Modified material for soft soil roadbed reinforcement and preparation and application methods thereof

Abstract

The invention discloses a modified material for reinforcing a soft soil roadbed as well as a preparation method and an application method of the modified material. The material comprises the following components in percentage by mass: 70-85% of engineering residue soil slurry; 8-15% of casting residue powder; 5-10% of slag powder; 2-5% of desulfurized gypsum; 1-3% of a carbon capture curing agent; and an exciting agent solution with a mass percentage of 5-8% is added. According to the method, a green low-carbon treatment path for modifying engineering muck slurry by using an industrial solid waste-based environment-friendly cementing material is utilized, casting residue powder, slag powder, desulfurized gypsum and other industrial solid wastes are selected as modified materials, and the solid waste-based cementing material solidified soil is subjected to mix proportion design through a multi-solid waste synergistic effect and an activity excitation technology; the designed mix proportion should ensure that the compressive strength can reach 0.5 MPa in 3 days and the compressive strength can reach 1.0 MPa or above in 7 days, so that the strength requirements of functional fillers and temporary construction roadbeds can be met.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials science and technology, and relates to a modified material for soft soil subgrade reinforcement, as well as its preparation and application methods. Background Art

[0002] During the construction process of civil engineering, the construction of temporary roads is a key link to ensure the smooth progress of construction. However, when encountering soft soil subgrades, the construction of temporary roads faces many challenges. Soft soil subgrades, especially the soft clay therein, often lead to long-term settlement of the subgrade due to characteristics such as high water content, low permeability, high compressibility, high sensitivity, large deformation and long duration. This not only affects the service life of the subgrade and buildings, but also poses a serious threat to construction efficiency and safety.

[0003] Traditional temporary road subgrade paving materials, such as cement concrete, asphalt and gravel, although can meet the construction requirements to a certain extent, their initial construction costs are relatively high, and they often cannot be reused after the project is completed. This not only causes a great waste of resources, but also increases the construction cost. In addition, these materials may cause damage to the original terrain during the demolition process, and the demolition cost is also relatively high, further exacerbating the economic burden of construction.

[0004] With the rapid development of modern engineering technology, traditional soft soil subgrade reinforcement methods have gradually shown their technical and economic limitations under certain complex geological environments and engineering conditions. These methods often have difficulty achieving a win-win situation of economic and environmental benefits while ensuring construction quality and safety.

[0005] To address this challenge, multidisciplinary cross-research has spawned a variety of new reinforcement materials, such as high-strength geosynthetics, eco-friendly materials and self-healing materials. These new materials demonstrate excellent efficiency in physical and chemical properties, can significantly improve the bearing capacity of soft soil subgrades, and shorten the construction period, thus effectively coping with the challenges brought by soft soil subgrades. At the same time, the deep-rooted eco-friendly concept behind these materials also ensures the minimization of environmental interference during production and application, meeting the urgent needs of current society for sustainable development.

[0006] In summary, traditional temporary road construction materials and methods have many deficiencies in soft soil subgrade reinforcement, and the emergence of new reinforcement materials provides new ideas and approaches to solve these problems. Therefore, it is necessary to conduct in-depth research and exploration on the application of new reinforcement materials in temporary road construction, with a view to achieving an overall improvement in construction efficiency, economic and environmental benefits. Summary of the Invention

[0007] The object of the present invention is to solve the problems of settlement and deformation caused by the insufficient bearing capacity of soft soil foundation in the prior art, and to provide a modified material for soft soil subgrade reinforcement and its preparation and application methods.

[0008] To achieve the above object, the present invention adopts the following technical solutions: A modified material for soft soil subgrade reinforcement, comprising the following components and mass percentage ranges: Engineering muck slurry 70 - 85%; Casting residue powder 8 - 15%; Slag powder 5 - 10%; Desulfurized gypsum 2 - 5%; Carbon capture curing agent 1 - 3%; And an activator solution with an additional mass percentage of 5 - 8%; Wherein the casting residue powder is obtained by ball - milling steel - smelting waste slag, with a specific surface area ≥ 450 m² / kg and a particle size D50 ≤ 15 μm; The slag powder is obtained by drying and ultrafine grinding of blast furnace slag, with a specific surface area ≥ 420 m² / kg; The desulfurized gypsum is a by - product of coal - fired power plant desulfurization after calcination, with a crystal water content ≤ 5%; The carbon capture curing agent is a product formed by the mineralization reaction of CO 2 with Ca(OH) 2 solution, and the purity of CaCO 3 ≥ 90%; The activator solution is a composite solution of sodium silicate with a modulus of 1.2 and sodium hydroxide, and the concentration of Na 2 O is 8 - 10%.

[0009] The engineering muck slurry is 75%; The casting residue powder is 12%; The slag powder is 8%; The desulfurized gypsum is 3%; The carbon capture curing agent is 2%; And an activator solution with an additional mass percentage of 6%.

[0010] When the desulfurized by - product of the coal - fired power plant is calcined, it is calcined at a low temperature of 200 °C for 2 hours within the range of oxygen concentration of 5% - 10% to reduce the generation of impurities.

[0011] The carbon capture curing agent is a product formed by the mineralization reaction of CO 2 with Ca(OH) 2 solution. Specifically, CO 2 is introduced into a 10% mass concentration of Ca(OH) 2 suspension at a flow rate of 0.5 - 1.5 L / min, maintaining the reaction temperature at 40 - 60 °C, and the reaction time ≥ 4 hours. After centrifugal drying, a powder with a purity of CaCO 3 ≥ 90% is obtained.

[0012] A preparation method of a modified material for soft soil subgrade reinforcement, comprising the following steps: Raw material pretreatment: Dewater the construction waste slurry until the water content does not exceed 30%; Grind the casting residue and slag separately using a ball mill to the target specific surface area; Mixing and activation: Dry mix the solid waste powders, including casting residue powder, slag powder and desulfurized gypsum, with the carbon capture curing agent in a mixer for 3 minutes; Add the activator solution to the uniformly mixed dry powder and stir for 5 minutes under the condition that the stirring speed is 120 rpm, where sodium silicate and sodium hydroxide are prepared according to a mass ratio of 3:1; Curing reaction: Mix the uniformly mixed powder with the dewatered construction waste slurry in a mixer, and control the water-binder ratio between 0.25 and 0.35; Inject the mixed mixture into a mold and carry out standard curing, that is, cure under the conditions of a temperature of 20±2°C and a humidity not lower than 95%, or use CO 2 Curing, that is, curing under CO 2 The concentration is 20% and the pressure is 0.1 MPa.

[0013] Carbonation enhancement: Use a CO 2 Curing box to carry out accelerated carbonation treatment on the cured material, and the CO 2 The feeding rate is 2 L / min and it lasts for 24 hours.

[0014] The raw material pretreatment also includes screening to ensure uniform particle size distribution and no particles larger than 15 μm.

[0015] The ball milling treatment of the casting residue powder uses a planetary ball mill with a rotation speed ≥300 rpm and a grinding time ≥2 hours; The ultra-fine grinding of the slag powder controls the residue on a 45μm sieve ≤5%.

[0016] In the mixing and activation, the solid waste powders are mixed in a double-screw mixer, and the mixing speed of the double-screw mixer is 30-50 rpm.

[0017] In the curing reaction, the uniformly mixed powder and the dewatered construction waste slurry are mixed using a planetary mixer, and the stirring speed of the planetary mixer is 50-70 rpm.

[0018] A method for applying a modified material for soft soil subgrade reinforcement specifically includes the following steps: Foundation investigation and sampling: Drill and take soil samples within the soft soil foundation range, and detect the clay content, organic matter content and water content in the soil samples; Reinforcement range calibration: Combine the geological exploration report and the on-site sounding data to determine the reinforcement boundary and mark it with lime powder; The foundation soil is turned and mixed. Use an excavator to turn the soft soil within the marked range to a depth of ≥0.8 m, evenly sprinkle the modified material and mechanically mix it; Static consolidation. The mixed soft soil is left static for ≥24 hours, and a waterproof cloth is covered during this period to prevent rain erosion; Secondary compaction. After static consolidation, mix it again, and use a roller with a weight of ≤8 t to roll it 3 - 5 times, with a compaction degree of ≥90%; Subgrade filling. Layer by layer fill the surface material and compact it to the design elevation. After compaction, the CBR value of the subgrade should be ≥6%; Quality verification. Detect the compaction degree through a dynamic cone penetration test, take samples to test the unconfined compressive strength ≥0.8 MPa, and the permeability coefficient ≤1×10^-5 cm / s.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention utilizes a green and low-carbon disposal path for modifying engineering muck slurry with an industrial solid waste-based environmental protection cementitious material. Select industrial solid wastes such as casting residue powder, slag powder, and desulfurized gypsum as the modified materials. Through the synergistic effect of multiple solid wastes and the activation technology of activity, the mix proportion of the solid waste-based cementitious material solidified soil is designed. The designed mix proportion should ensure that the compressive strength at 3 days can reach 0.5 MPa, and the compressive strength at 7 days reaches above 1.0 MPa, which can meet the strength requirements of functional fillers and temporary construction access road subgrades.

[0020] Significant low-carbon environmental protection benefits: By adopting the technical solution of the present invention, the carbon emissions throughout the life cycle can be significantly reduced. Compared with traditional technologies, the carbon emission reduction rate is as high as over 80%, which is of great significance for promoting sustainable development.

[0021] Significant cost savings: The raw material cost of the present invention is only 1 / 3 of that of traditional cement, making it more competitive in the market. At the same time, cost savings also mean that greater economic benefits can be brought to users and the whole society during production and use, which helps to promote the wide application and popularization of this technology.

[0022] Excellent performance: The permeability coefficient of the present invention reaches the standard of impervious walls (≤1×10^-8 cm / s), and has a wide range of application prospects in the fields of waterproofing and anti-seepage, including infrastructure construction fields such as construction, water conservancy, and transportation, and can provide reliable anti-seepage protection to meet the use requirements under various complex environments. Description of the Drawings

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0024] Figure 1 This is a flow chart of the application method of the modified material for soft soil subgrade reinforcement of the present invention. Specific embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0028] The present invention utilizes a green and low-carbon disposal path for modifying engineering muck slurry with industrial solid waste-based environmental protection cementitious materials. Industrial solid wastes such as casting residue powder, slag powder, and desulfurized gypsum are selected as modified materials. Through the synergistic effect of multiple solid wastes and activity excitation technology, the mix proportion design of the solid waste-based cementitious material solidified soil is carried out. The designed mix proportion should ensure that the 3-day compressive strength can reach 0.5 MPa, and the 7-day compressive strength reaches above 1.0 MPa, which can meet the strength requirements of functional fillers and the subgrade of temporary construction roads. The specific mix proportion will be adjusted according to the actual engineering requirements and material characteristics to ensure the expected engineering performance. This modified material is widely used in aspects such as temporary roads, modification and curing of pile cores in narrow sites, and construction of heavy machinery construction platforms. Through this inventive material, it has high performance, environmental protection, corrosion resistance, time and labor saving, and has achieved good technical and economic benefits.

[0029] By inventing a new type of environmentally friendly material, it aims to enhance the bearing capacity of soft soil foundations, reduce settlement and deformation caused by soil compressibility, accelerate the consolidation process of soft soil, shorten the construction period, improve the durability of roads, resist the erosion of natural factors such as water damage and freeze-thaw cycles, extend the service life of roads, and ensure that temporary roads can withstand the expected traffic loads during construction. The modified material plays a key role in the reinforcement of soft soil subgrades, not only improving the quality and efficiency of the project, but also contributing to the realization of sustainable development goals in economy, environment and society.

[0030] A modified material for soft soil subgrade reinforcement in the present invention comprises the following components and mass percentage ranges: Engineering muck slurry 70 - 85%; Casting residue powder 8 - 15%; Slag powder 5 - 10%; Desulfurized gypsum 2 - 5%; Carbon capture curing agent 1 - 3%; And an activator solution with an additional mass percentage of 5 - 8%; Wherein the casting residue powder is obtained by ball milling steel smelting waste slag, with a specific surface area ≥ 450 m² / kg and a particle size D50 ≤ 15 μm; The slag powder is obtained by drying and ultrafine grinding of blast furnace slag, with a specific surface area ≥ 420 m² / kg; The desulfurized gypsum is a by-product of coal-fired power plant desulfurization after calcination, with a crystal water content ≤ 5%. When the coal-fired power plant desulfurization by-product is calcined, it is calcined at a low temperature of 200°C for 2 hours within an oxygen concentration range of 5% - 10% to reduce the generation of impurities; The carbon capture curing agent is a product formed by the mineralization reaction of CO 2 with Ca(OH) 2 solution, and the purity of CaCO 3 ≥ 90%. The carbon capture curing agent is a product formed by the mineralization reaction of CO 2 with Ca(OH) 2 solution. Specifically, CO 2 is introduced into a 10% mass concentration Ca(OH) 2 suspension at a flow rate of 0.5 - 1.5 L / min, maintaining the reaction temperature at 40 - 60°C, with a reaction time ≥ 4 hours, and obtaining a powder with a CaCO 3 purity ≥ 90% after centrifugal drying; The activator solution is a composite solution of sodium silicate with a modulus of 1.2 and sodium hydroxide, and the Na 2 O concentration is 8 - 10%.

[0031] Preferably, the engineering muck slurry is 75%; the casting residue powder is 12%; the slag powder is 8%; the desulfurized gypsum is 3%; the carbon capture curing agent is 2%; and an activator solution with an additional mass percentage of 6%.

[0032] A preparation method of a modified material for soft soil subgrade reinforcement in the present invention comprises the following steps: Raw material pretreatment: Dewater the construction waste slurry until the water content does not exceed 30%; Grind the casting residue and slag separately using a ball mill to the target specific surface area; Screening treatment is also included to ensure uniform particle size distribution and no particles larger than 15 μm. The ball milling treatment of the casting residue powder uses a planetary ball mill with a rotation speed ≥ 300 rpm and a grinding time ≥ 2 hours; The ultra-fine grinding of the slag powder controls the residue on a 45μm sieve ≤ 5%.

[0033] Mixing and activation: Dry mix the solid waste powder, including casting residue powder, slag powder and desulfurized gypsum, with the carbon capture curing agent in a mixer for 3 minutes; In the mixing and activation, the solid waste powder is mixed in a double helix mixer, and the mixing speed of the double helix mixer is 30 - 50 rpm.

[0034] Add the activator solution to the uniformly mixed dry powder and stir for 5 minutes at a stirring speed of 120 rpm, where sodium silicate and sodium hydroxide are prepared according to a mass ratio of 3:1.

[0035] Curing reaction: Mix the uniformly mixed powder with the dewatered construction waste slurry in a mixer, and control the water-binder ratio between 0.25 and 0.35; In the curing reaction, the uniformly mixed powder and the dewatered construction waste slurry are mixed using a planetary mixer, and the stirring speed of the planetary mixer is 50 - 70 rpm.

[0036] Pour the mixed mixture into a mold and carry out standard curing, that is, cure under the conditions of a temperature of 20 ± 2°C and a humidity not lower than 95%, or use CO 2 Curing, that is, under CO 2 Cure under the conditions of a concentration of 20% and a pressure of 0.1 MPa.

[0037] Carbonation enhancement: Use a CO 2 Curing box to carry out accelerated carbonation treatment on the cured material, and the CO 2 Passing rate is 2 L / min for 24 hours.

[0038] See Table 1 for the equipment selection and parameters in the preparation process.

[0039] Table 1 Equipment selection and parameters.

[0040] The compressive strength of the present invention within 7 days ranges from 8.5 to 12.3 MPa, while the compressive strength of traditional cement curing within the same time is only 5.0 to 7.0 Mpa, with a 70% increase. The curing material of the present invention has obvious advantages in compressive strength. The permeability coefficient of the material in the present invention is 1×10^-5 cm / s, showing excellent performance in preventing the penetration of moisture or other fluids, and having higher tightness and durability. And the CO 2 emission during the production and use process is only 45 kg / m³, while the CO 2 emission during the production process of traditional cement is as high as 280 kg / m³. This reflects the significant advantages of the present invention in environmental protection, helping to reduce greenhouse gas emissions and mitigate climate change. The cost of the present invention is 120 yuan per ton, far lower than 350 yuan per ton of traditional cement. This cost advantage makes the present invention more competitive in the market, helping to reduce construction and maintenance costs.

[0041] The curing material provided by the present invention has higher compressive strength and is suitable for occasions that need to bear large loads, improving the stability and safety of engineering structures. The lower permeability coefficient means that the material of the present invention can effectively prevent the penetration of moisture and harmful substances, extending the service life of engineering structures. The significantly reduced CO 2 emission meets the current global requirements for green, low-carbon and sustainable development, helping to reduce environmental pollution and ecological damage. The lower cost gives the present invention an obvious advantage in price, helping to reduce construction and maintenance costs and improve economic benefits.

[0042] In summary, the present invention is superior to the traditional cement curing technology in terms of compressive strength, impermeability, environmental protection and economy, and has broad application prospects and market potential. See Table 2 for the performance advantages of the present invention and traditional cement curing.

[0043] Table 2 Performance Advantages (Experimental Data) The material of the present invention shows significant carbon emission reduction effects during the preparation process. Its core mechanism is that each ton of solid waste-based cementitious material can sequester about 0.15 tons of CO 2 , and the realization of this process mainly depends on CaCO 3Generation. During the preparation of the materials of the present invention, the proportion of industrial solid waste is as high as over 80%. The high utilization rate not only significantly reduces the land occupation for the storage of industrial solid waste, but also reduces the environmental pollution risk. Saving land resources, a high solid waste utilization rate means a reduction in the storage demand for a large amount of industrial solid waste, thus saving precious land resources. Reducing environmental pollution, industrial solid waste often contains harmful substances, which are likely to cause pollution to soil, water sources, etc. if not properly treated. The preparation technology of the present invention effectively reduces the potential threat to the environment by efficiently utilizing these solid wastes. Promoting circular economy, the high utilization rate of solid waste reflects the concept of resource recycling, helps to promote the resource-based, harmless and reduction treatment of industrial waste, and promotes the development of circular economy.

[0044] See Figure 1 , which is an application method of a modified material for soft soil subgrade reinforcement in the present invention, specifically including the following steps: Foundation exploration and sampling, drilling to take soil samples within the soft soil foundation range, and detecting the clay content, organic matter content and water content in the soil samples; Calibration of reinforcement range, combining the geological exploration report and the on-site sounding data, determining the reinforcement boundary and marking it with lime powder; Mixing treatment of foundation soil, using an excavator to turn over the soft soil within the marked range to a depth of ≥0.8 m, evenly spreading the modified material and mechanically mixing; Static consolidation, allowing the mixed soft soil to stand for ≥24 hours, covering with a waterproof cloth during this period to prevent rain erosion; Secondary compaction, remixing after standing, using a roller with a mass of ≤8 t to roll 3 - 5 times, with a compaction degree of ≥90%; Subgrade filling, filling the surface layer material in layers and compacting to the design elevation, with the CBR value of the subgrade after compaction ≥6%; Quality verification, detecting the compaction degree through sounding tests, sampling and testing the unconfined compressive strength ≥0.8 MPa, and the permeability coefficient ≤1×10^-5 cm / s.

[0045] Finally, make good inspection records and summaries.

[0046] The modified material in the present invention avoids the problems of time-consuming, labor-intensive and material-consuming in the traditional method in the application of soft soil subgrade reinforcement, and at the same time provides an economical, easy-to-operate and construction-safe solution.

[0047] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A modified material for reinforcing soft soil roadbed, characterized in that: Includes the following components and mass percentage ranges: Engineering slag mud 70-85%; casting slag powder 8-15%; slag powder 5-10%; desulfurized gypsum 2-5%; carbon capture curing agent 1-3%; and an additional activator solution with a mass percentage of 5-8%; The casting slag powder is obtained by ball milling waste slag from steel smelting, with a specific surface area of ​​≥450 m² / kg and a particle size D50≤15 μm; The slag powder is blast furnace slag that has been dried and ultra-finely ground, with a specific surface area of ​​≥420 m² / kg; The desulfurized gypsum is a desulfurized byproduct of a coal-fired power plant that has been calcined, and the crystal water content is ≤5%; The carbon capture solidifying agent is a product generated by the mineralization reaction of CO2 and Ca(OH)2 solution, and the purity of CaCO3 is ≥90%; The activator solution is a composite solution of sodium silicate and sodium hydroxide with a modulus of 1.2 and a Na2O concentration of 8-10%.

2. A modified material for reinforcing soft soil roadbed according to claim 1, characterized in that: The engineering slag slurry is 75%; the casting slag powder is 12%; the slag powder is 8%; the desulfurized gypsum is 3%; the carbon capture curing agent is 2%; and the activator solution with a mass percentage of 6% is added.

3. The modified material for reinforcing soft soil roadbed according to claim 1, characterized in that: The desulfurization byproducts of the coal-fired power plant are calcined at a low temperature of 200° C. for 2 hours with an oxygen concentration within a range of 5%-10% to reduce the generation of impurities.

4. The modified material for reinforcing soft soil roadbed according to claim 1, characterized in that: The carbon capture solidifying agent is a product generated by the mineralization reaction of CO2 and Ca(OH)2 solution. Specifically, CO2 is introduced into a Ca(OH)2 suspension with a mass concentration of 10% at a flow rate of 0.5-1.5 L / min, the reaction temperature is maintained at 40-60°C, the reaction time is ≥4 hours, and after centrifugal drying, a CaCO3 powder with a purity of ≥90% is obtained.

5. A method for preparing a modified material for reinforcing a soft soil roadbed, characterized in that: The following steps are involved: Raw material pretreatment: Dehydrate the slag slurry until the moisture content does not exceed 30%; Grind the casting slag and slag to the target specific surface area using a ball mill; Mixing and stimulating: dry-mix the solid waste powder, including foundry slag powder, slag powder and desulfurized gypsum, with the carbon capture curing agent in a mixer for 3 minutes; Add an activator solution to the uniformly mixed dry powder, and stir for 5 minutes at a stirring speed of 120 rpm, wherein sodium silicate and sodium hydroxide are prepared in a mass ratio of 3:1; Curing reaction: Mix the evenly mixed powder with the dehydrated slag slurry in a mixer, and control the water-binder ratio between 0.25 and 0.35; Inject the mixed material into the mold and perform standard curing, i.e. curing at a temperature of 20±2℃ and a humidity of not less than 95%, or CO2 curing, i.e. curing at a CO2 concentration of 20% and a pressure of 0.1 MPa; Carbonization enhancement: Use a CO2 curing box to accelerate the carbonization treatment of the cured material, with a CO2 injection rate of 2 L / min for 24 hours.

6. The method for preparing a modified material for reinforcing a soft soil roadbed according to claim 5, characterized in that: The raw material pretreatment also includes screening treatment to ensure uniform particle size distribution and no particles larger than 15 μm.

7. The method for preparing a modified material for reinforcing a soft soil roadbed according to claim 5, characterized in that: The ball milling treatment of the casting slag powder adopts a planetary ball mill with a rotation speed of ≥300 rpm and a grinding time of ≥2 hours; the ultrafine grinding of the slag powder controls the 45μm sieve residue to be ≤5%.

8. The method for preparing a modified material for reinforcing a soft soil roadbed according to claim 5, characterized in that: During the mixing and exciting, the solid waste powder is mixed in a double-screw mixer, and the mixing speed of the double-screw mixer is 30-50 rpm.

9. The method for preparing a modified material for reinforcing a soft soil roadbed according to claim 5, characterized in that: The powders uniformly mixed in the solidification reaction are mixed with the dehydrated slag slurry using a planetary mixer, and the stirring speed of the planetary mixer is 50-70 rpm.

10. A modified material application method for reinforcing soft soil roadbed, characterized in that: The modified material according to claims 1 to 4 is used, specifically comprising the following steps: Ground investigation and sampling: drilling holes in the soft soil foundation to take soil samples and testing the clay content, organic matter content and water content in the soil samples; Demarcate the reinforcement scope, combine the geological survey report with the on-site drilling data, determine the reinforcement boundary and mark it with lime powder; The foundation soil is turned over and mixed. Use an excavator to turn over the soft soil within the marked range to a depth of ≥0.8m, evenly spread the modified material and mix it mechanically; Allow the mixed soft soil to stand for ≥24 hours for consolidation, and cover it with waterproof cloth to prevent rain erosion; Secondary compaction: After standing, secondary mixing is performed, and rolling is performed 3-5 times with a roller ≤8t, with a compaction degree ≥90%; Roadbed filling: fill the surface material in layers and compact it to the designed elevation. After compaction, the CBR value of the roadbed shall be ≥ 6%; Quality verification: compaction is detected through drilling test, and sampling test of unconfined compressive strength is ≥0.8MPa and permeability coefficient is ≤1×10^-5cm / s.

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