Top plate gushing water source identification method based on geographic information and coupled with water quality evolution

Abstract

The invention discloses a roof gushing water source identification method based on geographic information and coupled with water quality evolution. Comprising the following steps: S1, data collection and geographical informatization of geological conditions and hydrogeological conditions of a research area; S2, mineral composition analysis and water-rock action chemical reaction judgment of a surrounding rock core of a water burst path; S3, roof water characteristic ion evolution law analysis and water chemical data updating of a target aquifer; and S4, preliminary judgment of a water-filled aquifer and roof water source identification based on PCA-SVM (Principal Component Analysis-Support Vector Machine). According to the method, corresponding coal seam mining thickness, water flowing fissure zone development height and stratigraphic position information can be selected according to the water gushing coordinates so as to judge the aquifer possibly participating in water gushing, the water gushing quality evolution result is determined by combining geochemical simulation, the water source recognition database is updated according to the evolution result, and the water source recognition accuracy is improved. And taking the updated database as a water source identification standard, thereby solving the problem that the water source is inaccurately judged after the water quality evolution of the gushing water.

Description

Technical Field

[0001] The present invention relates to the field of mine water control and prevention, and particularly to a method for identifying the roof water inrush source based on geographic information and coupled with water quality evolution. Background Technique

[0002] Coal occupies the primary position in China's primary energy structure. The safe and efficient exploitation of coal resources is related to national energy security and development. During the coal mining process, various mining accidents are faced with threats. Among them, mine water disaster accidents are characterized by strong suddenness, wide occurrence area, fast flooding speed, great harmfulness and difficult emergency rescue, making it an important factor restricting the safe production of coal mines. Mine water source identification is an important basis for carrying out water control and prevention work. Therefore, accurate and efficient identification of water inrush sources is of great significance for the safe production of coal mines.

[0003] Currently, common water source identification methods can be divided into water temperature and water level method, mathematical theory analysis method and hydrochemical analysis method. Among them, water chemical composition is an important information source for inferring the characteristics of aquifers. However, in the current related methods, there is no combination of the phenomenon of mine water quality evolution during the aquifer water inrush process and water source identification. The mine water source identification model based on hydrochemistry mostly uses the original aquifer hydrochemistry as the database. In actual situations, the aquifer water body will continuously undergo water-rock interaction with the strata rock mass during the migration process, resulting in drastic evolution of its water quality during the migration process. If the influence of water quality evolution during the migration of the aquifer water body is ignored in the water source identification model, it will often lead to a reduction in the accuracy and applicability of the water source identification model, and even be completely inapplicable in some mining areas. Summary of the Invention

[0004] The present invention provides a method for identifying the roof water inrush source based on geographic information and coupled with water quality evolution, which is applicable to the scenario of identifying the roof water inrush source with unstable water inrush quality under special hydrogeological conditions.

[0005] The present invention mainly adopts the following technical means to solve the above technical problems:

[0006] A method for identifying the roof water inrush source based on geographic information and coupled with water quality evolution, comprising:

[0007] S1 Collection and geographic informatization of geological conditions and hydrogeological conditions data in the study area: Collect data on various geological conditions and hydrogeological conditions in the study area and perform their geographic informatization, that is, take each item of data as the additional attribute of the coordinate point. For the information points with insufficient data in the study area, on-site sampling needs to be completed, or the interpolation method is used to effectively distribute each additional attribute at various positions in the mining area;

[0008] Analysis of the mineral composition of the surrounding rock core of the water inrush path S2 and judgment of the chemical reactions of water-rock interaction: When water inrush occurs, determine the location information of the water inrush, retrieve the coal seam mining thickness and the main water-bearing layer horizons corresponding to this location in the geographic information system, count the mining thickness and the measured data of the water-conducting fissure zone of the main working faces of the surrounding coal mines, and determine the development height of the water-conducting fissure zone at this location by the similar analogy method. Compare the water-bearing layer horizons to judge the aquifers participating in this water inrush.

[0009] Analysis of the evolution law of characteristic ions in roof water S3 and update of the hydrochemical data of the target aquifer: The method for updating the aquifer hydrochemical database is to take core samples of the target formation through surface or underground exploration boreholes, analyze the main mineral components existing in the rock samples, judge the possible chemical reactions between the main mineral components and the roof water, simulate the changes of characteristic ions in the migration path of the roof water through hydrogeochemical reactions, and update the initial aquifer hydrochemical database based on the results of the characteristic ion changes to form the hydrochemical database after the evolution of the water inrush water quality.

[0010] Preliminary discrimination of the water-filled aquifer S4 and identification of the roof water source based on PCA-SVM: For the areas with composite roof water inrush, retrieve the hydrochemical database after water quality evolution as the standard samples of the water source identification model; use the principal component analysis method to reduce the dimension of the original index data, determine the main characteristic indexes for discriminating the water source, and apply the machine learning method of support vector machine to identify the water inrush water source.

[0011] Optionally, in the step S1, the geographic information represents the spatial coordinates of the main points in the study area, and the main points include the inflection points of the mining area boundary, the main exploration boreholes in the area, and the roof water inrush points.

[0012] The geological conditions and hydrogeological conditions data involved include the formation lithology and thickness distribution, the main coal seam thickness distribution, the main stratigraphic horizons, and the groundwater chemical data. The groundwater chemical data mainly includes Na + +K + 、Ca 2+ 、Mg 2+ 、Cl - 、HCO3 - 、SO4 2- and F - Seven characteristic ion concentration indexes.

[0013] Optionally, in the step S2, it is considered that on the premise of roughly the same geological conditions, the ratio of the water-conducting fissure zone to the coal seam mining thickness after the mining of different working faces in the same mining area should be basically equal. Therefore, determine this ratio by the similar analogy method, and combine the coal seam mining thickness attributes at different positions in the geographic information to determine the development height of the water-conducting fissure zone of the working face roof.

[0014] Conduct a comparative analysis with the aquifer horizon in the geographic information system to determine the aquifers that may be involved in the current water inrush. When the development height of the water-conducting fissure zone is greater than the distance from the coal seam roof to the aquifer, this aquifer will be involved in the current roof water inrush.

[0015] If the judgment result is that a single aquifer is involved in the water inrush, directly output the water source identification result. If the judgment result is that multiple aquifers are involved in the composite water inrush, the aquifer hydrochemical database needs to be updated.

[0016] Optionally, in step S3, analyze the mineral components of the main lithologies in the roof water inrush path through X-ray diffraction. Judge the possible water-rock interactions based on the main mineral components in the rock samples, and conduct hydrogeochemical inverse simulation through PHREEQC. Set different geochemical simulation paths, assuming that the migration process of the roof water is from point A to point B to point C, where the surrounding rock of the path from point A to point B is mainly composed of mudstone sections, and the surrounding rock of the path from point B to point C is mainly composed of sandstone sections.

[0017] Analyze the changes in the characteristic ion concentrations before and after the roof water runoff passes through the mudstone section and the sandstone section to form the influence law of unit thickness mudstone and sandstone on the main characteristic ion concentrations.

[0018] On this basis, combined with the coal seam roof lithology combination data in the geographic information, form a roof water inrush water quality evolution module with the path of "water source → runoff formation → working face", and apply this module to update the initial aquifer hydrochemical database to form a hydrochemical database after the water inrush water quality evolution.

[0019] Optionally, in step S3: Calculate the saturation index of minerals in the water sample through PHREEQC. The calculation formula for the mineral saturation index is:

[0020]

[0021] In the formula; IAP is the ion activity product; K is the equilibrium constant; SI = 0 indicates that the mineral is in equilibrium, SI < 0 indicates that the mineral is in a dissolved state, and SI > 0 indicates that the mineral is in a precipitated state;

[0022] Use the inverse hydrogeochemical simulation function of PHREEQC to determine the amount of mineral dissolution or precipitation at two points on the underground water flow path.

[0023] Optionally, the influence law of unit thickness mudstone and sandstone on the main characteristic ion concentrations includes:

[0024] Taking the initial groundwater quality as the "starting point", for every unit content of water, x1 (mmol) of the first mineral is dissolved or precipitated. Precipitation is counted as negative, dissolution is counted as positive,..., x nAfter the nth mineral of (mmol), the "end point" water quality is formed; the increase amount of the ith element is b i (mmol), and its mass balance equation is:

[0025]

[0026] In the formula, a ij is the stoichiometric number of the ith element relative to the jth mineral; n is the total number of equilibrium elements in the aqueous solution.

[0027] Optionally, in step S4, if the judgment result is that water gushes from the roof of the composite aquifer, the initial water quality data of multiple aquifers are respectively input into the water quality evolution module, and the output result is used as the characteristic ion concentration index of each aquifer. It is considered that the gushing water quality is the mixed result of the water quality evolution of multiple aquifers. The mixing ratio of each aquifer is deduced by the gushing water quality detection result to determine the main water-inrush aquifer.

[0028] The advantages of the present invention are:

[0029] The method of the present invention can select the corresponding coal seam mining thickness, the development height of the water-conducting fissure zone and the stratigraphic horizon information according to the gushing water coordinates to judge the aquifers that may participate in the gushing water. And by applying the lithological composition and thickness of the gushing water path in the geographic information, combined with the geochemical simulation to determine the gushing water quality evolution result, the water source identification database is updated based on the evolution result, and the updated database is used as the water source identification standard, so as to solve the problem of inaccurate water source discrimination after the gushing water quality evolves. Brief Description of the Drawings

[0030] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and are used to explain the present invention together with the following specific embodiments, but do not constitute a limitation to the present invention. In the drawings:

[0031] Figure 1 Illustrates the work flow chart of the present invention;

[0032] Figure 2 Illustrates the geographic information schematic diagram of the coal thickness data of the embodiment;

[0033] Figure 3 Illustrates the geographic information schematic diagram of the distance data from the 4th coal seam to the bottom of the Yijun Formation in the embodiment;

[0034] Figure 4 Illustrates the geographic information schematic diagram of the thickness data of the Zhiluo Formation in the embodiment;

[0035] Figure 5 Illustrates the geographic information schematic diagram of the thickness data of the Luohe + Yijun Formation in the embodiment;

[0036] Figure 6 Geological information map of the water-conducting fissure zone affecting the Luohe Formation, illustrating an embodiment. Detailed implementation manners

[0037] Next, in combination with the accompanying drawings and specific implementation manners, the present invention will be further described.

[0038] Currently, there is an urgent need for a method for identifying the roof water inrush source that can solve the problem of water quality evolution, which is of great significance for the prevention and control of roof water disasters in mining areas in western China. In response to this problem, the present invention proposes a method for identifying the roof water inrush source based on geographical information and coupled with water quality evolution. This method can select the corresponding coal seam mining thickness, the development height of the water-conducting fissure zone, and the stratigraphic horizon information according to the water inrush coordinates to judge the aquifers that may be involved in the water inrush. And by applying the lithological composition and thickness of the water inrush path in geographical information, combined with geochemical simulation to determine the evolution result of the water inrush water quality, and updating the water source identification database based on the evolution result, and using the updated database as the water source identification standard, so as to solve the problem of inaccurate water source discrimination after the evolution of the water inrush water quality.

[0039] Combined with Figure 1 , the method for identifying the roof water inrush source based on geographical information and coupled with water quality evolution of the present invention includes:

[0040] S1 Collection and geographical informatization of geological conditions and hydrogeological conditions data in the study area: Collect data on various geological conditions and hydrogeological conditions in the study area and geographically informatize them, that is, take each item of data as the additional attribute of the coordinate point. For the information points with insufficient data in the study area, on-site sampling is required for improvement, or the interpolation method is used to effectively distribute each additional attribute at various positions in the mining area.

[0041] Further, in step S1, the geographical information represents the spatial coordinates of the main points in the study area, and the main points include the inflection points of the mining area boundary, the main exploration boreholes in the area, and the roof water inrush points. The geological conditions and hydrogeological conditions data involved include the stratigraphic lithology and thickness distribution, the main coal seam thickness distribution, the main stratigraphic horizons, and the groundwater chemical data, where the groundwater chemical data mainly includes Na + +K + , Ca 2+ , Mg 2+ , Cl - , HCO3 - , SO4 2- , F - Seven indicators, specifically the characteristic ion concentration indicators.

[0042] Analysis of the mineral composition of the surrounding rock core of the water inrush path in S2 and judgment of the chemical reactions of water-rock interaction: When water inrush occurs, determine the location information of the water inrush. Retrieve the coal seam mining thickness and the main water-bearing layer horizons corresponding to this location in the geographic information system. Statistically analyze the mining thickness and the measured data of the water-conducting fissure zone of the main working faces of surrounding coal mines. Determine the development height of the water-conducting fissure zone at this location through the similar analogy method, and compare each water-bearing layer horizon to judge the aquifers participating in this water inrush.

[0043] Further, in step S2, it is considered that on the premise of roughly the same geological conditions, the ratio of the water-conducting fissure zone to the coal seam mining thickness should be basically equal after the mining of different working faces in the same mining area. Therefore, determine this ratio through the similar analogy method, and combine the coal seam mining thickness attributes at different locations in the geographic information to determine the development height of the water-conducting fissure zone in the working face roof.

[0044] Further, conduct a comparative analysis with the water-bearing layer horizons in the geographic information system to judge the aquifers that may participate in this water inrush. When the development height of the water-conducting fissure zone is greater than the distance from the coal seam roof to the aquifer, this aquifer will participate in this roof water inrush.

[0045] If the judgment result is that a single aquifer participates in the water inrush, directly output the water source identification result. If the judgment result is that multiple aquifers have composite water inrush, then it is necessary to update the aquifer hydrochemical database.

[0046] Analysis of the evolution law of characteristic ions in roof water in S3 and update of the hydrochemical data of the target aquifer: The method for updating the aquifer hydrochemical database is to take core samples of the target formation through surface or underground exploration boreholes, analyze the main mineral components existing in the rock samples, judge the possible chemical reactions between the main mineral components and the roof water, and simulate the changes of characteristic ions in the roof water during the migration path through hydrogeochemical reactions. Update the initial aquifer hydrochemical database based on the results of the characteristic ion changes to form a hydrochemical database after the evolution of the water inrush water quality.

[0047] Further, in step S3, analyze the mineral components of the main lithologies in the roof water inrush path through X-ray diffraction (XRD). For example, the main mineral components of mudstone include kaolinite (Al2Si2O5(OH)4), calcite (CaCO3), dolomite (CaMg(CO3)2), albite (NaAlSi3O8), pyrite (FeS2), and the main mineral components of sandstone include quartz (SiO2), albite, and anorthite (CaAl2Si2O8).

[0048] Further, judge the possible water-rock interactions based on the main mineral components in the rock samples. For example, after the oxidation reaction of sulfides such as pyrite, free acid will be generated, and the generated free acid will react with calcite, dolomite, etc. in the formation to undergo a neutralization reaction, thus making the Ca in the roof water 2+, Mg 2+ , SO4 2- The ion contents increase during the migration process, and the reaction chemical formulas are as follows:

[0049] 4FeS2 + 14H2O + 15O2 = 4Fe(OH)3 + 8SO4 2- + 16H +

[0050] CaCO3 + 4H + = Ca 2+ + 2H2O + CO2↑

[0051] MgCa(CO3)2 + 4H + = Mg 2+ + Ca 2+ + 2H2O + 2CO2↑

[0052] Furthermore, since primary rock-forming minerals such as albite and anorthite are not saturated in water, they will still dissolve in the roof water inflow and produce Ca 2+ , Mg 2+ and other ions, and the reaction chemical formulas are as follows:

[0053] 4NaAlSi3O8 + 4CO2 + 22H2O = Al4Si4O 10 (OH)8 + 4Na + + 8H4SiO4 + 4HCO3 -

[0054] 2CaAl2Si2O8 + 4CO2 + 6H2O = Al4Si4O 10 (OH)8 + 2Ca 2+ + 4HCO3 -

[0055] Furthermore, through PHREEQC for hydrogeochemical inverse simulation, different geochemical simulation paths are set. Assuming the migration process of the roof water is from point A to point B to point C, where the surrounding rock of the path from point A to point B is mainly composed of a certain thickness of mudstone section, and the surrounding rock of the path from point B to point C is mainly composed of a section of sandstone.

[0056] Furthermore, analyze the changes in the characteristic ion concentrations before and after the roof water runoff passes through the mudstone section and the sandstone section to form the influence law of the unit thickness of mudstone and sandstone on the main characteristic ion concentrations.

[0057] Assuming that the initial water quality of groundwater is the "starting point", x1 (mmol) of the first mineral is dissolved (or precipitated) in each unit content of water (precipitation is negative, dissolution is positive),..., x nAfter the nth mineral of (mmol), the "end point" water quality is formed. The increase of the ith element is b i (mmol), and its mass balance equation is:

[0058]

[0059] In the formula, a ij is the stoichiometric number of the ith element relative to the jth mineral; n is the total number of equilibrium elements in the aqueous solution.

[0060] Furthermore, on this basis, combined with the data of the lithological combination of the coal seam roof in the geographical information, a roof water inrush water quality evolution module with the path of "water source → runoff stratum → working face" is formed. This module is used to update the initial aquifer hydrochemical database, and a hydrochemical database after the evolution of the water inrush water quality is formed.

[0061] S4 Preliminary discrimination of water-filled aquifers and identification of roof water sources based on PCA-SVM: For the areas with complex roof water inrush, the hydrochemical database after water quality evolution is retrieved as the standard sample of the water source identification model. The principal component analysis method is used to reduce the dimension of the original index data to determine the main characteristic indexes for discriminating water sources, and the machine learning method of support vector machine is used to identify the water inrush water sources.

[0062] Furthermore, if the judgment result is the roof water inrush of a composite aquifer, the initial water quality data of multiple aquifers are respectively input into the water quality evolution module, and the output result is used as the characteristic ion concentration index of each aquifer. It is considered that the water inrush water quality is the mixed result of the water quality evolution of multiple aquifers. The mixing ratio of each aquifer is deduced from the water inrush water quality detection result to determine the main water-filled aquifer.

[0063] Example 1:

[0064] This example is illustrated by a roof water inrush event with a water volume of 500 m 3 / d in a certain mine in the Binchang Mining Area. The Cretaceous Luohe Formation aquifer is the main water-filled aquifer in this area. The salinity of this aquifer is low (510 - 550 mg / L), belonging to HCO3 - Ca·Na·Mg type water; at the same time, the Jurassic Yan'an-Zhiluo Formation aquifer is also distributed. The salinity of this aquifer is generally high, ranging from 2400 to 4700 mg / L, and the water quality type is mostly SO4·Cl - Na. Generally, the results of the water source discrimination model based on water quality analysis show that the water inrush source at the working face tends to be the Jurassic aquifer. However, after the water inrush, the water level of the Luohe Formation aquifer shows a significant downward trend, and in previous hydrogeological work, it was considered that the Jurassic aquifer has extremely weak water-richness and is difficult to support a large flow of water inrush. Therefore, the water source discrimination result is unconvincing.

[0065] Based on this, this example explains this phenomenon through a roof water inrush source identification method based on geographic information and coupled with water quality evolution, including the following steps:

[0066] S1: Collect data such as the thickness of the main mined coal seam, groundwater level, thickness of the main water-bearing (confining) layer, distance from the main mined coal seam to the main aquifer, water quality of the aquifer, and lithology of the Jurassic strata in the study area and carry out geographic informatization (as Figures 2 to 5 shown). Table 1 lists the lithology combination of the strata exposed by some boreholes.

[0067] Table 1 Statistical table of lithology combination of Jurassic strata Collect and sort out the special exploration research carried out in multiple mines in the Binchang mining area and the actual exposure results of mining. The measured results show that the ratio of the development height of the water-conducting fissure zone to the mining thickness of the working face is between 22.3 and 38.5. The statistical results are shown in Table 2.

[0068] Table 2 Statistical table of crack-to-mining ratio of surrounding coal mines

[0069]

[0070]

[0071] The mining thickness of the water-inflow working face is about 8m. By using the analogy method, it is analyzed that the development height of the water-conducting fissure zone at this position should be between 178.4m and 236m. The distance from the working face roof to the Luohe Formation aquifer is 143m. Based on the drilling data of each borehole, use the natural neighbor interpolation method to draw the geographic information distribution map of whether the water-conducting fissure zone of this coal mine can reach the Luohe Formation aquifer (as Figure 6 shown). The black part is the area where the water-conducting fissure zone can reach the Luohe Formation aquifer. The post-mining roof water inrush occurring in this area is the mixed water inrush participated by both the Zhiluo Formation and the Luohe Formation. It is necessary to update the water chemical database of the Luohe Formation and then participate in the water source identification.

[0072] S2: Sample the Jurassic strata through the ground borehole D47. Through X-ray diffraction (XRD), the main mineral components of sandy mudstone are quartz and albite, the main mineral components of mudstone are montmorillonite, kaolin and a small amount of quartz, and the main mineral components of sandstone are quartz, feldspar and a small amount of calcite and pyrite. Therefore, when roof water inrush occurs at the working face near borehole D47, when the water body of the Luohe Formation aquifer flows through the Jurassic strata, it will react with the 51-meter sandy mudstone section, the 29-meter sandstone section and the 63-meter mudstone section. The main minerals participating in the water-rock reaction are albite, calcite and pyrite. The possible chemical reactions are mainly of the following types: Albite dissolves in unsaturated Luohe water to produce kaolin, sodium ions and bicarbonate ions; after the oxidation reaction of pyrite, free hydrogen ions and sulfate ions will be produced; calcite reacts with free hydrogen ions to produce calcium ions and carbon dioxide.

[0073] The main reaction equations that occur when the Luohe water flows through the Jurassic strata are as follows:

[0074] 4NaAlSi3O8 + 4CO2 + 22H2O = Al4Si4O 10 (OH)8 + 4Na + + 8H4SiO4 + 4HCO3 -

[0075] 4FeS2 + 14H2O + 15O2 = 4Fe(OH)3 + 8SO4 2- + 16H +

[0076] CaCO3 + 4H + =Ca 2+ + 2H2O + CO2↑

[0077] S3: Calculate the saturation index of minerals such as albite, calcite and pyrite in the water sample through PHREEQC. The calculation formula of the mineral saturation index is:

[0078]

[0079] In the formula: IAP is the ion activity product; K is the equilibrium constant. SI = 0 indicates that the mineral is in an equilibrium state, SI < 0 indicates that the mineral is in a dissolved state, and SI > 0 indicates that the mineral is in a precipitation state.

[0080] Furthermore, using the inverse hydrogeochemical simulation function of PHREEQC, determine the amount of mineral dissolution or precipitation at two points on the underground water flow path. The dissolution equilibrium reaction of the mineral phase is expressed as follows:

[0081] SOLUTION 1LuoHe aquifer Name the solution and define the ion content in the solution:

[0082]

[0083]

[0084] Sulfate61.91

[0085] Phases Components participating in the reaction

[0086] Halite

[0087] Gypsum

[0088]

[0089] PHASES

[0090] Albite

[0091] 4NaAlSi3O8 + 4CO2 + 22H2O = Al4Si4O 10 (OH)8 + 4Na + + 8H4SiO4 + 4HCO3 - Logk 0.0

[0092] Marcasite

[0093] 4FeS2 + 14H2O + 15O2 = 4Fe(OH)3 + 8SO4 2- + 16H +

[0094] Calcite

[0095] CaCO3 + 4H + =Ca 2+ + 2H2O + CO2↑

[0096] END。

[0097] When the water body of the Luohe Formation aquifer flows through the Jurassic strata, the reactant components and molar conversion results are shown in Table 3 below.

[0098] Table 3 Reactant components and molar conversion results during water inrush

[0099]

[0100]

[0101] S4: Based on the reactant components and the molar conversion results, establish the evolved hydrochemical database of roof water inrush; and determine whether there is information overlap among multiple indicators through ion correlation analysis, conduct principal component analysis on the samples to reduce information overlap, achieve the purpose of reducing the calculation load and improving the accuracy of water source discrimination. Standardize each indicator through neural network training, and finally select TDS as the characteristic factor for this water source identification. Table 4 is the explained variance ratio table of this principal component analysis.

[0102] Table 4 Explained Variance Ratio Table of Principal Components

[0103]

[0104] The calculation results of water quality evolution show that the initial TDS of the water body in the Luohe Formation aquifer near the D47 borehole is 516.3 mg / L. After passing through 143 m of the Jurassic strata, its TDS evolves to 2721.1 mg / L. Use the neural network model of support vector machine to identify the composite roof water inrush, and determine that the main recharge aquifer for this water inrush is the Luohe Formation aquifer, and the water volume it participates in the water inrush accounts for 87.9% of the total water volume. The judgment result is consistent with the water-richness and water level observation analysis results of the main aquifers in this mining area, and it is considered that the water source discrimination result this time is accurate.

[0105] The present invention takes factors such as coal seam mining thickness, formation lithology, and hydrochemical characteristics of the aquifer as information and attaches them to the geographical location. Compared with traditional water source identification methods, more identification factors can be attached, and a water quality evolution module is added to the traditional water source discrimination model, solving the problems of large water quality change range under special hydrogeological conditions and low accuracy of traditional water source discrimination models, and achieving rapid and efficient identification of roof water inrush sources under water quality evolution conditions.

[0106] Although the present invention has been described in detail above with general descriptions and specific implementation cases, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A method for identifying the water inrush source of the roof based on geographical information and coupling water quality evolution, characterized in that Including: S1 Collection of geological and hydrogeological condition data in the study area and its geographic informatization: Collect data on various geological and hydrogeological conditions in the study area and perform its geographic informatization, that is, take various data as additional attributes of coordinate points. For information points with insufficient data in the study area, on-site sampling is required for improvement, or interpolation method is used to effectively distribute various additional attributes at each location in the mining area; S2 Analysis of the mineral composition of the surrounding rock core of the water inrush path and judgment of the chemical reactions of water-rock interaction: When water inrush occurs, determine the location information of the water inrush. In the geographic information system, retrieve the coal seam mining thickness and the main aquifer horizons corresponding to this location, and count the measured data of the mining thickness and the water-conducting fissure zone of the main working faces of surrounding coal mines. Determine the development height of the water-conducting fissure zone at this location by the similar analogy method, and compare each aquifer horizon to judge the aquifers participating in this water inrush; S3 Analysis of the evolution law of characteristic ions in roof water and update of the hydrochemical data of the target aquifer: The method for updating the hydrochemical database of the aquifer is to take core samples of the target formation through surface or underground exploration boreholes, analyze the main mineral components existing in the rock samples, judge the possible chemical reactions between the main mineral components and the roof water, and simulate the changes of characteristic ions in the roof water during the migration path through hydrogeochemical reactions. Update the initial hydrochemical database of the aquifer based on the results of the characteristic ion changes to form a hydrochemical database after the evolution of the water inrush water quality. S4 Preliminary discrimination of the water-filled aquifer and identification of the roof water source based on PCA-SVM: For the area with complex roof water inrush, retrieve the hydrochemical database after water quality evolution as the standard sample of the water source identification model; Use the principal component analysis method to reduce the dimension of the original index data, determine the main characteristic indicators for discriminating the water source, and apply the machine learning method of support vector machine to identify the water inrush water source.

2. The roof water inrush water source identification method based on geographic information and coupled with water quality evolution according to claim 1, wherein In the step S1, the geographic information represents the spatial coordinates of the main points in the study area, and the main points include the inflection points of the mining area boundary, the main exploration boreholes in the area, and the roof water inrush points; The geological and hydrogeological condition data involved include the formation lithology and thickness distribution, the thickness distribution of the main coal seams, the main stratigraphic horizons and the groundwater chemical data. Among them, the groundwater chemical data mainly include Na + +K + 、Ca 2+ 、Mg 2+ 、Cl - 、HCO3 - 、SO4 2- and F - Seven characteristic ion concentration indicators.

3. The roof water inrush water source identification method based on geographic information and coupled with water quality evolution according to claim 1 or 2, characterized in that In the step S2, it is considered that on the premise of roughly the same geological conditions, the ratio of the water-conducting fissure zone to the coal seam mining thickness after the mining of different working faces in the same mining area should be basically equal. Therefore, determine this ratio by the similar analogy method, and combine the coal seam mining thickness attributes at different positions in the geographic information to determine the development height of the water-conducting fissure zone of the working face roof; Conduct a comparative analysis with the aquifer horizons in the geographic information system to judge the aquifers that may participate in this water inrush; When the development height of the water-conducting fissure zone is greater than the distance from the coal seam roof to the aquifer, this aquifer will participate in this roof water inrush; If the judgment result is that a single aquifer participates in the water inrush, directly output the water source identification result; If the judgment result is that multiple aquifers are involved in the composite water inrush, the hydrochemical database of the aquifer needs to be updated.

4. The roof water inrush source identification method based on geographic information and coupled with water quality evolution according to claim 1 or 2, characterized in that, In the step S3, the mineral components of the main lithologies in the roof water inrush path are analyzed by X-ray diffraction; the possible water-rock interactions are judged according to the main mineral components in the rock samples, and the hydrogeochemical inverse simulation is carried out by PHREEQC. Different geochemical simulation paths are set, and it is assumed that the migration process of the roof water is from point A to point B to point C. Among them, the surrounding rock of the path from point A to point B is mainly composed of mudstone sections, and the surrounding rock of the path from point B to point C is mainly composed of sandstone sections; Analyze the changes in the characteristic ion concentrations before and after the roof water runoff passes through the mudstone section and the sandstone section to form the influence law of the unit thickness of mudstone and sandstone on the main characteristic ion concentrations; On this basis, combined with the coal seam roof lithology combination data in the geographic information, a roof water inrush water quality evolution module with the path of "water source → runoff stratum → working face" is formed. This module is used to update the initial aquifer hydrochemical database to form a hydrochemical database after the water quality of the water inrush has evolved.

5. The method for identifying the water inrush source of the roof based on geographic information and coupled with water quality evolution according to claim 4, wherein In the step S3: Calculate the saturation index of the minerals in the water sample by PHREEQC. The calculation formula of the mineral saturation index is: In the formula; IAP is the ion activity product; K is the equilibrium constant; SI = 0 indicates that the mineral is in equilibrium, SI < 0 indicates that the mineral is in a dissolved state, and SI > 0 indicates that the mineral is in a precipitated state; Use the inverse hydrogeochemical simulation function of PHREEQC to determine the amount of mineral dissolution or precipitation at two points on the underground water flow path.

6. The method for identifying the water inrush source of the roof based on geographical information and coupled with water quality evolution according to claim 4, characterized in that The influence law of the unit thickness of mudstone and sandstone on the main characteristic ion concentrations includes: Taking the initial groundwater quality as the "starting point", for every x1 (mmol) of the first mineral dissolved or precipitated in each unit content of water, precipitation is recorded as a negative value and dissolution as a positive value,..., after the nth mineral of x n (mmol), the "end point" water quality is formed; among which, the increase in the i-th element is b i (mmol), and its mass balance equation is: where a ij is the stoichiometric number of the i-th element relative to the j-th mineral; n is the total number of equilibrium elements in the aqueous solution.

7. The method for identifying the water inrush source of the roof based on geographic information and coupled with the water quality evolution according to claim 1 or 2, characterized in that, In the step S4, if the judgment result is that the roof water inrush is from the composite aquifer, the initial water quality data of multiple aquifers are respectively input into the water quality evolution module, and the output result is used as the characteristic ion concentration index of each aquifer. It is considered that the water quality of the water inrush is the mixed result of the water quality evolution of multiple aquifers. The mixing ratio of each aquifer is deduced by the water quality detection result of the water inrush to determine the main water filling aquifer.

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