CN115616188A - Construction method of two-dimensional heterogeneous aqueous medium physical model - Google Patents
Construction method of two-dimensional heterogeneous aqueous medium physical model Download PDFInfo
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- 239000012736 aqueous medium Substances 0.000 title claims abstract description 34
- 238000010276 construction Methods 0.000 title claims description 6
- 230000035699 permeability Effects 0.000 claims abstract description 127
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 101
- 238000004088 simulation Methods 0.000 claims abstract description 50
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 47
- 239000006004 Quartz sand Substances 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 23
- 239000002689 soil Substances 0.000 claims abstract description 23
- 238000005070 sampling Methods 0.000 claims abstract description 19
- 238000012360 testing method Methods 0.000 claims abstract description 17
- 239000002609 medium Substances 0.000 claims abstract description 10
- 238000005192 partition Methods 0.000 claims description 102
- 244000035744 Hura crepitans Species 0.000 claims description 29
- 230000035515 penetration Effects 0.000 claims description 11
- 230000014509 gene expression Effects 0.000 claims description 5
- 239000004816 latex Substances 0.000 claims description 4
- 229920000126 latex Polymers 0.000 claims description 4
- 239000004576 sand Substances 0.000 claims description 4
- 238000005056 compaction Methods 0.000 claims description 3
- 239000011159 matrix material Substances 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
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- 239000000463 material Substances 0.000 claims 1
- 239000003344 environmental pollutant Substances 0.000 abstract description 10
- 230000005012 migration Effects 0.000 abstract description 10
- 238000013508 migration Methods 0.000 abstract description 10
- 231100000719 pollutant Toxicity 0.000 abstract description 10
- 238000003895 groundwater pollution Methods 0.000 abstract description 3
- 238000005067 remediation Methods 0.000 abstract description 3
- 230000003204 osmotic effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 3
- 239000003673 groundwater Substances 0.000 description 3
- 239000000356 contaminant Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 229920005372 Plexiglas® Polymers 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
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- 239000010453 quartz Substances 0.000 description 1
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Abstract
The invention discloses a method for constructing a two-dimensional heterogeneous water-containing medium physical model, and belongs to the field of physical simulation of underground water flow and pollutant migration rules. Sampling a soil sample in a heterogeneous aqueous medium polluted area on site, measuring the permeability coefficient of the soil sample, and calculating the mean value and the variance of the soil sample; generating a gridded osmotic coefficient field by adopting a direct Fourier transform method; in a simulation device, filling quartz sand according to the gridded permeability coefficient field, constructing and completing a two-dimensional heterogeneous aqueous medium physical model, and reproducing the heterogeneity of the field aqueous medium. The method can truly simulate the influence of the spatial variation degree of the aqueous medium under the field condition on the migration of the pollutants, provides a more accurate physical model for the indoor test of groundwater pollution remediation, and is more suitable for the spatial variability of the actual underground aqueous medium compared with the prior method of depicting the heterogeneity of the aqueous medium by using a simple lens.
Description
Technical Field
The invention relates to the field of physical simulation of underground water flow and pollutant migration rules, in particular to a construction method of a two-dimensional heterogeneous water-containing medium physical model.
Background
Underground water resources existing in media such as soil and rocks are important resources required by human society for production and life. In recent years, the pollution of aeration zone soil and underground water caused by human activities is more serious, and the safety of ground water is threatened by sewage recharge, garbage leachate infiltration, toxic chemical liquid omission and the like. The migration and distribution of contaminants in groundwater is influenced not only by the characteristics of the source of the contamination, but also by the spatial structural characteristics of the presence medium, and therefore the spatial distribution of contaminants in groundwater is more complex than in surface water and in the atmosphere. Accurate prediction of pollutant migration behavior in an aquifer is a premise for improving groundwater pollution remediation efficiency, and heterogeneity of an aqueous medium is a key factor influencing pollutant migration. Therefore, a physical simulation test device capable of accurately simulating the migration of the heterogeneous aqueous medium pollutants is urgently needed. Most of the existing simulation test devices only adopt simple lens bodies or segment to depict the heterogeneity of aqueous media, have larger difference with the actual situation in the field, and have the defects of low simulation precision and the like. Therefore, a physical simulation device capable of more truly reproducing the heterogeneous characteristics of the field aquifer is urgently needed to be constructed, and the prediction precision of the pollutant migration behavior is improved.
Based on the method, the invention provides a method for constructing a physical model of a two-dimensional heterogeneous aqueous medium.
Disclosure of Invention
The invention aims to provide a method for constructing a two-dimensional heterogeneous aqueous medium physical model so as to solve the technical problems in the background technology.
The object of the present invention can be achieved by the following means.
A two-dimensional heterogeneous aqueous medium physical model construction method comprises the following specific steps of firstly sampling soil samples in a heterogeneous aqueous medium pollution area on site, measuring permeability coefficients of the soil samples, calculating a mean value and a variance of the soil samples, secondly generating a gridded permeability coefficient field by adopting a direct Fourier transform method, determining the permeability coefficient value of each grid, and finally filling quartz sand in a simulation device according to the gridded permeability coefficient field to construct and complete a two-dimensional heterogeneous aqueous medium physical model and reproduce the heterogeneity of a field aqueous medium:
step 1, setting of simulation device
The simulation device comprises a main body, a plurality of network partition boards A and a plurality of network partition boards B;
the main body is a rectangular box body with an opening at the upper end, and two partition plates and a water-resisting baffle plate are arranged in the rectangular box body in parallel with the left side wall and the right side wall of the box body from right to left;
the partition plates are rectangular flat plates, the height and the width of each partition plate are respectively the same as those of the left side wall and the right side wall in the inner cavity of the main body, namely the main body is divided into three independent cavities which are parallel to each other along the length direction of the main body through the two partition plates, the cavities are sequentially marked as a water inlet box, a sand box and a water drainage box from left to right, a plurality of through holes are uniformly distributed on the partition plates, three water outlets are uniformly arranged on the right side wall of the water drainage box from top to bottom at equal intervals, and each water outlet is provided with a water stop valve;
the water-stop baffle is a rectangular plate, the width of the water-stop baffle is the same as that of the partition, the height of the water-stop baffle is recorded as h2, h2 is less than h1, h1 is the height of the partition, namely, the water inlet tank is divided into a left part and a right part by the water-stop baffle, the bottom of the right part is provided with a water inlet, the bottom of the left part is provided with a water outlet, and the water inlet and the water outlet realize water inlet and water outlet of an inner cavity of the water inlet tank through a latex pipe so as to ensure the stability of a water head of the water inlet tank;
the network partition plate A and the network partition plate B are rectangular plates, the heights of the network partition plate A and the network partition plate B are recorded as the height h3 of the network partition plate, h2 is greater than h3 and is equal to or less than h1, the width of the network partition plate A is the same as the length of the inner cavity of the sand box, and the width of the network partition plate B is the same as the width of the inner cavity of the sand box; at network baffle A and network baffle B's lower part, from supreme even division of having many gaps down along the direction of height, the length in this gap is: when a plurality of network partition boards A and a plurality of network partition boards B are combined into a gridding space through the gaps in a crossed manner, the bottom surfaces of the two partition boards are kept flush;
Determining sampling points in a uniformly distributed manner in a non-homogeneous aqueous medium polluted area on site, collecting N soil samples, measuring the permeability coefficients of the N soil samples to obtain N permeability coefficient sampling values, and recording any one of the N permeability coefficient sampling values as a permeability coefficient sampling value
i is the serial number of the soil sample, i =1,2, \ 8230, N, N is a positive integer, N > 100;
calculating N permeability coefficient measurements
And are respectively recorded as mean and variance
Sum variance S 2 The expressions are respectively:
step 3, generating a permeability coefficient field
Calculating the mean value according to the step 2
Sum variance S 2 And given the number of rows R and the number of columns C of the permeability coefficient field, generating M gridded permeability coefficient fields by a direct Fourier transform method, wherein R is more than 5 and C is more than 6, namely, each permeability coefficient field contains R multiplied by C permeability coefficientsA transmission coefficient;
randomly selecting one of M permeability coefficient fields to be recorded as a permeability coefficient field gamma * In the permeability coefficient field Γ * Contains R × C permeability coefficients, and any one of them is expressed as permeability coefficient K rc R =1,2, R, C =1,2, R, C, then the permeability coefficient field Γ * Is one penetration coefficient K consisting of R multiplied by C rc A matrix of composition, whose expression is as follows:
at R × C permeability coefficients K rc In, the maximum value is taken as the maximum permeability coefficient K max Taking the minimum value and recording as the minimum value K of permeability coefficient min ；
Step 4, dividing permeability coefficient intervals
Introducing permeability coefficient field length Y, Y = K max -K min Introducing an equipartition value L, L = (K) max - K min )/J；
Equally dividing the permeability coefficient field length Y into J intervals according to the equipartition value L, and marking any one interval as an interval B j J =1, 2.. J, let the permeability coefficient at the beginning of J intervals be the permeability coefficient of the interval and be recorded as the permeability coefficient fill-in value k j ，k j ＝K min +(j-1)×L；
Dividing R x C permeability coefficients K rc Classifying the obtained values into J intervals according to the values of the obtained values, and recording the classified permeability coefficients as classified permeability coefficients
Wherein the subscript is the permeability coefficient of the class in a permeability coefficient field Γ * Is marked as the position of the classified permeability coefficient in the interval;
Spreading gauze on the partition plate to prevent quartz sand from overflowing from the through hole during the test, and then taking R-1 network partition plates A and C-1 netsA net partition board B, wherein, the R-1 block net partition board A is inserted into the bottom of the sand box along the direction vertical to the partition board, the C-1 block net partition board B is inserted into the bottom of the sand box along the direction parallel to the partition board, and the two partition boards are spliced in a relative staggered way through gaps, a cuboid space with the same volume of R x C is formed in the inner cavity of the sand box, namely, a field gamma equal to the permeability coefficient is formed in the simulation device * Middle R × C permeability coefficient K rc Corresponding R multiplied by C quartz sand filling spaces, and marking any one filling space as a filling space pi rc ；
And 6, reproducing the generated permeability coefficient field in the simulation device, and constructing a physical model
Fill value k according to J permeability coefficients j Preparing J kinds of quartz sand with permeability coefficients;
for R × C classified permeability coefficients
According to the index, the quartz sand with the corresponding permeability coefficient is marked, and the quartz sand is filled into the corresponding filling space pi in the simulation device according to the index rc Compacting, wherein the filling height of the compacting is the height h3 of the network partition plate; to-be-RxC quartz sand filling space pi rc After all the quartz sand filling spaces are filled, the R-1 network partition boards A and the C-1 network partition boards B are drawn out from the upper part and compacted again, and after compaction, the R multiplied by C quartz sand filling spaces pi rc The sand column in the quartz sand box forms a heterogeneous quartz sand simulation whole body;
during testing, the water inlet tank is used for simulating the whole body of the heterogeneous quartz sand in the sand box to inject water, after the heterogeneous quartz sand is completely saturated, one of the three water outlets is opened, and the matched water stop valve is used for adjusting the hydraulic gradient;
the simulation device formed through the steps and the quartz sand simulation whole formed in the simulation device are the two-dimensional heterogeneous water-containing medium physical model.
Preferably, the length of the sand box is L, the length of the water inlet tank is L1, the length of the drain tank is L2, L1=1/10L-1/5L, and L2 is less than or equal to L1.
Preferably, the diameter of the through holes is 0.5cm-1cm, and the number of the through holes is more than 40.
Preferably, the distance between the three water outlets is 8cm, and during a simulation test, the hydraulic gradient between the highest water outlet and the middle water outlet is 0.16, and the hydraulic gradient between the highest water outlet and the lowest water outlet is 0.32.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the sand box constructed by the invention, the interior of the sand box is divided into a plurality of sections with different permeability coefficients, and quartz sand with corresponding permeability coefficients is filled, so that the influence of the spatial variation degree of the aqueous medium under the field condition on the migration of pollutants can be simulated more truly, and a more accurate physical model is provided for an indoor test of groundwater pollution remediation;
2. according to the method, the permeability coefficient field is generated by adopting a direct Fourier transform method to depict the heterogeneity of the water-containing medium, and the generated permeability coefficient field is reproduced through a sand box test, so that the method is more suitable for the spatial variability of the actual underground water-containing medium compared with the prior method that the heterogeneity of the water-containing medium is depicted by using a simple lens body.
3. A water outlet in the simulation device is set to be an adjustable water outlet, so that hydraulic gradient can be reasonably adjusted according to actual sand filling conditions in the test process, and different test results are obtained.
Drawings
FIG. 1 is a general schematic diagram of a physical model of a two-dimensional heterogeneous aqueous medium constructed in accordance with the present invention;
FIG. 2 is a schematic view of the main body of the auxiliary device in the embodiment of the present invention;
FIG. 3 is a top view of a gridding flask in an embodiment of the present invention;
FIG. 4 is a schematic structural view of a separator in an embodiment of the invention;
FIG. 5 is a schematic diagram of the structure of network partition A/network partition B in an embodiment of the present invention;
in the figure: 1. a main body; 2. a water discharge port; 3. a latex tube; 4. a water inlet; 5. a water-stop baffle; 6. a partition plate; 7. filling space pi rc (ii) a 8. A water outlet; 9. a water stop valve; 10. a quartz sand column; 11. a water inlet tank; 12. A sand box; 13. row boardA water tank; 14. a through hole; 15. a network separator A; 16. a network partition B; 17. a gap.
Detailed Description
The invention will be described more fully below with reference to the accompanying drawings.
The invention provides a construction method of a two-dimensional heterogeneous aqueous medium physical model, which comprises the steps of firstly sampling soil samples in a heterogeneous aqueous medium pollution area on site, measuring permeability coefficients of the soil samples, calculating mean values and variance of the soil samples, secondly generating a gridded permeability coefficient field by adopting a direct Fourier transform method, determining the permeability coefficient value of each grid, and finally filling quartz sand in a simulation device according to the gridded permeability coefficient field to construct and complete the two-dimensional heterogeneous aqueous medium physical model and reproduce the heterogeneity of a field aqueous medium.
The method comprises the following specific steps:
step 1, setting simulation device
The simulation device comprises a main body 1, a plurality of network partition boards A15 and a plurality of network partition boards B16;
the main body 1 is a rectangular box body with an opening at the upper end, and two partition plates 6 and a water-resisting baffle plate 5 are arranged in the rectangular box body in parallel with the left side wall and the right side wall of the box body from right to left;
the partition plates 6 are rectangular flat plates, the height and the width of each partition plate are respectively the same as those of the left side wall and the right side wall in the inner cavity of the main body 1, namely the main body 1 is divided into three independent cavities parallel to each other along the length direction of the main body 1 by the two partition plates 6, the cavities are sequentially marked as a water inlet tank 11, a sand box 12 and a water drainage tank 13 from left to right, a plurality of through holes 14 are uniformly distributed on the partition plates 6, three water outlets 8 are uniformly arranged on the right side wall of the water drainage tank 13 from top to bottom at equal intervals, and a water stop valve 9 is arranged on each water outlet 8;
the water-stop baffle 5 is a rectangular plate, the width of the water-stop baffle 5 is the same as that of the partition plate 6, the height of the water-stop baffle 5 is recorded as h2, h2 is less than h1, h1 is the height of the partition plate 6, namely, the water inlet tank 11 is divided into a left part and a right part by the water-stop baffle 5, the bottom of the right part is provided with a water inlet 4, the bottom of the left part is provided with a water outlet 2, and the water inlet 4 and the water outlet 2 realize water inlet and water discharge to the inner cavity of the water inlet tank 11 through a latex tube 3 so as to ensure the stability of the water head of the water inlet tank 11;
the net partition plate A15 and the net partition plate B16 are both rectangular plates, the heights of the net partition plates are recorded as the height h3 of the net partition plate, h2 is more than h3 and is less than or equal to h1, the width of the net partition plate A15 is the same as the length of the inner cavity of the sand box 12, and the width of the net partition plate B16 is the same as the width of the inner cavity of the sand box 12; a plurality of gaps 17 are uniformly formed in the lower parts of the network partition board A15 and the network partition board B16 along the height direction from bottom to top, and the length of each gap 17 is as follows: when the network partition A15 and the network partition B16 are combined into a meshed space by crossing the slits 17, the bottom surfaces of the two partitions are kept flush.
FIG. 2 is a schematic view of the main body of an auxiliary device in an embodiment of the present invention, FIG. 3 is a plan view of a gridding flask in an embodiment of the present invention, FIG. 4 is a schematic view of the structure of a partition plate in an embodiment of the present invention, and FIG. 5 is a schematic view of the structure of a net partition plate A/a net partition plate B in an embodiment of the present invention.
In the present embodiment, the length of the sand box 12 is L, the length of the water inlet tank 11 is L1, the length of the drain tank 13 is L2, L1=1/10L-1/5l, and L2 is equal to or less than L1.
In the present embodiment, the diameter of the through holes 14 is 0.5cm to 1cm, and the number of the through holes 14 is greater than 40.
In this embodiment, the distances between the three water outlets 8 are all 8cm, and during the simulation test, the hydraulic gradient between the highest water outlet 8 and the middle water outlet 8 is 0.16, and the hydraulic gradient between the highest water outlet 8 and the lowest water outlet 8 is 0.32.
In this embodiment, the body 1 is made of a plexiglas plate having a thickness of 2cm, and has internal dimensions of 50cm in length, 40cm in width and 30cm in height. The height h1 of the partition plate 6 is the same as that of the main body 1, the height h2 of the water stop baffle 5 is 24cm, and the height h3 of the network partition plate A15 and the network partition plate B16 is 28cm.
Determining sampling points according to a uniform distribution mode in a site in a heterogeneous aqueous medium polluted area, collecting N soil samples, and measuring the permeability systems of the N soil samplesCounting to obtain N permeability coefficient sampling values, and recording any one of the N permeability coefficient sampling values as a permeability coefficient sampling value
i is the serial number of the soil sample, i =1, 2.., N is a positive integer, and N is more than 100;
calculating N permeability coefficient measurements
And are respectively recorded as the mean and the variance
Sum variance S 2 The expressions are respectively:
in this embodiment, the result of the sampling calculation:
S 2 ＝0.1。
step 3, generating a permeability coefficient field
Calculating the mean value according to the step 2
Sum variance S 2 Giving the row number R and the column number C of the penetration coefficient field, and generating M gridded penetration coefficient fields by adopting a direct Fourier transform method, wherein R is more than 5, C is more than 6, namely R multiplied by C penetration coefficients are contained in each penetration coefficient field;
randomly selecting one of M permeability coefficient fields to be recorded as a permeability coefficient field gamma * In the permeability coefficient field Γ * Contains R × C permeability coefficients, and any one of them is expressed as permeability coefficient K rc ，r＝1R, C =1,2, R, C, then the permeability coefficient field Γ * One penetration coefficient K is formed by R multiplied by C rc A matrix formed by the following expressions:
at R × C permeability coefficients K rc In, the maximum value is taken as the maximum permeability coefficient K max Taking the minimum value and recording as the minimum value K of permeability coefficient min 。
In this embodiment, let R =10,c =8, and the resulting permeability coefficient field is as follows:
comparing the values of the above permeability coefficients, K max ＝43.83，K min ＝12.01。
Step 4, dividing permeability coefficient intervals
Introducing permeability coefficient field length Y, Y = K max -K min Introducing an equipartition value L, L = (K) max - K rc-min )/J；
Equally dividing the permeability coefficient field length Y into J intervals according to the equipartition value L, and marking any one interval as an interval B j J =1, 2.. J, let the permeability coefficient at the beginning of J intervals be the permeability coefficient of the interval and be noted as the permeability coefficient fill-in value k j ，k j ＝K min +(j-1)×L；
Dividing R x C permeability coefficients K rc Classifying the obtained values into J intervals according to the values of the obtained values, and recording the classified permeability coefficients as classified permeability coefficients
Wherein the subscript is the permeability coefficient of the class in a permeability coefficient field Γ * Is labeled as the position of the categorised permeability coefficient in the interval.
In the present embodiment, J =9, i.e.Dividing the obtained product into 9 intervals, and calculating permeability coefficient filling values k of the 9 intervals j Respectively as follows: k is a radical of 1 ＝12.01，k 2 ＝15.55，k 3 ＝19.09，k 4 ＝22.63，k 5 ＝26.17，k 6 ＝29.71， k 7 ＝33.25，k 8 ＝36.79，k 0 ＝40.33。
Laying gauze on the partition board 6 to prevent quartz sand from overflowing from the through hole 14 during the test, then taking R-1 pieces of network partition boards A15 and C-1 pieces of network partition boards B16, wherein the R-1 pieces of network partition boards A15 are inserted into the bottom of the sand box 12 along the direction vertical to the partition board 6, the C-1 pieces of network partition boards B16 are inserted into the bottom of the sand box 12 along the direction parallel to the partition board 6, the two partition boards are relatively staggered and spliced through a gap 17, and a cuboid space with the same volume of R x C is formed in the inner cavity of the sand box 12, namely a cuboid space with the same volume as the permeability coefficient field gamma is formed in the simulation device * Medium R C permeability coefficient K rc Corresponding R multiplied by C quartz sand filling spaces, and marking any one filling space as a filling space pi rc 7。
In this example, the number of the network partition plates a15 is 9, and the number of the network partition plates B16 is 7, and 80 quartz sand filled spaces are formed in the simulation apparatus.
And 6, reproducing the generated permeability coefficient field in the simulation device, and constructing a physical model
Fill value k according to J permeability coefficients j Preparing J kinds of quartz sand with permeability coefficients;
for R × C classified permeability coefficients
According to the index, the quartz sand with the corresponding permeability coefficient is marked, and the quartz sand is filled into the corresponding filling space pi in the simulation device according to the index rc 7, compacting, wherein the filling height is the height h3 of the network partition; to-be-RxC quartz sand filling space pi rc 7, after the filling is finished, the R-1 network partition boards A15 and the C-1 network partition boards B16 are drawn out from the upper part and compacted again,and after compaction, R multiplied by C quartz sands fill the space pi rc The middle sand column 10 forms a heterogeneous quartz sand simulation whole body;
during the test, the water inlet tank 11 is used for injecting water into the heterogeneous quartz sand simulation whole in the sand box 12, after the heterogeneous quartz sand simulation whole is completely saturated, one of the three water outlets 8 is opened, and the matched water stop valve 9 is used for adjusting the hydraulic gradient.
The simulation device formed through the steps and the quartz sand simulation whole formed in the simulation device are the two-dimensional heterogeneous water-containing medium physical model. FIG. 1 shows an overall schematic diagram of a two-dimensional heterogeneous aqueous medium physical model constructed by the invention.
By utilizing the physical model, a simulation test of heterogeneous characteristics of the wild aquifer under the conditions of various pollutants and various water flows can be carried out, and the prediction precision of the pollutant migration behavior is improved.
Claims (4)
1. A two-dimensional heterogeneous aqueous medium physical model construction method is characterized in that soil samples in a heterogeneous aqueous medium pollution area are sampled on site, permeability coefficients of the soil samples are measured, mean values and variances of the soil samples are calculated, a gridded permeability coefficient field is generated by adopting a direct Fourier transform method, the permeability coefficient value of each grid is determined, finally, quartz sand filling is carried out in a simulation device according to the gridded permeability coefficient field, a two-dimensional heterogeneous aqueous medium physical model is constructed, and the heterogeneity of a field aqueous medium is reproduced, and the method specifically comprises the following steps:
step 1, setting of simulation device
The simulation device comprises a main body (1), a plurality of network partition boards A (15) and a plurality of network partition boards B (16);
the main body (1) is a rectangular box body with an opening at the upper end, and two partition plates (6) and a water-stop baffle (5) are arranged in the rectangular box body in parallel with the left side wall and the right side wall of the box body from right to left;
the partition plate (6) is a rectangular flat plate, the height and the width of the partition plate are respectively the same as those of the left side wall and the right side wall in the inner cavity of the main body (1), namely the main body (1) is divided into three independent cavities parallel to each other along the length direction of the main body (1) through the two partition plates (6), the three independent cavities are sequentially marked as a water inlet box (11), a sand box (12) and a water drainage box (13) from left to right, a plurality of through holes (14) are uniformly distributed on the partition plate (6), three water outlets (8) are uniformly arranged on the right side wall of the water drainage box (13) from top to bottom at equal intervals, and a water stop valve (9) is arranged on each water outlet (8);
the water-stop baffle (5) is a rectangular plate, the width of the water-stop baffle is the same as that of the partition (6), the height of the water-stop baffle (5) is recorded as h2, h2 is less than h1, and h1 is the height of the partition (6), namely, the water inlet tank (11) is divided into a left part and a right part through the water-stop baffle (5), a water inlet (4) is formed in the bottom of the right part, a water outlet (2) is formed in the bottom of the left part, and the water inlet (4) and the water outlet (2) realize water inlet and water outlet of the inner cavity of the water inlet tank (11) through the latex tube (3) so as to ensure the stability of the water head of the water inlet tank (11);
the net partition plate A (15) and the net partition plate B (16) are both rectangular plates, the heights of the net partition plates are recorded as the height h3 of the net partition plate, h2 is more than h3 and is less than or equal to h1, the width of the net partition plate A (15) is the same as the length of the inner cavity of the sand box (12), and the width of the net partition plate B (16) is the same as the width of the inner cavity of the sand box (12); at the lower part of network baffle A (15) and network baffle B (16), evenly open along the direction of height from the bottom up has many gaps (17), and the length of this gap (17) is: when a plurality of network partition boards A (15) and a plurality of network partition boards B (16) are combined into a gridding space in a crossed way through the gaps (17), the bottom surfaces of the two partition boards are kept flush;
step 2, sampling and calculating
Determining sampling points in a uniformly distributed manner in a non-homogeneous aqueous medium polluted area on site, collecting N soil samples, measuring the permeability coefficients of the N soil samples to obtain N permeability coefficient sampling values, and recording any one of the N permeability coefficient sampling values as a permeability coefficient sampling value
i is the serial number of the soil sample, i =1, 2.., N is a positive integer, and N is more than 100;
calculating N permeability coefficient measurements
And are respectively recorded as mean and variance
And a variance S2, expressed as:
step 3, generating a permeability coefficient field
Calculating the mean value according to the step 2
Sum variance S 2 Giving the row number R and the column number C of the penetration coefficient field, and generating M gridded penetration coefficient fields by adopting a direct Fourier transform method, wherein R is more than 5, C is more than 6, namely R multiplied by C penetration coefficients are contained in each penetration coefficient field;
randomly selecting one of M permeability coefficient fields to be recorded as a permeability coefficient field gamma * In the permeability coefficient field Γ * Contains R × C permeability coefficients, and any one of them is denoted as permeability coefficient K rc R =1, 2.. Said R, C =1, 2.. Said C, then the permeability coefficient field Γ * One penetration coefficient K is formed by R multiplied by C rc A matrix of composition, whose expression is as follows:
at R × C permeability coefficients K rc In, the maximum value is taken as the maximum permeability coefficient K max Taking the minimum value and recording as the minimum value K of permeability coefficient min ；
Step 4, dividing permeability coefficient intervals
Introducing permeability coefficient field length Y, Y = K max -K min (ii) a Introducing an equipartition value L, L = (K) max -K min )/J；
Equally dividing the permeability coefficient field length Y into J intervals according to the equipartition value L, and marking any one interval as an interval B j J =1, 2.. J, let the permeability coefficient at the beginning of J intervals be the permeability coefficient of the interval and be noted as the permeability coefficient fill-in value k j ，k j ＝K min +(j-1)×L；
Dividing R x C permeability coefficients K rc Classifying the obtained values into J intervals according to the values of the obtained values, and recording the classified permeability coefficients as classified permeability coefficients
Wherein the subscript is the permeability coefficient of the class in a permeability coefficient field Γ * Is marked as the position of the classified permeability coefficient in the interval;
step 5, forming a gridding filling space in the simulation device
Paving gauze on the partition board (6) to prevent quartz sand from overflowing from the through hole (14) during the test, then taking R-1 network partition boards A (15) and C-1 network partition boards B (16), wherein the R-1 network partition boards A (15) are inserted into the bottom of the sand box (12) along the direction vertical to the partition board (6), the C-1 network partition boards B (16) are inserted into the bottom of the sand box (12) along the direction parallel to the partition board (6), the two partition boards are spliced in a relatively staggered mode through a gap (17), and a cuboid space with the volume of R multiplied by C is formed in the inner cavity of the sand box (12), namely a field gamma equal to the permeability coefficient is formed in the simulation device * Middle R × C permeability coefficient K rc Corresponding R multiplied by C quartz sand filling spaces, and marking any one filling space as a filling space pi rc (7)；
And 6, reproducing the generated permeability coefficient field in the simulation device, and constructing a physical model
Fill value k according to J permeability coefficients j Preparing J kinds of quartz sand with permeability coefficients;
for R × C classified permeability coefficients
According to the index, the quartz sand with the corresponding permeability coefficient is marked, and the quartz sand is filled into the corresponding filling space pi in the simulation device according to the index rc (7) Compacting, wherein the filling height of the material is the height h3 of the network partition plate; to-be-RxC quartz sand filling space pi rc (7) After all the quartz sand is filled, the R-1 network partition boards A (15) and the C-1 network partition boards B (16) are drawn out from the upper part and compacted again, and after compaction, R multiplied by C quartz sand filling spaces pi rc The sand column (10) forms a heterogeneous quartz sand simulation whole body;
during the test, the water inlet tank (11) is used for injecting water into the heterogeneous quartz sand simulation whole in the sand box (12), after the heterogeneous quartz sand simulation whole is completely saturated, one of the three water outlets (8) is opened, and the matched water stop valve (9) is used for adjusting the hydraulic gradient;
the simulation device formed through the steps and the quartz sand simulation whole formed in the simulation device are the two-dimensional heterogeneous water-containing medium physical model.
2. The method for constructing the physical model of the two-dimensional heterogeneous aqueous medium according to claim 1, wherein the sand box (12) has a length L, the water inlet tank (11) has a length L1, the water discharge tank (13) has a length L2, L1=1/10L-1/5L, and L2 is less than or equal to L1.
3. The method for constructing a physical model of a two-dimensional heterogeneous aqueous medium according to claim 1, wherein the diameter of the through holes (14) is 0.5cm to 1cm, and the number of the through holes (14) is more than 40.
4. The method for constructing the physical model of the two-dimensional heterogeneous aqueous medium according to claim 1, wherein the distance between the three water outlets (8) is 8cm, and during simulation test, the hydraulic gradient between the highest water outlet (8) and the middle water outlet (8) is 0.16, and the hydraulic gradient between the highest water outlet (8) and the lowest water outlet (8) is 0.32.
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| CN116609836B (en) * | 2023-07-19 | 2023-09-19 | 北京建工环境修复股份有限公司 | Geophysical simulation testing device and method for groundwater pollution |
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