Coupling evaluation method for water filling strength of coal seam roof containing aquifer

Abstract

This invention discloses a coupled evaluation method for the water-bearing intensity of multiple aquifers in the roof of a coal seam, specifically implemented according to the following steps: Step 1, establish a database of the main controlling factors of water-bearing and conductive characteristics for each aquifer and evaluate the water-bearing and conductive characteristics of the corresponding aquifers to obtain a zoning map of the water-bearing and conductive characteristics of each aquifer; Step 2, calculate the influence weight of each aquifer on the comprehensive zoning of the water-bearing and conductive characteristics of the aquifers in the roof of the coal seam; Step 3, based on the influence weights calculated in Step 2, superimpose the zoning maps of the water-bearing and conductive characteristics of each aquifer to obtain a comprehensive zoning map of the water-bearing and conductive characteristics of the aquifers in the roof of the coal seam; Step 4, calculate and draw the mining-induced damage index and its zoning map of the aquifers in the roof of the coal seam; Step 5, superimpose the comprehensive zoning map of the water-bearing and conductive characteristics of the aquifers in the roof of the coal seam and the zoning map of the mining-induced damage index of the aquifers in the roof of the coal seam to obtain a comprehensive zoning map of the water-bearing intensity of the roof of the coal seam. This invention can achieve a comprehensive evaluation of the water-bearing intensity under conditions of multiple aquifers in the roof of a coal seam.

Description

Technical Field

[0001] This invention belongs to the technical field of coal seam roof aquifer evaluation methods, and relates to a coupled evaluation method for the water-filling intensity of multiple aquifers in the coal seam roof. Background Technology

[0002] Chinese patent "A Method for Evaluating the Water-Refilling Intensity of Sandstone Aquifers in Coal Seam Roofs" (Authorization Announcement No.: CN111695303B, Announcement Date: 2023-08-18) defines water-filling intensity and provides a detailed evaluation method. The main steps include determining the directly water-filled aquifers in the coal seam roof, determining the main controlling factors of water-filling intensity in the coal seam roof, quantifying the main controlling factors, drawing thematic maps and establishing a database of quantified main controlling factors, determining the influence weight of each main controlling factor on the water-filling intensity of the sandstone aquifers in the roof, constructing a roof water-filling intensity evaluation model to calculate the water-filling intensity index, and evaluating and zoning the roof water-filling intensity. When there is only one water-bearing aquifer in the coal seam roof, the above method can be used for evaluation. The evaluation results can be correlated with the water inflow at the mining face, and the application effect is good. However, if there are two or more water-bearing aquifers directly in the coal seam roof, if the above method is used to evaluate each aquifer separately, multiple unrelated water-bearing intensity evaluation results will be obtained, i.e., multiple two-dimensional planar datasets. However, the water inflow at the mining face is a single two-dimensional planar dataset. Therefore, the multiple water-bearing intensity evaluation results cannot be correlated with the water inflow at the mining face, and it is impossible to verify the evaluation results or predict the water inflow during mining. Therefore, it is necessary to effectively couple the evaluation results of water inflow intensity of multiple aquifers to form a single comprehensive zoning of coal seam roof water inflow intensity. Some scholars have also used the average proportion of single-hole water inflow of each aquifer obtained from downhole water exploration and drainage data to superimpose the water inflow intensity of each aquifer. However, this method cannot reflect the differences in hydrogeological parameters in different regions. The influence weight of each aquifer on the comprehensive zoning of water inflow intensity is different in each region. It is necessary to further explore the differences in hydrogeological parameters in different regions to determine the influence weight of each aquifer on the comprehensive zoning of water inflow intensity in each region. Only in this way can the comprehensive zoning results of coal seam roof water inflow intensity under multiple aquifer conditions be more accurate and have greater promotion and application value. Summary of the Invention

[0003] The purpose of this invention is to provide a coupled evaluation method for the water inflow intensity of multiple aquifers in the roof of a coal seam, which can realize a comprehensive evaluation of the water inflow intensity under the condition of multiple aquifers in the roof of a coal seam.

[0004] The technical solution adopted in this invention is a coupled evaluation method for the water-filling intensity of multiple aquifers in the roof of a coal seam, which is implemented according to the following steps:

[0005] Step 1: Establish a database of the main controlling factors of water-conducting characteristics for each aquifer and evaluate the water-conducting characteristics of the corresponding aquifer to obtain a zoning map of the water-conducting characteristics of each aquifer.

[0006] Step 2: Calculate the influence weight of each aquifer on the comprehensive zoning of the water-conducting characteristics of the aquifer in the roof of the coal seam;

[0007] Step 3: Based on the influence weights calculated in Step 2, superimpose the water-conducting characteristic zoning maps of each aquifer to obtain a comprehensive zoning map of the water-conducting characteristics of the aquifers in the coal seam roof.

[0008] Step 4: Calculate and plot the mining-induced failure index and its zoning map of the aquifer in the coal seam roof;

[0009] Step 5: Overlay the comprehensive zoning map of the water-conducting characteristics of the aquifer on the roof of the coal seam with the zoning map of the mining-induced damage index of the aquifer on the roof of the coal seam to obtain the comprehensive zoning map of the water-filling intensity of the roof of the coal seam.

[0010] The invention is further characterized in that:

[0011] Step 1 specifically involves: determining the main controlling factors of the water-conducting characteristics of each aquifer based on geological and hydrogeological data; quantifying and normalizing the main controlling factors of the water-conducting characteristics of the aquifer; establishing a database of the corresponding aquifers; calculating the weights of each main controlling factor for the corresponding aquifer; and then drawing a zoning map of the water-conducting characteristics of the corresponding aquifer based on the database of the corresponding aquifers and the weights of the main controlling factors. This is the evaluation result of the water-conducting characteristics of each aquifer.

[0012] The main controlling factors of the water-conductivity characteristics of each aquifer are multiple factors including aquifer thickness, permeability coefficient, unit yield, sedimentary environment index, core recovery rate, tectonic development index, and aquifer mining damage index.

[0013] ArcGIS software was used to draw the aquifer water-conducting characteristic zoning map in step 1.

[0014] Step 2 is as follows:

[0015] Based on the permeability and porosity data of the study area, a fitting formula for the relationship between permeability and porosity in the study area was obtained:

[0016] K=aΦ m Formula 1

[0017] Where K is the permeability coefficient; a and m are constants, %; and Φ is the porosity, %;

[0018] According to Equation 1, the specific value of parameter m is obtained;

[0019] Then, according to Equation 1, the influence weight of aquifer i on the water-conducting characteristics of the aquifer in the coal roof is calculated using the following formula:

[0020]

[0021] In the formula, W i (x, y) is the weighting function for the influence of aquifer i on the comprehensive zoning of the water-conducting characteristics of the top aquifer, H i (x,y) is a function of the thickness of aquifer i, K i (x,y) is the permeability coefficient function of aquifer i, L is the total number of aquifers, m is a constant in Equation 1, and x and y are the location coordinates.

[0022] Step 3 specifically involves:

[0023] Calculate the comprehensive index of water conductivity characteristics of the aquifer in the roof of the coal seam according to Equation 4:

[0024]

[0025] Where HD(x,y) is the comprehensive exponential function of the water-conductivity characteristics of the aquifer in the roof of the coal seam; f i (x,y) is the water-conducting characteristic function of aquifer i, where x and y are the position coordinates;

[0026] Calculate the comprehensive index of water-conducting characteristics of the aquifer in the roof of the coal seam based on HD(x,y), and draw a comprehensive zoning map of the water-conducting characteristics of the aquifer in the roof of the coal seam.

[0027] Step 4 is as follows:

[0028] The Mining-Induced Failure Index (AMFI) for coal seam roof aquifers is defined based on the differences in water conductivity between the caving zone and the water-conducting fracture zone, and between different strata within the water-conducting fracture zone. It comprehensively analyzes the spatial relationship between the aquifer, the caving zone, and the water-conducting fracture zone, calculating a quantitative value that comprehensively reflects the water conductivity of the aquifer after mining-induced damage. The maximum value is 1, and the minimum value is 0. The maximum value is defined as the aquifer being completely located within the caving zone, and the minimum value is defined as the aquifer being completely located above the water-conducting fracture zone, unaffected by mining-induced damage. The calculation method is the ratio of the product of the thickness of each aquifer and the water conductivity of the water-conducting fracture zone at that aquifer to the total thickness of the aquifer. The water conductivity of the water-conducting fracture zone is defined as a piecewise function, where the caving zone is defined as 1, and the uppermost boundary of the fracture zone and above it is defined as 0. The decay function of the water conductivity of the strata within the fracture zone is linear. Therefore, the formula for calculating the Mining-Induced Failure Index (AMFI) for coal seam roof aquifers is:

[0029]

[0030] in,

[0031] Where AMFI(x,y) is the mining-induced failure exponential function of the aquifer in the roof of the coal seam; h i f is the thickness of the i-th aquifer within the roof of the coal seam.(x,y) (h i Let be the water conductivity function of the i-th aquifer within the roof of the coal seam, where x and y are the position coordinates, and H is the water conductivity function. k H represents the height of the landslide zone. d The height of the water-conducting fracture zone;

[0032] After calculation according to Equations 4 and 5, a zoning map of the mining-induced damage index of the aquifer in the roof of the coal seam is drawn using geographic information software.

[0033] Step 5 specifically involves:

[0034] The comprehensive index FI of water-bearing intensity of multiple aquifers in the roof of a coal seam is calculated as follows:

[0035] FI=W3HD(x,y)+W4AMFI(x,y) Equation 6

[0036] Among them, W3 is the zoning weight of the comprehensive index of water-conducting characteristics of the aquifer in the roof of the coal seam, and W4 is the zoning weight of the mining-induced damage index of the aquifer in the roof of the coal seam.

[0037] Based on the comprehensive index FI of water inflow intensity of multiple aquifers in the coal seam roof, the natural discontinuity zoning method built into ArcGIS software was used to zonate the coal seam roof and obtain a comprehensive zoning map of water inflow intensity.

[0038] The beneficial effects of this invention are:

[0039] This invention utilizes the differences in hydrogeological parameters of various aquifers in different regions to establish a correlation model between the influence weights of hydrogeological parameters and the water-conducting characteristics of the aquifers in the roof of the coal seam. Then, by superimposing the comprehensive zoning of the water-conducting characteristics of the aquifers in the roof of the coal seam with the mining-induced damage index zoning, a comprehensive zoning of the water-filling intensity of the aquifers in the roof of the coal seam is obtained. This enables a comprehensive evaluation of the water-filling intensity of the roof of the coal seam under multiple aquifer conditions, making the evaluation results more practically valuable and providing technical support for predicting water inflow during the mining process. Attached Figure Description

[0040] Figure 1 This is a water-conducting characteristic zoning map of the three sections of the Yan'an Formation obtained in Example 7 of the coupled evaluation method for the water-filling intensity of multiple aquifers in the coal seam roof of the present invention.

[0041] Figure 2 This is a water-conducting characteristic partition map of a section of the Zhiluo Formation aquifer obtained in Example 7 of the coupled evaluation method for the water-filling intensity of multiple aquifers in the coal seam roof of the present invention.

[0042] Figure 3 This is a fitting diagram of the relationship between porosity and permeability coefficient obtained in Example 7 of the coupled evaluation method for the water-filling intensity of multiple aquifers in the coal seam roof of the present invention;

[0043] Figure 4 This is the weighted partition map of the water-bearing characteristics of the three sections of the Yan'an Formation obtained in Example 7 of the coupled evaluation method for the water-bearing intensity of multiple aquifers in the coal seam roof of the present invention.

[0044] Figure 5 This is a weighted partition map of water-conducting characteristics of a section of the Zhiluo Formation obtained in Example 7 of the coupled evaluation method for the water-filling intensity of multiple aquifers in the coal seam roof of the present invention.

[0045] Figure 6 This is a comprehensive zoning map of the water-conducting characteristics of the aquifers in the coal seam roof obtained in Example 7 of the coupled evaluation method for the water-filling intensity of multiple aquifers in the coal seam roof of the present invention;

[0046] Figure 7 This is a coal mine roof aquifer mining failure index zoning map obtained in Example 7 of the coupled evaluation method for the water-filling intensity of multiple aquifers in the coal seam roof of the present invention.

[0047] Figure 8 This is a comprehensive zoning map of the water inflow intensity of the coal seam roof obtained in Example 7 of the coupled evaluation method for the water inflow intensity of multiple aquifers in the coal seam roof of the present invention. Detailed Implementation

[0048] The following detailed description is provided in conjunction with specific implementation methods.

[0049] Example 1

[0050] The coupled evaluation method for the water-bearing intensity of multiple aquifers in the roof of a coal seam of the present invention is implemented according to the following steps:

[0051] Step 1: Establish a database of the main controlling factors of water-conducting characteristics for each aquifer and evaluate the water-conducting characteristics of the corresponding aquifer to obtain a zoning map of the water-conducting characteristics of each aquifer.

[0052] Step 2: Calculate the influence weight of each aquifer on the comprehensive zoning of the water-conducting characteristics of the aquifer in the roof of the coal seam;

[0053] Step 3: Based on the influence weights calculated in Step 2, superimpose the water-conducting characteristic zoning maps of each aquifer to obtain a comprehensive zoning map of the water-conducting characteristics of the aquifers in the coal seam roof.

[0054] Step 4: Calculate and plot the mining-induced failure index and its zoning map of the aquifer in the coal seam roof;

[0055] Step 5: Overlay the comprehensive zoning map of the water-conducting characteristics of the aquifer on the roof of the coal seam with the zoning map of the mining-induced damage index of the aquifer on the roof of the coal seam to obtain the comprehensive zoning map of the water-filling intensity of the roof of the coal seam.

[0056] Example 2

[0057] The coupled evaluation method for the water-bearing intensity of multiple aquifers in the roof of a coal seam of the present invention is implemented according to the following steps:

[0058] Step 1: Establish a database of the main controlling factors of the water-conducting characteristics of each aquifer and evaluate the water-conducting characteristics of the corresponding aquifers to obtain a zoning map of the water-conducting characteristics of each aquifer. Determine the main controlling factors of the water-conducting characteristics of each aquifer based on geological and hydrogeological data. Then, quantify and normalize the main controlling factors of the water-conducting characteristics of the aquifers and establish a database of the corresponding aquifers. Then, calculate the weight of each main controlling factor using calculation methods such as subjective weight and objective weight. Finally, draw the zoning map of the water-conducting characteristics of the corresponding aquifers based on the database of the corresponding aquifers and the weight of the main controlling factors. This is the evaluation result of the water-conducting characteristics of each aquifer.

[0059] The main controlling factors of the water-conductivity characteristics of each aquifer are multiple of the following: aquifer thickness, permeability coefficient, unit yield, sedimentary environment index, core recovery rate, tectonic development index, and aquifer mining failure index.

[0060] ArcGIS software was used to draw the aquifer water-conducting characteristic zoning map.

[0061] Step 2: Calculate the influence weight of each aquifer on the comprehensive zoning of the water-conducting characteristics of the aquifer in the roof of the coal seam;

[0062] Step 3: Based on the influence weights calculated in Step 2, superimpose the water-conducting characteristic zoning maps of each aquifer to obtain a comprehensive zoning map of the water-conducting characteristics of the aquifers in the coal seam roof.

[0063] Step 4: Calculate and plot the mining-induced failure index and its zoning map of the aquifer in the coal seam roof;

[0064] Step 5: Overlay the comprehensive zoning map of the water-conducting characteristics of the aquifer on the roof of the coal seam with the zoning map of the mining-induced damage index of the aquifer on the roof of the coal seam to obtain the comprehensive zoning map of the water-filling intensity of the roof of the coal seam.

[0065] Example 3

[0066] The coupled evaluation method for the water-bearing intensity of multiple aquifers in the roof of a coal seam of the present invention is implemented according to the following steps:

[0067] Step 1: Establish a database of the main controlling factors of the water-conducting characteristics of each aquifer and evaluate the water-conducting characteristics of the corresponding aquifers to obtain a zoning map of the water-conducting characteristics of each aquifer. Determine the main controlling factors of the water-conducting characteristics of each aquifer based on geological and hydrogeological data. Then, quantify and normalize the main controlling factors of the water-conducting characteristics of the aquifers and establish a database of the corresponding aquifers. Then, calculate the weight of each main controlling factor using calculation methods such as subjective weight and objective weight. Finally, draw the zoning map of the water-conducting characteristics of the corresponding aquifers based on the database of the corresponding aquifers and the weight of the main controlling factors. This is the evaluation result of the water-conducting characteristics of each aquifer.

[0068] The main controlling factors of the water-conductivity characteristics of each aquifer are multiple of the following: aquifer thickness, permeability coefficient, unit yield, sedimentary environment index, core recovery rate, tectonic development index, and aquifer mining failure index.

[0069] ArcGIS software was used to draw the aquifer water-conducting characteristic zoning map.

[0070] Step 2: Calculate the influence weight of each aquifer on the comprehensive zoning of the water-conducting characteristics of the aquifer in the coal seam roof, specifically as follows:

[0071] Specifically, based on the permeability and porosity data of the study area, a fitting formula between the permeability and porosity of the study area is obtained:

[0072] K=aΦ m Formula 1

[0073] Where K is the permeability coefficient; a and m are constants, %; and Φ is the porosity, %;

[0074] According to Equation 1, the specific value of parameter m is obtained;

[0075] Then, according to Equation 1, the influence weight of aquifer i on the water-conducting characteristics of the aquifer in the coal roof is calculated using the following formula:

[0076]

[0077] In the formula, W i (x, y) is the weighting function for the influence of aquifer i on the comprehensive zoning of the water-conducting characteristics of the top aquifer, H i (x,y) is a function of the thickness of aquifer i, K i (x,y) is the permeability coefficient function of aquifer i, L is the total number of aquifers, m is a constant in Equation 1, and x and y are the location coordinates;

[0078] Step 3: Based on the influence weights calculated in Step 2, superimpose the water-conducting characteristic zoning maps of each aquifer to obtain a comprehensive zoning map of the water-conducting characteristics of the aquifers in the coal seam roof.

[0079] Step 4: Calculate and plot the mining-induced failure index and its zoning map of the aquifer in the coal seam roof;

[0080] Step 5: Overlay the comprehensive zoning map of the water-conducting characteristics of the aquifer on the roof of the coal seam with the zoning map of the mining-induced damage index of the aquifer on the roof of the coal seam to obtain the comprehensive zoning map of the water-filling intensity of the roof of the coal seam.

[0081] Example 4

[0082] The coupled evaluation method for the water-bearing intensity of multiple aquifers in the roof of a coal seam of the present invention is implemented according to the following steps:

[0083] Step 1: Establish a database of the main controlling factors of the water-conducting characteristics of each aquifer and evaluate the water-conducting characteristics of the corresponding aquifers to obtain a zoning map of the water-conducting characteristics of each aquifer. Determine the main controlling factors of the water-conducting characteristics of each aquifer based on geological and hydrogeological data. Then, quantify and normalize the main controlling factors of the water-conducting characteristics of the aquifers and establish a database of the corresponding aquifers. Then, calculate the weight of each main controlling factor using calculation methods such as subjective weight and objective weight. Finally, draw the zoning map of the water-conducting characteristics of the corresponding aquifers based on the database of the corresponding aquifers and the weight of the main controlling factors. This is the evaluation result of the water-conducting characteristics of each aquifer.

[0084] The main controlling factors of the water-conductivity characteristics of each aquifer are multiple of the following: aquifer thickness, permeability coefficient, unit yield, sedimentary environment index, core recovery rate, tectonic development index, and aquifer mining failure index.

[0085] ArcGIS software was used to draw the aquifer water-conducting characteristic zoning map.

[0086] Step 2: Calculate the influence weight of each aquifer on the comprehensive zoning of the water-conducting characteristics of the aquifer in the coal seam roof, specifically as follows:

[0087] Specifically, based on the permeability and porosity data of the study area, a fitting formula between the permeability and porosity of the study area is obtained:

[0088] K=aΦ m Formula 1

[0089] Where K is the permeability coefficient; a and m are constants, %; and Φ is the porosity, %;

[0090] According to Equation 1, the specific value of parameter m is obtained;

[0091] Then, according to Equation 1, the influence weight of aquifer i on the water-conducting characteristics of the aquifer in the coal roof is calculated using the following formula:

[0092]

[0093] In the formula, W i (x, y) is the weighting function for the influence of aquifer i on the comprehensive zoning of the water-conducting characteristics of the top aquifer, H i (x,y) is a function of the thickness of aquifer i, K i (x,y) is the permeability coefficient function of aquifer i, L is the total number of aquifers, m is a constant in Equation 1, and x and y are the location coordinates;

[0094] Step 3: Based on the influence weights calculated in Step 2, superimpose the water-conductivity characteristic zoning maps of each aquifer to obtain a comprehensive zoning map of the water-conductivity characteristics of the coal seam roof aquifers, specifically:

[0095] Calculate the comprehensive index of water conductivity characteristics of the aquifer in the roof of the coal seam according to Equation 4:

[0096]

[0097] Where HD(x,y) is the comprehensive exponential function of the water-conductivity characteristics of the aquifer in the roof of the coal seam; f i (x,y) is the water-conducting characteristic function of aquifer i, where x and y are the position coordinates;

[0098] Calculate the comprehensive index of water-conductivity characteristics of the aquifer in the roof of the coal seam based on HD(x,y), and draw a comprehensive zoning map of the water-conductivity characteristics of the aquifer in the roof of the coal seam.

[0099] Step 4: Calculate and plot the mining-induced failure index and its zoning map of the aquifer in the coal seam roof;

[0100] Step 5: Overlay the comprehensive zoning map of the water-conducting characteristics of the aquifer on the roof of the coal seam with the zoning map of the mining-induced damage index of the aquifer on the roof of the coal seam to obtain the comprehensive zoning map of the water-filling intensity of the roof of the coal seam.

[0101] Example 5

[0102] The coupled evaluation method for the water-bearing intensity of multiple aquifers in the roof of a coal seam of the present invention is implemented according to the following steps:

[0103] Step 1: Establish a database of the main controlling factors of the water-conducting characteristics of each aquifer and evaluate the water-conducting characteristics of the corresponding aquifers to obtain a zoning map of the water-conducting characteristics of each aquifer. Determine the main controlling factors of the water-conducting characteristics of each aquifer based on geological and hydrogeological data. Then, quantify and normalize the main controlling factors of the water-conducting characteristics of the aquifers and establish a database of the corresponding aquifers. Then, calculate the weight of each main controlling factor using calculation methods such as subjective weight and objective weight. Finally, draw the zoning map of the water-conducting characteristics of the corresponding aquifers based on the database of the corresponding aquifers and the weight of the main controlling factors. This is the evaluation result of the water-conducting characteristics of each aquifer.

[0104] The main controlling factors of the water-conductivity characteristics of each aquifer are multiple of the following: aquifer thickness, permeability coefficient, unit yield, sedimentary environment index, core recovery rate, tectonic development index, and aquifer mining failure index.

[0105] ArcGIS software was used to draw the aquifer water-conducting characteristic zoning map.

[0106] Step 2: Calculate the influence weight of each aquifer on the comprehensive zoning of the water-conducting characteristics of the aquifer in the coal seam roof, specifically as follows:

[0107] Specifically, based on the permeability and porosity data of the study area, a fitting formula between the permeability and porosity of the study area is obtained:

[0108] K=aΦm Formula 1

[0109] Where K is the permeability coefficient; a and m are constants, %; and Φ is the porosity, %;

[0110] According to Equation 1, the specific value of parameter m is obtained;

[0111] Then, according to Equation 1, the influence weight of aquifer i on the water-conducting characteristics of the aquifer in the coal roof is calculated using the following formula:

[0112]

[0113] In the formula, W i (x, y) is the weighting function for the influence of aquifer i on the comprehensive zoning of the water-conducting characteristics of the top aquifer, H i (x,y) is a function of the thickness of aquifer i, K i (x,y) is the permeability coefficient function of aquifer i, L is the total number of aquifers, m is a constant in Equation 1, and x and y are the location coordinates;

[0114] Step 3: Based on the influence weights calculated in Step 2, superimpose the water-conductivity characteristic zoning maps of each aquifer to obtain a comprehensive zoning map of the water-conductivity characteristics of the coal seam roof aquifers, specifically:

[0115] Calculate the comprehensive index of water conductivity characteristics of the aquifer in the roof of the coal seam according to Equation 4:

[0116]

[0117] Where HD(x,y) is the comprehensive exponential function of the water-conductivity characteristics of the aquifer in the roof of the coal seam; f i (x,y) is the water-conducting characteristic function of aquifer i, where x and y are the position coordinates;

[0118] Calculate the comprehensive index of water-conductivity characteristics of the aquifer in the roof of the coal seam based on HD(x,y), and draw a comprehensive zoning map of the water-conductivity characteristics of the aquifer in the roof of the coal seam.

[0119] Step 4: Calculate and plot the mining-induced failure index and its zoning map of the aquifer in the coal seam roof, specifically as follows:

[0120] The Mining-Induced Failure Index (AMFI) for coal seam roof aquifers is defined based on the differences in water conductivity between the caving zone and the water-conducting fracture zone, and between different strata within the water-conducting fracture zone. It comprehensively analyzes the spatial relationship between the aquifer, the caving zone, and the water-conducting fracture zone, calculating a quantitative value that comprehensively reflects the water conductivity of the aquifer after mining-induced damage. The maximum value is 1, and the minimum value is 0. The maximum value is defined as the aquifer being completely located within the caving zone, and the minimum value is defined as the aquifer being completely located above the water-conducting fracture zone, unaffected by mining-induced damage. The calculation method is the ratio of the product of the thickness of each aquifer and the water conductivity of the water-conducting fracture zone at that aquifer to the total thickness of the aquifer. The water conductivity of the water-conducting fracture zone is defined as a piecewise function, where the caving zone is defined as 1, and the uppermost boundary of the fracture zone and above it is defined as 0. The decay function of the water conductivity of the strata within the fracture zone is linear. Therefore, the formula for calculating the Mining-Induced Failure Index (AMFI) for coal seam roof aquifers is:

[0121]

[0122] in,

[0123] Where AMFI(x,y) is the mining-induced failure exponential function of the aquifer in the roof of the coal seam; h i f is the thickness of the i-th aquifer within the roof of the coal seam. (x,y) (h i Let be the water conductivity function of the i-th aquifer within the roof of the coal seam, where x and y are the position coordinates, and H is the water conductivity function. k H represents the height of the landslide zone. d The height of the water-conducting fracture zone;

[0124] After calculation according to Equations 4 and 5, a zoning map of the mining-induced damage index of the aquifer in the roof of the coal seam is drawn using geographic information software.

[0125] Step 5: Overlay the comprehensive zoning map of the water-conducting characteristics of the aquifer on the roof of the coal seam with the zoning map of the mining-induced damage index of the aquifer on the roof of the coal seam to obtain the comprehensive zoning map of the water-filling intensity of the roof of the coal seam.

[0126] Example 6

[0127] The coupled evaluation method for the water-bearing intensity of multiple aquifers in the roof of a coal seam of the present invention is implemented according to the following steps:

[0128] Step 1: Establish a database of the main controlling factors of the water-conducting characteristics of each aquifer and evaluate the water-conducting characteristics of the corresponding aquifers to obtain a zoning map of the water-conducting characteristics of each aquifer. Determine the main controlling factors of the water-conducting characteristics of each aquifer based on geological and hydrogeological data. Then, quantify and normalize the main controlling factors of the water-conducting characteristics of the aquifers and establish a database of the corresponding aquifers. Then, calculate the weight of each main controlling factor using calculation methods such as subjective weight and objective weight. Finally, draw the zoning map of the water-conducting characteristics of the corresponding aquifers based on the database of the corresponding aquifers and the weight of the main controlling factors. This is the evaluation result of the water-conducting characteristics of each aquifer.

[0129] The main controlling factors of the water-conductivity characteristics of each aquifer are multiple of the following: aquifer thickness, permeability coefficient, unit yield, sedimentary environment index, core recovery rate, tectonic development index, and aquifer mining failure index.

[0130] ArcGIS software was used to draw the aquifer water-conducting characteristic zoning map.

[0131] Step 2: Calculate the influence weight of each aquifer on the comprehensive zoning of the water-conducting characteristics of the aquifer in the coal seam roof, specifically as follows:

[0132] Specifically, based on the permeability and porosity data of the study area, a fitting formula between the permeability and porosity of the study area is obtained:

[0133] K=aΦ m Formula 1

[0134] Where K is the permeability coefficient; a and m are constants, %; and Φ is the porosity, %;

[0135] According to Equation 1, the specific value of parameter m is obtained;

[0136] Then, according to Equation 1, the influence weight of aquifer i on the water-conducting characteristics of the aquifer in the coal roof is calculated using the following formula:

[0137]

[0138] In the formula, W i (x, y) is the weighting function for the influence of aquifer i on the comprehensive zoning of the water-conducting characteristics of the top aquifer, H i (x,y) is a function of the thickness of aquifer i, K i (x,y) is the permeability coefficient function of aquifer i, L is the total number of aquifers, m is a constant in Equation 1, and x and y are the location coordinates;

[0139] Step 3: Based on the influence weights calculated in Step 2, superimpose the water-conductivity characteristic zoning maps of each aquifer to obtain a comprehensive zoning map of the water-conductivity characteristics of the coal seam roof aquifers, specifically:

[0140] Calculate the comprehensive index of water conductivity characteristics of the aquifer in the roof of the coal seam according to Equation 4:

[0141]

[0142] Where HD(x,y) is the comprehensive exponential function of the water-conductivity characteristics of the aquifer in the roof of the coal seam; f i (x,y) is the water-conducting characteristic function of aquifer i, where x and y are the position coordinates;

[0143] Calculate the comprehensive index of water-conductivity characteristics of the aquifer in the roof of the coal seam based on HD(x,y), and draw a comprehensive zoning map of the water-conductivity characteristics of the aquifer in the roof of the coal seam.

[0144] Step 4: Calculate and plot the mining-induced failure index and its zoning map of the aquifer in the coal seam roof, specifically as follows:

[0145] The Mining-Induced Failure Index (AMFI) for coal seam roof aquifers is defined based on the differences in water conductivity between the caving zone and the water-conducting fracture zone, and between different strata within the water-conducting fracture zone. It comprehensively analyzes the spatial relationship between the aquifer, the caving zone, and the water-conducting fracture zone, calculating a quantitative value that comprehensively reflects the water conductivity of the aquifer after mining-induced damage. The maximum value is 1, and the minimum value is 0. The maximum value is defined as the aquifer being completely located within the caving zone, and the minimum value is defined as the aquifer being completely located above the water-conducting fracture zone, unaffected by mining-induced damage. The calculation method is the ratio of the product of the thickness of each aquifer and the water conductivity of the water-conducting fracture zone at that aquifer to the total thickness of the aquifer. The water conductivity of the water-conducting fracture zone is defined as a piecewise function, where the caving zone is defined as 1, and the uppermost boundary of the fracture zone and above it is defined as 0. The decay function of the water conductivity of the strata within the fracture zone is linear. Therefore, the formula for calculating the Mining-Induced Failure Index (AMFI) for coal seam roof aquifers is:

[0146]

[0147] in,

[0148] Where AMFI(x,y) is the mining-induced failure exponential function of the aquifer in the roof of the coal seam; h i f is the thickness of the i-th aquifer within the roof of the coal seam. (x,y) (h i Let be the water conductivity function of the i-th aquifer within the roof of the coal seam, where x and y are the position coordinates, and H is the water conductivity function. k H represents the height of the landslide zone. d The height of the water-conducting fracture zone;

[0149] After calculation according to Equations 4 and 5, a zoning map of the mining-induced damage index of the aquifer in the roof of the coal seam is drawn using geographic information software.

[0150] Step 5: Overlay the comprehensive zoning map of the water-bearing characteristics of the aquifer on the roof of the coal seam with the zoning map of the mining-induced failure index of the aquifer on the roof of the coal seam to obtain the comprehensive zoning map of the water-bearing intensity of the roof of the coal seam, specifically:

[0151] The comprehensive index FI of water-bearing intensity of multiple aquifers in the roof of a coal seam is calculated as follows:

[0152] FI=W3HD(x,y)+W4AMFI(x,y) Equation 6

[0153] Among them, W3 is the zoning weight of the comprehensive index of water-conducting characteristics of the aquifer in the roof of the coal seam, and W4 is the zoning weight of the mining-induced damage index of the aquifer in the roof of the coal seam. The weight calculation method adopts the common subjective weight and objective weight calculation method.

[0154] Based on the comprehensive index FI of water inflow intensity of multiple aquifers in the coal seam roof, the natural discontinuity zoning method built into ArcGIS software was used to zonate the coal seam roof and obtain a comprehensive zoning map of water inflow intensity.

[0155] Example 7

[0156] Based on Example 6, this example describes coal mining in a study area. The directly water-bearing aquifers on the roof of the coal seam are the third section of the Yan'an Formation and the first section of the Zhiluo Formation. According to the analysis of geological and hydrogeological data, the main controlling factors of the aquifer's water-conductivity characteristics include aquifer thickness, sedimentary environment influence index, core recovery rate, and permeability coefficient. The weights of each factor, calculated using the analytic hierarchy process (AHP), are 0.32, 0.19, 0.07, and 0.42, respectively. ArcGIS software was used for mapping, and the evaluation results of the water-conductivity characteristics of each aquifer are as follows: Figure 1 and Figure 2 As shown;

[0157] Step 2: Calculate the influence weight of each aquifer on the comprehensive zoning of the water-conducting characteristics of the aquifer in the coal seam roof.

[0158] First, based on the permeability and porosity data of the study area, a fitting formula for the relationship between permeability and porosity was obtained through fitting. The fitting function for permeability and porosity follows a power function relationship. The fitting formula is as follows:

[0159] K = 10 -8 Φ 7.3 Formula 1

[0160] In the formula, K is the permeability coefficient; Φ is the porosity, resulting in m being 7.3;

[0161] The fitted curve is as follows Figure 3 As shown;

[0162] Then, according to Equation 1, the following formula is used to calculate the influence weights of the two aquifers on the water-conducting characteristics of the aquifer in the coal roof:

[0163]

[0164] In the formula, W i (x, y) is the weighting function for the influence of aquifer i on the comprehensive zoning of the water-conducting characteristics of the top aquifer, H i (x,y) is a function of the thickness of aquifer i, K i (x,y) is the permeability coefficient function of aquifer i, L is the total number of aquifers, L=2 in this embodiment, m is a constant in Equation 1, and x and y are position coordinates;

[0165] W1(x,y) and W2(x,y) were calculated. W1(x,y) is the influence weight function of the three sections of the Yan'an Formation on the comprehensive zoning of the top aquifer with water-conducting characteristics. W2(x,y) is the influence weight function of the first section of the Zhiluo Formation on the comprehensive zoning of the top aquifer with water-conducting characteristics.

[0166] Based on W1(x,y) and W2(x,y), the weighted partition maps of the three sections of the Yan'an Formation and the first section of the Zhiluo Formation containing water-conducting characteristics are obtained, respectively. Figure 4 and Figure 5 As shown.

[0167] Step 3: Based on the influence weights calculated in Step 2, superimpose the water-conducting characteristic zoning maps of each aquifer to obtain a comprehensive zoning map of the water-conducting characteristics of the aquifers in the coal seam roof.

[0168] The comprehensive index of water-conducting characteristics of aquifers in the roof of coal seams is calculated as follows. The zoning method adopted is the natural discontinuity zoning method built into ArcGIS software.

[0169] HD(x,y)=W1f1(x,y)+W2f2(x,y) Equation 4

[0170] In the formula: HD(x,y) is the comprehensive index function of water-conducting characteristics of the aquifer in the roof of the coal seam; f1(x,y) is the water-conducting characteristic function of the third section of the Yan'an Formation aquifer; f2(x,y) is the water-conducting characteristic function of the first section of the Zhiluo Formation aquifer; x and y are the location coordinates;

[0171] Calculate the comprehensive index of water conductivity characteristics of the aquifer in the coal seam roof based on HD(x,y), and draw a comprehensive zoning map of the water conductivity characteristics of the aquifer in the coal seam roof, such as... Figure 6 As shown;

[0172] Step 4: Calculate and plot the mining-induced failure index and its zoning map of the aquifer in the coal seam roof.

[0173] The Mining-Induced Failure Index (AMFI) for coal seam roofs is defined based on the differences in water conductivity between the caving zone and the water-conducting fracture zone, and between different strata within the water-conducting fracture zone. It comprehensively analyzes the spatial relationship between the aquifer, the caving zone, and the water-conducting fracture zone to calculate a quantitative value that comprehensively reflects the water conductivity of the aquifer after mining-induced damage. The index has a maximum value of 1 and a minimum value of 0. The maximum value is defined as the aquifer being completely located within the caving zone, and the minimum value is defined as the aquifer being completely located above the water-conducting fracture zone, unaffected by mining-induced damage. The calculation method is the ratio of the product of the thickness of each aquifer and the water conductivity of the water-conducting fracture zone at that aquifer to the total thickness of the aquifer. The water conductivity of the water-conducting fracture zone is defined as a piecewise function, where the caving zone is defined as 1, and the uppermost boundary of the fracture zone and above it is defined as 0. The decay function of the water conductivity of the strata within the fracture zone is linear. Therefore, the formula for calculating the mining-induced failure index of the aquifer is:

[0174]

[0175] in,

[0176] Where AMFI(x,y) is the mining-induced failure exponential function of the aquifer in the roof of the coal seam; h i f is the thickness of the i-th aquifer within the roof of the coal seam. (x,y) (h i Let be the water conductivity function of the i-th aquifer within the roof of the coal seam, where x and y are the position coordinates, and H is the water conductivity function. k H represents the height of the landslide zone. d The heights of the water-conducting fracture zone and the caving zone are calculated using empirical formulas or by analogy with measured data. After calculation, a zoning map is created using geographic information software. Figure 7 As shown.

[0177] Step 5: Overlay the comprehensive zoning map of the water-conducting characteristics of the aquifer on the roof of the coal seam with the zoning map of the mining-induced failure index of the aquifer on the roof of the coal seam to obtain the comprehensive zoning map of the water-filling intensity of the roof of the coal seam.

[0178] A comprehensive zoning map of the water-bearing intensity of the coal seam roof is obtained by superimposing the comprehensive zoning of the water-bearing characteristics of the aquifer in the coal seam roof with the zoning of the mining-induced failure index of the aquifer in the coal seam roof. The specific calculation formula is as follows:

[0179] FI=W3HD(x,y)+W4AMFI(x,y) Equation 6

[0180] In the formula: FI is the comprehensive index of water inflow intensity of the coal seam roof; W3 is the comprehensive zoning weight of the water-conducting characteristics of the aquifer in the coal seam roof; W4 is the zoning weight of the mining-induced damage index of the aquifer in the coal seam roof. The weight calculation method adopts common subjective and objective weight calculation methods. In this case, the analytic hierarchy process (AHP) was used to obtain the comprehensive zoning weights of the water-conducting characteristics of the aquifer in the coal seam roof and the mining-induced damage index of the aquifer in the coal seam roof as 0.83 and 0.17, respectively. The natural discontinuity zoning method built into ArcGIS software was used. The comprehensive zoning map of water inflow intensity of the coal seam roof is shown below. Figure 8 As shown.

Claims

1. A coupled evaluation method for the water-filling intensity of multiple aquifers in the roof of a coal seam, characterized in that, The specific steps are as follows: Step 1: Establish a database of the main controlling factors of water-conducting characteristics for each aquifer and evaluate the water-conducting characteristics of the corresponding aquifer to obtain a zoning map of the water-conducting characteristics of each aquifer. Step 2: Calculate the influence weight of each aquifer on the comprehensive zoning of the water-conducting characteristics of the aquifer in the coal seam roof, specifically as follows: Based on the permeability and porosity data of the study area, a fitting formula for the relationship between permeability and porosity in the study area was obtained: Formula 1 in, ρ is the permeability coefficient; a and m are constants, % . Porosity, % According to Equation 1, the specific value of parameter m is obtained; Then, according to Equation 1, the influence weight of aquifer i on the water-conducting characteristics of the aquifer in the coal roof is calculated using the following formula: Formula 2 In the formula, Let i be the weighting function for the comprehensive zoning of the water-conducting characteristics of the aquifer i on the top plate aquifer. Let i be a function of the thickness of the aquifer i. Let be the permeability coefficient function of aquifer i, L be the total number of aquifers, and m be a constant in Equation 1. x , y These are the position coordinates; Step 3: Based on the influence weights calculated in Step 2, superimpose the water-conducting characteristic zoning maps of each aquifer to obtain a comprehensive zoning map of the water-conducting characteristics of the aquifers in the coal seam roof. Step 4: Calculate and plot the mining-induced failure index and its zoning map of the aquifer in the coal seam roof, specifically as follows: The Mining-Induced Failure Index (AMFI) for coal seam roof aquifers is defined based on the differences in water conductivity between the caving zone and the water-conducting fracture zone, and between different strata within the water-conducting fracture zone. It comprehensively analyzes the spatial relationship between the aquifer, the caving zone, and the water-conducting fracture zone, calculating a quantitative value that comprehensively reflects the water conductivity of the aquifer after mining-induced damage. The maximum value is 1, and the minimum value is 0. The maximum value is defined as the aquifer being completely located within the caving zone, and the minimum value is defined as the aquifer being completely located above the water-conducting fracture zone, unaffected by mining-induced damage. The calculation method is the ratio of the product of the thickness of each aquifer and the water conductivity of the water-conducting fracture zone at that aquifer to the total thickness of the aquifer. The water conductivity of the water-conducting fracture zone is defined as a piecewise function, where the caving zone is defined as 1, and the uppermost boundary of the fracture zone and above it is defined as 0. The decay function of the water conductivity of the strata within the fracture zone is linear. Therefore, the formula for calculating the Mining-Induced Failure Index (AMFI) for coal seam roof aquifers is: Formula 4 in, Formula 5 in, AMFI ( x,y ) is the exponential function of mining-induced damage to the aquifer in the roof of the coal seam; The first in the roof of the coal seam i Aquifer thickness, The first in the roof of the coal seam i The hydraulic conductivity function of an aquifer, where x and y are the location coordinates. The height of the landslide zone, The height of the water-conducting fracture zone; After calculation according to Equations 4 and 5, a zoning map of the mining-induced damage index of the aquifer in the roof of the coal seam is drawn using geographic information software. Step 5: Overlay the comprehensive zoning map of the water-conducting characteristics of the aquifer on the roof of the coal seam with the zoning map of the mining-induced damage index of the aquifer on the roof of the coal seam to obtain the comprehensive zoning map of the water-filling intensity of the roof of the coal seam.

2. The coupled evaluation method for the water-filling intensity of multiple aquifers in the roof of a coal seam according to claim 1, characterized in that, Step 1 specifically involves: determining the main controlling factors of the water-conducting characteristics of each aquifer based on geological and hydrogeological data; quantifying and normalizing the main controlling factors of the water-conducting characteristics of the aquifer; establishing a database of the corresponding aquifers; calculating the weights of each main controlling factor of the corresponding aquifer; and then drawing a zoning map of the water-conducting characteristics of the corresponding aquifer based on the database of the corresponding aquifers and the weights of the main controlling factors. This is the evaluation result of the water-conducting characteristics of each aquifer.

3. The coupled evaluation method for the water-filling intensity of multiple aquifers in the roof of a coal seam according to claim 2, characterized in that, The main controlling factors of the water-conducting characteristics of each aquifer are multiple factors including aquifer thickness, permeability coefficient, unit inflow, sedimentary environment index, core recovery rate, tectonic development index, and aquifer mining damage index.

4. The coupled evaluation method for the water-filling intensity of multiple aquifers in the roof of a coal seam according to claim 3, characterized in that, ArcGIS software was used to draw the aquifer water-conducting feature zoning map in step 1.

5. The coupled evaluation method for the water-filling intensity of multiple aquifers in the roof of a coal seam according to claim 4, characterized in that, Step 3 specifically involves: Calculate the comprehensive index of water conductivity characteristics of the aquifer in the roof of the coal seam according to Equation 3: Formula 3 in, HD ( x,y ) is a comprehensive index function representing the water-conducting characteristics of the aquifer in the roof of the coal seam; Let i be the hydrodynamic characteristic function of aquifer i. x , y These are the position coordinates; according to HD ( x,y Calculate the comprehensive index of water-conducting characteristics of the aquifer in the roof of the coal seam, and draw a comprehensive zoning map of the water-conducting characteristics of the aquifer in the roof of the coal seam.

6. The coupled evaluation method for the water-filling intensity of multiple aquifers in the roof of a coal seam according to claim 5, characterized in that, Step 5 specifically involves: The comprehensive index FI of water-bearing intensity of multiple aquifers in the roof of a coal seam is calculated as follows: = Formula 6 in, The comprehensive index of water-conducting characteristics of aquifers in the roof of coal seams is assigned as the regional weight. The zoning weights for the mining-induced damage index of the aquifer in the coal seam roof; Based on the comprehensive index FI of water inflow intensity of multiple aquifers in the coal seam roof, the natural discontinuity zoning method built into ArcGIS software was used to zonate the coal seam roof and obtain a comprehensive zoning map of water inflow intensity.

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