A stirring grouting device for microbial solidification of soft soil

Abstract

The invention discloses a stirring grouting device for microbial solidification of soft soil, comprising a stirring grouting device for solidifying soft soil, a bearing frame is provided at the bottom end of a rotating bearing in the center below a bearing plate of the solidifying soft soil stirring grouting device, a stirring frame is provided on a movable shaft inside the bearing frame, a liquid injection port is symmetrically provided inside the stirring frame, stirring rods are equidistantly provided below the stirring frame, a grouting pipe is provided inside the stirring rod, stirring blades and grouting plugs are symmetrically provided on the outer wall of the stirring frame, the grouting plugs are connected to the grouting pipe, and a drill bit is provided at the bottom end of the stirring rod. The stirring grouting device for solidifying soft soil adopts soil stirring and grouting to carry out soil stirring and grouting at the same time, which reduces the time difference between grouting and stirring, reduces the influence of pore throat blockage between soil particles caused by the soil body solidifying first near the grouting port during the grouting process on the flow of bacterial liquid, and injects bacterial liquid and cementing liquid into different parts of the soil body during the stirring process through continuous grouting, so that the initial grouting at different depths in the soil body can be evenly distributed.

Description

Technical Field

[0001] The invention relates to the technical field of stirring grouting for microbial solidified soft soil, in particular to a stirring grouting device for microbial solidified soft soil. Background Art

[0002] Soft soil generally refers to fine-grained soil with a gray appearance, a natural porosity greater than or equal to 1.0, and a natural water content greater than the liquid limit. It is mostly distributed in relatively low-lying areas such as my country's coasts, lakeshores, and riverbanks. It has special engineering geological properties such as high natural water content, high porosity, high compressibility, low strength, creep, and thixotropy, and its engineering geological conditions are relatively poor. When selecting soft soil for foundation applications, practical reinforcement technical measures are often required. Common soil reinforcement methods include mechanical compaction and chemical grouting, but both treatment measures have the problems of high energy consumption, high cost, and pollution and damage to the environment. The use of microbial induced calcium carbonate precipitation (MICP) technology for soil reinforcement has the advantages of being green, environmentally friendly, efficient, and economical. Therefore, the use of microbial induced calcium carbonate precipitation technology is being increasingly used in soil reinforcement.

[0003] MICP technology primarily involves four methods: urea hydrolysis, denitrification, ferric iron reduction, and sulfate reduction. Urea reduction is widely used due to its relatively simple hydrolysis mechanism, easily controllable reaction process, and ability to produce large amounts of CO₃₁⁻ in a short period of time. The MICP principle for urea hydrolysis is as follows: Bacillus pasteurianus is typically used to hydrolyze urea to produce urease, which decomposes urea into NH₄⁺ and CO₃⁻. The CO₃⁻ reacts with Ca₂⁺ in the binder to form calcium carbonate crystals. These crystals fill the gaps between soil particles, increasing soil density and friction between them. Furthermore, the calcium carbonate crystals act as a cementing agent, increasing interparticle cohesion.

[0004] Based on the general principles of MICP soil consolidation technology based on urea hydrolysis, it is known that during the soil consolidation process, microbially induced calcium carbonate crystals can block soil pores, narrowing the pores and hindering the flow of microorganisms, thus reducing the soil consolidation effect. Therefore, to maximize the effectiveness of microbial soil consolidation, a suitable grouting method must be adopted to ensure a uniform reaction between the microorganisms and the binder within the soil. Currently, commonly used grouting methods include injection, immersion, and spraying. Injection is the most common method for MICP reactions. By injecting bacterial solution and nutrient solution into the soil, the injection rate and pressure can be effectively controlled, allowing for quantitative analysis of grouting methods. The immersion method completely immerses the specimen in the bacterial solution or nutrient solution, allowing the natural infiltration of the liquid to gradually form calcium carbonate precipitates. The spraying method simply sprays the bacterial solution or nutrient solution onto the soil surface, allowing the solution to penetrate the soil due to gravity.

[0005] Liang Shihua and other researchers compared and analyzed the injection and immersion methods and found that the step-by-step grouting injection method is more effective for consolidating sand than the immersion method. When spraying is used to consolidate deep soils, calcium carbonate crystals may form in the upper soil, blocking the pores between particles. This can lead to uneven distribution of the bacterial solution and cementing fluid during infiltration. Therefore, injection is a reasonable and efficient method for deep soil reinforcement.

[0006] Microbial soil consolidation has many advantages, but there are still some problems in its application. Some scholars pointed out that microbial technology has been widely verified to be able to effectively reinforce soil, but the industry generally has the problem of uneven soil after reinforcement. Some areas have high strength but there are still weak and easily damaged links. How to effectively overcome the heterogeneity of reinforced soil is a major difficulty. Usually in the process of microbial soil consolidation grouting, as the cement is generated, the pores of the soil are gradually blocked, and the permeability of the soil gradually decreases. After multiple rounds of grouting, it will eventually form a blockage and it will be impossible to continue to inject. In addition, some scholars have conducted experiments simulating real-life microbial soil consolidation. Studies have shown that the strength of soil in similar areas is similar, and the farther away from the grouting port, the smaller the compressive strength of the soil. At the same time, in traditional grouting methods, microorganisms in the soil near the grouting point will first induce the formation of calcium carbonate crystals. The formed calcium carbonate cement will reduce the pore throats between soil particles, restrict the flow of bacterial solution or cementing solution, hinder the seepage of bacterial solution and cementing solution, and make the calcium carbonate crystals induced by microorganisms unevenly distributed in the soil. Therefore, an improved technology is urgently needed to solve this problem existing in the existing technology. Summary of the Invention

[0007] The object of the present invention is to provide a solidified soft soil mixing and grouting device with a load-bearing frame at the bottom end of the rotating bearing in the center below the load-bearing plate, a stirring frame is provided on the movable shaft inside the load-bearing frame, liquid injection ports are symmetrically provided inside the stirring frame, stirring rods are equidistantly provided below the stirring frame, a grouting pipe is provided inside the stirring rod, stirring blades and grouting plugs are symmetrically provided on the outer wall of the stirring frame, the grouting plugs are connected to the grouting pipe, and a drill bit is provided at the bottom end of the stirring rod. The device adopts soil mixing and grouting at the same time, which shortens the time difference between grouting and mixing, and reduces the influence of the blockage of pores and throats between soil particles caused by the early consolidation of the soil near the grouting port during the grouting process on the flow of bacterial liquid. By continuous grouting, the bacterial liquid and the cementing liquid are injected into different parts of the soil during the stirring process, so that the initial grouting at different depths in the soil body can be evenly distributed, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above-mentioned object, the present invention provides the following technical solution: a stirring grouting device for microbial solidification of soft soil, comprising a solidified soft soil stirring grouting device, wherein a load-bearing plate is provided on the solidified soft soil stirring grouting device, a rotary bearing is provided at the center below the load-bearing plate, a load-bearing frame is provided at the bottom end of the rotary bearing, a movable shaft is provided at equal intervals inside the load-bearing frame, and both end ends of the movable shaft are fixedly connected to the inner wall of the load-bearing frame respectively, a stirring frame is provided on the movable shaft, and the stirring frame and the movable shaft are installed in coordination;

[0009] The stirring frame has symmetrical liquid injection ports on both sides of the interior, stirring rods are arranged at equal intervals at the lower interior of the stirring frame, stirring blades are symmetrically arranged on both sides of the outer wall of the stirring rod, the stirring blades are welded to the outer wall of the stirring rod, a grouting pipe is provided in the vertical direction of the inner center of the stirring rod, the grouting pipe is connected to the top of the stirring rod, the other two side walls of the stirring rod are provided with slurry outlets, a grouting plug is provided inside the stirring rod, the grouting plug is installed in conjunction with the grouting pipe and the slurry outlet, a drill bit is provided at the bottom end of the stirring rod, and the drill bit and the stirring rod are an integrated structure.

[0010] Preferably, the outer C-shaped channel steel bracket of the load-bearing frame and the inner side walls on both sides of the load-bearing frame are symmetrically provided with horizontal push rods, the horizontal push rods are horizontally arranged, one end of the horizontal push rod is vertically fixedly connected to the inner wall of the load-bearing frame, and the other end of the horizontal push rod is fixedly connected to the side wall of the stirring frame, and the horizontal push rod is a DT type electric push rod.

[0011] Preferably, movable shaft mounting grooves are provided at equal intervals inside the stirring frame, and the movable shaft mounting grooves pass through the stirring frame.

[0012] Preferably, two plugs are symmetrically provided on the grouting plug, the plugs are installed in conjunction with the slurry outlet, a spring is provided between the two plugs, and the end of the spring is fixedly connected to the center of one side surface of the plug.

[0013] Preferably, the stirring blade forms an angle of 30° with the horizontal direction.

[0014] Preferably, the solidified soft soil mixing and grouting device is connected to an external power system and an electronic control system, and the connection lines of the external power system and the electronic control system pass through the load-bearing plate and are connected to the rotary bearing.

[0015] Preferably, a grouting method for a stirring grouting device for microbial solidification of soft soil comprises the following steps:

[0016] Step 1: Use the lifting structure to sink the solidified soft soil mixing grouting device into the soft soil base;

[0017] Step 2: Inject the binder solution and bacterial solution into the device through the injection ports on both sides of the stirring frame. After the injection is completed, connect the air pressure sensor and the air compressor to the injection port. When stirring begins, the stirring device is controlled by an external electronic system to perform rotational stirring around the rotating bearing and horizontal stirring along the moving axis. During this process, the air pressure provided by the air compressor is controlled by the air pressure valve to control the injection rate of the binder solution and bacterial solution respectively as needed.

[0018] Step 3: Continuously inject the bacterial solution and the cementing liquid into the soil layers at different depths while stirring. The bacterial solution and the cementing liquid injected into the soil below the depth and part of the soil are in contact with each other and evenly distributed under the stirring action, so that the bacterial solution evenly induces the formation of calcium carbonate crystals in the soil, thereby achieving a good soil consolidation effect.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) A stirring frame is provided on the movable shaft, and movable shaft mounting grooves are provided at equal intervals inside the stirring frame. The movable shaft mounting grooves penetrate the stirring frame. The stirring frame and the movable shaft are installed in coordination. The bearing plate is responsible for bearing the weight of the lower structure and is connected to a crane, an oil source, etc. The bearing frame of the device can rotate around a rotating bearing, thereby achieving the purpose of rotary stirring;

[0021] (2) The drill bit is responsible for breaking off some hard soil samples when the stirring device descends into the soft soil. The stirring rod is connected to the stirring frame and can rotate around the central axis on the stirring frame. Under the action of the external lifting device, the stirring rod can rotate and sink into the soft soil base. The stirring frame is connected to the moving shaft. The stirring rod will stir and disturb the soft soil during the stirring process. The stirring blade is responsible for increasing the stirring area of the stirring rod during the stirring process, so that the stirring treatment of the soft soil foundation is more uniform.

[0022] (3) The bacterial solution and the cementing solution are injected into the soil layer simultaneously through different injection ports to avoid premature reaction and formation of calcium carbonate crystals due to the simultaneous injection of the mixed solution of the two. The bacterial solution and the cementing solution injected initially can freely seep into the soil without cementation or restriction of the soil pores. During the process of stirring to make the two uniformly distributed in the soil, the bacterial solution and the cementing solution come into contact with each other in the soil, so that the bacterial solution uniformly induces the formation of calcium carbonate crystals in the soil, thereby achieving a good soil consolidation effect.

[0023] (4) The grouting port is connected to the grouting plug and is used to inject slurry into the soft soil base. The grouting plug is composed of two grouting cover plates connected by springs. The springs connected to the grouting plugs at different heights of the stirring rod have different stiffnesses. The spring stiffness near the upper part of the stirring rod is larger. The increased spring stiffness is used to balance the pressure of different deep soil layers that need to be overcome when grouting into the soil, so that the slurry discharge rate of each slurry port is consistent under the same pressure. The spring stiffness at different positions can be selected according to the pressure distribution inside the soil. There are two upper and lower baffles inside the slurry port to block and fix the grouting cover plate under the action of the spring, so that the grouting cover plate just blocks the grouting port;

[0024] (5) The solidified soft soil mixing grouting device uses soil mixing and grouting to shorten the time difference between grouting and mixing, and reduces the impact of blockage of pores and throats between soil particles caused by the soil solidifying first near the grouting port on the flow of bacterial liquid, so that the bacterial liquid and cementing liquid are more evenly distributed in the soil. By continuously grouting, the bacterial liquid and cementing liquid are injected into different parts of the soil during the mixing process, so that the initial grouting at different depths in the soil can be evenly distributed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural schematic diagram of the solidified soft soil stirring grouting device of the present invention;

[0026] Figure 2 This is a cross-sectional view of the solidified soft soil stirring grouting device of the present invention;

[0027] Figure 3 This is a side view of the solidified soft soil stirring grouting device of the present invention;

[0028] Figure 4 This is a schematic diagram of the stirring rod structure of the present invention;

[0029] Figure 5 This is a side view of the stirring rod of the present invention;

[0030] Figure 6 This is a schematic diagram of the load-bearing frame of the present invention;

[0031] Figure 7 Schematic diagram of the stirring frame of the present invention;

[0032] Figure 8 Schematic diagram of the grouting plug mechanism of the present invention.

[0033] In the figure: 1. Solidified soft soil mixing and grouting device; 2. Bearing plate; 3. Rotary bearing; 4. Bearing frame; 5. Moving shaft; 6. Mixing frame; 7. Liquid injection port; 8. Mixing rod; 9. Grouting pipe; 10. Mixing blade; 11. Slurry outlet; 12. Drill bit; 13. Grouting plug; 14. Horizontal push rod. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] See also Figure 1-8 The present invention provides a technical solution: a stirring grouting device for microbial solidification of soft soil, comprising a solidified soft soil stirring grouting device 1, a load-bearing plate 2 is provided on the solidified soft soil stirring grouting device 1, a rotary bearing 3 is provided at the center below the load-bearing plate 2, a load-bearing frame 4 is provided at the bottom end of the rotary bearing 3, a movable shaft 5 is provided at equal intervals inside the load-bearing frame 4, and both end ends of the movable shaft 5 are fixedly connected to the inner wall of the load-bearing frame 4 respectively, a stirring frame 6 is provided on the movable shaft 5, and a movable shaft mounting groove is provided at equal intervals inside the stirring frame 6, and the movable shaft mounting groove passes through the stirring frame 6, and the stirring frame 6 is installed in coordination with the movable shaft 5, the load-bearing plate 2 is responsible for bearing the weight of the lower structure, and is connected to a crane, an oil source, etc. The load-bearing frame 2 of the device can rotate around the rotary bearing 3, thereby achieving the purpose of rotary stirring.

[0036] The load-bearing frame 4 is supported by a C-shaped channel steel bracket, and horizontal push rods 14 are symmetrically arranged inside the side walls of both sides of the load-bearing frame 4. The horizontal push rods 14 are arranged horizontally, and one end of the horizontal push rod 14 is vertically fixedly connected to the inner wall of the load-bearing frame 4, and the other end of the horizontal push rod 14 is fixedly connected to the side wall of the stirring frame 6. The horizontal push rod 14 is a DT type electric push rod.

[0037] Liquid injection ports 7 are symmetrically provided on both sides of the interior of the stirring frame 6. The liquid injection ports 7 are connected to the slurry outlets 11 of the two adjacent stirring rods 8. They are used to inject the binder and bacterial solution after the stirring device sinks into the soft soil base. After the injection is completed, the air pressure sensor and the air compressor are connected. The air pressure is changed according to the reading of the air pressure sensor, thereby controlling the injection rate of the binder and bacterial solution.

[0038] The bacterial solution and the cementing liquid are injected into the soil layer simultaneously through different injection ports, so as to avoid premature reaction and formation of calcium carbonate crystals due to the simultaneous injection of the mixed solution of the two. The bacterial solution and the cementing liquid injected initially can freely seep into the soil without cementation and restriction of the soil pore throat. In the process of stirring to make the two uniformly distributed in the soil, the bacterial solution and the cementing liquid contact each other in the soil, so that the bacterial solution evenly induces the formation of calcium carbonate crystals in the soil, thereby achieving a good soil consolidation effect.

[0039] The bacterial solution and the cementing liquid are injected into the soil layer simultaneously through different grouting ports to avoid premature reaction and formation of calcium carbonate crystals due to the simultaneous injection of the mixed solution of the two. The bacterial solution and the cementing liquid initially injected can freely seep into the soil without cementation and restriction of the soil pores. In the process of stirring to make the two uniformly distributed in the soil, the bacterial solution and the cementing liquid contact each other in the soil, so that the bacterial solution evenly induces the formation of calcium carbonate crystals in the soil, thereby achieving a good soil consolidation effect.

[0040] Stirring rods 8 are provided at equal intervals at the lower part of the interior of the stirring frame 6, and stirring blades 10 are symmetrically provided on both sides of the outer wall of the stirring rod 8. The stirring blades 10 form an angle of 30° with the horizontal direction, and the stirring blades 10 are welded to the outer wall of the stirring rod 8. A grouting pipe 9 is provided in the vertical direction of the inner center of the stirring rod 8, and the grouting pipe 9 is connected to the top of the stirring rod 8. The other two side walls of the stirring rod 8 are provided with slurry outlets 11. A grouting plug 13 is provided inside the stirring rod 8, and two plugs are symmetrically provided on the grouting plug 13. The plugs are installed in coordination with the slurry outlet. A spring is provided between the two plugs, and the end of the spring is fixedly connected to the center of one side surface of the plug. The grouting plug 13 is installed in coordination with the grouting pipe 9 and the slurry outlet 11. A drill bit 12 is provided at the bottom end of the stirring rod 8, and the drill bit 12 and the stirring rod 8 are an integrated structure.

[0041] The slurry outlet 11 is connected to the grouting plug 13 and is used to inject slurry into the soft soil base. The grouting plug is composed of two grouting cover plates connected by springs. The springs connected to the grouting plugs 13 distributed at different heights of the stirring rod 8 have different stiffnesses. The spring stiffness near the upper part of the stirring rod 8 is larger. The increased spring stiffness is used to balance the pressure of different deep soil layers that need to be overcome when grouting into the soil, so that the slurry discharge rate of each slurry outlet 11 is consistent under the same pressure. The spring stiffness at different positions can be selected according to the pressure distribution inside the soil; there are two upper and lower baffles inside the slurry outlet, which are used to block and fix the grouting cover plate under the action of the spring, so that the grouting cover plate just blocks the grouting outlet.

[0042] The drill bit 12 is responsible for breaking off some hard soil samples when the stirring device descends into the soft soil. The stirring rod 8 is connected to the stirring frame 6 and can rotate around the central axis on the stirring frame 6. Under the action of the external lifting device, the stirring rod can rotate and sink into the soft soil base. The stirring frame 6 is connected to the movable shaft 5. The stirring rod 8 will stir and disturb the soft soil during the stirring process. The stirring blade 10 is responsible for increasing the stirring area of the stirring rod 6 during the stirring process, so that the soft soil foundation stirring treatment is more uniform.

[0043] The solidified soft soil mixing grouting device 1 is connected to an external power system and an electronic control system. The connection line of the external power system and the electronic control system passes through the load-bearing plate and is connected to the rotary bearing, providing a power source for the rotation of the rotary bearing 3 and realizing electronic control, and then passes through the load-bearing plate 4 and is connected to the horizontal push rod 14, providing a power source for the pushing and contraction of the horizontal push rod 14 and realizing electronic control, and then passes through the movable shaft 5 and is connected to the stirring frame 6, providing a power source for the rotation of the stirring rod 8 and realizing electronic control.

[0044] A grouting method for a stirring grouting device for microbial solidification of soft soil includes: using a lifting structure to sink the solidified soft soil stirring grouting device 1 into the soft soil base, and injecting the binder solution and the bacterial solution into the device through the injection ports 7 on both sides of the stirring frame 6. After the injection is completed, the injection port 7 is connected to the air pressure sensor and the air compressor. When stirring begins, the stirring device is controlled by an external electronic system to perform rotational stirring around the rotating bearing 3 and horizontal stirring along the movable axis 5. During this process, the air pressure valve is used to control the size of the power air pressure provided by the air compressor, and the injection rate of the binder solution and the bacterial solution is controlled according to needs.

[0045] The bacterial solution and the cementing liquid are continuously injected into the soil layers at different depths while stirring. The bacterial solution and the cementing liquid injected to a depth less than the soil body come into contact with each other and are evenly distributed under the stirring action, so that the bacterial solution evenly induces the formation of calcium carbonate crystals in the soil body, thereby achieving a good soil consolidation effect.

[0046] The solidified soft soil mixing grouting device performs soil mixing and grouting simultaneously, shortening the time difference between grouting and mixing, and reducing the impact of blockage of pores and throats between soil particles caused by the initial consolidation of soil near the grouting port on the flow of bacterial liquid, so that the bacterial liquid and cementing liquid are more evenly distributed in the soil. By continuous grouting, the bacterial liquid and cementing liquid are injected into different parts of the soil during the mixing process, so that the initial grouting at different depths in the soil can be evenly distributed.

[0047] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A stirring grouting device for microbial solidification of soft soil, comprising a solidification soft soil stirring grouting device (1), characterized in that: The solidified soft soil mixing grouting device (1) is provided with a load-bearing plate (2), a rotary bearing (3) is provided at the center below the load-bearing plate (2), a load-bearing frame (4) is provided at the bottom end of the rotary bearing (3), and movable shafts (5) are provided at equal intervals inside the load-bearing frame (4), and both end heads of the movable shafts (5) are respectively fixedly connected to the inner wall of the load-bearing frame (4), and a stirring frame (6) is provided on the movable shaft (5), and the stirring frame (6) is installed in conjunction with the movable shaft (5); Liquid injection ports (7) are symmetrically provided on both sides of the interior of the stirring frame (6), stirring rods (8) are equidistantly provided on the interior lower portion of the stirring frame (6), stirring blades (10) are symmetrically provided on both sides of the outer wall of the stirring rod (8), the stirring blades (10) are welded to the outer wall of the stirring rod (8), a grouting pipe (9) is provided in the vertical direction of the center of the interior of the stirring rod (8), the grouting pipe (9) is communicated with the top end of the stirring rod (8), slurry outlets (11) are provided on the other two side walls of the stirring rod (8), a grouting plug (13) is provided inside the stirring rod (8), the grouting plug (13) is installed in conjunction with the grouting pipe (9) and the slurry outlet (11), a drill bit (12) is provided at the bottom end of the stirring rod (8), and the drill bit (12) and the stirring rod (8) are an integrated structure; The grouting plug (13) is symmetrically provided with two plugs, which are installed in conjunction with the slurry outlet, and a spring is provided between the two plugs, the end of the spring is fixedly connected to the center of one side surface of the plug; The slurry outlet (11) is connected to the grouting plug (13). The grouting plug (13) is composed of two grouting cover plates connected by springs. The springs connected to the grouting plugs distributed at different heights of the stirring rod (8) have different stiffnesses, and the spring near the upper part of the stirring rod (8) has a larger stiffness.

2. The stirring grouting device for microbial solidification of soft soil according to claim 1, characterized in that: The load-bearing frame (4) is provided with a C-shaped channel steel bracket outside, and horizontal push rods (14) are symmetrically provided inside the side walls of both sides of the load-bearing frame (4). The horizontal push rods (14) are arranged horizontally, and one end of the horizontal push rod (14) is vertically fixedly connected to the inner wall of the load-bearing frame (4), and the other end of the horizontal push rod (14) is fixedly connected to the side wall of the stirring frame (6). The horizontal push rod (14) is a DT type electric push rod.

3. The stirring grouting device for microbial solidification of soft soil according to claim 1, characterized in that: The interior of the stirring frame (6) is provided with movable shaft mounting grooves at equal intervals, and the movable shaft mounting grooves penetrate the stirring frame (6).

4. The stirring grouting device for microbial solidification of soft soil according to claim 1, characterized in that: The stirring blade (10) forms an angle of 30° with the horizontal direction.

5. The stirring grouting device for microbial solidification of soft soil according to claim 1, characterized in that: The solidified soft soil mixing grouting device (1) is connected to an external power system and an electronic control system, and the connection lines of the external power system and the electronic control system pass through the bearing plate and are connected to the rotary bearing.

6. A grouting method for implementing the stirring grouting device for microbial solidification of soft soil according to claim 1 comprises the following steps: Step 1: using a lifting structure to lower the solidified soft soil mixing and grouting device (1) into the soft soil base; Step 2: Inject the binder liquid and the bacterial liquid into the device through the liquid injection ports (7) on both sides of the stirring frame (6), respectively. After the injection is completed, connect the air pressure sensor and the air compressor to the liquid injection port (7). When stirring begins, the stirring device is controlled by the external electronic system to perform rotational stirring around the rotating bearing (3) and horizontal stirring along the moving axis (5). During this process, the air pressure provided by the air compressor is controlled by the air pressure valve to control the size of the power pressure, and the injection rate of the binder liquid and the bacterial liquid is controlled according to the needs. Step 3: Continuously inject the bacterial solution and the cementing liquid into the soil layers at different depths while stirring. The bacterial solution and the cementing liquid injected into the soil below the depth and part of the soil are in contact with each other and evenly distributed under the stirring action, so that the bacterial solution evenly induces the formation of calcium carbonate crystals in the soil, thereby achieving a good soil consolidation effect.

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