Low-carbon full-solid-waste-based fluid soil and preparation method thereof

Abstract

The application discloses a kind of low-carbon full solid waste-based fluid soil and preparation method thereof, comprising: coarse crushing and fine grinding treatment is carried out to construction waste, to obtain construction waste recycled aggregate, and the particle size of construction waste recycled aggregate is 0~20mm;Construction waste recycled aggregate is mixed with mud-containing material to obtain solid waste base material;Solid waste base material is added with fluid soil curing agent and liquid component to be stirred and mixed, to obtain fluid soil mixture;Fluid soil mixture is cast into shape, to obtain fluid filling body;Fluid filling body is placed and cured, to obtain low-carbon full solid waste-based fluid soil.The embodiment can improve the fluidity of fluid soil mixture and the volume stability after hardening, reduce the risk of slow early strength development, insufficient late strength and high drying shrinkage cracking of fluid solidified soil, and make it difficult to realize the case of collaborative resource utilization of multiple solid wastes.

Description

Technical Field

[0001] The embodiments disclosed herein relate to the field of solid waste resource utilization technology, specifically to low-carbon all-solid waste-based fluidized soil and its preparation method. Background Technology

[0002] Low-carbon, all-solid-waste-based fluidized soil is a type of construction filler composed of soil, water, gelling materials, and additives. It features high fluidity, self-compacting properties, requires no vibration, and is pumpable. After solidification, it possesses a certain strength and is widely used in engineering applications such as foundation pit and trench backfilling and underground structural space filling. The preparation of low-carbon, all-solid-waste-based fluidized soil using construction waste and mud-containing materials involves crushing and screening construction waste, then mixing it with mud-containing materials, solidifying agents, and additives in a specific ratio to produce a fluidized solidified soil that can replace traditional backfill materials.

[0003] However, in practice, it has been found that when preparing low-carbon, all-solid-waste-based fluid soil using construction waste and mud-containing materials, the following technical problems are frequently encountered: Construction waste is complex in origin and highly variable in composition, containing various components such as red bricks, ceramic tile fragments, and waste concrete. The moisture content and mud content of the mud-containing materials are unstable. Existing technologies only perform simple crushing and screening of construction waste, failing to classify it according to the particle size distribution and impurity content of recycled aggregates. This results in uneven gradation of the solid waste base material, leading to low fluidity and low volume stability of the fluidized soil mixture after hardening. At the same time, traditional fluidized soil preparation usually uses general-purpose solidifying agents, failing to adapt the components to the characteristics of low activity of inert components such as red bricks and ceramic tile fragments in the solid waste base material and high fine particle content in the mud-containing materials. This makes it difficult to fully stimulate the hydration reaction of the potential active substances in the solid waste base material, resulting in slow early strength development, insufficient later strength, and a high risk of drying shrinkage and cracking in the fluidized solidified soil. In addition, existing technologies fail to fully utilize the potential cementitious activity of industrial solid wastes such as red mud, manganese slag, and mineral powder, making it difficult to achieve the synergistic resource utilization of multiple solid wastes.

[0004] The information disclosed in this background section is only intended to enhance the understanding of the background of the present disclosure concept, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The summary portion of this disclosure is intended to provide a brief overview of the concepts, which will be described in detail in the detailed description portion. This summary portion is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0006] Some embodiments of this disclosure propose low-carbon, all-solid-waste-based fluidized soil and its preparation method to solve the technical problems mentioned in the background section above.

[0007] In a first aspect, some embodiments of this disclosure provide a low-carbon, all-solid-waste-based fluidized soil and its preparation method, comprising: coarsely crushing and finely grinding construction waste to obtain recycled construction waste aggregate, wherein the particle size of the recycled construction waste aggregate is 0-20 mm; mixing the recycled construction waste aggregate with mud-containing materials to obtain a solid waste base material, wherein the mud-containing materials are obtained by pretreatment of at least one of mud, river sludge, sand-containing mud, silt, washed sand mud, mud slurry, red clay, engineering waste soil and shield tunneling mud; and mixing the above-mentioned solid waste base material with... A fluid soil solidifier and liquid components are added to the material and stirred to obtain a fluid soil mixture. The fluid soil solidifier includes the following components by weight: 20-35 parts mineral powder, 20-30 parts fly ash, and at least one of the following: 15-30 parts red mud, 0-35 parts lime, 12-35 parts cement, 3.3-5 parts sodium silicate, and 10-20 parts manganese slag. The fluid soil mixture is then cast into a mold to obtain a fluid fill body. The fluid fill body is then allowed to stand and cure to obtain low-carbon, all-solid-waste-based fluid soil.

[0008] Secondly, some embodiments of this disclosure provide a low-carbon all-solid-waste-based fluid soil, which is the low-carbon all-solid-waste-based fluid soil as described in the first aspect above.

[0009] Thirdly, some embodiments of this disclosure provide an application of low-carbon all-solid-waste-based fluidized soil in the field of solid waste resource utilization technology, wherein the low-carbon all-solid-waste-based fluidized soil is as described in the first aspect above.

[0010] The above-described embodiments of this disclosure have the following beneficial effects: Through the low-carbon, all-solid-waste-based fluidized soil and its preparation method according to some embodiments of this disclosure, the fluidity and volume stability of the fluidized soil mixture after hardening can be improved, and the problems of slow early strength development, insufficient later strength, high risk of drying shrinkage and cracking, and difficulty in achieving the synergistic resource utilization of multiple solid wastes can be reduced. The reasons for the low fluidity and volume stability of the fluidized soil mixture after hardening, the slow early strength development, insufficient later strength, high risk of drying shrinkage and cracking, and difficulty in achieving the synergistic resource utilization of multiple solid wastes in the prior art are: construction waste has complex sources and fluctuating composition, including multiple components such as red bricks, ceramic tile fragments, and waste concrete. The moisture content and mud content of the mud-containing materials are unstable. Existing technologies only perform simple crushing and screening of construction waste, failing to classify it according to the particle size distribution and impurity content of the recycled aggregate, resulting in uneven gradation of the solid waste base material and causing fluidity issues. The fluidity and volume stability of solidified soil mixtures are low. Furthermore, traditional fluidized soil preparation typically uses general-purpose curing agents, failing to adapt the components to the low activity of inert components such as red bricks and ceramic tile fragments in the solid waste substrate, as well as the high fine particle content in the mud-containing materials. This makes it difficult to fully stimulate the hydration reaction of potential active substances in the solid waste substrate, resulting in slow early strength development, insufficient later strength, and a high risk of drying shrinkage and cracking in the solidified soil. In addition, existing technologies fail to fully utilize the potential cementitious activity of industrial solid wastes such as red mud, manganese slag, and mineral powder, making it difficult to achieve the synergistic resource utilization of multiple solid wastes. Based on this, the low-carbon, all-solid-waste-based fluidized soil and its preparation method disclosed herein include: coarsely crushing and finely grinding construction waste to obtain recycled construction waste aggregate, wherein the particle size of the recycled construction waste aggregate is 0-20 mm; mixing the recycled construction waste aggregate with mud-containing materials to obtain solid waste-based material, wherein the mud-containing material is obtained by pretreatment of at least one of mud, river sludge, sand-containing mud, silt, washed sand mud, mud slurry, red clay, engineering waste soil and shield tunneling mud; and adding fluidized bed material to the solid waste-based material. A fluidized soil mixture is obtained by stirring and mixing a solidified soil agent and a liquid component. The fluidized soil agent comprises the following components in parts by weight: 20-35 parts mineral powder, 20-30 parts fly ash, and at least one of the following: 15-30 parts red mud, 0-35 parts lime, 12-35 parts cement, 3.3-5 parts sodium silicate, and 10-20 parts manganese slag. The fluidized soil mixture is then cast into a mold to obtain a fluidized fill. The fluidized fill is then allowed to cure statically to obtain low-carbon, all-solid-waste-based fluidized soil.Because of the coarse crushing and fine grinding of construction waste, the particle size of the recycled aggregate is controlled within the range of 0-20mm. This recycled aggregate is then mixed with mud-containing materials to form a solid waste base material. This allows for control over the upper limit of the particle size and gradation of the solid particles in both the recycled aggregate and the mud-containing materials, reducing unevenness caused by fluctuations in construction waste composition and excessive particle size differences. This improves the fluidity of the fluidized soil mixture and its volume stability after hardening. Furthermore, the components of the fluidized soil solidifying agent added to the solid waste base material include red mud, mineral powder, and fly ash. Since red mud is highly alkaline, it can act as an alkali activator, providing an alkaline environment to promote and continuously drive the hydration reaction of the mineral powder and fly ash. The resulting hydration products can further fill the pores inside the low-carbon, all-solid-waste-based fluidized soil, increasing its density. Furthermore, the combined effect of the alkali-activated red mud and the continuous hydration reaction of mineral powder and fly ash can stimulate the potential active substances in the solid waste substrate to participate in the hydration reaction, thereby improving the early and later strength of the low-carbon all-solid-waste-based fluidized soil and reducing the risk of cracking due to drying shrinkage. Also, by casting the fluidized soil mixture into a fluidized fill body and then allowing it to be statically cured, the hydration reaction within the fluidized fill body can continue, resulting in low-carbon all-solid-waste-based fluidized soil and achieving the synergistic resource utilization of multiple solid wastes. Attached Figure Description

[0011] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements are not necessarily drawn to scale.

[0012] Figure 1 This is a flowchart of some embodiments of the low-carbon all-solid waste-based fluidized soil and its preparation method according to the present disclosure; Figure 2 This is a comparison chart of the internal performance test results of low-carbon all-solid waste-based fluid soil according to some embodiments of the low-carbon all-solid waste-based fluid soil and its preparation method disclosed herein; Figure 3 These are internal production test images of low-carbon all-solid waste-based fluid soil according to some embodiments of the low-carbon all-solid waste-based fluid soil and its preparation method disclosed herein; Figure 4 These are physical images of the internal performance test of low-carbon all-solid waste-based fluidized soil according to some embodiments of the low-carbon all-solid waste-based fluidized soil and its preparation method disclosed herein. Detailed Implementation

[0013] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0014] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0015] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0016] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0017] The names of messages or information exchanged between multiple devices in the embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of such messages or information.

[0018] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] Figure 1 A process 100 is shown illustrating some embodiments of the low-carbon, all-solid-waste-based fluidized soil and its preparation method according to this disclosure. The method for preparing the low-carbon, all-solid-waste-based fluidized soil includes the following steps: Step 101: The construction waste is coarsely crushed and finely ground to obtain recycled aggregate from the construction waste.

[0020] In some embodiments, construction waste can be coarsely crushed and finely ground to obtain recycled construction waste aggregate. The particle size of the recycled construction waste aggregate can be 0-20 mm. The construction waste may include at least one of red bricks, wood chips, film, plastic, ceramic tile fragments, and waste concrete fragments. The film may be plastic film such as door and window protective film or packaging film peeled off during construction or decoration. The waste concrete fragments may be fragments of recycled concrete containing sand and gravel aggregate and hardened cement paste.

[0021] In some optional implementations of certain embodiments, construction waste can be coarsely crushed and finely ground to obtain recycled aggregate from construction waste through the following steps: The first step is to coarsely crush the construction waste to obtain recycled fragments. In practice, a jaw crusher can be used to crush the construction waste to obtain recycled fragments with a particle size of 30mm or less.

[0022] The second step involves finely grinding the recycled materials using a disc mill to obtain recycled aggregate from construction waste. In practice, the recycled materials can be fed into a disc mill, with a rotation speed of 200-300 rpm and a disc gap of 0.5-1.5 mm, and ground for 5-10 minutes to obtain recycled aggregate from construction waste. This coarse crushing and fine grinding process controls the particle size of the construction waste within the range of 0-20 mm, reducing unevenness in the solid waste base material caused by fluctuations in the composition or excessive differences in particle size, thereby improving the fluidity of the fluidized soil mixture and its volume stability after hardening.

[0023] Step 102: Mix the recycled aggregate from construction waste with mud-containing materials to obtain solid waste base material.

[0024] In some embodiments, the above-mentioned recycled aggregate from construction waste can be mixed with mud-containing materials to obtain solid waste base material. The mud-containing materials can be obtained by pre-treating at least one of mud, river sludge, sand-containing mud, silt, washed sand mud, slurry, red clay, engineering waste soil, and shield tunneling slurry. The above-mentioned river sludge can characterize sludge in river channels. The above-mentioned sand-containing mud can characterize natural sandy mud layers or muddy materials with a sand content between 15% and 40% generated during artificial sand washing. In practice, the above-mentioned engineering waste soil or mud can be pre-sorted and crushed sequentially, and magnetic separation can be performed using an iron remover to remove large impurities and ferromagnetic substances. Afterwards, the pre-sorted and crushed engineering waste soil or mud can be sent to a slurry preparation tank, mixed with water to form slurry, and then screened through a vibrating screen to separate the recycled aggregate. The remaining slurry after screening is conditioned with flocculant and then sent to a plate and frame filter press for dewatering to form a filter cake. Finally, the cake is crushed using a cake crusher to obtain solid waste base material. This solid waste base material may include the following components in parts by weight: 0-80 parts of the above-mentioned recycled construction waste aggregate and 20-100 parts of the above-mentioned mud-containing material. It should be noted that in Example 1, the mass of the mud-containing material can be 800g, and the mass of the recycled construction waste aggregate can be 1200g. In Example 2, the mass of the mud-containing material can be 800g, and the mass of the recycled construction waste aggregate can be 1200g. In Example 3, the mass of the mud-containing material can be 1000g, and the mass of the recycled construction waste aggregate can be 1000g.

[0025] In addressing the aforementioned technical problems in the application scenario—specifically, when low-carbon solid waste-based fluidized soil is used for backfilling underground structural sidewalls in poorly ventilated and moisture-saturated environments—the following technical problem often arises: High levels of soluble salts and alkalis in the solid waste base material and alkali metal ions in the fluidized soil solidifier continuously migrate and crystallize to the surface under the influence of capillary action from groundwater during the later stages of curing. Furthermore, the significant precipitation of salts leaves minute migration channels and pores within the low-carbon solid waste-based fluidized soil, leading to a gradual loosening of its internal structure. This results in a continuous decline in its overall bearing capacity and shear strength during service, failing to meet the requirements for long-term stable support. Considering the following requirements for this application scenario: adaptability to long-term service of low-carbon solid waste-based fluidized soil in high-humidity environments, consistency of bearing capacity across different parts of the low-carbon solid waste-based fluidized soil, and a softening coefficient of not less than 0.8, we have decided to adopt the following solution: In some optional implementations of certain embodiments, the above-mentioned recycled construction waste aggregate can be mixed with mud-containing materials in the following manner to obtain solid waste base material: The first step involves adding a chemical stabilizer to the recycled construction waste aggregate according to a preset ratio and mixing it to obtain chemically stabilized recycled construction waste aggregate. The chemical stabilizer can be a silane-based stabilizer, such as isobutyltriethoxysilane. The preset ratio can be 2% to 5% of the total mass of the recycled construction waste aggregate. In practice, 2% to 5% of the chemical stabilizer can be added to the recycled construction waste aggregate, and the mixture can be stirred for 5 to 10 minutes using a forced mixer at 40 to 80 rpm to obtain chemically stabilized recycled construction waste aggregate. This chemical stabilization treatment allows the chemical stabilizer to form a hydrophobic film on the surface and inner walls of the pores of the recycled construction waste aggregate, blocking the migration channels of water and soluble salts, thereby inhibiting the migration and precipitation of salts in the prepared low-carbon, all-solid waste-based fluidized soil during service.

[0026] The second step involves ultrasonic-assisted water immersion desalination treatment of the chemically stabilized recycled construction waste aggregate to obtain desalinated aggregate. In practice, firstly, the chemically stabilized recycled construction waste aggregate and water are added to the cleaning tank of an ultrasonic cleaner at a mass ratio of 1:3, and clean water is added to submerge the aggregate. Then, the ultrasonic cleaner is turned on, and the aggregate is immersed for 30-60 minutes under the action of ultrasonic waves at 20-40 kHz. Afterward, the liquid in the cleaning tank is drained, and the chemically stabilized recycled construction waste aggregate in the cleaning tank is rinsed again with clean water. Finally, the rinsed chemically stabilized recycled construction waste aggregate is drained to obtain desalinated aggregate. The aforementioned ultrasonic-assisted water immersion desalination treatment can accelerate the dissolution and migration of soluble salts remaining in the pores of the chemically stabilized recycled construction waste aggregate, further reducing the salt content of the chemically stabilized recycled construction waste aggregate, thereby reducing the risk of loose internal structure and decreased strength of the prepared low-carbon all-solid waste-based fluid soil during service due to salt precipitation.

[0027] The third step involves oxidizing and degrading the muddy material to obtain purified mud cake.

[0028] The fourth step involves adjusting the moisture content of the purified mud cake to obtain a controlled mud cake. In practice, the purified mud cake can be transferred to a mixing tank, the tank started and maintained at a speed of 30-60 rpm. While continuously mixing, the moisture content of the purified mud cake is monitored in real time. Water is added to the purified mud cake to achieve a moisture content of 40-55%, thus obtaining the controlled mud cake. This moisture content adjustment process maintains the controlled mud cake's moisture content at 40-55%, ensuring stable flowability of the prepared fluidized soil mixture.

[0029] The fifth step involves pre-wetting and saturating the desalinated aggregate to obtain pre-wetted aggregate. The pre-wetting and saturating treatment lasts for 12-24 hours. In practice, the desalinated aggregate is first placed in a water tank, and clean water is added until it is completely submerged. It is then soaked for 12-24 hours to allow the open pores of the desalinated aggregate to absorb water until saturated. Afterward, the desalinated aggregate is removed and drained until surface dry to obtain the pre-wetted aggregate. This pre-wetting and saturating treatment pre-fills the pores of the desalinated aggregate with water, thereby inhibiting the increase in internal porosity of the final low-carbon solid waste-based fluidized soil due to water absorption and reducing the likelihood of cracks caused by shrinkage. This improves the density and strength uniformity of the final low-carbon solid waste-based fluidized soil.

[0030] Step 6: Pre-coat the pre-wetted aggregate and natural zeolite powder in the first preset proportion to obtain zeolite-coated aggregate. The first preset proportion can be 20-30% of the total mass of the pre-wetted aggregate. In practice, 20-30% of the pre-wetted aggregate and 5-10% of the natural zeolite powder can be added together to a forced mixer and stirred at 30-60 rpm for 60-90 seconds. The water film on the surface of the pre-wetted aggregate evenly adsorbs and coats the natural zeolite powder onto the surface of the pre-wetted aggregate, resulting in zeolite-coated aggregate.

[0031] Step 7: The zeolite-coated aggregate, the control slurry cake, and the pre-wetted aggregate in the second preset ratio are subjected to gradient mixing to obtain solid waste base material. The second preset ratio can be 70-80% of the pre-wetted aggregate. In practice, firstly, the zeolite-coated aggregate and the pre-wetted aggregate in the second preset ratio are added to a twin-shaft mixer and dry-mixed at 30-40 rpm for 30-60 seconds. Then, the control slurry cake is added to the twin-shaft mixer, and mixing continues at 40-60 rpm for 90-120 seconds, ensuring the control slurry cake evenly coats the surface of the zeolite-coated aggregate and the pre-wetted aggregate, filling the voids in the zeolite-coated aggregate, thus obtaining the solid waste base material. This gradient mixing process reduces the risk of segregation and uneven slurry formation caused by adding the control slurry cake all at once.

[0032] The above-described technical solution, as an inventive point of this disclosure, solves technical problem two: the overall bearing capacity and shear strength of low-carbon solid waste-based fluidized soil continuously decline during its service life, failing to meet the requirements for long-term stable support. The reasons for this continuous decline in the overall bearing capacity and shear strength of low-carbon solid waste-based fluidized soil during its service life are as follows: the high content of soluble salts and alkalis in the solid waste base material and the alkali metal ions in the fluidized soil solidifier continuously migrate to the surface and crystallize under the capillary action of groundwater during the later stages of curing. Furthermore, the large amount of salt precipitation leaves tiny migration channels and pores within the low-carbon solid waste-based fluidized soil, causing its internal structure to gradually loosen, resulting in a continuous decline in its overall bearing capacity and shear strength during its service life, failing to meet the requirements for long-term stable support. Solving these factors can reduce the continuous decline in the overall bearing capacity and shear strength of low-carbon solid waste-based fluidized soil during its service life, thus preventing it from meeting the requirements for long-term stable support. To achieve this effect, some embodiments of this disclosure involve chemically stabilizing the recycled aggregate from construction waste, causing the soluble salts contained in the recycled aggregate to react with chemical stabilizers to form stable compounds; and using ultrasonic-assisted water leaching desalination treatment to accelerate the dissolution and migration of residual soluble salts in the recycled aggregate, thereby reducing the source of salts and alkalis in the recycled aggregate. Furthermore, by coarsely crushing and finely grinding the construction waste, the particle size of the recycled aggregate is controlled within the range of 0-20 mm, and the recycled aggregate is mixed with mud-containing materials to form a solid waste base material. This allows control over the upper limit of the particle size and the gradation of the solid particles in the recycled aggregate and mud-containing materials in the solid waste base material, reducing the unevenness of the solid waste base material caused by fluctuations in the composition of construction waste and excessive particle size differences, thereby improving the fluidity of the fluidized soil mixture and the volume stability after hardening. Furthermore, since the components of the fluidized soil solidifier added to the solid waste base material include red mud, mineral powder, and fly ash, the red mud, being highly alkaline, can act as an alkali activator, providing an alkaline environment to promote and sustain the hydration reaction of the mineral powder and fly ash. The resulting hydration products can further fill the pores inside the low-carbon solid waste-based fluidized soil, increasing its density. It can also stimulate potential active substances in the solid waste base material to participate in the hydration reaction, improving the early and later strength of the low-carbon solid waste-based fluidized soil and reducing the risk of cracking due to drying shrinkage. Additionally, by casting the fluidized soil mixture into a fluidized fill body and then allowing it to cure statically, the hydration reaction within the fluidized fill body can continue, resulting in low-carbon solid waste-based fluidized soil and achieving the synergistic resource utilization of multiple solid wastes.

[0033] In the process of adopting technical solutions to solve the technical problems mentioned above, for the application scenario: when low-carbon solid waste-based fluidized soil is used for backfilling of underground structure sidewalls in scenarios with poor ventilation and saturated humidity (such as backfilling of deep foundation pits and narrow trenches), the following technical problem often occurs: the flocculant remaining in the muddy material will be adsorbed on the surface of solid particles in the solid waste base material during the preparation of the fluidized soil mixture, resulting in an abnormal increase in the viscosity of the muddy material and a decrease in fluidity. At the same time, the bridging effect of the flocculant causes the aggregate and slurry to separate into layers during the pouring and settling period. In addition, the flocculant may desorb in an alkaline environment, making the viscosity of the muddy material unstable, further aggravating the formation of water bleeding and laitance on the top surface of the fluidized fill. During service, it continuously adsorbs moisture and corrosive media from the environment, causing the laitance layer on the top surface of the low-carbon solid waste-based fluidized soil to be prone to cracking. To address the following requirements for this application scenario: adaptability to the segregation resistance of the fluidized soil mixture and adaptability to the uniformity of the top surface of the fluidized fill, we have decided to adopt the following solution: In some optional implementations of certain embodiments, the above-mentioned muddy material can be subjected to oxidative degradation treatment to obtain purified mud cake by the following methods: The first step is to screen and remove impurities from the above-mentioned muddy material to obtain screened purified mud slurry. In practice, the muddy material can be screened through a vibrating screen equipped with a 2-5mm screen at a vibration frequency of 25-50Hz to remove large particles such as gravel and sawdust from the purified mud cake. The mud slurry flowing through the screen of the vibrating screen is then collected to obtain the screened purified mud slurry.

[0034] The second step involves rapidly mixing and homogenizing the screened and purified slurry to obtain a homogenized slurry. The mixing speed during this process is between 150 and 200 rpm, and the mixing time is between 30 and 60 seconds. In practice, the screened and purified slurry can be fed into a high-speed disperser, with the mixing speed set to 150-200 rpm and continuously mixed for 30-60 seconds to fully disperse the solid particles in the slurry until a homogenized slurry with uniform composition and no sedimentation or stratification is formed.

[0035] The third step involves adding an oxidant to the homogenized slurry and subjecting it to a first stirring treatment to obtain an oxidatively degraded slurry. The oxidant can be a hydrogen peroxide solution or a sodium hypochlorite solution, and the amount of oxidant added is 0.5% to 3% of the total mass of the homogenized slurry. The first stirring treatment lasts for 60 to 120 seconds. In practice, the homogenized slurry can first be transferred to a reactor equipped with a mechanical stirrer. The mechanical stirrer is then started and maintained at a speed of 60 to 100 rpm. While continuously stirring, an oxidant of 0.5% to 3% of the total mass of the homogenized slurry is slowly added to the homogenized slurry using a metering pump. Then, stirring can continue for 30 to 60 minutes to obtain the oxidatively degraded slurry.

[0036] The fourth step is to rinse the above-mentioned oxidative degradation slurry with clean water to obtain rinsed slurry. In practice, firstly, the above-mentioned oxidative degradation slurry can be transferred to a washing tank, and clean water is added at a mass ratio of 1:(2~4) of oxidative slurry to clean water. The paddle mixer is started and slowly stirred at a speed of 30~60 rpm for 5~10 minutes to fully disperse the above-mentioned oxidative degradation slurry and mix it with clean water. Then, it is allowed to stand and settle for 30~60 minutes. After the solid particles in the above-mentioned oxidative degradation slurry have settled naturally, the clear liquid on the upper layer of the above-mentioned oxidative degradation slurry is discharged through a siphon device to obtain rinsed slurry.

[0037] The fifth step involves adding a fourth preset proportion of xanthan gum to the above-mentioned rinsing slurry and performing slow stirring and mixing to obtain rheology-modified slurry.

[0038] The sixth step is to centrifuge and dewater the rheology-modified slurry to obtain purified slurry. In practice, the rheology-modified slurry can be pumped into a horizontal screw centrifuge using a screw pump. The centrifuge is set to a speed of 2000-3000 rpm and a differential speed of 5-15 rpm to control the moisture content of the discharged slurry cake between 40-55%. The slurry cake discharged from the outlet of the centrifuge is the deflocculating agent slurry.

[0039] The above-described technical solution, as an inventive point of this disclosure, solves technical problem three: the tendency for the laitance layer on the top surface of low-carbon, all-solid-waste-based fluidized soil to crack. The reasons for this tendency are as follows: Residual flocculants in the muddy material adsorb onto the surface of solid particles in the solid waste base material during the preparation of the fluidized soil mixture, leading to an abnormally high viscosity and decreased fluidity of the muddy material. Simultaneously, the bridging effect of the flocculant causes stratification and segregation of the aggregate and slurry during the pouring and settling period. Furthermore, the flocculant may desorb in alkaline environments, making the viscosity of the muddy material unstable, further exacerbating the formation of water seepage and laitance on the top surface of the fluidized fill. During service, this laitance continuously absorbs moisture and corrosive media from the environment, resulting in the tendency for the laitance layer on the top surface of the low-carbon, all-solid-waste-based fluidized soil to crack. Solving these factors can reduce the likelihood of cracking in the laitance layer on the top surface of the low-carbon, all-solid-waste-based fluidized soil. To achieve this effect, some embodiments of this disclosure involve screening and impurity removal of the muddy material followed by rapid stirring and homogenization. This process ensures that the solid particles in the screened and purified slurry are fully dispersed and the composition is uniform, resulting in a homogenized slurry. By adding an oxidant to the homogenized slurry for oxidative degradation, the adsorption activity and bridging effect of residual flocculants in the homogenized slurry are reduced, thereby minimizing abnormal viscosity increases and stratification of aggregates and slurry in the solid waste base. Furthermore, rinsing with clean water removes small-molecule organic matter, participating oxidants, and soluble salts generated after oxidative degradation, thus reducing the interference of residues on the slurry's stability. Furthermore, by adding xanthan gum to the rinsing slurry and slowly mixing it, the consistency of the rinsing slurry is increased, forming a uniform suspended slurry. This reduces the segregation of solid particles during the pouring and settling period. Through subsequent centrifugal dewatering, the moisture content of the rheology-modified slurry is controlled between 40% and 55%. This reduces the risk of surface bleeding and the formation of a fragile laitance layer due to excessive free water in the fluidized bed. Consequently, it reduces the likelihood of cracking of the laitance layer on the top surface of the low-carbon solid waste-based fluidized bed.

[0040] In the process of adopting technical solutions to solve the technical problems mentioned above, for the application scenario: when low-carbon solid waste-based fluidized soil is used for backfilling of underground structure sidewalls in poorly ventilated and saturated environments (such as backfilling of municipal pipeline trenches), the following technical problem often occurs: During the long-distance continuous pumping of fluidized soil mixtures, the xanthan gum molecular chains contained in the fluidized soil mixture undergo irreversible degradation under the action of shear refinement, resulting in a continuous decrease in the viscosity of the fluidized soil mixture slurry and a gradual loss of its aggregate suspension capacity. This leads to the deposition of the aggregate in the pumping pipeline, which can easily cause pipe blockage. In addition, the fluidized fill undergoes segregation again during the static period after pouring, resulting in a decrease in the overall bearing capacity of the low-carbon solid waste-based fluidized soil. To address the following requirements for this application scenario: maintaining stable yield stress in the fluidized soil mixture during pumping, maintaining anti-segregation properties after pumping, and preventing segregation during the static pouring period, we have decided to adopt the following solution: In some optional implementations of certain embodiments, a fourth predetermined proportion of xanthan gum can be added to the above-mentioned rinsing slurry, and a slow stirring and mixing process can be performed to obtain a rheology-modified slurry: The first step involves dry-mixing the xanthan gum in the fourth preset ratio and the nano-silica powder in the fifth preset ratio to obtain a pre-dispersed xanthan gum-nano-silica composite powder. The fourth preset ratio can be 0.1-0.5% of the total mass of the rinsing slurry. The fifth preset ratio can be 0.5-2% of the fourth preset ratio. In practice, the xanthan gum in the fourth preset ratio and the nano-silica powder in the fifth preset ratio can be added together to a high-speed mixer and dry-mixed at 800-1200 rpm for 3-5 minutes to obtain the pre-dispersed xanthan gum-nano-silica composite powder. The ultra-high specific surface area and the abundance of silanol groups on the surface of the pre-dispersed xanthan gum-nano-silica composite powder allow it to adsorb onto the surface of the xanthan gum during dry mixing, forming a physical barrier and reducing the aggregation of xanthan gum during the hydration reaction.

[0041] The second step involves slowly adding the pre-dispersed xanthan gum nano-silica composite powder to pre-cooled water and stirring to disperse it, thereby obtaining a xanthan gum pre-hydrated solution. The pre-cooled water can be water at a temperature of 10-15°C. In practice, the pre-dispersed xanthan gum nano-silica composite powder can be added to a third preset proportion of pre-cooled water and stirred at 100-150 rpm for 15-20 minutes at 10-15°C to obtain the xanthan gum pre-hydrated solution. The third preset proportion can be 500-1000% of the total mass of the pre-dispersed xanthan gum nano-silica composite powder. The low temperature of the pre-cooled water slows down the swelling and hydration reaction rate of the xanthan gum, resulting in a uniformly extended state of the xanthan gum molecular chains in the pre-hydrated solution. This reduces local aggregation of the xanthan gum molecular chains caused by excessively rapid hydration, improving the dispersion uniformity and thickening efficiency of the pre-hydrated solution in subsequent steps.

[0042] The third step involves adding a sixth predetermined proportion of sodium trimetaphosphate to the xanthan gum prehydration solution and performing a second stirring treatment to obtain a slightly cross-linked xanthan gum solution. The sixth predetermined proportion can be 2.5% of the fourth predetermined proportion. In practice, firstly, the sixth predetermined proportion of sodium trimetaphosphate can be dissolved in pre-cooling water to prepare a sodium trimetaphosphate aqueous solution. The mass of the pre-cooling water can be 3 to 8 times the mass of the sodium trimetaphosphate. Then, while continuously stirring the sodium trimetaphosphate aqueous solution, it is slowly added to the xanthan gum prehydration solution, and the pH of the mixed solution is adjusted to 11 using a 3 mol / L NaOH solution. The solution is then stirred for 1 hour at a constant temperature of 25°C. Finally, the pH of the mixed solution is adjusted to neutral using a 1 mol / L HCl solution to obtain a slightly cross-linked xanthan gum solution. This mixed solution can be the xanthan gum prehydration solution after adding the sodium trimetaphosphate aqueous solution.

[0043] Fourth, add sodium carboxymethyl cellulose at a seventh predetermined ratio to the above-mentioned mildly cross-linked xanthan gum solution, and perform a third stirring treatment to obtain a composite rheology modifier solution. The seventh predetermined ratio can be 25% to 100% of the xanthan gum mass in the above-mentioned mildly cross-linked xanthan gum solution. In practice, the sodium carboxymethyl cellulose at the seventh predetermined ratio can be slowly added to the above-mentioned mildly cross-linked xanthan gum solution, and stirred at 100-150 rpm for 15-20 minutes to dissolve the sodium carboxymethyl cellulose and mix it with the above-mentioned mildly cross-linked xanthan gum solution to obtain the composite rheology modifier solution.

[0044] Fifth, according to the preset stirring speed, the above-mentioned composite rheology modifier solution is added to the above-mentioned rinsing slurry and stirred to obtain the initial rheology-modified slurry. The preset stirring speed can be 50-60 rpm. In practice, the above-mentioned rinsing slurry can be placed in a slurry mixer, and under the preset stirring speed of 50-60 rpm, the above-mentioned composite rheology modifier solution is thoroughly mixed with the above-mentioned rinsing slurry and adsorbed onto the surface of the solid particles of the above-mentioned rinsing slurry to obtain the initial rheology-modified slurry.

[0045] Step 6: Add borax at an eighth predetermined ratio to the initial rheology-modified mud and perform slow stirring to obtain rheology-modified mud. The eighth predetermined ratio can be 0.5-1.5% of the fourth predetermined ratio. In practice, the borax at the eighth predetermined ratio can be dissolved in pre-cooling water to prepare a borax aqueous solution. The mass of the pre-cooling water can be 3-8 times the mass of the borax. Then, under low-speed stirring conditions of 30-50 rpm, slowly add the borax aqueous solution to the initial modified mud and continue stirring for 30-60 seconds to allow the borax to contact and cross-link with the hydroxyl groups on the xanthan gum and sodium carboxymethyl cellulose molecular chains in the initial rheology-modified mud, thus obtaining the rheology-modified mud.

[0046] The above-described technical solution, as an inventive point of this disclosure, solves technical problem four: the ease with which pipes become clogged and the overall bearing capacity of low-carbon solid waste-based fluidized soil decreases. The reasons for this are as follows: During long-distance continuous pumping of the fluidized soil mixture, the xanthan gum molecules in the slurry undergo irreversible degradation under shear refinement, leading to a continuous decrease in the viscosity of the slurry and a gradual loss of aggregate suspension capacity. This causes the aggregate to deposit in the pumping pipeline, easily resulting in pipe clog. Furthermore, the fluidized fill undergoes further segregation during the settling period after pouring, contributing to the decrease in the overall bearing capacity of the low-carbon solid waste-based fluidized soil. Solving these factors can reduce the likelihood of pipe clog and the decrease in the overall bearing capacity of the low-carbon solid waste-based fluidized soil. To achieve this effect, some embodiments of this disclosure involve dry mixing xanthan gum and nano-silica powder, allowing the nano-silica to adsorb onto the surface of the xanthan gum particles, forming physical isolation and reducing the aggregation of xanthan gum during the hydration reaction. Furthermore, by slowly adding the dry-mixed pre-dispersed xanthan gum nano-silica composite powder to pre-cooled water, the low temperature condition delays the aggregation of xanthan gum during the hydration reaction. Simultaneously, the slow addition of the dry-mixed dispersed xanthan gum nano-silica composite powder to the pre-cooled water further slows the hydration expansion rate of xanthan gum, thereby ensuring that the xanthan gum molecular chains are uniformly extended in the xanthan gum pre-hydrated solution. Additionally, by adding sodium trimetaphosphate to the xanthan gum pre-hydrated aqueous solution for a second stirring treatment, sodium trimetaphosphate undergoes a cross-linking reaction with the hydroxyl groups on the xanthan gum molecular chains, forming covalent bonds between the xanthan gum molecular chains, thereby enhancing the xanthan gum molecular chains' resistance to irreversible degradation. Furthermore, by adding sodium carboxymethyl cellulose to the xanthan gum solution, the sodium carboxymethyl cellulose molecular chains and xanthan gum molecular chains form an interpenetrating polymer network through hydrogen bonds. Under shear refinement, the sodium carboxymethyl cellulose molecular chains can preferentially withstand mechanical degradation, thus protecting the covalent structure of xanthan gum from damage. Also, by adding borax to the initial rheology-modified slurry, borax dissociates in water to release borate ions, which then undergo a complexation reaction with the hydroxyl groups on the molecular chains of xanthan gum and sodium carboxymethyl cellulose to form borate ester bonds. This allows the low-carbon, all-solid-waste-based fluidized soil to maintain its anti-segregation properties during the post-casting settling period, thereby reducing the likelihood of pipe blockage and a decrease in the overall bearing capacity of the low-carbon, all-solid-waste-based fluidized soil.

[0047] Step 103: Add fluid soil solidifying agent and liquid components to solid waste base material and stir to mix to obtain fluid soil mixture.

[0048] In some embodiments, a fluidized soil solidifier and liquid components can be added to the aforementioned solid waste base material and stirred to obtain a fluidized soil mixture. The mass ratio of the fluidized soil solidifier to the aforementioned solid waste base material is 1:(4~10), and the target flowability of the fluidized soil mixture can be 180~220 mm. The fluidized soil solidifier may include the following components in parts by weight: 20~35 parts mineral powder and 20~30 parts fly ash. The fluidized soil solidifier may also include at least one of the following: 15~30 parts red mud, 0~35 parts lime, 12~35 parts cement, 3.3~5 parts sodium silicate, and 10~20 parts manganese slag. The lime may be either hydrated lime or quicklime. The lime can promote the hydration reaction of the aforementioned mineral powder and fly ash by providing calcium ions and an alkaline environment, thereby improving the strength of the fluidized fill. The sodium silicate mentioned above can promote the dispersion and cementation of clay particles in the solid waste substrate by providing soluble silicate ions, thereby improving the early strength and impermeability of the fluidized bed. The liquid component may include a water-reducing agent and water. The mass ratio of the water-reducing agent to the solid waste substrate can be 1:(33.3~1000). The mass ratio of water to the solid waste substrate can be 1:(3.3~5). The fluidized bed solidifier may also include the following component in parts by weight: 3~8 parts of a bio-enzyme soil stabilizer. The bio-enzyme soil stabilizer can catalyze the chemical reaction on the surface of clay particles in the solid waste substrate, reduce the water repellency of the clay particles, and promote the compaction and cementation between the clay particles, thereby improving the workability of the fluidized bed mixture and increasing the strength and impermeability of the fluidized bed.

[0049] In some optional implementations of certain embodiments, the fluidized soil solidification agent and liquid components can be added to the above-mentioned solid waste base material and mixed by stirring to obtain a fluidized soil mixture: The first step is to weigh the above-mentioned fluidized soil solidifier and liquid components separately. In practice, the fluidized soil solidifier can be weighed using a screw weigher, and the water-reducing agent can be weighed using a liquid metering pump. It should be noted that when it is necessary to improve the early strength of the low-carbon, all-solid-waste-based fluidized soil, or when the source of manganese slag or red mud is insufficient, 12-35 parts of cement can be added to the above-mentioned fluidized soil solidifier. When the moisture content of the above-mentioned mud-containing material is low (less than 40%), i.e., the above-mentioned solid waste base material is relatively dry, the amount of water can be increased to make the mass ratio of water to solid waste base material 1:3.3. When the moisture content of the above-mentioned mud-containing material is high (greater than 50%), i.e., the above-mentioned solid waste base material is relatively wet, the amount of water can be reduced to make the mass ratio of water to solid waste base material 1:5. When it is necessary to improve the fluidity of the above-mentioned fluidized soil mixture without increasing the amount of water, the amount of water-reducing agent can be increased to make the mass ratio of water-reducing agent to solid waste base material 1:33.3. When the fluidity of the above-mentioned fluidized soil mixture meets the requirements, the amount of water-reducing agent can be reduced to make the mass ratio of water-reducing agent to solid waste base material 1:1000. In Example 1, the mass of the fluidized soil solidifying agent can be 240g, the mass of the water-reducing agent can be 3g, and the mass of water can be 300g. In Example 2, the mass of the fluidized soil solidifying agent can be 300g, the mass of the water-reducing agent can be 2.3g, and the mass of water can be 350g. In Example 3, the mass of the fluidized soil solidifying agent can be 300g, the mass of the water-reducing agent can be 3g, and the mass of water can be 317g. When it is necessary to further improve the utilization rate of solid waste and the early strength requirements of low-carbon solid waste-based fluid soil are moderate (7-day unconfined compressive strength greater than or equal to 0.4 MPa), 20 to 35 parts of manganese slag can be added to the above-mentioned fluid soil solidifying agent.

[0050] The second step involves adding the aforementioned fluidized soil solidifier to the aforementioned solid waste base material for a first stirring treatment, resulting in a solidifier-base material mixture. The fourth stirring treatment can last for 60-120 seconds. In practice, a twin-shaft mixer can be used to stir the fluidized soil solidifier and the aforementioned solid waste base material for 60-120 seconds to ensure uniform mixing.

[0051] The third step involves adding the liquid component to the curing agent base mixture for a fifth stirring treatment to obtain a fluidized soil mixture. The duration of this fifth stirring treatment can be 60-120 seconds. In practice, the liquid component can be sprayed into the twin-shaft mixer through an atomizing nozzle, and stirring can continue until the mixture of the liquid component and the curing agent base mixture reaches the target fluidity. The target fluidity can be 180-220 mm. Then, the fluidized soil curing agent and the liquid component can be further stirred to obtain the fluidized soil mixture. The combined action of red mud, mineral powder, and fly ash can stimulate the hydration reaction of active substances in the solid waste base material, improving the early and later strength of the fluidized solidified soil and reducing the risk of cracking due to drying shrinkage. Simultaneously, by adjusting the fluidity of the fluidized mixture using the liquid component, the dosage can be controlled without sacrificing the workability of the fluidized mixture, reducing the decrease in strength and increase in drying shrinkage caused by excessive water usage.

[0052] Step 104: The fluidized soil mixture is poured into shape to obtain a fluidized fill body.

[0053] In some embodiments, the fluidized soil mixture can be cast into a shape to obtain a fluidized fill body. In practice, firstly, the fluidized soil mixture can be pumped to the casting section. The casting section can be a trench. Then, the casting section can be cast in layers to obtain the fluidized fill body. The thickness of the first layer in the layered casting process does not exceed 0.5m. The thickness of each subsequent layer can not exceed 1m.

[0054] Step 105: Allow the above-mentioned fluidized fill to stand for curing to obtain low-carbon, all-solid-waste-based fluidized soil.

[0055] In some embodiments, the above-mentioned fluidized fill can be statically cured to obtain low-carbon, all-solid-waste-based fluidized soil.

[0056] In some optional implementations of certain embodiments, the above-mentioned fluidized fill can be statically cured through the following steps to obtain low-carbon, all-solid-waste-based fluidized soil: The first step is to clean and level the exposed surfaces of the final-set fluidized bed fill to obtain the fill to be covered. In practice, the top and side surfaces of the final-set fluidized bed fill can be cleaned with a brush or compressed air to remove surface dust, and then compacted with a trowel to eliminate honeycomb, pitting, and unevenness, making the exposed surfaces flat and dense, thus obtaining the fill to be covered.

[0057] The second step involves covering the fill material to be covered with a membrane according to a preset interval, resulting in a membrane-covered fill material. In practice, firstly, after the surface cleaning and leveling are completed, the fill material to be covered can be left to stand for 30-60 minutes. Then, a polyethylene plastic film with a thickness of 0.08-0.12 mm can be used to cover the exposed surface of the fill material, with an overlap width of not less than 100 mm. The edges of the polyethylene plastic film are then secured with tape to ensure a tight fit between the polyethylene film and the surface of the fill material, thus obtaining the membrane-covered fill material.

[0058] The third step is to perform moisture-retaining curing treatment on the above-mentioned membrane-covered infill, resulting in a cured infill. The curing time for this moisture-retaining treatment shall not be less than the preset curing time, which can be 7 days. In practice, after the membrane treatment is completed, a corner of the polyethylene plastic film can be peeled off every 2-4 hours to check the surface moisture of the membrane-covered infill. If the surface of the membrane-covered infill appears dry and white, water can be sprayed onto the surface, and the polyethylene plastic film should be immediately re-covered after spraying. Then, the membrane-covered infill can be kept continuously moist under the polyethylene plastic film for a cumulative curing time of not less than 7 days to obtain the cured infill.

[0059] The fourth step is to perform surface water replenishment treatment on the cured fill material to obtain a water-replenished cured fill material. In practice, after the above moisturizing curing treatment, the polyethylene plastic film covering the surface of the cured fill material can be removed, and clean water can be evenly sprayed onto the exposed surfaces such as the top and sides of the cured fill material using a sprayer to obtain a water-replenished cured fill material.

[0060] The fifth step is to perform thermal insulation treatment on the above-mentioned water-replenished curing fill to obtain a thermally insulated curing fill. In practice, immediately after the surface water-replenishing treatment, a layer of thermal insulation cotton blanket with a thickness of 20-30mm can be covered on the exposed surface of the water-replenished curing fill. The overlap width of the thermal insulation cotton blanket should not be less than 150mm, and it should be compacted and fixed with heavy objects to ensure that the thermal insulation cotton blanket is in close contact with the water-replenished curing fill. The thermal insulation cotton blanket should be kept dry, and the insulation time should not be less than 24 hours to obtain a thermally insulated curing fill.

[0061] Step 6: According to the preset curing time, remove the covering film from the above-mentioned thermal insulation curing fill to obtain low-carbon, all-solid-waste-based fluid soil. In practice, after the insulation treatment is completed, first uncover and remove the insulation blanket covering the surface of the above-mentioned thermal insulation curing fill, and then remove the polyethylene plastic film tightly attached to the surface of the above-mentioned thermal insulation curing fill. After removal, check the surface of the above-mentioned thermal insulation curing fill for any local defects such as cracks, peeling, or damage, and repair the aforementioned local defects. Then, allow the surface of the above-mentioned thermal insulation curing fill to air dry naturally to obtain low-carbon, all-solid-waste-based fluid soil. The 7-day unconfined compressive strength of the above-mentioned low-carbon, all-solid-waste-based fluid soil measured under standard curing conditions is 0.8~2.0 MPa, and the 28-day unconfined compressive strength is 1.0~6.0 MPa. It should be noted that the 7-day and 28-day unconfined compressive strengths in Example 1 are 1.402 MPa and 1.8 MPa, respectively. The 7-day and 28-day unconfined compressive strengths in Example 2 are 1.671 MPa and 2.0 MPa, respectively. The 7-day and 28-day unconfined compressive strengths in Example 3 are 2.307 MPa and 2.5 MPa, respectively.

[0062] like Figure 2 As shown, Figure 2 This can characterize the 10-day unconfined compressive strength of the low-carbon, all-solid-waste-based fluid soils prepared in Examples 1-3. Figure 2 It can be seen that the 10-day unconfined compressive strength of the low-carbon solid waste-based fluid soil prepared in Examples 1-3 is greater than 1.4 MPa, which indicates that the low-carbon solid waste-based fluid soil prepared in this application has good bearing capacity.

[0063] Figure 3 and Figure 4 This can characterize the solidification process of the low-carbon, all-solid waste-based fluid soil prepared in this application under standard curing conditions and its uniaxial compressive failure mode under ultimate bearing capacity. Figure 3 It can be seen that the low-carbon, all-solid waste-based fluid soil prepared in this application possesses good water retention and stable solidification characteristics. Figure 4 It can be seen that the low-carbon solid waste-based fluid soil prepared in this application exhibits typical failure characteristics of brittle materials under uniaxial compression. Its mechanical behavior is consistent with the material properties of fluidized solid soil. Therefore, the feasibility of the low-carbon solid waste-based fluid soil and its preparation method in this application can be confirmed.

[0064] The above-described embodiments of this disclosure have the following beneficial effects: Through the low-carbon, all-solid-waste-based fluidized soil and its preparation method according to some embodiments of this disclosure, the fluidity and volume stability of the fluidized soil mixture after hardening can be improved, and the problems of slow early strength development, insufficient later strength, high risk of drying shrinkage and cracking, and difficulty in achieving the synergistic resource utilization of multiple solid wastes can be reduced. The reasons for the low fluidity and volume stability of the fluidized soil mixture after hardening, the slow early strength development, insufficient later strength, high risk of drying shrinkage and cracking, and difficulty in achieving the synergistic resource utilization of multiple solid wastes in the prior art are: construction waste has complex sources and fluctuating composition, including multiple components such as red bricks, ceramic tile fragments, and waste concrete. The moisture content and mud content of the mud-containing materials are unstable. Existing technologies only perform simple crushing and screening of construction waste, failing to classify it according to the particle size distribution and impurity content of the recycled aggregate, resulting in uneven gradation of the solid waste base material and causing fluidity issues. The fluidity and volume stability of solidified soil mixtures are low. Furthermore, traditional fluidized soil preparation typically uses general-purpose curing agents, failing to adapt the components to the low activity of inert components such as red bricks and ceramic tile fragments in the solid waste substrate, as well as the high fine particle content in the mud-containing materials. This makes it difficult to fully stimulate the hydration reaction of potential active substances in the solid waste substrate, resulting in slow early strength development, insufficient later strength, and a high risk of drying shrinkage and cracking in the solidified soil. In addition, existing technologies fail to fully utilize the potential cementitious activity of industrial solid wastes such as red mud, manganese slag, and mineral powder, making it difficult to achieve the synergistic resource utilization of multiple solid wastes. Based on this, the low-carbon, all-solid-waste-based fluidized soil and its preparation method disclosed herein include: coarsely crushing and finely grinding construction waste to obtain recycled construction waste aggregate, wherein the particle size of the recycled construction waste aggregate is 0-20 mm; mixing the recycled construction waste aggregate with mud-containing materials to obtain solid waste base material, wherein the mud-containing materials are obtained by pretreatment of at least one of mud, river sludge, sand-containing mud, silt, washed sand mud, mud slurry, red clay, engineering waste soil and shield tunneling mud; adding fluidized bed material to the solid waste base material. A fluidized soil mixture is obtained by stirring and mixing a solidified soil agent and a liquid component. The fluidized soil agent comprises the following components in parts by weight: 20-35 parts mineral powder, 20-30 parts fly ash, and at least one of the following: 15-30 parts red mud, 0-35 parts lime, 12-35 parts cement, 3.3-5 parts sodium silicate, and 10-20 parts manganese slag. The fluidized soil mixture is then cast into a mold to obtain a fluidized fill. The fluidized fill is then allowed to cure statically to obtain low-carbon, all-solid-waste-based fluidized soil.Because of the coarse crushing and fine grinding of construction waste, the particle size of the recycled aggregate is controlled within the range of 0-20mm. This recycled aggregate is then mixed with mud-containing materials to form a solid waste base material. This allows for control over the upper limit of the particle size and gradation of the solid particles in both the recycled aggregate and the mud-containing materials, reducing unevenness caused by fluctuations in construction waste composition and excessive particle size differences. This improves the fluidity of the fluidized soil mixture and its volume stability after hardening. Furthermore, the components of the fluidized soil solidifying agent added to the solid waste base material include red mud, mineral powder, and fly ash. Since red mud is highly alkaline, it can act as an alkali activator, providing an alkaline environment to promote and continuously drive the hydration reaction of the mineral powder and fly ash. The resulting hydration products can further fill the pores inside the low-carbon, all-solid-waste-based fluidized soil, increasing its density. Furthermore, the combined effect of the alkali-activated red mud and the continuous hydration reaction of mineral powder and fly ash can stimulate the potential active substances in the solid waste substrate to participate in the hydration reaction, thereby improving the early and later strength of the low-carbon all-solid-waste-based fluidized soil and reducing the risk of cracking due to drying shrinkage. Also, by casting the fluidized soil mixture into a fluidized fill body and then allowing it to be statically cured, the hydration reaction within the fluidized fill body can continue, resulting in low-carbon all-solid-waste-based fluidized soil and achieving the synergistic resource utilization of multiple solid wastes.

Claims

1. A low-carbon, all-solid-waste-based fluidized soil and its preparation method, comprising: Construction waste is subjected to coarse crushing and fine grinding to obtain recycled construction waste aggregate, wherein the particle size of the recycled construction waste aggregate is 0~20mm; The recycled aggregate from construction waste is mixed with mud-containing materials to obtain solid waste base material. The mud-containing materials are obtained by pretreatment of at least one of mud, river sludge, sand-containing mud, silt, washed sand mud, mud slurry, red clay, engineering waste soil and shield tunneling mud. A fluid soil solidifying agent and liquid components are added to the solid waste base material and stirred to obtain a fluid soil mixture. The fluid soil solidifying agent comprises the following components in parts by weight: 20-35 parts mineral powder, 20-30 parts fly ash, and the fluid soil solidifying agent also includes at least one of the following: 15-30 parts red mud, 0-35 parts lime, 12-35 parts cement, 3.3-5 parts sodium silicate, and 10-20 parts manganese slag. The fluidized soil mixture is poured into a mold to obtain a fluidized fill body; The fluidized fill was left to cure statically to obtain low-carbon, all-solid-waste-based fluidized soil.

2. The method according to claim 1, wherein, The construction waste includes at least one of red bricks, ceramic tile fragments, and small pieces of waste concrete.

3. The method according to claim 1, wherein, The fluid soil stabilizer also includes the following components in parts by weight: 3-8 parts of bio-enzyme soil stabilizer.

4. The method according to claim 1, wherein, The solid waste base material comprises the following components in parts by weight: 0-80 parts of the recycled aggregate from construction waste and 20-100 parts of the mud-containing material.

5. The method according to claim 1, wherein, The mass ratio of the fluidized soil solidifying agent to the solid waste base material is 1:(4~10), and the target fluidity of the fluidized soil mixture is 180~220mm.

6. The method according to claim 1, wherein, The liquid component includes a water-reducing agent and water, wherein the mass ratio of the water-reducing agent to the solid waste base material is 1:(33.3~1000), and the mass ratio of the water to the solid waste base material is 1:(3.3~5).

7. The method according to claim 1, wherein, The target 7-day compressive strength of the low-carbon solid waste-based fluid soil is 0.8 MPa to 2.0 MPa, and the target 28-day compressive strength is 1.0 MPa to 6.0 MPa.

8. The method according to claim 1, wherein, The static curing of the fluidized fill body to obtain low-carbon, all-solid-waste-based fluidized soil includes: The exposed surface of the final solidified fluidized fill is cleaned and leveled to obtain the fill to be covered. According to a preset interval, the fill material to be covered is covered with a membrane to obtain a membrane-covered fill material. The membrane-covered infill is subjected to a moisture-retaining curing treatment to obtain a cured infill, wherein the curing time of the moisture-retaining curing treatment is not less than the preset curing time. The cured fill body is then subjected to surface water replenishment treatment to obtain a water-replenished cured fill body; The water-replenished curing fill is then subjected to thermal insulation treatment to obtain a thermally insulated curing fill. According to the preset curing time, the thermal insulation and curing fill is subjected to membrane removal treatment to obtain low-carbon solid waste-based fluid soil.

9. A low-carbon, all-solid-waste-based fluid soil, wherein, The low-carbon all-solid waste-based fluid soil is the low-carbon all-solid waste-based fluid soil as described in any one of claims 1-8.

10. The application of a low-carbon, all-solid-waste-based fluidized soil in the field of solid waste resource utilization technology, wherein, The low-carbon all-solid waste-based fluid soil is the low-carbon all-solid waste-based fluid soil as described in any one of claims 1-8.

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