Moisture migration experimental device suitable for huge thick aeration zone

Abstract

The utility model discloses a moisture migration experimental device suitable for a huge thick aeration zone, which belongs to the technical field of aeration zone moisture migration and comprises a soil tank, a double-ring test is arranged at the bottom of the soil tank, is used for measuring the vertical permeability coefficient of a sandy gravel layer below a fine soil layer and is arranged at the bottom of the soil tank; and a plurality of negative pressure meters, soil moisture testers, soil moisture extractors and thermometers are buried in three wall surfaces of the soil tank. The negative pressure meter, the soil moisture tester and the thermometer are arranged in the soil tank in a reasonable manner, and the sensors are connected with the automatic data acquisition unit, so that the moisture migration conditions of the soil at different depths in the extremely thick aeration zone can be accurately monitored for a long time. The device can ensure accurate measurement and analysis of soil moisture by accurately arranging monitoring equipment, so that the migration conditions of soil moisture at different depths can be clearly reflected.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of vadose zone moisture migration, more particularly to a moisture migration experimental device suitable for thick vadose zone. BACKGROUND

[0002] The vadose zone is an important link in the hydrological cycle. Atmospheric precipitation or surface water infiltrates into groundwater through the vadose zone, while shallow groundwater evaporates to the surface through the vadose zone. These processes affect the formation and transformation of groundwater resources. In addition, surface pollutants can enter the aquifer through the vadose zone, causing groundwater pollution problems.

[0003] When revealing the mechanism of vadose zone moisture migration, comprehensive methods such as indoor numerical simulation, field or in-situ monitoring are usually used. The in-situ monitoring device can obtain vadose zone moisture migration data under natural conditions. Existing in-situ vadose zone soil moisture migration experimental devices are mostly suitable for relatively small thickness of the vadose zone. In thick vadose zone, the complexity of its thickness and geological conditions leads to a significant increase in soil moisture migration time, more significant influence of temperature gradient, and a significant increase in monitoring difficulty.

[0004] The existing moisture migration experimental device often faces the following problems: due to the differences in soil type, level and structure, the conventional soil moisture test method is difficult to obtain comprehensive and accurate moisture migration data when monitoring thick vadose zone. Some existing devices lack effective data collection and storage systems, making it impossible to conduct long-term stable moisture monitoring, limiting in-depth analysis of soil moisture dynamic changes. Many moisture migration experimental devices can only simulate simplified soil environment and are difficult to simulate complex soil layers and moisture migration processes in natural environment, so their application range and reliability are limited. Traditional experimental devices often ignore the effects of external factors such as weather and groundwater level, resulting in experimental results lacking comprehensiveness and failing to fully reveal the relationship between soil moisture migration and these factors.

[0005] Therefore, there is an urgent need for a new experimental device that can accurately monitor the dynamic changes of soil moisture in thick vadose zone under actual soil conditions through a precisely arranged sensor system and automatic data acquisition equipment, and consider the effects of weather conditions and groundwater level changes on the moisture migration process. SUMMARY

[0006] 1. Technical problem to be solved

[0007] In view of the problems existing in the prior art, the purpose of the utility model is to provide a moisture migration experimental device suitable for thick vadose zone, which can accurately monitor the moisture migration of thick vadose zone at different depths for a long time, effectively prevent the interference of external environment, and realize long-term stable moisture migration monitoring.

[0008] 2. Technical solutions

[0009] To solve the above problems, the utility model adopts the following technical scheme.

[0010] A water migration experiment device suitable for thick vadose zone, comprising a soil tank, a double-ring test is arranged at the bottom of the soil tank and used for measuring the vertical permeability coefficient of the sand and pebble layer below the fine soil layer; a plurality of negative pressure gauges, soil moisture testers, soil moisture extractors and thermometers are buried in the three walls of the soil tank.

[0011] The negative pressure gauge is connected with soil water through a ceramic head and is used for measuring the matric potential of soil water; the soil moisture tester and the extractor are used for monitoring the soil moisture content; and the thermometer is used for measuring the soil temperature.

[0012] An observation chamber is arranged on the side of the soil tank and has a rectangular plane top surface and a depth of about 2m, and is used for placing an automatic data collector, a tray with a placing groove, a vacuum pump and a plurality of water sample bottles; the water sample bottles are provided with scales and are placed in the placing grooves of the tray; a small weather station is arranged near the soil tank and is used for automatically monitoring the weather; and a self-counting water level gauge is used for observing the underground water level in a water level observation well near the soil tank.

[0013] According to the above features, the double-ring test has an outer ring and an inner ring; a water tank with scales is connected with the outer ring and the inner ring through water outlet rubber pipes; an electromagnetic valve is connected with the water outlet rubber pipes; the electromagnetic valve is sequentially connected with a controller and a water level sensor, so that the water levels of the inner ring and the outer ring are kept consistent.

[0014] In some embodiments, the negative pressure gauges are buried in one side wall of the soil tank; the soil moisture testers are buried in the wall adjacent to the position where the negative pressure gauges are buried; the soil moisture extractors are dispersedly buried in the three walls of the soil tank; and the thermometers are buried in the wall of the soil tank on the same side as the negative pressure gauges.

[0015] According to the above features, the negative pressure gauges are arranged in the following manner in the side wall of the soil tank: one is buried every 5cm in the range of 0-0.1m, one is buried every 10cm in the range of 0.1-0.8m, one is buried every 20cm in the range of 0.8-2.2m, and one is buried every 40cm below 2.2m, and the horizontal spacing is 10cm; and the soil moisture testers are arranged in the following manner in the side wall of the soil tank: one is buried at 0.05m, 0.1m, 0.3m, 0.6m and 1.0m in the range of 0-1m, and one is buried every 0.6m below 1m, and the horizontal spacing is 10cm.

[0016] In some embodiments, the negative pressure gauges are WM-1 type ceramic head negative pressure gauges, and the soil moisture testers are CS615 type soil moisture testers.

[0017] Based on the above characteristics, the soil moisture extractor is installed on the side wall of the soil trough in the following manner: one is buried every 50cm vertically; the thermometer is installed on the side wall of the soil trough in the following manner: one is buried every 5cm from 0 to 0.3m, one is buried every 10cm from 0.3 to 0.5m, one is buried every 20cm from 0.5 to 0.9m, and one is buried every 30cm from 0.9 to 1.5m, with a horizontal spacing of 10cm.

[0018] In some implementations, the probes of the negative pressure gauge, soil moisture tester, and thermometer are all connected to the automatic data acquisition unit via conduits that pass through the side wall of the observation chamber.

[0019] Based on the above features, the soil moisture extractor is connected to a pressure pipe and a water outlet rubber pipe. The pressure pipe and the water outlet rubber pipe pass through the side wall of the observation chamber and are respectively connected to a vacuum pump and a water sample bottle. The pressure pipe and the water outlet rubber pipe are equipped with valves.

[0020] 3. Beneficial effects

[0021] Compared with existing technologies, the advantages of this utility model are:

[0022] 1) This utility model arranges negative pressure gauges, soil moisture testers and thermometers in a reasonable manner in the soil trough, and connects these sensors to an automatic data acquisition device, which can accurately monitor the movement of soil moisture at different depths in the thick vadose zone for a long time.

[0023] 2) By precisely deploying monitoring equipment, this device can ensure accurate measurement and analysis of soil moisture, thus clearly reflecting the movement of soil moisture at different depths.

[0024] 3) The double-ring test design in this invention ensures a constant water level, avoiding the impact of water level fluctuations on the experimental results and thus improving the accuracy of vertical permeability coefficient measurement. Furthermore, all sensor data is recorded in real-time by an automatic data acquisition unit, ensuring the stability and accuracy of data acquisition and reducing errors from manual operation.

[0025] 4) The observation chamber of this utility model, through its closed and locked design, effectively prevents interference from the external environment and enables long-term and stable monitoring of water migration. Attached Figure Description

[0026] Fig. 1 This is a schematic diagram of the structure of an experimental device for water transport suitable for a very thick vadose zone according to the present invention.

[0027] Fig. 2 This is a schematic diagram of the arrangement of the soil moisture extractor of this utility model.

[0028] The components include: 1. Soil trough; 2. Observation room; 3. Weather station; 4. Observation well; 5. Negative pressure gauge; 6. Soil moisture tester; 7. Soil moisture extractor; 8. Thermometer; 9. Wire; 10. Air pressure pipe; 11. Water outlet rubber hose; 12. Automatic data acquisition device; 13. Small vacuum pump; 14. Tray; 15. Water sample bottle; 16. Switch valve; 17. Self-counting water level gauge; 18. Outer ring; 19. Inner ring; 20. Graduated water tank; 21. Solenoid valve; 22. Controller; 23. Water level sensor. Detailed Implementation

[0029] The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, what is described is only a part of the embodiments of this utility model, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0030] Example 1:

[0031] Please see Figs. 1-2 An experimental device for water transport suitable for a very thick vadose zone includes a soil trough 1, located in the in-situ test site, 1m wide and 2.5m long, excavated to the bottom boundary of the fine soil layer of the vadose zone, reaching a stable and continuous sand and gravel layer, with a depth of about 4m.

[0032] A double-ring test at the bottom of the test pit is used to measure the vertical permeability coefficient of the sand and gravel layer below the fine soil layer. It is set at the bottom of the soil trough 1. Several negative pressure gauges 5, soil moisture testers 6, soil moisture extractors 7 and thermometers 8 are buried on the three walls of the soil trough 1. The negative pressure gauges 5 establish a connection with the soil water through the clay head to measure the matric potential of the soil water. The soil moisture testers 5 and extractors 6 are used to monitor the soil moisture content. The thermometers 7 are used to measure the soil temperature.

[0033] Observation chamber 2, approximately 2m in length, width, and depth, is located on the side of the earthen trough 1. It houses the automatic data acquisition device 12, a tray 14 with placement slots, a vacuum pump 13, and several water sample bottles 15. The water sample bottles are graduated and placed in the placement slots of the tray. The walls and floor of the observation chamber are to be lined (with bricks and cement) and sealed with a lock.

[0034] Watchdog was selected as the small weather station 3 and placed near the earthen trench for automatic weather monitoring; Diver was selected as the self-recording water level gauge 17 and groundwater level was observed in the water level observation well 4 near the earthen trench; after the soil was backfilled, the earthen trench was backfilled after all the test equipment was debugged.

[0035] Soil samples were collected during the excavation of trench 1 for indoor particle and soluble salt analysis. In the double-ring experiment, the outer ring 18 had a diameter of 0.4m, the inner ring 19 had a diameter of 0.2m, and both were 0.3m high. A graduated water tank 20 was connected to a water outlet rubber hose 11 to inject water into the outer ring 18 and the inner ring 19 respectively. A solenoid valve 21 was connected to the water outlet rubber hose 11, and the solenoid valve 21 was connected to the controller 22 and the water level sensor 23 in sequence to keep the water level of the inner and outer rings at the same height at all times. A negative pressure gauge 5 was buried in the side wall of trench 1, which was 2.5m long. A soil moisture tester 6 was buried in the trench wall adjacent to the location of the negative pressure gauge. Soil moisture extractors 7 were scattered on three walls of the trench. A thermometer 8 was buried in the trench wall on the same side as the negative pressure gauge.

[0036] The negative pressure gauges 5 are arranged longitudinally on the sidewalls of the soil trench as follows: one gauge is buried every 5 cm within 0-0.1 m, one every 10 cm within 0.1-0.8 m, one every 20 cm between 0.8-2.2 m, and one every 40 cm below 2.2 m. The lateral spacing is 10 cm. The soil moisture testers 6 are arranged longitudinally on the sidewalls of the soil trench as follows: one tester is buried at 0.05 m, 0.1 m, 0.3 m, 0.6 m, and 1.0 m within 0-1 m, and one every 0.6 m below 1 m. The lateral spacing is 10 cm. The negative pressure gauges 5 are WM-1 type clay head negative pressure gauges, and the soil moisture testers 6 are CS615 type soil moisture testers.

[0037] Soil moisture extractors 7 are installed on the sidewalls of the soil trough with a vertical spacing of one 7-1 every 50cm. Thermometers 8 are installed on the sidewalls of the soil trough with a spacing of one thermometer every 5cm from 0-0.3m, one every 10cm from 0.3-0.5m, one every 20cm from 0.5-0.9m, and one every 30cm from 0.9-1.5m, with a horizontal spacing of 10cm. Several negative pressure gauges 5, soil moisture testers 6, and thermometer 8 probes are all connected to conduits 9, which pass through the sidewalls of the observation chamber and connect to the automatic data acquisition unit 12. Several soil moisture extractors 7 are all connected to air pressure pipes 10 and water outlet rubber pipes 11, which pass through the sidewalls of the observation chamber and connect to a vacuum pump 13 and a water sample bottle 15, respectively. Both the air pressure pipe and the water outlet rubber pipe are equipped with valves 16.

[0038] The excavation trench 1 penetrates the entire thick vadose zone, and negative pressure gauges 5, soil moisture meters 6 and 7, and thermometers 8 are installed at appropriate intervals from shallow to deep along the trench sidewalls. This arrangement overcomes the challenges of the thick vadose zone, slow water transport, and complex geological structure, accurately monitoring relevant parameters of water transport in the thick vadose zone and providing a direct view of soil water transport at different depths. The observation chamber 2 houses the automatic data acquisition unit 12 and other monitoring equipment. The walls and floor of the observation chamber 2 are lined and sealed with a waterproof cap, enabling long-term observation. A small weather station 3 performs automatic meteorological monitoring, analyzing the impact of changes in meteorological elements such as rainfall, evaporation, and temperature on the water transport process in the vadose zone. Furthermore, monitoring the groundwater level changes in nearby observation wells 4 allows for analysis of the relationship between water transport in the vadose zone and groundwater level changes.

[0039] Working Principle: This experimental setup uses various monitoring devices within soil trough 1 to monitor and analyze the movement of soil moisture in the vadose zone in real time. Soil trough 1 is equipped with a manometer, soil moisture meter, soil moisture extractor, and thermometer, capable of measuring key parameters such as soil matrix potential, moisture content, and temperature. These sensors provide soil moisture data at different depths and locations, helping to understand the spatial and temporal variations in soil moisture movement within the vadose zone. The manometer measures the matrix potential of soil water by establishing a connection with the soil water through a clay head, measuring the potential energy of the water in the soil. These measurements help determine the direction and rate of water movement. The manometers are deployed in a combination of longitudinal and lateral configurations, enabling data collection at different depths and locations. The soil moisture meter measures the moisture content in the soil using the principle of capacitance, while the soil moisture extractor extracts moisture samples from the soil using physical methods (such as utilizing pressure difference or vacuum). These devices provide quantitative data on soil moisture and, combined with data from other sensors, analyze the vertical and lateral distribution of moisture. Thermometers are used to monitor soil temperature changes, as temperature significantly affects soil moisture transport, especially under different seasons and climatic conditions. Real-time measurement of soil temperature at different depths provides more clues to the patterns of moisture transport. The double-loop experiment is used to measure the vertical permeability coefficient of soil. By applying a certain water pressure to the soil and measuring the rate of water infiltration, the soil permeability coefficient can be calculated. The experiment uses an outer loop and an inner loop, and by controlling the water level to remain constant, the impact of water level fluctuations on the experimental results is reduced.

[0040] Data from various sensors (barometers, soil moisture meters, thermometers, etc.) is transmitted via conduit 9 to an automatic data logger 12 in observation chamber 2, recording changes in soil moisture and temperature in real time. The data logger periodically collects and saves data for further analysis. A small weather station 3 provides meteorological data, including precipitation, evaporation, and air temperature. This meteorological data helps analyze the impact of these factors on moisture transport in the vadose zone. Groundwater level monitoring well 4 monitors changes in groundwater level via a Diver level gauge 17, analyzing the relationship between groundwater level and moisture transport in the vadose zone. Observation chamber 2 is equipped with a closed system to prevent external interference and ensure the accuracy and long-term stability of data acquisition. A pressure pipe and rubber tubing connect the soil moisture extractor to a vacuum pump and a water sample bottle, extracting soil moisture samples and storing them in the water sample bottle for later analysis.

[0041] The above description is merely a preferred embodiment of this utility model; however, the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and its improved concept, should be included within the protection scope of this utility model.

Claims

1. An experimental apparatus for water transport in a thick vadose zone, comprising a soil trough (1), characterized in that: The bottom of the soil trough (1) is equipped with a double-ring test to measure the vertical permeability coefficient of the sand and gravel layer below the fine soil layer, and is set at the bottom of the soil trough; several negative pressure gauges (5), soil moisture testers (6), soil moisture extractors (7) and thermometers (8) are buried on the three walls of the soil trough (1). The negative pressure gauge (5) establishes a connection with the soil water through the clay head to measure the matrix potential of the soil water. The soil moisture tester (6) and extractor (7) are used to monitor the soil moisture content. The thermometer (8) is used to measure the soil temperature. The observation room (2) has a rectangular plane on its top surface and a depth of about 2m. It is located on the side of the earthen trough (1) and is used to place an automatic data acquisition device (12), a tray (14) with a placement slot, a vacuum pump (13) and several water sample bottles (15). The water sample bottles (15) are graduated and placed in the placement slot of the tray. A small weather station (3) is placed near the earthen trough to carry out automatic meteorological monitoring. A self-recording water level gauge (17) is used to observe the groundwater level in the water level observation well (4) near the earthen trough.

2. The experimental apparatus for water transport suitable for a very thick vadose zone according to claim 1, characterized in that: The dual-ring test has an outer ring (18) and an inner ring (19). A graduated water tank (20) injects water into the outer ring (18) and the inner ring (19) respectively through a water outlet rubber tube (11). A solenoid valve (21) is connected to the water outlet rubber tube (11). The solenoid valve (21) is connected to the controller (22) and the water level sensor (23) in sequence, so that the water levels of the inner ring and the outer ring are kept consistent.

3. The experimental apparatus for water transport suitable for a very thick vadose zone according to claim 1, characterized in that: The negative pressure gauge (5) is buried in one side wall of the soil trough (1), the soil moisture tester (6) is buried in the trough wall adjacent to the location where the negative pressure gauge is buried, the soil moisture extractor (7) is buried in three walls of the soil trough, and the thermometer (8) is buried in the soil trough wall on the same side as the negative pressure gauge.

4. The experimental apparatus for water transport in a very thick vadose zone according to claim 3, characterized in that: The negative pressure gauge (5) is arranged on the side wall of the soil trough as follows: one is buried every 5cm from 0 to 0.1m, one is buried every 10cm from 0.1 to 0.8m, one is buried every 20cm from 0.8 to 2.2m, and one is buried every 40cm below 2.2m, with a horizontal spacing of 10cm. The soil moisture tester (6) is arranged on the side wall of the soil trough as follows: one is buried at 0.05m, 0.1m, 0.3m, 0.6m, and 1.0m within the longitudinal range of 0 to 1m, and one is buried every 0.6m below 1m, with a horizontal spacing of 10cm.

5. The experimental apparatus for water transport in a very thick vadose zone according to claim 4, characterized in that: The negative pressure gauge (5) is a WM-1 type clay head negative pressure gauge, and the soil moisture tester (6) is a CS615 type soil moisture tester.

6. The experimental apparatus for water transport in a very thick vadose zone according to claim 3, characterized in that: The soil moisture extractor (7) is installed on the side wall of the soil trough in the following manner: one is buried every 50cm vertically (7-1); the thermometer (8) is installed on the side wall of the soil trough in the following manner: one is buried every 5cm from 0 to 0.3m, one is buried every 10cm from 0.3 to 0.5m, one is buried every 20cm from 0.5 to 0.9m, one is buried every 30cm from 0.9 to 1.5m, and the horizontal spacing is 10cm.

7. The experimental apparatus for water transport in a very thick vadose zone according to claim 3, characterized in that: The probes of the negative pressure gauge (5), soil moisture tester (6) and thermometer (8) are all connected to the automatic data acquisition unit (12) through a conduit (9), which passes through the side wall of the observation room.

8. The experimental apparatus for water transport in a very thick vadose zone according to claim 6, characterized in that: The soil moisture extractor (7) is connected to the air pressure pipe (10) and the water outlet rubber pipe (11). The air pressure pipe and the water outlet rubber pipe pass through the side wall of the observation chamber and are respectively connected to the vacuum pump (13) and the water sample bottle (15). The air pressure pipe and the water outlet rubber pipe are equipped with valves (16).

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