Multi-solid-waste shield tunnel synchronous grouting material and preparation method thereof

Abstract

The invention discloses a multi-solid-waste shield tunnel synchronous grouting material and a preparation method thereof, the multi-solid-waste shield tunnel synchronous grouting material comprises an alkali-activated main material, an activator, engineering residue soil and water; the mass ratio of the alkali-activated main material to the engineering residue soil is (0.3-0.4): 1, the mass ratio of the water to the engineering residue soil is (0.4-0.5): 1, and the mass ratio of the exciting agent to the alkali-activated main material is (0.12-0.2): 1. According to the invention, an alkali excitation process and engineering residue soil treatment are combined, the engineering residue soil and industrial solid waste are treated at the same time, and the effect of treating waste with waste can be achieved while the green and environment-friendly synchronous grouting material is prepared.

Description

Technical Field

[0001] The invention relates to the technical field of grouting materials, and in particular to a multi-solid waste shield tunnel synchronous grouting material and a preparation method thereof. Background Art

[0002] In recent years, urban subway construction has developed rapidly, and the scale of urban subways has expanded rapidly, facing more and more complex and harsh geological conditions. At present, urban subway construction mainly adopts shield construction, which can overcome the influence of complex geological conditions and has the advantages of fast construction speed, good safety and strong adaptability.

[0003] The shield construction of subway mainly uses shield machine for excavation construction. Since the diameter of the shield machine shell is larger than the outer diameter of the segment, when the shield machine moves forward and detaches from the segment, a circular over-excavation gap, namely the shield tail gap, will be formed between the segment and the soil layer, making the soil layer around the tunnel temporarily empty. The functions of synchronous grouting behind the wall include: 1) filling the gap early to prevent stratum deformation; 2) fixing the position of the segment lining; 3) ensuring the compactness of the shield tail gap so that the segment is evenly stressed; 4) as the first line of defense for lining waterproofing, providing long-term, stable and effective waterproofing function; 5) as a reinforcement layer of the tunnel segment structure, providing a certain bearing capacity.

[0004] At present, the traditional single-liquid grouting materials used in shield construction have problems such as low early strength, poor stability, easy segregation and stratification, poor water dispersion and durability, while the traditional cement-water glass two-liquid grouting materials are susceptible to erosion and damage in groundwater due to their poor structural stability and resistance to groundwater dissolution of hydration products, resulting in serious strength loss. Therefore, it is urgent to develop a new type of synchronous grouting fluid to improve the effect of shield construction.

[0005] A new type of solid waste-based synchronous grouting material is developed using a variety of industrial solid waste materials (such as slag, fly ash, coal gangue, carbide slag, steel slag, etc.) to meet the requirements of synchronous grouting in shield construction. It can also greatly reduce the stockpile of industrial solid waste, reduce carbon emissions, and lower project costs. Summary of the invention

[0006] The purpose of this application is to solve the problems existing in the prior art, make full use of different types of industrial solid wastes, and provide a multi-solid waste shield tunnel synchronous grouting material and a preparation method thereof.

[0007] The technical solution adopted to achieve the purpose of this application is:

[0008] A multi-solid waste shield tunnel synchronous grouting material, comprising an alkali-activated main material, an activator, engineering slag and water;

[0009] The mass ratio of the alkali-activated main material to the engineering slag is 0.3-0.4:1, the mass ratio of the water to the engineering slag is 0.4-0.5:1, and the mass ratio of the activator to the alkali-activated main material is 0.12-0.2:1.

[0010] In the above technical scheme, the main materials of the alkali-activated main material include slag powder, fly ash, coal gangue, carbide slag and steel slag powder. The slag powder content of the alkali-activated main material is 20% to 25%, the fly ash content is 20% to 25%, the coal gangue content is 8% to 15%, the carbide slag content is 5% to 15%, and the steel slag powder content is 12% to 30%.

[0011] In the above technical solution, the specific surface area of ​​the slag powder is 400-450m 2 / kg, density ≥2.8g / cm 3 The particle size of the slag powder is ≤0.75 mm, the loss on ignition of the slag powder is ≤1.0%, and the water content is ≤1.0%.

[0012] In the above technical solution, the activator includes sodium hydroxide and sodium silicate, and the mass ratio of sodium hydroxide to sodium silicate is 1:1.

[0013] In the above technical solution, the engineering slag has a particle size of ≤5.0mm and a plasticity index of I p Silty clay or clay with a soil density of ≥8.0.

[0014] A method for preparing a synchronous grouting material for a multi-solid waste shield tunnel comprises the following steps:

[0015] Step 1, drying the construction waste in an oven at 105°C, crushing it and passing it through a 5mm sieve for later use;

[0016] Step 2, drying slag powder, fly ash, coal gangue, carbide slag, and steel slag powder, crushing them with a crusher, and then passing through a 0.75 mm sieve for later use;

[0017] Step 3, respectively weighing 1000g of sieved engineering slag, 100g of slag powder, 100g of fly ash, 40g of coal gangue, 25g of carbide slag, and 135g of steel slag powder, placing them in a cement mortar mixer and stirring for 5min to mix the powders evenly, adding 450g of water to the evenly mixed powders and continuing to stir for 2min, that is, the mass ratio of the alkali-activated main material to the engineering slag is 0.4:1, the mass ratio of water to the engineering slag is 0.45:1, and the mass ratio of the activator to the alkali-activated main material is 0.15:1;

[0018] Step 4, continue to add 30g of sodium hydroxide and 30g of sodium silicate and continue stirring for 2min to obtain the required synchronous grouting material.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. The present invention adopts an alkali activation method to mix different types of industrial solid waste and construction slag to prepare synchronous grouting materials, which can greatly reduce the amount of building materials such as cement and fine sand, reduce production costs, and at the same time utilize construction slag to effectively reduce production carbon emissions.

[0021] 2. The present invention combines the alkali activation process with the treatment of engineering slag, and simultaneously treats engineering slag and industrial solid waste. While preparing green and environmentally friendly synchronous grouting materials, it can also achieve the effect of "treating waste with waste".

[0022] 3. The present invention uses a variety of industrial solid wastes as the main materials for alkali activation. Slag, coal gangue, carbide slag, and steel slag are all industrial solid wastes produced by the steel and power industries. The annual output is huge, and stacking and landfilling will cause environmental pollution and huge processing costs. Effective processing methods for different types of solid wastes are obtained. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with specific embodiments.

[0024] Example 1

[0025] A multi-solid waste shield tunnel synchronous grouting material, comprising an alkali-activated main material, an activator, engineering slag and water, wherein:

[0026] The main materials of the alkali-activated main material include industrial solid wastes such as slag powder, fly ash, coal gangue, carbide slag and steel slag powder; the slag powder content of the alkali-activated main material is 20% to 25% (mass), the fly ash content is 20% to 25% (mass), the coal gangue content is 8% to 15% (mass), the carbide slag content is 5% to 15% (mass), and the steel slag powder content is 12% to 30% (mass); the specific surface area of ​​the slag powder is 400 to 450 m 2 / kg, density ≥2.8g / cm 3 The particle size of the slag powder is ≤0.75 mm, the loss on ignition of the slag powder is ≤1.0%, and the water content is ≤1.0%.

[0027] The activator includes sodium hydroxide and sodium silicate, and the mass ratio of the sodium hydroxide to the sodium silicate is 1:1.

[0028] The engineering slag has a particle size of ≤5.0 mm and a plasticity index of I p Silty clay or clay with a soil density of ≥8.0.

[0029] The mass ratio of the alkali-activated main material to the engineering slag is 0.3-0.4:1, the mass ratio of the water to the engineering slag is 0.4-0.5:1, and the mass ratio of the activator to the alkali-activated main material is 0.12-0.2:1.

[0030] The raw materials used in this example are all commercially available unless otherwise specified.

[0031] The multi-solid waste shield tunnel synchronous grouting materials in this embodiment adopt TCECS563-2018 "Technical Code for Application of Synchronous Grouting Materials for Shield Tunnels", JGJT70-2009 "Test Methods for Masonry Mortar" and TCECS563-2018 "Technical Code for Application of Synchronous Grouting Materials for Shield Tunnels" to test the working performance indicators of the grouting fluid. The various working performance indicators of the synchronous grouting fluid should meet the requirements shown in Table 1.

[0032] Table 1 Performance index of synchronous grouting fluid in multi-solid waste shield tunnel

[0033]

[0034] In this embodiment, the mass ratio of the alkali-activated main material to the construction waste is defined as the mortar ratio, the mass ratio of water to the construction waste is defined as the water-cement ratio, and the mass ratio of the activator to the alkali-activated main material is defined as the activator dosage.

[0035] A method for preparing a synchronous grouting material for a multi-solid waste shield tunnel comprises the following steps:

[0036] Step 1: Dry the construction waste in an oven at 105°C, crush it and pass it through a 5mm sieve for later use.

[0037] Step 2, drying the slag powder, fly ash, coal gangue, carbide slag and steel slag powder, crushing them with a crusher and then passing them through a 0.75 mm sieve for later use.

[0038] Step 3, respectively weigh 1000g of sieved engineering slag, 100g of slag powder, 100g of fly ash, 40g of coal gangue, 25g of carbide slag, and 135g of steel slag powder, place them in a cement mortar mixer and stir for 5 minutes to mix the powders evenly, add 450g of water to the evenly mixed powders and continue stirring for 2 minutes, that is, the mass ratio of alkali-activated main material to engineering slag (mortar ratio) is 0.4:1, the mass ratio of water to engineering slag is (water-cement ratio) 0.45:1, and the mass ratio of activator to alkali-activated main material (activator dosage) is 0.15:1.

[0039] Step 4, continue to add 30g of sodium hydroxide and 30g of sodium silicate and continue stirring for 2min to obtain the required synchronous grouting material.

[0040] The material proportions of the multi-solid waste shield tunnel synchronous grouting material of this embodiment are shown in Table 2.

[0041] Table 2 Material ratio of multi-solid waste shield tunnel synchronous grouting material in this embodiment

[0042]

[0043] Example 2

[0044] Based on Example 1, the water-cement ratio of the synchronous grouting material for the multi-solid waste shield tunnel was adjusted from 0.45 to 0.55.

[0045] Example 3

[0046] Based on Example 1-2, the water-cement ratio of the synchronous grouting material for the multi-solid waste shield tunnel was adjusted from 0.45 to 0.65.

[0047] The fluidity, 3h water bleeding rate, setting time, 3d compressive strength and 28d compressive strength tests of the synchronous grouting materials of Example 1, Example 2 and Example 3 were respectively carried out according to the specifications. The comparative results of Example 1, Example 2 and Example 3 are shown in Table 3.

[0048] Table 3 Comparison results of Example 1, Example 2 and Example 3

[0049]

[0050] As can be seen from Table 3, the adjustment of the water-cement ratio has a significant effect on the performance of the synchronous grouting material. From the comparison of the results of Example 1, Example 2 and Example 3, it can be seen that too much mixing water increases the distance between the particles, making it difficult to cement, and at the same time reduces the alkalinity in the alkali-activated system, reducing the reaction rate. Therefore, reducing the water-cement ratio will make the fluidity of the grouting material worse, and increasing the water-cement ratio will cause the material to coagulate too slowly, exude more water, and reduce the compressive strength of the material.

[0051] Example 4

[0052] Based on Example 1, the mortar-sand ratio of the synchronous grouting material for the multi-solid waste shield tunnel was adjusted from 0.4:1 to 0.5:1.

[0053] Example 5

[0054] On the basis of Example 1 and Example 4, the mortar-sand ratio of the synchronous grouting material for the multi-solid waste shield tunnel was adjusted from 0.4:1 to 0.6:1.

[0055] The fluidity, 3h water bleeding rate, setting time, 3d compressive strength and 28d compressive strength tests of the synchronous grouting materials of Example 1, Example 4 and Example 5 were respectively carried out according to the specifications. The comparative results of Example 1, Example 4 and Example 5 are shown in Table 4.

[0056] Table 4 Comparison results of Example 1, Example 4 and Example 5

[0057]

[0058] It can be seen from Table 4 that the adjustment of the mortar-sand ratio has a significant effect on the performance of the synchronous grouting material. From the comparison results of Example 1, Example 4 and Example 5, it can be seen that the increase in the amount of cementitious material in Example 4 relative to Example 1 leads to a decrease in the fluidity of the slurry, a shortened setting time and an increase in the strength. This is mainly due to the fact that by increasing the amount of cementitious material, the amount of gels such as CSH and ettringite (Aft) generated by the alkali-induced reaction increases, which strengthens the cementation of soil aggregates and the filling of pores by ettringite.

[0059] Example 6

[0060] On the basis of Example 1, the activator dosage of the synchronous grouting material of the multi-solid waste shield tunnel was adjusted from 0.15:1 to 0.20:1.

[0061] Example 7

[0062] On the basis of Example 1 and Example 6, the activator dosage of the synchronous grouting material of the multi-solid waste shield tunnel was adjusted from 0.15:1 to 0.25:1.

[0063] The fluidity, 3h water bleeding rate, setting time, 3d compressive strength and 28d compressive strength tests of the synchronous grouting materials of Example 1, Example 6 and Example 7 were respectively carried out according to the specifications. The comparative results of Example 1, Example 6 and Example 7 are shown in Table 5.

[0064] Table 5 Comparison results of Example 1, Example 6 and Example 7

[0065]

[0066] It can be seen from Table 5 that adjusting the activator dosage has a significant effect on the performance of the synchronous grouting material. By comparing Example 1, Example 6 and Example 7, it can be found that increasing the activator dosage has a small effect on the fluidity, 3h water bleeding rate and setting time of the slurry, but a greater effect on the compressive strength. Analysis of the reasons: Increasing the activator dosage will increase the content of the generated gel and calcium aluminate, and improve the strength of the slurry.

[0067] In summary, the present invention discloses a multi-solid waste shield tunnel synchronous grouting material and a preparation method thereof. The alkali excitation method is used to mix different types of industrial solid waste and engineering slag to prepare synchronous grouting materials, which can greatly reduce the amount of building materials such as cement and fine sand, reduce production costs, and use engineering slag to effectively reduce production carbon emissions. The present invention adopts an alkali excitation process to prepare the synchronous grouting liquid for the shield tunnel, which can consume a large amount of different types of industrial solid waste and engineering slag, prepare green and environmentally friendly solid waste-based synchronous grouting materials, and achieve the purpose of "turning waste into treasure".

[0068] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multi-solid waste shield tunnel synchronous grouting material, characterized in that: Including alkali activated main material, activator, engineering slag and water; The mass ratio of the alkali-activated main material to the engineering slag is 0.3-0.4:1, the mass ratio of the water to the engineering slag is 0.4-0.5:1, and the mass ratio of the activator to the alkali-activated main material is 0.12-0.2:

1.

2. The multi-solid waste shield tunnel synchronous grouting material according to claim 1 is characterized in that: The main materials of the alkali-activated main material include slag powder, fly ash, coal gangue, carbide slag and steel slag powder. The slag powder content of the alkali-activated main material is 20% to 25%, the fly ash content is 20% to 25%, the coal gangue content is 8% to 15%, the carbide slag content is 5% to 15%, and the steel slag powder content is 12% to 30%.

3. The multi-solid waste shield tunnel synchronous grouting material according to claim 1, characterized in that: The specific surface area of ​​the slag powder is 400-450m 2 / kg, density ≥2.8g / cm 3 The particle size of the slag powder is ≤0.75 mm, the loss on ignition of the slag powder is ≤1.0%, and the water content is ≤1.0%.

4. The multi-solid waste shield tunnel synchronous grouting material according to claim 1, characterized in that: The activator includes sodium hydroxide and sodium silicate, and the mass ratio of the sodium hydroxide to the sodium silicate is 1:

1.

5. The multi-solid waste shield tunnel synchronous grouting material according to claim 1, characterized in that: The engineering slag has a particle size of ≤5.0 mm and a plasticity index of I p Silty clay or clay with a soil density of ≥8.

0.

6. A method for preparing a multi-solid waste shield tunnel synchronous grouting material as claimed in claim 1, characterized in that: The following steps are involved: Step 1, drying the construction waste in an oven at 105°C, crushing it and passing it through a 5mm sieve for later use; Step 2, drying slag powder, fly ash, coal gangue, carbide slag, and steel slag powder, crushing them with a crusher, and then passing through a 0.75 mm sieve for standby use; Step 3, respectively weighing 1000g of sieved engineering slag, 100g of slag powder, 100g of fly ash, 40g of coal gangue, 25g of carbide slag, and 135g of steel slag powder, placing them in a cement mortar mixer and stirring for 5min to mix the powders evenly, adding 450g of water to the evenly mixed powders and continuing to stir for 2min, that is, the mass ratio of the alkali-activated main material to the engineering slag is 0.4:1, the mass ratio of water to the engineering slag is 0.45:1, and the mass ratio of the activator to the alkali-activated main material is 0.15:1; Step 4, continue to add 30g of sodium hydroxide and 30g of sodium silicate and continue stirring for 2min to obtain the required synchronous grouting material.

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