A shield tunnel deformation grouting reinforcement and deviation rectification method suitable for water-rich sand layer

Abstract

The application provides a shield tunnel deformation grouting reinforcement and deviation rectification method suitable for water-rich sand layer, which comprises the following steps: drilling a grouting hole in the stratum needing grouting through a drilling device, fixing a one-way valve and installing a sleeve valve pipe, then reinforcing the soil through high-low pressure pulse long-distance jet grouting, then performing double-liquid normal-pressure grouting through a secondary grouting hole of a pipe piece, finally lowering a grouting pipe to connect higher-pressure grouting liquid to perform double-liquid secondary grouting until the grouting is completed. In the grouting process, the grouting pressure is adjusted to expand the grouting diffusion radius and improve the grouting diffusion range; the multiple grouting procedures are adopted in combination with the reversing valve to adjust the grouting path, so that the strength of the grouting reinforcement body in the preset time is improved, the grouting wall and the counterforce wall are formed to facilitate the implementation of the deviation rectification pressure, the ability of the tunnel to resist external load is improved, and the grouting reinforcement and deviation rectification efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of shield tunneling technology, and in particular to a method for deformation grouting reinforcement and correction of shield tunnels in water-rich sand layers. Background Technology

[0002] Existing subway tunnels inevitably suffer from additional and uneven loads due to surrounding construction and long-term operation, making them prone to excessive deformation. This can lead to structural defects such as water leakage, cracking, and misalignment in the tunnel segments, seriously affecting the tunnel's construction clearance and structural stability, and endangering traffic safety. For shield tunnels experiencing deformation, soil grouting reinforcement is a commonly used treatment method.

[0003] Soil grouting reinforcement is a method that strengthens the mechanical properties of soil through secondary grouting, adjusts the distribution of soil pressure, and reduces tunnel deformation. However, existing grouting techniques are easily affected by external loads and geological conditions, leading to unsatisfactory grouting results, especially in water-rich sand layers. These layers are rich in water, have a loose structure, and are highly permeable. The size and connectivity of pores have a significant impact on grouting in sand layers, which can easily cause the following problems: 1) Uneven diffusion of the grout during permeation grouting results in poor reinforcement; 2) When the grout is diffused for reinforcement in the form of compaction, the non-uniform stress state of the sand layer will cause the grout diffusion to have a certain direction, which can easily cause overall mechanical non-uniformity of the grouting reinforcement, making it difficult to restore the tunnel segment's convergence deformation. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for deformation grouting reinforcement and correction of shield tunnels in water-rich sand layers. This reinforcement and correction method can expand the grout penetration range and improve the overall strength of the grouting reinforcement within a preset time, thereby improving the tunnel's ability to resist external loads and the grouting correction efficiency, and effectively solving the problems raised in the background art.

[0005] A method for deformation grouting reinforcement and correction of shield tunnels in water-rich sand layers includes the following steps:

[0006] S1. By monitoring multiple points with a total station, the baseline and major and minor axis lengths of the shield tunnel after deformation are recorded to obtain the segment deformation convergence, determine the shield tunnel deformation and location, and judge whether it is a single-sided lateral convergence deformation or a double-sided lateral convergence deformation of the tunnel.

[0007] S2. If the tunnel undergoes lateral convergence deformation on one side, two additional grouting holes are drilled on the shield segment using a drilling device on the deformed side. If the tunnel undergoes lateral convergence deformation on both sides, two additional grouting holes are drilled symmetrically on both sides of the tunnel.

[0008] S3, single-liquid high and low pressure pulse grouting, the grouting device adopts high and low pressure pulse grouting to perform synchronous grouting from top to bottom to the auxiliary grouting hole. During single-section grouting, if the flow meters of the two lines gradually slow down to stop or the grouting pressure reaches the final pressure, the grouting pipe is lowered and the above grouting process is repeated until the last section of grouting.

[0009] S4, dual-liquid grouting: After positioning the position of the first grouting, the second grouting is carried out by connecting the sleeve valve pipe through the secondary grouting hole of the segment. The grouting method adopts normal pressure grouting from top to bottom in stages. When the single-stage grouting pressure is gradually increased to the final pressure, the grouting is stopped. The grouting pipe is lowered down and the above grouting process is repeated until the last grouting is completed.

[0010] S5, Double-liquid secondary grouting: After step S4, continue to lower the grouting pipe and grout section by section until it is close to the tunnel segment. The grouting pressure is set at 0.7-0.8MPa, and the pressure variation range is maintained between 0.5-0.9MPa. After adjusting the reversing valve to mix the two grouts, the grout is discharged. The single grouting distance is 40cm and the interval is 45s. At the same time, the secondary grouting holes adjacent to the tunnel segment are opened for pressure relief and drainage. Several monitoring points are arranged on the monitoring section of the grouting tunnel segment. If the tunnel displacement deformation rebound reaches 2mm / h during the grouting process, the grouting is stopped and the monitoring frequency is increased until it stabilizes.

[0011] S6. After dismantling the grouting pipeline, clean up the site and continue to reinforce and correct the next deformed position.

[0012] The above-mentioned method for deformation grouting reinforcement and correction of shield tunnels applicable to water-rich sand layers, wherein step S1 specifically includes:

[0013] By monitoring multiple points with a total station to record the baseline and major and minor axis lengths of the shield tunnel after deformation, if the ratio of the tunnel segment convergence value ΔD to the tunnel diameter D exceeds 12‰, it is determined that the tunnel convergence deformation has reached the level that needs to be repaired. Further comparison of the degree of tunnel major and minor axis deformation is made, and it is determined whether the tunnel is undergoing unilateral or bilateral lateral convergence based on the degree of tunnel major and minor axis deformation.

[0014] The above-mentioned method for grouting reinforcement and correction of deformation in shield tunnels with water-rich sand layers includes step S2, in which, for lateral convergence deformation on one side or lateral convergence deformation on both sides of the tunnel, the two additional grouting holes are symmetrical about the secondary grouting holes of the segments at 30°, the drilling depth is set to 3m, the sleeve valve pipe is installed after drilling, and the one-way valve is installed on the upper part of the sleeve valve pipe.

[0015] The above-mentioned method for grouting reinforcement and correction of deformation in shield tunnels with water-rich sand layers includes the following steps: In step S3, the cement-based grout used for grouting is 42.5 grade ordinary Portland cement and XPM nano-injection agent, with a water-cement ratio of 0.5:1-0.8:1; the amount of XPM agent added is 8%-10% of the mass of the mixture, and the initial setting time is controlled at 8-10 min, and the final setting time is controlled at 30-35 min.

[0016] The total grouting length is 60cm. The grouting pressure range of the high-pressure pump is set to 2-3MPa, and the grouting pressure range of the low-pressure pump is set to 0.4-0.5MPa. The grouting frequency of alternating high-pressure and low-pressure pumps is 30 times / min. Grouting is carried out segment by segment from top to bottom. The segment length of each grouting segment is 10cm and the interval time is set to 5min.

[0017] The final pressure is determined based on the average grouting pressure of the pressure pump's built-in pressure control gauge and the grouting branch pressure gauge, and is set to 0.1-0.2 MPa.

[0018] The above-mentioned method for deformation grouting reinforcement and correction of shield tunnels in water-rich sand layers includes step S4, in which the two-component grouting uses cement-water glass grout. The cement grout is mainly composed of 42.5 grade silicate cement with a water-cement ratio of 0.5:1-0.8:1; the water glass modulus is 2.8-3.1, the concentration is 40-45Be', and the ratio of cement grout to water glass grout is 1:0.5-1:0.3. The initial setting time of the grout is controlled within 2 minutes, and the final setting time is controlled within 18 minutes.

[0019] The grouting method of dual-liquid grouting is as follows: the storage tanks of the two grouting lines are filled with cement grout and water glass grout respectively. The two grouting lines maintain the grouting pressure at 0.5-0.6MPa, keep the pressure variation range between 0.4-0.8MPa, and adjust the reversing valve to ensure that the two grouts are mixed evenly before grouting.

[0020] The above-mentioned method for grouting reinforcement and correction of deformation in shield tunnels with water-rich sand layers includes the following: for lateral convergence deformation on one side of the tunnel, the segment side needs to be reinforced on the other side of the deformation by means of two-liquid grout in step S4, and then grouting is performed on the unidirectional deformation according to steps S3-S5.

[0021] For the transverse convergence deformation on both sides of the tunnel, grouting is carried out on both sides of the deformation according to steps S3-S5.

[0022] The above-mentioned method for deformation grouting reinforcement and correction of shield tunnels in water-rich sandy layers includes a grouting device in which two grouting branches converge at the main grout outlet line. Each branch line is equipped with a storage tank, a pressure pump, a flow meter, and a pressure gauge. The pressure pump is equipped with a pressure control gauge, which can adjust the high and low pressure to set different pressure outlet lines. The flow meter and pressure gauge record real-time information of the grouting line.

[0023] The above-mentioned method for deformation grouting reinforcement and correction of shield tunnels in water-rich sand layers includes a reversing valve and a control valve in the main grouting line. The reversing valve includes a valve body, a sealing component, and a handle. The reversing valve has multiple grout inlets and outlets in the middle. The handle position can be adjusted to allow multiple grouting lines to perform independent grouting or joint grouting. The control valve controls the grouting switch of the entire grouting device.

[0024] Beneficial effects:

[0025] (1) The present invention uses a reversing valve to inject grout into the additional grouting hole with high and low pressure pulses, which can greatly expand the crack width of the sand layer, increase the channel for grout flow, enhance the penetration of grout, and increase the actual expansion area of ​​grout. In addition, the first grout uses a cement-based and XPM additive mixed grout with high strength, which can strengthen the strength of the surrounding soil and form a certain strength foundation for subsequent grouting.

[0026] (2) The present invention performs the second grouting through the secondary grouting hole of the pipe segment. The cement-water glass double liquid grout has a short setting time. Based on the first grouting solidification, the double liquid grout can quickly fill the gap of the first grout and together form an arc-shaped grout stop wall and a grouting ring reaction wall.

[0027] (3) The present invention utilizes the arc reaction wall formed by the first and second grouting solids through the final high-pressure grouting to concentrate the lateral thrust to correct the deformation of the shield tunnel.

[0028] (4) This invention solves the problem of uneven grout diffusion during grouting by using multiple grouting processes in a step-by-step manner and combining pressure relief and drainage technology. This makes the structure formed after grouting more stable, the tunnel correction force more concentrated, and multiple components can monitor and record data of the grouting process and tunnel deformation in real time, ensuring the safety and stability of grouting. Attached Figure Description

[0029] Figure 1 A schematic diagram of a total station monitoring tunnel deformation;

[0030] Figure 2 This is a schematic diagram of grouting during unilateral deformation of the shield tunnel segment in the first embodiment;

[0031] Figure 3 This is a schematic diagram of grouting during bilateral deformation of the shield tunnel segments in the second embodiment;

[0032] Figure 4 This is a schematic diagram of the grouting device.

[0033] Figure 5 This is a schematic diagram of the inside of the directional valve;

[0034] Figure 6 This is a diagram showing the location distribution of grouting holes and pressure relief holes;

[0035] Figure 7 This is a diagram showing the layout of monitoring points for tunnel lining segments. Detailed Implementation

[0036] To facilitate understanding of the present invention, a more complete description will be given below with reference to various embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] Example 1 (Tunnel unilateral convergence deformation)

[0039] Please see Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 7 The first embodiment of the present invention provides a method for deformation grouting reinforcement and correction of shield tunnels in water-rich sand layers, comprising the following steps S1 to S6:

[0040] S1. By monitoring multiple points with a total station, the baseline and major and minor axis lengths of the shield tunnel after deformation are recorded to obtain the segment deformation convergence, determine the deformation status and location of the shield tunnel, and judge whether it is a single-sided or double-sided transverse convergence deformation of the tunnel.

[0041] In this embodiment, based on field test data, the ratio of the convergence value ΔD of tunnel segment 14 to the tunnel diameter D exceeds 12‰, indicating that the tunnel convergence deformation has reached a level requiring repair. Further comparison of the deformation degree of the tunnel's major and minor axes is then made. Figure 1 As shown, Figure 1In the diagram, A, B1, B2, C1, C2, D1, and D2 are convergence deformation monitoring points; E is a total station; and b, b′, c, c′, and d, d′ are the distances of the convergence deformation monitoring points from the baseline.

[0042] Based on the ratio of b to b′, it is determined whether the deformation is lateral convergence on one side or both sides of the tunnel. In this embodiment, if the ratio of b to b′ is greater than 50%, it is determined to be lateral convergence deformation on one side of the tunnel. Then, the ratios of b / b′, c / c′, and d / d′ are compared to determine the deformation location and mark it.

[0043] Among them, B1, B2, C1, C2, D1, and D2 are symmetrically distributed. The symmetry angle of B1 and B2 is 90°, C1 and C2 are on the same horizontal line as the track bed, and the symmetry angle of D1 and D2 is 135°.

[0044] S2, for the lateral convergence deformation on one side of the tunnel, two additional grouting holes are drilled on the shield segment using a drilling device on the deformed side.

[0045] Two additional grouting holes are drilled on the tunnel segment using a drilling device, symmetrical about the secondary grouting hole at 30°, with a depth of about 3m. A grouting area with a depth of 1m is drilled at one end of the symmetrical tunnel segment through the secondary grouting hole. During the drilling process, attention should be paid to surveying the distribution of the steel reinforcement in the tunnel segment.

[0046] After drilling, install the sleeve valve pipe and install the one-way valve on the upper part of the sleeve valve pipe. Extend the sleeve valve pipe 191 into the bottom of the borehole through the additional grouting hole. At the same time, extend the sleeve valve pipe 181 into the grouting area through the secondary grouting hole 18 on the other side of the pipe segment.

[0047] For tunnel unilateral lateral convergence deformation, the segment side needs to be reinforced on the other side of the deformation using a two-component grouting method. Specifically, for the two-component reinforcement grouting body 4, the directional valve inlet and outlet are manually adjusted, and cement-water glass two-component grouting is performed using sleeve valve pipe 181. At the same time, the adjacent pressure relief hole 20 is opened for pressure relief and drainage to expand the grouting range. Grouting can be stopped after 5 minutes when grout begins to appear in the adjacent pressure relief hole 20. The grouting pressure is set to 0.4-0.5 MPa during the grouting process.

[0048] The cement-water glass dual-liquid grout is described. The cement grout is primarily composed of 42.5 grade silicate cement with a water-cement ratio of 0.5:1-0.8:1; the water glass modulus is 2.8-3.1, and the concentration is 40-45 Be'. The cement grout to water glass grout ratio ranges from 1:0.5 to 1:0.3. The initial setting time of the grout is controlled within 2 minutes, and the final setting time within 18 minutes. The grouting method is as follows: the storage tanks of the two grouting lines are respectively filled with cement grout and water glass grout. The grouting pressure of the two grouting lines is maintained at 0.5-0.6 MPa, with the pressure variation range between 0.4-0.8 MPa. The reversing valve is adjusted to ensure that the two grouts are evenly mixed before being discharged.

[0049] S3, single-liquid high and low pressure pulse grouting, the grouting device adopts high and low pressure pulse grouting to perform synchronous grouting from top to bottom to the auxiliary grouting hole. During single-section grouting, if the flow meters of the two lines gradually slow down to stop or the grouting pressure reaches the final pressure, the grouting pipe is lowered and the above grouting process is repeated until the last section of grouting.

[0050] Specifically, for the high- and low-pressure pulse grouting body 1, the two grouting branches are activated separately for high-pressure grouting and low-pressure grouting, respectively, and converged at the reversing valve. The reversing valve is adjusted to alternate between high- and low-pressure pulse grouting. The total grouting length is 60cm. Grouting is carried out segment by segment from top to bottom through grouting pipe 191. When the grouting pressure of a single segment reaches the final pressure, the grouting pipe is lowered and the grouting process is repeated until the last segment. During the grouting process, the high pressure is set to 2-3MPa and the low pressure is set to 0.4-0.5MPa. The high- and low-pressure pumps are alternately started at a grouting frequency of 30 times / min. Grouting is carried out segment by segment from top to bottom. The segment length of each grouting segment is 10cm and the interval time is set to 5min. The final pressure is determined by the average grouting pressure of the pressure pump and the pressure gauge of the grouting branch, which is set to 0.1-0.2MPa.

[0051] The cement-based grout used for grouting is 42.5 grade ordinary Portland cement and XPM nano-grouting agent, with a water-cement ratio of 0.5:1-0.8:1; the amount of XPM agent added is 8%-10% of the mass of the mixture, and the initial setting time is controlled at 8-10 min and the final setting time is 30-35 min.

[0052] S4, dual-liquid grouting: After positioning the position of the first grouting stage, the second grouting stage is carried out by connecting the sleeve valve pipe through the secondary grouting hole of the segment. The grouting method adopts normal pressure and grouting from top to bottom in stages. When the grouting pressure of a single stage gradually increases to the final pressure, the grouting is stopped. The grouting pipe is lowered down and the above grouting process is repeated until the last stage of grouting is completed.

[0053] In step S4, the two-component grouting uses cement-water glass grout. The cement grout is mainly composed of 42.5 grade Portland cement with a water-cement ratio of 0.5:1-0.8:1. The water glass modulus is 2.8-3.1, and the concentration is 40-45Be'. The ratio of cement grout to water glass grout is 1:0.5-1:0.3. The initial setting time of the grout is controlled within 2 minutes, and the final setting time is controlled within 18 minutes.

[0054] The grouting method of dual-liquid grouting is as follows: the storage tanks of the two grouting lines are filled with cement grout and water glass grout respectively. The two grouting lines maintain the grouting pressure at 0.5-0.6MPa, keep the pressure variation range between 0.4-0.8MPa, and adjust the reversing valve to ensure that the two grouts are mixed evenly before grouting.

[0055] Specifically, for the dual-liquid grouting body 2, a secondary grouting hole 18 is drilled to a depth of 2m. The sleeve valve pipe 181 contacts the first grouting layer, and cement-water glass grout is used for grouting. The dual-liquid grouting is carried out sequentially from top to bottom under normal pressure, with a grouting length of 1m. The length of each grouting segment is set to 25cm, and the interval time is set to 60s. When the grouting pressure of a single segment reaches the final pressure, the grouting pipe is lowered until the last segment of grouting is completed. During the grouting process, the grouting pressure is set at 0.5-0.6MPa, and the pressure variation range is maintained between 0.4-0.8MPa.

[0056] S5, Dual-liquid secondary grouting: After step S4, continue lowering the grouting pipe segment by segment until it approaches the tunnel segment. The grouting pressure is set at 0.7-0.8 MPa, and the pressure variation range is maintained between 0.5-0.9 MPa. After adjusting the reversing valve to mix the two grouts, the grout is discharged. The single grouting distance is 40 cm and the interval is 45 s. At the same time, the secondary grouting holes adjacent to the tunnel segment are opened for pressure relief and drainage. Several monitoring points are arranged on the monitoring section of the grouting tunnel segment. If the tunnel displacement deformation rebound reaches 2 mm / h during the grouting process, the grouting is stopped and the monitoring frequency is increased until it stabilizes.

[0057] Specifically, for the double-liquid secondary grouting body 3, based on S4, double-liquid grouting is carried out segment by segment from top to bottom until the outside of the segment. The grouting spacing is 40cm and the interval is set to 45s. The grouting pressure is increased to 0.7-0.8MPa, and the pressure variation range is maintained between 0.5-0.9MPa. At the same time, the adjacent pressure relief hole 20 is opened to relieve pressure and drain water to expand the grouting range, and according to... Figure 7The tunnel lining segment monitoring system uses precision dial gauges (21) to monitor the grouting process in real time. Changes in the dial gauges are observed, and grouting is stopped and the monitoring frequency is increased when the grouting pressure reaches the final pressure or the tunnel's vertical displacement rebounds to 2 mm / h. A total of 7 monitoring points (with a monitoring accuracy of 0.01 mm) are set up, symmetrically in the vertical direction: 2 at the grouting location of the segment, 4 at the left and right trackbeds, and 1 at the top of the segment.

[0058] S6. After dismantling the grouting pipeline, clean up the site and continue to reinforce and correct the next deformed position.

[0059] In this embodiment, the grouting device has two grouting branches converging into a main grouting line. Each branch line is equipped with a storage tank 7, a pressure pump 8, a flow meter 10, and a pressure gauge 11. The pressure pump 8 is equipped with a pressure control gauge 9, which can adjust the high and low pressure to set different pressure grouting lines. The flow meter 10 and the pressure gauge 11 record real-time information of the grouting line.

[0060] The main grouting line is equipped with a reversing valve 12 and a control valve 13. The reversing valve 12 includes a valve body 15, a sealing assembly 16, and a handle 17. The reversing valve has multiple inlet and outlet ports P1, P2, P3, and P4 in the middle. The position of the handle 17 can be adjusted to allow multiple grouting branches to perform independent grouting and combined grouting. The control valve 13 controls the grouting switch of the entire device.

[0061] Example 2 (Tunnel bilateral convergence deformation)

[0062] Please see Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 The second embodiment of the present invention provides a method for deformation grouting reinforcement and correction of shield tunnels in water-rich sand layers, comprising the following steps S1 to S6:

[0063] S1. By monitoring multiple points with a total station, the baseline and major and minor axis lengths of the shield tunnel after deformation are recorded to obtain the segment deformation convergence, determine the deformation status and location of the shield tunnel, and judge whether it is a single-sided or double-sided transverse convergence deformation of the tunnel.

[0064] In this embodiment, based on field test data, the ratio of the convergence value ΔD of tunnel segment 14 to the tunnel diameter D exceeds 12‰, indicating that the tunnel convergence deformation has reached a level requiring repair. Further comparison of the deformation degree of the tunnel's major and minor axes is then made. Figure 1 As shown, Figure 1In the diagram, A, B1, B2, C1, C2, D1, and D2 are convergence deformation monitoring points; E is a total station; and b, b′, c, c′, and d, d′ are the distances of the convergence deformation monitoring points from the baseline.

[0065] Based on the ratio of b to b′, it is determined whether the deformation is lateral convergence on one side or both sides of the tunnel. In this embodiment, the ratio of b to b′ is less than 50%, indicating lateral convergence deformation on both sides of the tunnel. Then, the ratios of b / b′, c / c′, and d / d′ are compared to determine and mark the deformation location.

[0066] Among them, B1, B2, C1, C2, D1, and D2 are symmetrically distributed. The symmetry angle of B1 and B2 is 90°, C1 and C2 are on the same horizontal line as the track bed, and the symmetry angle of D1 and D2 is 135°.

[0067] S2, for the transverse convergence deformation on both sides of the tunnel, two additional grouting holes are drilled on the shield segment using a drilling device on the deformed side.

[0068] Specifically, for the double-sided deformation area, additional grouting holes 19 are symmetrically drilled on the segments along the tunnel centerline using a drilling device. The additional grouting holes on the same side are symmetrical at 30° and the depth is set to about 3m. During the drilling process, attention should be paid to surveying the distribution of the reinforcing steel in the segments.

[0069] After drilling, install the sleeve valve pipe and install the one-way valve on the upper part of the sleeve valve pipe. Simultaneously extend the sleeve valve pipe into the bottom of the borehole through the additional grouting holes on both sides of the pipe segment.

[0070] S3, single-liquid high and low pressure pulse grouting, the grouting device adopts high and low pressure pulse grouting to perform synchronous grouting from top to bottom to the auxiliary grouting hole. During single-section grouting, if the flow meters of the two lines gradually slow down to stop or the grouting pressure reaches the final pressure, the grouting pipe is lowered and the above grouting process is repeated until the last section of grouting.

[0071] Specifically, for the high- and low-pressure pulse grouting body 1′, the two grouting branches are activated separately for high-pressure grouting and low-pressure grouting, respectively, and converged at the reversing valve. The reversing valve is adjusted to alternate between high- and low-pressure pulse grouting. The total grouting length is 60cm. Grouting is carried out segment by segment from top to bottom through grouting pipe 191 and the other side grouting pipe 191. When the grouting pressure value of a single segment reaches the final pressure, the grouting pipe is lowered and the grouting process is repeated until the last segment. During the grouting process, the high pressure is set to 2-3MPa and the low pressure is set to 0.4-0.5MPa. The high- and low-pressure pumps are alternately started at a grouting frequency of 30 times / min. Grouting is carried out segment by segment from top to bottom. The segment length of each grouting segment is 10cm and the interval time is set to 5min. The final pressure is determined by the average grouting pressure of the pressure pump and the pressure gauge of the grouting branch, which is set to 0.1-0.2MPa.

[0072] The cement-based grout is prepared by using 42.5 grade ordinary Portland cement + XPM nano-injection agent, with a water-cement ratio of 0.5:1-0.8:1; the amount of XPM agent added is 8%-10% of the mass of the mixture, and the initial setting time is controlled at 8-10 min, and the final setting time is controlled at 30-35 min.

[0073] S4, dual-liquid grouting: After positioning the position of the first grouting stage, the second grouting stage is carried out by connecting the sleeve valve pipe through the secondary grouting hole of the segment. The grouting method adopts normal pressure and grouting from top to bottom in stages. When the grouting pressure of a single stage gradually increases to the final pressure, the grouting is stopped. The grouting pipe is lowered down and the above grouting process is repeated until the last stage of grouting is completed.

[0074] Specifically, for the dual-liquid grouting body 2′, a 2m deep borehole is drilled through the secondary grouting hole 18 of the segment. The sleeve valve pipe 181 contacts the first grouting layer, and cement-water glass grout is used for grouting. The dual-liquid grouting is carried out sequentially from top to bottom under normal pressure, with a grouting length of 1m. The length of each grouting segment is set to 25cm, and the interval time is set to 1min. When the grouting pressure of a single segment reaches the final pressure, the grouting pipe is lowered until the last segment of grouting is completed. During the grouting process, the grouting pressure is set at 0.5-0.6MPa, and the pressure variation range is maintained between 0.4-0.8MPa.

[0075] The cement-water glass slurry is prepared as follows: the cement slurry is mainly composed of 42.5 grade silicate cement with a water-cement ratio of 0.5:1-0.8:1; the water glass modulus is 2.8-3.1, the concentration is 40-45Be', and the ratio of cement slurry to water glass slurry is 1:0.5-1:0.3. The initial setting time of the slurry is controlled within 2 minutes, and the final setting time is controlled within 18 minutes.

[0076] S5, Dual-liquid secondary grouting: After step S4, continue lowering the grouting pipe segment by segment until it approaches the tunnel segment. The grouting pressure is set at 0.7-0.8 MPa, and the pressure variation range is maintained between 0.5-0.9 MPa. After adjusting the reversing valve to mix the two grouts, the grout is discharged. The single grouting distance is 40 cm and the interval is 45 s. At the same time, the secondary grouting holes adjacent to the tunnel segment are opened for pressure relief and drainage. Several monitoring points are arranged on the monitoring section of the grouting tunnel segment. If the tunnel displacement deformation rebound reaches 2 mm / h during the grouting process, the grouting is stopped and the monitoring frequency is increased until it stabilizes.

[0077] Specifically, for the two-component secondary grouting body 3′, based on S4, two-component segmented grouting is performed from top to bottom, with a total grouting length of 80cm, a segmented grouting spacing of 40cm, and an interval of 45s. The grouting pressure is increased to 0.7-0.8MPa, maintaining a pressure variation range between 0.5-0.9MPa. Simultaneously, the adjacent pressure relief hole 20 is opened to relieve pressure and drain water, expanding the grouting range. Figure 7 A precision dial gauge 21 is used to monitor the grouting process in real time during the tunnel lining segment monitoring. Changes in the dial gauge 21 are observed, and grouting is stopped and the monitoring frequency is increased when the grouting pressure reaches the final pressure or the tunnel's vertical displacement rebound reaches 2 mm / h. A total of 7 monitoring points are set up, symmetrically in the vertical direction: 2 at the grouting location of the segment, 4 at the left and right trackbeds, and 1 at the top of the segment.

[0078] S6. After dismantling the grouting pipeline, clean up the site and continue to reinforce and correct the next deformed position.

[0079] In summary, the grouting reinforcement and correction method for deformation of shield tunnels in water-rich sand layers provided by this invention has the following beneficial effects:

[0080] (1) The present invention uses a reversing valve to inject grout into the additional grouting hole with high and low pressure pulses, which can greatly expand the crack width of the sand layer, increase the channel for grout flow, enhance the penetration of grout, and increase the actual expansion area of ​​grout. In addition, the first grout uses a cement-based and XPM additive mixed grout with high strength, which can strengthen the strength of the surrounding soil and form a certain strength foundation for subsequent grouting.

[0081] (2) The present invention performs the second grouting through the secondary grouting hole of the pipe segment. The cement-water glass double liquid grout has a short setting time. Based on the first grouting solidification, the double liquid grout can quickly fill the gap of the first grout and together form an arc-shaped grout stop wall and a grouting ring reaction wall.

[0082] (3) The present invention utilizes the arc reaction wall formed by the first and second grouting solids through the final high-pressure grouting to concentrate the lateral thrust to correct the deformation of the shield tunnel.

[0083] (4) This invention solves the problem of uneven grout diffusion during grouting by using multiple grouting processes in a step-by-step manner and combining pressure relief and drainage technology. This makes the structure formed after grouting more stable, the tunnel correction force more concentrated, and multiple components can monitor and record data of the grouting process and tunnel deformation in real time, ensuring the safety and stability of grouting.

[0084] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for deformation grouting reinforcement and correction of shield tunnels in water-rich sand layers, characterized in that, Includes the following steps: S1. By monitoring multiple points with a total station, the baseline and major and minor axis lengths of the shield tunnel after deformation are recorded to obtain the segment deformation convergence, determine the shield tunnel deformation and location, and judge whether it is a single-sided lateral convergence deformation or a double-sided lateral convergence deformation of the tunnel. S2. If the tunnel undergoes lateral convergence deformation on one side, two additional grouting holes are drilled on the shield segment using a drilling device on the deformed side. If the tunnel undergoes lateral convergence deformation on both sides, two additional grouting holes are drilled symmetrically on both sides of the tunnel. S3, single-liquid high and low pressure pulse grouting, the grouting device adopts high and low pressure pulse grouting to perform synchronous grouting from top to bottom to the auxiliary grouting hole. During single-section grouting, if the flow meters of the two lines gradually slow down to stop or the grouting pressure reaches the final pressure, the grouting pipe is lowered and the above grouting process is repeated until the last section of grouting. S4, dual-liquid grouting: After positioning the position of the first grouting, the second grouting is carried out by connecting the sleeve valve pipe through the secondary grouting hole of the segment. The grouting method adopts normal pressure grouting from top to bottom in stages. When the single-stage grouting pressure is gradually increased to the final pressure, the grouting is stopped. The grouting pipe is lowered down and the above grouting process is repeated until the last grouting is completed. S5, Double-liquid secondary grouting: After step S4, continue to lower the grouting pipe and grout section by section until it is close to the tunnel segment. The grouting pressure is set at 0.7-0.8MPa, and the pressure variation range is maintained between 0.5-0.9MPa. After adjusting the reversing valve to mix the two grouts, the grout is discharged. The single grouting distance is 40cm and the interval is 45s. At the same time, the secondary grouting holes adjacent to the tunnel segment are opened for pressure relief and drainage. Several monitoring points are arranged on the monitoring section of the grouting tunnel segment. If the tunnel displacement deformation rebound reaches 2mm / h during the grouting process, the grouting is stopped and the monitoring frequency is increased until it stabilizes. S6. After disassembling the grouting pipeline, clean up the site and continue to reinforce and correct the next deformed position. In step S3, the cement-based grout used for grouting is 42.5 grade ordinary Portland cement and XPM nano-grouting agent, with a water-cement ratio of 0.5:1-0.8:1; the amount of XPM agent added is 8%-10% of the mass of the mixture, and the initial setting time is controlled at 8-10 min and the final setting time is 30-35 min. The total grouting length is 60cm. The grouting pressure range of the high-pressure pump is set to 2-3MPa, and the grouting pressure range of the low-pressure pump is set to 0.4-0.5MPa. The grouting frequency of alternating high-pressure and low-pressure pumps is 30 times / min. Grouting is carried out segment by segment from top to bottom. The segment length of each grouting segment is 10cm and the interval time is set to 5min. The final pressure is determined based on the average grouting pressure of the pressure pump's built-in pressure control gauge and the grouting branch pressure gauge, and is set to 0.1-0.2 MPa; In step S4, the two-component grouting uses cement-water glass grout. The cement grout is mainly composed of 42.5 grade Portland cement with a water-cement ratio of 0.5:1-0.8:

1. The water glass modulus is 2.8-3.1, and the concentration is 40-45Be'. The ratio of cement grout to water glass grout is 1:0.5-1:0.

3. The initial setting time of the grout is controlled within 2 minutes, and the final setting time is controlled within 18 minutes. The grouting method of dual-liquid grouting is as follows: the storage tanks of the two grouting lines are filled with cement grout and water glass grout respectively. The two grouting lines maintain the grouting pressure at 0.5-0.6MPa, keep the pressure variation range between 0.4-0.8MPa, and adjust the reversing valve to ensure that the two grouts are mixed evenly before grouting.

2. The method for deformation grouting reinforcement and correction of shield tunnels in water-rich sandy layers according to claim 1, characterized in that, Step S1 specifically includes: By monitoring multiple points with a total station to record the baseline and major and minor axis lengths of the shield tunnel after deformation, if the ratio of the tunnel segment convergence value ΔD to the tunnel diameter D exceeds 12‰, it is determined that the tunnel convergence deformation has reached the level that needs to be repaired. Further comparison of the degree of tunnel major and minor axis deformation is made, and it is determined whether the tunnel is undergoing unilateral or bilateral lateral convergence based on the degree of tunnel major and minor axis deformation.

3. The method for deformation grouting reinforcement and correction of shield tunnels in water-rich sandy layers according to claim 1, characterized in that, In step S2, for tunnel unilateral lateral convergence deformation or tunnel bilateral lateral convergence deformation, the two additional grouting holes are symmetrical about the secondary grouting holes of the segments at 30°, the drilling depth is set to 3m, the sleeve valve pipe is installed after drilling, and the one-way valve is installed on the upper part of the sleeve valve pipe.

4. The method for deformation grouting reinforcement and correction of shield tunnels in water-rich sandy layers according to claim 1, characterized in that, For tunnel unilateral lateral convergence deformation, the segment side needs to be reinforced on the other side of the unilateral deformation using the double-liquid grouting method in step S4, and then grouting should be performed on the unidirectional deformation according to steps S3-S5. For the transverse convergence deformation on both sides of the tunnel, grouting is carried out on both sides of the deformation according to steps S3-S5.

5. The method for deformation grouting reinforcement and correction of shield tunnels in water-rich sandy layers according to claim 1, characterized in that, In the grouting device used for grouting, two grouting branches converge into the main grouting line. Each branch is equipped with a storage tank, a pressure pump, a flow meter, and a pressure gauge. The pressure pump is equipped with a pressure control gauge, which can be adjusted to set different pressure grouting lines. The flow meter and pressure gauge record real-time information of the grouting line.

6. The method for deformation grouting reinforcement and correction of shield tunnels in water-rich sandy layers according to claim 5, characterized in that, The main grouting line is equipped with a reversing valve and a control valve. The reversing valve includes a valve body, a sealing component, and a handle. The reversing valve has multiple inlet and outlet ports in the middle. The handle position can be adjusted to allow multiple grouting branches to perform independent grouting or joint grouting. The control valve controls the grouting switch of the entire grouting device.

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