Ion barrier wall material and construction method applied to high-doped alkali slag roadbed

Abstract

This invention discloses an ion-retaining wall material and construction method for use on both sides of a roadbed with high alkaline residue content. The ion-retaining wall material includes organic bentonite, a polymer hydrogel, and water. The polymer hydrogel is anionic polyacrylamide, low-polymerization polyvinyl alcohol particles, and polyvinylpyrrolidone. Using this ion-retaining wall material to form an ion-retaining wall can block the migration of ions in the roadbed, thereby achieving soil stabilization and foundation strengthening, protecting the environment, and promoting the large-scale application of alkaline residue. This overcomes the problem that heavy metal ions and strong electrolytes in roads with high alkaline residue content migrate and diffuse into farmland and arable soil due to concentration differences, causing soil pollution. Furthermore, the diffusion of ions can make the originally stable alkaline residue roadbed prone to cracking and collapse.

Description

Technical Field

[0001] This invention belongs to the field of building materials, specifically relating to an ion retaining wall and its construction method for use in high-content alkaline slag subgrade soil for rural roads or adjacent farmland. Background Technology

[0002] my country has abundant salt reserves and its salt chemical industry has developed rapidly. However, with increasing production, the problem of waste disposal from the salt and alkali chemical industry has become increasingly serious. The most serious problem is the slag produced by the ammonia-soda process, also known as white mud, of which my country's annual production has exceeded 10 million tons. A plant producing 800,000 tons of soda ash annually incurs approximately 10 million yuan in costs for waste disposal each year. Typically, the alkali slag is disposed of by surface dumping, resulting in large deposits forming a "white sea" that pollutes the surrounding waters and indicates a severe lack of resource utilization.

[0003] Based on this, the applicant is committed to the widespread application of high-content alkali slag soil in road paving, increasing the utilization of alkali slag and expanding the engineering application scope of high-content alkali slag subgrade soil. Currently, using alkali slag as a road construction material results in the large-scale consumption of alkali slag, but the environmental problems it brings are also very obvious. Due to the migration effect of concentration difference, heavy metal ions in high-content alkali slag roads, such as chloride and sulfate ions formed by strong electrolytes, diffuse into farmland and cultivated soil, causing soil pollution. Moreover, due to ion diffusion, the originally stable alkali slag subgrade becomes prone to cracking and collapse. Summary of the Invention

[0004] The purpose of this invention is to provide an ion barrier material and its construction method for both sides of a roadbed with high alkali residue content. The ion barrier material is used to construct ion barriers on both sides of the roadbed with high alkali residue content to block the migration of ions caused by the concentration difference of alkali residue in the roadbed, thereby achieving the functions of soil stabilization, foundation strengthening, and environmental protection.

[0005] To address the problems of existing technologies, the technical solution adopted in this invention is as follows: an ion-retaining wall material applied to both sides of a roadbed with high alkali content, composed of organic bentonite, anionic polyacrylamide, low-polymerization degree polyvinyl alcohol particles, polyvinylpyrrolidone, and water.

[0006] By weight, the components are: 0.60-0.80 parts organic bentonite, 0.005-0.015 parts anionic polyacrylamide, 0.004-0.006 parts low-polymerization polyvinyl alcohol, 0.004-0.006 parts polyvinylpyrrolidone, and 0.22-0.30 parts water.

[0007] Based on the above scheme, as a preferred option, the following components are used: 0.71 parts organic bentonite, 0.01 parts anionic polyacrylamide, 0.005 parts low-polymerization polyvinyl alcohol, 0.005 parts polyvinylpyrrolidone, and 0.27 parts water.

[0008] Based on the above scheme, as a preferred option, the free swelling degree of organic bentonite particles is not less than 14 ml / g. Organic bentonite expands in volume after absorbing water, forming a dense impermeable layer that prevents water and other liquids from seeping through the soil to the lower layers. Therefore, the swelling rate of bentonite is one of the important indicators for evaluating its impermeability.

[0009] The swelling rate refers to the ratio of the volume expansion of organic bentonite after absorbing water to its initial dry volume. A higher swelling rate means greater expansion of the bentonite after water absorption, resulting in a denser impermeable layer and better impermeability. Therefore, when selecting bentonite as a soil impermeable material, it is necessary to choose bentonite with an appropriate swelling rate based on actual needs to ensure its impermeability meets requirements. Furthermore, when using bentonite, attention should be paid to changes in its swelling rate to avoid poor impermeability due to excessively high or low swelling rates.

[0010] Based on the above scheme, as a preferred option, the anionic polyacrylamide has a molecular weight of not less than 18 million and is in solid granular form.

[0011] Based on the above scheme, as a preferred option, the low degree of polymerization polyvinyl alcohol has a molecular weight of 30,000-35,000 and a degree of alcoholysis of 80.

[0012] Based on the above scheme, as a preferred embodiment, the polyvinylpyrrolidone monomer polymer has a molecular weight of 20,000 or more and is in the form of a solid crystalline powder.

[0013] A construction method for ion-retaining walls on both sides of a roadbed with high alkali content slag, utilizing the aforementioned ion-retaining wall material, includes:

[0014] (1) Ground treatment, marking the roadbed paving red line, and setting up ion barrier red line adjacent to the red line;

[0015] (2) Excavate trenches, excavate trenches along the designed red line of the ion retaining wall and level the bottom soil layer of the trenches;

[0016] (3) The organic bentonite, anionic polyacrylamide, low-polymerization polyvinyl alcohol particles, and polyvinylpyrrolidone mixture are sequentially filled into the pit, then watered and compacted. This process is repeated until the design requirements are met.

[0017] Alternatively, organic bentonite can be mixed with anionic polyacrylamide, low-polymerization polyvinyl alcohol granules, and polyvinylpyrrolidone, then laid in layers, watered and compacted, and this process can be repeated until the design requirements are met.

[0018] (4) The top of the ion retaining wall is level with or slightly higher than the bottom of the roadbed. The depth of the ion retaining wall is 0.2-1.2 times the height of the roadbed, and the width is 0.05-0.15 times the width of the roadbed.

[0019] When backfilling the last layer of ion barrier material, it is necessary to ensure that the compaction degree reaches more than 92% of the maximum compaction degree.

[0020] Based on the above scheme, as a preferred option, when laying in layers, the thickness of each layer is 15-25cm.

[0021] Based on the above scheme, as a preferred option, trench excavation should be carried out after the roadbed red line survey is completed and the original ground surface is treated.

[0022] Based on the above scheme, as a preferred option, when treating the interface between the alkali residue roadbed and other roadbeds, the ion retaining wall needs to exceed the cross-sectional length of the roadbed by 0.5-1.2 times.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. Enhance the stability of alkali slag subgrade soil: The solubility of some sulfate substances is affected by concentration and temperature. Therefore, sulfate-containing alkali slag subgrade soil is prone to swelling and cracking. Ion barrier walls can reduce the risk of cracking caused by the leaching of sulfate substances in alkali slag, thereby increasing the stability and durability of alkali slag subgrade soil.

[0025] 2. Reduce the environmental impact of alkali residue on surrounding farmland: In view of the potential environmental problems caused by most highways crossing farmland, ion retaining walls can effectively isolate the migration of metal ions and salt ions in alkali residue, reducing the environmental impact of large-scale use of alkali residue on farmland.

[0026] 3. This invention uses organic bentonite and high molecular polymers, and the high molecular polymer dosage is low, making construction simple and easy. Compared with cement materials, it overcomes the problem that the cement hydration process itself contains OH ions that overflow, which, when combined with alkali residue, can easily cause the surrounding soil to effloresce. This invention greatly reduces the risk of secondary efflorescence in the soil.

[0027] 4. This invention uses organic bentonite, which has better corrosion resistance: Organic bentonite has good resistance to acids, alkalis, and corrosion, and can maintain its impermeability for a long time in acidic or alkaline environments. Alkali slag roadbeds belong to alkaline environments.

[0028] 5. This invention uses organic bentonite, which has better waterproof performance: Because organic bentonite molecules contain a large number of hydrophobic groups, they can effectively improve their waterproof performance and have better applicability to projects with high waterproof requirements. Drainage ditches will be set in the top part of the roadbed retaining wall, and there will be surface runoff, so engineering materials with waterproof requirements are required.

[0029] 6. This invention uses organic bentonite, which has stronger bonding strength: Organic bentonite molecules contain more hydrogen bonds and van der Waals forces, which can form stronger bonding with surrounding particles, thereby improving its seepage prevention performance. It also has a stronger ability to contain metal ions released from the interior of alkali slag. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of ion retaining walls laid on both sides of the roadbed.

[0031] In the diagram: 1. Ground, 2. Roadbed, 3. Ion barrier. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to the embodiments.

[0033] The ion barrier material, by weight, contains 0.60-0.80 parts of organic bentonite, 0.005-0.015 parts of anionic polyacrylamide, 0.004-0.006 parts of low-polymerization polyvinyl alcohol, 0.004-0.006 parts of polyvinylpyrrolidone, and 0.22-0.30 parts of water.

[0034] For ion barrier materials, the specific components, by mass parts, include but are not limited to the following:

[0035] (1) 0.60 parts of organic bentonite, 0.005 parts of anionic polyacrylamide, 0.004 parts of low degree of polymerization polyvinyl alcohol, 0.004 parts of polyvinylpyrrolidone, and 0.22 parts of water.

[0036] (2) 0.80 parts of organic bentonite, 0.015 parts of anionic polyacrylamide, 0.006 parts of low degree of polymerization polyvinyl alcohol, 0.006 parts of polyvinylpyrrolidone, and 0.30 parts of water.

[0037] (3) 0.71 parts organic bentonite, 0.01 parts anionic polyacrylamide, and 0.005 parts low-polymerization polyvinyl alcohol.

[0038] 0.005 parts polyvinylpyrrolidone, 0.27 parts water.

[0039] Among them, component (3) is the best when the ion barrier is constructed. Therefore, component (3) is selected as the ion barrier material used in the various embodiments below.

[0040] The measurement method was as follows: In Example 1, the center of the roadbed was taken as the origin, and 10 coordinate points were randomly selected within a 1.5m width outward from the retaining wall to collect soil samples. In Examples 2 and 3, the coordinate points were the same as in Example 1. Soil leachate was prepared with a liquid-to-solid ratio of 2.1, and the leachate was filtered through a 0.025mm pinhole filter. The resulting leachate was used to measure the soil Cl- content. - SO4 -2 Ion concentration (unit: 10) -3 The Mol / L H value and soil solution electrical conductivity (refer to EU standard NEN-7375, 2004) are averaged and included in the table.

[0041] Note: The chloride ion concentration of the original soil leachate was 1.53, the sulfate ion concentration was 1.44, the pH was 7.2, and the static CT value was 111. The experimental CT value is greatly affected by factors such as temperature, so it is only used as auxiliary reference data.

[0042] Comparative Example 0

[0043] Similar to the example, this is a ramp project with a roadbed height of 1.5m and a width of 6m. The original geological conditions are the same. The comparative example does not have an ion barrier. The measurement points are the same as the coordinate points of Example 1.

[0044] Table 1. Ion concentration, pH value, and electrical conductivity (CT) of soil on both sides of the roadbed within 56 days.

[0045]

[0046] Example 1

[0047] like Figure 1 As shown, this embodiment provides an ion retaining wall material and its construction method for both sides of a roadbed with high alkali content slag, including the following steps:

[0048] Raw material preparation: Weigh the following components according to the mass percentages: 1. Organic bentonite (oven-dry state) 0.71 parts; 2. Anionic polyacrylamide 0.01 parts; 3. Low degree of polymerization polyvinyl alcohol 0.005 parts; 4. Polyvinylpyrrolidone 0.005 parts; 5. Water 0.27 parts.

[0049] (1) Ground treatment, marking the roadbed paving red line, and setting up ion barrier red line adjacent to the red line;

[0050] (2) Excavate trenches, excavate trenches along the designed red line of the ion retaining wall and level the bottom soil layer of the trenches;

[0051] (3) The organic bentonite, anionic polyacrylamide, low-polymerization polyvinyl alcohol granules, and polyvinylpyrrolidone mixture are sequentially filled into the pit, then watered and compacted. This process is repeated layer by layer until the design requirements are met. The organic bentonite is laid to a thickness of 20 cm each time, followed by the anionic polyacrylamide, low-polymerization polyvinyl alcohol granules, and polyvinylpyrrolidone mixture.

[0052] (4) The top of the ion retaining wall is flush with the bottom of the roadbed. The depth of the ion retaining wall is 0.2 times the height of the roadbed, and the width is 0.1 times the width of the roadbed.

[0053] The test results are shown in the table below:

[0054] Table 2. Ion concentration, pH value, and electrical conductivity (CT) of soil on both sides of the roadbed within 56 days.

[0055]

[0056]

[0057] Example 2

[0058] This embodiment provides an ion-retaining wall material and its construction method for both sides of a high-dosage alkaline slag roadbed. After construction, the depth of the retaining wall is 0.5 times the roadbed height, and the width is 0.1 times the roadbed width. Other implementation details are as described in Embodiment 1.

[0059] The test results are shown in the table below:

[0060] Table 2. Ion concentration, pH value, and electrical conductivity (CT) of soil on both sides of the roadbed within 56 days.

[0061]

[0062] Example 3

[0063] This embodiment provides an ion-retaining wall material and its construction method for both sides of a high-dosage alkaline slag roadbed. After construction, the retaining wall has a depth of 1 times the roadbed height and a width of 0.1 times the roadbed width. Other implementation details are as described in Embodiment 1.

[0064] The test results are shown in the table below:

[0065] Table 2. Ion concentration, pH value, and electrical conductivity (CT) of soil on both sides of the roadbed within 256 days.

[0066]

[0067] Example 4

[0068] This embodiment provides an ion-retaining wall material and its construction method for both sides of a high-dosage alkaline slag roadbed. After construction, the depth of the retaining wall is 1.2 times the roadbed height, and the width is 0.1 times the roadbed width. For other implementation details, refer to Embodiment 1.

[0069] The test results are shown in the table below:

[0070] Table 2. Ion concentration, pH value, and electrical conductivity (CT) of soil on both sides of the roadbed within 56 days.

[0071]

[0072]

[0073] The application scope of the ion barrier is not limited to the application scope of high-content construction waste roadbed soil, but can also be applied to the disposal projects of other industrial waste residues and materials with internal and external ion concentration differences.

[0074] When constructing road cuts, they can be constructed together with the drainage ditches on both sides of the road to avoid repeated excavation of trenches.

Claims

1. An ion-blocking wall material applied to both sides of a roadbed with high alkali content slag, characterized in that, It is composed of organic bentonite, anionic polyacrylamide, low-polymerization polyvinyl alcohol particles, polyvinylpyrrolidone, and water. By weight, the composition includes 0.60-0.80 parts of organic bentonite, 0.005-0.015 parts of anionic polyacrylamide, 0.004-0.006 parts of low-polymerization polyvinyl alcohol particles, 0.004-0.006 parts of polyvinylpyrrolidone, and 0.22-0.30 parts of water. The anionic polyacrylamide has a molecular weight of not less than 18 million and is in solid granular form; the polyvinylpyrrolidone has a molecular weight of more than 20,000 and is in solid crystalline powder form; the low degree of polymerization polyvinyl alcohol granules have a molecular weight of 30,000-35,000 and a degree of alcoholysis of 80.

2. The ion barrier material for use on both sides of a roadbed with high alkali content as described in claim 1, characterized in that, 0.71 parts organic bentonite, 0.01 parts anionic polyacrylamide, 0.005 parts low-polymerization degree polyvinyl alcohol particles, 0.005 parts polyvinylpyrrolidone, and 0.27 parts water.

3. The ion barrier material for use on both sides of a roadbed with high alkali content as described in claim 1, characterized in that, The free expansion degree of organic bentonite particles is not less than 14 ml / g.

4. A construction method for ion-retaining walls on both sides of a roadbed with high alkali content, comprising using the ion-retaining wall material as described in any one of claims 1-3, characterized in that, include: (1) Ground treatment, marking the roadbed paving red line, and setting up ion retaining wall red line adjacent to the red line; (2) Excavate trenches along the designed red line of the ion retaining wall and level the bottom soil layer of the trench; (3) Fill the pit with organic bentonite, anionic polyacrylamide, low-polymerization polyvinyl alcohol particles and polyvinylpyrrolidone in sequence, then sprinkle water and compact it. Repeat this layering process until the design requirements are met. Alternatively, organic bentonite can be mixed with anionic polyacrylamide, low-polymerization polyvinyl alcohol granules, and polyvinylpyrrolidone, then laid in layers, watered and compacted, and this process can be repeated until the design requirements are met. (4) The top of the ion retaining wall is level with or slightly higher than the bottom of the roadbed. The depth of the ion retaining wall is 0.2-1.2 times the height of the roadbed, and the width is 0.05-0.15 times the width of the roadbed.

5. A construction method for ion retaining walls on both sides of a high-dosage alkaline slag roadbed according to claim 4, characterized in that, When laying in layers, the thickness of each layer should be 15-25cm.

6. A construction method for ion retaining walls on both sides of a high-dosage alkaline slag roadbed according to claim 4, characterized in that, Trench excavation must be carried out after the roadbed red line survey is completed and the original ground surface has been treated.

7. A construction method for ion retaining walls on both sides of a high-dosage alkaline slag roadbed according to claim 4, characterized in that, When treating the interface between alkaline residue roadbed and other roadbeds, the ion retaining wall needs to exceed the cross-sectional length of the roadbed by 0.5-1.2 times.

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