Treatment-free red-mud-based regenerated flow-state solidified soil suitable for foundation pit backfilling and construction method of treatment-free red-mud-based regenerated flow-state solidified soil

Abstract

The invention relates to the field of solid waste resource utilization research, in particular to treatment-free red mud-based regenerated flow state solidified soil suitable for foundation pit backfill and a construction method thereof, and the treatment-free red mud-based regenerated flow state solidified soil comprises the following components in parts by mass: 100 parts of engineering residue soil, 10-30 parts of red mud compound regenerated micro powder, 50-70 parts of regenerated fine aggregate and 5-10 parts of a water-based activator. The red mud compound regenerated micro powder, the regenerated fine aggregate, the engineering residue soil and the water-based exciting agent are stirred and mixed uniformly in proportion to obtain the treatment-free red mud-based regenerated fluid-state solidified soil suitable for foundation pit backfilling, the red mud does not need to be dried by adopting the fluid-state solidified soil, the construction method is simple, the feasibility is high, and the construction cost is low. The backfilling compactness and strength of the foundation pit can be effectively guaranteed without rolling, post-construction settlement is reduced, a large number of solid waste resources such as red mud and construction waste are utilized, and the good energy-saving and carbon-reducing effects are achieved.

Description

Technical Field

[0001] The invention belongs to the research field of solid waste resource utilization, and specifically relates to a treatment-free red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling and a construction method thereof. Background Art

[0002] With the rapid development of urbanization in my country, urban drainage channels and communication pipelines also need to be upgraded and renovated accordingly. In the process of backfilling foundation pits of various projects, we often encounter problems such as narrow foundation pit backfill space, large backfill depth, unstable backfill soil compaction quality, and high backfill soil quality requirements. Accidents of sinking and damage to building scattered water, pipelines, access roads and other parts due to loose backfill soil, and loss of use functions often occur. At the same time, the foundation pit backfill is limited by backfill conditions, space and other factors and cannot be backfilled densely. The existence of this situation poses a threat to the seismic performance of tall buildings. Traditional processes mostly use plain soil or gray soil in layers using small compaction equipment for construction. The construction is difficult, the backfill period is long, and the quality of the backfill is difficult to control. Therefore, in order to ensure the quality of the backfill, most projects have to use plain concrete for backfilling. The cost of using plain concrete backfill is high, and the high strength brings difficulties to later repairs and maintenance.

[0003] Fluidized solidified soil is a new type of building material specially developed to address the above problems. It makes full use of the foundation soil after excavation or abandonment. After adding a certain proportion of cement and water, it is fully mixed evenly through machinery to form a pumpable and fluid reinforcement material. It is used for backfilling and pouring of various foundation pits, and has a certain strength to reduce the settlement of the roadbed.

[0004] At present, cement is the main cementing material commonly used in fluidized solidified soil. Cement shrinkage and temperature shrinkage are inevitable during the hydration and consolidation process. Therefore, premixed fluidized solidified soil often has crack disease problems. In addition, cement materials are also high-energy consumption and high-emission materials. Every 1t of cement clinker produced will emit 0.894-1.215tCO2. Therefore, it is necessary to find low-carbon cementing materials to replace cement. Researchers began to consider using solid waste materials to replace cement to prepare fluidized solidified soil. Document CN117735937A discloses a method for preparing fluidized soil. The curing agent includes the weight parts of each component: 20-30 parts of calcium carbide slag, 5-10 parts of phosphogypsum, 50-70 parts of fly ash, and 1-3 parts of sodium hydroxide. After mixing 150-200 parts of sludge slurry with 76-113 parts of curing agent, the unconfined compressive strength 7d of high-strength fluidized soil is not less than 2000k Pa.

[0005] At present, there are few reports on the application of red mud and construction solid waste in fluidized soil. In addition, red mud contains a large amount of water, which is just used as the water required for pumping and solidification in fluidized soil. Therefore, the synergistic use of untreated red mud and construction solid waste materials in fluidized soil will have great potential. Summary of the invention

[0006] Based on the problems existing in the prior art, the present invention proposes a treatment-free red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling and a construction method thereof, which can realize the large-scale utilization of treatment-free red mud and construction waste materials, achieve the purpose of solid waste resource utilization, and effectively solve the problem of uneven settlement of foundation pit backfilling, meeting the current trend of technological development.

[0007] The technical solution adopted by the present invention is:

[0008] A treatment-free red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling, comprising the following components in parts by mass:

[0009] 100 pieces of construction waste;

[0010] Red mud mixed with recycled micro powder 10-30 parts;

[0011] 50-70 parts of recycled fine aggregate;

[0012] 5-10 parts of water-based activator;

[0013] The red mud compounded regenerated micro powder, regenerated fine aggregate, engineering slag and water-based activator are stirred and mixed evenly in proportion to obtain the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling.

[0014] Furthermore, the red mud compound regenerated micropowder comprises a mixture of dry-free red mud, regenerated mortar powder and regenerated brick powder.

[0015] Furthermore, the moisture content of the red mud treated without drying is 20%-30%, the mass fraction of SiO2 is greater than 10%, the mass fraction of Al2O3 is greater than 15%, and the mass fraction of Fe2O3 is greater than 20%.

[0016] Furthermore, the water content of the mixture of the non-drying red mud, recycled mortar powder and recycled brick powder is 10%-15%, and the molar ratio of calcium:silicon:aluminum:iron is 0.5-1:0.4-0.8:1-2.5:1-3.

[0017] Furthermore, the gradation composition mass fraction of the recycled fine aggregate is as follows:

[0018] 2.36mm: 90%-100%;

[0019] 1.18mm: 70%-80%;

[0020] 0.6mm: 30%-70%;

[0021] 0.3mm: 15%-40%;

[0022] 0.15mm: 8%-20%;

[0023] 0.075mm: 5%-10%.

[0024] Furthermore, the water-based activator includes sodium silicate, sodium hydroxide, polycarboxylate, acrylic resin, cellulose ether, boric acid and water.

[0025] Furthermore, the water-based exciter comprises the following components in parts by weight:

[0026] 1-3 parts of sodium silicate;

[0027] 2-5 parts of sodium hydroxide;

[0028] 1-4 parts of polycarboxylate;

[0029] Acrylic resin 0.5-1.5 parts;

[0030] 1-2 parts of cellulose ether;

[0031] 1-3 parts of boric acid;

[0032] 1-5 parts water.

[0033] In addition, the present invention also provides a construction method for untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling, comprising the following steps:

[0034] S1. Detecting the components of the red mud treated without drying, including the water content of the red mud treated without drying being 20%-30%, the mass fraction of SiO2 being greater than 10%, the mass fraction of Al2O3 being greater than 15%, and the mass fraction of Fe2O3 being greater than 20%;

[0035] S2. Prepare red mud compound regenerated powder, add regenerated mortar powder and regenerated brick powder while stirring the red mud without drying in an on-site mixing equipment, and adjust the water content in the mixture to 10%-15%, and the molar ratio of calcium: silicon: aluminum: iron is 0.5-1:0.4-0.8:1-2.5:1-3;

[0036] S3. Prepare a water-based activator, weigh and mix 1-3 parts of sodium silicate, 2-5 parts of sodium hydroxide, 1-4 parts of polycarboxylate, 0.5-1.5 parts of acrylic resin, 1-2 parts of cellulose ether, 1-3 parts of boric acid and 1-5 parts of water, and add 5-10 parts of it to 10-30 parts of the red mud compound regenerated micropowder in step S2 to obtain a highly fluid red mud compound regenerated micropowder gelling material;

[0037] S4. 100 parts of the construction slag are added to the highly fluid red mud compounded regenerated micro-powder cementitious material in step S3 and mixed evenly to obtain a mixture; the construction slag includes sandy soil, silty clay and sub-silty clay;

[0038] S5. Add 50-70 parts of recycled fine aggregate with a gradation of 2.36mm: 90%-100%; 1.18mm: 70%-80%; 0.6mm: 30%-70%; 0.3mm: 15%-40%; 0.15mm: 8%-20%; 0.075mm: 5%-10% to the mixed material of step S4, mix for 5-10 minutes at a mixing rate of 100-200 rpm, and obtain untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling, and test its quality to meet the fluidity and strength requirements.

[0039] The untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling has a fluidity of 230 mm to 400 mm and a 3-day compressive strength of not less than 1 MPa.

[0040] The red mud compound regenerated micro powder of the present invention adjusts the molar ratio and water content of calcium, silicon, aluminum and iron in the red mud through regenerated mortar powder and regenerated brick powder; the regenerated fine aggregate adjusts the compactness of the engineering slag through the grading composition, and the water-based activator activates the activity of the red mud compound regenerated micro powder cementitious material at room temperature. The red mud compound regenerated micro powder, water-based activator, engineering slag and regenerated fine aggregate are stirred and mixed evenly in proportion to obtain the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling. The fluidized solidified soil of the present invention does not require drying of the red mud, the construction method is simple, and the feasibility is strong. The compactness and strength of the foundation pit backfill can be effectively guaranteed without rolling, and the post-construction settlement can be reduced. In addition, a large amount of solid waste resources such as red mud and construction waste are utilized, which has a good effect of energy saving and carbon reduction.

[0041] The beneficial effects produced by the present invention are as follows:

[0042] (1) The untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling and the construction method thereof of the present invention is a brand-new low-carbon and environmentally friendly foundation pit backfilling material and technology, which can make large-scale use of construction solid waste concrete and industrial solid waste red mud, reduce the accumulation and land occupation of these two types of solid waste materials, and realize the resource utilization of solid waste;

[0043] (2) It effectively solves the problem of efficient and convenient utilization of red mud. There is no need to perform additional drying treatment on the red mud. The water in the red mud can be used to solidify the fluidized soil, thus reducing the cost and water pollution problems in red mud treatment.

[0044] (3) The problem of uneven settlement of foundation pit backfill was effectively solved. The fluidity of the red mud-based regenerated fluidized solidified soil was 230mm-400mm, which ensured the compactness of the foundation pit backfill. The 3-day compressive strength was not less than 1MPa, which ensured the strength of the foundation pit backfill. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a construction rendering of the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling in Example 4 of the present invention. DETAILED DESCRIPTION

[0046] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0047] Example 1

[0048] The present embodiment 1 is a kind of untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling, which includes the following components in mass fractions: 100 parts of construction waste soil; 10 parts of red mud compounded regenerated micro powder; 50 parts of regenerated fine aggregate; and 5 parts of water-based activator.

[0049] Red mud compound recycled micro powder is a mixture of red mud that does not require drying, recycled mortar powder and recycled brick powder.

[0050] The moisture content of the red mud treated without drying is 20%, the mass fraction of SiO2 is 16%, the mass fraction of Al2O3 is 25%, and the mass fraction of Fe2O3 is 28%.

[0051] The water content of the mixture of the non-drying red mud, the recycled mortar powder and the recycled brick powder is 10%, and the molar ratio of calcium: silicon: aluminum: iron is 0.5:0.4:1:1.

[0052] The gradation composition mass fractions of the recycled fine aggregate components are as follows: 2.36mm: 90%; 1.18mm: 70%; 0.6mm: 30%; 0.3mm: 15%; 0.15mm: 8%; 0.075mm: 5%.

[0053] The water-based activator component is sodium silicate, sodium hydroxide, polycarboxylate, acrylic resin, cellulose ether, boric acid and water. The mass fractions of the water-based activator component are as follows: 1 part of sodium silicate; 2 parts of sodium hydroxide; 1 part of polycarboxylate; 0.5 part of acrylic resin; 1 part of cellulose ether; 1 part of boric acid; and 1 part of water.

[0054] In order to prepare the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfill, the following preparation steps are adopted:

[0055] S1. Detect the components of the red mud treated without drying. The water content of the red mud treated without drying is 20%, the mass fraction of SiO2 is 16%, the mass fraction of Al2O3 is 25%, and the mass fraction of Fe2O3 is 28%;

[0056] S2. Preparation of red mud composite regenerated powder, adding regenerated mortar powder and regenerated brick powder while stirring the red mud without drying in an on-site mixing equipment, adjusting the water content in the mixture to 10%, and the molar ratio of calcium: silicon: aluminum: iron to 0.5:0.4:1:1;

[0057] S3. Prepare a water-based activator, weigh and mix 1 part of sodium silicate, 2 parts of sodium hydroxide, 1 part of polycarboxylate, 0.5 parts of acrylic resin, 1 part of cellulose ether, 1 part of boric acid and 1 part of water, and add 5 parts of the water-based activator to 10 parts of the red mud compound regenerated micropowder in step S2 to obtain a highly fluid red mud compound regenerated micropowder gelling material;

[0058] S4. 100 parts of the construction slag are added to the highly fluid red mud compounded regenerated micro-powder cementitious material in step S3 and mixed evenly to obtain a mixture; the construction slag is sandy soil, silty clay and sub-silty clay;

[0059] S5. Add 50 parts of recycled fine aggregate with a graded composition of 2.36mm: 90%; 1.18mm: 70%; 0.6mm: 30%; 0.3mm: 15%; 0.15mm: 8%; 0.075mm: 5% to the mixed material of step S4, and mix for 5 minutes at a mixing rate of 100 rpm to obtain red mud-based regenerated fluidized solidified soil, and test its fluidity and strength as shown in Table 1.

[0060] Table 1 Test results of properties of untreated red mud-based regenerated fluidized solidified soil

[0061] Detection indicators Test Results Index requirements Fluidity 255mm 230mm-400mm 3d compressive strength 2.45MPa ≥1MPa

[0062] Example 2

[0063] The second embodiment of the present invention is a kind of untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling, which includes the following components in mass fractions: 100 parts of construction waste soil; 30 parts of red mud compounded regenerated micro powder; 70 parts of regenerated fine aggregate; and 10 parts of water-based activator.

[0064] Red mud compound recycled micro powder is a mixture of red mud that does not require drying, recycled mortar powder and recycled brick powder.

[0065] The water content of the red mud treated without drying is 30%, the mass fraction of SiO2 is 24%, the mass fraction of Al2O3 is 35%, and the mass fraction of Fe2O3 is 32%.

[0066] The water content of the mixture of the non-drying red mud, the recycled mortar powder and the recycled brick powder is 15%, and the molar ratio of calcium: silicon: aluminum: iron is 1:0.8:2.5:3.

[0067] The gradation composition mass fractions of the recycled fine aggregate components are as follows: 2.36mm: 100%; 1.18mm: 80%; 0.6mm: 70%; 0.3mm: 40%; 0.15mm: 20%; 0.075mm: 10%.

[0068] The water-based activator component is sodium silicate, sodium hydroxide, polycarboxylate, acrylic resin, cellulose ether, boric acid and water. The mass fraction of the water-based activator component is as follows: 3 parts of sodium silicate; 5 parts of sodium hydroxide; 4 parts of polycarboxylate; 1.5 parts of acrylic resin; 2 parts of cellulose ether; 3 parts of boric acid; 5 parts of water.

[0069] In order to prepare the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfill, the following preparation steps are adopted:

[0070] S1. Detect the components of the red mud treated without drying. The water content of the red mud treated without drying is 30%, the mass fraction of SiO2 is 24%, the mass fraction of Al2O3 is 35%, and the mass fraction of Fe2O3 is 32%;

[0071] S2. Prepare red mud compound regenerated powder, add regenerated mortar powder and regenerated brick powder while stirring the red mud without drying in an on-site mixing equipment, adjust the water content in the mixture to 15%, and the molar ratio of calcium: silicon: aluminum: iron is 1:0.8:2.5:3;

[0072] S3. Prepare a water-based activator, weigh and mix 3 parts of sodium silicate; 5 parts of sodium hydroxide; 4 parts of polycarboxylate; 1.5 parts of acrylic resin; 2 parts of cellulose ether; 3 parts of boric acid and 5 parts of water, and add 10 parts of the water-based activator to 30 parts of the red mud compounded regenerated micropowder in step S2 to obtain a highly fluid red mud compounded regenerated micropowder gelling material;

[0073] S4. 100 parts of the construction slag are added to the highly fluid red mud compounded regenerated micro-powder cementitious material in step S3 and mixed evenly to obtain a mixture; the construction slag is sandy soil, silty clay and sub-silty clay;

[0074] S5. Add 70 parts of recycled fine aggregate with a gradation of 2.36mm: 100%; 1.18mm: 80%; 0.6mm: 70%; 0.3mm: 40%; 0.15mm: 20%; 0.075mm: 10% to the mixed material of step S4, and mix for 10 minutes at a mixing rate of 200 rpm to obtain red mud-based regenerated fluidized solidified soil, and test its fluidity and strength as shown in Table 2.

[0075] Table 2 Test results of properties of untreated red mud-based regenerated fluidized solidified soil

[0076] Detection indicators Test Results Index requirements Fluidity 385mm 230mm-400mm 3d compressive strength 1.85MPa ≥1MPa

[0077] Example 3

[0078] The third embodiment of the present invention is a kind of untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling, which includes the following components in parts by weight: 100 parts of construction waste soil; 15 parts of red mud compounded regenerated micro powder; 56 parts of regenerated fine aggregate; and 5 parts of water-based activator.

[0079] Red mud compound recycled micro powder is a mixture of red mud that does not require drying, recycled mortar powder and recycled brick powder.

[0080] The water content of the red mud treated without drying is 22%, the mass fraction of SiO2 is 15%, the mass fraction of Al2O3 is 18%, and the mass fraction of Fe2O3 is 23%.

[0081] The water content of the mixture of the non-drying red mud, the recycled mortar powder and the recycled brick powder is 12%, and the molar ratio of calcium: silicon: aluminum: iron is 0.5:0.4:1.2:1.5.

[0082] The gradation composition mass fractions of recycled fine aggregate are as follows: 2.36mm: 95%; 1.18mm: 75%; 0.6mm: 36%; 0.3mm: 18%; 0.15mm: 8%; 0.075mm: 5%.

[0083] The water-based activator components are sodium silicate, sodium hydroxide, polycarboxylate, acrylic resin, cellulose ether, boric acid and water. The mass fractions of the components are as follows: 1 part of sodium silicate, 2 parts of sodium hydroxide, 1 part of polycarboxylate, 0.5 parts of acrylic resin, 1 part of cellulose ether, 1 part of boric acid and 3 parts of water.

[0084] The preparation steps of Example 2 were used to prepare the above-mentioned untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling of Example 3. The difference was that the above-mentioned components and proportions of Example 3 were used.

[0085] In order to detect the quality of the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling in Example 3, its fluidity and strength were tested respectively, and the results are shown in Table 3.

[0086] Table 3 Test results of properties of untreated red mud-based regenerated fluidized solidified soil

[0087]

[0088]

[0089] It can be found that all performance tests of the prepared untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling can meet the technical index requirements. The obtained fluidity is 375mm, which can ensure the compactness of the foundation pit backfill. The obtained 3d compressive strength is 1.58MPa, which can effectively ensure the backfill strength of the foundation pit and solve the problem of uneven settlement of the backfill foundation pit.

[0090] Example 4

[0091] The present embodiment 4 is a kind of untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling, which includes the following components in parts by weight: 100 parts of construction waste soil; 25 parts of red mud compounded regenerated micro powder; 65 parts of regenerated fine aggregate; and 8 parts of water-based activator.

[0092] Red mud compound recycled micro powder is a mixture of red mud that does not require drying, recycled mortar powder and recycled brick powder.

[0093] The moisture content of the red mud without drying treatment is 24%, the mass fraction of SiO2 is 18%, the mass fraction of Al2O3 is 25%, and the mass fraction of Fe2O3 is 27%.

[0094] The water content of the mixture of the non-drying red mud, the recycled mortar powder and the recycled brick powder is 12%, and the molar ratio of calcium: silicon: aluminum: iron is 0.8:0.6:1.7:2.

[0095] The grading composition mass fractions of recycled fine aggregate are as follows: 2.36mm: 90%; 1.18mm: 72%; 0.6mm: 43%; 0.3mm: 25%; 0.15mm: 12%; 0.075mm: 7%.

[0096] The water-based activator components are sodium silicate, sodium hydroxide, polycarboxylate, acrylic resin, cellulose ether, boric acid and water. The mass fractions of each component are as follows: 1.5 parts of sodium silicate, 2.8 parts of sodium hydroxide, 2.5 parts of polycarboxylate, 1.3 parts of acrylic resin, 2 parts of cellulose ether, 2 parts of boric acid and 1 part of water.

[0097] The preparation steps of Example 2 were used to prepare the above-mentioned untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling of Example 4. The difference was that the above-mentioned components and proportions of Example 4 were used.

[0098] In order to detect the quality of the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling in Example 4, its fluidity and strength were tested respectively, and the results are shown in Table 4.

[0099] Table 4 Test results of properties of untreated red mud-based regenerated fluidized solidified soil

[0100] Detection indicators Test Results Index requirements Fluidity 273mm 230mm-400mm 3d compressive strength 2.34MPa ≥1MPa

[0101] It can be found that all performance tests of the prepared untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling can meet the technical index requirements.

[0102] In addition, in order to verify the engineering application effect of the treatment-free red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling of the present invention, a construction application is carried out in combination with a physical project, including the following steps:

[0103] ① The components of the red mud treated without drying were detected. The water content, SiO2 mass fraction, Al2O3 mass fraction and Fe2O3 mass fraction in the red mud treated without drying were 24%, 18%, 25% and 27% respectively.

[0104] ② Prepare red mud compound regenerated micro powder, add regenerated mortar powder and regenerated brick powder while stirring the red mud without drying in the on-site mixing equipment, and adjust the water content in the mixture to 12%, and the molar ratio of calcium: silicon: aluminum: iron to 0.8:0.6:1.7:2;

[0105] ③ Prepare a water-based activator, weigh and mix 1.5 parts of sodium silicate, 2.8 parts of sodium hydroxide, 2.5 parts of polycarboxylate, 1.3 parts of acrylic resin, 2 parts of cellulose ether, 2 parts of boric acid and 1 part of water, and add 8 parts of the water-based activator to 25 parts of the red mud compound regenerated micropowder in step ② to obtain a highly fluid red mud compound regenerated micropowder gelling material;

[0106] ④ Add 100 parts of the construction slag to the highly fluid red mud compounded regenerated micro-powder cementitious material in step ③ and mix them evenly to obtain a mixture; the construction slag is sandy soil, silty clay and sub-silty clay;

[0107] ⑤ Add 65 parts of recycled fine aggregate with the gradation of 2.36mm: 90%; 1.18mm: 72%; 0.6mm: 43%; 0.3mm: 25%; 0.15mm: 12%; 0.075mm: 7% to the mixed material in step ④, and mix for 10 minutes at a mixing rate of 200 rpm to obtain the red mud-based regenerated fluidized solidified soil without drying treatment. After testing its quality to meet the fluidity and strength requirements, pump it into the foundation pit for filling. The effect of the foundation pit after filling for 3 days is as follows: Figure 1 shown.

[0108] Judging from the results of the implementation of the test section project, the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling of the present invention can effectively solve the problem of uneven settlement of foundation pit backfilling, and a large amount of solid waste materials such as untreated red mud and construction waste concrete are used, which is convenient to construct, has strong feasibility, and has significant economic, social and environmental benefits.

[0109] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A treatment-free red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling, characterized in that: The composition includes the following components in parts by weight: 100 pieces of construction waste; Red mud mixed with recycled micro powder 10-30 parts; 50-70 parts of recycled fine aggregate; 5-10 parts of water-based activator; The red mud compounded regenerated micro powder, regenerated fine aggregate, engineering slag and water-based activator are stirred and mixed evenly in proportion to obtain the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling.

2. The untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling according to claim 1, characterized in that: The red mud compound regenerated micro powder comprises a mixture of dry-free red mud, regenerated mortar powder and regenerated brick powder.

3. The untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling according to claim 2, characterized in that: The water content of the red mud treated without drying is 20%-30%, the mass fraction of SiO2 is greater than 10%, the mass fraction of Al2O3 is greater than 15%, and the mass fraction of Fe2O3 is greater than 20%.

4. The untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling according to claim 2, characterized in that: The water content of the mixture of the non-drying red mud, the recycled mortar powder and the recycled brick powder is 10%-15%, and the molar ratio of calcium: silicon: aluminum: iron is 0.5-1:0.4-0.8:1-2.5:1-3.

5. The untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling according to claim 1, characterized in that: The gradation composition mass fraction of the recycled fine aggregate is as follows: 2.36mm: 90%-100%; 1.18mm: 70%-80%; 0.6mm: 30%-70%; 0.3mm: 15%-40%; 0.15mm: 8%-20%; 0.075mm: 5%-10%.

6. The untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling according to claim 1, characterized in that: The water-based activator comprises sodium silicate, sodium hydroxide, polycarboxylate, acrylic resin, cellulose ether, boric acid and water.

7. The untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling according to claim 1, characterized in that: The water-based exciter comprises the following components in parts by weight: 1-3 parts of sodium silicate; 2-5 parts of sodium hydroxide; 1-4 parts of polycarboxylate; Acrylic resin 0.5-1.5 parts; 1-2 parts of cellulose ether; 1-3 parts of boric acid; 1-5 parts water.

8. A construction method for untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Detecting the components of the red mud treated without drying, including the water content of the red mud treated without drying being 20%-30%, the mass fraction of SiO2 being greater than 10%, the mass fraction of Al2O3 being greater than 15%, and the mass fraction of Fe2O3 being greater than 20%; S2. Prepare red mud compound regenerated powder, add regenerated mortar powder and regenerated brick powder while stirring the red mud without drying in an on-site mixing equipment, and adjust the water content in the mixture to 10%-15%, and the molar ratio of calcium: silicon: aluminum: iron is 0.5-1:0.4-0.8:1-2.5:1-3; S3. Prepare a water-based activator, weigh and mix 1-3 parts of sodium silicate, 2-5 parts of sodium hydroxide, 1-4 parts of polycarboxylate, 0.5-1.5 parts of acrylic resin, 1-2 parts of cellulose ether, 1-3 parts of boric acid and 1-5 parts of water, and add 5-10 parts of it to 10-30 parts of the red mud compound regenerated micropowder in step S2 to obtain a highly fluid red mud compound regenerated micropowder gelling material; S4. 100 parts of the construction slag are added to the highly fluid red mud compounded regenerated micro-powder cementitious material in step S3 and mixed evenly to obtain a mixture; the construction slag includes sandy soil, silty clay and sub-silty clay; S5. Add 50-70 parts of recycled fine aggregate with a gradation of 2.36mm: 90%-100%; 1.18mm: 70%-80%; 0.6mm: 30%-70%; 0.3mm: 15%-40%; 0.15mm: 8%-20%; 0.075mm: 5%-10% to the mixed material of step S4, mix for 5-10 minutes at a mixing rate of 100-200 rpm, and obtain untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling, and test its quality to meet the fluidity and strength requirements.

9. The construction method of the untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfilling according to claim 8, characterized in that: The untreated red mud-based regenerated fluidized solidified soil suitable for foundation pit backfill has a fluidity of 230 mm to 400 mm and a 3-day compressive strength of not less than 1 MPa.

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