A gravel soil solidifying agent, its preparation method and its usage method

Abstract

The present invention discloses a solidifying agent for crushed stone soil, a preparation method thereof and a using method thereof. The solidifying agent for crushed stone soil is composed of mixture A and mixture B. Mixture A includes raw materials in the following weight parts: 2 to 8 parts of polyanionic cellulose, 3 parts of sodium octenyl succinate starch and 1000 parts of water. Mixture B includes raw materials in the following weight parts: 1 to 5 parts of calcium hydroxide and 1 to 5 parts of plaster of Paris. The solidifying agent for crushed stone soil of the present invention is energy-saving and environment-friendly, has a small dosage, is simple in construction and has a good reinforcement effect on crushed stone soil. The preparation method of the solidifying agent for crushed stone soil of the present invention has low cost and is suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil reinforcement, and particularly relates to a gravel soil solidifying agent, a preparation method and a using method thereof. Background Art

[0002] Loess is widely distributed in the northeast, northwest and north China regions of our country, and has the characteristics of deep sedimentation thickness, long duration and wide distribution range. Usually, a large amount of gravel with different particle sizes is doped in the loess, or in order to meet the needs of engineering construction, a large amount of gravel is artificially incorporated, which is called gravel soil. Due to the weak cementation between loess particles and between loess and gravel, and the loose accumulation and other characteristics, it is extremely vulnerable to erosion under rainfall conditions to form a state of soil-rock separation, resulting in the damage of roadbed slopes or triggering natural disasters such as landslides and mudslides. In addition, due to the large pore structure, low strength and easy collapsibility of gravel loess when encountering water, the uneven settlement of the roadbed is aggravated, and cracks caused by uneven stress are everywhere on rural concrete roads, seriously affecting ecological environment protection and engineering construction. Therefore, when developing it, it is necessary to reinforce and improve the soil to ensure that the soil properties meet the engineering requirements.

[0003] Common physical methods include earthwork strengthening, densification and dehydration, etc. When using these physical methods to reinforce the soil, problems such as the need for a large floor area, easy generation of huge noise and vibration, and insignificant effects are often faced.

[0004] In recent years, chemical reinforcement technologies have been continuously developed, and a variety of new chemical reinforcing agents developed for different types of soils have emerged one after another. However, the current types of chemical reinforcing agents are still mainly soil reinforcing agents, mainly for the improvement of loess, sandy soil and silt soil; and because gravel soil contains a large amount of gravel, its chemical composition, contact method, etc. are completely different from ordinary soil, and it is not easy to form a strong connection force between soil particles and gravel, and the compatibility is poor. Therefore, general soil reinforcing agents have a very weak reinforcing effect on gravel soil and cannot achieve the expected effect of reinforcing gravel soil. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a gravel soil solidifying agent, a preparation method and a using method thereof. The technical problems to be solved by the present invention are realized through the following technical solutions:

[0006] In the first aspect, the present invention provides a gravel soil solidifying agent, which is composed of mixture A and mixture B;

[0007] The mixture A includes the following raw materials in parts by weight: 2-8 parts of polyanionic cellulose, 3 parts of sodium octenyl succinate starch and 1000 parts of water;

[0008] The mixture B comprises the following raw materials in parts by weight: 1 to 5 parts of calcium hydroxide and 1 to 5 parts of plaster of Paris.

[0009] In one embodiment of the present invention, the dosage of the mixture A is 12% of the mass of the crushed stone soil to be solidified, and the dosage of the mixture B is 9% of the mass of the crushed stone soil to be solidified.

[0010] In one embodiment of the present invention, the relative molecular weight of the polyanionic cellulose is 1,000,000.

[0011] Second, the present invention provides a preparation method of a solidifying agent for crushed stone soil, comprising the following steps:

[0012] Mix and grind 2 to 8 parts of polyanionic cellulose and 3 parts of octenyl succinic anhydride starch sodium, add 1000 parts of water and mix. After stirring and standing, mixture A is obtained;

[0013] Mix and grind 1 to 5 parts of calcium hydroxide and 1 to 5 parts of plaster of Paris to obtain mixture B;

[0014] All raw materials are in parts by weight.

[0015] In one embodiment of the present invention, the time for stirring and standing is: stirring for 15 to 30 minutes and standing for 2 hours.

[0016] In one embodiment of the present invention, the dosage of the mixture A is 12% of the mass of the crushed stone soil to be solidified, and the dosage of the mixture B is 9% of the mass of the crushed stone soil to be solidified.

[0017] In one embodiment of the present invention, the relative molecular weight of the polyanionic cellulose is 1,000,000.

[0018] Third, the present invention provides a using method of a solidifying agent for crushed stone soil, and the solidifying agent for crushed stone soil is the solidifying agent for crushed stone soil described in any one of claims 1 to 3 or the solidifying agent for crushed stone soil prepared by the preparation method described in any one of claims 4 to 7;

[0019] Add the mixture A into the crushed stone soil to be solidified according to 12% of the mass of the crushed stone soil to be solidified, stir and stand;

[0020] Then add the mixture B into the crushed stone soil to be solidified containing the polymer solution of the mixture A according to 9% of the mass of the crushed stone soil to be solidified.

[0021] In one embodiment of the present invention, the standing time is 12 to 24 h.

[0022] Compared with the prior art, the beneficial effects of the present invention:

[0023] The solidifying agent for the novel environmentally friendly crushed stone soil body of the present invention is energy-saving and environmentally friendly, with less dosage, simple construction, and good reinforcement effect on crushed stone soil.

[0024] The preparation method of the solidifying agent for the crushed stone soil body of the present invention has low cost and is suitable for large-scale production.

[0025] When the solidifying agent for the crushed stone soil body of the present invention is applied, sodium octenyl succinate starch will accelerate the dissolution time of polyanionic cellulose and ensure the stability of the aqueous solution. The aqueous solution of polyanionic cellulose can strongly wrap the crushed stone soil particles, effectively resist the erosion and damage of water to the crushed stone soil, and at the same time increase the frictional strength between particles; gypsum will generate a stronger spatial connection effect between the crushed stones and soil particles, making the crushed stones and soil tightly cemented together to form an integral body that is not easily dispersed; calcium hydroxide can also absorb the CO2 gas generated in the soil, continuously form CaCO3 precipitation, further fill the pores, and enhance the compactness of the crushed stone soil, thereby improving the water stability and strength performance of the crushed stone soil. Therefore, the solidifying agent for the crushed stone soil body of the present invention can establish good connection ability between the crushed stones and soil particles, enhance the cementing ability between the soil and stones; and can also absorb the carbon dioxide gas released in the soil, induce the formation of calcium carbonate precipitation, greatly improve the water stability and strength of the crushed stone soil; it not only solves the current situation that the crushed stone soil is easily eroded and the soil and stones are separated, but also greatly improves the strength and water stability of the crushed stone soil. Description of the Drawings

[0026] Figure 1 It is the water stability test data graph of Examples 1-3 and the control group;

[0027] Figure 2 It is the unconfined compressive strength test data graph of Examples 1-3 and the control group. Detailed Embodiments

[0028] The following further describes the present invention in detail with specific embodiments, but the implementation manners of the present invention are not limited thereto.

[0029] In order to solve the problem that there is currently a lack of chemical reinforcing agents for crushed stone soil bodies, and the general soil reinforcing agents have very weak reinforcing effects on crushed stone soil and cannot achieve the expected effect of reinforcing crushed stone soil, the present invention provides a preparation method and a use method of a solidifying agent for crushed stone soil bodies.

[0030] In the first aspect, the solidifying agent for the crushed stone soil body provided by the present invention is composed of mixture A and mixture B; mixture A includes the following raw materials in parts by weight: 2-8 parts of polyanionic cellulose, 3 parts of sodium octenyl succinate starch, and 1000 parts of water; mixture B includes the following raw materials in parts by weight: 1-5 parts of calcium hydroxide, 1-5 parts of gypsum.

[0031] Among them, polyanionic cellulose has good water loss reducing property and stability, which can provide a moisture basis for subsequent chemical reactions. In addition, polyanionic cellulose dissolved in water has adhesive properties, which can enhance the connection ability of soil and stone. Preferably, the relative molecular weight of polyanionic cellulose in the present invention is 1 million.

[0032] Since polyanionic cellulose will agglomerate when dissolved in water and cannot be quickly dissolved, and the complete dissolution time is up to more than 48 hours. The addition of sodium octenyl succinate starch used in the present invention enables polyanionic cellulose to be quickly dissolved at room temperature (within 1.5 hours), and the formed aqueous solution is stable without precipitation.

[0033] The gypsum in the gravel soil solidifying agent of the present invention can generate a gelling substance, dihydrate gypsum (CaSO4·2H2O), when encountering water. With the hydration and evaporation of free water, the gelling substance undergoes condensation and hardening, the plasticity decreases, and a stronger spatial connection effect is generated between the gravel and soil particles, making the gravel and soil tightly cemented together to form an integral body that is not easily dispersed.

[0034] Calcium hydroxide in the gravel soil solidifying agent of the present invention can also absorb CO2 gas generated in the soil, continuously form CaCO3 precipitation, further fill the pores, enhance the compactness of the gravel soil, thereby improving the water stability and strength performance of the gravel soil, and enabling it to better meet the engineering requirements.

[0035] It should be noted that in the gravel soil solidifying agent of the present invention, mixture A and mixture B are each prepared separately according to their respective raw material composition ratios, and are used in proportion according to the mass of mixture A and mixture B and the gravel soil to be solidified during specific use. In addition, for the convenience of use, mixture A can also be first proportioned according to the weight parts of polyanionic cellulose and sodium octenyl succinate starch, and the corresponding weight parts of water are added according to the corresponding ratio during specific use.

[0036] The preferred dosage of the gravel soil solidifying agent of the present invention during use is: the dosage of mixture A is 12% of the mass of the gravel soil to be solidified, and the dosage of mixture B is 9% of the mass of the gravel soil to be solidified.

[0037] In the second aspect, the present invention provides a preparation method of a gravel soil solidifying agent, comprising the following steps:

[0038] Mix and grind 2 - 8 parts of polyanionic cellulose and 3 parts of sodium octenyl succinate starch, add 1000 parts of water and mix. After stirring and standing, mixture A is obtained; the specific stirring and standing time can be stirring for 15 - 30 minutes and standing for 1.5 hours;

[0039] Mix and grind 1 - 5 parts of calcium hydroxide and 1 - 5 parts of gypsum to obtain mixture B;

[0040] All raw materials are in parts by weight.

[0041] The solidifying agent for crushed stone soil prepared by the preparation method of the present invention is two mixtures, mixture A and mixture B, to be used. When used for specific crushed stone soil, the preferred dosages of mixture A and mixture B are: the dosage of mixture A is 12% of the mass of the crushed stone soil to be solidified, and the dosage of mixture B is 9% of the mass of the crushed stone soil to be solidified.

[0042] Furthermore, the relative molecular weight of the polyanionic cellulose used in the present invention is 1 million.

[0043] Thirdly, the embodiment of the present invention also provides a method for using the above-mentioned solidifying agent for crushed stone soil:

[0044] Add mixture A to the crushed stone soil to be solidified at 12% of the mass of the crushed stone soil to be solidified, stir and let stand.

[0045] Then add mixture B to the crushed stone soil to be solidified containing the polymer solution of mixture A at 9% of the mass of the crushed stone soil to be solidified.

[0046] Among them, the standing time after adding mixture A to the crushed stone soil is 12 - 24 h. Preferably 24 h, which can make mixture A evenly distributed in the crushed stone soil.

[0047] The novel environmental protection solidifying agent for crushed stone soil of the present invention is energy-saving and environment-friendly, with less dosage, simple construction and good strengthening effect on crushed stone soil.

[0048] The preparation method of the solidifying agent for crushed stone soil of the present invention has low cost and is suitable for large-scale production.

[0049] The specific principle of the gravel soil solidifying agent for reinforcing the gravel soil when used is as follows: sodium starch octenylsuccinate can accelerate the dissolution time of polyanionic cellulose and ensure the stability of the aqueous solution, so that the aqueous solution of polyanionic cellulose can better act on the gravel soil particles; the aqueous solution of polyanionic cellulose can wrap the gravel and soil particles like a film, because the aqueous solution of anionic cellulose contains a large number of hydrophilic functional groups (-COOH, -OH, -CO-NH2), which can exchange ions with the cations on the surface of the gravel and soil particles, resulting in changes in the electronic layer on the surface of the particles, reducing the thickness of the water film of bound water adsorbed on the surface of the particles, on the one hand, making the polymer material adhere to the particles. The stronger the force, the stronger the wrapping and protective effect, and the more effective it is to resist the erosion and damage of the gravel soil by water. On the other hand, the distance between soil particles is reduced, the arrangement is more closely, and the density is enhanced. At the same time, the contact area between soil particles and soil particles, and between soil particles and gravel is increased. The increase in area will lead to an increase in friction, thereby increasing the friction strength. In addition, the main component of the curing agent, gypsum, can produce a gelling substance, dihydrate gypsum (CaSO4·2H2O), when it comes into contact with water. With the hydration and evaporation of free water, the gelling substance coagulates and hardens, and the plasticity decreases, which produces a stronger spatial connection between the gravel and soil particles, making the gravel and soil tightly bonded together to form a whole that is not easy to disperse. The calcium hydroxide contained in the curing agent can also absorb the CO2 gas produced in the soil, continuously forming CaCO3 precipitation, further filling the pores, and enhancing the density of the gravel soil, thereby improving the water stability and strength performance of the gravel soil, so that it can better meet the engineering needs.

[0050] The following is a detailed description through specific embodiments and experimental tests.

[0051] Example 1

[0052] The gravel soil solidifying agent of this embodiment is composed of mixture A and mixture B; mixture A includes the following raw materials in parts by weight: 2 parts of polyanionic cellulose, 3 parts of sodium starch octenyl succinate and 1000 parts of water; mixture B includes the following raw materials in parts by weight: 5 parts of calcium hydroxide and 1 part of gypsum.

[0053] The preparation method of the crushed stone soil solidifying agent of this embodiment comprises the following steps:

[0054] (1) Weigh the raw materials: 2 kg of polyanionic cellulose, 3 kg of sodium starch octenyl succinate, 1000 kg of water, 5 kg of calcium hydroxide, and 1 kg of plaster of Paris. The relative molecular weight of the polyanionic cellulose is 1 million, and the molecular weight of the sodium starch octenyl succinate is 902.93.

[0055] (2) Mix and grind the separately weighed polyanionic cellulose and sodium octenyl succinate starch, add water and mix, stir for 15 min, and let stand for 2 h to obtain mixture A;

[0056] (3) Mix and grind the separately weighed calcium hydroxide and gypsum to obtain mixture B; mixture A and mixture B together constitute the crushed stone soil solidifying agent of the present invention.

[0057] Example 2

[0058] The crushed stone soil solidifying agent of this example is composed of mixture A and mixture B; mixture A includes the following raw materials in parts by weight: 5 parts of polyanionic cellulose, 3 parts of sodium octenyl succinate starch, and 1000 parts of water; mixture B includes the following raw materials in parts by weight: 3 parts of calcium hydroxide and 3 parts of gypsum.

[0059] The preparation method of the crushed stone soil solidifying agent of this example includes the following steps:

[0060] (1) Weigh the raw materials: 5 kg of polyanionic cellulose, 3 kg of sodium octenyl succinate starch, 1000 kg of tap water, 3 kg of calcium hydroxide, and 3 kg of gypsum;

[0061] (2) Mix and grind the separately weighed polyanionic cellulose and sodium octenyl succinate starch, add water and mix, stir for 20 min, and let stand for 2 h to obtain mixture A;

[0062] (3) Mix and grind the separately weighed calcium hydroxide and gypsum to obtain mixture B; mixture A and mixture B together constitute the crushed stone soil solidifying agent of the present invention.

[0063] Example 3

[0064] The crushed stone soil solidifying agent of this example is composed of mixture A and mixture B; mixture A includes the following raw materials in parts by weight: 8 parts of polyanionic cellulose, 3 parts of sodium octenyl succinate starch, and 1000 parts of water; mixture B includes the following raw materials in parts by weight: 1 part of calcium hydroxide and 5 parts of gypsum.

[0065] The preparation method of the crushed stone soil solidifying agent of this example includes the following steps:

[0066] (1) Weigh the raw materials: 8 kg of polyanionic cellulose, 3 kg of sodium octenyl succinate starch and 1000 kg of tap water, 1 kg of calcium hydroxide, and 5 kg of gypsum; the relative molecular weight of polyanionic cellulose is 1 million, and the molecular weight of sodium octenyl succinate starch is 902.93;

[0067] (2) Mix and grind the separately weighed polyanionic cellulose and sodium octenyl succinate starch, add water and mix, stir for 30 min, and let stand for 2 h to obtain mixture A;

[0068] (3) Mix the separately weighed calcium hydroxide and gypsum plaster by grinding to obtain mixture B; mixture A and mixture B together constitute the gravel soil solidifying agent of the present invention.

[0069] The greatest advantage of the solidifying agents for gravel soil prepared in Example 1, Example 2 and Example 3 is that they can establish good connection ability between gravel and soil particles and enhance the cementing ability between soil and stone; in addition, the solidifying agent can absorb carbon dioxide gas released from the soil and induce the formation of calcium carbonate precipitation, greatly improving the water stability and strength of gravel soil; it not only solves the current situation that gravel soil is vulnerable to erosion and soil-stone separation, but also greatly improves the strength and water stability of gravel soil.

[0070] When the gravel soil solidifying agent of the present invention is applied in soil solidification and improving the strength performance and water stability performance of gravel soil, the specific method is as follows:

[0071] (1) Add mixture A to the gravel soil to be solidified at 12% of the mass of the gravel soil to be solidified, stir and let stand for 24 h;

[0072] (2) Then add mixture B to the gravel soil to be solidified containing the polymer solution of mixture A at 9% of the mass of the gravel soil to be solidified.

[0073] Application test of the gravel soil solidifying agent of the present invention:

[0074] First, mix the prepared loess and gravel with different particle sizes at a mass ratio of 1:1 to obtain gravel soil; then add mixture A at 12% of the mass of the gravel soil to the gravel soil, stir and let stand for 24 hours; finally, add mixture B at 9% of the mass of the gravel soil and prepare a specimen with a dry density of 1.8 g / cm 3 and cure for a period of time for testing.

[0075] 1. Water stability test

[0076] Reinforce the specimen with the mixtures A and B prepared in Example 1, completely immerse the specimen in water, and measure that the complete disintegration time of the specimen is 3 min. The complete disintegration time of the specimen cured with the solidifying agent prepared in Example 2 is 50 min, while the specimen reinforced with the solidifying agent prepared in Example 3 can exist intact in water for more than 170 min. Taking the specimen control group without adding any solidifying agent, it is measured that the specimen is completely damaged within 1.5 min, as shown in Figure 1 shown.

[0077] 2. Unconfined compressive strength test

[0078] The gravelly soil was reinforced with the solidifying agents prepared in Example 1, Example 2, and Example 3, and the unconfined compressive strengths of the specimens were measured to be 219.17 kPa, 272.17 kPa, and 563.67 kPa, respectively. The unconfined compressive strength of the soil without the addition of the solidifying agent was 123.77 kPa. The strength of the soil reinforced in Example 3 increased by 355.42% compared to the soil without the addition of the solidifying agent. See Figure 2 , Figure 2 which is the graph of the unconfined compressive test data for Example 1 - 3 and the control group. It can be seen that the solidifying agent of the present invention can significantly improve the strength of the loose gravelly soil. This curing agent can make the fine particles inside the soil more tightly cemented, thus significantly improving the soil strength.

[0079] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A solidifying agent for crushed stone soil, characterized in that, It is composed of mixture A and mixture B; The mixture A includes the following raw materials in parts by weight: 2 - 8 parts of polyanionic cellulose, 3 parts of sodium octenyl succinate starch, and 1000 parts of water; the relative molecular weight of the polyanionic cellulose is 1 million; The mixture B includes the following raw materials in parts by weight: 1 - 5 parts of calcium hydroxide, 1 - 5 parts of plaster of Paris; Among them, the dosage of the mixture A in the crushed stone soil solidifying agent is 12% of the mass of the crushed stone soil to be solidified, and the dosage of the mixture B is 9% of the mass of the crushed stone soil to be solidified.

2. A preparation method of a gravel soil solidifying agent, characterized in that, It includes the following steps: Mix and grind 2 - 8 parts of polyanionic cellulose and 3 parts of sodium octenyl succinate starch, add 1000 parts of water and mix. After stirring and standing, mixture A is obtained; among them, the relative molecular weight of the polyanionic cellulose is 1 million, and the time for stirring and standing is: stirring for 15 - 30 minutes and standing for 1.5 hours; Mix and grind 1 - 5 parts of calcium hydroxide and 1 - 5 parts of plaster of Paris to obtain mixture B; All raw materials are in parts by weight; The dosage of the mixture A in the crushed stone soil solidifying agent is 12% of the mass of the crushed stone soil to be solidified, and the dosage of the mixture B is 9% of the mass of the crushed stone soil to be solidified.

3. A method for using a solidifying agent for crushed stone soil, characterized in that The crushed stone soil solidifying agent is the crushed stone soil solidifying agent described in claim 1 or the crushed stone soil solidifying agent prepared by the preparation method described in claim 2; Add the mixture A to the crushed stone soil to be solidified at 12% of the mass of the crushed stone soil to be solidified, stir and stand; Then add mixture B to the crushed stone soil to be solidified containing the polymer solution of mixture A at 9% of the mass of the crushed stone soil to be solidified.

4. The method for using the gravel soil solidifying agent according to claim 3, characterized in that, The standing time is 12 - 24h.

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