Method for determining key layer of filling false roof of high drift

Abstract

The invention discloses a high-drift filling false roof key layer determination method, which belongs to the technical field of metal mining, and comprises the following steps: constructing a filling false roof mechanical model based on a thick plate theory, analyzing filling false roof stability influence factors based on a numerical simulation means, and determining a filling false roof key layer. Evaluating influence factors of the influence factor set by adopting a combined weighted VIKOR comprehensive evaluation method, taking a scheme with a minimum decision index value as an optimal false roof filling scheme, and outputting optimal false roof filling parameters; in the embodiment of the invention, a combined weighted VIKOR comprehensive evaluation method is constructed, safety indexes and economic indexes are organically combined, and a set of comprehensive evaluation system is established to determine the optimal parameters meeting comprehensive requirements, so that the filling body parameter optimization result can ensure the safety of a stope, and the cost of per ton of mine exploitation can be effectively reduced; the limitation of a traditional single safety criterion is overcome, and the method is more scientific and practical.

Description

Technical Field

[0001] The invention belongs to the technical field of metal mining, and in particular relates to a method for determining a key layer of a filling false roof in a high-access route. Background Art

[0002] In the mining of deep, fractured ore bodies, filling false roofs can effectively prevent premature collapse of the upper part of the stope, avoiding damage to workers and equipment, while also improving resource recovery. As a core technology for ensuring stope stability and operational safety, parameter optimization of filling false roofs has a significant impact on resource recovery, production costs, and mine economic benefits. For some low-grade, fractured ore bodies, conventional approach-fill mining methods cannot achieve safe and economic recovery. Therefore, it is necessary to improve and optimize existing mining methods and conduct in-depth research on mining methods and process technologies. While ensuring safety, the use of high-access-fill mining methods can increase mining efficiency and improve economic benefits. Currently, domestic and foreign scholars have conducted extensive research on the stability of filling false roofs, primarily using theoretical models (such as simply supported beam and thin plate theory), numerical simulations (such as FLAC3D), and engineering analogies. By analyzing the relationship between false roof thickness, strength, and safety factor, key layer parameters are determined, and then the key layer of the filling false roof is determined.

[0003] However, determining the key layer for the false roof filling must not only ensure stability and safety during stope recovery, but also ensure economic efficiency during mining operations. The higher the design strength and thickness of the key layer, the greater the stability of the false roof. However, this also increases the amount of cementitious materials and costs required to construct the false roof. For some difficult-to-mining and low-grade deposits, this becomes uneconomical to exploit. Therefore, determining the key layer for the false roof filling, while ensuring safe mining, is crucial for mining operations.

[0004] However, existing technologies still have the following limitations:

[0005] 1) Existing methods for determining the thickness or strength of the critical layer of the false roof are mostly based on theoretical models. However, due to the different mining technologies and complex hydrogeological characteristics of each mine, it is difficult to obtain a method for determining the thickness and strength of the critical layer that is sufficiently consistent with the needs of the corresponding mine by relying on theoretical model calculations.

[0006] 2) Existing methods for determining the critical layer of a false roof often focus solely on the impact of the thickness or strength parameters of the critical layer on its safety and stability. Based on this, the critical layer thickness and strength designed are the minimum limits for ensuring stope safety. However, in actual mining operations, the thickness and strength of the critical layer are coupled with the strength of the common layer, all of which have a positive impact on overall stability. Existing methods fail to systematically explore the synergistic effects of multiple parameters and the degree of influence of each parameter, resulting in unscientific parameter combination design.

[0007] 3) The existing method for determining the critical layer of the filling false roof is dominated by a single safety criterion, and a comprehensive evaluation system that covers both safety and economic benefits has not been established. As a result, the final determination of the filling false roof parameters is difficult to take into account both safety and economic rationality.

[0008] To address the above problems, we proposed a method for determining the critical layer of the filling false roof with high access. Summary of the Invention

[0009] The purpose of the present invention is to address the deficiencies of the prior art and provide a method for determining the key layer of a high-access filling false roof.

[0010] The present invention is implemented as follows: a method for determining a key layer of a filling false roof of a high-access route, the method comprising:

[0011] S10, obtaining basic mechanical parameters of the filling body based on a basic mechanical property test of the filling body;

[0012] S20, load the basic mechanical parameters of the filling body, construct the filling false roof mechanical model based on the thick plate theory to obtain the analytical solution of the tensile stress component, verify the stability of the filling false roof in combination with the safety factor, and output the filling false roof stability analysis results;

[0013] S30, obtaining the results of the filling false roof stability analysis, analyzing the factors affecting the filling false roof stability based on numerical simulation, determining the significance level of the influence of the factors on the filling false roof stability, and obtaining a set of influencing factors including the degree of influence;

[0014] S40, loading the influencing factor set, pre-constructing the VIKOR comprehensive evaluation method based on combined weighting, using the VIKOR comprehensive evaluation method based on combined weighting to evaluate and optimize the influencing factors of the influencing factor set, taking the solution with the smallest decision index value as the optimal solution for filling the false roof, and outputting the optimal parameters for filling the false roof.

[0015] The method for obtaining basic mechanical parameters of a filling body based on a basic mechanical property test of the filling body comprises:

[0016] S101, determining the filling type and foundation mechanical parameter type, wherein the filling type includes cement, river sand, and waste rock, and the foundation mechanical parameter type includes density, tensile strength, internal friction angle, cohesion, elastic modulus, and Poisson's ratio;

[0017] S102, conduct physical and chemical property tests on the filling material, including water content, specific gravity, loose / tight bulk density, porosity, and particle size distribution;

[0018] S103, preparing a filling slurry based on the filling slurry ratio scheme, injecting the prepared slurry into a test mold, letting it stand for 24 hours, taking out the filling body sample and marking it with the group and date, placing the filling body sample in a standard curing box, and curing it to the corresponding age;

[0019] S104: Perform uniaxial compression and uniaxial tensile tests on the filling sample, use Origin to draw a stress-strain curve, divide it into elastic stages, and perform linear fitting. The obtained slope is the elastic modulus of the filling.

[0020] The method for constructing a filling false roof mechanical model based on thick plate theory to obtain an analytical solution for tensile stress components includes:

[0021] S201, pre-constructing a filling false roof model, simplifying the filling false roof model into a four-side simply supported structure, and constructing a filling false roof mechanical model in combination with thick plate model theory;

[0022] S202, obtaining analytical solutions for the maximum tensile stress along the x-axis and y-axis directions through a filling false roof mechanical model;

[0023] S203, verifying the stability of the filling false roof through numerical simulation results, and outputting the filling false roof stability analysis results.

[0024] The method for analyzing factors affecting the stability of a filling false roof based on numerical simulation means includes:

[0025] S301, design an orthogonal experiment plan based on mine requirements and construct an orthogonal experiment table;

[0026] S302, constructing a numerical model of the mine stope;

[0027] S303, setting boundary conditions and initial stress field;

[0028] S304, using numerical simulation to analyze the excavation process, analyze the displacement distribution, maximum and minimum stress distribution, and plastic zone distribution, and obtain analysis results of the displacement distribution, maximum and minimum stress distribution, and plastic zone distribution;

[0029] S305, using SPSS software to perform variance analysis and range analysis on the analysis results, analyze the influence relationship of the influencing factors on the stability of the filling false roof, determine the significance level of the influence of the influencing factors on the stability of the filling false roof, and obtain an influencing factor set including the degree of influence.

[0030] The method for evaluating the influencing factors of the influencing factor set using the combined weighted VIKOR comprehensive evaluation method includes:

[0031] S401, load the influencing factor set, decompose the decision problem based on the AHP method, subjectively weight the influencing factors, and obtain the subjective weights of the influencing factors;

[0032] S402, objectively weighting the influencing factors based on the CRITIC method to obtain the objective weights of the influencing factors;

[0033] S403, obtaining the subjective weight and objective weight of the influencing factors, and combining the subjective weight and the objective weight to obtain a combined weight;

[0034] S404: Use the VIKOR method to convert the problem's indicators and solutions into a decision matrix. After normalization, perform combined weighting. After determining the positive and negative ideal solutions, calculate the distance to the optimal solution and the group utility value, individual regret value, and decision indicator value. The solution with the smallest decision indicator value is the optimal solution for filling the false top, and output the optimal parameters for filling the false top.

[0035] When evaluating the influencing factors of the influencing factor set using the combined weighted VIKOR comprehensive evaluation method, AHP and CRITIC are combined for weighting. A multi-criteria compromise solution ranking method (VIKOR) is then used to conduct a multi-objective decision analysis on evaluation indicators with different weights to determine the optimal filling and false roof solution. This combined weighting of AHP and CRITIC combines the advantages of both, taking into account the professional judgment of experts and utilizing objective data information. This further improves the scientific nature and reliability of the weighting results and provides a more solid weighting foundation for subsequent evaluation work. The multi-criteria compromise solution ranking method (VIKOR) is used to conduct a multi-objective decision analysis on evaluation indicators with different weights to determine the optimal filling and false roof solution.

[0036] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0037] In the embodiment of the present invention, basic parameters are determined through basic filling body tests, and numerical simulation methods are used to establish numerical models and medium mechanics models that conform to the actual situation on site, so as to analyze the evolution of stress, displacement and plastic zone around the stope under different key layer thicknesses and filling body strengths. Then, a combined weighted VIKOR comprehensive evaluation method is constructed, which organically combines safety indicators (maximum tensile stress, plastic zone, roof displacement) with economic indicators (cost per ton of ore). A comprehensive evaluation system is established to determine the optimal parameters that meet comprehensive requirements. The optimized filling body parameters can not only ensure the safety of the stope, but also effectively reduce the cost per ton of ore in mining. This overcomes the limitations of traditional single safety criteria and is more scientific and practical.

[0038] In the embodiment of the present invention, through orthogonal experimental design, combined with FLAC3D simulation analysis of the displacement, stress and plastic zone distribution of the mining area under different key layer thicknesses and filling body strengths, the influence trend of each factor on the stability of the filling false roof can be clearly determined, which provides a scientific basis for determining the optimal thickness and strength of the key layer of the filling false roof, and helps to find the optimal parameter combination that balances safety and economy. At the same time, SPSS software is used to perform range analysis and variance analysis to accurately quantify the degree of influence of each factor (common layer strength, key layer thickness, key layer strength) on the filling false roof stability-related indicators (roof displacement, plastic zone volume, maximum tensile stress, etc.) and the significance of the influence, so that designers can optimize key factors in a targeted manner and improve the reliability of the filling false roof stability design. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a stress-strain curve diagram of the test blocks filled with different ratios obtained in Example 1 of the present invention.

[0040] Figure 2 This is a schematic diagram of the stope model obtained in Example 3 of the present invention.

[0041] Figure 3 This is a schematic diagram of the steel mesh obtained in Example 3 of the present invention.

[0042] Figure 4 This is a partial simulation result diagram obtained in Example 3 of the present invention.

[0043] Figure 5 This is a visual diagram of the range analysis obtained in Example 3 of the present invention.

[0044] Figure 6 This is a comprehensive indicator system diagram obtained in Example 4 of the present invention. DETAILED DESCRIPTION

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0046] Most of the existing methods for determining the thickness or strength of the key layer of the filling false roof are based on theoretical models. However, due to the different mining technologies and complex hydrogeological characteristics of various mines, it is difficult to obtain a method for determining the key layer thickness and strength that is sufficient to meet the needs of the corresponding mines by relying on theoretical model calculations. To address the above problems, we propose a high-access filling false roof key layer determination method. When implementing the method, the basic mechanical parameters of the filling body are first obtained based on the basic mechanical properties test of the filling body, and then the filling false roof mechanical model is constructed based on the thick plate theory to obtain the analytical solution of the tensile stress component. The stability of the filling false roof is verified in combination with the safety factor. The influencing factors of the filling false roof stability are analyzed based on numerical simulation methods, and the significance level of the influence of the influencing factors on the stability of the filling false roof is determined. Finally, the combined weighted VIKOR comprehensive evaluation method is used to evaluate the influencing factors of the influencing factor set. The solution with the smallest decision index value is the optimal filling false roof solution, and the optimal filling false roof parameters are output to complete the determination of the key layer of the filling false roof. In the embodiment of the present invention, basic parameters are determined through basic filling body tests, and numerical simulation methods are used to establish numerical models and medium mechanics models that conform to the actual situation on site, so as to analyze the evolution of stress, displacement and plastic zone around the stope under different key layer thicknesses and filling body strengths. Then, a combined weighted VIKOR comprehensive evaluation method is constructed, which organically combines safety indicators (maximum tensile stress, plastic zone, roof displacement) with economic indicators (cost per ton of ore). A comprehensive evaluation system is established to determine the optimal parameters that meet comprehensive requirements. The optimized filling body parameters can not only ensure the safety of the stope, but also effectively reduce the cost per ton of ore in mining. This overcomes the limitations of traditional single safety criteria and is more scientific and practical.

[0047] An embodiment of the present invention provides a method for determining a key layer of a false ceiling for filling a high-access route. The method for determining a key layer of a false ceiling for filling a high-access route specifically includes:

[0048] S10, obtaining basic mechanical parameters of the filling body based on a basic mechanical property test of the filling body;

[0049] S20, load the basic mechanical parameters of the filling body, construct the filling false roof mechanical model based on the thick plate theory to obtain the analytical solution of the tensile stress component, verify the stability of the filling false roof in combination with the safety factor, and output the filling false roof stability analysis results;

[0050] S30, obtaining the results of the filling false roof stability analysis, analyzing the factors affecting the filling false roof stability based on numerical simulation, determining the significance level of the influence of the factors on the filling false roof stability, and obtaining a set of influencing factors including the degree of influence;

[0051] S40, loading the influencing factor set, pre-building the VIKOR comprehensive evaluation method based on combined weighting, using the VIKOR comprehensive evaluation method based on combined weighting to evaluate the influencing factors of the influencing factor set, taking the scheme with the smallest decision index value as the optimal scheme for filling the false roof, and outputting the optimal parameters for filling the false roof.

[0052] In the embodiment of the present invention, basic parameters are determined through basic filling body tests, and numerical simulation methods are used to establish numerical models and medium mechanics models that conform to the actual situation on site, so as to analyze the evolution of stress, displacement and plastic zone around the stope under different key layer thicknesses and filling body strengths. Then, a combined weighted VIKOR comprehensive evaluation method is constructed, which organically combines safety indicators (maximum tensile stress, plastic zone, roof displacement) with economic indicators (cost per ton of ore). A comprehensive evaluation system is established to determine the optimal parameters that meet comprehensive requirements. The optimized filling body parameters can not only ensure the safety of the stope, but also effectively reduce the cost per ton of ore in mining. This overcomes the limitations of traditional single safety criteria and is more scientific and practical.

[0053] Example 1

[0054] An embodiment of the present invention provides a method for obtaining basic mechanical parameters of a filling body based on a basic mechanical property test of the filling body. The method for obtaining basic mechanical parameters of a filling body based on a basic mechanical property test of the filling body specifically includes:

[0055] S101, determining the filling type and basic mechanical parameter type, wherein the filling includes cement, river sand, and waste rock, and the basic mechanical parameter types include density, tensile strength, internal friction angle, cohesion, elastic modulus, and Poisson's ratio, while the basic mechanical parameters are parameters of the ore body, surrounding rock, and key layers and common layers of the filling;

[0056] S102, conduct physical and chemical property tests on the filling material, including water content, specific gravity, loose / tight bulk density, porosity, and particle size distribution;

[0057] S103: Prepare filling slurry according to the proportion design test plan and the filling slurry proportion plan. Pour the prepared slurry into the test mold. After standing for 24 hours, remove the filling body sample and mark the group and date. Place the filling body sample in a standard curing box and cure to the corresponding age (3 days, 7 days, 28 days).

[0058] S104, perform uniaxial compression test and uniaxial tensile test on the filling body sample and record them. Use origin to draw stress-strain curve. Figure 1 The stress-strain curves of the filling test blocks with different proportions obtained in Example 1 of the present invention are shown. After dividing the elastic stages, linear fitting is performed, and the slope obtained is the elastic modulus of the filling body.

[0059] In the embodiments of the present invention, by obtaining basic mechanical parameters such as density, tensile strength, internal friction angle, cohesion, elastic modulus, Poisson's ratio, etc., reliable and effective data can be provided for subsequent research.

[0060] Example 2

[0061] An embodiment of the present invention provides a method for constructing a filling false roof mechanical model based on thick plate theory to obtain an analytical solution for a tensile stress component. The method for constructing a filling false roof mechanical model based on thick plate theory to obtain an analytical solution for a tensile stress component specifically includes:

[0062] S201, pre-constructing a filling false roof model, simplifying the filling false roof model into a four-side simply supported structure, and constructing a filling false roof mechanical model in combination with thick plate model theory;

[0063] S202, obtaining analytical solutions for the maximum tensile stress along the x-axis and y-axis directions through a filling false roof mechanical model;

[0064] S203, verifying the stability of the filling false roof through numerical simulation results, and outputting the filling false roof stability analysis results.

[0065] It should be noted that the method of constructing a filling false roof mechanical model based on thick plate model theory includes:

[0066] S2011, the infill false roof model is simplified to a four-sided simply supported structure with the following boundary conditions:

[0067]

[0068] Where: a is the span of the stope, m; b is the length of the stope, m; M x 、M y is the bending moment of the filling false top around the x-axis and y-axis; ψ x , ψ y is the rotation angle of the filling false top around the x-axis and y-axis;

[0069] S2012, according to Vlasov theory, the equilibrium differential equation is:

[0070]

[0071] Where: h is the thickness of the filling false roof, m; μ is the Poisson's ratio of the filling body; E is the elastic modulus of the filling body; D is the bending stiffness of the filling body, G is the shear deformation modulus of the filling body; Ф is

[0072] S2013, based on Mindlin theory, it can be seen that the filling false ceiling satisfies:

[0073]

[0074] Where: M xy is the moment of filling the false ceiling; Q x , Q y is the shear force along the x and y directions, m; τ x , τ y is the shear stress along the x-axis and y-axis;

[0075] S2014, assume that the deflection and rotation displacement functions are:

[0076]

[0077] S2015, for a thick plate with a false roof and simple support on four sides, the maximum bending moment occurs in the middle position, so when x = a / 2, y = b / 2, it has the maximum value:

[0078]

[0079] S2016, the maximum tensile stress occurs on the lower surface of the filling false roof, so the maximum tensile stress generated on the lower surface can be calculated according to the following formula:

[0080]

[0081] S2017, the maximum tensile stress along the x-axis and y-axis is:

[0082]

[0083] S201, in order to ensure the safety of actual mining operations at the mine site, the maximum tensile stress calculated based on the thick plate theoretical model is combined with a safety factor and the maximum tensile stress theory:

[0084] σ t =f×max(σ xmax ,σ ymax )

[0085] Where: σ t To meet the tensile strength of the filling false roof stability; f is the safety factor, generally taken as 1.5;

[0086] In the embodiments of the present invention, a mechanical model of a filling false ceiling based on thick plate theory can be used to analyze the stability of the filling false ceiling. This model can also be verified with the results of numerical simulations. If the assumptions are consistent, the constructed mechanical model of the filling false ceiling can be considered reliable.

[0087] Example 3

[0088] An embodiment of the present invention provides a method for analyzing factors affecting the stability of a filled false ceiling based on numerical simulation. The method for analyzing factors affecting the stability of a filled false ceiling based on numerical simulation specifically includes:

[0089] S301, design an orthogonal experiment plan based on mine requirements and construct an orthogonal experiment table;

[0090] It should be noted that when designing the orthogonal experimental scheme based on the needs of the mine, in the selection of influencing factors, the core parameters affecting the stability of the filling false roof are determined to be the key layer thickness, key layer strength, and ordinary layer strength. In terms of horizontal division, the value range and level of each parameter are set according to the basic mechanical parameters of the filling body obtained in the mine and Example 1 test. Among them, the key layer thicknesses are 1m, 2m, 3m, and 4m respectively, the key layer strengths are 4MPa, 5MPa, 6MPa, and 9MPa respectively, and the ordinary layer strengths are 2MPa, 2.5MPa, 3MPa, and 4MPa respectively.

[0091] S302, constructing a numerical model of the mine stope;

[0092] In the embodiment of the present invention, a numerical model of the stope was established based on the actual mine. This study set up 4 sections from top to bottom. The stope section specification is 6m×10m, the stope length is 50m, there are 10 odd-layer stopes, and 9 even-layer stopes. According to the Saint-Venant principle, the range of the entire stope numerical model is 3-5 times the range of the specific research ore body. A steel mesh is laid at the bottom of the stope. The grid of the stope numerical model adopts an encrypted division method in the specific research area. At the same time, the software involved in this embodiment includes but is not limited to Rhino, FLAC3D, and SPSS. Specifically, Figure 2 、 Figure 3 As shown. Among them, Figure 2 This is a schematic diagram of the stope model obtained in Example 3 of the present invention. Figure 3This is a schematic diagram of the steel mesh obtained in Example 3 of the present invention. At the same time, when constructing the numerical model of the stope, a medium mechanics model and failure criterion are set. In this embodiment, the test mining area is located within the range of the tectonic stress field, the stope is buried at a large depth, the horizontal ground stress is significant, and the ore rock joints and fissures are developed, showing a random distribution characteristic. The Mohr-Coulomb strength criterion and the tensile failure criterion correspond to the stope numerical model. From a holistic perspective, the ore rock mass and backfill in the test mining area can be considered isotropic, so the numerical model in this embodiment adopts the Mohr-Coulomb model.

[0093] S303, setting boundary conditions and initial stress field;

[0094] In this embodiment of the present invention, after the numerical model of the mine stope is constructed, it is necessary to set the material model parameters. The material model parameters are obtained based on the basic mechanical parameters of the filling body obtained in the experiment of Example 1. Table 1 shows the filling body parameter diagram obtained in Example 3 of the present invention. The boundary conditions of the model are set based on the basic mechanical parameters of the filling body. The initial stress is mainly composed of the rock mass deadweight stress and geological tectonic stress. Since the geological tectonic stress is very small in actual analysis, only the rock mass deadweight stress is considered in this embodiment. The deadweight stress field during simulation is as follows:

[0095] σ z =γH

[0096]

[0097] Where: σ x , σ y , σ z is the principal stress in the x, y, and z directions, MPa; γ is the bulk density of the rock mass; H is the burial depth of the ore body, m; μ is the Poisson's ratio;

[0098] Table 1

[0099]

[0100] During the model construction process, the numerical model of the stope was fixed on all sides and the bottom, and the top was set as a free boundary.

[0101] S304, using numerical simulation to analyze the excavation process, analyze the displacement distribution, maximum and minimum stress distribution, and plastic zone distribution, and obtain analysis results of the displacement distribution, maximum and minimum stress distribution, and plastic zone distribution;

[0102] S305, using SPSS software to perform variance analysis and range analysis on the analysis results, analyze the influence relationship of the influencing factors on the stability of the filling false roof, determine the significance level of the influence of the influencing factors on the stability of the filling false roof, and obtain an influencing factor set including the degree of influence.

[0103] In this embodiment, the results of displacement, maximum and minimum principal stresses, and plastic zone distribution are obtained through numerical simulation software. Figure 4 The following diagram shows some simulation results obtained in Example 3 of the present invention. The simulation results are analyzed and plotted into a table. Then, using the statistical analysis software SPSS, variance analysis is performed to quantify the significance level of the influence of each factor on the stability of the filling false ceiling. The influence of each factor on the stability of the filling false ceiling at different values ​​is further explored through the range. Figure 5 The figure shows the intuitive diagram of the range analysis obtained in Example 3 of the present invention.

[0104] In the embodiments of the present invention, the degree of influence of each influencing factor can be determined through range analysis. The R value can reflect the importance of each factor, and the larger the R value, the greater the influence of the factor on the target parameter. For the top plate displacement, plastic zone volume, and tensile stress of the filling body, the strength of the ordinary layer filling body has the greatest impact, with range values ​​of 1.45, 4.19, and 0.28, respectively; the influence of the critical layer thickness is second, with range values ​​of 0.53, 1.45, and 0.23, respectively; the influence of the critical layer strength is the smallest, but overall it is not much different from the critical layer thickness, with range values ​​of 0.52, 1.11, and 0.22, respectively.

[0105] The significance of each influencing factor can be determined through variance analysis. For the top displacement, plastic zone volume, and tensile stress of the filling body, the corresponding common layer strength had significance P values ​​of 0.000, 0.000, and 0.001, respectively, all less than 0.01, indicating that the common layer strength has a highly significant effect on the filling body's stability. Similarly, the significance P values ​​for the key layer thickness were all less than 0.05, indicating that it also has a significant effect on stability. The key layer strength for the plastic zone volume was greater than 0.05, indicating that strength had no significant effect in this regard, and its influence was slightly weaker than the other two factors. The results show that as the thickness of the key layer of the filling false roof increases, the filling body strength increases, the false roof's downward displacement, plastic zone, and tensile stress all decrease, and the filling false roof's stability is improved.

[0106] In the embodiment of the present invention, through orthogonal experimental design, combined with FLAC3D simulation analysis of the displacement, stress and plastic zone distribution of the mining area under different key layer thicknesses and filling body strengths, the influence trend of each factor on the stability of the filling false roof can be clearly determined, which provides a scientific basis for determining the optimal thickness and strength of the key layer of the filling false roof, and helps to find the optimal parameter combination that balances safety and economy. At the same time, SPSS software is used to perform range analysis and variance analysis to accurately quantify the degree of influence of each factor (common layer strength, key layer thickness, key layer strength) on the filling false roof stability-related indicators (roof displacement, plastic zone volume, maximum tensile stress, etc.) and the significance of the influence, so that designers can optimize key factors in a targeted manner and improve the reliability of the filling false roof stability design.

[0107] Example 4

[0108] An embodiment of the present invention provides a method for evaluating the influencing factors of an influencing factor set using a combined weighted VIKOR comprehensive evaluation method. The method for evaluating the influencing factors of an influencing factor set using a combined weighted VIKOR comprehensive evaluation method specifically includes:

[0109] S401, load the influencing factor set, decompose the decision problem based on the AHP method, subjectively weight the influencing factors, and obtain the subjective weights of the influencing factors;

[0110] It should be noted that the present invention constructs a combined weighted VIKOR comprehensive evaluation method. Traditionally, filling parameters are determined based on the obtained safety indicators, which ignores the influence of economic indicators and the obtained results are rather one-sided.

[0111] It should be noted that when decomposing a decision problem using the AHP method, the top layer is the goal layer, which is used to clarify the ultimate goal of the decision. The middle layer is the criterion layer, whose various criteria refine the goal from multiple dimensions. The bottom layer is the indicator layer, which is composed of specific, quantifiable indicators corresponding to the criteria in the criterion layer and provides a quantitative basis for decision analysis. A consistency test is used, and the comprehensive weight obtained after passing the test is the subjective weight.

[0112] S402, objectively weighting the influencing factors based on the CRITIC method to obtain the objective weights of the influencing factors;

[0113] The CRITIC method breaks down complex problems into three levels. This allows for the construction of a raw indicator relationship matrix. After dimensionlessly transforming each indicator, the relationship matrix is ​​normalized and subjected to a one-time test. The standard deviation reflects the degree of data dispersion and, as an indicator's variability, illustrates differences in values ​​across different contexts. A larger value is assigned a greater weight. The correlation coefficient measures the relationship between different indicators and, as an indicator of conflict, helps prevent over-concentration of weights. A larger value is assigned a smaller weight. The resulting weight is the objective weight.

[0114] S403, obtaining the subjective weight and objective weight of the influencing factors, and combining the subjective weight and the objective weight to obtain a combined weight;

[0115] Therefore, to scientifically assign weights to each evaluation indicator, we used a combination of the analytic hierarchy process (AHP) and the objective weighting method (CRITIC) to perform subjective and objective weighting operations. Specifically, AHP leverages the expertise and rich experience of experts in related fields through the expert scoring process, enabling the weight allocation to fully reflect the relative importance of each evaluation indicator from a professional perspective and retaining the experts' professional experience in weight allocation.

[0116] S404: Use the VIKOR method to convert the problem's indicators and solutions into a decision matrix. After normalization, perform combined weighting. After determining the positive and negative ideal solutions, calculate the distance to the optimal solution and the group utility value, individual regret value, and decision indicator value. The solution with the smallest decision indicator value is the optimal solution for filling the false top, and output the optimal parameters for filling the false top.

[0117] In this embodiment, when pre-constructing the VIKOR comprehensive evaluation method based on combined weighting, a comprehensive evaluation system is formulated based on safety indicators and economic indicators, hoping to increase economic benefits while ensuring safety. Among them, the selection of safety indicators is crucial. The safety indicators selected based on numerical simulation are maximum tensile stress, yield rate, and roof subsidence. Since the main object of investigation is the filling body parameters, the influence of technical indicators is ignored. The economic indicator is the cost per ton of ore, which only considers the cost of filling materials. Figure 6The diagram of the comprehensive index system obtained in Example 4 of the present invention is shown. When the VIKOR comprehensive evaluation method with combined weighting is used to evaluate the influencing factors of the influencing factor set, AHP and CRITIC are combined and weighted, and the multi-criteria compromise solution ranking method VIKOR is used to perform multi-objective decision analysis on the evaluation indicators with different weights, which is used to determine the best filling false roof scheme, and AHP and CRITIC are combined and weighted. This method combines the advantages of both, taking into account the professional judgment of experts and utilizing the objective information of the data, thereby further improving the scientific nature and reliability of the weighting results, and providing a more solid weight basis for subsequent evaluation work. The multi-criteria compromise solution ranking method (VIKOR) is used to perform multi-objective decision analysis on the evaluation indicators with different weights to determine the best filling false roof scheme.

[0118] The AHP method is used to decompose complex decision-making problems into different levels. Typically, these levels are broken down into the goal level, the criteria level, and the indicator level. The top level is the goal level, which defines the ultimate goal to be achieved; the middle level is the criteria level, whose criteria refine the goal from multiple dimensions; and the bottom level is the indicator level, which consists of specific, quantifiable indicators that correspond to the criteria in the criteria level and provide a quantitative basis for decision analysis.

[0119] When decomposing decision problems based on the AHP method, the specific steps are as follows:

[0120] S4011, using comparison matrix A to compare each element;

[0121] Among them, the comparison matrix A is expressed as:

[0122]

[0123] S4012, by normalizing the eigenvector W of the comparison matrix. Thus, the weight w of each element can be calculated. i , and find the maximum characteristic root λ max . After normalization, it represents the relative weight;

[0124]

[0125] The degree of consistency can be evaluated by calculating the consistency index CI and the consistency ratio CR.

[0126] If CR<0.1, it is considered acceptable, where RI is the random consistency index.

[0127]

[0128] By combining the weights of each level, the final subjective weight can be obtained.

[0129] In an embodiment of the present invention, the CRITIC objective weighting method is a method for determining the weights of criteria in multi-criteria decision-making. It is based on the interrelationship between criteria, takes into account the interaction and dependency between criteria, and determines the weights by calculating their correlation coefficients. In order to make up for the limitations that may be caused by simple subjective weighting, CRITIC is introduced. This method determines the weights by the correlation between data, thereby improving the objectivity of the allocation. The present invention uses safety (maximum compressive stress, maximum tensile stress, plastic zone, roof displacement) and economy (ton of ore cost) as comprehensive evaluation indicators, and adopts AHP method and CRITIC method to respectively perform subjective and objective combined weighting on the above indicators, and finally uses VIKOR method for comprehensive evaluation. This method is a relatively objective weight assignment method that can provide more reasonable and reliable decision support. The main calculation steps are as follows:

[0130] S4021, CRITIC method breaks down complex problems into three levels. The original indicator relationship matrix X can be constructed:

[0131]

[0132] S4022, after dimensionless processing of each indicator, normalize the relationship matrix; where:

[0133] The bigger the better:

[0134]

[0135] The smaller the better:

[0136]

[0137] Where x' ij is the standard value after dimensionless processing; maxx ij For indicator A j The maximum value; minx ij For indicator A j The minimum value of .

[0138] S4023, standard deviation reflects the degree of data dispersion. As an indicator of variability, it can explain the differences in values ​​under different situations. The larger the standard deviation, the greater the weight assigned. The correlation coefficient can measure the relationship between different indicators. As an indicator of conflict, it can avoid excessive weight concentration. The larger the standard deviation, the smaller the weight assigned.

[0139] Calculate the variability index:

[0140]

[0141] In the formula, m is the number of research subjects; is the mean of the j-th indicator;

[0142] Calculate the conflict index:

[0143]

[0144] Where r jk is the correlation coefficient of the evaluation index; R j is the conflict of the jth indicator.

[0145] S4. Calculate w j And normalized.

[0146]

[0147] Where w j is the weight of the jth indicator; w j '—The weight of the jth indicator after normalization.

[0148] By combining the weights of each level, the final objective weight can be obtained.

[0149] In the embodiment of the present invention, the VIKOR method first determines the positive and negative ideal solutions of each indicator based on the indicator attribute characteristics and data, and then calculates the closeness of the solutions to the indicator data to achieve a comprehensive decision on multiple attributes of the object to be evaluated. The specific steps are as follows:

[0150] S4031, convert each indicator and option in the decision problem into a decision matrix. The decision matrix is ​​a two-dimensional matrix, in which each row represents an option, each column represents an indicator, and the elements in the two-dimensional matrix represent the attributes of the indicator.

[0151]

[0152] S4032, using the standard 0-1 transformation to the decision index b of the decision matrix ij Perform normalization and use the comprehensive weights obtained by combined weighting to weight the decision indicators. After determining the positive and negative ideal solutions, calculate the distance to the optimal solution;

[0153] For the positive indicators put in:

[0154] r + =max(x),r - =min(x)

[0155] For the negative indicator placed:

[0156] r + =min(x),r - =max(x)

[0157] Calculate the optimal solution distance:

[0158]

[0159] S4033, use the following formula to calculate the group utility value S and individual regret value R respectively.

[0160]

[0161] R=max(s)

[0162] S4034, calculating the compromise decision index value Q using S and R;

[0163]

[0164] Where S + is the maximum value in S; S - is the minimum value in S; v is the decision mechanism coefficient, which is generally 0.5.

[0165] In step S4035, the resulting comprehensive weights were assigned to each indicator, and then all options were ranked using the VIKOR method. See Table 2 for details. When using option 5, the decision indicator value reached the minimum, indicating that this structural parameter is the optimal parameter for the false roof, balancing both economy and safety.

[0166] Table 2

[0167]

[0168] In the embodiment of the present invention, the method for determining the key layer of the filling false roof of the high approach combines the parameters obtained by basic experiments, the rules of numerical simulation analysis and the optimal scheme of comprehensive evaluation. The process is clear, scientific and reasonable, and can be applied to the mining scenarios of broken ore bodies in different mines. It provides general technical ideas and method guidance for mining enterprises to formulate reasonable filling false roof design parameters, and has broad promotion and application value.

[0169] In summary, the present invention provides a method for determining the key layer of a high-access filling false roof. In the embodiment of the present invention, basic parameters are determined through basic filling body tests, and numerical simulation methods are used to establish a numerical model and a medium mechanics model that conforms to the actual situation on site, so as to analyze the evolution of stress, displacement and plastic zone around the mining site under different key layer thicknesses and filling body strengths. Then, a combined weighted VIKOR comprehensive evaluation method is constructed, which organically combines safety indicators (maximum tensile stress, plastic zone, roof displacement) with economic indicators (cost per ton of ore), and establishes a comprehensive evaluation system to determine the best parameters that meet comprehensive needs, so that the optimization results of the filling body parameters can not only ensure the safety of the mining site, but also effectively reduce the cost per ton of ore in mining, overcoming the limitations of traditional single safety criteria and being more scientific and practical.

[0170] It should be noted that for the aforementioned embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, because according to the present invention, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0171] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also fall within the scope of protection of the present invention.

Claims

1. A method for determining the key layer of a high-pass filling false roof, characterized in that: The method comprises: S10, obtaining basic mechanical parameters of the filling body based on a basic mechanical property test of the filling body; S20, load the basic mechanical parameters of the filling body, construct the filling false roof mechanical model based on the thick plate theory to obtain the analytical solution of the tensile stress component, verify the stability of the filling false roof in combination with the safety factor, and output the filling false roof stability analysis results; S30, obtaining the results of the filling false roof stability analysis, analyzing the factors affecting the filling false roof stability based on numerical simulation, determining the significance level of the influence of the factors on the filling false roof stability, and obtaining a set of influencing factors including the degree of influence; S40, loading the influencing factor set, pre-building the VIKOR comprehensive evaluation method based on combined weighting, using the VIKOR comprehensive evaluation method based on combined weighting to evaluate the influencing factors of the influencing factor set, taking the scheme with the smallest decision index value as the optimal scheme for filling the false roof, and outputting the optimal parameters for filling the false roof.

2. The method for determining the key layer of the false roof of a high-access route according to claim 1, characterized in that: The method for obtaining basic mechanical parameters of a filling body based on a basic mechanical property test of the filling body comprises: S101, determining the filling type and foundation mechanical parameter type, wherein the filling type includes cement, river sand, and waste rock, and the foundation mechanical parameter type includes density, tensile strength, internal friction angle, cohesion, elastic modulus, and Poisson's ratio; S102, conduct physical and chemical property tests on the filling material, including water content, specific gravity, loose / tight bulk density, porosity, and particle size distribution; S103, preparing a filling slurry based on the filling slurry ratio scheme, injecting the prepared slurry into a test mold, letting it stand for 24 hours, taking out the filling body sample and marking it with the group and date, placing the filling body sample in a standard curing box, and curing it to the corresponding age; S104: Perform uniaxial compression and uniaxial tensile tests on the filling sample, use Origin to draw a stress-strain curve, divide it into elastic stages, and perform linear fitting. The obtained slope is the elastic modulus of the filling.

3. The method for determining the key layer of the false roof of a high-access road according to claim 1, characterized in that: The method for constructing a filling false roof mechanical model based on thick plate theory to obtain an analytical solution for the tensile stress component includes: S201, pre-constructing a filling false roof model, simplifying the filling false roof model into a four-side simply supported structure, and constructing a filling false roof mechanical model in combination with thick plate model theory; S202, obtaining analytical solutions for the maximum tensile stress along the x-axis and y-axis directions through a filling false roof mechanical model; S203, verifying the stability of the filling false roof through numerical simulation results, and outputting the filling false roof stability analysis results.

4. The method for determining the key layer of the false roof of a high-access route according to claim 3, characterized in that: The method for analyzing factors affecting the stability of a filling false roof based on numerical simulation means includes: S301, design an orthogonal experiment plan based on mine requirements and construct an orthogonal experiment table; S302, constructing a numerical model of the mine stope; S303, setting boundary conditions and initial stress field; S304, using numerical simulation to analyze the excavation process, analyze the displacement distribution, maximum and minimum stress distribution, and plastic zone distribution, and obtain analysis results of the displacement distribution, maximum and minimum stress distribution, and plastic zone distribution; S305, using SPSS software to perform variance analysis and range analysis on the analysis results, analyze the influence relationship of the influencing factors on the stability of the filling false roof, determine the significance level of the influence of the influencing factors on the stability of the filling false roof, and obtain an influencing factor set including the degree of influence.

5. The method for determining the key layer of the false roof of a high-access route according to claim 1, wherein: The method for evaluating the influencing factors of the influencing factor set using the combined weighted VIKOR comprehensive evaluation method includes: S401, load the influencing factor set, decompose the decision problem based on the AHP method, subjectively weight the influencing factors, and obtain the subjective weights of the influencing factors; S402, objectively weighting the influencing factors based on the CRITIC method to obtain the objective weights of the influencing factors; S403, obtaining the subjective weight and objective weight of the influencing factors, and combining the subjective weight and the objective weight to obtain a combined weight; S404: Use the VIKOR method to convert the problem's indicators and solutions into a decision matrix. After normalization, perform combined weighting. After determining the positive and negative ideal solutions, calculate the distance to the optimal solution and the group utility value, individual regret value, and decision indicator value. The solution with the smallest decision indicator value is the optimal solution for filling the false top, and output the optimal parameters for filling the false top.

6. The method for determining the key layer of the false roof of a high-access route according to claim 5, characterized in that: When the combined weighted VIKOR comprehensive evaluation method is used to evaluate the influencing factors of the influencing factor set, AHP and CRITIC are combined to assign weights, and the multi-criteria compromise solution ranking method VIKOR is used to perform multi-objective decision analysis on the evaluation indicators with different weights to determine the optimal filling false roof scheme.

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