A method for reinforcing shield tunnel wall post grouting control by compartment grouting

Abstract

The application relates to a kind of reinforced shield tunnel wall post-grouting control compartment grouting method, which comprises the following steps: S1 using sulphate paper pulp to make kraft paper air bag, and sticking the kraft paper air bag behind No.1 pipe piece, No.4 pipe piece and No.5 pipe piece; S2 immediately grouting No.1 compartment through grouting hole after pipe piece assembly with shield advancing; S3 grouting No.4 compartment and No.5 compartment through grouting hole; S4 pressure grouting No.2 compartment and No.3 compartment through grouting hole to fill the gap; S5 secondary grouting to supplement slurry through grouting hole according to the volume shrinkage after slurry solidification. The method divides the shield tail gap into multiple compartments for pipe piece wall post-grouting construction by the internal space of kraft paper air bag and the air bag interval space, and can effectively strengthen the control of shield tunnel wall post-grouting process, slurry solidification and diffusion by the retention of kraft paper air bag to slurry. The shield posture and pipe piece position are regulated by adjusting the grouting pressure of each compartment, and the grouting of pipe piece top closed compartment effectively prevents slurry loss and pipe piece floating, ensures the compactness and enhances the guarantee degree of grouting construction quality.

Description

Technical Field

[0001] This invention relates to the field of grouting behind shield tunnel walls, and specifically to a compartmentalized grouting method for enhancing the control of grouting behind shield tunnel walls. Background Technology

[0002] With the rapid development of urban infrastructure construction, the construction of underground tunnels such as subways is in large quantities. Since blasting is largely prohibited in urban areas, shield tunnels, due to their advantages such as minimal environmental impact, good adaptability to geological formations, high degree of mechanization, and fast construction speed, are widely used in urban underground tunnel construction, including both soil-based and rock-based TBMs. For the smooth advancement of the shield machine, the inner diameter of the shield shell needs to be larger than the outer diameter of the tunnel segments. Combined with the shield shell thickness and over-excavation, this means that the cutterhead excavation diameter during shield tunneling must be larger than the outer diameter of the tunnel segments, leading to the formation of a tail gap. Currently, backfill grouting is often used in shield construction to fill this tail gap. Backfill grouting plays a crucial role in fixing the position of the tunnel segments, providing stress conditions for the segments, and controlling ground deformation during shield construction. These critical roles often determine whether the shield can advance smoothly. Therefore, in the shield construction process, segment lining and backfill grouting, as one of the three major elements of shield construction, play a decisive role in the quality of shield construction.

[0003] Currently, backfill grouting is mainly divided into shield tail grouting and segment grouting according to the grouting location, and into synchronous grouting and secondary grouting according to the injection time. The injected grout is mainly divided into single-component grout and double-component grout. However, during backfill grouting construction, improper construction often leads to problems such as segment floating, surface collapse or heave, and damage to segments and bolts. To improve the quality of backfill grouting, the current consensus is to strengthen the control of grouting construction by enhancing the control of both grout material configuration and the grouting process, thereby achieving controllable and improved backfill grouting quality. However, there are currently no clear specifications for grouting procedures, grouting pressure, and grout formulation. Simulation studies of grout injection and diffusion processes and control methods for backfill grouting are still in the exploratory stage. Therefore, it is necessary to design a grouting method that can strengthen the control and management of both the configuration of grouting materials and the grouting process in shield tunnels, improve the grout density of backfill grouting, and prevent problems such as segment floating. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this invention is to provide a compartmentalized grouting method that enhances the control of both the preparation of the grout material and the grouting process behind the shield tunnel wall.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a compartmentalized grouting method for enhancing the control of grouting behind the shield tunnel wall, as shown in the attached figure. Figure 1 ~Attached Figure 8 As shown, it includes the following steps:

[0006] S1: Use sulfate pulp to make kraft paper airbags, and attach the kraft paper airbags to the back of tube segments 1, 4, and 5.

[0007] Each ring of tunnel segments in the shield tunnel design is composed of 5 segments. The top segment is segment 1, the left and right sides are segments 2 and 3 respectively, and the bottom two segments are segments 4 and 5 respectively.

[0008] S101: Making Kraft Paper Airbags:

[0009] Obtain the tube segment design parameters and production speed to determine the required speed for kraft paper airbags, and determine the required amount of sulfate pulp. Produce sulfate pulp, inject the sulfate pulp into a mold, and form it into kraft paper airbags:

[0010] S102: Attach the kraft paper airbag to the outer side of the tube segment:

[0011] Remove the finished kraft paper airbag in its original state, apply glue to the outside of the tube segment, and attach the kraft paper airbag to the outside of the tube segment, ensuring that the grouting hole on the tube segment coincides with the opening of the kraft paper airbag.

[0012] After the glue dries, spray water vapor onto the kraft paper airbag to soften it, fold the kraft paper airbag and store it, and then store the tube in a rainproof place for later use.

[0013] The tubes for attaching the kraft paper airbag should be tubes No. 1, No. 4, and No. 5.

[0014] S2: As the tunnel boring machine advances, grouting is immediately injected into compartment 1 through the grouting holes after the segments are assembled.

[0015] The tunnel boring machine was advanced normally, and the segment assembly and bolt installation were completed. Immediately after the segment assembly, grout was injected into the No. 1 compartment in the kraft paper airbag behind the No. 1 segment through the grouting hole on the No. 1 segment. Grouting was stopped immediately after the grout pressure reached 0.2MPa.

[0016] The grouting operation time for compartment 1 shall not exceed 5 minutes;

[0017] S3: Grouting is performed on compartments 4 and 5 through the grouting holes;

[0018] After the grouting of compartment 1 is completed, grouting is immediately injected into compartments 4 and 5 inside the kraft paper air bladders behind the No. 4 and No. 5 tube segments through the grouting holes on the No. 4 and No. 5 tube segments. Grouting is stopped immediately after the grout pressure in the compartment reaches 0.2MPa.

[0019] The grouting operation time for compartments 4 and 5 shall not exceed 5 minutes;

[0020] S4: Pressure grouting is performed on compartments 2 and 3 through the grouting holes to fill the voids.

[0021] After the grouting of compartments 4 and 5 is completed, grouting is immediately injected into compartments 2 and 3 behind the segments through the grouting holes on segments 2 and 3. Grouting is stopped when the grout pressure in the compartments reaches and stabilizes at 0.2 MPa. The grout pressure in compartments 2 and 3 needs to be continuously monitored to ensure that it is not lower than 5 minutes. If the grout pressure drops during this period, grout needs to be added immediately until the grout pressure is maintained at 0.2 MPa.

[0022] If the grout pressure cannot reach or be maintained at 0.2 MPa, grouting should be stopped. After the aforementioned single-component grout has set, cement grout and water glass should be mixed at a volume ratio of 1:1 and injected through the grouting hole.

[0023] S5: To address the volume shrinkage issue after grout solidification, secondary grouting is performed through the grouting holes to replenish the grout.

[0024] After the grout solidifies, if cavities are found due to grout loss, the cement grout and water glass are mixed at a volume ratio of 1:1 and injected through the grouting holes of pipe segments No. 2 and No. 3 at a pressure of 0.4 MPa to fill the cavities caused by grout loss and to fill the gaps caused by the solidification and shrinkage of the grout in the kraft paper airbag.

[0025] As an optimization, the specific manufacturing method of the kraft paper airbag in S101 is as follows:

[0026] S101-1: Production of sulfate pulp, a raw material for kraft paper:

[0027] A chemical agent is pre-prepared, consisting of 1.0–1.1 mol / L sodium hydroxide and 0.2 mol / L sodium sulfide. The pH value of the resulting chemical agent is between 13.6 and 14.0 to meet the requirements. The papermaking raw materials and the chemical agent are placed together in a digester and kept at 170°C–175°C for 90 minutes to decompose the lignin. After spraying, steam recovery, washing, and filtration, the resulting pulp is the desired sulfate pulp.

[0028] The papermaking raw material is waste paper pulp or a variety of fiber raw materials, including wood, bamboo, rice straw, stalks, wheat straw, cotton and hemp, and one or more of these are used in combination.

[0029] S101-2: Assemble and adjust the kraft paper airbag forming mold according to the following steps:

[0030] According to the size of the pipe segment, a pipe segment-shaped double-layer clamp mold is made. The inside of the mold is a high-temperature resistant inflatable airbag mold made of rubber, and the outside is an iron mold. It is ensured that the distance between the inner airbag mold and the outer iron mold is equal and 1.0mm to 1.2mm after inflation, so as to ensure that the thickness of the formed kraft paper airbag is between 1.0mm and 1.2mm. A large hole is made on the iron mold on the side to be attached to the pipe segment. The position of the hole corresponds to the grouting hole on the pipe segment, which serves as a channel for water vapor to be discharged and pulp to be injected.

[0031] The outer iron mold should consist of two symmetrical parts, which are assembled by locking buckles when forming the kraft paper airbag.

[0032] S101-3: Molded Kraft Paper Airbag

[0033] The prepared sulfate pulp is injected into the cavity between the inner and outer molds. The inner rubber air bladder mold is inflated to form the pulp and pressurize it to expel moisture. The mold is then heated to 70℃~80℃ to dry and shape the kraft paper air bladder. No pulp should remain at the opening of the outer iron mold during the injection of sulfate pulp and drying process.

[0034] S101-4: Remove the kraft paper airbag:

[0035] Empty the gas from the internal airbag mold and open the external iron mold. Remove the finished kraft paper airbag in its original shape. The environment in which the kraft paper airbag is removed should be kept at a temperature of no less than 40°C and a relative humidity of no more than 15% to maintain the shape of the kraft paper airbag.

[0036] As an optimization, the formed kraft paper airbag should also meet the following performance requirements:

[0037] 1) The inflation pressure resistance of the kraft paper airbag shall not be less than 0.35MPa: Use an air compressor to pump air into the kraft paper airbag through the injection hole on the tube segment, monitor the air pressure inside the kraft paper airbag, and continue to pump air into the kraft paper airbag until the kraft paper airbag is destroyed. It is required that no air leakage occurs on the surface and at the bonding point of the kraft paper airbag before the air pressure reaches 0.3MPa. When the kraft paper airbag completely loses its airtightness and is destroyed, the peak air pressure inside the kraft paper airbag shall not be less than 0.35MPa.

[0038] 2) Water resistance: Water is injected into the kraft paper air bladder through the grouting holes on the pipe segment until the water pressure reaches 0.25MPa, and the timing begins. The time when obvious leakage occurs shall not be earlier than 15 minutes.

[0039] 3) To maintain the slurry capacity, pressure slurry is injected into the kraft paper air bladder through the slurry injection hole on the tube. Timing starts after the slurry pressure reaches 0.25MPa. The kraft paper air bladder will not be destroyed within 15 minutes.

[0040] As an optimization, the grout injected into compartment 1 in step S2 is a single-liquid grout with added accelerator. The specific mass ratio of the components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29. At the same time, 3% of the cement mass of accelerator needs to be added. The performance requirements of the grout are: consolidation shrinkage rate not exceeding 5%, initial setting time 1-5 minutes, final setting time 5-12 minutes, 24-hour consolidation strength not less than 0.6 MPa, and 28-day consolidation strength not less than 2.1 MPa.

[0041] The quick-setting agent is a powder prepared by mixing alumina clinker, sodium carbonate, and quicklime in a mass ratio of 1:0.8:0.3-0.5.

[0042] The slurry can be treated with 2 kg of calcium chloride per 1000 kg of slurry as an early strength agent.

[0043] As an optimization, the grout injected into compartments 4 and 5 in step S3 is a single-liquid grout with added accelerator. The specific mass ratio of the components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29. At the same time, 3% of the cement mass of accelerator needs to be added. The performance requirements of the grout are: consolidation shrinkage rate not exceeding 5%, initial setting time 1-5 minutes, final setting time 5-12 minutes, 24-hour consolidation strength not less than 0.6 MPa, and 28-day consolidation strength not less than 2.1 MPa.

[0044] The quick-setting agent is a powder made of alumina clinker, sodium carbonate, and quicklime in a mass ratio of 1:0.8:0.3 to 0.5.

[0045] As an optimization, the grout injected into compartments 2 and 3 in step S4 is a single-liquid grout with added accelerator. The specific mass ratio of the components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29. At the same time, 3% of the cement mass of accelerator needs to be added. The performance requirements of the grout are: consolidation shrinkage rate not exceeding 5%, initial setting time 1-5 minutes, final setting time 5-12 minutes, 24-hour consolidation strength not less than 0.6 MPa, and 28-day consolidation strength not less than 2.1 MPa.

[0046] The quick-setting agent is a powder made of alumina clinker, sodium carbonate, and quicklime in a mass ratio of 1:0.8:0.3 to 0.5.

[0047] As an optimization, if the number of segments per ring is not 5:

[0048] The method for selecting the tunnel segments for attaching kraft paper airbags to the back is as follows: first select one segment at the top of the tunnel to attach the kraft paper airbag, and then select one segment every other segment for attaching the kraft paper airbag.

[0049] The grouting construction sequence for each compartment is as follows: first construct the top compartment of the tunnel, then construct the bottom compartment, first construct the compartment inside the kraft paper airbag, and then construct the other compartments.

[0050] The method for selecting the type of grout injected into each compartment is as follows: the compartment at the top of the tunnel uses the grout injected into compartment 1 in step S2; the compartment at the bottom of the tunnel uses the grout injected into compartments 4 and 5 in step S3; and the compartments behind the tunnel lining walls on both sides use the grout injected into compartments 2 and 3 in step S4.

[0051] It should be noted that in this method, descriptions of orientation such as "inner side of the tunnel segment" and "outer side of the tunnel segment" all refer to the center of the tunnel cross-section as the inside.

[0052] Compared with the prior art, the present invention has the following advantages:

[0053] The present invention provides a compartmentalized grouting method for enhancing the control of grouting behind the shield tunnel wall. This method involves attaching prefabricated kraft paper airbags to the outside of the tunnel lining segments. The internal space of the kraft paper airbags and the space between the airbags divide the shield tail gap into multiple compartments. A sequence of grouting operations and key time points are arranged for each compartment. The grout material preparation method and grouting process within each compartment are individually controlled. Relying on the grout retention properties of the kraft paper airbags, the method effectively enhances the control of the grouting process behind the shield tunnel wall and the solidification and diffusion of the grout. By adjusting the grouting pressure of each compartment, the shield attitude and segment position can be controlled. Grouting in the closed compartments at the top of the segments allows for initial control of the segment position and ensures that the top grout is filled, effectively preventing grout loss and segment floating, ensuring density, and enhancing the quality assurance of the grouting construction. This method enhances the controllability of grouting behind the shield tunnel wall. As a grouting method that can strengthen the control and management of both the grouting material configuration and the grouting process behind the shield tunnel wall, it realizes the refinement, controllability and scientification of grouting behind the shield tunnel wall, improves the density of the grout behind the wall, and prevents problems such as segment floating. Attached Figure Description

[0054] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same parts use the same names throughout the drawings. In the drawings:

[0055] Figure 1 —This is a simplified flowchart of the method of the present invention.

[0056] Figure 2 —A schematic diagram for making a kraft paper airbag.

[0057] Figure 3 —A schematic diagram for demolding and removing the kraft paper airbag.

[0058] Figure 4—A diagram illustrating the pasting of the kraft paper airbag.

[0059] Figure 5 —A tunnel cross-section diagram for completing the segment assembly.

[0060] Figure 6 —A tunnel cross-section diagram for completing the grouting of compartment 1.

[0061] Figure 7 —To complete the tunnel cross-section diagram during the grouting of chambers 4 and 5.

[0062] Figure 8 —This is a cross-sectional view of the tunnel when grouting is fully completed. Detailed Implementation

[0063] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0064] A compartmentalized grouting method for enhancing grouting control behind shield tunnel walls, as shown in the attached figure. Figure 1 ~Attached Figure 8 As shown, it includes the following steps:

[0065] S1: Use sulfate pulp to make kraft paper airbags, and attach the kraft paper airbags to the back of tube segments 1, 4, and 5.

[0066] Each ring of tunnel segments in the shield tunnel design is composed of 5 segments. The top segment is segment 1, the left and right sides are segments 2 and 3 respectively, and the bottom two segments are segments 4 and 5 respectively.

[0067] S101: Making Kraft Paper Airbags:

[0068] Obtain the tube segment design parameters and production speed to determine the required speed for kraft paper airbags, and determine the required amount of sulfate pulp. Produce sulfate pulp, inject the sulfate pulp into a mold, and form it into kraft paper airbags:

[0069] S102: Attach the kraft paper airbag to the outer side of the tube segment:

[0070] Remove the finished kraft paper airbag in its original state, apply glue to the outside of the tube segment, and attach the kraft paper airbag to the outside of the tube segment, ensuring that the grouting hole on the tube segment coincides with the opening of the kraft paper airbag.

[0071] After the glue dries, spray water vapor onto the kraft paper airbag to soften it, fold the kraft paper airbag and store it, and then store the tube in a rainproof place for later use.

[0072] The tubes for attaching the kraft paper airbag should be tubes No. 1, No. 4, and No. 5.

[0073] S2: As the tunnel boring machine advances, grouting is immediately injected into compartment 1 through the grouting holes after the segments are assembled.

[0074] The tunnel boring machine was advanced normally, and the segment assembly and bolt installation were completed. Immediately after the segment assembly, grout was injected into the No. 1 compartment in the kraft paper airbag behind the No. 1 segment through the grouting hole on the No. 1 segment. Grouting was stopped immediately after the grout pressure reached 0.2MPa.

[0075] The grouting operation time for compartment 1 shall not exceed 5 minutes;

[0076] S3: Grouting is performed on compartments 4 and 5 through the grouting holes;

[0077] After the grouting of compartment 1 is completed, grouting is immediately injected into compartments 4 and 5 inside the kraft paper air bladders behind the No. 4 and No. 5 tube segments through the grouting holes on the No. 4 and No. 5 tube segments. Grouting is stopped immediately after the grout pressure in the compartment reaches 0.2MPa.

[0078] The grouting operation time for compartments 4 and 5 shall not exceed 5 minutes;

[0079] S4: Pressure grouting is performed on compartments 2 and 3 through the grouting holes to fill the voids.

[0080] After the grouting of compartments 4 and 5 is completed, grouting is immediately injected into compartments 2 and 3 behind the segments through the grouting holes on segments 2 and 3. Grouting is stopped when the grout pressure in the compartments reaches and stabilizes at 0.2 MPa. The grout pressure in compartments 2 and 3 needs to be continuously monitored to ensure that it is not lower than 5 minutes. If the grout pressure drops during this period, grout needs to be added immediately until the grout pressure is maintained at 0.2 MPa.

[0081] If the grout pressure cannot reach or be maintained at 0.2 MPa, grouting should be stopped. After the aforementioned single-component grout has set, cement grout and water glass should be mixed at a volume ratio of 1:1 and injected through the grouting hole.

[0082] S5: To address the volume shrinkage issue after grout solidification, secondary grouting is performed through the grouting holes to replenish the grout.

[0083] After the grout solidifies, if cavities are found due to grout loss, the cement grout and water glass are mixed at a volume ratio of 1:1 and injected through the grouting holes of pipe segments No. 2 and No. 3 at a pressure of 0.4 MPa to fill the cavities caused by grout loss and to fill the gaps caused by the solidification and shrinkage of the grout in the kraft paper airbag.

[0084] As an optimization, the specific manufacturing method of the kraft paper airbag in S101 is as follows:

[0085] S101-1: Production of sulfate pulp, a raw material for kraft paper:

[0086] A chemical agent is pre-prepared, consisting of 1.0–1.1 mol / L sodium hydroxide and 0.2 mol / L sodium sulfide. The pH value of the resulting chemical agent is between 13.6 and 14.0 to meet the requirements. The papermaking raw materials and the chemical agent are placed together in a digester and kept at 170°C–175°C for 90 minutes to decompose the lignin. After spraying, steam recovery, washing, and filtration, the resulting pulp is the desired sulfate pulp.

[0087] The papermaking raw material is waste paper pulp or a variety of fiber raw materials, including wood, bamboo, rice straw, stalks, wheat straw, cotton and hemp, and one or more of these are used in combination.

[0088] S101-2: Assemble and adjust the kraft paper airbag forming mold according to the following steps:

[0089] According to the size of the pipe segment, a pipe segment-shaped double-layer clamp mold is made. The inside of the mold is a high-temperature resistant inflatable airbag mold made of rubber, and the outside is an iron mold. It is ensured that the distance between the inner airbag mold and the outer iron mold is equal and 1.0mm to 1.2mm after inflation, so as to ensure that the thickness of the formed kraft paper airbag is between 1.0mm and 1.2mm. A large hole is made on the iron mold on the side to be attached to the pipe segment. The position of the hole corresponds to the grouting hole on the pipe segment, which serves as a channel for water vapor to be discharged and pulp to be injected.

[0090] The outer iron mold should consist of two symmetrical parts, which are assembled by locking buckles when forming the kraft paper airbag.

[0091] S101-3: Molded Kraft Paper Airbag

[0092] The prepared sulfate pulp is injected into the cavity between the inner and outer molds. The inner rubber air bladder mold is inflated to form the pulp and pressurize it to expel moisture. The mold is then heated to 70℃~80℃ to dry and shape the kraft paper air bladder. No pulp should remain at the opening of the outer iron mold during the injection of sulfate pulp and drying process.

[0093] S101-4: Remove the kraft paper airbag:

[0094] Empty the gas from the internal airbag mold and open the external iron mold. Remove the finished kraft paper airbag in its original shape. The environment in which the kraft paper airbag is removed should be kept at a temperature of no less than 40°C and a relative humidity of no more than 15% to maintain the shape of the kraft paper airbag.

[0095] As an optimization, the formed kraft paper airbag should also meet the following performance requirements:

[0096] 1) The inflation pressure resistance of the kraft paper airbag shall not be less than 0.35MPa: Use an air compressor to pump air into the kraft paper airbag through the injection hole on the tube segment, monitor the air pressure inside the kraft paper airbag, and continue to pump air into the kraft paper airbag until the kraft paper airbag is destroyed. It is required that no air leakage occurs on the surface and at the bonding point of the kraft paper airbag before the air pressure reaches 0.3MPa. When the kraft paper airbag completely loses its airtightness and is destroyed, the peak air pressure inside the kraft paper airbag shall not be less than 0.35MPa.

[0097] 2) Water resistance: Water is injected into the kraft paper air bladder through the grouting holes on the pipe segment until the water pressure reaches 0.25MPa, and the timing begins. The time when obvious leakage occurs shall not be earlier than 15 minutes.

[0098] 3) To maintain the slurry capacity, pressure slurry is injected into the kraft paper air bladder through the slurry injection hole on the tube. Timing starts after the slurry pressure reaches 0.25MPa. The kraft paper air bladder will not be destroyed within 15 minutes.

[0099] As an optimization, the grout injected into compartment 1 in step S2 is a single-liquid grout with added accelerator. The specific mass ratio of the components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29. At the same time, 3% of the cement mass of accelerator needs to be added. The performance requirements of the grout are: consolidation shrinkage rate not exceeding 5%, initial setting time 1-5 minutes, final setting time 5-12 minutes, 24-hour consolidation strength not less than 0.6 MPa, and 28-day consolidation strength not less than 2.1 MPa.

[0100] The quick-setting agent is a powder prepared by mixing alumina clinker, sodium carbonate, and quicklime in a mass ratio of 1:0.8:0.3-0.5.

[0101] The slurry can be treated with 2 kg of calcium chloride per 1000 kg of slurry as an early strength agent.

[0102] As an optimization, the grout injected into compartments 4 and 5 in step S3 is a single-liquid grout with added accelerator. The specific mass ratio of the components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29. At the same time, 3% of the cement mass of accelerator needs to be added. The performance requirements of the grout are: consolidation shrinkage rate not exceeding 5%, initial setting time 1-5 minutes, final setting time 5-12 minutes, 24-hour consolidation strength not less than 0.6 MPa, and 28-day consolidation strength not less than 2.1 MPa.

[0103] The quick-setting agent is a powder made of alumina clinker, sodium carbonate, and quicklime in a mass ratio of 1:0.8:0.3 to 0.5.

[0104] As an optimization, the grout injected into compartments 2 and 3 in step S4 is a single-liquid grout with added accelerator. The specific mass ratio of the components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29. At the same time, 3% of the cement mass of accelerator needs to be added. The performance requirements of the grout are: consolidation shrinkage rate not exceeding 5%, initial setting time 1-5 minutes, final setting time 5-12 minutes, 24-hour consolidation strength not less than 0.6 MPa, and 28-day consolidation strength not less than 2.1 MPa.

[0105] The quick-setting agent is a powder made of alumina clinker, sodium carbonate, and quicklime in a mass ratio of 1:0.8:0.3 to 0.5.

[0106] As an optimization, if the number of segments per ring is not 5:

[0107] The method for selecting the tunnel segments for attaching kraft paper airbags to the back is as follows: first select one segment at the top of the tunnel to attach the kraft paper airbag, and then select one segment every other segment for attaching the kraft paper airbag.

[0108] The grouting construction sequence for each compartment is as follows: first construct the top compartment of the tunnel, then construct the bottom compartment, first construct the compartment inside the kraft paper airbag, and then construct the other compartments.

[0109] The method for selecting the type of grout injected into each compartment is as follows: the compartment at the top of the tunnel uses the grout injected into compartment 1 in step S2; the compartment at the bottom of the tunnel uses the grout injected into compartments 4 and 5 in step S3; and the compartments behind the tunnel lining walls on both sides use the grout injected into compartments 2 and 3 in step S4.

[0110] The above is a specific embodiment of the present invention, but the features of the present invention are not limited thereto. Numerous specific details, such as various parameter limitations and a detailed sequence of steps, are described in the specification provided herein. However, embodiments of the present invention may also be practiced without following some of the requirements herein. Similarly, the steps may be performed out of order or only some of the steps may be performed. Any simple modifications to the steps, parameters, and components based on the present invention are within the scope of protection of the present invention.

Claims

1. A compartmentalized grouting method for enhancing grouting control behind shield tunnel walls, characterized in that: The method includes the following steps: S1: Use sulfate pulp to make kraft paper airbags, and attach the kraft paper airbags to the back of tube segments 1, 4, and 5. Each ring of tunnel segments in the shield tunnel design is composed of 5 segments. The top segment is segment 1, the left and right sides are segments 2 and 3 respectively, and the bottom two segments are segments 4 and 5 respectively. S101: Assemble and debug the kraft paper airbag forming mold: According to the size of the pipe segment, a pipe segment-shaped double-layer clamp mold is made. The inside of the mold is a high-temperature resistant inflatable airbag mold made of rubber, and the outside is an iron mold. It is ensured that the distance between the inner airbag mold and the outer iron mold is equal and 1.0mm~1.2mm after inflation, so as to ensure that the thickness of the formed kraft paper airbag is between 1.0mm and 1.2mm. A large hole is made on the iron mold on the side to be attached to the pipe segment. The position of the hole corresponds to the grouting hole on the pipe segment, which serves as a channel for water vapor to be discharged and pulp to be injected. The external iron mold consists of an upper part and a lower part, which are assembled by locking buckles when forming the kraft paper airbag; S102: Making Kraft Paper Airbags: Obtain the design parameters and production speed of the tube segments, determine the required speed of the kraft paper airbags, and determine the required amount of sulfate pulp. Produce sulfate pulp, inject the prepared sulfate pulp into the cavity between two clamp-type molds, inflate the internal rubber airbag mold, so that the pulp is formed and pressurized to expel water, and then heat the mold to 70℃~80℃ to dry and shape the kraft paper airbags. No pulp should remain at the opening of the external iron mold during the injection and drying process. S103: Remove the kraft paper airbag: The gas inside the internal airbag mold is emptied, and the external iron mold is opened. The finished kraft paper airbag is removed in its original state. The ambient temperature of the kraft paper airbag should not be lower than 40°C and the relative humidity of the air should not exceed 15% to maintain the shape of the kraft paper airbag. S104: Attach the kraft paper airbag to the outside of the tube segment: Apply glue to the outside of the pipe segment, attach the kraft paper airbag to the outside of the pipe segment, and ensure that the grouting hole on the pipe segment coincides with the opening of the kraft paper airbag. After the glue dries, spray water vapor onto the kraft paper airbag to soften it, fold the kraft paper airbag and store it, and then store the tube in a rainproof place for later use. The tubes for attaching the kraft paper airbag should be tubes No. 1, No. 4, and No.

5. S2: As the tunnel boring machine advances, grouting is immediately injected into compartment 1 through the grouting holes after the segments are assembled. The tunnel boring machine was advanced normally, and the segment assembly and bolt installation were completed. Immediately after the segment assembly, grout was injected into the No. 1 compartment in the kraft paper airbag behind the No. 1 segment through the grouting hole on the No. 1 segment. Grouting was stopped immediately after the grout pressure reached 0.2MPa. The grouting operation time for compartment 1 shall not exceed 5 minutes; S3: Grouting is performed on compartments 4 and 5 through the grouting holes; After the grouting of compartment 1 is completed, grouting is immediately injected into compartments 4 and 5 inside the kraft paper air bladders behind the No. 4 and No. 5 tube segments through the grouting holes on the No. 4 and No. 5 tube segments. Grouting is stopped immediately after the grout pressure in the compartment reaches 0.2MPa. The grouting operation time for compartments 4 and 5 shall not exceed 5 minutes; S4: Pressure grouting is performed on compartments 2 and 3 through the grouting holes to fill the voids. After the grouting of compartments 4 and 5 is completed, grouting is immediately injected into compartments 2 and 3 behind the segments through the grouting holes on segments 2 and 3. Grouting is stopped when the grout pressure in the compartments reaches and stabilizes at 0.2 MPa. The grout pressure in compartments 2 and 3 needs to be continuously monitored to ensure that it is not lower than 5 minutes. If the grout pressure drops during this period, grout needs to be added immediately until the grout pressure is maintained at 0.2 MPa. If the grout pressure cannot reach or be maintained at 0.2 MPa, grouting should be stopped. After the single-component grout has set, the cement grout and water glass should be mixed at a volume ratio of 1:1 and injected through the grouting hole. S5: To address the volume shrinkage issue after grout solidification, secondary grouting is performed through the grouting holes to replenish the grout. After the grout solidifies, if grout loss is found to form a cavity, the cement grout and water glass are mixed at a volume ratio of 1:1 and injected through the grouting holes of pipe segment No. 2 and pipe segment No. 3 at a pressure of 0.4MPa to fill the cavity caused by grout loss and to fill the gap caused by the solidification shrinkage of the grout in the kraft paper air bladder.

2. The compartmentalized grouting method for enhancing grouting control behind shield tunnel walls as described in claim 1, characterized in that: The specific method for preparing sulfate pulp in S1 is as follows: A chemical agent is pre-prepared, consisting of 1.0~1.1 mol / L sodium hydroxide and 0.2 mol / L sodium sulfide. The pH value of the resulting chemical agent is between 13.6 and 14.0 to meet the requirements. The papermaking raw materials and the chemical agent are placed together in a digester and kept at 170℃~175℃ for 90 minutes to decompose the lignin. After spraying, steam recovery, washing, and filtration, the resulting pulp is the desired sulfate pulp. The papermaking raw materials are waste paper pulp or a variety of fiber raw materials, including wood, bamboo, rice straw, stalks, wheat straw, cotton and hemp, and one or more of these are used in combination.

3. The compartmentalized grouting method for enhancing grouting control behind shield tunnel walls as described in claim 2, characterized in that: The formed kraft paper airbags should also meet the following performance requirements: 1) The inflation pressure resistance of the kraft paper airbag shall not be less than 0.35MPa: Use an air compressor to pump air into the kraft paper airbag through the injection hole on the tube segment, monitor the air pressure inside the kraft paper airbag, and continue to pump air into the kraft paper airbag until the kraft paper airbag is destroyed. It is required that no air leakage occurs on the surface and at the bonding point of the kraft paper airbag before the air pressure reaches 0.3MPa. When the kraft paper airbag completely loses its airtightness and is destroyed, the peak air pressure inside the kraft paper airbag shall not be less than 0.35MPa. 2) Water resistance: Water is injected into the kraft paper air bladder through the grouting holes on the pipe segment until the water pressure reaches 0.25 MPa, and the timing begins. The time when obvious water leakage occurs must not be earlier than 15 minutes. 3) To maintain the slurry capacity, pressure slurry is injected into the kraft paper air bladder through the slurry injection hole on the tube. Timing starts after the slurry pressure reaches 0.25MPa. The kraft paper air bladder will not be destroyed within 15 minutes.

4. The compartmentalized grouting method for enhancing grouting control behind shield tunnel walls as described in claim 1, characterized in that: In step S2, the grout injected into compartment 1 is a single-component grout with added quick-setting agent. The specific mass ratio of the components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:

29. At the same time, 3% quick-setting agent by mass of cement needs to be added. The performance requirements of the grout are: consolidation shrinkage rate not exceeding 5%, initial setting time 1-5 minutes, final setting time 5-12 minutes, 24-hour consolidation strength not less than 0.6 MPa, and 28-day consolidation strength not less than 2.1 MPa. The quick-setting agent is a powder prepared by mixing alumina clinker, sodium carbonate, and quicklime in a mass ratio of 1:0.8:0.3~0.

5. The slurry can be treated with 2 kg of calcium chloride per 1000 kg of slurry as an early strength agent.

5. The compartmentalized grouting method for enhancing grouting control behind shield tunnel walls as described in claim 1, characterized in that: In step S3, the grout injected into compartments 4 and 5 is a single-component grout with added accelerator. The specific mass ratio of the components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:

29. At the same time, 3% of the cement mass of accelerator needs to be added. The performance requirements of the grout are: consolidation shrinkage rate not exceeding 5%, initial setting time 1~5 minutes, final setting time 5~12 minutes, 24-hour consolidation strength not less than 0.6 MPa, and 28-day consolidation strength not less than 2.1 MPa. The quick-setting agent is a powder made of alumina clinker, sodium carbonate, and quicklime in a mass ratio of 1:0.8:0.3~0.

5.

6. The compartmentalized grouting method for enhancing grouting control behind shield tunnel walls as described in claim 1, characterized in that: In step S4, the grout injected into compartments 2 and 3 is a single-component grout with added accelerator. The specific mass ratio of the components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:

29. At the same time, 3% of the cement mass of accelerator needs to be added. The performance requirements of the grout are: consolidation shrinkage rate not exceeding 5%, initial setting time 1~5 minutes, final setting time 5~12 minutes, 24-hour consolidation strength not less than 0.6MPa, and 28-day consolidation strength not less than 2.1MPa. The quick-setting agent is a powder made of alumina clinker, sodium carbonate, and quicklime in a mass ratio of 1:0.8:0.3~0.

5.

7. The compartmentalized grouting method for enhancing grouting control behind shield tunnel walls as described in claim 1, characterized in that: If the number of segments per ring is not 5: The method for selecting the tunnel segments for attaching kraft paper airbags to the back is as follows: first select one segment at the top of the tunnel to attach the kraft paper airbag, and then select one segment every other segment for attaching the kraft paper airbag. The grouting construction sequence for each compartment is as follows: first construct the top compartment of the tunnel, then construct the bottom compartment, first construct the compartment inside the kraft paper airbag, and then construct the other compartments. The method for selecting the type of grout injected into each compartment is as follows: the compartment at the top of the tunnel uses the grout injected into compartment 1 in step S2; the compartment at the bottom of the tunnel uses the grout injected into compartments 4 and 5 in step S3; and the compartments behind the tunnel lining walls on both sides use the grout injected into compartments 2 and 3 in step S4.

Images