A solidifying agent for deep layer compaction in soft soil foundation hole, a preparation method thereof, and a material for deep layer compaction in soft soil foundation hole and a construction method thereof

Abstract

The application discloses a curing agent for deep layer dynamic compaction in soft soil foundation hole, a preparation method of the curing agent, a material for dynamic compaction and a construction method, and belongs to the technical field of soft soil foundation treatment construction. The curing agent is composed of a silicon-aluminum source material, a calcium source material, a sulfate material, an alkaline excitation source material, an inert mineral admixture, a fiber powder and a modified composite additive, and is prepared through a three-step ball milling process. Meanwhile, the application also provides a matching material for dynamic compaction, and a layered construction method of "firstly constructing a recycled aggregate skeleton through dynamic compaction, and then permeating and pouring a curing agent slurry". Through the triple synergistic effect of hydration regulation, interface modification and structure enhancement, the application effectively compensates the shrinkage of the cementing system, and significantly improves the anti-segregation performance of the slurry and the bonding force of the aggregate interface.

Description

Technical Field

[0001] This invention relates to the field of soft soil foundation treatment construction technology, specifically to a solidifying agent for deep dynamic compaction in soft soil foundations and its preparation method, as well as materials for deep dynamic compaction in soft soil foundations and their construction methods. Background Technology

[0002] In the construction of infrastructure such as highways, railways, airports, and industrial and civil buildings, foundation treatment is a crucial step in ensuring the safety and stability of the project. However, soft soil foundations are characterized by high natural water content, large void ratio, low shear strength, high compressibility, and poor permeability. Under external loads, they are prone to significant settlement, uneven settlement, or even instability, which traditional foundation treatment methods often cannot effectively address.

[0003] Deep dynamic compaction (DDC) is a highly efficient and comprehensive foundation treatment technology, particularly suitable for reinforcing soft soil foundations. It significantly improves the bearing capacity and deformation characteristics of the foundation. DDC involves filling the borehole with layers of materials such as plain soil, lime-soil, construction waste, or concrete, and then using a high-energy hammer for deep compaction. This causes the fill material to be vertically compacted while simultaneously generating a significant lateral compaction effect on the soft soil surrounding the pile. This "high kinetic energy, over-compression, and strong compaction" effect effectively improves the density and shear strength of soft soil foundations, increasing the bearing capacity of the composite foundation to 3-9 times that of the original natural foundation, far exceeding the reinforcement effect of traditional flexible piles (such as lime-soil piles and gravel piles). Furthermore, DDC allows for deep reinforcement, with a large treatment depth and good uniformity.

[0004] However, when deep compaction in boreholes is only filled with construction waste, it is impossible to form a stable pile body to resist compression deformation. Therefore, it is usually necessary to add hydraulic materials such as cement, lime, or fly ash. However, hydraulic materials shrink during the hardening process, which can lead to fracture and affect the stability of the pile. In addition, during the grouting process, the concrete cementitious material may segregate and stratify, which will affect the stability of the pile. Furthermore, some components of construction waste, such as broken bricks, broken tiles, wood chips, and plastics, have smooth or hydrophobic surfaces, making it difficult for the concrete cementitious material to adhere firmly to these surfaces. This makes the cement interface the weakest link in the entire pile, and failure often occurs here first under stress. Summary of the Invention

[0005] To overcome the above problems, the present invention provides a solidifying agent for deep dynamic compaction in holes in soft soil foundations and its preparation method, as well as materials for deep dynamic compaction in holes in soft soil foundations and their construction methods.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a solidifying agent for deep dynamic compaction in boreholes of soft soil foundations, the raw materials of which, by weight, comprise: The mixture contains 60-80 parts of silicon-aluminum source material, 40-50 parts of calcium source material, 10-30 parts of sulfate material, 5-10 parts of alkaline activation source material, 10-20 parts of inert mineral admixture, 0.1-0.5 parts of fiber powder, and 0.05-0.08 parts of modified composite additive. The silicon-aluminum source materials include iron tailings, rice husk ash, lithium slag, and waste concrete powder. The calcium source materials include steel slag, carbide slag, and phosphate tailings; The sulfate materials include desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate; The alkaline activation source materials include red mud, magnesium slag, and white mud; The inert mineral admixture includes gold tailings, sawdust, and waste glass powder; The modified composite additive includes a first functional composite agent, a second functional composite agent, polymer powder, and cellulose ether; wherein, the first functional composite agent has a core-shell structure, with porous silica loaded with alkanolamine and sodium thiocyanate as the core, and polyacrylic acid and aluminum alkoxide layers coated on the outside of the core; the second functional composite agent includes stearate and polyether-modified siloxane.

[0007] In one or more embodiments, the mass ratio of iron tailings, rice husk ash, lithium slag and waste concrete powder in the silicon-aluminum source material is (1~2):(2~4):(0.5~1):(2~5).

[0008] In one or more embodiments, the silicon-aluminum source material contains iron tailings with a total SiO2 and Al2O3 content greater than 70%, rice husk ash with a total SiO2 and Al2O3 content greater than 85%, lithium slag with a total SiO2 and Al2O3 content greater than 80%, and waste concrete powder with a total SiO2 and Al2O3 content greater than 50%.

[0009] In one or more embodiments, the specific surface area of ​​the silicon-aluminum source material, including iron tailings, rice husk ash, lithium slag, and waste concrete powder, is greater than 350 m² / kg.

[0010] In one or more embodiments, the mass ratio of steel slag, carbide slag and phosphorus tailings in the calcium source material is (2~4):(0.5~1):(0.3~1).

[0011] In one or more embodiments, the calcium source material contains more than 40% CaO in steel slag, more than 60% CaO in carbide slag, and more than 30% CaO in phosphate tailings.

[0012] In one or more embodiments, the specific surface area of ​​the calcium source material, such as steel slag, carbide slag, and phosphate tailings, is greater than 350 m² / kg.

[0013] In one or more embodiments, the mass ratio of desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate in the sulfate material is (10~15):(1~3):(0.5~1).

[0014] In one or more embodiments, the mass ratio of red mud, magnesium slag and white mud in the alkaline activation source is (5~10):(1~3):(0.5~1).

[0015] In one or more embodiments, the pH value of the alkaline excitation source is greater than 10, and the residue on a 45 μm square-hole sieve is no greater than 20.0%.

[0016] In one or more embodiments, the alkaline activation source includes red mud from sintering process with a SiO2 content greater than 20%, magnesium slag with MgO ≥ 10%, and white mud from ammonia-alkali white mud with a CaCO3 content greater than 45%.

[0017] In one or more embodiments, the mass ratio of gold tailings, sawdust, and waste glass powder in the inert mineral admixture is (5~10):(3~5):(10~15).

[0018] In one or more embodiments, the inert mineral admixture contains gold tailings with a fineness of no more than 20.0% residue on a 45 μm square-hole sieve.

[0019] In one or more embodiments, the inert mineral admixture contains more than 75% SiO2 from gold tailings, more than 85% SiO2 and Al2O3 from sawdust, and more than 70% SiO2 from waste glass powder.

[0020] In one or more embodiments, the fiber powder has a length of 100-200 μm and a diameter of 10-20 μm; the fiber powder is selected from at least one of textile waste fiber, waste fishing net, and recycled fiber from waste wind turbine blades.

[0021] In one or more embodiments, the preparation method of the first functional compound in the modified composite admixture includes: The intermediate was obtained by immersing porous silica in a mixed solution containing alkanolamine and sodium thiocyanate and removing the solvent. A mixture of polyacrylic acid and aluminum alkoxide is loaded onto the surface of an intermediate via a fluidized bed bottom spraying process, and then dried to obtain the first functional composite agent.

[0022] Preferably, the alkanolamine includes one or more of monoethanolamine or triethanolamine.

[0023] Preferably, the molar ratio of alkanolamine to sodium thiocyanate is (7~8):(3~2).

[0024] Preferably, the total mass ratio of alkanolamine and sodium thiocyanate to silicon dioxide is (0.15~0.35):1.

[0025] Preferably, the method for removing the solvent is to evaporate the solvent at 60~80°C.

[0026] Preferably, the aluminum alkoxide includes one or more of aluminum isopropoxide, aluminum sec-butoxide, or aluminum alkoxychloride.

[0027] Preferably, in the mixture of polyacrylic acid and aluminum alkoxide, the mass ratio of polyacrylic acid to aluminum alkoxide is (4~6):1.

[0028] The solvent is an aqueous ethanol solution, preferably with a mass ratio of ethanol to water of (7~3):(3~1).

[0029] Preferably, in the mixture of polyacrylic acid and aluminum alkoxide, the mass fraction of polyacrylic acid is 10-15%.

[0030] Preferably, in the mixture of polyacrylic acid and aluminum alkoxide, the mass ratio of porous silica to polyacrylic acid is 1:(0.2~0.5).

[0031] Preferably, the process parameters for the fluidized bed bottom spraying process are: inlet air temperature of 80~100℃ and spraying rate of 5~20 mL / min.

[0032] Preferably, the drying method is as follows: drying in hot air at 55~65℃ for 5~10 minutes; then switching to cold air to cool the material.

[0033] In one or more embodiments, the preparation method of the second functional composite agent includes: ball milling stearate and polyether-modified siloxane to obtain the second functional composite agent.

[0034] Preferably, the stearate includes one or more of calcium stearate, zinc stearate, or magnesium stearate.

[0035] Preferably, the mass ratio of stearate to polyether-modified siloxane is (8-10):1.

[0036] Preferably, the ball mill rotation speed is 50~80 r / min, and the ball milling time is 5~10 min.

[0037] In one or more embodiments, the polymer powder includes one or more of ethylene-vinyl acetate-based or acrylate-based redispersible latex powders.

[0038] In one or more embodiments, the cellulose ether includes one or more of hydroxypropyl methylcellulose, hydroxyethyl methylcellulose, or hydroxyethyl cellulose.

[0039] In one or more embodiments, the mass ratio of the first functional compound agent, the second functional compound agent, the polymer powder and the cellulose ether is (5~6):(0.5~1):(2~3):1.

[0040] In one or more embodiments, the method for preparing the modified composite admixture includes ball milling a first functional composite agent, a second functional composite agent, polymer powder and cellulose ether to obtain the modified composite admixture.

[0041] Preferably, the ball mill rotation speed is 50~80 r / min, and the ball milling time is 5~10 min.

[0042] A second aspect of the present invention provides a method for preparing the solidifying agent for deep dynamic compaction in boreholes of soft soil foundations as described in the first aspect, comprising the following steps: The silicon-aluminum source material, calcium source material and inert mineral admixture were ball-milled for the first time to obtain a gelation precursor; The sulfate material and the basic activation source material are ball-milled a second time to obtain an activation mixture; The gelation precursor, activating mixture, fiber powder and modified composite additives are subjected to a third ball milling to obtain a curing agent for deep dynamic compaction in holes in soft soil foundations.

[0043] In one or more embodiments, the conditions for the first ball milling are: a rotation speed of 400~500 r / min and a ball milling time of 5~10 min.

[0044] In one or more embodiments, the conditions for the second ball milling are: a rotation speed of 300~400 r / min and a ball milling time of 3~5 min.

[0045] In one or more embodiments, the conditions for the third ball milling are: a rotation speed of 200~300 r / min and a ball milling time of 15~20 min.

[0046] A third aspect of the present invention provides a material for deep dynamic compaction in holes of soft soil foundations, comprising construction waste and a curing agent for deep dynamic compaction in holes of soft soil foundations as described in the first aspect or a curing agent for deep dynamic compaction in holes of soft soil foundations prepared by the preparation method described in the second aspect.

[0047] In one or more embodiments, the average particle size of the construction waste is 50-70 mm, and the maximum particle size is less than 100 mm.

[0048] A fourth aspect of the present invention provides a construction method for deep dynamic compaction in boreholes on soft soil foundations, comprising the following steps: (1) At the predetermined pile location in soft soil foundation, use mechanical drilling equipment to drill pile holes and lower steel sleeves of the same diameter as the drilling depth. (2) Fill the pile hole with construction waste and lift the steel sleeve to the filling height; use a rammer to compact it to form a high-density aggregate skeleton layer; then add the solidifying agent slurry for deep dynamic compaction in the pile hole of soft soil foundation. (3) Repeat the operation in step (2) to complete the compaction and grouting of the top layer of construction waste, and cover and maintain the top of the pile.

[0049] The beneficial effects of this invention are as follows: This invention addresses the core problems in existing deep dynamic compaction technology, such as hardening shrinkage cracking of cementitious materials, easy segregation and stratification of slurry, weak interfacial bonding with construction waste aggregates, insufficient pile stability, and low utilization rate of industrial solid waste resources. Through component synergistic design, process optimization, and mechanism innovation, it achieves a triple improvement in curing agent performance, construction effect, and environmental benefits.

[0050] (1) In terms of improving the strength and shrinkage resistance of the curing agent, this invention forms a full-process control mechanism of "hydration activation - shrinkage compensation - interface modification - slurry stabilization" through the precise ratio and synergistic effect of silicon-aluminum source materials, calcium source materials, sulfate materials, alkaline activation source materials, fiber powder and modified composite additives, thus overcoming the performance shortcomings of traditional curing agents. Specifically, sulfate materials (desulfurized gypsum, anhydrous sodium silicate, sodium aluminate, etc.) and calcium source materials (steel slag, carbide slag, phosphorus tailings, etc.) can undergo efficient pozzolanic reaction and secondary hydration reaction in the high-alkali environment (pH>10) provided by alkaline activation sources (red mud, magnesium slag, white mud, etc.). Sulfate reacts with active alumina in calcium and silica-alumina sources to form needle-like ettringite (AFt) crystals. These crystals exhibit significant micro-expansion characteristics, precisely compensating for chemical and drying shrinkage during the later stages of cementitious material hardening, fundamentally inhibiting cracking of the solidified body. Simultaneously, rice husk ash and lithium slag in the silica-alumina source materials are high-specific-surface-area amorphous substances rich in active silicon and aluminum components. They can fully absorb calcium hydroxide generated by the hydration reaction, further generating more calcium silicate hydrate (CSH) gel. This not only improves the density and strength of the slurry but also fills capillary pores in the hardened slurry, refines the pore size distribution, reduces shrinkage stress concentration, and further alleviates shrinkage deformation. Furthermore, fiber powder, through micro-region bridging, effectively inhibits the initiation and propagation of microcracks, constrains overall slurry shrinkage, and simultaneously enhances the toughness and crack resistance of the solidified body.

[0051] (2) Regarding anti-segregation of the slurry, the modified composite admixture serves as the "performance control core" of the system, achieving uniform and stable slurry through the synergistic effect of each component. Among them, the first functional composite agent adopts a core-shell structure design, with its core being porous silica loaded with alkanolamines and sodium thiocyanate. Alkanolamines (monoethanolamine, triethanolamine, etc.) can avoid the aggregation of hydration products, making the slurry components uniformly distributed and reducing segregation and stratification from the source; sodium thiocyanate can accelerate the early hydration reaction rate at the interface, promote early strength formation, and avoid particle settling caused by slow hydration during the construction process. The outer layer of the core-shell structure is a polyacrylic acid and aluminum alkoxide layer, which can slowly decompose upon contact with water and react with calcium ions in the hydration system to form a tough bonding layer, which not only improves the integrity of the slurry itself but also lays the foundation for subsequent bonding with aggregates. The second functional compound is composed of stearate and polyether-modified siloxane through ball milling. The polyether-modified siloxane introduces uniform and stable microbubbles during stirring, blocking the settling channels of solid particles and improving the fluidity and homogeneity of the slurry. Stearate coats the bubble surface, enhancing bubble stability, and its hydrophobicity reduces interfacial moisture accumulation, preventing slurry bleeding. Furthermore, polymer powders (ethylene-vinyl acetate, acrylate, etc.) form a film during slurry hardening, creating a three-dimensional tough network and improving the slurry's cohesiveness. Cellulose ethers (hydroxypropyl methylcellulose, etc.) have excellent water-retaining and thickening effects, increasing the slurry's yield stress and plastic viscosity, preventing moisture and fine particle loss, ultimately achieving stable slurry performance without segregation or bleeding during pouring.

[0052] (3) Regarding the bonding at the slurry-aggregate interface, this invention enhances bonding strength through a dual interface modification mechanism. On the one hand, the tough bonding layer formed by the decomposition of polyacrylic acid and aluminum alkoxide on the outer layer of the first functional composite agent can form a chemical adsorption with the surface of construction waste aggregate, filling the micropores on the aggregate surface and eliminating interfacial gaps. On the other hand, the thin film formed by the polymer powder can form a continuous transition layer at the interface between the cementitious slurry and the aggregate, tightly connecting the hydration product crystals with the aggregate and preventing the interface from becoming a weak point under stress. At the same time, the CSH gel and ettringite crystals generated by hydration can grow and overlap in the pores of the aggregate, forming a dual anchoring effect of mechanical interlocking and chemical bonding, making the cementitious slurry and construction waste aggregate form a solid whole, greatly improving the shear strength and overall stability of the pile, and preventing the interface from failing first under stress.

[0053] (4) Regarding the improvement of pile bearing capacity, this invention fills the pile hole with recycled construction waste aggregate in layers and performs dynamic compaction. With the assistance of a fast-setting binder, the construction waste aggregate is strongly compacted to form a semi-rigid skeleton structure with high density and high interlocking force. This skeleton structure can provide the core support force of the pile in advance and disperse the external load. At the same time, the interconnected pores formed inside provide channels for the subsequent penetration and filling of the curing agent slurry. Subsequently, the low-carbon, high-flow slurry prepared by this invention is injected into the aggregate skeleton. The slurry can fully fill all the interconnected pores of the skeleton under its own fluidity and capillary action, achieving "full filling of skeleton pores". After the slurry is cured, the interface between the cementitious slurry and the construction waste aggregate forms a complete whole through chemical bonding (connection of CSH gel and ettringite crystals) and mechanical interlocking (growth and anchoring of crystals in pores), constructing a composite reinforcement mechanism of "recycled aggregate skeleton bearing principal stress and high-performance cementitious material transmitting and distributing stress". This structural design not only solves the problems of easy segregation and poor interfacial bonding of traditional cast-in-place piles, but also enables the pile body to have both high strength and high toughness. Its bearing capacity far exceeds that of traditional flexible piles and ordinary cement cast-in-place piles. Indoor simulation experiments have verified that the 28-day compressive strength and splitting strength of the solidified pile of this invention are significantly higher than those of ordinary P·O 42.5 cement system, and the 90-day shrinkage deformation is more than 20% lower than that of cement benchmark group, which greatly improves the bearing capacity and long-term stability of soft soil foundation.

[0054] (5) In terms of solid waste resource utilization, the present invention uses industrial solid waste such as iron tailings, steel slag, red mud, desulfurized gypsum and recycled aggregates of construction waste as the main raw materials. The total utilization rate of solid waste exceeds 95%, realizing efficient utilization of waste resources, promoting the co-processing of "construction waste-industrial solid waste", and significantly reducing raw material costs and transportation energy consumption. Detailed Implementation

[0055] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0056] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0057] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0058] The composition of each material in the silicon-aluminum source material, calcium source material, alkaline activation source material and inert mineral admixture in the following embodiments is shown in Table 1.

[0059] Table 1. Composition of materials in silicon-aluminum source materials, calcium source materials, alkaline activation source materials, and inert mineral admixtures.

[0060] The formulations of each component in Examples 1 to 6 are shown in Table 2.

[0061] Table 2. Proportions of each component in Examples 1 to 6

[0062] Example 1 A curing agent for deep dynamic compaction in boreholes of soft soil foundations comprises the following raw materials: silicon-aluminum source material, calcium source material, sulfate material, alkaline activation source material, inert mineral admixture, fiber powder, and modified composite additive; the proportions of each raw material are shown in Table 2.

[0063] The silicon-aluminum source material is composed of iron tailings, rice husk ash, lithium slag, and waste concrete powder; The calcium source materials consist of steel slag, carbide slag, and phosphate tailings; The sulfate material is composed of desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate; The alkaline activating source material consists of red mud, magnesium slag, and white mud; The inert mineral admixture consists of gold tailings, sawdust, and waste glass powder; The fiber powder is derived from discarded fishing nets, with a length of 100 μm and a diameter of 20 μm; The modified composite admixture includes a first functional composite agent, a second functional composite agent, polymer powder, and cellulose ether; wherein, the first functional composite agent has a core-shell structure, with porous silica loaded with alkanolamine and sodium thiocyanate as the core, and polyacrylic acid and aluminum alkoxide layers coated on the outside of the core; the second functional composite agent includes stearate and polyether modified siloxane.

[0064] Preparation of modified composite admixtures: (1) Preparation of the first functional compound: Porous silica was immersed in a mixed solution containing triethanolamine and sodium thiocyanate, and the solvent was slowly evaporated at 65 °C to obtain an intermediate. A mixture of polyacrylic acid and aluminum isopropoxide was loaded onto the surface of the intermediate using a fluidized bed bottom spraying process, and dried to obtain the first functional composite agent. The mass fraction of polyacrylic acid in the polyacrylic acid and aluminum isopropoxide mixture was 10%. The process parameters for the fluidized bed bottom spraying process were: inlet air temperature of 100 °C and spraying rate of 15 mL / min. The drying method was: drying under hot air at 60 °C for 8 min; then switching to cold air for material cooling.

[0065] (2) Preparation of the second functional composite agent: calcium stearate and polyether modified siloxane were ball-milled to obtain the second functional composite agent; during the ball milling process, the ball milling speed was 80 r / min and the ball milling time was 5 min.

[0066] (3) The first functional compound, the second functional compound, ethylene-vinyl acetate redispersible latex powder and hydroxypropyl methylcellulose were ball-milled to obtain a modified composite additive; during the ball milling process, the ball milling speed was 80 r / min and the ball milling time was 10 min.

[0067] Preparation of a solidifying agent for deep dynamic compaction in boreholes in soft soil foundations: The silicon-aluminum source material, calcium source material and inert mineral admixture were subjected to a first ball milling to obtain a gelation precursor. The conditions for the first ball milling were: rotation speed of 460 r / min and ball milling time of 5 min.

[0068] The sulfate material and the alkaline activation source material were ball-milled a second time to obtain an activation mixture. The conditions for the second ball milling were: rotation speed of 400 r / min and ball milling time of 3 min.

[0069] The cementitious precursor, activating mixture, fiber powder, and modified composite admixture were subjected to a third ball milling to obtain a curing agent for deep dynamic compaction in boreholes of soft soil foundations. The conditions for the third ball milling were: rotation speed of 300 r / min and milling time of 15 min.

[0070] Example 2 A curing agent for deep dynamic compaction in boreholes of soft soil foundations comprises the following raw materials: silicon-aluminum source material, calcium source material, sulfate material, alkaline activation source material, inert mineral admixture, fiber powder, and modified composite additive; the proportions of each raw material are shown in Table 2.

[0071] The silicon-aluminum source material is composed of iron tailings, rice husk ash, lithium slag, and waste concrete powder; The calcium source materials consist of steel slag, carbide slag, and phosphate tailings; The sulfate material is composed of desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate; The alkaline activating source material consists of red mud, magnesium slag, and white mud; The inert mineral admixture consists of gold tailings, sawdust, and waste glass powder; The fiber powder is derived from discarded fishing nets, with a length of 120 μm and a diameter of 18 μm; The modified composite admixture includes a first functional composite agent, a second functional composite agent, polymer powder, and cellulose ether; wherein, the first functional composite agent has a core-shell structure, with porous silica loaded with alkanolamine and sodium thiocyanate as the core, and polyacrylic acid and aluminum alkoxide layers coated on the outside of the core; the second functional composite agent includes stearate and polyether modified siloxane.

[0072] Preparation of modified composite admixtures: (1) Preparation of the first functional compound: Porous silica was immersed in a mixed solution containing monoethanolamine and sodium thiocyanate, and the solvent was slowly evaporated at 70 °C to obtain an intermediate. A mixture of polyacrylic acid and aluminum isopropoxide was loaded onto the surface of the intermediate using a fluidized bed bottom spraying process, and dried to obtain the first functional composite agent. The mass fraction of polyacrylic acid in the polyacrylic acid and aluminum isopropoxide mixture was 15%. The process parameters for the fluidized bed bottom spraying process were: inlet air temperature of 95 °C and spraying rate of 10 mL / min. The drying method was: drying under hot air at 60 °C for 9 min; then switching to cold air for material cooling.

[0073] (2) Preparation of the second functional composite agent: Zinc stearate and polyether modified siloxane were ball-milled to obtain the second functional composite agent; during the ball milling process, the ball milling speed was 50 r / min and the ball milling time was 10 min.

[0074] (3) The first functional compound, the second functional compound, ethylene-vinyl acetate redispersible latex powder and hydroxypropyl methylcellulose were ball-milled to obtain a modified composite additive. During the ball milling process, the ball milling speed was 70 r / min and the ball milling time was 12 min.

[0075] Preparation of a solidifying agent for deep dynamic compaction in boreholes in soft soil foundations: The silicon-aluminum source material, calcium source material and inert mineral admixture were subjected to a first ball milling to obtain a gelation precursor. The conditions for the first ball milling were: rotation speed of 480 r / min and ball milling time of 6 min.

[0076] The sulfate material and the alkaline activation source material were subjected to a second ball milling to obtain an activation mixture. The conditions for the second ball milling were: a rotation speed of 380 r / min and a ball milling time of 3.5 min.

[0077] The cementitious precursor, activating mixture, fiber powder, and modified composite admixture were subjected to a third ball milling to obtain a curing agent for deep dynamic compaction in boreholes of soft soil foundations. The conditions for the third ball milling were: rotation speed of 280 r / min and milling time of 16 min.

[0078] Example 3 A curing agent for deep dynamic compaction in boreholes of soft soil foundations comprises the following raw materials: silicon-aluminum source material, calcium source material, sulfate material, alkaline activation source material, inert mineral admixture, fiber powder, and modified composite additive; the proportions of each raw material are shown in Table 2.

[0079] The silicon-aluminum source material is composed of iron tailings, rice husk ash, lithium slag, and waste concrete powder; The calcium source materials consist of steel slag, carbide slag, and phosphate tailings; The sulfate material is composed of desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate; The alkaline activating source material consists of red mud, magnesium slag, and white mud; The inert mineral admixture consists of gold tailings, sawdust, and waste glass powder; The fiber powder is derived from discarded fishing nets, with a length of 140 μm and a diameter of 16 μm; The modified composite admixture includes a first functional composite agent, a second functional composite agent, polymer powder, and cellulose ether; wherein, the first functional composite agent has a core-shell structure, with porous silica loaded with alkanolamine and sodium thiocyanate as the core, and polyacrylic acid and aluminum alkoxide layers coated on the outside of the core; the second functional composite agent includes stearate and polyether modified siloxane.

[0080] Preparation of modified composite admixtures: (1) Preparation of the first functional compound: Porous silica was immersed in a mixed solution containing triethanolamine and sodium thiocyanate, and the solvent was slowly evaporated at 75 °C to obtain an intermediate. A mixture of polyacrylic acid and aluminum sec-butoxide was loaded onto the surface of the intermediate via a fluidized bed bottom spraying process, and after drying, the first functional composite agent was obtained. The mass fraction of polyacrylic acid in the polyacrylic acid and aluminum isopropoxide mixture was 10%. The process parameters for the fluidized bed bottom spraying process were: inlet air temperature of 90 °C and spraying rate of 5 mL / min. The drying method was: drying under hot air at 60 °C for 10 min; then switching to cold air for material cooling.

[0081] (2) Preparation of the second functional composite agent: magnesium stearate and polyether modified siloxane were ball-milled to obtain the second functional composite agent; during the ball milling process, the ball milling speed was 80 r / min and the ball milling time was 10 min.

[0082] (3) The first functional compound, the second functional compound, ethylene-vinyl acetate redispersible latex powder and hydroxyethyl methyl cellulose were ball-milled to obtain a modified composite additive; during the ball milling process, the ball milling speed was 60 r / min and the ball milling time was 14 min.

[0083] Preparation of a solidifying agent for deep dynamic compaction in boreholes in soft soil foundations: The silicon-aluminum source material, calcium source material and inert mineral admixture were subjected to a first ball milling to obtain a gelation precursor. The conditions for the first ball milling were: a rotation speed of 500 r / min and a ball milling time of 7 min.

[0084] The sulfate material and the alkaline activation source material were ball-milled a second time to obtain the activation mixture. The conditions for the second ball milling were: rotation speed of 360 r / min and ball milling time of 4 min.

[0085] The cementitious precursor, activating mixture, fiber powder, and modified composite admixture were subjected to a third ball milling to obtain a curing agent for deep dynamic compaction in boreholes of soft soil foundations. The conditions for the third ball milling were: rotation speed of 260 r / min and milling time of 17 min.

[0086] Example 4 A curing agent for deep dynamic compaction in boreholes of soft soil foundations comprises the following raw materials: silicon-aluminum source material, calcium source material, sulfate material, alkaline activation source material, inert mineral admixture, fiber powder, and modified composite additive; the proportions of each raw material are shown in Table 2.

[0087] The silicon-aluminum source material is composed of iron tailings, rice husk ash, lithium slag, and waste concrete powder; The calcium source materials consist of steel slag, carbide slag, and phosphate tailings; The sulfate material is composed of desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate; The alkaline activating source material consists of red mud, magnesium slag, and white mud; The inert mineral admixture consists of gold tailings, sawdust, and waste glass powder; The fiber powder is derived from textile waste fibers, with a length of 160 μm and a diameter of 14 μm; The modified composite admixture includes a first functional composite agent, a second functional composite agent, polymer powder, and cellulose ether; wherein, the first functional composite agent has a core-shell structure, with porous silica loaded with alkanolamine and sodium thiocyanate as the core, and polyacrylic acid and aluminum alkoxide layers coated on the outside of the core; the second functional composite agent includes stearate and polyether modified siloxane.

[0088] Preparation of modified composite admixtures: (1) Preparation of the first functional compound: Porous silica was immersed in a mixed solution containing monoethanolamine and sodium thiocyanate, and the solvent was slowly evaporated at 80 °C to obtain an intermediate. A mixture of polyacrylic acid and aluminum sec-butoxide was loaded onto the surface of the intermediate using a fluidized bed bottom spraying process, and dried to obtain the first functional composite agent. The mass fraction of polyacrylic acid in the polyacrylic acid and aluminum isopropoxide mixture was 12%. The process parameters for the fluidized bed bottom spraying process were: inlet air temperature of 85 °C and spraying rate of 20 mL / min. The drying method was: drying under hot air at 60 °C for 5 min; then switching to cold air for material cooling.

[0089] (2) Preparation of the second functional composite agent: calcium stearate and polyether modified siloxane were ball-milled to obtain the second functional composite agent; during the ball milling process, the ball milling speed was 80 r / min and the ball milling time was 10 min.

[0090] (3) The first functional compound, the second functional compound, the acrylate redispersible latex powder and hydroxyethyl methyl cellulose were ball-milled to obtain the modified composite additive; during the ball milling process, the ball milling speed was 50 r / min and the ball milling time was 15 min.

[0091] Preparation of a solidifying agent for deep dynamic compaction in boreholes in soft soil foundations: The silicon-aluminum source material, calcium source material and inert mineral admixture were subjected to a first ball milling to obtain a gelation precursor. The conditions for the first ball milling were: rotation speed of 440 r / min and ball milling time of 8 min.

[0092] The sulfate material and the alkaline activation source material were ball-milled a second time to obtain an activation mixture. The conditions for the second ball milling were: a rotation speed of 340 r / min and a ball milling time of 4.5 min.

[0093] The cementitious precursor, activating mixture, fiber powder, and modified composite admixture were subjected to a third ball milling to obtain a curing agent for deep dynamic compaction in boreholes of soft soil foundations. The conditions for the third ball milling were: rotation speed of 240 r / min and milling time of 18 min.

[0094] Example 5 A curing agent for deep dynamic compaction in boreholes of soft soil foundations comprises the following raw materials: silicon-aluminum source material, calcium source material, sulfate material, alkaline activation source material, inert mineral admixture, fiber powder, and modified composite additive; the proportions of each raw material are shown in Table 2.

[0095] The silicon-aluminum source material is composed of iron tailings, rice husk ash, lithium slag, and waste concrete powder; The calcium source materials consist of steel slag, carbide slag, and phosphate tailings; The sulfate material is composed of desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate; The alkaline activating source material consists of red mud, magnesium slag, and white mud; The inert mineral admixture consists of gold tailings, sawdust, and waste glass powder; The fiber powder is derived from discarded fishing nets, with a length of 180 μm and a diameter of 12 μm; The modified composite admixture includes a first functional composite agent, a second functional composite agent, polymer powder, and cellulose ether; wherein, the first functional composite agent has a core-shell structure, with porous silica loaded with alkanolamine and sodium thiocyanate as the core, and polyacrylic acid and aluminum alkoxide layers coated on the outside of the core; the second functional composite agent includes stearate and polyether modified siloxane.

[0096] Preparation of modified composite admixtures: (1) Preparation of the first functional compound: Porous silica was immersed in a mixed solution containing triethanolamine and sodium thiocyanate, and the solvent was slowly evaporated at 60 °C to obtain an intermediate. A mixture of polyacrylic acid and aluminum alkoxychloride was loaded onto the surface of the intermediate using a fluidized bed bottom spraying process, and dried to obtain the first functional composite agent. In the polyacrylic acid and aluminum isopropoxide mixture, the mass fraction of polyacrylic acid was 14%. The process parameters for the fluidized bed bottom spraying process were: inlet air temperature of 80 °C and spraying rate of 8 mL / min. The drying method was: drying under hot air at 60 °C for 6 min; then switching to cold air for material cooling.

[0097] (2) Preparation of the second functional composite agent: Zinc stearate and polyether modified siloxane were ball-milled to obtain the second functional composite agent; during the ball milling process, the ball milling speed was 80 r / min and the ball milling time was 10 min.

[0098] (3) The first functional compound, the second functional compound, the acrylate redispersible latex powder and hydroxyethyl cellulose were ball-milled to obtain the modified composite additive; during the ball milling process, the ball milling speed was 90 r / min and the ball milling time was 9 min.

[0099] Preparation of a solidifying agent for deep dynamic compaction in boreholes in soft soil foundations: The silicon-aluminum source material, calcium source material and inert mineral admixture were subjected to a first ball milling to obtain a gelation precursor. The conditions for the first ball milling were: rotation speed of 420 r / min and ball milling time of 9 min.

[0100] The sulfate material and the alkaline activation source material were subjected to a second ball milling to obtain an activation mixture. The conditions for the second ball milling were: a rotation speed of 320 r / min and a ball milling time of 5 min.

[0101] The cementitious precursor, activating mixture, fiber powder, and modified composite admixture were subjected to a third ball milling to obtain a curing agent for deep dynamic compaction in boreholes of soft soil foundations. The conditions for the third ball milling were: rotation speed of 220 r / min and milling time of 19 min.

[0102] Example 6 A curing agent for deep dynamic compaction in boreholes of soft soil foundations comprises the following raw materials: silicon-aluminum source material, calcium source material, sulfate material, alkaline activation source material, inert mineral admixture, fiber powder, and modified composite additive; the proportions of each raw material are shown in Table 2.

[0103] The silicon-aluminum source material is composed of iron tailings, rice husk ash, lithium slag, and waste concrete powder; The calcium source materials consist of steel slag, carbide slag, and phosphate tailings; The sulfate material is composed of desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate; The alkaline activating source material consists of red mud, magnesium slag, and white mud; The inert mineral admixture consists of gold tailings, sawdust, and waste glass powder; The fiber powder is derived from recycled fibers from waste wind turbine blades, with a length of 200 μm and a diameter of 10 μm; The modified composite admixture includes a first functional composite agent, a second functional composite agent, polymer powder, and cellulose ether; wherein, the first functional composite agent has a core-shell structure, with porous silica loaded with alkanolamine and sodium thiocyanate as the core, and polyacrylic acid and aluminum alkoxide layers coated on the outside of the core; the second functional composite agent includes stearate and polyether modified siloxane.

[0104] Preparation of modified composite admixtures: (1) Preparation of the first functional compound: Porous silica was immersed in a mixed solution containing monoethanolamine and sodium thiocyanate, and the solvent was slowly evaporated at 70 °C to obtain an intermediate. A mixture of polyacrylic acid and aluminum alkoxychloride was loaded onto the surface of the intermediate using a fluidized bed bottom spraying process, and after drying, the first functional composite agent was obtained. In the polyacrylic acid and aluminum isopropoxide mixture, the mass fraction of polyacrylic acid was 13%. The process parameters for the fluidized bed bottom spraying process were: inlet air temperature of 90 °C and spraying rate of 12 mL / min. The drying method was: drying under hot air at 60 °C for 7 min; then switching to cold air for material cooling.

[0105] (2) Preparation of the second functional composite agent: magnesium stearate and polyether modified siloxane were ball-milled to obtain the second functional composite agent; during the ball milling process, the ball milling speed was 80 r / min and the ball milling time was 10 min.

[0106] (3) The first functional compound, the second functional compound, the acrylate redispersible latex powder and hydroxyethyl cellulose were ball-milled to obtain the modified composite additive; during the ball milling process, the ball milling speed was 90 r / min and the ball milling time was 9 min.

[0107] Preparation of a solidifying agent for deep dynamic compaction in boreholes in soft soil foundations: The silicon-aluminum source material, calcium source material and inert mineral admixture were subjected to a first ball milling to obtain a gelation precursor. The conditions for the first ball milling were: rotation speed of 400 r / min and ball milling time of 10 min.

[0108] The sulfate material and the alkaline activation source material were subjected to a second ball milling to obtain an activation mixture. The conditions for the second ball milling were: a rotation speed of 300 r / min and a ball milling time of 3 min.

[0109] The cementitious precursor, activating mixture, fiber powder, and modified composite admixture were subjected to a third ball milling process to obtain a curing agent for deep dynamic compaction in boreholes of soft soil foundations. The conditions for the third ball milling were: rotation speed of 200 r / min and milling time of 20 min.

[0110] Comparative Example 1 Compared with Example 1, this comparative example did not contain any modified composite additives; All other conditions are exactly the same as in Example 1.

[0111] Comparative Example 2 Compared with Example 1, this comparative example did not include the first functional compound agent in the modified composite admixture. All other conditions were exactly the same as in Example 1.

[0112] Comparative Example 3 Compared with Example 1, this comparative example did not include a second functional compound agent in the modified composite additive. All other conditions were exactly the same as in Example 1.

[0113] Comparative Example 4 Compared to Example 1, this comparative example did not include polymer powder in the modified composite additive. All other conditions were identical to those in Example 1.

[0114] Comparative Example 5 Compared to Example 1, this comparative example did not include cellulose ether in the modified composite additive. All other conditions were identical to those in Example 1.

[0115] Comparative Example 6 Compared with Example 1, the curing agent in this comparative example is ordinary Portland cement (P·O 42.5 cement).

[0116] Experimental Example 1 A construction method for deep dynamic compaction in boreholes in soft soil foundations includes the following steps: (1) At the predetermined pile location in the soft soil foundation, use mechanical drilling equipment to drill pile holes (0.5 m in diameter and 15 m in depth), and lower steel sleeves of the same diameter as the drilling depth. (2) Fill the pile hole with construction waste and lift the steel sleeve to the filling height; use a rammer to compact it to form a high-density aggregate skeleton layer; then add the solidifying agent slurry for deep compaction in the soft soil foundation hole.

[0117] Specifically, construction waste was filled in nine times. The thickness of the first layer of construction waste was 1.7 m, the thickness of the second and third layers was 2.0 m, and the thickness of the fourth to ninth layers was 1.5 m. After each filling of construction waste, the recycled aggregate was compacted with a tamping hammer 10 times within 10 minutes to form a high-density aggregate skeleton layer. The curing agent prepared in Examples 1 to 6 and Comparative Examples 1 to 6 was mixed with water at a ratio of 0.8:1 to prepare a slurry with a fluidity of 400 mm. This slurry was injected into the compacted construction waste skeleton layer through a grouting pipe until the slurry completely filled the aggregate voids and was slightly higher than the top surface of the layer.

[0118] (3) Complete the compaction and grouting of the top layer of construction waste, and cover and maintain the top of the pile.

[0119] Performance testing: The setting time and strength of the curing agents in Examples 1-6 and Comparative Examples 1-6 were tested according to GB 175-2023 "General Portland Cement". The performance indicators are shown in Table 3 below. Indoor simulation experiments were conducted on Examples 1-6 and Comparative Examples 1-6, and the resulting specimens with a height-to-diameter ratio of 1:1 were tested for compressive strength, splitting strength, shrinkage rate and bleeding rate.

[0120] The method for core sampling of pile structures is as follows: after 28 days, core samples are taken with the point at 1 / 4 of the pile diameter as the center. The core sample diameter is 150 mm, and 3 core samples are prepared per meter. The core sample height is 150 mm ± 5 mm. The compressive strength value is then tested.

[0121] Table 3. Results of Curing Agent Performance Tests

[0122] Through the synergistic hydration and structure regulation effect of the multi-solid waste cementitious system and the modified composite admixture, the curing agents in Examples 1-6 all meet the setting time and strength requirements of GB 175-2023 "General Portland Cement", and their 28-day compressive and flexural strengths are comprehensively superior to those of P in Comparative Example 6. O 42.5 cement benchmark group. In Example 2, the curing agent exhibited the best performance, indicating that the proportions of silicon-aluminum source and calcium source in the system were well-matched, and the alkalinity of the system was conducive to promoting the formation of hydration products such as ettringite. The modified composite admixture achieved efficient activation of the hydration reaction and uniform particle dispersion. Examples 1, 4, and 6 showed slightly lower performance, with their active components exhibiting slightly lower compatibility with the activation system than Example 2. In Examples 3 and 5, due to the reduced proportion of active silicon-aluminum source and the decrease in alkaline activation source, the hydration reaction rate slowed down, the initial and final setting times were prolonged, and the early and late strengths decreased slightly.

[0123] Analysis of Comparative Example 1 shows that, due to the absence of modified composite admixtures in the curing agent, the solid waste gel particles lacked dispersion and hydration activation, resulting in severe particle agglomeration. The pozzolanic reaction and secondary hydration process were significantly delayed, and the setting time far exceeded the national standard limit. The strength decreased significantly at 3d and 28d. At the same time, the toughening effect of polymer powder was missing, and the flexural strength at 28d was only 50% of that in Example 1. This indicates that the modified composite admixture is the core of hydration and performance regulation of the gel system.

[0124] Analysis of Comparative Example 2 shows that, due to the absence of the first functional composite agent in the curing agent, the particle dispersion effect of the alkanolamine in the core-shell structure was missing. The agglomeration of gel particles led to insufficient exposure of hydration active sites. At the same time, the early strength activation effect of sodium thiocyanate was missing, the early hydration process was slowed down, the initial setting time was extended by 112 min compared with Example 1, and the 3-day compressive strength decreased by 34.1%. The interfacial reinforcement effect between the outer layer of polyacrylic acid and aluminum alkoxide in the core-shell structure was missing, the overlapping growth of hydration products lacked directional control, the later strength growth was insufficient, and the 28-day compressive strength decreased by 31.2% compared with Example 1.

[0125] Analysis of Comparative Example 3 shows that, because the curing agent did not contain a second functional composite agent, the foam stabilizing and homogenizing effects of stearate and polyether-modified siloxane were missing, resulting in poor pore structure of the slurry, uneven distribution of hydration products, and a significant decrease in strength and flexural strength. However, because the hydration activation system was complete, the performance degradation was less than that of Comparative Examples 1 and 2.

[0126] Analysis of Comparative Example 4 shows that, since no polymer powder was added to the curing agent, the three-dimensional toughness network formed by polymer film was missing after the gelling system hardened, and the brittleness of the slurry increased significantly. The 28-day flexural strength decreased by 33.0% compared with Example 1; while the compressive strength was less affected, only decreasing slightly, which verifies that the core role of polymer powder is to improve the toughness and deformation coordination of the gelling system.

[0127] Analysis of Comparative Example 5 shows that because the curing agent did not contain cellulose ether, it lacked the water-retaining and thickening effect, which increased the probability of water bleeding in the slurry. The rapid loss of surface moisture led to insufficient hydration reaction, significantly shortened the initial setting time of the curing agent, prolonged the final setting time, and resulted in insufficient density of the hydration products, as well as a significant decrease in strength and flexural properties.

[0128] As can be seen from the analysis of Comparative Example 6, due to the use of P O 42.5 silicate cement has a significantly shorter setting time than the example group, but its 28-day compressive strength is only 80.6% of that of Example 1, and its flexural strength is only 79.8% of that of Example 1. The reason is that the hydration products of the pure cement system are mainly CSH gel and calcium hydroxide, lacking the gradient hydration effect of multiple solid waste active components. At the same time, it lacks the structural regulation effect of modified admixtures, and its later strength growth and toughness improvement are slightly weaker than the solid waste-based curing agent system of the present invention.

[0129] Table 4. Performance test results of indoor simulated dynamic compaction solidification piles Normal segregation: <3% is normal; 3%–5% indicates slight segregation; >5% indicates severe segregation.

[0130] Relying on the triple synergistic effect of cementitious system hydration regulation, admixture interface modification, and aggregate skeleton structure enhancement, the cured pile specimens of Examples 1-6 all showed no segregation, with bleeding rates all below 3%, 90-day shrinkage deformation all more than 20% lower than the cement reference group, and 28-day compressive and splitting tensile strengths all higher than the cement reference group. Example 2 is the optimal group, as its ratio of active component to modified admixture achieves the best match in hydration rate, slurry rheology, and interface modification effect. Therefore, the specimens exhibited optimal performance in terms of strength, crack resistance, interfacial bonding, and anti-segregation properties. Due to fluctuations in component dosage, the amount of hydration products generated in Examples 3-6 decreased, resulting in a slight decline in various properties, but they were still far superior to the comparative groups.

[0131] In terms of shrinkage control, the needle-like ettringite crystals generated by calcium and silicon-aluminum sources in an alkaline environment exhibit a micro-expansion effect, precisely compensating for the chemical and drying shrinkage during the hardening process of the cementitious material. High specific surface area rice husk ash, lithium slag, and other silicon-aluminum source materials fill the capillary pores of the hardened slurry, refine the pore size distribution, and reduce shrinkage stress. Fiber powder, through micro-region bridging, inhibits the initiation and expansion of microcracks, further constraining the overall shrinkage of the slurry. In terms of segregation control, the modified composite admixture forms a complete process control system of "dispersion-foam stabilization-water retention-thickening". The alkanolamine in the first functional composite agent achieves efficient dispersion of cementitious particles, avoiding particle agglomeration and sedimentation. The polyether-modified siloxane in the second functional composite agent introduces uniform and stable microbubbles, blocking the sedimentation channels of solid particles. The water-retaining and thickening effect of cellulose ether increases the yield stress and plastic viscosity of the slurry, avoiding bleeding and stratification, ultimately achieving the effect of no segregation and no bleeding when the slurry penetrates and fills the pores of the aggregate. In terms of interface bonding and load-bearing enhancement, the construction method of "firstly compacting to construct the aggregate skeleton, then injecting the curing agent slurry" in this invention allows the curing agent slurry to fully penetrate and fill the pores and gaps of the construction waste aggregate. After the polyacrylic acid and aluminum alkoxide on the outer layer of the core-shell structure of the first functional composite agent decompose upon contact with water, they react with calcium ions in the hydration system to form a tough bonding layer, which greatly improves the interfacial adhesion between the cementitious slurry and the hydrophobic, smooth-surfaced construction waste aggregate. The polymer powder forms a film at the interface, forming a continuous transition layer of "hydration product crystals - polymer film - aggregate interface", eliminating weak areas at the interface. The CSH gel generated by hydration and the ettringite crystals grow and overlap in the aggregate pores, forming a dual anchoring effect of mechanical interlocking and chemical bonding, ultimately achieving a specimen compressive strength and splitting tensile strength that are superior to the cement reference group.

[0132] Analysis of Comparative Example 1 shows that, due to the absence of modified composite additives in the curing agent, the system lacks the performance regulation effect of the entire process of "dispersion-foam stabilization-water retention-thickening". The cementitious slurry has poor dispersibility and lacks water retention capacity, and the shrinkage deformation is 103% higher than that of Example 1. At the same time, the interface modification effect is missing, the interfacial adhesion between the cementitious slurry and the aggregate is extremely poor, and the interface is preferentially destroyed under stress, resulting in a significant decrease in the strength and splitting toughness of the specimen.

[0133] Analysis of Comparative Example 2 shows that, due to the absence of the first functional composite agent in the curing agent, the system lacks the core particle dispersion and interface modification effects. The agglomeration of cementitious particles leads to insufficient hydration, and the slurry exhibits slight segregation. At the same time, the interfacial bonding force between the cementitious slurry and the aggregate decreases significantly. The 28-day splitting compressive strength is 43% lower than that of Example 1. The interface of the specimen is prone to cracking under stress, and the toughness and shrinkage resistance are significantly deteriorated.

[0134] Analysis of Comparative Example 3 shows that, due to the absence of a second functional composite agent in the curing agent, the system lacks the homogeneity and foam control effect of the slurry. The slurry is prone to stratification and sedimentation, manifested as slight segregation and high bleeding rate. Poor pore structure leads to increased shrinkage deformation. At the same time, the slurry does not penetrate and fill the aggregate pores evenly, resulting in a decrease in the overall density of the specimen and a significant deterioration in both strength and interfacial properties.

[0135] Analysis of Comparative Example 4 shows that, because no polymer powder was added to the curing agent, the system lacked the interfacial toughness transition and toughening effect, resulting in a significant decrease in the interfacial adhesion between the cementitious slurry and the aggregate. At the same time, the brittleness of the slurry increased, and the 28-day splitting strength decreased by 33% compared to Example 1. However, because the dispersion, water retention, and hydration activation system of the slurry were intact, there was no segregation in the specimens, and the decrease in compressive strength was relatively small.

[0136] Analysis of Comparative Example 5 shows that, due to the absence of cellulose ether in the curing agent, the system lacks water retention and thickening effects, resulting in insufficient plastic viscosity of the slurry, slight segregation, and high bleeding rate. Water loss leads to incomplete hydration reaction, decreased slurry density, and increased shrinkage deformation. At the same time, water accumulation at the aggregate interface forms a water film layer, weakening the interfacial adhesion. Ultimately, this leads to a significant deterioration in all properties of the specimen.

[0137] Analysis of Comparative Example 6 shows that, due to the use of ordinary P... The O 42.5 cement system exhibited decreased water retention and slight segregation. Calcium hydroxide generated during cement hydration accumulated at the aggregate interface, forming a weak interfacial region. The 28-day splitting strength was only 77% of that in Example 1. Simultaneously, the pure cement system lacked the micro-expansion compensation effect of ettringite, resulting in a 21% increase in shrinkage deformation at 90 days compared to Example 1. The specimens were prone to shrinkage cracking, and ultimately, the specimen strength, homogeneity, and long-term stability were all far lower than those of the curing agent system of this invention.

[0138] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A curing agent for deep dynamic compaction in boreholes of soft soil foundations, characterized in that, Its raw materials, by mass parts, include: The mixture contains 60-80 parts of silicon-aluminum source material, 40-50 parts of calcium source material, 10-30 parts of sulfate material, 5-10 parts of alkaline activation source material, 10-20 parts of inert mineral admixture, 0.1-0.5 parts of fiber powder, and 0.05-0.08 parts of modified composite additive. The silicon-aluminum source materials include iron tailings, rice husk ash, lithium slag, and waste concrete powder. The calcium source materials include steel slag, carbide slag, and phosphate tailings; The sulfate materials include desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate; The alkaline activation source materials include red mud, magnesium slag, and white mud; The inert mineral admixture includes gold tailings, sawdust, and waste glass powder; The modified composite additive includes a first functional composite agent, a second functional composite agent, polymer powder, and cellulose ether; wherein, the first functional composite agent has a core-shell structure, with porous silica loaded with alkanolamine and sodium thiocyanate as the core, and polyacrylic acid and aluminum alkoxide layers coated on the outside of the core; the second functional composite agent includes stearate and polyether-modified siloxane.

2. The curing agent as described in claim 1, characterized in that, In the silicon-aluminum source material, the mass ratio of iron tailings, rice husk ash, lithium slag and waste concrete powder is (1~2):(2~4):(0.5~1):(2~5). Alternatively, in the calcium source material, the mass ratio of steel slag, carbide slag and phosphorus tailings is (2~4):(0.5~1):(0.3~1).

3. The curing agent as described in claim 1, characterized in that, In sulfate materials, the mass ratio of desulfurized gypsum, anhydrous sodium silicate, and sodium aluminate is (10~15):(1~3):(0.5~1). Alternatively, in the alkaline activating source, the mass ratio of red mud, magnesium slag, and white mud is (5~10):(1~3):(0.5~1); Alternatively, the pH value of the alkaline excitation source is greater than 10; Alternatively, in the inert mineral admixture, the mass ratio of gold tailings, sawdust, and waste glass powder is (5~10):(3~5):(10~15). Alternatively, the fiber powder has a length of 100~200 μm and a diameter of 10~20 μm; the fiber powder is selected from at least one of textile waste fiber, waste fishing net, and recycled fiber from waste wind turbine blades.

4. The curing agent as described in claim 1, characterized in that, The preparation method of the modified composite admixture includes: ball milling a first functional composite agent, a second functional composite agent, polymer powder and cellulose ether to obtain the modified composite admixture.

5. The curing agent as described in claim 4, characterized in that, In modified composite admixtures, the preparation method of the first functional composite agent includes: Porous silica was immersed in a mixed solution containing alkanolamine and sodium thiocyanate, and the intermediate was obtained after removing the solvent. A mixture of polyacrylic acid and aluminum alkoxide was loaded onto the surface of an intermediate via a fluidized bed bottom spraying process and dried to obtain the first functional composite agent. Alkaneolamines include one or more of monoethanolamine or triethanolamine; Alternatively, aluminum alkoxides may include one or more of aluminum isopropoxide, aluminum sec-butoxide, or aluminum alkoxychloride.

6. The curing agent as described in claim 1, characterized in that, The preparation method of the second functional composite agent includes: ball milling stearate and polyether modified siloxane to obtain the second functional composite agent; Preferably, the stearate includes one or more of calcium stearate, zinc stearate, or magnesium stearate; Preferably, the mass ratio of stearate to polyether-modified siloxane is (8-10):

1. Preferably, the ball mill rotation speed is 50~80 r / min, and the ball milling time is 5~10 min; Alternatively, the polymer powder includes one or more of ethylene-vinyl acetate-based or acrylate-based redispersible latex powders; Alternatively, cellulose ethers include one or more of hydroxypropyl methylcellulose, hydroxyethyl methylcellulose, or hydroxyethyl cellulose; Alternatively, the mass ratio of the first functional compound agent, the second functional compound agent, the polymer powder, and the cellulose ether is (5~6):(0.5~1):(2~3):

1.

7. The method for preparing the solidifying agent for deep dynamic compaction in boreholes of soft soil foundations according to any one of claims 1 to 6, characterized in that, Includes the following steps: The silicon-aluminum source material, calcium source material and inert mineral admixture were ball-milled for the first time to obtain a gelation precursor; The sulfate material and the basic activation source material are ball-milled a second time to obtain an activation mixture; The gelation precursor, activating mixture, fiber powder and modified composite additives are subjected to a third ball milling to obtain a curing agent for deep dynamic compaction in holes in soft soil foundations.

8. The preparation method according to claim 7, characterized in that, The conditions for the first ball milling are: rotation speed of 400~500 r / min and ball milling time of 5~10 min; Alternatively, the conditions for the second ball milling are: rotation speed of 300~400 r / min and ball milling time of 3~5 min; Alternatively, the conditions for the third ball milling are: a rotation speed of 200~300 r / min and a ball milling time of 15~20 min.

9. A material for deep dynamic compaction in boreholes in soft soil foundations, characterized in that, Includes construction waste and the solidifying agent for deep dynamic compaction in holes of soft soil foundations as described in any one of claims 1 to 6, or the solidifying agent for deep dynamic compaction in holes of soft soil foundations prepared by the preparation method described in claim 7 or 8.

10. A construction method for deep dynamic compaction in boreholes on soft soil foundations, characterized in that, Includes the following steps: (1) At the predetermined pile location in soft soil foundation, use mechanical drilling equipment to drill pile holes and lower steel sleeves of the same diameter as the drilling depth. (2) Fill the pile hole with construction waste and lift the steel sleeve to the filling height; use a rammer to compact it to form a high-density aggregate skeleton layer; then add the solidifying agent slurry for deep dynamic compaction in the pile hole of soft soil foundation. (3) Repeat the operation in step (2) to complete the compaction and grouting of the top layer of construction waste, and cover and maintain the top of the pile.

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