Radial Split-Type Grouting Reinforcement and Combined Sealing Method for Shield Tunnels

Abstract

The present invention provides a radially separable grouting reinforcement and combined plugging method in a shield tunnel. After the shield tunnel segment ring is assembled, the self-propelled drill bit connected to the front end of the separable grouting pipe is used to drill into the required depth along the reserved grouting hole of the segment; the temporary plugging piece for grouting operation is inserted between the rear end split pipe and the reserved grouting hole of the segment; the cement slurry is injected from the tail of the rear end split pipe and flows into the stratum outside the tunnel structure through the slurry outlet hole on the wall of the front end grouting pipe; after the cement slurry grouting is completed, the cement slurry is adjusted to double liquid slurry for double liquid grouting; after the double liquid slurry solidifies, the front end grouting pipe is separated from the rear end split pipe; three plugging measures are sequentially performed in the reserved grouting hole of the segment. The present invention has a simple structure, simple process operation, strong feasibility, good reinforcement quality and good plugging effect.

Description

Technical Field

[0001] The invention belongs to the technical field of shield tunnel construction, and in particular relates to a radially separable grouting reinforcement and combined plugging method in a shield tunnel. Background Art

[0002] With the rapid development of urban infrastructure, my country's cross-river and cross-sea shield tunnels are also facing the problem of diverse and complex strata. For underwater deep-buried shield tunnels, if there are unfavorable strata such as thick silt and liquefied sand layers around them, more and more tunnels are beginning to adopt the radial grouting reinforcement scheme inside the tunnel. This scheme can effectively avoid the interference and impact of surface operations on the surrounding environment, and it is highly targeted and has good reinforcement effects.

[0003] During the construction of conventional radial grouting in shield tunnels, the general operation sequence is to drill holes first, replace the backward grouting equipment when the drilling depth reaches the design requirements, complete the grouting reinforcement operation, and finally seal the reserved holes. In the above operations in relevant existing engineering cases, there are common problems such as sand seepage and water leakage during the adjustment and connection between drilling and grouting equipment, excessive grouting pressure during backward grouting causing segment misalignment, and slow solidification of slurry after grouting causing slurry overflow. Not only is the reinforcement effect difficult to guarantee, but it is also easy to cause secondary hazards, thus affecting the normal traffic of the tunnel and the safety of the tunnel structure. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a radially separable grouting reinforcement and combined sealing method in a shield tunnel, which has a simple structure, simple process operation, strong feasibility, good reinforcement quality and good sealing effect.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] The present invention provides a radially separable grouting reinforcement and combined plugging method in a shield tunnel, the method comprising the following steps:

[0007] Step S1, reserving reserved grouting holes on the shield segment structure to meet the requirements of radial grouting construction of the shield tunnel; after the shield tunnel segment ring is assembled, drilling into the required design depth along the reserved grouting holes of the segment through a self-propelled drill bit connected to the front end of the separable grouting pipe;

[0008] The separable grouting pipe comprises a front grouting pipe and a rear split pipe, wherein the front grouting pipe and the rear split pipe are detachably connected; a self-feeding drill bit is connected to the front end of the front grouting pipe; and a plurality of grouting holes are arranged on the wall of the front grouting pipe;

[0009] Step S2, inserting a temporary plugging piece for grouting operation between the rear end split pipe and the reserved grouting hole of the pipe segment to play a role of fixing and temporarily plugging, ensuring that the grout will not leak into the tunnel during grouting;

[0010] Step S3, injecting cement slurry from the tail of the rear end split pipe, and flowing into the stratum outside the tunnel structure through the slurry outlet holes on the wall of the front end grouting pipe, and then dynamically adjusting the grouting pressure to ensure that the cement slurry produces splitting and penetration effects in the gaps of the stratum and diffuses to the reinforcement range required by the design;

[0011] Step S4, after the cement slurry grouting is completed, the cement slurry is adjusted to double-liquid slurry, and double-liquid grouting is performed to achieve rapid coagulation;

[0012] Step S5, after the double-liquid slurry solidifies, the front grouting pipe is separated from the rear split pipe to avoid disturbance to the completed reinforcement body;

[0013] Step S6, performing three sealing measures in sequence in the reserved grouting holes of the pipe segments to complete the radial grouting reinforcement combined sealing work in the shield tunnel.

[0014] Preferably, in step S6, the three sealing measures performed in sequence are: firstly setting a water-swellable waterstop strip in the reserved grouting hole of the segment, then injecting an inert slurry, and finally inserting a slurry stop plug.

[0015] Preferably, the outer diameter of the front end grouting pipe matches the inner diameter of the rear end split pipe; the rear outer wall of the front end grouting pipe is provided with a threaded section, and the front inner wall of the rear end split pipe is provided with an internal threaded section matching the threaded section, and the front end grouting pipe and the rear end split pipe are threadedly connected via the threaded section and the internal threaded section.

[0016] Preferably, the drill bit of the self-feeding drill bit is pointed or twisted.

[0017] Preferably, the shape and size of the slurry outlet holes on the wall of the front grouting pipe are set according to the grouting pressure and the grouting amount to ensure that the slurry is injected into the formation from the slurry outlet holes; the slurry outlet holes are evenly distributed on the wall of the front grouting pipe, and the shape of the slurry outlet holes can be circular or elongated.

[0018] Preferably, the size of the water-swellable waterstop strip is matched according to the water pressure outside the tunnel and the size of the reserved grouting holes in the pipe segment.

[0019] Preferably, the water content of the inert slurry is matched according to the size of the water-swellable waterstop strip.

[0020] Preferably, the double liquid slurry in step S4 is cement-water glass double liquid slurry.

[0021] The present invention has the following beneficial effects:

[0022] The radially separable grouting reinforcement and combined plugging method provided by the present invention has a simple structure, simple process operation, strong feasibility, good reinforcement quality and good plugging effect. It avoids the phenomenon of sand seepage and water leakage when the drilling and grouting equipment are adjusted and connected, the excessive grouting pressure during the backward grouting process causes the pipe segment to be misaligned, and the grouting liquid overflows due to the slow solidification of the grouting liquid after the grouting is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the embodiments of the present invention.

[0024] Figure 1 Schematic diagram of a radially separable grouting reinforcement method in a shield tunnel according to an embodiment of the present invention;

[0025] Figure 2 for Figure 1 Schematic diagram of section 1-1;

[0026] Figure 3 It is a schematic diagram of a radially separable grouting reinforcement combined plugging method in a shield tunnel according to an embodiment of the present invention;

[0027] Figure 4 Schematic diagram of the rear end split pipe of the split grouting pipe in an embodiment of the present invention.

[0028] Description of reference numerals:

[0029] 1. Self-propelled drill bit; 2. Slurry outlet hole; 3. Front grouting pipe; 4. Threaded section; 5. Shield segment; 6. Water-swellable waterstop strip; 7. Inert slurry; 8. Slurry stop plug; 9. Rear split pipe; 91. Internal threaded section; 10. Temporary plugging piece for grouting operation; 11. Grouting hole reserved for the segment. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Example

[0032] The railway cross-river and cross-sea tunnel project is constructed using the shield method. The tunnel has an outer diameter of 12.8m, an inner diameter of 11.7m, a segment thickness of 550mm, a ring width of 2.0m, and a maximum water depth of 80m. Due to the presence of liquefiable sand layers in the strata, and considering that the structure of the tunnel may produce the most unfavorable sand liquefaction phenomenon when the stratum intensity is VII during the operation stage, it will affect the normal traffic of the tunnel and the safety of the tunnel structure.

[0033] Therefore, this embodiment provides a radially separable grouting reinforcement and combined plugging method in a shield tunnel. Figures 1 to 4 , the method comprises the following steps:

[0034] Step S1, reserve two φ50mm reserved grouting holes 11 on each shield segment 5; after the shield tunnel segment ring is assembled, drill into the reserved grouting holes 11 of 3.0m through the self-propelled drill bit 1 connected to the front end of the separable grouting pipe.

[0035] The separable grouting pipe comprises a front grouting pipe 3 and a rear split pipe 9, which are detachably connected to each other; a self-propelled drill bit 1 is connected to the front end of the front grouting pipe 3; and a plurality of grouting holes 2 are arranged on the wall of the front grouting pipe 3.

[0036] Step S2, insert the temporary sealing piece 10 for grouting operation between the rear end split pipe 9 and the reserved grouting hole 11 of the pipe segment, which plays the role of fixing and temporary sealing, and ensures that the slurry will not leak into the tunnel during grouting; the temporary sealing piece 10 for grouting operation needs to be matched according to the size of the reserved grouting hole 11 of the pipe segment and the rear end split pipe 9 to ensure that it can be stuck in the gap between the two.

[0037] Step S3, inject cement slurry with a water-cement ratio of 1:1 from the tail of the rear end split pipe 9, and flow into the stratum outside the tunnel structure through the slurry outlet hole 2 on the wall of the front end grouting pipe 3. The maximum grouting pressure is controlled at 1.0 MPa, and the grouting diffusion radius is 1.5 m.

[0038] Step S4, after the cement slurry grouting is completed, the cement slurry is adjusted to cement-water glass double liquid slurry, and double liquid grouting is performed to achieve rapid coagulation and serve as a temporary plugging.

[0039] Step S5, after the cement-water glass double slurry solidifies, the front grouting pipe 3 is separated from the rear split pipe 9 to avoid disturbance to the completed reinforcement body.

[0040] Step S6, perform three sealing measures in sequence in the reserved grouting holes 11 of the segment, that is, first perform the first sealing measure in the reserved grouting holes 11 of the segment - setting a water-swellable waterstop strip 6 (the first sealing measure is not limited to a water-swellable waterstop strip, and other rubber materials with good durability with expansion and elastic compression effects can also be selected), then perform the second sealing measure - inject inert slurry 7, and finally perform the third sealing measure - insert the slurry stop plug 8 to complete the radial grouting reinforcement combined sealing work in the shield tunnel.

[0041] Furthermore, the outer diameter of the front end grouting pipe 3 matches the inner diameter of the rear end split pipe 9; the rear outer wall of the front end grouting pipe 3 is provided with a threaded section 4, and the front inner wall of the rear end split pipe 9 is provided with an internal threaded section 91 matching the threaded section 4; the front end grouting pipe 3 and the rear end split pipe 9 are threadedly connected via the threaded section 4 and the internal threaded section 91.

[0042] Furthermore, the drill bit of the self-feeding drill bit 1 can be selected into a pointed shape, a twisted shape, etc. according to needs. In the present embodiment, the drill bit is in a pointed shape.

[0043] Furthermore, the shape and size of the slurry outlet holes 2 on the wall of the front grouting pipe 3 are set according to the grouting pressure and the grouting amount to ensure that the slurry is injected into the formation from the slurry outlet holes 2; the slurry outlet holes 2 are evenly distributed on the wall of the front grouting pipe 3, and the shape of the slurry outlet holes 2 can be circular or elongated. In the present embodiment, the shape of the slurry outlet holes 2 is circular.

[0044] Furthermore, the size of the water-swellable waterstop strip 6 is matched according to the water pressure outside the tunnel and the size of the reserved grouting holes 11 of the pipe segment.

[0045] Furthermore, after the inert slurry 7 is injected, it acts locally on the water-swellable waterstop strip 6, causing the water-swellable waterstop strip 6 to undergo an early active micro-expansion effect, thereby stimulating the initial stage of blocking effect. Therefore, the water content of the inert slurry 7 is matched according to the size of the water-swellable waterstop strip 6.

[0046] It can be seen from the above technical scheme that the radially separable grouting reinforcement and combined plugging method provided in the shield tunnel provided by this embodiment has a simple structure, simple process operation, strong feasibility, good reinforcement quality, and good plugging effect. It avoids the phenomenon of sand seepage and water leakage when the drilling and grouting equipment are adjusted and connected, the excessive grouting pressure during the backward grouting process causes the pipe segment to be misaligned, and the grouting overflows due to the slow solidification of the grouting after the grouting is completed.

[0047] The above embodiments of the present invention are described in detail through examples, but the contents described are only exemplary embodiments of the embodiments of the present invention and cannot be considered to limit the scope of implementation of the embodiments of the present invention. The protection scope of the embodiments of the present invention is defined by the claims. Anyone who utilizes the technical solutions described in the embodiments of the present invention, or who, inspired by the technical solutions of the embodiments of the present invention, designs similar technical solutions within the essence and protection scope of the embodiments of the present invention to achieve the above technical effects, or who makes equal changes and improvements to the scope of application, shall still fall within the scope of protection covered by the patent of the embodiments of the present invention.

Claims

1. A radially separable grouting reinforcement and combined plugging method in a shield tunnel, characterized in that: The method comprises the following steps: Step S1, reserving a reserved grouting hole (11) on the shield segment structure (5) to meet the radial grouting construction of the shield tunnel; after the shield tunnel segment ring is assembled, drilling into the required design depth along the reserved grouting hole (11) through a self-propelled drill bit (1) connected to the front end of the separable grouting pipe; The separable grouting pipe comprises a front grouting pipe (3) and a rear split pipe (9), wherein the front grouting pipe and the rear split pipe are detachably connected; a self-propelled drill bit (1) is connected to the front end of the front grouting pipe (3); and a plurality of grouting holes (2) are arranged on the wall of the front grouting pipe (3); Step S2, inserting the temporary plugging piece (10) for grouting operation between the rear end split pipe (9) and the reserved grouting hole (11) of the pipe segment, plays a role of fixing and temporarily plugging, and ensures that the grout will not leak into the tunnel during grouting; Step S3, injecting cement slurry from the tail of the rear end split pipe (9), flowing into the stratum outside the tunnel structure through the slurry outlet hole (2) on the pipe wall of the front end grouting pipe (3), and then dynamically adjusting the grouting pressure to ensure that the cement slurry produces a splitting and penetration effect in the gaps between the strata and diffuses to the reinforcement range required by the design; Step S4, after the cement slurry grouting is completed, the cement slurry is adjusted to double-liquid slurry, and double-liquid grouting is performed to achieve rapid coagulation; Step S5, after the double-liquid slurry solidifies, the front grouting pipe (3) and the rear split pipe (9) are separated to avoid disturbance to the completed reinforcement body; Step S6, performing three blocking measures in sequence in the reserved grouting holes (11) of the pipe segments to complete the radial grouting reinforcement combined blocking work in the shield tunnel; In step S6, the three blocking measures are performed in sequence: firstly, a water-swellable water stop strip (6) is set in the reserved grouting hole (11) of the pipe segment, then an inert slurry (7) is injected, and finally, a slurry stop plug (8) is inserted; The outer diameter of the front grouting pipe (3) matches the inner diameter of the rear split pipe (9); the rear outer wall of the front grouting pipe (3) is provided with a threaded section (4), and the front inner wall of the rear split pipe (9) is provided with an internal threaded section (91) matching the threaded section (4); the front grouting pipe (3) and the rear split pipe (9) are threadedly connected via the threaded section (4) and the internal threaded section (91); The double liquid slurry in step S4 is cement-water glass double liquid slurry.

2. The radially separable grouting reinforcement and combined plugging method in a shield tunnel according to claim 1 is characterized in that: The drill bit shape of the self-feeding drill bit (1) is a pointed shape or a twisted shape.

3. The radially separable grouting reinforcement and combined plugging method in a shield tunnel according to claim 1 is characterized in that: The shape and size of the slurry outlet holes (2) on the wall of the front grouting pipe (3) are set according to the grouting pressure and the grouting amount to ensure that the slurry is injected into the formation from the slurry outlet holes (2); the slurry outlet holes (2) are evenly distributed on the wall of the front grouting pipe (3), and the shape of the slurry outlet holes (2) can be circular or elongated.

4. The radially separable grouting reinforcement and combined plugging method in a shield tunnel according to claim 1, characterized in that: The size of the water-swellable water stop strip (6) is matched according to the water pressure outside the tunnel and the size of the reserved grouting hole (11) of the pipe segment.

5. The radially separable grouting reinforcement and combined plugging method in a shield tunnel according to claim 1 is characterized in that: The water content of the inert slurry (7) is matched according to the size of the water-swellable waterstop strip (6).

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