Method for preparing flow-state solidified soil based on waste shield slurry

Abstract

The invention discloses a method for preparing flow-state solidified soil based on waste shield slurry, and relates to the technical field of solidified soil. Comprising the following steps: 1, precipitating shield slurry, adding a composite flocculant for precipitation, and extracting floating water to obtain a water-reducing material; 2, mixing the water reducing material with a curing agent, and uniformly stirring to obtain fluid soil; and 3, the fluid soil is pumped, filled and maintained, and the fluid solidified soil is obtained. The shield slurry has the beneficial effects that by adopting the combined effect of flocculation and solidification, the shield slurry is self-compressed and self-compacted, the formation of hydration products is accelerated, the uniformity and compactness of the hydration products are improved, the hydration products can better play a framework role and connect more slurry particles, the flocculation-solidification body structure is more compact, and the stability of the shield slurry is improved. Therefore, the strength and the flowability of the flow-state solidified soil are effectively enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of solidified soil, and in particular to a method for preparing fluidized solidified soil based on waste shield mud. Background Art

[0002] With the rapid development of urban subway and underground engineering construction, shield method has become one of the main methods of tunnel construction. The waste shield mud (shield slag) generated by the shield machine during the excavation process has brought severe environmental and disposal problems. These muds contain a high proportion of fine-grained soil, rock fragments and improved materials added during the construction process. Their properties are complex. If they are directly discharged, they will pollute the environment and occupy a large amount of land resources. The resource utilization of waste shield mud has become an issue that needs to be solved urgently.

[0003] As a new type of geotechnical engineering material, fluidized solidified soil provides a new way to treat shield slag due to its advantages such as local soil excavation, coordinated disposal of solid waste, high fluidity and pumpability. By adding curing agents such as cement, lime or alkali-activated slag to shield slag, it can be converted into fluidized solidified soil with certain strength and stability for foundation treatment, roadbed filling or other engineering applications. However, since flocculation, filter pressing and curing are currently carried out independently, the processing efficiency is low and the energy consumption is high. In addition, adding too much curing agent will pollute the environment.

[0004] Therefore, in order to solve the above problems, the present invention provides a method for preparing fluidized solidified soil based on abandoned shield mud. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing fluidized solidified soil based on abandoned shield slurry, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing fluidized solidified soil based on abandoned shield slurry, comprising the following steps:

[0008] Step 1: sediment the shield slurry, add composite flocculant to reduce water, extract the floating water, and obtain the water-reduced material;

[0009] Step 2: Mix the water-reducing material and the curing agent, stir evenly, and obtain fluidized soil;

[0010] Step 3: Pump the fluidized soil for filling and curing to obtain fluidized solidified soil.

[0011] More optimally: the raw materials of the fluidized solidified soil include the following components: by weight, 100 parts of shield mud, 0.5-0.8 parts of composite flocculant, and 3-5 parts of solidifying agent.

[0012] More optimally: the water content of the shield slurry is 75-85%; the water content of the water-reducing material is 25-35%.

[0013] More optimally: the preparation process of the composite flocculant is: adding polyaluminium ferric chloride and modified bentonite in a mass ratio of (25-30): (10-12) to deionized water in sequence, heating to 80-90°C, stirring for 1-3h, cooling, filtering, drying and grinding to obtain the composite flocculant.

[0014] More optimally: the preparation process of the modified bentonite is:

[0015] S1: Mix bentonite, glycidoxypropyltrimethoxysilane and 70-90wt% ethanol solution, stir evenly, heat to 70-90°C, continue stirring for 40-50min, filter, wash and dry to obtain epoxidized bentonite;

[0016] S2: 5-hexenoic acid and diethylenetriamine were mixed and stirred evenly, and concentrated hydrochloric acid was added dropwise to adjust the pH of the reaction solution to 7, and then isopropanol dissolved with sodium borohydride was added dropwise. After the addition was completed, stirring was continued for 1-2 hours, and suction was filtered to obtain intermediate A;

[0017] S3: Mix epoxidized bentonite, intermediate A and isopropanol, heat to 100-120°C, react for 1-2h, cool, filter, wash and dry to obtain intermediate B;

[0018] S4: Mix the intermediate B with isopropanol, stir for 30-40 minutes, add dimethyl sulfate dropwise, raise the temperature to 50-60°C, react for 2-3 hours, then add chlorooctane dropwise, continue to react for 4-5 hours, filter, wash, and dry to obtain modified bentonite.

[0019] More optimally: the epoxidized bentonite comprises the following components: by weight, 100-120 parts of bentonite, 1-2 parts of glycidoxypropyltrimethoxysilane, and 200-250 parts of ethanol solution;

[0020] The intermediate A comprises the following components: by weight, 10-12 parts of 5-hexenoic acid, 6-8 parts of diethylenetriamine, 1-2 parts of sodium borohydride, and 50-60 parts of isopropanol;

[0021] The intermediate B comprises the following components: by weight, 5-6 parts of epoxidized bentonite, 12-15 parts of intermediate A, and 60-70 parts of isopropanol;

[0022] The modified bentonite comprises the following components: by weight, 10-12 parts of intermediate B, 70-80 parts of isopropanol, 5-8 parts of dimethyl sulfate, and 3-4 parts of chlorooctane.

[0023] More optimally, the raw materials of the curing agent include the following components: by weight, 20-25 parts of cement, 10-12 parts of alkali-activated slag, 4-5 parts of water glass, 20-25 parts of fly ash, 15-20 parts of modified diatomaceous earth, and 0.05-0.1 parts of initiator (azobisisobutyronitrile).

[0024] More optimally: the preparation process of the modified diatomite is: under a protective atmosphere, diatomite and γ-mercaptopropyltrimethoxysilane in a mass ratio of 10:(3-4) are added to deionized water in sequence, stirred evenly, heated to 75-80°C, γ-mercaptopropyltrimethoxysilane is added, stirred at a constant temperature for 1-2 hours, filtered, and dried to obtain modified diatomite.

[0025] More optimally: the process parameters of the curing are: temperature 60-70°C, humidity ≥60%.

[0026] The present invention uses the combined effect of flocculation and solidification to make the shield mud self-compressed and self-compacted, accelerate the formation of hydration products, improve the uniformity and density of hydration products, and enable the hydration products to better play the role of skeleton, connect more mud particles, and make the flocculation-solidification structure more compact, thereby effectively enhancing the strength and fluidity of the fluidized solidified soil. In addition, the combined use of curing agent and composite flocculant also improves the efficiency of shield mud treatment, promotes resource utilization, and reduces environmental impact. The details are as follows:

[0027] First, the modified bentonite in the composite flocculant prepared by the present invention can become the core skeleton of floccules under the action of van der Waals force and electrostatic attraction, and combine with the hydroxyl binding sites on the surface of polyaluminium ferric chloride to form a composite substance, thereby enhancing the flocculation effect. In addition, the modified bentonite has a high specific surface area and ion exchange capacity, and can adsorb suspended particles and ions in water; at the same time, the polymer chain formed by polyaluminium ferric chloride in water can bridge the bentonite to form a larger floc, thereby improving the flocculation effect;

[0028] Secondly, in order to further improve the combined effect of flocculation and solidification, the present invention modifies the surface of bentonite by chemical grafting; wherein the grafted flexible long-chain molecular structure can help the flocculent gel to form a bridge between mud particles, connect the dispersed particles into a larger flocculent body, and allow the curing agent to be more evenly distributed between soil particles; at the same time, the grafted chemical group is a cationic active agent, which can neutralize the negative charge on the surface of soil or mud particles, reduce the repulsive force between particles, and can also work with the hydration product of the curing agent (such as calcium silicate hydrate) to form a network structure; and under the action of the initiator, the terminal olefin can click with the thiol group on the surface of the modified diatomaceous earth, further improving the density of the flocculation-solidification body structure, thereby improving the mechanical properties of the solidified soil. DETAILED DESCRIPTION

[0029] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0030] It should be noted that the following parts are parts by weight, and the purchase manufacturers of all raw materials involved in the present invention are exemplified without any special restrictions: in the following embodiments, diethylenetriamine CAS is 111-40-0, and the purchase manufacturer is Wuhan Jixin Yibang Biotechnology Co., Ltd.; chlorooctane CAS is 111-85-3, and the purchase manufacturer is Wuhan Jixin Yibang Biotechnology Co., Ltd.; glycidoxypropyltrimethoxysilane CAS is 2530-83-8, and the purchase manufacturer is Hengqiao Industry Co., Ltd.

[0031] Embodiment 1: A method for preparing fluidized solidified soil based on abandoned shield slurry, comprising the following steps:

[0032] Step 1: 100 parts of shield slurry are precipitated, 0.5 parts of composite flocculant is added to reduce water, and floating water is extracted to obtain water-reduced material;

[0033] Step 2: Mix the water-reducing material with 3 parts of the curing agent and stir evenly to obtain fluidized soil;

[0034] Step 3: Pump the fluidized soil for filling and curing to obtain fluidized solidified soil.

[0035] Wherein: the raw materials of the curing agent include the following components: by weight, 20 parts of cement, 10 parts of alkali-activated slag, 4 parts of water glass, 20 parts of fly ash, 15 parts of modified diatomaceous earth, and 0.05 parts of initiator (azobisisobutyronitrile);

[0036] The preparation process of the modified diatomite is as follows: under nitrogen, 10 parts of diatomite and 100 parts of deionized water are mixed, stirred, heated to 75° C., 3 parts of γ-mercaptopropyltrimethoxysilane are added, stirred at a constant temperature for 40 minutes, filtered, and dried to obtain the modified diatomite.

[0037] The preparation process of the composite flocculant is as follows: 25 parts of polyaluminium ferric chloride and 10 parts of modified bentonite are added to 80 parts of deionized water, heated to 80°C, stirred for 1 hour, cooled, ultrasonicated for 2 hours, filtered to obtain a solid, dried, and ground to obtain a composite flocculant. The preparation process of the modified bentonite is as follows:

[0038] S1: 100 parts of bentonite, 1 part of glycidoxypropyltrimethoxysilane and 200 parts of 70wt% ethanol solution were mixed, stirred evenly, heated to 70°C, stirred for 40 minutes, filtered, washed and dried to obtain epoxidized bentonite;

[0039] S2: 10 parts of 5-hexenoic acid and 6 parts of diethylenetriamine were mixed and stirred evenly, and concentrated hydrochloric acid was added dropwise to adjust the pH of the reaction solution to 7, and then 1 part of sodium borohydride and 50 parts of isopropanol were added dropwise. After the addition was completed, stirring was continued for 1 hour, and suction was filtered to obtain intermediate A;

[0040] S3: 5 parts of epoxidized bentonite, 12 parts of intermediate A and 60 parts of isopropanol were mixed, heated to 100°C, reacted for 1 hour, cooled, filtered, washed and dried to obtain intermediate B;

[0041] S4: 10 parts of intermediate B were mixed with 70 parts of isopropanol, stirred for 30 minutes, 5 parts of dimethyl sulfate were added dropwise, the temperature was raised to 50°C, the reaction was continued for 2 hours, and then 3 parts of chlorooctane were added dropwise, the reaction was continued for 4 hours, filtered, washed, and dried to obtain modified bentonite.

[0042] Embodiment 2: A method for preparing fluidized solidified soil based on abandoned shield slurry, comprising the following steps:

[0043] Step 1: 100 parts of shield slurry are precipitated, 0.8 parts of composite flocculant is added to reduce water, and floating water is extracted to obtain water-reduced material;

[0044] Step 2: Mix the water-reducing material with 5 parts of the curing agent and stir evenly to obtain fluidized soil;

[0045] Step 3: Pump the fluidized soil for filling and curing to obtain fluidized solidified soil.

[0046] Wherein: the raw materials of the curing agent include the following components: by weight, 25 parts of cement, 12 parts of alkali-activated slag, 5 parts of water glass, 25 parts of fly ash, 20 parts of modified diatomaceous earth, and 0.1 parts of initiator (azobisisobutyronitrile);

[0047] The preparation process of the modified diatomite is as follows: under nitrogen, 12 parts of diatomite and 150 parts of deionized water are mixed, stirred, heated to 80° C., 4 parts of γ-mercaptopropyltrimethoxysilane are added, stirred at a constant temperature for 50 minutes, filtered, and dried to obtain the modified diatomite;

[0048] The preparation process of the composite flocculant is as follows: 30 parts of polyaluminium ferric chloride and 12 parts of modified bentonite are added to 100 parts of deionized water, heated to 90°C, stirred for 3 hours, cooled, ultrasonicated for 3 hours, filtered to obtain a solid, dried, and ground to obtain a composite flocculant. The preparation process of the modified bentonite is as follows:

[0049] S1: 120 parts of bentonite, 2 parts of glycidoxypropyltrimethoxysilane and 250 parts of 90wt% ethanol solution were mixed, stirred evenly, heated to 90°C, stirred for 50 minutes, filtered, washed and dried to obtain epoxidized bentonite;

[0050] S2: 12 parts of 5-hexenoic acid and 8 parts of diethylenetriamine were mixed and stirred evenly, and concentrated hydrochloric acid was added dropwise to adjust the pH of the reaction solution to 7. Then, 2 parts of sodium borohydride and 60 parts of isopropanol were added dropwise. After the addition was completed, stirring was continued for 2 hours, and suction was filtered to obtain intermediate A;

[0051] S3: 6 parts of epoxidized bentonite, 15 parts of intermediate A and 70 parts of isopropanol were mixed, heated to 120°C, reacted for 2 hours, cooled, filtered, washed and dried to obtain intermediate B;

[0052] S4: 12 parts of intermediate B were mixed with 80 parts of isopropanol, stirred for 40 minutes, 8 parts of dimethyl sulfate were added dropwise, the temperature was raised to 60°C, and the reaction was carried out for 3 hours. Then 4 parts of chlorooctane were added dropwise, and the reaction was continued for 5 hours. The mixture was filtered, washed, and dried to obtain modified bentonite.

[0053] Embodiment 3: A method for preparing fluidized solidified soil based on abandoned shield slurry, comprising the following steps:

[0054] Step 1: 100 parts of shield slurry are precipitated, 0.6 parts of composite flocculant is added to reduce water, and floating water is extracted to obtain water-reduced material;

[0055] Step 2: Mix the water-reducing material with 4 parts of the curing agent and stir evenly to obtain fluidized soil;

[0056] Step 3: Pump the fluidized soil for filling and curing to obtain fluidized solidified soil.

[0057] Wherein: the raw materials of the curing agent include the following components: by weight, 22 parts of cement, 11 parts of alkali-activated slag, 4.5 parts of water glass, 22 parts of fly ash, 18 parts of modified diatomaceous earth, and 0.08 parts of initiator (azobisisobutyronitrile);

[0058] The preparation process of the modified diatomite is as follows: under nitrogen, 11 parts of diatomite and 120 parts of deionized water are mixed, stirred, heated to 80° C., 3.5 parts of γ-mercaptopropyltrimethoxysilane are added, stirred at a constant temperature for 45 minutes, filtered, and dried to obtain the modified diatomite;

[0059] The preparation process of the composite flocculant is as follows: 28 parts of polyaluminium ferric chloride and 11 parts of modified bentonite are added to 85 parts of deionized water, heated to 85°C, stirred for 2 hours, cooled, ultrasonicated for 2.5 hours, filtered to obtain a solid, dried, and ground to obtain a composite flocculant;

[0060] The preparation process of the modified bentonite is:

[0061] S1: 110 parts of bentonite, 1.5 parts of glycidoxypropyltrimethoxysilane and 220 parts of 80 wt % ethanol solution were mixed, stirred evenly, heated to 80° C., stirred for 45 min, filtered, washed and dried to obtain epoxidized bentonite;

[0062] S2: 11 parts of 5-hexenoic acid and 7 parts of diethylenetriamine were mixed and stirred evenly, and concentrated hydrochloric acid was added dropwise to adjust the pH of the reaction solution to 7, and then 1.5 parts of sodium borohydride and 55 parts of isopropanol were added dropwise. After the addition was completed, stirring was continued for 1.5 hours, and suction was filtered to obtain intermediate A;

[0063] S3: 5.5 parts of epoxidized bentonite, 13 parts of intermediate A and 65 parts of isopropanol were mixed, heated to 110°C, reacted for 1.5 hours, cooled, filtered, washed and dried to obtain intermediate B;

[0064] S4: 11 parts of intermediate B were mixed with 75 parts of isopropanol, stirred for 35 minutes, 6 parts of dimethyl sulfate were added dropwise, the temperature was raised to 55°C, the reaction was continued for 2.5 hours, and then 3.5 parts of chlorooctane were added dropwise, the reaction was continued for 4.5 hours, filtered, washed, and dried to obtain modified bentonite.

[0065] Comparative Example 1: The bentonite was not modified, and the rest was the same as Example 3, specifically as follows:

[0066] Step 1: 100 parts of shield slurry are precipitated, 0.6 parts of composite flocculant is added to reduce water, and floating water is extracted to obtain water-reduced material;

[0067] Step 2: Mix the water-reducing material with 4 parts of the curing agent and stir evenly to obtain fluidized soil;

[0068] Step 3: Pump the fluidized soil for filling and curing to obtain fluidized solidified soil.

[0069] Wherein: the raw materials of the curing agent include the following components: by weight, 22 parts of cement, 11 parts of alkali-activated slag, 4.5 parts of water glass, 22 parts of fly ash, and 18 parts of modified diatomaceous earth;

[0070] The preparation process of the modified diatomite is as follows: under nitrogen, 11 parts of diatomite and 120 parts of deionized water are mixed, stirred, heated to 80° C., 3.5 parts of γ-mercaptopropyltrimethoxysilane are added, stirred at a constant temperature for 45 minutes, filtered, and dried to obtain the modified diatomite;

[0071] The preparation process of the composite flocculant is as follows: 28 parts of polyaluminium ferric chloride and 11 parts of bentonite are added to 85 parts of deionized water, the temperature is raised to 85°C, stirred for 2 hours, cooled, ultrasonicated for 2.5 hours, filtered to obtain a solid, dried, and ground to obtain the composite flocculant;

[0072] Comparative Example 2: The diatomaceous earth is not modified, and the rest is the same as Example 3, specifically as follows:

[0073] Step 1: 100 parts of shield slurry are precipitated, 0.6 parts of composite flocculant is added to reduce water, and floating water is extracted to obtain water-reduced material;

[0074] Step 2: Mix the water-reducing material with 4 parts of the curing agent and stir evenly to obtain fluidized soil;

[0075] Step 3: Pump the fluidized soil for filling and curing to obtain fluidized solidified soil.

[0076] The raw materials of the curing agent include the following components: by weight, 22 parts of cement, 11 parts of alkali-activated slag, 4.5 parts of water glass, 22 parts of fly ash, and 18 parts of diatomaceous earth;

[0077] The preparation process of the composite flocculant is as follows: 28 parts of polyaluminium ferric chloride and 11 parts of modified bentonite are added to 85 parts of deionized water, heated to 85°C, stirred for 2 hours, cooled, ultrasonicated for 2.5 hours, filtered to obtain a solid, dried, and ground to obtain a composite flocculant;

[0078] The preparation process of the modified bentonite is:

[0079] S1: 110 parts of bentonite, 1.5 parts of glycidoxypropyltrimethoxysilane and 220 parts of 80 wt % ethanol solution were mixed, stirred evenly, heated to 80° C., stirred for 45 min, filtered, washed and dried to obtain epoxidized bentonite;

[0080] S2: 11 parts of 5-hexenoic acid and 7 parts of diethylenetriamine were mixed and stirred evenly, and concentrated hydrochloric acid was added dropwise to adjust the pH of the reaction solution to 7, and then 1.5 parts of sodium borohydride and 55 parts of isopropanol were added dropwise. After the addition was completed, stirring was continued for 1.5 hours, and suction was filtered to obtain intermediate A;

[0081] S3: 5.5 parts of epoxidized bentonite, 13 parts of intermediate A and 65 parts of isopropanol were mixed, heated to 110°C, reacted for 1.5 hours, cooled, filtered, washed and dried to obtain intermediate B;

[0082] S4: 11 parts of intermediate B were mixed with 75 parts of isopropanol, stirred for 35 minutes, 6 parts of dimethyl sulfate were added dropwise, the temperature was raised to 55°C, the reaction was continued for 2.5 hours, and then 3.5 parts of chlorooctane were added dropwise, the reaction was continued for 4.5 hours, filtered, washed, and dried to obtain modified bentonite.

[0083] Comparative Example 3: No bentonite was added, and the rest was the same as Example 3, specifically as follows:

[0084] Step 1: 100 parts of shield slurry are precipitated, 0.6 parts of flocculant is added to reduce water, and floating water is extracted to obtain water-reduced material;

[0085] Step 2: Mix the water-reducing material with 4 parts of the curing agent and stir evenly to obtain fluidized soil;

[0086] Step 3: Pump the fluidized soil for filling and curing to obtain fluidized solidified soil.

[0087] Wherein: the raw materials of the curing agent include the following components: by weight, 22 parts of cement, 11 parts of alkali-activated slag, 4.5 parts of water glass, 22 parts of fly ash, and 18 parts of modified diatomaceous earth;

[0088] The preparation process of the modified diatomite is as follows: under nitrogen, 11 parts of diatomite and 120 parts of deionized water are mixed, stirred, heated to 80° C., 3.5 parts of γ-mercaptopropyltrimethoxysilane are added, stirred at a constant temperature for 45 minutes, filtered, and dried to obtain the modified diatomite;

[0089] The preparation process of the composite flocculant is as follows: 28 parts of polyaluminium ferric chloride are added to 85 parts of deionized water, the temperature is raised to 85°C, stirred for 2 hours, cooled, ultrasonicated for 2.5 hours, filtered to obtain a solid, dried, and ground to obtain a flocculant.

[0090] Test experiment: (1) The fluidized solidified soil obtained in Example 3 and Comparative Examples 1-3 was cured at a temperature of 40°C and a humidity of ≥90%, and the unconfined compressive strength after curing for 7d, 14d, 30d, and 60d was measured with reference to JTG3430-2020. The obtained data are shown in the following table:

[0091]

[0092]

[0093] Table 1

[0094] (2) The fluidized solidified soil obtained in Example 3 and Comparative Examples 1-3 was collapsed on a glass plate, left to stand for 1 min, the maximum diameter was measured and recorded, and it was scraped into a basin with a knife, continued to be stirred, and refilled into a PVC mold, and continued to collapse on a glass plate. The maximum diameter and the length of the vertical part were measured and recorded. The average value was calculated twice to obtain the final fluidity. The obtained data are shown in the following table:

[0095] project Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Fluidity(mm) 198 161 157 155

[0096] Table 2

[0097] Conclusion: Example 3 uses the combined effect of flocculation and solidification to make the shield mud self-compressed and self-compacted, accelerate the formation of hydration products, improve the uniformity and density of hydration products, and enable the hydration products to better play a skeleton role, connect more mud particles, and the flocculation-solidification structure will be more compact, thereby effectively enhancing the strength and fluidity of the fluidized solidified soil. In addition, the combined use of the curing agent and the composite flocculant also improves the efficiency of shield mud treatment, promotes resource utilization, and reduces environmental impact. Comparative Example 1 does not modify the bentonite, so that the cross-linking effect between the flocculant and the curing agent is weakened, and the performance is reduced; Comparative Example 2 does not modify the diatomaceous earth, so that the cross-linking effect between the flocculant and the curing agent is weakened, and the performance is reduced; Comparative Example 3 does not add bentonite, and the flocculant is a single polyaluminum ferric chloride. While the flocculation effect is reduced, the performance of the fluidized solidified soil obtained is also reduced.

[0098] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing fluidized solidified soil based on abandoned shield slurry, characterized in that: The following steps are involved: Step 1: sediment the shield slurry, add composite flocculant to reduce water, extract the floating water, and obtain the water-reduced material; Step 2: Mix the water-reducing material and the curing agent, stir evenly, and obtain fluidized soil; Step 3: Pump the fluidized soil for filling and curing to obtain fluidized solidified soil.

2. The method for preparing fluidized solidified soil based on abandoned shield slurry according to claim 1, characterized in that: The raw materials of the fluidized solidified soil include the following components: by weight, 100 parts of shield mud, 0.5-0.8 parts of composite flocculant, and 3-5 parts of solidifying agent.

3. The method for preparing fluidized solidified soil based on abandoned shield slurry according to claim 1, characterized in that: The water content of the shield mud is 75-85%; the water content of the water-reducing material is 25-35%.

4. The method for preparing fluidized solidified soil based on abandoned shield slurry according to claim 1, characterized in that: The preparation process of the composite flocculant is as follows: polyaluminium chloride ferric and modified bentonite in a mass ratio of (25-30):(10-12) are sequentially added into deionized water, heated to 80-90°C, stirred for 1-3h, cooled, filtered, dried and ground to obtain the composite flocculant.

5. The method for preparing fluidized solidified soil based on abandoned shield slurry according to claim 4, characterized in that: The preparation process of the modified bentonite is: S1: Mix bentonite, glycidoxypropyltrimethoxysilane and 70-90wt% ethanol solution, stir evenly, heat to 70-90°C, continue stirring for 40-50min, filter, wash and dry to obtain epoxidized bentonite; S2: 5-hexenoic acid and diethylenetriamine were mixed and stirred evenly, and concentrated hydrochloric acid was added dropwise to adjust the pH of the reaction solution to 7, and then isopropanol dissolved with sodium borohydride was added dropwise. After the addition was completed, stirring was continued for 1-2 hours, and suction was filtered to obtain intermediate A; S3: Mix epoxidized bentonite, intermediate A and isopropanol, heat to 100-120°C, react for 1-2h, cool, filter, wash and dry to obtain intermediate B; S4: Mix the intermediate B with isopropanol, stir for 30-40 minutes, add dimethyl sulfate dropwise, raise the temperature to 50-60°C, react for 2-3 hours, then add chlorooctane dropwise, continue to react for 4-5 hours, filter, wash, and dry to obtain modified bentonite.

6. The method for preparing fluidized solidified soil based on abandoned shield slurry according to claim 4, characterized in that: The epoxidized bentonite comprises the following components: by weight, 100-120 parts of bentonite, 1-2 parts of glycidoxypropyltrimethoxysilane, and 200-250 parts of ethanol solution; The intermediate A comprises the following components: by weight, 10-12 parts of 5-hexenoic acid, 6-8 parts of diethylenetriamine, 1-2 parts of sodium borohydride, and 50-60 parts of isopropanol; The intermediate B comprises the following components: by weight, 5-6 parts of epoxidized bentonite, 12-15 parts of intermediate A, and 60-70 parts of isopropanol; The modified bentonite comprises the following components: by weight, 10-12 parts of intermediate B, 70-80 parts of isopropanol, 5-8 parts of dimethyl sulfate, and 3-4 parts of chlorooctane.

7. The method for preparing fluidized solidified soil based on abandoned shield slurry according to claim 1, characterized in that: The raw materials of the curing agent include the following components: by weight, 20-25 parts of cement, 10-12 parts of alkali-activated slag, 4-5 parts of water glass, 20-25 parts of fly ash, 15-20 parts of modified diatomaceous earth, and 0.05-0.1 parts of initiator.

8. The method for preparing fluidized solidified soil based on abandoned shield slurry according to claim 3, characterized in that: The preparation process of the modified diatomite is as follows: under a protective atmosphere, diatomite and γ-mercaptopropyltrimethoxysilane in a mass ratio of 10:(3-4) are sequentially added into deionized water, stirred evenly, heated to 75-80° C., γ-mercaptopropyltrimethoxysilane is added, stirred at a constant temperature for 1-2 hours, filtered, and dried to obtain the modified diatomite.

9. The method for preparing fluidized solidified soil based on abandoned shield slurry according to claim 1, characterized in that: The process parameters of the curing are: temperature 60-70° C., humidity ≥ 60%.

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