Quantitative analysis method and system for diffusion effect of water-rich soft rock splitting permeation and collaborative grouting

Abstract

This invention relates to the field of geological engineering, specifically to a method and system for quantitatively analyzing the diffusion effect of synergistic grouting in water-rich soft rock fracturing and seepage. The method includes: conducting parameter tests and obtaining time-varying characteristic parameters through orthogonal experiments; establishing a coupled dynamic model including the grout volumetric flow rate equation, seepage motion equation, and flow continuity equation to obtain the spatiotemporal distribution of the grout field, the flow distribution coefficient of the dual-domain coupling, and the grouting parameters at different grouting times; constructing an index system with synergistic effects and obtaining quantitative values ​​of the diffusion effect. This invention constructs a dual-domain coupled dynamic model that couples the grout volumetric flow rate equation, seepage motion equation, flow continuity equation, and stress continuity equation, modifies the classical flow law to adapt to the grout yield stress characteristics, and achieves transient analysis through finite element numerical solution. It can output the spatiotemporal distribution of the grout field, the flow distribution coefficient, and the grouting parameters, and determine the micro-zone division boundary threshold based on experimental data.

Description

Technical Field

[0001] This invention relates to the field of geological engineering, specifically to a quantitative analysis method and system for the diffusion effect of grouting combined with fracturing and permeability in water-rich soft rock. Background Technology

[0002] Water-rich soft rock strata are characterized by abundant water, poor rock mass cementation, and low mechanical strength. They also exhibit a dual-medium structure of primary fissures and bedrock pores. Grout in these strata undergoes both fissure splitting and pore infiltration diffusion, making them a typical difficult-to-treat stratum for underground engineering grouting reinforcement.

[0003] Current technologies for diffusion analysis and effect evaluation of grouting in water-rich soft rock have many inherent defects, making it difficult to meet the needs of precise engineering control. Existing technologies mostly conduct parameter detection of fractured or porous media separately, without integrating the parameters of the fracture flow domain and the bedrock porous media domain. They also ignore the time-varying characteristics of the grout, such as rheology and consolidation, during the grouting process. Furthermore, the coupled dynamics model has defects. Traditional grouting models only simulate the splitting flow or pore permeation process separately, without realizing dual-domain coupled analysis. Moreover, classical flow laws do not consider the influence of grout yield stress on the initiation of grout flow in fractures, and lack the coupling relationship between the continuity of flow and the continuity of stress at the dual-domain interface. Numerical solutions cannot truly reproduce the spatiotemporal distribution and transport laws of grout in the dual domains. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing a quantitative analysis method and system for the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: a quantitative analysis method for the diffusion effect of grouting in water-rich soft rock splitting and permeation, including the following steps: S100, the parameters of the fracture flow domain and the porous medium domain of bedrock grouting in water-rich soft rock are tested respectively, and time-varying characteristic parameters are obtained by combining orthogonal experiments. The obtained parameters are classified and stored, and a callable dual-domain parameter basic database is constructed. S200. Establish a coupled dynamic model of rock pore seepage and pressure fracturing, including the slurry volumetric flow rate equation, seepage motion equation, and flow continuity equation. Then, use the finite element method to substitute parameters from the dual-domain parameter database into the obtained coupled dynamic model for modal analysis, obtaining the spatiotemporal distribution of the slurry field and the flow distribution coefficient of the dual-domain coupling. Grouting parameters at different grouting times; S300. Based on the parameter test results obtained in S100, the boundary threshold for micro-region division is calculated and determined. The entire grouting diffusion micro-region is divided according to the boundary threshold. The synergistic effect of each micro-region is quantified to obtain the synergistic effect characteristic quantification parameters of each micro-region. The theoretical values ​​obtained based on the coupled dynamics model are compared with the actual values ​​in the synergistic effect characteristic quantification parameters of each micro-region to construct an index system with synergistic effect and obtain the quantification value of diffusion effect.

[0006] In a preferred embodiment, S100 specifically includes: Rock samples were taken using a geological drilling rig along a direction perpendicular to the rock strata, and the natural moisture content and natural density of the rock samples were tested using a drying method. After determining the particle specific gravity, the porosity is calculated using the volumetric method. In some other specific embodiments, this application drills standard cylindrical rock blocks with a diameter of 50 mm and a height of 100 mm, taking no fewer than 30 sets of samples. Parallel samples are also taken for water content and density testing. The rock blocks are placed in a triaxial permeameter, and a constant pore water pressure of 1 MPa, consistent with the engineering site, is applied. The variable head method is used to test the seepage flow rate of the rock samples under different hydraulic gradients. The permeability tensor of the bedrock porous medium is obtained by fitting the data. In the above, the original permeability characteristics parameters of water-rich soft rock are obtained, providing core parameters for the seepage control equation of porous media domain; The rock block was subjected to uniaxial compression, and its uniaxial compressive strength was obtained after the rock block failed. Elastic modulus In some other specific embodiments, this application uses an electro-hydraulic servo rock mechanics testing machine, with a loading rate set to 0.5 MPa / s until the sample fails, and the tensile strength of the rock block is obtained through a tension test. This means obtaining the basic mechanical parameters of water-rich soft rock to provide fundamental parameters for calculating surrounding rock stress and determining splitting initiation. Rock blocks with pre-fabricated fractures were then prepared, and their fracture toughness was tested. The fracture toughness of the water-rich soft rock was calculated using linear elastic fracture mechanics formulas. The critical mechanical parameters for fracture initiation and propagation in water-rich soft rocks were obtained, providing core criteria for the control equation of fracture propagation. Furthermore, pore structure tests were conducted on the rock samples to obtain the fractal dimension of the pore structure. In some other specific embodiments, the pre-fabricated fracture length is 0.4 times the sample height. An electro-hydraulic servo testing machine is used for loading at a rate of 0.05 mm / min. The critical load at fracture initiation is recorded. In the pore structure test, mercury intrusion porosimetry is used to test the pore structure of the rock sample. The pore size range is 5 nm to 200 μm. The mercury intrusion volume under different intrusion pressures is recorded. Based on fractal geometry theory, the fractal dimension of the rock sample's pore structure is obtained by linearly fitting the mercury intrusion volume to the pore size under double logarithmic coordinates. ; After completing the parameter testing of the fracture flow domain, standard rock samples with original fractures were scanned using a scanner to obtain three-dimensional point cloud data of the fracture surface. The fracture aperture was calculated by fitting the normal distance of the point cloud data. The average normal distance between the two walls of the fracture is calculated using the Barton profile comparison method to obtain the surface roughness coefficient of the fracture. The purpose of this step is to accurately obtain the geometric morphology parameters of a single fracture, providing core geometric parameters for the calculation of slurry flow within the fracture. Standard rock samples with native fractures were loaded into a seepage testing apparatus to measure the seepage flow rate under different hydraulic gradients. The fracture permeability tensor was obtained by fitting the sample using a modified cubic law. The specific operation is roughly as follows: apply axial pressure and pore water pressure consistent with the field, use the constant head method to test the seepage flow of the fracture under different hydraulic gradients, and complete the parameter test of the bedrock porous media domain by fitting the modified cubic law.

[0007] In a preferred embodiment, S100 further includes: Through orthogonal experiments, initial grouting pressure, grout type, and medium characteristics were used as independent variables, and grouting parameters were used as dependent variables to calibrate the experiments and obtain the initial yield stress of the grout. Instantaneous dynamic viscosity of slurry slurry density gel time , compressive strength of slurry solidified body and the permeability coefficient of the slurry solidified body ; The parameters of the porous bedrock medium domain, the parameters of the fracture flow domain, and the time-varying characteristics of the grout obtained through orthogonal experiments are classified and stored according to grouting pressure, grout type, and medium characteristics to construct a callable dual-domain parameter basic database.

[0008] In a preferred embodiment, S200 includes: Based on the initial yield stress of the obtained slurry With the instantaneous dynamic viscosity of the slurry Same slurry shear rate The sum of the products represents the shear stress of the slurry. : ; The single fracture in the rock sample was simplified into two parallel smooth plates, and the flow of slurry within the fracture was considered as one-dimensional laminar flow. The velocity distribution equation of the slurry within the fracture was derived. Then, by integrating the velocity distribution along the fracture aperture direction, the volumetric flow rate equation of the slurry within a single fracture was obtained. ; in, For the cube law, This is a correction term for yield stress. This represents the volumetric flow rate of the grout within a single fracture. The instantaneous opening of the fracture. This is the difference between the initial grouting pressure and the pore water pressure within the fracture, where the pore water pressure is a fixed value. The initial grouting pressure is , The instantaneous dynamic viscosity of the slurry. This refers to the instantaneous diffusion length of the grout within the crack. This represents the initial yield stress of the slurry.

[0009] In a preferred embodiment, after constructing the slurry volumetric flow rate equation, the difference between the slurry mass flowing into and out of the porous medium micro-element per unit time is equal to the rate of change of slurry mass within the micro-element, and a continuity equation is constructed: ; in, The porosity of the bedrock porous medium. The density of the slurry, Let be the velocity vector of the slurry permeation in the porous medium. This refers to the grouting time; In a preferred embodiment, based on the linear relationship between seepage velocity and hydraulic gradient, and the low-velocity laminar flow of slurry in an isotropic porous medium, the seepage motion equation is obtained: ; in, Let be the permeability tensor of the porous bedrock medium. The instantaneous dynamic viscosity of the slurry. The pore water pressure within the porous medium has a fixed initial value. , It is the acceleration due to gravity. The water head height at the location of the grouting project is determined by the water head height during the testing process and is not a fixed value. The velocity vector of the slurry seeping into the porous media domain of the bedrock; Based on the law of conservation of fluid mass, the flow rate of slurry per unit time from the fracture flow domain through the wall into the porous bedrock medium domain is taken as a constant value, along with the slurry inflow rate received by the porous medium domain at the interface, thus obtaining the flow continuity equation for the coupled dual flow domains: ; in, The seepage flow rate per unit length of fracture wall surface. The normal permeation velocity of the slurry at the dual-domain interface is given. This refers to the instantaneous diffusion length of the grout within the crack. The permeability coefficient of the porous bedrock medium. The instantaneous dynamic viscosity of the slurry. This represents the gradient of the grouting pressure within the fracture along the interface normal. This represents the gradient of pore water pressure within the fracture along the interface normal.

[0010] In a preferred embodiment, S200 derives the stress continuity equation based on the rock mass stress balance principle: ; in, The total normal stress at the interface between the two domains. The grouting pressure within the fracture flow domain. The effective normal stress at the interface of the porous bedrock medium domain; The bedrock porous media domain parameters, fracture flow domain parameters, and slurry time-varying characteristic parameters from the dual-domain parameter database obtained in S100 are substituted into a coupled dynamic model including the slurry volumetric flow rate equation, seepage motion equation, and flow continuity equation. Finite element numerical solutions are then used. Please refer to the appendix. Figure 4 This is a schematic diagram of the finite element model. The transient solution is performed with the grouting time as the step size, outputting the instantaneous crack diffusion length in the crack flow domain at different grouting times. , fracture aperture slurry volumetric flow rate Grouting pressure distribution, as well as the grout penetration range and pore water pressure in the porous bedrock medium domain. Permeation velocity Wall permeation flow Effective normal stress And the spatiotemporal distribution results of the slurry field.

[0011] In a preferred embodiment, S300 extracts the critical grouting pressure for fracture initiation corresponding to each group of tests in the orthogonal experiment, and calculates the critical grouting pressure for fracture initiation and the initial grouting pressure at the orifice for each group of tests. The ratio is used to obtain the first ratio data; The arithmetic mean of all the first ratio data is taken, and the average value is used as the high grouting pressure threshold. ; Then, extract the effective critical grouting pressure for each group of tests, and calculate the effective critical grouting pressure and the initial grouting pressure at the orifice for each group of tests. The ratio of the two values ​​is used to obtain a second ratio data, and the average value of the second ratio data is taken as the low grouting pressure threshold. The physical meaning of this threshold is that when the grouting pressure is below this threshold, crack propagation has stopped, and the grout can only permeate and diffuse in the porous medium, which is the outer boundary of the permeation-dominant zone. The wall permeation flow rate in each orthogonal experiment With slurry volume flow rate The ratio of these ratios is used as the flow distribution coefficient, and the flow distribution coefficients corresponding to all orthogonal experiments are used as the flow distribution coefficients. Interquartile statistics were performed, and the lower quartile was used as the low permeability threshold. The upper quartile was used as the high permeability threshold. ; The grouting site to be analyzed is further divided into the following specific sections: There are instances where the grouting pressure is greater than or equal to the high grouting pressure threshold. And flow allocation coefficient Less than the high permeability flow threshold The area, as the core area of ​​the fracturing channel, is where the slurry mainly flows through the fracturing and expansion of the fractures, with negligible wall penetration, and is the main channel for slurry transport. There are instances where the grouting pressure is greater than or equal to the low grouting pressure threshold. And less than the high grouting pressure threshold Flow distribution coefficient Greater than or equal to the low permeability flow threshold And less than or equal to the high permeability flow threshold The region, as the fracturing-permeability synergistic transition zone, is where fracture fracturing and pore wall permeation occur simultaneously and have comparable intensity, making it the core region of the synergistic effect. There is a grouting pressure lower than the low grouting pressure threshold. And flow allocation coefficient Greater than the low permeability flow threshold The region, as a concentrated pore permeation zone, is where crack propagation has ceased, and the slurry only permeates and diffuses within the porous medium; it is the peripheral region for slurry diffusion.

[0012] In a preferred embodiment, step S300 extracts the core region of the divided split channel, including the total length of the fracture. The characteristic parameters; The average permeation flow rate at the wall surface was extracted from the divided fracturing-permeability transition zone. The characteristic parameters; Extract the maximum diffusion radius of the concentrated permeable zone after dividing the pores. The characteristic parameters; The instantaneous diffusion length of the crack was calculated based on the coupled dynamics model. The total length of the fractures in the core area of ​​the split channel The ratio of the two values ​​is used as the crack propagation matching coefficient. : ; The permeation flow rate obtained from the coupled dynamics model Average wall permeation flow rate in the fracturing-permeability transition zone The ratio of the wall permeability coefficient to the wall permeability coefficient is used as the wall permeability coefficient. : ; And according to Obtain the diffusion range uniformity coefficient ,in, The average diffusion radius of the concentrated permeability zone; Matching coefficient for crack propagation Wall permeability coefficient and diffusion range uniformity coefficient The values ​​are summed, and the normalized value obtained is used as the comprehensive evaluation index value. After the index system is completed, the percentage value of the comprehensive evaluation index value is used as the quantitative value of the diffusion effect. .

[0013] This invention also provides a quantitative analysis system for the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock, including: Dual-domain parameter acquisition and database construction module; used to conduct parameter tests on the fracture flow domain and the porous bedrock medium domain of water-rich soft rock grouting, and obtain time-varying grout parameters by combining orthogonal experiments, classify and store the test parameters, and build a callable dual-domain parameter basic database; The coupled dynamics model construction and numerical solution module is used to establish a coupled dynamics model that includes the slurry volume flow rate equation, seepage motion equation, flow continuity equation and stress continuity equation. The parameters in the dual-domain parameter database are substituted into the model, and the transient modal solution is performed by the finite element numerical solution method. The module outputs the spatiotemporal distribution results of the slurry field, the dual-domain coupled flow distribution coefficient and the grouting parameters at different grouting times. The module for dividing and quantitatively evaluating the grouting diffusion micro-zones is used to calculate the boundary threshold of micro-zones based on parameter testing and orthogonal test results, divide the grouting diffusion micro-zones in the whole domain according to the threshold, perform characteristic quantitative calculations on the synergistic effect of each micro-zone, compare the theoretical values ​​of the coupled dynamics model with the actual quantitative parameters of the micro-zones, build a synergistic effect index system, and calculate the quantitative value of the diffusion effect.

[0014] The beneficial effects of this invention are as follows: By constructing a dual-domain coupled dynamic model that integrates the slurry volume flow rate equation, seepage motion equation, flow continuity equation, and stress continuity equation, the classical flow law is modified to adapt to the slurry yield stress characteristics. Transient analysis is achieved through finite element numerical solution, which can output the spatiotemporal distribution of the slurry field, flow distribution coefficient, and grouting parameters. Based on experimental data, the boundary threshold for micro-zone division is determined, and the entire grouting diffusion domain is divided into the core area of ​​the fracturing channel, the fracturing-permeability synergistic transition zone, and the pore concentrated permeability zone. Quantitative evaluation of the diffusion effect is achieved through feature quantification and the construction of a multi-index system. Attached Figure Description

[0015] Figure 1 This is a flowchart of the present invention; Figure 2 This example compares the time trends of the viscosity of the three slurries. Figure 3 This is a fitted curve of the permeation diffusion radius in the embodiment; Figure 4 The figure shows the fitted curve of the splitting diffusion radius in the embodiment; Figure 5 The image shown is a visual numerical simulation of the finite element method for different maximum diffusion radii in the example of the splitting and infiltration synergistic grouting diffusion effect. Detailed Implementation

[0016] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0017] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0018] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0019] As attached Figure 1-5 As shown, this embodiment provides a quantitative analysis method for the synergistic effect of grouting diffusion in water-rich soft rock fracturing and permeability, including the following steps: S100. The parameters of the fracture flow domain and the porous media domain of the bedrock in the grouting of water-rich soft rock are tested separately, and the time-varying characteristic parameters are obtained by combining orthogonal experiments. The obtained parameters are classified and stored, and a callable dual-domain parameter basic database is constructed. S100 specifically includes: Rock samples were taken using a geological drilling rig along a direction perpendicular to the rock strata, and the natural moisture content and natural density of the rock samples were tested using a drying method. After determining the particle specific gravity, the porosity is calculated using the volumetric method. In some other specific embodiments, this application drills standard cylindrical rock blocks with a diameter of 50 mm and a height of 100 mm, taking no fewer than 30 sets of samples. Parallel samples are also taken for water content and density testing. The rock blocks are placed in a triaxial permeameter, and a constant pore water pressure of 1 MPa, consistent with the engineering site, is applied. The variable head method is used to test the seepage flow rate of the rock samples under different hydraulic gradients. The permeability tensor of the bedrock porous medium is obtained by fitting the data. In the above, the original permeability characteristics parameters of water-rich soft rock are obtained, providing core parameters for the seepage control equation of porous media domain; The rock block was subjected to uniaxial compression, and its uniaxial compressive strength was obtained after the rock block failed. Elastic modulus In some other specific embodiments, this application uses an electro-hydraulic servo rock mechanics testing machine, with a loading rate set to 0.5 MPa / s until the sample fails, and the tensile strength of the rock block is obtained through a tension test. This means obtaining the basic mechanical parameters of water-rich soft rock to provide fundamental parameters for calculating surrounding rock stress and determining splitting initiation. Rock blocks with pre-fabricated fractures were prepared, and their fracture toughness was tested. The fracture toughness of the water-rich soft rock was calculated using linear elastic fracture mechanics formulas. The critical mechanical parameters for fracture initiation and propagation in water-rich soft rocks were obtained, providing core criteria for the control equation of fracture propagation. Furthermore, pore structure tests were conducted on the rock samples to obtain the fractal dimension of the pore structure. In some other specific embodiments, the pre-fabricated fracture length is 0.4 times the sample height. An electro-hydraulic servo testing machine is used for loading at a rate of 0.05 mm / min. The critical load at fracture initiation is recorded. In the pore structure test, mercury intrusion porosimetry is used to test the pore structure of the rock sample. Scanning electron microscopy images are taken, and the pore size range is 5 nm to 200 μm. The mercury intrusion volume under different intrusion pressures is recorded. Based on fractal geometry theory, the fractal dimension of the rock sample's pore structure is obtained by linearly fitting the mercury intrusion volume to the pore size under double logarithmic coordinates. ; After completing the parameter testing of the fracture flow domain, standard rock samples with original fractures were scanned using a scanner to obtain three-dimensional point cloud data of the fracture surface. The fracture aperture was calculated by fitting the normal distance of the point cloud data. The average normal distance between the two walls of the fracture is calculated using the Barton profile comparison method to obtain the surface roughness coefficient of the fracture. The purpose of this step is to accurately obtain the geometric morphology parameters of a single fracture, providing core geometric parameters for the calculation of slurry flow within the fracture. Standard rock samples with native fractures were loaded into a seepage testing apparatus to measure the seepage flow rate under different hydraulic gradients. The fracture permeability tensor was obtained by fitting the sample using a modified cubic law. The specific operation is roughly as follows: apply axial pressure and pore water pressure consistent with the field, use the constant head method to test the seepage flow of the fracture under different hydraulic gradients, and complete the parameter test of the bedrock porous media domain by fitting the modified cubic law.

[0020] The S100 also includes: Through orthogonal experiments, initial grouting pressure, grout type, and medium characteristics were used as independent variables, and grouting parameters were used as dependent variables to calibrate the experiments and obtain the initial yield stress of the grout. Instantaneous dynamic viscosity of slurry slurry density gel time , compressive strength of slurry solidified body and the permeability coefficient of the slurry solidified body ; It should be noted that while this application provides specific orthogonal experimental steps, there are equivalent experimental methods besides the orthogonal experiments disclosed in this application, which will not be elaborated upon here. These include: for designing a 3-factor, 3-level orthogonal experimental scheme, the experimental factors and levels are set as follows: initial grouting pressure Slurry viscosity, pore structure fractal dimension The fixed boundary conditions are a constant pore water pressure of 1 MPa and a constant axial pressure of 2 MPa. The pore water pressure is the preset fixed value. The viscosity of the slurry was controlled by adding 0.1%, 0.2%, and 0.3% of dimethylcyclohexylamine catalyst. The slurry matrix was a two-component slurry with a water glass-polyurethane volume ratio of 1:1 and a fractal dimension of pore structure. This corresponds to any three samples with different pore complexities in the above tests. A water glass-polyurethane two-component slurry was prepared according to the orthogonal experimental design. Different amounts of dimethylcyclohexylamine catalyst were added sequentially, and the slurry was tested using a rotational rheometer. The shear stress at the shear rate was used to obtain the initial yield stress of the slurry through linear fitting. Simultaneously, the dynamic viscosity of the slurry at different times before gelation was tested, and the time-varying viscosity curve of the slurry was plotted to obtain the instantaneous dynamic viscosity at different times. The density of the slurry was determined by testing with a hydrometer bottle. ; The inverted cup method combined with the viscosity mutation method was used to test the grouting time of grouts with different ratios. The time from the start of mixing to the loss of fluidity and the change in viscosity by an order of magnitude was recorded as the grouting time. ; Grouts with different proportions were poured into standard molds and cured under standard curing conditions until the design age. The uniaxial compressive strength of the consolidated body was then tested using a testing machine. The permeability coefficient of the solidified body was tested using a variable head permeameter. ; The parameters of the porous bedrock medium domain, the parameters of the fracture flow domain, and the time-varying characteristics of the grout obtained through orthogonal experiments are classified and stored according to grouting pressure, grout type, and medium characteristics to construct a callable dual-domain parameter basic database.

[0021] In some specific implementations, the orthogonal experimental design is shown in the table below: For the water-liquid slurry under the sixth reference working condition, time-varying characteristic parameters were tested. This application used the drying method and the draining method for testing. The average value of the three parallel samples was taken. The measured and calculated results are as follows: natural moisture content is 18.2%, natural density is 2.35 g / cm³, and particle specific gravity is 2.70 g / cm³. The porosity was obtained using the conventional rock mechanics formula (1-2.35 / 2.70)×100%≈13.0%. Then, the variable head method was used to load the rock sample into a triaxial permeameter, apply a constant pore water pressure of 1MPa and a confining pressure of 2MPa, and test the seepage flow rate under hydraulic gradients i=2, 5, 8, 10 and 15. Each gradient was tested 3 times and the average value was taken.

[0022] Based on Darcy's Law Where A is the cross-sectional area of ​​the sample, A=πd² / 4≈19.635cm², and L is the sample height of 10cm. The permeability tensor km=3.2×10^-6cm / s is obtained by fitting.

[0023] Then, mechanical property parameter tests were conducted. After setting the loading rate of the electro-hydraulic servo testing machine to 0.5MPa / s, the measured uniaxial compressive strength was 12.8MPa and the elastic modulus was 2.1GPa. The measured tensile strength was 0.92MPa after passing the Brazilian splitting tension test.

[0024] A standard specimen with a pre-fabricated crack length of 40 mm was prepared. The loading rate was 0.05 mm / min. The measured critical load for crack initiation was 8.5 kN. The fracture toughness was calculated to be approximately 0.62 MPa·m^0.5 using the three-point bending beam formula. Finally, the pore size range of 5 nm to 200 μm was tested by mercury porosimetry. Based on fractal geometry theory, the fractal dimension of the pore structure was obtained as D = 2.68.

[0025] Standard rock samples with native fractures were taken, and 3D laser scanning was used to acquire three-dimensional point cloud data of the fracture surface. The average fracture aperture was calculated to be 0.28 mm. The surface roughness coefficient was determined to be 8.2 using the Barton profile comparison method. The rock samples with native fractures were loaded into a seepage test apparatus, and the seepage flow rate under different hydraulic gradients was tested using the constant head method. The fracture permeability tensor was obtained as 4.5 × 10⁻² cm / s using the modified cubic law. Finally, through orthogonal experiments, the initial yield stress of the rock sample in this embodiment was determined to be 1.28 Pa, and the initial instantaneous dynamic viscosity was [missing value]. The grout density is 1.18 g / cm³, the grouting time (gel time) is 620 s, the compressive strength of the solidified body is 18.6 MPa, and the permeability coefficient of the solidified body is 2.1 × 10^-8 cm / s.

[0026] Based on the above methods, the complete measured and calculated results of the 9 sets of experiments are as follows: Table 2 S200. Establish a coupled dynamic model of rock pore seepage and pressure fracturing, including the slurry volumetric flow rate equation, seepage motion equation, and flow continuity equation. Then, use the finite element method to substitute parameters from the dual-domain parameter database into the obtained coupled dynamic model for modal analysis, obtaining the spatiotemporal distribution of the slurry field and the flow distribution coefficient of the dual-domain coupling. Grouting parameters at different grouting times; In grouting engineering, the flow of grout within rock fissures is the core process of grout diffusion. However, the commonly used classical cubic law only applies to laminar flow of fluid within fissures of smooth parallel plates. Once the shear stress of the grout within the fissure exceeds the initial yield stress, flow occurs, and the classical cubic law cannot accurately describe this flow. Furthermore, the roughness of the original fissures in water-rich soft rock adds additional resistance to grout flow. Therefore, this application further modifies the cubic law, S200 including: Based on the initial yield stress of the obtained slurry With the instantaneous dynamic viscosity of the slurry Same slurry shear rate The sum of the products represents the shear stress of the slurry. : ; The single fracture in the rock sample was simplified into two parallel smooth plates, and the flow of slurry within the fracture was considered as one-dimensional laminar flow. The velocity distribution equation of the slurry within the fracture was derived. Then, by integrating the velocity distribution along the fracture aperture direction, the volumetric flow rate equation of the slurry within a single fracture was obtained. ; in, The cubic law describes the relationship between the flow rate of a fluid in a fracture in a parallel plate and the fracture aperture, pressure difference, viscosity, and diffusion length, where the fracture aperture... The cubic term reflects the strong sensitivity of fracture aperture to grout flow rate. This is the yield stress correction term. Its physical meaning is that when the shear stress within the crack is less than the initial yield stress of the grout, the grout will not flow; only when the shear stress is less than the initial yield stress will the grout flow. At that time, the slurry will only produce effective flow if the correction term is greater than 0. This represents the volumetric flow rate of the grout within a single fracture. The instantaneous opening of the fracture. This is the difference between the initial grouting pressure and the pore water pressure within the fracture, where the pore water pressure is a fixed value. The initial grouting pressure is , The instantaneous dynamic viscosity of the slurry. This refers to the instantaneous diffusion length of the grout within the crack. This represents the initial yield stress of the slurry.

[0027] After constructing the slurry volumetric flow rate equation, S200 equates the difference between the slurry mass flowing into and out of the porous medium micro-element per unit time to the rate of change of slurry mass within the micro-element, and constructs a continuity equation: ; in, The porosity of the bedrock porous medium. The density of the slurry, Let be the velocity vector of the slurry permeation in the porous medium. This refers to the grouting time.

[0028] Based on the linear relationship between seepage velocity and hydraulic gradient, and the low-velocity laminar flow of slurry in isotropic porous media, S200 obtains the seepage motion equation: ; in, Let be the permeability tensor of the porous bedrock medium. The instantaneous dynamic viscosity of the slurry. The pore water pressure within the porous medium has a fixed initial value. , It is the acceleration due to gravity. The water head height at the location of the grouting project is determined by the water head height during the testing process and is not a fixed value. The velocity vector of the slurry seeping into the porous media domain of the bedrock; It should also be noted that, based on the principle of rock mass static equilibrium, porous rock masses under their own weight and grouting pressure must satisfy the stress balance equation to ensure the stress balance of the rock mass: ; Since the total stress of the rock mass is borne by both the effective stress and the pore water pressure, and the effective stress is the core physical quantity controlling the deformation and strength of the rock mass, the constitutive equation for the effective stress is derived as follows: ; For the normal force at the interface of two domains, the above tensor equation is simplified to a one-dimensional normal equation, yielding the formula for calculating the effective normal stress at the interface: ; in, This represents the total stress tensor of the rock mass. The natural density of water-rich soft rock, It is a vertically downward unit direction vector, dimensionless. For the effective stress tensor of the porous bedrock medium domain, The effective normal stress at the interface between the porous bedrock medium domain and the fractured flow domain. The pore water pressure within the porous medium. It is a second-order unit tensor, dimensionless. The total normal stress at the interface between the two domains is determined by the engineering geostress conditions. Based on the law of conservation of fluid mass, the flow rate of slurry per unit time from the fractured flow domain through the wall into the porous bedrock medium domain is defined as constant, along with the slurry inflow rate received by the porous medium domain at the interface. Specifically, since the fractured flow domain and the porous bedrock medium domain form a material exchange interface through the fracture wall, to ensure mass conservation during slurry flow between the two domains, the volumetric flow rate of slurry per unit time per which permeates from the fracture wall into the surrounding rock must be constant. Therefore, the following definition is used: Let be the unit normal vector of the interface perpendicular to the fracture wall and pointing from the fracture domain to the porous medium domain. The normal flow velocity of the slurry at the interface is . And the flow continuity equation for the two-basin coupling is obtained: ; in, The seepage flow rate per unit length of fracture wall surface. The normal permeation velocity of the slurry at the dual-domain interface is given. This refers to the instantaneous diffusion length of the grout within the crack. The permeability coefficient of the porous bedrock medium. The instantaneous dynamic viscosity of the slurry. This represents the gradient of the grouting pressure within the fracture along the interface normal. This represents the gradient of pore water pressure within the fracture along the interface normal.

[0029] According to the principle of rock mass stress balance, the total normal stress at the interface of the two domains must remain continuous. The grouting pressure within the fracture will offset part of the effective stress in the surrounding rock, thus affecting the fracture propagation and the deformation of the surrounding rock. Therefore, the stress continuity equation is derived: in, The total normal stress at the interface between the two domains. The grouting pressure within the fracture flow domain. The effective normal stress at the interface of the porous bedrock medium domain; The bedrock porous media domain parameters, fracture flow domain parameters, and slurry time-varying characteristic parameters from the dual-domain parameter database obtained in S100 are substituted into a coupled dynamic model including the slurry volumetric flow rate equation, seepage motion equation, and flow continuity equation. Finite element numerical solutions are then used. Please refer to the appendix. Figure 4This is a schematic diagram of the finite element model. The transient solution is performed with the grouting time as the step size, outputting the instantaneous crack diffusion length in the crack flow domain at different grouting times. , fracture aperture slurry volumetric flow rate Grouting pressure distribution, as well as the grout penetration range and pore water pressure in the porous bedrock medium domain. Permeation velocity Wall permeation flow Effective normal stress And the spatiotemporal distribution results of the slurry field.

[0030] In summary, in the specific implementation of S100 above, the parameters in the constructed dual-domain parameter base database were obtained. Then, using Bingham fluid constitutive model and substituting the obtained specific parameter values, the fracture aperture is 2.8×10^-4m, the initial grouting pressure and pore water pressure difference is 4MPa-1MPa=3×10^6Pa, and the initial diffusion length is 0.05m.

[0031] Substitution If the correction term is greater than 0, the slurry meets the conditions for starting flow.

[0032] Then, the initial volumetric flow rate is calculated: Cube law term: ; Square of correction term: ; Final initial volumetric flow rate: ; Based on the law of conservation of mass, a continuity equation for seepage in porous media is constructed. Based on the modified Darcy's law, the seepage motion equation is constructed: ; Where: km = 3.2 × 10^-8 m / s, initial pore water pressure P m =1×10^6Pa, taking the center of the grouting hole as the reference surface h=0, g=9.8m / s², ρ=1180kg / m³; the initial interface normal seepage velocity vn≈16m / s.

[0033] Based on the principle of fluid mass conservation, a flow continuity equation for the fracture-porous medium dual-domain interface is constructed: The final initial time was calculated as follows .

[0034] According to In the formula: P is the total normal stress at the interface (taken as the in-situ stress of 2 MPa). fWith a grouting pressure of 4 MPa in the fissure, the effective normal stress at the interface σm' is calculated to be 2 MPa.

[0035] Then, using COMSOL Multiphysics software, a two-dimensional axisymmetric model was established with a grouting hole radius of 0.05m, a computational domain radius of 20m and a height of 10m. The model was divided into a fissure flow domain and a bedrock porous medium domain, and a free triangular mesh was used with a minimum element size of 0.01m and a maximum element size of 0.5m.

[0036] Transient solution, time step Δt = 10s, total solution time 600s (close to the slurry gelation time), fully coupled flow module, solid mechanics module, seepage module, substituted with all parameters from the S100 database, as shown in the table below: Table 3 Simultaneously, the spatiotemporal distribution results of the grout field were output: at the end of 600s grouting, the grout diffusion length in the fracture domain was 7.68m, the maximum permeation radius of the grout in the bedrock porous medium domain was 1.22m, and the grouting pressure decreased from 4MPa in the grouting hole to 1MPa at the diffusion boundary, which conforms to the evolution law of fracturing-permeability synergistic grouting, and the S200 full process was completed.

[0037] S300. Based on the parameter test results obtained in S100, the boundary threshold for micro-region division is calculated and determined. The entire grouting diffusion micro-region is divided according to the boundary threshold. The synergistic effect of each micro-region is quantified to obtain the synergistic effect characteristic quantification parameters of each micro-region. The theoretical values ​​obtained based on the coupled dynamics model are compared with the actual values ​​in the synergistic effect characteristic quantification parameters of each micro-region to construct an index system with synergistic effect and obtain the quantification value of diffusion effect.

[0038] S300 extracts the critical grouting pressure for fracture initiation for each group of orthogonal experiments, and calculates the critical grouting pressure for fracture initiation and the initial grouting pressure at the orifice for each group of experiments. The ratio is used to obtain the first ratio data; The arithmetic mean of all the first ratio data is taken, and the average value is used as the high grouting pressure threshold. The physical meaning of this threshold is that when the grouting pressure is higher than this threshold, the main function of the grout is to promote the splitting and propagation of the cracks, which is the inner boundary of the splitting-dominant zone. Then, extract the effective critical grouting pressure for each group of tests, which is the minimum grouting pressure required for stable permeation of the grout in the porous medium. Calculate the effective critical grouting pressure and the initial grouting pressure at the wellhead for each group of tests. The ratio of the two values ​​is used to obtain a second ratio data, and the average value of the second ratio data is taken as the low grouting pressure threshold. The physical meaning of this threshold is that when the grouting pressure is below this threshold, the crack propagation has stopped, and the grout can only permeate and diffuse in the porous medium, which is the outer boundary of the permeation-dominant zone; The wall permeation flow rate in each orthogonal experiment With slurry volume flow rate The ratio of these values ​​is used as the flow distribution coefficient to characterize the flow distribution ratio between axial flow within the fracture and normal seepage through the wall. The flow distribution coefficients corresponding to all orthogonal experiments are then used. Interquartile statistics were performed, and the lower quartile was used as the low permeability threshold. The upper quartile was used as the high permeability threshold. ; The grouting site to be analyzed is further divided into the following specific sections: There are instances where the grouting pressure is greater than or equal to the high grouting pressure threshold. And flow allocation coefficient Less than the high permeability flow threshold The area, as the core area of ​​the fracturing channel, is where the slurry mainly flows through the fracturing and expansion of the fractures, with negligible wall penetration, and is the main channel for slurry transport. There are instances where the grouting pressure is greater than or equal to the low grouting pressure threshold. And less than the high grouting pressure threshold Flow distribution coefficient Greater than or equal to the low permeability flow threshold And less than or equal to the high permeability flow threshold The region, as the fracturing-permeability synergistic transition zone, is where fracture fracturing and pore wall permeation occur simultaneously and have comparable intensity, making it the core region of the synergistic effect. There is a grouting pressure lower than the low grouting pressure threshold. And flow allocation coefficient Greater than the low permeability flow threshold The region, as a concentrated pore permeation zone, is where crack propagation has ceased, and the slurry only permeates and diffuses within the porous medium; it is the peripheral region for slurry diffusion.

[0039] S300 extracts the core area of ​​the divided fracture channel, including the total fracture length. The characteristic parameters; Among them, the grouting pressure attenuation coefficient The average fracture aperture is obtained by comparing the pressure reduction per unit length of the fracture with the initial grouting pressure, which characterizes the degree of pressure loss within the fracture. Instantaneous opening obtained from multiple sets of parameter tests The average flow velocity of the slurry was obtained by averaging the values ​​obtained from S200. The average permeation flow rate at the wall surface was extracted from the divided fracturing-permeability transition zone. The characteristic parameters; Extract the maximum diffusion radius of the concentrated permeable zone after dividing the pores. The characteristic parameters; The instantaneous diffusion length of the crack was calculated based on the coupled dynamics model. The total length of the fractures in the core area of ​​the split channel The ratio of the two values ​​is used as the crack propagation matching coefficient. : ; in Characterize the degree of match between the actual effect of crack propagation and the theoretical expectation; The permeation flow rate obtained from the coupled dynamics model Average wall permeation flow rate in the fracturing-permeability transition zone The ratio of the wall permeability coefficient to the wall permeability coefficient is used as the wall permeability coefficient. : ; And according to Obtain the diffusion range uniformity coefficient ,in, The average diffusion radius of the concentrated permeability zone is shown in the appendix. Figure 5 , attached Figure 5 The middle represents the maximum diffusion radius. Visualized numerical simulation plots at 6.4m, 5.4m, 4.9m, 3.6m, 2.4m, and 1.8m.

[0040] Matching coefficient for crack propagation Wall permeability coefficient and diffusion range uniformity coefficient The values ​​are summed, and the normalized value obtained is used as the comprehensive evaluation index value. After the index system is completed, the percentage value of the comprehensive evaluation index value is used as the quantitative value of the diffusion effect. .

[0041] Building upon the above, this application further utilizes other obtained coefficients, such as the ratio of slurry volumetric flow rate to the volumetric flow rate of a specific micro-region, calculated using a coupled kinetic model. These ratios are used as fourth, fifth, or other matching coefficients. A weighted sum is then performed based on all matching coefficients, and the final result can serve as a more accurate quantification of the diffusion effect. .

[0042] In some other specific embodiments of this application, as shown in the appendix Figure 3 , 4As shown, the splitting diffusion radius can also be calculated based on the dynamic model in step two and the micro-region division results in step three. and penetration diffusion radius Thus, the comprehensive theoretical diffusion radius is obtained. Then, using the actual filling range of the slurry obtained from resistivity monitoring and the influence range of the slurry obtained from pore water pressure monitoring as benchmarks, the theoretical diffusion radius is inverted and calibrated using a particle swarm optimization algorithm. The objective function is set as minimizing the mean square error, with the goal of maximizing the fit between the model calculation results and the field monitoring data. The formula is: in, The smaller the value of the objective function, the higher the matching degree. This represents the total number of resistivity monitoring points. Calculate the resistivity value for the model at the i-th monitoring point. Let be the measured resistivity value at the i-th monitoring point. This represents the total number of pore water pressure monitoring points. Calculate the pore water pressure value for the model at the j-th monitoring point. The measured pore water pressure value is the j-th monitoring point.

[0043] After initializing the algorithm, the parameters to be optimized are set as the medium permeability coefficient, fracture aperture, and slurry viscosity. The upper and lower limits of each parameter are determined by the basic database. Within the parameter value range, the initial positions and velocities of 30 particles are randomly generated. The position of each particle corresponds to a set of parameters to be optimized. The initial objective function value of each particle is calculated. The position of the particle with the smallest initial objective function value is set as the initial global optimum, and the initial position of each particle is set as the initial individual optimum. Please refer to the appendix. Figure 4 The figure shows different fracture apertures at different volumetric flow rates (60, 120, 180, 210). The fitting curve of the splitting diffusion radius at different grouting pressures corresponding to different media permeability coefficients.

[0044] Substitute the parameters corresponding to the global optimal solution obtained after stopping the iteration into the coupled dynamics model, and perform transient solution again to calculate the effective diffusion radius of the slurry after inversion calibration. .

[0045] In some other specific implementations, the arithmetic mean of Pcr / P0 from the nine experimental groups is used: The baseline P0 = 4 MPa; therefore: Similarly .

[0046] The steady flow distribution coefficients of the 9 orthogonal experiments Sort in ascending order: 0.22, 0.24, 0.25, 0.35, 0.36, 0.37, 0.48, 0.49, 0.51. Low permeability flow threshold calculated using quartile statistical methods. High permeability flow threshold .

[0047] Therefore, substituting the numerical values... ; .

[0048] Substitute the values ; ; .

[0049] Similarly, .

[0050] thus: .

[0051] This invention also provides a quantitative analysis system for the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock, including: Dual-domain parameter acquisition and database construction module; used to conduct parameter tests on the fracture flow domain and the porous bedrock medium domain of water-rich soft rock grouting, and obtain time-varying grout parameters by combining orthogonal experiments, classify and store the test parameters, and build a callable dual-domain parameter basic database; The variation patterns, differences in time-varying characteristics, and fitting trends of viscosity over time for different types of slurries, i.e., the time-varying characteristic parameters of the slurries obtained from the corresponding orthogonal experiments, are shown in the attached figure. Figure 2 As shown, the test parameters are categorized and stored, and a callable dual-domain parameter database is built. This database can intuitively present the time-varying core parameters of the slurry obtained from orthogonal experiments. It is the core foundational data visualization of the dual-domain parameter database, and further, the initial yield stress of the slurry can be obtained. Instantaneous dynamic viscosity of slurry slurry density Grouting time , compressive strength of slurry solidified body and the permeability coefficient of the slurry solidified body wait.

[0052] The coupled dynamics model construction and numerical solution module is used to establish a coupled dynamics model that includes the slurry volume flow rate equation, seepage motion equation, flow continuity equation and stress continuity equation. The parameters in the dual-domain parameter database are substituted into the model, and the transient modal solution is performed by the finite element numerical solution method. The module outputs the spatiotemporal distribution results of the slurry field, the dual-domain coupled flow distribution coefficient and the grouting parameters at different grouting times. The module for dividing and quantitatively evaluating the grouting diffusion micro-zones is used to calculate the boundary threshold of micro-zones based on parameter testing and orthogonal test results, divide the grouting diffusion micro-zones in the whole domain according to the threshold, perform characteristic quantitative calculations on the synergistic effect of each micro-zone, compare the theoretical values ​​of the coupled dynamics model with the actual quantitative parameters of the micro-zones, build a synergistic effect index system, and calculate the quantitative value of the diffusion effect. The on-site monitoring data inversion calibration module is used to collect on-site resistivity and pore water pressure monitoring data. With the goal of achieving the best fit between the model calculation value and the measured value, the particle swarm optimization algorithm is used to invert and optimize key parameters such as medium permeability coefficient, fracture aperture, and grout viscosity. The optimized parameters are then substituted into the model to solve again, completing the calibration and correction of grout diffusion radius and grouting parameters.

[0053] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0054] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0055] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0056] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0057] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0058] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0059] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A quantitative analysis method for the synergistic effect of grouting diffusion in water-rich soft rock fracturing and permeability, characterized in that, Includes the following steps: S100. The parameters of the fracture flow domain and the porous media domain of the bedrock in the grouting of water-rich soft rock are tested separately, and the time-varying characteristic parameters are obtained by combining orthogonal experiments. The obtained parameters are classified and stored, and a callable dual-domain parameter basic database is constructed. S200. Establish a coupled dynamic model including the slurry volumetric flow rate equation, seepage motion equation, and flow continuity equation. Then, use the finite element numerical solution method to substitute the parameters from the dual-domain parameter database into the obtained coupled dynamic model, perform modal solving, and obtain the spatiotemporal distribution results of the slurry field and the flow distribution coefficient of the dual-domain coupling. Grouting parameters at different grouting times; S300. Based on the parameter test results obtained in S100, the boundary threshold for micro-region division is calculated and determined. The entire grouting diffusion micro-region is divided according to the boundary threshold. The synergistic effect of each micro-region is quantified to obtain the synergistic effect characteristic quantification parameters of each micro-region. The theoretical values ​​obtained based on the coupled dynamics model are compared with the actual values ​​in the synergistic effect characteristic quantification parameters of each micro-region to construct an index system with synergistic effect and obtain the quantification value of diffusion effect.

2. The method for quantitative analysis of the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock according to claim 1, characterized in that, Specifically, S100 includes: Rock samples were taken using a geological drilling rig along a direction perpendicular to the rock strata, and the natural moisture content and natural density of the rock samples were tested using a drying method. After determining the particle specific gravity, the porosity is calculated using the volumetric method. The variable head method was used to test the seepage flow rate of rock samples under different hydraulic gradients, and the permeability tensor of the porous bedrock medium was obtained by fitting. ; The rock block was subjected to uniaxial compression, and its uniaxial compressive strength was obtained after the rock block failed. Elastic modulus The tensile strength of the rock block was obtained through tension tests. ; Rock blocks with pre-fabricated fractures were then prepared, and their fracture toughness was tested. The fracture toughness of the water-rich soft rock was calculated using linear elastic fracture mechanics formulas. The pore structure of the rock sample was tested to obtain the fractal dimension of the pore structure. ; After completing the parameter testing of the fracture flow domain, standard rock samples with original fractures were scanned using a scanner to obtain three-dimensional point cloud data of the fracture surface. The fracture aperture was calculated by fitting the normal distance of the point cloud data. The surface roughness coefficient of the fracture surface was calculated by the Barton profile comparison method. Standard rock samples with native fractures were loaded into a seepage testing apparatus to measure the seepage flow rate under different hydraulic gradients. The fracture permeability tensor was obtained by fitting the sample using a modified cubic law. Parameter testing of the bedrock porous media domain was completed.

3. The quantitative analysis method for the synergistic grouting diffusion effect of water-rich soft rock fracturing and permeability as described in claim 2, is characterized in that, The S100 further includes: Through orthogonal experiments, initial grouting pressure, grout type, and medium characteristics were used as independent variables, and grouting parameters were used as dependent variables to calibrate the experiments and obtain the initial yield stress of the grout. Instantaneous dynamic viscosity of slurry slurry density gel time , compressive strength of slurry solidified body and the permeability coefficient of the slurry solidified body ; The parameters of the porous bedrock medium domain, the parameters of the fracture flow domain, and the time-varying characteristics of the grout obtained through orthogonal experiments are classified and stored according to grouting pressure, grout type, and medium characteristics to construct a callable dual-domain parameter basic database.

4. The method for quantitative analysis of the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock according to claim 1, characterized in that, S200 includes: Based on the initial yield stress of the obtained slurry With the instantaneous dynamic viscosity of the slurry Same slurry shear rate The sum of the products represents the shear stress of the slurry. : ； The single fracture in the rock sample was simplified into two parallel smooth plates, and the flow of slurry within the fracture was considered as one-dimensional laminar flow. The velocity distribution equation of the slurry within the fracture was derived. Then, by integrating the velocity distribution along the fracture aperture direction, the volumetric flow rate equation of the slurry within a single fracture was obtained. ； in, For the cube law, This is a correction term for yield stress. This represents the volumetric flow rate of the grout within a single fracture. The instantaneous opening of the fracture. This is the difference between the initial grouting pressure and the pore water pressure within the fracture, where the pore water pressure is a fixed value. The initial grouting pressure is , The instantaneous dynamic viscosity of the slurry. This refers to the instantaneous diffusion length of the grout within the crack. This represents the initial yield stress of the slurry.

5. The quantitative analysis method for the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock according to claim 4, characterized in that, After constructing the slurry volumetric flow rate equation, S200 sets the difference between the slurry mass flowing into and out of the porous medium micro-element per unit time equal to the rate of change of slurry mass within the micro-element, and constructs a continuity equation: ； in, The porosity of the bedrock porous medium. The density of the slurry, Let be the velocity vector of the slurry permeation in the porous medium. This refers to the grouting time.

6. The quantitative analysis method for the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock according to claim 5, characterized in that, S200 then obtains the seepage motion equation based on the linear proportionality between seepage velocity and hydraulic gradient, and the low-velocity laminar flow of slurry in isotropic porous media: ； in, Let be the permeability tensor of the porous bedrock medium. The instantaneous dynamic viscosity of the slurry. The pore water pressure within the porous medium has a fixed initial value. , It is the acceleration due to gravity. The water head height at the location of the grouting project is determined by the water head height during the testing process and is not a fixed value. The velocity vector of the slurry seeping into the porous media domain of the bedrock; Based on the law of conservation of fluid mass, the flow rate of slurry per unit time from the fracture flow domain through the wall into the porous bedrock medium domain is taken as a constant value, along with the slurry inflow rate received by the porous medium domain at the interface, thus obtaining the flow continuity equation for the coupled dual flow domains: ； in, The seepage flow rate per unit length of fracture wall surface. The normal permeation velocity of the slurry at the dual-domain interface is given. This refers to the instantaneous diffusion length of the grout within the crack. The permeability coefficient of the porous bedrock medium. The instantaneous dynamic viscosity of the slurry. This represents the gradient of the grouting pressure within the fracture along the interface normal. This represents the gradient of pore water pressure within the fracture along the interface normal.

7. The method for quantitative analysis of the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock according to claim 6, characterized in that, Based on the principle of rock mass stress balance, the stress continuity equation is derived from S200: ； in, The total normal stress at the interface between the two domains. The grouting pressure within the fracture flow domain. The effective normal stress at the interface of the porous bedrock medium domain; The bedrock porous media domain parameters, fracture flow domain parameters, and grout time-varying characteristic parameters from the dual-domain parameter database obtained in S100 are substituted into a coupled dynamic model including the grout volume flow rate equation, seepage motion equation, and flow continuity equation. Finite element numerical solution is then used (see Figure 4 for a schematic diagram of the finite element model). Transient solution is performed with the grouting time as the step size, outputting the instantaneous fracture diffusion length of the fracture flow domain at different grouting times. , fracture aperture slurry volumetric flow rate Grouting pressure distribution, as well as the grout penetration range and pore water pressure in the porous bedrock medium domain. Permeation velocity Wall permeation flow Effective normal stress And the spatiotemporal distribution results of the slurry field.

8. The method for quantitative analysis of the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock according to claim 1, characterized in that, The S300 extracts the critical grouting pressure for fracture initiation for each group of orthogonal experiments, and calculates the critical grouting pressure for fracture initiation and the initial grouting pressure at the orifice for each group of experiments. The ratio is used to obtain the first ratio data; The arithmetic mean of all the first ratio data is taken, and the average value is used as the high grouting pressure threshold. ; Then, extract the effective critical grouting pressure for each group of tests, and calculate the effective critical grouting pressure and the initial grouting pressure at the orifice for each group of tests. The ratio of the two values ​​is used to obtain a second ratio data, and the average value of the second ratio data is taken as the low grouting pressure threshold. ; The wall permeation flow rate in each orthogonal experiment With slurry volume flow rate The ratio of these ratios is used as the flow distribution coefficient, and the flow distribution coefficients corresponding to all orthogonal experiments are used as the flow distribution coefficients. Interquartile statistics were performed, and the lower quartile was used as the low permeability threshold. The upper quartile was used as the high permeability threshold. ; The grouting site to be analyzed is further divided into the following specific sections: There are instances where the grouting pressure is greater than or equal to the high grouting pressure threshold. And flow allocation coefficient Less than the high permeability flow threshold The area serves as the core area of ​​the split channel; There are instances where the grouting pressure is greater than or equal to the low grouting pressure threshold. And less than the high grouting pressure threshold Flow distribution coefficient Greater than or equal to the low permeability flow threshold And less than or equal to the high permeability flow threshold The region serves as a synergistic transition zone between splitting and infiltration. There is a grouting pressure lower than the low grouting pressure threshold. And flow allocation coefficient Greater than the low permeability flow threshold The area is designated as a concentrated permeability zone.

9. The quantitative analysis method for the synergistic grouting diffusion effect of fracturing and permeability in water-rich soft rock according to claim 8, characterized in that, S300 extracts the core area of ​​the divided splitting channel, including the total length of the fracture. The characteristic parameters; The average permeation flow rate at the wall surface was extracted from the divided fracturing-permeability transition zone. The characteristic parameters; Extract the maximum diffusion radius of the concentrated permeable zone after dividing the pores. The characteristic parameters; The instantaneous diffusion length of the crack was calculated based on the coupled dynamics model. The total length of the fractures in the core area of ​​the split channel The ratio of the two values ​​is used as the crack propagation matching coefficient. : ； The permeation flow rate obtained from the coupled dynamics model Average wall permeation flow rate in the fracturing-permeability transition zone The ratio of the wall permeability coefficient to the wall permeability coefficient is used as the wall permeability coefficient. : ； And according to Obtain the diffusion range uniformity coefficient ,in, The average diffusion radius of the concentrated permeability zone; Matching coefficient for crack propagation Wall permeability coefficient and diffusion range uniformity coefficient The values ​​are summed, and the normalized value obtained is used as the comprehensive evaluation index value. After the index system is completed, the percentage value of the comprehensive evaluation index value is used as the quantitative value of the diffusion effect. .

10. A quantitative analysis system for the diffusion effect of synergistic grouting and permeability in water-rich soft rock fracturing, applied to the quantitative analysis method for the diffusion effect of synergistic grouting and permeability in water-rich soft rock as described in any one of claims 1-9, characterized in that, include: Dual-domain parameter acquisition and database construction module; The parameters of the fracture flow domain and the porous bedrock medium domain for grouting in water-rich soft rock are tested separately. The time-varying characteristics of the grout are obtained by combining orthogonal experiments. The test parameters are classified and stored, and a callable dual-domain parameter database is built. Coupled dynamics model construction and numerical solution module; This is used to establish a coupled dynamic model that includes the slurry volume flow rate equation, seepage motion equation, flow continuity equation and stress continuity equation. The parameters in the dual-domain parameter base database are substituted into the model, and the transient modal solution is performed by the finite element numerical solution method. The spatiotemporal distribution results of the slurry field, the dual-domain coupled flow distribution coefficient and the grouting parameters at different grouting times are output. Module for micro-region division and quantitative evaluation of grouting diffusion effects; This method is used to calculate the boundary threshold of micro-regions based on parameter testing and orthogonal test results, divide the grouting diffusion domain into micro-regions according to the threshold, perform characteristic quantification calculation of the synergistic effect of each micro-region, compare the theoretical values ​​of the coupled dynamics model with the actual quantification parameters of the micro-regions, build a synergistic effect index system, and calculate the quantification value of the diffusion effect.

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