CN107421868A - The assay method of unsaturated soil moisture diffusance based on the response of Complete heart block flow process - Google Patents
The assay method of unsaturated soil moisture diffusance based on the response of Complete heart block flow process Download PDFInfo
- Publication number
- CN107421868A CN107421868A CN201710592823.1A CN201710592823A CN107421868A CN 107421868 A CN107421868 A CN 107421868A CN 201710592823 A CN201710592823 A CN 201710592823A CN 107421868 A CN107421868 A CN 107421868A
- Authority
- CN
- China
- Prior art keywords
- mrow
- soil
- mfrac
- msub
- horizontal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000002689 soil Substances 0.000 title claims abstract description 119
- 238000000034 method Methods 0.000 title claims abstract description 93
- 230000008569 process Effects 0.000 title claims abstract description 55
- 238000003556 assay Methods 0.000 title claims abstract description 11
- 206010003673 Atrioventricular block complete Diseases 0.000 title claims abstract description 6
- 230000004044 response Effects 0.000 title claims abstract description 6
- 201000002931 third-degree atrioventricular block Diseases 0.000 title claims abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 81
- 238000005213 imbibition Methods 0.000 claims abstract description 19
- 238000009792 diffusion process Methods 0.000 claims abstract description 18
- 238000002474 experimental method Methods 0.000 claims abstract description 16
- 238000012360 testing method Methods 0.000 claims abstract description 16
- 238000004458 analytical method Methods 0.000 claims abstract description 8
- 238000005259 measurement Methods 0.000 claims abstract description 8
- 230000004907 flux Effects 0.000 claims abstract description 6
- 239000011159 matrix material Substances 0.000 claims abstract description 5
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 3
- 238000006073 displacement reaction Methods 0.000 claims description 7
- 230000009466 transformation Effects 0.000 claims description 5
- HPNSNYBUADCFDR-UHFFFAOYSA-N chromafenozide Chemical compound CC1=CC(C)=CC(C(=O)N(NC(=O)C=2C(=C3CCCOC3=CC=2)C)C(C)(C)C)=C1 HPNSNYBUADCFDR-UHFFFAOYSA-N 0.000 claims description 4
- 238000007405 data analysis Methods 0.000 claims description 4
- 238000010586 diagram Methods 0.000 claims description 4
- 238000012279 drainage procedure Methods 0.000 claims description 4
- 230000005484 gravity Effects 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 3
- 238000009736 wetting Methods 0.000 claims description 3
- 238000009825 accumulation Methods 0.000 claims description 2
- 238000005192 partition Methods 0.000 claims description 2
- 230000000149 penetrating effect Effects 0.000 claims 1
- 238000010998 test method Methods 0.000 abstract description 3
- 238000010924 continuous production Methods 0.000 abstract 1
- 238000012544 monitoring process Methods 0.000 abstract 1
- 230000007246 mechanism Effects 0.000 description 9
- 239000011521 glass Substances 0.000 description 7
- 230000008859 change Effects 0.000 description 6
- 210000005056 cell body Anatomy 0.000 description 4
- 238000011161 development Methods 0.000 description 4
- 238000000502 dialysis Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000008595 infiltration Effects 0.000 description 3
- 238000001764 infiltration Methods 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 238000006467 substitution reaction Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000002706 hydrostatic effect Effects 0.000 description 2
- 241000973497 Siphonognathus argyrophanes Species 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 210000000476 body water Anatomy 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002262 irrigation Effects 0.000 description 1
- 238000003973 irrigation Methods 0.000 description 1
- 230000002045 lasting effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000007726 management method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/082—Investigating permeability by forcing a fluid through a sample
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N2015/0023—Investigating dispersion of liquids
- G01N2015/0034—Investigating dispersion of liquids in solids
Landscapes
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a kind of assay method of the unsaturated soil moisture diffusance based on the response of Complete heart block flow process, including horizontal imbibition process and level to penetrate and diffusance experiment is determined in process continuous process；Pass through total amount of infiltrating water and each horizontal level moisture content during imbibition in level monitoring earth pillar；Do not formed before border goes out stream, draw θ~η relation curves and be simultaneously modified based on measured value；Split θ~η curves by certain θ values, D (θ) value is sought with graphic analytic method；After formation border goes out stream, level is converted into by horizontal imbibition process and penetrates process, diverse location soil matrix gesture and right side boundary flux is determined, determines diffusion coefficient.This invention solves the problems, such as to need in existing method of testing test philosophy to unsaturation moisture diffusance D (θ)~θ non-linear relations approximate linearization and measurement error control, and information is clearly directly perceived, and has originality in the field.
Description
Technical field
The present invention relates to soil water movement studying technological domain, more particularly to a kind of unsaturated soil moisture diffusance
Assay method.
Background technology
As the progress of society is with economic fast development, contradiction and problem about water resource are becoming increasingly acute, further
The pressure that the sustainable development of socio-economy faces shortage of water resources is increased, how to keep sustainable development and the water resource of agricultural
Effective rate of utilization turn into urgent problem to be solved.Study soil water movement turns into important in social development with comprehensively utilizing
Problem.Soil water movement is a complicated process, close with many factors such as irrigation method, edaphic condition and external environment
It is related.Soil moisture diffusance is the important parameter of soil water movement equation, and the assay method of existing diffusion of soil can
To be summarized as 2 classes.
First kind method：
Soil water movement equation using soil moisture content θ as variable is：
Wherein, θ is soil moisture content, and x and t are respectively room and time coordinate, and D (θ) is diffusion of soil, and K is waterpower
Conductivity.
After equation (1) is turned to secondary ODE by existing method by the change of secondary partial differential equation, analytic solutions are obtained.
Then tested under the corresponding definite condition (boundary condition and primary condition) of analytic solutions, according to respectively being supervised in test process
Measuring point moisture changes, based on analytic solutions inverting D (θ).
Second class method：
Between flow of water change under diffusion of soil D (θ) and soil unsaturation hydraulic conductivity and unit water-cut variation
Relation can be expressed as：
Wherein, h is soil matrix gesture, and θ is soil moisture content, and K (θ) is soil unsaturation hydraulic conductivity,For unit
Flow of water change under water-cut variation.
Based on this property, determined by determining characteristic curve of soil moistureWith unsaturation hydraulic conductivity K (θ), root
D (θ) is determined according to (2) formula.
It may be noted that for first kind method, because analytic solutions must solve needs, Chang Wei is converted into for partial differential equation
Need to carry out two, the right side of (1) formula respectively linearization process during being divided to, that is, with the D (θ) between two moisture content
Secant replace the tangent line of point position, that is to say, that under the conditions of the D (θ) based on analytic solutions measure is actually a moisture content
Average value, rather than the direct respective value with θ, although when D (θ)~θ relations are close to linear relationship, can't produce serious
Error, however, for most of soil, particularly D (θ)~θ shows the soil of significant non-linear relation, and error is with regard to non-
Chang Xianzhu, it is not have using this non-linear relation of the method approximation D (θ)~θ of piecewise linearity moreover, for the theory of testing
Method solves this test problem at all.
For the second class method, due to the soil characteristic curve of same moisture content (or under matric potential) and non-full can not be realized
With the Simultaneous Determination of hydraulic conductivity.Therefore it is more often the soil moisture curve and unsaturated water determined according to fitting
Power conductivity relation, directly calculates D (θ) in the case of a certain moisture content, and such D (θ) is just surveyed by characteristic curve of soil moisture
The influence of error, unsaturation hydraulic conductivity measurement error and characteristic curve of soil moisture error of fitting is measured, under certain situation
(spy than be in soil clay content more than 30%), error and D (θ) are in the same order of magnitude.
In addition, both approaches also have a common problem, covering completely for unsaturation moisture content section can not be realized
Lid, reason for that are：In the case of soil moisture content is less, water movement is mainly in soil solid particle in soil
It is moved in the presence of molecular force, and as the increase of soil moisture content, the effect of soil capillary force strengthen.Due to active force
Difference, non-linear flowing relation is very big with the difference in change opposite sex of the soil texture in soil.The survey of the moisture content of existing method
It is difficult the whole unsaturation moisture content section of covering to determine scope.
As described above, the system of the measure soil moisture diffusance of complete set is not set up also, can not be to solve
The problems such as agricultural water resources efficiently utilize provides science and supported.
The content of the invention
The problem of being existed based on existing method, the present invention propose a kind of based on the non-of Complete heart block flow process response
The assay method of saturated soil moisture diffusion degree, the straight of D (θ)~θ non-linear relations is realized in method of testing and analytic method
Connect measure.Compared to existing method, advance of the invention is that proposed measuring mechanism can sufficiently react D's (θ)
Physical property, solves traditional method to this great survey of this non-linear process progress linearization process of soil unsaturation flowing
Try mechanism problem.
The inventive method is that a kind of soil that process METHOD FOR CONTINUOUS DETERMINATION is penetrated based on horizontal unsaturation imbibition process and level is non-
The new technology of saturation moisture diffusance, for the height more accurately studied unsaturated soil moisture motion, realize agricultural water resources
Effect utilizes and provides support.
Technical scheme provided by the present invention is specific as follows：
A kind of assay method of the unsaturated soil moisture diffusance based on the response of Complete heart block flow process, passes through water
Flat imbibition process measure and level penetrate process measure, realize the unsaturated soil diffusion for covering whole unsaturation moisture content scope
Degree measure, comprises the following steps：
Step 1, horizontal soil column experimental rig is prepared, the horizontal soil column experimental rig includes the water supply par dress being sequentially communicated
Put, hydroecium, horizontal soil column, ooze out device for measuring flux, water supply par device is used for the acting head for controlling earth pillar, horizontal soil column
By a left side to even partition into some knot earth pillars, interior arrangement soil moisture content and matric potential determination sensor per knot earth pillar, respectively
Sensor is connected with data acquisition unit；The water supply par device is used in the case where control head height is constant, to experiment
Soil sample is supplied water；
Step 2, carry out horizontal imbibition process to unsaturated soil to determine, be implemented as follows：
1. preparing soil sample and filling earth pillar, enough samples are got out, it is desirable to which sample air-dries water content；
2. preparing earth pillar, sample is loaded into earth pillar by certain unit weight, it is then that earth pillar is horizontal positioned, and it is installed on horizontal soil
In column test device；
3. water level settings are carried out to water supply par device according to test head height requirement；Timing simultaneously writes down water supply par dress
Put initial water level reading；
4. pass through certain time, and wetting zone do not reach earth pillar end before, terminate experiment, now stop supply par device
Water supply to earth pillar, what record was entirely tested lasts, total amount of infiltrating water and each point moisture content；
After formation border goes out stream, level is converted into by horizontal imbibition process and penetrates process；
Step 3, process measure is penetrated to unsaturated soil carry out level, is implemented as follows：
Enter in earth pillar after water boundaries form out stream, earth pillar water outlet border head is converted during experiment, when determining different
Carve the displacement of t；
Step 4, θ~η relation curves are drawn according to total amount of infiltrating water and each point moisture content recorded in step 2, from the song
Line can calculate to obtain total amount of infiltrating water, and its value should be suitable with actual measurement amount of infiltrating water, if had big difference, should check whether there is meter
Mistake is calculated, if difference is little, local amendment can be made to θ~η curves, make it as far as possible close to measured value；
Step 5, the θ~η relation curves drawn according to step 4, split θ~η curves by certain θ values, use graphical analysis
Method seeks D (θ) value, and draws D (θ)~θ curves；
Step 6, the level in step 3 penetrates test data corresponding to process, drawsRelation is bent
Line, according to its slope, it is determined that the diffusion coefficient in corresponding unsaturation moisture content section.
In said determination method, horizontal imbibition process is carried out to unsaturated soil and determined, specific data analysis method is as follows：
The occurred level motion in the homogeneous soil of horizontal semo-infinite border with soil moisture of the horizontal imbibition process of unsaturation
In the case of carry out analyzing calculating；The known one-dimensional soil horizontal movement differential equation is：
In formula：θ is that to infiltrate with input to enter when being t constantly the horizontal ranges of water boundaries be soil moisture content at x, D
(θ) is diffusion of soil；
To equation (1), using Boltmann converter techniques, obtain：
Formula (2) reflection D (θx) and θxRelation, θxFor the moisture content at x；Tested by horizontal soil column, at a time t,
Determine the moisture content θ at different distance xx, you can θ~η curves are drawn, based on θ~η relation curves, are determined using diagram methodAfter value, D (θ are determined using formula (1)x)~θxRelation；Wherein, θ is that the horizontal range for entering water boundaries with input is
Soil moisture content at x；In order to solve equation (1), using Boltmann converter techniques, x and t two is contained with a new variable
Individual variables separation substitutes into equation and is allowed to be changed into ODE；If θ (x, t)=f [η (x, t)], and make η (x, t)=xt-1/2。
In said determination method, process measure is penetrated to unsaturated soil carry out level, specific data analysis method is as follows：
Maintain a certain suction head H0After reaching stable, instantaneous intensified negative pressure value is to increase Δ H negative pressure, then measure examination
The out of flow procedure of sample, diffusion coefficient is determined using the solution in multistep processes and the analysis method introduced,
H=-H0, t=0,0≤x≤l (4)
Wherein, K is hydraulic conductivity, and D is diffusance, KpFor the hydraulic conductivity of porous plate；△ H are instantaneous in start time
Transformation value；L is the thickness of sample；lpFor the thickness of porous plate；H is soil matrix gesture；T is the time, and x is horizontal direction coordinate；
Formula (3) is the soil water movement equation for the gravity for not considering sample, and formula (4) (5) (6) is definite condition；At these
Under definite condition, obtain：
In formula, WtAnd W∞Respectively the measure displacement of t and accumulation displacement, l are the thickness of sample,Wherein, Kp, lpThe respectively hydraulic conductivity and thickness of porous plate, Rl=a1tga1；A and a1Respectively anZeroth order
With a class number item,WhenWhen desirable series Section 1, its error only 1%；Wherein i is series,
PnThe constant term after laplace transform is carried out for soil water movement equation, D is average diffusion degree；
When Rl is definite value, then on semilogarithmic paperIt is in linear relation, if straight line and horizontal wire clamp
Angle is β, and its straight slope is：
Tan β=- 0.4343a1 2 (8)
Therefore, according to the drainage procedure of actual measurement right side boundary, according to draftingRelation curve is oblique according to its
Rate, you can try to achieve diffusance D values.
It is specific as follows that the horizontal dialysis process of unsaturated soil of the present invention and level penetrate process measuring machine reason：
1. the horizontal dialysis process measure mechanism of unsaturated soil
Soil moisture in longer (being horizontal semo-infinite border in theory) homogeneous soil, with soil molecule masterpiece
Carry out analyzing calculating in the case of being moved with lower occurred level.Known one-dimensional soil water horizontal movement (ignoring Action of Gravity Field) is micro-
Point equation is：
In formula：θ be with the horizontal range of input (entering water boundaries) be x at soil moisture content.In order to solve equation
Formula (1), using Boltmann converter techniques.Equation is substituted into a new variable (two variables separations containing x and t) to be allowed to be changed into normal
The differential equation.
If
θ (x, t)=f [η (x, t)]
And make η (x, t)=xt-1/2For new variables, such primary condition and boundary condition will become：
θ=θi, η=0 (η → ∞)
θ=θs, η=0
Equation (1) is replaced, due to
Substitution formula (1), is obtained：
Formula (2) shows that after Boltmann conversion is carried out, formula (1) is changed into ODE.D η are multiplied by formula (2) both sides, and
From θiIt is integrated to θx(moisture content at x), is obtained
Finally：
Formula (4) reflection D (θx) and θxRelation, tested by horizontal soil column, at a time t, at measure different distance x
Moisture content θx, you can θ~η curves are drawn, there are θ~η relation curves, thenValue andAvailable Graphical Method
, calculated by formula (4), determine D (θx)~θxRelation.
2. unsaturated soil level is perforated through journey measure mechanism
After going out stream on the right side of experimental provision, level is converted to by horizontal imbibition process measure and penetrates process.
Maintain a certain suction head H0, and reached after stabilization (i.e. soil moisture content is constant), instantaneous intensified negative pressure value is (i.e.
Increase Δ H negative pressure), the out of flow procedure of sample is then determined, utilizes the solution in multistep processes and the analysis method introduced
Determine diffusion coefficient.
H=-H0, t=0,0≤x≤l (6)
Wherein, K is hydraulic conductivity, and D is diffusance, KpFor the hydraulic conductivity of porous plate；△ H are instantaneous in start time
Transformation value；L is the thickness of sample；lpFor the thickness of porous plate.
Formula (5) is the soil water movement equation for the gravity for not considering sample, and formula (6) (7) (8) is definite condition.
According to the definition of moisture capacity：
Then formula (5) is represented by：
I.e.：
In right side boundary：The flow discharged from soil sample is equal to the flow for passing through plate from porous, i.e.,:
In formula：Kp, lp are respectively porous plate infiltration coefficient and thickness；H is the pressure differential by porous plate；L grows for soil sample
Degree.
Laplace conversion is carried out to formula (9)：
Formula (9) is：
Above formula general solution is：
Obtained by formula (12)：
Boundary condition (formula (7) and (8)), is transformed to through laplace：
From formula (14) and (15)：
∴c1=c2=c (16)
Formula (16) is substituted into formula (15), obtained：
Order(17) formula of substitution, obtained after collated：
Formula (18) is substituted into formula (16), obtained：
In formula：ψ (P) is multinomial.
Formula (19) is subjected to inverse transformation, obtained according to residue theorem：
Order：Then formula (20) is：
That is rl=atga (21)
Obtained by formula (17)：
Formula (20) is substituted into formula (22), and P is rewritten as Pn, obtain
From formula (19)：
Obtained by formula (22), (24)：
ψ ' (0)=1；
According to decomposition theorem：
(25) formula of substitution：
The water cross-sectional area for testing body is F, then water QtFor：
In formula：V is soil sample volume.
By formula (28)：
As t=0, Qi=AV+BV △ h；
During t → ∞, Qf=AV；
Therefore when negative pressure increases a certain △ h values, total amount of drainage is：
W∞=Qi-Qf=BV △ h
I.e.：
From formula (29)
∴ B are essentially average moisture capacity (when negative pressure is a certain value).
When negative pressure increases a certain △ h values, the accumulative displacement of t is
WhenWhen desirable series Section 1, its error only 1%.Formula (29) can be written as
Both members are taken the logarithm
From formula (31), right-hand member Section 1 is intercept, that is, is worked asWhen,It is only relevant with Rl.When Rl is fixed
During value, then on semilogarithmic paperIt is in linear relation.If straight line and horizontal line angle are β, its straight slope
For：
Tan β=- 0.4343a1 2 (34)
Therefore, according to the drainage procedure of actual measurement right side boundary, according to draftingRelation curve is oblique according to its
Rate, you can try to achieve diffusance D values.
In the present invention, the glass tube mouth of pipe of water supply par device is deep into the bottom of water supply cell body, such water supply cell body
Hydrostatic pressing is just equal to the liquid level of this glass mouth of pipe, in supply flume body after water body outflow, forms vacuum in cell body, air only from
Enter in glass tube, the glass mouth of pipe is ingress of air point, and water body water level exports not less than glass tube in supply flume body, glass tube
The increase and decrease of water body will not influence hydrostatic pressing in mouth above supply flume body, so as to maintain the constant of flow velocity automatically.
Compared with prior art, the invention has the advantages that：
1. the present invention penetrates process by horizontal imbibition process measure and level and determined, unsaturation moisture content section is realized
The unsaturated soil moisture diffusance D (θ) being completely covered measure；Wherein horizontal imbibition process determines soil moisture content in field
Between specific retention with the moisture diffusion degree of lower curtate, and level penetrates process and determines soil moisture content in field capacity~saturation
The soil moisture diffusance of section between moisture content.
2. test philosophy of the present invention can effectively reflect that unsaturated flow kinematic nonlinearities flow this physical characteristic, and
It is not the linear approximation in existing method, measuring principle has more accurate physical mechanism.
3. the present invention proposes a kind of unsaturation diffusance D's (θ) with complete soil unsaturation mechanism mechanism
Determine mechanism, and the specific implementation of mechanism.In fact, the physical basis of the measuring principle of this method of testing in itself are very multiple
It is miscellaneous, and we in order that it is of the invention be easy to apply, for two processes all on the basis of principle, it is proposed that be relatively easy to reality
Existing assay method：Using horizontal soil column experimental rig, when testing beginning, contained by determining each position soil of horizontal direction
The change of water rate, horizontal imbibition process is measured；When infiltration sharp side reaches right side water outlet border, after forming out stream, change
Water management boundary condition is entered in left side, oozes out flux by the soil matrix gesture and border that determine each position of horizontal direction, right
Level penetrates process and is measured, and when oozing out flux stabilized, soil is fully saturated, and measure terminates.This makes it possible to reality
Existing soil realizes the complete of unsaturation moisture content section from dry ground (moisture content 0) to the measure of the D (θ) saturated aqueous rate
All standing.
4. experimental method of the present invention is simpler, accurately；Using Boltmann converter technique transformation equations, more efficiently；Gram
The deficiency that existing determination techniques are complicated, time-consuming, expense is huge is taken.
5. the experimental method of the present invention, improving soil moisture diffusance D (θ) computational accuracy, solves general measure side
Method is time-consuming, it is laborious, take the defects of fund, information is clearly directly perceived, and has originality in the field.
Brief description of the drawings
Fig. 1 is horizontal soil column test apparatus structure schematic diagram in the present invention；
Fig. 2 is water supply par apparatus structure schematic diagram in the present invention；
Fig. 3 is θ~η relation curves of the embodiment of the present invention；
Fig. 4 is the relative outflow of right side boundary that the embodiment of the present invention is drawn on semilogarithmic paperClose
System's figure.
In figure：1- water supply par devices；The glass tube of 1a- controlling water levels；1b- water supply cell bodies；1c- delivery ports；2- hydroeciums；
3- steam vents；Filter before 4-；5- earth pillars；6- soil moisture contents and matric potential determination sensor；7- data acquisition units；Mistake after 8-
Filter plate；9- oozes out device for measuring flux.
Embodiment
Understand for the ease of those of ordinary skill in the art and implement the present invention, below in conjunction with the accompanying drawings and embodiment is to this hair
It is bright to be described in further detail, it will be appreciated that implementation example described herein is merely to illustrate and explain the present invention, not
For limiting the present invention.It should be pointed out that to those skilled in the art, before present inventive concept is not departed from
Put, various modifications and improvements can be made.These belong to protection scope of the present invention.
＜ embodiments ＞
This experiment elaborates the solution of the present invention by two kinds of implementation methods, and specific implementation step is as follows：
1. preparing soil sample and filling earth pillar, enough samples (air-dried water content) are got out.Earth pillar is loaded by certain unit weight,
Screw rod is screwed then horizontal positioned.
2. instantaneously to hydroecium water-filling and position water supply par device.
3. timing simultaneously writes down supply tank initial water level reading.
4. by reasonable time (wetting zone do not reach at earth pillar end before) after, you can terminate experiment, now stop supplying water,
Firm screw rod is unclamped, soil test moisture content is taken out by section, writes down lasting of entirely testing and total Water, cleans vessel, experiment
Terminate.
θ~η relation curves are drawn, as shown in figure 3, can calculate to obtain total amount of infiltrating water from the curve, its value should be with measured value W
Quite, if had big difference, calculating mistake should be checked whether there is, if difference is little, part can be made to θ~η curves
Amendment, make it as far as possible close to measured value.
For horizontal dialysis process：
After there are θ~η relation curves, split θ~η curves by certain θ values, see Fig. 3.If earth pillar initial aqueous rate θiFor
3%, if seeking θxD (θ) when=8%, is only requiredAndTwo (ηiAnd ηxFor θiFor 3%, and θx=8%
Corresponding η values), then D (θ) can be tried to achieve.In θxθ~η slope of a curves are asked for at=8%Measured again with volumetric method
Abdc area (Fig. 3), you can try to achieveIt is worth (θi=3%, θx=8%), willValue andJust θ is calculated to obtain
D (θ) value when=8%, due toIt is worth for negative, therefore D (θ) value calculated is positive number.In the same way, other can be tried to achieve to contain
The D (θ) of water rate value.
Process is penetrated for level：
Right-hand member Section 1 is intercept, that is, is worked asWhen,It is only relevant with Rl.It is when Rl is definite value, then right half
On number paperIt is in linear relation, see Fig. 4.If straight line and horizontal line angle are β, its straight slope is：
Tan β=- 0.4343a1 2
According to the drainage procedure according to actual measurement right side boundary, according to draftingRelation curve is oblique according to its
Rate, you can try to achieve diffusance D values.
The invention discloses a kind of assay method of soil moisture diffusance, including horizontal imbibition process measure and level to wear
Through journey measure diffusance experiment.It is first according to horizontal soil column experimental rig figure and prepares experiment, record experiment lasts, total Infiltration water
Amount and each point moisture content etc.；Then θ~η relation curves are drawn and make local amendment to θ~η curves, make it as far as possible close to real
Measured value；Split θ~η curves by certain θ values, seek D (θ) value with graphic analytic method, and draw D (θ)~θ curves；Finally utilize
Grittiness funnel determines the device of water characteristic curve, and out of flow procedure is observed during experiment, determines diffusion coefficient.
The present invention carried out in specified level soil-column test device, water supply par device to controlled level earth pillar effect
Head,
It should be appreciated that the part that this specification does not elaborate belongs to prior art.
It should be appreciated that the above-mentioned description for preferred embodiment is more detailed, therefore can not be considered to this
The limitation of invention patent protection scope, one of ordinary skill in the art are not departing from power of the present invention under the enlightenment of the present invention
Profit is required under protected ambit, can also be made replacement or deformation, be each fallen within protection scope of the present invention, this hair
It is bright scope is claimed to be determined by the appended claims.
Claims (3)
1. a kind of assay method of the unsaturated soil moisture diffusance based on the response of Complete heart block flow process, its feature exist
In penetrating process by horizontal imbibition process measure and level and determine, realize and cover the non-full of whole unsaturation moisture content scope
Determine, comprise the following steps with diffusion of soil：
Step 1, prepare horizontal soil column experimental rig, the horizontal soil column experimental rig include be sequentially communicated water supply par device,
Hydroecium, horizontal soil column, ooze out device for measuring flux, water supply par device is used for the acting head for controlling earth pillar, horizontal soil column by
A left side is to even partition into some knot earth pillars, interior arrangement soil moisture content and matric potential determination sensor, each biography per knot earth pillar
Sensor is connected with data acquisition unit；
Step 2, carry out horizontal imbibition process to unsaturated soil to determine, be implemented as follows：
1. preparing soil sample and filling earth pillar, enough samples are got out, it is desirable to which sample air-dries water content；
2. preparing earth pillar, sample is loaded into earth pillar by certain unit weight, it is then that earth pillar is horizontal positioned, and it is installed on horizontal soil column examination
In experiment device；
3. water level settings are carried out to water supply par device according to test head height requirement；Timing and at the beginning of writing down water supply par device
Beginning water level reading；
4. pass through certain time, and wetting zone do not reach earth pillar end before, terminate experiment, now stop for par device to soil
The water supply of post, what record was entirely tested lasts, total amount of infiltrating water and each point moisture content；
After formation border goes out stream, level is converted into by horizontal imbibition process and penetrates process；
Step 3, process measure is penetrated to unsaturated soil carry out level, is implemented as follows：
Enter in earth pillar after water boundaries form out stream, convert earth pillar water outlet border head during experiment, measure at different moments t when
The displacement at quarter；
Step 4, θ~η relation curves are drawn according to total amount of infiltrating water and each point moisture content recorded in step 2, can from the curve
To calculate to obtain total amount of infiltrating water, its value should be suitable with actual measurement amount of infiltrating water, if had big difference, it is wrong should to check whether there is calculating
By mistake, if difference is little, local amendment can be made to θ~η curves, make it as far as possible close to measured value；
Step 5, the θ~η relation curves drawn according to step 4, split θ~η curves by certain θ values, D is sought with graphic analytic method
(θ) value, and draw D (θ)~θ curves；
Step 6, the level in step 3 penetrates test data corresponding to process, drawsRelation curve,
According to its slope, it is determined that the diffusion coefficient in corresponding unsaturation moisture content section.
2. assay method according to claim 1, it is characterised in that：Horizontal imbibition process is carried out to unsaturated soil to survey
Fixed, specific data analysis method is as follows：
The horizontal imbibition process of unsaturation is with the soil moisture situation that occurred level moves in the homogeneous soil of horizontal semo-infinite border
It is lower to carry out analyzing calculating；The known one-dimensional soil horizontal movement differential equation is：
<mrow>
<mfrac>
<mrow>
<mo>&part;</mo>
<mi>&theta;</mi>
</mrow>
<mrow>
<mo>&part;</mo>
<mi>t</mi>
</mrow>
</mfrac>
<mo>=</mo>
<mfrac>
<mrow>
<mo>&part;</mo>
<mo>&lsqb;</mo>
<mi>D</mi>
<mrow>
<mo>(</mo>
<mi>&theta;</mi>
<mo>)</mo>
</mrow>
<mfrac>
<mrow>
<mo>&part;</mo>
<mi>&theta;</mi>
</mrow>
<mrow>
<mo>&part;</mo>
<mi>x</mi>
</mrow>
</mfrac>
<mo>&rsqb;</mo>
</mrow>
<mrow>
<mo>&part;</mo>
<mi>x</mi>
</mrow>
</mfrac>
<mo>-</mo>
<mo>-</mo>
<mo>-</mo>
<mrow>
<mo>(</mo>
<mn>1</mn>
<mo>)</mo>
</mrow>
</mrow>
In formula：θ is that to infiltrate with input to enter when being t constantly the horizontal ranges of water boundaries be soil moisture content at x, and D (θ) is
Diffusion of soil；
To equation (1), using Boltmann converter techniques, obtain：
<mrow>
<mi>D</mi>
<mrow>
<mo>(</mo>
<msub>
<mi>&theta;</mi>
<mi>x</mi>
</msub>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<msub>
<mrow>
<mo>(</mo>
<mfrac>
<mrow>
<mi>d</mi>
<mi>&theta;</mi>
</mrow>
<mrow>
<mi>d</mi>
<mi>&eta;</mi>
</mrow>
</mfrac>
<mo>)</mo>
</mrow>
<msub>
<mi>&theta;</mi>
<mi>i</mi>
</msub>
</msub>
</mfrac>
<mrow>
<mo>(</mo>
<mo>-</mo>
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
<mo>)</mo>
</mrow>
<msubsup>
<mo>&Integral;</mo>
<msub>
<mi>&theta;</mi>
<mi>i</mi>
</msub>
<msub>
<mi>&theta;</mi>
<mi>x</mi>
</msub>
</msubsup>
<mi>&eta;</mi>
<mi>d</mi>
<mi>&theta;</mi>
<mo>-</mo>
<mo>-</mo>
<mo>-</mo>
<mrow>
<mo>(</mo>
<mn>2</mn>
<mo>)</mo>
</mrow>
</mrow>
Formula (2) reflection D (θx) and θxRelation, θxFor the moisture content at x；Tested, at a time t, determined by horizontal soil column
Moisture content θ at different distance xx, you can θ~η curves are drawn, based on θ~η relation curves, are determined using diagram methodValue
Afterwards, D (θ are determined using formula (1)x)~θxRelation；Wherein, θ is to enter the horizontal ranges of water boundaries with input for the soil at x
Earth moisture content；In order to solve equation (1), using Boltmann converter techniques, with a new variable i.e. containing two separation of x and t
Variable substitutes into equation and is allowed to be changed into ODE；If θ (x, t)=f [η (x, t)], and make η (x, t)=xt-1/2。
3. assay method according to claim 1, it is characterised in that：Process survey is penetrated to unsaturated soil carry out level
Fixed, specific data analysis method is as follows：
Maintain a certain suction head H0After reaching stable, instantaneous intensified negative pressure value is to increase Δ H negative pressure, then determines sample
Out of flow procedure, diffusion coefficient is determined using the solution in multistep processes and the analysis method introduced,
<mrow>
<mfrac>
<mrow>
<mo>&part;</mo>
<mi>h</mi>
</mrow>
<mrow>
<mo>&part;</mo>
<mi>t</mi>
</mrow>
</mfrac>
<mo>=</mo>
<mi>D</mi>
<mrow>
<mo>(</mo>
<mi>&theta;</mi>
<mo>)</mo>
</mrow>
<mfrac>
<mrow>
<msup>
<mo>&part;</mo>
<mn>2</mn>
</msup>
<mi>h</mi>
</mrow>
<mrow>
<mo>&part;</mo>
<msup>
<mi>x</mi>
<mn>2</mn>
</msup>
</mrow>
</mfrac>
<mo>-</mo>
<mo>-</mo>
<mo>-</mo>
<mrow>
<mo>(</mo>
<mn>3</mn>
<mo>)</mo>
</mrow>
</mrow>
H=-H0, t=0,0≤x≤l (4)
<mrow>
<mfrac>
<mrow>
<mo>&part;</mo>
<mi>h</mi>
</mrow>
<mrow>
<mo>&part;</mo>
<mi>x</mi>
</mrow>
</mfrac>
<mo>=</mo>
<mn>0</mn>
<mo>,</mo>
<mi>x</mi>
<mo>=</mo>
<mn>0</mn>
<mo>,</mo>
<mi>t</mi>
<mo>&GreaterEqual;</mo>
<mn>0</mn>
<mo>-</mo>
<mo>-</mo>
<mo>-</mo>
<mrow>
<mo>(</mo>
<mn>5</mn>
<mo>)</mo>
</mrow>
</mrow>
Wherein, K is hydraulic conductivity, and D is diffusance, KpFor the hydraulic conductivity of porous plate；△ H are the instantaneous transformation in start time
Value；L is the thickness of sample；lpFor the thickness of porous plate；H is soil matrix gesture；T is the time, and x is horizontal direction coordinate；
Formula (3) is the soil water movement equation for the gravity for not considering sample, and formula (4) (5) (6) is definite condition；In these fixed solutions
Under the conditions of, obtain：
<mrow>
<mi>lg</mi>
<mfrac>
<mrow>
<msub>
<mi>W</mi>
<mi>&infin;</mi>
</msub>
<mo>-</mo>
<msub>
<mi>W</mi>
<mi>t</mi>
</msub>
</mrow>
<msub>
<mi>W</mi>
<mi>&infin;</mi>
</msub>
</mfrac>
<mo>=</mo>
<mi>lg</mi>
<mfrac>
<mrow>
<mn>2</mn>
<msup>
<mi>R</mi>
<mn>2</mn>
</msup>
<msup>
<mi>l</mi>
<mn>2</mn>
</msup>
</mrow>
<mrow>
<msup>
<msub>
<mi>a</mi>
<mn>1</mn>
</msub>
<mn>2</mn>
</msup>
<mo>&lsqb;</mo>
<mi>R</mi>
<mi>l</mi>
<mrow>
<mo>(</mo>
<mi>R</mi>
<mi>l</mi>
<mo>+</mo>
<mn>1</mn>
<mo>)</mo>
</mrow>
<mo>+</mo>
<msup>
<msub>
<mi>a</mi>
<mn>1</mn>
</msub>
<mn>2</mn>
</msup>
<mo>&rsqb;</mo>
</mrow>
</mfrac>
<mo>-</mo>
<mn>0.4343</mn>
<msup>
<msub>
<mi>a</mi>
<mn>1</mn>
</msub>
<mn>2</mn>
</msup>
<mfrac>
<mrow>
<mi>D</mi>
<mi>t</mi>
</mrow>
<msup>
<mi>l</mi>
<mn>2</mn>
</msup>
</mfrac>
<mo>-</mo>
<mo>-</mo>
<mo>-</mo>
<mrow>
<mo>(</mo>
<mn>7</mn>
<mo>)</mo>
</mrow>
</mrow>
In formula, WtAnd W∞Respectively the measure displacement of t and accumulation displacement, l are the thickness of sample,Its
In, Kp, lpThe respectively hydraulic conductivity and thickness of porous plate, Rl=a1tga1；A and a1Respectively anZero and first order level it is several,WhenWhen desirable series Section 1, its error only 1%；Wherein i is series, PnFor soil moisture
The equation of motion carries out the constant term after laplace transform, and D is average diffusion degree；When Rl is definite value, then on semilogarithmic paperIn linear relation, if straight line and horizontal line angle are β, its straight slope is：
Tan β=- 0.4343a1 2 (8)
Therefore, according to the drainage procedure of actual measurement right side boundary, according to draftingRelation curve, according to its slope, i.e.,
Diffusance D values can be tried to achieve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710592823.1A CN107421868B (en) | 2017-07-19 | 2017-07-19 | Method for measuring unsaturated soil moisture diffusivity based on complete nonlinear flow process response |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710592823.1A CN107421868B (en) | 2017-07-19 | 2017-07-19 | Method for measuring unsaturated soil moisture diffusivity based on complete nonlinear flow process response |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107421868A true CN107421868A (en) | 2017-12-01 |
| CN107421868B CN107421868B (en) | 2020-05-12 |
Family
ID=60430686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710592823.1A Expired - Fee Related CN107421868B (en) | 2017-07-19 | 2017-07-19 | Method for measuring unsaturated soil moisture diffusivity based on complete nonlinear flow process response |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107421868B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108680470A (en) * | 2018-07-17 | 2018-10-19 | 武汉大学 | Microspray irrigation Soil Under Conditions water infiltrates distribution test method |
| CN108918333A (en) * | 2018-07-18 | 2018-11-30 | 武汉大学 | A method of measurement characteristic curve of soil moisture and unsaturation hydraulic conductivity |
| CN111208042A (en) * | 2020-02-07 | 2020-05-29 | 中国科学院武汉岩土力学研究所 | Device and method for inverting hydraulic parameters of unsaturated waste soil |
| CN112146845A (en) * | 2020-09-27 | 2020-12-29 | 武汉大学 | Method for testing instantaneous and complete elastic water release coefficients of underground water |
| CN112161897A (en) * | 2020-09-27 | 2021-01-01 | 武汉大学 | Negative pressure boundary control method for large-scale soil water movement experiment system |
| CN113588916A (en) * | 2021-07-09 | 2021-11-02 | 河海大学 | Method for predicting water accumulation adsorption in expansive soil |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63309837A (en) * | 1987-06-12 | 1988-12-16 | Shimizu Constr Co Ltd | Constant-water level infiltration testing device |
| CN101788450A (en) * | 2010-02-01 | 2010-07-28 | 中国海洋大学 | Measuring method of osmosis of non-homogeneous water-bearing medium |
| CN104359801A (en) * | 2014-11-20 | 2015-02-18 | 中国地质大学（武汉） | Multi-stage aeration zone soil moisture diffusion tester based on one-dimensional horizontal flow |
| CN105259088A (en) * | 2015-11-03 | 2016-01-20 | 三峡大学 | Method and device for quickly determining permeability functions of unsaturated soil |
| CN105588796A (en) * | 2015-12-17 | 2016-05-18 | 扬州大学 | Device for accurately and rapidly determining permeability coefficient of soil |
| CN106769787A (en) * | 2017-02-17 | 2017-05-31 | 宿州学院 | A kind of multimedium infiltration experiment device and its method of testing |
-
2017
- 2017-07-19 CN CN201710592823.1A patent/CN107421868B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63309837A (en) * | 1987-06-12 | 1988-12-16 | Shimizu Constr Co Ltd | Constant-water level infiltration testing device |
| CN101788450A (en) * | 2010-02-01 | 2010-07-28 | 中国海洋大学 | Measuring method of osmosis of non-homogeneous water-bearing medium |
| CN104359801A (en) * | 2014-11-20 | 2015-02-18 | 中国地质大学（武汉） | Multi-stage aeration zone soil moisture diffusion tester based on one-dimensional horizontal flow |
| CN105259088A (en) * | 2015-11-03 | 2016-01-20 | 三峡大学 | Method and device for quickly determining permeability functions of unsaturated soil |
| CN105588796A (en) * | 2015-12-17 | 2016-05-18 | 扬州大学 | Device for accurately and rapidly determining permeability coefficient of soil |
| CN106769787A (en) * | 2017-02-17 | 2017-05-31 | 宿州学院 | A kind of multimedium infiltration experiment device and its method of testing |
Non-Patent Citations (1)
| Title |
|---|
| 张蔚榛等: "土壤水分运动参数测定方法", 《水文地质工程地质》 * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108680470A (en) * | 2018-07-17 | 2018-10-19 | 武汉大学 | Microspray irrigation Soil Under Conditions water infiltrates distribution test method |
| CN108918333A (en) * | 2018-07-18 | 2018-11-30 | 武汉大学 | A method of measurement characteristic curve of soil moisture and unsaturation hydraulic conductivity |
| CN111208042A (en) * | 2020-02-07 | 2020-05-29 | 中国科学院武汉岩土力学研究所 | Device and method for inverting hydraulic parameters of unsaturated waste soil |
| CN111208042B (en) * | 2020-02-07 | 2021-06-29 | 中国科学院武汉岩土力学研究所 | Device and method for inverting hydraulic parameters of unsaturated waste soil |
| CN112146845A (en) * | 2020-09-27 | 2020-12-29 | 武汉大学 | Method for testing instantaneous and complete elastic water release coefficients of underground water |
| CN112161897A (en) * | 2020-09-27 | 2021-01-01 | 武汉大学 | Negative pressure boundary control method for large-scale soil water movement experiment system |
| CN112161897B (en) * | 2020-09-27 | 2021-10-22 | 武汉大学 | Negative pressure boundary control method for large-scale soil water movement experiment system |
| CN112146845B (en) * | 2020-09-27 | 2021-11-02 | 武汉大学 | Method for testing instantaneous and complete elastic water release coefficients of underground water |
| CN113588916A (en) * | 2021-07-09 | 2021-11-02 | 河海大学 | Method for predicting water accumulation adsorption in expansive soil |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107421868B (en) | 2020-05-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107421868A (en) | The assay method of unsaturated soil moisture diffusance based on the response of Complete heart block flow process | |
| CN102980842B (en) | System and method for testing anisotropy permeability coefficient of layered coarse-grained soil body | |
| CN103529237B (en) | The measuring method of a kind of fo Sediment Group Settling speed and measurement apparatus | |
| CN106814018A (en) | A kind of tight rock gas phase relative permeability measurement apparatus and method | |
| CN107121369A (en) | A kind of full-automatic Darcy's law experimental system | |
| CN108318396A (en) | The test method of Seepage Field of Tailings Dam analog simulation pilot system | |
| CN102636630A (en) | Large unsaturated seepage physical simulator for soil in aerated zone | |
| CN106644890A (en) | Device for measuring soil sample permeability coefficient in indoor soil engineering test | |
| Hentschel et al. | Simulation of stand transpiration based on a xylem water flow model for individual trees | |
| Zhao et al. | Characterizing uncertainty in process-based hydraulic modeling, exemplified in a semiarid Inner Mongolia steppe | |
| CN105259088A (en) | Method and device for quickly determining permeability functions of unsaturated soil | |
| CN107066687A (en) | A kind of soil rainfall infiltration measurement system and method for considering air drag effect | |
| Ren et al. | Heat tracer test in a riparian zone: laboratory experiments and numerical modelling | |
| CN107328685A (en) | Go out the method that stream method determines unsaturated soil Hydrodynamic Parameters with pressure plare/pressure membrane | |
| CN102680374B (en) | Test device for determining non-saturated soil osmotic parameter | |
| CN207073409U (en) | A kind of gas reservoir inhomogeneous plane water enchroachment (invasion) analogue experiment installation | |
| CN110208497A (en) | A kind of portable soil specific yield tester and test method | |
| CN204944999U (en) | A kind of simple and easy humidification soil sample pore water pressure real-time test device | |
| Watson | Experimental and numerical study of column drainage | |
| CN206431025U (en) | It is used for the device for measuring soil sample infiltration coefficient in a kind of laboratory soil test | |
| CN110108854A (en) | A kind of experimental provision for simulating the different each rock stratum flow of permeability, flow velocity relation | |
| CN208537135U (en) | One kind is for the husky mutually feedback experimental monitoring system of complex condition river and lake water | |
| Tang et al. | Experimental evaluation of theoretical solutions for subsurface drainage and irrigation | |
| CN208366759U (en) | A kind of capillary water experimental rig based on weighing principle | |
| CN104215540A (en) | Tipping bucket type crude oil water content online monitoring device and online monitoring method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200512 |