A soil sampling device and method for soil testing

Abstract

This invention relates to the field of soil sampling technology, specifically to a soil sampling device for soil testing, comprising a Z-shaped plate, with two electric push rods fixedly connected to the upper end of the Z-shaped plate. The output ends of the two electric push rods are jointly fixedly connected to a sampling cylinder, and a conical cylinder is fixedly connected to the lower end of the sampling cylinder. A quick-freezing mechanism is provided inside the sampling cylinder, including an annular cooling groove at the upper end of the sampling cylinder, and multiple sliding rods are fixedly connected to the upper end of the sampling cylinder. This invention also relates to a soil sampling method for soil testing, comprising the following steps: S1, injecting anhydrous ethanol into the annular cooling groove, at which point the sealing ring is in the open state. This invention utilizes a low-temperature refrigerant mixture of anhydrous ethanol and dry ice, combined with a mixing mechanism for uniform heat transfer, to rapidly freeze and solidify soft soil with high moisture content, preventing soil rheology, collapse, and stratification, preserving the original physicochemical structure of the soil to the greatest extent possible, and facilitating subsequent extraction.

Description

Technical Field

[0001] This invention relates to the field of soil sampling technology, specifically to a soil sampling device and sampling method for soil testing. Background Technology

[0002] In the field of soil testing, soil sampling devices mostly use direct-push or rotary sampling tubes. These sampling tubes are effective for sampling soils with a high degree of consolidation, such as hard plastic clay and sand. However, they have obvious drawbacks when sampling soft soil layers such as soft soil with high water content.

[0003] Because the sampling tube is a downward-pressure sampling method, it is easy to cause compression and disturbance to the soft soil layer with high water content. Due to the low shear strength and high fluidity of the soft soil itself, it is easy to collapse, drop the sample, and undergo soil rheological deformation after the tube is pulled out. It is difficult to maintain the original pore structure and soil layering state. In addition, the soil layer is severely adhered to the tube wall, and secondary deformation or damage is easy to occur when sampling from inside the tube. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art by proposing a soil sampling device and sampling method for soil testing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A soil sampling device for soil testing includes a Z-shaped plate, with two electric push rods fixedly connected to the upper end of the Z-shaped plate, and a sampling cylinder fixedly connected to the output ends of the two electric push rods. A conical cylinder is fixedly connected to the lower end of the sampling cylinder.

[0007] The sampling cylinder is equipped with a quick-freezing mechanism, which includes an annular cooling groove at the upper end of the sampling cylinder. Multiple sliding rods are fixedly connected to the upper end of the sampling cylinder. A sliding ring is fixedly connected to the sidewalls of the multiple sliding rods. Each sidewall of the multiple sliding rods is fitted with a first spring. The lower ends of the multiple first springs are fixedly connected to the upper end of the sampling cylinder, and the upper ends of the multiple first springs are fixedly connected to the lower end of the sliding ring. A sealing ring is fixedly connected to the inner sidewall of the sliding ring. The sidewall of the sealing ring mates with the inner wall of the annular cooling groove. The annular cooling groove is filled with a low-temperature refrigerant consisting of a mixture of anhydrous ethanol and dry ice. The sampling cylinder is equipped with an adjustment mechanism to adjust the position of the sealing ring.

[0008] Preferably, the adjusting mechanism includes two first wedge plates, a connecting plate is fixedly connected between the two first wedge plates, an adjusting ring is fixedly connected to the upper end of the sealing ring by a plurality of rectangular rods, and a second wedge plate that cooperates with the two first wedge plates is fixedly connected to the lower end of the adjusting ring.

[0009] Preferably, a fixing plate is fixedly connected to the upper end of the sampling cylinder, and a sliding plate is slidably connected to the side wall of the fixing plate. One end of the sliding plate is fixedly connected to the side wall of one of the first wedge plates, and the other end of the sliding plate is fixedly connected to a third wedge plate. The side wall of the fixing plate is elastically connected to the side wall of the third wedge plate through multiple second springs, and a wedge strip that cooperates with the third wedge plate is fixedly connected to the side wall of the Z-shaped plate.

[0010] Preferably, a push plate is slidably connected to the inner wall of the sampling cylinder, and the upper end of the push plate is elastically connected to the top of the sampling cylinder through multiple third springs. Two push rods are slidably connected through the top of the sampling cylinder, and the lower ends of the two push rods are fixedly connected to the upper end of the push plate. The two push rods are located on both sides of the connecting plate.

[0011] Preferably, the sampling tube has four grooves evenly distributed on the inner wall near the conical tube. Each of the four grooves has a triangular plate slidably connected to its inner wall. The inner wall of the groove is elastically connected to the side wall of the triangular plate by multiple fourth springs. After the side walls of the four triangular plates fit together, they can completely block the inside of the sampling tube. A connecting pipe is fixedly connected between the inner walls of two adjacent grooves.

[0012] Preferably, a suction pump is fixedly connected to the upper end of the Z-shaped plate, and a liquid storage tank is fixedly connected to the upper end of the Z-shaped plate. One end of the suction pump is fixedly connected to the inner wall of the liquid storage tank, and the other end of the suction pump is fixedly connected to the top of one of the grooves through an infusion pipe.

[0013] Preferably, the sealing ring is provided with a mixing mechanism, the mixing mechanism including an annular drive groove formed in the inner side wall of the sealing ring, a plurality of vertical rods being rotatably connected through the inner wall of the annular drive groove, and a plurality of mixing rods being fixedly connected to the side wall of the plurality of vertical rods located below the sealing ring.

[0014] Preferably, a rotating ring is slidably connected to the bottom of the annular drive groove, and an internal gear ring is fixedly connected to the upper end of the ring. Gears are fixedly connected to the side walls of the multiple vertical rods located in the annular drive groove, and the side walls of the multiple gears mesh with the inner side walls of the internal gear ring. A motor is fixedly connected to the upper end of the sealing ring, and the output end of the motor is fixedly connected to the upper end of one of the vertical rods.

[0015] A soil sampling method for soil testing includes the following steps:

[0016] S1. Inject anhydrous ethanol into the annular cooling tank. At this time, the sealing ring is in the open state.

[0017] S2. Adjust the extension of the two electric push rods to drive the sampling tube and cone tube to cut into the soil layer, and the soil sample enters the sampling tube;

[0018] S3. After the soil sample reaches the preset depth, dry ice is added. At this time, the sealing ring moves down to close the annular cooling groove, forming an ultra-low temperature environment of -60℃ to 65℃.

[0019] S4. Stirring the refrigerant accelerates the solidification of frozen soil, while the suction pump drives the triangular plate to extend and close, cutting off and supporting the bottom of the soil sample.

[0020] S5. Adjust the two electric push rods to retract, which will move the sampling cylinder upwards. The unfrozen soil layer will fall off naturally, and the sealing ring will automatically move upwards and open.

[0021] S6. The suction pump reverses its rotation, causing the triangular plate to retract, while the push rod drives the pusher plate to completely eject the frozen soil sample.

[0022] Compared with existing technologies, the advantages of this invention are:

[0023] 1. By mixing anhydrous ethanol with dry ice as a low-temperature refrigerant and using a mixing mechanism for uniform heat transfer, soft soil with high water content can be rapidly frozen and solidified to prevent soil rheology, collapse, and stratification, thus preserving the original physical and chemical structure of the soil to the greatest extent and facilitating subsequent extraction.

[0024] 2. The four triangular plates extend synchronously and fit together to form a complete barrier layer below the soil sample. This not only cuts off the connection between the soil column and the lower soil layer, but also supports the frozen soil sample, preventing it from slipping or breaking during the lifting process.

[0025] 3. The sealing ring can open and close automatically. After sampling, the seal is released to allow the dry ice to dissipate quickly, stop the continuous cooling, prevent the soil sample from over-freezing and generating ice crystals that damage the pore structure, and facilitate the next sampling operation. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a soil sampling device for soil testing proposed in this invention;

[0027] Figure 2 for Figure 1 A schematic diagram of the vertical sectional structure;

[0028] Figure 3 for Figure 2 Enlarged structural diagram at point A;

[0029] Figure 4 for Figure 1 Schematic diagram of the sampling tube;

[0030] Figure 5 for Figure 4 Enlarged structural diagram at point B;

[0031] Figure 6 This is a top sectional view of a soil sampling device for soil testing proposed in this invention.

[0032] Figure 7 for Figure 3 Enlarged structural diagram at point C;

[0033] Figure 8 This is a schematic diagram of the mixing mechanism in a soil sampling device for soil testing proposed in this invention;

[0034] Figure 9 for Figure 1 A schematic diagram of the rear view structure.

[0035] In the diagram: 1. Z-shaped plate; 2. Electric push rod; 3. Sampling cylinder; 4. Conical cylinder; 5. Annular cooling tank; 6. Sliding rod; 7. Slip ring; 8. First spring; 9. Sealing ring; 10. Rectangular rod; 11. Adjusting ring; 12. First wedge plate; 13. Second wedge plate; 14. Fixing plate; 15. Sliding plate; 16. Second spring; 17. Third wedge plate; 18. Wedge strip; 19. Third spring; 20. Push plate; 21. Push rod; 22. Groove; 23. Triangular plate; 24. Fourth spring; 25. Connecting pipe; 26. Suction pump; 27. Liquid storage tank; 28. Infusion pipe; 29. ​​Annular drive groove; 30. Vertical rod; 31. Mixing rod; 32. Circular ring; 33. Internal gear ring; 34. Gear; 35. Motor. Detailed Implementation

[0036] The technical solutions of 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.

[0037] Reference Figures 1-9 A soil sampling device for soil testing includes a Z-shaped plate 1. Two electric push rods 2 are fixedly connected to the upper end of the Z-shaped plate 1. The output ends of the two electric push rods 2 are fixedly connected to a sampling cylinder 3. A conical cylinder 4 is fixedly connected to the lower end of the sampling cylinder 3 to reduce resistance when inserted into the soil layer and guide the soil sample into the sampling cylinder 3.

[0038] The inner walls of both the sampling cylinder 3 and the conical cylinder 4 are coated with a polytetrafluoroethylene low-temperature resistant and non-stick coating, which prevents the frozen soil from sticking to the cylinder wall and avoids tearing or damage when it is pushed out.

[0039] The sampling tube 3 is equipped with a quick-freezing mechanism, which is used to quickly solidify soft soil with high water content that is prone to collapse at low temperature, so as to avoid rheology, collapse and stratification after the soil is taken out, and to preserve the original physical and chemical structure of the soil to the greatest extent.

[0040] The quick-freezing mechanism includes an annular cooling tank 5 located at the upper end of the sampling cylinder 3. Multiple sliding rods 6 are fixedly connected to the upper end of the sampling cylinder 3. A slip ring 7 is fixedly connected to the side wall of the multiple sliding rods 6. A first spring 8 is sleeved on the side wall of each of the multiple sliding rods 6. The lower ends of the multiple first springs 8 are fixedly connected to the upper end of the sampling cylinder 3. The upper ends of the multiple first springs 8 are fixedly connected to the lower end of the slip ring 7. A sealing ring 9 is fixedly connected to the inner side wall of the slip ring 7. The side wall of the sealing ring 9 fits with the inner wall of the annular cooling tank 5. The annular cooling tank 5 is filled with a low-temperature refrigerant consisting of a mixture of anhydrous ethanol and dry ice.

[0041] Anhydrous ethanol, as a heat-conducting medium, can wet dry ice and slow down the sublimation rate of dry ice, while improving the uniformity of cold energy transfer. In this invention, the mass ratio of anhydrous ethanol to dry ice is 1:0.5, and its temperature can reach -60℃ to -65℃, which can rapidly freeze soft soil layers with high water content.

[0042] The sampling cylinder 3 is provided with an adjustment mechanism for adjusting the position of the sealing ring 9. The adjustment mechanism includes two first wedge plates 12, and a connecting plate is fixedly connected between the two first wedge plates 12. An adjustment ring 11 is fixedly connected to the upper end of the sealing ring 9 through multiple rectangular rods 10, and a second wedge plate 13 that cooperates with the two first wedge plates 12 is fixedly connected to the lower end of the adjustment ring 11.

[0043] A fixed plate 14 is fixedly connected to the upper end of the sampling cylinder 3. A sliding plate 15 is slidably connected to the side wall of the fixed plate 14. One end of the sliding plate 15 is fixedly connected to the side wall of one of the first wedge plates 12. The other end of the sliding plate 15 is fixedly connected to a third wedge plate 17. The side wall of the fixed plate 14 is elastically connected to the side wall of the third wedge plate 17 through multiple second springs 16. A wedge strip 18 that cooperates with the third wedge plate 17 is fixedly connected to the side wall of the Z-shaped plate 1.

[0044] When the sealing ring 9 moves downward into the annular cooling tank 5, it can seal the upper opening of the annular cooling tank 5 to prevent refrigerant from evaporating.

[0045] A push plate 20 is slidably connected to the inner wall of the sampling cylinder 3. The upper end of the push plate 20 is elastically connected to the top of the sampling cylinder 3 through multiple third springs 19. Two push rods 21 are slidably connected through the top of the sampling cylinder 3. The lower ends of the two push rods 21 are fixedly connected to the upper end of the push plate 20. The two push rods 21 are located on both sides of the connecting plate.

[0046] The sampling cylinder 3 has four grooves 22 evenly distributed on its inner wall near the conical cylinder 4. The inner walls of the four grooves 22 are all slidably connected to triangular plates 23. The inner walls of the grooves 22 are elastically connected to the side walls of the triangular plates 23 by multiple fourth springs 24. After the side walls of the four triangular plates 23 are in contact with each other, they can completely block the inside of the sampling cylinder 3. A connecting pipe 25 is fixedly connected between the inner walls of two adjacent grooves 22 to keep the liquid pressure in the four grooves 22 consistent.

[0047] When the four triangular plates 23 extend towards the center of the sampling tube 3 and fit together, they can completely block the internal channel of the sampling tube 3, cutting off the connection between the soil sample and the soil layer below.

[0048] It should be noted that the outer walls of the sampling tube 3, the conical tube 4, and the side walls of the triangular plate 23 are all equipped with heat insulation coatings, which can block the intrusion of ambient heat sources and heat from the lower soil into the low-temperature quick-freezing area, reduce cold loss, ensure uniform and stable freezing of soil samples, and eliminate problems such as local melting and uneven freezing.

[0049] A suction pump 26 is fixedly connected to the upper end of the Z-shaped plate 1, and a liquid storage tank 27 is fixedly connected to the upper end of the Z-shaped plate 1. One end of the suction pump 26 is fixedly connected to the inner wall of the liquid storage tank 27, and the other end of the suction pump 26 is fixedly connected to the top of one of the grooves 22 through the infusion pipe 28.

[0050] Furthermore, the suction pump 26 is a two-way gear pump, and the liquid inside the storage tank 27 is low-temperature resistant hydraulic oil (e.g., PAO synthetic oil or silicone oil, with a freezing point below -70°C).

[0051] When the suction pump 26 operates in the forward direction, hydraulic oil flows from the reservoir 27 through the delivery pipe 28 and the four connecting pipes 25 into the four grooves 22, pushing the triangular plate 23 to extend. When the suction pump 26 operates in the reverse direction, the hydraulic oil returns from the delivery pipe 28 and the four connecting pipes 25 to the reservoir 27, and the triangular plate 23 retracts under the elastic force of the fourth spring 24.

[0052] The sealing ring 9 is provided with a mixing mechanism, which includes an annular drive groove 29 opened on the inner side wall of the sealing ring 9. Multiple vertical rods 30 are rotatably connected through the inner wall of the annular drive groove 29. Multiple mixing rods 31 are fixedly connected to the side wall of the multiple vertical rods 30 located below the sealing ring 9.

[0053] Furthermore, the sealing ring 9 and the vertical rod 30 are fitted with a clearance to release the high-pressure gas generated by the sublimation of dry ice in the annular cooling tank 5 and eliminate negative pressure.

[0054] A rotating ring 32 is slidably connected to the bottom of the annular drive groove 29. An internal gear ring 33 is fixedly connected to the upper end of the ring 32. Gears 34 are fixedly connected to the side walls of multiple vertical rods 30 located in the annular drive groove 29. The side walls of multiple gears 34 mesh with the inner side walls of the internal gear ring 33. A motor 35 is fixedly connected to the upper end of the sealing ring 9. The output end of the motor 35 is fixedly connected to the upper end of one of the vertical rods 30.

[0055] A soil sampling method for soil testing includes the following steps:

[0056] S1. Inject anhydrous ethanol into the annular cooling tank 5. At this time, the sealing ring 9 is in the open state.

[0057] S2. Adjust the extension of the two electric push rods 2 to drive the sampling tube 3 and the conical tube 4 to cut into the soil layer, and the soil sample enters the sampling tube 3;

[0058] S3. After the soil sample reaches the preset depth, dry ice is added. At this time, the sealing ring 9 moves down to close the annular cooling groove 5, forming an ultra-low temperature environment of -60℃ to 65℃.

[0059] S4. Stirring the refrigerant accelerates the solidification of frozen soil. At the same time, the suction pump 26 rotates in the forward direction to extend and close the triangular plate 23, cutting off and supporting the bottom of the soil sample.

[0060] S5. Adjust the two electric push rods 2 to retract, which will drive the sampling cylinder 3 to move upward. The unfrozen soil layer will fall off naturally, and at this time the sealing ring 9 will automatically move upward and open.

[0061] S6, the suction pump 26 reverses its rotation to retract the triangular plate 23, and at the same time the push rod 21 drives the push plate 20 to push the frozen soil sample out completely.

[0062] In this invention, before sampling, the third wedge plate 17 and the sidewall of the wedge strip 18 are abutted together (e.g., Figure 3 As shown), multiple second springs 16 are compressed, and the slide plate 15 causes the two first wedge plates 12 to abut against the side walls of the two second wedge plates 13 respectively, so that the adjusting ring 11 drives the sealing ring 9 to be in a high-position open state through multiple rectangular rods 10. Then, the operator adds anhydrous ethanol as a low-temperature heat transfer medium into the annular cooling tank 5.

[0063] Then, the two electric push rods 2 are adjusted to extend synchronously, driving the sampling cylinder 3 and the conical cylinder 4 to move vertically downward and cut into the soft soil layer with high water content. During the downward movement of the sampling cylinder 3, the two push rods 21 will separate from the inner top surface of the Z-shaped plate 1. At this time, the push plate 20 moves upward to the initial position under the action of multiple third springs 19.

[0064] When the sampling is about to be completed (the height of the soil column is close to the preset value), the operator adds dry ice (the mass ratio of anhydrous ethanol to dry ice is 1:0.5) into the annular cooling tank 5. The dry ice and the existing anhydrous ethanol are mixed to form an ultra-low temperature refrigerant (-60℃ to -65℃). Then the sampling cylinder 3 continues to move down, so that the third wedge plate 17 separates from the wedge strip 18.

[0065] At this time, under the elastic force of multiple second springs 16, the third wedge plate 17 drives the two first wedge plates 12 to move and separate from the two second wedge plates 13 through the slide plate 15 and the connecting plate. At this time, the two second wedge plates 13 are not squeezed, and the multiple first springs 8 contract elastically, causing the slip ring 7 to drive the sealing ring 9 to move downward. The outer wall of the sealing ring 9 enters the annular cooling groove 5 to achieve sealing and prevent the refrigerant from evaporating and leaking.

[0066] Subsequently, the drive motor 35 rotates and drives the suction pump 26 to run in the forward direction. The motor 35 drives multiple vertical rods 30 and mixing rods 31 to continuously stir the refrigerant through the gear 34 and internal gear ring 33, accelerating the sublimation of dry ice and eliminating temperature stratification. This quickly forms a uniform low-temperature environment. The high-moisture soft soil layer is rapidly frozen and solidified by the low temperature of the inner wall of the sampling cylinder 3 to preserve its original structure. At the same time, the suction pump 26 draws liquid from the inside of the storage tank 27 and enters the four grooves 22 through the infusion pipe 28 and four connecting pipes 25. This pushes the four triangular plates 23 to stick together and close, forming a barrier sealing layer below the soil sample, cutting off the connection between the soil column and the soil below, and supporting the frozen soil column to prevent it from falling.

[0067] After the soil sample has solidified and blocked, the motor 35 is stopped from rotating, and the two electric push rods 2 are adjusted to retract and drive the sampling tube 3 to move upward and detach from the soil layer. The soft soil layer with high water content below the four triangular plates 23 will flow out under the action of gravity. Then, the third wedge plate 17 and the side wall of the wedge strip 18 are pressed together again, so that the sealing ring 9 moves upward to release the seal of the annular cooling groove 5, allowing room temperature air to enter. At this time, the dry ice dissipates quickly and stops absorbing heat, avoiding excessive freezing of the soft soil layer with high water content and causing soil cracking. The internal ice crystals destroy the original pore structure of the soil, making it convenient to refill anhydrous ethanol and dry ice for the next sampling.

[0068] Then the suction pump 26 reverses and draws the liquid from the four grooves 22 into the storage tank 27 through the infusion pipe 28 and four connecting pipes 25. At this time, the four triangular plates 23 are all contracted into the four grooves 22 under the action of multiple fourth springs 24, and no longer block the lower part of the frozen high moisture content soft soil layer.

[0069] As the sampling cylinder 3 continues to move upward, the two push rods 21 will abut against the inner top surface of the Z-shaped plate 1, causing the push plate 20 to move downward, thus pushing the frozen, high-moisture-content soft soil layer out of the sampling cylinder 3. Since the soil column has been rapidly frozen and solidified, it is not easy to break during the pushing process.

[0070] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A soil sampling device for soil testing, characterized in that, The plate includes a Z-shaped plate, with two electric push rods fixedly connected to the upper end of the Z-shaped plate. The output ends of the two electric push rods are fixedly connected to a sampling cylinder, and the lower end of the sampling cylinder is fixedly connected to a conical cylinder. The sampling cylinder is equipped with a quick-freezing mechanism, which includes an annular cooling groove at the upper end of the sampling cylinder. Multiple sliding rods are fixedly connected to the upper end of the sampling cylinder. A sliding ring is fixedly connected to the sidewalls of the multiple sliding rods. Each sidewall of the multiple sliding rods is fitted with a first spring. The lower ends of the multiple first springs are fixedly connected to the upper end of the sampling cylinder, and the upper ends of the multiple first springs are fixedly connected to the lower end of the sliding ring. A sealing ring is fixedly connected to the inner sidewall of the sliding ring. The sidewall of the sealing ring mates with the inner wall of the annular cooling groove. The annular cooling groove is filled with a low-temperature refrigerant consisting of a mixture of anhydrous ethanol and dry ice. The sampling cylinder is equipped with an adjustment mechanism to adjust the position of the sealing ring.

2. The soil sampling device for soil testing according to claim 1, characterized in that, The adjustment mechanism includes two first wedge plates, a connecting plate fixedly connected between the two first wedge plates, an adjustment ring fixedly connected to the upper end of the sealing ring by a plurality of rectangular rods, and a second wedge plate that cooperates with the two first wedge plates fixedly connected to the lower end of the adjustment ring.

3. A soil sampling device for soil testing according to claim 2, characterized in that, A fixed plate is fixedly connected to the upper end of the sampling cylinder. A sliding plate is slidably connected to the side wall of the fixed plate. One end of the sliding plate is fixedly connected to the side wall of one of the first wedge plates. A third wedge plate is fixedly connected to the other end of the sliding plate. The side wall of the fixed plate is elastically connected to the side wall of the third wedge plate through multiple second springs. A wedge strip that cooperates with the third wedge plate is fixedly connected to the side wall of the Z-shaped plate.

4. A soil sampling device for soil testing according to claim 2, characterized in that, A push plate is slidably connected to the inner wall of the sampling cylinder. The upper end of the push plate is elastically connected to the top of the sampling cylinder through multiple third springs. Two push rods are slidably connected through the top of the sampling cylinder. The lower ends of the two push rods are fixedly connected to the upper end of the push plate. The two push rods are located on both sides of the connecting plate.

5. A soil sampling device for soil testing according to claim 1, characterized in that, The sampling tube has four grooves evenly distributed on the inner wall near the conical tube. Each of the four grooves has a triangular plate that is slidably connected to its inner wall. The inner wall of the groove is elastically connected to the side wall of the triangular plate by multiple fourth springs. When the side walls of the four triangular plates are in contact with each other, they can completely block the inside of the sampling tube. A connecting pipe is fixedly connected between the inner walls of two adjacent grooves.

6. A soil sampling device for soil testing according to claim 5, characterized in that, A suction pump is fixedly connected to the upper end of the Z-shaped plate, and a liquid storage tank is fixedly connected to the upper end of the Z-shaped plate. One end of the suction pump is fixedly connected to the inner wall of the liquid storage tank, and the other end of the suction pump is fixedly connected to the top of one of the grooves through an infusion pipe.

7. A soil sampling device for soil testing according to claim 1, characterized in that, The sealing ring is provided with a mixing mechanism, which includes an annular drive groove formed on the inner side wall of the sealing ring. Multiple vertical rods are rotatably connected through the inner wall of the annular drive groove, and multiple mixing rods are fixedly connected to the side wall of the multiple vertical rods located below the sealing ring.

8. A soil sampling device for soil testing according to claim 7, characterized in that, A rotating ring is slidably connected to the bottom of the annular drive groove. An internal gear ring is fixedly connected to the upper end of the ring. Gears are fixedly connected to the side walls of the multiple vertical rods located in the annular drive groove. The side walls of the multiple gears mesh with the inner side walls of the internal gear ring. A motor is fixedly connected to the upper end of the sealing ring. The output end of the motor is fixedly connected to the upper end of one of the vertical rods.

9. A soil sampling method for soil testing, comprising a soil sampling device for soil testing as described in any one of claims 1-8, characterized in that, It also includes the following steps: S1. Inject anhydrous ethanol into the annular cooling tank. At this time, the sealing ring is in the open state. S2. Adjust the extension of the two electric push rods to drive the sampling tube and cone tube to cut into the soil layer, and the soil sample enters the sampling tube; S3. After the soil sample reaches the preset depth, dry ice is added. At this time, the sealing ring moves down to close the annular cooling groove, forming a low temperature environment of -60℃ to 65℃. S4. Stirring the refrigerant accelerates the solidification of frozen soil, while the suction pump drives the triangular plate to extend and close, cutting off and supporting the bottom of the soil sample. S5. Adjust the two electric push rods to retract, which will move the sampling cylinder upwards. The unfrozen soil layer will fall off naturally, and the sealing ring will automatically move upwards and open. S6. The suction pump reverses its rotation to retract the triangular plate, while the push rod drives the push plate to push the frozen soil sample out completely.

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