Fluidized solidified soil for reinforcing embankment and reinforcing method thereof

Abstract

The invention provides flow-state solidified soil for embankment reinforcement and a reinforcement method of the flow-state solidified soil, and belongs to the technical field of embankment reinforcement. The flow-state solidified soil for reinforcing the embankment comprises a soil material, cement, a microbial agent, a nutrient source, an additive and water, wherein the weight percentage of the soil material is 55%-68%, the weight percentage of the cement is 10%-16%, the weight percentage of the microbial agent is 1%-2%, the weight percentage of the nutrient source is 1%-2%, the weight percentage of the additive is 0-1.0%, and the weight percentage of the water is 20%-25%. The flow-state solidified soil provided by the invention has high mechanical property, high stability and corrosion resistance, can realize ecological solidification of an embankment soil body, remarkably improves the mechanical property and stability of the embankment soil body, and effectively controls the problems of roadbed corrosion and differential settlement.

Description

Technical Field

[0001] At least one embodiment of the present invention relates to a embankment reinforcement material, and more particularly to a fluidized solidified soil for embankment reinforcement and a reinforcement method thereof. Background Art

[0002] With the acceleration of urbanization, various types of backfill projects are increasing, including the filling of underground cavities and construction pits, as well as the backfilling of embankment widening projects. Especially in the process of embankment widening, the stability of the junction of the new and old embankments and the control of differential settlement have become key technical problems. Traditional reinforcement methods often face problems such as environmental pollution, high cost, and insufficient long-term stability. In addition, the construction process is complicated, the quality is unstable, and it is easy to cause roadbed subsidence. In addition, multiple rolling is required during construction, and the construction period is long. In addition, the cementitious materials in the backfill materials are mostly cement-based, which not only consumes a lot of energy and natural resources, but also releases a lot of carbon dioxide, significantly increases greenhouse gas emissions, and is not conducive to achieving sustainable development and effective use of resources; and it also takes a long time for consolidation and maintenance, and the construction period is long, which seriously affects the restoration of the normal traffic function of the widened road. Therefore, traditional embankment filling materials (also known as embankment reinforcement materials) have a serious negative impact on environmental and resource protection. Summary of the invention

[0003] In view of this, in order to at least partially solve the above-mentioned technical problems, the present invention provides a fluidized solidified soil for embankment reinforcement and a reinforcement method thereof.

[0004] According to an embodiment of one aspect of the present invention, there is provided a fluidized solidified soil for embankment reinforcement, comprising soil material, cement, microbial agent, nutrient source, admixture and water; wherein the weight percentage of the soil material is 55% to 68%, the weight percentage of the cement is 10% to 16%, the weight percentage of the microbial agent is 1% to 2%, the weight percentage of the nutrient source is 1% to 2%, the weight percentage of the admixture is 0 to 1.0%, and the weight percentage of water is 20% to 25%.

[0005] According to another embodiment of the present invention, there is provided a method for reinforcing an embankment using the fluidized solidified soil, comprising:

[0006] A retaining wall is installed on the outer side of the embankment to be widened to form a casting space between the embankment to be widened and the retaining wall; the fluidized solidified soil is poured into the casting space in layers and compacted to form a fluidized solidified soil layer; and the fluidized solidified soil layer formed in the casting space is covered with a moisture retaining material to maintain the fluidized solidified soil layer.

[0007] According to the fluidized solidified soil used for embankment reinforcement provided by the above-mentioned embodiment of the present invention, microorganisms are used to induce the precipitation of silicates and calcium carbonate to improve the properties of the fluidized solidified soil, so that the fluidized solidified soil has high mechanical properties, high stability and corrosion resistance, can achieve ecological solidification of the embankment soil, significantly improve the mechanical properties and stability of the embankment soil, and effectively control roadbed corrosion and differential settlement problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0009] Figure 1 A schematic diagram of using fluidized solidified soil provided in an embodiment of the present invention for embankment reinforcement;

[0010] Figure 2 A schematic flow chart of a reinforcement method for embankment reinforcement using fluidized solidified soil provided in an embodiment of the present invention;

[0011] Description of reference numerals:

[0012] 1- Foundation;

[0013] 2-Embankment to be widened;

[0014] 3- Retaining wall;

[0015] 4- Fluidized solidified soil layer. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. However, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the invention thorough and complete and fully convey the scope of the present invention to those skilled in the art. In the accompanying drawings, for clarity, the sizes and relative sizes of layers and regions may be exaggerated, and the same reference numerals throughout represent the same elements.

[0017] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0018] Fluid filling materials are formed into a filling material with certain fluidity and mechanical properties by using engineering soil, environmentally friendly composite gelling agent and other reinforcing agents. It has the characteristics of self-compacting, rapid construction, wide application range and environmental friendliness. It can be used in embankment widening and reinforcement projects of various environments and grades. Microbial metabolism induces the precipitation of calcium carbonate and silicate in the soil, which can significantly enhance the shear strength, bearing capacity and long-term stability of the widened soil. The sediment produced by microbial metabolism contains a large amount of carbon, which can effectively seal carbon in the soil and reduce carbon emissions. In addition, the generated consolidation layer can effectively reduce the penetration of water or pollutants. Therefore, the combination of microbial metabolism-induced soil precipitation technology and fluid filling materials provides an innovative solution for embankment widening.

[0019] In view of this, it is urgent to develop an enhanced fluidized solidified soil embankment reinforcement material based on biological induced sedimentation technology. The present invention provides a fluidized solidified soil used for embankment reinforcement. The material can give full play to the advantages of fluidized filling materials and biological induced sedimentation technology, significantly improve the mechanical properties and stability of the fluidized solidified soil filled embankment, and have good corrosion resistance; the embankment filled with the enhanced fluidized solidified soil reinforcement material has a small settlement, which significantly reduces the differential settlement with the existing embankment and ensures the integrity of the road surface; and the number of rolling times required during the construction process is less, which significantly improves the construction efficiency and has significant social and economic benefits. In addition, it is also necessary to determine a suitable construction method for the material in the embankment widening project.

[0020] According to an exemplary embodiment of the present invention, the present invention provides a fluidized solidified soil for embankment reinforcement, the fluidized solidified soil comprising soil, cement, microbial agent, nutrient source, admixture and water; wherein the weight percentage of the soil is 55% to 68%, the weight percentage of the cement is 10% to 16%, the weight percentage of the microbial agent is 1% to 2%, the weight percentage of the nutrient source is 1% to 2%, the weight percentage of the admixture is 0 to 1.0%, and the weight percentage of water is 20% to 25%.

[0021] It should be noted that the water in the fluid solidified soil only needs to be able to ensure the fluidity and constructability of the fluid solidified soil.

[0022] In some embodiments, the soil material is clay and / or silt having cohesiveness and plasticity.

[0023] In some embodiments, the cement is PO42.5R Portland cement which has a faster setting and hardening speed.

[0024] In some embodiments, the nutrient source includes urea (CO(NH2)2), potassium dihydrogen phosphate (KH2PO4) and sodium silicate (Na2SiO3), wherein urea is used as the main carbon source and potassium dihydrogen phosphate is used as the phosphorus source; wherein the molar ratio of urea to sodium silicate is 0.9-1.1, and the molar ratio may be, for example, 0.9, 1.0, 1.1, but is not limited to the values ​​cited. By controlling the molar ratio of urea to sodium silicate to 0.9-1.1, the growth of microorganisms in the fluidized solidified soil can be maintained, and the excessive inhibition of microorganism growth by a single element can be avoided, which is beneficial to promoting the embankment reinforcement process and achieving the requirements of improving soil strength and stability.

[0025] In some embodiments, the molar ratio of urea to potassium dihydrogen phosphate is 1.0-2.0, and the molar ratio can be, for example, 1.0, 1.2, 1.5, 1.8, 2.0, but is not limited to the values ​​cited. By controlling the molar ratio of urea to potassium dihydrogen phosphate to 1.0-2.0, it is possible to avoid excessive differences in the content of urea and potassium dihydrogen phosphate that inhibit the growth of microorganisms, which is beneficial to promoting the embankment reinforcement process.

[0026] In some embodiments, the microbial agent includes Priesteria avorei, which can tolerate a salt concentration of 7% and can grow normally in an environment with a pH of 5.0 to 9.0. Priesteria avorei is an efficient silica-dissolving bacterium that can effectively induce silicate precipitation; and Priesteria avorei also has the function of dissolving phosphates, which can promote the improvement of soil aggregate stability in saline soil and stabilize the water-stable structure of soil aggregates.

[0027] According to an embodiment of the present invention, the enzyme in Priesteria axyriformis generates silicate precipitation and forms an anti-corrosion layer through reaction steps S01 to S03, specifically:

[0028] Step S01, Priestia aryabhattai produces urease;

[0029] In step S02, urea in the nutrient source reacts with water and decomposes under the action of urease, and the reaction formula is shown in formula (1):

[0030] (1);

[0031] In step S03, the ammonia and carbonate ions generated by decomposition react with silicate minerals in the fluidized solidified soil to generate silicate precipitation, as shown in formula (2):

[0032] (2);

[0033] The overall chemical reaction formula is shown below, where: For silicate precipitation, , including various forms of hydrated silicates, as shown in formula (3):

[0034] (3).

[0035] According to an embodiment of the present invention, urea in the nutrient source can achieve soil stabilization by hydrolyzing and calcifying into calcium carbonate. Specifically, calcium carbonate precipitates at the contact points and pore spaces between soil particles, thereby binding the particles together and filling the inter-particle gaps, improving soil properties, including increasing soil strength and stiffness and reducing permeability. The specific reaction of urea hydrolyzing and calcifying into calcium carbonate includes steps S10 to S40.

[0036] Step S10, urea is hydrolyzed to produce ammonia and carbamic acid, thereby increasing the pH value of the fluidized solidified soil, as shown in formula (4);

[0037] (4);

[0038] Step S20, carbamic acid is further hydrolyzed into ammonia and carbonic acid, as shown in formula (5);

[0039] (5);

[0040] In step S30, ammonia further reacts to generate ammonium ions, carbonate ions, and hydroxide ions, which further increases the pH value of the fluidized solidified soil, as shown in equations (6) and (7);

[0041] (6);

[0042] (7);

[0043] Step S40, when supersaturation is reached, the reaction between carbonate ions and calcium ions in the fluidized solidified soil mixture will lead to the precipitation of calcium carbonate, as shown in formula (8);

[0044] (8).

[0045] According to an embodiment of the present invention, the ratio of the mass of the microbial agent to the mass of the nutrient source is 0.9 to 1.1, for example, it can be 0.9, 1.0, 1.1, but it is not limited to the values ​​cited. By adjusting the ratio of the microbial agent to the nutrient source to 0.9 to 1.1, after a series of chemical reactions, calcium carbonate precipitation and silicate precipitation are generated and an anti-corrosion layer is formed, thereby realizing the ecological reinforcement of the embankment soil, significantly improving the mechanical properties and stability of the soil, effectively controlling the roadbed corrosion and differential settlement problems, and also having the advantages of environmental protection and simple construction. Specifically, calcium carbonate precipitation and silicate precipitation effectively fill the pores of the newly built embankment, reduce the settlement of the newly built embankment after it is put into use, and reduce the settlement difference with the original embankment, which can effectively control the differential settlement of the new and old embankments.

[0046] In some embodiments, the admixture includes a pH regulator, a stabilizer and a water-retaining agent; wherein the weight percentage of the pH regulator in the admixture is any value between 20% and 30%, for example, it can be 20%, 24%, 25%, 28%, 30%, but is not limited to the values ​​cited; the weight percentage of the stabilizer in the admixture is any value between 40% and 60%, for example, it can be 40%, 45%, 50%, 55%, 60%, but is not limited to the values ​​cited; the weight percentage of the water-retaining agent in the admixture is any value between 10% and 20%, for example, it can be 10%, 12%, 14%, 18%, 20%, but is not limited to the values ​​cited.

[0047] According to the embodiment of the present invention, the admixture is suitable for improving the physical and chemical environment of the fluidized solidified soil, ensuring the normal survival of the microbial agent and the smooth progress of the chemical reaction.

[0048] In some embodiments, the pH regulator is selected from one or more of calcium hydroxide (Ca(OH)2), sulfur (S) and aluminum sulfate (Al2(SO4)3), preferably calcium hydroxide (Ca(OH)2). Since Priesteria axotris can tolerate a salt concentration of 7% and can grow normally in an environment with a pH of 5.0-9.0, the pH regulator is used to adjust the pH of the fluidized solidified soil to 5.0-9.0, so that Priesteria axotris can grow normally.

[0049] In some embodiments, the stabilizer is selected from one or more of lime, fly ash and organic polymer, preferably fly ash.

[0050] In some embodiments, the water retaining agent is preferably carboxymethyl cellulose (CMC) or diatomaceous earth.

[0051] According to an embodiment of the present invention, the present invention provides a reinforcement material that meets the requirements of widening embankments and uses a specific microbial-induced silicate precipitation technology to improve the long-term corrosion resistance and stability of fluidized solidified soil. The fluidized solidified soil is prepared with engineering soil, microbial agents, nutrient sources, admixtures and construction water as raw materials, and the admixture is used to improve the working performance of the fluidized solidified soil. The pH regulator regulates the acid-base environment of the mixed system to promote the normal reproduction and survival of the microbial agents. The water retaining agent ensures the smooth progress of the precipitation reaction. The stabilizer improves the structure and physical properties of the soil, increases the compressive strength and stability of the embankment after filling, and utilizes Na2SiO3, Ca(OH)2 and CO(NH2)2 to react to generate calcium carbonate and silicate precipitation and form an anti-corrosion layer, so that the fluidized solidified soil used for embankment reinforcement has good working performance, mechanical properties, long-term corrosion resistance and stability.

[0052] The fluidized solidified soil provided by the present invention meets the relevant performance requirements of the "Technical Standard for Premixed Fluidized Solidified Soil Filling" (T / CECS1037-2022), the "Technical Standard for Premixed Fluidized Solidified Soil Engineering Application" (DBJ51 / T188-2022), and the "Technical Regulations for Premixed Fluidized Solidified Soil Filling" (DB1310 / T298-2023), and has significant social, economic and environmental benefits.

[0053] Figure 1 A schematic diagram of using fluidized solidified soil provided in an embodiment of the present invention for embankment reinforcement.

[0054] Figure 2 A schematic flow chart of a reinforcement method for embankment reinforcement using fluidized solidified soil provided in an embodiment of the present invention.

[0055] According to an exemplary embodiment of the present invention, the present invention provides a reinforcement method for embankment reinforcement using fluidized solidified soil, referring to Figure 1 , Figure 2 As shown, it includes operations S1 to S3.

[0056] In operation S1, a retaining wall is installed outside the embankment to be widened to form a casting space between the embankment to be widened and the retaining wall.

[0057] According to an embodiment of the present invention, before reinforcing the embankment to be widened, a geological and soil survey is conducted on the embankment to be widened, and the weight percentage of each component in the fluidized solidified soil is determined based on the geology and soil of the embankment to be widened.

[0058] In the embodiments of the present invention, the ratio of soil, cement and water is determined according to the required strength of the newly built embankment, the cohesiveness of the soil, the fluidity conditions of the fluidized solidified soil, etc.; the configuration ratio of the admixture is determined according to environmental factors, such as the acidity and alkalinity of the soil, the cement content, etc.; and the percentage of the microbial agent and the nutrient source is comprehensively determined in combination with the above-mentioned overall factors.

[0059] According to an embodiment of the present invention, before reinforcing the embankment to be widened, the water content of the embankment to be widened is adjusted to an optimal construction state.

[0060] In the embodiment of the present invention, the soil on site is tested by a standard compaction test to obtain a moisture content relationship curve, and the peak point is taken as the optimal moisture content.

[0061] When the water content is too low, there is a lack of lubrication between the particles in the soil, making compaction difficult. When the water content is moderate, water acts as a lubricant, allowing the soil particles to be arranged more closely, achieving the maximum dry density. When the water content is too high, the excess water will cause the pores to become larger, which in turn reduces the density.

[0062] According to an embodiment of the present invention, before adjusting the water content of the embankment to be widened, the soil in the area of ​​the embankment to be widened is loosened to remove stones and other impurities in the soil.

[0063] According to an embodiment of the present invention, referring to Figure 1 As shown, a retaining wall 3 is applied on at least one side of the embankment 2 to be widened to form a casting space between the foundation 1, the embankment 2 to be widened and the retaining wall 3. Among them, applying a retaining wall 3 on at least one side of the embankment 2 to be widened includes reinforcing the base before construction, tying steel bars, supporting formwork, pouring concrete according to the design plan, and removing the formwork and inspecting the quality of the retaining wall after curing for 7 days. The soil before and after the retaining wall is backfilled and compacted in layers according to the design requirements, and the thickness of each layer is generally not more than 30 cm. The soil layer behind the wall is backfilled to the same height as the original roadbed.

[0064] In some embodiments, the retaining wall 3 is a gravity retaining wall. The quality inspection of the retaining wall 3 shows that the unconfined compressive strength after curing for 7 days (7d unconfined compressive strength) reaches 21-25MPa.

[0065] Operation S2, pouring the fluidized solidified soil into the pouring space in layers and compacting it to form a fluidized solidified soil layer 4.

[0066] According to an embodiment of the present invention, preparing fluidized solidified soil includes preparing soil, cement, and water; preparing a nutrient source; preparing an admixture; preliminarily mixing the soil and cement with water, adding microbial agents, nutrient sources, and admixtures to the mixture in sequence, and evenly mixing to obtain fluidized solidified soil.

[0067] According to an embodiment of the present invention, preparing soil materials includes pre-treating the soil materials used for fluidized solidified soil to remove debris (plants, stones, etc.) therein.

[0068] According to an embodiment of the present invention, preparing the nutrient source includes fully mixing urea, potassium dihydrogen phosphate and sodium silicate according to a preset ratio to obtain the nutrient source.

[0069] According to an embodiment of the present invention, preparing the admixture includes fully mixing a pH regulator, a stabilizer, and a water retaining agent according to a preset ratio to obtain the admixture.

[0070] In some embodiments, the fluidized solidified soil is poured into the pouring space in layers, so that each layer of the poured fluidized solidified soil can be evenly filled in the pouring space. The thickness of each layer of the fluidized solidified soil during the pouring and compacting process of the fluidized solidified soil into the pouring space is less than or equal to 30 cm.

[0071] Operation S3, covering the fluidized solidified soil layer formed in the pouring space with a moisture retaining material to maintain the fluidized solidified soil layer.

[0072] According to an embodiment of the present invention, after the fluidized solidified soil layer is formed, a moisturizing material is covered on the fluidized solidified soil layer to maintain a suitable temperature of 25-30°C, promote microbial growth, ensure enzyme activity, accelerate the formation of silicate precipitation and form an anti-corrosion layer.

[0073] In some embodiments, the moisture retaining material comprises a geotextile or a plastic film.

[0074] In some embodiments, the curing time of the fluidized solidified soil may be, for example, 7 days.

[0075] According to an embodiment of the present invention, after the curing period, the reinforced embankment soil is tested for unconfined compressive strength, permeability, stability, corrosion resistance and other indicators.

[0076] According to an embodiment of the present invention, the unconfined compressive strength (7d unconfined compressive strength) of the fluidized solidified soil layer after curing for 7 days reaches 1.5MPa~2.0MPa.

[0077] According to an embodiment of the present invention, the fluidized solidified soil provided by the present invention is suitable for roadbed widening, reinforcement and filling projects in various complex areas such as saline soil areas, soft soil areas, earthquake-prone areas and heavy-load traffic sections; the fluidized solidified soil is also suitable for use in roadbed reinforcement and filling projects of various levels of roads such as expressways, first-class highways, and secondary highways.

[0078] According to the embodiments of the present invention, the mechanical properties and stability of fluidized solidified soil are significantly improved through microbial induced silicate precipitation technology.

[0079] According to the embodiments of the present invention, the fluidized solidified soil provided by the present invention can improve the stability of the embankment. Specifically, through the action of microorganisms, silicate precipitates form an enhanced bonding network inside the soil, so that the bonding between soil particles is tighter, and the unconfined compressive strength of the soil is significantly improved, which greatly enhances the stability and bearing capacity of the embankment, enabling it to better cope with various external forces and reduce the possibility of deformation and damage.

[0080] According to the embodiments of the present invention, the fluidized solidified soil provided by the present invention can control the differential settlement of new and old embankments. Specifically, calcium carbonate precipitation and silicate precipitation effectively fill the pores of the newly built embankment, thereby reducing the settlement of the newly built embankment after it is put into use, and reducing the settlement difference with the original embankment, thereby effectively controlling the differential settlement, which not only improves the flatness of the embankment, but also reduces the risk of pavement cracking and damage caused by settlement differences, thereby extending the service life of the pavement.

[0081] According to the embodiments of the present invention, the fluidized solidified soil provided by the present invention can improve the long-term stability of the embankment. Specifically, the silicate precipitate formed by microbial mineralization has excellent chemical and physical stability and can maintain its strength and stability during long-term use. This long-term stability enables the embankment to maintain high durability when facing harsh natural conditions (such as long-term rainwater erosion and temperature changes), and is suitable for use in high-load transportation facilities.

[0082] According to the embodiments of the present invention, the fluidized solidified soil provided by the present invention has the advantage of being environmentally friendly. Specifically, the technology uses microbial agents and biodegradable nutrient sources throughout the process, which not only effectively reduces the use of chemical materials, but also reduces environmental pollution. Compared with traditional soil reinforcement methods, the microbial induction method is more environmentally friendly and sustainable, which helps to reduce the negative impact of the project on the surrounding ecosystem.

[0083] According to the embodiments of the present invention, the fluidized solidified soil provided by the present invention has anti-corrosion performance. Specifically, through the reinforcement of silicate precipitation, the anti-corrosion performance of the embankment is significantly improved. The silicate precipitation forms a protective layer in the soil, which can effectively prevent the invasion of corrosive substances and delay the deterioration process of the soil. This not only prolongs the service life of the embankment, but also reduces the cost of future maintenance and repair.

[0084] The following schematically illustrates the designed fluidized solidified soil for embankment reinforcement and the reinforcement method thereof. It should be noted that the exemplary description is only a specific embodiment of the present invention and cannot limit the protection scope of the present invention.

[0085] Example 1

[0086] Prepare fluidized solidified soil. The fluidized solidified soil includes soil material, cement, microbial agent, nutrient source, admixture and water; wherein, the weight percentage of soil material is 60.4%, the weight percentage of cement is 13.3%, the weight percentage of microbial agent is 2%, the weight percentage of nutrient source is 2%, the weight percentage of admixture is 1%, and the weight percentage of water is 21.3%. The soil material is clay with good cohesion and plasticity. The nutrient source includes urea, potassium dihydrogen phosphate and sodium silicate; wherein, the molar ratio of urea to sodium silicate is 1:1; the molar ratio of urea to potassium dihydrogen phosphate is 1:1.4. The stabilizer is lime; the water retaining agent is diatomaceous earth; the weight percentage of pH adjuster in the admixture is 30%, the weight percentage of stabilizer is 50%, and the weight percentage of water retaining agent is 20%, as shown in Table 1.

[0087] Table 1

[0088]

[0089] The fluidized solidified soil is poured in layers into the pouring space formed by the embankment to be widened and the retaining wall and compacted to form a fluidized solidified soil layer.

[0090] The fluidized solidified soil layer formed in the pouring space is covered with a moisture retaining material to maintain the fluidized solidified soil layer.

[0091] After the curing period, the fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results are: 7d unconfined compressive strength 1.88MPa, fluidity 267.5mm, water loss rate 13.8%; this can show that the fluidized solidified soil layer formed after the fluidized solidified soil of Example 1 is applied to embankment reinforcement has high strength, low water loss rate, and suitable fluidity, and can achieve the effect of rapid embankment reinforcement.

[0092] It should be noted that fluidity can reflect the fluidity and constructability of fluidized solidified soil. If the fluidity is too low, the fluidized solidified soil mixture will have poor fluidity, inconvenient construction, and difficult self-flow, filling and compaction. If the fluidity is too high, it may cause the solidified soil to stratify and seep water, affecting the later strength and uniformity.

[0093] The water loss rate can reflect the durability of fluidized solidified soil. If the water loss rate is too high, the porosity in the solidified soil will increase, the internal microstructure will become loose, and the strength will decrease, thus reducing the durability. If the water loss rate is too low, the cement will not be hydrated enough, the strength development will be hindered, and the later strength will be low, which will affect the durability of fluidized solidified soil.

[0094] Example 2

[0095] The preparation process of fluidized solidified soil and the process of applying it to embankment reinforcement are the same as those in Example 1, except that the weight percentage of soil in the fluidized solidified soil is 61.3%, the weight percentage of cement is 13.5%, the weight percentage of microbial agent is 2%, the weight percentage of nutrient source is 2%, the weight percentage of admixture is 1%, and the weight percentage of water is 20.2%. The soil is a powder with good stability; the molar ratio of urea to sodium silicate in the nutrient source is 1:0.8; the stabilizer is lime; and the water retaining agent is diatomaceous earth. The weight percentage of pH regulator in the admixture is 18%, the weight percentage of stabilizer is 62%, and the weight percentage of water retaining agent is 20%, as shown in Table 2.

[0096] Table 2

[0097]

[0098] The formed fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results were: 7d unconfined compressive strength 1.93MPa, fluidity 258.5mm, water loss rate 14.6%. This can indicate that the fluidized solidified soil layer formed after the fluidized solidified soil of Example 2 is applied to embankment reinforcement has a high unconfined compressive strength, suitable water loss rate and fluidity, and can achieve the effect of rapid embankment reinforcement.

[0099] Example 3

[0100] The preparation process of the fluidized solidified soil and the process of applying it to embankment reinforcement are the same as those in Example 1, except that the weight percentage of soil in the fluidized solidified soil is 65.4%, the weight percentage of cement is 11.8%, the weight percentage of microbial agent is 1%, the weight percentage of nutrient source is 1%, the weight percentage of admixture is 0%; the weight percentage of water is 20.8%, as shown in Table 3.

[0101] Table 3

[0102]

[0103] The fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results were: 7d unconfined compressive strength 1.6MPa, fluidity 236.0mm, water loss rate 15.6%. This can show that the unconfined compressive strength and fluidity of the fluidized solidified soil layer formed after the fluidized solidified soil of Example 3 was applied to embankment reinforcement are lower than those of Example 1, and the water loss rate is increased, which can basically achieve the effect of rapid embankment reinforcement.

[0104] Example 4

[0105] The preparation process of the fluidized solidified soil and the process of applying it to embankment reinforcement are the same as those in Example 1, except that the weight percentage of soil in the fluidized solidified soil is 63.07%, the weight percentage of cement is 11.35%, the weight percentage of microbial agent is 1.5%, the weight percentage of nutrient source is 1.5%, the weight percentage of admixture is 1%; the weight percentage of water is 21.58%, as shown in Table 4.

[0106] Table 4

[0107]

[0108] The fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results were: 7d unconfined compressive strength 1.54MPa, fluidity 253.0mm, water loss rate 15.4%. This can indicate that the unconfined compressive strength of the fluidized solidified soil layer formed after the fluidized solidified soil of Example 4 was applied to embankment reinforcement is lower than that of Examples 1-3, the water loss rate is increased, and the fluidity is improved. The improved fluidity is conducive to the rapid realization of embankment reinforcement in large-area paving construction.

[0109] Example 5

[0110] The preparation process of the fluidized solidified soil and the process of applying it to embankment reinforcement are the same as those in Example 1, except that the weight percentage of soil in the fluidized solidified soil is 59.43%, the weight percentage of cement is 13.09%, the weight percentage of microbial agent is 2%, the weight percentage of nutrient source is 2%, the weight percentage of admixture is 1%; the weight percentage of water is 22.48%, as shown in Table 5.

[0111] Table 5

[0112]

[0113] The fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results were: 7d unconfined compressive strength 1.73MPa, fluidity 291.5mm, water loss rate 14.3%. This can indicate that the fluidized solidified soil layer formed after the fluidized solidified soil of Example 5 is applied to embankment reinforcement has a higher unconfined compressive strength, a lower water loss rate, and a higher fluidity, and can more easily reach narrow or difficult-to-pump areas, thereby achieving rapid embankment reinforcement.

[0114] Comparative Example 1

[0115] The preparation process of the fluidized solidified soil and the process of applying it to embankment reinforcement are the same as those in Example 1, except that the weight percentage of soil in the fluidized solidified soil is 54.66%, the weight percentage of cement is 6.47%, the weight percentage of microbial agent is 3%, the weight percentage of nutrient source is 3%, the weight percentage of admixture is 1%; the weight percentage of water is 31.87%, as shown in Table 6.

[0116] Table 6

[0117]

[0118] The fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results were: 7d unconfined compressive strength 0.94MPa, fluidity 198.0mm, water loss rate 31.6%. This shows that after the fluidized solidified soil of Comparative Example 1 was used for embankment reinforcement, the unconfined compressive strength was significantly reduced, the water loss rate was high, and the fluidity was insufficient, resulting in the embankment reinforcement effect not being as significant as that of Examples 1 to 5.

[0119] Comparative Example 2

[0120] The preparation process of the fluidized solidified soil and the process of applying it to embankment reinforcement are the same as those in Example 1, except that the weight percentage of soil in the fluidized solidified soil is 65.96%, the weight percentage of cement is 9.24%, the weight percentage of microbial agent is 2%, the weight percentage of nutrient source is 3%, the weight percentage of admixture is 1.0%; the weight percentage of water is 18.8%, as shown in Table 7.

[0121] Table 7

[0122]

[0123] The fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results were: 7d unconfined compressive strength 0.97MPa, fluidity 210.0mm, water loss rate 16.7%. This shows that after the fluidized solidified soil of Comparative Example 2 was used for embankment reinforcement, the unconfined compressive strength was low, the water loss rate was high, and the fluidity was not ideal, and the effect of rapid embankment reinforcement was not achieved.

[0124] Comparative Example 3

[0125] The preparation process of the fluidized solidified soil and the process of applying it to embankment reinforcement are the same as those in Example 1, except that the weight percentage of soil in the fluidized solidified soil is 55.7%, the weight percentage of cement is 5.62%, the weight percentage of microbial agent is 1%, the weight percentage of nutrient source is 1%, and the weight percentage of admixture is 0.5%; the weight percentage of water is 36.18%, as shown in Table 8.

[0126] Table 8

[0127]

[0128] The fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results are: 7d unconfined compressive strength 0.76MPa, fluidity 270.0mm, water loss rate 32.2%. This shows that the unconfined compressive strength of the fluidized solidified soil layer formed by the fluidized solidified soil in comparative example 3 after being applied to embankment reinforcement is low, and the water loss rate is significantly high. Although the fluidity is good, the overall performance still cannot meet the needs of rapid embankment reinforcement.

[0129] Comparative Example 4

[0130] The preparation process of the fluidized solidified soil and the process of applying it to embankment reinforcement are the same as those in Example 1, except that the weight percentage of soil in the fluidized solidified soil is 65.4%, the weight percentage of cement is 11.8%, the weight percentage of microbial agent is 0, the weight percentage of nutrient source is 0, the weight percentage of admixture is 0.8%, and the weight percentage of water is 20.8%, as shown in Table 9.

[0131] Table 9

[0132]

[0133] The fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results were: 7d unconfined compressive strength 1.17MPa, fluidity 226mm, water loss rate 16.6%. This shows that the fluidized solidified soil layer formed by the fluidized solidified soil of Comparative Example 4 after being applied to embankment reinforcement has low unconfined compressive strength, high water loss rate, and insufficient fluidity, resulting in poor embankment reinforcement effect.

[0134] Comparative Example 5

[0135] The preparation process of the fluidized solidified soil and the process of applying it to embankment reinforcement are the same as those in Example 1, except that the microbial agent and the nutrient source are not included, and the remaining materials are supplemented in equal proportions according to Example 1. The weight percentage of soil in the fluidized solidified soil is 62.9%, the weight percentage of cement is 13.8%, the weight percentage of the microbial agent is 0, the weight percentage of the nutrient source is 0, the weight percentage of the admixture is 1%, and the weight percentage of water is 22.3%, as shown in Table 10.

[0136] Table 10

[0137]

[0138] The fluidized solidified soil layer was tested for unconfined compressive strength, fluidity, durability and other indicators. The test results were: 7d unconfined compressive strength 1.35MPa, fluidity 258.0mm, water loss rate 14.7%. This shows that after the fluidized solidified soil of comparative example 5 was applied to embankment reinforcement, it lacked the reinforcing effect of the microbial agent, and the unconfined compressive strength was low. Although the water loss rate and fluidity were still good, the overall performance was still inferior to the fluidized solidified soil of the present invention.

[0139] The test results of the above embodiments and comparative examples are described as follows, as shown in Table 11:

[0140] Table 11

[0141]

[0142] According to the above-mentioned embodiments and comparative examples of the present invention, by adjusting the proportion of each raw material in the fluidized solidified soil, a fluidized solidified soil layer with high strength, appropriate fluidity and low water loss rate can be obtained, and the ecological solidification of the embankment soil can be achieved.

[0143] Among them, compared with comparative examples 1 to 3, the raw material ratios used in Examples 1 to 5 significantly improve the strength of the prepared fluidized solidified soil layer, significantly reduce the water loss rate, and have the same or improved fluidity, which can effectively achieve the ecological solidification of the embankment soil.

[0144] Compared with Comparative Example 4, the raw materials of Examples 1 to 5 include microbial agents and nutrient solution. The strength of the fluidized solidified soil formed by Examples 1 to 5 is significantly improved, the water loss rate is reduced, and the fluidity is significantly improved, which can effectively achieve the ecological solidification of the embankment soil.

[0145] It is worth mentioning that the 7d unconfined compressive strength of the fluidized solidified soil layer of Example 2 reaches 1.93 MPa. The fluidized solidified soil layer of Example 2 has suitable fluidity and water loss rate, better strength, and better effect for embankment reinforcement.

[0146] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fluidized solidified soil for embankment reinforcement, characterized in that: Including soil, cement, microbial agents, nutrient sources, admixtures and water; Among them, the weight percentage of soil is 55%~68%, the weight percentage of cement is 10%~16%, the weight percentage of microbial agent is 1%~2%, the weight percentage of nutrient source is 1%~2%, the weight percentage of admixture is 0~1.0%, and the weight percentage of water is 20%~25%.

2. The fluidized solidified soil according to claim 1, characterized in that: The soil material is clay and / or silt with cohesiveness and plasticity.

3. The fluidized solidified soil according to claim 1, characterized in that: The cement is PO42.5R silicate cement.

4. The fluidized solidified soil according to claim 1, characterized in that: The microbial agent includes Priesteria aeruginosa, which is suitable for inducing silicate minerals in soil materials to react to generate silicate precipitation and dissolve phosphate in soil materials.

5. The fluidized solidified soil according to claim 1, characterized in that: The nutrient sources include urea, potassium dihydrogen phosphate and sodium silicate; Among them, the molar ratio of urea to sodium silicate is 0.9~1.1, and the molar ratio of urea to potassium dihydrogen phosphate is 1.0~2.

0.

6. The fluidized solidified soil according to claim 1, characterized in that: The additives include a pH regulator, a stabilizer and a water retaining agent; Among them, the weight percentage of the pH adjuster in the admixture is 20% to 30%, the weight percentage of the stabilizer is 40% to 60%, and the weight percentage of the water retaining agent is 10% to 20%.

7. The fluidized solidified soil according to claim 1, characterized in that: The ratio of the mass of the microbial agent to the mass of the nutrient source is 0.8-1.

2.

8. A method for reinforcing an embankment using fluidized solidified soil as claimed in any one of claims 1 to 7, characterized in that: include: Installing a retaining wall outside the embankment to be widened to form a casting space between the embankment to be widened and the retaining wall; pouring the fluidized solidified soil into the pouring space in layers and compacting it to form a fluidized solidified soil layer; as well as The fluidized solidified soil layer formed in the pouring space is covered with a moisture retaining material to maintain the fluidized solidified soil layer.

9. The reinforcement method according to claim 8, characterized in that: The fluidized solidified soil is poured into the pouring space in layers and compacted to a thickness of less than or equal to 30 cm for each layer of the fluidized solidified soil.

10. The reinforcement method according to claim 8, characterized in that: The temperature for curing the fluidized solidified soil layer is 25℃~30℃.

11. The reinforcement method according to claim 8, characterized in that: The unconfined compressive strength of the fluidized solidified soil layer reaches 1.5MPa~2.0MPa.

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