Overlying strata multilevel grouting design optimization method based on computer simulation

Abstract

The invention relates to the technical field of computer simulation, and discloses a computer simulation-based overlying strata multilevel grouting design optimization method, which comprises the following steps of: constructing a three-dimensional geomechanical model of a goaf according to geological exploration data; calculating development characteristics of each layer in the overlying strata of the goaf, and constructing a grouting bearing layer position of the goaf according to the development characteristics; fracture development characteristics and horizon stress distribution are analyzed; according to fracture development characteristics and horizon stress distribution, analyzing grouting simulation parameters of the horizon of the grouting bearing layer; generating a multi-level layered grouting simulation scheme of the position of the grouting bearing layer; generating a digital track of the position of a grouting bearing layer according to the multi-level layered grouting simulation scheme, and generating a grouting control simulation instruction according to the digital track; and according to the grouting control simulation instruction, multi-level grouting simulation operation is carried out on the position of the grouting bearing layer, and a multi-level grouting simulation result is output. According to the method, the accuracy of the grouting level of overlying strata multi-level design optimization can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of computer simulation, and in particular to a method for optimizing overburden multi-level grouting design based on computer simulation. Background Art

[0002] Goafs created during underground coal mining damage the overlying rock strata, eventually impacting the surface. This causes ground movement and deformation, resulting in prolonged subsidence and making the damaged land difficult to reuse. By comprehensively analyzing the overlying rock damage in old goafs and recreating key bearing strata to support the overlying rock strata, the ground is no longer affected by residual surface deformation, freeing up land resources above the old goafs.

[0003] Currently, there are two main strategies for controlling surface subsidence. One involves mining technology, using methods such as retaining coal pillars, controlling mining height, and backfill mining to control the height of overburden failure and thereby control surface subsidence. The other involves grouting the overburden to fill the overburden separation zone, reducing the space for overburden migration and thus controlling surface subsidence. However, both of these methods have limitations. The first method wastes some coal resources or increases underground mining operations, resulting in limited economic benefits. The second method requires coordination with underground mining. The overburden movement cycle in the goaf is long, and if the bearing capacity of the grouting layer is poor, it will be difficult to provide long-term support for surface subsidence control, resulting in limited effectiveness in controlling residual surface deformation. Both of these methods are designed to control surface subsidence in the early stages of mining or in the initial mining area, and are generally ineffective in controlling surface subsidence in established goaf areas. Therefore, it is necessary to conduct multi-level grouting of the reconstructed key bearing strata based on the characteristics of the overburden strata in the goaf to control surface subsidence. Summary of the Invention

[0004] The present invention provides a method for optimizing multi-level grouting design of overburden rock based on computer simulation, the main purpose of which is to solve the problem of low grouting accuracy during optimization of multi-level grouting design of overburden rock.

[0005] To achieve the above-mentioned object, the present invention provides a method for optimizing multi-level grouting design in overburden based on computer simulation, comprising: Collecting geological exploration data of the goaf, digitally processing the geological exploration data, and constructing a three-dimensional geomechanical model of the goaf; Performing finite element numerical simulation on the three-dimensional geomechanical model, calculating the development characteristics of each layer in the overburden layer of the goaf, and constructing the grouting bearing layer layer of the goaf according to the development characteristics; Analyze the crack development characteristics and layer stress distribution of the grouting bearing layer; Analyzing the grouting simulation parameters of the grouting bearing layer according to the crack development characteristics and the layer stress distribution, and iteratively optimizing the grouting simulation parameters based on the rheological characteristics of the grouting material; Dynamically generate a multi-level layered grouting simulation scheme for the grouting bearing layer using the optimized grouting simulation parameters; Generating a digital trajectory of the grouting borehole in the grouting bearing layer according to the multi-level layered grouting simulation scheme, and generating a grouting control simulation instruction according to the digital trajectory; A multi-level grouting simulation operation is performed on the grouting bearing layer according to the grouting control simulation instruction, and a multi-level grouting simulation result is output.

[0006] Optionally, the digital processing of the geological exploration data to construct a three-dimensional geomechanical model of the goaf includes: Performing a drilling lithology identification operation on the geological exploration data to generate lithology distribution data of overlying rock layers in the goaf; The fracture zone boundary calibration operation is performed on the overlying rock layer of the goaf to obtain the coordinate range of the subsidence zone; Performing spatial interpolation calculation on the overburden strata based on the coordinate range of the subsidence zone to generate a density cloud map of the structural surface of the overburden strata; Constructing a block discrete network model with fault constraints on the goaf according to the density cloud map and the lithology distribution data; The block discrete network model is used as a three-dimensional geomechanical model of the goaf.

[0007] Optionally, performing finite element numerical simulation on the three-dimensional geomechanical model to calculate the development characteristics of each layer in the overburden layer of the goaf includes: Loading rock mass mechanical parameters corresponding to the three-dimensional geomechanical model based on the geological exploration data, and constructing an elastic-plastic constitutive model of the overburden layer above the goaf according to the rock mass mechanical parameters; Dividing the three-dimensional geomechanical model into grid units according to the elastic-plastic constitutive model of the overburden rock to obtain a grid unit group; Multi-condition numerical simulation is performed on the grid unit group to obtain development characteristic parameters of each layer in the overburden layer, and the development characteristics of each layer in the overburden layer are determined based on the development characteristic parameters.

[0008] Optionally, the step of constructing a grouting bearing layer in the goaf according to the development characteristics includes: Mapping the development characteristics into the three-dimensional geomechanical model and outputting a horizon feature matrix; Screening the layers in the layer feature matrix based on preset layer conditions to obtain candidate bearing layer areas; Determining the boundary range of the grouting bearing layer according to a preset water-conducting fracture zone height algorithm; The grouting bearing layer position is determined in the bearing layer candidate area according to the boundary range.

[0009] Optionally, the analyzing the crack development characteristics and layer stress distribution of the grouting bearing layer includes: Extracting crack density parameters, crack strike parameters and stress concentration factor parameters from the layer characteristic matrix according to the layer coordinates of the grouting bearing layer; generating a directed graph model of fracture connectivity based on the fracture density parameter and the fracture strike parameter; Determining the fracture development characteristics of the grouting bearing layer according to the path trend in the directed graph model of fracture connectivity; A layer stress gradient cloud map is generated based on the stress concentration factor parameters, and the layer stress distribution of the grouting bearing layer is determined according to the cloud map trend of the layer stress gradient cloud map.

[0010] Optionally, analyzing the grouting simulation parameters of the grouting bearing layer according to the fracture development characteristics and the layer stress distribution includes: Determining the number of horizontal layer groups of the grouting bearing layer according to the thickness of the grouting bearing layer and the grouting diffusion radius; Determine the grouting position corresponding to each layer in the horizontal layer group according to the crack development characteristics and the layer stress distribution; Calculating the fracture space volume of each layer in the horizontal stratification group according to the fracture connectivity in the fracture development characteristics; Calculating the grouting amount corresponding to the grouting position by the volume of the fracture space and the preset rock mass expansion coefficient, and determining the grouting pressure at the grouting position according to the layer stress distribution; The grouting amount, the grouting pressure and the grouting position are determined as grouting simulation parameters.

[0011] Optionally, the iterative optimization of the grouting simulation parameters based on the rheological characteristics of the grouting material includes: Extracting a dynamic viscosity function from the rheological characteristics according to the crack development characteristics of the grouting bearing layer; generating a slurry diffusion control equation based on the dynamic viscosity function and the layer stress distribution; performing a finite difference solution operation on the slurry diffusion control equation and outputting a grouting coverage radius; Calculating a pressure compensation gradient based on a deviation between the grouting coverage radius and a preset target coverage area; The grouting pressure parameters are iteratively updated based on the pressure compensation gradient, and when the coverage radius deviation of a preset number of iterations is less than or equal to a preset deviation threshold, the optimized grouting simulation parameters are output.

[0012] Optionally, the dynamically generating a multi-level layered grouting simulation scheme for the grouting bearing layer using the optimized grouting simulation parameters includes: Dividing the grouting bearing layer into annular areas with increasing radial distances, and determining the grouting execution order according to the annular areas; Determining the order of executing grouting up and down according to the order of the layers of the grouting bearing layer; Generate a grouting sequence according to the grouting execution order of distance and the grouting execution order of top and bottom; Performing a fissure plugging simulation operation on the grouting area below the grouting bearing layer to construct a virtual boundary of the grouting isolation layer; A grouting layer simulation unit is constructed according to the virtual boundary of the grouting layer. When the strength of the grouting layer simulation unit meets the preset strength condition, a multi-level layered grouting simulation scheme is generated according to the grouting sequence and the optimized grouting simulation parameters.

[0013] Optionally, generating a digital trajectory of the grouting borehole in the grouting bearing layer according to the multi-level layered grouting simulation scheme includes: Generating a preliminary drilling axis of the grouting bearing layer according to the grouting position in the multi-level layered grouting simulation scheme; Analyzing the drillability of the rock formation in the preliminary drilling axis to obtain a target risk marker segment; performing a trajectory error compensation operation on the preliminary drilling axis according to the target risk marker segment and preset gyro inclinometer data to obtain a drilling control point set; A digital trajectory of the grouting bearing layer is generated according to the drilling control point set.

[0014] Optionally, performing a multi-level grouting simulation operation on the grouting bearing layer according to the grouting control simulation instruction and outputting a multi-level grouting simulation result includes: monitoring the orifice pressure and cumulative grouting volume of the grouting bearing layer in real time according to the grouting control simulation instruction; If the instantaneous rising rate of the orifice pressure exceeds a preset rising threshold and the accumulated grouting volume reaches a preset first grouting threshold, triggering a stop grouting simulation instruction in the grouting control simulation instruction; If the orifice pressure shows a downward trend within a preset time range or the accumulated grouting volume exceeds a preset second grouting threshold, triggering the emergency positioning simulation instruction in the grouting control simulation instruction; Scan the overburden weak surface of the grouting bearing layer according to the emergency positioning simulation instruction to obtain a slurry leakage positioning point, and execute the plugging material injection simulation instruction according to the slurry leakage positioning point; monitoring whether the orifice pressure shows a stable trend after the plugging material injection simulation instruction is executed, and triggering a resume grouting simulation instruction in the grouting control simulation instruction when the orifice pressure shows a stable trend; A grouting visualization diagram is generated according to the stop grouting simulation instruction, the emergency positioning simulation instruction and the resume grouting simulation instruction, and a multi-level grouting simulation result is determined through the grouting visualization diagram.

[0015] The embodiment of the present invention quantitatively analyzes and dynamically optimizes the entire process from geological data acquisition to grouting simulation, achieving precise and controllable construction of multi-level grouting in overburden to reconstruct the key bearing layer in the goaf area. The new bearing layer formed can effectively support the overburden layer, significantly control the residual deformation of the surface, and liberate the land resources above the old goaf. At the same time, this process solves technical problems such as the deviation caused by relying on experience to select the grouting layer in the traditional method, insufficient grouting or slurry leakage caused by unreasonable design of grouting simulation parameters, and poor control effect on surface subsidence in old goaf. Through technical means such as three-dimensional modeling, finite element simulation, and rheological property optimization, the scientific nature of the grouting scheme and the stability of the bearing layer are ensured, and the efficiency and reliability of mining damage control are improved. Therefore, the multi-level grouting design optimization method for overburden based on computer simulation proposed by the present invention can solve the problem of low grouting accuracy when optimizing the multi-level grouting design for overburden. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic flow chart of a method for optimizing overburden multi-level grouting design based on computer simulation provided in one embodiment of the present invention.

[0017] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0018] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] The embodiment of the present application provides a method for optimizing the design of multi-level grouting of overburden based on computer simulation. The execution subject of the method for optimizing the design of multi-level grouting of overburden based on computer simulation includes but is not limited to at least one of the electronic devices such as a server and a terminal that can be configured to execute the method provided by the embodiment of the present application. In other words, the method for optimizing the design of multi-level grouting of overburden based on computer simulation can be executed by software or hardware installed on a terminal device or a server device, and the software can be a blockchain platform. The server includes but is not limited to: a single server, a server cluster, a cloud server or a cloud server cluster, etc. The server can be an independent server, or it can be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (CDNs), and big data and artificial intelligence platforms.

[0020] Reference Figure 1 FIG. 1 is a flow chart of a method for optimizing multi-level grouting design in overburden based on computer simulation according to an embodiment of the present invention. In this embodiment, the method for optimizing multi-level grouting design in overburden based on computer simulation includes: S1. Collect geological exploration data of the goaf, digitally process the geological exploration data, and construct a three-dimensional geomechanical model of the goaf.

[0021] In the embodiment of the present invention, the geological exploration data refers to a collection of geological information such as rock layer distribution, lithologic characteristics, and fracture development status in the goaf area obtained through field measurement methods such as drilling and geophysical exploration.

[0022] In detail, geological exploration data of the goaf can be collected from a pre-stored storage area through computer statements with data capture functions (such as Java statements, Python statements, etc.), where the storage area includes but is not limited to a database and a blockchain.

[0023] Furthermore, in order to provide an accurate geological basis for subsequent overburden analysis and grouting scheme design, it is necessary to quantify and visualize the overburden characteristics of the goaf to ensure that subsequent finite element numerical simulation, grouting layer determination and other steps have reliable data support.

[0024] In an embodiment of the present invention, the three-dimensional geomechanical model refers to a three-dimensional digital model constructed based on geological exploration data of the goaf (such as core characteristics obtained by drilling, rock layer distribution information obtained by geophysical exploration, etc.). For example, in the old goaf scene of a coal mine, the model can clearly present the alternating distribution of sandstone and mudstone, as well as the spatial position of fracture zones and curved subsidence zones, providing a visual three-dimensional carrier for subsequent analysis of the stress state of the overburden.

[0025] In an embodiment of the present invention, the digital processing of the geological exploration data to construct a three-dimensional geomechanical model of the goaf includes: Performing a drilling lithology identification operation on the geological exploration data to generate lithology distribution data of overlying rock layers in the goaf; The fracture zone boundary calibration operation is performed on the overlying rock layer of the goaf to obtain the coordinate range of the subsidence zone; Performing spatial interpolation calculation on the overburden strata based on the coordinate range of the subsidence zone to generate a density cloud map of the structural surface of the overburden strata; Constructing a block discrete network model with fault constraints on the goaf according to the density cloud map and the lithology distribution data; The block discrete network model is used as a three-dimensional geomechanical model of the goaf.

[0026] Specifically, laboratory analysis of drill core samples from geological exploration data is performed. X-ray diffraction is used to determine the mineral composition of the rock formations. Combined with acoustic logging data, the rock hardness is determined to generate lithologic distribution data for the overburden layers in the goaf. The lithologic identification results for each drill hole are then linked to the drill hole coordinates. Planar interpolation methods (such as the inverse distance weighted method) are then used to create planar and cross-sectional lithologic distribution maps of the overburden layers in the goaf, clarifying the spatial distribution ranges of different lithologies (such as sandstone, mudstone, and limestone). For example, lithologic identification of 20 drill holes in a coal mine goaf revealed that sandstone predominates within the 100-150m depth range, accounting for 70% of the layer area, while mudstone predominates within the 150-200m depth range, comprising 65%.

[0027] Specifically, the fracture zone refers to the rock layer area above the goaf where a large number of fractures have been generated due to mining but no collapse has occurred. The subsidence zone refers to the rock layer area above the fracture zone that has bent and sunk. The boundaries between the two need to be calibrated by combining actual measurement and theoretical calculation. The fracture zone boundary calibration operation specifically includes: First, geophysical methods (such as seismic wave reflection method and sound wave transmission method) are used to obtain the physical properties of the overburden layer (such as wave velocity and resistivity). Because the wave velocity in the fracture development area will decrease (such as the wave velocity of the intact rock layer is 4000m / s, the wave velocity of the fracture zone is reduced to 2500m / s), the wave velocity mutation interface is identified based on this, and the upper boundary of the fracture zone is preliminarily determined; secondly, combining the "three zones" Theoretical height calculation formulas (such as the empirical formula for calculating the height of the fracture zone based on mining height and lithology) are used to correct the geophysical results. For example, if the mining height of a certain goaf is 5m, the calculated height of the fracture zone is 30m. Combined with the depth of the geophysical wave velocity mutation interface, the upper boundary of the fracture zone is finally determined. The coordinate range of the subsidence zone refers to the position limit of the subsidence zone in three-dimensional space. The surface settlement points are measured by total station or GPS to invert the rock stratum settlement range and determine the upper and lower boundary coordinates of the subsidence zone.

[0028] Furthermore, the Kriging interpolation algorithm was used to process the overburden strata data within the coordinate range of the subsidence zone to generate a density cloud map of the overburden strata's structural surfaces. This cloud map uses a color gradient to represent the density of structural surfaces, with red areas representing densely populated areas. Based on the distribution of structural surfaces and lithologic data in the density cloud map, finite element software was used to delineate fault-constrained block units. The block discrete network model divides the overburden strata into several independent blocks, creating a three-dimensional model of the rock structure through the contact relationships between the blocks. The construction process is as follows: First, the spatial distribution of structural surfaces is determined based on the density cloud map (for example, the red high-density area corresponds to the dense structural surface), and the structural surface is used as the segmentation boundary of the block; second, combined with the lithologic distribution data, the blocks in the same lithologic area have the same mechanical parameters (for example, the elastic modulus of sandstone blocks is 25GPa, and that of mudstone blocks is 8GPa); finally, the fault constraint condition is introduced, that is, the blocks on both sides of the fault do not penetrate, and the relative displacement between the blocks must conform to the mechanical properties of the fault (for example, the shear displacement coefficient along the fault strike is 0.2). The block discrete network model integrates the lithologic distribution (mechanical parameter basis), structural surface density (rock integrity characteristics) and fault constraints (boundary conditions), and completely covers the core information required for geomechanical analysis, and can be directly used as a three-dimensional geomechanical model.

[0029] Furthermore, through multi-source data integration and numerical modeling, the quantification and visualization of the geological characteristics of the goaf were achieved, providing geometric boundaries and mechanical parameter carriers for finite element numerical simulation.

[0030] S2. Perform finite element numerical simulation on the three-dimensional geomechanical model, calculate the development characteristics of each layer of the overburden layer in the goaf, and construct the grouting bearing layer layer of the goaf according to the development characteristics.

[0031] In the embodiment of the present invention, finite element numerical simulation refers to a numerical calculation method that discretizes a three-dimensional geomechanical model into a finite number of units and simulates the stress state of the overburden layer by solving the mechanical equilibrium equation; development characteristics refer to a set of parameters such as the crack density, deformation, and stress concentration degree of the overburden layer that reflect the stability of the rock formation.

[0032] In the embodiment of the present invention, the finite element numerical simulation of the three-dimensional geomechanical model is performed to calculate the development characteristics of each layer in the overburden layer of the goaf, including: Loading rock mass mechanical parameters corresponding to the three-dimensional geomechanical model based on the geological exploration data, and constructing an elastic-plastic constitutive model of the overburden layer above the goaf according to the rock mass mechanical parameters; Dividing the three-dimensional geomechanical model into grid units according to the elastic-plastic constitutive model of the overburden rock to obtain a grid unit group; Multi-condition numerical simulation is performed on the grid unit group to obtain development characteristic parameters of each layer in the overburden layer, and the development characteristics of each layer in the overburden layer are determined based on the development characteristic parameters.

[0033] In detail, the rock mechanical parameters such as elastic modulus (e.g. 25GPa for sandstone and 8GPa for mudstone), Poisson's ratio (0.2-0.3), internal friction angle (30°-40°) are extracted from geological exploration data and substituted into the Drucker-Prager elastic-plastic constitutive equation to construct an elastic-plastic constitutive model of overburden, so that the model can truly reflect the elastic deformation and plastic yield characteristics of rock layers of different lithologies under stress; according to the geometric characteristics of the rock layers reflected by the elastic-plastic constitutive model of overburden (e.g. the total thickness of the overburden is 100m, divided into fracture zones, curved subsidence zones and other layers, each with a thickness of 20-30m), the basic scale of grid division is determined: in areas with dense fracture development (such as the red high-density area identified by the density cloud map), a fine grid is used, and the unit size is set to 1m×1m×1m to accurately capture the stress changes near the fracture; in areas with uniform lithology and A coarse grid is used in structurally intact areas (such as the blue low-density area) with a cell size of 5m×5m×5m to reduce the amount of calculation. Alternatively, based on the geometric characteristics of the elastic-plastic constitutive model of the overburden, the three-dimensional geomechanical model is divided using tetrahedral elements. The grid size is set to 0.5m×0.5m in the area with dense fractures and 2m×2m in the area with intact rock formations, forming a grid cell group containing 500,000 cells. The grid cell group discretizes the three-dimensional geomechanical model into a collection of several continuous and non-overlapping small cells, each of which contains corresponding lithologic information and mechanical parameters.

[0034] Specifically, multi-condition numerical simulation refers to setting different mining conditions (such as mining depth, goaf range, mining intensity, etc.), and calculating the mechanical response of the grid unit group through finite element software to fully reflect the change law of the overburden strata under different scenarios, that is, setting multiple groups of simulation conditions: combined with the actual coal mining, three groups of conditions are set, namely, mining depth of 300m, goaf range of 100m×50m; mining depth of 400m, goaf range of 150m×80m; mining depth of 500m, goaf range of 200m×100m. Each group of conditions simulates the overburden change process 100 days after mining, and then solves the grid unit group through finite element software: based on the elastic-plastic constitutive model of the overburden, self-weight stress (calculated according to the rock density of 2500kg / m³) and goaf boundary conditions (stress within the goaf range is released to 0), solve the stress, strain and displacement values ​​of each unit, and output the development characteristic parameters of each unit. For example, at a mining depth of 300m, a unit is calculated to have a fracture density of 1.2 fractures / m², a settlement of 0.5m, a stress concentration factor of 1.3, and a plastic strain of 0.002. The average of all unit parameters in the same layer (e.g., a fracture zone) is used to obtain the development characteristic parameters of that layer (e.g., an average fracture density of 1.5 fractures / m² and an average settlement of 0.8m in the fracture zone). Development characteristic parameters are quantitative indicators that characterize the state of the overburden layer, including fracture density, settlement, stress concentration factor, and plastic strain. The development characteristics are then determined based on these parameters: if the average fracture density of a layer is greater than 1 fracture / m² and the average plastic strain is greater than 0.001, its development characteristics are judged to be "well-developed fractures with some plastic deformation." If the average stress concentration factor is greater than 1.5, it is judged to be "significant stress concentration and poor stability."

[0035] Furthermore, by quantitatively analyzing the characteristics of overburden strata under different mining conditions, the limitations of relying on experience to judge the development status of the strata were solved, providing data support for the subsequent screening of grouting bearing strata. The development characteristic parameters are the core basis for screening candidate bearing strata, which is consistent with the "three zones" analysis requirements of coal mine overburden.

[0036] In the embodiment of the present invention, the grouting bearing layer refers to a target layer that meets grouting conditions and can support the overlying rock layer.

[0037] In an embodiment of the present invention, the step of constructing the grouting bearing layer of the goaf according to the development characteristics includes: Mapping the development characteristics into the three-dimensional geomechanical model and outputting a horizon feature matrix; Screening the layers in the layer feature matrix based on preset layer conditions to obtain candidate bearing layer areas; Determining the boundary range of the grouting bearing layer according to a preset water-conducting fracture zone height algorithm; The grouting bearing layer position is determined in the bearing layer candidate area according to the boundary range.

[0038] Specifically, each development characteristic parameter (such as a fracture density of 1.2 fractures / m² and a stress concentration factor of 1.3 in a certain layer) was bound to the corresponding block unit coordinates in the three-dimensional geomechanical model. Data gridding was used to divide the continuous three-dimensional space into grid units of 10m×10m×5m. The average value of the development characteristic parameter in each grid unit was calculated (for example, the fracture densities of three block units in a certain grid were 1.1, 1.3, and 1.2 fractures / m², respectively, with an average value of 1.2 fractures / m²). A stratigraphic characteristic matrix was constructed with grid unit coordinates as rows and development characteristic parameters as columns. Preset layer conditions are screening criteria set based on the functional requirements of the reconstructed critical bearing layer. These primarily include the degree of fracture development, potential bearing capacity, and stability requirements. For example, "The reconstructed critical bearing layer must have a bearing capacity of 30-45 MPa," and "The target area can be selected within the fracture zone and the curved subsidence zone." For example, the predefined layer conditions are: a fracture density of 0.8-2.0 fractures / m² (to ensure grout permeability and sufficient space for cementation), a stress concentration factor ≤ 1.5 (to prevent the layer from being easily damaged by excessive stress), and the lithology of hard sandstone or limestone (the target layer is mostly hard sandstone). The layer characteristic matrix is ​​then traversed, and each grid cell is individually determined to see if it meets all the predefined conditions. For example, a grid cell with a fracture density of 1.5 fractures / m², a stress concentration factor of 1.2, and sandstone lithology is considered to meet the requirements. If another cell has a fracture density of 0.6 fractures / m² (below the lower limit), it is excluded. All grid cells that meet the conditions are spatially aggregated to form a continuous region, which is the candidate bearing layer area.

[0039] Specifically, the water-conducting fracture zone refers to the rock layer area in the overlying rock layer of the goaf that has fractures due to mining and may conduct water. Its height is the vertical distance from the top of the goaf to the upper limit of the fracture zone; the spatial range of the fracture zone is quantitatively determined based on the water fracture zone height prediction method; the boundary range of the grouting bearing layer refers to the upper and lower limit coordinates of the bearing layer in three-dimensional space, which is used to constrain the spatial position of the final layer. For example, the mining height of a coal mine is 5m, and the upper limit of the water-conducting fracture zone is 54.7m away from the top of the goaf. The absolute elevation is determined in combination with the buried depth of the goaf: if the elevation of the top of the goaf is -400m, the upper limit elevation of the water-conducting fracture zone is -400 + 54.7≈-345.3m. Based on the condition that the target layer can be selected 30m above the fracture zone, the lower boundary of the grouting bearing layer is determined to be -345.3m + 10m=-335.3m (avoiding the core area of ​​the fracture zone), and the upper boundary is -335.3m +20m=-315.3m (to ensure sufficient layer thickness) to form a boundary range; compare the boundary range with the spatial coordinates of the candidate bearing layer area, and intercept the portion of the candidate area within this vertical range. If the intercepted area is a continuous 2000㎡ (meeting engineering requirements) and the internal development characteristic parameters all meet the preset conditions (such as an average crack density of 1.3 / m² and a stress concentration factor of 1.1), it is judged to be valid, and the area is determined to be the grouting bearing layer, and its three-dimensional coordinate range is output.

[0040] Furthermore, the target grouting layer that meets the requirements can be accurately locked, solving the problems of "insufficient bearing capacity" or "ineffective grouting" caused by selecting the layer based on experience alone. The layer is accurately positioned by superimposing the candidate area and the boundary range, providing a clear spatial carrier for the subsequent grouting simulation parameter design.

[0041] S3. Analyze the crack development characteristics and layer stress distribution of the grouting bearing layer.

[0042] In the embodiment of the present invention, the crack development characteristics refer to the spatial characteristics such as the distribution density, direction, and connectivity of cracks in the grouting bearing layer; the layer stress distribution refers to the magnitude and change trend of the stress value within the layer.

[0043] In an embodiment of the present invention, the analysis of the crack development characteristics and layer stress distribution of the grouting bearing layer includes: Extracting crack density parameters, crack strike parameters and stress concentration factor parameters from the layer characteristic matrix according to the layer coordinates of the grouting bearing layer; generating a directed graph model of fracture connectivity based on the fracture density parameter and the fracture strike parameter; Determining the fracture development characteristics of the grouting bearing layer according to the path trend in the directed graph model of fracture connectivity; A layer stress gradient cloud map is generated based on the stress concentration factor parameters, and the layer stress distribution of the grouting bearing layer is determined according to the cloud map trend of the layer stress gradient cloud map.

[0044] Specifically, the crack density parameter refers to the number of cracks per unit area of ​​the grouting bearing layer, reflecting the density of the cracks; the crack strike parameter refers to the angle between the crack extension direction and the north direction, characterizing the spatial extension trend of the cracks; the stress concentration factor parameter refers to the ratio of the local stress value to the average stress value in the layer, which is used to measure the degree of stress concentration, that is, to clarify the three-dimensional coordinate range of the grouting bearing layer, and filter out the entries whose coordinates fall within this range in the layer characteristic matrix; extract the corresponding crack density parameters, crack strike parameters and stress concentration factor parameters from these entries. For example, in a coal mine grouting layer, the parameters corresponding to the coordinates (100,50,-320) are: crack density 1.5 / m², strike 35°, and stress concentration factor 1.2.

[0045] Specifically, the directed graph model of fracture connectivity is a graphical model used to describe the connection relationship between fractures, in which the endpoints of the fractures are nodes, and the extension direction of the fractures is the directed edge (the direction of the arrow is consistent with the fracture direction). The node density is determined based on the extracted fracture density parameter (the higher the density, the denser the nodes), and the direction of the directed edge is determined according to the fracture direction parameter (for example, for a fracture with a 35° direction, the arrow of the edge points in the 35° direction). Finally, a directed graph reflecting the interconnectedness of the fractures is constructed, and the extension direction and connectivity of most paths (for example, more than 70%) in the directed graph are analyzed. If the path mainly extends along the 30° direction and the connection rate between nodes exceeds 60%, the fracture development characteristics of the grouting bearing layer are judged to be "mainly 30° direction, with good connectivity"; if the path direction is messy and the connection rate is less than 30%, it is judged to be "dispersed direction, poor connectivity". A stratigraphic stress gradient cloud map visually displays stress variations within a stratigraphic layer through a color gradient. Blue typically indicates low stress (stress concentration factor <1.0), green indicates moderate stress (1.0 ≤ stress concentration factor ≤1.3), and red indicates high stress (stress concentration factor >1.3). Its generation and analysis steps include mapping the extracted stress concentration factor parameters onto a two-dimensional plane using coordinates and using an interpolation algorithm to generate the cloud map. Based on the color distribution trends in the cloud map (e.g., red areas are concentrated in the center of the stratigraphic layer, blue areas are distributed at the edges), the stratigraphic stress distribution characteristics (e.g., "stress concentrated in the center, stress flat at the edges") are determined, indicating that the overburden stress distribution affects the grouting effect.

[0046] Furthermore, the internal structure of the grouting layer can be clearly determined based on the crack development characteristics and layer stress distribution, providing a basis for the subsequent grouting simulation parameter design.

[0047] S4. Analyze the grouting simulation parameters of the grouting bearing layer according to the crack development characteristics and the layer stress distribution, and iteratively optimize the grouting simulation parameters based on the rheological characteristics of the grouting material.

[0048] In the embodiment of the present invention, the grouting simulation parameters refer to key indicators that need to be controlled during the grouting process, including grouting volume, grouting pressure, grouting position, etc.

[0049] In an embodiment of the present invention, the analyzing of the grouting simulation parameters of the grouting bearing layer according to the crack development characteristics and the layer stress distribution includes: Determining the number of horizontal layer groups of the grouting bearing layer according to the thickness of the grouting bearing layer and the grouting diffusion radius; Determine the grouting position corresponding to each layer in the horizontal layer group according to the crack development characteristics and the layer stress distribution; Calculating the fracture space volume of each layer in the horizontal stratification group according to the fracture connectivity in the fracture development characteristics; Calculating the grouting amount corresponding to the grouting position by the volume of the fracture space and the preset rock mass expansion coefficient, and determining the grouting pressure at the grouting position according to the layer stress distribution; The grouting amount, the grouting pressure and the grouting position are determined as grouting simulation parameters.

[0050] In detail, the number of horizontal stratification groups refers to the number of horizontal grouting layers into which the grouting bearing layer is divided in the vertical direction, which is used to realize multi-horizontal segmented grouting to ensure that the slurry evenly covers the target layer; the grouting diffusion radius refers to the maximum horizontal distance that the slurry can reach by natural diffusion in the rock formation cracks, which is determined by the properties of the grouting material (such as viscosity) and the permeability of the rock formation. The thickness of the grouting bearing layer is extracted from the geological data, and the grouting diffusion radius is determined through laboratory grouting simulation tests. The number of horizontal groupings can be determined according to the formula: number of horizontal stratification groups = layer thickness ÷ (2 × grouting diffusion radius). The grouting location refers to the specific spatial coordinates of the grouting holes in each horizontal layer. It needs to be determined in combination with the characteristics of fracture development (such as fracture density and connectivity) and the layer stress distribution (such as the degree of stress concentration) to improve the grouting efficiency and avoid the risk of grouting in areas with excessively high stress. That is, within the horizontal layer, priority should be given to areas with a fracture density ≥1.2 / m² and good connectivity. In such areas, the grouting is easy to diffuse and can form effective cementation. In combination with the layer stress distribution, avoid high-stress areas with a stress concentration factor >1.5 (to avoid rock stratum fracture due to pressure superposition during grouting), and select medium- and low-stress areas with a stress concentration factor ≤1.3. Grouting holes should be arranged in a 5 m × 5 m grid within the candidate area to ensure that the diffusion range of each grouting hole can cover the surrounding fracture-dense areas. Fracture connectivity refers to the degree of interconnection between fractures within a horizontal layer. Fracture space volume refers to the total volume of slurry that can be accommodated by all connected fractures within the layer. It is the basic parameter for calculating the grouting volume. The proportion of connected fractures to total fractures in the statistical model is calculated. The geometric parameters of the fractures in the layer are extracted through the three-dimensional geomechanical model. The volume of a single fracture is calculated according to the formula "single fracture volume = length × average width × average height" and then summed up. The fracture space volume = total fracture volume × fracture connectivity.

[0051] Specifically, the preset rock mass expansion coefficient refers to the ratio of the rock mass's volume after crushing to its original volume, which is used to compensate for volume changes caused by rock mass compression. The grouting volume refers to the volume of slurry required to fill the fracture space: Grouting volume = fracture space volume × preset rock mass expansion coefficient. Grouting pressure refers to the pressure applied during grouting and must be matched to the stratum stress to prevent slurry runoff or insufficient filling. If the stratum stress distribution is low (stress concentration factor ≤ 1.0), a lower pressure (e.g., 0.5-1 MPa) is used to prevent excessive slurry diffusion and lead to slurry runoff (e.g., lower grouting pressure in the lower stratum is used to seal fractures). If the stratum stress distribution is low (1.0 < stress concentration factor ≤ 1.3), a conventional pressure (e.g., 1.5-2 MPa) is used to ensure sufficient slurry filling. If the stratum stress distribution is high (stress concentration factor > 1.3), a higher pressure (e.g., 2-3 MPa) is used to overcome rock mass stress and ensure slurry penetration (in accordance with the requirement of "pressure grouting, different pressures for different strata"). Then, the grouting position coordinates (e.g., X=100, Y=50, Z=-320), corresponding grouting volume (108m³), and grouting pressure (1.8MPa) of each horizontal layer are bound to form a structured parameter table to determine the grouting simulation parameters.

[0052] Furthermore, by quantitatively calculating and determining precise grouting simulation parameters, we address the issues of insufficient grouting or excessive waste caused by reliance on experience, meeting the requirements of precise pressure grouting reinforcement. Grouting simulation parameters provide the data foundation for multi-level grouting sequence and process design, forming a technical chain from feature analysis to parameter calculation to solution implementation.

[0053] In the embodiment of the present invention, the rheological characteristics of the grouting material refer to its flow and deformation characteristics under the action of external force, which are specifically manifested as the change pattern of viscosity with shear rate, time or temperature. By dynamically optimizing the grouting pressure, the problem of insufficient coverage or excessive grouting caused by fixed parameters is solved, making the slurry coverage more precise.

[0054] In an embodiment of the present invention, the iterative optimization of the grouting simulation parameters based on the rheological characteristics of the grouting material includes: Extracting a dynamic viscosity function from the rheological characteristics according to the crack development characteristics of the grouting bearing layer; generating a slurry diffusion control equation based on the dynamic viscosity function and the layer stress distribution; performing a finite difference solution operation on the slurry diffusion control equation and outputting a grouting coverage radius; Calculating a pressure compensation gradient based on a deviation between the grouting coverage radius and a preset target coverage area; The grouting pressure parameters are iteratively updated based on the pressure compensation gradient, and when the coverage radius deviation of a preset number of iterations is less than or equal to a preset deviation threshold, the optimized grouting simulation parameters are output.

[0055] Specifically, the dynamic viscosity function is a mathematical expression that describes the change of the viscosity of the grouting material with the shear rate. The rheological test of the grouting material (pre-set ratio: fly ash 30%, 1-10mm gangue 40%, cement 20%, accelerator 3%) was carried out by a rotational viscometer to measure the viscosity of the grouting material at different shear rates (e.g. 10s -1 , 50s -1 , 100s -1 ) under the viscosity value, the rheological curve is obtained; if the density of the cracks in the grouting layer is 1.5 / m² and the connectivity is 0.7 (medium connectivity), the interval that meets the medium shear thinning characteristics is selected from the rheological curve, and the data of this interval is fitted by the least squares method to obtain the dynamic viscosity function ,in is the shear rate.

[0056] Specifically, the slurry diffusion control equation is a mathematical model that describes the relationship between the slurry diffusion distance in the fracture and the grouting pressure, material viscosity, and layer stress. The slurry diffusion control equation is: ,in is the slurry diffusion distance, is the grouting pressure, is the slurry diffusion velocity, 0.02 is the empirical coefficient, then the greater the pressure, the smaller the stress, the lower the viscosity, the longer the diffusion distance, and then the continuous control equation is discretized into an algebraic equation on the grid nodes. The numerical method of the slurry diffusion distance of each node is obtained by iterative calculation. The grouting coverage radius refers to the maximum horizontal distance that the slurry can diffuse under a certain grouting pressure. It is a key indicator to measure the grouting effect. The control equation is discretized into a difference format as follows: ,in For the Step diffusion distance, For the The diffusion speed was calculated by iteration for 500 steps (simulating 500s diffusion) to obtain the diffusion distance of each grid node, and the maximum value was taken as the grouting coverage radius.

[0057] Furthermore, the preset target coverage area refers to the minimum coverage radius set to ensure that the cracks are completely filled. The difference between the actual coverage radius and the target radius is calculated as the deviation. The pressure compensation gradient is determined by the increase in grouting pressure required to compensate for the unit deviation. For example, the pressure-coverage sensitivity of the grouting material is "for every 0.1 MPa increase in pressure, the coverage radius increases by 0.2 m", and the deviation is 0.5 m. Therefore, the pressure compensation gradient is 0.5 MPa / m, and the total compensation pressure is 0.25 MPa; iterative update refers to a cyclic process of adjusting the grouting pressure multiple times, recalculating the coverage radius, and verifying the deviation. The preset number of iterations (such as 3 times) and the deviation threshold (such as 0.1 m) are to balance the calculation accuracy and efficiency and ensure the convergence of parameter optimization.

[0058] Furthermore, by dynamically optimizing the grouting pressure, the problem of insufficient coverage or excessive grouting caused by fixed parameters is solved, making the slurry coverage more precise.

[0059] S5. Dynamically generate a multi-level layered grouting simulation scheme for the grouting bearing layer using the optimized grouting simulation parameters.

[0060] In an embodiment of the present invention, the multi-level layered grouting simulation plan is a construction guidance document including a grouting sequence and parameters of each step (position, pressure, amount, material ratio).

[0061] In an embodiment of the present invention, the method of dynamically generating a multi-level layered grouting simulation scheme for the grouting bearing layer using the optimized grouting simulation parameters includes: Dividing the grouting bearing layer into annular areas with increasing radial distances, and determining the grouting execution order according to the annular areas; Determining the order of executing grouting up and down according to the order of the layers of the grouting bearing layer; Generate a grouting sequence according to the grouting execution order of distance and the grouting execution order of top and bottom; Performing a fissure plugging simulation operation on the grouting area below the grouting bearing layer to construct a virtual boundary of the grouting isolation layer; A grouting layer simulation unit is constructed according to the virtual boundary of the grouting layer. When the strength of the grouting layer simulation unit meets the preset strength condition, a multi-level layered grouting simulation scheme is generated according to the grouting sequence and the optimized grouting simulation parameters.

[0062] Specifically, the annular zones are concentric ring-shaped zones centered on the grouting main well, divided by increasing radial distance. This ensures uniform grouting coverage. The radial distance is the horizontal straight-line distance between the boundary of each annular zone and the main well. Specifically, the main well is located, with this as the center. Based on the grouting diffusion radius and the stratum area, n annular zones are divided with increasing radial distance. The division is based on the principle that "each ring width does not exceed twice the diffusion radius" (to ensure that adjacent rings do not overlap). The grouting sequence is defined as "1st ring → 2nd ring → 3rd ring" to fill distal fractures first, thereby preventing excessive grouting from converging proximally and reducing the risk of grout leakage. The stratum sequence refers to the vertical arrangement of the grouting bearing layers (e.g., lower, middle, upper) by vertical depth. This is determined by the Z coordinate of the 3D geomechanical model (the deeper the depth, the lower the stratum). The top-to-bottom grouting sequence refers to the order in which grouting is performed from bottom to top. The top-to-bottom grouting sequence is determined as "lower layer → middle layer → upper layer." This is based on the idea that grouting in the lower layer can seal underlying fractures, forming a simulated grouting barrier and preventing grout from leaking into the underlying goaf's collapse zone. The grouting sequence combines the near-far grouting sequence with the top-to-bottom grouting sequence to create a specific sequence of construction steps. This guides the logical sequencing of multi-level layered grouting, such as near-far: 1st ring → 2nd ring → 3rd ring; top-to-bottom: lower layer → middle layer → upper layer. These combinations create a grouting sequence.

[0063] Specifically, the crack plugging simulation operation refers to predicting the effect of slurry solidification and crack plugging after grouting in the lower layer through numerical simulation software, that is, inputting the parameters of the lower layer grouting area: grouting pressure 0.5MPa, grouting volume 80m³, slurry solidification time 6 hours, crack density 1.5 / m², and calculating the slurry diffusion path and strength distribution after solidification through simulation software: slurry fills the 1st to 3rd ring cracks in the lower layer under a pressure of 0.5MPa, 6 After 24 hours, the stone body strength reaches 3MPa (meeting the strength requirements of the mortar layer simulation unit), and the closed area boundary formed is Z=-330-320m, X=70-130m, Y=30-90m, which is the virtual boundary of the mortar layer simulation unit. The lower layer grouting is constructed according to the virtual boundary of the mortar layer simulation unit: grouting is carried out in the 1st to 3rd rings of the lower layer according to the sequence 1-3 steps, using fast-setting materials (cement content 20%, fast-setting agent 3%), and the slurry diffusion is monitored in real time (deviation from the simulation path ≤0.5m). After 6 hours, sampling is carried out through drilling. The stone body strength was measured, and the result was 3.2MPa (≥3MPa, meeting the preset conditions), confirming the formation of the mortar barrier layer simulation unit, and then generating a multi-level layered grouting simulation plan: using the grouting sequence as the framework, binding the parameters of each step: lower layer: pressure 0.5MPa, quick-setting material (accelerator 3%), volume 80-100m³; middle layer: pressure 2MPa, conventional material (accelerator 1%), volume 95-110m³; upper layer: pressure 2.5MPa, high-strength material (cement content 30%), volume 90-105m³.

[0064] For example, the multi-level grouting method involves segmented and layered grouting, with grouting performed from far to near and from bottom to top, based on the main grouting well. The initial grouting material in the lower layer must be used to quickly seal cracks and form a grouting layer simulation unit, depending on the intended use. The grouting pressure is low, and the grouting material is required to have a fast setting rate. After the lower layer is grouted from far to near to form a stable grouting layer simulation unit, grouting from far to near is started in the upper layer. The grouting pressure is increased to the standard grouting pressure, and the grouting material ratio is adjusted. After grouting of the current layer is completed, grouting of the upper layer from far to near is started until all layers are grouted.

[0065] Furthermore, layered and ordered grouting and protection of grouting layer simulation units, annular area division and layer sequence provide the basis for the grouting sequence. The simulation and construction of the grouting layer simulation unit ensure that the sequence can be executed safely. The final solution is the comprehensive application of all the aforementioned optimization parameters.

[0066] S6. Generate a digital trajectory of the grouting drilling holes in the grouting bearing layer according to the multi-level layered grouting simulation scheme, and generate a grouting control simulation instruction according to the digital trajectory.

[0067] In the embodiment of the present invention, the digital trajectory refers to a smooth curve fitted according to a set of control points, which is used to guide directional drilling construction and ensure that the grouting pipe reaches each grouting position accurately.

[0068] In an embodiment of the present invention, the step of generating a digital trajectory of the grouting borehole in the grouting bearing layer according to the multi-level layered grouting simulation scheme includes: Generating a preliminary drilling axis of the grouting bearing layer according to the grouting position in the multi-level layered grouting simulation scheme; Analyzing the drillability of the rock formation in the preliminary drilling axis to obtain a target risk marker segment; performing a trajectory error compensation operation on the preliminary drilling axis according to the target risk marker segment and preset gyro inclinometer data to obtain a drilling control point set; A digital trajectory of the grouting bearing layer is generated according to the drilling control point set.

[0069] In detail, the grouting position refers to the three-dimensional coordinates of each grouting point specified in the multi-level layered grouting simulation plan, including the horizontal annular area coordinates and the vertical layer coordinates; the preliminary drilling axis refers to the straight path from the ground drilling and injection station to the grouting position, which is used to preliminarily plan the direction of the borehole, that is, to determine the coordinates of the ground drilling and injection station as the starting point of the borehole. For each grouting position, the spatial straight line equation is used to calculate the path from the starting point to the end point to obtain the angular parameters of the preliminary drilling axis (such as a depression angle of 75° and an azimuth angle of 30°).

[0070] Specifically, the drillability of a rock formation refers to the ease with which a hole can be penetrated, and is usually expressed as a drillability grade (1-10, with the higher the grade, the more difficult it is to drill). The rock formation type and the corresponding drillability grade that the preliminary borehole axis passes through are extracted from the lithologic distribution data of the 3D geomechanical model. For example, the axis in the Z=-100--150m section is limestone (drillability grade 7), and the Z=-200--250m section is sandstone with dense fractures (fracture density 2.5 fractures / m²). These sections are marked and defined as target risk marker sections. For these target risk marker sections, a preset compensation coefficient is set: at drillability grade 7, the deflection angle is adjusted by 0.5° for every 10m of drilling to avoid excessive deflection. Combined with the gyroscopic inclination data (e.g., the actual deflection angle is 3°, exceeding the allowable error of ±2°), the compensation amount is calculated: an adjustment of 0.3° in the opposite direction is required to keep the deflection within 2°. Every 50m on the compensated axis, the compensation coefficient is set to 0.5°. Set a control point and record its three-dimensional coordinates to form a drilling control point set, ensure that the lines connecting the points are smooth, and then fit the control points in the drilling control point set to obtain a digitized trajectory.

[0071] Furthermore, the grouting control simulation instructions are a set of specific instructions for guiding drilling and grouting operations, including drilling parameters (angle, speed) and grouting simulation parameters (pressure, quantity, material ratio), such as drilling stage instructions: for each control point, clearly define the drilling angle, drilling speed, and drill bit type; grouting stage instructions: according to the grouting sequence, the grouting pressure of the first ring of the lower layer is 0.5MPa, the grouting volume is 80m³, and the material is quick-setting type (3% quick-setting agent); the pressure of the second ring of the middle layer is 2MPa, the volume is 95m³, and the material is conventional type (1% quick-setting agent); monitoring instructions: real-time monitoring of the orifice pressure (deviation ≤0.1MPa) and grouting volume (cumulative error ≤5%). If the pressure drops suddenly (such as <0.3MPa), the "stop grouting + seal weak surface" instruction is triggered.

[0072] S7. Perform a multi-level grouting simulation operation on the grouting bearing layer according to the grouting control simulation instruction, and output a multi-level grouting simulation result.

[0073] In the embodiment of the present invention, the multi-level grouting simulation result refers to a comprehensive evaluation of the grouting effect, such as coverage, filling density, and whether the bearing layer strength requirement is met.

[0074] In an embodiment of the present invention, performing a multi-level grouting simulation operation on the grouting bearing layer according to the grouting control simulation instruction and outputting a multi-level grouting simulation result includes: monitoring the orifice pressure and cumulative grouting volume of the grouting bearing layer in real time according to the grouting control simulation instruction; If the instantaneous rising rate of the orifice pressure exceeds a preset rising threshold and the accumulated grouting volume reaches a preset first grouting threshold, triggering a stop grouting simulation instruction in the grouting control simulation instruction; If the orifice pressure shows a downward trend within a preset time range or the accumulated grouting volume exceeds a preset second grouting threshold, triggering the emergency positioning simulation instruction in the grouting control simulation instruction; Scan the overburden weak surface of the grouting bearing layer according to the emergency positioning simulation instruction to obtain a slurry leakage positioning point, and execute the plugging material injection simulation instruction according to the slurry leakage positioning point; monitoring whether the orifice pressure shows a stable trend after the plugging material injection simulation instruction is executed, and triggering a resume grouting simulation instruction in the grouting control simulation instruction when the orifice pressure shows a stable trend; A grouting visualization diagram is generated according to the stop grouting simulation instruction, the emergency positioning simulation instruction and the resume grouting simulation instruction, and a multi-level grouting simulation result is determined through the grouting visualization diagram.

[0075] Specifically, orifice pressure refers to the slurry pressure at the grouting pipe outlet, reflecting the diffusion resistance of the slurry in the crack. The cumulative grouting volume refers to the total volume of slurry injected from the start of grouting to the current moment, and is used to determine the degree of crack filling. Pressure sensors and electromagnetic flowmeters are installed at the grouting pipe orifices to collect real-time pressure and flow data. The instantaneous rate of rise of orifice pressure refers to the change in pressure per unit time, reflecting the degree of saturation of the crack with slurry. The preset rising threshold is a critical value set based on the slurry solidification characteristics. The first grouting threshold refers to the theoretically calculated amount of slurry required to fill the crack. When the instantaneous rate of rise of orifice pressure exceeds the preset rising threshold and the cumulative grouting volume reaches the preset first grouting threshold, the crack is deemed fully filled. The control system automatically issues a command to stop the grouting simulation, shuts down the grouting pump, and records the current status (e.g., "Grouting stopped at 10:30, pressure 2.0 MPa, volume 108 m³").

[0076] Specifically, a downward trend in orifice pressure refers to a continuous decrease in pressure within a preset time range, which may lead to slurry loss (slurry leakage) due to crack penetration. The preset second grouting threshold is the maximum allowable grouting volume. Exceeding this value indicates that the slurry is not effectively filled (slurry leakage may occur). The control system then triggers an emergency positioning simulation command and automatically starts a geological radar (detection accuracy of 0.5m) to scan the grouting bearing layer, focusing on identifying areas with dense fractures. The geological radar scan shows an abnormal reflection signal in area A (dense fractures). Combined with borehole television observations, the slurry leakage location point is determined. The overburden weak plane refers to an area with dense fractures and low strength in the overburden layer, which is the main channel for slurry leakage. The slurry leakage location point is the specific three-dimensional coordinate of the weak plane where slurry leakage occurs. The control system then sends a command to inject plugging material into the location point through the branch grouting pipe and monitors whether the orifice pressure shows a stable trend after the execution of the plugging material injection simulation command. That is, if the fluctuation amplitude of the orifice pressure within the preset time is less than the preset fluctuation threshold (for example, stable at 1.7-1.8MPa), it indicates that the plugging is effective and the fracture leakage channel has been closed. The resume grouting simulation instruction refers to the instruction to restart the grouting operation. The control system sends a resume instruction, the grouting pump restarts, and grouting continues according to the original parameters, and the current cumulative amount is recorded (85+5=90m³ has been injected, and 18m³ remains).

[0077] For example, the ground directional drilling grouting method is a pressurized grouting method, which requires real-time monitoring of the grouting pressure and grouting volume. If the orifice pressure rises rapidly and the grouting volume reaches the preset value, grouting is stopped; if the orifice pressure remains stable, grouting is continued; if the orifice pressure drops rapidly or the grouting volume exceeds the preset value, grouting may occur, and grouting must be stopped immediately. In the event of grouting, the grouting location must be identified, and the weak surface of the overburden must be sealed before normal grouting can be carried out. In the event of grouting leakage, the leakage location must be observed by drilling and then sealed. Grouting can be resumed after the leakage location is sealed.

[0078] Furthermore, the grouting visualization diagram refers to the slurry diffusion cloud map, pressure distribution contour map and instruction execution timeline generated by computer software. The visualization diagram is generated according to different instructions, such as the stop instruction diagram: showing the pressure surge point (10:30), the cumulative volume 108m³, and the slurry diffusion cloud map covering the target area (red indicates the filling area); the emergency instruction diagram: marking the slurry running positioning points (97m, 57m, -325m), and showing the pressure change curve before and after plugging; the recovery instruction diagram: showing the pressure stable section (10:45-10:50) and the remaining slurry diffusion path.

[0079] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0080] Therefore, no matter from which point of view, the embodiments should be regarded as illustrative and non-restrictive, and the scope of the present invention is not limited only according to the above description, and it is intended that all changes within the meaning and scope of equivalent elements falling within the scope of protection are included in the present invention.

[0081] The embodiments of the present application can acquire and process relevant data based on artificial intelligence technology. Artificial intelligence (AI) refers to the theories, methods, techniques, and application systems that use digital computers or machines controlled by digital computers to simulate, extend, and expand human intelligence, perceive the environment, acquire knowledge, and use that knowledge to achieve optimal results.

[0082] Furthermore, it is clear that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or systems recited in a system claim may also be implemented by a single unit or system through software or hardware. Terms such as "first" and "second" are used to indicate names and do not imply any particular order.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for optimizing multi-level grouting design in overburden based on computer simulation, characterized in that: The method comprises: Collecting geological exploration data of the goaf, digitally processing the geological exploration data, and constructing a three-dimensional geomechanical model of the goaf; Performing finite element numerical simulation on the three-dimensional geomechanical model, calculating the development characteristics of each layer in the overburden layer of the goaf, and constructing the grouting bearing layer layer of the goaf according to the development characteristics; Analyze the crack development characteristics and layer stress distribution of the grouting bearing layer; Analyzing the grouting simulation parameters of the grouting bearing layer according to the crack development characteristics and the layer stress distribution, and iteratively optimizing the grouting simulation parameters based on the rheological characteristics of the grouting material; Dynamically generate a multi-level layered grouting simulation scheme for the grouting bearing layer using the optimized grouting simulation parameters; Generating a digital trajectory of the grouting borehole in the grouting bearing layer according to the multi-level layered grouting simulation scheme, and generating a grouting control simulation instruction according to the digital trajectory; A multi-level grouting simulation operation is performed on the grouting bearing layer according to the grouting control simulation instruction, and a multi-level grouting simulation result is output.

2. The computer simulation-based multi-level grouting design optimization method for overburden according to claim 1, characterized in that: The digital processing of the geological exploration data to construct a three-dimensional geomechanical model of the goaf includes: Performing a drilling lithology identification operation on the geological exploration data to generate lithology distribution data of overlying rock layers in the goaf; The fracture zone boundary calibration operation is performed on the overlying rock layer of the goaf to obtain the coordinate range of the subsidence zone; Performing spatial interpolation calculation on the overburden strata based on the coordinate range of the subsidence zone to generate a density cloud map of the structural surface of the overburden strata; Constructing a block discrete network model with fault constraints on the goaf according to the density cloud map and the lithology distribution data; The block discrete network model is used as a three-dimensional geomechanical model of the goaf.

3. The computer simulation-based overburden multi-level grouting design optimization method according to claim 2, characterized in that: The finite element numerical simulation of the three-dimensional geomechanical model is performed to calculate the development characteristics of each layer in the overburden layer of the goaf, including: Loading rock mass mechanical parameters corresponding to the three-dimensional geomechanical model based on the geological exploration data, and constructing an elastic-plastic constitutive model of the overburden layer above the goaf according to the rock mass mechanical parameters; Dividing the three-dimensional geomechanical model into grid units according to the elastic-plastic constitutive model of the overburden rock to obtain a grid unit group; Multi-condition numerical simulation is performed on the grid unit group to obtain development characteristic parameters of each layer in the overburden layer, and the development characteristics of each layer in the overburden layer are determined based on the development characteristic parameters.

4. The computer simulation-based overburden multi-level grouting design optimization method according to claim 1, characterized in that: The step of constructing the grouting bearing layer of the goaf according to the development characteristics includes: Mapping the development characteristics into the three-dimensional geomechanical model and outputting a horizon feature matrix; Screening the layers in the layer feature matrix based on preset layer conditions to obtain candidate bearing layer areas; Determining the boundary range of the grouting bearing layer according to a preset water-conducting fracture zone height algorithm; The grouting bearing layer position is determined in the bearing layer candidate area according to the boundary range.

5. The computer simulation-based overburden multi-level grouting design optimization method according to claim 4, characterized in that: The analysis of the crack development characteristics and layer stress distribution of the grouting bearing layer includes: Extracting crack density parameters, crack strike parameters and stress concentration factor parameters from the layer characteristic matrix according to the layer coordinates of the grouting bearing layer; generating a directed graph model of fracture connectivity based on the fracture density parameter and the fracture strike parameter; Determining the fracture development characteristics of the grouting bearing layer according to the path trend in the directed graph model of fracture connectivity; A layer stress gradient cloud map is generated based on the stress concentration factor parameters, and the layer stress distribution of the grouting bearing layer is determined according to the cloud map trend of the layer stress gradient cloud map.

6. The computer simulation-based overburden multi-level grouting design optimization method according to claim 1, characterized in that: The analyzing the grouting simulation parameters of the grouting bearing layer according to the crack development characteristics and the layer stress distribution includes: Determining the number of horizontal layer groups of the grouting bearing layer according to the thickness of the grouting bearing layer and the grouting diffusion radius; Determine the grouting position corresponding to each layer in the horizontal layer group according to the crack development characteristics and the layer stress distribution; Calculating the fracture space volume of each layer in the horizontal stratification group according to the fracture connectivity in the fracture development characteristics; Calculating the grouting amount corresponding to the grouting position by the volume of the fracture space and the preset rock mass expansion coefficient, and determining the grouting pressure at the grouting position according to the layer stress distribution; The grouting amount, the grouting pressure and the grouting position are determined as grouting simulation parameters.

7. The computer simulation-based overburden multi-level grouting design optimization method according to claim 1, characterized in that: The iterative optimization of the grouting simulation parameters based on the rheological characteristics of the grouting material includes: Extracting a dynamic viscosity function from the rheological characteristics according to the crack development characteristics of the grouting bearing layer; generating a slurry diffusion control equation based on the dynamic viscosity function and the layer stress distribution; performing a finite difference solution operation on the slurry diffusion control equation and outputting a grouting coverage radius; Calculating a pressure compensation gradient based on a deviation between the grouting coverage radius and a preset target coverage area; The grouting pressure parameters are iteratively updated based on the pressure compensation gradient, and when the coverage radius deviation of a preset number of iterations is less than or equal to a preset deviation threshold, the optimized grouting simulation parameters are output.

8. The computer simulation-based overburden multi-level grouting design optimization method according to claim 1, characterized in that: The method of dynamically generating a multi-level layered grouting simulation scheme for the grouting bearing layer by using the optimized grouting simulation parameters includes: Dividing the grouting bearing layer into annular areas with increasing radial distances, and determining the grouting execution order according to the annular areas; Determining the order of executing grouting up and down according to the order of the layers of the grouting bearing layer; Generate a grouting sequence according to the grouting execution order of distance and the grouting execution order of top and bottom; Performing a fissure plugging simulation operation on the grouting area below the grouting bearing layer to construct a virtual boundary of the grouting isolation layer; A grouting layer simulation unit is constructed according to the virtual boundary of the grouting layer. When the strength of the grouting layer simulation unit meets the preset strength condition, a multi-level layered grouting simulation scheme is generated according to the grouting sequence and the optimized grouting simulation parameters.

9. The computer simulation-based overburden multi-level grouting design optimization method according to claim 1, characterized in that: The step of generating a digital trajectory of the grouting boreholes in the grouting bearing layer according to the multi-level layered grouting simulation scheme includes: Generating a preliminary drilling axis of the grouting bearing layer according to the grouting position in the multi-level layered grouting simulation scheme; Analyzing the drillability of the rock formation in the preliminary drilling axis to obtain a target risk marker segment; performing a trajectory error compensation operation on the preliminary drilling axis according to the target risk marker segment and preset gyro inclinometer data to obtain a drilling control point set; A digital trajectory of the grouting bearing layer is generated according to the drilling control point set.

10. The computer simulation-based overburden multi-level grouting design optimization method according to claim 1, characterized in that: The performing of a multi-level grouting simulation operation on the grouting bearing layer according to the grouting control simulation instruction and outputting a multi-level grouting simulation result includes: monitoring the orifice pressure and cumulative grouting volume of the grouting bearing layer in real time according to the grouting control simulation instruction; If the instantaneous rising rate of the orifice pressure exceeds a preset rising threshold and the accumulated grouting volume reaches a preset first grouting threshold, triggering a stop grouting simulation instruction in the grouting control simulation instruction; If the orifice pressure shows a downward trend within a preset time range or the accumulated grouting volume exceeds a preset second grouting threshold, triggering the emergency positioning simulation instruction in the grouting control simulation instruction; Scan the overburden weak surface of the grouting bearing layer according to the emergency positioning simulation instruction to obtain a slurry leakage positioning point, and execute the plugging material injection simulation instruction according to the slurry leakage positioning point; monitoring whether the orifice pressure shows a stable trend after the plugging material injection simulation instruction is executed, and triggering a resume grouting simulation instruction in the grouting control simulation instruction when the orifice pressure shows a stable trend; A grouting visualization diagram is generated according to the stop grouting simulation instruction, the emergency positioning simulation instruction and the resume grouting simulation instruction, and a multi-level grouting simulation result is determined through the grouting visualization diagram.

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