A device for preparing fiber-reinforced soil based on density adjustment and semi-suspension dispersion

Abstract

The utility model discloses a kind of fiber solidified soil preparation devices based on density adjustment and semi-suspension dispersion, including density adjustment and fiber dispersion system, dehydration system and mixing system sequentially arranged according to material conveying direction;Density adjustment and fiber dispersion system include density adjustment bin and support device, agitator and on-line densimeter are equipped in bin, on-line densimeter is connected with PLC controller signal, and PLC controller receives the signal of on-line densimeter and controls water inlet valve opening and closing;Density adjustment bin is connected with dehydration system by slurry pump, fiber slurry is handled into mud cake after dehydration system, then, it is sent into mixing system and solidified agent mixes again.By adjusting slurry density to be similar to fiber density, it fundamentally eliminates the density difference and surface tension that cause fiber to form group, so that fiber is easily dispersed in liquid environment, and creates favorable conditions for subsequent uniform mixing.

Description

Technical Field

[0001] This utility model belongs to the field of civil engineering equipment, and specifically relates to a fiber-solidified soil preparation device based on density adjustment and semi-suspended dispersion. Background Technology

[0002] Fiber-stabilized soil is a composite material in which fiber materials (such as polypropylene fibers and glass fibers) are incorporated into the soil and solidified using a curing agent (such as cement or lime). The addition of fibers effectively improves the tensile and crack resistance of the soil and is widely used in roadbed reinforcement, slope protection, backfilling projects, and other fields.

[0003] However, a common technical challenge in existing fiber-reinforced soil preparation processes is that fibers are prone to clumping and uneven dispersion during mixing. This is mainly due to the lightweight and hydrophobic nature of fibers. When directly added to a viscous, dense slurry, the density difference and surface tension between the fibers and the slurry cause them to entangle rather than disperse. Even with high-intensity mixing, it is difficult to break up the clumps of fibers, resulting in uneven fiber distribution in the finished product, creating weak points that severely restrict the fiber reinforcement effect and cause the actual mechanical properties of the material to be far lower than the theoretical values.

[0004] Currently, most industry efforts focus on improving the form and strength of the mixing device itself, but the results are limited and energy consumption is high. Therefore, there is an urgent need for a new technical solution that can fundamentally solve the problem of uniform fiber dispersion in slurry from the perspective of process principles. Utility Model Content

[0005] To address the problems of fiber clumping and uneven dispersion in viscous slurry in existing technologies, this invention provides a fiber-solidified soil preparation device based on density adjustment and semi-suspension dispersion.

[0006] The present invention adopts the following technical solution: A fiber-stabilized soil preparation device based on density regulation and semi-suspension dispersion includes a density regulation and fiber dispersion system, a dewatering system, and a final mixing system arranged sequentially in the material conveying direction. The density adjustment and fiber dispersion system includes a density adjustment chamber and a support device. The top of the density adjustment chamber is equipped with a slurry conveying port and a fiber feeding port, and the side wall is equipped with a water inlet valve. The chamber is equipped with a stirring device and an online density meter, and the bottom is equipped with a discharge port. The online density meter is connected to a PLC controller, and the PLC controller is connected to the water inlet valve. The PLC controller receives the signal from the online density meter and controls the opening and closing of the water inlet valve. It is used to dynamically adjust the opening and closing of the water inlet valve according to the slurry density value fed back by the online density meter, so as to stabilize the slurry density in the chamber within a preset target density range.

[0007] The density adjustment chamber and the dewatering system are connected by a mud pump. After the fiber mud is processed into mud cake by the dewatering system, it is sent to the mixing system to be mixed with the curing agent.

[0008] This invention first adjusts the slurry density to approximately the fiber density, allowing the fibers to easily disperse evenly in a semi-suspended state under stirring. After dehydration, a uniformly distributed fiber mixture is obtained. Finally, a curing agent is added and mixed. This method effectively prevents fiber clumping, significantly improves the uniformity of fiber distribution in the cured soil, and thus enhances the mechanical properties of the finished material.

[0009] Preferably, the target density range preset in the PLC controller is set based on the density of the input fiber, and the target density value is between 1.01 times and 1.10 times the fiber density.

[0010] Its core working principle lies in adjusting the slurry density to be close to that of the fiber density, so that the gravity and buoyancy of the fiber in the static slurry are nearly balanced, and the fiber is in a critical suspension state. In this state, the external stirring force only needs to overcome the fluid viscosity to achieve uniform fiber dispersion, without having to overcome gravity or buoyancy to tear the fiber clumps, thus fundamentally solving the problem of fiber clumping and achieving low-energy consumption and high-efficiency uniform mixing.

[0011] Preferably, the stirring device includes a stirring shaft located at the center and six stirring blades symmetrically distributed on the stirring shaft. The stirring blades have a spiral structure, and the connecting shaft of the stirring blades is detachably connected to the stirring shaft. A scraper is connected to one end of the connecting shaft near the inner wall of the density adjustment chamber.

[0012] The mixing device generates high-intensity shearing action, rapidly breaking up fiber bundles and achieving full dispersion of fibers in low-viscosity slurry. The mixing blades rotate vertically close to the bin wall, effectively eliminating dead zones and scraping material from the edges towards the center, thus aiding in achieving uniform mixing throughout the entire area.

[0013] Compared to the traditional method of high-intensity stirring in viscous slurry in an attempt to break up fiber clumps, this invention performs the main dispersion operation in a low-resistance environment, resulting in a significant reduction in energy consumption.

[0014] Preferably, the dewatering system is a plate and frame filter press. By controlling the dewatering pressure and time, the moisture content of the dewatered fiber-reinforced soil can be precisely controlled.

[0015] Preferably, the mixing system is a twin-shaft forced mixer, which is a crushing and mixing integrated machine. The feed inlet of the integrated machine receives the fiber-mixed soil discharged from the dewatering system, which is used to initially crush and disperse the compacted soil blocks and prepare for mixing with the curing agent. The top of the machine is equipped with a curing agent feeding port and a water inlet.

[0016] The twin-shaft forced mixer has two mixing shafts rotating in opposite directions, which can apply strong extrusion, shearing and convection to dry or semi-dry materials to ensure that the curing agent and fiber-reinforced soil are mixed evenly.

[0017] The mixing system inlet is connected to the dewatering system outlet. A curing agent feeding port is set at the top of the system to uniformly mix the dewatered fiber-mixed soil, curing agent and water. Finally, the finished fiber-cured soil is output through the outlet for subsequent processing.

[0018] This utility model has the following beneficial effects: 1. By adjusting the slurry density to be close to the fiber density, the density difference and surface tension that cause fiber clumping are fundamentally eliminated, making the fibers easy to disperse in the liquid environment and creating favorable conditions for subsequent uniform mixing.

[0019] 2. Shearing and stirring in a low-viscosity, near-neutral suspension slurry improves fiber dispersion efficiency and virtually eliminates clumping. The resulting fiber-reinforced soil product has a uniform fiber distribution, fully leveraging its tensile and crack-strengthening effects to significantly enhance the material's mechanical properties and engineering reliability.

[0020] 3. This utility model organically integrates functional modules such as automatic density adjustment, efficient dispersion, miniaturized dehydration, precise moisture content control, and final mixing to form a complete production line with a compact layout and clear process. It is very suitable for large-scale industrial production and has extremely high practical value. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the density adjustment and fiber dispersion system. Figure 3 This is a schematic diagram of a mud pump structure; Figure 4 This is a schematic diagram of the dehydration system. Figure 5 This is a schematic diagram of the filter section. Figure 6 This is a schematic diagram of the final mixing system structure; The attached diagram lists the components represented by each number as follows: 1-Density adjustment and fiber dispersion system; 2-Fiber slurry conveying pipe; 3-Slurry pump; 4-Dewatering system; 5-Mixing system; 6-Density adjustment bin; 7-Support device; 8-Slurry conveying port; 9-Fiber feeding port; 10-Water inlet valve; 11-Online density meter; 12-PLC controller; 13-Agitator; 14-Agitator shaft; 15-Agitator blades; 16-Discharge port of adjustment bin; 17-Motor; 18-Bearing frame; 19-Suction chamber; 20-Coupling; 21-Rotor; 22-Filter press inlet; 23-Filtration section; 24-Hydraulic system; 25-Liquid outlet; 26-Frame section; 27-Cake collection frame; 28-Filter frame; 29-Filter cloth; 30-Filter plate; 31-Cake inlet; 32-Cure agent inlet; 33-Water inlet; 34-Crushing and mixing integrated machine; 35-Fiber solidified soil outlet. Detailed Implementation

[0022] The technical solutions of the present utility model will be further described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0023] This embodiment provides a device for preparing fiber-stabilized soil based on density adjustment and semi-suspension dispersion, such as... Figure 1 As shown, it includes a density adjustment and fiber dispersion system 1, a dewatering system 4, and a mixing system 6. The density adjustment and fiber dispersion system 1 and the dewatering system 4 are connected by a fiber slurry delivery pipe 2 and a slurry pump 3.

[0024] like Figure 2 As shown, the density adjustment and fiber dispersion system 1 includes a density adjustment chamber 6 and a supporting device 7 below it. The supporting device 7 is a rigid frame welded from channel steel and angle steel, fixed to the ground with anchor bolts, providing a stable base for the entire density adjustment chamber 6. A slurry conveying port 8 and a fiber feeding port 9 are opened at the top of the density adjustment chamber 6. Initial slurry (such as slurry formed by pretreatment of river silt, slag, etc.) is fed into the density adjustment chamber through the slurry conveying port 8. Engineering fibers are fed into the density adjustment chamber through the fiber feeding port 9. The engineering fibers are quantitatively and continuously conveyed to the fiber feeding port 9 and then into the density adjustment chamber via a screw conveyor or other conveying method, achieving quantitative and continuous addition of engineering fibers.

[0025] A water inlet valve 10 is installed on the side wall of the density regulating chamber for connecting to an external water source. A stirring device 13 is vertically installed in the center of the chamber. This device includes a central stirring shaft 14 and six symmetrically distributed stirring blades 15 on the shaft. The stirring blades have a spiral structure, and their connecting shafts are detachably connected to the shaft. A scraper is connected to one end of the connecting shaft near the inner wall of the chamber. The stirring shaft 14 is driven by an electric motor located at the bottom of the chamber via a reduction gear, providing the main shearing force. The stirring shaft 14 drives the stirring blades to rotate, and the scraper close to the inner wall scrapes the material on the inner wall surface as it rotates with the shaft (the scraper is not shown in the figure). An online density meter 11 is also installed inside the chamber to monitor the slurry density in real time. The online density meter 11 is connected to a PLC controller 12, and the output of the PLC controller 12 is connected to the water inlet valve 10 to achieve automatic density control.

[0026] like Figure 1 , 3 The discharge port 16 at the bottom of the density regulating chamber 6 is connected to the feed port 22 of the plate and frame filter press via a pipeline through the mud pump 3. The outlet of the mud pump 3 is connected to the feed port 22 of the plate and frame filter press via a high-pressure pipeline.

[0027] like Figure 3 As shown, the mud pump 3 is an anti-clogging, low-shear single-screw pump, mainly comprising a motor 17, a coupling 20, a suction chamber 19, a rotor 21, a stator, and a bearing bracket 18. The motor 17 drives the rotor 21 to rotate eccentrically within the stator via the coupling 20, thereby forming multiple axially continuously advancing sealed volumetric cavities between the rotor and stator, achieving stable volumetric transport of the medium. Based on the principle of volumetric transport, this pump type, due to its continuous cavities, uniform flow velocity, absence of high-speed rotating or shearing elements within the pump chamber, and low operating speed, effectively prevents the fibrous medium from being cut or entangled during transport, thus maintaining the original length and strength of the fibers, and possessing the characteristics of low shear and anti-clogging. The mud pump 3 is existing technology.

[0028] The pump inlet is designed with a gradually expanding flared shape to ensure smooth entry of fibrous materials and prevent inlet blockage. The rotor 21 is lined with ultra-high molecular weight polyethylene (UHMW-PE) or undergoes high-precision polishing, significantly reducing the surface friction coefficient and preventing fiber adhesion. The pump's mechanical seal adopts an external or bellows design to prevent fiber intrusion into the sealing area and improve operational reliability. The diameter of the delivery pipe connected to the pump outlet is not less than 80mm, and the elbow adopts a large-radius design (curvature radius R ≥ 5 times the pipe diameter) to minimize flow resistance and fiber retention.

[0029] like Figure 4As shown, the dewatering system 4 in this embodiment adopts a small plate and frame filter press, whose structure mainly includes a frame part 26, a filtration part 23, a hydraulic system 24, a filter press inlet 22, a liquid outlet 25, and a cake collection frame 27.

[0030] like Figure 5 As shown, the filtration section 23 includes multiple filter frames 28, filter plates 30, and filter cloth 29. The filter cloth 29, as the filter medium that directly intercepts solids, is preferably made of polyester or polypropylene material with a smooth surface, low adhesion, and easy cake removal. The fit between the filter frames 28 and the filter plates 30, and the clamping method of the filter cloth 29, are conventional designs in the art. The powerful clamping force provided by the hydraulic system 24 ensures that no leakage occurs in each filter chamber during high-pressure filtration. The specific structure and principle of the plate and frame filter press are existing technologies; the working process is briefly described here: 1. Filter Plate Pressing and Preparation Stage: The hydraulic system 24 receives instructions from the PLC controller 12 and begins operation. The hydraulic system 24 tightly presses all the filter plates 30 and filter frames 28 together to form sealed filter chambers. At this time, the filter cloth in each filter chamber is in a ready-to-use state.

[0031] 2. Feeding, Filling, and Pressure Filtration Stage: The slurry pump 3 starts, pumping the fiber slurry into the filter press through the feed inlet 22. As the slurry is continuously injected, all filter chambers are filled synchronously. Under the pumping pressure (0.8~1.0 MPa), free water in the slurry passes through the micropores of the filter cloth 29, enters the water flow channel on the surface of the filter plate 30, and is finally discharged from the outlet 25; while solid particles (soil particles and fibers) are trapped by the filter cloth 29, gradually forming a slurry cake in the cavity of the filter frame 28. As filtration proceeds, the slurry cake gradually thickens, and the filtration resistance increases accordingly. The slurry pump automatically maintains or slightly increases the output pressure to overcome the resistance and ensure the dewatering process continues. This stage is controlled by the PLC controller 12 and lasts for approximately 15-25 minutes.

[0032] 3. Unloading Stage: After dewatering, the mud pump 3 stops, and the PLC controller 12 controls the hydraulic system 24 to return, loosening the filter plates. Each filter chamber opens sequentially, and the formed filter cake automatically peels off from the filter cloth under its own weight, falling into the mud cake collection frame 27 below and being transported to the mixing system 6. For some mud cakes that are difficult to detach, a vibrator or automatic scraper device or manual assistance can be used for unloading.

[0033] Based on preliminary experiments, an optimal "dewatering pressure-time" curve program was established and stored in the PLC controller 12 for slurries with different soil types and initial moisture contents. During the dewatering process, the PLC controller 12 first controls the hydraulic system 24 to press the filter plates of the filter press, and then starts the slurry pump 3 to feed material into the filter chamber. After feeding is completed, the system enters the pressurization dewatering stage. The PLC controller 12 controls the hydraulic system 24 to increase the pressure and stabilize it at a preset value (usually 0.8 MPa ~ 1.2 MPa). The PLC controller 12 precisely controls the duration of the high-pressure holding stage through a built-in timer, thereby controlling the dewatering endpoint within the preset range, and ultimately stabilizing the moisture content of the fiber-reinforced soil within the required range (e.g., 25% ~ 30%).

[0034] like Figure 6 As shown, the core of the mixing system 5 is a twin-shaft forced mixer, namely, a crushing and mixing integrated machine 34. The feed inlet of this integrated machine receives fiber-mixed soil blocks from the discharge outlet of the dewatering system 4. At the top of the integrated machine 34, there are a solidifying agent feed inlet 32 ​​and a water inlet 33. The discharge end of the mixing system 5 has a fiber-solidified soil discharge outlet 35 for outputting finished fiber-solidified soil for subsequent processing. The discharge end of the mixing system 6 has a fiber-solidified soil discharge outlet 23 for outputting finished fiber-solidified soil for subsequent processing.

[0035] The working principle and process of the fiber-stabilized soil preparation device based on density adjustment and semi-suspension dispersion provided by this utility model are as follows: The following describes the specific implementation of this utility model in detail using the production of fiber-reinforced soil with added polypropylene (PP) fibers as an example, but the implementation of this utility model is not limited thereto.

[0036] Step 1: Equipment Preparation and Parameter Setting. Verify that all system connections are correct. Introduce polypropylene fibers through fiber inlet 9; their density is approximately 0.91 g / cm³. On the PLC controller 12 interface, the operator sets the target mud density of the density adjustment chamber 6 to 1.00 g / cm³, with an allowable fluctuation range of ±0.03 g / cm³. This target value is approximately 1.1 times the fiber density. Simultaneously, select or input the "dehydration pressure-time" program for the current soil type into the PLC.

[0037] Step 2: Initial mud feeding. The raw soil material is initially mixed with water to form an initial mud slurry with a density of approximately 1.60 g / cm³. The initial mud slurry is then pumped into the density regulating chamber 6 through the mud slurry delivery port 8.

[0038] Step 3: Density Adjustment and Fiber Dispersion. Start the dual-drive stirring device 13. The low-speed spiral mixer 15 operates at 60 rpm to prevent material deposition on the bin walls; the high-speed shear mixer 14 operates at 1200 rpm to provide strong shear. Activate the automatic control mode of the online densitometer 11 and PLC controller 12. Based on real-time feedback data from the densitometer, the PLC controller 12 dynamically controls the water inlet valve 10 to inject water into the bin. When the slurry density drops to approximately 1.10 g / cm³, begin continuously and uniformly adding metered PP fibers through the fiber feeding port 9. The strong eddies and shear forces generated by the high-speed shear mixer 14 immediately act on the fibers, achieving initial dispersion. Continue adding water until the online densitometer 11 displays a stable slurry density of 1.00 g / cm³ for 2 minutes. At this point, there is no visible agglomeration of fibers in the bin, exhibiting a uniformly distributed semi-suspended state. The PLC controller 12 then closes the water inlet valve 10, completing this step.

[0039] If fibers are added directly to high-density mud, they will quickly float to the surface, making it difficult for them to penetrate the central area of ​​the mud and hindering dispersion. Gradually adding water from 1.60 → 1.10 → 1.00 g / cm³ to reduce the mud density creates a more favorable buoyancy and fluidity environment for fiber dispersion. Diluting the mud to approximately 1.1 times the fiber density places the fibers in a semi-suspended state, preventing them from rapidly floating or sinking, making them easier to disperse evenly through shear mixing. The reduced viscosity and increased fluidity of the diluted mud further enhance the effectiveness of high-speed shear mixing, resulting in more thorough fiber dispersion.

[0040] Step 4: Dewatering process. Open the discharge port 16 of the regulating chamber and start the slurry pump 3 to pump the evenly dispersed fiber slurry into the filter chamber of the plate and frame filter press. Start the filter press and, according to the pre-stored "dewatering pressure-time" curve program in the PLC controller 12, maintain pressure at 0.8 MPa for 20 minutes to dewater the slurry to the target moisture content of the wet cake. During this process, the fibers are fixed in a uniformly distributed position, preventing migration and re-agglomeration, effectively maintaining their dispersed state.

[0041] Step 5: Mixing Process. After dehydration, the filter cake falls into the cake collection frame 27 and is then conveyed through the cake inlet 31 to the integrated crushing and mixing machine 34, where it is crushed into loose blocks with a particle size of less than 50 mm. Simultaneously, a measured amount of curing agent is added through the top curing agent inlet 32, and an appropriate amount of water is added through the water inlet 33 to adjust the final moisture content. The mixture is stirred at 35 rpm for 4 minutes, with the two mixing shafts rotating in opposite directions, applying strong compression, shearing, and convection to the mixture, ensuring that the curing agent, water, and fiber-reinforced soil reach a highly uniform mixing state in a short time.

[0042] Step 6: Finished Product Output Stage. The final, uniformly mixed finished fiber-reinforced soil is discharged from the fiber-reinforced soil outlet 35, and can be directly loaded onto a truck or proceed to the next molding process.

[0043] The scope of protection of this utility model is not limited to the specific values ​​described in the above embodiments. Any process that utilizes the working principle of this utility model, namely, adjusting the slurry density to approximately the fiber density to achieve semi-suspended and efficient dispersion of fibers, followed by dehydration and mixing with a curing agent, and the equipment used to achieve this process, should be considered to fall within the scope of protection of this utility model.

Claims

1. A device for preparing fiber-stabilized soil based on density adjustment and semi-suspension dispersion, characterized in that, It includes a density adjustment and fiber dispersion system, a dewatering system, and a mixing system arranged sequentially according to the material conveying direction; The density adjustment and fiber dispersion system includes a density adjustment chamber and a support device. The top of the density adjustment chamber is equipped with a slurry conveying port and a fiber feeding port, and the side wall is equipped with a water inlet valve. The chamber is equipped with a stirring device and an online density meter, and the bottom is equipped with a discharge port. The online density meter is connected to a PLC controller, and the PLC controller is connected to the water inlet valve. The PLC controller receives the signal from the online density meter and controls the opening and closing of the water inlet valve. The density adjustment chamber is connected to the dewatering system through a slurry pump. After the fiber slurry is processed into slurry cake by the dewatering system, it is sent to the mixing system to mix with the curing agent.

2. The fiber-stabilized soil preparation device based on density adjustment and semi-suspension dispersion according to claim 1, characterized in that, The target density range preset in the PLC controller is set based on the density of the input fiber, and the target density value is between 1.01 times and 1.10 times the fiber density.

3. The fiber-stabilized soil preparation device based on density adjustment and semi-suspension dispersion according to claim 1, characterized in that, The stirring device includes a stirring shaft located at the center and six stirring blades symmetrically distributed on the stirring shaft. The stirring blades have a spiral structure, and the connecting shaft of the stirring blades is detachably connected to the stirring shaft. A scraper is connected to one end of the connecting shaft near the inner wall of the density adjustment chamber.

4. The fiber-stabilized soil preparation device based on density adjustment and semi-suspension dispersion according to claim 1, characterized in that, The dewatering system is a plate and frame filter press.

5. The fiber-stabilized soil preparation device based on density adjustment and semi-suspension dispersion according to claim 1, characterized in that, The mixing system is a twin-shaft forced mixer with a curing agent inlet and a water inlet at the top.

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