Superfine particle soil fluid solidification agent and intelligent piling process

Abstract

This invention discloses an ultrafine particle soil fluidized solidifier and an intelligent pile-forming process for in-situ pre-mixed fluidized solidified soil. The solidifier comprises cement, granulated blast furnace slag powder, and other main solidifying materials, along with an organic polymeric dispersant. Through the action of a low dosage of the organic polymeric dispersant, the plastic-to-fluid transition of the cohesive solidified soil is achieved, solving the technological challenges in preparing ultrafine particle fluidized solidified materials with high dosage, low moisture content, and high strength. An innovative airtight construction process is proposed. By introducing a pressurized airflow during mixing, the gas phase space of the ultrafine particle fluidized solidified material is increased, providing space for the growth of hydration product crystals and suppressing the strength-reducing effect of the organic polymeric dispersant on the solidified soil. This achieves rapid mixing of the solidifying material and the solidified soil, significantly improving the construction efficiency of in-situ soil solidification.

Description

Technical Field

[0001] This invention belongs to the field of ultrafine particle cohesive soft soil foundation treatment technology, specifically involving an ultrafine particle soil fluid solidifier and intelligent pile forming process, including an ultrafine particle soil material high-efficiency fluid solidifier, rotary soil cutting, mixing and spraying, and real-time monitoring of the mixing and pile forming construction process. It is mainly used for foundation reinforcement in soft soil areas with ultrafine particle soil materials such as silty cohesive soil and collapsible loess, replacing some of the existing cement-soil mixing pile and pile foundation construction processes. Background Technology

[0002] Ultrafine-grained soil materials include cohesive waste soil, phosphogypsum, tailings, fly ash, and other materials with a main particle size reaching the clay particle level, which are formed in engineering construction such as transportation, civil engineering, mining, and river channels, as well as undisturbed materials of saturated cohesive soft soil foundations. Their multi-source heterogeneous and complex structural characteristics pose new challenges to the applicability of ex-situ and in-situ construction technologies for solidification projects.

[0003] Existing research indicates that for unsaturated cohesive waste soil with a clay content greater than 25%, obtaining an ultrafine-particle fluidized solidification material with a flowability greater than 160 mm and a 28-day unconfined compressive strength greater than 0.8 MPa is extremely difficult when the cement-based solidifier content is greater than 16% and the water content is less than 100%. To achieve a flowability of 160 mm in cohesive solidified soil, its free water content generally cannot be lower than 160%, and the cement-based solidifier content should generally be less than 10%. This type of ultrafine-particle fluidized solidification material typically has a 28-day unconfined compressive strength less than 0.5 MPa, limiting its application range to soil amendment rather than structural layers with specific functions.

[0004] Clayey soils are primarily composed of clay particles. These particles cannot overcome the van der Waals forces between molecules, resulting in an aggregated microstructure. Increasing the free water content of the clayey soil to a supersaturated state allows for the filling of spaces between clay particles with a large amount of free water, reducing the constraint of molecular van der Waals forces on particle behavior and giving it a certain degree of fluidity. Cement-based solidifiers, however, consume some free water during hydration, increasing the constraint of molecular van der Waals forces on clay particle behavior and reducing the fluidity of the clayey soil. Therefore, the amount of solidifier added must be controlled. The amount of solidifier added and its degree of hydration directly affect the 28-day strength of the solidified clayey soil. In a non-flowing state, the 28-day strength of solidified clayey soil reaches 0.8 MPa, and the cement-based solidifier content should generally not be less than 16%. In a flowing state, to achieve a 28-day strength of 0.8 MPa, the solidifier content should be at least 16%. Therefore, the contradiction between the fluidity and strength at maturity of cohesive solidified soil is a key technical challenge in the preparation process of ultrafine particle fluidized solidified materials with high admixture (above 16%), low water content (below 100%), and high strength (above 0.8MPa).

[0005] Furthermore, given the lack of real-time and effective construction quality monitoring technologies and methods for cement-soil multi-directional mixing pile technology, and the current situation where existing practical projects cannot guarantee construction quality through real-time monitoring of cement mixing pile construction parameters, there is an urgent need to develop an intelligent pile data acquisition and analysis system. Summary of the Invention

[0006] This invention aims to solve the following technical problems: to solve the preparation process difficulties of ultrafine particle fluidized solidification materials with high dosage, low water content, and high strength, and to realize the plastic-fluid transition of cohesive solidified soil; to overcome the reduction effect of organic polymer dispersants on the strength of solidified soil over time, and to achieve a coordinated unity of fluidity and strength; and to provide an intelligent pile data acquisition and analysis system based on wireless Internet of Things technology to realize real-time monitoring and quality control of cement mixing pile construction parameters.

[0007] To achieve the above objectives, this invention provides a preparation process for a highly efficient fluidized solidifying agent for ultrafine particle soil materials. The solidifying agent comprises, by weight percentage, cement, slag powder, an alkaline activator, and an organic polymeric dispersant, mixed uniformly to form a solidifying agent powder. The solidifying agent powder comprises, by weight percentage, two groups: a first solidifying agent or a second solidifying agent. The first curing agent powder consists of 45%~60% cement, 40%~55% slag powder, 4.5%~15% alkaline activator (based on the combined amount of cement and slag powder), and 0.1%~0.9% organic polymeric dispersant (based on the combined amount of cement and slag powder). The first curing agent is used for in-situ or ex-situ curing of ultrafine-particle soil materials such as silty clay and collapsible loess. When used for in-situ / ex-situ curing, the construction method is mainly mixing, without the need for pumping, grouting, or self-compacting. The fluidity requirement is low; only uniform mixing of the curing agent and soil is needed. Therefore, high-volume dispersant is not required to provide flow transition capability. Although the soils requiring in-situ / ex-situ curing, such as collapsible loess and ordinary silty clay, are ultrafine particles, their clay aggregate strength is lower compared to marine high-organic-matter silt. A small amount of dispersant is sufficient to achieve adequate dispersion of cement and slag powder with the soil, avoiding a decrease in the stability of the curing system due to excessive dispersant.

[0008] The second curing agent powder consists of 45%–60% cement, 40%–55% slag powder, 4.5%–15% alkaline activator (based on the combined amount of cement and slag powder), and 0.91%–1.6% organic polymeric dispersant (based on the combined amount of cement and slag powder). The second curing agent is used in in-situ pre-mixed fluidized solidified soil for cast-in-place pile construction. Cast-in-place pile construction requires highly fluid solidified soil to be pumped into the pile hole and self-compacted, preventing defects such as voids and cracks in the pile body. For ultrafine-particle soil materials, such as high-organic-matter marine silt, under conditions of low water content and high curing agent dosage, the clay aggregates have extremely strong van der Waals forces, requiring a high dosage of dispersant to break down the aggregates, release bound water, achieve a plastic-to-fluid transition, and meet the requirements for pumping and self-compacting. Cast-in-place pile construction often faces complex soils with high organic matter and high clay content. These soils have denser clay aggregates and higher bound water content, making it difficult for low-dosage dispersants to effectively break down the aggregate structure. High-dosage dispersants (up to 1.6%) can enhance electrostatic repulsion through the double-layer effect and prevent clay re-agglomeration through steric hindrance, ensuring stable fluidity of the solidified soil during grouting. While excessive dispersant can lead to strength loss, the second solidifying agent compensates for this loss through an airtight preparation process, providing ample space for hydration product growth. The fluidity requirements resulting from high-dosage dispersants, combined with high-pressure airflow reinforcement, synergistically satisfy construction fluidity needs while ensuring high-age strength through sufficient hydration product growth.

[0009] Furthermore, the cement is PO 42.5 silicate cement or ordinary silicate cement; the slag powder is S95 granulated blast furnace slag powder; the alkaline activator includes gypsum, sodium hexametaphosphate and calcium carbonate, wherein the amount of gypsum is 4% to 12% of the sum of the amounts of cement and slag powder, the amount of sodium hexametaphosphate is 0.1% to 0.5%, and the amount of calcium carbonate is 0.5% to 2.5%.

[0010] Furthermore, the organic polymeric dispersant is a polycarboxylate-based high-performance water-reducing agent, model U-6, whose main components are sodium salt and acrylic homopolymer, containing carboxylate-COO groups. - It exhibits excellent stability in both acidic and alkaline solutions. The organic polymeric dispersant adsorbs onto the surface of soil particles, causing the particle surfaces to carry the same charge. Through electrostatic repulsion and the steric hindrance effect of the polymer chains in the organic polymeric dispersant, the van der Waals forces between particles are balanced, weakening the edge-to-edge or edge-to-face forces between particles. This leads to particle agglomeration and disintegration, destroying the original flocculation structure, improving particle dispersibility, and converting the crystal water encapsulated in the flocs into free water, thereby enhancing the fluidity of the slurry. The carboxylate group -COO in the molecular structure... - Able to complex with some free Ca 2+ Al 3+The presence of metal cations reduces the concentration of active ions in the solution, resulting in a more uniform distribution of soil particles and an increase in free water. However, during the process of particle agglomeration and disintegration, the gas trapped inside the particles will escape, leading to a reduction in the gas phase space inside the sample. This makes the internal space more compact, but it also limits the growth space of hydration product crystals and inhibits the increase in the strength of the fluidized solidified soil.

[0011] Organic polymeric dispersants achieve high fluidity and self-compacting properties in viscous fluidized solidified soils by altering the distribution and growth state of the solid-liquid-gas phases within the soil, but also limit its strength growth to some extent. Therefore, during the preparation and mixing process of airtight fluidized solidified soils, a high-pressure airflow needs to be continuously pumped into the soil to compensate for air loss caused by the disintegration of clay aggregates under the action of the dispersant, thereby improving the gas phase space and compactness of the fluidized solidified soil.

[0012] On the other hand, the present invention also provides an application of the first curing agent as described above, in which cement, slag powder and alkaline activator are fully dispersed and applied to in-situ or ex-situ curing of ultrafine-particle soil materials such as silty clay and collapsible loess.

[0013] On the other hand, the present invention also provides an application of the second curing agent as described above. By using the second curing agent, the plastic-fluid transformation of fine-grained materials under low moisture content conditions is realized, forming a fluidized solidified soil with high strength at maturity, high fluidity, and high airtightness. This is applied to in-situ premixed fluidized solidified soil cast-in-place pile operations. The moisture content is defined as the percentage of the mass of all water in the solidified soil to the total mass of the solidified soil. A low moisture content is defined as a moisture content of less than 80% of the solidified soil.

[0014] Furthermore, the preparation of the airtight fluidized solidified soil includes continuously pumping a high-pressure airflow into the solidified soil during the mixing process, with a flow rate of 0.2-0.8 m / s, to compensate for the air release loss caused by the disintegration of clay aggregates under the action of the dispersant, thereby improving the gas phase space and density of the fluidized solidified soil.

[0015] This invention also provides an intelligent pile-forming process for in-situ premixed fluidized solidified soil, based on the aforementioned second solidifying agent, comprising the following steps: Step 1: Intelligent batching and mixing. An intelligent pile-forming data acquisition and analysis system enables automatic batching and mixing, with real-time monitoring of flowability until it reaches 160mm or more. This system includes: real-time construction parameter acquisition devices (depth sensor, weight sensor, flow sensor, BeiDou positioning module, current / energy consumption monitoring module); online monitoring and analysis software (slurry preparation backend system, construction monitoring system, mobile terminal, large display screen); and a data transmission and storage module (using wireless communication technology for real-time data transmission and cloud storage). This intelligent pile-forming data acquisition and analysis system is a full-process construction quality monitoring system based on the Internet of Things and a cloud platform. The specific functions and collaborative methods of its components are as follows: (I) Specific functions of each component Depth sensor: Installed on the mixing drill rod, it monitors the drilling depth and lifting height of the drill rod in real time with an accuracy of ±0.01m, ensuring that the pile length meets the design requirements.

[0016] Weight sensor: The weighing module installed in the hardener powder tank and water tank monitors the consumption of hardener and water in real time, calculates the amount of powder sprayed per unit depth (kg / m) and the water-cement ratio, and prevents insufficient hardener dosage.

[0017] Flow sensor: Installed in the slurry delivery pipeline to monitor the slurry flow rate (L / min) in real time, and to determine whether the pipeline is blocked or leaking in conjunction with the pumping pressure.

[0018] Beidou positioning module: Installed on the top of the pile driver, it obtains the latitude and longitude coordinates of the pile position in real time, realizes accurate pile position positioning and construction trajectory recording, and avoids missing piles or repeated pile driving.

[0019] Current / energy consumption monitoring module: monitors the current and power of the mixing motor and pumping motor, reflects changes in mixing resistance, and indirectly judges the uniformity of soil and the fluidity of solidified soil.

[0020] Online monitoring and analysis software: The pulping back-end system receives sensor data and automatically calculates key parameters such as curing agent dosage, water-cement ratio, and fluidity. When the set threshold is exceeded, it automatically alarms and adjusts the batching ratio.

[0021] Construction monitoring system: Displays construction parameters in real time using digital instruments, graphs, pile location maps, etc., for on-site operators and managers to monitor.

[0022] Mobile terminals: Project managers or supervisors can remotely view construction progress and quality data and receive abnormal alerts via a mobile app.

[0023] Large display screen: Used for centralized monitoring by the project department, displaying data from multiple piling machines on the same screen for easy unified scheduling.

[0024] Data transmission and storage module: Using 4G / 5G or Wi-Fi wireless communication, the collected data is uploaded to the cloud server every second to ensure the real-time nature and immutability of the data; the cloud storage is for no less than 5 years, supporting historical data traceability and statistical analysis.

[0025] The process of intelligent pile formation is achieved through the coordinated operation of various components. Taking the construction of in-situ premixed fluidized solidified soil cast-in-place piles as an example, the collaborative workflow of the system is as follows: Pre-construction settings: Input parameters such as design pile length, curing agent dosage, water-cement ratio, and fluidity target through the construction monitoring system.

[0026] Drilling process monitoring: The Beidou positioning module confirmed that the pile location was correct.

[0027] The depth sensor records the drilling depth in real time, and the current / energy consumption monitoring module monitors the stirring current. If the current suddenly increases, the system prompts to reduce the drilling speed.

[0028] The pulping back-end system automatically adjusts the water valve opening and the speed of the curing agent screw feeder based on data from flow and weight sensors to ensure a stable water-cement ratio.

[0029] Ingredient preparation and mixing process control: The weight sensor accumulates the amount of curing agent and water used, and automatically stops feeding when the design value is reached.

[0030] The flowability tester, either online or offline, transmits the flowability value to the pulping backend system. If the flowability is <160mm, the system instructs to add a trace amount of water or dispersant; if it is >220mm, the water is reduced.

[0031] The flow rate of the high-pressure airflow is monitored by a flow sensor, and the pulping back-end system automatically adjusts the air compressor output according to the dispersant dosage to ensure sufficient gas phase space.

[0032] Monitoring of the lifting and grouting process: Depth sensors monitor the drill rod lifting speed, and the slurry preparation system synchronously controls the powder spraying and slurry spraying valves to ensure uniform curing agent dosage per meter.

[0033] The flow sensor provides real-time feedback on the slurry flow rate. If the flow rate fluctuates by more than ±10%, the system will automatically alarm and prompt for pipeline inspection.

[0034] The current / energy consumption monitoring module records the energy consumption of the mixing process and generates an energy consumption curve per meter based on the depth data, which is used to determine the uniformity of the pile strength afterward.

[0035] Data Upload and Alerts: All data is uploaded to the cloud every second via a wireless communication module, and the online monitoring and analysis software compares the design and actual values ​​in real time.

[0036] If the threshold is exceeded, such as when the powder spraying amount deviation is greater than 5%, the construction monitoring system will pop up a red warning, and at the same time, the mobile terminal will push alarm information to the supervisor.

[0037] After construction is completed, the cloud automatically generates a pile quality report, including depth-powder spraying volume curve, depth-current curve, pile location coordinate diagram, etc., which supports comparative analysis during core sampling inspection.

[0038] Step 2: Preparation of airtight fluidized solidified soil. After the required fluidity is achieved, a high-pressure airflow is continuously pumped in. During the mixing process, a high-pressure airflow is continuously pumped into the solidified soil to effectively compensate for the air loss caused by the disintegration of clay aggregates under the action of the dispersant. This significantly improves the gas phase space and density of the fluidized solidified soil, providing sufficient geometric space for the generation of hydration products and crystal growth in the solidification system. The high-pressure airflow is introduced when the solidified soil begins to exhibit fluidity after the organic polymeric dispersant is added and initially dispersed, and the pressurized airflow continues until the injection is complete.

[0039] Step 3: Intelligent grouting and pile formation, using an intelligent pile formation data acquisition and analysis system to monitor parameters such as construction depth, powder spraying volume per unit depth, grout flow rate, and pile verticality in real time; Step 4: Quality inspection and acceptance. Fiber optic grating sensors are used to measure the stress distribution in the pile body, and online monitoring and analysis software is used to automatically collect, analyze, and issue early warnings for construction parameters.

[0040] Furthermore, the intelligent pile driving data acquisition and analysis system includes: Real-time construction parameter acquisition device: depth sensor, weight sensor, flow sensor, Beidou positioning module, current / energy consumption monitoring module; Online monitoring and analysis software: pulp preparation back-end system, construction monitoring system, mobile terminal, display screen; Data transmission and storage module: Employs wireless communication technology to achieve real-time data transmission and cloud storage.

[0041] Furthermore, the timing of the high-pressure airflow is as follows: after the organic polymer dispersant is added and initially dispersed, when the solidified soil begins to exhibit flow characteristics, the pressurized airflow is continuously introduced until the grouting is completed.

[0042] This invention also provides an intelligent pile-forming process for in-situ pre-mixed solidified soil, based on the aforementioned first solidifying agent, comprising the following steps: Step 1: Pretreatment of undisturbed soil. Crush and screen ultrafine soil materials such as silty clay and collapsible loess, control the particle size to ≤2mm, and adjust the moisture content to 35%~45% to ensure full contact between the soil and the solidifying agent. Step 2: Intelligent batching and mixing. The amount of the first curing agent powder and the pretreated original soil are accurately measured by the intelligent pile data acquisition and analysis system. The batching is carried out automatically according to the mass ratio of curing agent to original soil of 12%~18%. Water is added and stirred. The water-cement ratio is controlled at 0.55~0.7. The stirring speed is 50~70 r / min. Stirring is continued for 4~6 minutes to fully disperse the main curing agent cement, slag powder and alkaline activator to form a uniform cured soil material. Step 3: Intelligent pile construction. Multi-directional mixing pile equipment is used for in-situ pre-mixing. A smart pile data acquisition and analysis system monitors key parameters in real time, including construction depth, powder spraying volume per unit depth, mixing speed, and pile verticality. The solidified soil material is compacted through in-situ mixing and extrusion to form piles. The smart pile data acquisition and analysis system includes a real-time construction parameter acquisition device, online monitoring and analysis software, and a data transmission and storage module. The real-time construction parameter acquisition device consists of a depth sensor, a weight sensor, a flow sensor, a Beidou positioning module, and a current / energy consumption monitoring module, which are used to monitor drilling depth, curing agent dosage, slurry flow rate, pile location coordinates, and mixing energy consumption, respectively. The online monitoring and analysis software includes a pulping backend system and a construction monitoring system, which are used to receive sensor data, automatically calculate key parameters, alarm when thresholds are exceeded, and adjust the batching ratio. The data transmission and storage module uses wireless communication technology to upload the collected data to the cloud in real time, supporting historical data tracing and construction quality report generation. Step 4: Curing and quality inspection. After pile formation, the piles are cured under standard curing conditions for 14-60 days. The stress distribution of the pile body is measured using fiber optic grating sensors. Quality inspection is carried out in combination with unconfined compressive strength test and electron microscopy scanning test. Online monitoring and analysis software is used to realize the automatic collection, storage, archiving and early warning analysis of construction parameters and test data.

[0043] The beneficial effects of this invention are: By employing a low-dosage organic polymeric dispersant, the plastic-to-fluid transition of cohesive solidified soil was achieved, significantly improving the fluidity of cohesive soft soil, reducing setting time, and enabling grouting of cohesive soft soil under low moisture content conditions. Through an airtight construction process, pressurized airflow is introduced during mixing to increase the gas phase space of the ultrafine particle fluidized solidified material, providing space for the growth of hydration product crystals, inhibiting the strength reduction effect of the organic polymeric dispersant on the solidified soil, and resolving the contradiction between the fluidity and age-appropriate strength of cohesive solidified soil. Based on the concept of fluidized solidified soil, the intelligent construction process of airtight multi-directional cement-soil mixing piles replaces the traditional mixing process that increases the number of soil cuts per unit time with an innovative mode of injecting high-pressure airflow, enhancing the fluidity of the solidified soil, achieving rapid mixing of the solidified slurry and soil, and improving construction efficiency. An intelligent pile data acquisition and analysis system based on wireless IoT technology was developed, which can monitor the construction progress and quality of mixing piles in real time, improving the convenience and accuracy of quality control in deep mixing methods, and solving the problem of not being able to monitor and record quality defects in underground cement pile grouting construction in the past. Meanwhile, the fluidized solidified soil prepared by this invention has excellent airtightness and impermeability, and is particularly suitable for underground engineering projects with high requirements for water stoppage. It uses industrial waste as the main component of the solidification material, reduces the amount of cement used, realizes the resource utilization of waste materials, and has significant economic, social and environmental benefits. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0045] I. Experimental Materials and Basic Parameters 1. Raw materials Undiscovered soil: Two types of typical ultrafine particle soil were selected: silty clay soil with a moisture content of 40%, an organic matter content of 8%, and a particle size of ≤2mm; and marine silty soft soil with a moisture content of 42%, an organic matter content of 12%, and a particle size of ≤2mm. Main solidifying materials: P.O42.5 ordinary Portland cement, S95 granulated blast furnace slag, with a specific surface area of ​​414 m². 2 / kg; Alkaline activators: gypsum (CaSO4·2H2O), sodium hexametaphosphate (98% purity), calcium carbonate (99% purity); Organic polymeric dispersant: The main components are sodium salt and acrylic acid homopolymer, containing carboxylate group -COO. - The effective content is 48%. Water: Tap water, conforming to the "Standard for Water Used in Concrete".

[0046] 2. Basic Experimental Conditions Maintenance conditions: Standard maintenance, temperature controlled at 20℃±3℃, humidity controlled at 90% RH; Test methods: Flowability was tested using the φ80mm acrylic cylinder method; unconfined compressive strength was tested using 70.7mm×70.7mm×70.7mm test blocks, which were cured for 14d, 28d, and 60d respectively; setting time was tested using the Vicat apparatus method. Intelligent construction parameters: construction depth monitoring accuracy ±0.01m, powder spraying amount monitoring accuracy ±0.1kg / m, mixing speed 50~80r / min.

[0047] II. Implementation Plan Design Example 1: First curing agent and in-situ curing process 1. Formula (by weight percentage) Main curing agent: 50% cement, 50% S95 slag powder; Alkaline activators: gypsum (6% of the total mass of cement and slag), sodium hexametaphosphate (0.3% of the total mass of cement and slag), and calcium carbonate (1.5% of the total mass of cement and slag); Organic polymeric dispersant: specifically U-6 type polycarboxylate dispersant, purchased from Shenzhen Miaojie Cleaning Agent Co., Ltd., accounting for 0.6% of the total mass of cement and slag; The mass ratio of curing agent to undisturbed soil is 15%, and the water-cement ratio is 0.6.

[0048] 2. Construction process Pretreatment of undisturbed soil: crush and screen to a particle size ≤2mm, adjust the moisture content to 40%; Intelligent batching and mixing: planetary mixer at 60 r / min for 5 minutes; Intelligent pile formation: In-situ pre-mixing of multi-directional mixing piles, with real-time monitoring of parameters such as construction depth and powder spraying volume; Maintenance: Standard maintenance for 14 days, 28 days, and 60 days.

[0049] 3. Experimental Data Table 1 Performance Indicators of Example 1

[0050] Example 2: Second curing agent and cast-in-place pile process 1. Formula (by weight percentage) Main curing agent: 55% cement, 45% S95 slag powder; Alkaline activators: 8% of the total mass of cement and slag (given by weight), 0.4% of the total mass of cement and slag (given by weight), and 1.5% of the total mass of cement and slag (given by weight). Organic polymeric dispersant: specifically U-6 type polycarboxylate dispersant, purchased from Shenzhen Miaojie Cleaning Agent Co., Ltd., accounting for 1.2% of the total mass of cement and slag; The ratio of curing agent to undisturbed soil is 20%, and the water-cement ratio is 0.55.

[0051] 2. Construction process Pretreatment of undisturbed soil: crush and screen to a particle size ≤2mm, adjust the moisture content to 35%; Intelligent batching and mixing: The planetary mixer is used for mixing at a speed of 70 r / min for 4 minutes. After the fluidity meets the standard (≥160 mm), a high-pressure airflow of 0.5 m / s is introduced. Intelligent grouting pile formation: pump grouting with real-time monitoring of construction depth, grout flow rate, and pile verticality; Maintenance: Standard maintenance for 14 days, 28 days, and 60 days.

[0052] 3. Experimental Data Table 2 Performance Indicators of Example 2

[0053] Example 3: Optimized Formulation of Second Curing Agent 1. Formula (by weight percentage) Main curing agent: 60% cement, 40% S95 slag powder; Alkaline activator: 10% of the total mass of cement and slag (given by weight), 0.5% of the total mass of cement and slag (given by weight), and 2.0% of the total mass of cement and slag (given by weight). Organic polymeric dispersant: specifically U-6 type polycarboxylate dispersant, purchased from Shenzhen Miaojie Cleaning Agent Co., Ltd., accounting for 1.5% of the total mass of cement and slag; The mass ratio of curing agent to undisturbed soil is 22%, and the water-cement ratio is 0.5.

[0054] 2. The construction process is the same as in Example 2.

[0055] 3. Experimental Data Table 3 Performance Indicators of Example 3

[0056] Comparative Example 1: Low Dispersant Dosage of First Curing Agent 1. Formula Same as Example 1, except that the amount of organic polymeric dispersant was changed to 0.05%; The remaining parameters and processes are the same as in Example 1.

[0057] 2. Experimental Data Table 4 Performance Indicators of Comparative Example 1

[0058] Comparative Example 2: Second Curing Agent with Low Dispersant Dosage 1. Formula Same as Example 2, except that the amount of organic polymeric dispersant was changed to 0.7%; The remaining parameters and processes are the same as in Example 2.

[0059] 2. Experimental Data Table 5 Performance Indicators of Comparative Example 2

[0060] Comparative Example 3: Second curing agent without high-pressure airflow 1. Formulation and Process Same as Example 2, except that the high-pressure airflow during the stirring process is eliminated; The remaining parameters and processes are the same as in Example 2.

[0061] 2. Experimental Data Table 6 Performance Indicators of Comparative Example 3

[0062] Comparative Example 4: Traditional Cement Hardener 1. Formulation and Process Hardener: Pure P.O42.5 cement, dosage 25%, industry standard dosage; Process: Traditional cement-soil mixing pile process, without intelligent monitoring, dispersant, or high-pressure airflow; Untouched soil: Same as in Example 2.

[0063] 2. Experimental Data Table 7 Performance Indicators of Comparative Example 4

[0064] Comparative Example 5: No alkaline activator 1. Formula Similar to Example 2, except that the alkaline activator was removed; the remaining parameters and processes are the same as in Example 2.

[0065] 2. Experimental Data Table 8 Performance Indicators of Comparative Example 5

[0066] III. Experimental Data Analysis Based on the experimental data above, we can see that in the first curing agent scenario, the dispersant in Example 1 is 0.6%, the fluidity is 85 mm, which meets the requirements for in-situ mixing uniformity, and the 28-day strength is 2.5 MPa; the dispersant in Comparative Example 1 is 0.05%, the fluidity is only 30 mm, the clay agglomerates are not dispersed, and the strength decreases by 28%. This shows that low dosage of dispersant can meet the dispersion requirements of ordinary curing, and excessive dosage is unnecessary and avoids strength loss.

[0067] In the second curing agent scenario, the dispersant in Example 2 was 1.2%, the fluidity was 180 mm, which met the pumping requirements, and the 28-day strength was 3.8 MPa; in Comparative Example 2, the dispersant was 0.7%, the fluidity was 110 mm, it could not be pumped, the pile integrity was poor, and the strength decreased by 42.1%, indicating that high dosage of dispersant is the key to achieving plastic-fluid transition.

[0068] Example 2 contains an activator, and the strength is 3.8 MPa after 28 days. In Comparative Example 5, which does not contain an activator, the strength is 2.5 MPa, a decrease of 34.2%, and the setting time is extended by 25%. This indicates that gypsum promotes the formation of ettringite, sodium hexametaphosphate activates the activity of slag, and calcium carbonate strengthens particle coagulation. The three factors work synergistically to improve the strength and setting stability.

[0069] In Example 2, the composite material using cement slag had a 28-day strength of 3.8 MPa, while in Comparative Example 4, the pure cement with curing agent had a strength of 1.2 MPa. This indicates that the slag reacts with the cement hydration products to produce more CSH gel, and reduces the amount of cement used, making it a green and environmentally friendly solution.

[0070] Example 2 contained a high-pressure gas flow, with an intensity of 3.8 MPa after 28 days. Comparative Example 3 did not contain a high-pressure gas flow, and its intensity was 2.9 MPa, a decrease of 23.7%. Electron microscopy showed that the former had lower porosity and more uniform distribution of hydration products, indicating that the high-pressure gas flow compensated for the loss of gas phase space and coordinated the contradiction between fluidity and intensity.

[0071] The first curing agent is suitable for in-situ curing of silty clayey soil. In Example 1, the 60-day strength is 3.2 MPa, which meets the requirements for shallow treatment of roadbed and foundation. The second curing agent is suitable for marine silt cast-in-place piles. In Example 2, the 28-day strength is 3.8 MPa and the pile body is intact, solving the problem of pile formation in traditional processes. In Example 3, for marine silt with high organic matter, the strength still reaches 3.6 MPa, demonstrating broad-spectrum compatibility.

[0072] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A superfine particle soil fluidizing agent, characterized in that, The curing agent is a powder, which is uniformly mixed from cement, slag powder, alkaline activator, and organic polymer dispersant according to a set weight percentage; the curing agent includes a first curing agent or a second curing agent: The first curing agent powder, by weight percentage, consists of: 45%~60% cement, 40%~55% slag powder, 4.5%~15% alkaline activator (based on the sum of cement and slag powder usage), and 0.1%~0.9% organic polymer dispersant (based on the sum of cement and slag powder usage). The second curing agent powder, by weight percentage, consists of: 45%~60% cement, 40%~55% slag powder, 4.5%~15% alkaline activator (based on the sum of cement and slag powder usage), and 0.91%~1.6% organic polymer dispersant (based on the sum of cement and slag powder usage).

2. The ultrafine particle soil fluidizing agent according to claim 1, characterized in that, The cement is PO 42.5 silicate cement or ordinary silicate cement; the slag powder is S95 granulated blast furnace slag powder; the alkaline activator includes gypsum, sodium hexametaphosphate and calcium carbonate, wherein the amount of gypsum is 4% to 12% of the sum of the amounts of cement and slag powder, the amount of sodium hexametaphosphate is 0.1% to 0.5%, and the amount of calcium carbonate is 0.5% to 2.5%.

3. The ultrafine particle soil fluidizing agent according to claim 1, characterized in that, The organic polymeric dispersant is mainly composed of sodium salt and acrylic acid homopolymer, containing carboxyl groups, and has excellent stability in both acidic and alkaline solutions.

4. An application of the first curing agent as claimed in claim 1, characterized in that, The first curing agent is used to fully disperse cement, slag powder and alkaline activator, and is applied to the in-situ or ex-situ curing of ultrafine-particle soil materials such as silty clay and collapsible loess.

5. An application of the second curing agent as claimed in claim 1, characterized in that, The second curing agent is used to achieve the plastic-fluid transformation of fine-grained materials under low moisture content conditions, forming a fluidized solidified soil with high strength at maturity, high fluidity, and high airtightness. It is applied to in-situ premixed fluidized solidified soil grouting pile operations. The moisture content is defined as the percentage of the mass of all water in the solidified soil to the total mass of the solidified soil. The low moisture content is defined as the moisture content of the solidified soil being less than 80%.

6. The application according to claim 5, characterized in that, The preparation of the fluidized solidified soil includes: continuously pumping high-pressure airflow into the solidified soil during the mixing process, with an airflow velocity of 0.2-0.8 m / s, to compensate for the air release loss caused by the disintegration of clay aggregates due to the action of dispersant, and to improve the gas phase space and density of the fluidized solidified soil.

7. An intelligent pile-forming process for in-situ premixed fluidized solidified soil, based on the second curing agent described in claim 1, characterized in that, Includes the following steps: Step 1: Intelligent batching and mixing. The intelligent pile data acquisition and analysis system enables automatic batching and mixing, and real-time monitoring of flowability until it reaches more than 160mm. Step 2: Preparation of airtight fluidized solidified soil; after the fluidity meets the requirements, high-pressure airflow is continuously pumped. Step 3: Intelligent grouting and pile formation, using an intelligent pile formation data acquisition and analysis system to monitor parameters such as construction depth, powder spraying volume per unit depth, grout flow rate, and pile verticality in real time; Step 4: Quality inspection and acceptance. Fiber optic grating sensors are used to measure the stress distribution in the pile body, and online monitoring and analysis software is used to automatically collect, analyze, and issue early warnings for construction parameters.

8. The intelligent pile-forming process according to claim 7, characterized in that, The intelligent pile driving data acquisition and analysis system includes: Real-time construction parameter acquisition device: depth sensor, weight sensor, flow sensor, Beidou positioning module, current / energy consumption monitoring module; Online monitoring and analysis software: pulp preparation back-end system, construction monitoring system, mobile terminal, display screen; Data transmission and storage module: Employs wireless communication technology to achieve real-time data transmission and cloud storage.

9. The intelligent pile-forming process according to claim 7, characterized in that, The timing of the high-pressure airflow is as follows: after the organic polymer dispersant is added and initially dispersed, when the solidified soil begins to exhibit flow characteristics, the pressurized airflow is continuously introduced until the grouting is completed.

10. An intelligent pile-forming process for in-situ pre-mixed solidified soil, based on the first curing agent as described in claim 1, characterized in that, Includes the following steps: Step 1: Pretreatment of undisturbed soil. For ultrafine-particle soil materials such as silty clay and collapsible loess, crush and screen them to control the particle size ≤2mm and adjust the moisture content to 35%~45% to ensure full contact between the soil and the solidifying agent. Step 2: Intelligent batching and mixing. The amount of the first curing agent powder and the pretreated original soil are accurately measured by the intelligent pile data acquisition and analysis system. The batching is carried out automatically according to the mass ratio of curing agent to original soil of 12%~18%. Water is added and stirred. The water-cement ratio is controlled at 0.55~0.

7. The stirring speed is 50~70 r / min. Stirring is continued for 4~6 minutes to fully disperse the main curing agent cement, slag powder and alkaline activator to form a uniform cured soil material. Step 3: Intelligent pile construction. Multi-directional mixing pile equipment is used for in-situ pre-mixing. The intelligent pile data acquisition and analysis system monitors key parameters such as construction depth, powder spraying amount per unit depth, mixing speed, and pile verticality in real time. The solidified soil material is mixed and compressed in-situ to form piles, achieving dense molding. Step 4: Curing and quality inspection. After pile formation, the piles are cured under standard curing conditions for 14-60 days. The stress distribution of the pile body is measured using fiber optic grating sensors. Quality inspection is carried out in combination with unconfined compressive strength test and electron microscopy scanning test. Online monitoring and analysis software is used to realize the automatic collection, storage, archiving and early warning analysis of construction parameters and test data.

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