Geopolymer solidification engineering muck and mix proportion design method thereof

Abstract

The invention relates to the technical field of geopolymers, in particular to geopolymer curing engineering muck and a mix proportion design method thereof, and the geopolymer curing engineering muck is prepared by the following method: (1) preparing raw materials including engineering muck, blast furnace slag, fly ash and sodium metasilicate; (2) mixing blast furnace slag and fly ash in proportion, and stirring with sodium metasilicate to obtain a dry material; (3) putting the engineering residue soil into a stirrer, adding the dry material, stirring, slowly adding water, and uniformly mixing and stirring; (4) putting the mixture into a sealing bag, exhausting air, and sealing for 24 hours; and (5) compacting and molding the covered solidified soil, and curing to obtain the geopolymer solidified engineering muck. According to the invention, two groups of orthogonal tests and two times of optimization are carried out, and the final optimal proportion not only meets the early strength so that the test block in 28 days is not easy to crack due to insufficient early strength, but also meets the later compression resistance and tensile strength, and solves the systematic problem of geopolymer mix proportion design.

Description

Technical Field

[0001] The present invention relates to the technical field of geopolymers, and more particularly to a method for designing the mix proportion of geopolymer-solidified engineering muck. Background Art

[0002] Geopolymer is a promising new non-cementitious binder that has attracted much attention internationally. The concept of geopolymer was first proposed in 1978 by Professor Joseph Davidovits, who attempted to use materials rich in silicon-aluminum compounds to prepare high-refractory building materials. Its essence is to undergo depolymerization and polycondensation reactions under the excitation of strong alkalis to obtain a dense three-dimensional network structure. Externally, it is similar to cementitious materials with a certain fluidity and has high strength after hardening.

[0003] Due to the special raw materials and reaction mechanism of geopolymers, there is currently little research on the mix proportion design of geopolymer concrete. Generally, it is to study the influence of the ratio of elements contained in the raw materials on mechanical properties such as strength, and it is also necessary to conduct a large number of tests or use statistical test methods to establish the relationship between concrete performance and components for the design of geopolymer concrete. However, the sources of geopolymer materials are extensive, mainly using solid waste materials. Due to the variety of solid waste materials and the different conditions during their discharge, the chemical composition of each material may be affected. Therefore, even with the same activator and the same curing method, the final performance of geopolymer concrete will vary greatly. The special raw materials and reaction mechanism of geopolymers result in the lack of universality of the above mix proportion design methods. So far, there is still a lack of a unified design method and standard for the mix proportion design of geopolymer concrete.

[0004] Orthogonal experiment is a test method for studying multiple factors and multiple levels. It selects some representative points from the comprehensive experiment according to orthogonality. These representative points have the characteristics of "even dispersion and neat comparability"; through orthogonal experiments, it is beneficial to reduce the number of experiments and can efficiently, quickly, and economically select the better levels of each factor. Summary of the Invention

[0005] Based on the above background, the purpose of the present invention is to provide a method for designing the mix proportion of geopolymer-solidified engineering muck, so as to solve the problem of the lack of a unified method and standard for the mix proportion design of geopolymer concrete.

[0006] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] A method for designing the mix proportion of geopolymer-solidified engineering muck, the method comprising the following steps:

[0008] Step 1: Determine the optimal moisture content and the maximum dry density of the soil through the liquid-plastic limit test and the compaction test of the soil.

[0009] Step 2: Initially select the components of the geopolymer according to the engineering requirements, including the initial mix ratios of the soil, the waste solid content, the alkali activator content, and water. The range of the initially selected mix ratios of the components of the geopolymer is as follows: based on the total weight of the soil and the curing agent being 100%, the waste solid content is 8% - 14%, the alkali activator content is calculated based on the Na2O content accounting for 6% - 12% of the mass of the curing agent, and the waste solid ratio is the mass ratio of fly ash to blast furnace slag being 6:4 to 9:1.

[0010] The curing agent refers to the waste solid and the alkali activator, and the waste solid refers to fly ash and slag.

[0011] Step 3: Establish the first orthogonal test table, with the waste solid content, the alkali activator content, and the waste solid ratio as three factors, and set multiple levels for each factor.

[0012] Step 4: Prepare specimens according to the first orthogonal test table, prepare the geopolymer-solidified engineering soil, and conduct the unconfined compressive strength test after curing for 7 days.

[0013] Step 5: Conduct a range analysis on the test results, determine the influence degree of each factor on the strength, and select the mix ratio range with appropriate early strength.

[0014] Step 6: Establish the second orthogonal test table, and further optimize the mix ratio design based on the mix ratio range determined in Step 5.

[0015] Step 7: Prepare specimens according to the second orthogonal test table, prepare the geopolymer-solidified engineering soil, and conduct the unconfined compressive strength test and the splitting strength test after curing for 28 days.

[0016] Step 8: Determine the final mix ratio of the geopolymer-solidified engineering soil according to the test results of the 28-day unconfined compressive strength and the splitting strength test.

[0017] Through this two-stage orthogonal test optimization design method, the number of tests can be effectively reduced. At the same time, it not only ensures the early strength but also meets the requirements of the later mechanical properties, providing a scientific basis for engineering applications.

[0018] Preferably, in Step 1, initially estimate the optimal moisture content of the soil from the liquid-plastic limit of the soil, select two groups above and below the initially estimated optimal moisture content for the soil compaction test, and determine the optimal moisture content of the soil from the compaction curve. In the later stage, the solidified soil is prepared at a unified moisture content to reduce the test quantity. This method can quickly and accurately determine the optimal moisture content of the engineering soil, and significantly reduce the variables by unifying the moisture content, improving the test efficiency.

[0019] Preferably, in step two, the solid waste content is taken as 8%, 10%, 12%, 14%; the content of the alkali activator is replaced by the percentage of the content of Na2O in the solidifying agent in terms of mass for convenient calculation, and its range is taken as 6%, 8%, 10%, 12%; the solid waste ratio refers to the ratio of fly ash to blast furnace slag, which is taken as: 9:1, 8:2, 7:3, 6:4. This design covers a reasonable range of material ratios. At the same time, the calculation method using the Na2O content is more scientific and intuitive, facilitating the batching calculation in practical engineering applications.

[0020] Preferably, the first orthogonal test table is for three factors and four levels, with a total of 16 groups of tests; the second orthogonal test table is for three factors and three levels, with a total of 9 groups of tests. Each group of tests is designed with 6 groups of parallel tests, and every 6 groups are prepared simultaneously to reduce the test volume; commercially available powder solidifying agents and cement are designed as the control group; regularly check the curing situation, remake the specimens with efflorescence and the specimens with cracks to reduce the errors caused by test operations; conduct a range analysis of the data in the first orthogonal test table using SPSSAU, obtain the mean value broken line graph of the same factor at different levels, optimize 3 groups of optimization intervals, and establish the second orthogonal test table again; the 3 optimized groups of intervals meet the 7-day early strength requirements, conduct 28-day unconfined and splitting strength tests on them, and finally optimize the optimal ratio that meets the early strength, as well as the later compressive and tensile strengths. This design method is scientific and systematic. The reliability of the results is improved through parallel tests. Setting up the control group helps to evaluate the advantages of the scheme, and the optimization efficiency is improved through data visualization analysis.

[0021] Preferably, the specific steps for preparing geopolymer solidified engineering soil in step four include:

[0022] (1) Weigh a certain amount of soil, alkali activator, solid waste (fly ash and blast furnace slag), and water respectively;

[0023] (2) Mix and stir the solid waste and the alkali activator to obtain dry materials;

[0024] (3) Place the engineering soil in a mixer, add the dry materials and stir, while slowly adding water, and mix and stir until uniform; (4) Put the mixture into a sealed bag to remove air and conduct material retting for 24 hours;

[0025] (5) Place the retted solidified soil in a test mold, compact and form it, and conduct curing after demolding.

[0026] This preparation process is simple and practical. The full contact between the alkali activator and the solid waste materials is ensured through the pre-mixing of the dry materials, and the retting process promotes the initial hydration reaction, which is beneficial to improving the strength and stability of the solidified soil.

[0027] Preferably, the method of range analysis in step five is to calculate the average strength values of different levels of each factor and draw the effect curve of the influence of each factor on strength. This data analysis method is intuitive and clear, can clearly show the influence degree and trend of each factor on strength, and provides a scientific basis for optimizing the ratio.

[0028] A geopolymer solidified engineering soil residue is prepared by the following method:

[0029] (1) Prepare raw materials, including engineering soil residue, blast furnace slag, fly ash and sodium metasilicate;

[0030] (2) Mix blast furnace slag and fly ash in proportion, and stir with sodium metasilicate to obtain dry materials;

[0031] (3) Place the engineering soil residue in a mixer, add the dry materials and stir, while slowly adding water, and mix and stir until uniform; (4) Put the mixture into a sealed bag to remove air and carry out material curing for 24 hours;

[0032] (5) Compact and mold the cured soil after curing to obtain the geopolymer solidified engineering soil residue.

[0033] This method is easy to operate, can be implemented on site, is especially suitable for engineering applications, and the materials used are all industrial solid wastes, with high resource utilization value.

[0034] Preferably, this method uses blast furnace slag and fly ash as cementitious materials and sodium metasilicate as an alkali activator to solidify engineering soil residue. The chemical components of blast furnace slag in the cementitious materials are: SiO2, 34.17, CaO, 33.29, Al2O3, 17.86, MgO, 10.62, Fe2O3, 0.31, Na2O, 0.44, SO3, 1.88; the chemical components of fly ash are: SiO2, 49.81, CaO, 2.96, Al2O3, 38.48, MgO, 0.82, Fe2O3, 3.95, Na2O, 0.39, SO3, 0.65; the modulus of the alkali activator is 1.0. This material combination makes full use of the characteristics of high CaO content in blast furnace slag and high SiO2 and Al2O3 contents in fly ash. The two complement each other and can play a better solidification effect as cementitious materials together, ensuring both early strength and long-term stability.

[0035] Preferably, the sodium metasilicate is in powder form with a modulus of 1.0; the solid waste content is 12%, and the ratio of fly ash to blast furnace slag is 0.6 - 0.7; the dosage of the sodium metasilicate is calculated based on the Na2O content accounting for 10% - 12% of the total mass of the curing agent. Using sodium metasilicate in powder form as the alkali activator has the advantages of convenient storage, transportation, and use, and the activation effect is best when the modulus is 1.0; the mass ratio range of blast furnace slag to fly ash ensures the balance between cost and performance, and the Na2O content range ensures sufficient alkali activation effect.

[0036] Preferably, the curing condition in step (5) is: humidity 95%, temperature 20 ± 5°C. This curing condition simulates the actual engineering environment, is suitable for the geopolymer hydration reaction to proceed, and can ensure the stable development of the properties of the solidified soil.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] 1. The present invention conducts two groups of orthogonal experiments and two optimizations. The final optimized ratio not only meets the early strength so that the 28-day test blocks are not prone to cracking due to insufficient early strength but also meets the later compressive and tensile strengths, solving the systematic problem of the geopolymer mix design.

[0039] 2. The present invention uses the mass ratio of Na2O in the curing agent instead of the dosage of the alkali activator, which is more convenient to calculate and is suitable for on-site engineering applications, improving the practicality of the method.

[0040] 3. The present invention uses SPSSAU to obtain a line graph of the means of the same factor at different levels from the orthogonal experiment results, finds the optimal level values under each factor, and the data results are more intuitive and the optimization process is more scientific.

[0041] 4. The present invention uses sodium metasilicate powder activator, which is convenient for storage, transportation, and utilization in actual engineering applications, solving the inconvenience of using liquid alkali activators on-site in engineering. Description of the Drawings

[0042] Figure 1 It is a flowchart of a method for designing the mix ratio of geopolymer solidified engineering muck;

[0043] Figure 2 It is an image of the compressive strength effect curve of the solid waste content;

[0044] Figure 3 It is an image of the compressive strength effect curve of the alkali activation;

[0045] Figure 4 It is a graph of the compressive strength effect curve of the solid waste ratio. Detailed Embodiments

[0046] The technical solution of the present invention will be further specifically described below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any formal modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0047] In the present invention, unless otherwise specified, all parts and percentages are in weight units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments are conventional methods in the art unless otherwise specified.

[0048] In this article, the solid waste content refers to the proportion calculated based on the total weight of the soil body and the solidifying agent being 100%, and the alkali activator content is replaced by the percentage of the content of Na2O in the solidifying agent. The solidifying agent refers to the solid waste and the alkali activator, where the solid waste refers to fly ash and slag, and the alkali activator is sodium metasilicate, all of which are commercially available products.

[0049] A geopolymer provided in this embodiment, the raw materials for preparing the geopolymer include: a test soil sample, from the engineering soil in Yuhang District, Hangzhou. First, it is baked in an oven at 95°C for 12 hours, and then crushed with a crusher. The fine soil passing through a 2.5-mm standard geotechnical sieve is used as the test soil. A gel material composed of blast furnace slag and fly ash, an alkali activator, and water; the alkali activator is sodium metasilicate, and the modulus of water glass in the alkali activator is 1.0; the control group is the product of Hangzhou Guqiang New Materials Co., Ltd. and ordinary Portland cement.

[0050] The main chemical compositions of the raw materials are shown in Table 1 by XRF.

[0051] Table 1 Oxide components and basic contents

[0052]

[0053] In this embodiment, the fly ash has relatively high contents of SiO2 and Al2O3 and relatively low content of CaO; the blast furnace slag has relatively high contents of SiO2 and CaO and relatively low content of Al2O3; therefore, due to the particularity of their compositions, there are defects when using fly ash or blast furnace slag alone as the gel material of the geopolymer. Because when using fly ash alone as the cementitious material, the hydration of the geopolymerized soil produced is slow due to the high contents of SiO2 and Al2O3, resulting in low early strength of the test block and early cracking, and it needs to be cured for a long time to complete hydration; while when using blast furnace slag alone as the cementitious material to make the geopolymerized soil, due to the high content of CaO in the blast furnace slag, the hydration reaction process is fast, and there will also be relatively large pores and cracks during curing, and the price of blast furnace slag is relatively high in actual application and it is not suitable for large-scale use. Therefore, the present invention uses fly ash and blast furnace slag simultaneously, and the proportion of fly ash is higher.

[0054] As Figure 1 shown, a mix proportion design method for alkali-activated geopolymer concrete includes:

[0055] Step 1: Determine the optimum moisture content and maximum dry density of the soil according to the liquid-plastic limit test and compaction test of the soil. Specifically, initially estimate the optimum moisture content of the soil from the liquid-plastic limit of the soil, select the initially estimated optimum moisture content and two groups above and below it for the compaction test of the soil, and determine the optimum moisture content of the soil from the compaction curve. The basic properties of the soil are shown in Table 2.

[0056] Table 2 Basic properties of the soil

[0057]

[0058] Step 2: Initially select the initial mix ratio of each component of the geopolymer (soil, solid waste content, alkali activator content, water) according to the engineering requirements. Specifically, the solid waste content is taken as 8%, 10%, 12%, 14%; the alkali activator content is replaced by the percentage of the content of Na2O in the solidifying agent by mass for convenient calculation, and its range is taken as 6%, 8%, 10%, 12%; the solid waste ratio refers to the ratio of fly ash to blast furnace slag, which is taken as 9:1, 8:2, 7:3, 6:4.

[0059] Step 3: Establish the first orthogonal test table (Table 3) and calculate the dosage of each component. Specifically, take the solid waste content, Na2O content, and solid waste ratio as three factors, take the four levels described in Step 2, make an orthogonal test table of three factors and four levels, and design a solid strength solidifying agent (the solid strength solidifying agent is a composition of cement and gypsum with a weight ratio of 1:1) and cement with dosages of 10% and 12% as the control group (G17 - G20), with a total of 20 groups of test numbers. For each group, make 6 parallel test blocks and take the average value.

[0060] Table 3 The first orthogonal test table

[0061]

[0062]

[0063] Step 4: Prepare the initial geopolymer solidified soil. Specifically, first weigh a certain amount of soil, alkali activator, solid waste (fly ash and blast furnace slag), and water respectively; secondly, mix and stir the solid waste and alkali activator for 10 minutes to obtain dry material A; then first place the weighed engineering soil in a cement mortar mixer and let it stand for 1 minute, and then place dry material A above it; finally, turn on the mixer, slowly add water while stirring, fully mix and stir for ten minutes to obtain geopolymer solidified soil B, and pour B into a tray and wait for it to cool to room temperature for standby.

[0064] Step 5: Molding and curing the initial geopolymer solidified soil. Specifically, put B cooled to room temperature into a sealed bag, remove the air in the bag, and carry out material sealing to make it initially hydrate. After 24 hours of material sealing, place the geopolymer solidified soil into a test mold of 50mm×50mm, and use a moldless compression tester to mold and compact it. Keep the pressure for about 10s after the compaction is completed and then take out the test block. After the taken-out test block stands still for 2 hours, demold it, and place the test block in a curing box with a humidity of 95 and a temperature of 20±5°C for 7 days.

[0065] Step 6: Conduct an unconfined compressive strength test on the test block for 7 days. Specifically, dry the surface of the cured test block, place it in a road strength tester, set the loading rate of the testing machine to 1mm / min, and conduct an unconfined compressive strength test. The test results are shown in Table 4. Conduct an intuitive analysis and range analysis on the 7-day unconfined test results, as shown in Table 5, to obtain the influence of different factors and different levels on the strength of the geopolymer solidified soil, such as Figure 2 、 Figure 3 and Figure 4 shown. Scientifically analyze the relationship between various factors, and select an appropriate ratio range for the early strength. Optimal range consideration criteria: The compressive strength is greater than 1.2Kpa to ensure the early strength of such soil mass. It is found during the test that the soil mass with a strength lower than this will crack during the curing process.

[0066] Table 4 Unconfined Compressive Strength Table for 7 Days

[0067]

[0068] Table 5 Range Analysis Table

[0069]

[0070]

[0071] In Table 5, the K value refers to the sum of the test data corresponding to a certain factor and a certain level, and the Kavg value refers to the corresponding average value.

[0072] Step 7: Establish the second orthogonal test table (Table 6), and the range is determined by Step 6;

[0073] Table 6 Second Orthogonal Test Table

[0074]

[0075] Step 8: Prepare the later geopolymer solidified soil. The preparation process and curing are the same as those in Steps 4 and 5, and the curing time is 28 days;

[0076] Step 9: Conduct an unconfined compressive strength test and a splitting strength test on the geopolymer solidified soil cured for 28 days. The compressive strength test is the same as in Step 6, and the splitting strength also uses a road strength tester. The test results are shown in Tables 7 and 8.

[0077] Table 7 Unconfined Compressive Strength Table for 28 Days

[0078]

[0079] Table 8 Splitting Strength Test Table for 28 Days

[0080]

[0081]

[0082] Step 10: Determine the final mix ratio of the geopolymer solidified soil according to the results of the unconfined and splitting tests. Specifically, select the two optimal groups from the 28-day unconfined compressive strength test table and the 28-day splitting strength test table: Group 5 and Group 6, which meet the 7-day early strength, as well as the 28-day later compressive and tensile strengths.

[0083] For Control Group 12 and Control Group 13, the material used is cement. First, in terms of strength, its early strength is relatively low; second, in terms of the environment, the production of cement materials will release a large amount of CO2, which is harmful to the environment, while solid waste materials contribute to resource utilization; finally, in terms of price, the price of cement is much higher than that of solid waste materials. Considering the above factors, Experimental Groups 5 and 6 are selected.

[0084] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and reference can be made to the description of the method part for the relevant parts.

[0085] The above has introduced in detail a kind of geopolymer solidified engineering soil and its mix ratio design method provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A mix proportion design method for geopolymer-solidified engineering muck, characterized in that The method includes the following steps: Step 1: Determine the optimum moisture content and the maximum dry density of the soil mass according to the liquid-plastic limit test and compaction test of the soil mass. Step 2: Initially select the components of the geopolymer according to the engineering requirements, including the initial mix ratio of the soil mass, solid waste content, alkali activator content, and water; the range of the initially selected mix ratio of the components of the geopolymer is as follows: based on the total weight of the soil mass and the curing agent being 100%, the solid waste content is 8% - 14%, the alkali activator content is calculated based on the Na2O content accounting for 6% - 12% of the mass of the curing agent, and the solid waste ratio is the mass ratio of fly ash to blast furnace slag being 6:4 to 9:

1. The curing agent refers to the solid waste and the alkali activator, and the solid waste refers to fly ash and slag. Step 3: Establish the first orthogonal test table, with the solid waste content, alkali activator content, and solid waste ratio as three factors, and set multiple levels for each factor. Step 4: Prepare specimens according to the first orthogonal test table, prepare geopolymer-solidified engineering soil, and conduct unconfined compressive strength tests after curing for 7 days. Step 5: Conduct range analysis on the test results, determine the influence degree of each factor on the strength, and select the mix ratio range with appropriate early strength. Step 6: Establish the second orthogonal test table, and further optimize the mix ratio design based on the mix ratio range determined in Step 5. Step 7: Prepare specimens according to the second orthogonal test table, prepare geopolymer-solidified engineering soil, and conduct unconfined compressive strength tests and splitting strength tests after curing for 28 days. Step 8: Determine the final mix ratio of the geopolymer-solidified engineering soil according to the test results of the 28-day unconfined compressive strength and splitting strength tests.

2. The mix proportion design method according to claim 1, characterized in that In Step 1, initially estimate the optimum moisture content of the soil mass from the liquid-plastic limit of the soil, select two groups above and below the initially estimated optimum moisture content for the compaction test of the soil mass, and determine the optimum moisture content of the soil mass from the compaction curve. Later, prepare the solidified soil at a unified moisture content to reduce the test volume.

3. The mix ratio design method according to claim 1, characterized in that In Step 2, the solid waste content takes 8%, 10%, 12%, 14%; the alkali activator content is replaced by the percentage of the Na2O content in the mass of the curing agent for convenient calculation, and its range takes 6%, 8%, 10%, 12%; the solid waste ratio refers to the ratio of fly ash to blast furnace slag taking: 9:1, 8:2, 7:3, 6:

4.

4. The mix ratio design method according to claim 1, characterized in that The first orthogonal test table is a three-factor and four-level total of 16 groups of tests; the second orthogonal test table is a three-factor and three-level total of 9 groups of tests, and 6 groups of parallel tests are designed for each group of tests, and 6 groups are prepared simultaneously to reduce the test volume. Design commercially available powder curing agents and cement as the control group. Regularly check the curing situation, remake the test blocks with efflorescence and the cracked test blocks to reduce the errors caused by test operations. Conduct range analysis of the data of the first orthogonal test table by SPSSAU, obtain the mean value line chart of the same factor and different levels, preferably select 3 groups of optimization ranges, and establish the second orthogonal test table again. The preferably selected 3 groups of ranges meet the requirements of the 7-day early strength, conduct 28-day unconfined and splitting strength tests on them, and finally preferably select the optimal mix ratio that meets the early strength, as well as the later compressive and tensile strengths.

5. The mix proportion design method according to claim 1, characterized in that, The specific steps for preparing geopolymer-solidified engineering soil residues in Step 4 include: (1) Weigh a certain amount of soil, alkali activator, solid waste (fly ash and blast furnace slag), and water respectively; (2) Mix the solid waste and the alkali activator and stir to obtain a dry material; (3) Place the engineering soil residues in a mixer, add the dry material and stir, while slowly adding water, and mix and stir until uniform; (4) Put the mixture into a sealed bag to remove air and let it sit for 24 hours; (5) Place the well-settled solidified soil in a test mold, compact it into shape, and perform curing after demolding.

6. The mix proportion design method according to claim 1, characterized in that The method for performing the range analysis in Step 5 is to calculate the average strength values of different levels of each factor and draw the effect curve of the influence of each factor on the strength.

7. A geopolymer-solidified engineering muck, characterized in that It is prepared by the following method: (1) Prepare raw materials, including engineering soil residues, blast furnace slag, fly ash, and sodium metasilicate; (2) Mix the blast furnace slag and fly ash in proportion and stir them together with sodium metasilicate to obtain a dry material; (3) Place the engineering soil residues in a mixer, add the dry material and stir, while slowly adding water, and mix and stir until uniform; (4) Put the mixture into a sealed bag to remove air and let it sit for 24 hours; (5) Compact and shape the well-settled solidified soil, and obtain geopolymer-solidified engineering soil residues after curing.

8. The geopolymer-solidified engineering muck according to claim 7, wherein This method uses blast furnace slag and fly ash as cementitious materials and sodium metasilicate as an alkali activator to solidify engineering soil residues. The chemical components of the blast furnace slag in the cementitious materials are: SiO2, 34.17; CaO, 33.29; Al2O3, 17.86; MgO, 10.62; Fe2O3, 0.31; Na2O, 0.44; SO3, 1.

88. The chemical components of the fly ash are: SiO2, 49.81; CaO, 2.96; Al2O3, 38.48; MgO, 0.82; Fe2O3, 3.95; Na2O, 0.39; SO3, 0.65; The modulus of the alkali activator is 1.

0.

9. The geopolymer-solidified engineering muck according to claim 7, wherein The sodium metasilicate is in powder form and its modulus is 1.

0. Calculated based on the total weight of the soil body and the solidifying agent being 100%, the solid waste content is 12%, and the ratio of fly ash to blast furnace slag is 0.6 - 0.

7. The dosage of the sodium metasilicate is calculated based on the Na2O content accounting for 10% - 12% of the total mass of the solidifying agent.

10. The geopolymer-solidified engineering muck according to claim 7, wherein, The curing conditions in Step (5) are: humidity 95%, temperature 20 ± 5°C.

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