhile, the limitation of a two-dimensional plane model is broken through, and a powerful way is provided for construction and computational analysis of a three-dimensional rock-soil stratum model containing the irregular complex heterostructure under the complex geological condition.

Description

Technical Field

[0001] The invention relates to the technical field of simulation of irregular heterogeneous structures in rock formations, and in particular to a simulation method of three-dimensional irregular complex heterogeneous structures in rock formations. Background Art

[0002] With the continuous improvement of the intelligent level of construction equipment, my country's water conservancy and hydropower, geotechnical, transportation, underground space and other engineering fields have developed rapidly, creating favorable conditions for promoting efficient and high-quality construction of projects. However, due to the need for the continuous expansion of infrastructure construction, the project has been continuously expanded to more remote areas and deeper formations, and the geological conditions encountered are more complex and highly unpredictable, which in turn affects the safety and reliability of the project to a certain extent.

[0003] In engineering practice, irregular heterogeneous structures in the strata, such as weak interlayers, fracture zones, and fissure structural surfaces, are complex geological conditions often encountered in the excavation of large underground caverns, steep slopes, and deep foundations. Due to the long-term evolution of complex geological structures, the spatial distribution of heterogeneous structures in the strata usually has a certain tendency. Secondly, the difference in material composition leads to large differences in the physical and mechanical properties of heterogeneous structures from the surrounding rock and soil, which may cause large uneven deformation of the engineering structure. If support is not carried out in time, it may even cause large-scale collapse of the rock and soil, posing a great threat to the safety of life and property of construction and production personnel.

[0004] When modeling and analyzing complex terrain and geological conditions of an engineering project, existing numerical techniques rarely consider the three-dimensional irregular complex heterogeneous structures inside the strata. There are three main deficiencies: first, most of them are based on two-dimensional plane models for analysis, which cannot consider the three-dimensional real state; second, they simulate a single object, which is not flexible; third, they do not effectively consider the statistical characteristics of heterogeneous structures, which deviates from the actual geological conditions to a certain extent. The above deficiencies will greatly underestimate the impact of irregular heterogeneous structures on the overall stability performance of the project.

[0005] Based on this, existing methods are difficult to solve this type of problem, and there is an urgent need to propose a simulation method for three-dimensional irregular and complex heterogeneous structures inside rock strata that can effectively consider the statistical characteristics of exploration data. Summary of the invention

[0006] In order to solve the current technical problems, the main purpose of the present invention is to provide a simulation method for three-dimensional irregular complex heterogeneous structures inside rock strata, thereby solving the technical problem that existing simulation methods are difficult to effectively characterize the true form of irregular heterogeneous structures, and thus cannot effectively evaluate the impact of irregular complex heterogeneous structures on the overall stability of the project.

[0007] The technical solution adopted by the present invention is: a method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock layer, comprising the following steps: S1. Based on the exploration data of irregular heterogeneous structures in rock and soil strata, a statistical characteristic database of physical and morphological parameters of irregular heterogeneous structures is obtained; S2. According to the actual site geometry, a three-dimensional finite element model is established, the model boundary conditions are set, the load conditions are defined, and the unit grid is divided, and the target parameters of the irregular heterogeneous structure are associated with the field variables; S3, using database variable parameters to transfer irregular heterogeneous structure target parameters; S4, selecting a number of sub-regions in the horizontal direction of the probability density function of the standard normal distribution as the defining conditions for the subsequent determination of the medium region to which the random base belongs; S5, generating a three-dimensional Gaussian random field; S6. Rotate the Gaussian random field according to the actual exploration situation to characterize the inclination angle of the irregular heterogeneous structure in space; S7. Use Gaussian random field correlation length to describe the relative length of irregular heterogeneous structures in space; S8, determining the medium region where the Gaussian random value generated at the integral point is located, and when the point is located in a different region, replacing the random value of the point with a similar analytical physical quantity of the corresponding medium; S9. Perform finite element calculations, export the calculation result cloud map, and display the three-dimensional rock and soil stratum model containing irregular and complex heterogeneous structures.

[0008] In S1, the geological structure data obtained by exploration is analyzed by big data, the data variation law is mined, and the physical and morphological parameter statistical characteristic database of irregular heterogeneous structures is summarized to establish the database W={ c, l, t, α},in c represents the analytical physical quantity, l Indicates relative length, t Relative thickness, α Indicates the relative inclination.

[0009] In S2, the steps of establishing a three-dimensional finite element model are: A three-dimensional finite element model was established, and the displacement boundary conditions at the bottom of the model were set as fixed constraints, the displacement boundary conditions around the model were set as vertical constraints, and the displacement boundary conditions on the upper surface were set as free boundaries. A vertical gravity load was applied, and the model unit grid was divided using the three-dimensional eight-node hexahedron C3D8R unit type. The finite element model was exported as an INP calculation source file, and the target parameters of the irregular heterogeneous structure were associated with the field variables of the USDFLD embedded subroutine of the finite element analysis software ABAQUS in the INP file. In S3, secondary development is carried out based on the USDFLD interface of the finite element analysis software ABAQUS subroutine. The database variable parameters are used to indirectly transfer the target parameters of the irregular heterogeneous structure through the Gaussian random field to characterize the morphology of the irregular heterogeneous structure in space.

[0010] In S4, several sub-regions are selected in the horizontal direction of the standard normal distribution probability density function as the delimiting conditions for the subsequent judgment of the medium region to which the random base belongs. The width of a single sub-region affects the relative thickness of the heterogeneous structure, and the percentage of the total area of ​​the region represents the spatial distribution proportion of the heterogeneous structure in the model.

[0011] In S5, the modified linear estimation method is used to generate a three-dimensional Gaussian random field, and the square exponential autocorrelation function is used to describe the spatial correlation of the parameters. Its mathematical expression is as follows: (1); In formula (1): R ( x , y , z ) is the square exponential correlation function; Δ x , Δ y , Δ z are the relative distances between any two points in space in the directions of the three coordinate axes; l x , l y , l z They are the relevant lengths of the target parameters in the directions of the three coordinate axes.

[0012] In S6, the angle α Rotate the three-dimensional Gaussian random field generated in S5 around Z The relative distances of the three coordinate axes after axis rotation are expressed as: (2); In formula (2): Δ x , Δ y , Δ z Indicates the relative distance between any two points in the space in the three coordinate axis directions before rotation; Δ xʹ , Δ yʹ , Δ zʹ Indicates the relative distance between any two points in the space after rotation in the directions of the three coordinate axes; Substituting formula (2) into formula (1), we can get Z The square exponential correlation function after axis rotation is expressed as: (3); In formula (3): is the rotated square exponential correlation function. In S7, according to the definition of correlation function in Gaussian random field, the correlation function correlation length is used to describe the relative length of the irregular heterostructure in space.

[0013] In S8, the medium region where the Gaussian random value is located is determined. If the Gaussian random value generated at the integral point is within the defined area, the point belongs to the heterogeneous structure region, and the random value of the point is replaced by the numerical value of the physical quantity analyzed by the heterogeneous structure; if it is not within the defined area, the point belongs to the surrounding rock and soil region, and the random value of the point is replaced by the numerical value of the same analytical physical quantity of the surrounding rock and soil.

[0014] In S9, the USDFLD subroutine is called in the finite element analysis software ABAQUS to perform finite element calculations, the ODB calculation result file is opened, the subroutine custom field variable SDV is used as the output variable, and the calculation result cloud map is exported to display the three-dimensional rock formation model containing irregular complex heterogeneous structures.

[0015] The present invention has the following beneficial effects: 1. The present invention can effectively consider the physical and morphological statistical characteristics of irregular heterogeneous structures, has strong flexibility, and provides a feasible way to more realistically characterize the existence state of irregular complex heterogeneous structures in space, effectively avoiding too many assumptions in the analysis model and deviating from the actual engineering situation.

[0016] 2. The present invention can make use of the specific advantages of secondary development of subroutines to efficiently couple finite element grids of arbitrary shapes with random fields, achieving a technical breakthrough in seamlessly connecting the target random response of irregular heterogeneous structures with the finite element three-dimensional model, saving a lot of computing resources and time.

[0017] 3. The present invention can directly generate a three-dimensional stratum model containing irregular complex heterogeneous structures, breaking through the limitations of two-dimensional plane models and providing a powerful tool for calculating special working conditions such as local instability of models in limited spaces.

[0018] 4. The concept of heterogeneous structure referred to in the present invention is broad, covering engineering stability and seepage analysis in many fields such as water conservancy and hydropower, geotechnical engineering, and transportation. It provides a powerful way to construct and calculate three-dimensional models of irregular heterogeneous structures under complex geological conditions, and has good economic benefits and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 The present invention is a flow chart of a method for simulating a three-dimensional rock and soil stratum model containing an irregular complex heterogeneous structure.

[0021] Figure 2 It is the model geometric dimensions in the three-dimensional formation model of the embodiment of the present invention.

[0022] Figure 3 It is the corresponding finite element model in the three-dimensional formation model of the embodiment of the present invention.

[0023] Figure 4 Schematic diagram of the standard normal distribution probability density curve for defining the heterogeneous structure region in the present invention.

[0024] Figure 5 The Gaussian random field of the present invention is Z Schematic diagram of the relevant lengths before and after the axis rotation; Figure a is the schematic diagram before rotation, and Figure b is the schematic diagram after rotation.

[0025] Figure 6 This is an embodiment of a three-dimensional rock and soil stratum model containing an irregular complex heterogeneous structure in an embodiment of the present invention; wherein the inclination angle relative to the horizontal plane is 0°.

[0026] Figure 7 This is an embodiment of a three-dimensional rock and soil stratum model containing an irregular complex heterogeneous structure in an embodiment of the present invention; wherein the inclination angle relative to the horizontal plane is 30°.

[0027] Figure 8 This is an embodiment of a three-dimensional rock and soil stratum model containing an irregular complex heterogeneous structure in an embodiment of the present invention; wherein the inclination angle relative to the horizontal plane is 150°. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In actual engineering, irregular complex heterogeneous structures are widely present in rock formations, and have high concealment and position uncertainty. Using efficient simulation methods to characterize their possible existence forms in space has important engineering practical significance for effectively revealing the mechanism of physical response changes inside the formation. To this end, the present invention further elaborates on the technical solution proposed by the present invention through an embodiment of a rectangular formation model containing irregular complex heterogeneous structures.

[0030] See also Figure 1 The embodiment of the present invention provides a method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation, comprising the following steps: S1. Based on the exploration data of irregular heterogeneous structures in rock and soil strata, a database of statistical characteristics of physical and morphological parameters of irregular heterogeneous structures is obtained.

[0031] Specifically, in S1, the geological structure data obtained by exploration is analyzed by big data, the data variation law is mined, and a statistical characteristic database of physical and morphological parameters of irregular heterogeneous structures is formed, and a database W={ c, l, t, α},in c represents the analytical physical quantity, l Indicates relative length, t Relative thickness, α Indicates the relative inclination angle and sets the initial value.

[0032] S2. According to the actual site geometry, a three-dimensional finite element model is established, the model boundary conditions are set, the load conditions are defined, and the unit grid is divided to associate the target parameters of the irregular heterogeneous structure with the field variables.

[0033] Specifically, in S2, the steps of establishing a three-dimensional finite element model are: The finite element analysis software ABAQUS was used to establish a three-dimensional finite element model. According to the geometric dimensions of the cuboid, such as Figure 2 , 3 As shown in the figure, a finite element model is created by means of an interactive interface, basic material parameters are set, the displacement boundary condition at the bottom of the model is set as a fixed constraint, the displacement boundary conditions around the model are set as a vertical constraint, that is, the normal displacement is 0, but sliding is allowed along the surface, the displacement boundary condition on the upper surface is set as a free boundary, a vertical gravity load is applied, and a three-dimensional eight-node hexahedron C3D8R unit type is used to refine the model unit grid to ensure a smooth transition of the interface simulation between the heterogeneous structure and the surrounding rock and soil. The finite element model is exported as an INP calculation source file, and the strength parameters of the irregular heterogeneous structure are associated with the field variables of the ABAQUS embedded subroutine USDFLD in the INP file, and the custom field variable SDV is set as the unit output field variable.

[0034] The specific contents of the modification statements in the INP file are as follows: * MATERIALS *Depvar 1, *Mohr Coulomb Hardening, dependencies=1 1,0, 0 , 1 20,0, 0 , 20 100,0, 0, 100 300,0,0, 300 *User Defined Field * FIELD OUTPUT *Element Output, directions=YES SDV Specifically, start ABAQUS / CAE: open the software and select the appropriate workspace; Import or create geometry: If you already have the geometry of a cuboid, you can directly enter those dimensions to create a new part, or you can import existing geometry.

[0035] Define material properties: Enter the Property module and define the required basic material parameters, such as elastic modulus, Poisson's ratio, etc.

[0036] Set mesh division: Select the Mesh module and use the C3D8R unit type to refine the model unit mesh to ensure a smooth transition between the interface between the heterogeneous structure and the surrounding rock and soil.

[0037] Apply gravity load: Add a gravity load in the Load module, with the direction vertically downward.

[0038] S3. Use database variable parameters to transfer target parameters of irregular heterogeneous structures.

[0039] In S3, secondary development is carried out based on the ABAQUS embedded subroutine USDFLD interface. In the subroutine custom area, FORTRAN language is used to write codes from three modules: random field generation, morphology adjustment, and medium determination. Database variable parameters are fully utilized to indirectly transfer irregular heterogeneous structure target parameters through Gaussian random fields to reasonably characterize the possible existing forms of heterogeneous structures in space. The specific format of the subroutine USDFLD and the code writing partition are shown as follows: SUBROUTINE USDFLD (FIELD, STATEV, PNEWDT, DIRECT, T, CELENT, TIME,DTIME, CMNAME, ORNAME, NFIELD, NSTATV, NOEL, NPT, LAYER, KSPT, KSTEP, KINC,NDI, NSHR, COORD, JMAC, JMATYP, MATLAYO, LACCFLA) INCLUDE 'ABA_PARAM.INC' CHARACTER*80 CMNAME,ORNAME CHARACTER*3FLGRAY(15) DIMENSION FIELD(NFIELD),STATEV(NSTATV),DIRECT(3,3), T(3,3),TIME(2) DIMENSION ARRAY(15),JARRAY(15),JMAC(*),JMATYP(*), COORD(*) ! (The following is the user code customization area) ! Random field generation code area ! Irregular heterogeneous structure morphology setting area ! Random medium determination area RETURN END The whole process is decomposed into three key steps: Gaussian random field generation, morphology adjustment and medium determination.

[0040] S4. Select several sub-regions in the horizontal direction of the standard normal distribution probability density function as the boundary conditions for subsequent determination of the medium region to which the random base belongs.

[0041] In S4, several sub-regions are selected in the horizontal direction of the standard normal distribution probability density function as the delimiting conditions for the subsequent judgment of the medium region to which the random base belongs. The width of a single sub-region affects the relative thickness of the heterogeneous structure, and the percentage of the total area of ​​the region represents the spatial distribution proportion of the heterogeneous structure in the model.

[0042] For details, see Figure 4 , select several sub-areas in the horizontal direction of the standard normal distribution probability density function Q i ( m , n ),in i is the number of intervals, m andn are the lower and upper bounds of the selected interval, respectively, and serve as the defining conditions for the subsequent determination of the medium region to which the random base belongs (heterogeneous structure or surrounding rock and soil). The width of a single sub-region directly affects the relative thickness of the heterogeneous structure, and the total area of ​​the region Q The percentage represents the spatial distribution ratio of the heterogeneous structure in the model. In the embodiment of the present invention, four sub-areas are selected, namely Q 1(-1.85, -1.45), Q 2(-1.15, -0.85), Q 3(1.25, 1.75), Q 4(0.35, 0.75).

[0043] S5. Generate a three-dimensional Gaussian random field.

[0044] In S5, a random field simulation method is used to generate a three-dimensional Gaussian random field. Compared with other methods, the modified linear estimation method has the significant advantages of being able to organically integrate with finite element meshes of arbitrary shapes and having a fast generation efficiency. To this end, the present invention uses a modified linear estimation method to generate a three-dimensional Gaussian random field, and accordingly uses a square exponential autocorrelation function to describe the spatial correlation of parameters, and its mathematical expression is as follows: (1); In formula (1): R ( x , y , z ) is the square exponential correlation function; Δ x , Δ y , Δ z are the relative distances between any two points in space in the directions of the three coordinate axes; l x , l y , l z They are the relevant lengths of the target parameters in the directions of the three coordinate axes.

[0045] S6. Rotate the Gaussian random field according to the actual exploration situation to characterize the inclination angle of the irregular heterogeneous structure in space.

[0046] In S6, in order to effectively characterize the inclination angle of the irregular heterostructure in any direction in space, the angle α The Gaussian random field described in S5 is rotated to reflect the complex and changeable characteristics of the spatial distribution of the irregular heterogeneous structure. Figure 5 , only consider the coordinate axis perpendicular to the paper plane, that is, ZThe axis rotates, and after the rotation, the relative distances of the three coordinate axes in equation (1) can be expressed as: (2); In formula (2): Δ x , Δ y , Δ z Indicates the relative distance between any two points in the space in the three coordinate axis directions before rotation; Δ xʹ , Δ yʹ , Δ zʹ Indicates the relative distance between any two points in the space after rotation in the directions of the three coordinate axes; Substituting formula (2) into formula (1), the square exponential correlation function after rotation around the Z axis can be expressed as: (3); In formula (3): is the rotated square exponential correlation function. S7. Use Gaussian random field correlation length to describe the relative length of irregular heterostructures in space.

[0047] In S7, according to the definition of the correlation function in the Gaussian random field, the correlation length can effectively characterize the spatial correlation of the material parameters. For this reason, the correlation length of the correlation function is indirectly used to describe the relative length of the irregular heterostructure in space. In the embodiment of the present invention, the correlation lengths in the three directions in formula (3) are l x , l y , l z The initial values ​​are set to 20m, 2m, and 20m respectively.

[0048] S8. Determine the medium region where the Gaussian random value generated at the integral point is located. When the point is located in a different region, replace the random value of the point with a similar analytical physical quantity of the corresponding medium.

[0049] In S8, the medium region where the Gaussian random value is located is determined. If the Gaussian random value generated at the integral point is within the defined area, the point belongs to the heterogeneous structure region, and the random value of the point is replaced by the numerical value of the physical quantity analyzed by the heterogeneous structure; if it is not within the defined area, the point belongs to the surrounding rock and soil region, and the random value of the point is replaced by the numerical value of the same analytical physical quantity of the surrounding rock and soil.

[0050] Specifically, determine the medium area where the Gaussian random value is located. If the Gaussian random value generated at the integration point is within the defined area range QIf the point is within the defined area, it belongs to the heterogeneous structure area, and the random value of the point is replaced by the strength value of the heterogeneous structure. In the embodiment of the present invention, the value is 10 kPa. If the point is not within the defined area, it belongs to the surrounding rock and soil area, and the random value of the point is replaced by the strength value of the surrounding rock and soil. In the embodiment of the present invention, the value is 40 kPa.

[0051] S9. Perform finite element calculations, export the calculation result cloud map, and display the three-dimensional rock and soil stratum model containing irregular and complex heterogeneous structures.

[0052] In S9, the USDFLD subroutine is called in the CAE interactive interface in ABAQUS to perform finite element calculations, the ODB calculation result file is opened, the subroutine custom field variable SDV is used as the output variable, and the calculation result cloud map is exported to display the three-dimensional rock formation model containing irregular complex heterogeneous structures. Figures 6 to 8 shown.

[0053] from Figures 6 to 8 It can be seen that the technical method proposed in the present invention can more finely characterize the existence state of irregular complex heterogeneous structures in the three-dimensional model, the interface between the two media is relatively smooth, and the spatial geometric characteristics of the heterogeneous structure are obvious. This example further illustrates the uniqueness and effectiveness of the technical method proposed in the present invention in efficiently simulating irregular complex heterogeneous structures inside the formation.

[0054] The above embodiments are only used to illustrate the present invention, wherein the structure, connection mode and manufacturing process of each component may be changed. Any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation, characterized in that: The following steps are involved: S1. Based on the exploration data of irregular heterogeneous structures in rock and soil strata, a statistical characteristic database of physical and morphological parameters of irregular heterogeneous structures is obtained; S2. According to the actual site geometry, a three-dimensional finite element model is established, the model boundary conditions are set, the load conditions are defined, and the unit grid is divided, and the target parameters of the irregular heterogeneous structure are associated with the field variables; S3, using database variable parameters to transfer irregular heterogeneous structure target parameters; S4, selecting a number of sub-regions in the horizontal direction of the probability density function of the standard normal distribution as the defining conditions for the subsequent determination of the medium region to which the random base belongs; S5, generating a three-dimensional Gaussian random field; S6. Rotate the Gaussian random field according to the actual exploration situation to characterize the inclination angle of the irregular heterogeneous structure in space; S7. Use Gaussian random field correlation length to describe the relative length of irregular heterogeneous structures in space; S8, determining the medium region where the Gaussian random value generated at the integral point is located, and when the point is located in a different region, replacing the random value of the point with a similar analytical physical quantity of the corresponding medium; S9. Perform finite element calculations, export the calculation result cloud map, and display the three-dimensional rock and soil stratum model containing irregular and complex heterogeneous structures.

2. The method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation according to claim 1, characterized in that: In S1, the geological structure data obtained by exploration is analyzed by big data, the data variation law is mined, and the physical and morphological parameter statistical characteristic database of irregular heterogeneous structures is summarized to establish the database W={ c, l, t, α },in c represents the analytical physical quantity, l Indicates relative length, t Relative thickness, α Indicates the relative inclination.

3. The method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation according to claim 1, characterized in that: In S2, the steps of establishing a three-dimensional finite element model are: A three-dimensional finite element model was established, and the displacement boundary conditions at the bottom of the model were set as fixed constraints, the displacement boundary conditions around the model were set as vertical constraints, and the displacement boundary conditions on the upper surface were set as free boundaries. A vertical gravity load was applied, and the model unit grid was divided using the three-dimensional eight-node hexahedron C3D8R unit type. The finite element model was exported as an INP calculation source file, and the target parameters of the irregular heterogeneous structure were associated with the field variables of the USDFLD embedded subroutine of the finite element analysis software ABAQUS in the INP file.

4. The method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation according to claim 3, characterized in that: In S3, secondary development is carried out based on the USDFLD interface of the finite element analysis software ABAQUS subroutine. The database variable parameters are used to indirectly transfer the target parameters of the irregular heterogeneous structure through the Gaussian random field to characterize the morphology of the irregular heterogeneous structure in space.

5. The method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation according to claim 1, characterized in that: In S4, several sub-regions are selected in the horizontal direction of the standard normal distribution probability density function as the delimiting conditions for the subsequent judgment of the medium region to which the random base belongs. The width of a single sub-region affects the relative thickness of the heterogeneous structure, and the percentage of the total area of ​​the region represents the spatial distribution proportion of the heterogeneous structure in the model.

6. The method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation according to claim 1, characterized in that: In S5, the modified linear estimation method is used to generate a three-dimensional Gaussian random field, and the square exponential autocorrelation function is used to describe the spatial correlation of the parameters. Its mathematical expression is as follows: （1）； In formula (1): R ( x , y , z ) is the square exponential correlation function; Δ x , Δ y , Δ z are the relative distances between any two points in space in the directions of the three coordinate axes; l x , l y , l z They are the relevant lengths of the target parameters in the directions of the three coordinate axes.

7. The method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation according to claim 6, characterized in that: In S6, the angle α Rotate the three-dimensional Gaussian random field generated in S5 around Z The relative distances of the three coordinate axes after axis rotation are expressed as: （2）； In formula (2): Δ x , Δ y , Δ z Respectively represent the relative distances between any two points in the space before rotation in the directions of the three coordinate axes; Δ xʹ , Δ yʹ , Δ zʹ Respectively represent the relative distances between any two points in the space after rotation in the directions of the three coordinate axes; Substituting formula (2) into formula (1), we can get Z The square exponential correlation function after axis rotation is expressed as: （3） ； In formula (3): is the rotated square exponential correlation function.

8. The method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation according to claim 1, characterized in that: In S7, according to the definition of correlation function in Gaussian random field, the correlation function correlation length is used to describe the relative length of the irregular heterostructure in space.

9. The method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation according to claim 1, characterized in that: In S8, the medium region where the Gaussian random value is located is determined. If the Gaussian random value generated at the integral point is within the defined area, the point belongs to the heterogeneous structure region, and the random value of the point is replaced by the numerical value of the physical quantity analyzed by the heterogeneous structure; if it is not within the defined area, the point belongs to the surrounding rock and soil region, and the random value of the point is replaced by the numerical value of the same analytical physical quantity of the surrounding rock and soil.

10. The method for simulating a three-dimensional irregular complex heterogeneous structure inside a rock formation according to claim 1, characterized in that: In S9, the USDFLD subroutine is called in the finite element analysis software ABAQUS to perform finite element calculations, the ODB calculation result file is opened, the subroutine custom field variable SDV is used as the output variable, and the calculation result cloud map is exported to display the three-dimensional rock formation model containing irregular complex heterogeneous structures.

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