Complete system for studying and testing the laws of water and salt transport in coastal soils

Abstract

The present invention relates to a complete system for studying and testing the law of water and salt migration in coastal soil. A base is fixed on the foot, an outer tube and an inner tube are fixed on the base, an inner tube vent valve and an outer tube vent valve are arranged on the base, a water permeable hole is opened on the inner tube, an outer tube top plate is fixed on the upper end of the outer tube, an air pressure balance pipe is fixed on the outer tube top plate, the other end of the pipe is connected to the air guide hole, a soil sampling hole is opened on the inner tube above the outer tube top plate, a liquid level controller is fixed on the outer tube top plate, a water inlet pipe is fixed on the liquid box, a liquid adding pipe is fixed on the outer tube top plate, a peristaltic pump is connected with the liquid adding pipe and the water inlet pipe, and a vent hole is arranged on the top cover plate of the liquid box. The present invention can comprehensively analyze the planting conditions of original soil and imported soil in saline-alkali areas, so as to take corresponding design schemes and operation management methods in a targeted manner, which is of great significance to the technical selection and facility operation and maintenance of sponge city construction involving soil and plants in saline-alkali areas.

Description

Technical Field

[0001] The present invention relates to the field of sponge cities, and in particular to a complete system for studying and testing the law of water and salt migration in soil in coastal areas. Background Art

[0002] In recent years, the degree of soil salinization in my country has continued to increase, especially in arid and semi-arid coastal areas. Highly salinized soil has seriously affected agricultural production and brought great difficulties to the improvement of the landscape environment. As a new concept and new model for urban construction in the new era, sponge city emphasizes the protection of the original urban ecosystem, the restoration of the water environment, and the restoration of the landscape ecology. It requires the use of various means such as vertical, plants, and soil to control rainwater pollution, alleviate urban waterlogging, and restore hydrological conditions. In the context of the country's vigorous promotion of sponge city construction, how to build sponge cities in saline-alkali areas has become a difficult problem facing many cities. The starting point for solving this problem is to organically combine the research on soil moisture, salt migration and soil improvement in saline-alkali land with the construction of sponge cities.

[0003] At present, most of the research on soil water and salt migration is concentrated in the agricultural field. The devices used are generally simple soil columns connected to salt water. The automation and integration are not high, and it is difficult to simulate the actual situation of the groundwater-soil interface more realistically. In addition, there is a lack of comprehensive consideration of the differences in soil water and salt migration under conditions such as saline-alkali soil and guest soil (planting soil) and whether plants are planted. It is not very instructive for the selection of sponge city construction technology in saline-alkali areas.

[0004] The construction of sponge cities in saline-alkali areas faces problems such as high groundwater levels and severe soil salinization. First of all, it is necessary to understand the groundwater level in the area and the migration of groundwater in the soil, so as to design the excavation depth of sponge facilities in a targeted manner. In addition, for the general practice of planting foreign soil in saline-alkali areas, it is also necessary to study the possible impact of groundwater on the planting soil under high groundwater levels and analyze the migration law of water and salt in the planting soil. At the same time, explore the changes in the migration law of groundwater moisture and salt in the soil and the impact on plant growth when planting plants. This is of great significance for guiding the rational selection of sponge city construction technology, facility design and operation management in saline-alkali areas. Summary of the invention

[0005] The purpose of the present invention is to solve the problems that the current devices used for studying the laws of water and salt migration in soil lack the authenticity of groundwater and soil simulation, the automation and integration are not high, the research methods are not comprehensive and systematic, and there is a lack of guidance for the selection of technology, design and operation management of sponge city construction in saline-alkali areas. A complete system for studying and testing the laws of water and salt migration in soil in coastal areas is provided.

[0006] According to the technical solution provided by the present invention, the complete system for studying and testing the water and salt migration law in the soil of coastal areas has a base fixed on the bottom foot, an outer tube and an inner tube fixed on the upper surface of the base, the diameter of the base is larger than the diameter of the outer tube, the inner tube is located inside the outer tube, an inner tube vent valve is provided on the base within the corresponding inner tube range, an outer tube vent valve is provided on the base between the corresponding inner tube and the outer tube, a water permeable hole is opened on the inner tube near the base, an outer tube top plate is fixed on the upper end of the outer tube, the connection between the outer tube top plate and the inner tube and the base and the inner tube are all sealed, an air pressure balance pipe is fixed on the outer tube top plate, and an outer tube vent valve is provided on the outer tube. An air guide hole is opened on the inner tube above the tube top plate, the other end of the air pressure balance tube is connected to the air guide hole, a soil sampling hole is opened on the inner tube above the outer tube top plate, a liquid level controller is fixed on the outer tube top plate, a liquid tank is provided on one side of the outer tube, a water inlet pipe is fixed on the top cover plate of the liquid tank, a liquid adding pipe is fixed on the outer tube top plate, the water outlet end of the liquid adding pipe extends into the outer tube, the water inlet end of the water inlet pipe extends into the liquid tank, the water outlet end of the peristaltic pump is connected to the water inlet end of the liquid adding pipe, the water inlet end of the peristaltic pump is connected to the water outlet end of the water inlet pipe, the liquid level controller is connected to the peristaltic pump, and an air vent is provided on the top cover plate of the liquid tank.

[0007] The diameter of the outer tube is 400-600 mm, and the height of the outer tube is 300-500 mm.

[0008] The diameter of the inner tube is 150-250 mm, and the height of the inner tube is 1200-1800 mm.

[0009] An elastic sealing flap is fixed on the inner wall of the air-permeable hole.

[0010] The diameter of the base is 450-650 mm.

[0011] The liquid level controller is of float type, and the floating range of the float is 2~38cm.

[0012] The height of the water-permeable hole from the bottom end of the inner tube is 8-12 mm, the diameter of the water-permeable hole is 7-9 mm, and the number of the water-permeable holes is 8-12.

[0013] The distance between the center of the air guide hole and the top plate of the outer tube is 8-12 mm, and the diameter of the air guide hole is 8-12 mm.

[0014] The diameter of the soil sampling holes is 8~12mm. The soil sampling holes are arranged at two points along the circumferential diameter of the inner tube, two in a group, and the adjacent groups are vertical with an interval of 40~60mm. The soil sampling holes are generally distributed in a cross shape along the circumference of the inner tube. The distance between the bottom group of sampling holes and the top plate of the outer tube is 40~60mm. A total of 18~22 groups of soil sampling holes are arranged.

[0015] The present invention has the following advantages:

[0016] 1. The simulation of groundwater and soil is highly realistic, and the system integration and automation are high. The concentric and bottomed cylinders involved in the present invention have an inner column that is a soil column and an outer column that is a groundwater simulation column. The bottoms of the two are connected through small water holes, which simulates the actual situation of the interface between groundwater and soil more realistically. Through the liquid level controller set on the outer column, the liquid level change and the start and stop of the pump liquid system are linked to realize automatic control of the groundwater level, and the groundwater level can be set by itself, with a high degree of automation and strong flexibility. At the same time, factors such as interface pressure control, soil sampling and testing, groundwater level control, and avoiding the influence of evaporation are fully considered, and the system integration is high.

[0017] 2. It can comprehensively analyze the vertical water-salt migration patterns of soil under the conditions of original soil and imported soil in saline-alkali areas, so as to adopt corresponding design plans and operation management methods in a targeted manner, which has important guiding significance for the selection of sponge city construction technology and facility operation and maintenance involving soil and plants in saline-alkali areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention.

[0019] Figure 2 It is an enlarged top view of the air vent in the present invention.

[0020] Figure 3 It is a schematic diagram of a structure in which only saline-alkali soil is filled in an inner tube.

[0021] Figure 4 It is a schematic diagram of a structure in which saline-alkali soil is filled in an inner tube and plants are planted.

[0022] Figure 5 It is a schematic diagram of a structure in which only planting soil is filled in an inner tube.

[0023] Figure 6 It is a schematic diagram of a structure in which an inner tube is filled with planting soil and a plant is planted. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific embodiments.

[0025] The present invention is a complete set of systems for studying and testing the water and salt migration law in the soil of coastal areas. A base 13 is fixed on the foot. The height of the base 13 from the ground is about 150 mm. An outer pipe 1 and an inner pipe 2 are fixed on the upper surface of the base 13. The outer pipe 1 is a groundwater simulation pipe, and the inner pipe 2 is a soil pipe. The diameter of the base is larger than the diameter of the outer pipe 1. The inner pipe 2 is located inside the outer pipe 1. An inner pipe vent valve 11 is provided on the base 13 within the range corresponding to the inner pipe 2. An outer tube vent valve 10 is provided on the base 13 between the outer tubes 1, and a water permeable hole 8 is opened on the inner tube 2 near the base 13. The water permeable hole 8 makes the outer tube 1 communicate with the inner tube 2, and the permeable geotextile is used to prevent soil from entering the outer tube 1 through the water permeable hole 8. An outer tube top plate 14 is fixed to the upper end of the outer tube 1, and the connection between the outer tube top plate 14 and the inner tube 2 and the base 13 and the inner tube 2 are all sealed. An air pressure balance pipe 5 is fixed on the outer tube top plate 14, and the inner tube 2 above the outer tube top plate 14 is sealed. An air guide hole 15 is provided on the outer tube 1, and the other end of the air pressure balance pipe 5 is connected to the air guide hole 15 to ensure that the outer tube 1 is ventilated, which can more realistically simulate the contact between the water and the soil interface. A soil sampling hole 9 is provided on the inner tube 2 above the outer tube top plate 14, and a liquid level controller 3 is fixed on the outer tube top plate 14. A liquid tank 7 is provided on one side of the outer tube 1, and a water inlet pipe 16 is fixed on the top cover plate of the liquid tank 7. A liquid adding pipe 4 is fixed on the outer tube top plate 14, and the water outlet of the liquid adding pipe 4 is The end extends into the outer tube 1, the water inlet end of the water inlet pipe 16 extends into the liquid tank 7, the water outlet end of the peristaltic pump 6 is connected to the water inlet end of the liquid adding pipe 4, the water inlet end of the peristaltic pump 6 is connected to the water outlet end of the water inlet pipe 16, the liquid level controller 3 is connected to the peristaltic pump 6, and a vent hole 12 is provided on the top cover plate of the liquid tank 7. The liquid level controller 3 is connected to the peristaltic pump 6 circuit, and the liquid adding pipe 4 is connected to the water circuit of the peristaltic pump 6. The liquid level controller 3 senses the liquid level change through the float to control the start and stop of the peristaltic pump 6.

[0026] The diameter of the outer tube 1 is 400-600 mm, and the height of the outer tube 1 is 300-500 mm.

[0027] The diameter of the inner tube 2 is 150-250 mm, and the height of the inner tube 2 is 1200-1800 mm.

[0028] An elastic sealing flap is fixed on the inner wall of the air vent 12 to prevent the saline solution in the liquid box 7 from evaporating and losing.

[0029] The diameter of the base 13 is 450-650 mm.

[0030] The liquid level controller 3 is a float type, and the floating range of the float is 2~38cm, so the groundwater level setting range is 2~38cm. The liquid level controller 3 controls the start and stop of the peristaltic pump 6, and the peristaltic pump 6 uses a 10mm silicone water inlet pipe, the water inlet end of the silicone water inlet pipe is connected to the 10mm liquid collection hole on the liquid box 7, and the water outlet end of the peristaltic pump 6 is connected to the liquid adding pipe 4.

[0031] The height of the water-permeable hole 8 from the bottom of the inner tube 2 is 8-12 mm, the diameter of the water-permeable hole 8 is 7-9 mm, and the number of the water-permeable holes 8 is 8-12.

[0032] The distance between the center of the air guide hole 15 and the outer tube top plate 14 is 8-12 mm, and the diameter of the air guide hole 15 is 8-12 mm.

[0033] The diameter of the soil sampling holes 9 is 8~12mm. The soil sampling holes 9 are arranged at two points along the circumferential diameter of the inner tube 2, two in a group, and the adjacent groups are vertically spaced 40~60mm apart. The soil sampling holes 9 are generally distributed in a cross shape along the circumference of the inner tube 2. The distance between the bottom group of sampling holes 9 and the outer tube top plate 14 is 40~60mm. A total of 18~22 groups of soil sampling holes 9 are arranged.

[0034] When studying and testing the law of water and salt migration in coastal soil, a total of 4 sets of the system of the present invention were used. Four groups of control tests were set in the inner tube 2, namely, saline-alkali soil 100, saline-alkali soil planted plants, planted soil 200, and planted soil planted plants. Soil was taken from sampling holes 9 at different heights of the inner tube 2 to compare and analyze the changes in water and salt in the soil of each control group. The soil particle size and compaction degree in the control group must be guaranteed to be consistent, the plant planting depth is 100mm, and the plant height and number of plants must be the same. The method for determining soil moisture is the weight method, and the method for determining soil salt is the conductivity method of quantitative soil air-dried samples made into aqueous solution and fully dissolved.

[0035] Taking the research and test of soil water and salt migration law in the Binhai Sino-Singapore Tianjin Eco-city area as an example, four sets of inner tubes 2 of this system were used to set up saline-alkali soil 100 (original soil of the eco-city), saline-alkali soil planted iris, planting soil 200 (greening planting soil), and planting soil planted iris. Four groups of control tests were set up in the inner tube 2 of 4 sets of this system. The initial soil particle size was 0.01~0.05mm, and the soil column filling operation method was consistent. The initial conductivity of saline-alkali soil 100 was 0.33mS / cm, and the initial conductivity of planting soil 200 was 0.04mS / cm. The planting depth of iris was 100mm, the initial plant height was 200mm, and the number of plants in each group was 5. The salt water concentration simulated the groundwater in the area was 15000mg / L, and the groundwater level was set at 200mm and 350mm (13 from the base) in the two stages.

[0036] After 3 months of testing, both saline-alkali soil 100 and planting soil 200 showed a trend that the closer to the groundwater level, the higher the water content; the water content of planting soil 200 increased faster than that of saline-alkali soil 100, and the water content was higher; the time for the water content of planting soil 200 to reach stability at 800mm from the groundwater level was 20 days, while that of saline-alkali soil 100 was 30 days. The closer the saline-alkali soil 100 was to the groundwater level, the faster the conductivity increased, and the conductivity in the middle of the soil column (350-700mm from the groundwater level) was high, and low at both ends; the closer the planting soil 200 was to the groundwater level, the faster the conductivity increased, and the higher the conductivity; the time for the conductivity of planting soil 200 to reach stability at 800mm from the groundwater level was 40 days, while that of saline-alkali soil 100 was 75 days. At the same distance from the groundwater level, the soil moisture and conductivity of the control group planted with irises increased faster than those of the group without plants, especially at 700-800mm from the groundwater level. The effect of irises in the planting soil 200 group on soil moisture and conductivity was greater than that of irises in the saline-alkali soil 100 group. As the groundwater level increased, the stable layers of soil moisture and conductivity moved upward accordingly. In general, the soil moisture and conductivity of each control group did not change much above 850mm from the groundwater level. During the experiment, the system operated stably, and the research on different control groups showed that there were significant differences in the water and salt migration laws between saline-alkali soil and planting soil. At the same time, plants also had a certain impact on the migration of water and salt in the soil. The height of the soil layer affected by groundwater in this area was explored, which has significant guiding significance for the technical selection, parameter design and operation and maintenance management of sponge city construction in Sino-Singapore Tianjin Eco-City and even similar coastal areas.

Claims

1. A complete system for studying and testing the water and salt migration law in coastal soil, characterized by: A base (13) is fixed on the foot, an outer tube (1) and an inner tube (2) are fixed on the upper surface of the base (13), the diameter of the base is larger than the diameter of the outer tube (1), the inner tube (2) is located inside the outer tube (1), an inner tube vent valve (11) is provided on the base (13) within the range of the inner tube (2), an outer tube vent valve (10) is provided on the base (13) between the inner tube (2) and the outer tube (1), a water permeable hole (8) is provided on the inner tube (2) near the base (13), an outer tube top plate (14) is fixed on the upper end of the outer tube (1), the connection between the outer tube top plate (14) and the inner tube (2) and the base (13) and the inner tube (2) are sealed, an air pressure balance pipe (5) is fixed on the outer tube top plate (14), and an air guide hole (15) is provided on the inner tube (2) above the outer tube top plate (14). ), the other end of the air pressure balance pipe (5) is connected to the air guide hole (15), a soil sampling hole (9) is opened on the inner tube (2) above the outer tube top plate (14), a liquid level controller (3) is fixed on the outer tube top plate (14), a liquid box (7) is provided on one side of the outer tube (1), a water inlet pipe (16) is fixed on the top cover plate of the liquid box (7), a liquid adding pipe (4) is fixed on the outer tube top plate (14), the water outlet end of the liquid adding pipe (4) extends into the outer tube (1), the water inlet end of the water inlet pipe (16) extends into the liquid box (7), the water outlet end of the peristaltic pump (6) is connected to the water inlet end of the liquid adding pipe (4), the water inlet end of the peristaltic pump (6) is connected to the water outlet end of the water inlet pipe (16), the liquid level controller (3) is connected to the peristaltic pump (6), and a vent hole (12) is provided on the top cover plate of the liquid box (7); The diameter of the outer tube (1) is 400-600 mm, and the height of the outer tube (1) is 300-500 mm; The diameter of the inner tube (2) is 150-250 mm, and the height of the inner tube (2) is 1200-1800 mm; An elastic sealing flap is fixed on the inner wall of the air vent (12); The diameter of the base (13) is 450-650 mm; The liquid level controller (3) is of a float type, and the floating range of the float is 2 to 38 cm; The height of the water-permeable hole (8) from the bottom end of the inner tube (2) is 8 to 12 mm, the diameter of the water-permeable hole (8) is 7 to 9 mm, and the number of the water-permeable holes (8) is 8 to 12; The distance between the center of the air guide hole (15) and the outer tube top plate (14) is 8 to 12 mm, and the diameter of the air guide hole (15) is 8 to 12 mm; The diameter of the soil sampling holes (9) is 8 to 12 mm. The soil sampling holes (9) are arranged at two points along the circumference of the inner tube (2), two of which form a group, and the intervals between two adjacent groups are 40 to 60 mm. The soil sampling holes (9) are generally distributed in a cross shape along the circumference of the inner tube (2). The distance between the bottom group of soil sampling holes (9) and the outer tube top plate (14) is 40 to 60 mm. A total of 18 to 22 groups of soil sampling holes (9) are provided.

Images