Soil anti-seepage improvement method based on gelatinized tapioca flour

Abstract

The invention discloses a soil anti-seepage improvement method based on gelatinized tapioca flour, and belongs to the technical field of geological engineering and geotechnical engineering.The gelatinized tapioca flour is applied into soil to form an improved soil body with a framework filling-particle adhesion composite structure, and the excellent anti-seepage performance is still achieved under low compactness; and on the premise of environmental friendliness, the dependence of an anti-seepage project on the compactness is obviously weakened. According to the soil anti-seepage improvement method, the saturated permeability coefficient is remarkably reduced, and the engineering anti-seepage requirement can still be met especially under the condition of low compactness, so that the dependence on compaction equipment and construction quality is reduced, the construction efficiency is improved, and the cost is reduced. The natural organic material tapioca flour is adopted and is environmentally friendly and high in stability, and the improved soil doped with the gelatinized tapioca flour has a more stable soil-water characteristic curve and is high in adaptability to dry and wet changes of the soil.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anti-freeze-thaw materials, and particularly relates to a soil anti-seepage improvement method based on gelatinized cassava powder. BACKGROUND

[0002] In existing engineering, the anti-seepage performance of loess is often improved by increasing the compaction degree, and the methods of dynamic compaction and layer-by-layer filling and compaction are representative. However, the dynamic compaction method has problems such as high construction energy consumption, great influence of weather, and noise influence. The layer-by-layer filling and compaction method has the defect of long construction period of high pressure, and the commonly used methods are difficult to achieve uniform compaction in the construction restricted area (such as the connection part between the structure and the compaction area). In general engineering practice, such as roadbed filling, the compaction degree is generally required to be 90% or even higher, and in water conservancy engineering, the compaction degree of the anti-seepage core wall is required to be 98%. Reducing the compaction degree requirement can reduce the rolling operation, thereby directly reducing the mechanical station cost, and avoiding the risk of soil structure damage caused by excessive compaction or uneven compaction.

[0003] In view of the above problems, it is particularly important to seek an improvement method for soil anti-seepage. The prevailing improvement methods include adding cement and fly ash into soil. Although the above-mentioned methods can improve the performance, they have poor environmental friendliness, and the anti-seepage performance of soil still depends on the compaction degree. SUMMARY

[0004] The present application provides a soil anti-seepage improvement method based on gelatinized cassava powder, which effectively solves the technical problems that the anti-seepage performance of existing soil depends on high compaction degree and that the anti-seepage performance of soil and environmental protection cannot be considered when the existing improvement method is used. The present application improves the soil by using gelatinized cassava powder, adds the gelatinized cassava powder into the soil, forms an improved soil body with a composite structure of skeleton filling-micro-particle adhesion, realizes excellent anti-seepage performance under low compaction degree, significantly weakens the dependence of anti-seepage engineering on compaction degree under the premise of environmental friendliness.

[0005] The first object of the present application is to provide a soil anti-seepage improvement method based on gelatinized cassava powder, which comprises the following steps: Preparation of gelatinized cassava powder.

[0006] Add the gelatinized cassava powder into the soil, mix with water, fill the soil pores with gelatinized cassava powder particles, and produce adhesion effect on soil particles to obtain anti-seepage improved soil.

[0007] As a preferred embodiment, the mass ratio of the soil to the cassava powder is 50:2-3, based on the absolute dry soil and the absolute dry cassava powder.

[0008] As a preferred embodiment, the mass ratio of the soil to the cassava powder is 20:1.

[0009] As a preferred embodiment, the moisture content of the soil after compaction is 18% to 20%.

[0010] As a preferred embodiment, the compaction degree of the soil after compaction is 80% to 85%.

[0011] As a preferred embodiment, the permeability coefficient of the soil after compaction is 1.35*10 -6 cm / s to 1.28*10 -6 cm / s.

[0012] As a preferred embodiment, the preparation method of the gelatinized cassava powder comprises the following steps: mixing cassava powder with water to obtain cassava paste, and then adding boiling water to gelatinize the cassava powder to obtain gelatinized cassava powder.

[0013] As a preferred embodiment, the mass ratio of the cassava powder to water is 1:1 to 2, based on the absolute dry cassava powder.

[0014] As a preferred embodiment, the mass ratio of the cassava powder to boiling water is 1:2 to 4, based on the absolute dry cassava powder.

[0015] Compared with the prior art, the beneficial effects of the present application are as follows: The present application provides a soil anti-seepage improvement method based on gelatinized cassava powder. The gelatinized cassava powder is mixed into the soil, and the gelatinized cassava powder particles exist as skeleton particles in the soil body, promoting the densification of the microstructure and reducing the permeability coefficient through the large pore plugging effect. The tiny soil particles are adhered around the large particles of gelatinized cassava powder, improving the stability of the internal pore of the sample and limiting the flow of water, thereby forming an improved soil body with a "skeleton filling-micro-particle adhesion" composite structure, achieving excellent anti-seepage performance under low compaction degree, significantly weakening the dependence of anti-seepage engineering on compaction degree under the premise of environmental friendliness. The present application uses the incorporation of gelatinized cassava powder to fill a large number of dominant water-permeable pores in the soil, which greatly reduces the proportion of the dominant water-permeable pores, thereby greatly reducing the saturated permeability coefficient of the sample. The soil anti-seepage improvement method provided by the present application significantly reduces the saturated permeability coefficient, and can still meet the engineering anti-seepage demand under low compaction degree, thereby reducing the dependence on compaction equipment and construction quality, improving the construction efficiency and reducing the cost. The present application uses natural organic material cassava powder, which is environmentally friendly and has high stability. The improved soil mixed with gelatinized cassava powder has a more stable soil-water characteristic curve and strong adaptability to dry and wet changes of the soil. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the permeability comparison chart of the improved soil and the original soil of the present application under different compaction degrees.

[0017] Figure 2Soil permeability coefficient of the raw soil of the present application comparative example 3 and the cassava powder improved soil of the present application comparative example 4 with the change of compaction degree.

[0018] Figure 3 The figure of the permeability coefficient of the soil of the present application with the change of the cassava powder addition amount.

[0019] Figure 4 The pore distribution comparison figure of the improved soil of the present application example 1 and the raw soil of the comparative example 1.

[0020] Figure 5 The microstructure difference comparison figure of the improved soil of the present application example 1 and the raw soil of the comparative example 1.

[0021] Figure 6 The soil-water characteristic curve comparison figure of the improved soil of the present application example 1 and the raw soil of the comparative example 1. DETAILED DESCRIPTION

[0022] In order to make the person skilled in the art better understand the technical scheme of the present application can be implemented, the following specific examples of the present application are further described, but the examples are not as a limitation of the present application. The following test methods and detection methods, such as no special instructions, are the conventional method; the reagent and raw material, such as no special instructions, are commercially available.

[0023] The existing soil anti-seepage performance depends on high compaction degree, and the soil anti-seepage performance and environmental protection cannot be considered when using the existing improvement method. Based on the above technical problems, the present application provides a soil anti-seepage improvement method based on gelatinized cassava powder.

[0024] The technical scheme of the present application is described in detail below.

[0025] The present application provides a soil anti-seepage improvement method based on gelatinized cassava powder, comprising the following steps: S1, preparing gelatinized cassava powder: mixing cassava powder and water uniformly to obtain cassava paste, and then adding boiling water to gelatinize the cassava powder to obtain gelatinized cassava powder.

[0026] S2, mixing the gelatinized cassava powder into the soil and mixing uniformly with water, so as to fill the soil pores with the gelatinized cassava powder particles and produce adhesion effect on the soil particles, to obtain an anti-seepage improved soil.

[0027] In the aforementioned technical solution, gelatinized cassava flour is incorporated into the soil. The gelatinized cassava flour particles act as skeletal particles within the soil, promoting microstructural compaction and reducing the permeability coefficient through a macropore-sealing effect. Small soil particles adhere to the larger gelatinized cassava flour particles, improving the stability of the pores within the sample and restricting water flow. This forms an improved soil with a "skeleton-filled-particle-adhesive" composite structure, achieving excellent seepage prevention performance even at low compaction levels. Under environmentally friendly conditions, this significantly reduces the dependence of seepage prevention projects on compaction levels. This invention uses gelatinized cassava flour to fill a large number of dominant permeable pores in the soil, significantly reducing the proportion of dominant permeable pores and thus greatly lowering the saturated permeability coefficient of the sample.

[0028] To effectively improve the soil's seepage prevention effect, this invention limits the mass ratio of soil to cassava flour to 50:2~3, based on absolutely dry soil and absolutely dry cassava flour. Loess-cassava flour improvement experiments of this invention show that with the increase of cassava flour content, the seepage prevention effect is significantly improved. When the mass ratio of soil to cassava flour is 20:1, the soil still has the best seepage prevention effect even under low compaction. With further increases in cassava flour content, the soil saturation coefficient fluctuates, and the stability of the seepage prevention effect decreases.

[0029] It should be noted that after compaction, the soil moisture content is 18% to 20%. The seepage prevention effect decreases both above and below this moisture content range.

[0030] To further improve the soil's seepage prevention effect, the compaction degree of the soil should be 80%~85% after compaction. When the compaction degree is below 80%, the permeability coefficient is mostly around 10. -6 The permeability coefficient is below the cm / s level; as the compaction degree increases, the seepage prevention performance is further enhanced, but the required compaction work increases significantly, reducing economic efficiency. It should be noted that, in this invention, after incorporating gelatinized cassava flour into the soil and compacting it, the soil permeability coefficient can be controlled to 1.35 × 10⁻⁶. -6 cm / s ~ 1.28 × 10 -6 The flow rate was cm / s, thus achieving a better seepage prevention improvement effect.

[0031] In this invention, the method for preparing the gelatinized cassava flour includes the following steps: mixing cassava flour with water to obtain cassava paste, then adding boiling water to gelatinize the cassava flour to obtain gelatinized cassava flour.

[0032] To improve the gelatinization effect of cassava flour, this invention limits the mass ratio of cassava flour to water to 1:1~2 based on oven-dried cassava flour. The cassava flour is first converted into a cassava paste to prevent agglomeration of the flour upon addition of boiling water, which would lead to uneven gelatinization and affect the subsequent soil seepage prevention and improvement effect. Adding water at a mass ratio less than the specified 1 or greater than 2 will both negatively impact the gelatinization effect.

[0033] In order to promote the sufficient gelatinization of cassava powder, the mass ratio of the cassava powder to boiling water is 1:2-4 based on the absolute dry cassava powder. When the mass ratio of boiling water is less than 2 defined herein, the cassava powder is not uniformly gelatinized, which affects the soil anti-seepage improvement effect; when the mass ratio of boiling water is greater than 4 defined herein, the gelatinization effect of the cassava powder will not be affected, but too much water will cause the gelatinized cassava powder to be too thin, and the filling effect on the soil pores will also be affected when the gelatinized cassava powder is mixed into the soil.

[0034] It should be noted that the above soil anti-seepage improvement method provided by the present application is suitable for all loess. In order to detect the anti-seepage improvement effect of the gelatinized cassava powder on the soil, the soil used in the subsequent examples and comparative examples of the present application is L2 loess in Zhengning County, Gansu.

[0035] The content of the present application will be specifically described below through the following examples and comparative examples.

[0036] Example 1 A soil anti-seepage improvement method based on gelatinized cassava powder, comprising the following steps: S1, preparing gelatinized cassava powder: mixing the cassava powder and water in a mass ratio of 1:1 based on the absolute dry cassava powder to obtain cassava paste, and then adding boiling water with a mass of 2 times that of the cassava powder to gelatinize the cassava powder to obtain gelatinized cassava powder.

[0037] S2, based on the absolute dry soil and the absolute dry cassava powder, the gelatinized cassava powder is mixed into the soil in a mass ratio of soil to cassava powder of 100:5, mixed with water, compacted, and the water content of the soil is controlled at 20%, and the compaction degree is 80%.

[0038] Example 2 A soil anti-seepage improvement method based on gelatinized cassava powder, comprising the following steps: S1, preparing gelatinized cassava powder: mixing the cassava powder and water in a mass ratio of 1:1 based on the absolute dry cassava powder to obtain cassava paste, and then adding boiling water with a mass of 2 times that of the cassava powder to gelatinize the cassava powder to obtain gelatinized cassava powder.

[0039] S2, based on the absolute dry soil and the absolute dry cassava powder, the gelatinized cassava powder is mixed into the soil in a mass ratio of soil to cassava powder of 100:4, mixed with water, compacted, and the water content of the soil is controlled at 20%, and the compaction degree is 80%.

[0040] Example 3 A soil anti-seepage improvement method based on gelatinized cassava powder, comprising the following steps: S1, preparing gelatinized cassava powder: taking the absolute dry cassava powder as the standard, mixing the cassava powder and water at a mass ratio of 1:1 to obtain cassava paste, then adding 2 times the mass of boiling water to the cassava powder to gelatinize the cassava powder, and obtaining the gelatinized cassava powder.

[0041] S2, taking the absolute dry soil and the absolute dry cassava powder as the standard, mixing the gelatinized cassava powder into the soil at a mass ratio of 100:6 of the soil to the cassava powder, uniformly mixing with water, compacting, controlling the water content of the soil to be 20%, and controlling the compactness to be 80%.

[0042] In order to further illustrate the technical effects of the present application, the present application also sets up comparative examples, which are as follows: Comparative Example 1 A soil anti-seepage improvement method based on gelatinized cassava powder, comprising the following steps: S1, preparing gelatinized cassava powder: taking the absolute dry cassava powder as the standard, mixing the cassava powder and water at a mass ratio of 1:1 to obtain cassava paste, then adding 2 times the mass of boiling water to the cassava powder to gelatinize the cassava powder, and obtaining the gelatinized cassava powder.

[0043] S2, taking the absolute dry soil and the absolute dry cassava powder as the standard, mixing the gelatinized cassava powder into the soil at a mass ratio of 100:2 of the soil to the cassava powder, uniformly mixing with water, compacting, controlling the water content of the soil to be 20%, and controlling the compactness to be 80%.

[0044] Comparative Example 2 A soil anti-seepage improvement method based on gelatinized cassava powder, comprising the following steps: S1, preparing gelatinized cassava powder: taking the absolute dry cassava powder as the standard, mixing the cassava powder and water at a mass ratio of 1:1 to obtain cassava paste, then adding 2 times the mass of boiling water to the cassava powder to gelatinize the cassava powder, and obtaining the gelatinized cassava powder.

[0045] S2, taking the absolute dry soil and the absolute dry cassava powder as the standard, mixing the gelatinized cassava powder into the soil at a mass ratio of 100:0.5 of the soil to the cassava powder, uniformly mixing with water, compacting, controlling the water content of the soil to be 20%, and controlling the compactness to be 80%.

[0046] Comparative Example 3 Compared with Example 1, the difference lies in that no gelatinized cassava powder is mixed, and only the plain soil is used to test the anti-seepage performance.

[0047] Comparative Example 4 Compared with Example 1, the difference lies in that the cassava powder is not gelatinized.

[0048] A soil anti-seepage improvement method based on cassava powder, comprising the following steps: The absolute dry soil and the absolute dry cassava powder are mixed according to the mass ratio of soil, cassava powder and water 100:5:20, and then compacted, so that the water content of the soil is controlled to be 20%, and the compactness is controlled to be 80%.

[0049] Comparative Example 5 Compared with Example 1, the difference lies in that the cassava powder is not gelatinized.

[0050] A soil anti-seepage improvement method based on cassava powder, comprising the following steps: The absolute dry soil and the absolute dry cassava powder are mixed according to the mass ratio of soil, cassava powder and water 100:5:20, and then compacted, so that the water content of the soil is controlled to be 20%, and the compactness is controlled to be 85%.

[0051] Comparative Example 6 Compared with Example 1, the difference lies in that the cassava powder is not gelatinized.

[0052] A soil anti-seepage improvement method based on cassava powder, comprising the following steps: The absolute dry soil and the absolute dry cassava powder are mixed according to the mass ratio of soil, cassava powder and water 100:5:20, and then compacted, so that the water content of the soil is controlled to be 20%, and the compactness is controlled to be 95%.

[0053] The soil anti-seepage improvement method provided by the application still has a significant anti-seepage effect under the condition of low compactness, Figure 1 The soil anti-seepage improvement method provided by the application still has a significant anti-seepage effect under the condition of low compactness, Figure 1 It can be known that, in the case that the compactness is only 80%, the permeability coefficient is reduced from 2.41*10 -4 cm / s of the soil in Comparative Example 3 to 1.35*10 -6 cm / s of the anti-seepage improved soil in Example 1, which is reduced by more than two orders of magnitude, and the dependence of the project on the compactness is significantly weakened. Figure 2 The soil permeability coefficients of the soil in Comparative Example 3 and the cassava powder improved soil in Comparative Example 4 are compared with the change of the compactness, and it can be known that Figure 2 The permeability coefficient of the soil with the cassava powder not gelatinized is significantly different from that of the soil, so the cassava powder not gelatinized cannot positively affect the anti-seepage effect of the soil.

[0054] Figure 3 The soil permeability coefficient changes with the change of the addition amount of the cassava powder, and compared with the addition amount of the soil and the cassava powder 100:5 in Example 1, the addition amount of the cassava powder in Comparative Example 1 and Comparative Example 2 cannot achieve the effect of significantly reducing the soil permeability coefficient, and the anti-seepage effect of the soil is not up to standard. Comparative Examples 4 to 6 use the cassava powder not gelatinized to mix with the soil, and even if the compactness is increased from 80% to 95%, the saturated permeability coefficient of the soil is not affected.

[0055] Pore structure modification: Figure 4 The pore distribution comparison chart of the modified soil of Example 1 of the present application and the raw soil of Comparative Example 1. From Table 1 and Figure 4 It can be seen that the incorporation of the gelatinized cassava powder fills a large number of dominant water-permeable pores (>26 μm) in the loess, so that the proportion of the dominant water-permeable pores is reduced from 51% to 31%, thereby greatly reducing the saturated permeability coefficient of the sample. The mechanism of "skeleton filling-particle adhesion" is formed, the cassava powder particles exist in the soil as skeleton particles, promote the densification of the microstructure, and at the same time, reduce the permeability coefficient through the large pore plugging effect. At the same time, the small soil particles are adhered around the large particles, improving the stability of the pores in the sample and limiting the flow of water. At the same time, the modified soil technology has low requirements on the equipment, and takes into account the engineering performance and construction feasibility.

[0056] Table 1 Proportion of three types of pores and pore size difference of raw soil and anti-seepage modified soil with 80% compaction Note: The pore size difference in the table is calculated based on the pore volume of the modified soil.

[0057] Figure 5 The microstructure difference comparison chart of the anti-seepage modified soil of Example 1 of the present application and the raw soil of Comparative Example 1. From Figure 5 It can be seen that when only the raw soil of Comparative Example 1 exists, there are a large number of large pore structures in the loess, and the gelatinized cassava powder fills the large pore structure in the loess with the incorporation of the gelatinized cassava powder, thereby effectively improving the anti-seepage effect of the soil.

[0058] Figure 6 The soil-water characteristic curve comparison chart of the modified soil of Example 1 of the present application and the raw soil of Comparative Example 1. From Figure 6 It can be seen that under the condition of 80% compaction, under the condition of higher water content (>20%), the matric suction of the modified soil is smaller than that of the raw soil under the same water content, which means that the water potential difference of the modified soil is lower than that of the raw soil on the boundary in contact with water during the permeation process, which will reduce the permeation capacity of the modified soil, which is manifested as a decrease in the permeability coefficient; on the contrary, under the condition of low water content (<20%), the water potential difference of the modified soil is greater than that of the raw soil, which indicates that the modified soil is not easy to lose water under relatively dry conditions. Overall, the soil-water characteristic curve of the modified soil tends to be smooth, showing the improvement of the water content stability and the anti-permeation performance of the modified soil under high water content conditions.

[0059] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method for soil seepage prevention and improvement based on gelatinized cassava flour, characterized in that, Includes the following steps: Preparation of gelatinized cassava flour; Gelatinized cassava flour is mixed into the soil, water is added and mixed evenly, and then compacted. The cassava flour particles fill the soil pores and bind the soil particles together, resulting in impermeable and improved soil.

2. The soil seepage prevention and improvement method based on gelatinized cassava flour according to claim 1, characterized in that, Based on absolutely dry soil and absolutely dry cassava flour, the mass ratio of the soil to the cassava flour is 50:2~3.

3. The soil seepage prevention and improvement method based on gelatinized cassava flour according to claim 2, characterized in that, The mass ratio of soil to cassava flour is 20:

1.

4. The soil seepage prevention and improvement method based on gelatinized cassava flour according to claim 1, characterized in that, After compaction, the soil moisture content is 18%~20%.

5. The soil seepage prevention and improvement method based on gelatinized cassava flour according to claim 1, characterized in that, After compaction, the soil compaction degree is 80%~85%.

6. The soil seepage prevention and improvement method based on gelatinized cassava flour according to claim 1, characterized in that, After compaction, the soil permeability coefficient is 1.35 × 10⁻⁶. -6 cm / s ~ 1.28 × 10 -6 cm / s.

7. The soil seepage prevention and improvement method based on gelatinized cassava flour according to claim 1, characterized in that, The method for preparing the gelatinized cassava flour includes the following steps: mixing cassava flour with water to obtain cassava paste, then adding boiling water to gelatinize the cassava flour to obtain gelatinized cassava flour.

8. The soil seepage prevention and improvement method based on gelatinized cassava flour according to claim 6, characterized in that, Based on oven-dried cassava flour, the mass ratio of the cassava flour to water is 1:1~2.

9. The soil seepage prevention and improvement method based on gelatinized cassava flour according to claim 6, characterized in that, Based on the amount of absolutely dried cassava flour, the mass ratio of the cassava flour to boiling water is 1:2~4.

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