Compensation method and device for incomplete similarity of discontinuous fractured rock mass model test

Abstract

The application provides a compensation method and device for an incomplete similarity of a discontinuous fissure rock mass model test, and belongs to the technical field of geomechanical model tests. The method comprises the following steps: determining a compensation formula of the discontinuous fissure rock mass model according to a model type of the discontinuous fissure rock mass model; obtaining a distortion parameter of a compensation pi term according to the compensation formula of the discontinuous fissure rock mass model and a pi term distortion occurring in a discontinuous fissure rock mass model test process; and generating a compensation model of the discontinuous fissure rock mass model according to the distortion parameter. The application can make the compensated model better represent the prototype.

Description

Technical Field

[0001] This application relates to the field of geomechanical model testing technology, and in particular to a compensation method and apparatus for incomplete similarity in discontinuous fractured rock mass model tests. Background Technology

[0002] In recent years, the development and utilization of deep earth space, as well as the extraction and storage of underground resources and energy, have become important directions for scientific and technological development. Examples include the construction of deep-buried tunnel complexes and the Jinping Underground Laboratory, geological disposal of high-level radioactive waste, geological carbon dioxide sequestration, and the development and utilization of medium-deep geothermal resources. Due to the extreme nature of the deep earth environment, the complexity of multi-field coupling, and the discontinuity of the storage medium, basic theoretical research on deep earth engineering usually lags behind its engineering activities, resulting in a certain degree of blindness, inefficiency, and uncertainty in engineering activities such as the development and utilization of deep earth space and the extraction and storage of deep earth resources and energy.

[0003] Currently, conducting three-dimensional physical model tests on underground engineering projects under complex geological conditions remains one of the important directions in rock engineering research. The main research content of physical model tests in rock engineering is geomechanical model testing. Among these, the selection of similar materials and the determination of relevant parameters based on the physical and mechanical properties of the prototype are key factors in geomechanical model testing, directly affecting the accuracy of the tests. The most widely used similarity criterion in geomechanical model testing is the similarity criterion determined based on the differential equations of continuum mechanics.

[0004] However, due to limitations in materials, processes, technology, and experimental environments, it is difficult to apply similarity criteria based on the differential equations of continuum mechanics to discontinuous structural surfaces such as faults and fracture zones, as these surfaces have very thin interlayers or low deformation moduli. Furthermore, deep-earth fractured rock masses exhibit prominent discontinuous characteristics, making existing geomechanical model tests inadequate for characterizing prototypes of discontinuous rock masses, resulting in poor accuracy in these tests. Summary of the Invention

[0005] This application provides a compensation method and apparatus for discontinuous fractured rock mass model tests that are not completely similar, in order to solve the problem that existing geomechanical model tests are difficult to characterize the prototype of rock masses with discontinuous characteristics and have poor model test accuracy.

[0006] In a first aspect, embodiments of this application provide a compensation method for incomplete similarity in discontinuous fractured rock mass model tests, including:

[0007] Based on the model type of the discontinuous fractured rock mass model, determine the compensation formula for the discontinuous fractured rock mass model.

[0008] Based on the compensation formula of the discontinuous fractured rock mass model and the π-term distortion that occurred during the discontinuous fractured rock mass model test, the distortion parameters of the compensation π-term were obtained.

[0009] A compensation model for the discontinuous fractured rock mass model is generated based on the distortion parameters.

[0010] Secondly, embodiments of this application provide a compensation device for incomplete similarity in discontinuous fractured rock mass model tests, comprising:

[0011] The compensation formula determination module is used to determine the compensation formula for the discontinuous fractured rock mass model based on the model type of the discontinuous fractured rock mass model.

[0012] The distortion parameter calculation module is used to obtain the distortion parameters of the π term to compensate for the distortion of the discontinuous fracture rock mass model based on the compensation formula of the discontinuous fracture rock mass model and the π term distortion that occurs during the discontinuous fracture rock mass model test.

[0013] The compensation model generation module is used to generate a compensation model for a discontinuous fractured rock mass model based on distortion parameters.

[0014] This application provides a compensation method and apparatus for incomplete similarity in discontinuous fractured rock mass model tests. First, a compensation formula for the discontinuous fractured rock mass model is determined based on its model type. Then, based on the compensation formula and the π-term distortion occurring during the model test, distortion parameters for the π-term are obtained. Finally, a compensated model of the discontinuous fractured rock mass model is generated based on these distortion parameters. Thus, by studying the influence of distortion on the model according to various similarity criteria, a compensation method for incompletely similar fractured rock mass models is proposed, enabling the compensated model to better represent the prototype. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram illustrating the principle of a distortion model provided in an embodiment of this application;

[0017] Figure 2 This is a flowchart illustrating the implementation of a compensation method for incomplete similarity in discontinuous fractured rock mass model tests provided in this application embodiment;

[0018] Figure 3 This is a schematic diagram of a single-crack model provided in an embodiment of this application;

[0019] Figure 4 This is a schematic diagram of a fracture network model provided in an embodiment of this application;

[0020] Figure 5 This is a schematic diagram of an underground chamber model provided in an embodiment of this application;

[0021] Figure 6 This is a schematic diagram showing the relationship between the π-term distortion ratio of a fractured rock mass underground chamber model and the normal displacement distortion ratio of the model monitoring points, provided in an embodiment of this application.

[0022] Figure 7 This is a diagram showing the relationship between the π5 and π6 distortion ratios under the extreme failure state of a model, as provided in an embodiment of this application.

[0023] Figure 8 This is a schematic diagram comparing the displacement cloud maps of a completely similar model and a distortion compensation model provided in an embodiment of this application. Detailed Implementation

[0024] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0026] As described in related technologies, existing geomechanical model tests are difficult to characterize the prototype of rock masses with discontinuous characteristics, resulting in poor accuracy of model tests.

[0027] To address the problems in the prior art, this application provides a method and apparatus for compensating for incomplete similarity in discontinuous fractured rock mass model tests. The method for compensating for incomplete similarity in discontinuous fractured rock mass model tests provided in this application is described below.

[0028] First, the research approach of this application will be introduced.

[0029] This application derives the similarity relationships for fully similar model tests of fractured rock masses. Based on these relationships, it analyzes the influence of distortions in various similarity criteria on the model when fractured rock masses exhibit incomplete similarity. Thus, by studying the impact of distortions in various similarity criteria on the model, a compensation method for incompletely similar fractured rock mass models is proposed, enabling the compensated model to better represent the prototype.

[0030] The following section provides a detailed analysis and introduction to similarity criteria and incomplete similarity.

[0031] In similarity studies, due to the discontinuity of fractured rock masses under complex conditions and the incomplete fundamental theory of deep-earth engineering, using equations to analyze the similarity relationships of fractured rock masses in deep-earth environments can complicate the problem. Dimensional analysis, however, is not limited to the mathematical theory of known equations and has certain advantages in dealing with complex physical phenomena whose mechanisms are not yet clear and whose laws are not fully understood. Therefore, this application uses dimensional analysis to determine the similarity relationships of fractured rock masses, and a series of dimensionless terms can be obtained using Buckingham's π theorem.

[0032] The physical quantities that affect the structural performance in fractured rock masses are as follows:

[0033] L (size), ρ (density), g (gravity coefficient), c (joint cohesion), φ (joint internal friction angle), E (elastic modulus of the rock matrix), μ (Poisson's ratio of the rock matrix), K n Normal stiffness of joints, K s Tangential stiffness of joints, σ ​​rock mass matrix stress, σ f Rock mass fracture stress, ε rock mass matrix strain, ε f Rock mass fracture strain, u (rock mass matrix displacement), t (time), P (external load), d (fracture width). In a mass system, the dimensions of these quantities are expressed using fundamental dimensions:

[0034]

[0035] The number of physical quantities n = 17, and the number of fundamental dimensions k = 3 in the mass system, i.e., the dimensions of mass M, length L, and time T are the fundamental dimensions, and the number of dimensionless quantities m = 4. Therefore, the number of similarity criteria that can be established is n - k = 14 (including 4 independent similarity criteria composed of dimensionless physical quantities). L, ρ, and g are selected as the fundamental physical quantities, and the dimensional matrices are shown in Table 1.

[0036]

[0037] Based on dimensional matrices and the principle of dimensional harmony, 14 similarity criteria can be derived:

[0038]

[0039] When π p =π m At that time, the fractured rock mass model is completely similar, and the model can represent the prototype. The similarity ratios of each parameter are defined as follows:

[0040]

[0041] Based on the above similarity criteria, the similarity relationships of various parameters of the fractured rock mass can be obtained as shown in Table 2.

[0042]

[0043] According to the definition of an incompletely similar model, or a distorted model, based on similarity theory, the incomplete similarity of a fractured rock mass mechanics model is due to the non-satisfaction of some π terms during model design. Therefore, the study of the influencing factors of incomplete similarity in fractured rock mass mechanics models is essentially a study of the impact of π term distortion on the model.

[0044] Similarity theory dimensional analysis can accurately obtain all π terms of the model, when π p =π m1 When p is the prototype and m1 is the similar model, it is a completely similar model, meaning the model does not produce distortion. When π p ≠π m1 When p is the prototype and m is the model, the models are not perfectly similar, meaning the models are distorted. In this case, a distortion coefficient δ is introduced. π π p =π m2 (m2 represents the distortion model) to indicate the degree of distortion in the π term. The distortion coefficients of each physical parameter in the model are represented by δ. △ m1 △ =m2 △ Let δ represent the degree of distortion of each parameter in the distortion model, and Δ represent the physical parameters of the model. The principle of the distortion model is as follows: Figure 1 As shown.

[0045] Based on the above analysis, a compensation method for incomplete similarity models of fractured rock masses is proposed, which mainly consists of two steps: 1) determining the influencing factors of incomplete similarity in mechanical model tests of fractured rock masses; 2) establishing a compensation method based on mechanical model tests of fractured rock masses.

[0046] Specifically, since fractured rock mass model tests are influenced by various factors, and different factors have different adaptability conditions for different models, specific compensation methods are proposed for different types of fractured rock mass model tests that are not entirely similar. These methods are: compensation methods for single-fracture models, compensation methods for fracture network models, and compensation methods for underground chamber excavation models. For single-fracture and fracture network models, fractures with width are treated as a type of filling material, and the average normal displacement of the model is used as the compensation condition. For the underground chamber excavation model, the damage condition of the top structural surface of the chamber and the displacement of the monitoring point at the top of the tunnel are used as compensation conditions.

[0047] See Figure 2 The document illustrates a flowchart of the compensation method for incomplete similarity in discontinuous fractured rock mass model tests provided in this application embodiment, detailed below:

[0048] Step 210: Determine the compensation formula for the discontinuous fractured rock mass model based on the model type of the discontinuous fractured rock mass model.

[0049] In some embodiments, the discontinuous fractured rock mass model can be categorized into single-fracture models, fracture network models, and underground chamber models. The underground chamber model is further divided into models stable after excavation and underground chamber models that fail after excavation. Different types of discontinuous fractured rock mass models correspond to different compensation formulas.

[0050] Step 220: Based on the compensation formula of the discontinuous fractured rock mass model and the π-term distortion that occurs during the discontinuous fractured rock mass model test, obtain the distortion parameters of the compensation π-term.

[0051] In some embodiments, π terms that do not satisfy the perfect similarity relationship during discontinuous fractured rock mass model tests can be identified as π-term distortions. Then, the distortion ratio of the π-term distortions is substituted into the compensation formula, and at least one π term is selected to calculate the distortion ratio of the compensated π-term, thus obtaining the distortion parameters of the compensated π-terms.

[0052] Step 230: Generate a compensation model for the discontinuous fractured rock mass model based on the distortion parameters.

[0053] In some embodiments, the model parameters can be modified first to compensate for the distortion ratio of the π term. If the normal displacement distortion ratio of the model is within a preset range, the model at this time is determined as the compensation model for the discontinuous fractured rock mass model. If the normal displacement distortion ratio of the model is not within the preset range, the process of "selecting at least one π term to compensate for the distortion ratio of the π term, modifying the model parameters to compensate for the distortion ratio of the π term" is repeated until the normal displacement distortion ratio of the model is within the preset range, and the model at this time is determined as the compensation model for the discontinuous fractured rock mass model.

[0054] The following section details the compensation methods for different types of discontinuous fractured rock mass models and provides verification examples.

[0055] 1. Compensation method and verification for incomplete similarity of single-crack models.

[0056] 1.1 Compensation Method for Incomplete Similarity in Single-Crack Models

[0057] The single-crack model simulation experiment used a plane strain cracked thin plate model under uniaxial compression. The prototype was granite, and the material was assigned elastic modulus E, Poisson's ratio μ, and density ρ. The crack infill material was assigned elastic modulus E. f Poisson's ratio μ f Density ρ f .like Figure 3As shown, the model adopts a non-through crack model, and the parameters of the prototype and the fully similar model are shown in Table 3.

[0058]

[0059] The physical quantities that affect the structural performance in a single-crack mechanical model are known to be: side length L, matrix elastic modulus E, matrix Poisson's ratio μ, matrix density ρ, crack width d, and crack infill elastic modulus E. f Poisson's ratio μ f Density ρ f And external load P.

[0060] Different similarity criteria can be obtained by selecting different fundamental physical quantities based on the conditions of the fundamental physical quantities. Using ρ, g, and L as fundamental physical quantities makes it simpler and more convenient to study the influencing factors, compensation, and correction methods of incomplete model similarity. Based on this, this application uses ρ, g, and L as fundamental physical quantities. Seven similarity criteria can be obtained using ρ, g, and L as fundamental physical quantities, as shown in the following formulas:

[0061] (1)

[0062] To analyze the influencing factors of incomplete similarity in the single-fracture mechanical model of fractured rock mass, it is necessary to consider the impact of distortion of the above seven similarity criteria on the model. Assuming that all similarity criteria are distorted, it can be expressed as:

[0063]

[0064] (2)

[0065] From (2), it can be seen that the distortion coefficient of the similarity criterion is affected by the similarity ratio of the model parameters. Since the change in the similarity ratio of the model parameters does not affect the model when the distortion coefficient of the similarity criterion remains unchanged, the equation of the similarity criterion can be simplified. During the physical model test, the size and gravitational acceleration of the model can be controlled to prevent distortion. Therefore, the size distortion ratio δL and the gravitational acceleration distortion ratio δg are considered to be 1. Since the influence of the π-term distortion on the model is fixed, it can be assumed that the density does not distort. Thus, the distortion equations of each π-term are simplified as follows:

[0066]

[0067] (3)

[0068] Therefore, the distortion of the seven similarity criteria π terms derived from the basic physical quantities ρ, g, and L can be regarded as a single-factor distortion of seven physical parameters, namely, elastic modulus E, crack width d, Poisson's ratio μ, and elastic modulus E of the crack filler. f Poisson's ratio μf Density ρ f The distortion of the external load P.

[0069] Currently, in rock mass engineering physical model tests, scholars typically focus on observing the strain and failure characteristics during the model experiment. Therefore, this application aims to evaluate the quasi-similarity between a partially similar model and the prototype by comparing the ratio of the average normal displacement of the partially similar model to that of a fully similar model after compensation and correction.

[0070] When studying the influencing factors of the incomplete similarity of the single-fracture mechanical model of fractured rock mass, the influence of the distortion of the single-factor physical parameters on the average normal displacement of the model is first analyzed theoretically. Specifically, according to the normal strain formula (4) in the isotropic linear elastic constitutive relation of rock, the normal strain of the model under isotropic conditions is inversely proportional to the elastic modulus of the model and linearly related to the Poisson's ratio and normal stress of the model. In this regard, after treating the fracture as a low-density, low-elastic-modulus filling material, the normal strain formula of the fracture can be written as formula (5), the normal strain of the fracture is inversely proportional to the elastic modulus of the fracture filling material and linearly related to the Poisson's ratio and normal stress of the model.

[0071] (4)

[0072] (5)

[0073] Based on formulas (4) and (5), it can be seen that the distortions of the elastic modulus of the rock and the elastic modulus of the fracture filler have an inverse relationship with the normal strain; the distortions of the Poisson's ratio of the rock and the Poisson's ratio of the fracture filler have a linear relationship with the normal strain. Therefore, it can be assumed that the influence of the distortions of the elastic modulus of the rock, the elastic modulus of the fracture filler, the Poisson's ratio of the rock, and the Poisson's ratio of the fracture filler on the overall average normal displacement distortion of the model remains unchanged in the anisotropic fractured rock mass model composed of rock and fractures. Based on the definition of distortion ratio of single-factor physical parameters, it can be assumed that the relationship between the distortion ratio of elastic modulus, the distortion ratio of Poisson's ratio, the distortion ratio of elastic modulus of crack filler and the distortion ratio of Poisson's ratio of crack filler and the distortion ratio of average normal displacement should be the same as the relationship between elastic modulus, Poisson's ratio, elastic modulus of crack filler and Poisson's ratio of crack filler and strain in formulas (4) and (5), which can be expressed as formulas (6) and (7).

[0074] (6)

[0075] (7)

[0076] The normal stress distortion ratio and the average normal displacement distortion ratio of the single-crack mechanical model under the combined action of gravity and external load should be the same as the relationship between the normal stress ratio and strain in formulas (6) and (7), that is, both are linear relationships. In this regard, it can be assumed that the normal stress and external load distortion ratios under gravity are still linearly related to the average normal displacement distortion ratio. The normal stress under gravity is related to the model matrix density, crack filling density, gravitational acceleration and size. The distortion of gravitational acceleration and size can be avoided in the model test. Therefore, the assumption that the matrix density, crack filling density and external load are linearly related to the average normal displacement distortion ratio can be expressed by (8), (9) and (10).

[0077] (8)

[0078] (9)

[0079] (10)

[0080] When conducting physical model tests on fractured rock masses, it is difficult to achieve complete similarity simulation of small fractures in large-scale physical models. Therefore, when considering the influence of fracture width distortion on the average normal displacement of the model, it is necessary to consider the large distortion of fracture width. The distortion of fracture width will lead to changes in the model itself. As the distortion ratio gradually increases, the proportion of fractures in the total model increases continuously. Since the fractures are treated as low-elastic-modulus, low-density filling materials, it can be assumed that the normal displacement distortion ratio of the model is linearly related to the fracture width distortion ratio. The linear relationship can be expressed as (11).

[0081] (11)

[0082] When the fracture width is distorted, the model itself changes. At this point, the distortion of other single-factor physical parameters, besides the fracture width, remains the same as when the fracture width is not distorted, but the coefficients change. Therefore, it is necessary to consider the impact of fracture width variation on the relationship between the single-factor physical parameter distortion and the mean normal displacement distortion. If the impact on the relationship between the single-factor physical parameter distortion and the mean normal displacement distortion is small under extreme fracture width distortion ratios, it can be ignored, and the subsequent study can proceed according to the relationship function when the fracture width is not distorted. However, if the impact is significant, the two-dimensional curve function relationship between the single-factor physical parameter distortion and the mean normal displacement distortion is transformed into a three-dimensional surface function relationship considering fracture width distortion. Given that the normal displacement distortion ratio of the model is linearly related to the fracture width distortion ratio, when the distortion ratio of a single-factor physical parameter is linearly related to the average normal displacement distortion ratio of the model, formula (12) can be used to express the three-dimensional functional relationship between the normal displacement distortion ratio of the model considering fracture width distortion and the distortion ratio of the single-factor physical parameter. When the distortion ratio of a single-factor physical parameter is inversely proportional to the average normal displacement distortion ratio of the model, formula (13) can be used to express the three-dimensional surface functional relationship considering fracture width distortion.

[0083] (12)

[0084] (13)

[0085] Based on the previous analysis of the influencing factors of the incomplete similarity of the single-fracture mechanical model of fractured rock mass, finite element simulation was carried out to verify the relationship between the distortion of the single-factor physical parameters and the distortion of the average normal displacement of the model after the prototype was scaled down. The corresponding laws were summarized from these relationships, and a compensation and correction method for the incomplete similarity of the single-fracture mechanical model of fractured rock mass was proposed.

[0086] After scaling down the single-crack non-penetrating model, the seven π-term similarity criteria are distorted respectively. The distortion of the single-factor physical parameter in formula (3) is used to represent the distortion of the π-term. Keeping other variables unchanged, the relationship between the distortion ratio of different similarity criteria and the average normal displacement distortion ratio of the model after compression is analyzed.

[0087] Of the seven similarity criteria derived from ρ, g, and L as basic physical quantities, the distortions of π1, π2, and π7 are related to the distortions of the elastic modulus, fracture elastic modulus, and fracture filler density. In actual physical model testing, the distortions of these three components can be controlled within a very small range during the fabrication of similar materials. Therefore, in numerical simulations, the distortion ratios of π1, π2, and π7 are simulated between 0.5 and 2. The distortion of π3 is related to fracture width distortion. In rock engineering, most fracture widths are often very small, and it is difficult to simulate fracture widths less than 1 mm in large-scale physical model tests. Therefore, the simulation of the π3 distortion ratio is conducted between 0.2 and 100. The distortion of π3 is related to external load distortion. The parameters of external loads can be well controlled in actual physical model tests and can serve as a good compensation term. Therefore, the simulation of the π3 distortion ratio is conducted between 0.2 and 5. The distortions of π5 and π6 are Poisson's ratio distortions and crack-filling Poisson's ratio distortions. Since the Poisson's ratio of the material is known to be in the range of 0 to 0.5, π5 and π6 are simulated with distortion ratios between 0.6 and 1.4 to control the range of the distorted Poisson's ratio to be between 0 and 0.5.

[0088] This application studies a method for compensating and correcting for incomplete similarity in single-fracture mechanical models of fractured rock masses based on numerical simulation. Firstly, it focuses on... Figure 3 Using the existing model as a prototype, a scaled-down model with a size similarity ratio of 100 was established using the finite element method and calculations were performed. Next, the single-factor physical parameters of the model were modified to achieve the target distortion ratio, and the final average normal displacement distortion ratio of the model was recorded. Each single-factor physical parameter underwent five distortion iterations. The data points were then plotted on a graph with the π-term distortion ratio on the horizontal axis and the average normal displacement distortion ratio on the vertical axis. A fitting formula was used to fit the data points, thus obtaining the relationship function between the π-term distortion ratio and the average normal displacement distortion ratio.

[0089] Meanwhile, a model with a fracture width distortion ratio of 100 was established and the calculation was completed. The relationship curve was established using the same method as the above steps. If the ratio of the relationship function with a fracture width distortion ratio of 100 to the parameter of the relationship function with no distortion of the fracture width is in the range of 0.95 to 1.05, then it is considered that the influence of the fracture width distortion ratio on the relationship between the single-factor physical parameter distortion process and the average normal displacement distortion is small and can be ignored. In this case, the subsequent study is carried out according to the relationship function when the fracture width is not distorted. However, if the ratio is not in the range of 0.95 to 1.05, then the single-factor physical parameter distortion needs to be performed 5 times at fracture width distortion ratios of 10, 25, 50, and 100. The final average normal displacement distortion ratio of the model is recorded. These data points are plotted on a three-dimensional graph with the fracture width distortion ratio as the X-axis, the single-factor physical parameter distortion as the Y-axis, and the average normal displacement of the model as the Z-axis. The formulas (12) and (13) are used for fitting to obtain the final function surface relationship.

[0090] The relationship between the distortion ratio of the single-factor physical parameters of the single-crack mechanical model and the distortion ratio of the model's average normal displacement is the same as the relationship between the distortion ratio of the π-term and the distortion ratio of the model's average normal displacement. Finally, the diagram of the distortion ratio of the π-term and the distortion ratio of the model's average normal displacement is obtained.

[0091] Analysis of the influencing factors of the incomplete similarity of the single-crack model reveals a linear relationship between the model's average normal displacement distortion ratio and the distortion ratios of π3, π4, π5, π6, and π7. Among these, the distortions of π6 and π7 have a relatively small impact on the model's average normal displacement and are therefore not included in the scope of distortion compensation and correction. Furthermore, the ratios of π1 and π2, obtained from the basic physical quantities ρ, g, and L, are inversely proportional and are also affected by the π3 distortion ratio. The distortion formula for the π term of this single-crack model, based on ρ, g, and L as the basic physical quantities, is (14):

[0092] (14)

[0093] Therefore, we can summarize the distortion formula for the π term based on ρ, g, and L as the fundamental physical quantities (15):

[0094] (15)

[0095] After determining the distortion formulas for each π term and the average normal displacement of the model, since the distortion formula for each π term independently affects the average normal displacement of the model, the distortion formula for the average normal displacement of the model under multiple π term distortions can be expressed by formula (17).

[0096] (17)

[0097] When the distortion ratio of the model's average normal displacement δ n When =1, the average normal displacement of the model does not distort. At this time, the incompletely similar model achieves the same test results as the completely similar model through distortion compensation. The compensation formula for the incomplete similarity of the single-fracture mechanical model of fractured rock mass is expressed by formula (18).

[0098] (18)

[0099] When one or more π terms in a single-fracture model of fractured rock mass fail to meet the complete similarity condition during scaling down, the distortion ratio of the π terms that fail to meet the complete similarity relationship can be substituted into the compensation formula (18). One or more π terms that are easy to control and change during the test are selected as compensation π terms, and the calculation is completed to obtain the distortion ratio of the compensation π terms. After obtaining all parameters, the model test is redesigned, and finally the distortion compensation is completed so that the model test approximates the actual situation.

[0100] 1.2 Validation of the compensation method for incomplete similarity in single-crack models

[0101] Based on the above study of the single-fracture mechanical model of fractured rock mass, it was found that only the distortion of the five π terms has a significant impact on the average normal displacement distortion of the model. Therefore, in the numerical simulation verification, four π terms were randomly selected within the distortion range of each π term for simulation. However, it is necessary to ensure that the selected compensation π terms have a significant impact on the average normal displacement distortion ratio of the model within the distortion range. By substituting the selected distortion ratios into the compensation formula, the distortion ratio of the compensation π terms can be obtained, and the model parameters are modified to achieve the distortion ratios of each π term. Subsequently, simulation experiments are conducted to obtain the average normal displacement of the final model. Then, the average normal displacement distortion ratio δ of the incompletely similar model is calculated. n If the average normal displacement distortion ratio δn of all compensated models is between 0.95 and 1.05, then the compensated models can be considered to have achieved the experimental results achieved by the fully similar models, that is, the compensation method is effective.

[0102] The average normal displacement distortion ratio δ of the incompletely similar model after compensation based on ρ, g, L as the basic physical quantities and similarity criteria based on E, g, L as the basic physical quantities is δ. n The results are shown in Table 4.

[0103]

[0104] Table 4 shows that the δ of the incompletely similar model after compensating for the π term using the compensation method... n The values ​​are all between 0.95 and 1.05. Therefore, after using the compensation method, the average normal displacement of the incompletely similar model reached the experimental results achieved by the completely similar model, and the compensation method is effective.

[0105] 2. Compensation method and verification for incomplete similarity in fractured network models

[0106] 2.1 Compensation Method for Incomplete Similarity in Slit Network Models

[0107] Taking a fracture network model with 100 random fractures as an example, this study investigates the influencing factors and compensation / correction methods for the incomplete similarity of the fracture network mechanical model in fractured rock mass. A plane strain uniaxial compression model of the fracture network is established using finite element software, with granite as the prototype and elastic material as the fracture network model material. The matrix is ​​assigned an elastic modulus E, Poisson's ratio μ, and density ρ. When simulating the fracture width, the fractures are treated as a low-elastic-modulus E, low-density ρ filler material, and an elastic modulus E is assigned to the fractures. f Poisson's ratio μ f and density ρ f ,like Figure 4 As shown, a mechanical model diagram of a single fracture in a fractured rock mass is presented.

[0108] The fracture network model and the single fracture model are identical in structure and mechanical parameters, except for the number of fractures. Therefore, the factors affecting the incomplete similarity of the fracture network mechanical model of fractured rock mass are the same as those affecting the incomplete similarity of the single fracture mechanical model of fractured rock mass. The similarity criteria, distortion equations, and single-factor distortion equations obtained by the fracture network model based on ρ, g, and L are shown in equations (1) to (3) above.

[0109] The relationship between the distortion of single-factor physical parameters and the average normal displacement of the model is the same as that between the distortion of single-factor physical parameters and the average normal displacement of the model in the single-fracture model, as shown in formulas (6) to (11). The relationship between the distortion of single-factor physical parameters and the average normal displacement in the fracture network model considering the effect of fracture width variation on the distortion of single-factor physical parameters is the same as that between the distortion of single-factor physical parameters and the average normal displacement of the model in the single-fracture model considering the effect of fracture width variation on the distortion of single-factor physical parameters, as shown in formulas (12) and (13).

[0110] Based on the aforementioned analysis of the influencing factors of the incomplete similarity of the fracture network mechanical model of fractured rock mass, finite element simulation is carried out to verify the relationship between the distortion of single-factor physical parameters and the distortion of the average normal displacement of the model after the prototype is scaled down. The corresponding laws are summarized from these relationships, and a compensation and correction method for the incomplete similarity of the fracture network mechanical model of fractured rock mass is proposed.

[0111] When performing finite element simulations to verify the relationship between the distortion of single-factor physical parameters and the distortion of the mean normal displacement of the model after prototype scaling, the process is the same as verifying the relationship between the distortion of single-factor physical parameters and the distortion of the mean normal displacement of the model after prototype scaling of the single-fracture model. The relationship between the distortion ratio of single-factor physical parameters and the distortion ratio of the mean normal displacement of the fracture network mechanical model is the same as the relationship between the π-term distortion ratio and the distortion ratio of the mean normal displacement of the model, and finally, a diagram of the π-term distortion ratio and the distortion ratio of the mean normal displacement of the model is obtained.

[0112] Analysis of the influencing factors of incomplete similarity in the fracture network model reveals a linear relationship between the model's average normal displacement distortion ratio and the distortion ratios of π5, π6, and π7; the model's average normal displacement distortion ratio is also linearly related to the distortion ratios of π2 and π3, and is influenced by the π5 distortion ratio. The π7 distortion has a relatively small impact on the model's average normal displacement and is therefore not included in the distortion compensation and correction scope. Furthermore, the model's average normal displacement distortion ratio is inversely proportional to the ratios of π1 and π4 obtained from the basic physical quantities ρ, g, and L, and is also influenced by the π5 distortion ratio. The finite element model diagram of the fracture network uses the π-term distortion formula (19) based on ρ, g, and L as the basic physical quantities.

[0113] (19)

[0114] Therefore, we can summarize the distortion formula for the π term based on ρ, g, and L as the basic physical quantities (20).

[0115] (20)

[0116] After determining the distortion formulas for each π term and the average normal displacement of the model, since the distortion formula for each π term independently affects the average normal displacement of the model, the distortion formula for the average normal displacement of the model under multiple π term distortions can be expressed by formula (21).

[0117] (twenty one)

[0118] When the distortion ratio of the model's average normal displacement δ n When the value is 1, the average normal displacement of the model does not change. At this time, the incompletely similar model achieves the same test results as the completely similar model through distortion compensation. The compensation formula for the incomplete similarity of the single-fracture mechanical model of fractured rock mass is expressed by formula (22).

[0119] (twenty two)

[0120] 2.2 Validation of the compensation method for incomplete similarity in the fractured network model

[0121] Based on the above study of the finite element model of fractured rock mass fracture network, it was found that only the distortion of the six π terms has a significant impact on the average normal displacement distortion of the model. Therefore, in the numerical simulation verification, the distortion ratios of the six π terms were randomly selected within the distortion range of each π term for simulation. However, it is necessary to ensure that the selected compensation π terms have a significant impact on the average normal displacement distortion ratio of the model within the distortion range. By substituting the selected distortion ratios into the compensation formula, the distortion ratio of the compensation π terms can be obtained, and the model parameters are modified to achieve the distortion ratios of each π term. Subsequently, simulation experiments are conducted to obtain the average normal displacement of the final model. Then, the average normal displacement distortion ratio δ of the incompletely similar model is calculated. n If the average normal displacement distortion ratio of all compensated models is δ n If the values ​​are all between 0.95 and 1.05, then the compensated model can be considered to have achieved the experimental results achieved by the completely similar model, that is, the compensation method is effective.

[0122] The average normal displacement distortion ratio δ of the incompletely similar model after compensation based on ρ, g, L as the basic physical quantities and similarity criteria based on E, g, L as the basic physical quantities is δ. n The results are shown in Table 5.

[0123]

[0124] As can be seen from Table 5, the δ of the incompletely similar model after compensating for the π term using the compensation method... nThe values ​​are all between 0.95 and 1.05. Therefore, after using the compensation method, the average normal displacement of the incompletely similar model reached the experimental results achieved by the completely similar model, and the compensation method is effective.

[0125] By comparing the displacement cloud map of the compensated model with that of the prototype, it can be analyzed that the displacement of each block in the model after distortion compensation is basically the same as that of the prototype, and can reflect the phenomenon of the prototype. Therefore, this method can be used to make the compensation method effective.

[0126] 3. Compensation method and verification for incomplete similarity of underground chamber models

[0127] A mechanical model of an underground chamber in fractured rock mass was constructed using two-dimensional discrete element method (DEM) software. Based on the excavated chamber, the model first establishes an equilibrium state before excavation to ensure stress equilibrium before actual excavation. The excavation shape is horseshoe-shaped, with a focus on observing whether damage occurs at the top of the chamber and monitoring strain changes at three monitoring points at the top during excavation. The dimensions and boundaries of the model after excavation are shown below. Figure 5 As shown. The joint and fracture network is constructed based on fracture surface structures with a mean of 45° and a variance of 2 (Gaussian distribution) and fracture surface structures with a mean of 135° and a variance of 2. Using granite as the material prototype, the material properties of the fractured rock mass tunnel mechanical model are detailed in Table 6.

[0128]

[0129] Both the fractured rock mass underground chamber model and the fracture network mechanics model are discrete element models and have the same model parameters. Therefore, the factors affecting the incomplete similarity of the fractured rock mass underground chamber model are the same as those of the fracture network mechanics discrete element model. The similarity criteria, distortion equations and single-factor distortion equations obtained by the fracture network model based on ρ, g and L are shown in (23) to (25).

[0130] (twenty three)

[0131]

[0132] (twenty four)

[0133]

[0134] (26)

[0135] From (25), it can be seen that the distortion of the π term, a factor of incomplete similarity in the fractured rock mass underground chamber model, can be converted into the distortion of the seven physical parameters as single factors. The influence of the distortion of the single-factor physical parameters on the normal displacement of the monitoring point of the stable underground chamber model is the same as the influence of the single factor on the average normal displacement in the discrete element model of the fractured rock mass fracture network. The relationship between the distortion of the single-factor physical parameters of the stable underground chamber model and the normal displacement of the model monitoring point is given by formulas (6)~(10), (12)~(13).

[0136] When studying the incomplete similarity compensation of underground chamber models, the prototypes are divided into two types: one is a stable chamber model after excavation, i.e., a stable model; the other is a chamber model that fails after excavation, i.e., a failure model.

[0137] The main difference between the stable and failure models lies in the top load, while the materials and boundary conditions remain the same. For the stable model, the relationship between the distortion of single-factor physical parameters and the normal displacement of the tunnel roof under stable conditions is analyzed, and corresponding rules are summarized from these relationships. Based on these rules, a compensation method using a discrete element model of fractured rock mass fracture network is adopted to compensate for the distortion model within the model's stable parameter range. For the failure model, it is necessary to identify the single-factor distortion factors affecting model failure through single-factor distortion, and use a bisection method to explore the relationship between these single-factor distortions under the ultimate failure state, thereby summarizing the compensation rules for the failure model.

[0138] 3.1 Compensation Method for Incomplete Similarity of Underground Chamber Stability Models

[0139] Discrete element method (DEM) software was used to verify the relationship between the distortion of single-factor physical parameters of the model and the distortion of the normal displacement at monitoring points after scaling up the prototype of the single-fracture model. The relationship between the distortion ratio of single-factor physical parameters of the fracture network underground chamber model and the distortion ratio of the model's average normal displacement is the same as the relationship between the π-term distortion ratio and the model's average normal displacement distortion ratio. Finally, a diagram showing the π-term distortion ratio and the model's average normal displacement distortion ratio was obtained, as shown below. Figure 6 As shown.

[0140] When analyzing the influencing factors of incomplete similarity in the discrete element model of the fractured network, the model displacement distortion ratio of the monitoring points where block detachment occurred was defined as 10. This was to clearly identify the limiting π-term distortion ratio that led to the block detachment in the relationship diagram between π-term distortion and displacement distortion. Data analysis shows that for a stable chamber model, distortions of π5 and π6 cause the model to transition from a stable state to a failed state, at which point the distorted model and the prototype are no longer consistent in state. Therefore, when analyzing the influence of distortion on displacement in the stable state model, it is necessary to exclude the π-term distortion ratio data points of detached blocks after distortion, and to use the fitting function relationship of the discrete element model of the fractured rock mass fractured network when fitting the function.

[0141] Furthermore, the distortions of the two π terms in π6 and π7 are related to the shear strength of the model's structural surfaces. Under load, the distortions of π6 and π7 may cause some structural surfaces in the model to transition between a failure state and a stable state. Due to the differences in the position and angle of the structural surfaces, the stresses they bear are different, making it difficult to accurately analyze whether the structural surfaces have failed. Because the relationship between the distortion ratios of π6 and π7 and the displacement distortion ratio of the monitoring points is uncertain, the influence of the distortions of π6 and π7 on the displacement of the model's monitoring points is not considered when compensating for a stable underground chamber model.

[0142] According to the fitting function relationship graph, the average normal displacement distortion ratio of the model is linearly related to the distortion ratios of π2 and π5; the average normal displacement distortion ratio of the model is inversely proportional to the distortion ratios of π1, π3, and π4. The underground chamber model diagram of the fractured rock mass uses the distortion formula (26) of the π term based on the basic physical quantities ρ, g, and L.

[0143] (26)

[0144] Therefore, we can summarize the distortion formula for the π term based on ρ, g, and L as the fundamental physical quantities (27).

[0145] (27)

[0146] After determining the distortion formulas for each π term and the normal displacement distortion formulas for the monitoring points in the underground chamber, since the distortion formula for each π term independently affects the normal displacement of the monitoring points, the distortion formula for the normal displacement of the monitoring points under multiple π term distortions is expressed by formula (28).

[0147] (28)

[0148] When the distortion ratio δn of the normal displacement of the monitoring point is 1, the normal displacement of the monitoring point of the model does not distort. At this time, the incompletely similar model achieves the same test results as the completely similar model through distortion compensation. The compensation formula for the incomplete similarity of the stability model of the underground chamber of fractured rock mass is expressed by formula (29).

[0149] (29)

[0150] When conducting scaled-down studies of underground chamber models, if one or more π terms are found to be unable to meet the perfect similarity condition, the distortion ratio of the π terms that cannot meet the perfect similarity relationship can be substituted into the compensation formula (29). In this process, one or more π terms that are easy to control and change during the test are selected as compensation π terms and calculated to obtain the distortion ratio of the compensation π terms. After obtaining all parameters, the model test is redesigned, and finally the distortion compensation is completed, so that the model test can be closer to the actual situation. During the compensation process, it should be noted that an excessively large external load distortion ratio may cause the model to be damaged. Therefore, when compensating a stable model, the external load distortion ratio should be as small as possible to be less than 1.

[0151] 3.2 Validation of the compensation method for incomplete similarity of the stability model of underground chambers

[0152] Based on the above study on the stability model of underground chambers in fractured rock masses, the distortion of the five π terms has a significant impact on the average normal displacement distortion of the model. Therefore, in the numerical simulation verification, the distortion ratios of five π terms were randomly selected within the distortion range of each π term for simulation. However, it is necessary to ensure that the selected compensation π terms have a significant impact on the normal displacement distortion ratio of the model monitoring points within the distortion range. By substituting the selected distortion ratios into the compensation formula, the distortion ratio of the compensation π terms can be obtained, and the model parameters are modified to achieve the distortion ratios of each π term. Subsequently, simulation experiments are conducted to obtain the normal displacement of the monitoring points of the final model. Then, the normal displacement distortion ratio δ of the monitoring points of the incompletely similar model is calculated. n If the normal displacement distortion ratio δ at each monitoring point of the compensated model is... n If the values ​​are all between 0.95 and 1.05, then the compensated model can be considered to have achieved the experimental results achieved by the completely similar model, that is, the compensation method is effective.

[0153] The normal displacement distortion ratio δ at the monitoring points of the incompletely similar model after compensation based on similarity criteria using ρ, g, and L as the basic physical quantities. n The results are shown in Table 7.

[0154]

[0155] Table 7 shows that the δ of the incompletely similar model after compensating for the π term using the compensation method... n The values ​​are all between 0.95 and 1.05. Therefore, after using the compensation method, the average normal displacement of the incompletely similar model reached the experimental results achieved by the completely similar model, and the compensation method is effective.

[0156] By comparing the displacement cloud map of the compensated model with that of the prototype, it can be concluded that the displacement of each block in the model after distortion compensation is basically the same as that of the prototype, and can reflect the phenomenon of the prototype. Therefore, the compensation method is effective.

[0157] 3.3 Compensation Method for Incomplete Similarity of Underground Chamber Failure Model

[0158] By analyzing the relationship between the π-term distortion ratio of the stable model and the normal displacement distortion ratio of the model monitoring points, it can be seen that distortions of π5 and π6 will cause the model to transition from a stable state to a failed state. To ensure that the scaled-down model remains in a failed state consistent with the prototype, the distortion relationship between π5 and π6 is analyzed in the study of failed model compensation to determine when the model failure conditions are met before compensation is carried out.

[0159] For the failure model, the material and boundary conditions remain consistent with the stable model. Increasing the load at the top of the model causes the top block of the chamber to detach, which is defined as the failure model. In the discrete element method (DEM) software, the fractured rock mass is elastic, and the structural surface imparts Coulomb slip at surface contact. Its failure principle is the Coulomb criterion of the structural surface. Therefore, the detachment of the top block of the chamber is due to the shear strength of the structural surface exceeding its shear strength. It can be seen that the compensation for the failure model differs from the fixed value of the stable model, but rather is a range. When the shear strength of the structural surface exceeds its shear strength, the model can well represent the prototype. Therefore, it is necessary to find the relationship between the π5 and π6 distortion ratios under the ultimate failure state of the structural surface at the top of the chamber to determine the compensable range.

[0160] In the study of physical model failure tests of underground tunnels, loading the model to cause failure after its fabrication is often the final step in the experiment. Therefore, π6, which is related to the cohesion parameter of the structural surface, is used as the distortion term. The distortion ratio of the π5 term related to the external load under the ultimate failure state of the model is found using the bisection method. Subsequently, the distortion ratios of π6 and π5 under the ultimate failure state of the model are plotted in a graph, and a linear relationship is fitted. The fitted graph is shown below. Figure 7 As shown.

[0161] After determining the relationship between the π5 and π6 distortion ratios under the ultimate failure state of the model, the distortion model compensation satisfies formula (30), i.e. Figure 7 The dark areas in the medium shades allow the scaled-down model to conform to the damaged state of the original.

[0162] (30)

[0163] The compensation formula for the incomplete similarity of the failure model of the underground chamber of the fractured rock mass is expressed by formula (31).

[0164] (31)

[0165] When conducting a failure model test of an underground chamber excavation, if some π terms cannot meet the conditions for complete similarity, it is sufficient to make π5 and π6 satisfy formula (31) during the distortion process so that the model can present the failure state of the prototype and complete the distortion compensation.

[0166] 3.4 Verification of the compensation method for incomplete similarity in the failure model of underground chambers

[0167] Based on the above study on the failure model of underground chambers in fractured rock masses, the distortion of the two π terms affects the model failure. Therefore, during numerical simulation verification, the distortion ratio of π6 is randomly selected and substituted into formula (30) to find the π5 distortion ratio that meets the requirements. Substituting the selected distortion ratio into the compensation formula can obtain the distortion ratio of the compensation π term, and the model parameters are modified to achieve the distortion ratio of each π term. Subsequently, a simulation test is conducted to observe the normal displacement of the monitoring points and whether there is any block falling off at the top. If the blocks falling off the top of all compensated models are consistent with the prototype, it can be considered that the compensated model has achieved the test results achieved by the completely similar model, that is, the compensation method is effective.

[0168] Two distortion models were selected for compensation verification of the damage model. The distortion ratios of π6 and π5 were changed to conform to the relationship of formula (30). Then, the excavation calculation of the underground chamber model was performed, and it was observed whether the block that fell off the top of the model was consistent with the prototype. Figure 8 It can be seen that the destruction of the two distortion models is consistent with that of the completely similar model, thus confirming that the compensation method is effective.

[0169] In this embodiment, firstly, a compensation formula for the discontinuous fractured rock mass model is determined based on the model type. Then, based on the compensation formula and the π-term distortion occurring during the model test, distortion parameters for the π-term are obtained. Finally, a compensated model for the discontinuous fractured rock mass model is generated based on these distortion parameters. Thus, by studying the influence of distortion from various similarity criteria on the model, a compensation method for an incompletely similar fractured rock mass model is proposed, enabling the compensated model to better represent the original model.

[0170] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0171] The following are device embodiments of this application. For details not described in detail, please refer to the corresponding method embodiments described above.

[0172] Compensation devices for incomplete similarity in discontinuous fractured rock mass model tests include:

[0173] The compensation formula determination module is used to determine the compensation formula for the discontinuous fractured rock mass model based on the model type of the discontinuous fractured rock mass model.

[0174] The distortion parameter calculation module is used to obtain the distortion parameters of the π term to compensate for the distortion of the discontinuous fracture rock mass model based on the compensation formula of the discontinuous fracture rock mass model and the π term distortion that occurs during the discontinuous fracture rock mass model test.

[0175] The compensation model generation module is used to generate a compensation model for a discontinuous fractured rock mass model based on distortion parameters.

[0176] In some embodiments, the distortion parameter calculation module is specifically used for:

[0177] The π-terms that fail to satisfy the perfect similarity relationship during the model test of discontinuous fractured rock mass are identified as π-term distortions.

[0178] Substitute the distortion ratio of the π-term distortion into the compensation formula, and select at least one π-term to calculate the distortion ratio of the compensated π-term, thereby obtaining the distortion parameter of the compensated π-term.

[0179] In some embodiments, the compensation model generation module is specifically used for:

[0180] The model parameters are modified to compensate for the distortion ratio of the π term;

[0181] If the normal displacement distortion ratio of the model is within the preset range, then the model at this time is determined as the compensation model of the discontinuous fractured rock mass model.

[0182] If the normal displacement distortion ratio of the model is not within the preset range, the process of "selecting at least one π term to compensate for the distortion ratio of the π term, modifying the model parameters to compensate for the distortion ratio of the π term" is repeated until the normal displacement distortion ratio of the model is within the preset range, and the model at this time is determined as the compensation model of the discontinuous fractured rock mass model.

[0183] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0184] Furthermore, the features of the embodiments shown in the accompanying drawings or the various embodiments mentioned in this specification should not be construed as independent embodiments. Rather, each feature described in one example of an embodiment can be combined with one or more other desired features from other embodiments to produce other embodiments not described in words or with reference to the accompanying drawings.

[0185] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0186] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for compensating for incomplete similarity in a model test of a discontinuous fractured rock mass, characterized by, The method comprises the following steps: According to the model type of the discontinuous fractured rock mass model, a compensation formula of the discontinuous fractured rock mass model is determined; According to the compensation formula of the discontinuous fractured rock mass model and the π term distortion occurring in the test process of the discontinuous fractured rock mass model, a distortion parameter of the compensation π term is obtained; According to the distortion parameter, a compensation model of the discontinuous fractured rock mass model is generated.

2. The method of claim 1, wherein the method is characterized by: The method according to the model type of the discontinuous fractured rock mass model, the compensation formula of the discontinuous fractured rock mass model comprises: When the model type of the discontinuous fractured rock mass model is a single fracture model, the compensation formula is: wherein, wherein, π1-π5 are π terms obtained from the basic physical quantities of rock mass matrix density ρ, gravity acceleration g, and size L, the subscript p in the π term represents the prototype, the subscript m in the π term represents the fractured rock mass model, δ π represents the distortion coefficient of different π terms, E f represents the elastic modulus of the fracture filler, E represents the elastic modulus, d represents the fracture gap width, μ represents the Poisson's ratio of the rock mass matrix, P represents the external load, d1 and d2 represent fitting parameters.

3. The method of claim 1, wherein the method is a method for compensating for the incomplete similarity of a discrete fracture model test, characterized by, The method according to the model type of the discontinuous fractured rock mass model, the compensation formula of the discontinuous fractured rock mass model comprises: When the model type of the discontinuous fractured rock mass model is a fracture network model, the compensation formula is: wherein, wherein, π1-π6 are π terms obtained from the basic physical quantities of rock mass matrix density ρ, gravity acceleration g, and size L, the subscript p in the π terms represents the prototype, the subscript m in the π terms represents the fractured rock mass model, δ π represents the distortion coefficient of different π terms, E f represents the elastic modulus of the fracture filler, E represents the elastic modulus, d represents the fracture gap width, μ represents the rock mass matrix Poisson's ratio, P represents the external load, μ f represents the Poisson's ratio of the fracture filler, d1 and d2 represent fitting parameters.

4. The method of claim 1, wherein the method is a method for compensating for incomplete similarity in a discrete fracture network model test, characterized by, The method according to the model type of the discontinuous fractured rock mass model, the compensation formula of the discontinuous fractured rock mass model comprises: When the model type of the discontinuous fractured rock mass model is a post-excavation stable underground chamber model, the compensation formula is: wherein, wherein, π1-π5 are π terms obtained from the basic physical quantities of rock mass matrix density p, gravity acceleration g, and size L, the subscript p in the π term represents the prototype, the subscript m in the π term represents the fractured rock mass model, δ π represents the distortion coefficient of different π terms, E represents the elastic modulus, μ represents the Poisson's ratio of the rock mass matrix, K n represents the normal stiffness of the joint, K s represents the tangential stiffness of the joint, and P represents the external load.

5. The method of claim 1, wherein the method is a method for compensating for incomplete similarity in a discrete fracture network model test, characterized by, The method according to the model type of the discontinuous fractured rock mass model, the compensation formula of the discontinuous fractured rock mass model comprises: When the model type of the discontinuous fractured rock mass model is a post-excavation failure underground chamber model, the compensation formula is: Wherein, π6 is a π term based on the physical quantities of rock mass matrix density ρ, gravity acceleration g and size L, c is joint cohesion, and a and b represent fitting coefficients.

6. The method according to any one of claims 1 to 5, wherein The method according to the compensation formula of the discontinuous fractured rock mass model and the π term distortion occurring in the test process of the discontinuous fractured rock mass model, the distortion parameter of the compensation π term is obtained, which comprises: The π term that cannot meet the complete similarity relationship occurring in the test process of the discontinuous fractured rock mass model is determined as the π term distortion; The distortion ratio of the π term distortion is substituted into the compensation formula, and at least one π term is selected to calculate the distortion ratio of the compensation π term, so as to obtain the distortion parameter of the compensation π term.

7. The method of claim 6, wherein the method is characterized by: The method according to the distortion parameter, the compensation model of the discontinuous fractured rock mass model is generated, which comprises: The model parameters are modified to achieve the distortion ratio of the compensation π term; If the normal displacement distortion ratio of the model is in the preset interval, the model at this time is determined as the compensation model of the discontinuous fractured rock mass model; If the normal displacement distortion ratio of the model is not in the preset interval, the method of "selecting at least one π term to calculate the distortion ratio of the compensation π term, and modifying the model parameters to achieve the distortion ratio of the compensation π term" is repeated until the normal displacement distortion ratio of the model is in the preset interval, and the model at this time is determined as the compensation model of the discontinuous fractured rock mass model.

8. A device for compensating for incomplete similarity in a model test of a discontinuous fractured rock mass, characterized in that The method comprises the following steps: A compensation formula determination module is configured to determine a compensation formula of the discontinuous fractured rock mass model according to the model type of the discontinuous fractured rock mass model; A distortion parameter calculation module is configured to obtain a distortion parameter of the compensation π term according to the compensation formula of the discontinuous fractured rock mass model and the π term distortion occurring in the test process of the discontinuous fractured rock mass model; A compensation model generation module is configured to generate a compensation model of the discontinuous fractured rock mass model according to the distortion parameter.

9. The apparatus according to claim 8, wherein The distortion parameter calculation module is specifically configured to: The π term that cannot satisfy the complete similarity relationship in the process of the model test of the discontinuous fractured rock mass is determined as a π term distortion; The distortion ratio of the π term distortion is substituted into the compensation formula, and at least one π term is selected to calculate the distortion ratio of the compensation π term, to obtain a distortion parameter of the compensation π term.

10. The apparatus according to claim 9, wherein The compensation model generation module is specifically configured to: modify the model parameters to compensate for the distortion ratio of the π term; if the normal displacement distortion ratio of the model is within the preset interval, the model at this time is determined as the compensation model of the discontinuous fractured rock mass model; if the normal displacement distortion ratio of the model is not within the preset interval, the process of "selecting at least one π term to calculate the distortion ratio of the compensation π term, and modifying the model parameters to compensate for the distortion ratio of the π term" is repeated until the normal displacement distortion ratio of the model is within the preset interval, and the model at this time is determined as the compensation model of the discontinuous fractured rock mass model.

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