A grouting material for tunnel boring machines and its preparation method

Abstract

This invention relates to the field of building materials technology, and in particular to a shield tunneling grouting material and its preparation method. The shield tunneling grouting material comprises the following raw materials in parts by weight: 80-150 parts ordinary cement, 1-5 parts silica fume, 5-20 parts bentonite, 50-150 parts fly ash, 100-250 parts manufactured sand, 500-750 parts pretreated construction waste separation soil, 0-0.3 parts water-retaining thickener, 0-3 parts water-reducing agent, and 500-650 parts water. The shield tunneling grouting material of this invention uses a large amount of pretreated construction waste separation soil as raw material, reducing the use of natural fine sand and fly ash. This solves the dilemma of resource utilization of such waste soil and also reduces the consumption of natural fine sand and fly ash, resulting in significant resource conservation.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a shield tunneling grouting material and its preparation method. Background Technology

[0002] Construction waste separation soil is a type of construction waste separation soil generated during the pretreatment process of construction waste resource utilization, accounting for 30-40% of the total construction waste. Construction waste separation soil contains waste concrete, waste bricks, and waste mortar, as well as demolition decoration and renovation waste and ordinary soil, etc., and its composition is extremely complex and has low pozzolanic activity, so it is usually disposed of by landfill.

[0003] Shield tunneling grout is a widely used material in shield tunneling projects. It fills the gaps between the tunnel segments and the soil, serving to fill the voids behind the tunnel wall and stabilize the tunnel lining. Typically, shield tunneling grout consists of fine sand, cementing materials, and admixtures.

[0004] Currently, fine sand accounts for more than 60% of shield tunneling grout, and cementitious materials account for more than 30%, resulting in significant consumption of natural resources. As the country increases its efforts in ecological and environmental protection year by year, the use of solid waste to replace natural resources as building materials is an inevitable trend in the construction industry. Summary of the Invention

[0005] This invention provides a method for preparing shield tunneling grout using construction waste separation and soil separation, in order to solve the problem of high consumption of natural resources such as fine sand and cementing materials in existing shield tunneling grouting materials.

[0006] According to a first aspect of the present invention, the present invention provides a shield tunneling grouting material comprising the following raw materials in parts by weight: 80-150 parts of ordinary cement, 1-5 parts of silica fume, 5-20 parts of bentonite, 50-150 parts of fly ash, 100-250 parts of manufactured sand, 500-750 parts of pretreated construction waste separation soil, 0-0.3 parts of water-retaining thickener, 0-3 parts of water-reducing agent, and 500-650 parts of water.

[0007] In the above-mentioned scheme, the shield tunneling grout of this invention uses a large amount of pretreated construction waste separation soil as raw material, reducing the use of natural fine sand and fly ash. This solves the dilemma of resource utilization of the waste soil and also reduces the consumption of natural fine sand and fly ash. The sand and cementitious material (ordinary cement) in the shield tunneling grout of this invention are far lower than the conventional ratios of 60% and 30%, respectively, resulting in significant resource savings. Furthermore, the shield tunneling grout of this invention achieves a good gradation effect by combining the pretreated construction waste separation soil with manufactured sand, ensuring that the strength of the shield tunneling grout meets the standard requirements. Moreover, the shield tunneling grout of this invention rationally limits the amount of each raw material component, allowing for better synergistic effects between the components, ultimately resulting in shield tunneling grout with excellent fluidity, consolidation rate, apparent setting time, initial setting time, and compressive strength, meeting the needs of practical applications.

[0008] Furthermore, the particle size of the pretreated construction waste separation soil meets the following requirements: D50 < 0.05 mm, 0.2 mm ≤ D90 ≤ 0.6 mm, 3.5 ≤ (D90 - D10) / D50 ≤ 7.5, where D10 is the particle size corresponding to a cumulative particle size distribution percentage of 10%, D50 is the particle size corresponding to a cumulative particle size distribution percentage of 50%, and D90 is the particle size corresponding to a cumulative particle size distribution percentage of 90%.

[0009] In the above scheme, the particle size of the pretreated construction waste separation soil was reasonably selected. The purpose includes: (1) to homogenize the components of the finely ground construction waste separation soil; (2) to increase the specific surface area, which plays a role in nucleation and promoting the hydration of cementitious materials; and (3) to form a better gradation effect with the aggregates and incompletely hydrated cement particles in the shield grouting material, filling the pores of the shield grouting material and ensuring that the strength of the shield grouting material meets the standard requirements. If the particle size and pore size distribution of the construction waste separation soil cannot meet the above requirements, it will affect one or more of the performance characteristics of the shield grouting material, such as compressive strength, fluidity, and degree of consolidation, and thus make it unable to meet the use standard requirements.

[0010] Further, the particle size of the pretreated construction waste separation soil meets the following requirements: 0.02mm≤D50≤0.03mm, 0.2mm≤D90≤0.3mm, 7.0≤(D90-D10) / D50≤7.25; preferably, the particle size of the pretreated construction waste separation soil meets the following requirements: D50=0.027mm, D90=0.2mm, (D90-D10) / D50=7.16.

[0011] Further, by weight percentage, the mass percentage content of each substance in the pretreated construction waste separated slag is as follows: SiO2: 58.5-62.66%, CaO: 11.56-12.06%, Al2O3: 12.2-12.7%, Fe2O3: 3.66-3.93%, Na2O: 2.31-2.79%, K2O: 2.35-2.55%, MgO: 3.22-4.26%, SO3: 0.88-1.19%, TiO2: 0.46-0.67%, BaO: 0.05-0.22%, Cl: 0-0.08%, and water: 0.97-1.13%.

[0012] The above scheme limits the composition of the pretreated construction waste separation soil, which has a certain hydration activity and a good fine aggregate gradation effect, thereby replacing part of the fly ash and natural fine sand.

[0013] Furthermore, the ordinary cement includes one or more of type I silicate cement, type II silicate cement, or ordinary silicate cement.

[0014] Furthermore, the fly ash is classified as Grade I or Grade II.

[0015] Furthermore, the particle size of the manufactured sand is <0.6mm.

[0016] Furthermore, the water-retaining thickener is a cellulose ether-based water-retaining thickener.

[0017] Furthermore, the water-reducing agent is a polycarboxylate water-reducing agent.

[0018] The above scheme, through the rational selection of the type of ordinary cement, the grade of fly ash, the particle size of manufactured sand, the type of water-retaining thickener and the type of water-reducing agent, enables the components to achieve better synergistic effects and makes the resulting shield grouting material perform better.

[0019] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned shield grouting material, comprising the following steps:

[0020] A combined pretreatment method of low-temperature heat treatment and mechanical grinding was adopted to pretreat the construction waste separation soil, resulting in pretreated construction waste separation soil;

[0021] Weigh out 80-150 parts of ordinary cement, 1-5 parts of silica fume, 5-20 parts of bentonite, 50-150 parts of fly ash, 100-250 parts of manufactured sand, 500-750 parts of pretreated construction waste separation soil, 0-0.3 parts of water-retaining thickener, and 0-3 parts of water-reducing agent according to the specified proportions, mix them evenly, then add water and stir continuously for 2-5 minutes to obtain the shield tunneling grouting material.

[0022] In the above scheme, the preparation method of the shield grouting material of the present invention first adopts a composite pretreatment method of low-temperature heat treatment and mechanical grinding to pretreat the construction waste separation soil to obtain pretreated construction waste separation soil. The purpose of low-temperature heat treatment is to remove free water, organic matter, etc. from the construction waste separation soil, and to generate active substances, so that the moisture content of the construction waste separation soil is maintained below 1%, which is beneficial to subsequent grinding and can also obtain construction waste separation soil with activation properties, thereby improving the performance of the shield grouting material. The purpose of mechanical grinding is to grind the heat-treated construction waste separation soil to a certain standard using a ball mill, so that the components of the pretreated construction waste separation soil are more homogeneous, have a more suitable specific surface area, and better play the role of nucleation and promoting the hydration of cementitious materials. It can form a better gradation effect with aggregates and incompletely hydrated cement particles in the shield grouting material, fill the pores of the shield grouting material, and ensure that the strength of the shield grouting material meets the standard requirements. The pretreatment method of construction waste separation soil of the present invention is simple. The method for preparing shield grouting material of the present invention involves mixing pretreated construction waste slag with ordinary cement, silica fume, bentonite, fly ash, manufactured sand, water-retaining thickener and water-reducing agent, and then adding water and stirring continuously for 2-5 minutes to obtain a uniform shield grouting material with excellent performance.

[0023] Furthermore, the low-temperature heat treatment is performed at a temperature of 100℃-300℃ for a time of 60-120 minutes.

[0024] In the above-described scheme, by reasonably limiting the temperature and time of the low-temperature heat treatment, it is possible to ensure the removal of free water and organic matter from the construction waste and slag, thereby generating more active substances, which is beneficial to improving the overall performance of the subsequent shield tunneling grouting material. The low-temperature heat treatment of this invention has a low temperature and significant energy-saving effect.

[0025] This invention discloses a shield tunneling grouting material that utilizes a large amount of pre-treated construction waste separation soil as raw material, reducing the use of natural fine sand and fly ash. This not only solves the dilemma of waste soil resource utilization but also reduces the consumption of natural fine sand and fly ash. The sand and cementitious material (ordinary cement) in this invention's shield tunneling grouting material are significantly lower than the conventional ratios of 60% and 30%, respectively, resulting in significant resource savings. Furthermore, this invention's shield tunneling grouting material achieves a good gradation effect by combining pre-treated construction waste separation soil with manufactured sand, ensuring that the strength of the shield tunneling grouting material meets the standard requirements.

[0026] The present invention provides a simple method for preparing shield tunneling grout, which involves a low heat treatment temperature and significant energy-saving effect. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a particle size distribution diagram of pretreated construction waste separated soil in shield tunnel grouting material provided in Embodiment 1 of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] In the following examples and comparative examples, the mass percentage of each substance in the separated construction waste slag is as follows: SiO2: 52.21-56.46%, CaO: 8.41-11.78%, Al2O3: 8.99-11.34%, Fe2O3: 3.29-3.51%, Na2O: 2.08-2.49%, K2O: 1.11-2.37%, MgO: 2.91-3.81%, SO3: 0.79-1.07%, TiO2: 0.46-0.49%, BaO: 0.05-0.19%, Cl: 0-0.07%, and water: 11.76-13.9%.

[0031] Fly ash, manufactured sand, bentonite, silica fume, water-retaining thickener, and water-reducing agent are all commercially available products.

[0032] Examples 1-3

[0033] This embodiment provides a shield tunneling grouting material, the raw material composition of which is shown in Table 1 below by weight.

[0034] Table 1

[0035]

[0036] The particle size distribution diagram of the pretreated construction waste separated slag is shown below. Figure 1As shown, the particle size satisfies: D50 = 0.027 mm, D90 = 0.2 mm, and D10, D50 and D90 satisfy: (D90-D10) / D50 = 7.15, where D10 is the particle size corresponding to the cumulative particle size distribution percentage of 10%, D50 is the particle size corresponding to the cumulative particle size distribution percentage of 50%, and D90 is the particle size corresponding to the cumulative particle size distribution percentage of 90%. By weight percentage, the pretreated construction waste separated slag contains: SiO2 (60.93%), CaO (11.76%), Al2O3 (12.24%), Fe2O3 (3.7%), Na2O (2.48%), K2O (2.37%), MgO (3.91%), SO3 (0.88%), TiO2 (0.5%), BaO (0.2%), Cl (0.02%), and water 1.01%.

[0037] The fly ash is classified as Grade II. The particle size of the manufactured sand is <0.6mm. The water-retaining thickener is a cellulose ether-based water-retaining thickener. The water-reducing agent is a polycarboxylate water-reducing agent.

[0038] The above-mentioned method for preparing shield tunneling grout includes the following steps:

[0039] A combined pretreatment method of low-temperature heat treatment and mechanical grinding was adopted to pretreat the construction waste separation soil to obtain pretreated construction waste separation soil; the low-temperature heat treatment temperature was 200℃ and the time was 60min, and the mechanical grinding was carried out by ball milling to grind to meet the above-mentioned particle size requirements.

[0040] Weigh out ordinary cement, silica fume, bentonite, fly ash, manufactured sand, pretreated construction waste separation soil, water-retaining thickener and water-reducing agent according to the proportions in Table 1, mix them evenly, then add water and stir continuously for 3 minutes to obtain shield grouting material.

[0041] Examples 4-6

[0042] This embodiment provides a shield tunneling grouting material, which differs from Embodiment 1 in that the particle size distribution of the pretreated construction waste separation soil is different, as shown in Table 2 below.

[0043] Table 2

[0044]

[0045] Comparative Example 1

[0046] This comparative example provides a shield tunneling grouting material, which differs from Example 1 in that an equal amount of untreated construction waste separation soil is used instead of pretreated construction waste separation soil. Because untreated construction waste separation soil contains a large number of particles with a diameter much larger than 5mm, when used as raw material, these large particles settle directly to the bottom of the container after stirring is stopped, making it impossible to prepare a qualified shield tunneling grouting material.

[0047] Comparative Example 2

[0048] This comparative example provides a shield tunneling grouting material, which differs from Example 1 in that it only uses a mechanical grinding method to pre-treat the construction waste separation soil.

[0049] Table 2

[0050]

[0051]

[0052] As can be seen from the experimental results in Table 2, the shield grouting material of this invention uses pretreated construction waste separation soil as raw material. The resulting shield grouting material meets the standard requirements for use. Furthermore, the use of a large amount of pretreated construction waste separation soil as raw material reduces the use of natural fine sand and fly ash, thus solving the dilemma of resource utilization of this waste soil and reducing the consumption of natural fine sand and fly ash. In addition, the particle size and particle size distribution of the pretreated construction waste separation soil are crucial. Selecting pretreated construction waste separation soil with appropriate particle size and distribution is beneficial to improving the overall performance of the shield grouting material. The pretreatment of construction waste separation soil using a composite pretreatment method of low-temperature heat treatment and mechanical grinding results in pretreated construction waste separation soil with superior performance, which is beneficial to improving the overall performance of the shield grouting material.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A shield tunneling grouting material, characterized in that, The raw materials include the following parts by weight: 80-150 parts ordinary cement, 1-5 parts silica fume, 5-20 parts bentonite, 50-150 parts fly ash, 100-250 parts manufactured sand, 500-750 parts pretreated construction waste separation soil, 0-0.3 parts water-retaining thickener, 0-3 parts water-reducing agent, and 500-650 parts water; The particle size of the pretreated construction waste separation soil meets the following requirements: D50 < 0.05 mm, 0.2 mm ≤ D90 ≤ 0.6 mm, 3.5 ≤ (D90 - D10) / D50 ≤ 7.5, where D10 is the particle size corresponding to a cumulative particle size distribution percentage of 10%, D50 is the particle size corresponding to a cumulative particle size distribution percentage of 50%, and D90 is the particle size corresponding to a cumulative particle size distribution percentage of 90%.

2. The shield tunneling grouting material according to claim 1, characterized in that, The particle size of the pretreated construction waste separated slag meets the following requirements: 0.02mm≤D50≤0.03mm, 0.2mm≤D90≤0.3mm, and 7.0≤(D90-D10) / D50≤7.

25.

3. The shield tunneling grouting material according to claim 2, characterized in that, The particle size of the pretreated construction waste separated soil meets the following requirements: D50 = 0.027 mm, D90 = 0.2 mm, (D90-D10) / D50 = 7.

16.

4. The shield grouting material according to claim 1, characterized in that, The mass percentages of each substance in the pretreated construction waste slag are as follows (by weight): SiO2: 58.5-62.66%, CaO: 11.56-12.06%, Al2O3: 12.2-12.7%, Fe2O3: 3.66-3.93%, Na2O: 2.31-2.79%, K2O: 2.35-2.55%, MgO: 3.22-4.26%, SO3: 0.88-1.19%, TiO2: 0.46-0.67%, BaO: 0.05-0.22%, Cl: 0-0.08%, and water: 0.97-1.13%, with the sum of the mass percentages of each substance being 100%.

5. The shield grouting material according to claim 1, characterized in that, The ordinary cement includes one or more of type I silicate cement, type II silicate cement, or ordinary silicate cement; and / or, the fly ash is grade I or grade II.

6. The shield tunneling grouting material according to claim 1, characterized in that, The particle size of the manufactured sand is <0.6mm.

7. The shield tunneling grouting material according to claim 1, characterized in that, The water-retaining and thickening agent is a cellulose ether-based water-retaining and thickening agent.

8. The shield tunneling grouting material according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent.

9. The method for preparing the shield tunneling grouting material according to any one of claims 1-8, characterized in that, Includes the following steps: A combined pretreatment method of low-temperature heat treatment and mechanical grinding was adopted to pretreat the construction waste separation soil, resulting in pretreated construction waste separation soil; Weigh out 80-150 parts of ordinary cement, 1-5 parts of silica fume, 5-20 parts of bentonite, 50-150 parts of fly ash, 100-250 parts of manufactured sand, 500-750 parts of pretreated construction waste separation soil, 0-0.3 parts of water-retaining thickener, and 0-3 parts of water-reducing agent according to the specified proportions, mix them evenly, then add water and stir continuously for 2-5 minutes to obtain the shield tunneling grouting material.

10. The preparation method according to claim 9, characterized in that, The low-temperature heat treatment is performed at a temperature of 100℃-300℃ for a time of 60-120 minutes.

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