An organic-inorganic composite environmental protection curing agent for shield soil solidification and its preparation method

Abstract

The present invention discloses an organic-inorganic composite environmental protection curing agent for shield soil solidification and its preparation method, which relates to the technical field of shield construction. The organic-inorganic composite environmental protection curing agent of the present invention, calculated by mass parts, the raw materials include the following components: 2 to 2.7 parts of cementitious curing material, 0.5 to 1 part of neutral inorganic curing stabilizer, 2.3 to 2.6 parts of activator, 0.15 to 0.25 parts of reinforcing agent; wherein, the neutral inorganic curing stabilizer is a water-soluble mixture containing Ca<supgt;2+< / supgt;, K<supgt;+< / supgt;, Na<supgt;+< / supgt; and halide ions. The organic-inorganic composite environmental protection curing agent of the present invention can reduce the retention amount of shield soil pollutants, achieve the process reduction of pollutants, and then treat the shield soil into reusable soil with good engineering properties and excellent environmental protection performance, realizing the green and safe utilization of shield soil.

Description

Technical Field

[0001] The present invention relates to the technical field of shield construction, and particularly to an organic-inorganic composite environmental protection curing agent for shield soil solidification and a preparation method thereof. Background Technique

[0002] With the rapid economic development and the acceleration of the urbanization process, the scale and quantity of urban rail transit construction are unprecedented.

[0003] The shield method is a mainstream construction method for subway tunnels. A large amount of shield waste soil will be generated during the shield tunneling process. The traditional treatment method for shield soil is dumping, which not only occupies a large amount of precious cultivated land resources but also has a relatively high treatment cost. More importantly, these shield soils contain a large amount of chemical agents and clay minerals, and the total concentration of toxic chemical substances can be as high as 5000 mg / kg. The shield soil without identification and evaluation is directly dumped on farmland or valley quarries, and the pollutants diffuse into the ecosystem along with the groundwater, causing chronic toxic effects on environmental organisms and human health, and seriously threatening the safety of the ecological environment. Considering from the perspectives of environment and economy, there are many disadvantages in using the dumping method to treat shield soil. Therefore, finding a more effective and economical method to treat shield soil has become a hot issue of common concern around the world.

[0004] At present, the research on shield soil performance improvement technology and materials is still in the exploration stage. The dehydration and solidification mechanism of shield soil is not clear, and there are problems such as single means and low efficiency of synergistic reduction of shield soil pollutants. Usually, reactive dehydration is more commonly used, and generally, cementitious materials are used to treat shield soil, but there is a risk of introducing heavy metal ion pollution while treating shield soil. For shield soil pollutants, there is no targeted fixed reduction material. The existing achievements mainly focus on the fixation and removal of heavy metals for site pollution. The types of pollutants in shield soil and site soil are different, and the existing research results cannot provide reference for the fixed reduction of shield soil pollutants.

[0005] Therefore, in order to achieve on-site rapid pretreatment, centralized resource treatment and green and safe utilization of shield soil, it is urgent to develop environmentally friendly and efficient shield soil performance improvement and pollutant fixed reduction functional materials. Summary of the Invention

[0006] The purpose of the present invention is to provide an organic-inorganic composite environmental protection curing agent for shield soil solidification and a preparation method thereof, so as to solve the problems of low efficiency of on-site shield soil pretreatment dehydration and solidification, difficulty in meeting the requirements for external transportation, and difficulty in reducing and easy residue of shield soil pollutants in centralized site treatment.

[0007] To achieve the above purpose, the present invention provides the following scheme:

[0008] The present invention provides an organic-inorganic composite environmental protection curing agent for shield soil solidification. By mass, the raw materials include the following components:

[0009] 2 parts to 2.7 parts of gelling and solidifying material, 0.5 part to 1 part of neutral inorganic solidification stabilizer, 2.3 parts to 2.6 parts of activator, 0.15 part to 0.25 part of enhancer;

[0010] The neutral inorganic solidification stabilizer is a water-soluble mixture containing Ca 2+ , K + , Na + and halide ions, specifically a rich ion water-soluble mixture composed of inorganic compounds containing Ca 2+ , K + , Na + and halide ions.

[0011] Further, the gelling and solidifying material is composed of raw materials in the following mass ratio: mineral powder: quicklime: slaked lime: lime powder: gypsum dihydrate = 73 - 84: 2 - 4: 0 - 4: 15 - 25: 1.5 - 7.5.

[0012] In the present invention, the gelling and solidifying material is used for dehydrating and strengthening shield soil. The components and functions of each component in the gelling and solidifying material are as follows:

[0013] Mineral powder, the main components are SiO2, Al2O3 and CaO, and at the same time contains a small amount of other components such as MgO, Fe2O3, etc.; the higher the content of Al2O3, CaO and MgO, the better the activity of the mineral powder. In the present invention, the mineral powder with the total mass of the three being more than 56% is preferably used. This mineral powder has good activity, can fully participate in the solidification reaction, enhance the hardening rate and strength of the gel body, and at the same time reduce the heat release and alkalinity during the solidification process, which plays an important role in moderating the solidification reaction and improving the properties of shield soil.

[0014] Quicklime, the main component is CaO, has strong water absorption, and has a good promoting effect on realizing dehydration and rapid setting during the shield soil solidification process.

[0015] Slaked lime (Ca(OH)2) is used as a soil acidity preventer and curing agent to reduce the acidity of shield soil, thereby playing a role in improving the soil structure and properties.

[0016] Lime powder is a white powdery substance mainly composed of CaCO3, and also contains relatively high calcium, magnesium, iron and other elements, and other chemical substances can be added according to needs to improve the performance.

[0017] Gypsum dihydrate is a white powdery substance with the chemical formula CaSO4·2H2O. Gypsum dihydrate contains a large amount of calcium sulfate dihydrate and also contains a small amount of impurities such as alumina, iron oxide, and silica. Gypsum dihydrate has good hygroscopicity, heat insulation, fire resistance, and chemical corrosion resistance.

[0018] Further, the activator is a mixture of sodium silicate and sodium hydroxide with a mass ratio of 1.9 - 2.5:0.1 - 0.4; the modulus of the sodium silicate is 1.0.

[0019] Further, the intensifier is triisopropanolamine.

[0020] In the present invention, the neutral inorganic solidification stabilizer promotes the hydration reaction of the cementitious solidification material, reduces the moisture content, makes the shield soil particles easier to cement, improves the strength and durability, generates stable hydrates (crystals), and forms solidified soil with sufficient strength. At the same time, the neutral inorganic solidification stabilizer adheres to the soil particles and inhibits the decomposition of humic acid and lignic acid in the shield soil into low-molecular compounds such as alcohols and carboxylic acids.

[0021] The neutral inorganic solidification stabilizer of the present invention promotes the coagulation reaction of silicon dioxide (SiO2) and alumina (Al2O3) in the cementitious solidification material with heavy metal ions in the shield soil particles to generate insoluble salts, which can effectively reduce the shield soil pollutants below the environmental standard value.

[0022] In the present invention, sodium silicate can undergo a polymerization reaction with the shield soil and penetrate into the shield soil to continue to undergo a chemical reaction with the soil body to play a cementing role.

[0023] In the present invention, sodium hydroxide, as an alkaline activator, activates the reaction of the cementitious solidification material with the shield soil to generate a cementitious substance, causing the surface layer of the soil particles to gradually expand and soften, and then making the adjacent soil particles closely contact and fuse with each other to form a relatively high-strength whole, improving the mechanical properties of the solidified soil.

[0024] The present invention also provides the application of the above organic-inorganic composite environmental protection type curing agent in the solidification of shield soil.

[0025] The present invention further provides a method for solidifying shield soil, which includes the following steps: adding the above organic-inorganic composite environmental protection type curing agent into the shield soil according to the raw material ratio, and then adding mixing water to realize the solidification of the shield soil.

[0026] Further, based on the dry mass of the shield soil, the incorporation ratio of the organic-inorganic composite environmental protection type curing agent in the shield soil is 27.5% - 30%.

[0027] Further, mixing water is added at a water-solid ratio of 25% to 28%; wherein, the water-solid ratio refers to the percentage of mixing water to the total mass of the dry mass of shield soil and the solidifying agent.

[0028] Further, after adding the mixing water, it further includes the step of adding a defoaming agent to the obtained mixture; wherein, the addition amount of the defoaming agent is preferably 3% of the mass of the mixture obtained after adding the mixing water.

[0029] The defoaming agent is quicklime.

[0030] Further, the mixing temperature is room temperature (18 - 23 °C).

[0031] In the present invention, the cementitious solidifying material, neutral inorganic solidifying stabilizer, activator, and enhancer can generate stable hydrated coagulants through secondary hydration reactions with mixing water during the solidification process of shield soil, achieving the improvement of the properties of shield soil. Under the condition of meeting the same performance indicators, the cost is reduced by > 50%; after treatment and disposal, the release rate of harmful substances in shield soil is reduced by > 50%. The obtained solidified soil has high strength, good durability, fast solidification speed, low cost, and environmental friendliness, and can meet the requirements of different scenarios, such as backfill planting soil, sponge soil, non-fired bricks, blocks, building materials, etc., realizing the rational utilization of waste shield soil into multifunctional solidified soil.

[0032] The present invention makes the shield soil generate cementitious solidification through hydration reactions, and at the same time converts some pollutant ions into poorly soluble crystals to prepare solidified soil with high strength and low pollution.

[0033] The present invention realizes the reduction of pollutant retention through multiple levels in the treatment and disposal process, achieving the process reduction of pollutants; treating the shield soil into reusable soil with good engineering properties and excellent environmental protection performance, realizing the green and safe utilization of shield soil.

[0034] The present invention discloses the following technical effects:

[0035] The solidifying agent of the present invention can treat waste shield soil into geotechnical materials with good engineering properties, not only solving the problems such as the occupation of farmland caused by the dumping of shield soil, but also realizing resource recycling, achieving the purpose of turning waste into treasure. Moreover, the prepared solidified soil products replace building materials such as clay, sand and gravel, and cement, which can save costs and create indirect economic benefits.

[0036] Urban construction has a huge demand for building materials. In the past, it basically relied on conventional building materials such as clay and cement, and the production of cement is a high-energy-consuming and high-emission industry. The present invention realizes the resource utilization of shield soil, belongs to the "comprehensive utilization of three wastes" industry, reduces the consumption of natural resources, promotes carbon emission reduction, and effectively realizes the quality-based utilization of building materials.

[0037] The solidified soil obtained by solidifying shield soil with the present invention has high strength, good durability, fast solidification speed, low cost, and environmental friendliness. It not only avoids the disadvantages of large dry shrinkage, easy cracking, and poor water stability of inorganic materials, but also makes full use of the advantages of organic materials, realizes the effective modification of shield soil, and has great market space.

[0038] The release rate of harmful substances in the shield soil treated with the present invention is reduced by more than 50%. Heavy metal ions (such as Pb 2+ , Cd 2+ , Cu 2+ , etc.) in the shield soil react with certain anions (such as OH - , CO3 2- , etc.) in the solution to form water-insoluble precipitates, so that the heavy metals change from ionic state to crystal state, are hardly absorbed by plants and animals, and are insoluble in groundwater for a long time. This can reduce the huge resource waste and environmental negative effects caused by the stacking of shield soil, and realize the green and safe utilization of shield soil.

[0039] The present invention can adjust the raw material ratio to obtain solidifying agents with different properties, so that they show different characteristics after solidifying with shield soil, to meet the needs of various engineering applications, such as backfill planting soil, sponge soil, non-fired bricks, blocks, building materials, etc., and has a wide range of applications.

[0040] The present invention will have an all-round and profound impact on aspects such as building a "waste-free city" and a "low-carbon city", promoting the improvement of the urban ecological environment, reducing the emission of bulk solid waste, improving the high-value utilization of waste, reducing the dependence on natural resources, assisting the construction of a conservation-oriented society, and promoting the development of circular economy and the dual-carbon strategy, and has inestimable comprehensive benefits. Brief Description of the Drawings

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0042] Figure 1 It is the diagram of the unconfined compressive strength test of the soaked and unsoaked solidified soil prepared in Examples 1-6 of the present invention for 7 days and 28 days.

[0043] Figure 2 It is the strength diagram of the solidified soil prepared in Examples 1-6 of the present invention after 5 freeze-thaw cycles.

[0044] Figure 3 It is the permeability coefficient diagram of the solidified soil prepared in Examples 1-6 of the present invention for 28 days.

[0045] Figure 4 It is the mass loss diagram of the cured soil under sulfurous acid erosion prepared in Examples 1-6 of the present invention.

[0046] Figure 5 It is the diagram of the pollutant concentration and environmental safety risk of the cured soil prepared in Examples 1-6 of the present invention. Detailed implementation manners

[0047] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be regarded as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0048] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0049] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0050] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are only exemplary.

[0051] Regarding "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0052] "Room temperature" in the present invention is counted as 18 - 23 °C unless otherwise specified.

[0053] All raw materials used in the following examples of the present invention are commercially available products.

[0054] In the following embodiments of the present invention: the total mass ratio of Al2O3, CaO and MgO in the mineral powder is 56%; the NaOH is of industrial grade and the solid content of NaOH is ≥99%; the mixing water is drinking water; the source of the shield soil (dry soil) is a certain shield section of the Jinan subway.

[0055] Example 1

[0056] Accurately weigh 54 g of the cementitious solidifying material, 10 g of the neutral inorganic solidifying stabilizer, 50 g of water glass, 2 g of sodium hydroxide, 4 g of triisopropanolamine, 130 g of mixing water and 400 g of shield soil.

[0057] Among them, the mass ratio of each component in the cementitious solidifying material is: mineral powder: quicklime: slaked lime: lime powder: gypsum dihydrate = 77:2:3:15:3. The neutral inorganic solidifying stabilizer is a mixture of CaCl2, KF, and NaCl with a molar ratio of 7:2:1.

[0058] The solidification process of the shield soil is as follows:

[0059] (1) Mix the cementitious solidifying material, the neutral inorganic solidifying stabilizer and triisopropanolamine evenly to obtain a mixture;

[0060] (2) Pour the mixture obtained in step (1) and the shield soil into a cement mortar mixer, and stir at a low speed of 60 r / min for 5 min to make them mix evenly to obtain a mixed soil;

[0061] (3) Pour the water glass with a modulus of 1.0 into the mixed soil obtained in step (2), and then stir at a high speed of 120 r / min for 5 min; then add sodium hydroxide and the mixing water to make the water-solid ratio reach 25%. After thoroughly stirring evenly, add 3% of the defoaming agent (quicklime) based on the mass of the obtained mixture, and accelerate the mixing for 2 min to remove the air bubbles in the freshly mixed soil mass to prepare the solidified soil.

[0062] Apply a layer of vaseline evenly on the inner wall of a cylindrical mold with an inner diameter of 40 mm and a height of 80 mm, and then take the solidified soil and load it into the mold in three times for compaction, with 20 strikes each time to prepare the muck solidified soil specimen. Demold and number the solidified soil specimen, and place it in a curing box for curing under standard curing conditions. A total of 15 specimens are prepared to conduct the unconfined compressive strength tests of immersion and non-immersion for 7 days and 28 days respectively; a total of 12 specimens are prepared to conduct the 28-day freeze-thaw cycle test, permeability test, durability test, and pollutant dissolution amount test, with 3 parallel tests in each group. And a control group is set up.

[0063] Among them, the curing agent produced by a certain Japanese company is used in the control group, and its main components are cement: fly ash: gypsum = 4:15:3 (mass ratio). The preparation process of the solidified soil is as follows:

[0064] (1) Weigh accurately 120 g of the curing agent, 130 g of the mixing water, and 400 g of the shield soil.

[0065] (2) Pour the curing agent and the shield soil obtained in step (1) into a cement mortar mixer, and mix them evenly at a low speed of 60 r / min for 5 min to obtain the mixed soil.

[0066] (3) Add the mixing water to the mixed soil to make the water-solid ratio reach 25%, and mix it at an accelerated speed of 120 r / min for 2 min. After thorough mixing, prepare the control group of solidified soil.

[0067] Apply a uniform layer of vaseline on the inner wall of a cylindrical mold with an inner diameter of 40 mm and a height of 80 mm. Then, take the control group of solidified soil and load it into the mold in three times for compaction, with 20 strikes for compaction each time, to prepare the control group sample of the muck solidified soil. Demold and number the control group samples, and place them in a curing box for curing under standard curing conditions. A total of 15 samples are prepared for the unconfined compressive strength tests with and without immersion for 7 days and 28 days; a total of 12 samples are prepared for the 28-day freeze-thaw cycle test, permeability test, durability test, and pollutant leaching test, with 3 parallel tests in each group.

[0068] Example 2

[0069] Weigh accurately 54 g of the cementitious solidifying material, 10 g of the neutral inorganic solidifying stabilizer, 50 g of the water glass, 2 g of the sodium hydroxide, 4 g of the triisopropanolamine, 130 g of the mixing water, and 400 g of the shield soil.

[0070] Among them, the mass ratio of each component in the cementitious solidifying material is: mineral powder: quicklime: slaked lime: lime powder: gypsum dihydrate = 80:2:0:15:3.

[0071] The solidification process of the shield soil and the performance verification of the obtained solidified soil are the same as those in Example 1.

[0072] Example 3

[0073] Weigh accurately 44 g of the cementitious solidifying material, 15 g of the neutral inorganic solidifying stabilizer, 47 g of the water glass, 1 g of the sodium hydroxide, 3 g of the triisopropanolamine, 140 g of the mixing water, and 400 g of the shield soil.

[0074] Among them, the mass ratio of each component in the cementitious solidifying material is: mineral powder: quicklime: slaked lime: lime powder: gypsum dihydrate = 77:2:3:15:3.

[0075] The solidification process of the shield soil and the performance verification of the obtained solidified soil are the same as those in Example 1.

[0076] Example 4

[0077] Accurately weigh 48 g of cementitious solidification material, 15 g of neutral inorganic solidification stabilizer, 48 g of water glass, 3 g of sodium hydroxide, 5 g of triisopropanolamine, 131 g of mixing water and 400 g of shield soil.

[0078] Among them, the mass ratio of each component in the cementitious solidification material is: mineral powder: quicklime: hydrated lime: lime powder: gypsum dihydrate = 77:2:3:15:3.

[0079] The solidification process of the shield soil and the performance verification of the obtained solidified soil are the same as those in Example 1.

[0080] Example 5

[0081] Accurately weigh 46 g of cementitious solidification material, 18 g of neutral inorganic solidification stabilizer, 45 g of water glass, 1 g of sodium hydroxide, 4 g of triisopropanolamine, 136 g of mixing water and 400 g of shield soil.

[0082] Among them, the mass ratio of each component in the cementitious solidification material is: mineral powder: quicklime: hydrated lime: lime powder: gypsum dihydrate = 77:2:3:15:3.

[0083] The solidification process of the shield soil and the performance verification of the obtained solidified soil are the same as those in Example 1.

[0084] Example 6

[0085] Accurately weigh 46 g of cementitious solidification material, 20 g of neutral inorganic solidification stabilizer, 46 g of water glass, 4 g of sodium hydroxide, 3 g of triisopropanolamine, 131 g of mixing water and 400 g of shield soil.

[0086] Among them, the mass ratio of each component in the cementitious solidification material is: mineral powder: quicklime: hydrated lime: lime powder: gypsum dihydrate = 77:2:3:15:3.

[0087] The solidification process of the shield soil and the performance verification of the obtained solidified soil are the same as those in Example 1.

[0088] Figure 1Graphs of the unconfined compressive strength tests of the solidified soil prepared in Examples 1-6 (Cases 1-6) of the present invention for 7 days and 28 days with and without immersion in water. The results show that the compressive strength of the solidified soil obtained by consolidating shield soil with the solidifying agent of the present invention is greatly improved. The reason for the improvement of the strength of the solidified soil by the solidifying agent of the present invention is as follows: The solid particles in the solidified soil are composed of inorganic mineral particles, mainly including limestone, silica, anorthite, etc., which have stable physical and chemical properties and low internal activity; the content of mineral powder in the solidifying agent is relatively high, making the mixed soil have higher hydration activity. During the solidification process, limestone, silica, etc. participate in the reaction to generate calcium silicate hydrate and calcium sulfoaluminate hydrate. The calcium sulfoaluminate hydrate crystals overlap with each other, and the calcium silicate hydrate gel cross-climbs, connecting the dispersed shield soil particles together to form a dense three-dimensional spatial structure, increasing the compressive strength of the solidified soil. At the same time, water glass is used as an activator, increasing the content of active SiO2 and OH- in the system, accelerating the activation and reaction rate, and facilitating the polymerization reaction of substances; triisopropanolamine is used as a strength enhancer to promote the dissolution rate of Ca 2+ 、Al 3+ 、Si 4+ ions in the early stage, which is also beneficial to the formation of gels such as calcium silicate hydrate, thereby increasing the compressive strength.

[0089] Figure 2 Graph of the strength of the solidified soil prepared in Examples 1-6 (Cases 1-6) of the present invention after 5 freeze-thaw cycles. The results show that the strength loss rate of the solidified soil in Examples 1-6 of the present invention is much smaller than that of the conventional solidified soil, and the anti-freezing effect is remarkable.

[0090] Figure 3 Graph of the permeability coefficient of the solidified soil prepared in Examples 1-6 (Cases 1-6) of the present invention for 28 days. The results show that the permeability coefficient of the solidified soil prepared by the present invention is significantly smaller than that of the conventional solidified soil, and the anti-seepage effect is greatly improved.

[0091] Highly permeable building materials can be prepared by means of increasing the amount of quicklime, reducing the water glass content, shortening the mixing time, etc.

[0092] Figure 4 Graph of the mass loss of the solidified soil prepared in Examples 1-6 (Cases 1-6) of the present invention due to sulfurous acid erosion. The results show that the durability of the solidified soil prepared in Examples 1-6 of the present invention can be up to nearly 7 times that of the conventional solidified soil.

[0093] Figure 5 Graph of the pollutant concentration and environmental safety risk of the solidified soil prepared in Examples 1-6 (Cases 1-6) of the present invention. The results show that the pollutant concentration and environmental safety risk of the solidified soil prepared by the present invention are greatly reduced compared with those of the untreated shield soil.

[0094] In terms of compressive strength, the performance of Example 1 of the present invention is the best, and the prepared solidified soil has high strength. The unconfined compressive strengths at 7 days and 28 days are 4.98 MPa and 9.54 MPa respectively. The unconfined compressive strengths at 7 days and 28 days of the control group are 1.55 MPa and 2.24 MPa respectively; the durability of the solidified soil in Example 1 of the present invention is the best, and the mass loss rate is only 1%, which is about 6 times higher than 6.7% of the control group.

[0095] The dosages of each raw material of the solidifying agent in Example 1 corresponding to the shield soil are as follows: the dosage of the cementitious solidifying material is 8.3% (slag powder: quicklime: hydrated lime: lime powder: dihydrate gypsum = 77:2:3:15:3), the dosage of the neutral inorganic solidifying stabilizer is 1.5%, the water glass modulus is 1.0, the water glass dosage is 8.0%, the triisopropanolamine dosage is 0.6%, and the mixing water dosage is 20%.

[0096] According to the requirements for the unconfined compressive strength of solidified soil at 7-day age in the Technical Specification for Application of Road Solidified Soil T / CECS737—2020, the solidified soils of Examples 1-6 can all be used as subbase roadbed fillers.

[0097] According to the Technical Specification for Canal Seepage Control Engineering SL / 18—2004, the permeability coefficients of the solidified soils of Examples 1-6 are all less than 1×10 -6 cm / s and can be used as canal seepage control materials for seasonal water conveyance and perennial water conveyance in frost-free areas with mild climates.

[0098] The above-described embodiments are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An organic-inorganic composite environmentally friendly curing agent for shield soil curing, characterized in that: The raw materials include the following components in terms of mass: 2 to 2.7 parts of gelling and curing material, 0.5 to 1 part of neutral inorganic curing stabilizer, 2.3 to 2.6 parts of activator, and 0.15 to 0.25 parts of reinforcing agent; The neutral inorganic curing stabilizer contains Ca 2+ , K + 、Na + and water-soluble mixtures of halide ions; The gelling and curing material is composed of the following raw materials in mass ratio: composition: Mineral powder: quicklime: slaked lime: lime powder: dihydrate gypsum = 73-84: 2-4: 0-4: 15-25: 1.5-7.5; The activator is a mixture of water glass and sodium hydroxide in a mass ratio of 1.9-2.5:0.1-0.4; the modulus of the water glass is 1.0-1.3; and the enhancer is triisopropanolamine.

2. Use of the organic-inorganic composite environmentally friendly curing agent as claimed in claim 1 in shield soil curing.

3. A method for solidifying shield soil, characterized in that: The method comprises the following steps: adding the organic-inorganic composite environmentally friendly curing agent described in claim 1 into the shield soil according to the raw material ratio, and then adding mixing water according to a water-solid ratio of 25% to 28% to achieve the curing of the shield soil; Calculated based on the dry mass of the shield soil, the mixing ratio of the organic-inorganic composite environmentally friendly curing agent in the shield soil is 27.5% to 30%.

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