Cabin-separated grouting method for strengthening shield tunnel wall back grouting control

Abstract

The invention relates to a sub-cabin grouting method for enhancing shield tunnel wall back grouting control, which comprises the following steps: S1, making kraft paper airbags by using sulfate paper pulp, and adhering the kraft paper airbags to the backs of a No.1 duct piece, a No.4 duct piece and a No.5 duct piece; s2, along with shield tunneling, grouting is conducted on the first cabin immediately through grouting holes after the duct pieces are assembled; s3, grouting is conducted on the fourth cabin and the fifth cabin through grouting holes; s4, pressure grouting is conducted on the second cabin and the third cabin through the grouting holes, and gaps are filled; and S5, according to the volume shrinkage condition after the grout is solidified, secondary grouting is conducted through the grouting holes to supplement the grout. According to the method, the shield tail gap is divided into a plurality of cabins through the inner space of the kraft paper air bag and the air bag interval space for duct piece wall back grouting construction, and control over the shield tunnel wall back grouting process and slurry solidification and diffusion can be effectively enhanced by means of the retentivity of the kraft paper air bag to slurry; the shield posture and the duct piece position are adjusted and controlled by adjusting the grouting pressure of all the cabins, slurry loss and duct piece floating are effectively prevented through grouting of the closed cabins at the tops of the duct pieces, the compactness is guaranteed, and the guarantee degree of the grouting construction quality is enhanced.

Description

Technical Field

[0001] The invention relates to the field of shield tunnel wall back grouting, and in particular to a compartment grouting method for strengthening shield tunnel wall back grouting control. Background Art

[0002] With the rapid development of urban infrastructure construction, the construction volume of urban underground tunnels such as subways is large, and blasting is mostly prohibited in urban areas. Shield tunnels have the advantages of small impact on the environment, good stratum adaptability, high degree of mechanization, and fast construction speed. Soil shield and rock TBM are widely used in urban underground tunnel construction. In order to smoothly advance the shield machine, the inner diameter of the shield shell needs to be larger than the outer diameter of the segment. In addition, the thickness of the shield shell and the existence of over-excavation make the cutter head excavation diameter larger than the outer diameter of the segment during shield excavation construction, resulting in the formation of the shield tail gap. At present, back-wall grouting is often used in shield construction to fill the shield tail gap. Back-wall grouting plays an important role in fixing the segment position, providing stress conditions for the segment, and controlling stratum deformation during shield construction. These key roles often control whether the shield can be smoothly advanced. Therefore, in the process of shield construction, segment lining and back-wall grouting, as one of the three major elements of shield construction, play a decisive role in the quality of shield construction.

[0003] At present, the grouting behind the wall is mainly divided into tail grouting and segment grouting according to the grouting position, and is mainly divided into synchronous grouting and secondary grouting according to the injection time. The injected slurry is mainly divided into single liquid slurry and double liquid slurry. In the process of grouting behind the wall, due to improper construction, problems such as segment floating, surface collapse or uplift, and segment and bolt damage often occur. To improve the quality of grouting behind the wall, the current consensus is to strengthen the control of grouting construction, and to achieve the controllable and improved quality of grouting behind the wall by strengthening the control of grouting material configuration and grouting process. However, there are no clear specifications for grouting process, grouting pressure, slurry formula, etc., and the simulation research on slurry injection and diffusion process and the control method of grouting behind the wall are still in the exploratory stage. In view of this, it is necessary to design a grouting method that can strengthen the control and management of shield tunnel wall grouting material configuration and grouting process, improve the slurry density of grouting behind the wall, and prevent problems such as segment floating. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a compartment grouting method which strengthens the control of both the preparation of grouting slurry materials and the grouting process of the back grouting of the shield tunnel wall.

[0005] To achieve the above object, the present invention adopts the following technical scheme: a compartment grouting method for strengthening the back grouting control of the shield tunnel wall, as shown in the attached Figure 1 ~Attached Figure 8 As shown, the following steps are included:

[0006] S1: Use kraft pulp to make kraft paper airbags, and stick the kraft paper airbags behind the No. 1, No. 4 and No. 5 pipe segments;

[0007] Each ring of shield tunnel segments is designed to be assembled from 5 segments, with the top segment being segment 1, the left and right sides being segments 2 and 3, and the bottom two segments being segments 4 and 5.

[0008] S101: Making kraft paper airbags:

[0009] Obtain the segment design parameters and production speed, obtain the demand speed of kraft paper airbags, obtain the demand for kraft pulp, produce kraft pulp, inject kraft pulp into the mold, and form it into kraft paper airbags:

[0010] S102: Paste the kraft paper airbag on the outside of the pipe segment:

[0011] Remove the prepared kraft paper airbag as a whole, apply glue on the outside of the pipe segment, stick the kraft paper airbag on 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;

[0012] After the glue is dry, spray water vapor to the kraft paper airbag to soften it, fold the kraft paper airbag and store it, then store the pipe segment away from rain for later use;

[0013] The tube segments for pasting the kraft paper airbags should be No. 1 tube segment, No. 4 tube segment, and No. 5 tube segment;

[0014] S2: As the shield advances, grouting is immediately performed into the No. 1 compartment through the grouting holes after the segments are assembled:

[0015] The shield machine is advanced normally, and the segment assembly and bolt installation are completed. Immediately after the segment assembly, grouting is 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. When the grouting pressure reaches 0.2MPa, the grouting is stopped immediately.

[0016] The grouting operation time of the No. 1 compartment shall not exceed 5 minutes;

[0017] S3: Grouting of cabin No. 4 and cabin No. 5 through the grouting holes;

[0018] After the grouting of cabin No. 1 is completed, grouting is immediately carried out through the grouting holes on the No. 4 and No. 5 segments to the No. 4 and No. 5 cabins in the kraft paper airbags behind the No. 4 and No. 5 segments. When the grouting pressure in the cabin reaches 0.2MPa, the grouting is stopped immediately.

[0019] The grouting operation time of the No. 4 and No. 5 compartments shall not exceed 5 minutes;

[0020] S4: Pressure grouting is performed on cabins 2 and 3 through the grouting holes to fill the gaps:

[0021] After the grouting of compartments 4 and 5 is completed, grouting is immediately carried out through the grouting holes on the 2nd and 3rd segments to the compartments 2 and 3 behind the segments. The grouting is stopped after the slurry pressure in the compartments reaches and stabilizes at 0.2MPa. The slurry pressure in compartments 2 and 3 needs to be continuously monitored for not less than 5 minutes. If the slurry pressure drops during this period, the slurry needs to be replenished immediately until the slurry pressure is maintained at 0.2MPa.

[0022] If the slurry pressure cannot reach or remain at 0.2MPa, the grouting should be stopped. After the single-liquid slurry injected above has finally set, the cement slurry and water glass are mixed in a volume ratio of 1:1 and then injected through the grouting hole;

[0023] S5: According to the volume shrinkage of the slurry after solidification, secondary grouting is carried out through the grouting holes to replenish the slurry:

[0024] After the slurry solidifies, if slurry loss is found to form cavities, mix cement slurry and water glass in a volume ratio of 1:1 and inject it through the grouting holes of segments 2 and 3 at a pressure of 0.4 MPa to make up for the cavities caused by the slurry loss and fill the gaps caused by the consolidation and shrinkage of the slurry in the kraft paper airbag.

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

[0026] S101-1: Making Kraft Paper Raw Material Sulfate Pulp:

[0027] A chemical agent is prepared in advance, the composition of which is 1.0-1.1 mol / L sodium hydroxide and 0.2 mol / L sodium sulfide, and the pH value of the obtained chemical agent is between 13.6 and 14.0 to meet the requirements. The papermaking raw materials and the chemical agent are put into a digester together, and kept at 170°C-175°C for 90 minutes to decompose the lignin. Then, the pulp obtained by spraying, recovering steam, washing and filtering is the required kraft pulp.

[0028] The papermaking raw material is waste paper pulp or a variety of fiber raw materials, and the fiber raw materials are wood, bamboo, straw, stalks, wheat straw, cotton and linen, and one or more of them are mixed and used;

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

[0030] A double-layer clamp-type mold of a similar segment shape is made according to the size of the segment. 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 iron outer mold after inflation is equal and 1.0mm-1.2mm, so as to ensure that the thickness of the formed kraft paper airbag is between 1.0mm and 1.2mm. A large hole is opened on the iron mold on the side where the segment will be attached. The hole position corresponds to the grouting hole on the segment, which serves as a channel for water vapor discharge and pulp injection;

[0031] The outer iron mold should be composed 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 kraft pulp is injected into the cavity between the inner and outer molds, and the inner rubber airbag mold is inflated to shape the pulp and expel water under pressure. The mold is then heated to 70℃~80℃ to dry the kraft paper airbag and set it. During the injection and drying process of the kraft pulp, no pulp should remain at the opening of the outer iron mold.

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

[0035] Empty the gas in the inner airbag mold, open the outer iron mold, and remove the prepared kraft paper airbag as a whole. The environment for taking out the kraft paper airbag should maintain a temperature not lower than 40℃ and a relative humidity not exceeding 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 compressive strength 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 grouting holes on the pipe 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 shall occur on the surface and bonding parts 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 airbag through the grouting holes on the pipe segment until the water pressure reaches 0.25MPa and the timing starts. The time when obvious water leakage occurs shall not be earlier than 15 minutes;

[0039] 3) Maintain the slurry capacity and perform pressure grouting into the kraft paper airbag through the grouting holes on the pipe segment. Start timing after the slurry pressure reaches 0.25MPa. The kraft paper airbag will not be damaged within 15 minutes.

[0040] As an optimization, the slurry injected into the No. 1 compartment in step S2 is a single-liquid slurry with an accelerating agent added, and the mass ratio of the specific components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29, and an accelerating agent of 3% of the mass of cement needs to be added at the same time. The performance requirements of the obtained slurry are that the consolidation shrinkage rate does not exceed 5%, the initial setting time is 1 to 5 minutes, the final setting time is 5 to 12 minutes, the 24-hour consolidation strength is not less than 0.6Mpa, and the 28-day consolidation strength is not less than 2.1MPa;

[0041] The accelerating 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 added with 2kg of calcium chloride as an early strength agent per 1000kg of slurry.

[0043] As an optimization, the slurry injected into the No. 4 and No. 5 cabins in step S3 is a single-liquid slurry with an accelerated setting agent added, and the mass ratio of the specific components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29, and an accelerated setting agent of 3% of the cement mass needs to be added at the same time. The performance requirements of the obtained slurry are that the consolidation shrinkage rate does not exceed 5%, the initial setting time is 1 to 5 minutes, the final setting time is 5 to 12 minutes, the 24-hour consolidation strength is not less than 0.6Mpa, and the 28-day consolidation strength is not less than 2.1MPa;

[0044] The quick-setting agent is a powdery substance prepared by mixing alumina clinker, sodium carbonate and quicklime in a mass ratio of 1:0.8:0.3-0.5.

[0045] As an optimization, the slurry injected into the No. 2 and No. 3 cabins in step S4 is a single-liquid slurry with an accelerated setting agent added, and the mass ratio of the specific components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29, and an accelerated setting agent of 3% of the cement mass needs to be added at the same time. The performance requirements of the obtained slurry are that the consolidation shrinkage rate does not exceed 5%, the initial setting time is 1 to 5 minutes, the final setting time is 5 to 12 minutes, the 24-hour consolidation strength is not less than 0.6MPa, and the 28-day consolidation strength is not less than 2.1MPa;

[0046] The quick-setting agent is a powdery substance prepared by mixing alumina clinker, sodium carbonate and quicklime in a mass ratio of 1:0.8:0.3-0.5.

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

[0048] The method of selecting the pipe segments for pasting the kraft paper airbag on the back is: first select a piece on the top of the tunnel to paste the kraft paper airbag, and then select one piece from the other pipe segments for pasting the kraft paper airbag every other piece;

[0049] The order of grouting construction of each compartment is: first construct the compartment at the top of the tunnel, then the compartment at the bottom, first construct the compartment inside the kraft paper airbag, then construct other compartments;

[0050] The type of slurry injected into each compartment is selected as follows: the compartment at the top of the tunnel uses the slurry injected into compartment No. 1 in step S2, the compartment at the bottom of the tunnel uses the slurry injected into compartment No. 4 and compartment No. 5 in step S3, and the compartments behind the segment walls on both sides of the tunnel use the slurry injected into compartment No. 2 and compartment No. 3 in step S4.

[0051] It should be noted that the descriptions of directions such as "inside the segment" and "outside the segment" in this method all point to the center of the tunnel section.

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

[0053] The present invention provides a compartment grouting method for strengthening the control of grouting behind the shield tunnel wall. Prefabricated kraft paper air bags are pasted on the outer side of the segment lining, and the shield tail gap is divided into multiple compartments using the internal space of the kraft paper air bags and the space between the air bags. The order of grouting construction and key time nodes are arranged for each compartment, and the slurry material configuration method and the grouting construction process in each compartment are individually controlled. The slurry retention of the kraft paper air bags can effectively strengthen the control of the grouting process behind the shield tunnel wall and the solidification and diffusion of the slurry. The shield posture and the segment position are regulated by adjusting the grouting pressure of each compartment. Grouting in the closed compartment on the top of the segment can first control the segment position and ensure that the top slurry can be filled, effectively preventing the loss of slurry and the floating of the segment, ensuring the density, and enhancing the assurance of the grouting construction quality. 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 scientificity of grouting behind the shield tunnel wall, improves the slurry density of grouting behind the wall, and prevents problems such as floating of the pipe segments. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings are only used to illustrate the embodiments and are not to be considered as limiting the present invention. In addition, the same names are used for the same components throughout the accompanying drawings. In the accompanying drawings:

[0055] Figure 1 — is a simplified flow chart of the method of the present invention.

[0056] Figure 2 —Schematic diagram of making kraft paper airbag.

[0057] Figure 3 —Schematic diagram of demoulding and removing the kraft paper airbag.

[0058] Figure 4—Sketch of the kraft paper airbag.

[0059] Figure 5 —Tunnel cross-section diagram when the segments are assembled.

[0060] Figure 6 —Tunnel cross-section diagram when grouting of compartment No. 1 is completed.

[0061] Figure 7 —Tunnel cross-section diagram when grouting of compartments No. 4 and No. 5 was completed.

[0062] Figure 8 —Tunnel cross-section diagram when grouting is completed. DETAILED DESCRIPTION

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

[0064] A compartment grouting method for strengthening the grouting control of the shield tunnel wall, as shown in the attached Figure 1 ~Attached Figure 8 As shown, the following steps are included:

[0065] S1: Use kraft pulp to make kraft paper airbags, and stick the kraft paper airbags behind the No. 1, No. 4 and No. 5 pipe segments;

[0066] Each ring of shield tunnel segments is designed to be assembled from 5 segments, with the top segment being segment 1, the left and right sides being segments 2 and 3, and the bottom two segments being segments 4 and 5.

[0067] S101: Making kraft paper airbags:

[0068] Obtain the segment design parameters and production speed, obtain the demand speed of kraft paper airbags, obtain the demand for kraft pulp, produce kraft pulp, inject kraft pulp into the mold, and form it into kraft paper airbags:

[0069] S102: Paste the kraft paper airbag on the outside of the pipe segment:

[0070] Remove the prepared kraft paper airbag as a whole, apply glue on the outside of the pipe segment, stick the kraft paper airbag on 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;

[0071] After the glue is dry, spray water vapor to the kraft paper airbag to soften it, fold the kraft paper airbag and store it, then store the pipe segment away from rain for later use;

[0072] The tube segments for pasting the kraft paper airbags should be No. 1 tube segment, No. 4 tube segment, and No. 5 tube segment;

[0073] S2: As the shield advances, grouting is immediately performed into the No. 1 compartment through the grouting holes after the segments are assembled:

[0074] The shield machine is advanced normally, and the segment assembly and bolt installation are completed. Immediately after the segment assembly, grouting is 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. When the grouting pressure reaches 0.2MPa, the grouting is stopped immediately.

[0075] The grouting operation time of the No. 1 compartment shall not exceed 5 minutes;

[0076] S3: Grouting of cabin No. 4 and cabin No. 5 through the grouting holes;

[0077] After the grouting of cabin No. 1 is completed, grouting is immediately carried out through the grouting holes on the No. 4 and No. 5 segments to the No. 4 and No. 5 cabins in the kraft paper airbags behind the No. 4 and No. 5 segments. When the grouting pressure in the cabin reaches 0.2MPa, the grouting is stopped immediately.

[0078] The grouting operation time of the No. 4 and No. 5 compartments shall not exceed 5 minutes;

[0079] S4: Pressure grouting is performed on cabins 2 and 3 through the grouting holes to fill the gaps:

[0080] After the grouting of compartments 4 and 5 is completed, grouting is immediately carried out through the grouting holes on the 2nd and 3rd segments to the compartments 2 and 3 behind the segments. The grouting is stopped after the slurry pressure in the compartments reaches and stabilizes at 0.2MPa. The slurry pressure in compartments 2 and 3 needs to be continuously monitored for not less than 5 minutes. If the slurry pressure drops during this period, the slurry needs to be replenished immediately until the slurry pressure is maintained at 0.2MPa.

[0081] If the slurry pressure cannot reach or remain at 0.2MPa, the grouting should be stopped. After the single-liquid slurry injected above has finally set, the cement slurry and water glass are mixed in a volume ratio of 1:1 and then injected through the grouting hole;

[0082] S5: According to the volume shrinkage of the slurry after solidification, secondary grouting is carried out through the grouting holes to replenish the slurry:

[0083] After the slurry solidifies, if slurry loss is found to form cavities, mix cement slurry and water glass in a volume ratio of 1:1 and inject it through the grouting holes of segments 2 and 3 at a pressure of 0.4 MPa to make up for the cavities caused by the slurry loss and fill the gaps caused by the consolidation and shrinkage of the slurry in the kraft paper airbag.

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

[0085] S101-1: Making Kraft Paper Raw Material Sulfate Pulp:

[0086] A chemical agent is prepared in advance, the composition of which is 1.0-1.1 mol / L sodium hydroxide and 0.2 mol / L sodium sulfide, and the pH value of the obtained chemical agent is between 13.6 and 14.0 to meet the requirements. The papermaking raw materials and the chemical agent are put into a digester together, and kept at 170°C-175°C for 90 minutes to decompose the lignin. Then, the pulp obtained by spraying, recovering steam, washing and filtering is the required kraft pulp.

[0087] The papermaking raw material is waste paper pulp or a variety of fiber raw materials, and the fiber raw materials are wood, bamboo, straw, stalks, wheat straw, cotton and linen, and one or more of them are mixed and used;

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

[0089] A double-layer clamp-type mold of a similar segment shape is made according to the size of the segment. 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 iron outer mold after inflation is equal and 1.0mm-1.2mm, so as to ensure that the thickness of the formed kraft paper airbag is between 1.0mm and 1.2mm. A large hole is opened on the iron mold on the side where the segment will be attached. The hole position corresponds to the grouting hole on the segment, which serves as a channel for water vapor discharge and pulp injection;

[0090] The outer iron mold should be composed 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 kraft pulp is injected into the cavity between the inner and outer molds, and the inner rubber airbag mold is inflated to shape the pulp and expel water under pressure. The mold is then heated to 70℃~80℃ to dry the kraft paper airbag and set it. During the injection and drying process of the kraft pulp, no pulp should remain at the opening of the outer iron mold.

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

[0094] Empty the gas in the inner airbag mold, open the outer iron mold, and remove the prepared kraft paper airbag as a whole. The environment for taking out the kraft paper airbag should maintain a temperature not lower than 40℃ and a relative humidity not exceeding 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 compressive strength 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 grouting holes on the pipe 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 shall occur on the surface and bonding parts 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 airbag through the grouting holes on the pipe segment until the water pressure reaches 0.25MPa and the timing starts. The time when obvious water leakage occurs shall not be earlier than 15 minutes;

[0098] 3) Maintain the slurry capacity and perform pressure grouting into the kraft paper airbag through the grouting holes on the pipe segment. Start timing after the slurry pressure reaches 0.25MPa. The kraft paper airbag will not be damaged within 15 minutes.

[0099] As an optimization, the slurry injected into the No. 1 compartment in step S2 is a single-liquid slurry with an accelerating agent added, and the mass ratio of the specific components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29, and an accelerating agent of 3% of the mass of cement needs to be added at the same time. The performance requirements of the obtained slurry are that the consolidation shrinkage rate does not exceed 5%, the initial setting time is 1 to 5 minutes, the final setting time is 5 to 12 minutes, the 24-hour consolidation strength is not less than 0.6Mpa, and the 28-day consolidation strength is not less than 2.1MPa;

[0100] The accelerating 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 added with 2kg of calcium chloride as an early strength agent per 1000kg of slurry.

[0102] As an optimization, the slurry injected into the No. 4 and No. 5 cabins in step S3 is a single-liquid slurry with an accelerated setting agent added, and the mass ratio of the specific components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29, and an accelerated setting agent of 3% of the cement mass needs to be added at the same time. The performance requirements of the obtained slurry are that the consolidation shrinkage rate does not exceed 5%, the initial setting time is 1 to 5 minutes, the final setting time is 5 to 12 minutes, the 24-hour consolidation strength is not less than 0.6Mpa, and the 28-day consolidation strength is not less than 2.1MPa;

[0103] The quick-setting agent is a powdery substance prepared by mixing alumina clinker, sodium carbonate and quicklime in a mass ratio of 1:0.8:0.3-0.5.

[0104] As an optimization, the slurry injected into the No. 2 and No. 3 cabins in step S4 is a single-liquid slurry with an accelerated setting agent added, and the mass ratio of the specific components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29, and an accelerated setting agent of 3% of the cement mass needs to be added at the same time. The performance requirements of the obtained slurry are that the consolidation shrinkage rate does not exceed 5%, the initial setting time is 1 to 5 minutes, the final setting time is 5 to 12 minutes, the 24-hour consolidation strength is not less than 0.6MPa, and the 28-day consolidation strength is not less than 2.1MPa;

[0105] The quick-setting agent is a powdery substance prepared by mixing alumina clinker, sodium carbonate and quicklime in a mass ratio of 1:0.8:0.3-0.5.

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

[0107] The method of selecting the pipe segments for pasting the kraft paper airbag on the back is: first select a piece on the top of the tunnel to paste the kraft paper airbag, and then select one piece from the other pipe segments for pasting the kraft paper airbag every other piece;

[0108] The order of grouting construction of each compartment is: first construct the compartment at the top of the tunnel, then the compartment at the bottom, first construct the compartment inside the kraft paper airbag, then construct other compartments;

[0109] The type of slurry injected into each compartment is selected as follows: the compartment at the top of the tunnel uses the slurry injected into compartment No. 1 in step S2, the compartment at the bottom of the tunnel uses the slurry injected into compartment No. 4 and compartment No. 5 in step S3, and the compartments behind the segment walls on both sides of the tunnel use the slurry injected into compartment No. 2 and compartment No. 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. In the description provided herein, a large number of specific details are described, such as many parameter restrictions and detailed step sequences. However, the embodiments of the present invention may also be practiced without following some of the requirements. Similarly, the steps may not be performed in the described order or only some of the steps may be performed. Any simple changes such as adjustments of steps, parameters and components based on the present invention are within the scope of protection of the present invention.

Claims

1. A compartment grouting method for strengthening the back grouting control of shield tunnel wall, characterized in that: The method comprises the following steps: S1: Use kraft pulp to make kraft paper airbags, and stick the kraft paper airbags behind the No. 1, No. 4 and No. 5 pipe segments; Each ring of shield tunnel segments is designed to be assembled from 5 segments, with the top segment being segment 1, the left and right sides being segments 2 and 3, and the bottom two segments being segments 4 and 5. S101: Making kraft paper airbags: Obtain the segment design parameters and production speed, obtain the demand speed of kraft paper airbags, obtain the demand for kraft pulp, produce kraft pulp, inject kraft pulp into the mold, and form it into kraft paper airbags: S102: Paste the kraft paper airbag on the outside of the pipe segment: Remove the prepared kraft paper airbag as a whole, apply glue on the outside of the pipe segment, stick the kraft paper airbag on 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 is dry, spray water vapor to the kraft paper airbag to soften it, fold the kraft paper airbag and store it, then store the pipe segment away from rain for later use; The tube segments for pasting the kraft paper airbags should be No. 1 tube segment, No. 4 tube segment, and No. 5 tube segment; S2: As the shield advances, grouting is immediately performed into the No. 1 compartment through the grouting holes after the segments are assembled: The shield machine is advanced normally, and the segment assembly and bolt installation are completed. Immediately after the segment assembly, grouting is 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. When the grouting pressure reaches 0.2MPa, the grouting is stopped immediately. The grouting operation time of the No. 1 compartment shall not exceed 5 minutes; S3: Grouting of cabin No. 4 and cabin No. 5 through the grouting holes; After the grouting of cabin No. 1 is completed, grouting is immediately carried out through the grouting holes on the No. 4 and No. 5 segments to the No. 4 and No. 5 cabins in the kraft paper airbags behind the No. 4 and No. 5 segments. When the grouting pressure in the cabin reaches 0.2MPa, the grouting is stopped immediately. The grouting operation time of the No. 4 and No. 5 compartments shall not exceed 5 minutes; S4: Pressure grouting is performed on cabins 2 and 3 through the grouting holes to fill the gaps: After the grouting of compartments 4 and 5 is completed, grouting is immediately carried out through the grouting holes on the 2nd and 3rd segments to the compartments 2 and 3 behind the segments. The grouting is stopped after the slurry pressure in the compartments reaches and stabilizes at 0.2MPa. The slurry pressure in compartments 2 and 3 needs to be continuously monitored for not less than 5 minutes. If the slurry pressure drops during this period, the slurry needs to be replenished immediately until the slurry pressure is maintained at 0.2MPa. If the slurry pressure cannot reach or remain at 0.2MPa, the grouting should be stopped. After the single-liquid slurry injected above has finally set, the cement slurry and water glass are mixed in a volume ratio of 1:1 and then injected through the grouting hole; S5: According to the volume shrinkage of the slurry after solidification, secondary grouting is carried out through the grouting holes to replenish the slurry: After the slurry solidifies, if slurry loss is found to form cavities, mix cement slurry and water glass in a volume ratio of 1:1 and inject it through the grouting holes of segments 2 and 3 at a pressure of 0.4 MPa to make up for the cavities caused by the slurry loss and fill the gaps caused by the consolidation and shrinkage of the slurry in the kraft paper airbag.

2. The compartment grouting method for strengthening the rear grouting control of the shield tunnel wall according to claim 1 is characterized in that: The specific production method of the kraft paper airbag in S101 is: S101-1: Making Kraft Paper Raw Material Sulfate Pulp: A chemical agent is prepared in advance, the composition of which is 1.0-1.1 mol / L sodium hydroxide and 0.2 mol / L sodium sulfide, and the pH value of the obtained chemical agent is between 13.6 and 14.0 to meet the requirements. The papermaking raw materials and the chemical agent are put into a digester together, and kept at 170°C-175°C for 90 minutes to decompose the lignin. Then, the pulp obtained by spraying, recovering steam, washing and filtering is the required kraft pulp. The papermaking raw material is waste paper pulp or a variety of fiber raw materials, and the fiber raw materials are wood, bamboo, straw, stalks, wheat straw, cotton and linen, and one or more of them are mixed and used; S101-2: Assemble and debug the kraft paper airbag forming mold according to the following steps: A double-layer clamp-type mold of a similar segment shape is made according to the size of the segment. 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 iron outer mold after inflation is equal and 1.0mm-1.2mm, so as to ensure that the thickness of the formed kraft paper airbag is between 1.0mm and 1.2mm. A large hole is opened on the iron mold on the side where the segment will be attached. The hole position corresponds to the grouting hole on the segment, which serves as a channel for water vapor discharge and pulp injection; The outer iron mold should be composed of two symmetrical parts, which are assembled by locking buckles when forming the kraft paper airbag; S101-3: Molded kraft paper airbag: The prepared kraft pulp is injected into the cavity between the inner and outer molds, and the inner rubber airbag mold is inflated to shape the pulp and expel water under pressure. The mold is then heated to 70℃~80℃ to dry the kraft paper airbag and set it. During the injection and drying process of the kraft pulp, no pulp should remain at the opening of the outer iron mold. S101-4: Remove the kraft paper airbag: Empty the gas in the inner airbag mold, open the outer iron mold, and remove the prepared kraft paper airbag as a whole. The environment for taking out the kraft paper airbag should maintain a temperature not lower than 40℃ and a relative humidity not exceeding 15% to maintain the shape of the kraft paper airbag; 3. The compartment grouting method for strengthening the back grouting control of the shield tunnel wall as claimed in claim 2 is characterized by: The formed kraft paper airbag should also meet the following performance requirements: 1) The inflation compressive strength 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 grouting holes on the pipe 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 shall occur on the surface and bonding parts 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 airbag through the grouting holes on the pipe segment until the water pressure reaches 0.25MPa and the timing starts. The time when obvious water leakage occurs shall not be earlier than 15 minutes; 3) Maintain the slurry capacity and perform pressure grouting into the kraft paper airbag through the grouting holes on the pipe segment. Start timing after the slurry pressure reaches 0.25MPa. The kraft paper airbag will not be damaged within 15 minutes.

4. The compartment grouting method for strengthening the back grouting control of the shield tunnel wall according to claim 1, characterized in that: The slurry injected into the No. 1 compartment in step S2 is a single-liquid slurry with an accelerating agent added, and the mass ratio of the specific components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29, and an accelerating agent of 3% by mass of cement needs to be added at the same time. The performance requirements of the obtained slurry are that the consolidation shrinkage rate does not exceed 5%, the initial setting time is 1 to 5 minutes, the final setting time is 5 to 12 minutes, the 24-hour consolidation strength is not less than 0.6Mpa, and the 28-day consolidation strength is not less than 2.1MPa; The accelerating 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 added with 2kg of calcium chloride as an early strength agent per 1000kg of slurry.

5. The compartment grouting method for strengthening the rear grouting control of the shield tunnel wall according to claim 1, characterized in that: The slurry injected into the No. 4 and No. 5 cabins in step S3 is a single liquid slurry with an accelerating agent added, and the mass ratio of the specific components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29, and an accelerating agent of 3% of the mass of cement needs to be added at the same time. The performance requirements of the obtained slurry are that the consolidation shrinkage rate does not exceed 5%, the initial setting time is 1 to 5 minutes, the final setting time is 5 to 12 minutes, the 24-hour consolidation strength is not less than 0.6Mpa, and the 28-day consolidation strength is not less than 2.1MPa; The quick-setting agent is a powdery substance prepared by mixing alumina clinker, sodium carbonate and quicklime in a mass ratio of 1:0.8:0.3-0.

5.

6. The compartment grouting method for strengthening the back grouting control of the shield tunnel wall according to claim 1, characterized in that: The slurry injected into the No. 2 and No. 3 cabins in step S4 is a single-liquid slurry with an accelerating agent added, and the mass ratio of the specific components is: cement: fly ash: bentonite: standard sand: water = 20:20:6:25:29, and an accelerating agent of 3% of the mass of cement needs to be added at the same time. The performance requirements of the obtained slurry are that the consolidation shrinkage rate does not exceed 5%, the initial setting time is 1 to 5 minutes, the final setting time is 5 to 12 minutes, the 24-hour consolidation strength is not less than 0.6MPa, and the 28-day consolidation strength is not less than 2.1MPa; The quick-setting agent is a powdery substance prepared by mixing alumina clinker, sodium carbonate and quicklime in a mass ratio of 1:0.8:0.3-0.

5.

7. The compartment grouting method for strengthening the rear grouting control of the shield tunnel wall according to claim 1, characterized in that: If the number of segments per ring is not 5: The method of selecting the pipe segments for pasting the kraft paper airbag on the back is: first select a piece on the top of the tunnel to paste the kraft paper airbag, and then select one piece from the other pipe segments for pasting the kraft paper airbag every other piece; The order of grouting construction of each compartment is: first construct the compartment at the top of the tunnel, then the compartment at the bottom, first construct the compartment inside the kraft paper airbag, then construct other compartments; The type of slurry injected into each compartment is selected as follows: the compartment at the top of the tunnel uses the slurry injected into compartment No. 1 in step S2, the compartment at the bottom of the tunnel uses the slurry injected into compartment No. 4 and compartment No. 5 in step S3, and the compartments behind the segment walls on both sides of the tunnel use the slurry injected into compartment No. 2 and compartment No. 3 in step S4.

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