Large slurry stirring device and stirring method

Abstract

The invention discloses a large slurry stirring device and method, and belongs to the technical field of slurry stirring, and the large slurry stirring device comprises a support, a slurry stirring tank, a vacuum extraction unit and a control terminal. The slurry stirring tank is fixed to the support, a vacuum environment is formed through the vacuum extraction unit, the low-speed stirring unit and the high-speed stirring unit which rotate reversely are arranged in the slurry stirring tank, the low-speed stirring unit mixes soil and water in the tank body, and the high-speed stirring unit provides a speed gradient through a high-speed rotating cutter head to break the laminar boundary. Meanwhile, the low-speed stirring unit and the high-speed stirring unit rotate in opposite directions, so that the water and soil collision probability is greatly increased, the mixing and stirring efficiency is improved, and a saturated soil texture model conforming to a supergravity test is obtained. The vacuum extraction unit and the slurry stirring tank achieve whole-process automatic operation through the control terminal. The stirring device provided by the invention has the advantages of high stirring efficiency and high automation degree, and is suitable for preparing a large-scale supergravity test soil model.

Description

Technical Field

[0001] This invention relates to the field of mud mixing technology, specifically to a large-scale mud mixing device and mixing method. Background Technology

[0002] Model saturation is a crucial step in the preparation of soil models for high-gravity experiments, as the degree of saturation directly affects the model's response and test results. To achieve a high degree of saturation, model saturation must be carried out in a vacuum environment and maintained for an extended period. Sand models are saturated by placing the model in a vacuum saturation chamber and introducing liquid, while clay models require thorough mixing of a mud-water mixture in a vacuum environment to prepare a saturated slurry. During slurry preparation, a mixing device is used to thoroughly mix the soil and water to create the slurry required for the experiment.

[0003] Existing mud mixing devices use a single mixing structure for mixing, and the mixing speed is relatively fixed. This causes the mud to rotate in one direction during the mixing process, reducing the probability of collision between the soil and water inside the mixing device. This affects the mixing efficiency of the soil and water, resulting in low mixing efficiency and poor mixing effect of this single mixing structure. Therefore, there is an urgent need for a mud mixing device that can fully and efficiently mix soil and water. Summary of the Invention

[0004] To address the aforementioned problems, this invention incorporates two mixing units with different speeds and opposite directions within the tank. This allows the soil-water mixture inside the tank to rotate at different speeds at different locations within the tank, thereby improving mixing efficiency and dispersion. Simultaneously, the mixing device is automated through a control terminal, resulting in highly efficient mixing and a high degree of automation. This invention is suitable for preparing large-scale soil models for ultragravity experiments.

[0005] This invention provides a large-scale mud mixing device, including a support frame, a mud mixing tank, a vacuum extraction unit, and a control terminal; the mud mixing tank and the control terminal are fixed on the support frame, and the control terminal is used to control the mud mixing tank and the vacuum extraction unit; The mud mixing tank includes a tank body, a tank cover, a feeding unit, a water inlet unit, a low-speed mixing unit, a high-speed mixing unit, a venting valve, and a discharge assembly. The tank body is embedded in a support, and a tank cover is installed at the top of the tank body. The feeding unit and the water inlet unit are installed on the tank cover and are used to add soil and water to the tank body. The low-speed mixing unit includes a low-speed mixing rod, and the high-speed mixing unit includes a high-speed mixing rod. Both the low-speed mixing rod and the high-speed mixing rod are located inside the tank body. The low-speed mixing rod mixes the added soil and water, while the high-speed mixing rod centrifugally mixes the water-soil mixture at high speed. The high-speed mixing rod and the low-speed mixing rod rotate in opposite directions, and the distance between the high-speed mixing rod and the axis of the tank body is less than the distance between the low-speed mixing rod and the axis of the tank body. A venting valve is provided at the top of the tank cover for pressure relief, and a discharge assembly is connected to the bottom of the tank body for discharging the mixed mud. The vacuum extraction unit is connected to the mud mixing tank and is used to provide a vacuum environment for the mud mixing tank.

[0006] Preferably, the low-speed stirring rod includes a first rotating shaft, a connecting rod, a mixing rod, and a crushing blade; the first rotating shaft is vertically arranged on the axis of the tank and connected to the output end of the first speed regulator; two horizontally arranged connecting rods are symmetrically connected to the lower end of the first rotating shaft; the other end of the connecting rod is connected to the mixing rod; the mixing rod is arranged parallel to the first rotating shaft; and multiple crushing blades are provided on both the connecting rod and the mixing rod; the connecting rod, the mixing rod, and the crushing blades are used to crush large pieces of soil.

[0007] Preferably, the high-speed mixing rod includes a second rotating shaft, a locking nut, a high-speed distributing disc, and cutting teeth; the second rotating shaft is vertically arranged between the first rotating shaft and a mixing rod on one side and is connected to the output end of the second speed controller; the shaft wall of the second rotating shaft is fixed to the high-speed distributing disc by the locking nut; multiple cutting teeth are uniformly fixedly connected to the outer edge of the high-speed distributing disc; the cutting teeth are used to cut and disperse the water-soil mixture.

[0008] The present invention also provides a mixing method based on the aforementioned large-scale mud mixing device, comprising the following steps: S1: Close the vent valve and discharge assembly, add soil into the tank through the feeding unit, and add water into the tank through the water inlet unit. When the control terminal detects that the flow rates of soil and water in the feeding unit and water inlet unit reach the preset values, the control terminal controls the feeding unit and water inlet unit to stop feeding and watering. S2: The control terminal controls the vacuum extraction unit to continuously perform vacuuming operation on the mud mixing tank, so that a vacuum environment is formed inside the mud mixing tank. S3: The control terminal controls the start of the low-speed motor and the high-speed motor. The low-speed motor drives the low-speed mixing rod to rotate at low speed to mix the soil and water. After the soil and water form a water-soil mixture and enter a flowing state, the high-speed motor drives the high-speed mixing rod to rotate quickly to mix the water-soil mixture, thereby accelerating the mixing and dispersion of the soil and water. S4: After stirring is complete, the control terminal shuts off the low-speed motor and the high-speed motor, and controls the vacuum extraction unit to stop the vacuuming operation; S5: Open the vent valve to release pressure. After the pressure is released, open the discharge assembly and the slurry will enter the next process through the discharge assembly.

[0009] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes the cooperation of low-speed and high-speed stirring rods with different rotation speeds to actively break the laminar flow state during soil-water mixing by leveraging speed gradients and shear force differences. This significantly improves the uniformity and efficiency of mixing. Simultaneously, the low-speed and high-speed stirring rods rotate in opposite directions, further enhancing the mixing efficiency of soil and water. The V-shaped connecting rod, mixing rod, and crushing blade mounted on the low-speed stirring rod work together to crush large pieces of soil within the tank, while the high-speed rotation of the high-speed distributing disc quickly disperses the slurry, thereby improving mixing efficiency and effectiveness.

[0010] 2. This invention controls the operation of other modules through a PLC automatic control module and collects various data during the operation of the mixing device through a data acquisition module, thereby facilitating the staff to quickly understand the operating status of the device and realizing automatic control of the entire mixing device, effectively improving the convenience and intelligence of the mud mixing device operation. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure from another direction of the present invention; Figure 3 A schematic diagram showing the connection between the mud mixing tank and the support frame; Figure 4 This is a schematic diagram of the mud mixing tank. Figure 5 This is a schematic diagram of the mud mixing tank from another direction. Figure 6 A schematic diagram of the structure of a mud mixing tank after the tank body has been removed; Figure 7 A schematic diagram of the structure of a mud mixing tank from another direction after the tank body has been removed; Figure 8 This is a schematic diagram of the low-speed stirring rod and the high-speed stirring rod. Figure 9 This is a schematic diagram of the structure of a screw vacuum pump; Figure 10 This is a flowchart of the control terminal's operation.

[0012] In the diagram: 1. Support frame; 2. Slurry mixing tank; 3. Evacuation pipe; 4. Evacuation valve; 5. Screw vacuum pump; 6. Control terminal; 7. Tank body; 8. Tank cover; 9. Feed pipe; 10. Feed valve; 11. Water inlet pipe; 12. Water inlet valve; 13. First mounting pipe; 14. First speed controller; 15. Low-speed motor; 16. Low-speed stirring rod; 17. Second mounting pipe; 18. Second speed controller; 19. High-speed stirring rod; 20. High-speed motor; 21. Negative pressure transmitter; 22. Vent valve; 23. Discharge assembly; 24. Housing; 25. Touch screen display; 26. PLC automatic control module; 27. Data acquisition module; 28. Low-speed motor control module; 29. ​​High-speed motor control module. Modules: 30. First speed controller control module; 31. Second speed controller control module; 32. Feed valve control module; 33. Water inlet valve control module; 34. Air extraction valve control module; 35. Screw vacuum pump control module; 36. Sludge discharge pipe; 37. Sludge discharge control valve; 38. First rotating shaft; 39. Connecting rod; 40. Mixing rod; 41. Crushing blade; 42. Second rotating shaft; 43. Locking nut; 44. High-speed distributing disc; 45. Blade teeth; 46. First flange; 47. Second flange; 48. Sealing ring; 49. Observation tube; 50. Mounting frame; 51. Transparent observation plate; 52. Vertical frame; 53. Mounting platform; 54. Climbing ladder; 55. Conical bucket; 56. Guardrail. Detailed Implementation

[0013] 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.

[0014] This invention discloses a large-scale mud mixing device and mixing method. By using low-speed and high-speed mixing rods rotating in opposite directions inside the mud mixing tank, the water-soil mixture inside the tank obtains different rotational speed gradients and shear forces within the tank space. Combined with opposite rotational mixing directions, this significantly increases the probability of water-soil collision, improves the efficiency and effect of mixing, and thus obtains a saturated soil model that meets the requirements of hypergravity tests.

[0015] Figure 1 and Figure 2 This invention demonstrates a large-scale mud mixing device, including a support frame 1, a mud mixing tank 2, a vacuum extraction unit, and a control terminal 6. The vacuum extraction unit provides a vacuum environment for the mud mixing tank 2 and includes an extraction pipe 3, an extraction valve 4, and a screw vacuum pump 5, such as... Figure 9The vacuum pipe 3 connects the mud mixing tank 2 and the screw vacuum pump 5. The vacuum valve 4 is installed on the pipe wall of the vacuum pipe 3 near the mud mixing tank 2 and is used to control the vacuum efficiency.

[0016] The support frame 1 includes multiple vertical frames 52 and an installation platform 53. The vertical frames 52 support the installation platform 53, and the mud mixing tank 2 is embedded in the installation platform 53. Figure 3 A control terminal 6 is installed on the side of the bracket 1. The control terminal 6 includes a housing 24 and a touch screen 25, which constitute a human-machine interface, making it convenient for operators to adjust processing parameters according to the processing situation.

[0017] In this embodiment, the support frame 1 also includes a climbing ladder 54 and a guardrail 56. The climbing ladder 54 is installed on the side of the support frame 1, which makes it easier for workers to climb onto the installation platform 53 to operate the device and improves the convenience of device maintenance. The guardrail 56 is set around the installation platform 53 to prevent workers from falling from a height and effectively improves the safety of device use.

[0018] Figure 4 and Figure 5 The structure of the mud mixing tank 2 is shown from different angles. The mud mixing tank 2 includes a tank body 7, a tank cover 8, a feeding unit, a water inlet unit, a low-speed mixing unit, a high-speed mixing unit, a vent valve 22, a discharge assembly 23, and a negative pressure transmitter 21. The tank body 7 is fixedly embedded in the mounting platform 53, and the tank cover 8 is installed on the upper end of the tank body 7. The feeding unit includes a feeding pipe 9 and a feeding valve 10, and the water inlet unit includes a water inlet pipe 11 and a water inlet valve 12. The feeding pipe 9 and the water inlet pipe 11 are installed adjacent to each other on the tank cover 8. The feeding valve 10 is located on the wall of the feeding pipe 9 to control the inflow of soil, and the water inlet valve 12 is located on the wall of the water inlet pipe 11 to control the inflow of water.

[0019] In this embodiment, the tank body 7 and the tank cover 8 are disassembled and assembled via flanges. The first flange is fixed to the upper end of the tank body 7, and the second flange is fixed to the lower end of the tank cover 8. A sealing ring 48 is provided between the first flange 46 and the second flange 47 to ensure the airtightness of the device.

[0020] In this embodiment, the upper ends of the feed pipe 9 and the water inlet pipe 11 are both connected to a conical hopper 55. The diameter of the upper end of the conical hopper 55 is larger than the diameter of the lower end, which can improve the convenience of adding soil and water to the feed pipe 9 and the water inlet pipe 11, and effectively improve the convenience of using the device.

[0021] like Figure 6 and Figure 7As shown, the low-speed stirring unit includes a first mounting pipe 13, a first speed regulator 14, a low-speed motor 15, and a low-speed stirring rod 16. The first mounting pipe 13 is installed at the center of the tank cover 8. The upper end of the first mounting pipe 13 is connected to the first speed regulator 14. The upper end of the first speed regulator 14 is the input end, and the lower end is the output end. Its input end is connected to the output end of the low-speed motor 15, and its output end is connected to the low-speed stirring rod 16. The high-speed stirring unit includes a second mounting pipe 17, a second speed regulator 18, a high-speed stirring rod 19, and a high-speed motor 20. The second mounting pipe 17 is installed on the side of the first mounting pipe 13 away from the feeding unit and the water inlet unit. The upper end of the second mounting pipe 17 is connected to the second speed regulator 18. The upper end of the second speed regulator 18 is the input end, and the lower end is the output end. Its input end is connected to the output end of the high-speed motor 20, and its output end is connected to the high-speed stirring rod 19. Both the high-speed stirring rod 19 and the low-speed stirring rod 16 are located inside the tank 7. The low-speed stirring rod 16 is located on the outer periphery of the tank 7, stirring the added soil and water. This prevents the soil with low moisture content from adhering to the inner wall of the tank 7 and increases the contact area between the soil and water, allowing water to more easily penetrate the soil pores and accelerating the increase in soil moisture content, thus allowing the soil-water mixture to reach a suspended state more quickly. Furthermore, the low-speed stirring rod 16 prevents soil from accumulating at the discharge assembly due to gravity, maintaining a stable suspended state of the slurry within the tank. The high-speed stirring rod 19 performs high-speed centrifugal stirring of the soil-water mixture. The high-speed stirring rod 19 rotates in opposite directions to the low-speed stirring rod 16, and is located within the laminar flow range caused by the rotation of the low-speed stirring rod 16. The high-speed centrifugal stirring of the soil-water mixture by the high-speed stirring rod 19 breaks up any clumps of soil, ensuring thorough mixing and creating layers with different flow velocities. These slurry layers with different flow velocities diffuse into each other, ultimately achieving thorough dispersion and mixing. The top of the tank cover 8 is equipped with a negative pressure transmitter 21 and a vent valve 22. The negative pressure transmitter 21 converts the negative pressure inside the tank 7 into an electrical signal and feeds it back to the control terminal 6. The vent valve 22 is used to release pressure. The bottom of the tank 7 is connected to a discharge assembly 23, which includes a mud discharge pipe 36 connected to the center of the bottom of the tank 7 and a mud discharge control valve 37 on the wall of the mud discharge pipe 36, used to control the discharge of the mixed mud from the mud mixing tank 2. In this embodiment, the tank cover 8 is connected to an inclined observation pipe 49. The upper end of the observation pipe 49 is equipped with a mounting frame 50, and a transparent observation plate 51 is embedded in the mounting frame 50, which facilitates the observation of the inside of the tank 7 by the staff, so as to determine whether the device is operating normally by observing the state of the mud inside.

[0022] like Figure 8As shown, the low-speed mixing rod 16 includes a first rotating shaft 38, a connecting rod 39, a mixing rod 40, and a crushing blade 41. The first rotating shaft 38 is vertically arranged on the axis of the tank body 7 and connected to the output end of the first speed regulator 14. Two horizontally arranged V-shaped connecting rods 39 are symmetrically connected to the lower end of the first rotating shaft 38. The other end of the connecting rod 39 is connected to the mixing rod 40. The mixing rod 40 is arranged parallel to the first rotating shaft 38. Multiple crushing blades 41 are arranged on both the connecting rod 39 and the mixing rod 40. The connecting rod 39, the mixing rod 40, and the crushing blades 41 are used to crush large pieces of soil. When the device is working, the first rotating shaft 38 drives the connecting rod 39 to rotate, the connecting rod 39 drives the two mixing rods 40 to rotate, and the two mixing rods 40 drive the multiple crushing blades 41 to rotate, thereby crushing large pieces of soil and effectively improving the mixing effect and efficiency of water and soil.

[0023] The high-speed mixing rod 19 includes a second rotating shaft 42, a locking nut 43, a high-speed distributing disc 44, and cutting teeth 45. The second rotating shaft 42 is vertically arranged between the first rotating shaft 38 and a mixing rod 40 on one side and is connected to the output end of the second speed controller 18. The shaft wall of the second rotating shaft 42 is fixed with two high-speed distributing discs 44 by the locking nut 43. Multiple cutting teeth 45 are uniformly fixedly connected to the outer edge of the high-speed distributing discs 44. The cutting teeth 45 are used to cut and disperse the water-soil mixture. In use, the second rotating shaft 42 drives the two high-speed distributing discs 44 to rotate at high speed. The two high-speed distributing discs 44 can drive the multiple cutting teeth 45 to rotate and cut and disperse the clumps of soil in the water-soil mixture, thereby improving the mixing effect. The low-speed mixing rod 16 and the high-speed mixing rod 19 cooperate with each other. Their different rotation speeds cause the soil-water mixture inside the tank 7 to be at different rotation speeds and directions, breaking the laminar flow boundary of the water-soil mixture. At the same time, the low-speed mixing rod 16 and the high-speed mixing rod 19 rotate in opposite directions, further improving the mixing efficiency of soil and water.

[0024] The control terminal 6 includes a housing 24, a touch screen display 25, a PLC automatic control module 26, a data acquisition module 27, a low-speed motor control module 28, a high-speed motor control module 29, a first speed regulator control module 30, a second speed regulator control module 31, a feed valve control module 32, a water inlet valve control module 33, an air extraction valve control module 34, and a screw vacuum pump control module 35. Figure 10The PLC automatic control module 26 is connected to all other modules; the low-speed motor control module 28 is electrically connected to the low-speed motor 15 and is used to control the start and stop of the low-speed motor 15; the high-speed motor control module 29 is electrically connected to the high-speed motor 20 and is used to control the start and stop of the high-speed motor 20; the first speed regulator control module 30 is electrically connected to the first speed regulator 14 and adjusts the speed of the low-speed motor 15 by controlling the first speed regulator 14; the second speed regulator control module 31 is electrically connected to the second speed regulator 18 and adjusts the speed of the high-speed motor 20 by controlling the second speed regulator 18; the feed valve control module 3... The control module 2 is connected to the feed valve 10, and adjusts the feed rate by controlling the feed valve 10; the water inlet valve control module 33 is connected to the water inlet valve 12, and adjusts the water inlet rate by controlling the water inlet valve 12; the vacuum valve control module 34 is connected to the vacuum valve 4, and adjusts the vacuuming efficiency by controlling the vacuum valve 4; the screw vacuum pump control module 35 is electrically connected to the screw vacuum pump 5, and is used to control the opening and closing of the screw vacuum pump 5; the data acquisition module 27 collects various data during the operation of the mixing device and feeds them back to the PLC automatic control module, which then controls the other modules to make corresponding adjustments to the connecting components. The control terminal 6 realizes automatic control of the entire mixing device, effectively improving the convenience and intelligence of the mud mixing device operation.

[0025] The present invention also provides a mixing method based on the aforementioned large-scale mud mixing device, comprising the following steps: S1: When making mud, the discharge assembly 23 and the vent valve 22 are closed. The PLC automatic control module 26 controls the opening of the feed valve 10 and the water inlet valve 12 through the feed valve control module 32 and the water inlet valve control module 33. Soil is added into the tank 7 through the feed pipe 9 and water is added into the tank 7 through the water inlet pipe 11. When the data acquisition module 27 detects that the flow rate of soil and water through the feed pipe 9 and the water inlet pipe 11 reaches the preset value, the PLC automatic control module 26 controls the closing of the feed valve 10 and the water inlet valve 12 through the feed valve control module 32 and the water inlet valve control module 33, and the feed pipe 9 and the water inlet pipe 11 stop water intake. S2: The PLC automatic control module 26 controls the opening of the air extraction valve 4 through the air extraction valve control module 34, and at the same time starts the screw vacuum pump 5 through the screw vacuum pump control module 35. The screw vacuum pump 5 continuously evacuates the inside of the tank 7 through the air extraction pipe 3, so that a vacuum environment is formed inside the mud mixing tank 2. S3: The data acquisition module 27 acquires the electrical signal fed back by the negative pressure transmitter 21. After confirming that a vacuum environment has been formed inside the mud mixing tank 2, the PLC automatic control module 26 starts the low-speed motor 15 and the high-speed motor 20 through the low-speed motor control module 28 and the high-speed motor control module 29. The low-speed motor 15 drives the low-speed stirring rod 16 to rotate at a low speed to mix water and soil. After the soil and water form a water-soil mixture and enter a flowing state, the high-speed motor 20 drives the high-speed stirring rod 19 to rotate quickly to accelerate the dispersion and mixing of soil and water. According to the mixing situation fed back by the data acquisition module 27, the PLC automatic control module 26 controls the first speed controller 14 and the second speed controller 18 through the first speed controller control module 30 and the second speed controller control module 31, thereby adjusting the speed of the low-speed motor 15 and the high-speed motor 20 so that the low-speed stirring rod 16 and the high-speed stirring rod 19 obtain a suitable speed to accelerate the mixing and dispersing of soil and water. S4: After the process is completed, the PLC automatic control module 26 shuts down the low-speed motor 15 and the high-speed motor 20 through the low-speed motor control module 28 and the high-speed motor control module 29, and shuts down the vacuum valve 4 and the screw vacuum pump 5 through the vacuum valve control module 34 and the screw vacuum pump control module 35, thus stopping the vacuuming operation. S5: Open the vent valve 22 to release pressure. The data acquisition module 27 collects the electrical signal fed back by the negative pressure transmitter 21. After confirming that the slurry mixing tank 2 has been depressurized, the discharge assembly 23 is opened. The slurry is discharged through the discharge assembly 23 and enters the next process, completing the rapid processing of the slurry.

[0026] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0027] 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 large-scale mud mixing apparatus, characterized by: The mud stirring tank (2) comprises a tank body (7), a tank cover (8), a feeding unit, a water feeding unit, a low-speed stirring unit, a high-speed stirring unit, a degassing valve (22) and a discharging assembly (23); the tank body (7) is embedded on the support (1), and the upper end of the tank body (7) is provided with the tank cover (8); the feeding unit and the water feeding unit are installed on the tank cover (8) and used for adding soil and water into the tank body (7); the low-speed stirring unit comprises a low-speed stirring rod (16), and the high-speed stirring unit comprises a high-speed stirring rod (19); the low-speed stirring rod (16) and the high-speed stirring rod (19) are located in the tank body (7) and used for stirring the added soil and water and high-speed centrifugal stirring the water-soil mixture; the rotation direction of the high-speed stirring rod (19) is opposite to that of the low-speed stirring rod (16), and the distance between the high-speed stirring rod (19) and the axis of the tank body (7) is smaller than that between the low-speed stirring rod (16) and the axis of the tank body (7); the top of the tank cover (8) is provided with the degassing valve (22) for pressure relief, and the bottom of the tank body (7) is connected with the discharging assembly (23) for discharging the stirred mud. The vacuum extraction unit is connected with the mud stirring tank (2) and used for providing a vacuum environment for the mud stirring tank (2). The feeding unit comprises a feeding pipe (9) and a feeding valve (10), and the water feeding unit comprises a water feeding pipe (11) and a water feeding valve (12); the feeding pipe (9) and the water feeding pipe (11) are adjacently installed on the tank cover (8), the feeding valve (10) is arranged on the wall of the feeding pipe (9) and used for controlling the inflow amount of the soil, and the water feeding valve (12) is arranged on the wall of the water feeding pipe (11) and used for controlling the inflow amount of the water.

2. A large-scale mud mixing device according to claim 1, characterized in that: The low-speed stirring unit further comprises a first mounting pipe (13), a first speed regulator (14) and a low-speed motor (15); the first mounting pipe (13) is mounted on the center of the tank cover (8), the first speed regulator (14) is mounted on the upper end of the first mounting pipe (13), the upper end of the first speed regulator (14) is an input end, the lower end is an output end, the input end is connected with the output end of the low-speed motor (15), and the output end is connected with the low-speed stirring rod (16).

3. A large-scale mud mixing device according to claim 1, characterized in that: The high-speed stirring unit further comprises a second mounting pipe (17), a second speed regulator (18) and a high-speed motor (20); the second mounting pipe (17) is mounted on the side, away from the feeding unit and the water feeding unit, of the first mounting pipe (13), and the components are connected in the same way as the low-speed stirring unit. The vacuum extraction unit comprises an air extraction pipe (3), an air extraction valve (4) and a screw vacuum pump (5); the air extraction pipe (3) is connected between the mud stirring tank (2) and the screw vacuum pump (5), the air extraction valve is arranged on the wall of the air extraction pipe (3) close to the mud stirring tank (2) and used for controlling the vacuum extraction efficiency.

4. A large-scale mud mixing device according to claim 1, characterized in that: ​ 5. A large-scale mud mixing device according to claim 1, characterized in that: The discharge assembly (23) comprises a sludge outlet pipe (36) and a sludge outlet control valve (37), the sludge outlet pipe (36) is located at the center of the bottom of the tank body (7), and the sludge outlet control valve (37) is fixed on the sludge outlet pipe (36).

6. A large-scale mud mixing apparatus according to claim 1, characterized in that: The low-speed stirring rod (16) comprises a first rotating shaft (38), a connecting rod (39), a mixing rod (40) and a crushing blade (41); the first rotating shaft (38) is vertically arranged on the axis of the tank body (7) and is connected with the output end of the first speed regulator (14), the lower end of the first rotating shaft (38) is symmetrically connected with two horizontally arranged connecting rods (39), the other end of the connecting rod (39) is connected with the mixing rod (40), the mixing rod (40) is arranged in parallel with the first rotating shaft (38), and a plurality of crushing blades (41) are arranged on the connecting rod (39) and the mixing rod (40); the connecting rod (39), the mixing rod (40) and the crushing blade (41) are used for crushing the large block of soil.

7. A large-scale mud mixing device according to claim 1, characterized in that: The high-speed stirring rod (19) comprises a second rotating shaft (42), a locking nut (43), a high-speed distributing disc (44) and a cutter tooth (45); the second rotating shaft (42) is vertically arranged between the first rotating shaft (38) and one side of the mixing rod (40) and is connected with the output end of the second speed regulator (18), the shaft wall of the second rotating shaft (42) is fixed with the high-speed distributing disc (44) through the locking nut (43), and a plurality of cutter teeth (45) are uniformly and fixedly connected to the outer edge of the high-speed distributing disc (44); the cutter tooth (45) is used for cutting and scattering the water-soil mixture.

8. A large-scale mud mixing apparatus according to claim 1, characterized in that: The upper end of the tank body (7) is fixed with a first flange plate (46), the lower end of the tank cover (8) is fixed with a second flange plate (47), a sealing rubber ring (48) is arranged between the first flange plate (46) and the second flange plate (47) to ensure the air tightness of the inside of the slurry mixing tank (2), and the tank body (7) and the tank cover (8) are connected through the first flange plate (46) and the second flange plate (47).

9. A large-scale mud mixing apparatus according to claim 1, characterized in that: The tank cover (8) is further provided with a negative pressure transmitter (21), which converts the negative pressure in the tank body (7) into an electric signal and feeds back to the control terminal (6).

10. A mixing method based on the large-scale mud mixing device according to claim 3, characterized by, The method comprises the following steps: S1: close the air release valve (22) and the discharge assembly (23), add soil into the tank body (7) through the feeding unit, and add water into the tank body (7) through the water feeding unit; when the control terminal collects the flow of soil and water of the feeding unit and the water feeding unit to reach a preset value, the control terminal controls the feeding unit and the water feeding unit to stop feeding and water feeding; S2: the control terminal controls the vacuum extraction unit to continuously extract vacuum on the slurry mixing tank (2), so that a vacuum environment is formed in the slurry mixing tank (2); S3: the control terminal controls the low-speed motor (15) and the high-speed motor (20) to start, the low-speed motor (15) drives the low-speed stirring rod (16) to rotate at low speed to stir the soil and water, and after the soil and water form a water-soil mixture and enter a flow state, the high-speed motor (20) drives the high-speed stirring rod (19) to rotate at high speed to stir the water-soil mixture, so as to accelerate the mixing and dispersion of the soil and water; S4: after the stirring is completed, the control terminal closes the low-speed motor (15) and the high-speed motor (20), and controls the vacuum extraction unit to stop the vacuum extraction operation. S5: open the air release valve (22) to release pressure, and open the discharge assembly (23) after the pressure is released, and the slurry enters the next process through the discharge assembly (23).

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