Low-carbon solid waste-based shield mortar, preparation method and application thereof

Abstract

The application provides a low-carbon solid waste-based shield mortar, and is characterized in that: the raw materials of the mortar include, in terms of mass percentage, 8-14% of industrial solid waste-based cementitious material, 6-10% of cement, 18-22% of building solid waste-based admixture, 26-30% of building waste recycled aggregate, 10-14% of light sand and 15-20% of waste slurry, and the balance is water reducing agent; the building solid waste-based admixture includes light brick waste residue powder, the raw material of the light brick waste residue powder is at least one of aerated concrete waste residue, foamed concrete waste residue or sintered brick waste residue, and the specific surface area of the light brick waste residue powder is 300-340 m 2 / kg; the raw material of the light sand is at least one of aerated concrete waste residue and foamed concrete waste residue, and the particle size of the light sand is not greater than 4.75 mm. The application solves the problem of how to reduce carbon emissions and improve the effective utilization rate of building solid waste under the premise of improving material performance, and the low-carbon solid waste-based shield mortar provided by the application has high solidification rate, strong water retention, good water dispersion resistance, controllable setting time and excellent construction performance.

Description

Technical Field

[0001] This invention relates to the field of shield tunneling mortar technology, and in particular to a low-carbon solid waste-based shield tunneling mortar, its preparation method, and its application. Background Technology

[0002] Shield tunneling is currently the most commonly used construction method for urban underground rail transit projects due to its advantages such as mature technology, safety, environmental friendliness, and minimal impact on surface traffic. However, because the diameter of the shield machine's cutterhead is larger than the diameter of the shield tail, the outer diameter of the tunnel lining is smaller than the diameter of the excavated tunnel, creating a gap of approximately 50mm thick at the shield tail. This gap causes the surrounding soil to be suspended from the tunnel lining, which, if not properly addressed, can lead to settlement, deformation, or even collapse of the surrounding soil. To solve this problem, current engineering practices employ a method of simultaneous grouting behind the tunnel lining wall at the shield tail, referred to as shield wall grouting. This is an essential and crucial procedure in shield tunneling construction.

[0003] Traditional grouting materials are mainly prepared using cement, sand, bentonite, and additives as raw materials. This not only consumes a large amount of non-renewable resources and results in high carbon emissions, but also increases costs due to the use of numerous additives. Currently, grouting materials prepared using various construction or industrial solid wastes as raw materials are increasingly common; however, their solid waste utilization rate is often low, and the material's performance still largely depends on the bentonite or additive composition. For example:

[0004] Patent application number 202210289711.X discloses a shield tunneling grouting material, which uses some conventional raw materials, including cement, fly ash, sand, bentonite, thickener, expansion agent and water-reducing agent. The final shield tunneling grouting material has an improved setting speed and is suitable for water-rich strata with high permeability. However, its solid waste utilization rate is low, and the proportion of ordinary silicate cement is high, resulting in high carbon emissions of the single-liquid grout. In addition, this solution also consumes a large amount of limited resources such as sand, gravel and bentonite, and adds a lot of functional additives, resulting in high costs and limiting its widespread adoption.

[0005] Patent application number 202111574977.0 discloses a low-carbon, impermeable, all-solid-waste grouting material. Its matrix material includes solid waste materials such as desulfurized gypsum, slag, mineral powder, and fly ash, as well as bentonite, fine aggregate, etc. This grouting material activates the potential cementitious activity of the matrix material by adding a composite alkaline activator, giving the matrix material the conditions for engineering application. Although it completely replaces cement with solid waste, it should be noted that alkaline-activated cementitious materials still have some problems, such as short setting time, large shrinkage, and easy cracking. Therefore, there are some drawbacks in actual shield tunneling grouting construction.

[0006] Furthermore, according to statistics from the China Building Energy Conservation Association, the total carbon emissions from the entire building process in China in 2020 amounted to 5.08 billion tons of carbon dioxide, accounting for 50.9% of the national total carbon emissions. Against the backdrop of the national goal of building a "resource-saving and environment-friendly" society, how to reduce carbon emissions and improve the effective utilization rate of building solid waste while ensuring material performance are problems that materials scientists should address. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a low-carbon solid waste-based shield tunneling mortar with high consolidation rate, strong water retention, good water dispersion resistance, controllable setting time, and excellent construction performance. It solves the problem of how to reduce carbon emissions and improve the effective utilization rate of construction solid waste while improving material performance.

[0008] According to an embodiment of the present invention, a low-carbon solid waste-based shield tunneling mortar is provided. The raw materials used in the mortar, by mass percentage, include 8-14% industrial solid waste-based cementitious materials, 6-10% cement, 18-22% construction solid waste-based admixtures, 26-30% recycled construction waste aggregates, 10-14% lightweight sand, and 15-20% waste slurry water, with the remainder being a water-reducing agent.

[0009] Construction solid waste-based admixtures include lightweight brick waste powder, wherein the raw material for the lightweight brick waste powder is at least one of aerated concrete waste, foamed concrete waste, or sintered brick waste, and its specific surface area is 300-340 m². 2 / kg;

[0010] The raw materials used for lightweight sand are at least one of aerated concrete waste residue and foamed concrete waste residue, and their particle size is not greater than 4.75mm.

[0011] The technical principle of this invention is as follows:

[0012] The shield tunneling mortar of the present invention is made of hydraulic cementitious materials (cement and industrial solid waste-based cementitious materials), building solid waste-based admixtures, fine aggregates (light sand and recycled aggregates from construction waste), water-reducing agents, and waste slurry.

[0013] Cement possesses inherent hydraulic properties; after undergoing a hydration reaction, it solidifies and hardens into a specific spatial structure, with hydration products including calcium hydroxide. Industrial solid waste-based cementitious materials are entirely derived from industrial solid waste, which possesses potential hydraulic cementitious activity. Under activating effects (such as the mutual activation between its various components or the alkaline activation effect brought about by the calcium hydroxide hydration product of cement), it can exhibit high hydraulic properties, producing strength similar to cement. Furthermore, shield tunneling mortar does not have high strength requirements; replacing part of the cement with industrial solid waste-based cementitious materials, with its inherent activity plus the activity activated by cement or its own components, is sufficient to meet the needs of shield tunneling construction.

[0014] The building solid waste-based admixture is mainly made from building solid waste, which contains a large amount of aerated concrete waste, foamed concrete waste, or sintered brick waste. This lightweight, porous building solid waste material has many internal pores (micropores). After being crushed and ground into powder of a certain fineness, the presence of micropores makes the surface of the finely ground powder particles uneven, greatly increasing the roughness and specific surface area, which in turn greatly increases the water demand. This significantly improves the water absorption and water retention of the material, giving the shield mortar of this invention good anti-water dispersion and anti-bleeding properties. At the same time, the admixture has a high water absorption rate, strong water retention, and low shrinkage, so the building solid waste-based admixture also has a certain benefit in increasing the mortar consolidation rate.

[0015] The fine aggregate is also made entirely from construction solid waste, including a certain amount of lightweight sand. The lightweight sand is also made from lightweight porous construction solid waste, namely, aerated concrete waste or foamed concrete waste. After the lightweight porous construction solid waste is crushed into fine aggregate, it retains a large number of pores, which contain sufficient through-holes to absorb and retain water, thereby regulating the internal humidity of the mortar and playing a better internal curing role. This significantly reduces the shrinkage of the shield mortar and improves the consolidation rate of the shield mortar. At the same time, it works synergistically with the construction solid waste-based admixture to improve the anti-water dispersion and anti-bleeding properties of the shield mortar.

[0016] After the raw materials of the shield tunneling mortar of the present invention are mixed, the admixtures and fine aggregates are bonded together under the hydration action of cement and industrial solid waste-based cementitious materials. The hydraulic cementitious materials provide the main skeleton and strength; the fine aggregates provide support; the surface roughness of the building solid waste-based admixture powder is large, ensuring that the shield tunneling mortar has good water retention and anti-water dispersion properties; the lightweight sand in the fine aggregate, with its numerous internal pores absorbing water, provides good internal curing, ensuring a high consolidation rate of the shield tunneling mortar; and the water-reducing agent provides a certain degree of fluidity, improving the workability of the shield tunneling mortar and making it easier to fill the gaps at the shield tail more evenly. Furthermore, the setting time of the shield tunneling mortar can be flexibly controlled by adjusting the water-cement ratio, the fineness of the powders, and the admixture ratio, making it more suitable for the needs of shield tunneling construction. Therefore, through the combined effect of the various raw materials, a low-carbon solid waste-based shield tunneling mortar with high consolidation rate, strong water retention, good anti-water dispersion properties, controllable setting time, and excellent workability is finally obtained.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) It is mainly based on solid waste, with high utilization rate, saving resources and being green and low-carbon. Traditional cement-based building materials consume a lot of energy and generate a lot of carbon emissions during the production process. In addition, existing technologies mostly use non-renewable mineral resources such as bentonite to improve mortar performance. However, in the solid waste-based shield mortar of this invention, cement accounts for no more than 10% of the raw materials, and the rest are basically all from industrial or construction solid waste, especially construction solid waste. Compared with traditional building materials, it has low carbon emissions and saves resources, and also partially alleviates the environmental pollution problem caused by the accumulation of construction solid waste, providing a new way for the resource utilization of construction solid waste. Moreover, the construction solid waste utilized in this invention does not rely on a few types, but comprehensively utilizes a variety of construction solid wastes through the control of grinding fineness and different proportions. Various solid wastes promote each other and synergistically improve the performance of shield mortar, thereby greatly improving the utilization rate of solid waste.

[0019] (2) High consolidation rate and good construction performance. Light sand contains a large number of pores, which has good water storage capacity and can play a good internal curing role after absorbing water; and light sand itself is also a hardening material, which will not shrink under self-drying conditions; therefore, the addition of light sand can significantly reduce the shrinkage of shield mortar, improve the consolidation rate of shield mortar, and at the same time synergistically improve the anti-water dispersion and anti-bleeding properties of shield mortar. In addition, the shield mortar of the present invention has a consistency loss of less than 10 mm over 3 hours and a flowability loss of less than 10 mm over 3 hours, so it can maintain good construction performance for a long time.

[0020] (3) It has strong water retention, good resistance to water dispersion and bleeding. The building solid waste-based admixture is mainly made of lightweight brick waste powder. Its powder particles have a high surface roughness, a large specific surface area, high water demand, and strong water retention. Even without adding any functional additives, the shield mortar also has good resistance to water dispersion and bleeding, and at the same time, it synergistically improves the consolidation rate of the shield mortar. Its water retention rate is above 99%, and the segregation degree is less than 10mm. During the shield tunneling process, it can better resist the erosion of groundwater and ensure the quality of the project.

[0021] (4) Controllable performance. By controlling the raw material ratio, particle size or powder fineness, key technical indicators such as the setting time, water retention, consolidation rate, activity coefficient and water demand ratio of shield mortar can be effectively controlled.

[0022] (5) The raw materials are simple and readily available, the cost is low, and the mortar has good performance. The raw materials used are mainly solid waste, with few admixtures and only a small amount of water-reducing agent added. The raw materials are simple and readily available, which reduces the cost while achieving good water retention, low drying shrinkage, good fluidity and strength. The construction performance is excellent, and it has good promotion and application value in shield tunneling grouting construction.

[0023] Preferably, the raw materials used in the industrial solid waste-based cementitious material, by mass percentage, include 42%-48% granulated blast furnace slag, 38-46% steel slag, 0-8% fly ash, 6-10% iron tailings, and 2-6% industrial by-product gypsum; and its specific surface area is 390-440 m². 2 / kg.

[0024] Beneficial effects: These industrial solid wastes have excellent hydraulic cementitious activity under activating action; replacing part of the cement with these industrial solid wastes not only greatly saves cement consumption and reduces carbon emissions, but also improves the hydraulic properties of the mortar by activating the interaction between these mineral components and between the mineral components and cement, thereby significantly increasing the strength of the mortar.

[0025] Preferably, the raw materials used in the industrial solid waste-based cementitious material, by mass percentage, include 44% granulated blast furnace slag, 39% steel slag, 6-8% fly ash, 6-10% iron tailings, and 2-4% industrial by-product gypsum; and its specific surface area is 390-410 m². 2 / kg.

[0026] Preferably, the raw materials used in the industrial solid waste-based cementitious material, by mass percentage, include 42% granulated blast furnace slag, 46% steel slag, 2-6% fly ash, 6-8% iron tailings, and 2-3% industrial by-product gypsum; and its specific surface area is 390-410 m². 2 / kg.

[0027] Preferably, the raw materials used in the building solid waste-based admixture, by mass percentage, include 46-52% lightweight brick waste powder, 28-36% recycled micro powder, and 16-26% ceramsite powder; and its specific surface area is 280-320 m². 2 / kg.

[0028] Beneficial effects: The admixture is mainly composed of construction solid waste. Adding it to shield tunnel mortar can greatly save the amount of cement or sand and gravel used, reducing costs. On the other hand, after the above construction solid waste is ground into fine powder, its water absorption and water retention properties are greatly increased. While improving the water dispersion resistance and water bleeding resistance of shield tunnel mortar, it can also synergistically improve the strength of the mortar.

[0029] Preferably, the raw materials used in the building solid waste-based admixture, by mass percentage, include 50% lightweight brick waste powder, 33% recycled micro powder, and 17% ceramsite powder; and its specific surface area is 280 m². 2 / kg.

[0030] Preferably, the raw material for the recycled micro powder is concrete waste residue, and its specific surface area is 240-280 m². 2 / kg; the specific surface area of ​​ceramsite powder is 300-340m². 2 / kg.

[0031] Beneficial effects: On the one hand, in addition to lightweight brick waste powder, the other component of the admixture, which accounts for a large proportion, is recycled micro powder, which is also made from construction solid waste. That is, apart from ceramsite powder, all other components of the admixture are made from construction solid waste. The high proportion of construction solid waste reduces carbon emissions and costs. On the other hand, controlling the fineness of recycled micro powder and ceramsite powder results in a larger specific surface area and a larger water demand, thus improving water retention. Together with lightweight brick waste powder, they synergistically enhance the anti-water dispersion and anti-bleeding properties of the shield mortar.

[0032] Preferably, the raw material used for recycled aggregate from construction waste is waste concrete blocks with a particle size not exceeding 4.75 mm and a fineness modulus of 2.3-2.6.

[0033] Beneficial effects: Recycled aggregate from construction waste is fine aggregate made by crushing and screening waste concrete blocks after the steel bars are removed. Its particle size and fineness are controlled within a suitable range, which not only realizes the effective utilization of construction waste, but also makes the performance of shield tunneling mortar optimal.

[0034] On the other hand, according to embodiments of the present invention, a method for preparing the aforementioned low-carbon solid waste-based shield tunneling mortar is also provided, comprising the following steps:

[0035] (1) Preparation of industrial solid waste-based cementitious materials: After drying the industrial solid waste materials, they are mixed evenly and then ground to a certain fineness to obtain industrial solid waste-based cementitious materials.

[0036] (2) Preparation of building solid waste-based admixture: Dry building solid waste materials such as lightweight brick waste residue, then crush them into particles with a particle size of 0.075-4.75mm, then grind them to a certain fineness and mix them evenly.

[0037] (3) Preparation of recycled aggregate from construction waste: The steel bars in the construction waste are removed, and then crushed into particles with a particle size of 0.075-4.75mm. The excess powder is then screened out to make the recycled aggregate from construction waste.

[0038] (4) Preparation of light sand: The raw materials used for light sand are dried, crushed to particles with a particle size of 0.075-4.75 mm, and then the excess powder is sieved out to make the light sand.

[0039] (5) The industrial solid waste-based cementitious material, building solid waste-based admixture, construction waste recycled aggregate and light sand are mixed with cement, water-reducing agent and waste slurry in a certain proportion and stirred evenly to obtain low-carbon solid waste-based shield mortar.

[0040] Furthermore, according to embodiments of the present invention, the application of the low-carbon solid waste-based shield tunneling mortar prepared by the aforementioned preparation method in the grouting behind the shield tunnel wall is also provided.

[0041] Beneficial effects: The shield mortar of the present invention has good resistance to water dispersion and bleeding, and can resist the erosion of groundwater; it has a high consolidation rate and low shrinkage, and can fill the gaps at the shield tail well; the setting time is controllable, and it can solidify within a specified time to meet the needs of construction; it has high fluidity and good strength; therefore, the shield mortar of the present invention has good construction performance and good filling performance, and has good promotion and application value in shield grouting construction. Detailed Implementation

[0042] The technical solutions of the present invention will be further described below with reference to the embodiments.

[0043] The preparation method of low-carbon solid waste-based shield tunneling mortar in Examples 1-5 and Comparative Examples 1-3 of the present invention includes the following steps:

[0044] (1) Preparation of industrial solid waste-based cementitious materials: granulated blast furnace slag, steel slag, fly ash, iron tailings and gypsum are dried, mixed evenly in a certain proportion, and then ground to a certain fineness to obtain industrial solid waste-based cementitious materials.

[0045] (2) Preparation of building solid waste-based admixture: Lightweight brick waste residue, concrete waste residue and ceramsite are dried, then crushed to particles with a particle size of 0.075-4.75mm, and then ground to a certain fineness to obtain lightweight brick waste residue powder, recycled micro powder and ceramsite powder. Finally, they are mixed evenly in a certain proportion.

[0046] (3) Preparation of recycled aggregate from construction waste: After removing the steel bars from the waste concrete blocks, the waste concrete blocks are subjected to three-stage crushing: coarse crushing, medium and fine crushing, and fine crushing. The excess powder with a particle size not exceeding 0.075 mm is then screened out until the powder content does not exceed 5%, and the recycled aggregate from construction waste is then prepared.

[0047] (4) Light sand preparation: After drying the waste residue of aerated concrete or foamed concrete, it is subjected to three-stage crushing: coarse crushing, medium and fine crushing and fine crushing. Then, excess powder with a particle size not exceeding 0.075 mm is screened out until the powder content does not exceed 5% to make the light sand.

[0048] (5) The industrial solid waste-based cementitious material, building solid waste-based admixture, construction waste recycled aggregate and light sand are mixed with cement, water-reducing agent and waste slurry in a certain proportion and stirred evenly to obtain low-carbon solid waste-based shield mortar.

[0049] The above preparation steps, in Examples 1-5 and Comparative Examples 1-3, the mass ratio and fineness of each raw material are shown in Tables 1-3.

[0050] Table 1 shows the raw material ratios, fineness (expressed as specific surface area), and other data for each embodiment and comparative example.

[0051]

[0052] Table 2 shows the component proportions of industrial solid waste-based cementitious materials in each embodiment and comparative example.

[0053]

[0054] Table 3 shows the composition ratio and fineness (expressed as specific surface area) of the building solid waste-based admixtures in each embodiment and comparative example.

[0055]

[0056] Explanation of Examples 1-5 and Comparative Examples 1-3

[0057] 1. In the embodiments and comparative examples of the present invention, all raw materials must be accurately weighed according to the mixing ratio. The weighing error of each raw material is shown in Table 4.

[0058] Table 4 Allowable Deviations in Raw Material Measurement

[0059]

[0060] 2. In all the embodiments and comparative examples, the cement used was P·O42.5, with a specific surface area of ​​370 m². 2 / kg; the water-reducing agent is a polycarboxylate high-efficiency water-reducing agent with a water reduction rate of 32%.

[0061] 3. The lightweight brick waste in Examples 1-5 and Comparative Example 2 are as follows:

[0062] Example 1: Waste residue from aerated concrete;

[0063] Example 2: Waste residue from foamed concrete;

[0064] Example 3: Sintered brick waste residue;

[0065] Example 4: A mixture of aerated concrete waste and foamed concrete waste in a 1:1 mass ratio;

[0066] Example 5: A mixture of aerated concrete waste residue, foamed concrete waste residue, and sintered brick waste residue in a 1:1 mass ratio;

[0067] Comparative Example 2: Same as Example 1.

[0068] 4. The raw materials used for the light sand in Examples 1-5 and Comparative Example 1 are as follows:

[0069] Example 1: Waste residue from aerated concrete;

[0070] Example 2: Waste residue from foamed concrete;

[0071] Example 3: Waste residue from aerated concrete;

[0072] Example 4: Waste residue from foamed concrete;

[0073] Example 5: A mixture of aerated concrete waste and foamed concrete waste in a 1:1 mass ratio;

[0074] Comparative Example 1: Same as Example 1.

[0075] 5. The waste slurry refers to the waste slurry generated from washing tank trucks, separating sand and gravel, and washing the mixing tower at a commercial concrete mixing plant. Its concentration (i.e., mass percentage) is 0-20%. In addition, the concentration of waste slurry will affect the working performance of the shield tunneling mortar to a certain extent.

[0076] The application test results of the low-carbon solid waste-based shield tunneling mortar prepared in Examples 1-5 and Comparative Examples 1-3 of this invention are shown in Table 5.

[0077] Table 5. Test results of low-carbon solid waste-based shield tunneling mortar prepared in each embodiment and comparative example.

[0078]

[0079] As can be seen from the test data of the above embodiments and comparative examples, the low-carbon solid waste-based shield tunneling mortar of the present invention has the following advantages:

[0080] (1) High consolidation rate and good construction performance. The stone-setting rate of Examples 1 to 5 is not less than 99%. In contrast, Comparative Example 2 did not add lightweight sand, but increased the proportion of recycled aggregate from construction waste. Accordingly, the stone-setting rate of Comparative Example 2 is only 94%, which is much lower than that of Examples 1 to 5. In addition, the lightweight sand of the present invention, as a particle within the fine aggregate particle size range, can retain a large number of internal pores in the form of through holes. The large number of through holes can store enough water, ensuring the full progress of the hydration reaction. In summary, it shows that the lightweight sand used in the embodiments of the present invention has a certain water storage capacity, which can play a good internal curing role and significantly reduce the shrinkage of the shield mortar, thereby resulting in a high consolidation rate. In addition, the 3-hour consistency loss and 3-hour flowability loss of Examples 1 to 5 are both less than 10 mm. Therefore, the shield mortar of the present invention can maintain good construction performance for a long time.

[0081] (2) It has strong water retention, good resistance to water dispersion and bleeding. The water retention rates of Examples 1-5 are all above 99%, and the segregation degree is less than 10 mm. In contrast, Comparative Example 1 did not add building waste-based admixtures, but increased the proportion of cement. Consequently, the water retention rate of Comparative Example 1 is only 91.6%, which is much lower than that of Examples 1-5. Considering the fineness of the grinding of the building waste-based admixtures, specifically, as shown in Table 1, the specific surface area of ​​the building waste-based admixtures (280-320 m²) is... 2The specific surface area ( / kg) of industrial solid waste-based cementitious materials is smaller than that of industrial solid waste-based cementitious materials (390-440m²). 2 / kg), which is also smaller than the specific surface area of ​​the cement used in this invention (370m²). 2 / kg), and it is known that the specific surface area of ​​light sand within the fine aggregate particle size range should be smaller than that of the admixture obtained after grinding; that is to say, the building solid waste-based admixture of the present invention has a suitable grinding fineness. Within its fineness range, especially the large number of pores (micropores) inside the lightweight brick waste residue from which its main component is derived will neither be retained in the form of through pores (and will not play an internal curing role), nor will they be completely ground down, thus retaining surface roughness, which increases the specific surface area and thus increases the water demand of the material; in summary, it is shown that the building solid waste-based admixture used in the embodiments of the present invention, especially the lightweight brick waste residue powder, has a high water demand, resulting in strong water retention and good anti-water dispersion and anti-bleeding properties.

[0082] (3) The components promote each other and synergistically improve the performance of the low-carbon solid waste-based shield mortar, thereby increasing the effective utilization rate of each component. Comparative Example 3 did not add light sand or building solid waste-based admixtures, resulting in the shield mortar's stone formation rate, water retention rate, and segregation degree being lower than those of Comparative Example 1 and Comparative Example 2, and far lower than those of Examples 1-5. This indicates that the components, especially the light sand and building solid waste-based admixtures, promote each other and synergistically improve the consolidation rate and water retention of the shield mortar.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A low-carbon solid waste-based shield tunneling mortar, characterized in that: The raw materials used in mortar, by mass percentage, include 8-14% industrial solid waste-based cementitious materials, 6-10% cement, 18-22% construction solid waste-based admixtures, 26-30% recycled construction waste aggregates, 10-14% lightweight sand, and 15-20% waste slurry water, with the remainder being water-reducing agents. The raw materials used in industrial solid waste-based cementitious materials, by mass percentage, include 42%-48% granulated blast furnace slag, 38-46% steel slag, 0-8% fly ash, 6-10% iron tailings, and 2-6% industrial by-product gypsum; and their specific surface area is 390-440 m². 2 / kg; Construction solid waste-based admixtures include lightweight brick waste powder, wherein the raw material for the lightweight brick waste powder is at least one of aerated concrete waste, foamed concrete waste, or sintered brick waste, and its specific surface area is 300-340 m². 2 / kg; The raw materials used for lightweight sand are at least one of aerated concrete waste residue and foamed concrete waste residue, and their particle size is not greater than 4.75mm.

2. The low-carbon solid waste-based shield tunneling mortar as described in claim 1, characterized in that: The raw materials used in industrial solid waste-based cementitious materials, by mass percentage, include 44% granulated blast furnace slag, 39% steel slag, 6-8% fly ash, 6-10% iron tailings, and 2-4% industrial by-product gypsum; and their specific surface area is 390-410 m². 2 / kg.

3. The low-carbon solid waste-based shield tunneling mortar as described in claim 1, characterized in that: The raw materials used in industrial solid waste-based cementitious materials, by mass percentage, include 42% granulated blast furnace slag, 46% steel slag, 2-6% fly ash, 6-8% iron tailings, and 2-3% industrial by-product gypsum; and their specific surface area is 390-410 m². 2 / kg.

4. The low-carbon solid waste-based shield tunneling mortar as described in claim 1, characterized in that: The raw materials used in the building solid waste-based admixture, by mass percentage, include 46-52% lightweight brick waste powder, 28-36% recycled micro powder, and 16-26% ceramsite powder; and its specific surface area is 280-320 m². 2 / kg.

5. The low-carbon solid waste-based shield tunneling mortar as described in claim 4, characterized in that: The raw materials used in the building solid waste-based admixture, by weight percentage, include 50% lightweight brick waste powder, 33% recycled micro powder, and 17% ceramsite powder; and its specific surface area is 280 m². 2 / kg.

6. The low-carbon solid waste-based shield tunneling mortar as described in claim 4, characterized in that: The raw material for recycled micro powder is concrete waste, and its specific surface area is 240-280 m². 2 / kg; the specific surface area of ​​ceramsite powder is 300-340m². 2 / kg.

7. The low-carbon solid waste-based shield tunneling mortar as described in claim 1, characterized in that: The raw material used for recycled aggregates from construction waste is waste concrete blocks with a particle size not exceeding 4.75mm and a fineness modulus of 2.3-2.

6.

8. A method for preparing low-carbon solid waste-based shield tunneling mortar as described in any one of claims 1-7, characterized in that, Includes the following steps: (1) Preparation of industrial solid waste-based cementitious materials: After drying the industrial solid waste materials, they are mixed evenly and then ground to a certain fineness to obtain industrial solid waste-based cementitious materials. (2) Preparation of building solid waste-based admixture: Dry the lightweight brick waste powder building solid waste material, then crush it into particles with a particle size of 0.075-4.75mm, then grind it to a certain fineness and mix it evenly. (3) Preparation of recycled aggregate from construction waste: The steel bars in the construction waste are removed, and then crushed to particles with a particle size of 0.075-4.75 mm. The excess powder is then screened out to make the recycled aggregate from construction waste. (4) Preparation of light sand: The raw materials used for light sand are dried, crushed to particles with a particle size of 0.075-4.75 mm, and the excess powder is sieved out to make the light sand; (5) The industrial solid waste-based cementitious material, building solid waste-based admixture, recycled aggregate of construction waste and light sand are mixed with cement, water-reducing agent and waste slurry in a certain proportion and stirred evenly to obtain low-carbon solid waste-based shield mortar.

9. The application of the low-carbon solid waste-based shield tunneling mortar prepared by the preparation method described in claim 8 in the grouting behind the shield tunnel wall.

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