Method for confirming infiltration recharge position and amount of loose aquifer

Abstract

The application discloses a loose aquifer infiltration recharge position and infiltration amount confirmation method, and specifically implements the following steps: step 1, selecting each water level observation hole drawdown value; step 2, selecting a solution area of the infiltration recharge position; step 3, carrying out grid division on the solution area selected in step 2; step 4, calculating the distance between each grid division area center point and each water level observation hole; step 5, taking each grid division area center point as the infiltration recharge position, and calculating the corresponding infiltration recharge amount of each grid division area; step 6, calculating the variance of the corresponding infiltration recharge amount of each grid division area; and step 7, calculating the infiltration recharge position based on the minimum variance. The loose aquifer infiltration recharge position and infiltration amount confirmation method solves the problem that the infiltration recharge position and the infiltration recharge amount of the loose layer are difficult to accurately confirm, and greatly reduces the investment of hydrogeological exploration work.

Description

Technical Field

[0001] This invention belongs to the technical field of hydrogeological exploration methods, and relates to a method for confirming the location and amount of infiltration recharge in loose aquifers. Background Technology

[0002] Coal-bearing strata are often formed by tectonic and sedimentary processes, resulting in the deposition of a loose layer on top. Before the formation of rock, this loose layer has a high porosity and, under the influence of atmospheric precipitation, often contains a large amount of groundwater, providing a high-quality water source for humans. However, this poses a safety hazard to the coal mining process. Although an aquitard is often developed at the bottom of the loose aquitard, there are gaps in some areas. These gaps become the recharge points for the loose aquitard to the coal-bearing strata. Due to the strong water-bearing capacity of the loose aquitard, mining coal resources at and near the recharge points faces a huge risk of water damage. Therefore, it is necessary to grout and seal these locations before mining.

[0003] Existing technology involves exploring recharge locations through drilling, but this method has several drawbacks: for small-scale recharge locations, conventional 500m spacing drilling is difficult to control, and increasing the drilling density would incur huge costs. Therefore, accurately determining the location is a very costly task. It is necessary to use other methods to determine the recharge location and provide a target for addressing water hazards caused by loose layer infiltration. Summary of the Invention

[0004] The purpose of this invention is to provide a method for confirming the infiltration recharge location and infiltration amount of loose aquifers, which solves the problem of accurately confirming the infiltration recharge location and infiltration recharge amount of loose aquifers, and at the same time greatly reduces the investment in hydrogeological exploration.

[0005] The technical solution adopted in this invention is a method for confirming the infiltration recharge location and infiltration volume of loose aquifers, which is implemented according to the following steps:

[0006] Step 1: Select the drawdown values ​​for each water level observation well;

[0007] Step 2: Select the solution region for the infiltration recharge location;

[0008] Step 3: Mesh the solution domain selected in Step 2;

[0009] Step 4: Calculate the distance between the center point of each segmented region and each water level observation well;

[0010] Step 5: Using the center point of each segmented region as the infiltration recharge location, calculate the infiltration recharge amount corresponding to each segmented region;

[0011] Step 6: Calculate the variance of infiltration recharge for each segmented region;

[0012] Step 7: Calculate the infiltration recharge location based on minimum variance.

[0013] The invention is further characterized in that,

[0014] Step 1 is as follows:

[0015] The water level drop of each well within the same time period is selected, and the water level change curve shows a single downward trend. The water level drop of each well is denoted as F. j j = 1 to m, where m is the total number of water level observation wells, and the coordinates of the water level observation wells are (G jx G jy ), where G jx Let G be the X coordinate of the j-th water level observation well. jy Let Y be the Y coordinate of the j-th water level observation well.

[0016] The solution area for infiltration recharge location is determined as follows: the outermost boundary of each water level observation well is extended outward by 2-3 km, and each water level observation well yields a circular extension area, resulting in multiple extension areas. Then, based on the multiple extension areas, a specific rectangular area is determined as the solution area for infiltration recharge location. This rectangular area is within the set formed by the multiple extension areas and includes the boundary of the hydrogeological unit and the water level observation well.

[0017] Step 3 specifically involves:

[0018] The solution region selected in step 2 is divided into multiple partitioned regions using an equal-interval method, with an interval of 50–100 m. The coordinates (x, y, y) of the center point of each partitioned region are then calculated. i y i ), where i = 1 to n, n is the number of partitioned regions, x i Only the X and Y coordinates of the i-th partitioned region are given. i Let Y be the Y coordinate of the i-th segmented region.

[0019] In step 4, the distance between the center point of each segmented region and each water level observation well is calculated using the following formula:

[0020] L ij =((G jx -x i )+(G jy -y i )) 0.5 (Equation 1).

[0021] Step 5 involves calculating the infiltration recharge for each segmented region as follows:

[0022] Taking each area as the infiltration recharge location, the infiltration recharge of that area is calculated by arbitrarily selecting the drawdown of two water level observation wells. The corresponding calculation for each area is then performed. The amount of infiltration replenishment is denoted as Q. ia The unit is m. 3 / d represents the infiltration recharge amount corresponding to the a-th segmented region.

[0023]

[0024] Where K is the permeability coefficient, in m / d; and M is the aquifer thickness, in m.

[0025] In step 6, the variance of the infiltration recharge corresponding to each segmented region is calculated using the following formula:

[0026]

[0027] Wherein, V(Q) i ) Calculated for each region The average value of each infiltration replenishment.

[0028] Step 7 specifically includes:

[0029] Compare the S calculated for each partitioned region 2 (Q i If the center point of the partitioned region with the smallest variance is taken as the final determined infiltration recharge location, then the final infiltration recharge amount Q is... t This corresponds to the partition region with the smallest variance value. The average of each infiltration replenishment amount is:

[0030]

[0031] Among them, Q t The unit is m 3 / d.

[0032] The beneficial effects of this invention are:

[0033] This invention eliminates the need for intensive, large-scale hydrogeological exploration projects to obtain the location of infiltration recharge in the loose layer. Instead, it utilizes only water level drawdown data from wellbore observations to accomplish the aforementioned tasks. Based on the water level drawdown of each well, this invention calculates the infiltration recharge amount corresponding to each potential infiltration recharge area. Areas where the calculated infiltration recharge amounts based on the drawdown of each well are equal are designated as infiltration recharge locations in the loose layer. Variance is used to evaluate the degree of equality in infiltration recharge amounts; a smaller variance indicates a higher probability of it being an infiltration recharge location. The average calculated value of each infiltration recharge amount is taken as the recharge amount for that location. This method significantly reduces the investment in hydrogeological exploration while enabling more accurate acquisition of the location and amount of infiltration recharge in the loose layer, making the sealing of infiltration recharge locations more targeted and achieving more significant treatment effects. Attached Figure Description

[0034] Figure 1 This is a flowchart of the method for confirming the location and amount of infiltration recharge in loose aquifers according to the present invention;

[0035] Figure 2 This is a diagram of the solution region for the selected infiltration recharge location in Example 3 of this embodiment;

[0036] Figure 3 This is the mesh partition diagram of the solution region in Example 3. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0038] Example 1

[0039] The present invention provides a method for confirming the location and amount of infiltration recharge in loose aquifers, the process of which is as follows: Figure 1 As shown, the specific steps are as follows:

[0040] Step 1: Select the drawdown values ​​for each water level observation well. Specifically, select the water level drop of each water level observation well within the same time period, where the water level change curve shows a single downward trend, and denote the water level drop of each water level observation well as F. j j = 1 to m, where m is the total number of water level observation wells, and the coordinates of the water level observation wells are (G jx G jy ), where G jx Let G be the X coordinate of the j-th water level observation well. jy Let Y be the Y coordinate of the j-th water level observation well.

[0041] Step 2: Select the solution area for the infiltration recharge location. The solution area for the infiltration recharge location is determined as follows: Extend the outermost boundary of each water level observation well outward by 2-3 km. Each water level observation well will have a circular extension area, resulting in multiple extension areas. Then, based on the multiple extension areas, determine a specific rectangular area as the solution area for the infiltration recharge location. This rectangular area is within the set formed by the multiple extension areas and includes the boundary of the hydrogeological unit and the water level observation well.

[0042] Step 3: Mesh the solution region selected in Step 2. Specifically, divide the solution region selected in Step 2 into multiple partitioned regions using an equal-interval method, and calculate the coordinates (x, y) of the center point of each partitioned region. i y i ), where i = 1 to n, n is the number of partitioned regions, x i Only the X and Y coordinates of the i-th partitioned region are given. i Let Y be the Y coordinate of the i-th partitioned region;

[0043] Step 4: Calculate the distance between the center point of each segmented region and each water level observation well; the distance between the center point of each segmented region and each water level observation well is calculated using the following formula:

[0044] L ij =((G jx -x i )+(G jy -y i )) 0.5 (Formula 1);

[0045] Step 5: Using the center point of each segmented region as the infiltration recharge location, calculate the infiltration recharge amount corresponding to each segmented region; the calculation of the infiltration recharge amount corresponding to each segmented region is carried out in the following manner:

[0046] Taking each area as the infiltration recharge location, the infiltration recharge of that area is calculated by arbitrarily selecting the drawdown of two water level observation wells. The corresponding calculation for each area is then performed. The amount of infiltration replenishment is denoted as Q. ia The unit is m. 3 / d represents the infiltration recharge amount corresponding to the a-th segmented region.

[0047]

[0048] Where K is the permeability coefficient, in m / d; M is the aquifer thickness, in m;

[0049] Step 6: Calculate the variance of infiltration recharge for each segmented region. The specific formula for calculating the variance of infiltration recharge for each segmented region is as follows:

[0050]

[0051] Wherein, V(Q) i ) Calculated for each region The average value of each infiltration replenishment;

[0052] Step 7, calculate the infiltration recharge location based on minimum variance, specifically as follows:

[0053] Compare the S calculated for each partitioned region 2 (Q i If the center point of the partitioned region with the smallest variance is taken as the final determined infiltration recharge location, then the final infiltration recharge amount Q is... t This corresponds to the partition region with the smallest variance value. The average of each infiltration replenishment amount is:

[0054]

[0055] Among them, Q t The unit is m 3 / d.

[0056] Example 2

[0057] The method for confirming the infiltration recharge location and infiltration volume of loose aquifers according to the present invention is implemented according to the following steps:

[0058] Step 1: Select the drawdown values ​​for each water level observation well. Specifically, select the water level drop of each water level observation well within the same time period, where the water level change curve shows a single downward trend, and denote the water level drop of each water level observation well as F. j j = 1 to m, where m is the total number of water level observation wells, and the coordinates of the water level observation wells are (G jx G jy ), where G jx Let G be the X coordinate of the j-th water level observation well. jy Let Y be the Y coordinate of the j-th water level observation well.

[0059] Step 2: Select the solution region for the infiltration recharge location. The specific method for selecting the solution region is as follows: Extend the outermost boundary of each water level observation well outwards by 2-3 km, resulting in a circular extension region for each well. Multiple extension regions are then determined. Based on these multiple extension regions, a specific rectangular region is selected as the solution region for the infiltration recharge location. This rectangular region is within the total set formed by the multiple extension regions and includes the boundaries of the hydrogeological unit and the water level observation wells. Figure 2 As shown;

[0060] Step 3: The solution region selected in Step 2 is meshed. Specifically, the solution region is divided into equal-interval regions. Smaller intervals result in higher accuracy of the calculated infiltration recharge location, but also increase the computational load. Typically, an interval of 50–100 m is used to obtain multiple meshed regions. The coordinates (x, y, y) of the center point of each meshed region are then calculated. i y i ), where i = 1 to n, n is the number of partitioned regions, x i Only the X and Y coordinates of the i-th partitioned region are given. i Let Y be the Y coordinate of the i-th partitioned region;

[0061] Step 4: Calculate the distance between the center point of each segmented region and each water level observation well; the distance between the center point of each segmented region and each water level observation well is calculated using the following formula:

[0062] L ij =((G jx -x i )+(G jy -y i )) 0.5 (Formula 1);

[0063] Step 5: Using the center point of each segmented region as the infiltration recharge location, calculate the infiltration recharge amount corresponding to each segmented region; the calculation of the infiltration recharge amount corresponding to each segmented region is carried out in the following manner:

[0064] Taking each area as the infiltration recharge location, the infiltration recharge of that area is calculated by arbitrarily selecting the drawdown of two water level observation wells. The corresponding calculation for each area is then performed. The amount of infiltration replenishment is denoted as Q. ia The unit is m. 3 / d represents the infiltration recharge amount corresponding to the a-th segmented region.

[0065]

[0066] Where K is the permeability coefficient, in m / d; M is the aquifer thickness, in m;

[0067] Step 6: Calculate the variance of infiltration recharge for each segmented region. The specific formula for calculating the variance of infiltration recharge for each segmented region is as follows:

[0068]

[0069] Wherein, V(Q) i ) Calculated for each region The average value of each infiltration replenishment;

[0070] Step 7, calculate the infiltration recharge location based on minimum variance, specifically as follows:

[0071] Compare the S calculated for each partitioned region 2 (Q i If the center point of the partitioned region with the smallest variance is taken as the final determined infiltration recharge location, then the final infiltration recharge amount Q is... t This corresponds to the partition region with the smallest variance value. The average of each infiltration replenishment amount is:

[0072]

[0073] Among them, Q t The unit is m 3 / d.

[0074] Example 3

[0075] Step 1: Select the drawdown values ​​for each water level observation well;

[0076] In this embodiment, three surface water level observation wells in the loose layer were selected for the study area. The coordinates of each well are shown in the table below. Data from one water level drop were selected, with water level drops of 21.12m, 15.89m, and 3.67m for each well. The coordinates and drawdown depths of each well are shown in Table 1.

[0077] Table 1. Coordinates and Descent of Each Observation Hole

[0078] Observation hole number X coordinate Y coordinate Drawdown (m) Observation hole 1 26592 31460 21.12 Observation hole 2 26923 32173 15.89 Observation hole 3 25970 30364 3.67

[0079] Step 2: Select the solution region for the infiltration recharge location. The specific method for selecting the solution region is as follows: Extend the outermost boundary of each water level observation well outwards by 2.3 km, resulting in a circular extension region for each well. Multiple extension regions are then determined. Based on these multiple extension regions, a specific rectangular region is selected as the solution region for the infiltration recharge location. This rectangular region is within the complete set formed by the multiple extension regions and includes the boundaries of the hydrogeological units and the water level observation wells. The selection result is as follows: Figure 2 As shown;

[0080] Step 3: Mesh the solution domain selected in Step 2. The meshing result is as follows: Figure 3 As shown, specifically: the solution area selected in step 2 was divided into 3603 areas, including observation wells, numbered 1 to 3063, by a method of equal spacing of 100m. The center coordinates of each area were obtained.

[0081] Step 4: Calculate the distance between the center point of each segmented region and each water level observation well; the distance between the center point of each segmented region and each water level observation well is calculated using the following formula:

[0082] L ij =((G jx -x i )+(G jy -y i )) 0.5 (Formula 1);

[0083] The calculation results are shown in Table 2:

[0084] Table 2. Distance between the center point of each segmented region and each water level observation well.

[0085]

[0086] Step 5: Using the center point of each segmented region as the infiltration recharge location, calculate the infiltration recharge amount corresponding to each segmented region; the calculation of the infiltration recharge amount corresponding to each segmented region is carried out in the following manner:

[0087] Taking each area as the infiltration recharge location, the infiltration recharge of that area is calculated by arbitrarily selecting the drawdown of two water level observation wells. The corresponding calculation for each area is then performed. The amount of infiltration replenishment is denoted as Q. ia The unit is m. 3 / d represents the infiltration recharge amount corresponding to the a-th segmented region.

[0088]

[0089] Where K is the permeability coefficient, in m / d; M is the aquifer thickness, in m;

[0090] In this embodiment, the infiltration recharge was calculated based on the drawdown of the two observation wells and the center point between the observation wells and the assumed infiltration recharge location. Three infiltration recharge results should be calculated for each segmented region. The calculation results are shown in Table 3.

[0091] Table 3 shows the infiltration recharge calculated based on the assumed infiltration recharge point at the center of each segmented region.

[0092]

[0093] Step 6: Calculate the variance of infiltration recharge for each segmented region. The specific formula for calculating the variance of infiltration recharge for each segmented region is as follows:

[0094]

[0095] Wherein, V(Q) i ) Calculated for each region The average value of each infiltration replenishment;

[0096] The calculation results are shown in Table 4:

[0097] Table 4 shows the variance of infiltration recharge calculated using the assumed infiltration recharge point as the center point of each segmented region.

[0098]

[0099]

[0100] Step 7, calculate the infiltration recharge location based on minimum variance, specifically as follows:

[0101] Compare the S calculated for each partitioned region 2 (Q i If the center point of the partitioned region with the smallest variance is taken as the final determined infiltration recharge location, then the final infiltration recharge amount Q is... t This corresponds to the partition region with the smallest variance value. The average of each infiltration replenishment amount is:

[0102]

[0103] Among them, Q t The unit is m 3 / d;

[0104] In this embodiment, the variance calculation results show that the infiltration recharge variance corresponding to region 1478 is the smallest, reflecting that when this region is the assumed infiltration recharge point, the calculated infiltration recharge is basically the same. That is, this region is the infiltration recharge location, with coordinates X = 25655.79, Y = 32065.1, and its infiltration recharge is 6210.47 m³. 3 / d, which is 258.769m 3 / h.

Claims

1. A method for confirming the location and amount of infiltration recharge in loose aquifers, characterized in that, The specific steps are as follows: Step 1: Select the drawdown values ​​for each water level observation well; Step 2: Select the solution region for the infiltration recharge location; Step 3: Mesh the solution domain selected in Step 2; Step 4: Calculate the distance between the center point of each segmented region and each water level observation well; Step 5: Using the center point of each segmented region as the infiltration recharge location, calculate the infiltration recharge amount corresponding to each segmented region; The calculation of the infiltration recharge corresponding to each segmented region is performed in the following manner: Taking each area as the infiltration recharge location, the infiltration recharge of that area is calculated by arbitrarily selecting the drawdown of two water level observation wells. The corresponding calculation for each area is then performed. The amount of infiltration recharge is denoted as... The unit is m. 3 / d represents the a-th infiltration recharge amount corresponding to the i-th partitioned region, where a=1~ ; Where K is the permeability coefficient, in m / d; M is the aquifer thickness, in m; The distance between the center point of each segmented region and each water level observation well is defined as i = 1 to n, where n is the number of segmented regions. F j Let be the water level drop of the j-th water level observation well; j = 1 ~ m, where m is the total number of water level observation wells; Step 6: Calculate the variance of infiltration recharge for each segmented region; Step 7: Calculate the infiltration recharge location based on minimum variance.

2. The method for confirming the infiltration recharge location and infiltration volume of loose aquifers according to claim 1, characterized in that, Step 1 specifically involves: The water level drop of each well within the same time period was selected, and the water level change curve showed a single downward trend. The water level drop of each well was recorded as follows: F j j=1~m, where m is the total number of water level observation wells, and the coordinates of the water level observation wells are ( G jx , G jy ),in, G jx Let X be the X coordinate of the j-th water level observation well. G jy Let Y be the Y coordinate of the j-th water level observation well.

3. The method for confirming the infiltration recharge location and infiltration volume of loose aquifers according to claim 2, characterized in that, The specific method for determining the infiltration recharge location solution area is as follows: the outermost boundary of each water level observation well is extended outward by 2-3 km, and each water level observation well obtains a circular extension area, resulting in multiple extension areas. Then, based on the multiple extension areas, a specific rectangular area is determined as the infiltration recharge location solution area. This rectangular area is within the set formed by the multiple extension areas and includes the boundary of the hydrogeological unit and the water level observation well.

4. The method for confirming the infiltration recharge location and infiltration volume of loose aquifers according to claim 3, characterized in that, Step 3 specifically involves: The solution region selected in step 2 is divided into multiple partitioned regions using an equidistant method. The coordinates of the center point of each partitioned region are calculated. x i , y i ), where i = 1 to n, and n is the number of partitioned regions, x i Let the X coordinate of the i-th partitioned region be... y i Let Y be the Y coordinate of the i-th segmented region.

5. The method for confirming the infiltration recharge location and infiltration volume of loose aquifers according to claim 4, characterized in that, The time interval for partitioning is 50~100m using equal spacing.

6. The method for confirming the infiltration recharge location and infiltration volume of loose aquifers according to claim 4, characterized in that, In step 4, the distance between the center point of each segmented region and each water level observation well is calculated using the following formula: (Equation 1).

7. The method for confirming the infiltration recharge location and infiltration volume of loose aquifers according to claim 6, characterized in that, In step 6, the variance of the infiltration recharge corresponding to each segmented region is calculated using the following formula: in, Calculated for each region The average value of each infiltration replenishment.

8. The method for confirming the infiltration recharge location and infiltration volume of loose aquifers according to claim 7, characterized in that, Step 7 specifically involves: Comparison of calculations for each partitioned region If the center point of the segmented region with the smallest variance is taken as the final determined infiltration recharge location, then the final infiltration recharge amount will be... This corresponds to the partition region with the smallest variance value. The average of each infiltration replenishment amount is: in, The unit is m 3 / d.

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