Comprehensive evaluation method for zoning of water yield property of bottom sand layer of huge thick neonatal system

Abstract

The invention discloses a comprehensive evaluation method for zoning the water yield property of a bottom sand layer of a huge thick recent system, and particularly relates to the technical field of big data analysis. Comprising the steps of S01, coal seam region division, S02, sand layer water yield property data collection, S03, sand layer water yield property evaluation weight model construction, S04, sand layer water yield property data preprocessing, S05, sand layer water-bearing layer water yield property evaluation, S06, sand layer water-resisting layer stress risk monitoring, S07, coal seam mining safety analysis and S08, the method comprises the following steps: acquiring recent water yield characteristic data of each monitoring sub-region, calculating a water yield index of a water-bearing layer of a sand layer and a stress risk index of a water-resisting layer of the sand layer, analyzing to obtain a vulnerability evaluation coefficient of the sand layer, comparing and defining risk partitions, and analyzing geologic characteristics fitting reality to obtain a vulnerability evaluation result of the sand layer. The risk identification efficiency is improved, the state of the sand layer is monitored, and therefore early warning is given out.

Description

Technical Field

[0001] The present invention relates to the technical field of big data analysis, and more specifically, to a comprehensive evaluation method for the water-richness zoning of the extremely thick bottom sand layer of the Neogene System. Background Art

[0002] Coal-bearing sandstone aquifers are a very important underground water resource, which is closely related to people's production and life. However, due to the complex geological formation process and the influence of factors such as coal mining, there are certain difficulties in the development and utilization of coal-bearing sandstone aquifers. Therefore, it is particularly important to conduct a comprehensive prediction and evaluation of coal-bearing sandstone aquifers.

[0003] With the increase in the coal mining years, the mining of the thin bedrock area at the well field outcrop has been put on the agenda. The upper part of this area is formed by the interbedded deposition of clay layers and sand layers at the bottom of the Neogene System. The sand layer aquifers are generally developed and have medium water-richness. During the coal mining process, accurately grasping the water-richness zoning of the extremely thick bottom sand layer aquifer in the overlying strata is crucial for ensuring mining safety and reasonably formulating water control measures.

[0004] However, when it is actually used, there are still some disadvantages. For example, the extremely thick Neogene strata often have a complex stratum structure. In addition to sand layers, there may also be multiple layers of cohesive soil. The interaction and influence between different stratum structures will cause deviations in the evaluation of the water-richness of the sand layer. For the safe mining of boreholes in the extremely thick Neogene strata in the existing coal mining, the feedback mechanism of monitoring data is not perfect, and the coal mining construction area is not optimized and evaluated by fully combining the stratum characteristics, resulting in unstable borehole walls and increasing construction risks. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a comprehensive evaluation method for the water-richness zoning of the extremely thick bottom sand layer of the Neogene System, which is used to solve the problems proposed in the above-mentioned background art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A comprehensive evaluation method for the water-richness zoning of the extremely thick bottom sand layer of the Neogene System, including the following steps: Step S01: Coal seam area division: used to divide the area of the extremely thick bottom sand layer covering the coal seam into each monitoring sub-region according to the equal-area division method, and number each monitoring sub-region in the area of the extremely thick bottom sand layer of the Neogene System.

[0007] Step S02: Collection of water-richness data of the sand layer: used to collect the water-richness characteristic data of the Neogene System in each monitoring sub-region of the area of the extremely thick bottom sand layer of the Neogene System. The step S02: Collection of water-richness data of the sand layer includes a sub-step of collecting water-richness characteristic data of the sand layer and a sub-step of collecting water-resisting layer characteristic data of the sand layer.

[0008] Step S03: Construction of the weight model for evaluating the water-richness of the sand layer: Construct a comparison judgment matrix and calculate the weights of each data item.

[0009] Step S04: Preprocessing of the water-richness data of the sand layer: The Neogene water-richness characteristic data transmitted in the water-richness data collection step of the sand layer is standardized according to the conversion formula of normalization processing.

[0010] Step S05: Evaluation of the water-richness of the sand layer aquifer: According to the water-richness characteristic data of the sand layer collected in the water-richness characteristic data collection sub-step of the sand layer, calculate the water-richness index of the sand layer aquifer in each monitoring sub-region of the thick Neogene bottom sand layer area.

[0011] Step S06: Monitoring of the stress risk of the sand layer aquitard: According to the sand layer aquitard characteristic data collected in the sand layer aquitard characteristic data collection sub-step, calculate the stress risk index of the sand layer aquitard in each monitoring sub-region of the thick Neogene bottom sand layer area.

[0012] The said Step S07: Analysis of the safety of coal seam mining: Obtain the water-richness index of the sand layer aquifer and the stress risk index of the sand layer aquitard in each monitoring sub-region of the thick Neogene bottom sand layer area, and analyze to obtain the sand layer vulnerability evaluation coefficient in each monitoring sub-region of the thick Neogene bottom sand layer area.

[0013] The said Step S08: Evaluation of the safety of coal seam mining: Obtain the sand layer vulnerability evaluation coefficient in each monitoring sub-region of the thick Neogene bottom sand layer area, compare it with the zoning threshold of the sand layer vulnerability evaluation coefficient, and process it.

[0014] Preferably, the said Step S01: Coal seam area division is specifically as follows: Obtain the total area of the thick Neogene bottom sand layer area covering the coal seam, divide it into n monitoring sub-regions according to the equal-area division method, and sequentially number each monitoring sub-region of the thick Neogene bottom sand layer area as 1, 2,... i,... n.

[0015] Preferably, the said Step S02: Water-richness data collection of the sand layer is specifically as follows: Water-richness characteristic data collection sub-step: Collect the thickness of the Neogene bottom sand layer, the unit water inflow of the Neogene bottom sand layer, the water pressure of the Neogene bottom sand layer, and the cumulative thickness of the sand layer within 30 m upward from the Neogene bottom in each monitoring sub-region of the thick Neogene bottom sand layer area, and mark them as 、 、 、 ,where i = 1, 2,... n, and i represents the number of the i-th monitoring sub-region; Sub - steps for collecting characteristic data of the sand layer aquitard: Collect the Neogene thickness, the thickness of the clay layer at the bottom of the Neogene, and the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene in each monitoring sub - area of the extremely thick Neogene bottom sand layer area, and mark them as 、 、 。

[0016] Preferably, the step S03: Construction of the weight model for evaluating the water - rich property of the sand layer is specifically as follows: S41: Use the "10 / 10 18 / 2" scale method for scoring to construct a judgment matrix; S42: By calculating the geometric mean of each row of the judgment matrix and performing normalization processing, obtain the weights of each characteristic in the criterion layer; S43: Calculate the geometric mean of each row, divide each element by the sum of its row, and obtain the weights of each element in the evaluation layer; S44: Through the weights of each characteristic in the criterion layer and the weights of each element in the evaluation layer, obtain the weights of each data in the steps of collecting the water - rich property data of the sand layer.

[0017] Preferably, the step S04: Pretreatment of the water - rich property data of the sand layer is specifically as follows: S41: Substitute the original data: Neogene thickness, thickness of the sand layer at the bottom of the Neogene, specific yield of the sand layer at the bottom of the Neogene, water pressure of the sand layer at the bottom of the Neogene, and cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene into the conversion formula for normalization processing:

[0018] where, represents the standardized data of the i - th monitoring sub - area, represents the original data before standardization of the i - th monitoring sub - area, represents the maximum value of the original data before standardization of the i - th monitoring sub - area, represents the minimum value of the original data before standardization of the i - th monitoring sub - area; S42: Substitute the original data: thickness of the clay layer at the bottom of the Neogene and cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene into the conversion formula for normalization processing: 。

[0019] Preferably, the step S05: Evaluation of the water - rich property of the sand layer aquifer is specifically as follows: S61: Calculate the change rate of the sand layer thickness in each monitoring sub - area through the thickness of the sand layer at the bottom of the Neogene and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene:

[0020] Among them, represents the change rate of the sand layer thickness in the \(i\)-th monitored sub-region, represents the thickness of the bottom sand layer of the Neogene in the \(i\)-th monitored sub-region, represents the preset thickness of the bottom sand layer of the Neogene, represents the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene in the \(i\)-th monitored sub-region, represents the preset cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene, , respectively represent the weights of the thickness of the bottom sand layer of the Neogene and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene; S62: Calculate the water-richness of the sand layer in each monitored sub-region through the specific yield of the bottom sand layer of the Neogene and the water pressure of the bottom sand layer of the Neogene:

[0021] Among them, represents the water-richness of the sand layer in the \(i\)-th monitored sub-region, represents the specific yield of the bottom sand layer of the Neogene in the \(i\)-th monitored sub-region, represents the water pressure of the bottom sand layer of the Neogene in the \(i\)-th monitored sub-region, represents the density of water, , respectively represent the weights of the specific yield of the bottom sand layer of the Neogene and the water pressure of the bottom sand layer of the Neogene, and \(n\) represents the number of monitored sub-regions; S63: The calculation formula for the water-richness index of the sand layer aquifer is:

[0022] Among them, represents the water-richness index of the sand layer aquifer in the \(i\)-th monitored sub-region, represents the change rate of the sand layer thickness in the \(i\)-th monitored sub-region, represents the water-richness of the sand layer in the \(i\)-th monitored sub-region, \(e\) represents the natural constant, represents the mean value of the change rate of the sand layer thickness, represents the allowable difference between the change rate of the sand layer thickness and the mean value of the change rate of the sand layer thickness; Among them, .

[0023] Preferably, the step S06: Monitoring the stress risk of the sand layer aquitard is specifically: S71: Calculate the stress distribution degree of the clay layer in each monitored sub-region through the thickness of the Neogene and the thickness of the clay layer at the bottom of the Neogene:

[0024] Among them, represents the stress distribution degree of the clay layer in the $i$-th monitoring sub-region, represents the Neogene thickness in the $i$-th monitoring sub-region, represents the thickness of the clay layer at the bottom of the Neogene in the $i$-th monitoring sub-region, represents the water-proof performance coefficient of the clay layer, , respectively represent the weights of the Neogene thickness and the thickness of the clay layer at the bottom of the Neogene; Specifically, in each monitoring sub-region of the thick sand layer at the bottom of the Neogene, the water-proof performance coefficient of the clay layer can be obtained according to the physical and mechanical properties of the clay layer, referring to the laboratory test results or the empirical values under the geological conditions of the thick sand layer at the bottom of the Neogene; S72: From the formula: , the standard deviation of the stress distribution degree of the clay layer is obtained; Among them, represents the standard deviation of the stress distribution degree of the clay layer, represents the mean value of the stress distribution degree of the clay layer; S73: The calculation formula of the stress risk index of the sand aquiclude is:

[0025] Among them, represents the stress risk index of the sand aquiclude in the $i$-th monitoring sub-region, represents the stress distribution degree of the clay layer in the $i$-th monitoring sub-region, represents the Neogene thickness in the $i$-th monitoring sub-region, represents the thickness of the clay layer at the bottom of the Neogene in the $i$-th monitoring sub-region, represents the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene in the $i$-th monitoring sub-region, represents the standard deviation of the stress distribution degree of the clay layer, represents the weight of the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene.

[0026] Preferably, the calculation formula of the sand vulnerability evaluation coefficient is:

[0027] Among them, represents the sand vulnerability evaluation coefficient in the $i$-th monitoring sub-region, represents the water-richness index of the sand aquifer in the $i$-th monitoring sub-region, represents the stress risk index of the sand aquiclude in the $i$-th monitoring sub-region.

[0028] Preferably, the step S08: the safety assessment of coal seam mining is specifically as follows: Set the partition threshold , , obtain the sand layer vulnerability evaluation coefficient of each monitoring sub-region in the area of the thick Neogene bottom sand layer, and compare it with the partition threshold of the sand layer vulnerability evaluation coefficient. If , it indicates that the borehole in the thick Neogene strata in the coal seam construction area of this monitoring sub-region belongs to the relatively safe area. If , it indicates that the borehole in the thick Neogene strata in the coal seam construction area of this monitoring sub-region belongs to the relatively safer area. If , it indicates that the borehole in the thick Neogene strata in the coal seam construction area of this monitoring sub-region belongs to the vulnerable danger area The technical effects and advantages of the present invention: 1. The present invention provides a comprehensive evaluation method for the water-richness zoning of the thick Neogene bottom sand layer. By collecting the Neogene water-richness characteristic data of each monitoring sub-region in the area of the thick Neogene bottom sand layer, and according to the sand layer water-richness characteristic data collected in the sand layer water-richness characteristic data collection sub-step, calculate the water-richness index of the sand layer aquifer in each monitoring sub-region of the thick Neogene bottom sand layer area. Specifically, in each monitoring sub-region of the thick Neogene bottom sand layer area, the greater the thickness of the Neogene bottom sand layer, the unit water inflow of the Neogene bottom sand layer, the water pressure of the Neogene bottom sand layer, and the cumulative thickness of the sand layer within 30 m upward from the Neogene bottom, the more likely it is to cause the influencing factors of strong water-richness. According to the sand layer aquiclude characteristic data collected in the sand layer aquiclude characteristic data collection sub-step, calculate the stress risk index of the sand layer aquiclude in each monitoring sub-region of the thick Neogene bottom sand layer area. Specifically, in each monitoring sub-region of the thick Neogene bottom sand layer area, the greater the proportion of the thickness of the Neogene bottom clay layer in the Neogene thickness, the stronger the water isolation performance of the sand layer, resulting in an increase in the stress risk of the sand layer. The greater the proportion of the cumulative thickness of the clay layer within 30 m upward from the Neogene bottom in the Neogene thickness, the stronger the water isolation performance of the sand layer, resulting in an increase in the stress risk of the sand layer. Further analyze to obtain the sand layer vulnerability evaluation coefficient, and compare it with the partition threshold of the sand layer vulnerability evaluation coefficient. If , it indicates that the borehole in the thick Neogene strata in the coal seam construction area of this monitoring sub-region belongs to the relatively safe area. If , it indicates that the borehole in the thick Neogene strata in the coal seam construction area of this monitoring sub-region belongs to the relatively safer area, , it indicates that the borehole in the thick Neogene strata in the coal seam construction area of this monitoring sub-region belongs to the vulnerable danger area. By selecting the actual geological characteristics and comprehensively considering, it can more comprehensively and accurately evaluate the water-richness of the sand layer, avoid the one-sidedness of relying only on a single factor evaluation, improve the identification efficiency of the water-richness and the stress risk of the sand layer in each monitoring sub-region, realize the monitoring of the sand layer state, and thus send out early warning signals in time; 2. The present invention provides a comprehensive evaluation method for the water-richness zoning of the extremely thick bottom sand layer of the Neogene, which constructs a comparison judgment matrix, uses the "10 / 10 18 / 2" scaling method for scoring, constructs a judgment matrix, calculates the weights of each feature in the criterion layer, further calculates the weights of each data evaluation layer in the water-richness feature data collection sub-step of the sand layer and the weights of each data evaluation layer in the water-resistant layer feature data collection sub-step of the sand layer, and finally obtains the weights of each data in the water-richness data collection step of the sand layer according to the hierarchy. By using the analytic hierarchy process to construct a judgment matrix, the problems of analyzing the water-richness and water-resistant layer characteristics of the sand layer are decomposed into different levels, including the criterion layer and the data evaluation layer, etc., making the evaluation results more scientific and accurate, which is conducive to more accurately considering the contributions of various factors when evaluating the water-richness and water-resistant layer characteristics of the sand layer, thereby improving the accuracy of the evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic flow chart of a comprehensive evaluation method for the water-richness zoning of the extremely thick bottom sand layer of the Neogene according to the present invention.

[0030] Figure 2 It is a schematic structural diagram of step S02: water-richness data collection of the sand layer according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] Please refer to Figure 1 As shown, the present invention provides a comprehensive evaluation method for the water-richness zoning of the extremely thick bottom sand layer of the Neogene, including the following steps: Step S01: Coal seam area division: used to divide the area of the extremely thick bottom sand layer covering the coal seam into each monitoring sub-area according to an equal-area division method, and number each monitoring sub-area of the extremely thick bottom sand layer area.

[0033] In a possible design, step S01: Coal seam area division is specifically: Obtain the total area of the extremely thick bottom sand layer area covering the coal seam, divide it into n monitoring sub-areas according to an equal-area division method, and sequentially number each monitoring sub-area of the extremely thick bottom sand layer area as 1, 2,... i,... n.

[0034] Please refer to Figure 2As shown, the step S02: Collection of water-richness data of sand layer: It is used to collect the water-richness characteristic data of the Neogene in each monitoring sub-region of the thick bottom sand layer of the Neogene. The step S02: Collection of water-richness data of sand layer includes a sub-step of collecting water-richness characteristic data of sand layer and a sub-step of collecting water-resisting layer characteristic data of sand layer. The water-richness characteristic data of the Neogene include water-richness characteristic data of sand layer and water-resisting layer characteristic data of sand layer.

[0035] In a possible design, the step S02: Collection of water-richness data of sand layer is specifically as follows: Sub-step of collecting water-richness characteristic data of sand layer: Collect the thickness of the bottom sand layer of the Neogene, the specific yield of the bottom sand layer of the Neogene, the water pressure of the bottom sand layer of the Neogene, and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene in each monitoring sub-region of the thick bottom sand layer of the Neogene, and mark them as , , , , where i = 1, 2,... n, and i represents the number of the i-th monitoring sub-region; Sub-step of collecting water-resisting layer characteristic data of sand layer: Collect the thickness of the Neogene, the thickness of the clay layer at the bottom of the Neogene, and the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene in each monitoring sub-region of the thick bottom sand layer of the Neogene, and mark them as , , .

[0036] The step S03: Construction of water-richness evaluation weight model of sand layer: It is used to receive the water-richness characteristic data of the Neogene transmitted by the step S02: Collection of water-richness data of sand layer, construct a comparison judgment matrix, and calculate the weights of each data.

[0037] In a possible design, the step S03: Construction of water-richness evaluation weight model of sand layer is specifically as follows: S31: Use the "10 / 10 18 / 2" scale method to score and construct a judgment matrix; S32: By calculating the geometric mean of each row of the judgment matrix and performing normalization processing, obtain the weights of each feature in the criterion layer; S33: Calculate the geometric mean of each row, divide each element by the sum of its row, and obtain the weights of each element in the evaluation layer; S34: Through the weights of each feature in the criterion layer and the weights of each element in the evaluation layer, obtain the weights of each data in the step of collecting water-richness data of sand layer.

[0038] In this embodiment, it should be specifically noted that the step S03: Construction of water-richness evaluation weight model of sand layer is specifically as follows: S001: Table 1 "10 / 10 18 / 2” scale

[0039] S002: Calculate the weights of the criterion layer: Construct a comparison judgment matrix as shown in Table 2: Table 2 Judgment matrix Through Calculate the geometric mean of each row: Among them, is the element in the q-th row and j-th column of the judgment matrix, and m is the order of the matrix; Row 1: (10 / 10 + 3 / 17 + 5 / 15)^(1 / 3) = 0.38891111873282, Row 2: (17 / 3 + 10 / 10 + 16 / 4)^(1 / 3) = 2.83006158292518, Row 3: (5 / 15 + 4 / 16 + 10 / 10)^(1 / 3) = 0.90856029641607; Normalize the matrix and calculate the weights of the criterion layer: Feature 1: 0.3889 / (0.3889 + 2.83 + 0.9086) ≈ 0.0942, Feature 2: 2.83 / (0.3889 + 2.83 + 0.9086) ≈ 0.6857, Feature 3: 0.9086 / (0.3889 + 2.83 + 0.9086) ≈ 0.2201; S003: The calculation steps for the weights of each data evaluation layer of the sand layer water-richness characteristic data acquisition sub-step are as follows: Construct a comparison judgment matrix as shown in Table 3: Table 3 Judgment matrix Through Calculate the geometric mean of each row: Row 1: (10 / 10 + 5 / 15 + 6 / 14 + 11 / 9)^(1 / 4) = 0.64641739380889, Row 2: (15 / 5 + 10 / 10 + 9 / 11 + 12 / 8)^(1 / 4) = 1.38520989283231, Row 3: (14 / 6 + 11 / 9 + 10 / 10 + 9 / 11)^(1 / 4) = 1.23593091702245, Row 4: (9 / 11 + 8 / 12 + 11 / 9 + 10 / 10)^(1 / 4) = 0.90360200360985; Normalize the matrix and calculate the weights of the evaluation layer: Calculate the weights of the evaluation layer for the thickness of the bottom sand layer of the Neogene: 0.6464 / (0.6464 + 1.3852 + 1.2359 + 0.9036) ≈ 0.1550, Calculate the weights of the evaluation layer for the specific yield of the bottom sand layer of the Neogene: 1.3852 / (0.6464 + 1.3852 + 1.2359 + 0.9036) ≈ 0.3321, Calculate the weights of the evaluation layer for the water pressure of the bottom sand layer of the Neogene: 1.2359 / (0.6464 + 1.3852 + 1.2359 + 0.9036) ≈ 0.2963, Calculate the weights of the evaluation layer for the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene: 0.9036 / (0.6464 + 1.3852 + 1.2359 + 0.9036) ≈ 0.2166; S004: The calculation steps for the weights of each data evaluation layer in the sand layer aquiclude feature data acquisition sub-step are as follows: Construct a comparison judgment matrix as shown in Table 4: Table 4 Judgment matrix The calculation steps are the same as above; S005: The weights of each data: Construct a comparison judgment matrix as shown in Table 5: Table 5 Judgment matrix

[0040] Step S04: Pretreatment of sand layer water-richness data: It is used to perform standardization processing on the Neogene water-richness characteristic data transmitted in the sand layer water-richness data acquisition step according to the conversion formula of normalization processing.

[0041] In a possible design, step S04: The pretreatment of sand layer water-richness data is specifically as follows: S41: Substitute the original data: the thickness of the Neogene, the thickness of the bottom sand layer of the Neogene, the specific yield of the bottom sand layer of the Neogene, the water pressure of the bottom sand layer of the Neogene, and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene into the conversion formula of normalization processing:

[0042] Among them, Data after standardization for the \(i\)-th monitored sub-region, Original data before standardization for the \(i\)-th monitored sub-region, Maximum value of the original data before standardization for the \(i\)-th monitored sub-region, Minimum value of the original data before standardization for the \(i\)-th monitored sub-region; S42: Substitute the original data: the thickness of the clay layer at the bottom of the Neogene and the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene into the conversion formula for normalization processing: .

[0043] The step S05: Evaluation of the water-richness of the sand layer aquifer: is used to receive the Neogene water-richness characteristic data of the step S02: Collection and transmission of sand layer water-richness data, and calculate the water-richness index of the sand layer aquifer for each monitored sub-region in the thick Neogene bottom sand layer area according to the sand layer water-richness characteristic data collected in the sand layer water-richness characteristic data collection sub-step.

[0044] In a possible design, the step S05: Evaluation of the water-richness of the sand layer aquifer is specifically: S51: Calculate the change rate of the sand layer thickness for each monitored sub-region through the thickness of the sand layer at the bottom of the Neogene and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene:

[0045] Where, Represents the change rate of the sand layer thickness for the \(i\)-th monitored sub-region, Represents the thickness of the sand layer at the bottom of the Neogene for the \(i\)-th monitored sub-region, Represents the preset thickness of the sand layer at the bottom of the Neogene, Represents the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene for the \(i\)-th monitored sub-region, Represents the preset cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene, , Respectively represent the weights of the thickness of the sand layer at the bottom of the Neogene and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene; S52: Calculate the water-richness of the sand layer for each monitored sub-region through the specific yield of the sand layer at the bottom of the Neogene and the water pressure of the sand layer at the bottom of the Neogene:

[0046] Where, Represents the water-richness of the sand layer for the \(i\)-th monitored sub-region, Represents the specific yield of the sand layer at the bottom of the Neogene for the \(i\)-th monitored sub-region, Represents the water pressure of the sand layer at the bottom of the Neogene for the \(i\)-th monitored sub-region, is expressed as the density of water, and are respectively expressed as the weight of the specific yield of the bottom sand layer of the Neogene and the water pressure of the bottom sand layer of the Neogene, and n represents the number of monitoring sub-regions; S53: The calculation formula for the water-richness index of the sand layer aquifer is:

[0047] wherein, is expressed as the water-richness index of the sand layer aquifer in the i-th monitoring sub-region, is expressed as the change rate of the sand layer thickness in the i-th monitoring sub-region, is expressed as the water-richness of the sand layer in the i-th monitoring sub-region, and e represents the natural constant, is expressed as the average value of the change rate of the sand layer thickness, is expressed as the allowable difference between the change rate of the sand layer thickness and the average value of the change rate of the sand layer thickness; wherein, .

[0048] Specifically, in each monitoring sub-region of the thick bottom sand layer of the Neogene, the greater the thickness of the bottom sand layer of the Neogene, the specific yield of the bottom sand layer of the Neogene, the water pressure of the bottom sand layer of the Neogene, and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene, the more likely it is to cause factors with strong water-richness.

[0049] The step S06: Monitoring the stress risk of the sand layer aquitard: is used to receive the Neogene water-richness characteristic data collected and transmitted in the step S02: Data acquisition and transmission of the water-richness of the sand layer, and calculate the stress risk index of the sand layer aquitard in each monitoring sub-region of the thick bottom sand layer of the Neogene according to the sand layer aquitard characteristic data collected by the sand layer aquitard characteristic data acquisition sub-step.

[0050] In a possible design, the step S06: Monitoring the stress risk of the sand layer aquitard is specifically: S61: Calculate the stress distribution degree of the clay layer in each monitoring sub-region through the thickness of the Neogene and the thickness of the clay layer at the bottom of the Neogene:

[0051] wherein, is expressed as the stress distribution degree of the clay layer in the i-th monitoring sub-region, is expressed as the thickness of the Neogene in the i-th monitoring sub-region, is expressed as the thickness of the clay layer at the bottom of the Neogene in the i-th monitoring sub-region, is expressed as the coefficient of water isolation performance of the clay layer, and are respectively expressed as the weights of the thickness of the Neogene and the thickness of the clay layer at the bottom of the Neogene; Specifically, in each monitoring sub-region of the extremely thick bottom sand layer area of the Neogene, the coefficient of water isolation performance of the clay layer can be obtained based on the physical and mechanical properties of the clay layer, referring to the laboratory test results or the empirical values under the geological conditions of the extremely thick bottom sand layer of the Neogene. S62: From the formula: , the standard deviation of the stress distribution degree of the clay layer is obtained. Wherein, represents the standard deviation of the stress distribution degree of the clay layer, represents the mean value of the stress distribution degree of the clay layer; S63: The calculation formula for the stress risk index of the sand layer aquiclude is:

[0052] Wherein, represents the stress risk index of the sand layer aquiclude in the i-th monitoring sub-region, represents the stress distribution degree of the clay layer in the i-th monitoring sub-region, represents the thickness of the Neogene in the i-th monitoring sub-region, represents the thickness of the bottom clay layer of the Neogene in the i-th monitoring sub-region, represents the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene in the i-th monitoring sub-region, represents the standard deviation of the stress distribution degree of the clay layer, represents the weight of the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene.

[0053] Specifically, in each monitoring sub-region of the extremely thick bottom sand layer area of the Neogene, the larger the proportion of the thickness of the bottom clay layer of the Neogene to the thickness of the Neogene, the stronger the water isolation performance of the sand layer, resulting in an increase in the stress risk of the sand layer. The larger the proportion of the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene to the thickness of the Neogene, the stronger the water isolation performance of the sand layer, resulting in an increase in the stress risk of the sand layer.

[0054] Step S07: Coal seam mining safety analysis: Obtain the water-richness index of the sand layer aquifer and the stress risk index of the sand layer aquiclude in each monitoring sub-region of the extremely thick bottom sand layer area of the Neogene, and analyze to obtain the sand layer vulnerability evaluation coefficient in each monitoring sub-region of the extremely thick bottom sand layer area of the Neogene.

[0055] In a possible design, the calculation formula for the sand layer vulnerability evaluation coefficient is:

[0056] Wherein, represents the sand layer vulnerability evaluation coefficient in the i-th monitoring sub-region, represents the water-richness index of the sand layer aquifer in the i-th monitoring sub-region, Denote the stress risk index of the sand aquitard for the \(i\)-th monitored sub-region.

[0057] Specifically, in each monitored sub-region of the thick Neogene bottom sand layer area, the thickness of the Neogene bottom clay layer and the cumulative thickness of the clay layer within 30 m upward from the Neogene bottom are negatively correlated with the sand layer vulnerability evaluation coefficient.

[0058] Step S08: Coal seam mining safety assessment: Obtain the sand layer vulnerability evaluation coefficients of each monitored sub-region in the thick Neogene bottom sand layer area, compare them with the partition thresholds of the sand layer vulnerability evaluation coefficients, and process them.

[0059] In a possible design, step S08: Coal seam mining safety assessment is specifically: Set partition thresholds 、 , obtain the sand layer vulnerability evaluation coefficients of each monitored sub-region in the thick Neogene bottom sand layer area, compare them with the partition thresholds of the sand layer vulnerability evaluation coefficients. If , it indicates that the boreholes in the thick Neogene strata of the coal seam construction area in this monitored sub-region belong to the relatively safe area. If , it indicates that the boreholes in the thick Neogene strata of the coal seam construction area in this monitored sub-region belong to the relatively safer area. If , it indicates that the boreholes in the thick Neogene strata of the coal seam construction area in this monitored sub-region belong to the vulnerable and dangerous area.

[0060] In this embodiment, it should be specifically noted that the present invention calculates the water-richness index of the sand aquifer in each monitored sub-region of the thick Neogene bottom sand layer area by collecting the water-richness characteristic data of the Neogene in each monitored sub-region of the thick Neogene bottom sand layer area. Specifically, in each monitored sub-region of the thick Neogene bottom sand layer area, the greater the thickness of the Neogene bottom sand layer, the unit water inflow of the Neogene bottom sand layer, the water pressure of the Neogene bottom sand layer, and the cumulative thickness of the sand layer within 30 m upward from the Neogene bottom, the more likely it is to cause factors with strong water-richness. According to the sand aquitard characteristic data collected in the sand aquitard characteristic data collection sub-step, the stress risk index of the sand aquitard in each monitored sub-region of the thick Neogene bottom sand layer area is calculated. Specifically, in each monitored sub-region of the thick Neogene bottom sand layer area, the greater the proportion of the thickness of the Neogene bottom clay layer in the Neogene thickness, the stronger the water isolation performance of the sand layer, resulting in an increase in the stress risk of the sand layer. The greater the proportion of the cumulative thickness of the clay layer within 30 m upward from the Neogene bottom in the Neogene thickness, the stronger the water isolation performance of the sand layer, resulting in an increase in the stress risk of the sand layer. Further analysis yields the sand layer vulnerability evaluation coefficient, which is compared with the partition threshold of the sand layer vulnerability evaluation coefficient. If , indicating that the boreholes in the extremely thick Neogene strata in the coal seam construction area of this monitoring sub-region belong to the relatively safe area. If , indicating that the boreholes in the extremely thick Neogene strata in the coal seam construction area of this monitoring sub-region belong to the relatively safer area. If , indicating that the boreholes in the extremely thick Neogene strata in the coal seam construction area of this monitoring sub-region belong to the vulnerable and dangerous area. By selecting actual geological features and comprehensively considering, the water-richness of the sand layer can be evaluated more comprehensively and accurately, avoiding the one-sidedness of relying only on a single factor for evaluation, improving the efficiency of identifying the water-richness of the sand layer and the stress risk of the sand layer in each monitoring sub-region, realizing the monitoring of the sand layer state, and thus sending out early warning signals in a timely manner.

[0061] The present invention constructs a comparative judgment matrix, uses the "10 / 10 18 / 2" scaling method for scoring, constructs a judgment matrix, calculates the weights of each feature in the criterion layer, further calculates the weights of each data evaluation layer in the sub-step of data acquisition for the water-richness characteristics of the sand layer and the weights of each data evaluation layer in the sub-step of data acquisition for the characteristics of the sand layer's water-resisting layer, and finally obtains the weights of each data in the data acquisition step of the water-richness of the sand layer according to the hierarchy. By using the analytic hierarchy process to construct a judgment matrix, the problem of analyzing the water-richness and the characteristics of the water-resisting layer of the sand layer is decomposed into different levels, including the criterion layer and the data evaluation layer, etc., making the evaluation result more scientific and accurate, which is conducive to more accurately considering the contributions of various factors when evaluating the water-richness and the characteristics of the water-resisting layer of the sand layer, thereby improving the accuracy of the evaluation.

[0062] Finally: The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A comprehensive evaluation method for the water-richness zoning of extremely thick Neogene bottom sand layers, characterized in that, Including: Step S01: Coal seam area division: used to divide the area of the thick Neogene bottom sand layer covering the coal seam into each monitoring sub-region according to the equal-area division method, and number each monitoring sub-region of the thick Neogene bottom sand layer area; Step S02: Collection of water-richness data of the sand layer: used to collect the water-richness characteristic data of the Neogene in each monitoring sub-region of the thick Neogene bottom sand layer area. The said Step S02: Collection of water-richness data of the sand layer includes a sub-step of collecting water-richness characteristic data of the sand layer and a sub-step of collecting water-resisting layer characteristic data of the sand layer; Step S03: Construction of a water-richness evaluation weight model for the sand layer: construct a comparison judgment matrix and calculate the weights of each data; Step S04: Pretreatment of water-richness data of the sand layer: used to perform standardized processing on the water-richness characteristic data of the Neogene transmitted in the step of collecting water-richness data of the sand layer according to the conversion formula of normalization processing; Step S05: Evaluation of water-richness of the sand aquifer: used to calculate the water-richness index of the sand aquifer in each monitoring sub-region of the thick Neogene bottom sand layer area; Step S06: Monitoring of the stress risk of the sand water-resisting layer: used to calculate the stress risk index of the sand water-resisting layer in each monitoring sub-region of the thick Neogene bottom sand layer area; The said Step S07: Analysis of the safety of coal seam mining: obtain the water-richness index of the sand aquifer and the stress risk index of the sand water-resisting layer in each monitoring sub-region of the thick Neogene bottom sand layer area, and analyze to obtain the sand vulnerability evaluation coefficient in each monitoring sub-region of the thick Neogene bottom sand layer area; The said Step S08: Evaluation of the safety of coal seam mining: obtain the sand vulnerability evaluation coefficient in each monitoring sub-region of the thick Neogene bottom sand layer area, compare it with the partition threshold of the sand vulnerability evaluation coefficient, and process it.

2. The comprehensive evaluation method for the water-richness zoning of the extremely thick Neogene bottom sand layer according to claim 1, characterized in that: The said Step S01: The coal seam area division is specifically as follows: Obtain the total area of the thick Neogene bottom sand layer area covering the coal seam, divide it into n monitoring sub-regions according to the equal-area division method, and sequentially number each monitoring sub-region of the thick Neogene bottom sand layer area as 1, 2,... i,... n.

3. The comprehensive evaluation method for the water-richness zoning of the extremely thick bottom sand layer of the Neogene according to claim 1, characterized in that: The said Step S02: The collection of water-richness data of the sand layer is specifically as follows: Sub - steps for collecting water - rich characteristics data of sand layers: Collect the thickness of the bottom sand layer of the Neogene System, the specific yield of the bottom sand layer of the Neogene System, the water pressure of the bottom sand layer of the Neogene System, and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene System in each monitoring sub - area of the area with a very thick bottom sand layer of the Neogene System, and mark them respectively as , , , , where \(i = 1,2,\cdots,n\), and \(i\) represents the number of the \(i\) - th monitoring sub - area; Sub-steps for collecting characteristic data of the sand aquiclude: Collect the Neogene thickness, the thickness of the clay layer at the bottom of the Neogene, and the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene in each monitoring sub-region of the area with extremely thick Neogene bottom sand layer, and mark them as , , .

4. The comprehensive evaluation method for the water-richness zoning of the extremely thick Neogene bottom sand layer according to claim 1, wherein: The said Step S03: The construction of the water-richness evaluation weight model for the sand layer is specifically as follows: S41: Use the "10 / 10 18 / 2" scale method for scoring and construct a judgment matrix; S42: By calculating the geometric mean of each row of the judgment matrix and performing normalization processing, obtain the weights of each characteristic of the criterion layer; S43: Calculate the geometric mean of each row, divide each element by the sum of its row, and obtain the weights of each element of the evaluation layer; S44: Through the weights of each characteristic of the criterion layer and the weights of each element of the evaluation layer, obtain the weights of each data in the step of collecting water-richness data of the sand layer.

5. The comprehensive evaluation method for water-richness zoning of extremely thick Neogene bottom sand layers according to claim 1, characterized in that: The said Step S04: The pretreatment of water-richness data of the sand layer is specifically as follows: S41: Substitute the original data: Neogene thickness, thickness of the bottom sand layer of the Neogene, unit water inflow of the bottom sand layer of the Neogene, water pressure of the bottom sand layer of the Neogene, and cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene into the conversion formula of normalization processing; Among them, represents the standardized data of the i-th monitoring sub-region, represents the original data before standardization of the i-th monitoring sub-region, represents the maximum value of the original data before standardization of the i-th monitoring sub-region, represents the minimum value of the original data before standardization of the i-th monitoring sub-region; S42: Substitute the original data: thickness of the clay layer at the bottom of the Neogene and cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene into the conversion formula of normalization processing; 。 6. The comprehensive evaluation method for water-richness zoning of extremely thick Neogene bottom sand layers according to claim 1, characterized in that: The specific content of step S05: Evaluation of the water-richness of the sand aquifer is as follows: S61: Calculate the change rate of the sand layer thickness of each monitoring sub-region through the thickness of the bottom sand layer of the Neogene and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene. Among them, represents the change rate of the sand layer thickness in the $i$-th monitoring sub-region, represents the thickness of the bottom sand layer of the Neogene in the $i$-th monitoring sub-region, represents the preset thickness of the bottom sand layer of the Neogene, represents the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene in the $i$-th monitoring sub-region, represents the preset cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene, and respectively represent the weights of the thickness of the bottom sand layer of the Neogene and the cumulative thickness of the sand layer within 30 m upward from the bottom of the Neogene; S62: Calculate the water-richness of the sand layer of each monitoring sub-region through the specific yield of the bottom sand layer of the Neogene and the water pressure of the bottom sand layer of the Neogene. Among them, represents the water-richness of the sand layer in the $i$-th monitoring sub-region, represents the specific yield of the bottom sand layer of the Neogene in the $i$-th monitoring sub-region, represents the water pressure of the bottom sand layer of the Neogene in the $i$-th monitoring sub-region, represents the density of water, 、 respectively represent the weights of the specific yield of the bottom sand layer of the Neogene and the water pressure of the bottom sand layer of the Neogene, and $n$ represents the number of monitoring sub-regions; S63: The calculation formula for the water-richness index of the sand aquifer is as follows: Among them, represents the water-richness index of the sand aquifer in the i-th monitoring sub-region, represents the sand layer thickness change rate in the i-th monitoring sub-region, represents the water-richness of the sand layer in the i-th monitoring sub-region, and e represents the natural constant, represents the average value of the sand layer thickness change rate, represents the allowable difference between the sand layer thickness change rate and the average value of the sand layer thickness change rate; Among them, .

7. The comprehensive evaluation method for the water-richness zoning of the extremely thick Neogene bottom sand layer according to claim 1, characterized in that: The specific content of step S06: Monitoring of the stress risk of the sand aquitard is as follows: S71: Calculate the stress distribution degree of the clay layer of each monitoring sub-region through the thickness of the Neogene and the thickness of the clay layer at the bottom of the Neogene. Among them, represents the stress distribution degree of the clay layer in the $i$-th monitoring sub-region, represents the Neogene thickness in the $i$-th monitoring sub-region, represents the thickness of the clay layer at the bottom of the Neogene in the $i$-th monitoring sub-region, represents the coefficient of water isolation performance of the clay layer, and respectively represent the weights of the Neogene thickness and the thickness of the clay layer at the bottom of the Neogene; Specifically, in each monitoring sub-region of the thick bottom sand layer of the Neogene, the water-resisting performance coefficient of the clay layer can be obtained according to the physical and mechanical properties of the clay layer, referring to the laboratory test results or the empirical values under the geological conditions of the thick bottom sand layer of the Neogene. S72: From the formula: , the standard deviation of the stress distribution degree of the clay layer is obtained; Among them, represents the standard deviation of the stress distribution degree of the clay layer, represents the mean value of the stress distribution degree of the clay layer; S73: The calculation formula for the stress risk index of the sand aquitard is as follows: Among them, represents the stress risk index of the sandy aquitard in the $i$-th monitoring sub-region, represents the stress distribution degree of the clay layer in the $i$-th monitoring sub-region, represents the thickness of the Neogene in the $i$-th monitoring sub-region, represents the thickness of the clay layer at the bottom of the Neogene in the $i$-th monitoring sub-region, represents the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene in the $i$-th monitoring sub-region, represents the standard deviation of the stress distribution degree of the clay layer, represents the weight of the cumulative thickness of the clay layer within 30 m upward from the bottom of the Neogene.

8. The comprehensive evaluation method for the water-richness zoning of the extremely thick Neogene bottom sand layer according to claim 1, characterized in that: The calculation formula for the vulnerability evaluation coefficient of the sand layer is as follows: Among them, represents the evaluation coefficient of the sand layer vulnerability in the i-th monitoring sub-region, represents the water-richness index of the sand layer aquifer in the i-th monitoring sub-region, represents the stress risk index of the sand layer aquitard in the i-th monitoring sub-region.

9. The comprehensive evaluation method for the water-richness zoning of the extremely thick Neogene bottom sand layer according to claim 1, characterized in that: The specific content of step S08: Evaluation of the safety of coal seam mining is as follows: Set partition threshold and , obtain the sand layer vulnerability evaluation coefficients of each monitoring sub - region in the area of the extremely thick Neogene bottom sand layer, and compare them with the partition thresholds of the sand layer vulnerability evaluation coefficients. If , it indicates that the boreholes in the extremely thick Neogene strata of the coal seam construction area in this monitoring sub - region belong to the relatively safe area. If , it indicates that the boreholes in the extremely thick Neogene strata of the coal seam construction area in this monitoring sub - region belong to the relatively safer area. If , it indicates that the boreholes in the extremely thick Neogene strata of the coal seam construction area in this monitoring sub - region belong to the vulnerable danger area.

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