A method for determining the slurry proportioning of large-diameter shield tunnel synchronous grouting double-liquid slurry

Abstract

The technical problem to be solved by the present application is to provide a large-diameter shield tunnel synchronous grouting double-liquid slurry slurry proportioning determination method. The reference proportioning is determined through preliminary investigation, different water-cement ratio and A liquid and B liquid volume ratio tests are designed to determine the influence law of slurry performance, and the final slurry proportioning is determined through field construction test, feedback of segment floating and segment ring joint misalignment. The method can not only meet the requirements of the construction site, but also scientifically adjust the slurry proportioning, and can be popularized and used in shield tunnel construction.

Description

Technical Field

[0001] This invention belongs to the field of shield tunnel construction in civil engineering, and specifically relates to a method for determining the slurry mix ratio of a dual-liquid grout for synchronous grouting in large-diameter shield tunnels. Background Technology

[0002] Shield tunneling is widely used in subway tunnels, highway tunnels, and water conveyance tunnels. The main processes of shield tunneling include shield advancement, synchronous grouting, segment assembly, and secondary grouting. Because the cutterhead radius of the shield machine is larger than the outer diameter of the segments, a gap exists between the segments and the ground after segment formation. Without synchronous grouting to fill this gap, excessive surface settlement will occur. In addition, synchronous grouting also helps to ensure uniform stress on the segments and forms a waterproof seal. Synchronous grout can be categorized by its activity into single-component inert grout, single-component active grout, and two-component grout. Due to the different components, the grout properties vary significantly. Two-component grout, in particular, has a wide adjustable setting time range and high early strength, making it suitable for construction in soft soil and water-rich strata.

[0003] The main components of a two-component grout are water, cement, bentonite, stabilizer, and water glass, with water glass also known as the B-component grout. In grout preparation, water, cement, bentonite, and stabilizer are first mixed according to a specific ratio to form the A-component grout. Then, the A-component and B-component grouts are mixed in a specific volume ratio to form the construction two-component grout. Because the two-component grout has many components, and different components have different effects on the gelation time and strength, different mix proportions often result in different properties. Since the forming quality problems of segment floating and misalignment in shield tunnel construction are closely related to these properties, a suitable grout mix proportion will significantly solve these segment forming quality problems. Therefore, finding a suitable grout mix proportion has become an urgent technical problem to be solved. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method for determining the slurry mix ratio of a dual-component grout for synchronous grouting in large-diameter shield tunnels. A baseline mix ratio is determined through preliminary research, and experiments are designed with different water-cement ratios and volume ratios of liquid A and liquid B to clarify their influence on slurry performance. Through on-site construction tests, feedback on segment floating and segment circumferential joint misalignment is obtained to determine the final slurry mix ratio. This method is based on the needs of the construction site and allows for scientific adjustment of the slurry mix ratio, and can be widely used in shield tunnel construction.

[0005] This invention is achieved through the following technical solution: A method for determining the mix proportion of a dual-component grout for synchronous grouting in large-diameter shield tunnels includes the following steps: S01. Determine the grout performance indicators based on engineering geological conditions and requirements; S02. Determine the baseline mix ratio of water-cement ratio for liquid A based on research or construction experience, and determine the baseline mix ratio of volume ratio of liquid A and liquid B. S03. Based on the baseline mix ratio in step S02, design slurry performance tests with different water-cement ratios and volume ratios of liquid A and liquid B. S04. Test the specific gravity of liquid A, the gelation time of the two-liquid slurry, and the compressive strength. S05. Fitting analysis of the specific gravity of liquid A slurry, gelation time of double liquid slurry, and compressive strength; S06. Based on the slurry performance law fitted in step S05 and the slurry performance index in step S01, determine the water-cement ratio of liquid A and the volume ratio of liquid A to liquid B, and then determine the slurry mix ratio. S07. Prepare dual grout and conduct on-site construction tests, and simultaneously measure the misalignment of the floating circumferential joints of the segments. S08. Determine whether the amount of segment floating and the amount of circumferential joint misalignment meet the construction requirements. If not, adjust the water-cement ratio of liquid A and the volume ratio of liquid A to liquid B according to the fitting law, and repeat step S07. S09. When the amount of segment floating and the amount of circumferential joint misalignment meet the construction requirements, the grout mix ratio is determined and used for construction.

[0006] Furthermore, in step S02, the components of liquid A are cement, bentonite, stabilizer, and water, with a standard mix ratio of cement:bentonite:stabilizer:water = 350kg:30kg:3.5kg:813kg. The standard mix ratio of water-cement ratio of liquid A is 2.3:1. Liquid B is water glass, and the standard mix ratio of volume ratio of liquid A to liquid B is 15.7:1.

[0007] Furthermore, in step S03, Specific gravity of liquid A: ; In the formula: denoted as slurry specific gravity; a represents the water-cement ratio of slurry A.

[0008] Furthermore, in step S03, gelation time: In the formula: , where is the slurry setting time in seconds; a is the water-cement ratio of slurry A; b is the volume ratio of slurry A to slurry B.

[0009] Furthermore, in step S03, 1-day strength of slurry: In the formula: The strength of the slurry in 1 day is expressed in MPa; a is the water-cement ratio of slurry A; b is the volume ratio of slurry A to slurry B.

[0010] Furthermore, in step S01, the preliminary performance indicators of the slurry are determined as follows: gel time 5~20s; 1d strength greater than or equal to 0.5Mpa.

[0011] The beneficial effects achieved by this invention compared with the prior art are as follows: 1. After preliminary research, the baseline mix ratio was determined, and tests were designed with different water-cement ratios and volume ratios of liquid A and liquid B to clarify their influence on grout performance. Through on-site construction tests, feedback on segment floating and segment circumferential misalignment was obtained to determine the final grout mix ratio. This method starts from engineering requirements, uses indoor grout test results as the basis for adjusting the grout mix ratio, and determines whether the grout mix ratio meets the construction requirements by measuring the misalignment and uplift of the tunnel segments during on-site construction, thereby determining the final grout mix ratio. This method for determining the grout mix ratio of the simultaneous grouting dual-component grout is closely linked to engineering projects and allows for scientific adjustment of the grout mix ratio based on engineering needs and feedback, achieving the goal of ensuring tunnel quality during formation. 2. Based on engineering geological conditions, this invention can employ various methods such as engineering surveys, indoor slurry tests, and on-site segment tests to scientifically confirm the slurry ratio, ensuring the quality of segment formation. It can be widely used in similar projects. Attached Figure Description

[0012] Figure 1 Method for determining the ratio of two-component slurry Figure 2 Fitting the specific gravity of solution A under different water-cement ratios Figure 3 Fitting of setting time for different water-cement ratios Figure 4 Fitting of gelation time for different slurry volume ratios Figure 5 Fitting initial setting time for different water-cement ratios Figure 6 Fitting the final setting time for different water-cement ratios Figure 7 Fitting initial setting time for different slurry volume ratios Figure 8 Fitting final setting time for different slurry volume ratios Figure 9 1d strength fitting for different water-cement ratios Figure 10 1-day strength fitting for different slurry volume ratios Detailed Implementation The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0013] In the description of the invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.

[0014] S01, such as Figure 1 As shown, taking a certain construction project as an example, the shield tunnel of this project mainly passes through silty sand layer and silty clay layer. The main performance indicators of the grout are initially determined to be: gel time 5~20s; 1d strength greater than or equal to 0.5Mpa, etc.

[0015] Based on similar engineering surveys, S02 determined that the main components of liquid A are cement, bentonite, stabilizer, and water, with a mixing ratio of cement:bentonite:stabilizer:water = 350kg:30kg:3.5kg:813kg. The baseline water-cement ratio of liquid A is 2.3:1. Liquid B is water glass, and the baseline volume ratio of liquid A to liquid B is 15.7:1.

[0016] S03. Based on the baseline mix ratio in step S02, design slurry performance tests with different water-cement ratios and volume ratios of liquid A and liquid B. Based on the reference ratio, the water-cement ratio of liquid A is designed to be 1.9:1, 2.1:1, 2.3:1 (reference ratio), 2.5:1, and 2.7:1, and the slurry ratio of liquid A to liquid B is 5.7:1, 10.7:1, 15.7:1 (reference ratio), 20.7:1, and 25.7:1. S04. Measure the specific gravity of liquid A slurry, the gelation time of the two-liquid slurry, and the compressive strength under the above-mentioned different proportions of the slurry.

[0017] S05, such as Figure 2-10 As shown, the fitting analysis reveals the following patterns in the specific gravity of liquid A slurry, gelation time of the two-liquid slurry, initial setting time, final setting time, and compressive strength: Specific gravity of liquid slurry: gelation time: Initial setting time: Final setting time: 1-day strength of slurry: In the formula This refers to the specific gravity of the slurry, expressed in g / cm³. 3 , This refers to the gelation time of the slurry, measured in seconds. This refers to the initial setting time of the slurry, in minutes. This is the final setting time of the slurry, in minutes. The strength of the slurry is expressed in MPa over 1 day; a is the water-cement ratio of slurry A; b is the volume ratio of slurry A to slurry B.

[0018] S06. According to the engineering specifications, the grout setting time is 5~20s, and the 1d strength is greater than or equal to 0.5MPa. Substituting the above indicators into the fitting formula for setting time and grout 1d strength, it can be seen that the water-cement ratio of 2.3:1 and the volume ratio of liquid A to liquid B of 15.7:1 determined by the survey meet the grout performance requirements. The grout setting time is 8.53s, and the 1d strength is 1.12MPa.

[0019] S07. According to the grout mix ratio of cement: bentonite: stabilizer: water = 350kg: 30kg: 3.5kg: 813kg, and the volume ratio of liquid A to liquid B is 15.7:1, prepare the grout for construction, and simultaneously monitor the data of segment floating and circumferential joint misalignment.

[0020] S08. Determine whether the amount of segment floating and the amount of circumferential joint misalignment meet the construction requirements. If not, adjust the water-cement ratio of liquid A and the volume ratio of liquid A to liquid B according to the fitting law, and repeat step S07. S09. When the amount of segment floating and the amount of circumferential joint misalignment meet the construction requirements, the grout mix ratio is determined and used for construction.

[0021] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort.

Claims

1. A method for determining the slurry mix ratio of a dual-component grout for synchronous grouting in a large-diameter shield tunnel, characterized in that, Includes the following steps: S01. Based on the engineering geological conditions and requirements, determine the performance indicators of the grout; the preliminary performance indicators of the grout are: gel time 5~20s; 1d strength greater than or equal to 0.5Mpa; S02. Determine the baseline mix ratio of water-cement ratio for liquid A based on research or construction experience, and determine the baseline mix ratio of volume ratio of liquid A and liquid B. The components of liquid A are cement, bentonite, stabilizer, and water, and the baseline mix ratio is cement:bentonite:stabilizer:water = 350kg:30kg:3.5kg:813kg. The baseline mix ratio of water-cement ratio for liquid A is 2.3:

1. Liquid B is water glass, and the baseline mix ratio of volume ratio of liquid A to liquid B is 15.7:

1. S03. Based on the baseline mix ratio in step S02, design slurry performance tests with different water-cement ratios and volume ratios of liquid A and liquid B. Specific gravity of liquid A: ; In the formula: ρ is the specific gravity of the slurry; a is the water-cement ratio of slurry A. gelation time: ; In the formula: This refers to the gelation time of the slurry, measured in seconds. a is the water-cement ratio of slurry A; b is the volume ratio of slurry A to slurry B. 1-day strength of slurry: ; In the formula: The strength of the slurry in 1 day is expressed in MPa; a is the water-cement ratio of slurry A; b is the volume ratio of slurry A to slurry B. S04. Test the specific gravity of liquid A, the gelation time of the two-liquid slurry, and the compressive strength. S05. Fitting analysis of the specific gravity of liquid A slurry, gelation time of double liquid slurry, and compressive strength; S06. Based on the slurry performance law fitted in step S05 and the slurry performance index in step S01, determine the water-cement ratio of liquid A and the volume ratio of liquid A to liquid B, and then determine the slurry mix ratio. S07. Prepare dual grout and conduct on-site construction tests, and simultaneously measure the misalignment of the floating circumferential joints of the segments. S08. Determine whether the amount of segment floating and the amount of circumferential joint misalignment meet the construction requirements. If not, adjust the water-cement ratio of liquid A and the volume ratio of liquid A to liquid B according to the fitting law, and repeat step S07. S09. When the amount of segment floating and the amount of circumferential joint misalignment meet the construction requirements, the water-cement ratio of liquid A and the volume ratio of liquid A to liquid B are determined, and the mixing ratio is used for construction.

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