A device suitable for soil water infiltration and evaporation cycle test

Abstract

The application relates to the field of soil monitoring and discloses a device suitable for soil water absorption and evaporation cycle test, which comprises a sample testing mechanism, the sample testing mechanism comprises a sealed cover box, the bottom of the sealed cover box is provided with a cement layer, the cement layer is internally provided with a buried heating component, the cement layer is provided with a weighing table, the weighing table is provided with an acrylic bottom plate for loading a sample and water, the top of the acrylic bottom plate is provided with a surrounding frame, the acrylic bottom plate is provided with two concave shallow clamping grooves, the surrounding frame is provided with a water supply Ma's bottle on one side and is connected with a valve three. A bionic constraint system is constructed through an adjustable air pressure elastic film + an angle-adjustable frosted water-permeable partition plate, constraint stress in real-time feedback of a pressure sensor is dynamically associated with crack expansion captured by a high-definition camera, and a coupling rule of constraint strength-crack morphology-seepage velocity is quantitatively revealed for the first time.

Description

Technical Field

[0001] This invention relates to the field of soil monitoring technology, specifically to a test device for soil moisture absorption and evaporation cycles. Background Technology

[0002] Soil cracking is a key scientific challenge in ecological geotechnical engineering and water environment fields. Especially in arid environments, soil shrinkage and cracking not only lead to rapid soil moisture loss, hindered vegetation growth, and shallow soil block slippage and instability on slopes, but also accelerate the migration and diffusion of pollutants through crack channels. When rainwater or surface runoff carries pollutants (such as agricultural non-point source pollutants and industrial leachate pollutants) into the soil, the preferential flow paths formed by cracks significantly increase the infiltration efficiency of pollutants into deeper soil and groundwater, posing a potential threat to water environment safety. Therefore, studying the mechanisms of water evaporation and infiltration processes before and after soil cracking is not only an important theoretical basis for revealing soil hydrological processes, but also a key prerequisite for analyzing the migration and transformation patterns of pollutants in the soil-water system.

[0003] Current research and experimental design on soil column tests mostly focus on vertical evapotranspiration. Because the column opening is typically circular and small, it is subject to strong boundary effects, resulting in poor cracking performance after drying. Existing devices cannot adequately simulate the evapotranspiration process after layered soil drying and cracking, nor can they accurately capture the impact mechanism of crack channels on pollutant migration. Furthermore, there is a lack of research on the correlation between lateral infiltration and pollutant transport in the horizontal direction. Although a few scholars have attempted to study horizontal seepage processes by placing soil columns horizontally, this method cannot capture the cracking and damage effects of soil during the drying stage, nor can it simulate the migration path of pollutants under the coupling effect of cracking and moisture. In addition, the temperature field generated by the heat source (incandescent lamp) used in traditional methods to simulate a dry environment is spatially uneven and differs significantly from the actual environment. Moreover, the scale of soil wetting front movement, measured manually, suffers from visual errors. These problems all limit in-depth research on the synergistic migration mechanism of soil moisture and pollutants. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a test device suitable for soil moisture absorption and evaporation cycles. It solves the problems that current soil column test studies are mostly limited to the vertical evaporation process, resulting in strong boundary effects, poor simulation of cracking, lack of research on horizontal seepage, uneven thermal field, and large errors in manual observation.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a test device for soil moisture infiltration and evaporation cycle, comprising a liquid-push water supply mechanism, a sample testing mechanism, a wetting peak scale testing mechanism, and a numerical control output mechanism;

[0006] The hydraulic water supply mechanism includes a water supply Marshall bottle, which has an opening at the bottom and is connected to a valve. A scissor lift platform is provided at the bottom of the water supply Marshall bottle, and a long screw rod is provided in the middle of the scissor lift platform support. The water supply Marshall bottle is connected to the sample testing mechanism through a rubber hose.

[0007] The sample testing mechanism includes a sealed shielded box with a cement layer at the bottom. An underground heating component is installed inside the cement layer. A weighing platform is installed on the cement layer, and an acrylic base plate supporting the sample and water is installed on the weighing platform. A protective frame is installed on top of the acrylic base plate, and the acrylic base plate has two shallow concave grooves. An opening is made on the side of the protective frame near the water supply bottle, and a valve three is connected to it. The valve three is connected to a valve two via a rubber hose. Opposite adhesive steel teeth are installed on the top of the protective frame. The shallow concave grooves of the protective frame are respectively embedded with a first and a second frosted permeable baffle. Furthermore, the first and second frosted permeable baffles move within the enclosure frame along concave shallow grooves. Micron-level grooves are etched on the surfaces of the first and second frosted permeable baffles to simulate soil particle interfaces. Elastic constraint membranes distributed on both sides are added to the outer side, and the membranes are filled with airbags with adjustable air pressure and contain miniature pressure sensor elements. A predetermined water level gauge is provided on the side wall between the enclosure frame and the first frosted permeable baffle. A bearing cavity for bearing the test soil is provided between the first and second frosted permeable baffles. A high-definition camera is installed directly above the top of the sealed shield box, and a temperature sensor is installed at the bottom of the inner wall of the sealed shield box.

[0008] The wet front scale testing mechanism includes a stainless steel guide rail, on which a laser instrument is provided that can slide linearly along the length direction, and the laser instrument can emit a vertical laser beam.

[0009] The numerical control output mechanism includes a control terminal for acquiring images and data. The control terminal is connected to a weighing platform, a high-definition camera, and a temperature sensor, and is also connected to a temperature controller.

[0010] Preferably, the water supply bottle has a hollow tube connected to the atmosphere fixed inside, and the top of the water supply bottle has an opening and is connected to a valve.

[0011] Preferably, the central part of the sealed shield box has a glass-shaped light-transmitting structure.

[0012] Preferably, the buried heating component includes an electric heating wire, a three-dimensional heat-conducting pipe network, and an infrared heating plate on top of it, with a temperature-controlled liquid circulating in the pipe network.

[0013] Preferably, the acrylic base plate is provided with movable feet at the bottom, and a horizontal calibration bubble gauge is provided at the corner of the acrylic base plate.

[0014] Preferably, the enclosure frame has an opening on the side away from the valve and is provided with two rows of fine-tuning screws, with two screws in the lower row at three equal points and one screw in the upper row at one equal point.

[0015] Preferably, the sealed enclosure is equipped with an exhaust fan and a lighting lamp on its side.

[0016] Preferably, the stainless steel guide rail is level with the weighing platform surface and is placed parallel to the side wall of the enclosure frame.

[0017] Preferably, the vertical laser beam is perpendicular to the adhesive steel teeth.

[0018] Preferably, the other end of the temperature controller is connected to an underground heating component for regulating the temperature of the experimental environment.

[0019] This invention provides a device suitable for testing soil moisture infiltration and evaporation cycles. It has the following beneficial effects:

[0020] 1. This invention possesses a composite thermal field precision simulation technology: the three-dimensional gradient heating system (layered layout of electric heating wires + heat conduction pipe network + infrared heating plate) achieves independent control of internal soil heat conduction and surface radiation heat through temperature controller and computer feedback adjustment, which can accurately simulate the composite thermal field effect of "solar radiation + ground temperature gradient" in the natural environment and improve the uniformity of the thermal field.

[0021] 2. This invention features dynamic boundary constraint control technology: an adjustable air pressure elastic membrane and an adjustable tilt angle frosted permeable baffle form a biomimetic constraint system. The constraint stress fed back in real time by the pressure sensor and the crack propagation captured by the high-definition camera form a dynamic correlation, revealing for the first time the coupling law of constraint strength-crack morphology-seepage velocity in a quantitative manner.

[0022] 3. This invention features a modular and scalable design: the quick-change structure of the frosted permeable baffle shortens sample replacement time, and the adjustable sample box is adaptable to different soil textures, from clay to sand. Engineering verification shows that this design expands the testing capabilities of a single device into multiple combinations.

[0023] 4. This invention features water and heat transport visualization technology: An acrylic base plate combined with a three-dimensional lighting system and high-definition cameras enables full-process visualization observation of the dynamic propagation of wetting fronts, water redistribution, and crack development. The experiment successfully captured the phenomenon of "preferential flow passing through historical crack paths," providing direct evidence for the study of soil memory effects. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the main structure of the experimental device of the present invention. Figure 1 ;

[0025] Figure 2 This is a schematic diagram of the main structure of the experimental device of the present invention. Figure 2 ;

[0026] Figure 3 This is a schematic diagram of the main structure of the experimental device of the present invention. Figure 3 ;

[0027] Figure 4 This is a schematic diagram of the sample testing mechanism of the present invention;

[0028] Figure 5 This is a schematic diagram of the internal mechanism for sample testing according to the present invention. Figure 1 ;

[0029] Figure 6 This is a schematic diagram of the internal mechanism for sample testing according to the present invention. Figure 2 ;

[0030] Figure 7 This is a schematic diagram of the internal mechanism for sample testing according to the present invention. Figure 3 ;

[0031] Figure 8 These are schematic diagrams of the first and second frosted permeable baffles of the present invention.

[0032] Figure 9 This is a photograph of the first infiltration process of the test soil in this invention.

[0033] Figure 10 This is a photograph of the experimental soil after the first infiltration of the soil used in this invention.

[0034] Figure 11 This is a photograph of the first evaporation process of the experimental soil in this invention.

[0035] Figure 12 This is a photograph of the second infiltration process of the test soil in this invention.

[0036] Figure 13 This is a schematic diagram of the wetting front movement process curve during the two absorption processes of the present invention.

[0037] The components include: 1. Hydraulic water supply mechanism; 2. Sample testing mechanism; 3. Wetting peak scale testing mechanism; 4. CNC output mechanism; 11. Water supply bottle; 12. Hollow pipe; 13. Valve 1; 14. Valve 2; 15. Rubber hose; 16. Scissor lift platform; 17. Long screw rod; 21. Sealed shield box; 22. Cement layer; 23. Underground heating component; 24. Weighing platform; 25. Acrylic base plate; 26. Movable feet; 27. Leveling bubble gauge. 28. Enclosure frame; 29. ​​Valve III; 210. Fine-tuning screw rod; 211. Adhesive steel toothed plate; 212. Frosted permeable baffle I; 213. Frosted permeable baffle II; 214. Load-bearing cavity; 215. Exhaust fan; 216. Lighting lamp; 217. High-definition camera; 218. Temperature sensor; 219. Preset water level gauge; 31. Stainless steel guide rail; 32. Laser instrument; 33. Vertical laser beam; 41. Control terminal; 42. Temperature controller. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Please see the appendix Figure 1 -Appendix Figure 3This invention provides a soil moisture infiltration and evaporation cycle testing device, including a liquid-push water supply mechanism 1, a sample testing mechanism 2, a wetting front scale testing mechanism 3, and a numerical control output mechanism 4. The liquid-push water supply mechanism 1 includes a water supply Marshall bottle 11, with an opening at the bottom and a valve 14 connected to it. A scissor lift platform 16 is provided at the bottom of the water supply Marshall bottle 11, and a long screw rod 17 is provided in the middle of the support of the scissor lift platform 16. The water supply Marshall bottle 11 is connected to the sample testing mechanism 2 through a rubber hose 15. A hollow tube 12 communicating with the atmosphere is fixed inside the water supply Marshall bottle 11. A valve 13 is connected to the top of the water supply Marshall bottle 11. Sufficient clean water is filled into the water supply Marshall bottle 11 and placed stably on the scissor lift platform 16. The valve 13 is opened and the water flows through the scissor lift platform 16. Air is blown into the bottle through the hollow tube 12 to remove air bubbles in the water. After the liquid level in the water supply Margaret bottle 11 is stable, valve 13 is closed. The long screw rod 17 is adjusted to move the lifting platform 6 up and down so that the bottom of the hollow tube 12 is at the same level as the sample. During the drying test, the front and rear lights 216 are turned on first, and the high-definition camera 217, laser instrument 32 and control terminal 41 are turned on simultaneously. After setting the acquisition frequency, various data are successfully collected. Then, valve 214 is opened to allow water in the water supply Margaret bottle to enter the water collection tank through the rubber hose and reach the preset water level gauge height 219. At this time, the liquid level scale in the water supply Margaret bottle 11 and the wettability scale indicated by the laser instrument 32 are recorded. Then, the liquid level scale in the water supply Margaret bottle 11 is recorded at fixed time intervals ts.

[0040] Please see the appendix Figure 1 -Appendix Figure 7The sample testing mechanism 2 includes a sealed shielded box 21. The bottom of the sealed shielded box 21 has a cement layer 22. Inside the cement layer 22 is an underground heating component 23. The underground heating component 23 includes electric heating wires, a three-dimensional heat-conducting pipe network, and an infrared heating plate on top. A temperature-controlled liquid, such as an ethylene glycol solution, circulates in the pipe network. The infrared heating plate on top has a wavelength of 2-15 μm. Adjustable, a weighing platform 24 is installed on the cement layer 22, and an acrylic base plate 25 is installed on the weighing platform 24 to support the sample and water. A protective frame 28 is installed on the top of the acrylic base plate 25. The acrylic base plate 25 has two concave shallow grooves. The protective frame 28 has an opening on the side near the water supply bottle 11 and is connected to valve 3 29. Valve 3 29 is connected to valve 2 14 through rubber hose 15. The top of the protective frame 28 is provided with front and rear opposing adhesive steel teeth 211. The concave shallow grooves of the protective frame 28 are respectively embedded with frosted permeable baffle 1 212 and frosted permeable baffle 212. 13. Furthermore, the first and second permeable frosted baffles (212 and 213) move within the enclosure frame 28 along concave shallow grooves. Micron-level grooves are etched on the surfaces of the first and second permeable baffles (212 and 213) to simulate the soil particle interface, mimicking the rough surface of real soil particles, enhancing the mechanical interlocking between the baffles and the soil, and making experimental or engineering conditions closer to the physical interface characteristics of natural soil. The groove structure can guide the directional alignment of soil particles, reduce interface slippage, and more realistically reflect the shear behavior of soil under natural conditions. The first and second permeable baffles (212 and 213)... An elastic restraint membrane is added to the outer side of the 213 plate. The membrane is filled with an adjustable-pressure airbag. Pressure sensors provide real-time feedback on soil expansion / contraction stress. The restraint force of the elastic membrane is adjusted by inflating and deflating the airbag, flexibly adapting to soil expansion / contraction deformation caused by humidity, temperature, etc. This avoids stress concentration or interface delamination caused by rigid structures. The pressure sensors monitor changes in soil stress, providing data support for research or engineering control (such as determining the degree of soil consolidation and expansion potential). The flexible restraint membrane evenly distributes soil deformation stress, preventing localized crushing or cracking, making it particularly suitable for easily disturbed cohesive or expansive soils. For expansive soil, the air pressure is adjusted according to different soil types to balance the needs of "fixation" and "allowing natural deformation". A predetermined water level gauge 219 is set on the side wall between the enclosure frame 28 and the first permeable partition 212. A bearing cavity 214 for bearing the test soil is set between the first permeable partition 212 and the second permeable partition 213. A high-definition camera 217 is set on the top of the sealed shield box 21. A temperature sensor 218 is set on the bottom of the inner wall of the sealed shield box 21. The middle of the sealed shield box 21 has a glass-shaped light-transmitting structure. Movable feet 26 are set on the bottom of the acrylic base plate 25. A level calibration bubble gauge 27 is set at the corner of the acrylic base plate 25. An opening is set on the side of the enclosure frame 28 away from the third valve 29 and two rows of fine adjustment screws 210 are set. Two screws are set at the third division of the lower row of fine adjustment screws 210, and one screw is set at the middle division of the upper row of fine adjustment screws 210.The sealed enclosure 21 is equipped with an exhaust fan 215 and a lighting lamp 216 on its side. The outer shell of this soil moisture absorption and evaporation cycle test device is a sealed enclosure 21, and the interior contains a buried heating component 23, a weighing platform 24, an acrylic base plate 25 for supporting the sample and water, and a high-definition camera 217. The buried heating component 23 is embedded in the cement layer at the bottom of the sealed enclosure 21. It includes electric heating wires, a three-dimensional heat conduction pipe network, and an infrared heating plate on top. The electric heating wires can be arranged in 2-4 layers, with each layer of wires coiled in an S-shape and fixed in the cement. The spacing between each layer of wires should be greater than 2cm, and at least 2cm of cement should be reserved at the top and bottom of the electric heating wires. A temperature-controlled liquid, such as ethylene glycol solution, circulates in the three-dimensional heat conduction pipe network, which works in conjunction with the infrared heating plate on top with a wavelength of 2-15 nm. The temperature is adjustable to μm. The operating temperature of the underfloor heating system is regulated by a temperature controller 42, which is connected to a computer system. When manufacturing the underfloor heating system, the bottom dimensions of the sealed enclosure 21 must be considered to ensure proper embedding and closure. A temperature sensor 218 is installed 10-20cm above the top surface of the cement layer of the underfloor heating system to monitor the ambient temperature. This temperature sensor 218 is fixed to the side of the sealed enclosure 21 and connected to the computer system. The temperature sensor value tc is compared with the expected value tr input to the computer. If there is a large difference between tc and tr, the computer issues a command to automatically control the temperature controller 42, adjusting the operating power until tc = tr ± 5%, achieving a soil internal temperature gradient of 0.5℃ / °C. Independent control of m and surface radiation intensity simulates the composite thermal field of "soil-atmosphere interface radiation + ground temperature conduction" in the natural environment. After the cement reaches its curing strength, a weighing platform 24 is placed on the cement layer 22. After placement, the weighing platform 24 is adjusted to a horizontal position using its built-in spiral feet. The weight storage module of the weighing platform is connected to a computer, which can record and store the weight in real time. A sample box structure consisting of an acrylic base plate 25 and an enclosure frame 28 is placed on the horizontally adjusted weighing platform 24. The four movable feet at the bottom of the sample box are adjusted, and the level calibration bubble ruler at the acrylic base plate 25 is observed to be centered, ensuring that the sample box structure is horizontal. A frosted permeable partition 212 is placed in the slot at the bottom of the sample box. And a permeable frosted concrete baffle plate 213, while an elastic constraint membrane is added to the outside of both permeable frosted concrete baffle plate 212 and permeable frosted concrete baffle plate 213. The membrane is filled with an air bladder with adjustable air pressure. The soil expansion / contraction stress is fed back in real time through pressure sensors to simulate the constraint effect of the surrounding rock mass on the expansion of cracks in the natural environment, such as the slope soil being restricted by the rock mass on both sides. The coupling process of stress-cracking-seepage is monitored simultaneously, and a new law is found that "the higher the boundary constraint strength, the smaller the crack opening, but the faster the lateral seepage". The size of the permeable frosted concrete baffle plate can be adjusted according to the size of the experimental sample. The width of permeable frosted concrete baffle plate 212 is slightly smaller than the width of the slot by 0.5 mm to facilitate easy removal and insertion. The width of permeable frosted concrete baffle plate 213 is 1 cm smaller than the width of the slot.The second permeable frosted partition 213 is fixed by the fine-adjustment screw 210. After the test, the fine-adjustment screw 210 is removed to facilitate the removal of the second permeable frosted partition 213, thus achieving the purpose of smoothly disassembling the sample. The tilt angle of the second permeable frosted partition 213 can be adjusted from 0° to 45° by rotating the screw. After the first permeable frosted partition 212 and the second permeable frosted partition 213 are fixed, the sample to be tested is placed in the bearing cavity 214 between them. The sample thickness is set in advance, and the sample height is marked at the corresponding position in the sample box. The prepared soil is weighed and placed in the middle of the sample box. The soil is gently compacted with a small wooden mallet according to the maximum dry density standard. After the sample is placed at the preset position and the test is completed, open valve 29, adjust the four movable feet 26 again for secondary leveling, and fix the sealed cover box 21. After the infiltration test is completed, turn on the underground heating component 23, set the expected test temperature, turn on the exhaust fan 215 to help remove moisture from the cover box, turn on the high-definition camera 217 to capture images during the drying process, and control the control terminal 41 to simultaneously control the cover box temperature and record the weight. When the test sample weight change rate is less than 1g / hour, the soil drying is considered complete, and the test is stopped. The next cycle of infiltration test of the dried soil is then conducted, and the above drying test process is repeated.

[0041] Please see the appendix Figure 1 -Appendix Figure 7 The wetting front calibration test mechanism 3 includes a stainless steel guide rail 31. The stainless steel guide rail 31 is equipped with a laser instrument 32 that can slide linearly along its length. The laser instrument 32 can emit a vertical laser beam 33. The height of the stainless steel guide rail 31 is level with the weighing platform 24, and its placement direction is parallel to the side wall of the enclosure frame 28. The vertical laser beam 33 is perpendicular to the adhesive steel teeth 211. The laser instrument 32 slides on the stainless steel guide rail 31 to record the wetting front calibration until the wetting front reaches the position of the second permeable sandblasting baffle 213 and water seeps out. The sample absorption and permeation stage is considered to be completed. Then, the valve 214 is closed to stop the test, and the high-definition camera 217 and the laser instrument 32 are turned off to stop recording the evaporation experiment process.

[0042] Please see the appendix Figure 1 -Appendix Figure 4 The numerical control output mechanism 4 includes a control terminal 41 for acquiring images and data. The control terminal 41 is connected to the weighing platform 24, the high-definition camera 217 and the temperature sensor 218. The control terminal 41 is connected to the temperature controller 42. The other end of the temperature controller 42 is connected to the underground heating component 23 for regulating the temperature of the experimental environment.

[0043] Working principle: See attached document Figure 1-13The soil moisture absorption and evaporation cycle test device has a sealed enclosure 21, inside which are a buried heating component 23, a weighing platform 24, an acrylic base plate 25 to support the sample and water, and a high-definition camera 217. The buried heating component 23 is embedded in the cement layer at the bottom of the sealed enclosure 21. It includes electric heating wires, a three-dimensional heat conduction pipe network, and an infrared heating plate on top. The electric heating wires can be arranged in 2-4 layers, with each layer coiled in an S-shape and fixed in the cement. The spacing between each layer should be greater than 2 cm, and at least 2 cm of cement should be reserved at the top and bottom of the electric heating wires. A temperature-controlled liquid, such as ethylene glycol solution, circulates in the three-dimensional heat conduction pipe network. Combined with the adjustable wavelength of the infrared heating plate at the top (2-15 μm), the electric heating works. The temperature is regulated by a temperature controller 42, which is connected to a computer system. When constructing the underfloor heating system, the bottom dimensions of the sealed enclosure 21 must be considered to ensure a secure and closed fit. A temperature sensor 218 is installed 10-20 cm above the top surface of the cement layer of the underfloor heating system to monitor the ambient temperature. This temperature sensor 218 is fixed to the side of the sealed enclosure 21 and connected to the computer system. The temperature sensor value tc is compared with the expected value tr input to the computer. If there is a significant difference between tc and tr, the computer issues a command to automatically control the temperature controller 42, adjusting its power until tc = tr ± 5%, achieving a soil internal temperature gradient of 0. Independent control of 0.5℃ / cm and surface radiation intensity simulates the composite thermal field of "soil-atmosphere interface radiation + ground temperature conduction" in the natural environment. After the cement reaches its curing strength, a weighing platform 24 is placed on the cement layer 22. After placement, the weighing platform 24 is adjusted to a horizontal position using its built-in spiral feet. The weight storage module of the weighing platform is connected to a computer, which can record and store the weight in real time. A sample box structure consisting of an acrylic base plate 25 and a retaining frame 28 is placed on the leveled weighing platform 24. The four movable feet at the bottom of the sample box are adjusted, and the level calibration bubble ruler at the acrylic base plate 25 is observed to be centered, ensuring that the sample box structure is level. In the bottom slot of the sample box, a permeable frosted baffle 1 (212) and a permeable frosted ...The width of the permeable sandblasting baffle 213 is 1 cm less than the width of the slot, and it is fixed by a fine-adjustment screw rod 210. After the test, the fine-adjustment screw rod 210 is removed to facilitate the removal of the permeable sandblasting baffle 213, thus achieving the purpose of smoothly disassembling the sample. The inclination angle of the permeable sandblasting baffle 213 can be adjusted from 0° to 45° by rotating the screw. After the permeable sandblasting baffle 1 212 and the permeable sandblasting baffle 213 are fixed, the sample to be tested is placed in the bearing cavity 214 between them. The sample thickness is set in advance, and the sample height is marked at the corresponding position in the sample box. The prepared soil is weighed. Place the soil in the center of the sample box and gently compact it with a small wooden mallet according to the maximum dry density standard until it reaches the preset position. After the sample is completed, open valve 29 and adjust the four movable feet 26 again for secondary leveling. Fix the sealed shield box 21, fill the water supply bottle 11 with sufficient clean water, and place it stably on the scissor lift platform 16. Open valve 13 and blow air into the bottle through the hollow tube 12 to remove air bubbles in the water. After the liquid level in the water supply bottle 11 is stable, close valve 13. Adjust the long screw rod 17 to move the lift platform 6 up and down so that the bottom of the hollow tube 12 is at the same level as the sample height. During the drying test, first open... Turn on the front and rear side lights 216, and simultaneously turn on the high-definition camera 217, laser instrument 32, and control terminal 41. After setting the acquisition frequency, start collecting various data smoothly. Then, open valve 14 to allow water in the water supply bottle to enter the water collection tank through the rubber hose and reach the preset water level gauge height 219. At this time, record the liquid level scale in the water supply bottle 11 and the wetted front scale indicated by the laser instrument 32. Then, record the liquid level scale in the water supply bottle 11 at fixed time intervals ts. Slide the laser instrument 32 on the stainless steel guide rail 31 to record the wetted front scale until the wetted front reaches the position of the frosted permeable baffle 213 and clear water is detected. Once leaching occurs, the sample's absorption phase is considered complete. Valve 14 is then closed to stop the test. The high-definition camera 217 and laser instrument 32 are turned off to stop recording the evaporation process. After the absorption test is complete, the underground heating component 23 is switched on, the expected test temperature is set, and the exhaust fan 215 is turned on to help remove moisture from the shielded box. The high-definition camera 217 is turned on to capture images of the drying process. The control terminal 41 simultaneously controls the shielded box temperature and records the weight. When the sample weight change rate is less than 1 g / hour, the soil drying is considered complete, and the test is stopped. The next cycle of the dried soil absorption test is then conducted, repeating the above drying test process.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A test device for soil moisture infiltration and evaporation cycles, comprising a liquid-push water supply mechanism (1), a sample testing mechanism (2), a wetting peak calibration testing mechanism (3), and a numerical control output mechanism (4), characterized in that: The liquid-push water supply mechanism (1) includes a water supply Marshall bottle (11), the bottom of which is opened and connected to a valve (14), a scissor lift platform (16) is provided at the bottom of the water supply Marshall bottle (11), a long screw rod (17) is provided in the middle of the support of the scissor lift platform (16), and the water supply Marshall bottle (11) is connected to the sample testing mechanism (2) through a rubber hose (15). The sample testing mechanism (2) includes a sealed shielded box (21), with a cement layer (22) at the bottom of the sealed shielded box (21). An underground heating component (23) is installed inside the cement layer (22). A weighing platform (24) is installed on the cement layer (22). An acrylic base plate (25) supporting the sample and water is installed on the weighing platform (24). A protective frame (28) is installed on the top of the acrylic base plate (25). The acrylic base plate (25) has two concave shallow grooves. The protective frame (28) has an opening near the water supply bottle (11) and is connected to valve three (29). Valve three (29) is connected to valve two (14) via a rubber hose (15). The top of the protective frame (28) has front and rear opposing adhesive steel teeth (211). The concave shallow grooves of the protective frame (28) are respectively embedded in a frosted permeable baffle plate (212) and... A second permeable frosted partition (213) is provided, and the first permeable frosted partition (212) and the second permeable frosted partition (213) move within the enclosure frame (28) along a concave shallow groove. The surfaces of the first permeable frosted partition (212) and the second permeable frosted partition (213) are etched with micron-level grooves to simulate the soil particle interface. An elastic constraint membrane is added to the outer side with two edges distributed on both sides. The membrane is filled with an air bladder with adjustable air pressure and has a micro pressure sensor element inside. A predetermined water level gauge (219) is provided on the side wall between the enclosure frame (28) and the first permeable frosted partition (212). A bearing cavity (214) for bearing the test soil is provided between the first permeable frosted partition (212) and the second permeable frosted partition (213). A high-definition camera (217) is provided directly above the top of the sealed shield box (21). A temperature sensor (218) is provided at the bottom of the inner wall of the sealed shield box (21). The wet front scale testing mechanism (3) includes a stainless steel guide rail (31), and the stainless steel guide rail (31) is equipped with a laser (32) that can slide linearly along the length direction. The laser (32) can emit a vertical laser beam (33). The numerical control output mechanism (4) includes a control terminal (41) for acquiring images and data. The control terminal (41) is connected to a weighing platform (24), a high-definition camera (217), and a temperature sensor (218). The control terminal (41) is connected to a temperature controller (42). The other end of the temperature controller (42) is connected to an underground heating component (23) for regulating the temperature of the experimental environment.

2. The experimental device for soil moisture infiltration and evaporation cycle according to claim 1, characterized in that, The water supply bottle (11) has a hollow tube (12) that is connected to the atmosphere inside, and the top of the water supply bottle (11) has an opening and is connected to a valve (13).

3. The experimental device for soil moisture infiltration and evaporation cycle according to claim 1, characterized in that, The sealed shield box (21) has a glass-shaped light-transmitting structure in the middle.

4. The experimental device for soil moisture infiltration and evaporation cycle testing according to claim 1, characterized in that, The underground heating component (23) includes an electric heating wire, a three-dimensional heat-conducting pipe network and an infrared heating plate on top of it, with temperature-controlled liquid circulating in the pipe network.

5. The experimental device for soil moisture infiltration and evaporation cycle according to claim 1, characterized in that, The acrylic base plate (25) is provided with movable feet (26) at the bottom, and a horizontal calibration bubble gauge (27) is provided at the corner of the acrylic base plate (25).

6. The experimental device for soil moisture infiltration and evaporation cycle according to claim 1, characterized in that, The enclosure frame (28) has an opening on the side away from the valve (29) and is provided with two rows of fine adjustment screws (210). The lower row of fine adjustment screws (210) has two screws at three equal divisions, and the upper row of fine adjustment screws (210) has one screw at one equal division.

7. The experimental device for soil moisture infiltration and evaporation cycle testing according to claim 1, characterized in that, The sealed enclosure (21) is equipped with an exhaust fan (215) and a lighting lamp (216) on its side.

8. The experimental device for soil moisture infiltration and evaporation cycle according to claim 1, characterized in that, The stainless steel guide rail (31) is level with the weighing platform (24) and is placed in a direction parallel to the side wall of the enclosure frame (28).

9. The experimental device for soil moisture infiltration and evaporation cycle according to claim 1, characterized in that, The vertical laser beam (33) is perpendicular to the adhesive steel teeth (211).

Images