CN102937545A - Method for maintaining constant degree of saturation of test soil body - Google Patents
Method for maintaining constant degree of saturation of test soil body Download PDFInfo
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- CN102937545A CN102937545A CN2012104477824A CN201210447782A CN102937545A CN 102937545 A CN102937545 A CN 102937545A CN 2012104477824 A CN2012104477824 A CN 2012104477824A CN 201210447782 A CN201210447782 A CN 201210447782A CN 102937545 A CN102937545 A CN 102937545A
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Abstract
The invention provides a method for maintaining constant degree of saturation of a test soil body and aims to solve the problems that in prior art, the maintenance of the degree of saturation of the test soil body is random and the accurate degree of the test is low. The method includes placing the test soil body in enclosed space; testing the initial temperature and humidity of the air above the soil body, and calculating to obtain an initial air moisture content V1; testing to obtain the relative humidity of current air when the temperature rises to a certain degree, inquiring the dew point temperature which corresponds to the air humidity, and calculating to obtain a current air moisture content V2; calculating a differential value delta V of the current moisture content V2 and an initial moisture content V3 to serve as evaporation amount of moisture in the soil body; and supplementing delta V of moisture into the soil body so as to maintain the constant degree of saturation of the soil body. By means of the method, moisture is accurately supplemented to the soil body, the constant degree of saturation of the soil body can be simply and effectively maintained, and thereby the test result of the experiment is objective, real and reliable.
Description
Technical field
The present invention relates to the test method of a kind of unsaturated soil in civil engineering work soil test field, particularly relate to a kind of constant test method of unsaturated soil saturation degree that keeps.
Background technology
The natural soil body is a kind of three-phase material system of complexity, and wherein soil particle forms the solid soil skeleton, and soil skeleton has been full of liquids and gases between the space, and the space between skeleton all is that liquid is full of, and then forms saturated soil; If the hole of inside soil body part is full of by liquid, then is unsaturated soil.Unsaturated soil is a kind of non-homogeneous porous medium material that is comprised of soil particle and not miscible fluid (such as water---gas, water---oil, water---pollutant etc.), and it extensively is distributed in soil-slope, earth and rockfill dam, Roadbed Soil, refuse landfill and arid---among the semiarid zone.Along with national economy improves constantly transport need, highway, railway construction expanding day, the unsaturated soils such as fine grained soil (slity soil and clayey soil), swelled ground, loess and collapsible soil also increase gradually as roadbed material.In the last few years, along with the fast development of China's economy and the aggravation of human society transformation activity, more and more engineering problems relevant with unsaturated soil had to be solved.
Build is in subgrade engineering, hydraulic engineering and the municipal works etc. in unsaturated soil area, owing to be subject to such as factor affecting such as weathers, shallow-layer unsaturated soil engineering properties changes, and shows as to construct water in the engineering, heat distribution variation.This variation has significant impact to engineering stability, often causes subgrade engineering the diseases such as depression, vertical swollen, ditch fall to occur, and the diseases such as frost heave, bank slump, cracking of building body appear in hydraulic engineering, and the diseases such as frost heave, depression, check crack appear in municipal works.The disease reason is that water cut increases the generation saturated yielding in the soil, strength decreased, and freeze thawing changes native own vol, and male and female face Shang Shui, hot difference cause distortion difference etc., and affecting shallow-layer unsaturated soil engineering stability leading indicator is water cut and temperature.
In order accurately to grasp the impact of the engineering stabilities such as unsaturated soil roadbed engineering with certain soil body saturation degree, hydraulic engineering, people need to carry out take this unsaturated soil as experimental subjects the test of the hydraulic parameters such as soil solidifying, viscoelasticity.Carrying out in the middle of every process of the test of the soil body, because the variation of environment temperature can cause the loss of moisture in the soil body, thereby causing soil body saturation degree to change, affecting the accuracy of test findings.Therefore, maintenance soil body saturation degree is constant in experimentation just seems extremely important.
In order to keep soil body saturation degree constant, the general employing directly added water to keep the way of soil body saturation degree in the prior art in the test soil body.But this way has larger randomness, and soil body saturation degree is stable not, thereby is unfavorable for obtaining accurately experimental result.
Summary of the invention
The object of the present invention is to provide a kind of constant method of unsaturated soil saturation degree that keeps, to overcome the randomness that keeps soil body saturation degree in the prior art, improve the order of accuarcy of test.
The inventor finds by a large amount of experiments:
1, the physical process of soil body moisture evaporation
The condition that the evaporation of soil body moisture continues to carry out is: often have heat to arrive native face, provide the moisture vaporization required heat of vaporization; Soil face vapour pressure is higher than the atmospheric water vapour pressure; The soil face can continue to obtain moisture in the soil.According to the motion conditions of various form moisture, soil body moisture evaporation process is divided three phases:
1. the kapillary operation phase, when the soil body was moistening, water was full of the inside soil body hole, and moisture is by capillarity, and constantly rapidly to the earth's surface operation, moisture is in earth's surface vaporization, diffusion, and the evaporation of soil body moisture is strong.
2. the film operation phase, reduce when the evaporation water consumption makes soil body water cut, during less than capillary water fracture water cut, capillary water disconnects, and capillary conductivity stops, and soil body moisture is moved to the thin place of moisture film by the place that moisture film is thick then with the pellicular water form.Because this motion is slow, the moisture evaporation obviously weakens.At this moment, the evaporation not only carry out on the earth's surface, inside soil body moisture also can be vaporized, and through soil body hole to atmospheric diffusion.
3. spread the operation phase, when the reduction of soil body water cut, during near wilting coefficient, soil body moisture is stopped substantially by the film movement of bottom to native face, only has vaporous water to spread in the soil body of earth's surface, and rate of evaporation is very little.
2, the influence factor of soil body moisture evaporation
Except the same factor that affects evaporation from water surface, soil body water cut, bury of groundwater, soil structures, soil body color and luster, soil body surface feature etc. are arranged still.
1. when soil body water cut when saturated because irregular soil body particle has consisted of larger total evaporation surface, the rapid steamer meeting of the free-water level that rapid steamer can be more identical than horizontal area is many.Water cut plays a decisive role to evaporation in 3～5 cm range of soil body top layer, and down impact is less.
If 2. bury of groundwater is little, phreatic table often remains in the capillarity scope, and then soil body water cut can be replenished enduringly, and evaporation evenly; Otherwise, if bury of groundwater is large, the vary within wide limits that reduces of rate of evaporation then.
3. the soil body of crumb structure, evaporation capacity is little; The soil body of non-crumb structure, evaporation capacity is large.
4. soil body color change soil body surface reflectivity evaporates thereby affect, and soil body color is darker, and evaporation capacity more greatly.The evaporation capacity of the brown soil body is larger 19% than white, and the evaporation capacity of the black soil body is than large 32% of white.
5. the turbulent fluctuation effect of soil body surface feature affects wind, the evaporation capacity of rough earth is larger than level and smooth ground; Landform eminence wind speed is large, and the highland evaporation capacity is larger than the basin; The earth's surface slope aspect is different, affects radiation-absorbing, and evaporation capacity is also different.
As seen, as shown in Figure 1, along with the rising of ambient temperature, the moisture on soil body top constantly enters in the middle of the air with the water vapor form under evaporation; Because soil body top moisture reduces, bottom moisture to the motion of soil body top, causes underground water table constantly to descend under capillary action.As shown in Figure 2, because in the process that temperature raises, it is more and more to enter airborne moisture, the humidity of air strengthens thereupon, and the water loss in the soil body is serious, directly causes the saturation degree of the soil body to descend.Therefore, can consider to keep the invariable of soil body saturation degree by the humidity of adjusting air.
Accordingly, method of the present invention may further comprise the steps: will test the soil body and place a confined space; Test out initial temperature and the humidity of the air on soil body top, calculate initial air moisture content V1; When temperature rises to a certain degree, test the relative humidity that obtains current air, inquiry calculates current air moisture content V2 with dewpoint temperature corresponding to air humidity; Calculate the difference △ V of current water cut V2 and initial water content V3, be the evaporation capacity of moisture in the soil body; The moisture of the △ V water yield is filled into the soil body, constant with the saturation degree that keeps the soil body.
According to method of the present invention, further comprising the steps of: as to form in advance the simulate formation water layer in the confined space bottom.
According to method of the present invention, preferably the mode by artificial spray fills into the soil body with the moisture of the △ V water yield.
According to method of the present invention, preferably moisture is in kapillary and carries out moisturizing during the operation phase in the soil body, thereby so that the water that fills into can dissolve in the soil body by Quick uniform.
Adopt method of the present invention by accurately keeping the skin wet to the soil body, can simply, effectively keep soil body saturation degree constant, thereby so that the test result of experiment be more objective, true, reliable.
Description of drawings
Fig. 1 is soil body water translocation synoptic diagram under the high temperature;
Fig. 2 is according to soil body water translocation synoptic diagram after the method for the invention moisturizing.
Embodiment
Details are as follows to the implementation of the method for the invention below in conjunction with accompanying drawing:
⒈ arranges the simulate formation water layer in the bottom, space of a cuboid;
⒉ places the test soil body on water table top, form the soil body;
The airtight described cuboid of ⒊ space;
⒋ tests out initial temperature and the humidity of the air on confined space top, calculates the air moisture content V1 of soil body top;
After the ⒌ temperature was elevated to a certain degree, test obtained humidity, temperature and the dewpoint temperature of current air, calculated the water cut V2 of current air;
⒍ calculates the difference △ V between V1 and the V2, is the evaporation capacity of moisture in the soil body;
The moisture of ⒎ in the soil body also was in during the kapillary operation phase, and with mode even the spray soil body surface of the water yield by manually spraying of △ V, thereby the saturation degree of the maintenance soil body is constant.
The present invention can summarize with other the concrete form without prejudice to spirit of the present invention or principal character.Therefore, no matter from which point, above-mentioned embodiment of the present invention all can only be thought can not limit the present invention to explanation of the present invention.Claims have been pointed out scope of the present invention, and scope of the present invention is not pointed out in above-mentioned explanation.Therefore, in the implication suitable with claims of the present invention and any change in the scope, all should think to be included in the scope of claims.
Claims (4)
1. constant method of saturation degree that keeps testing the soil body is characterized in that may further comprise the steps:
(1) will test the soil body and place a confined space, form the soil body;
(2) test out initial temperature and the humidity of the air on described soil body top, calculate initial air moisture content V1;
(3) rise to a certain degree when temperature, test out current air humidity, temperature and dewpoint temperature, calculate current air moisture content V2;
(4) calculate the difference △ V of current water cut V2 and initial water content V1, be the evaporation capacity of moisture in the soil body;
(5) moisture with the △ V water yield fills into the soil body, keeps saturation degree constant of the soil body.
2. method according to claim 1 characterized by further comprising following steps: in step (1) before, form the simulate formation water layer in described confined space bottom.
3. method according to claim 2 is characterized in that: in the step (5), the mode by artificial spray fills into the described soil body with the moisture of the △ V water yield.
4. method according to claim 3, it is characterized in that: the moisture in the described soil body is in kapillary and manually sprays moisturizing during the operation phase.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106290801A (en) * | 2016-10-27 | 2017-01-04 | 中南大学 | The Apparatus and method for that soil body saturation controls |
| CN110736761A (en) * | 2019-09-28 | 2020-01-31 | 同济大学 | Visual test device and method for influence of temperature changes on subway tunnel |
| CN114167032A (en) * | 2021-11-29 | 2022-03-11 | 内蒙古科技大学 | Method and device for simulating influence of mining subsidence on soil water and salt migration |
Citations (5)
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| US20100212409A1 (en) * | 2009-02-25 | 2010-08-26 | Ramanathan Sri Ranjan | Plant-Controlled Atmometer for Measuring Crop Evapotranspiration |
| CN101957360A (en) * | 2010-09-10 | 2011-01-26 | 北京大学 | Method and system for measuring surface evapotranspiration quantity |
| CN202095371U (en) * | 2011-06-03 | 2012-01-04 | 李崇平 | Automatic spray system |
| CN102353602A (en) * | 2011-06-15 | 2012-02-15 | 中国水利水电科学研究院 | Compensating automatic measurement system and method of soil surface evaporation capacity |
| CN102696433A (en) * | 2012-07-02 | 2012-10-03 | 昆山卉友生态科技有限公司 | Automatic-irrigation heat-insulating cultivation box for plant cultivation |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100212409A1 (en) * | 2009-02-25 | 2010-08-26 | Ramanathan Sri Ranjan | Plant-Controlled Atmometer for Measuring Crop Evapotranspiration |
| CN101957360A (en) * | 2010-09-10 | 2011-01-26 | 北京大学 | Method and system for measuring surface evapotranspiration quantity |
| CN202095371U (en) * | 2011-06-03 | 2012-01-04 | 李崇平 | Automatic spray system |
| CN102353602A (en) * | 2011-06-15 | 2012-02-15 | 中国水利水电科学研究院 | Compensating automatic measurement system and method of soil surface evaporation capacity |
| CN102696433A (en) * | 2012-07-02 | 2012-10-03 | 昆山卉友生态科技有限公司 | Automatic-irrigation heat-insulating cultivation box for plant cultivation |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106290801A (en) * | 2016-10-27 | 2017-01-04 | 中南大学 | The Apparatus and method for that soil body saturation controls |
| CN110736761A (en) * | 2019-09-28 | 2020-01-31 | 同济大学 | Visual test device and method for influence of temperature changes on subway tunnel |
| CN114167032A (en) * | 2021-11-29 | 2022-03-11 | 内蒙古科技大学 | Method and device for simulating influence of mining subsidence on soil water and salt migration |
| CN114167032B (en) * | 2021-11-29 | 2024-05-14 | 内蒙古科技大学 | Method and device for simulating influence of mining subsidence on soil water salt migration |
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Granted publication date: 20150304 Termination date: 20161112 |