A composite sandy soil solidifying agent and its application method

Abstract

The present invention discloses a composite sandy soil curing agent and its application method. This solution consists of component A and component B; component A is a liquid organic curing material, and component B is a solid inorganic curing material. In 100 parts of the composite curing agent, component A accounts for 70 parts and component B accounts for 30 parts. During application, the liquid component A in the composite sandy soil curing agent is diluted with water and then sprayed onto the subgrade clay; at the same time, the solid component B is fully mixed with cement and used along with the cement. The composite curing agent provided by the present invention can greatly improve the unconfined compressive strength of sandy soil under the condition of lower dosage, ensuring the project quality.

Description

Technical Field

[0001] The present invention relates to a composition, and particularly to a curing agent for sandy soil. Background Art

[0002] Sandy soil is a basic soil widely distributed in North China. It is mainly composed of particles with a size of 0.075 - 2 mm, has no plasticity, no cohesion between particles, and is loose in texture. When using sandy soil as the subgrade for highways and railways, due to the lack of cohesion between sandy soil particles, the existing solutions mainly adopt the method of "cement stabilized soil", that is, adding a certain amount of cement to the sandy soil to improve the unconfined compressive strength of the subgrade soil.

[0003] However, in the conventional "cement stabilized soil" method, the cohesion of sandy soil is mainly provided by the cementing ability of cement itself. However, since there is no cohesion between sandy soil particles, the treatment effect of cement soil only depends on the performance of cement, and the effect is poor. Therefore, the existing "cement stabilized soil" method has a poor effect on solidifying sandy soil, and the unconfined compressive strength is generally low, which has certain engineering hidden dangers. Summary of the Invention

[0004] Aiming at the problems of poor solidification effect and generally low unconfined compressive strength of the curing agent used when constructing the highway subgrade based on sandy soil, the purpose of the present invention is to provide a composite sandy soil curing agent; on this basis, the present invention further provides an application method of the composite sandy soil curing agent; accordingly, it can solidify the base soil and the strength increases rapidly, effectively overcoming the problems existing in the prior art.

[0005] In order to achieve the above purpose, the composite sandy soil curing agent provided by the present invention is composed of component A and component B; component A is a liquid organic curing material, and component B is a solid inorganic curing material. In 100 parts of the composite curing agent, component A accounts for 70 parts and component B accounts for 30 parts.

[0006] In some examples of the present invention, component A is composed of the following components by weight:

[0007]

[0008]

[0009] In some examples of the present invention, hydroxypropyl methylcellulose with a viscosity of 100000 mPa·s is used in component A.

[0010] In some examples of the present invention, component B is composed of the following components by weight:

[0011] Calcium chloride 14 - 16 parts;

[0012] 14 - 16 parts of sodium sulfate.

[0013] To achieve the above object, the application method of the composite sandy soil solidifying agent provided by the present invention is as follows: After diluting the liquid A component in the composite sandy soil solidifying agent with water, it is sprayed onto the subgrade clay; at the same time, the solid B component in the composite sandy soil solidifying agent is fully mixed with cement and used together with the cement.

[0014] In some examples of the present invention, the application method includes the following steps:

[0015] (1) Thoroughly sun-dry the subgrade sandy soil to be solidified.

[0016] (2) Take cement and the composite solidifying agent, and the dosage of the composite solidifying agent is 5% - 15% of the cement dosage;

[0017] (3) After fully mixing the B component in the composite solidifying agent with cement, evenly spread it on the clay to be solidified and thoroughly stir until the clay is fully mixed with the cement and the B component;

[0018] (4) After diluting the solidifying agent A component in the composite solidifying agent with water, spray it onto the subgrade clay.

[0019] (5) Thoroughly mix the subgrade soil, cement, and solidifying agent;

[0020] (6) Use a roller to roll the loose-laid clay to the designed thickness.

[0021] In some examples of the present invention, the water consumption in step (4) is determined according to the optimum moisture content of the soil.

[0022] The composite sandy soil solidifying agent solution provided by the present invention can greatly improve the unconfined compressive strength of sandy soil under the condition of low dosage, ensuring the project quality; in specific applications, it can solidify the subgrade soil of highways and railways, with fast strength growth and reliable quality; and can quickly treat shallow soft soil; it has a wide range of application scenarios.

[0023] The composite sandy soil solidifying agent solution provided by the present invention is different from the conventional "cement stabilized soil" method and also different from the existing traditional solidifying method of "epoxy resin + solidifying agent". It innovatively uses a variety of materials to construct a three-dimensional solidifying network in the sandy soil, improving the soil consolidation performance and density. In the composite sandy soil solidifying agent solution, hydroxypropyl methyl cellulose ether in component A provides a highly viscous film structure and network structure between soil and cement, cement and cement, and soil and soil in the solidified soil. At the same time, EP epoxy resin modified by γ-aminopropyltriethoxysilane strengthens the cohesion between cellulose ether, soil, and cement. Matched with it, calcium chloride in component B provides calcium ions for cement hydration, accelerating the overall cement hydration process. Sodium sulfate in component B accelerates the hydration reaction of C3A in cement, accelerating the early hydration rate of cement. Calcium chloride and sodium sulfate are equivalent to anti-seepage agents and early strength agents, improving the filling ability of cement for micro-cracks in sandy soil. The main function of component A is to improve the interfacial viscosity between soil particles and cement particles, and the main function of component B is to increase the cement hydration rate and improve the filling ability of cement for internal micro-cracks in sandy soil.

[0024] When the composite sandy soil solidifying agent solution is actually applied, it also has the advantages of low cost and good effect. Detailed implementation mode

[0025] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific examples.

[0026] After in-depth research on the characteristics of sandy soil and the problems of poor solidifying effect and low unconfined compressive strength when sandy soil is used as the highway base, the inventor of the present invention provides a composite sandy soil solidifying agent, which can greatly improve the unconfined compressive strength of sandy soil under the condition of low dosage, ensuring the project quality.

[0027] Therefore, the composite sandy soil solidifying agent is composed of the following two parts: component A and component B. Component A is a liquid organic solidifying material, and component B is a solid inorganic solidifying material; in 100 parts of the composite solidifying agent, component A accounts for 70 parts and component B accounts for 30 parts.

[0028] In the composite sandy soil solidifying agent, organic synergistic action between component A and component B is required to improve the solidifying effect on sandy soil and the unconfined compressive strength.

[0029] Component A in the composite sandy soil solidifying agent improves the interfacial viscosity between soil particles and cement particles; acting in cooperation with it, component B is used to increase the cement hydration rate and improve the filling ability of cement for internal micro-cracks in sandy soil.

[0030] On this basis, in order to effectively target the solidification effect and unconfined compressive strength of sandy soil, the dosage ratio of component A to component B in this composite sandy soil solidifying agent is A:B = 7:3. This can ensure the balanced improvement of the interfacial viscosity of sandy soil and the cement filling ability. If the dosage of component B is too large, it is easy to occur that the early hydration of cement is too fast and the strength growth of subgrade soil is slow in the later stage; if the dosage of component B is too small, it will affect the solidification effect of sandy soil and the unconfined compressive strength.

[0031] Furthermore, for component A and component B in this composite sandy soil solidifying agent, the two need to be used in combination according to the above ratio to achieve the best effect. Through a large number of experiments, it is determined that if component A is used alone or component B is used alone, the above effects cannot be achieved. Specifically, if component A is used alone, the dosage in this scheme needs to be increased by about 10 times to achieve the effect, which is costly and not practical; furthermore, if component B is used alone, if the effect of the present invention is achieved, it will have an adverse impact on the later strength development of the solidified soil.

[0032] On this basis, the present invention further gives the specific synergistic formula of component A and component B.

[0033] For component A in this composite sandy soil solidifying agent, it is composed of the following components by weight:

[0034]

[0035] In this component A, deionized water is used to adjust the concentration and viscosity of component A. The dosage of 64 - 66 parts by weight can make the concentration and viscosity of component A reach the best. If the dosage is too large, the concentration is low and the effect is poor; if the dosage is too low, the viscosity is high, the dispersion is difficult, and it cannot be used.

[0036] In this component A, hydroxypropyl methylcellulose ether provides a highly viscous film structure and network structure between soil and cement, cement and cement, and soil and soil in the solidified soil.

[0037] Preferably, the hydroxypropyl methylcellulose in this scheme is of experimental purity and has a viscosity of 100000 mPa·s.

[0038] In this component A, hydroxypropyl methylcellulose ether mainly affects the concentration and viscosity of component A. Compared with the ratio used in this scheme, if the dosage is too small, the concentration is low and the effect is poor; if the dosage is too high, the viscosity is high, the dispersion is difficult, and it cannot be used.

[0039] In this component A, γ-aminopropyltriethoxysilane and EP epoxy resin act synergistically for epoxy resin modification.

[0040] Preferably, the γ-aminopropyltriethoxysilane in this solution is of experimental purity, and a good modification effect can be achieved.

[0041] The dosage of γ-aminopropyltriethoxysilane in this Component A is coordinated with the dosage of EP epoxy resin in the solution. Compared with the ratio used in this solution, if it is too low, the modification effect is poor; if it is too high, the cost is high.

[0042] In this Component A, EP epoxy resin is used to cooperate with γ-aminopropyltriethoxysilane to strengthen the cohesion between cellulose ether, soil and cement based on the EP epoxy resin modified by γ-aminopropyltriethoxysilane.

[0043] Preferably, the EP epoxy resin in this solution is of type E44.

[0044] In this Component A, regarding the dosage of EP epoxy resin, compared with the ratio used in this solution, if the dosage is too small, the concentration is low and the effect becomes poor; if the dosage is too high, the viscosity is high, dispersion is difficult and it cannot be used.

[0045] Based on Component A composed of the above, Component B that cooperates with it is composed of the following components in parts by weight:

[0046] Calcium chloride: 14 - 16 parts;

[0047] Sodium sulfate: 14 - 16 parts.

[0048] In this Component B, calcium chloride is used to provide calcium ions for cement hydration and accelerate the overall cement hydration process.

[0049] Preferably, the calcium chloride in this solution is of analytical purity.

[0050] The dosage of calcium chloride in this Component B needs to be adapted to the dosage of sodium sulfate and the cement dosage. Compared with the ratio used in this solution, if the dosage of calcium chloride is too small, the ability to promote cement hydration is poor and the effect is affected; if the dosage of calcium chloride is too high, the cement hydrates too fast, resulting in insufficient mixing of cement and soil and affecting the effect.

[0051] In this Component B, sodium sulfate is used to accelerate the hydration reaction of C3A (tricalcium aluminate) in cement and accelerate the early cement hydration rate.

[0052] Preferably, the sodium sulfate in this solution is of analytical purity.

[0053] The dosage of sodium sulfate in this Component B needs to be adapted to the dosage of calcium chloride and the cement dosage. Compared with the ratio used in this solution, if the dosage of sodium sulfate is too small, the ability to promote C3A hydration of cement is poor and the effect is affected; if the dosage of sodium sulfate is too high, the late strength of cement is reduced, affecting the construction quality.

[0054] In the composite sandy soil solidifying agent thus formed, the liquid A component synergistically acts with high-viscosity cellulose and epoxy resin to improve the consolidation performance and water stability of the sandy soil. At the same time, the cellulose network provides a development synapse for the hydration products of cement, enhancing the contact ability between the cementitious material and the sandy soil. Moreover, the components in the solid B component interact with each other systematically to enhance the impermeability of the concrete, and can effectively fill the internal gaps in the solidified soil, improving the density of the solidified soil.

[0055] For the composite sandy soil solidifying agent provided by the present invention, a corresponding preparation scheme is further given.

[0056] This preparation scheme is based on the above A component formula and includes deionized water, hydroxypropyl methylcellulose, γ-aminopropyltriethoxysilane, and EP epoxy resin.

[0057] At the same time, the preparation equipment used includes a high-speed stirrer.

[0058] Here, under the condition that the test temperature is 25 ± 5 °C, taking the preparation of 70 parts of the A component as an example, the preparation process of the composite sandy soil solidifying agent given by the present invention is illustrated.

[0059] First, prepare 70 parts of the A component:

[0060] (1) Take 64 - 66 parts of deionized water, add it to the preparation stirring container, and stir at a speed of 180 - 220 r / min.

[0061] (2) Take 0.64 - 0.66 parts of hydroxypropyl methylcellulose ether, and slowly add it to the preparation stirring container. Here, it is preferably added evenly within 1 min. At the same time, the stirring speed increases with the addition of hydroxypropyl methylcellulose. When the hydroxypropyl methylcellulose is completely added, the stirring speed should be increased to 1100 - 1300 r / min. In this way, the hydroxypropyl methylcellulose ether is evenly dispersed in the deionized water.

[0062] (3) Stir for 45 - 50 min until the hydroxypropyl methylcellulose ether is completely dissolved.

[0063] (4) Take 1.94 - 1.96 parts of γ-aminopropyltriethoxysilane and add it to the preparation stirring container.

[0064] (5) Stir for 30 - 35 min until the liquid in the container is turbid and uniform, so that γ-aminopropyltriethoxysilane is evenly dispersed in the cellulose ether aqueous solution.

[0065] (6) Take 2.3 - 2.5 parts of EP epoxy resin and slowly add it to the preparation stirring container. Here, it is preferably added evenly within 1 min for the EP epoxy resin.

[0066] (7) Increase the rotational speed to 1800 - 2000 r / min and stir for 120 - 130 min until the liquid in the container completely turns into a milky white liquid.

[0067] (8) Obtain the product of component A of the curing agent.

[0068] In this way, based on the above steps (1) - (8), they are sequentially coordinated in order to complete the preparation of component A by first dispersing cellulose ether, then dispersing γ - aminopropyltriethoxysilane, and finally dispersing epoxy resin, effectively avoiding the problem that other substances will be difficult to disperse if epoxy resin is dispersed first.

[0069] Next, prepare 30 parts of component B: Component B is a solid material, directly composed of 14 - 16 parts of calcium chloride and 14 - 16 parts of sodium sulfate.

[0070] When the composite sandy soil curing agent prepared based on the formula and preparation method given in the present invention is specifically applied, it can greatly improve the unconfined compressive strength of sandy soil under the condition of low dosage, ensuring the project quality. In this regard, for the composite sandy soil curing agent provided by the present invention, a corresponding application plan is further given. The corresponding application process is as follows:

[0071] The composite sandy soil curing agent prepared based on the formula and preparation method given in the present invention specifically includes component A and component B. Among them, component A is a liquid component, which is diluted with water during application and then sprayed onto the subgrade clay for use; correspondingly, component B is a solid component, which is used to be fully mixed with cement and then used together with cement.

[0072] Accordingly, the specific application process is as follows:

[0073] (1) Thoroughly sun-dry the subgrade sandy soil to be cured, so as to make the soil fluffy and easy to mix with cement and the curing agent.

[0074] (2) Take P.O 32.5 cement, and the cement dosage is 3 - 5% of the mass of the clay.

[0075] (3) Take the composite sandy soil curing agent, and the curing agent dosage is about 5% - 15% of the cement dosage. In this way, the strength of the cured soil can reach between 120% - 220% of the strength of the cement soil. Taking the curing agent dosage of 15% of the cement dosage as an example, the dosage of component A is 10.5% of the cement, and the dosage of component B is 4.5% of the cement.

[0076] (4) After fully mixing component B with cement, evenly spread it on the clay to be cured and thoroughly stir until the clay is fully mixed with cement and component B.

[0077] (5) After diluting component A of the curing agent with water, spray it onto the subgrade clay.

[0078] In this step, the water consumption is determined according to the optimum moisture content of the soil. Water consumption = mass of clay × (optimum moisture content - current moisture content). Such an amount can make the soil reach the optimum moisture content after adding water, thus achieving the best compaction effect.

[0079] (6) Use a soil stabilizer to fully mix the subgrade soil, cement, and curing agent.

[0080] (7) Use a roller to roll the loose-laid clay to the designed thickness.

[0081] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions noted in the following embodiments are generally determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0082] Unless otherwise defined or stated, all professional and scientific terms used herein have the same meaning as those familiar to persons skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the method of the present invention.

[0083] Example 1.

[0084] In a highway construction section, the designed thickness of the subgrade clay construction layer is 30 cm, and the loose-laid thickness is 39 cm. The mass of the clay to be treated in this layer is 10 t, the moisture content is 7%, and the optimum moisture content is 12% through experimental detection.

[0085] Use the composite sandy soil curing agent given by the present invention to cure the clay subgrade: Spread 200 kg of cement and 9 kg of component B of the curing agent on the clay layer, and use a soil stabilizer to fully mix the cement and soil. Use 21 kg of component A of the curing agent and 500 kg of water, fully mix and dilute. Spray it onto the subgrade clay. Use a soil stabilizer to fully mix the subgrade soil, cement, and curing agent. Use a roller to roll the loose-laid clay to the designed thickness.

[0086] Example 2.

[0087] In a railway construction section, the designed thickness of the subgrade clay construction layer is 25 cm, and the loose-laid thickness is 35 cm. The mass of the clay to be treated in this layer is 20 t, the moisture content is 8%, and the optimum moisture content is 13% through experimental detection.

[0088] The composite sandy soil solidifying agent provided by the present invention is used to solidify the clay subgrade: 400 kg of cement and 18 kg of component B of the solidifying agent are spread on the clay layer, and a soil stabilizer mixer is used to fully mix the cement and the soil. 42 kg of component B of the solidifying agent and 1000 kg of water are fully mixed and diluted. Then it is sprayed onto the subgrade clay. A soil stabilizer mixer is used to fully mix the subgrade soil, cement and solidifying agent. A roller is used to roll the loose-laid clay to the designed thickness.

[0089] Example 3.

[0090] For a shallow soft soil foundation of a certain highway, the mass of the clay to be treated is about 15 t, and the water content is 17%. After experimental testing, the optimum water content of this clay is 12%.

[0091] The composite sandy soil solidifying agent provided by the present invention is used to solidify the clay subgrade: The soft soil foundation is dewatered by pumping 650 kg of water. 300 kg of cement and 13.5 kg of component B of the solidifying agent are spread on the soft soil layer. 31.5 kg of component A of the solidifying agent and 100 kg of water are fully mixed and diluted. Then it is sprayed onto the clay. A soil stabilizer mixer is used to fully mix the subgrade soil, cement and solidifying agent. A roller is used to roll until the foundation does not sink under the static pressure of the roller.

[0092] Comparative Example 1.

[0093] For a part of the clay subgrade of the railway construction section targeted in Example 2, 5% cement is used for soil treatment.

[0094] Comparative Example 2.

[0095] For a part of the clay subgrade of the railway construction section targeted in Example 2, 10% cement is used for soil treatment.

[0096] Case 4

[0097] Based on the results of the treatment of the sandy soil foundation of the same railway project targeted in Example 2, Comparative Example 1 and Comparative Example 2, the 7-day compressive strength is actually measured 6 times respectively. The specific actual measurement results are shown in Table 1.

[0098] Table 1 Results of the solidification treatment of the foundation soil of a certain railway project

[0099]

[0100] As shown in Table 1, Condition 1 is the result of soil treatment with 5% cement, Condition 2 is the result of soil treatment with 10% cement, and Condition 3 is the result of soil treatment with 5% cement and the composite solidifying agent provided by the present invention.

[0101] Result shows that after using the composite sandy soil solidifying agent provided by the present invention, with the same amount of cement used, the strength is increased by 121%. Compared with the 10% cement solidified soil, the strength is increased by up to 36%, achieving an unexpected technical effect. This solidifying agent can achieve the purpose of reducing the amount of cement used and improving the unconfined strength of the sandy soil foundation.

[0102] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. Application method of a composite sandy soil solidifying agent Characterized in that It includes the following steps: (1) Thoroughly sun-dry the subgrade sandy soil to be solidified; (2) Take cement and the composite solidifying agent. The dosage of cement is 3%-5% of the mass of the sandy soil, and the dosage of the composite solidifying agent is 5%-15% of the cement dosage; (3) After fully mixing component B in the composite solidifying agent with cement, evenly spread it on the sandy soil to be solidified, and thoroughly stir until the sandy soil is fully mixed with cement and component B; (4) Dilute component A of the composite solidifying agent with water and spray it onto the subgrade sandy soil; (5) Thoroughly mix the subgrade sandy soil, cement, and solidifying agent; (6) Use a road roller to roll the loose-laid sandy soil to the designed thickness; Wherein The composite sandy soil solidifying agent is composed of component A and component B; Component A is a liquid organic solidifying material, and component B is a solid inorganic solidifying material. In 100 parts of the composite solidifying agent, component A accounts for 70 parts and component B accounts for 30 parts; Component A is composed of the following components in parts by weight: Deionized water 64-66 parts; Hydroxypropyl methylcellulose ether 0.64-0.66 parts; γ-Aminopropyltriethoxysilane 1.94-1.96 parts; EP epoxy resin 2.3-2.5 parts; Component B is composed of the following components in parts by weight: Calcium chloride 14-16 parts; Sodium sulfate 14-16 parts.

2. The application method of the composite sandy soil solidifying agent according to claim 1 Characterized in that Hydroxypropyl methylcellulose with a viscosity of 100000 mPa·s is used in component A.

3. The application method of the composite sandy soil solidifying agent according to claim 1 Characterized in that The water consumption in step (4) is determined according to the optimum moisture content of the soil.

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