A simulation method for three-dimensional irregular complex heterogeneous structures inside rock and soil strata

Abstract

The present invention discloses a method for simulating three-dimensional irregular complex heterogeneous structures within a rock formation, belonging to the technical field of simulating irregular heterogeneous structures in rock formations. The method establishes a database of statistical characteristics of physical and morphological parameters of irregular heterogeneous structures, uses finite element analysis software to establish a three-dimensional rock formation finite element model, utilizes database variable parameters to associate target parameters of the irregular heterogeneous structure with subroutine custom field variables, and flexibly adjusts the spatial morphology of the heterogeneous structure through parameters such as correlation length and inclination to reasonably characterize any state of existence of the heterogeneous structure in space. The present invention can effectively consider the physical and morphological statistical characteristics of irregular heterogeneous structures, avoid deviating from engineering practice due to excessive assumptions in the analysis model, and at the same time break through the limitations of two-dimensional plane models, providing a powerful approach for constructing and calculating three-dimensional rock formation models containing irregular complex heterogeneous structures under complex geological conditions.

Description

Technical Field

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

[0002] With the continuous improvement of intelligent construction equipment, my country's water conservancy and hydropower, geotechnical engineering, transportation, underground space and other engineering fields have developed rapidly, creating favorable conditions for promoting efficient and high-quality construction. However, due to the continued expansion of infrastructure construction, projects are expanding to more remote areas and deeper formations, encountering more complex and unpredictable geological conditions, which in turn affects project safety and reliability 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 significant differences in the physical and mechanical properties of heterogeneous structures from the surrounding rock and soil. This may cause large uneven deformation of the engineering structure. If support is not provided in time, it may even cause large-scale collapse of the rock and soil, posing a significant threat to the safety of life and property of construction workers.

[0004] When modeling and analyzing complex terrain and geological conditions for projects, existing numerical techniques rarely consider the three-dimensional, irregular, and complex heterogeneous structures within the strata. This is primarily due to three shortcomings: First, most analyses are based on two-dimensional planar models, failing to account for true three-dimensional conditions; second, simulations focus on a single object, limiting flexibility; and third, they fail to effectively consider the statistical characteristics of heterogeneous structures, deviating to a certain extent from actual geological conditions. These shortcomings significantly underestimate the impact of irregular heterogeneous structures on the overall stability of projects.

[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 and soil 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 and soil 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:

[0008] 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;

[0009] S2. Establish a three-dimensional finite element model based on the actual site geometry, set the model boundary conditions, define the load conditions, and divide the unit grid, and associate the target parameters of the irregular heterogeneous structure with the field variables;

[0010] S3. Using database variable parameters, transfer target parameters of irregular heterogeneous structure;

[0011] S4. Selecting a number of sub-regions in the horizontal direction of the standard normal distribution probability density function as the delimiting conditions for the subsequent determination of the medium region to which the random base number belongs;

[0012] S5, generating a three-dimensional Gaussian random field;

[0013] S6. Rotate the Gaussian random field according to the actual exploration situation to characterize the inclination angle of the irregular heterogeneous structure in space;

[0014] S7. Use Gaussian random field correlation length to describe the relative length of irregular heterostructures in space;

[0015] S8. Determine the medium region where the Gaussian random value generated at the integration point is located. If the point is located in a different region, replace the random value at the point with a similar analytical physical quantity of the corresponding medium.

[0016] 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.

[0017] In S1, the geological structure data obtained by exploration are analyzed by big data, the data variation rules are mined, and the statistical characteristics database of physical and morphological parameters of irregular heterogeneous structures is formed. The database W={ c, l, t, α},in c represents the analytical physical quantity, l Indicates relative length, t Indicates relative thickness, α Indicates the relative inclination.

[0018] In S2, the steps for establishing a three-dimensional finite element model are:

[0019] 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 mesh 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 in the INP file, the target parameters of the irregular heterogeneous structure were associated with the field variables of the embedded subroutine USDFLD of the finite element analysis software ABAQUS.

[0020] In S3, secondary development is carried out based on the USDFLD interface of the finite element analysis software ABAQUS. 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.

[0021] 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.

[0022] 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:

[0023] (1);

[0024] 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 are the relevant lengths of the target parameters in the directions of the three coordinate axes.

[0025] 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:

[0026] (2);

[0027] In formula (2): Δ x, Δ y , Δ z Indicates the relative distance between any two points in the space before rotation in the directions of the three coordinate axes; 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;

[0028] Substitute formula (2) into formula (1), and Z The square exponential correlation function after axis rotation is expressed as:

[0029] (3);

[0030] In formula (3): is the rotated square exponential correlation function.

[0031] 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 irregular heterostructures in space.

[0032] In S8, the medium region where the Gaussian random value is located is determined. If the Gaussian random value generated at the integration point is within the defined area, then the point belongs to the heterogeneous structure area, 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, then the point belongs to the surrounding rock and soil area, and the random value of the point is replaced by the numerical value of the same type of physical quantity analyzed by the surrounding rock and soil.

[0033] 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 and soil stratum model containing irregular and complex heterogeneous structures.

[0034] The present invention has the following beneficial effects:

[0035] 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 and complex heterogeneous structures in space, effectively avoiding excessive assumptions in the analysis model that deviate from the actual engineering situation.

[0036] 2. The present invention can leverage the specific advantages of secondary development of subroutines to efficiently couple finite element meshes of arbitrary shapes with random fields, achieving a technological breakthrough in seamlessly connecting the target random response of irregular heterogeneous structures with the finite element three-dimensional model, saving a large amount of computing resources and time.

[0037] 3. The present invention can directly generate a three-dimensional stratum model containing irregular and 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.

[0038] 4. The concept of heterogeneous structure referred to in this 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 the three-dimensional model of irregular heterogeneous structures under complex geological conditions, and has good economic benefits and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 The present invention is a flow chart of a method for simulating a three-dimensional rock and soil stratum model containing irregular complex heterogeneous structures.

[0041] Figure 2 It is the model geometric size in the three-dimensional formation model of the embodiment of the present invention.

[0042] Figure 3 It is the corresponding finite element model in the three-dimensional formation model of the embodiment of the present invention.

[0043] Figure 4 Schematic diagram of the standard normal distribution probability density curve for defining the heterostructure region in the present invention.

[0044] Figure 5 The Gaussian random field of the present invention is Z Schematic diagram of the relevant lengths before and after axis rotation; Figure a represents the schematic diagram before rotation, and Figure b represents the schematic diagram after rotation.

[0045] 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°.

[0046] 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°.

[0047] 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

[0048] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0049] In practical engineering, irregular, complex, and heterogeneous structures are widespread within rock and soil strata, exhibiting high concealment and location uncertainty. Using efficient simulation methods to characterize their possible spatial configurations is crucial for effectively revealing the mechanisms of physical response within the strata. To this end, this paper further illustrates the proposed technical solution through the example of a rectangular stratum model containing irregular, complex, and heterogeneous structures.

[0050] 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:

[0051] 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.

[0052] Specifically, in S1, the geological structure data obtained by exploration are analyzed by big data, the data variation rules are mined, and a statistical characteristic database of physical and morphological parameters of irregular heterogeneous structures is formed. The database W={ c, l, t, α},in c represents the analytical physical quantity, l Indicates relative length, t Indicates relative thickness, α Indicates the relative inclination angle and sets the initial value.

[0053] 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.

[0054] Specifically, in S2, the steps of establishing a three-dimensional finite element model are:

[0055] 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 、 3As shown, a finite element model was created using an interactive interface. Basic material parameters were set. The bottom displacement boundary condition of the model was set to a fixed constraint, and the surrounding displacement boundary conditions were set to vertical constraints, meaning the normal displacement was zero but sliding was allowed along the surface. The top surface displacement boundary condition was set to a free boundary, and a vertical gravity load was applied. The model unit mesh was refined using the three-dimensional eight-node hexahedron C3D8R element type to ensure a smooth transition between the interface between the heterogeneous structure and the surrounding rock and soil. The finite element model was exported as an INP calculation source file. In the INP file, the strength parameters of the irregular heterogeneous structure were associated with the field variables of the ABAQUS embedded subroutine USDFLD, and the custom field variable SDV was set as the unit output field variable.

[0056] The specific contents of the modified statements in the INP file are as follows:

[0057] * MATERIALS

[0058] *Depvar

[0059] 1,

[0060] *Mohr Coulomb Hardening, dependencies=1

[0061] 1,0, 0 , 1

[0062] 20,0, 0 , 20

[0063] 100,0, 0, 100

[0064] 300,0,0, 300

[0065] *User Defined Field

[0066] * FIELD OUTPUT

[0067] *Element Output, directions=YES

[0068] SDV

[0069] Specifically, start ABAQUS / CAE: open the software and select the appropriate workspace;

[0070] 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.

[0071] Define material properties: Enter the Property module and define the required basic material parameters, such as elastic modulus, Poisson's ratio, etc.

[0072] 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.

[0073] Apply gravity load: Add a gravity load in the Load module, with the direction vertically downward.

[0074] S3. Use database variable parameters to transfer target parameters of irregular heterogeneous structures.

[0075] In S3, secondary development was conducted based on the ABAQUS embedded subroutine USDFLD interface. In the subroutine customization area, FORTRAN was used to write code for three modules: random field generation, morphology adjustment, and medium determination. Database variable parameters were fully utilized, and the target parameters of the irregular heterogeneous structure were indirectly transferred through the Gaussian random field to reasonably characterize the possible existing forms of the heterogeneous structure in space. The specific format of the subroutine USDFLD and the code writing partition are shown below:

[0076] 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)

[0077] INCLUDE 'ABA_PARAM.INC'

[0078] CHARACTER*80 CMNAME,ORNAME

[0079] CHARACTER*3FLGRAY(15)

[0080] DIMENSION FIELD(NFIELD),STATEV(NSTATV),DIRECT(3,3), T(3,3),TIME(2)

[0081] DIMENSION ARRAY(15),JARRAY(15),JMAC(*),JMATYP(*), COORD(*)

[0082] ! (The following is the user code customization area)

[0083] ! Random field generation code area

[0084] ! Irregular heterogeneous structure morphology setting area

[0085] ! Random Media Determination Area

[0086] RETURN

[0087] END

[0088] The whole process is decomposed into three key steps: Gaussian random field generation, morphology adjustment and medium determination.

[0089] S4. Select several sub-regions in the horizontal coordinate direction of the standard normal distribution probability density function as the boundary conditions for subsequent judgment of the medium region to which the random base belongs.

[0090] 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.

[0091] 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 and n They 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).

[0092] S5. Generate a three-dimensional Gaussian random field.

[0093] 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 advantage of being able to organically integrate with finite element meshes of arbitrary shapes and generating them efficiently. To this end, the present invention uses the modified linear estimation method to generate a three-dimensional Gaussian random field, and accordingly uses a squared exponential autocorrelation function to describe the spatial correlation of the parameters. Its mathematical expression is as follows:

[0094] (1);

[0095] 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 are the relevant lengths of the target parameters in the directions of the three coordinate axes.

[0096] S6. Rotate the Gaussian random field according to the actual exploration situation to characterize the inclination angle of the irregular heterogeneous structure in space.

[0097] 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 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, Z The axis rotates, and after the rotation, the relative distances of the three coordinate axes in formula (1) can be expressed as:

[0098] (2);

[0099] In formula (2): Δ x , Δ y , Δ z Indicates the relative distance between any two points in the space before rotation in the directions of the three coordinate axes; 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;

[0100] Substituting formula (2) into formula (1), the square exponential correlation function after rotation around the Z axis can be expressed as:

[0101] (3);

[0102] In formula (3): is the rotated square exponential correlation function.

[0103] S7. Use Gaussian random field correlation length to describe the relative length of irregular heterostructures in space.

[0104] 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 purpose, 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.

[0105] S8. Determine the medium region where the Gaussian random value generated at the integration point is located. If 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.

[0106] In S8, the medium region where the Gaussian random value is located is determined. If the Gaussian random value generated at the integration point is within the defined region, then 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 region, then 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 type of physical quantity analyzed by the surrounding rock and soil.

[0107] 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 Q If 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 considered to be 10 kPa. If the point is not within the defined area, it belongs to the surrounding rock and soil area, and similarly, 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 considered to be 40 kPa.

[0108] 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.

[0109] In S9, the USDFLD subroutine is called in the CAE interactive interface of 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 and soil stratum model containing irregular complex heterogeneous structures. Figures 6-8 shown.

[0110] from Figures 6-8 It can be seen that the technical method proposed in this invention can accurately characterize the existence of irregular and complex heterogeneous structures in a three-dimensional model. The interface between the two media is relatively smooth, and the spatial geometric characteristics of the heterogeneous structure are distinct. This example further demonstrates the uniqueness and effectiveness of the technical method proposed in this invention in efficiently simulating irregular and complex heterogeneous structures within formations.

[0111] The above embodiments are only used to illustrate the present invention, wherein the structure, connection mode and manufacturing process of each component can be changed. Any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the scope of protection 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 database of statistical characteristics of physical and morphological parameters of irregular heterogeneous structures is obtained; S2. Establish a three-dimensional finite element model based on the actual site geometry, set the model boundary conditions, define the load conditions, and divide the unit grid, and associate the target parameters of the irregular heterogeneous structure with the field variables; S3. Using database variable parameters, transfer target parameters of irregular heterogeneous structure; S4. Selecting a number of sub-regions in the horizontal direction of the standard normal distribution probability density function as the delimiting conditions for the subsequent determination of the medium region to which the random base number 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 heterostructures in space; S8. Determine the medium region where the Gaussian random value generated at the integration point is located. If the point is located in a different region, replace the random value at 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; In S1, the geological structure data obtained by exploration are analyzed by big data, the data variation rules are mined, and a statistical characteristic database of physical and morphological parameters of irregular heterogeneous structures is formed. The database W={ c, l, t, α },in c represents the analytical physical quantity, l Indicates relative length, t Indicates relative thickness, α Indicates relative inclination; In S2, the steps to establish a three-dimensional finite element model are: A three-dimensional finite element model was established. 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 top surface were set as free boundaries. A vertical gravity load was applied. The model element mesh was divided using the three-dimensional eight-node hexahedron C3D8R element type. The finite element model was exported as an INP calculation source file. In the INP file, the target parameters of the irregular heterogeneous structure were associated with the field variables of the USDFLD subroutine embedded in the finite element analysis software ABAQUS. In S3, secondary development is carried out based on the USDFLD interface of the finite element analysis software ABAQUS. The target parameters of the irregular heterogeneous structure are indirectly transferred through the Gaussian random field by using database variable parameters to characterize the morphology of the irregular heterogeneous structure in space. 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 determination 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. 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 are the relevant lengths of the target parameters in the three coordinate axis directions; 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; Respectively represent the relative distances between any two points in the space after rotation in the directions of the three coordinate axes; Substitute formula (2) into formula (1), and Z The square exponential correlation function after axis rotation is expressed as: （3） ； In formula (3): is the rotated square exponential correlation function.

2. 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 irregular heterostructures in space.

3. 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 integration point is within the defined area, then the point belongs to the heterogeneous structure area, 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, then the point belongs to the surrounding rock and soil area, and the random value of the point is replaced by the numerical value of the same type of physical quantity analyzed by the surrounding rock and soil.

4. 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 and soil stratum model containing irregular and complex heterogeneous structures.

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