Bedrock top wind oxidation zone waterproof effect evaluation method

Abstract

The invention discloses a bedrock top wind oxidation zone waterproof effect evaluation method, which belongs to the technical field of mine water disaster prevention and control, and comprises the following steps: firstly, collecting and analyzing various existing geological results of an evaluation area, and determining the spatial distribution range, thickness change and transverse continuity characteristics of a bedrock top wind oxidation zone of the evaluation area through multi-source data integration; then screening key geological information types directly related to the water insulation effect of the wind oxidation zone from the multivariate geological information based on the distribution characteristics of the wind oxidation zone at the top of the bedrock and the water insulation performance influence mechanism, calculating the weight value of each kind of geological information by adopting an improved CRITIC weight method, and aiming at the same geographic position, calculating the weight value of each kind of geological information; and carrying out weighted superposition integration on the standardized multivariate geological data and the corresponding weight to obtain a superposition value. According to the method, the multi-source geological information is converted into the Xd numerical value capable of being directly compared through standardization processing and weighted stacking, accurate positioning of the waterproof performance is achieved through the four-level classification standard, and a quantitative basis is provided for differential prevention and control.

Description

Technical Field

[0001] This invention belongs to the field of mine water hazard prevention and control technology, specifically relating to a method for evaluating the water-blocking effect of the wind-oxidized zone at the top of bedrock. Background Technology

[0002] In underground mining, the development of water-conducting fracture zones in the roof of coal seams or ore bodies is one of the main causes of water hazards. When these fracture zones extend upwards to the weathered oxidation zone at the top of the bedrock, if the weathered oxidation zone lacks sufficient water-resistant properties, the overlying loose aquifer or surface water may flow into the mine through the fracture channels, causing a water inrush accident. The weathered oxidation zone at the top of the bedrock is significantly altered in its rock structure, mineral composition, and physical and mechanical properties due to long-term weathering and oxidation, resulting in strong spatial heterogeneity in its water-resistant properties.

[0003] Current technologies for evaluating the water-retaining performance of wind-oxidized zones largely rely on qualitative descriptions. For example, judging the presence or weakness of water-retaining properties using only a single indicator fails to quantify the differences in water-retaining capacity across different areas. This limitation leads to a lack of precision in mine flood control measures: in areas with good water-retaining performance, excessive coal pillars may be left, resulting in resource waste, while in areas with weak water-retaining properties, insufficient prevention and control may lead to water hazards. Therefore, establishing a quantitative evaluation method that integrates multi-dimensional geological information is of great significance for improving the level of mine water hazard prevention and control. Summary of the Invention

[0004] The purpose of this invention is to provide a method for evaluating the water-blocking effect of the wind-oxidized zone at the top of bedrock, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock, wherein the evaluation method is as follows:

[0006] S1. Collect and analyze existing geological results in the evaluation area, and determine the spatial distribution range, thickness variation and lateral continuity characteristics of the wind oxidation zone at the top of the bedrock in the evaluation area through multi-source data integration;

[0007] S2. Then, based on the distribution characteristics of the wind oxidation zone at the top of the bedrock and the mechanism of its water-retaining performance, key geological information types directly related to the water-retaining effect of the wind oxidation zone were screened from multi-dimensional geological information.

[0008] S3. For the selected multivariate geological information of different order of magnitude and different units of measurement, a standardized formula is used to unify the dimensions and eliminate the interference caused by data differences.

[0009] S4. The improved CRITIC weighting method is used to calculate the weight values ​​of various geological information. The weight values ​​are determined based on data volatility and index correlation. For the same geographical location, the standardized multivariate geological data and the corresponding weights are weighted and superimposed to obtain the superimposed values.

[0010] S5. Draw contour maps based on the distribution characteristics of superimposed values, classify the barrier effect of the wind oxidation zone at the top of the bedrock on the loose water body into four levels: excellent, good, poor, and very poor, and form a visual comprehensive evaluation map.

[0011] Preferably, in S1, the existing geological results in the evaluation area include geological exploration data, geophysical data, geochemical data, and remote sensing image data. Among them, the geological exploration data includes borehole data, core descriptions, and rock mechanical properties; the geophysical data includes resistivity, spontaneous potential, and seismic wave velocity; the geochemical data is used to analyze the distribution and migration patterns of elements in rocks; and the remote sensing image data is used to provide information on landform and vegetation cover.

[0012] Preferably, in S2, the key geological information types directly related to the water-blocking effect of the wind oxidation zone include the thickness of the bedrock wind oxidation zone, the proportion of sandstone and mudstone in the wind oxidation zone, the saturated water absorption rate of the rock, the equivalent permeability coefficient of the rock in the wind oxidation zone, the rock quality index RQD, the rock and soil strength of the wind oxidation zone, and the degree of wind oxidation.

[0013] Preferably, in S3, the standardization process uses the following formula: X ib =±(X i -X m ) / (X max -X min (where X) ib X is the standardized value of measured geological data at any location. max To evaluate the maximum value of this type of geological data within the evaluation area, X min To evaluate the minimum value of this type of geological data within the area, X i To evaluate the measured value of this type of geological data at any location within the evaluation area, X m To evaluate the background values ​​of this type of geological data in the area, the median value is used when there are no background values.

[0014] Preferably, a "+" sign is used when the geological data involved in the evaluation is correlated with a positive anomaly, and a "-" sign is used when the geological data involved in the evaluation is correlated with a negative anomaly.

[0015] Preferably, in S4, the process of calculating weights using the improved CRITIC weighting method includes: characterizing volatility by the ratio of the data standard deviation to the median; the greater the volatility, the higher the weight percentage; then calculating the correlation between different geological information types; the smaller the correlation, the higher the weight percentage; finally, determining the weight value based on the comprehensive volatility and correlation, and the sum of the weight values ​​for all geological information types is 1.

[0016] Preferably, by the coefficient of variation C Vj =σj / Medianj calculates data volatility, where σj is the standard deviation of the j-th type of geological data, Medianj is the median of the j-th type of geological data, and combines it with the index conflict R=C Vj The weight is calculated as ×(1-r(k)), where r(k) is the correlation coefficient between the j-th type of geological data and other geological data.

[0017] Preferably, in S4, the weighted superposition integration adopts the formula: X d =W1X i b1+W2X i b2+W3X i b3+……+W i X i b i Among them, X d X represents the summed values. i b i Let W be the standardized value of the i-th type of geological data. i W represents the weight of the i-th type of geological data. i The value ranges from 0 to 1, and the smaller the correlation and the greater the volatility between geological data types, the larger the value of Wi.

[0018] Preferably, in S5, the standard for classifying the barrier effect level is as follows:

[0019] Advantages: X d A value greater than 0.6 indicates an intact wind oxidation zone structure and strong water-resistant performance;

[0020] Good:X d The value is between 0.3 and 0.6, the wind oxidation zone structure is relatively complete, and the water-proof performance is strong;

[0021] Poor: X d The value is between -0.3 and 0.3, indicating that the wind oxidation zone has localized crack development and its water-proofing performance is generally poor.

[0022] Difference: X d If the value is less than -0.3, the wind oxidation zone structure is broken and the water-proof performance is weak.

[0023] Preferably, in S5, the visualization is rendered using Surfer or ArcGIS software to draw X. dThe contour lines are filled with different colors according to their levels to form a comprehensive evaluation map of the waterproofing effect.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. This invention transforms multi-source geological information into directly comparable X data through standardization and weighted overlay. d The numerical values, along with the four-level classification standard, enable precise positioning of water-resistant performance, providing a quantitative basis for differentiated prevention and control.

[0026] 2. This invention adopts an improved CRITIC weighting method, which dynamically calculates weights based on the volatility of the data itself and the independence of the indicators, avoiding the subjective bias of human weighting in traditional methods. Compared with the fixed weighting method, it can effectively improve the fit between the evaluation results and the actual water inflow.

[0027] 3. This invention integrates multi-dimensional data such as geological exploration, geophysics, geochemistry and remote sensing images, covering all elements such as rock structure, physical properties, chemical characteristics and surface morphology, avoiding the one-sidedness of single data types, and intuitively presents the spatial distribution of water-retaining performance through contour maps and color grading, providing clear guidance for optimizing prevention and control measures. Attached Figure Description

[0028] Figure 1 This is a flowchart of the process of the present invention;

[0029] Figure 2 This is a strength diagram of soil and rock in the wind-oxidized zone.

[0030] Figure 3 This is a diagram illustrating the evaluation steps of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figures 1-3This invention provides a method for evaluating the water-blocking effect of the wind-oxidized zone at the top of bedrock. S1: Collect and analyze various existing geological results in the evaluation area. These results include geological exploration data, geophysical data, geochemical data, and remote sensing image data. The geological exploration data includes borehole data, core descriptions, and rock mechanical properties. The geophysical data includes resistivity, spontaneous potential, and seismic wave velocity. The geochemical data is used to analyze the distribution and migration patterns of elements in the rocks. The remote sensing image data is used to provide information on surface morphology and vegetation cover. By integrating multi-source data, the spatial distribution range, thickness variation, and lateral continuity characteristics of the wind-oxidized zone at the top of bedrock in the evaluation area are determined.

[0033] S2. Then, based on the distribution characteristics of the wind-oxidation zone at the top of the bedrock and the mechanism of its water-retaining performance, key geological information types directly related to the water-retaining effect of the wind-oxidation zone were screened from multi-dimensional geological information. Among them, the key geological information types directly related to the water-retaining effect of the wind-oxidation zone include the thickness of the bedrock wind-oxidation zone, the proportion of sandstone and mudstone in the wind-oxidation zone, the saturated water absorption rate of the rock, the equivalent permeability coefficient of the rock in the wind-oxidation zone, the rock quality index RQD, the rock and soil strength of the wind-oxidation zone, and the degree of wind oxidation.

[0034] S3. For the selected multivariate geological information of different order of magnitude and units of measurement, a standardized formula is used to unify the dimensions and eliminate interference caused by data differences. The standardization process uses the following formula: X ib =±(X i -X m ) / (X max -X min (where X) ib X is the standardized value of measured geological data at any location. max To evaluate the maximum value of this type of geological data within the evaluation area, X min To evaluate the minimum value of this type of geological data within the area, X i To evaluate the measured value of this type of geological data at any location within the evaluation area, X m The median value is used as the background value for this type of geological data in the evaluation area, unless there is no background value. A plus sign is used when the geological data being evaluated is correlated with a positive anomaly, and a minus sign is used when the geological data being evaluated is correlated with a negative anomaly.

[0035] S4. An improved CRITIC weighting method is used to calculate the weight values ​​for various types of geological information. The weight values ​​are determined based on data volatility and index correlation. For the same geographical location, standardized multivariate geological data are weighted and superimposed with their corresponding weights to obtain the superimposed values. The improved CRITIC weighting method calculates the weights by: characterizing volatility through the ratio of the data standard deviation to the median (greater volatility results in a higher weight); calculating the correlation between different types of geological information (lower correlation results in a higher weight); and finally determining the weight values ​​based on the combined volatility and correlation, with the sum of the weight values ​​for all geological information types being 1. The coefficient of variation C is used to... Vj =σj / Medianj calculates data volatility, where σj is the standard deviation of the j-th type of geological data, Medianj is the median of the j-th type of geological data, and combines it with the index conflict R=C Vj The weights are calculated using the formula × (1-r(k)), where r(k) is the correlation coefficient between the j-th type of geological data and other geological data. The weighted overlay integration uses the formula: X d =W1X i b1+W2X i b2+W3X i b3+……+W i X i b i Among them, X d X represents the summed values. i b i Let W be the standardized value of the i-th type of geological data. i W represents the weight of the i-th type of geological data. i The value ranges from 0 to 1, and the smaller the correlation and the greater the volatility between geological data types, the larger the value of Wi.

[0036] S5. Draw contour maps based on the distribution characteristics of the superimposed values, classifying the barrier effect of the wind-oxidized zone at the top of the bedrock on the loose water body into four levels: excellent, good, poor, and very poor. Then, use Surfer or ArcGIS software to draw X... d The contour map is filled with different colors according to the level to form a comprehensive evaluation map of the water-blocking effect. The standard for classifying the barrier effect level is as follows:

[0037] Advantages: X d A value greater than 0.6 indicates an intact wind oxidation zone structure and strong water-resistant performance.

[0038] Good:X d The value is between 0.3 and 0.6, the wind oxidation zone structure is relatively complete, and the water-proof performance is strong.

[0039] Poor: X d The value is between -0.3 and 0.3, indicating that the wind oxidation zone has localized crack development and its water-proofing performance is generally poor.

[0040] Difference: X d If the value is less than -0.3, the wind oxidation zone structure is broken and the water-proof performance is weak.

[0041] Further, background: The 1012 working face of Suntuan Coal Mine is the key mining area of ​​the mine. There is a wind oxidation zone on the top of the bedrock between the coal seam roof and the loose aquifer. It is necessary to evaluate its water-blocking performance to guide the setting of sand-prevention coal pillars and water hazard prevention work.

[0042] Specific steps: S1: Data collection and analysis of the distribution characteristics of the wind-oxidized zone. Collect various geological results for the evaluation area, including: Geological exploration data: data from 20 boreholes, core descriptions, rock mechanical properties, etc. Geophysical data: resistivity data and seismic wave velocity. Geochemical data: rock elemental analysis. Remote sensing image data: the distribution range of sparse surface vegetation roughly coincides with that of the wind-oxidized zone.

[0043] Next, through multi-source data integration, it was determined that the wind oxidation zone of the working face is generally thicker in the east and thinner in the west, with a thickness of 6-8m in the east and 2-4m in the west. The lateral continuity is moderate, and there are local areas with fracture development.

[0044] S2: Screening of Key Geological Information. Based on distribution characteristics and water-blocking mechanisms, key indicators were screened as follows: thickness of the bedrock weathering zone (H); proportion of sandstone and mudstone within the weathering zone (S, 70%–85% in the east, 50%–65% in the west); saturated water absorption rate of the rock (W, 39%–50% for strongly weathered mudstone); and equivalent permeability coefficient (K, 1.2 × 10⁻⁶ within the weathering zone). -6 ~5.0×10 -5 cm / s). Rock quality index RQD (RQD 10%~30% for strongly weathered sections, 40%~60% for weakly weathered sections). Degree of wind oxidation (F, assigned according to weathering grade: strongly weathered = 1, weakly weathered = 2, unweathered = 3).

[0045] S3: Data Standardization Processing: Taking the thickness of the wind-oxidized zone as an example, X max =8m, X min =2m, median X m =5m, the actual measured thickness of a certain borehole is 6m, then X ib = (6-5) / (8-2) = 0.17. The standardized values ​​of some indicators are as follows:

[0046] index Eastern region average Western region average Thickness H normalized value 0.33 -0.17 S-standardized value of sandstone and mudstone proportion 0.42 0.15 Saturated water absorption rate W (standardized value) -0.35 -0.20 Standardized value of permeability coefficient K -0.28 -0.12 RQD Standardized Value 0.25 0.10 Wind oxidation degree F-standardized value 0.20 0.30

[0047] S4: Weighted Overlay Integration. An improved CRITIC weighting method is used to calculate weights: Data volatility: Permeability coefficient K has a coefficient of variation CV = 0.65 (maximum), indicating a high weighting. Indicator correlation: Wind oxidation degree F has a correlation r = 0.2 (minimum) with other indicators, indicating a high weighting.

[0048] The final weight allocation is as follows:

[0049] index H S W K RQD F <![CDATA[Weight W i > 0.15 0.18 0.20 0.22 0.10 0.15

[0050] Eastern region after superposition calculation: X d =0.15×0.33+0.18×0.42+0.20×(-0.35)+0.22×(-0.28)+0.10×0.25+0.15×0.20=0.42

[0051] Western region: Xd = 0.15 × (-0.17) + 0.18 × 0.15 + 0.20 × (-0.20) + 0.22 × (-0.12) + 0.10 × 0.10 + 0.15 × 0.30 = -0.05

[0052] S5: Hierarchical Classification and Visualization. Eastern Region X d =0.42, which is considered "good". The wind oxidation zone structure is relatively complete and has strong water-proof performance.

[0053] Western Region X d =-0.05, which is classified as "poor" level, indicating the presence of localized cracks and generally poor water-proofing performance.

[0054] Example 2,

[0055] Evaluation of the water-blocking effect of a complex geological unit in the eastern mining area

[0056] Background: This unit is affected by fault structures, and the wind oxidation zone is significantly disturbed by tectonic activity. Accurate evaluation of differences in water-tightness performance is required to optimize prevention and control measures.

[0057] Key differences: S1: Data characteristics. The thickness of the aeolian oxide zone near the fault zone changes abruptly, and the resistivity is abnormally low. Geochemical data show active elemental migration in the fault zone, with Na⁺ and K⁺ contents 20%–40% higher than in normal areas.

[0058] S2: Index Adjustment: Added "Fault Influence Distance (D)" index (0-50m, the value is smaller the closer to the fault).

[0059] S4: Weighting and Overlay: Distance of Fault Influence D and Weight W i =0.25, CV=0.7 due to extremely low correlation with other indicators. X near the fault zone d =-0.45, belonging to the "poor" level, far from the fault zone X d =0.72, which is considered "excellent".

[0060] Evaluation results: Drainage boreholes need to be increased near the fault zone, while the width of the coal pillar can be appropriately reduced away from the fault zone.

[0061] Example 3,

[0062] Examples of water hazard prevention and control applications based on evaluation results

[0063] Application Process: In superior-grade areas, conventional coal pillars are used, with quarterly inspections. In good-grade areas, the coal pillar width is increased to 12m, with monthly inspections and two additional verification boreholes. In poor-grade areas, the coal pillar width is 15m, with weekly inspections and five drainage holes. Mining in poor-grade areas is suspended until grouting reinforcement is implemented, followed by a reassessment. Mining resumes only after the standards are met.

[0064] Application results: Through differentiated prevention and control, the efficiency of annual water hazard investigation was increased by 40%, the resource recovery rate was increased by 8%, and no sudden water accidents occurred.

[0065] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock, characterized in that, The evaluation method is as follows: S1. Collect and analyze existing geological results in the evaluation area, and determine the spatial distribution range, thickness variation and lateral continuity characteristics of the wind oxidation zone at the top of the bedrock in the evaluation area through multi-source data integration; S2. Then, based on the distribution characteristics of the wind oxidation zone at the top of the bedrock and the mechanism of its water-retaining performance, key geological information types directly related to the water-retaining effect of the wind oxidation zone were screened from multi-dimensional geological information. S3. For the selected multivariate geological information of different order of magnitude and different units of measurement, a standardized formula is used to unify the dimensions and eliminate the interference caused by data differences. S4. The improved CRITIC weighting method is used to calculate the weight values ​​of various geological information. The weight values ​​are determined based on data volatility and index correlation. For the same geographical location, the standardized multivariate geological data and the corresponding weights are weighted and superimposed to obtain the superimposed values. S5. Draw contour maps based on the distribution characteristics of superimposed values, classify the barrier effect of the wind oxidation zone at the top of the bedrock on the loose water body into four levels: excellent, good, poor, and very poor, and form a visual comprehensive evaluation map.

2. The method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock according to claim 1, characterized in that, In S1, the existing geological results in the evaluation area include geological exploration data, geophysical data, geochemical data, and remote sensing image data. Among them, geological exploration data includes borehole data, core descriptions, and rock mechanical properties; geophysical data includes resistivity, spontaneous potential, and seismic wave velocity; geochemical data is used to analyze the distribution and migration patterns of elements in rocks; and remote sensing image data is used to provide information on landform and vegetation cover.

3. The method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock according to claim 1, characterized in that, In S2, the key geological information types directly related to the water-blocking effect of the wind oxidation zone include the thickness of the bedrock wind oxidation zone, the proportion of sandstone and mudstone in the wind oxidation zone, the saturated water absorption rate of the rock, the equivalent permeability coefficient of the rock in the wind oxidation zone, the rock quality index RQD, the rock and soil strength of the wind oxidation zone, and the degree of wind oxidation.

4. The method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock according to claim 1, characterized in that, In S3, the normalization process uses the following formula: X ib =±(X i -X m ) / (X max -X min (where X) ib X is the standardized value of measured geological data at any location. max To evaluate the maximum value of this type of geological data within the evaluation area, X min To evaluate the minimum value of this type of geological data within the area, X i To evaluate the measured value of this type of geological data at any location within the evaluation area, X m To evaluate the background values ​​of this type of geological data in the area, the median value is used when there are no background values.

5. The method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock according to claim 4, characterized in that, When the geological data involved in the evaluation is correlated with a positive anomaly, a plus sign is used; when the geological data involved in the evaluation is correlated with a negative anomaly, a minus sign is used.

6. The method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock according to claim 1, characterized in that, In S4, the improved CRITIC weighting method calculates weights by: characterizing volatility by the ratio of the data standard deviation to the median; the greater the volatility, the higher the weight percentage; then calculating the correlation between different geological information types; the smaller the correlation, the higher the weight percentage; finally, determining the weight value based on the comprehensive volatility and correlation, and the sum of the weight values ​​for all geological information types is 1.

7. The method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock according to claim 6, characterized in that, Through the coefficient of variation C Vj =σj / Medianj calculates data volatility, where σj is the standard deviation of the j-th type of geological data, Medianj is the median of the j-th type of geological data, and combines it with the index conflict R=C Vj The weight is calculated as ×(1-r(k)), where r(k) is the correlation coefficient between the j-th type of geological data and other geological data.

8. The method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock according to claim 6, characterized in that, In S4, the weighted superposition integration uses the formula: X d =W1X i b1+W2X i b2+W3X i b3+……+W i X i b i Among them, X d X represents the summed values. i b i Let W be the standardized value of the i-th type of geological data. i W represents the weight of the i-th type of geological data. i The value ranges from 0 to 1, and the smaller the correlation and the greater the volatility between geological data types, the larger the value of Wi.

9. The method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock according to claim 1, characterized in that, In S5, the standard for classifying barrier effectiveness levels is as follows: Advantages: X d A value greater than 0.6 indicates an intact wind oxidation zone structure and strong water-resistant performance; Good:X d The value is between 0.3 and 0.6, the wind oxidation zone structure is relatively complete, and the water-proof performance is strong; Poor: X d The value is between -0.3 and 0.3, indicating that the wind oxidation zone has localized crack development and its water-proofing performance is generally poor. Difference: X d If the value is less than -0.3, the wind oxidation zone structure is broken and the water-proof performance is weak.

10. The method for evaluating the water-retaining effect of the wind-oxidized zone at the top of bedrock according to claim 1, characterized in that, In S5, visualization is achieved by drawing X using Surfer or ArcGIS software. d The contour lines are filled with different colors according to their levels to form a comprehensive evaluation map of the waterproofing effect.

Images