Modeling method for reflecting real microstructure of layered rock

Abstract

The invention discloses a modeling method for reflecting a real microstructure of layered rock, which comprises the following steps of: acquiring lithofacies characteristics of the layered rock, constructing an initial layered rock model according to the lithofacies characteristics, and converting and correcting crystal grains in the initial layered rock model to obtain the layered rock model; different bonding modes are adopted for interfaces of different minerals in the layered rock model, and a bedding surface is generated; and according to the indoor macro and micro mechanical parameters of the layered rock, carrying out micro mechanical quantitative calibration on the layered rock model to obtain a finally calibrated layered rock model.

Description

Technical Field

[0001] This invention belongs to the field of rock modeling technology, and in particular relates to a modeling method that reflects the true microstructure of layered rocks. Background Technology

[0002] Existing modeling methods for layered rocks depict uniformly distributed, straight, and flat bedding planes, which resemble the structure of artificially manufactured rock-like materials but does not reflect the characteristics of natural rocks. In reality, under long-term geological tectonic activity, bedding planes exhibit complex surface morphologies and irregular distribution. Furthermore, while traditional grain modeling methods are widely used for homogeneous rocks, no method has yet been developed for modeling layered rocks beneath fractured grains. Laboratory experiments cannot study the failure behavior of layered rocks at the microscopic grain level. Therefore, the lack of relevant modeling methods restricts the study of the mechanical behavior of layered rocks at the microscopic level. Currently, there is a lack of an improved grain modeling method that reflects the true microstructure of layered rocks, thus hindering the effective modeling of layered rock models. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a modeling method that reflects the true microstructure of layered rocks, thereby resolving the issues present in the prior art.

[0004] To achieve the above objectives, the present invention provides a modeling method that reflects the true microstructure of layered rocks, comprising:

[0005] The lithofacies characteristics of the layered rock are obtained, an initial layered rock model is constructed based on the lithofacies characteristics, and the grains in the initial layered rock model are transformed and corrected to obtain the layered rock model.

[0006] Different bonding methods are used at the interfaces of different minerals in the layered rock model to generate bedding planes;

[0007] Based on the indoor macroscopic and microscopic mechanical parameters of the layered rock, the layered rock model is quantified and calibrated using microscopic mechanics to obtain the final calibrated layered rock model.

[0008] Optionally, the process of obtaining the lithofacies characteristics includes:

[0009] The petrographic features of layered rocks were detected by polarized light microscopy. These petrographic features included the types and original proportions of minerals in the layered rocks, the average aspect ratio and size of the grains, and each grain corresponding to a type of mineral.

[0010] Optionally, the process of constructing the initial layered rock model includes:

[0011] An initial layered rock model is constructed based on the types and proportions of minerals and the size of grains in the layered rock, wherein the bedding planes of the initial layered rock model are vertical.

[0012] Optionally, the process of transforming the grains in the initial layered rock model includes:

[0013] The grains in the initial layered rock model are adjusted based on the average aspect ratio of the grains. The area of ​​the grains in the initial layered rock model remains unchanged, but the lengths of the major and minor axes of the grains are adjusted according to the average aspect ratio of the grains.

[0014] Optionally, the process of correcting the transformed grains includes:

[0015] The converted grains in the initial layered rock model are judged based on the original proportions of the minerals. When the error between the proportion of the converted grains and the original proportions of the minerals exceeds the error threshold and the proportion of the converted grains is greater than the original proportions of the minerals, the current mineral type corresponding to the error threshold is determined. The size of a grain in the current mineral type is judged based on the size of grains in other mineral types. If the size of a grain in the current mineral type matches the size of grains in other mineral types, the corresponding grain is converted into a mineral type that matches the size.

[0016] When the error between the ratio of the converted grains and the ratio of the minerals exceeds the error threshold and the ratio of the converted grains is less than the original ratio of the minerals, the current mineral type corresponding to the error threshold is determined. The size of a grain in another mineral type is judged based on the size of the grain in the current mineral type. If the size of a grain in another mineral type matches the size of the grain in the current mineral type, the corresponding grain is converted into a mineral type that matches the size.

[0017] Iterate through all mineral types and calculate the converted proportion of each mineral until the error between the converted proportion of all mineral types and the original proportion is less than the error threshold.

[0018] Optionally, the generation process of the bedding plane includes:

[0019] In the layered rock model, the interfaces between different minerals are set as bedding planes, wherein the bedding planes are set as smooth joints and the interfaces between the same minerals are set as parallel joints.

[0020] Optionally, the process of performing micromechanical quantitative calibration on the layered rock model includes:

[0021] The micromechanical parameters of minerals in layered rocks are measured using nanoindentation technology. The micromechanical parameters are then adjusted according to the reduction factor to obtain the actual micromechanical parameters of the layered rock model.

[0022] Optionally, the process of performing micromechanical quantitative calibration on the layered rock model further includes:

[0023] The macroscopic uniaxial compressive strength of the layered rock was obtained by conducting uniaxial compression tests on the layered rock using a uniaxial compression testing machine.

[0024] The strength of the bedding planes in the layered rock model is adjusted until the strength of the layered rock model is the same as the macroscopic uniaxial compressive strength of the layered rock, thus obtaining the calibrated strength of the bedding planes in the layered rock model.

[0025] Optionally, the process of performing micromechanical quantitative calibration on the layered rock model further includes:

[0026] Uniaxial compression tests were conducted on layered rocks to obtain their elastic modulus. The stiffness of the bedding planes in the layered rock model was then calculated based on the elastic modulus of the layered rocks.

[0027] On the other hand, the present invention provides a modeling system that reflects the true microstructure of layered rocks for performing the above-described method.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] This invention provides a modeling method that reflects the true microstructure of layered rocks. Combining transformation and correction algorithms, it can construct a model that conforms to the actual grain shape; it can employ different bonding methods to address the differences between interfaces of the same mineral and interfaces of different minerals; it can construct uneven bedding planes that conform to the actual morphology based on the formation mechanism of bedding planes; and it can quantitatively calibrate the micromechanical parameters of the layered rock model according to laboratory macro- and micro-mechanical parameters. This invention achieves the goal of reproducing the mechanical behavior of layered rocks at the grain level by constructing a fractable numerical model that reflects the true microstructure of layered rocks. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0031] Figure 1 This is a layered rock model conforming to the initial grain size in an embodiment of the present invention;

[0032] Figure 2 This is a layered rock model that conforms to the actual mineral proportions and grain sizes in this embodiment of the invention;

[0033] Figure 3 This is a layered rock model that conforms to the actual grain shape in an embodiment of the present invention;

[0034] Figure 4 This is a layered rock model that conforms to the actual bedding plane morphology in an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the method flow according to an embodiment of the present invention. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0038] Regarding existing technologies, a paper titled "Developments to the Bonded Block Modeling Technique for Discrete Element Simulation of Transversely Isotropic Rocks" discloses a method for establishing a discrete element numerical model of layered rocks based on the grain method. However, the proposed model, in order to simulate realistic failure modes, directly embeds flat bedding planes as potential failure surfaces; and the grains cannot undergo internal fracture. Existing technologies suffer from problems such as rigid embedding within layers, not conforming to rock structure, and failing to consider internal fracture. In this invention, the bedding planes are not flat and are not directly embedded without basis. Instead, according to the actual layered rock structure, the bedding planes are defined as the interfaces between different minerals; simultaneously, the interior of the grains is fractureable.

[0039] The paper titled "Study on the Influence of Granite Mineral Grain Shape and Orientation on its Mechanical Properties Based on Grain Texture Model" also uses different bonding methods when defining grain boundaries. This existing technology also has the problem of modeling that does not conform to reality, and it does not address the issue of proportional correction for different minerals. This existing technology is only technically similar and is not used for modeling layered rocks. This invention can correct the mineral proportions for modeling layered rocks, making the layered rocks more consistent with reality.

[0040] This invention proposes a modeling method that reflects the true microstructure of layered rocks. Based on the traditional discrete element method for grain modeling, it combines transformation and correction algorithms to establish a model that conforms to the actual grain shape. Based on the actual macroscopic and microscopic mechanical parameters of layered rocks in the laboratory, the microscopic mechanical parameters of the numerical model are quantified and calibrated. Based on the generation mechanism of bedding planes, bedding planes that conform to the real morphology and have uneven surfaces are constructed. Through the fracture process of breakable grains, the mechanical behavior of layered rocks is restored from the grain level.

[0041] The model established in this invention reconstructs the transgranular fracturing and grain boundary fracturing behavior of layered rocks, overcoming the limitation of laboratory experiments in analyzing the damage and failure process of layered rocks at the grain level, and clarifying the failure mechanism of layered rocks from a microscopic perspective. Furthermore, due to the widespread distribution of layered rocks in actual geology, such as shale, coal, sandstone, and gneiss, the established model can be used for relevant engineering verification and analysis. By collecting actual layered rocks and modeling them, forces can be applied to the model in relevant scenarios or other simulation methods to simulate the failure state of layered rocks under corresponding scenarios, providing effective guidance for practical work, such as simulating the shale gas extraction process, the coal mining fracturing process, and the stability issues of tunnels traversing layered rocks.

[0042] This invention provides a modeling method that reflects the true microstructure of layered rocks, comprising the following steps:

[0043] Based on the results of indoor analysis using polarizing microscopes, conversion algorithms, and correction algorithms, a layered rock model conforming to the actual grain shape was established. In this model, different bonding methods were used at the interfaces of the same mineral and those of different minerals to distinguish their properties. Based on the formation mechanism of bedding planes, uneven bedding planes conforming to the actual morphology were constructed. Based on the macroscopic and microscopic mechanical parameters of the layered rock model obtained from the indoor analysis, the microscopic mechanical parameters of the model were quantitatively calibrated.

[0044] The methods for quantifying and calibrating the microscopic parameters of the model include: calibrating the elastic modulus and strength of the rock matrix in the model based on indoor nanoindentation data and using damage mechanics principles; calibrating the strength of the bedding planes in the model based on the macroscopic uniaxial compressive strength of layered rocks in the laboratory; and calibrating the stiffness of the bedding planes in the model based on the macroscopic Young's modulus of layered rocks in the laboratory.

[0045] This invention provides a modeling method that reflects the true microstructure of layered rocks. Combining transformation and correction algorithms, it can construct a model that conforms to the actual grain shape; it can employ different bonding methods to address the differences between interfaces of the same mineral and interfaces of different minerals; it can construct uneven bedding planes that conform to the actual morphology based on the formation mechanism of bedding planes; and it can quantitatively calibrate the micromechanical parameters of the layered rock model according to laboratory macro- and micro-mechanical parameters. This application achieves the goal of reproducing the mechanical behavior of layered rocks at the grain level by constructing a fractable numerical model that reflects the true microstructure of layered rocks.

[0046] Referring to the relevant accompanying figures, such as Figure 5 As shown, the above technical solution will be described in detail:

[0047] Step 1: Determine the petrographic characteristics of mineral grains in layered rocks:

[0048] The microstructure of layered rocks was observed using a polarizing microscope to determine the types and proportions of constituent minerals. Simultaneously, due to long-term geological tectonic activity, the mineral grains in the layered rocks exhibit elongated shapes. The average ratio of the long axis to the short axis of the grains (average aspect ratio) and the size range of different mineral grains were measured. The lithofacies characteristics include the aforementioned types and proportions of minerals, as well as the average aspect ratio and size range of mineral grains.

[0049] For example, observation and measurement using a polarizing microscope revealed that a certain gneiss schist was composed of 60% quartz, 35% biotite, and 5% other minerals. The average aspect ratio of the mineral grains was 2:1. The size of the quartz grains was 1mm-3mm, the size of the biotite grains was 0.7-2.5mm, and the size of the other minerals was 0.5-2mm.

[0050] Step 2: Construct a layered rock model that conforms to the actual grain size:

[0051] Based on the petrographic characteristics measured in step one, 92% quartz grains and 8% other minerals were randomly generated in the discrete element method. The mineral sizes conformed to the actual mineral size range, such as... Figure 1 As shown. Then, grains within the three vertical ranges that meet the biotite size criteria are redefined as biotite, and the proportion of biotite is calculated after each grain is redefined, until the biotite proportion reaches 35%. Subsequently, the proportions of other minerals are corrected, and those meeting the quartz size criteria are redefined as quartz, and the proportion of quartz minerals is calculated after each other mineral grain is redefined, until the quartz proportion reaches 60%. A layered rock model that satisfies the actual mineral proportions and grain sizes is constructed, as shown. Figure 2As shown, the composition is 60% quartz, 35% biotite, and 5% other minerals. Quartz and biotite are distributed in layers with perpendicular bedding planes. Each small, irregular blocky structure represents a grain, and their combination forms a layered rock model.

[0052] Step 3: Construct a layered rock model that conforms to the actual grain shape using conversion algorithms and correction procedures:

[0053] In step two, the grains only meet the proportions and initial dimensions, but their specific shapes are not adjusted. The average aspect ratio of the model grains in step two is 1:1, which does not conform to the slender characteristics of actual grains. A transformation algorithm is used to change the shape of the mineral grains.

[0054] Taking a spherical initial grain as an example, the conversion algorithm formula is as follows:

[0055]

[0056] In the formula, S is the area of ​​the grain, which remains unchanged before and after the transformation. a and b are the initial major and minor axes of the grain, respectively, and a' and b' are the major and minor axes of the grain after the transformation, respectively. λ is the average aspect ratio of the grain. For a certain layered gneiss, λ = 2, we can get a' = 1.41a and b' = b / 1.41.

[0057] However, after shape conversion, some minerals may extend beyond the model, causing changes in the proportions of different minerals within the model. Therefore, the ratio of quartz to biotite needs to be corrected. The correction method is as follows (taking quartz as an example):

[0058] ① Write a program to calculate the proportion of quartz minerals and determine whether the error between the quartz proportion and the actual quartz mineral proportion is less than the error threshold. An example error threshold is 3%.

[0059] The program is written in the fish language. First, the total area S of all minerals is determined. all With the area S of quartz mineral shi The area of ​​the suitable mineral is then divided by the area of ​​all minerals to obtain the quartz mineral ratio r. shi r shi Subtract the actual quartz mineral ratio of 60% and determine whether the absolute value is less than the error threshold of 3%.

[0060] ② If the quartz proportion is greater than the actual mineral proportion and the error exceeds 3%, select a quartz mineral, write a program to determine if it matches the size of biotite. If it matches, convert it to biotite and calculate the quartz proportion at this time; if it does not match, find the next quartz mineral. Repeat this operation until the error between the quartz proportion and the actual proportion is less than the error threshold of 3%.

[0061] The program mentioned is written in the fish language, and the data flow of the program execution is as follows: when the quartz ratio r shi If the proportion of quartz minerals is greater than 63% of the actual proportion (i.e., the quartz proportion is greater than 60% of the actual quartz mineral proportion) and the error is greater than the error threshold of 3%, select a quartz mineral and determine whether its size is within the biotite range (0.7-2.5 mm). If the size is within this range, the mineral is redefined as a biotite mineral. Then, compare the quartz mineral proportion r again. shi， If the difference from 60% is within 3%, the quartz mineral ratio is considered to meet the requirements, and the process switches to judging the biotite mineral ratio. If the difference is still more than 3%, the redefinition procedure is repeated until the quartz mineral ratio meets the requirements.

[0062] ③ If the quartz proportion is less than the actual mineral proportion and the error exceeds 3%, i.e., the quartz proportion is less than 60% of the actual quartz mineral proportion and the error is greater than the error threshold of 3%, select a biotite mineral and determine whether it conforms to the quartz size. If it does, convert it to quartz and calculate the quartz proportion at this time; if it does not, find the next biotite mineral. Repeat this operation until the error between the quartz proportion and the actual proportion is less than 3%.

[0063] Biotite and other minerals also underwent calibration procedures sequentially. After completing the conversion algorithm and calibration procedures, a layered rock model that conforms to the actual grain shape can be constructed, such as... Figure 3 As shown.

[0064] The program mentioned is written in the fish language, and the biotite ratio correction program is the same as that for quartz minerals.

[0065] Step 4: Construct uneven, textured layers that match the actual shape:

[0066] Parallel bonding is widely used to simulate the behavior of rock materials, while smooth joint bonding is used to characterize the behavior of bedding planes. In other methods of constructing layered rock models, a straight line is directly embedded in the model as a flat bedding plane. However, in reality, bedding planes are the interfaces between different minerals, and their morphology is uneven. Therefore, in this method, the interfaces between different minerals are defined as bedding planes. Figure 4 As shown, the resulting bedding planes are uneven, realistically reproducing the actual morphology of the bedding planes. The bedding planes are set as smooth joints, while other bonding structures, i.e., the interfaces of the same minerals, are set as parallel bonding.

[0067] Specifically, the interfaces between different mineral grains are set as smooth joint models to represent bedding planes, while the interfaces and interiors of the same minerals are set as parallel bonding models to represent layered rock matrix.

[0068] Step 5: Quantitatively calibrate the micromechanical parameters of the model:

[0069] The micromechanical parameters of discrete element models need to be calibrated. Grain models have numerous micromechanical parameters, including internal parameters of different mineral grains, parameters of intermineral bonding, and parameters of bedding planes. Therefore, it is crucial to construct micromechanical parameters that reflect the true mechanical characteristics of layered rocks. This invention quantifies and calibrates the micromechanical parameters of minerals in the model based on nanoindentation experiments and damage mechanics mechanisms.

[0070] The specific quantitative calibration steps are as follows:

[0071] ① The micromechanical parameters of different minerals are first measured using nanoindentation technology. For example, the microelastic modulus and hardness of quartz, biotite and other minerals in a layered gneiss are measured using nanoindentation.

[0072] ② Nanoindentation measures the micromechanical parameters of locally intact regions within the grains. Due to the presence of micro-damage within the rock, the actual micro-elastic modulus and hardness of the mineral are reduced. Based on the concept of damage mechanics, the actual micro-elastic modulus within the mineral grains in the model is determined as follows:

[0073] E 微-实际 =η·E 纳米 (2)

[0074] In the formula, E 微-实际 E represents the actual calibrated microelastic modulus of the mineral. 纳米 η is the microscopic elastic modulus measured by nanoindentation, and η is the elastic modulus reduction factor due to micro-damage inside the rock.

[0075] Regarding the process of obtaining the elastic modulus reduction factor: Since layered rocks with perpendicular bedding planes have the highest elastic modulus and are least affected by bedding planes, they best reflect the degree of influence of microscopic damage on bedding planes. Therefore, the value of η is adjusted until the model of layered rocks with perpendicular bedding planes matches the macroscopic elastic modulus of actual layered rocks with perpendicular bedding planes. The specific steps are as follows: First, a uniaxial compression test is conducted to determine the macroscopic elastic modulus E of layered rocks with perpendicular bedding planes. 实验-垂直 Subsequently, η = 0.5 was used to calibrate the microscopic parameters of the elastic modulus of the discrete element, and the macroscopic elastic modulus E of the rock model at this time was obtained. 模型-垂直 Compared to E 实验-垂直 and E 模型-垂直 If E 实验-垂直 Value exceeds E 模型-垂直 If the value is above 5%, η increases by 20%; if E 实验-垂直 Value less than E 模型-垂直 If the value is above 5%, η decreases by 20%. Measure E after adjusting η. 模型-垂直 Until it is with E 实验-垂直 If the difference is within 5%, then η at this point is taken as the final elastic modulus reduction factor.

[0076] Since the hardness and strength of rocks are linearly proportional, the actual microscopic strength parameters of mineral grains in the model are defined as follows:

[0077] σ 微-实际 =η2·k·H 纳米 (3)

[0078] In the formula, σ 微-实际 The actual calibrated mineral micro-strength, η2 is the strength reduction factor due to micro-damage within the rock, k is the ratio of hardness to strength, and H 纳米 Microhardness measured by nanoindentation.

[0079] Regarding the process of obtaining the strength reduction factor η2 and the hardness-strength ratio k: Since layered rocks with horizontal bedding planes have the highest strength and are least affected by bedding planes, they best reflect the degree of influence of micro-damage on strength. Therefore, the value of η2·k is adjusted until the model matches the actual strength of layered rocks with horizontal bedding planes. The specific steps are as follows: First, a uniaxial compression test is conducted to determine the strength σ of layered rocks with horizontal bedding planes. 实验-水平 Subsequently, the strength-related micro-parameters of the discrete element were calibrated using η²·k = 0.5, and the strength σ of the rock model at this point was obtained. 模型-水平 Comparison with σ 实验-水平 and σ 模型-水平 If σ 实验-水平 Value exceeding σ 模型-水平 If the value is above 5%, η²·k increases by 10%; if σ 实验-水平 Value less than σ 模型-水平 For values ​​above 5%, η²·k decreases by 10%. Measure σ after adjusting η²·k. 模型-水平 until it is related to σ 实验-水平 If the difference is within 5%, then η2·k at this point is taken as the final elastic modulus reduction factor.

[0080] ③ The strength of bedding planes in the macroscopic uniaxial compressive strength calibration model of layered rocks in the laboratory.

[0081] Uniaxial compression tests were conducted on layered rocks using a uniaxial compression testing machine to measure the macroscopic uniaxial compressive strength of the layered rocks. Since the bedding strength of layered rocks with perpendicular bedding planes significantly affects the final rock strength, the strength of the bedding planes was adjusted until the model strength matched the actual strength, thus determining the strength of the bedding planes in the model.

[0082] ④ Stiffness of bedding planes in the macroscopic Young's modulus calibration model based on indoor layered rocks.

[0083] In a uniaxial compression test, the elastic modulus of layered rock can be measured. Based on this, the stiffness of the bedding planes in the model can be calculated using the following formula:

[0084]

[0085] In the formula, k 刚 E represents the stiffness of the bedding plane. 水平 E represents the elastic modulus of horizontally bedding rock. 垂直 δ represents the elastic modulus of rock perpendicular to the bedding planes, and δ represents the spacing between the bedding planes.

[0086] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A modeling method that reflects the true microstructure of layered rocks, characterized in that, include: The lithofacies characteristics of the layered rock are obtained, an initial layered rock model is constructed based on the lithofacies characteristics, and the grains in the initial layered rock model are transformed and corrected to obtain the layered rock model. Different bonding methods are used at the interfaces of different minerals in the layered rock model to generate bedding planes; Based on the indoor macroscopic and microscopic mechanical parameters of the layered rock, the layered rock model is quantified and calibrated using microscopic mechanics to obtain the final calibrated layered rock model.

2. The method according to claim 1, characterized in that, The process of obtaining the lithofacies characteristics includes: The petrographic features of layered rocks were detected by polarized light microscopy. These petrographic features included the types and original proportions of minerals in the layered rocks, the average aspect ratio and size of the grains, and each grain corresponding to a type of mineral.

3. The method according to claim 2, characterized in that, The process of constructing the initial layered rock model includes: An initial layered rock model is constructed based on the types and proportions of minerals and the size of grains in the layered rock, wherein the bedding planes of the initial layered rock model are vertical.

4. The method according to claim 1, characterized in that, The process of transforming the grains in the initial layered rock model includes: The grains in the initial layered rock model are adjusted based on the average aspect ratio of the grains. The area of ​​the grains in the initial layered rock model remains unchanged, but the lengths of the major and minor axes of the grains are adjusted according to the average aspect ratio of the grains.

5. The method according to claim 1, characterized in that, The process of correcting the converted grains includes: The converted grains in the initial layered rock model are judged based on the original proportions of the minerals. When the error between the proportion of the converted grains and the original proportions of the minerals exceeds the error threshold and the proportion of the converted grains is greater than the original proportions of the minerals, the current mineral type corresponding to the error threshold is determined. The size of a grain in the current mineral type is judged based on the size of grains in other mineral types. If the size of a grain in the current mineral type matches the size of grains in other mineral types, the corresponding grain is converted into a mineral type that matches the size. When the error between the ratio of the converted grains and the ratio of the minerals exceeds the error threshold and the ratio of the converted grains is less than the original ratio of the minerals, the current mineral type corresponding to the error threshold is determined. The size of a grain in another mineral type is judged based on the size of the grain in the current mineral type. If the size of a grain in another mineral type matches the size of the grain in the current mineral type, the corresponding grain is converted into a mineral type that matches the size. Iterate through all mineral types and calculate the converted proportion of each mineral until the error between the converted proportion of all mineral types and the original proportion is less than the error threshold.

6. The method according to claim 1, characterized in that, The generation process of the bedding planes includes: In the layered rock model, the interfaces between different minerals are set as bedding planes, wherein the bedding planes are set as smooth joints and the interfaces between the same minerals are set as parallel joints.

7. The method according to claim 1, characterized in that, The process of performing micromechanical quantitative calibration on the layered rock model includes: The micromechanical parameters of minerals in layered rocks are measured using nanoindentation technology. The micromechanical parameters are then adjusted according to the reduction factor to obtain the actual micromechanical parameters of the layered rock model.

8. The method according to claim 1, characterized in that, The process of performing micromechanical quantitative calibration on the layered rock model also includes: The macroscopic uniaxial compressive strength of the layered rock was obtained by conducting uniaxial compression tests on the layered rock using a uniaxial compression testing machine. The strength of the bedding planes in the layered rock model is adjusted until the strength of the layered rock model is the same as the macroscopic uniaxial compressive strength of the layered rock, thus obtaining the calibrated strength of the bedding planes in the layered rock model.

9. The method according to claim 1, characterized in that, The process of performing micromechanical quantitative calibration on the layered rock model also includes: Uniaxial compression tests were conducted on layered rocks to obtain their elastic modulus. The stiffness of the bedding planes in the layered rock model was then calculated based on the elastic modulus of the layered rocks.

10. A modeling system that reflects the true microstructure of layered rocks, characterized in that, Used to perform the method described in any one of claims 1-9.

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