Sensitivity analysis method and system for influence factors of moisture redistribution of aeration zone in subsidence area

Abstract

The invention discloses a sensitivity analysis method and system for influence factors of moisture redistribution of an aeration zone in a subsidence area, and relates to the technical field of protection and utilization of water resources in ecologically fragile mining areas in northwest. The method comprises the following steps: carrying out a soil-water characteristic curve test under a disturbance stress path in a coal mining collapse subsidence area; a VG soil-water characteristic curve model suitable for the coal mining collapse subsidence area is obtained; determining the moisture redistribution condition of the vadose zone of the settlement area under coal mining collapse disturbance under each working condition, wherein the moisture redistribution condition is represented by saturation; based on a range analysis method and a multiple linear regression analysis method, sensitivity analysis is carried out on all main influence factors influencing moisture redistribution of the aeration zone of the subsidence zone under coal mining collapse disturbance, and sensitivity of all the main influence factors is ranked. According to the method, the accurate water redistribution rule of the aeration zone in the coal mining collapse subsidence area can be obtained through calculation, the sensitivity of the influence factors of the water redistribution of the aeration zone is reasonably analyzed, and an important theoretical basis is provided for rapid repair of the coal mining collapse subsidence area.

Description

Technical Field

[0001] The present invention relates to the technical field of water resource protection and utilization in ecologically fragile mining areas in the northwest, and particularly relates to a method and system for sensitivity analysis of influencing factors for water redistribution in the vadose zone of a subsidence area. Background Technique

[0002] The statements in this part merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] The ecological geological environment in the arid and semi-arid regions of the northwest is fragile and water resources are scarce. As the only moisture transmission medium for surface water - groundwater - vegetation water use in arid and semi-arid regions, the moisture dynamics in the vadose zone directly control the ecological carrying capacity. Large-scale coal resource mining causes surface subsidence, forming coal mining subsidence fracture zones and subsidence areas, both of which will lead to water redistribution in the vadose zone, thus easily inducing ecological and geological environment problems such as vegetation withering, desertification, and decline of the phreatic water level. Among them, the subsidence area accounts for about 65% - 85% of the total area of the entire coal mining subsidence area (the sum of the fracture zone and the subsidence area). How to accurately determine the main influencing factors for water redistribution in the vadose zone of the subsidence area under coal mining disturbance has become a key issue for subsequent ecological reconstruction in the coal mining subsidence area. It has important scientific research significance and application value for revealing the competition mechanism between preferential flow and matrix flow in the vadose zone fissures, the degradation threshold of soil physical properties, and further guiding the optimization of mine ecological restoration technology, warning the risk of secondary disasters in the mining area, and improving the comprehensive utilization efficiency of water resources.

[0004] The water redistribution in the vadose zone of the subsidence area under coal mining subsidence disturbance is affected by multiple factors. It is very difficult to consider the influence of all factors in the subsequent simulation process of vadose zone water recovery. Therefore, it is necessary to screen out the main factors affecting the water redistribution in the vadose zone of the subsidence area under coal mining subsidence disturbance. The main factors affecting the water redistribution in the vadose zone of the subsidence area under coal mining subsidence disturbance are different in different mining areas, and there is no unified consensus for the time being. Based on this, it is difficult to study the water redistribution in the vadose zone of the subsidence area under coal mining subsidence disturbance. Often, the water redistribution situation in the vadose zone of the subsidence area under coal mining subsidence disturbance obtained from theoretical research does not match the actual situation, and it cannot guide the ecological and geological environmental protection and green mine construction in the mining area. Currently, the analytic hierarchy process is mostly used to analyze the water redistribution situation in the vadose zone of the subsidence area under coal mining subsidence disturbance based on field monitoring data. Although the above research has achieved relatively rich research results and obtained the main factors affecting the water redistribution in the vadose zone of the subsidence area under coal mining subsidence disturbance to a certain extent, there are still the following deficiencies: (1) The on-site monitoring of the water in the vadose zone of the coal mining subsidence area takes a long time, has a large workload and high cost, but the data volume is small, and it is impossible to study the water redistribution situation in the vadose zone of the coal mining subsidence area under the influence of multiple factors at the same time; (2) Existing sensitivity analyses of factors affecting the redistribution of moisture in the vadose zone of a subsidence area caused by coal mining subsidence often fail to take into account the randomness of cracks and fail to adopt a VG model suitable for specific mining areas. In addition, the current analytic hierarchy process has shortcomings such as strong subjectivity and poor rationality of weight analysis. Therefore, the sensitivity and weights of the main factors affecting the redistribution of moisture in the vadose zone of a subsidence area caused by coal mining subsidence are often not accurate enough.

[0005] In summary, how to achieve objective and reasonable sensitivity analysis of various influencing factors of water redistribution in the aeration zone of the subsidence area under coal mining subsidence disturbance, make it suitable for the VG model, and provide a theoretical basis for guiding the ecological and geological environment protection and green mine construction in mining areas has become a technical problem that needs to be urgently solved in existing technologies. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a sensitivity analysis method and system for factors affecting moisture redistribution in the vadose zone of a subsidence area, which can calculate the accurate law of moisture redistribution in the vadose zone of a subsidence area caused by coal mining, and reasonably analyze the sensitivity of factors affecting moisture redistribution in the vadose zone of a subsidence area caused by coal mining subsidence, thereby providing an important theoretical basis for the rapid repair of a subsidence area caused by coal mining.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions: A first aspect of the present invention provides a sensitivity analysis method for factors affecting water redistribution in aeration zones of a settlement area, comprising the following steps: Conduct soil-water characteristic curve tests under disturbance stress paths in coal mining subsidence areas; Obtain the VG soil-water characteristic curve model applicable to the coal mining subsidence area; Determine the redistribution of water in the aeration zone of the subsidence area under the disturbance of coal mining subsidence under various working conditions characterized by saturation; Based on the range analysis method and multivariate linear regression analysis method, a sensitivity analysis was conducted on the main influencing factors affecting the redistribution of moisture in the aeration zone of the subsidence area caused by coal mining subsidence, and the sensitivity of each main influencing factor was ranked.

[0008] Furthermore, the specific steps for conducting soil-water characteristic curve tests under the disturbance stress path in coal mining subsidence settlement areas are as follows: Determine the boundary range of coal mining subsidence area based on probability integral method; Carry out in-situ random sampling of the coal mining subsidence area according to the determined boundary range; Determine the disturbance stress path in coal mining subsidence settlement areas; Based on random sampling, soil-water characteristic curve test under disturbance stress path in coal mining subsidence settlement area was carried out.

[0009] Furthermore, the specific steps for determining the disturbed stress path in the coal mining subsidence area are as follows: Based on the measured values of the collapse movement and deformation of the mined soil mass, combined with elastoplastic theory analysis, the principal stress distribution in the coal mining subsidence area is determined to obtain the disturbed stress path in the coal mining subsidence area. During the process of obtaining the disturbed stress path in the coal mining subsidence area, the stress states pass through in sequence: triaxial equal pressure to the original horizontal stress state, continue to increase the axial pressure to the in-situ stress state, increase the confining pressure until the specimen is about to fail, and unload the confining pressure in stages until creep to the original stress state.

[0010] Further, the specific steps for determining the moisture redistribution in the vadose zone of the coal mining subsidence area under different working conditions characterized by saturation are as follows: Based on the VG soil-water characteristic curve model, the main influencing factors and their value ranges affecting the moisture redistribution in the vadose zone of the coal mining subsidence area are determined, and an orthogonal experiment design is carried out; Write the random crack code based on the orthogonal experiment conditions; Import the random crack code and the VG model into COMSOL, and input the values of the main influencing factors under each working condition into COMSOL for numerical simulation; By arranging multiple monitoring lines in the numerical simulation to obtain the saturation of the monitoring lines, and taking the average saturation of each monitoring line as the saturation at the current depth, the moisture redistribution in the vadose zone of the coal mining subsidence area under different working conditions is determined.

[0011] Furthermore, due to the interaction of the mining area's stratigraphic structure, hydrogeological conditions, and mining conditions, the soil type, porosity, fracture number, permeability coefficient of the vadose zone, fracture permeability coefficient, and coal seam thickness in the mined-out area are selected as the main influencing factors for the moisture redistribution in the vadose zone of the coal mining subsidence area.

[0012] Furthermore, the specific steps for performing sensitivity analysis on the main influencing factors affecting the moisture redistribution in the vadose zone of the coal mining subsidence area based on the range analysis method and the multiple linear regression analysis method are as follows: Conduct multiple linear analysis on the average saturation of the representative monitoring lines and the values of the main influencing factors under each working condition; Conduct range analysis on the average saturation of the representative monitoring lines and the values of the main influencing factors under each working condition; Comprehensively consider the results of the range analysis method and the multiple linear regression analysis method for the sensitivity analysis results of the main influencing factors affecting the moisture redistribution in the vadose zone under coal mining disturbance, and finally obtain the sensitivity ranking of the main influencing factors.

[0013] Further, based on the sensitivity analysis results of the main factors, the AHP method based on multiple linear regression and range analysis is used to determine the weights of the main influencing factors, and the sensitivity analysis ranking of the main influencing factors is verified.

[0014] The second aspect of the present invention provides a sensitivity analysis system for the influencing factors of water redistribution in the vadose zone of the subsidence area, including: An experimental module configured to carry out soil-water characteristic curve tests under the disturbed stress path in the coal mining subsidence area. A model construction module configured to obtain a VG soil-water characteristic curve model applicable to the coal mining subsidence area. A distribution situation determination module configured to determine the water redistribution situation in the vadose zone of the subsidence area under coal mining subsidence disturbance characterized by saturation. An influencing factor sensitivity analysis module configured to perform sensitivity analysis on the main influencing factors affecting the water redistribution in the vadose zone of the subsidence area under coal mining subsidence disturbance based on the range analysis method and the multiple linear regression analysis method, and rank the sensitivities of the main influencing factors.

[0015] The third aspect of the present invention provides a medium on which a program is stored, and when the program is executed by a processor, it implements the steps in the sensitivity analysis method for the influencing factors of water redistribution in the vadose zone of the subsidence area as described in the first aspect of the present invention.

[0016] The fourth aspect of the present invention provides a device, including a memory, a processor, and a program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps in the sensitivity analysis method for the influencing factors of water redistribution in the vadose zone of the subsidence area as described in the first aspect of the present invention.

[0017] The above one or more technical solutions have the following beneficial effects: The present invention discloses a sensitivity analysis method and system for the influencing factors of water redistribution in the vadose zone of the subsidence area, which overcomes the disadvantages of long field monitoring time, large workload, high cost, small data volume, and inability to study the water redistribution situation in the vadose zone of the coal mining subsidence area under the influence of multiple factors at the same time. By considering the randomness of fractures in numerical simulation and adopting the VG model applicable to specific mining areas, and using the AHP hierarchical analysis method based on multiple linear analysis and range analysis, the deficiencies of too strong subjectivity and poor rationality of weight analysis can be overcome, and the main factors affecting the water redistribution in the vadose zone of the subsidence area under coal mining subsidence disturbance, their sensitivity strengths and weights can be accurately determined.

[0018] The advantages of the additional aspects of the present invention will be partially given in the following description, partially will become obvious from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The attached drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments of the invention and their descriptions are used to explain the invention and do not unduly limit the invention.

[0020] Figure 1 It is a flow chart of the sensitivity analysis method for influencing factors of moisture redistribution in the vadose zone of the subsidence area in the first embodiment of the present invention; Figure 2 It is a schematic diagram of the coal mining subsidence area and the coal mining collapse crack area involved in the first embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof; Embodiment 1: The first embodiment of the present invention provides a sensitivity analysis method for influencing factors of moisture redistribution in the vadose zone of the subsidence area, as Figure 1As shown in the figure, it includes the following steps: First, comprehensively determine the boundary range of the coal mining subsidence area based on the probability integral method and the Code for Prevention and Control of Coal Mining Subsidence (GB 51023-2014), and then conduct in-situ random sampling in the coal mining subsidence area; determine the disturbed stress path in the coal mining subsidence area, carry out the soil-water characteristic curve test under the disturbed stress path in the coal mining subsidence area, and obtain the VG soil-water characteristic curve model applicable to this coal mining subsidence area; at the same time, determine the main factors and their value ranges affecting the moisture redistribution in the vadose zone of the coal mining subsidence area. Based on this, carry out orthogonal experimental design; write random crack code based on MATLAB, import the random crack code and the VG model into COMSOL, and determine the moisture redistribution in the vadose zone of the coal mining subsidence area characterized by saturation based on COMSOL numerical simulation; and conduct sensitivity analysis on the main factors affecting the moisture redistribution in the vadose zone of the coal mining subsidence area based on the range analysis method and the multiple linear regression analysis method; determine the sensitivity ranking of the main factors affecting the moisture redistribution in the vadose zone of the coal mining subsidence area, and combine the sensitivity analysis results to determine the weights of each main factor by using the analytic hierarchy process AHP method based on multiple linear regression and range analysis. This embodiment has important scientific research significance and application value for studying the moisture redistribution law in the vadose zone of the coal mining subsidence area, accurately determining the sensitivity of the influencing factors of moisture redistribution in the vadose zone of the coal mining subsidence area, and realizing the rapid repair of the coal mining subsidence area.

[0023] Specifically, it includes the following steps: Step 1: Carry out the soil-water characteristic curve test under the disturbed stress path in the coal mining subsidence area.

[0024] Step 1.1: Determine the boundary range of the coal mining subsidence area based on the probability integral method.

[0025] Step 1.1.1: Establish a probability integral model for determining the boundary range of the coal mining area.

[0026] Take a certain unit i mined in the inclined coal seam. According to the basic principle of the probability integral method, the final subsidence value of any point (x, y) on the ground caused by the mining of the unit is: (1).

[0027] Among them, is the final subsidence value of any point (x, y) on the ground, r is the main influence radius, ; H 0 is the average mining depth; β is the main influence angle; , i is the number of the mined unit, H 1 is the plane coordinate (x i , y i) The vertical distance, θ is the maximum subsidence angle; (x i , y i ) are the plane coordinates of the center point of the i-th unit; (x, y) are the coordinates of any point on the ground surface.

[0028] Step 1.1.2: Based on the actual observation experience parameters accumulated in long-term similar mining areas and combined with the actual coal mining, determine the parameter values in the probability integral model that affect the boundary range of the coal mining subsidence area.

[0029] Step 1.1.3: Based on the probability integral model, determine the boundary range of the coal mining subsidence area. Combining with the settlement boundary demarcation standard in the "Code for Prevention and Control of Coal Mining Subsidence" (GB 51023-2014), determine the coal mining settlement area and the coal mining crack area, as Figure 2 shown.

[0030] Step 1.2: Conduct in-situ random sampling in the coal mining settlement area according to the determined boundary range.

[0031] In this embodiment, after determining the boundary range, in-situ random sampling is carried out in the coal mining subsidence settlement area, and a total of 3 random sampling points are selected.

[0032] Step 1.3: Determine the disturbed stress path in the coal mining subsidence settlement area.

[0033] In this embodiment, based on the measured values of the collapse movement and deformation of the mining soil mass, combined with the elastic-plastic theory, analyze the principal stress distribution in the coal mining subsidence settlement area, and determine the disturbed stress path in the coal mining subsidence settlement area. Among them, the stress states in the process of obtaining the disturbed stress path in the coal mining subsidence settlement area successively pass through: triaxial equal pressure to the original horizontal stress state, continue to increase the axial pressure to the in-situ rock stress state, increase the confining pressure until the specimen is about to fail, and unload the confining pressure in stages until creep to the original stress state.

[0034] Step 1.4: Carry out the soil-water characteristic curve test under the disturbed stress path in the coal mining subsidence settlement area based on random sampling.

[0035] Step 1.4.1: After preparing the specimen according to the instrument size and saturating the specimen, carry out the dehumidification process of the specimen under the disturbed stress path in the coal mining subsidence settlement area until the residual moisture content of the specimen is reached.

[0036] Step 1.4.2: Record the moisture content data at each matrix suction.

[0037] Step 2: Obtain the VG soil-water characteristic curve model applicable to this coal mining subsidence settlement area.

[0038] Specifically, based on the water content data at each matrix suction recorded during the test of the soil-water characteristic curve under the disturbed stress path in the coal mining subsidence area, the VG soil-water characteristic curve model applicable to this coal mining subsidence area is fitted through the Origin data processing software.

[0039] The VG (Van Genuchten) model is one of the most commonly used models in the soil water characteristic curve. It describes the functional relationship between soil matrix suction and volumetric water content through a mathematical equation and is widely used in research fields such as soil water movement, soil salinization, and slope stability.

[0040] Step 3: Determine the moisture redistribution in the vadose zone of the subsidence area under the disturbance of coal mining subsidence characterized by saturation.

[0041] Step 3.1: Based on the VG soil-water characteristic curve model, determine the main influencing factors and their value ranges that affect the moisture redistribution in the vadose zone of the subsidence area under the disturbance of coal mining subsidence, and carry out orthogonal experimental design.

[0042] Step 3.1.1: The influencing factors of moisture redistribution in the vadose zone of the subsidence area under the disturbance of coal mining subsidence are relatively complex. Due to the interaction of the mining area's stratigraphic structure, hydrogeological conditions, and mining conditions, it is determined to select the soil type of the vadose zone, porosity, fracture number, permeability coefficient of the vadose zone, fracture permeability coefficient, and coal seam mining thickness as the main influencing factors of moisture redistribution in the vadose zone of the subsidence area under the disturbance of coal mining subsidence.

[0043] Based on on-site measurements, numerical simulations, laboratory tests and other data, determine the value ranges of each main influencing factor, and let the value ranges of each factor be arranged according to 、 、 、 where \(i = 1, 2, 3, 4, 5, 6\); represents the minimum value in the value range of a certain factor; represents the maximum value in the value range of a certain factor.

[0044] Step 3.1.2: Select an orthogonal array according to the determined main influencing factors.

[0045] Orthogonal experiment is a scientific experimental design method based on orthogonal arrays. Its purpose is to efficiently analyze the influence of multiple factors on the results through a small number of representative experiments and find the optimal combination. It has the characteristics of high efficiency, balance, and analyzability. It can evenly match the levels of various factors while significantly reducing the number of experiments, avoid data bias, and can distinguish main effects and interaction effects to identify key factors. The main tool for orthogonal experimental design is the orthogonal array. Experimenters can search for the corresponding orthogonal array according to specific requirements such as the number of experimental influencing factors, the number of levels to be considered under each factor, and whether there are coupling relationships. Based on its orthogonality, select some representative points from the comprehensive experiment for orthogonal experiments, which can achieve the maximum amount of experimental results with the least number of experiments.

[0046] In orthogonal experiments, the index is the result variable that needs to be measured or optimized. It is used to evaluate the effects of different factor combinations, directly reflects the objectives of orthogonal experiments, and is the basis for judging the magnitude of factor influence. The independent variables that may affect the index in the experiment, that is, the controllable conditions or parameters to be studied, are called factors. And the level is the specific value or state set for each factor in the experiment, used to explore the influence law of this factor on the index. The orthogonal array is represented by L N ( p q ), where: L is the code of the orthogonal array; N is the total number of experiments; p is the number of levels of the factor; q is the number of columns of the orthogonal array, that is, the maximum number of factors that can be arranged.

[0047] In this embodiment, based on the main influencing factors and value ranges of the water redistribution in the vadose zone of the subsidence area disturbed by coal mining subsidence, orthogonal experiments are carried out. Specifically, according to the design principle of the orthogonal array, an orthogonal array of six factors and four levels L 32 (4 6 )is selected, that is, a total of 32 working conditions.

[0048] Step 3.2: Write random fracture codes using MATLAB based on the orthogonal experimental conditions.

[0049] In a specific implementation, write random fracture codes using MATLAB, which can achieve random fractures with a specified number, random positions, and given range lengths: % ---------- Parameter settings ---------- numfractures = 100; % Number of fractures domainSize = [0, 1000, 0, 1600]; % Area range [xmin, xmax, ymin, ymax] minLength = 20; % Minimum fracture length maxLength = 180; % Maximum fracture length % ---------- Initialize the figure window ---------- figure; hold on; axis equal; % Keep the aspect ratio of the horizontal and vertical axes the same axis([0 1000 0 1600]); % Force the display of the full area range grid on; % Display grid lines title('Fracture distribution map (X:0 - 1000, Y:0 - 1600)'); xlabel('X-axis'); ylabel('Y-axis'); % ---------- Generate and plot fractures ---------- fractures = zeros(numfractures, 4); % Pre-allocate a matrix to store fracture coordinates for i = 1:numfractures % Randomly generate the starting point (within domainSize) x1 = domainSize(1) + (domainSize(2)-domainSize(1)) * rand; y1 = domainSize(3) + (domainSize(4)-domainSize(3)) * rand; % Randomly generate the direction and length angle = 2 * pi * rand; % Random angle [0, 2π] length = minLength + (maxLength-minLength)*rand; % Random length % Calculate the end point x2 = x1 + length * cos(angle); y2 = y1 + length * sin(angle); % Ensure the end point does not exceed the region boundary x2 = max(min(x2, domainSize(2)), domainSize(1)); % X-axis constraint y2 = max(min(y2, domainSize(4)), domainSize(3)); % Y-axis constraint % Save the fracture coordinates to a matrix fractures(i, :) = [x1, y1, x2, y2]; % Plot the current fracture (red line + circle markers at endpoints) plot([x1, x2], [y1, y2], 'r', 'LineWidth', 1.5, 'MarkerSize', 4); end hold off。

[0050] Step 3.3: Import the random fracture code and VG model into COMSOL, and input the values of the main influencing factors under each working condition into COMSOL for numerical simulation.

[0051] Step 3.4: Obtain the saturation of the monitoring lines by arranging multiple monitoring lines in the numerical simulation, and take the average saturation of each monitoring line as the saturation at the current depth, so as to determine the moisture redistribution in the vadose zone of the subsidence area disturbed by coal mining subsidence under each working condition.

[0052] Moisture saturation refers to the ratio of the volume of water in the soil to the total pore volume, and is usually used to describe the relative saturation state of water in the soil. The saturation at different depths is different, and the saturation at the same depth is also different due to the influence of structures such as fractures and pores, permeability coefficients, etc. Therefore, in this embodiment, saturation is used to measure the relative moisture content.

[0053] Step 4: Conduct a sensitivity analysis on each of the main influencing factors affecting the moisture redistribution in the vadose zone of the subsidence area disturbed by coal mining subsidence based on the range analysis method and the multiple linear regression analysis method, and rank the sensitivities of each main influencing factor.

[0054] Step 4.1: Conduct a sensitivity analysis on each of the main influencing factors affecting the moisture redistribution in the vadose zone of the subsidence area disturbed by coal mining subsidence based on the range analysis method and the multiple linear regression analysis method.

[0055] Step 4.1.1: Conduct a multiple linear analysis on the average saturation of the representative monitoring lines and the values of the main influencing factors under each working condition.

[0056] In a specific implementation manner, a multiple linear analysis is conducted on the average saturation of the representative monitoring lines and the values of the main influencing factors under each working condition, and its regression equation is: (2)。

[0057] In the formula, β 0 , β 1 , β 2 ... β 6 are constants and correlation coefficients respectively, Y is the average saturation of the representative monitoring lines under various working conditions, and the values of the main influencing factors are X 1 , X 2 , X 3 ... X 6 ; the greater the correlation coefficient before each main influencing factor, the greater the impact of the change in the level of this factor on the test index, that is, the greater the sensitivity of this factor. In this embodiment, sensitivity refers to the degree of influence of the main influencing factors. The greater the sensitivity of the main influencing factors, the greater the impact of the change in the level of this factor on the test index, that is, the greater the influence of the water redistribution in the vadose zone of the coal mining subsidence area by this factor.

[0058] It should be particularly noted that generally, since the COMSOL numerical simulation software has a built-in function for arranging monitoring lines, theoretically, an infinite number of monitoring lines can be arranged, and the representativeness of the monitoring lines is judged according to the specific geographical conditions. Therefore, when performing range analysis and multiple linear analysis on the same area, the same batch of monitoring lines is used. For example, from the perspective of the water distribution in the vadose zone of the mining area in the arid and semi-arid regions of northwest China, monitoring lines are generally arranged at positions 6.2 m, 7 m, and 7.8 m from the surface along the x-direction, and a monitoring line is arranged along the y-direction in the middle of the model width. The above monitoring lines are used as the representative monitoring lines for the water distribution in the vadose zone of the mining area in the arid and semi-arid regions of northwest China.

[0059] Step 4.1.2: Conduct range analysis on the average saturation of the representative monitoring lines and the values of the main influencing factors under various working conditions.

[0060] In a specific implementation manner, range analysis is conducted on the average saturation of the representative monitoring lines and the values of the main influencing factors under various working conditions. The range value R j is the evaluation criterion for analyzing the factor sensitivity by the range method of each main influencing factor, and it is the difference between the maximum and minimum values of the average saturation E ij of the representative monitoring lines at each level of this factor. The calculation formula is: (3).

[0061] In the formula, E mj is the average value of each test result of factor j at level m, where m = 1, 2, 3, 4; j = 1, 2, 3, 4, 5, 6.

[0062] The greater the range R j , the greater the impact of the change in the level of this factor on the test index, that is, the greater the sensitivity of this factor; on the contrary, the range Rj The smaller it is, the less sensitive the factor is; Step 4.1.3: Comprehensively consider the sensitivity analysis results of each main influencing factor affecting the redistribution of vadose zone moisture under coal mining subsidence disturbance based on the results of the range analysis method and the multiple linear regression analysis method, and finally obtain the sensitivity ranking of each main influencing factor.

[0063] In this embodiment, using the range analysis method, a sensitivity analysis ranking will be obtained for one monitoring line. Similarly, using the multiple linear regression analysis method, a sensitivity analysis ranking will be obtained for one monitoring line. The average value of the accumulated rankings of each influencing factor is statistically calculated for comprehensive ranking.

[0064] For example: A total of four representative monitoring lines are taken. Assuming that the accumulated ranking of the number of fissures by the range analysis method is 1 + 2 + 1 = 4, and the accumulated ranking of the number of fissures by the multiple linear regression analysis method is 2 + 2 + 2 = 6, and its average value is (6 + 4) / 6 = 3.333. This is used as the ranking value of each influencing factor, and a comprehensive ranking is performed according to each ranking value to obtain the sensitivity analysis results of each main influencing factor for the redistribution of vadose zone moisture under coal mining subsidence disturbance. After obtaining the sensitivity ranking, artificial intervention can act on the top several sensitive factors that affect the redistribution of vadose zone moisture to promote the ecological restoration and land reclamation of the coal mining subsidence area.

[0065] Step 4.2: Based on the sensitivity analysis results of each main factor, use the analytic hierarchy process AHP method based on multiple linear regression and range analysis to determine the weights of each main influencing factor, and verify the sensitivity analysis ranking of each main influencing factor. Specifically, the magnitude of the calculated weight can verify the sensitivity ranking, and the two have a mutual verification relationship.

[0066] In a specific implementation manner, according to the sensitivity analysis results of each main influencing factor obtained from the range analysis and multiple linear analysis, the importance of the main influencing factors for the redistribution of vadose zone moisture in the subsidence area under coal mining subsidence disturbance is compared pairwise, that is, each time two main influencing factors mi and mj are taken, and quantitatively characterize and the relative importance degree of the redistribution of vadose zone moisture in the subsidence area under coal mining subsidence disturbance. The result is represented by the matrix where the calculation result is retained to 3 significant figures, and N is the judgment matrix of each main influencing factor obtained based on the sensitivity analysis result.

[0067] Calculate the maximum eigenvalue And the eigenvector W. After normalizing the eigenvector W, the relative weight coefficients of the influencing factors for the redistribution of vadose zone moisture in the subsidence area caused by coal mining subsidence can be obtained. Then, calculate the consistency ratio of the judgment matrix N. First, calculate the CI value: .

[0068] Then, calculate RI according to the Saaty scale method, and calculate the consistency ratio CR through CI / RI. RI is the random consistency index. The random consistency index RI is related to the order of the judgment matrix (when n influencing factors are selected, the order of the judgment matrix is n), and it is scaled through the existing corresponding relationship table, which is the Saaty scale method. If the consistency ratio meets the design requirements, the weight coefficients calculated above are the weights of the influencing factors for the redistribution of vadose zone moisture in the subsidence area caused by coal mining subsidence. Otherwise, reconstruct the judgment matrix.

[0069] The present invention has important scientific research significance and application value for studying the law of redistribution of vadose zone moisture in the coal mining subsidence area, accurately determining the sensitivity of the influencing factors for the redistribution of vadose zone moisture in the subsidence area caused by coal mining subsidence, and realizing the rapid restoration of the coal mining subsidence area.

[0070] Example Two: The second embodiment of the present invention provides a sensitivity analysis system for the influencing factors of vadose zone moisture redistribution in the subsidence area, including: An experimental module configured to carry out the soil-water characteristic curve experiment under the disturbed stress path in the coal mining subsidence area; A model construction module configured to obtain the VG soil-water characteristic curve model applicable to the coal mining subsidence area; A distribution situation determination module configured to determine the redistribution situation of vadose zone moisture in the subsidence area caused by coal mining subsidence under each working condition characterized by saturation; An influencing factor sensitivity analysis module configured to perform sensitivity analysis on each main influencing factor affecting the redistribution of vadose zone moisture in the subsidence area caused by coal mining subsidence based on the range analysis method and the multiple linear regression analysis method, and rank the sensitivities of each main influencing factor.

[0071] Example Three: The third embodiment of the present invention provides a medium on which a program is stored, and when the program is executed by a processor, it implements the steps in the sensitivity analysis method for the influencing factors of vadose zone moisture redistribution in the subsidence area as described in the first embodiment of the present invention.

[0072] Example Four: Embodiment 4 of the present invention provides a device, including a memory, a processor, and a program stored on the memory and executable on the processor. When the processor executes the program, the steps in the sensitivity analysis method for influencing factors of vadose zone moisture redistribution in Embodiment 1 of the present invention are implemented.

[0073] The steps involved in Embodiments 2, 3, and 4 above correspond to those in Method Embodiment 1. For specific implementation manners, reference may be made to the relevant description part of Embodiment 1.

[0074] Those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general-purpose computer device. Optionally, they can be implemented by program codes executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0075] Although the specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solution of the present invention, various modifications or deformations that can be made without creative efforts by those skilled in the art are still within the protection scope of the present invention.

Claims

1. A sensitivity analysis method for factors affecting water redistribution in the aeration zone of a settlement area, characterized in that: The following steps are involved: Conduct soil-water characteristic curve tests under disturbance stress paths in coal mining subsidence areas; Obtain the VG soil-water characteristic curve model applicable to the coal mining subsidence area; Determine the redistribution of water in the aeration zone of the subsidence area under the disturbance of coal mining subsidence under various working conditions characterized by saturation; Based on the range analysis method and multivariate linear regression analysis method, a sensitivity analysis was conducted on the main influencing factors affecting the redistribution of moisture in the aeration zone of the subsidence area caused by coal mining subsidence, and the sensitivity of each main influencing factor was ranked.

2. The sensitivity analysis method for factors affecting water redistribution in the aeration zone of a settlement area according to claim 1, characterized in that: The specific steps for conducting soil-water characteristic curve test under disturbance stress path in coal mining subsidence settlement area are as follows: Determine the boundary range of coal mining subsidence area based on probability integral method; Carry out in-situ random sampling of the coal mining subsidence area according to the determined boundary range; Determine the disturbance stress path in coal mining subsidence settlement areas; Based on random sampling, soil-water characteristic curve test under disturbance stress path in coal mining subsidence settlement area was carried out.

3. The sensitivity analysis method for factors affecting water redistribution in the aeration zone of a settlement area according to claim 2, characterized in that: The specific steps to determine the disturbance stress path in coal mining subsidence settlement area are: Based on the measured values ​​of soil collapse and movement deformation caused by mining, the principal stress distribution in the coal mining subsidence settlement area is analyzed in combination with the elastic-plastic theory, and the disturbance stress path in the coal mining subsidence settlement area is determined. Among them, the stress states in the process of obtaining the disturbance stress path in the coal mining subsidence settlement area are successively: triaxial isostatic compression to the original horizontal stress state, continuing to increase the axial pressure to the original rock stress state, increasing the confining pressure until the sample is about to fail, and unloading the confining pressure in stages until it creeps to the original stress state.

4. The sensitivity analysis method for factors affecting water redistribution in the aeration zone of a settlement area according to claim 1, characterized in that: The specific steps to determine the redistribution of water in the aeration zone of the settlement area under coal mining subsidence disturbance characterized by saturation are as follows: Based on the VG soil-water characteristic curve model, the main influencing factors and value ranges affecting the redistribution of water in the aeration zone of the settlement area under coal mining subsidence disturbance were determined, and orthogonal experimental design was carried out. Write random crack code based on orthogonal test conditions; The random crack code and VG model were imported into COMSOL, and the values ​​of the main influencing factors under each working condition were input into COMSOL for numerical simulation; By arranging multiple monitoring lines in the numerical simulation to obtain the saturation of the monitoring lines, the average saturation of each monitoring line is taken as the saturation at the current depth, so as to determine the moisture redistribution of the aeration zone in the subsidence area under coal mining subsidence disturbance under various working conditions.

5. The sensitivity analysis method for factors affecting water redistribution in the aeration zone of a settlement area according to claim 4, characterized in that: Due to the interaction between the mining area's stratigraphic structure, hydrogeological conditions and mining conditions, the soil type, porosity, number of cracks, permeability coefficient of the vadose zone, fracture permeability coefficient and coal seam thickness were determined as the main influencing factors of moisture redistribution in the vadose zone in the subsidence area under coal mining subsidence disturbance.

6. The sensitivity analysis method for factors affecting water redistribution in the aeration zone of a settlement area according to claim 4, characterized in that: The specific steps of sensitivity analysis of the main influencing factors affecting the redistribution of moisture in the aeration zone of the settlement area under coal mining subsidence disturbance based on the range analysis method and multivariate linear regression analysis method are as follows: Multivariate linear analysis was performed on the average saturation of representative monitoring lines and the values ​​of the main influencing factors under each working condition; The average saturation of representative monitoring lines and the values ​​of main influencing factors under various working conditions are analyzed for range. The results of range analysis and multivariate linear regression analysis are comprehensively considered to analyze the sensitivity of the main influencing factors affecting the redistribution of moisture in the vadose zone under coal mining subsidence disturbance, and finally the sensitivity ranking of each main influencing factor is obtained.

7. The sensitivity analysis method for factors affecting water redistribution in the aeration zone of a settlement area according to claim 6, characterized in that: Based on the sensitivity analysis results of each main factor, the weight of each main influencing factor was determined by the analytic hierarchy process (AHP) method based on multiple linear regression and range analysis, and the sensitivity analysis ranking of each main influencing factor was verified.

8. A sensitivity analysis system for factors affecting water redistribution in the aeration zone of a settlement area, characterized in that: include: The test module is configured to carry out soil-water characteristic curve tests under the disturbance stress path in coal mining subsidence settlement areas; A model building module is configured to obtain a VG soil-water characteristic curve model suitable for the coal mining subsidence settlement area; A distribution determination module is configured to determine the redistribution of moisture in the aeration zone of the subsidence area under the disturbance of coal mining subsidence under various working conditions characterized by saturation; The influencing factor sensitivity analysis module is configured to conduct sensitivity analysis on the main influencing factors affecting the redistribution of moisture in the aeration zone of the subsidence area under coal mining subsidence disturbance based on the range analysis method and the multivariate linear regression analysis method, and to rank the sensitivity of each main influencing factor.

9. A computer-readable storage medium, characterized in that: A plurality of instructions are stored therein, and the instructions are suitable for being loaded by a processor of a terminal device and executing the sensitivity analysis method of factors affecting moisture redistribution in aeration zones of a settlement area according to any one of claims 1 to 7.

10. A terminal device, characterized in that: It includes a processor and a computer-readable storage medium, the processor is used to implement various instructions; the computer-readable storage medium is used to store multiple instructions, and the instructions are suitable for being loaded by the processor and executing the sensitivity analysis method of factors affecting moisture redistribution in the aeration zone of the settlement area according to any one of claims 1-7.

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