Geopolymer modified dispersive soil, method of making and use thereof

Abstract

This invention provides a geopolymer-modified dispersible soil, its preparation method, and its application, belonging to the field of soil improvement technology. This invention utilizes a geopolymer gel system of aluminosilicates generated from slag and silica powder under alkali activation. This system covers, binds, and fills dispersible soil particles, thereby reducing the dispersibility of the soil, improving its impermeability and mechanical properties, and realizing the resource utilization of industrial solid waste, showing promising engineering application prospects. Compared with traditional cement or lime-based methods for improving dispersible soil, this invention achieves effective modification of dispersible soil at lower dosages, reducing emissions of pollutants such as carbon dioxide, sulfur oxides, and nitrogen oxides during production, demonstrating good environmental friendliness and resource utilization value.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement technology, specifically relating to a geopolymer-modified dispersible soil, its preparation method, and its application. Background Technology

[0002] Dispersible soil refers to water-sensitive soil whose soil particles are suspended and flocculated in water, making them easily eroded and carried away by rainwater or seepage. Dispersible soil has low erosion resistance, and its degradation process is rapid and insidious, easily causing disasters such as piping in dams, erosion in channels, and slope instability. Therefore, it needs to be modified before use in water conservancy projects. Commonly used methods for modifying dispersible soil include physical and chemical treatment methods. Physical treatment methods mainly include using geomembranes to separate the dispersible soil from water with low salinity and setting up appropriately graded sand filters to trap fine soil particles. Chemical treatment methods mainly involve adding materials such as lime, cement, aluminum sulfate, calcium chloride, and aluminum chloride to transform dispersible or transitional soil into non-dispersible soil.

[0003] However, current decentralized soil chemical treatment methods typically suffer from problems such as high carbon emissions, high costs, and environmental pollution. Summary of the Invention

[0004] The purpose of this invention is to provide a geopolymer-modified dispersible soil, its preparation method, and its application. This invention uses slag and silica powder to form a geopolymer cementitious material under the action of an alkaline activator to modify the dispersible soil. The low content of slag and silica powder in this invention can reduce the emission of pollutants such as carbon dioxide, sulfur oxides, and nitrogen oxides during the production process, and has good environmental friendliness and resource utilization value.

[0005] To achieve the objectives of this invention, the following technical solutions are provided: A geopolymer-modified dispersible soil includes dispersible soil and a geopolymer gel filling between the dispersible soil particles and on the surface of the dispersible soil. The geopolymer gel is formed by activating composite powder with an alkaline activator; the composite powder is slag and silica powder. The total mass of the composite powder and alkali activator is 0.5 to 9.0% of the dry mass of the dispersible soil.

[0006] Preferably, the slag is S95 grade granulated blast furnace slag; The slag comprises, by mass percentage: 32.0-33.5% SiO2, 14.7-15.8% Al2O3, 36.1-37.9% CaO, 8.0-9.2% MgO, 0.4-0.7% Fe2O3 and 0.1-0.3% TiO2.

[0007] Preferably, the SiO2 content in the silicon powder is ≥90wt%.

[0008] Preferably, the mass ratio of the slag to the silicon powder is 1:3 to 3:1.

[0009] Preferably, the alkaline activator is sodium hydroxide and water glass; the modulus of the water glass is 1.0 to 2.2.

[0010] Preferably, the mass ratio of sodium hydroxide to water glass is 1:1 to 3.

[0011] Preferably, the dispersible soil comprises one or more of quartz, illite, kaolinite, and montmorillonite.

[0012] This invention also provides a method for preparing the geopolymer-modified dispersible soil described in the above technical solution, comprising the following steps: Slag and silicon powder are mixed to obtain composite powder; Sodium hydroxide and water glass are mixed to obtain an alkaline activator; The composite powder and the alkali activator are mixed and reacted to obtain a geopolymer gel system; The geopolymer gel system, dispersible soil, and water are mixed and cured to obtain the geopolymer-modified dispersible soil.

[0013] Preferably, the curing temperature is 25~40℃, the relative humidity is 30~65%, and the time is 7~28 days.

[0014] The present invention also provides the application of the geopolymer-modified dispersible soil described in the above technical solution or the geopolymer-modified dispersible soil prepared by the preparation method described in the above technical solution in the filling of dam bodies, channel lining or foundation treatment of water-retaining structures in water conservancy projects.

[0015] This invention provides a geopolymer-modified dispersible soil, comprising dispersible soil and a geopolymer gel filling the spaces between the dispersible soil particles and on the surface of the dispersible soil. The geopolymer gel is formed by activating a composite powder with an alkali activator. The composite powder is slag and silica fume. The total mass of the composite powder and the alkali activator is 0.5-9.0% of the dry mass of the dispersible soil. This invention uses geopolymer cementitious materials formed by slag and silica fume under the action of an alkali activator to modify dispersible soil. This cementitious material can fill soil pores and enhance the bonding between soil particles through covering, cementing, and filling effects, thereby improving soil density and structural stability and reducing the dispersibility of the dispersible soil. Furthermore, both slag and silica fume are industrial solid waste resource utilization materials. Compared with traditional cement or lime-based amendments, the dosage of the modified system in this invention is only 0.5-5%, which can reduce the emission of pollutants such as carbon dioxide, sulfur oxides, and nitrogen oxides during production, exhibiting good environmental friendliness and resource utilization value.

[0016] The results of the embodiments of this invention show that: 1) The unconfined compressive strength of the dispersible soil modified by the method of this invention is improved, indicating that the slag-silica powder alkali-activated geopolymer system can enhance the cementation between soil particles and improve the mechanical properties of the soil. 2) The results of pinhole test, fragment test and mud ball test show that under low dosage conditions, the slag-silica powder alkali-activated composite system can transform the dispersible soil from dispersible or transitional to non-dispersible, indicating that the modified system can effectively reduce the dispersibility of the soil and improve the stability of the soil. 3) The results of the permeability test show that the permeability coefficient of the dispersible soil modified by the slag-silica powder alkali-activated geopolymer system is reduced, indicating that the modified system can fill the pores of the soil and form a cemented structure, thereby improving the impermeability of the soil. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a gradation curve diagram of the raw material dispersible soil; Figure 2 The compaction curve of the raw material dispersible soil; Figure 3 This is a microstructure diagram of the geopolymer-modified dispersible soil obtained in Example 1 of the present invention; Figure 4 This is a schematic diagram of the mechanism of geopolymer-modified dispersible soil modification obtained in Example 1 of the present invention; Figure 5 The results show a comparison of the permeability coefficients of the unmodified dispersible soil and the slag-modified dispersible soil obtained in Example 3. Figure 6 The results show a comparison of the permeability coefficients of the unmodified dispersible soil and the silica fume-modified dispersible soil obtained in Example 3. Figure 7 The results show a comparison of the permeability coefficients of unmodified dispersible soil and geopolymer-modified dispersible soil obtained in Example 3. Detailed Implementation

[0019] The present invention provides a geopolymer-modified dispersible soil, comprising dispersible soil and a geopolymer gel filling between the dispersible soil particles and on the surface of the dispersible soil. The geopolymer gel is formed by activating composite powder with an alkaline activator; the composite powder is slag and silica powder. The total mass of the composite powder and alkali activator is 0.5 to 9.0% of the dry mass of the dispersible soil.

[0020] In this invention, unless otherwise specified, all raw materials are commercially available products well known to those skilled in the art.

[0021] In this invention, the dispersible soil comprises one or more of quartz, illite, kaolinite, and montmorillonite; the moisture content of the dispersible soil is 10-17%, and in specific embodiments it can be 11.5%, 13.6%, 14.2%, or 16.5%, with a maximum dry density of 1.2-1.9 g / cm³. 3 In a specific embodiment, it can be 1.33 g / cm³. 3 1.54 g / cm 3 Or 1.71 g / cm 3 The particle size distribution of the dispersible soil is 0.002 mm to 0.398 mm.

[0022] In this invention, the slag is S95 grade granulated blast furnace slag; by mass percentage, the slag composition includes: 32.0~33.5% SiO2, 14.7~15.8% Al2O3, 36.1~37.9% CaO, 8.0~9.2% MgO, 0.4~0.7% Fe2O3 and 0.1~0.3% TiO2; in a specific embodiment, it can be 32.90% SiO2, 15.36% Al2O3, 37.04% CaO, 8.52% MgO, 0.57% Fe2O3 and 0.24% TiO2; the particle size of the slag can be 25μm.

[0023] In this invention, the SiO2 content in the silicon powder is ≥90wt%, which can be 90~97wt%, and in a specific embodiment it can be 95.69wt%; the particle size of the silicon powder is 5μm.

[0024] In this invention, the mass ratio of slag to silicon powder is 1:3 to 3:1, and in specific embodiments it can be 1:1, 1:1.5, 1:1.7, 1:2.0, 1:2.3, 1:2.5, 1.5:1, 1.8:1, 2.1:1, 2.3:1, or 2.5:1. Both the slag and silicon powder of this invention belong to the category of industrial solid waste resource utilization materials. Compared with traditional cement or lime-based modifiers, it can reduce the emission of pollutants such as carbon dioxide, sulfur oxides, and nitrogen oxides during the production process, exhibiting good environmental friendliness and resource utilization value.

[0025] In this invention, the alkaline activator is sodium hydroxide and water glass; the NaOH is solid particles with a purity of 96%; the modulus of the water glass is 1.0~2.2, and in specific embodiments it can be 1.3, 1.6, 1.7, 1.9 or 2.0; the mass ratio of sodium hydroxide to water glass is 1:1~3, and in specific embodiments it can be 1:1.2, 1:1.5, 1:1.9, 1:2.3, 1:2.5 or 1:2.8. The hydration products CASH and NASH generated from slag and silica powder under the action of the alkaline activator of water glass in this invention improve the bonding force and stability between dispersed soil particles, leading to increased soil strength and decreased permeability. In this invention, the total mass of the composite powder and the alkali activator is 0.5 to 9.0% of the dry mass of the dispersible soil. In specific embodiments, it can be 1.5%, 2.0%, 2.5%, 3%, 3.7%, 4.5%, 5%, 7%, 7.5% or 9.0%.

[0026] This invention also provides a method for preparing the geopolymer-modified dispersible soil described in the above technical solution, comprising the following steps: Slag and silicon powder are mixed to obtain composite powder; Sodium hydroxide and water glass are mixed to obtain an alkaline activator; The composite powder and the alkali activator are mixed and reacted to obtain a geopolymer gel system; The dispersible soil, the geopolymer gel system, and water are mixed and cured to obtain the geopolymer-modified dispersible soil.

[0027] The present invention does not have any special limitation on the mixing method in the preparation method of geopolymer modified dispersible soil. Mixing uniformity can be achieved by using a mixing method well known to those skilled in the art.

[0028] The present invention mixes a dispersible soil, a geopolymer gel system and water, and the resulting mixture has a water content of 5-22%.

[0029] In this invention, the curing temperature is 25~40℃, the relative humidity is 30~65%, and the time is 7~28 days.

[0030] The present invention also provides the application of the geopolymer-modified dispersible soil described in the above technical solution or the geopolymer-modified dispersible soil prepared by the preparation method described in the above technical solution in the filling of dam bodies, channel lining or foundation treatment of water-retaining structures in water conservancy projects.

[0031] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, describes the geopolymer-modified dispersible soil, its preparation method, and its application, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0032] The parameters and sources of the dispersible soil, slag, and silica fume in the following embodiments of the present invention are as follows: Dispersed soil: Samples were taken from a reservoir project site at a depth of 1.0–2.0 m. The physical properties of the dispersed soil were determined according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019). Table 1 shows the basic physical property indicators of the dispersed soil. Figure 1 The gradation curve of the dispersive soil is shown. Based on the range of the coefficient of uniformity and the coefficient of curvature, the test soil sample can be identified as poorly graded soil. Figure 2 The compaction curve of the dispersible soil shows that the optimum moisture content is 14.2% and the maximum dry density is 1.71 g / cm³. 3 .

[0033] Table 1 Basic Physical Properties of Dispersible Soil

[0034] Slag: S95 grade granulated blast furnace slag; Silicon powder: Amorphous silicon micropowder with SiO2 as the main component, and SiO2 content greater than 95%; the chemical composition of slag and silicon powder is shown in Table 2.

[0035] Table 2 Chemical composition of slag and silica powder

[0036] Example 1 Modified dispersible soil was prepared according to the orthogonal experimental scheme for geopolymer-modified dispersible soil shown in Table 3. The specific steps are as follows: Dispersed soil was air-dried, crushed, and sieved through a 0.5 mm sieve to obtain dispersed soil to be treated. Granulated blast furnace slag was mixed with silica powder to obtain geopolymer composite powder. Sodium hydroxide and water glass solution were mixed (mass ratio 1:1) to obtain alkali activator. The geopolymer composite powder and alkali activator were mixed to obtain a geopolymer system. The geopolymer system was added to the dispersed soil to be treated, and water was added to a moisture content of 14.2%. The mixed soil was placed into a 39.1 mm × 80 mm mold and compacted in layers. After the sample preparation was completed, it was placed in a vacuum bag for sealed curing.

[0037] After curing, the specimens were placed in a KTL-LDF 50 soil static triaxial testing machine and subjected to unconfined compressive strength test in accordance with the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019). Specifically, axial pressure was applied under a confining pressure of 0 kPa until the specimen failed, and the maximum axial stress at the time of specimen failure was recorded as the unconfined compressive strength.

[0038] Table 3 shows the orthogonal test scheme for geopolymer-modified dispersible soil. A total of 25 sets of tests were carried out, and each set of tests was repeated.

[0039] Table 3. Orthogonal test scheme for geopolymer-modified dispersible soil

[0040] Table 4 shows the orthogonal test results of the unconfined compressive strength of geopolymer-modified dispersible soil. Unconfined compressive strength tests were conducted on each combination of samples, and the results are shown in Table 4. Among the tested combinations, the highest unconfined compressive strength (307.11 kPa) was achieved when the water glass modulus was 1.3, the slag to silica fume mass ratio was 3:7, and the slag-silica fume content was 9%. Considering both strength level and material applicability, the preferred parameters for this invention are determined to be: a water glass modulus of 1.9, a slag to silica fume mass ratio of 1:1, and a slag-silica fume content of 5%. This combination ensures high strength while exhibiting better economy and stability.

[0041] Table 4. Results of orthogonal tests on geopolymer-modified dispersible soil

[0042] Figure 3 This is a microstructure diagram of the geopolymer-modified dispersible soil obtained in Example 1 of the present invention, wherein the water glass modulus is 1.3, the slag to silica fume mass ratio is 3:7, and the admixture content is 9%; Figure 3The results show that the modified dispersible soil has a relatively uniform pore distribution with varying pore sizes, exhibiting a relatively loose structure. The dispersible soil particles are composed of minerals such as quartz, illite, kaolinite, and montmorillonite, and exhibit weak inter-particle connections. The hydration products CASH and NASH, generated from slag and silica fume under the action of an alkaline activator of water glass, improve the cohesion and stability between the dispersible soil particles, leading to increased soil strength and decreased permeability.

[0043] Figure 4 This is a schematic diagram of the mechanism of geopolymer-modified dispersible soil modification obtained in Example 1 of the present invention; Figure 4 It is known that slag and silica fume generate CASH and NASH gels under the action of alkaline activators, which then connect soil particles through covering, cementing and filling effects, thereby improving the strength of dispersed soil.

[0044] Example 2 Geopolymer-modified dispersible soil was prepared according to the method described in Example 1. The difference was that samples were prepared according to Tables 5-7 for slag-doped single-component system, silica fume-doped single-component system, and slag-silica fume alkali-activated composite system. The properties of slag, silica fume, and slag-silica fume geopolymer-modified dispersible soil were identified by pinhole test, fragment test, and mud ball test.

[0045] 1) The specific steps of the pinhole test are as follows: Prepare a cylindrical specimen measuring 25.4 mm × 38.1 mm, create a 1.0 mm pinhole in the center of the specimen, and conduct seepage tests under different water head conditions. During the test, the soil dispersibility is determined by observing changes in the outflow rate, outflow color, and pinhole diameter. Four water head conditions (50 mm, 180 mm, 380 mm, and 1020 mm) are set during the test. After the water flows through the pinhole, the soil dispersibility is comprehensively judged based on the turbidity of the outflow and the expansion of the pinhole.

[0046] 2) The specific steps of the fragment test are as follows: Cut the sample into cubic soil blocks with a side length of approximately 10 mm, place them in a beaker containing clean water, and observe the disintegration of the soil blocks in the water and the turbidity of the water. During the test, the dispersibility of the soil is determined based on the disintegration rate of the soil blocks and the degree of turbidity of the water. Generally, dispersible soils and transitional soils will form obvious turbid suspensions in water, and the water will exhibit a "cloudy" turbidity phenomenon; as the dispersibility decreases, the degree of turbidity of the water gradually weakens; while non-dispersible soils remain basically clear in water, with only a small amount of particle sedimentation.

[0047] 3) The specific steps of the mud ball test are as follows: Mix the sample with water until homogeneous, and shape it into mud balls with a diameter of approximately 15 mm. Place the mud balls in a beaker containing clear water for observation. During the test, the dispersibility of the soil is determined by observing the disintegration of the mud balls in water and the degree of turbidity of the water. Generally, dispersible soils will rapidly disintegrate in water and form a noticeably turbid suspension; transitional soils disintegrate more slowly, and the water becomes slightly turbid; non-dispersible soils remain largely intact, the water remains clear, and only a small number of particles settle.

[0048] Table 5. Comprehensive Judgment Results of Slag-Modified Dispersible Soil

[0049] Table 6. Comprehensive Judgment Results of Silica Powder Modified Dispersible Soil

[0050] Table 7. Comprehensive Judgment Results of Geopolymer-Modified Dispersible Soils

[0051] As shown in Tables 5-7, the slag-based single-component system can transform the soil into a non-dispersible state when the dosage reaches 10%; the silica fume-based single-component system can transform the soil into a non-dispersible state when the dosage reaches 16%; while the slag-silica fume alkali-activated composite system of the present invention can transform the soil into a non-dispersible state when the dosage reaches 2.0%, and the limit dosage is significantly reduced.

[0052] Example 3 Geopolymer-modified dispersible soil was prepared according to the method described in Example 1. The difference was that unmodified dispersible soil, slag-modified dispersible soil, silica fume-modified dispersible soil, and slag-silica fume geopolymer-modified dispersible soil samples were prepared according to Table 8. The obtained samples were subjected to constant and variable head permeability tests to test their permeability coefficient k.

[0053] The constant-head permeability test was conducted according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019). The test was carried out at 20℃, and the permeability coefficient of the sample was determined using a constant-head permeability apparatus. After sample preparation, the sample was placed in a TST-55 dual permeameter, and the permeation test was conducted under stable head conditions. The amount of water passing through the sample over a certain period of time was recorded. The permeability coefficient of the sample was calculated according to the standard test method. The formula for calculating the permeability coefficient is as follows: In the formula: k T Permeability coefficient (cm / s); Q is the permeation volume (cm³) at time t. 3 L is the height of the sample at the center of the indentation (cm); A is the cross-sectional area of ​​the sample (cm²). 2); t is time (s); H1 and H2 are the water level difference in the pipe (cm).

[0054] Table 8. Test schemes for permeability, unconfined compressive strength and disintegration of geopolymer-modified dispersible soils.

[0055] The results in Table 8 show that the permeability coefficients of all soil samples decreased with increasing dry density. Under the same dry density conditions, the permeability coefficients of modified dispersible soils were lower than those of unmodified dispersible soils, and further decreased with increasing admixture dosage.

[0056] Figure 5 The results show a comparison of the permeability coefficients of the unmodified dispersible soil and the slag-modified dispersible soil obtained in Example 3. Figure 6 The results show a comparison of the permeability coefficients of the unmodified dispersible soil and the silica fume-modified dispersible soil obtained in Example 3. Figure 7 This is a comparison of the permeability coefficients of the unmodified dispersible soil and the geopolymer-modified dispersible soil obtained in Example 3. Figures 5-7 The results show that when the dry density is 1.50 g / cm³ 3 At that time, the permeability coefficient of unmodified dispersible soil was approximately 16.8 × 10⁻⁶. -5 cm / s; the permeability coefficient of slag (10%) modified soil is 8.64×10 cm / s. -5 cm / s; the permeability coefficient of silica fume (16%) modified soil is approximately 5.84 × 10⁻⁶ cm / s. -5 cm / s; the permeability coefficient of the geopolymer (2%) modified soil is 2.9 × 10 cm / s. -5 cm / s. When the dry density is 1.70 g / cm³. 3 At that time, the permeability coefficient of unmodified dispersed soil was approximately 8.8 × 10⁻⁶. -5 cm / s; the permeability coefficient of slag (10%) modified soil is 1.00×10 cm / s. -5 cm / s; the permeability coefficient of silica fume (15%) modified soil is approximately 2.11 × 10⁻⁶ cm / s. -5 cm / s; the permeability coefficient of the geopolymer (2%) modified soil is 0.94×10 cm / s. -5 cm / s. Compared to unmodified dispersible soil, at a dry density of 1.70 g / cm³, 3 At this point, the permeability coefficient of the geopolymer-modified soil decreased by approximately 89%, and even at a relatively low dosage (2%), it achieved a permeability coefficient lower than that of slag-modified or silica-modified soils. This demonstrates that the slag-silica alkali-activated geopolymer system can significantly reduce the permeability coefficient of dispersible soils and improve their impermeability.

[0057] In summary, the geopolymer-modified dispersible soil provided by this invention can transform dispersible soil from a dispersed state to a transitional or non-dispersible state when the geopolymer content is 1.0~2.0%. By constructing a synergistic alkali-activated system of slag and silica fume, a continuous and stable aluminosilicate gel network structure can be formed under low dosage conditions. This network structure covers, cements, and fills the dispersible soil particles, thereby significantly reducing the dispersibility of the soil and improving its impermeability, mechanical properties, and durability. Compared with single-admixture modification methods using slag or silica fume, the composite system constructed in this invention has a lower limit dosage and a more significant modification effect, showing good engineering application prospects. It can be used for the treatment of dispersible soil in water conservancy projects such as dam bodies, canal linings, and water-retaining structures.

[0058] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A geopolymer-modified dispersible soil, characterized in that, Includes dispersed soil and geopolymer gel filling the spaces between the dispersed soil particles and on the surface of the dispersed soil; The geopolymer gel is formed by activating composite powder with an alkaline activator; the composite powder is slag and silica powder. The total mass of the composite powder and alkali activator is 0.5 to 9.0% of the dry mass of the dispersible soil.

2. The geopolymer-modified dispersible soil according to claim 1, characterized in that, The slag is S95 grade granulated blast furnace slag; The slag comprises, by mass percentage: 32.0-33.5% SiO2, 14.7-15.8% Al2O3, 36.1-37.9% CaO, 8.0-9.2% MgO, 0.4-0.7% Fe2O3 and 0.1-0.3% TiO2.

3. The geopolymer-modified dispersible soil according to claim 1, characterized in that, The silicon powder contains ≥90wt% SiO2.

4. The geopolymer-modified dispersible soil according to claim 2 or 3, characterized in that, The mass ratio of slag to silicon powder is 1:3 to 3:

1.

5. The geopolymer-modified dispersible soil according to claim 1, characterized in that, The alkaline activator is sodium hydroxide and water glass; the modulus of the water glass is 1.0~2.

2.

6. The geopolymer-modified dispersible soil according to claim 5, characterized in that, The mass ratio of sodium hydroxide to water glass is 1:1~3.

7. The geopolymer-modified dispersible soil according to claim 1, characterized in that, The dispersed soil includes one or more of quartz, illite, kaolinite, and montmorillonite.

8. The method for preparing geopolymer-modified dispersible soil according to any one of claims 1 to 7, characterized in that, Includes the following steps: Slag and silicon powder are mixed to obtain composite powder; Sodium hydroxide and water glass are mixed to obtain an alkaline activator; The composite powder and the alkali activator are mixed and reacted to obtain a geopolymer gel system; The geopolymer gel system, dispersible soil, and water are mixed and cured to obtain the geopolymer-modified dispersible soil.

9. The preparation method according to claim 8, characterized in that, The curing temperature is 25~40℃, the relative humidity is 30~65%, and the time is 7~28 days.

10. The application of the geopolymer-modified dispersible soil according to any one of claims 1 to 7 or the geopolymer-modified dispersible soil prepared by the preparation method according to claim 8 or 9 in the filling of dam bodies, lining of channels or foundation treatment of water-retaining structures in water conservancy projects.

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