CN108732331A - A kind of device tested with the soil water, vapour, heat, salt simultaneous transport for unsaturation - Google Patents

Abstract

The invention discloses a device for coupled migration test of soil water, vapor, heat and salt in an unsaturated zone, which comprises a soil column unit, an evaporation unit, a water supply unit and a monitoring unit. The soil column unit includes a soil column with an open upper end, and the outer wall of the soil column is wrapped with a thermal insulation sponge. The monitoring unit includes a monitoring system and a data acquisition system. The monitoring system includes several soil moisture-temperature-conductivity sensors and soil temperature sensors inserted into the soil column. The monitoring system is connected to the data acquisition system. Evaporation units consist of radiant lamps suspended above soil columns. The water supply unit includes a water supply device, the water supply device is installed on the supporting frame through the lifting system, and the water supply device is connected with the soil column and the peristaltic pump. The invention can easily realize the continuous monitoring of the moisture content, temperature and electrical conductivity of the unsaturated zone, so as to obtain the migration of liquid water, water vapor, heat flow and salt in the unsaturated zone. Migration distribution laws provide the necessary information.

Description

A device for coupled migration experiment of soil water, steam, heat and salt in unsaturated zone

technical field

The invention belongs to the field of groundwater environmental engineering, and in particular relates to a device for coupled migration tests of soil water, steam, heat and salt in an unsaturated zone.

Background technique

The migration and transformation between matter and energy in soil in nature is very common. Water movement, heat conversion and solute transport at any point in unsaturated soil are interrelated and interact, thus forming a complex soil hydrodynamic coupling system. Therefore, the research on the coupled transport mechanism of soil water, heat and solutes in this system has important guiding significance for agricultural production, engineering construction, salinization land treatment, monitoring and control of groundwater pollution, etc.

To this end, the migration and distribution information of soil water, heat and salt is obtained indirectly by observing the soil moisture content, temperature and electrical conductivity. Although there are experimental devices used for similar research at home and abroad, there are still the following defects: 1. The soil column itself has not been adiabatized, resulting in heat exchange between the soil column and the external environment during the test and cannot form a one-dimensional soil column experiment. 2. Many indoor experiments are carried out in closed soil columns without considering the entry of external moisture and the evaporation of soil moisture at the upper boundary, resulting in failure to consider evaporation and the soil-atmosphere interface boundary effects.

Contents of the invention

In order to solve the above problems, the present invention provides a device with strong integrity, which can simultaneously observe soil moisture, temperature, and electrical conductivity and automatically collect data, and simulate water-heat, water-steam-heat, and water-steam under the condition of evaporation. -The time-varying process of heat-salt migration, a centralized and convenient experimental device for monitoring the coupled migration of water, vapor, heat, and salt in unsaturated zone soil.

The present invention solves its technical problem and realizes through the following technical solutions:

A device for coupled migration tests of soil water, vapor, heat, and salt in an unsaturated zone, including a soil column unit, an evaporation unit, a water supply unit and a monitoring unit;

The soil column unit includes a vertically arranged soil column with an upper opening, the bottom of the soil column is sealed, and the outer wall of the soil column is wrapped with a heat-insulating sponge. Two sets of probe openings, the first set of probe openings and the second set of probe openings are arranged on both sides of the side wall of the soil column, and the first set of probe openings and the second set of probe openings are on the soil column along the soil column The central axis is arranged longitudinally from top to bottom;

The monitoring unit includes a monitoring system and a data acquisition system, the monitoring system includes several soil moisture-temperature-conductivity sensors and soil temperature sensors, and the soil moisture-temperature-conductivity sensors are inserted into the soil through the first group of probe ports column, the soil temperature sensor is inserted into the soil column through the second group of probe ports, and the soil moisture-temperature-conductivity sensor and the soil temperature sensor are connected to the data acquisition system;

The evaporation unit includes a radiation lamp suspended above the soil column;

The water supply unit includes a water supply device, the water supply device is installed on the supporting frame liftably through the lifting system, the water supply device is connected to the soil column through the first aqueduct, and the water supply device is connected to the peristaltic pump through the second aqueduct .

Further, the number of probe ports in the first group is 6, and the number of probe ports in the second group is also 6.

Further, the first group of probe ports is evenly opened on the soil column, and the second group of probe ports is also uniformly opened on the soil column, and the first group of probe ports at the top and the first group of probe ports arranged from top to bottom The two second groups of probe openings are symmetrical to each other, and the second first group of probe openings arranged from top to bottom are symmetrical to the fourth second group of probe openings arranged from top to bottom.

Further, an anti-filter layer is laid on the inner bottom of the soil column, a sealing disc is installed under the anti-filter layer, and the sealing disc is fixedly connected to the soil column outside the soil column, and a filter layer is arranged between the anti-filter layer and the sealing disc. There is barbed wire.

Further, a first water receiving port is opened at the center of the sealing plate, and the first water guide pipe is connected to the soil column through the first water receiving port.

Further, the water supply device is in the form of a double-layer water tank, the water supply device includes an outer layer water tank and an inner layer water tank arranged in the outer layer water tank, a second water receiving port is opened on the side wall of the inner layer water tank, and the outer layer water tank A water stop valve is installed on the water tank; one end of the first aqueduct is connected to the soil column through the first water connection, and the other end of the first aqueduct extends into the inner water tank through the second water connection; one end of the second aqueduct extends into the inner layer A water tank, and the other end of the second aqueduct communicates with a peristaltic pump.

Further, a pressure measuring tube is installed on the outer side wall of the lower end of the soil column.

Further, the lowest height at which the water supply device can be lowered is less than or equal to the bottom height of the soil column, and the highest height at which the water supply device can be raised is greater than or equal to the top height of the soil column.

The beneficial effects of the present invention are:

1. It can create a one-dimensional experimental simulation environment. The insulating sponge on the outer wall of the soil column isolates the heat exchange between the soil in the soil column and the external environment. Under this condition, the horizontal migration of heat flow can be ignored, and then the migration and distribution of water and salt under the influence of unidirectional temperature gradient changes can be studied.

2. It can create indoor experimental conditions for evaporation. Through the radiant lamp above the soil column, evaporation conditions can be created at the laboratory scale, and the evaporation mode can be changed by adjusting the radiant lamp.

3. Accurate and meticulous detection of soil temperature. The temperature mutual calibration through the two sensors makes the temperature monitoring more accurate, because temperature is one of the main driving forces of water, vapor and salt, so its accurate monitoring is essential.

4. The simulated groundwater level can be changed. By adjusting the lifting system on the support frame, the position of the water supply device can be changed, thereby adjusting the position of the groundwater level in the soil column, and the research on the migration and distribution of soil water, heat and salt under various water levels can be realized.

In summary, the present invention can easily realize the continuous monitoring of the moisture content, temperature and conductivity of the unsaturated zone, thereby obtaining the migration of liquid water, water vapor, heat flow and salt in the unsaturated zone. The migration and distribution of heat and salt provide the necessary information.

Description of drawings

Fig. 1 is the overall structural representation of the present invention;

Fig. 2 is the structural representation of soil column in the present invention;

Fig. 3 is the structural representation of sealing disc among the present invention;

Fig. 4 is a schematic structural view of the water supply device in the present invention.

Explanation of reference signs:

1-soil column, 2-lifting system, 3-water supply device, 4-first aqueduct, 5-support frame, 6-monitoring system, 7-data acquisition system, 8-radiant lamp, 9-soil moisture-temperature- Conductivity sensor, 10-soil temperature sensor, 11-first group of probe ports, 12-second group of probe ports, 13-second aqueduct, 14-peristaltic pump, 15-insulation sponge, 16-reverse filter layer, 17 - the first water connection, 18 - the second water connection, 19 - pressure measuring tube, 20 - sealing plate, 21 - barbed wire, 22 - water stop valve.

Detailed ways

The present invention will be further described in detail below through the specific examples, the following examples are only descriptive, not restrictive, and cannot limit the protection scope of the present invention with this.

As shown in Figure 1, a device for coupled migration experiments of soil water, vapor, heat, and salt in the unsaturated zone includes a soil column unit, an evaporation unit, a water supply unit and a monitoring unit.

As shown in Figures 1 to 3, the soil column unit includes a vertically arranged soil column 1, and the material of the soil column 1 is acrylic. The upper end of the soil column 1 is open to ensure that the water in the soil column can be evaporated. The outer wall of the soil column 1 is wrapped with a heat-insulating sponge 15. The heat-insulating sponge 15 isolates the heat exchange between the soil in the soil column 1 and the external environment. Under this condition, the horizontal transfer of heat flow can be ignored. The distribution of migration under the influence of changes. A reverse filter layer 16 is laid on the bottom of the inner side of the soil column 1. The reverse filter layer 16 of the present invention uses gravel and coarse sand as filter materials. The bottom of the reverse filter layer 16 is sealed by installing a sealing disc 20, and the sealing disc 20 is fixed outside the soil column 1. The soil column 1 is connected by screws, a barbed wire 21 is provided between the reverse filter layer 16 and the sealing disc 20 , and a first water receiving port 17 is provided at the center of the sealing disc 20 . The effect of the barbed wire 21 is mainly to prevent the upper fine sand from entering the reverse filter layer 16 during the filling process and blocking the first water receiving port 17.

A piezometric tube 19 is installed on the outer wall of the lower end of the soil column 1 , and the saturation degree of the soil in the soil column 1 is observed through the piezometric tube 19 . The side wall of the soil column 1 is evenly provided with several first group probe ports 11 and second group probe ports 12. The present invention adopts six first group probe ports 11 and six second group probe ports 12, and the first group probe ports 11 and the second group of probe ports 12 are arranged on both sides of the side wall of the soil column 1, and the first group of probe ports 11 and the second group of probe ports 12 are vertically arranged on the soil column 1 from top to bottom. The topmost first group of probe ports 11 is symmetrical to the second second group of probe ports 12 arranged from top to bottom, and the second first group of probe ports 11 arranged from top to bottom and the second group of probe ports 11 arranged from top to bottom are symmetrical to each other. The fourth second group of probes 12 are symmetrical to each other, and the distance between the soil temperature sensors 10 is half of the distance between the soil moisture-temperature-conductivity sensors 9 . The invention uses two kinds of sensors to compare the temperature with each other, and encrypts the temperature measurement, because the main factor affecting the migration of moisture and salt in the soil is temperature.

As shown in FIGS. 1 and 2 , the monitoring unit includes a monitoring system 6 and a data acquisition system 7 , and the monitoring system 6 includes six soil moisture-temperature-conductivity sensors 9 and six soil temperature sensors 10 . The soil moisture-temperature-conductivity sensor 9 is inserted into the soil column 1 through the first set of probe ports 11, the soil temperature sensor 10 is inserted into the soil column 1 through the second set of probe ports 12, the soil moisture-temperature-conductivity sensor 9 and the soil temperature sensor 10 are all connected to the data acquisition system 7.

As shown in Figure 1, the evaporation unit includes a radiation lamp 8, which is suspended above the soil column 1. The radiation lamp 8 can provide the conditions for water evaporation in the soil column, simulate the evaporation environment, and change the evaporation mode by adjusting the radiation lamp .

As shown in Figure 1 and Figure 4, the water supply unit includes a water supply device 3, the water supply device 3 is in the form of a double-layer water tank, the water supply device 3 includes an outer layer of water tank and an inner layer of water tank arranged in the outer layer of water tank, on the side wall of the inner layer of water tank A second water receiving port 18 is provided. The water supply device 3 communicates with the soil column 1 through the first aqueduct 4 , one end of the first aqueduct 4 communicates with the soil column 1 through the first water connection 17 , and the other end of the first aqueduct 4 extends into the inner tank through the second water connection 18 . The water supply device 3 communicates with the peristaltic pump 14 through the second water guide pipe 13 , one end of the second water guide pipe 13 extends into the inner tank, and the other end of the second water guide pipe 13 communicates with the peristaltic pump 14 . The inner layer water tank can overflow to the outer layer water tank after the water is full, and the water stop valve 22 is installed on the outer layer water tank, which can discharge unnecessary overflow water. The water supply device 3 is installed on the support frame 5 through the lifting system 2, and the position of the water supply device 3 can be changed by adjusting the lifting system 2 on the support frame 5, thereby adjusting the position of the groundwater level in the soil column 1, which can realize Research on the migration and distribution of soil water, heat and salt under various water levels. The minimum height at which the water supply device 3 can be lowered is less than or equal to the bottom height of the soil column 1, and the maximum height at which the water supply device 3 can be raised is greater than or equal to the top height of the soil column 1.

The using method of device of the present invention is as follows:

(1) Lay barbed wire 21 on the sealing disc 20 at the bottom of the soil column 1, and lay an anti-filter layer 16 on the top of the barbed wire 21.

(1) Fill the soil sample into the soil column 1. When filling the soil sample, the bulk density of each place in the soil column 1 should be kept the same.

(3) When the soil sample is filled to a certain height, install and insert the soil moisture-temperature-conductivity sensor 9 and the soil temperature sensor 10 .

(4) Seal the pores around the soil moisture-temperature-conductivity sensor 9 and the soil temperature sensor 10 with a sealant.

(5) After filling the soil samples and installing the sensors, wrap the outside of the soil column 1 with 2 to 3 layers of heat-insulating sponge material, and stagger the interface positions of the soil moisture-temperature-conductivity sensor 9 and the soil temperature sensor 10 .

(6) Connect the soil moisture-temperature-conductivity sensor 9 and the soil temperature sensor 10 to the automatic data acquisition system 7 .

(7) Use the lifting system 2 to adjust the water supply device 3 to a position close to the soil surface.

(8) Prepare the salt solution for the experiment.

(9) Turn on the peristaltic pump 14 to fill the inner tank of the water supply device 3 with the configured solution, and continue for a period of time to saturate the soil in the soil column. After the soil saturation is observed through the piezometric tube 19, the peristaltic pump 14 is turned off and the automatic data acquisition system 7 is turned on. Let stand for a period of time, wait for the gravity drainage to complete, and naturally form an unsaturated zone.

(10) Turn on the radiation lamp 8, collect and obtain data through the automatic data collection system 7, the data included include soil temperature T, soil water content θ, and soil electrical conductivity. The whole process lasts for 72 hours or more.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (8)

1. a kind of device tested with the soil water, vapour, heat, salt simultaneous transport for unsaturation, it is characterised in that：Including earth pillar list Member, evaporation element, water supplying unit and monitoring unit；

The earth pillar unit includes the earth pillar (1) that upper end opening is vertically arranged, earth pillar (1) sealed bottom, the earth pillar (1) Lateral wall is enclosed with adiabatic sponge (15), and earth pillar (1) side wall offers several first group of probe mouth (11) and second group Probe mouth (12), first group of probe mouth (11) are oppositely arranged on earth pillar (1) side wall both sides with second group of probe mouth (12), and First group of probe mouth (11) and second group of probe mouth (12) on earth pillar (1) along the central shaft of earth pillar (1) from top to bottom Longitudinal arrangement；

The monitoring unit includes monitoring system (6) and data collecting system (7), and the monitoring system (6) includes several soil Earth moisture-temperature-conductivity sensor (9) and soil temperature sensor (10), the soil moisture-temperature-conductivity sensors Device (9) is inserted into earth pillar (1) by first group of probe mouth (11), and the soil temperature sensor (10) passes through second group of probe mouth (12) it is inserted into earth pillar (1), the soil moisture-temperature-conductivity sensor (9) and soil temperature sensor (10) are all connected with number According to acquisition system (7)；

The evaporation element includes radial burner (8), and the radial burner (8) is suspended on above earth pillar (1)；

The water supplying unit includes water supply installation (3), and the water supply installation (3) is mounted on by the way that jacking system (2) is liftable On supporting rack (5), the water supply installation (3) is connected to earth pillar (1) by the first aqueduct (4), and the water supply installation (3) passes through the Two aqueducts (13) are communicated with peristaltic pump (14).

2. a kind of device tested with the soil water, vapour, heat, salt simultaneous transport for unsaturation as described in claim 1, special Sign is：The number of first group of probe mouth (11) is 6, and the number of second group of probe mouth (12) is also 6.

3. a kind of device tested with the soil water, vapour, heat, salt simultaneous transport for unsaturation as claimed in claim 2, special Sign is：First group of probe mouth (11) is uniformly opened on earth pillar (1), and second group of spy mouth (12) is also uniformly opened in On earth pillar (1), first group of probe mouth (11) of the top and second second group of spy mouth (12) phase arranged from top to bottom It is mutually symmetrical, described second first group of probe mouth (11) up to lower arrangement and the 4th second group of spy mouth arranged from top to bottom (12) symmetrically.

4. a kind of device tested with the soil water, vapour, heat, salt simultaneous transport for unsaturation as described in claim 1, special Sign is：Earth pillar (1) inside bottom is equipped with loaded filter (16), and seal disc is equipped with below the loaded filter (16) (20), the seal disc (20) is fixedly connected with earth pillar (1) outside earth pillar (1), between the loaded filter (16) and seal disc (20) Equipped with wire netting (21).

5. a kind of device tested with the soil water, vapour, heat, salt simultaneous transport for unsaturation as claimed in claim 4, special Sign is：The first water inlet (17) is offered at the center of the seal disc (20), first aqueduct (4) connects by first The mouth of a river (17) is connected to earth pillar (1).

6. a kind of device tested with the soil water, vapour, heat, salt simultaneous transport for unsaturation as described in claim 1, special Sign is：The water supply installation (3) is double-layer water tank form, and the water supply installation (3) includes outer layer sink and is set to outer layer Internal layer sink in sink offers the second water inlet (18) on internal layer basin sidewall, sealing is equipped on the outer layer sink Valve (22)；First aqueduct (4) one end is connected to earth pillar (1) by the first water inlet (17), and the first aqueduct (4) other end passes through Second water inlet (18) stretches into internal layer sink；Internal layer sink, the second aqueduct (13) are stretched into described second aqueduct (13) one end The other end is connected to peristaltic pump (14).

7. a kind of device tested with the soil water, vapour, heat, salt simultaneous transport for unsaturation as described in claim 1, special Sign is：The lateral wall of earth pillar (1) lower end is equipped with pressure-measuring pipe (19).

8. a kind of device tested with the soil water, vapour, heat, salt simultaneous transport for unsaturation as described in claim 1, special Sign is：The minimum altitude that the water supply installation (3) can decline is less than or equal to the bottom level of earth pillar (1), the water supply dress Set (3) can raised maximum height be greater than or equal to earth pillar (1) overhead height.