Shield wall backfilling grouting slurry and preparation method thereof

Abstract

The application discloses a shield wall post-grouting slurry, and relates to the technical fields of shield grouting and high polymer materials.The shield wall post-grouting slurry is composed of 15-20 parts of solidified cementation additive, 80-90 parts of slag and 78-107 parts of water by weight; the solidified cementation additive is composed of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyanediamine and silicon powder; the shield wall post-grouting slurry has good flowability before grouting, strong grouting property, high strength after grouting, good waterproof property, strong temperature resistance and strong acid and alkali corrosion resistance, and can meet the requirements of shield wall post-grouting; the solidified cementation additive forms insoluble and infusible high polymer with three-dimensional network structure, has excellent insulation property, mechanical property and chemical stability, can accelerate the solidification of the slurry, and can improve the overall strength, compression resistance and corrosion resistance of the slurry after grouting.

Description

Technical Field

[0001] This invention relates to the fields of shield tunneling grouting and polymer materials technology, specifically a shield tunneling back wall grouting slurry and its preparation method. Background Technology

[0002] During the tunnel boring machine (TBM) construction process, after the tunnel segments are installed, the tail shield gradually detaches from the tunnel segments as the TBM advances. At this time, the tunnel segments are in an unsupported state, which can lead to misalignment, rock collapse, ground subsidence, or even stratum collapse. Therefore, grouting is required during the TBM tunneling process.

[0003] Grouting slurry plays four basic roles in shield tunneling: First, it controls the loosening of the strata around the shield and prevents large strata displacement or collapse; second, it serves as a waterproofing system to prevent groundwater from seeping into the tunnel; third, it supports the tunnel segments, allowing the hydraulic cylinder thrust acting on the segments to be smoothly transmitted to the strata; and fourth, it serves as a reinforcing layer of the tunnel lining structure, protecting the tunnel.

[0004] Existing grouting materials can be divided into single-component grouts and two-component grouts. Single-component grouts are mainly composed of sand, cement, water, bentonite, etc., combined with other auxiliary materials. Two-component grouts are composed of grout A (ice mud, water, clay or bentonite, etc.) and curing agent grout B. The main component of single-component grout is mortar, which has high viscosity, poor fluidity, and high strength after grouting. Two-component grouts do not contain mortar, have low viscosity, good fluidity, but relatively poor strength. It can be seen that the grouts used for wall grouting on the market generally have a contradictory problem between injectability and curing strength. High injectability results in low strength, and high strength results in poor injectability. This is because the strength of ordinary grouts is generally inversely proportional to the water content, while the viscosity of grout is directly proportional to the water content. However, the grout required in shield tunneling construction has requirements for injectability during transportation, requiring high fluidity before grouting, while the grout has requirements for strength after injection, requiring an instantaneous increase in strength to improve the waterproof performance and wall grouting strength.

[0005] Therefore, there is an urgent need to develop a grout that meets the requirements of injectability and high fluidity before grouting, as well as high waterproof performance and high strength after grouting, in order to meet the needs of grouting behind the shield wall. Summary of the Invention

[0006] To address the problem that existing shield wall grouting slurries cannot simultaneously meet the requirements for injectability and grouting strength, the purpose of this invention is to provide a shield wall grouting slurry and its preparation method.

[0007] To achieve the above objectives, the present invention employs the following technical solution: A shield tunnel wall backfill grout, by weight, is composed of the following raw materials: 15-20 parts of curing binder, 80-90 parts of slag and soil, and 78-107 parts of water; wherein the curing binder is composed of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide and silica powder.

[0008] Preferably, the inorganic acid is sulfuric acid or hydrochloric acid with a mass concentration of 30-40%.

[0009] Preferably, the mass ratio of sebacic dihydrazide, inorganic acid, xanthan gum, dicyandiamide and silicon phosphate powder is 30~35:2~3:35~40:20~30:5~10.

[0010] Preferably, the grouting fluid behind the shield wall is composed of the following raw materials in parts by weight: 16 parts of curing binder, 85 parts of slag and soil and 96 parts of water.

[0011] Preferably, the slag is construction slag from the construction site.

[0012] Preferably, the mass ratio of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide and silicon phosphate powder is 32:2.5:36:24:8.

[0013] Preferably, the mass of water is 92-97% of the total mass of the solidifying binder and the slag.

[0014] Preferably, the molar ratio of SiO2 / P2O5 in the silicon phosphate powder is 1.2 to 2.5.

[0015] The present invention also includes a method for preparing a grouting slurry behind the shield wall, wherein 15-20 parts of a curing binder, 80-90 parts of slag and soil and 78-107 parts of water are mixed evenly by weight to obtain the grouting slurry behind the shield wall.

[0016] Preferably, the preparation process of the curing binder includes the following steps: Sebacic acid dihydrazide, inorganic acid, xanthan gum, and dicyandiamide are placed in a mixing device and stirred for 10-15 minutes. After mixing evenly, the mixture is allowed to stand for 7-10 minutes. Then, silicon phosphate powder is added and stirred for 10-15 minutes. After mixing evenly, the mixture is allowed to stand for 7-10 minutes to obtain the curing adhesive additive.

[0017] The present invention has the following advantages over the prior art: The shield tunnel wall backfill grout of this invention exhibits good fluidity and injectability before grouting, and high strength, good waterproofing, strong temperature resistance, and strong acid and alkali corrosion resistance after grouting, thus meeting the requirements for shield tunnel wall backfill grouting. This invention obtains the grout by mixing a curing binder, slag, and water. First, sebacic acid dihydrazide in the curing binder generates hydrazine salt under the catalysis of inorganic acid. The sebacic acid dihydrazide salt then undergoes a cross-linking reaction under dicyandiamide activation, forming an insoluble and infusible polymer with a three-dimensional network structure. This polymer possesses excellent insulation properties, mechanical properties, and chemical stability, accelerating grout solidification and improving the overall strength, compressive strength, and corrosion resistance of the grout after grouting. The silica powder in the curing binder effectively improves the strength, waterproofing, acid and alkali corrosion resistance, and stability of the grout, while ensuring that the grout has a certain degree of fluidity and injectability before grouting.

[0018] The shield tunnel wall backfill grout of the present invention is obtained by using on-site engineering waste soil as raw material, adding solidifying binder and water and mixing. The grout has strong injectability and fluidity, can be used with ordinary grouting machines, has low requirements for grouting equipment, and greatly improves the application range of grout. Detailed Implementation

[0019] The purpose of this invention is to provide a grout for backfilling tunnel walls and its preparation method. The invention will be further described below with reference to specific embodiments.

[0020] The slag used in the following examples are all ordinary soils that can be obtained directly from the construction site. Example 1

[0021] A shield tunnel wall backfill grout, by weight, is composed of the following raw materials: 15 parts of curing binder, 80 parts of slag, and 78 parts of water; the curing binder is composed of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silica powder in a mass ratio of 30:2:35:20:5; the inorganic acid is sulfuric acid with a mass concentration of 30%. Example 2

[0022] A shield tunnel wall backfill grout, by weight, is composed of the following raw materials: 20 parts of curing binder, 90 parts of slag, and 107 parts of water; the curing binder is composed of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silica powder in a mass ratio of 35:3:40:30:10; the inorganic acid is 40% sulfuric acid by mass. Example 3

[0023] A shield tunnel wall backfill grout, by weight, is composed of the following raw materials: 16 parts of curing binder, 82 parts of slag, and 80 parts of water; the curing binder is composed of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silica powder in a mass ratio of 31:2.2:36:21:5.5; the inorganic acid is 35% hydrochloric acid by mass concentration. Example 4

[0024] A shield tunnel wall backfill grout, by weight, is composed of the following raw materials: 18 parts of curing binder, 88 parts of slag, and 105 parts of water; the curing binder is composed of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silica powder in a mass ratio of 32:2.6:38:28:9; the inorganic acid is sulfuric acid with a mass concentration of 34%. Example 5

[0025] A shield tunnel wall backfill grout, by weight, is composed of the following raw materials: 17 parts of curing binder, 85 parts of slag, and 90 parts of water; the curing binder is composed of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silica powder in a mass ratio of 33:2.5:37:25:6; the inorganic acid is hydrochloric acid with a mass concentration of 32%. Example 6

[0026] A shield tunnel wall backfill grout, by weight, is composed of the following raw materials: 16 parts of curing binder, 85 parts of slag, and 96 parts of water; the curing binder is composed of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silica powder in a mass ratio of 32:2.5:36:24:8; the inorganic acid is hydrochloric acid with a mass concentration of 37%. Example 7

[0027] The preparation method of the grouting fluid behind the shield tunnel wall described in Example 1 includes the following steps: Sebacic acid dihydrazide, inorganic acid, xanthan gum, and dicyandiamide were placed in a mixing device and stirred for 10 minutes. After mixing evenly, the mixture was allowed to stand for 7 minutes. Then, silicon phosphate powder was added and stirred for 10 minutes. After mixing evenly, the mixture was allowed to stand for 7 minutes to obtain the curing adhesive additive. The mass ratio of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silicon phosphate powder is 30:2:35:20:5; the inorganic acid is sulfuric acid with a mass concentration of 30%. Mix 15 parts of curing binder, 80 parts of slag and 78 parts of water, start stirring, stir at 900 r / min for 10 minutes, and mix evenly to obtain the grouting slurry for the shield wall. Example 8

[0028] The preparation method of the shield wall backfill grout described in Example 2 includes the following steps: Sebacic acid dihydrazide, inorganic acid, xanthan gum, and dicyandiamide were placed in a mixing device and stirred for 15 minutes. After mixing evenly, the mixture was allowed to stand for 10 minutes. Then, silicon phosphate powder was added and stirred for 15 minutes. After mixing evenly, the mixture was allowed to stand for 10 minutes to obtain the curing adhesive additive. The mass ratio of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silicon phosphate powder is 35:3:40:30:10; the inorganic acid is sulfuric acid with a mass concentration of 40%. Mix 20 parts of curing binder, 90 parts of slag and 107 parts of water, start stirring at a speed of 950 r / min for 12 minutes, and mix evenly to obtain the grouting slurry for the shield wall. Example 9

[0029] The preparation method of the grouting fluid behind the shield wall described in Example 3 includes the following steps: Sebacic acid dihydrazide, inorganic acid, xanthan gum, and dicyandiamide were placed in a mixing device and stirred for 11 minutes. After mixing evenly, the mixture was allowed to stand for 9 minutes. Then, silicon phosphate powder was added and stirred for 14 minutes. After mixing evenly, the mixture was allowed to stand for 8 minutes to obtain the curing adhesive additive. The mass ratio of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silicon phosphate powder is 31:2.2:36:21:5.5; the inorganic acid is hydrochloric acid with a mass concentration of 35%. Mix 16 parts of curing binder, 82 parts of slag and 80 parts of water, start stirring at a speed of 910 r / min for 10 minutes, and mix evenly to obtain the grouting slurry for the shield wall. Example 10

[0030] The preparation method of the grout behind the shield wall described in Example 4 includes the following steps: Sebacic acid dihydrazide, inorganic acid, xanthan gum, and dicyandiamide were placed in a mixing device and stirred for 14 minutes. After mixing evenly, the mixture was allowed to stand for 8 minutes. Then, silicon phosphate powder was added and stirred for 12 minutes. After mixing evenly, the mixture was allowed to stand for 8 minutes to obtain the curing adhesive additive. The mass ratio of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silicon phosphate powder is 32:2.6:38:28:9; the inorganic acid is sulfuric acid with a mass concentration of 34%. Mix 18 parts of curing binder, 88 parts of slag and 105 parts of water, start stirring, stir at 940 r / min for 12 minutes, mix evenly to obtain the grouting slurry behind the shield wall. Example 11

[0031] The preparation method of the grout behind the shield wall described in Example 5 includes the following steps: Sebacic acid dihydrazide, inorganic acid, xanthan gum, and dicyandiamide were placed in a mixing device and stirred for 13 minutes. After mixing evenly, the mixture was allowed to stand for 9 minutes. Then, silicon phosphate powder was added and stirred for 12 minutes. After mixing evenly, the mixture was allowed to stand for 8 minutes to obtain the curing adhesive additive. The mass ratio of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silicon phosphate powder is 33:2.5:37:25:6; the inorganic acid is hydrochloric acid with a mass concentration of 32%. Mix 17 parts of curing binder, 85 parts of slag and 90 parts of water, start stirring, stir at 920 r / min for 11 minutes, and mix evenly to obtain the grouting slurry behind the shield wall. Example 12

[0032] The preparation method of the shield wall backfill grout described in Example 6 includes the following steps: Sebacic acid dihydrazide, inorganic acid, xanthan gum, and dicyandiamide were placed in a mixing device and stirred for 12 minutes. After mixing evenly, the mixture was allowed to stand for 8 minutes. Then, silicon phosphate powder was added and stirred for 12 minutes. After mixing evenly, the mixture was allowed to stand for 8 minutes to obtain the curing adhesive additive. The mass ratio of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide, and silicon phosphate powder is 32:2.5:36:24:8; the inorganic acid is hydrochloric acid with a mass concentration of 37%. Mix 16 parts of curing binder, 85 parts of slag and 96 parts of water, start stirring, stir at 940 r / min for 12 minutes, and mix evenly to obtain the grouting slurry for the shield wall.

[0033] Test on the performance of grout behind the shield wall To verify the performance of the shield wall backfill grout of the present invention, the fluidity, consistency, strength, viscosity and compaction rate of the shield wall backfill grout were tested, and the results are shown in Table 1.

[0034] Among them, (1) mixing method: refer to JGJ / T 70-2009 "Standard for Test Method of Basic Performance of Building Mortar"; (2) bleeding rate: according to GB / T 25182-2010 "Prestressed Duct Grouting Agent" standard, the bleeding rate of the grout is determined by weighing method. The container is tilted at intervals, and the water precipitated in the grout is sucked out with a pipette. The bleeding rate at each time is calculated by calculating the ratio of the bleeding volume to the initial volume of the grout; (3) consistency: refer to JGJ / T 70-2009 "Standard for Test Method of Basic Performance of Building Mortar" to conduct the wall grouting consistency test. The consistency of the mortar is judged by the cone penetration of the mortar consistency meter falling freely; (4) fluidity: the mortar fluidity test refers to the current national standard GB / T The application of cement-based grouting materials is carried out in accordance with 50448-2015. The size of the truncated cone mold is 70cm×60cm×100cm. The grout in the mold should be flush with the top of the mold. The mortar fluidity is the average of the maximum and minimum diameters after the grout spreads. (5) Setting time: The setting time test of the grouting behind the wall is determined by the penetration resistance. The actual penetration resistance value is measured 2 hours after the mortar is formed. The initial measurement interval is 0.5h. After the measured penetration resistance reaches 0.3MPa, the measurement interval is changed to 15min. The measurement is stopped when the penetration resistance reaches 0.7MPa. After the penetration resistance changes with time, the setting time of the mortar is the time when the penetration resistance is 0.5MPa. The test block is subjected to uniaxial compression test, and the compressive strength at 1d, 7d and 28d is measured respectively. The compressive strength of the cube is the ratio of the cube's failure pressure to the specimen's bearing area; (6) Stone rate test: refer to T / CECS563-2018 "Technical Specification for Application of Synchronous Grouting Materials in Shield Tunnel".

[0035] Table 1 Performance test data of the grouting fluid obtained from Examples 1-6 of the shield tunnel wall

[0036] As can be seen from the results in Table 1, under standard curing conditions, the initial setting time, compressive strength, funnel viscosity, and solidification rate of the grout behind the shield wall of the present invention all meet the specifications. The indoor compressive strength of the grout after 1 day (24 hours) is greater than 2.5 MPa, the indoor compressive strength after 28 days is greater than 5.5 MPa, the funnel viscosity is less than 25 s, and the solidification rate is as high as 99% or more, which meets the specifications.

[0037] The grouting fluid for shield tunneling can be obtained from soil samples taken at the construction site. The curing binder can be used in combination with various soil types to obtain a fluid and high-strength grout that meets the requirements of construction.

Claims

1. A grouting fluid for backfilling tunnel walls, characterized in that: The grouting fluid behind the shield wall is composed of the following raw materials by weight: 15-20 parts of curing binder, 80-90 parts of slag and soil and 78-107 parts of water; the curing binder is composed of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide and silica powder. The inorganic acid is sulfuric acid or hydrochloric acid with a mass concentration of 30-40%; The mass ratio of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide and silicon phosphate powder is 30~35:2~3:35~40:20~30:5~10; The molar ratio of SiO2 / P2O5 in the silicon phosphate powder is 1.2~2.

5.

2. The grouting fluid for backfilling a tunnel boring machine according to claim 1, characterized in that: The grouting fluid behind the shield wall is composed of the following raw materials by weight: 16 parts of curing binder, 85 parts of slag and soil and 96 parts of water.

3. The grouting fluid for backfilling a tunnel boring machine according to claim 1, characterized in that: The waste soil refers to the construction waste soil from the construction site.

4. The grouting fluid for backfilling a tunnel boring machine according to claim 1, characterized in that: The mass ratio of sebacic acid dihydrazide, inorganic acid, xanthan gum, dicyandiamide and silicon phosphate powder is 32:2.5:36:24:

8.

5. The grouting fluid for backfilling a tunnel boring machine according to claim 1, characterized in that: The water content is 92-97% of the total mass of the solidifying binder and the slag.

6. The method for preparing the grouting fluid behind the shield tunnel wall as described in claim 1, characterized in that: By weight, 15-20 parts of curing binder, 80-90 parts of slag and 78-107 parts of water are mixed evenly to obtain the grouting slurry behind the shield wall.

7. The method for preparing the grouting fluid behind the shield tunnel wall according to claim 6, characterized in that: The preparation process of the curing binder includes the following steps: Sebacic acid dihydrazide, inorganic acid, xanthan gum, and dicyandiamide are placed in a mixing device and stirred for 10-15 minutes. After mixing evenly, the mixture is allowed to stand for 7-10 minutes. Then, silicon phosphate powder is added and stirred for 10-15 minutes. After mixing evenly, the mixture is allowed to stand for 7-10 minutes to obtain the curing adhesive additive.

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