A Quantitative Identification Method for Mixed Water Sources and Mixing Degrees of Mine Water Inflows from Multiple Aquifers

Abstract

The present invention relates to the technical field of mine, and discloses a method for quantitatively identifying the mixed water sources and the mixing degree of mine water inflow in multiple aquifers. The method includes the following steps: S1. Collect and collate the hydrogeochemical components of groundwater in multiple aquifers during the mine production period; S2. Analyze the basic characteristics of the hydrogeochemical components of groundwater in the mine with multiple aquifers by using mathematical statistics method, and determine the typical water samples of groundwater in the mine with multiple aquifers; S3. Select the hydrogeochemical components with stable chemical properties as the variables of the identification model for the mixed water sources of mine water inflow in multiple aquifers, identify the recharge sources of the mixed water sources, and calculate the mixing ratio; S4. Based on the PHREEQC mixing simulation, quantitatively identify the influence of the mixing degree on the water chemistry of the mixed water sources. The method proposed by the present invention is simple, easy to operate, economical and reliable, and can guide the water control work in mines with multiple aquifers in production practice. It has important guiding significance for judging the hydraulic connection and the direction of hydrochemical evolution in multiple aquifers.

Description

Technical Field

[0001] The present invention relates to the technical field of mine, and particularly relates to a method for quantitatively identifying the mixed water sources and the mixing degree of mine water inflow in multi-aquifer mines. Background Art

[0002] The hydrogeological conditions of mines in China are extremely complex, and coal resources and groundwater are usually in a coupled state. When coal is mined, it is bound to strengthen the hydraulic connection of multi-aquifers and intensify the mixing effect, resulting in the diversification of the hydrochemical types of mine groundwater. It has an adverse impact on the identification of mine water inflow sources and the reasonable development and protection of groundwater resources. Therefore, quantitatively identifying the mixed water sources and the mixing degree of mine water inflow in multi-aquifer mines is helpful for mine production in the following aspects: 1. Clarify the recharge relationship of multi-aquifers in mine groundwater; 2. Accurately identify the mixing ratio of multi-aquifers contributing to the mixed water source; 3. Quantify the mixing degree of the mixed water source of water inflow, invert the runoff path of the mixed water source of water inflow and the mineral composition of the rocks passed through; 4. Scientifically and reasonably protect the groundwater resources of mines.

[0003] At present, the identification methods of the mixed water sources of mine water inflow in multi-aquifer mines mainly include hydrochemical graphical method, principal component analysis method, hydrogeochemical numerical simulation method, etc. When studying the mixed water sources and the mixing degree of mine water inflow in the past, other effects on the runoff path of the mixed water source were often ignored, resulting in a large calculation error of the mixing ratio of the mixed water source of mine water inflow, unable to correctly understand the recharge relationship between multi-aquifers, and interfering with the accurate identification of the mixed water source of mine water inflow. Summary of the Invention

[0004] To solve the technical problems proposed in the background art, the present invention provides a method for quantitatively identifying the mixed water sources and the mixing degree of mine water inflow in multi-aquifer mines.

[0005] The present invention is realized by adopting the following technical solutions: A method for quantitatively identifying the mixed water sources and the mixing degree of mine water inflow in multi-aquifer mines, the method comprising the following steps:

[0006] S1. Collect and collate the hydrogeochemical components of groundwater in multi-aquifers during mine production;

[0007] In this solution, in the step S1, the hydrogeochemical components are obtained by collecting water samples flowing from underground drainage holes or water outlets during mine production and sealing and testing them, including but not limited to comprehensive indicators, conventional hydrochemistry, isotopes, and trace elements.

[0008] In this solution, in the step S1, the multi-aquifer mine from top to bottom is successively the bottom aquifer of the loose layer - bottom aquifer, the sandstone fissure aquifer of the Permian coal series - coal series, the karst fissure aquifer of the Taiyuan Formation of the Carboniferous - Taihui, and the karst fissure aquifer of the Ordovician - Aohui.

[0009] S2. Analyze the basic characteristics of the hydrogeochemical components of the groundwater in a multi-aquifer mine using mathematical statistics, and determine the typical water samples of the groundwater in the multi-aquifer mine.

[0010] In this solution, in step S2, the basic characteristics of the hydrogeochemical components of the multi-aquifer mine are determined using mathematical statistics, and the basic characteristics include but are not limited to the maximum value, minimum value, mean value, and standard deviation.

[0011] S3. Select the hydrogeochemical components with stable chemical properties as the variables of the mixed water source identification model for the water inrush from the multi-aquifer mine, identify the recharge sources of the mixed water source, and calculate the mixing ratio.

[0012] Furthermore, in step S3, based on the hydrogeochemical theory, select the hydrogeochemical components with stable chemical properties (Cl - , δD, and δ 18 O) as the variables of the mixed water source identification model.

[0013] Furthermore, in step S3, based on the mean value and standard deviation of Cl - , δD, and δ 18 O, standardize the variables of the multi-endmember mixing pattern identification model, and at the same time calculate the weights of the three variables using the entropy weight method.

[0014] Furthermore, in step S3, the mixed endmember is determined according to the following method: First, use Origin to draw the spatial scatter plot of the standardized Cl - , δD, and δ 18 O variables, and then determine the relationship between the mixed water sample S and the tetrahedron ABCD. The tetrahedron ABCD is a tetrahedron composed of four typical water samples, namely the bottom aquifer, coal measures, Taiyuan limestone, and Ordovician limestone water samples. And assume that the four corner points of the tetrahedron ABCD correspond to four faces ΠA, ΠB, ΠC, and ΠD respectively, and the corresponding normal vectors are and (define the normal vector as positive outside the tetrahedron), A x , B x , C x , D x are any points on the four faces, and P is any point in space. Then the spatial vectors are and And judge the mixing degree according to the following method;

[0015] If both are less than zero at the same time, then point P is inside the tetrahedron ABCD, indicating that the mixed water sample receives recharge from four aquifers;

[0016] When is greater than zero, If it is less than zero, then point P is located inside the pentahedron ACDA 1 C 1 D 1 inside, indicating that the mixed water sample P does not receive recharge from the aquifer represented by B;

[0017] When is greater than zero, is less than zero, that is, point P is located inside the pentahedron CC1C2DD1D2, indicating that the mixed water sample P does not receive recharge from the aquifers represented by A and B;

[0018] is greater than zero, is less than zero, representing that the mixed water sample P does not receive recharge from the aquifers represented by A, B, and C, that is, the mixing effect received is weak.

[0019] Furthermore, in step S3, according to the number of recharge end-members of the mixed water source, the corresponding mixing ratio calculation models of four-end-member, three-end-member, and two-end-member are constructed respectively. And to ensure the accuracy of the model, the weights need to be calculated based on the entropy weight method before calculating the mixing ratio, and then the variables are weighted;

[0020] Four-end-member: Three groups of variables are used as the index variables of the four-end-member mixing ratio calculation model at the same time;

[0021] Among them,

[0022] Similarly, the mixing ratios of points B, C, and D in groundwater can be calculated;

[0023] Three-end-member: Considering the weights of the three groups of variables, the two groups of variables with larger weights are selected as the index variables of the three-end-member mixing ratio calculation model;

[0024] Among them,

[0025] Similarly, the mixing ratios of points B and C in groundwater can be calculated;

[0026] Two-end-member: When there are only two recharge end-members in the mixed water sample, the variable with the largest weight is selected as the index variable of the two-end-member mixing ratio calculation model. If the variable weights are close, calculate them separately and take their average value;

[0027]

[0028] Similarly, the mixing ratio of point D in groundwater can be calculated

[0029] S4. Based on the mixing ratio calculated by the mixed water source identification model, use PHREEQC mixed simulation to quantitatively identify the impact of the mixing degree on the hydrochemistry of the mixed water source.

[0030] In step S4, based on the mixing ratio calculated by the mixed water source identification model, perform PHREEQC mixed simulation, and the simulation value is the theoretical value of the hydrochemistry of the mixed water source under this mixing degree.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. The method proposed by the present invention can accurately identify the recharge end members of the mixed water source of mine water inrush, quantify the mixing degree of the mixed water source, and effectively improve the identification accuracy of the mixed water source of mine water inrush in multi-aquifer mines.

[0033] 2. The present invention quantifies the process of hydrochemical evolution of groundwater in multi-aquifer mines under the influence of mining, providing a theoretical basis for the scientific and reasonable development and protection of mine groundwater.

[0034] 3. By comparing this method with other methods in the prior art, a new solution idea is provided for determining the mixing mode and ratio of groundwater in multi-aquifer mines.

[0035] The method proposed by the present invention is simple, easy to operate, economical and reliable, and can guide the water control work in multi-aquifer mines in production practice. It has important guiding significance for judging the hydraulic connection and hydrochemical evolution direction of multi-aquifers. Description of the Drawings

[0036] Figure 1 Schematic diagram of the working process of a method for quantitatively identifying the mixed water source and mixing degree of mine water inrush in multi-aquifer mines;

[0037] Figure 2 Schematic diagram of the principle of the mixed water source identification model for mine water inrush in multi-aquifer mines;

[0038] Figure 3 Scatter plot of variables in the mixed water source identification model for mine water inrush in multi-aquifer mines. Detailed Embodiments

[0039] Next, in combination with the drawings and specific embodiments, the present invention will be further described. It should be noted that, on the premise of no conflict, any combination of the following-described embodiments or technical features can form a new embodiment.

[0040] Example 1:

[0041] This embodiment is explained by taking a mine in Huaibei Coalfield as an example. After long-term coal mining and drainage work, the mine has a close hydraulic connection between multiple aquifers, and the groundwater in the multiple aquifer mines is mixed to varying degrees. Due to the complex hydrogeological conditions of the mine, the recharge relationship and mixing degree of multiple aquifers need to be ascertained. The evolution of the hydrogeochemical components of groundwater can characterize the recharge relationship and mixing degree of groundwater to a large extent. According to the relevant hydrogeological data of the mine, the main water-filled aquifers of the mine include four aquifers, coal-bearing water, Taihui water and Ordovician water.

[0042] A method for quantitatively identifying mixed water sources and mixing degrees of multi-aquifer mine water inflow, comprising the following steps:

[0043] S1: Systematically collect and organize the hydrogeochemical components of groundwater in multiple aquifers during mine production;

[0044] Systematically collect and organize the hydrogeochemical components of groundwater in multiple aquifers during mine production (Na + , Ca 2+ Mg 2+ , Cl - 、SO4 2- 、HCO3 - , δD and δ 18 O), among which the water sample types include tetrahedral water, coal-bearing water, Taiyang grey water and Ordovician grey water.

[0045] S2. Use mathematical statistics to analyze the basic characteristics of hydrogeochemical components of groundwater in multi-aquifer mines and determine typical water samples of groundwater in multi-aquifer mines;

[0046] The basic characteristics of hydrogeochemical components of early multi-aquifer mine groundwater are statistically analyzed, as shown in Table 1. The mean value of hydrogeochemical components of early groundwater is used as the standard water sample for constructing the mixed water source identification model for multi-aquifer mine water inrush.

[0047] Table 1 Mean values ​​of hydrogeochemical components of groundwater in multi-aquifer mines

[0048]

[0049] S3. Select hydrogeochemical components with stable chemical properties as variables in the multi-aquifer mine water source identification model, identify the recharge source of the mixed water source, and calculate the mixing ratio;

[0050] Based on the theoretical basis of hydrogeochemistry, the hydrogeochemical components with stable chemical properties (Cl - , δD and δ 18O) As variables of the mixed water source identification model for mine water in multi-aquifer mines. During the long-term hydrochemical evolution of mine groundwater, there are certain differences in the weights of the three groups of variables. The entropy weight method is used to assign weights to the three groups of variables, and the basic characteristics of the three groups of variables are shown in Table 2.

[0051] Table 2 Basic characteristics of variables of the mixed water source identification model for mine water in multi-aquifer mines

[0052] Variable <![CDATA[Cl - > δD <![CDATA[δ 18 O]]> Mean value 428.02 -65.03 -8.67 Standard deviation 277.89 5.33 0.78 Entropy value 1.11 1.26 1.26 Weight 0.17 0.42 0.41

[0053] The mine mainly mines Carboniferous and Permian coal seams. In order to identify the mixing degree of the mixed water sources of mine water in multi-aquifer mines under mining influence, 12 groups of water samples of coal measure water and Taiyuan limestone water in the mine under mining influence are collected, including 7 groups of coal measure water and 5 groups of Taiyuan limestone water (Table 3).

[0054] Table 3 Hydrogeochemical components of mine groundwater

[0055]

[0056] Based on the means and standard deviations of the three groups of variables (Cl - , δD and δ 18 O) in Table 2, the water samples to be judged are standardized, and a spatial scatter plot of the variables of the multi-endmember mixing pattern identification model for mine groundwater under mining action is drawn ( Figure 3 ).

[0057] Based on the principle of the multi-endmember mixing pattern identification model, the mixed recharge sources of the water samples to be judged are determined, and then the contribution mixing ratios of the recharge endmembers are calculated (Table 4).

[0058] Table 4 Calculation results of the mixing ratios of mine groundwater

[0059]

[0060] S4. Based on the mixing ratios calculated by the mixed water source identification model, the PHREEQC mixing simulation is used to quantitatively identify the influence of the mixing degree on the hydrochemistry of the mixed water source;

[0061] Based on the calculation results of the mixing pattern identification model, the recharge endmembers and their contribution mixing ratios for the PHREEQC mixing simulation are determined, and the theoretical values of the hydrogeochemical components of mine groundwater under the mixing action are obtained (Table 5).

[0062] Table 5 Theoretical values of hydrogeochemical components of groundwater under the mixing action.

[0063] Number Water sample type <![CDATA[Na + > <![CDATA[Ca 2+ > <![CDATA[Mg 2+ > <![CDATA[Cl - > <![CDATA[SO4 2- > <![CDATA[HCO3 - > 1 Coal measure water 543.49 49.36 22.08 407.19 51.05 1072.99 2 Coal measure water 554.07 35.38 16.45 355.71 39.53 1144.97 3 Coal measure water 545.56 65.04 28.42 470.73 63.42 1026.02 4 Coal measure water 497.03 75.68 32.81 495.23 71.32 871.08 5 Coal measure water 494.04 72.24 31.44 480.67 68.76 875.35 6 Coal measure water 485.99 54.16 24.89 414.64 56.28 888.77 7 Coal measure water 521.18 30.00 14.19 320.92 34.84 1086.41 8 Taiyuan limestone water 391.69 1.95 6.25 205.12 17.69 742.98 9 Taiyuan limestone water 407.33 1.90 5.97 207.43 17.01 789.95 10 Taiyuan limestone water 529.92 2.38 2.99 213.67 9.75 1200.48 11 Taiyuan limestone water 493.12 1.62 4.49 220.10 13.29 1047.37 12 Taiyuan limestone water 537.05 1.49 3.75 226.60 11.37 1179.74

[0064] The above embodiments are only preferred embodiments of the present invention, and cannot be used to limit the scope of protection of the present invention. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection required by the present invention.

Claims

1. A method for quantitatively identifying the mixed water source and mixing degree of mine water inflow in multiple aquifers, characterized in that The method includes the following steps: S1. Collect and collate the hydrogeochemical components of groundwater in multiple aquifers during mine production; S2. Analyze the basic characteristics of the hydrogeochemical components of groundwater in a multi-aquifer mine using mathematical statistics methods, and determine the typical water samples of groundwater in the multi-aquifer mine; S3. Select hydrogeochemical components with stable chemical properties as variables for the mixed water source identification model of mine water inflow in multiple aquifers, identify the recharge sources of the mixed water source, and calculate the mixing ratio; S4. Based on the mixing ratio calculated by the mixed water source identification model, use PHREEQC mixing simulation to quantitatively identify the influence of the mixing degree on the water chemistry of the mixed water source; In step S3, based on the hydrogeochemical theory, a hydrogeochemical component Cl with stable chemical properties is selected. - , δD and δ 18 O is used as a model variable for mixed water source identification; In the step S3, based on Cl - , δD and δ 18 The mean and standard deviation of O are used to standardize the variables of the multi-endmember mixing pattern recognition model, and the entropy weight method is used to calculate the weights of the three variables; In step S3, first use Origin to plot the spatial scatter plot of the standardized Cl - , δD, and δ 18 O, and then determine the relationship between the mixed water sample S and the tetrahedron ABCD. The tetrahedron ABCD is a tetrahedron composed of four typical water samples. Assume that the four corner points of the tetrahedron ABCD correspond to the four faces ΠA, ΠB, ΠC, and ΠD respectively, and the corresponding normal vectors are , , , and . Define the positive direction of the normal vector as outward from the tetrahedron. A x , B x , C x , D x are arbitrary points on the four faces, and P is an arbitrary point in space. Then the spatial vectors are , , , and . And judge the mixing degree according to the following method; , , , If all are simultaneously less than zero, then point P is inside the tetrahedron ABCD, indicating that the mixed water sample receives recharge from four aquifers; When is greater than zero, , , is less than zero, indicating that the mixed water sample P does not receive recharge from the aquifer represented by B; When and are greater than zero, and are less than zero, indicating that the mixed water sample P does not receive recharge from the aquifers represented by A and B; , , greater than zero, less than zero, indicating that the mixed water sample P does not receive recharge from the aquifers represented by A, B, and C, i.e., the mixing effect is weak; In step S3, according to the number of recharge end members of the mixed water source, corresponding mixing ratio calculation models of four-end member, three-end member, and two-end member are constructed respectively. And to ensure the accuracy of the model, the weights need to be calculated based on the entropy weight method before calculating the mixing ratio, and then the variables are weighted; Four-end member: Three groups of variables are simultaneously used as the index variables of the four-end member mixing ratio calculation model; , where ; Similarly, calculate the mixing ratios of points B, C, and D in the groundwater; Three-end member: Considering the weights of the three groups of variables, select the two groups of variables with larger weights as the index variables of the three-end member mixing ratio calculation model; , where ; Similarly, calculate the mixing ratios of points B and C in the groundwater; Two-end member: When there are only two recharge end members in the mixed water sample, select the variable with the largest weight as the index variable of the two-end member mixing ratio calculation model. If the variable weights are close, calculate and take their average values respectively; ； Similarly, calculate the mixing ratio of point D in the groundwater.

2. The quantitative identification method for mixed water sources and mixing degrees of mine water inflow in multiple aquifers as described in claim 1, characterized in that, In step S1, the hydrogeochemical components are obtained by collecting water samples flowing from the underground water discharge holes or water outlets during mine production, sealing and testing them, including but not limited to comprehensive indicators, conventional hydrochemistry, isotopes, and trace elements.

3. The quantitative identification method for mixed water sources and mixing degrees of mine water inflow in multiple aquifers as described in claim 1, characterized in that, In step S1, the multi-aquifer mine from top to bottom is successively the bottom aquifer of the loose layer - bottom aquifer, the sandstone fissure aquifer of the Permian coal series - coal series, the karst fissure aquifer of the Carboniferous Taiyuan Formation - Taiyuan limestone, and the karst fissure aquifer of the Ordovician - Ordovician limestone.

4. The quantitative identification method for mixed water sources and mixing degrees of mine water inrush from multiple aquifers according to claim 1, characterized in that In step S2, use mathematical statistics methods to determine the basic characteristics of the hydrogeochemical components of the multi-aquifer mine, and the basic characteristics include but are not limited to the maximum value, minimum value, mean value, and standard deviation.

5. A method for quantitatively identifying the mixed water sources and mixing degree of mine water inflow in multiple aquifers as described in claim 1, characterized in that In step S4, based on the mixing ratio calculated by the mixed water source identification model, conduct PHREEQC mixing simulation, and the simulation value is the theoretical value of the water chemistry of the mixed water source under this mixing degree.

Images