A mine curtain grouting slurry diffusion method and system

Abstract

This invention discloses a method and system for diffusion of grout in mine curtain grouting, relating to the field of mine grouting technology. The diffusion method includes the following steps: constructing a stochastic three-dimensional fracture network model using multiphysics numerical simulation software; simulating the mechanical and permeability characteristics of fractured rock mass, the seepage and diffusion behavior of grout, and the grout solidification reaction by solving a set of partial differential equations under multi-field coupling; opening multiple grouting holes on the three-dimensional fracture network model, and performing grouting one by one or in groups to achieve fracture sealing and curtain overlap; evaluation index: using the overlap rate of adjacent grouting holes as an evaluation index of the grouting sealing effect to evaluate the grouting overlap effect of the three-dimensional fracture network model after orthogonal experiment; constructing an orthogonal experimental table with dispersion characteristics based on the grouting evaluation and grade classification of the simulation experiment, and analyzing the simulation experiment results using range analysis and variance analysis.

Description

Technical Field

[0001] This invention relates to the field of mine grouting technology, and in particular to a method and system for diffusion of grout in mine curtain grouting. Background Technology

[0002] With the increasing depth of mineral resource extraction, hydrogeological problems caused by groundwater are becoming increasingly severe, and water-related accidents such as water inrush and sand collapse seriously threaten the safe production of mines. Curtain grouting technology, which injects grout into rock fissures to form a continuous, low-permeability anti-seepage curtain, is currently the most important and effective means of preventing water hazards in deep mines. However, in actual grouting projects, the complex distribution of rock fissures, grouting pressure, hole spacing, grout viscosity, and hydrostatic pressure interact, making it difficult to accurately predict the grout diffusion path. This directly affects the continuity and integrity of the anti-seepage curtain, restricting the treatment effect of the grouting project. Therefore, achieving precise control of the grout diffusion process is a key problem that urgently needs to be solved in current curtain grouting projects in deep mines.

[0003] Extensive research has been conducted by scholars both domestically and internationally on the diffusion patterns of grout in fractured rock masses. Ruan Wenjun revealed the time-varying characteristics of cement-based grout viscosity through experiments, and constructed a theoretical model for single-fracture grout diffusion of stable cement-based grout by combining key influencing factors such as fracture inclination angle, azimuth angle, flow core, and hydrostatic pressure. Luo Pingping et al. derived the flow control equation of Bingham grout in a smooth, inclined single fracture of equal width based on the Navier-Stokes equation. Zhan Kaiyu et al. derived and established a single-fracture dynamic water grout diffusion model, and clarified the main control mechanism and evolution law of grout diffusion under dynamic water conditions by combining indoor experiments and numerical calculations. Liu Jian et al. used COMSOL software to establish a single flat plate fracture model and analyzed the transport and diffusion mechanism of cement grout under static and dynamic water conditions. Li Shucai et al. extended the Bingham fluid constitutive equation to a generalized form based on the power function law of viscosity time-varying properties, established a single flat plate fracture grout diffusion model, and derived the pressure distribution equation along the diffusion distance. Zhang Qingsong et al. considered the spatiotemporal variation characteristics of grout viscosity, constructed a horizontal fracture grout diffusion model, and combined it with COMSOL to construct a planar grouting model to simulate the diffusion of grout in fractures. The diffusion law was studied; Gao Shengyuan established a quantitative relationship between equivalent gap width and roughness and viscosity to reveal the mechanism of Bingham fluid diffusion in rough microcracks; Yang Ping et al. established a single-crack numerical model considering roughness based on COMSOL, and revealed the diffusion law of cement slurry in a single crack under dynamic water conditions by controlling grouting time, grouting pressure and roughness coefficient; Li Shucai et al. used COMSOL software to construct a planar crack model to simulate the flow field distribution under different initial aperture and interface potential conditions, and analyzed the influence of contact area and roughness on the slurry flow path; Zhang et al. considered the flow characteristics of slurry viscosity under spatial changes; Mu et al. established a slurry flow model with hydraulic coupling effect, and analyzed the influence of roughness and shear deformation on the slurry flow characteristics; Yan Lianghuan et al. derived the spatiotemporal distribution equation of slurry diffusion trace morphology and distance, and used COMSOL to establish an inclined single-crack grouting diffusion model to analyze the influence of grouting pressure difference, crack aperture and crack inclination angle on slurry diffusion trace morphology and diffusion distance.

[0004] The success of mine curtain grouting hinges on the effective diffusion of the grout within the target area, ensuring it fully fills the fissures and forms a complete, homogeneous curtain. However, existing research is largely limited to single fissures or idealized two-dimensional models, failing to accurately reflect the randomness and heterogeneity of the three-dimensional fissure network in mine curtain grouting. The lack of systematic analysis of the grout diffusion path and overlapping effect within the random three-dimensional fissure network makes it difficult to predict the continuity and integrity of the curtain in engineering practice. Therefore, this paper, based on a random three-dimensional fissure network model and combined with orthogonal experimental design, analyzes the influence of grouting parameters on the grout diffusion law and overlapping effect. Summary of the Invention

[0005] This solution addresses the problems and needs raised above by proposing a method and system for the diffusion of grout in mine curtain grouting. Due to the adoption of the following technical features, it can achieve the above-mentioned technical objectives and bring about several other technical effects.

[0006] One object of the present invention is to provide a method for diffusion of grout in mine curtain grouting, comprising the following steps: S10: Model Construction: A stochastic three-dimensional fracture network model is constructed using multiphysics numerical simulation software. By solving a set of partial differential equations under multi-field coupling, the mechanical and permeability characteristics of fractured rock mass, the seepage and diffusion behavior of grouting fluid, and the solidification reaction of grouting fluid are simulated. S20: Orthogonal test: Multiple grouting holes are opened on the three-dimensional fracture network model, and grouting is carried out one by one or in groups to achieve crack sealing and curtain overlap; among them, an orthogonal test scheme is adopted, and four influencing factors are selected: grouting pressure, hole spacing, grout viscosity and hydrostatic pressure, and multiple levels are set for each influencing factor; S30: Evaluation index: The overlap rate of adjacent grouting holes is used as the evaluation index of the grouting sealing effect to evaluate the grouting overlap effect of the three-dimensional fracture network model after orthogonal experiment. S40: Results Analysis: Based on the grouting evaluation and grading of the simulation test, an orthogonal experimental table with dispersion characteristics was constructed, and the results of the simulation test were analyzed by range analysis and variance analysis.

[0007] In addition, the mine curtain grouting slurry diffusion method and system according to the present invention may also have the following technical features: In one example of the present invention, step S10, constructing the random three-dimensional fracture network model specifically includes: By statistically analyzing the center point coordinates, attitude, and size measured in the field, the probability distribution function was determined. Then, Monte Carlo random sampling was used to generate a large number of virtual fractures that followed a specific distribution, which were finally combined into a three-dimensional DFN model; among which, (1) Uniform random model of crack location: The distribution of the fracture center points in all-directional space follows a uniform distribution, and its probability density function is: In the formula, , These are the maximum and minimum values ​​of the position parameter in this dimension, respectively. (2) Power-law stochastic model of crack size: In the formula, α is the power-law distribution exponent, reflecting the power-law decay characteristics of the size distribution. It is the minimum measured value of the crack length; (3) Fisher stochastic model of fracture orientation: In the formula, θ is the angular deviation of the average angle of the ellipse direction described by the probability density function of the Fisher distribution, and K is called the Fisher diffusion coefficient or Fisher constant.

[0008] In one example of the present invention, in step S20, during the grouting process of the fractured rock mass, various cement-water glass two-component grouts with different viscosities are selected as the grouting fluids. All of these different grouts conform to Bingham fluid characteristics; their rheological properties include the presence of yield stress. When the shear stress is lower than When the shear stress is higher than 1, the slurry does not flow; when the shear stress is higher than 1, the slurry does not flow. At that time, the shear stress of the slurry is directly proportional to the shear rate; its rheological equation is: In the formula, For shear stress, For yield stress, For plastic viscosity, denoted as shear rate.

[0009] In one example of the present invention, in step S20, the diffusion region formed by the diffusion of slurry includes an effective diffusion region, wherein, in the three-dimensional fracture network grouting numerical simulation of multiphysics numerical simulation software, the effective diffusion region is a region with a slurry integral number ≥ 0.5.

[0010] In one example of the invention, in step S30, the overlap rate... The calculation formula is: In the formula, This represents the average value of the overlapping volume of the effective diffusion zone of the slurry between the two holes. This represents the average effective diffusion volume of a single pore.

[0011] In one example of the present invention, in step S30, the evaluation of the grouting overlap effect includes: when the grout diffusion zone between two grouting holes fully overlaps or overlaps, the overlap rate is high, the curtain continuity is good, and it is conducive to forming a reliable anti-seepage system; conversely, if the grout diffusion range is insufficient, there are unfilled gaps or weak areas between the holes, the overlap rate is low, resulting in curtain discontinuity and causing problems such as leakage, water inrush or decreased stability of the surrounding rock.

[0012] In one example of the present invention, in step S40, the analysis of the simulation test results using range analysis and variance analysis specifically includes: single-factor analysis and interaction factor analysis of grouting pressure, hole spacing, grout viscosity, and hydrostatic pressure. The interaction factor analysis includes the following: When the hole spacing is constant, the overlap rate increases with the increase of grouting pressure. As the spacing of grouting holes increases, the drilling position may avoid key fractures, which directly affects whether the grout can effectively fill the key water-conducting fractures, thus affecting the final overlap rate. The change in grout viscosity has no significant effect on the grouting overlap effect; When the hydrostatic pressure is constant, the overlap rate increases significantly with the increase of grouting pressure; conversely, when the grouting pressure is constant, the overlap rate decreases with the increase of hydrostatic pressure. Low-viscosity grout has good fluidity. When the spacing between grouting holes is small, it is easy to spread fully in the crack and achieve overlap. However, when the spacing between grouting holes is large, the grout filling path increases, and the grout is prone to viscosity and energy consumption during diffusion, which weakens the overlapping effect. When the hydrostatic pressure is constant, the grouting overlap rate gradually increases as the hole spacing decreases; when the hole spacing is constant, the grouting overlap rate gradually increases as the hydrostatic pressure decreases. Under low hydrostatic pressure, low-viscosity slurry easily diffuses and fills tiny cracks, improving the overlap rate; while under high hydrostatic pressure, the effect of slurry viscosity is masked.

[0013] Another object of the present invention is to provide a grout diffusion system for mine curtain grouting, comprising: The model building module is configured to build a stochastic three-dimensional fracture network model using multiphysics numerical simulation software. By solving a set of partial differential equations under multi-field coupling, it simulates the mechanical and permeability characteristics of fractured rock mass, the seepage and diffusion behavior of grouting fluid, and the solidification reaction of grouting fluid. The orthogonal test module is configured to open multiple grouting holes on a three-dimensional fracture network model, and perform grouting one by one or in groups to achieve crack sealing and curtain overlap. The orthogonal test scheme is adopted, and four influencing factors are selected: grouting pressure, hole spacing, grout viscosity and hydrostatic pressure, and multiple levels are set for each influencing factor. The evaluation index module is configured to use the overlap rate of adjacent grouting holes as an evaluation index of the grouting sealing effect to evaluate the grouting overlap effect of the three-dimensional fracture network model after orthogonal experiment. The results analysis module is configured to construct an orthogonal experimental table with dispersion characteristics for grouting evaluation and grading based on simulation tests, and to analyze the simulation test results using range analysis and variance analysis.

[0014] In one example of the present invention, during the grouting process of fractured rock mass, various cement-water glass two-component grouts with different viscosities are selected as the grouting fluids. All of these different grouts conform to Bingham fluid characteristics; their rheological properties include the presence of yield stress. When the shear stress is lower than When the shear stress is higher than 1, the slurry does not flow; when the shear stress is higher than 1, the slurry does not flow. At that time, the shear stress of the slurry is directly proportional to the shear rate; its rheological equation is: In the formula, For shear stress, For yield stress, For plastic viscosity, denoted as shear rate.

[0015] In one example of the invention, the overlap rate The calculation formula is: In the formula, This represents the average value of the overlapping volume of the effective diffusion zone of the slurry between the two holes. This represents the average effective diffusion volume of a single pore.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention constructs a realistic three-dimensional fracture network model of the mining area, systematically conducts multi-factor coupling analysis, and introduces the overlap rate as a quantitative evaluation index, realizing high-fidelity simulation and scientific evaluation of the diffusion process and effect of curtain grouting, providing theoretical basis and decision support for the design of mine curtain grouting projects.

[0017] The order of influence of various factors on the overlap rate in this invention is: grouting pressure > hole spacing > hydrostatic pressure > grout viscosity. Range analysis showed that the range of grouting pressure reached 19.61%, making it the main controlling factor. Analysis of variance further confirmed that the effects of grouting pressure, hole spacing, and hydrostatic pressure were highly significant, while grout viscosity had no significant effect within the experimental range. Interaction analysis indicated that the combination of low hydrostatic pressure and small hole spacing significantly improved the overlap rate, while high grouting pressure could compensate for the decrease in overlap rate caused by increased hole spacing.

[0018] The preferred embodiments of the invention will be described in more detail below with reference to the accompanying drawings, so as to facilitate an understanding of the features and advantages of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. The drawings are merely illustrative of some embodiments of the present invention and are not intended to limit the scope of the present invention to all embodiments.

[0020] Figure 1 A flowchart illustrating the slurry diffusion method for mine curtain grouting according to an embodiment of the present invention; Figure 2 This is a hydrogeological plan of the study area in this application according to an embodiment of the present invention; Figure 3 This is a random three-dimensional fracture network diagram according to an embodiment of the present invention; Figure 4 The following are grout diffusion diagrams for three-dimensional fracture network grouting according to embodiments of the present invention: (a. Grout diffusion morphology diagram of XZ section of test No. 15 (A4B3C2D4); b. Grout diffusion morphology diagram of XZ section of test No. 1 (A1B1C1D1); c. Grout diffusion morphology diagram of test No. 15 (A4B3C2D4) at 30 min; d. Grout diffusion morphology diagram of test No. 1 (A1B1C1D1) at 30 min). Figure 5 This is a volume distribution diagram of the effective diffusion of grout at a grouting pressure of 3 MPa according to an embodiment of the present invention.

[0021] Figure 6 This is a diagram showing the effective diffusion volume distribution of grout at a grouting pressure of 4 MPa according to an embodiment of the present invention. Figure 7 This is a diagram showing the effective diffusion volume distribution of grout at a grouting pressure of 5 MPa according to an embodiment of the present invention. Figure 8 This is a diagram showing the effective diffusion volume distribution of grout at a grouting pressure of 6 MPa according to an embodiment of the present invention. Figure 9 This is a trend chart of the average overlap rate of each factor according to an embodiment of the present invention; Figure 10 The diagram shows the overlapping effect under the interaction of grouting pressure and hole spacing according to an embodiment of the present invention (a. three-dimensional surface view; b. contour map). Figure 11 The diagram shows the overlapping effect under the interaction of grouting pressure and grout viscosity according to an embodiment of the present invention (a. three-dimensional surface diagram; b. contour map). Figure 12 The diagram shows the overlapping effect under the interaction of grouting pressure and hydrostatic pressure according to an embodiment of the present invention (a. three-dimensional surface view; b. contour map). Figure 13 The diagram shows the overlapping effect of slurry viscosity and hole spacing according to an embodiment of the present invention (a. three-dimensional surface view; b. contour map). Figure 14 The diagram shows the overlapping effect under the interaction of hydrostatic pressure and hole spacing according to an embodiment of the present invention (a. three-dimensional surface view; b. contour map). Figure 15 The diagram shows the overlapping effect under the interaction of hydrostatic pressure and slurry viscosity according to an embodiment of the present invention (a. three-dimensional surface diagram; b. contour map). Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, “an” or “a” and similar terms do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0024] Current mine curtain grouting engineering designs often rely on past experience or recommended parameters from specifications, making it difficult to quantitatively analyze the coupling effects of fracture network structure, grout rheological properties, and groundwater environment in a specific mining area. This often leads to insufficient compatibility between design parameters and on-site geological conditions: being too conservative significantly increases engineering costs, while being too aggressive makes it difficult to form a continuous curtain. Furthermore, traditional methods typically analyze the influence of single factors in isolation, while in actual engineering, there are significant interactive effects between factors such as grouting pressure, hole spacing, grout viscosity, and hydrostatic pressure. Ignoring these coupling effects can easily lead to a failure to synergistically optimize parameter combinations, or even mutual inhibition.

[0025] According to a first aspect of the present invention, a method for diffusion of grout in a mine curtain grouting system is provided, such as... Figure 1 As shown, it includes the following steps: S10: Model Construction: A stochastic three-dimensional fracture network model is constructed using multiphysics numerical simulation software. By solving a set of partial differential equations under multi-field coupling, the mechanical and permeability characteristics of fractured rock mass, the seepage and diffusion behavior of grouting fluid, and the solidification reaction of grouting fluid are simulated. S20: Orthogonal Experiment: Multiple grouting holes are opened on the three-dimensional fracture network model, and grouting is carried out individually or in groups to achieve crack sealing and curtain overlap; among them, an orthogonal experimental scheme (e.g., L) is adopted. 16 Four influencing factors were selected: grouting pressure, hole spacing, grout viscosity, and hydrostatic pressure. Multiple levels were set for each influencing factor. S30: Evaluation index: The overlap rate of adjacent grouting holes is used as the evaluation index of the grouting sealing effect to evaluate the grouting overlap effect of the three-dimensional fracture network model after orthogonal experiment. S40: Results Analysis: Based on the grouting evaluation and grading of the simulation test, an orthogonal experimental table with dispersion characteristics was constructed, and the results of the simulation test were analyzed by range analysis and variance analysis.

[0026] The present invention has the following beneficial effects: This diffusion method constructs a realistic three-dimensional fracture network model of the mining area, systematically analyzes the coupling effects of multiple factors, and introduces the overlap rate as a quantitative evaluation index. It achieves high-fidelity simulation and scientific evaluation of the diffusion process and effect of curtain grouting slurry, providing theoretical basis and decision support for the design of mine curtain grouting projects.

[0027] The order of influence of various factors on the overlap rate in this diffusion method is: grouting pressure > hole spacing > hydrostatic pressure > grout viscosity. Range analysis showed that the range of grouting pressure reached 19.61%, making it the main controlling factor. Analysis of variance further confirmed that the effects of grouting pressure, hole spacing, and hydrostatic pressure were highly significant, while grout viscosity had no significant effect within the experimental range. Interaction analysis indicated that the combination of low hydrostatic pressure and small hole spacing significantly improved the overlap rate, while high grouting pressure could compensate for the decrease in overlap rate caused by increased hole spacing.

[0028] In one example of the present invention, step S10, constructing the random three-dimensional fracture network model specifically includes: By statistically analyzing the center point coordinates, attitude, and size measured in the field, the probability distribution function was determined. Then, Monte Carlo random sampling was used to generate a large number of virtual fractures that followed a specific distribution, which were finally combined into a three-dimensional DFN model; among which, (1) Uniform random model of crack location: The distribution of the fracture center points in all-directional space follows a uniform distribution, and its probability density function is: In the formula, , These are the maximum and minimum values ​​of the position parameter in this dimension, respectively. (2) Power-law stochastic model of crack size: In the formula, α is the power-law distribution exponent, reflecting the power-law decay characteristics of the size distribution. It is the minimum measured value of the crack length; (3) Fisher stochastic model of fracture orientation: In the formula, θ is the angular deviation of the average angle of the ellipse direction described by the probability density function of the Fisher distribution, and K is called the Fisher dispersion coefficient or Fisher constant, which characterizes the degree of concentration of the fracture direction relative to the average direction. The larger K is, the more concentrated the direction distribution.

[0029] In one example of the present invention, during the grouting process in fractured rock mass in step S20, the rheological properties of the grout significantly affect its seepage diffusion path and sealing effect in the fracture network. Based on the relationship between shear stress and shear rate, commonly used grouts can be classified into three categories: Newtonian fluids, Bingham fluids, and power-law fluids. The grout used in the Banba lead-zinc mine is a cement-water glass two-component grout, the viscosity of which is affected by factors such as water-cement ratio, temperature, and water glass modulus. The initial viscosity is typically 0.1 Pa s to 1 Pa s at low water-cement ratios and low water glass content. This paper selects four cement-water glass two-component grouts with different viscosities (0.6 Pa s, 0.7 Pa s, 0.8 Pa s, and 0.9 Pa s) as the grout to be injected. All four grouts with different viscosities conform to the characteristics of Bingham fluids; their rheological properties include the presence of yield stress. When the shear stress is lower than When the shear stress is higher than 1, the slurry does not flow; when the shear stress is higher than 1, the slurry does not flow. At that time, the shear stress of the slurry is directly proportional to the shear rate; its rheological equation is: In the formula, The stress is the shear stress (Pa). The yield stress is (Pa). It is the plastic viscosity (Pa·s). Shear rate (s) -1 ).

[0030] In one example of the present invention, in step S20, the diffusion region formed by the slurry diffusion includes an effective diffusion region. In the three-dimensional fracture network grouting numerical simulation of the multiphysics numerical simulation software COMSOL, the effective diffusion region is a region with a slurry volume fraction ≥ 0.5 in order to extract the volume of the effective diffusion region of the slurry.

[0031] In one example of the invention, in step S30, the overlap rate... The calculation formula is: In the formula, This represents the average value of the overlapping volume of the effective diffusion zone of the slurry between the two holes. This represents the average effective diffusion volume of a single pore.

[0032] In one example of the present invention, in step S30, the evaluation of the grouting overlap effect includes: when the grout diffusion zone between two grouting holes fully overlaps or overlaps, the overlap rate is high, the curtain continuity is good, and it is conducive to forming a reliable anti-seepage system; conversely, if the grout diffusion range is insufficient, there are unfilled gaps or weak areas between the holes, the overlap rate is low, resulting in curtain discontinuity and causing problems such as leakage, water inrush or decreased stability of the surrounding rock.

[0033] In one example of the present invention, in step S40, the analysis of the simulation test results using range analysis and variance analysis specifically includes: single-factor analysis and interaction factor analysis of grouting pressure, hole spacing, grout viscosity, and hydrostatic pressure. The interaction factor analysis includes the following: When the hole spacing is constant, the overlap rate increases with the increase of grouting pressure. As the spacing of grouting holes increases, the drilling position may avoid key fractures, which directly affects whether the grout can effectively fill the key water-conducting fractures, thus affecting the final overlap rate. The change in grout viscosity has no significant effect on the grouting overlap effect; When the hydrostatic pressure is constant, the overlap rate increases significantly with the increase of grouting pressure; conversely, when the grouting pressure is constant, the overlap rate decreases with the increase of hydrostatic pressure. Low-viscosity grout has good fluidity. When the spacing between grouting holes is small, it is easy to spread fully in the crack and achieve overlap. However, when the spacing between grouting holes is large, the grout filling path increases, and the grout is prone to viscosity and energy consumption during diffusion, which weakens the overlapping effect. When the hydrostatic pressure is constant, the grouting overlap rate gradually increases as the hole spacing decreases; when the hole spacing is constant, the grouting overlap rate gradually increases as the hydrostatic pressure decreases. Under low hydrostatic pressure, low-viscosity slurry easily diffuses and fills tiny cracks, improving the overlap rate; while under high hydrostatic pressure, the effect of slurry viscosity is masked.

[0034] A mine curtain grouting slurry diffusion system according to a second aspect of the present invention comprises: The model building module is configured to build a stochastic three-dimensional fracture network model using multiphysics numerical simulation software. By solving a set of partial differential equations under multi-field coupling, it simulates the mechanical and permeability characteristics of fractured rock mass, the seepage and diffusion behavior of grouting fluid, and the solidification reaction of grouting fluid. The orthogonal experimental module is configured to create multiple grouting holes on a three-dimensional fracture network model, and perform grouting individually or in groups to achieve fracture sealing and curtain overlap; wherein, an orthogonal experimental scheme (e.g., L) is adopted. 16 Four influencing factors were selected: grouting pressure, hole spacing, grout viscosity, and hydrostatic pressure. Multiple levels were set for each influencing factor. The evaluation index module is configured to use the overlap rate of adjacent grouting holes as an evaluation index of the grouting sealing effect to evaluate the grouting overlap effect of the three-dimensional fracture network model after orthogonal experiment. The results analysis module is configured to construct an orthogonal experimental table with dispersion characteristics for grouting evaluation and grading based on simulation tests, and to analyze the simulation test results using range analysis and variance analysis.

[0035] This diffusion system constructs a realistic three-dimensional fracture network model of the mining area, systematically analyzes the coupling effects of multiple factors, and introduces the overlap rate as a quantitative evaluation index. It achieves high-fidelity simulation and scientific evaluation of the diffusion process and effect of curtain grouting slurry, providing theoretical basis and decision support for the design of mine curtain grouting projects.

[0036] The order of influence of various factors on the overlap rate in this diffusion system is: grouting pressure > hole spacing > hydrostatic pressure > grout viscosity. Range analysis showed that the range of grouting pressure was 19.61%, making it the main controlling factor. Analysis of variance further confirmed that the effects of grouting pressure, hole spacing, and hydrostatic pressure were highly significant, while grout viscosity had no significant effect within the experimental range. Interaction analysis indicated that the combination of low hydrostatic pressure and small hole spacing significantly improved the overlap rate, while high grouting pressure could compensate for the decrease in overlap rate caused by increased hole spacing.

[0037] In one example of the present invention, during the grouting process of fractured rock mass, various cement-water glass two-component grouts with different viscosities are selected as the grouting fluids. All of these different grouts conform to Bingham fluid characteristics; their rheological properties include the presence of yield stress. When the shear stress is lower than When the shear stress is higher than 1, the slurry does not flow; when the shear stress is higher than 1, the slurry does not flow. At that time, the shear stress of the slurry is directly proportional to the shear rate; its rheological equation is: In the formula, The stress is the shear stress (Pa). The yield stress is (Pa). It is the plastic viscosity (Pa·s). Shear rate (s) -1 ).

[0038] In one example of the invention, the overlap rate The calculation formula is: In the formula, This represents the average value of the overlapping volume of the effective diffusion zone of the slurry between the two holes. This represents the average effective diffusion volume of a single pore.

[0039] It should be noted that the mine curtain grouting slurry diffusion system of the present invention can also perform any of the processes described in the previously described mine curtain grouting slurry diffusion method, and the specific details are not repeated here.

[0040] Specific examples: Engineering geological conditions of the mining area: like Figure 2 As shown, the mining area overview and regional geological background are as follows: The Banba lead-zinc mine is located in the Banba Village area of ​​Huanjiang Maonan Autonomous County, Hechi City, Guangxi Zhuang Autonomous Region, geographically located northwest of the county seat, approximately 28 km away in a straight line. The regional strata are distributed in a north-northeast trending banded pattern. The western part mainly exposes Middle Devonian (D2) exposed carbonate rock strata, while the eastern part is dominated by Lower Carboniferous (C1) and Upper Devonian (D3) insoluble rock strata, showing significant differences in lithological assemblage. The geomorphological features are well correlated with the spatial distribution of stratigraphic lithology: the western and southwestern parts, influenced by the subtropical humid climate and carbonate karst erosion, have developed typical karst peak-cluster-valley landforms with strong topographic dissection and significant elevation differences; the eastern insoluble rock distribution area is mainly characterized by low mountains and hills with gentler slopes and relatively flat terrain. The designated mining area covers 0.3469 km². 2 According to the mineral resource development plan, the designed production scale is 6×10 4 t / a.

[0041] Hydrogeological conditions of the mining area: The Banba lead-zinc mine is located on the surface watershed between the Chuanshan River and the Shangma River. The area has a relatively developed surface water system, with rivers flowing year-round including the Gubin River, Chuanshan River, and Shangma River. Among them, the Chuanshan River has a significant impact on the water supply to the deposit. The riverbed elevation on the western side of the mining area is +265 m to +270 m, and the flow rate during the high-water season is 25 m³ / h. 3 / s, 1.3 m during the dry season 3 / s, with a maximum observed flow rate of 9.03 m³ / s in 2017. 3 / s, minimum flow rate 0.09 m³ / s 3 / s.

[0042] The exposed strata in the mining area mainly include the upper part of the Middle Devonian Donggangling Formation (D2d). 2 The bedrock strata consist of the Upper Devonian Liujiang Formation (D3l), the Lower Carboniferous (C1), and the Quaternary (Q). The bedrock strata generally trend NNE and dip SNE, with some areas dipping NE. The Quaternary strata are mainly distributed along the terraces, gullies, and foothills of the Chuanshan River. Tectonically, the mining area is located on the eastern wing of the Chuanshan anticline, exhibiting a monocline structure with gently dipping strata, underdeveloped folds, and relatively well-developed fault structures. These faults can be divided into three groups based on their strike: NNE, NNE, and near-EW. The NNE-trending fault group includes F8 and F... 45 F9, F 05 Faults, of which F8 is the main ore-controlling fault, approximately 10.6 km long and dipping at 105 km / h. ° ~103 ° Inclination angle 40 ° ~75 ° The fault band has a width of 0.4 m to 7.1 m and a displacement of 90 m to 260 m, and is classified as a normal fault. The NNE-trending fault group includes F 40 F 02 F 03 Fault, F 02 The fault is approximately 320 m long and dips at 74 degrees. ° Inclination angle 45 ° ~90 ° Karst development is present within its fracture zone; the near-east-west trending fault group includes F 01 F 04 Fault, F 01 It is the main water-conducting fault, approximately 520 m long, dipping at 25 degrees. ° Inclination angle 65 ° ~70 ° The width of the karst and fissure development zone reaches 10 m to 25 m.

[0043] The specific steps are as follows: Step 1: Constructing a stochastic three-dimensional fracture network model that accurately reflects the structural characteristics of underground rock masses is fundamental for subsequent grout diffusion simulation. This application employs COMSOL Multiphysics numerical simulation software to conduct finite element simulation studies of the grouting process in three-dimensional fractured rock masses. The software's stochastic three-dimensional fracture network plugin (Discrete Fracture Network-3D, DFN-3D) is based on Discrete Fracture Network (DFN) theory, constructing three-dimensional fractures using a stochastic distribution function and geometric parameterization method, ultimately forming an elliptical sheet-like three-dimensional fracture network that can reproduce the stochastic distribution characteristics of fractures in the rock mass. By solving a system of partial differential equations under multi-field coupling, the software can effectively simulate the mechanical and permeability characteristics of fractured rock masses, the seepage and diffusion behavior of grout, and the grout solidification reaction.

[0044] This method defines the geometric parameters of the fracture, including the coordinates of the center point, attitude, and size, as random variables. By statistically analyzing these parameters measured in the field, their probability distribution function is determined. Then, Monte Carlo random sampling is used to generate a large number of virtual fractures that follow a specific distribution, which are finally combined into a three-dimensional DFN model.

[0045] Uniform random model of crack location: The distribution of the fracture center points in all-directional space follows a uniform distribution, and its probability density function is: in: , These are the maximum and minimum values ​​of the position parameter in this dimension, respectively.

[0046] Power-law stochastic model of crack size: Where: α is the power-law distribution exponent (reflecting the power-law decay characteristics of the size distribution). It is the minimum measured value of the crack length.

[0047] Fisher stochastic model of fracture orientation: The probability density function of the Fisher distribution describes the angular deviation θ of the mean angle of the elliptical direction, where K is called the Fisher dispersion coefficient or Fisher constant, characterizing the degree of concentration of the fracture directions relative to the mean direction; the larger K is, the more concentrated the direction distribution. The final generated stochastic three-dimensional fracture network model is as follows: Figure 3 As shown.

[0048] Step 2: The purpose of curtain grouting is to form a continuous, closed grouting curtain in the underground rock mass or strata to block water, reinforce the surrounding rock, or prevent leakage. In actual construction, one or more rows of grouting holes are usually arranged at certain intervals, and grouting is performed one by one or in groups. For the three-dimensional fracture network grouting test, a single row of three grouting holes was set up, using L... 16 (4) 5 An orthogonal experimental design was adopted, selecting four influencing factors: grouting pressure (A), hole spacing (B), grout viscosity (C), and hydrostatic pressure (D). Each factor was set with four levels, which were determined based on engineering practice.

[0049] During grouting of fractured rock masses, the rheological properties of the grout significantly affect its seepage diffusion path and sealing effect within the fracture network. Based on the relationship between shear stress and shear rate, commonly used grouts can be classified into three categories: Newtonian fluids, Bingham fluids, and power-law fluids. The grout used in the Banba lead-zinc mine is a cement-water glass two-component grout. Its viscosity is affected by factors such as water-cement ratio, temperature, and water glass modulus. The initial viscosity is typically 0.1 Pa s to 1 Pa s at low water-cement ratios and low water glass content. This paper selects four cement-water glass two-component grouts with different viscosities (0.6 Pa s, 0.7 Pa s, 0.8 Pa s, and 0.9 Pa s) as the grout to be injected. All four grouts with different viscosities conform to the characteristics of Bingham fluids. Their rheological properties include the presence of yield stress. When the shear stress is lower than When the shear stress is higher than 1, the slurry does not flow; when the shear stress is higher than 1, the slurry does not flow. At this point, the shear stress of the slurry is directly proportional to the shear rate. Its rheological equation is: in: The stress is the shear stress (Pa). The yield stress is (Pa). It is the plastic viscosity (Pa·s). Shear rate (s) -1 ).

[0050] Based on the design data for curtain grouting in mining areas, which specifies a hole spacing of 10 m, four hole spacings (9 m, 10 m, 11 m, and 12 m) were selected for study. The designed hole depth was 300 m, and four hydrostatic pressures (0.5 MPa, 1 MPa, 1.5 MPa, and 2 MPa) were selected. The grouting pressure for curtain grouting in mining areas must be greater than the hydrostatic pressure, and according to the specifications, the specific value is 1.6 to 3.0 times the hydrostatic pressure. The specifications are based on a summary of engineering practice and experimental data, aiming to ensure the seepage prevention effect and engineering safety of the curtain. In practical applications, considering the short gel time of cement-water glass double-liquid grout, it is necessary to appropriately increase the pressure to ensure the diffusion range; therefore, four grouting pressures (3 MPa, 4 MPa, 5 MPa, and 6 MPa) were selected. The levels of each factor and the orthogonal experimental tables are shown in Tables 1 and 2.

[0051] Table 1. Values ​​of various factors in the orthogonal test of grouting in a three-dimensional fracture network. Table 2. Orthogonal test table for three-dimensional fracture network grouting In actual grouting projects, the complexity and lack of visibility of geological conditions make it difficult to observe the grout diffusion process. Only indirect indicators such as grouting time, grouting pressure, grouting volume, and changes in water inrush can be used as the basis for determining grouting termination. However, these indicators only macroscopically reflect the grouting construction status and cannot accurately characterize the actual diffusion law and overlap state of the grout in the fracture network. The core objectives of grouting projects are surrounding rock reinforcement and curtain water shut-off. In the COMSOL three-dimensional fracture network grouting numerical simulation test, the diffusion range, diffusion morphology, and grout overlap effect between grouting holes can be directly observed by adjusting the model transparency and transmittance. Compared to traditional indirect evaluation indicators, the overlap rate can directly quantify the degree of grout overlap in the fracture network, accurately reflecting the effectiveness of grouting and sealing. Therefore, the overlap rate can be used as the core evaluation indicator for grouting and sealing effectiveness.

[0052] The overlap ratio refers to the degree to which the grout diffusion areas of adjacent grouting holes overlap and connect with each other along the designed curtain thickness direction. A higher overlap ratio indicates better curtain continuity when the grout diffusion areas between two grouting holes fully overlap or connect. Figure 4 (a) and (c) are conducive to the formation of a reliable seepage prevention system; conversely, if the grout diffusion range is insufficient, and there are unfilled gaps or weak areas between the holes, the overlap rate will be low, resulting in discontinuity of the curtain. Figure 4 (b) and (d) may cause problems such as leakage, water inrush or decreased stability of the surrounding rock.

[0053] Overlap rate The calculation formula is: in: This represents the average value of the overlapping volume of the effective diffusion zone of the slurry between the two holes. This represents the average effective diffusion volume of a single pore.

[0054] The purpose of grouting is to achieve crack sealing and curtain overlap through grout diffusion. However, not all diffusion areas of the grout achieve effective results; therefore, it is necessary to define the effective diffusion area to delineate the core region where the grout exerts its sealing and reinforcement functions. In the COMSOL three-dimensional crack network grouting numerical simulation, to extract the volume of the effective diffusion area, the region with a grout volume fraction ≥ 0.5 is defined as the effective diffusion area. This area is the key space for the grout to fill cracks and overlap between holes, providing a basis for calculating the overlap rate and evaluating the grouting effect.

[0055] According to Table 2, a three-dimensional fracture network model was first established, and then 16 sets of simulated grouting tests were conducted on the model. The simulated grouting time was 30 min. The effective diffusion volume of the final grout and the overlap volume of the effective diffusion zone between the two grouting holes were extracted. The overlap rate of each set of tests was calculated according to formula (5), and the overlap effect was evaluated according to Table 3. The calculation results and overlap effect are shown in Table 4.

[0056] Table 3. Classification of Overlap Effect Levels Table 4. Grouting overlap rate and overlap effect in orthogonal test Data from 16 orthogonal experiments on the overlap rate show a significant difference between the diffusion and overlap effects of grout in a random three-dimensional fracture network. (Overlap rate (...)) As an evaluation index, the value ranges from 0.00% to 35.34%. Tests 9 (A3B1C3D4) and 10 (A3B2C4D3) achieved an "excellent" overlap effect, indicating that the combination of grouting pressure of 5 MPa–6 MPa, hole spacing of 9 m–10 m, grout viscosity of 0.6 Pa s–0.7 Pa s, and low hydrostatic pressure (0.5 MPa–1.0 MPa) is beneficial for forming a continuous curtain. Conversely, tests 1 (A1B1C1D1) and 3 (A1B3C3D3) had overlap rates of 0 or close to 0, and their overlap effects were all classified as "failures." Preliminary analysis suggests that the main reason for this may be that the grouting pressure was too low (3 MPa) or the hydrostatic pressure was too high (2 MPa), causing the grout to be unable to overcome the crack resistance and achieve effective diffusion.

[0057] The diffusion behavior of grout in a random three-dimensional fracture network exhibits significant spatial heterogeneity, particularly influenced by grouting pressure. To visually reveal the distribution pattern of effective grout diffusion volume under different grouting pressures, this paper divides 16 experimental groups into four categories based on pressure levels (3 MPa, 4 MPa, 5 MPa, 6 MPa). Based on the extracted effective diffusion volume data of the grout within 30 minutes, scatter plots are generated, as shown below. Figures 5-8 .

[0058] In the 3 MPa grouting pressure test group, as Figure 5 At 30 min, the effective diffusion volume distribution of the slurry was 87.95 m³. 3 ~266.52 m 3 The overlap rates were generally small, and the overlap rates in tests 1 and 3 were 0 or close to 0, corresponding to "failure" in overlap performance. This indicates that at low grouting pressures, the grout diffusion path is limited, making it difficult to form a good overlap area. In the grouting pressure test groups of 4 MPa and 5 MPa, as... Figure 6 and Figure 7 At 30 min, the effective diffusion volume distribution of the slurry was 230.63 m³. 3 ~340.37 m 3 The overlap rates are generally large. It is worth noting that in the levels controlled by factor B (hole spacing), the overlap rates controlled by levels 1 (9 m) and 2 (10 m) are relatively high, while those controlled by levels 3 (11 m) and 4 (12 m) are relatively low, even close to 0. For example, at a grouting pressure of 5 MPa, the overlap effect of hole spacings of 9 m and 10 m is "very good," while the overlap effect of hole spacings of 11 m and 12 m is "very poor" or "failed." This phenomenon stems from the heterogeneity of the fracture network; the choice of borehole location directly affects whether the grout can preferentially fill key fractures. Improper location will limit the effective diffusion range of the grout, thus reducing the effective diffusion volume. This indicates that hole spacing is also a key factor affecting the final overlap effect. In the 6 MPa grouting pressure test group, as... Figure 8 At 30 min, the effective diffusion volume distribution of the slurry was 311.24 m³. 3 ~352.78 m 3 The overall overlap is relatively large, indicating a favorable grouting effect. This suggests that at higher grouting pressures, the grout is more effective at overcoming the shear resistance of the crack walls, thus expanding the effective diffusion range of the grout.

[0059] The four figures reveal the significant controlling effect of grouting pressure on grout diffusion behavior. The overall trend shows a positive correlation between grouting pressure and diffusion volume, while also being influenced by the coupling effect of hole spacing, grout viscosity, and hydrostatic pressure. This phenomenon indicates that a higher grouting pressure environment enhances the grout's ability to overcome shear resistance at the fracture wall, promoting grout penetration into micro-fractures and thus expanding the effective diffusion range.

[0060] Step 3: Orthogonal experiments, as an efficient multi-factor experimental optimization method, can explore the main effects and interactions of various factors by constructing orthogonal experimental tables with balanced dispersion characteristics, while significantly reducing the number of experiments. This paper uses range analysis and variance analysis to analyze the simulation experiment results. Range analysis directly reflects the influence of factor level changes on slurry overlap rate by calculating the range of the index at different levels of each factor, and can quickly identify the key factors that play a dominant role in the index and the optimal combination of levels of each factor. Variance analysis constructs a variance decomposition model to decompose the total variation of experimental data into factor variation, interaction variation, and random error variation, and uses the F test to quantitatively determine the significance level of the influence of each factor and interaction on slurry overlap rate. Compared with range analysis, variance analysis can effectively distinguish the true influence of factors from the interference of random errors. It can not only accurately quantify the influence weight of each factor, but also ensure the statistical reliability of the analysis results through homogeneity of variance test and significance test. Tables 5 and 6 are the range analysis table and variance analysis table for overlap rate, respectively.

[0061] Table 5. Analysis of the worst results in grout overlap. Table 6. Analysis of Variance of Grout Overlap Effect Table 3 shows the order of influence of each factor on the overlap rate, indicating that among the factors considered in the experiment, the influence on the grouting overlap effect, from largest to smallest, is grouting pressure, hole spacing, hydrostatic pressure, and grout viscosity. Table 4 shows that under a confidence level of 99% (α=0.01), grouting pressure, hole spacing, and hydrostatic pressure all exhibit high significance, and the F-values ​​show that their significance ranking is consistent with the ranking of factors affecting the overlap effect shown in Table 3. The F-value for the influence of grout viscosity on the overlap rate is 3.78, which is less than the critical value of 9.28 corresponding to the significance level α=0.5, indicating that within the parameter range set in this experiment, the influence of grout viscosity on the grouting overlap effect is not statistically significant. Combining the analysis results of Tables 3 and 4, to more intuitively show the trend and variation law of the influence of different levels of each factor on the grout overlap rate, a trend chart of the average overlap rate at each factor level is drawn based on the average k-value of the overlap rate corresponding to each factor level, as shown below. Figure 9 As shown.

[0062] Grouting pressure The range of grouting pressure was 19.61%, making it the primary factor affecting the overlap rate. The trend chart of the average overlap rate across various factors shows that the overlap rate gradually increases with increasing grouting pressure. Essentially, grouting pressure directly determines the grout's ability to overcome shear resistance at the fracture wall, pore pressure in the rock mass, and hydrostatic pressure: when the pressure increases from 3 MPa to 6 MPa, the shear stress of the Bingham fluid significantly exceeds the yield stress, and the grout's penetration rate and diffusion radius in the fracture network increase simultaneously. High pressure promotes grout filling of micro-fractures, reducing the "blank areas" between pores.

[0063] Hole spacing The range of hole spacing was 17.59%, second only to grouting pressure. The trend chart of the average overlap rate for each factor shows that when the hole spacing is ≤10 m, the overlap rate remains above 20%. When the hole spacing increases to 11 m or more, the randomness of the fracture network leads to a sharp decrease in the probability of grout diffusion overlap, forming a through-flow leakage channel. It should be noted that the overlap rate difference between B1 (9 m) and B2 (10 m) is only 0.16%, but the drilling workload increases by 10% with a 9 m spacing. Therefore, a 10 m hole spacing can be prioritized in the project to achieve a balance between effectiveness and cost.

[0064] Slurry viscosity The range of slurry viscosity was 5.03%, having the least significant impact on the overlap rate. The trend graph of the average overlap rate at various factor levels shows that the overlap rate gradually increases as the slurry viscosity decreases, but the increase in its mean value k is slow. There are roughly two reasons for this: firstly, the viscosity variation range in the experiment was relatively narrow (0.6 Pa s ~ 0.9 Pa s), and all ranges conformed to Bingham fluid characteristics, with small differences in yield stress; secondly, the randomness of the fracture network dominated the slurry diffusion path, masking the influence of viscosity and thus reducing the rate of change of the average overlap rate.

[0065] hydrostatic pressure The range of hydrostatic pressure was 14.84%, ranking third among the factors considered in the experiment. The trend chart of the average overlap rate for each factor level shows that the overlap rate gradually increases as the hydrostatic pressure decreases. This is because the grouting pressure difference (grouting pressure - hydrostatic pressure) directly affects the grout seepage dynamics. The grout seepage velocity is positively correlated with the grouting pressure difference and negatively correlated with grout viscosity and fracture resistance. When the hydrostatic pressure decreased from 2.0 MPa to 0.5 MPa, the maximum grouting pressure difference increased from 1.0 MPa to 5.5 MPa, significantly enhancing the grout's ability to overcome groundwater seepage resistance and expanding the effective diffusion volume.

[0066] Based on the results of range analysis and variance analysis, the primary and secondary influences and significance of grouting pressure, hole spacing, hydrostatic pressure, and grout viscosity on the overlap rate were clarified: grouting pressure (range 19.61%) was the dominant factor, followed by hole spacing (range 17.59%) and hydrostatic pressure (range 14.84%), while grout viscosity (range 5.03%) had no significant effect. The overlap rate was calculated based on Table 4. The theoretically optimal combination of levels was obtained as A3B1C3D4 (grouting pressure 5 MPa, hole spacing 9 m, grout viscosity 0.7 Pas, hydrostatic pressure 0.5 MPa).

[0067] Step 4: Although single-factor analysis revealed the independent effects of each parameter, in actual curtain grouting projects, multiple factors often exhibit coupling interactions, which may significantly alter the grout diffusion path and overlap effect. To analyze this coupling mechanism and overcome the limitations of single-factor analysis, cubic spline interpolation was used to grid the scatter data in this orthogonal experiment, such as... Figures 10-15 It is a diagram showing the overlapping effect under the interaction of two factors.

[0068] The synergistic influence of the interaction between grouting pressure and hole spacing on the lap joint effect, such as... Figure 10 As shown, when the hole spacing is constant, the overlap rate increases with increasing grouting pressure. This indicates that a higher grouting pressure environment can effectively compensate for the reduction in effective grout diffusion volume caused by the increased spacing. This phenomenon is attributed to the grout's stronger shear stress resistance under higher pressure grouting, which promotes lateral penetration of the grout into the fracture network. However, when the grouting pressure is constant, the overlap rate between 10 m and 11 m hole spacing decreases rapidly with increasing hole spacing. This indicates that as the spacing of the grouting holes increases, the drilling position may avoid key fractures, which directly affects whether the grout can effectively fill key water-conducting fractures, thus affecting the final overlap rate.

[0069] Figure 11The interaction between grouting pressure and grout viscosity on the grouting overlap effect is illustrated in the figure. As can be seen from the figure, the grouting overlap rate is generally higher within the range of grouting pressure (5 MPa–6 MPa) and grout viscosity (0.6 Pa s–0.75 Pa s). The grouting overlap rate generally increases with increasing grouting pressure. At a grouting pressure of 4.5 MPa, the grouting overlap rate initially increases and then gradually decreases with increasing grout viscosity, with no significant change. Within the grouting pressure range of 4.5 MPa–6 MPa, the overlap rate generally decreases with increasing grout viscosity, while the change is reversed when the grouting pressure range of 3 MPa–4.5 MPa. This indicates that the change in grout viscosity has no significant effect on the grouting overlap effect in this experiment, which also verifies the conclusion from the analysis of variance table of grouting overlap effect that "the effect of grout viscosity on the grouting overlap effect is not statistically significant."

[0070] Figure 12 The interaction between grouting pressure and hydrostatic pressure on the lap joint effect is illustrated in the figure. It can be seen that when the hydrostatic pressure is constant, the lap joint rate increases significantly with increasing grouting pressure; conversely, when the grouting pressure is constant, the lap joint rate decreases with increasing hydrostatic pressure. This trend stems from the dominant role of the grouting pressure differential in the grout diffusion dynamics. A higher grouting pressure differential enhances the grout's ability to overcome fracture resistance and groundwater seepage force, promoting lateral penetration and overlap of the grout within the fracture network, thereby increasing the grouting lap joint rate.

[0071] Figure 13 This study demonstrates the synergistic effect of grout viscosity and hole spacing on the overlap effect. The figure shows that regions with higher overlap rates are mostly distributed in areas with smaller hole spacing (9 m–10 m) and lower grout viscosity (0.6 Pa s–0.75 Pa s). When the hole spacing is 10 m, the overlap rate increases slowly as the grout viscosity decreases; however, when the hole spacing increases to 12 m, the influence of viscosity change on the overlap rate weakens significantly, and the overlap rate remains low, even approaching 0. This phenomenon can be explained by the rheological properties of the grout and the geometric characteristics of the fracture network: low-viscosity grout has good fluidity, and when the grout hole spacing is small, it easily diffuses fully in the fracture and achieves overlap; while when the grout hole spacing is large, the grout filling path increases, and the grout tends to viscously dissipate energy during diffusion, weakening the overlap effect.

[0072] The synergistic effect of the interaction between hydrostatic pressure and hole spacing on the overlapping effect, such as... Figure 14As shown in the figure, when the hydrostatic pressure is constant, the grout overlap rate gradually increases as the hole spacing decreases. This indicates that under low hydrostatic pressure, the grout easily forms an effective overlap in small-spacing fractures; however, high hydrostatic pressure exacerbates the grout diffusion resistance, especially in large-spacing fractures, where the grout diffusion path is prolonged and easily diluted by water, leading to a reduction in the effective diffusion area and a decrease in the overlap rate.

[0073] Figure 15 The interaction between hydrostatic pressure and slurry viscosity on the lap joint effect is illustrated in the figure. The peak lap joint rate occurs in the combination region of low hydrostatic pressure (0.5 MPa) and low viscosity (0.7 Pa s). As the hydrostatic pressure gradually increases, the lap joint rate gradually decreases. This indicates that under lower hydrostatic pressure, low-viscosity slurry easily diffuses and fills micro-cracks, improving the lap joint rate; while under higher hydrostatic pressure, the effect of slurry viscosity is masked. For example, at a hydrostatic pressure of 2 MPa, the slurry viscosity exhibits irregular changes, and the overall lap joint rate is relatively small.

[0074] Conclusion: This study addresses the difficulty in predicting the effective diffusion range of grout in curtain grouting in deep mines. A stochastic three-dimensional fracture network model was constructed, and an L16(4) fracture network was designed. 5 An orthogonal experiment was conducted to systematically investigate the influence of grouting parameters on the grout overlap effect. The main conclusions are as follows: (1) The effective diffusion area of ​​grout in 16 sets of simulated tests was extracted, and the grouting overlap rate was defined as an index to evaluate the curtain overlap effect. This method can intuitively evaluate the degree of overlap of grout in adjacent grouting holes. Compared with traditional indirect evaluation indexes, it can better reflect the actual diffusion and sealing state of grout in the fracture network.

[0075] (2) The experimental results show that the influence of each factor on the grout overlap rate is significantly different, and the order of influence is grouting pressure > hole spacing > hydrostatic pressure > grout viscosity. Among them, grouting pressure, hole spacing and hydrostatic pressure have a highly significant influence on the overlap rate (α=0.01), while grout viscosity has no significant influence in the experimental range of 0.6 Pa s to 0.9 Pa s.

[0076] (3) The theoretical optimal parameter combination for curtain grouting under random three-dimensional fracture network in the study area was determined by analysis to be A4B2C4D4, namely, grouting pressure 6 MPa, hole spacing 10 m, grout viscosity 0.6 Pa s, and hydrostatic pressure 0.5 MPa. This combination can maximize the effective diffusion range and overlap rate of grout, forming a continuous and complete anti-seepage curtain.

[0077] The foregoing description, with reference to preferred embodiments, details an exemplary implementation of the mine curtain grouting slurry diffusion method and system proposed by the present invention. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of the present invention, and various combinations can be made to the various technical features and structures proposed by the present invention without exceeding the protection scope of the present invention, which is determined by the appended claims.

Claims

1. A method of mine curtain grout dispersion, characterized by, Includes the following steps: S10: Model Construction: A stochastic three-dimensional fracture network model is constructed using multiphysics numerical simulation software. By solving a set of partial differential equations under multi-field coupling, the mechanical and permeability characteristics of fractured rock mass, the seepage and diffusion behavior of grouting fluid, and the solidification reaction of grouting fluid are simulated. S20: Orthogonal test: Multiple grouting holes are opened on the three-dimensional fracture network model, and grouting is carried out one by one or in groups to achieve crack sealing and curtain overlap; among them, an orthogonal test scheme is adopted, and four influencing factors are selected: grouting pressure, hole spacing, grout viscosity and hydrostatic pressure, and multiple levels are set for each influencing factor; S30: Evaluation index: The overlap rate of adjacent grouting holes is used as the evaluation index of the grouting sealing effect to evaluate the grouting overlap effect of the three-dimensional fracture network model after orthogonal experiment. S40: Results Analysis: Based on the grouting evaluation and grading of the simulation test, an orthogonal experimental table with dispersion characteristics was constructed, and the results of the simulation test were analyzed by range analysis and variance analysis.

2. The method for diffusion of grout in mine curtain grouting according to claim 1, characterized in that, In step S10, constructing the random three-dimensional fracture network model specifically includes: By statistically analyzing the center point coordinates, attitude, and size measured in the field, the probability distribution function was determined. Then, Monte Carlo random sampling was used to generate a large number of virtual fractures that followed a specific distribution, which were finally combined into a three-dimensional DFN model; among which, (1) Uniform random model of crack location: The distribution of the fracture center points in all-directional space follows a uniform distribution, and its probability density function is: In the formula, , are the maximum and minimum values of the range of the position parameter in this dimension, respectively. (2) Power-law stochastic model of crack size: In the formula, a is the power-law distribution index, reflecting the power-law attenuation characteristics of the size distribution, is the minimum measured value of the fracture length; (3) Fisher stochastic model of fracture orientation: In the formula, θ is the angular deviation of the average angle of the ellipse direction described by the probability density function of the Fisher distribution, and K is called the Fisher diffusion coefficient or Fisher constant.

3. The method for diffusion of grout in mine curtain grouting according to claim 1, characterized in that, In step S20, during the fissure rock mass grouting process, a variety of cement-water glass double liquid slurries with different viscosities are selected as the to-be-grouted liquid, and the plurality of slurries with different viscosities all conform to the Bingham fluid characteristics; the rheological characteristics are that there is a yield stress When the shear stress is lower than , the slurry does not flow; when the shear stress is higher than , the shear stress of the slurry is proportional to the shear rate; wherein, the rheological equation is: wherein is the shear stress, is the yield stress, is the plastic viscosity, is the shear rate.

4. The method for diffusion of grout in mine curtain grouting according to claim 1, characterized in that, In step S20, the diffusion region formed by the grout diffusion includes the effective diffusion region. In the three-dimensional fracture network grouting numerical simulation of multiphysics numerical simulation software, the effective diffusion region is the region with a grout integral number ≥ 0.

5.

5. The method for diffusion of grout in mine curtain grouting according to claim 1, characterized in that, In step S30, the lap rate The calculation formula is: wherein Veff is the average value of the overlapping volume of the effective diffusion region between the two pores, Veff is the average value of the effective diffusion volume of the single pore.

6. The method for diffusion of grout in mine curtain grouting according to claim 1, characterized in that, In step S30, the evaluation of the grouting overlap effect includes: when the grout diffusion zone between two grouting holes fully overlaps or overlaps, the overlap rate is high, the curtain continuity is good, and it is conducive to forming a reliable anti-seepage system; conversely, if the grout diffusion range is insufficient, there are unfilled gaps or weak areas between the holes, the overlap rate is low, resulting in curtain discontinuity and causing problems such as leakage, water inrush or decreased surrounding rock stability.

7. The method for diffusion of grout in mine curtain grouting according to claim 1, characterized in that, In step S40, the simulation test results are analyzed using range analysis and variance analysis, specifically including single-factor analysis and interaction factor analysis of grouting pressure, hole spacing, grout viscosity, and hydrostatic pressure. The interaction factor analysis includes the following: When the hole spacing is constant, the overlap rate increases with the increase of grouting pressure. As the spacing of grouting holes increases, the drilling position may avoid key fractures, which directly affects whether the grout can effectively fill the key water-conducting fractures, thus affecting the final overlap rate. The change in grout viscosity has no significant effect on the grouting overlap effect; When the hydrostatic pressure is constant, the overlap rate increases significantly with the increase of grouting pressure; conversely, when the grouting pressure is constant, the overlap rate decreases with the increase of hydrostatic pressure. Low-viscosity grout has good fluidity. When the spacing between grouting holes is small, it is easy to spread fully in the crack and achieve overlap. However, when the spacing between grouting holes is large, the grout filling path increases, and the grout is prone to viscosity and energy consumption during diffusion, which weakens the overlapping effect. When the hydrostatic pressure is constant, the grouting overlap rate gradually increases as the hole spacing decreases; when the hole spacing is constant, the grouting overlap rate gradually increases as the hydrostatic pressure decreases. Under low hydrostatic pressure, low-viscosity slurry easily diffuses and fills tiny cracks, improving the overlap rate; while under high hydrostatic pressure, the effect of slurry viscosity is masked.

8. A grout diffusion system for mine curtain grouting, characterized in that, include: The model building module is configured to build a stochastic three-dimensional fracture network model using multiphysics numerical simulation software. By solving a set of partial differential equations under multi-field coupling, it simulates the mechanical and permeability characteristics of fractured rock mass, the seepage and diffusion behavior of grouting fluid, and the solidification reaction of grouting fluid. The orthogonal test module is configured to open multiple grouting holes on a three-dimensional fracture network model, and perform grouting one by one or in groups to achieve crack sealing and curtain overlap. The orthogonal test scheme is adopted, and four influencing factors are selected: grouting pressure, hole spacing, grout viscosity and hydrostatic pressure, and multiple levels are set for each influencing factor. The evaluation index module is configured to use the overlap rate of adjacent grouting holes as an evaluation index of the grouting sealing effect to evaluate the grouting overlap effect of the three-dimensional fracture network model after orthogonal experiment. The results analysis module is configured to construct an orthogonal experimental table with dispersion characteristics for grouting evaluation and grading based on simulation tests, and to analyze the simulation test results using range analysis and variance analysis.

9. The mine curtain grouting slurry diffusion system according to claim 8, characterized in that, During the grouting process in fractured rock masses, various cement-water glass two-component grouts with different viscosities were selected as the grouting fluids. All of these different grouts conformed to Bingham fluid characteristics; their rheological properties included the presence of yield stress. When the shear stress is lower than When the shear stress is higher than 1, the slurry does not flow; when the shear stress is higher than 1, the slurry does not flow. At that time, the shear stress of the slurry is directly proportional to the shear rate; its rheological equation is: In the formula, For shear stress, For yield stress, For plastic viscosity, denoted as shear rate.

10. The mine curtain grouting slurry diffusion system according to claim 8, characterized in that, Overlap rate The calculation formula is: In the formula, This represents the average value of the overlapping volume of the effective diffusion zone of the slurry between the two holes. This represents the average effective diffusion volume of a single pore.

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