A method for sealing grouting holes in tunnel lining segments

Abstract

A method for sealing grouting holes in tunnel lining segments includes the following steps: After grouting is completed in the segment drilling, the grouting hole is enlarged and threads are formed using a threaded drill bit slightly larger than the grouting hole; an eccentric drill is used to cut a recessed notch inside the grouting hole; a pre-reserved grouting needle is installed on the threaded edge of the grouting hole; the grouting hole is filled with sealing material, and threaded reinforcing bars are implanted into the grouting hole; after filling, modified epoxy resin reinforcing grout is injected through the pre-reserved grouting needle; after grouting, the pipe is closed and allowed to solidify before acceptance. This method is simple to operate, can effectively seal the grouting holes after segment grouting, prevent water seepage from the pores, and improve the structural strength of the sealed holes.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel construction technology, and in particular to a method for sealing grouting holes in tunnel segments. Background Technology

[0002] Currently, shield tunnel construction is increasingly common in urban rail transit. Shield tunnels are structures assembled from precast reinforced concrete shield segments. According to general design, shield segments are pre-drilled for hoisting and grouting, facilitating later segment installation and secondary grouting. However, in cases where grouting reinforcement for tunnel connecting passages or pre-drilled secondary grouting is insufficient, it is often necessary to drill new holes in the segments for soil grouting reinforcement, such as full-section perforated pipe grouting reinforcement of the connecting passage strata or pre-grouted small guide pipe grouting.

[0003] After the grouting of the tunnel segments is completed, the mortar or cement slurry inside the grouting holes will shrink, forming a seepage channel and causing water leakage. When the gaps in the grouting holes of the shield tunnel segments are not filled tightly or form a channel connecting with rivers, lakes, or seas, high water pressure will cause water leakage in the grouting holes, and may even cause the cement rods inside the grouting holes to be pushed out by the high water pressure, resulting in mudslides and water inrush accidents, posing a great hidden danger to the safe operation of shield tunnels. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, the present invention provides a method for sealing grouting holes of tunnel segments. The method is simple to operate, can effectively seal the grouting holes after the tunnel segments are grouted, prevent water seepage from the pores, and improve the structural strength of the sealed holes.

[0005] To achieve the above objectives, the present invention employs the following technical solution: a method for sealing grouting holes in tunnel segments, comprising the following steps: after grouting is completed in the tunnel segments, a threaded drill bit slightly larger than the grouting hole is used to enlarge the grouting hole and form threads; an eccentric drill is used to cut a recessed incision inside the grouting hole; a pre-reserved grouting needle is installed on the threaded edge of the grouting hole; the grouting hole is filled and sealed with sealing material, and threaded steel bars are implanted in the grouting hole; after filling, modified epoxy resin reinforcing grout is injected through the pre-reserved grouting needle; after grouting is completed, the pipe is closed and allowed to solidify before acceptance.

[0006] As a further improvement of the present invention, during the drilling and grouting of the pipe segments, it is necessary to reinforce the soil and pre-embed grouting pipes. The steel pipes are driven into the soil, and the grouting pipes within the thickness range of the pipe segment wall are made of PVC material and connected to the steel pipes.

[0007] As a further improvement of the present invention, after the grouting of the segment drilling is completed, the solidified cement grout rods in the grouting hole are cleaned by a pre-drilling machine.

[0008] As a further improvement of the present invention, when using an eccentric drill for cutting, the number of cuts is increased according to the thickness of the pipe segment and the groundwater conditions.

[0009] As a further improvement of the present invention, before filling the sealing material, the grouting hole is cleaned and coated with epoxy resin.

[0010] As a further improvement of the present invention, the sealing material is micro-expansion cement mortar with a strength not lower than that of the segment concrete.

[0011] As a further improvement of the present invention, the threaded steel bar is a 12mm threaded steel bar.

[0012] As a further improvement of the present invention, when using a pre-reserved grouting needle to inject modified epoxy resin reinforcing grout, the grouting pressure is 0.3 to 0.5 MPa. Grouting of the grouting hole can be stopped when grout comes out of the adjacent grouting hole. After the pipe is closed and allowed to solidify for 8 to 12 hours, the pipe opening is checked. If the pipe opening is not full, a second or more grouting is performed.

[0013] As a further improvement of the present invention, after acceptance, the reserved grouting needles are removed, and then epoxy mortar is used to seal the area after the reserved grouting needles are removed; sandpaper is used to polish the contaminants on the inner arc surface of the pipe segment, and then concrete surface color difference repair agent is applied to restore the treated area to its original appearance.

[0014] The beneficial effects of this invention are as follows: This method is simple and convenient to operate. By enlarging the hole with a threaded drill bit and cutting with an eccentric drill to form threads and cuts, the contact surface and friction between the grouting hole and the sealing material can be increased, thereby improving the pull-out resistance of the sealing material after solidification. At the same time, the insertion of threaded steel bars can improve the structural strength, and the pores of the threaded edge can be filled by the reserved grouting needle, thereby effectively sealing the grouting hole, preventing water seepage from the pores, and improving the structural strength of the sealed hole. Attached Figure Description

[0015] Figure 1 This is a schematic cross-sectional view of the grouting hole sealing method described in this invention;

[0016] Marking instructions: 1-segment, 2-grouting hole, 3-thread, 4-cut, 5-sealing material, 6-threaded steel bar. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0018] A method for sealing grouting holes in tunnel lining segments, wherein the grouting hole sealing structure formed by the method is as follows: Figure 1 As shown, the method includes the following steps:

[0019] 1. When drilling and grouting segment 1, it is necessary to pre-embed grouting pipes for soil reinforcement after drilling segment 1. Steel pipes are driven into the soil. The grouting pipes within the wall thickness of segment 1 are made of PVC material and connected to the steel pipes driven into the soil. This is beneficial for the subsequent cleaning and sealing of grouting hole 2 of segment 1.

[0020] 2. After the drilling and grouting of segment 1 is completed, use a pre-drilling machine to clean the solidified cement grout rods in grouting hole 2;

[0021] 3. Use a threaded drill bit slightly larger than the grouting hole 2 to enlarge the grouting hole 2 and form a thread 3, thereby increasing the contact area between the grouting hole 2 and the sealing material 5;

[0022] 4. Use an eccentric drill to cut inside the grouting hole 2 to form a recessed incision 4. Increase the number of incisions 4 according to the thickness of the pipe segment 1 and the groundwater conditions.

[0023] 5. Install the reserved grouting needle on the thread 3 side of grouting hole 2;

[0024] 6. Before filling with sealing material 5, clean the grouting hole 2 and apply epoxy resin.

[0025] 7. Use sealing material 5 to fill and seal the grouting hole 2, and insert threaded steel bar 6 into the grouting hole 2. The sealing material 5 is micro-expansion cement mortar with a strength not lower than that of the concrete of segment 1. The threaded steel bar 6 is 12mm threaded steel bar 6. The threaded steel bar 6 is used to increase the strength of the filling sealing material 5.

[0026] 8. After the sealing material 5 fills the grouting hole 2, there are gaps along the direction of the thread 3. Modified epoxy resin reinforcing grout is injected into the gaps through the reserved grouting needle. Before grouting, the openings other than the reserved grouting needle are temporarily sealed. The grouting pressure is 0.3 to 0.5 MPa. Grouting of the grouting hole 2 is stopped when grout comes out of the adjacent grouting hole 2. After the pipe is closed and allowed to solidify for 8 to 12 hours, the inspection is carried out. If the pipe is not full, a second or more grouting is carried out to ensure the grouting quality and improve the overall compressive strength and impermeability grade.

[0027] 9. After the above procedures are completed and accepted, remove the reserved grouting needles, and then seal the area after the reserved grouting needles are removed with epoxy mortar; use sandpaper to polish the contaminants on the inner arc surface of the pipe segment 1, and then apply a concrete surface color difference repair agent to restore the treated area to its original appearance.

[0028] The above-described embodiments are merely illustrative of the present invention and are not intended to limit the present invention in any way. Any person skilled in the art who makes partial modifications or alterations to the technical content disclosed in the present invention without departing from the scope of the technical features of the present invention shall still fall within the scope of the technical features of the present invention.

Claims

1. A method for sealing grouting holes in tunnel lining segments, characterized in that... Includes the following steps: After the grouting of the tunnel segments is completed, the grouting holes are enlarged and threads are formed using a threaded drill bit slightly larger than the grouting hole; an eccentric drill is used to cut a recessed notch inside the grouting hole; a pre-reserved grouting needle is installed on the threaded edge of the grouting hole; the grouting hole is filled and sealed with sealing material, and threaded steel bars are implanted in the grouting hole; after filling, modified epoxy resin reinforcing grout is injected through the pre-reserved grouting needle, and the pipe is closed after grouting is completed and accepted after curing.

2. The method for sealing grouting holes in tunnel lining segments according to claim 1, characterized in that: During the grouting of the tunnel segments, soil reinforcement is required to pre-embed grouting pipes. Steel pipes are driven into the soil. Within the thickness of the tunnel segment wall, the grouting pipes are made of PVC material and connected to the steel pipes.

3. The method for sealing grouting holes in tunnel lining segments according to claim 1, characterized in that: After the grouting of the tunnel segments is completed, the solidified cement grout rods inside the grouting holes are cleaned using a pre-drilling machine.

4. The method for sealing grouting holes in tunnel lining segments according to claim 1, characterized in that: When using an eccentric drill for cutting, the number of cuts should be increased according to the thickness of the tunnel segments and the groundwater conditions.

5. The method for sealing grouting holes in tunnel lining segments according to claim 1, characterized in that: Before filling the sealing material, the grouting hole should be cleaned and coated with epoxy resin.

6. The method for sealing grouting holes in tunnel lining segments according to claim 1, characterized in that: The sealing material is micro-expansion cement mortar with a strength not lower than that of the segment concrete.

7. The method for sealing grouting holes in tunnel lining segments according to claim 1, characterized in that: The threaded steel bars used are 12mm threaded steel bars.

8. The method for sealing grouting holes in tunnel lining segments according to claim 1, characterized in that: When using pre-reserved grouting needles to inject modified epoxy resin reinforcing grout, the grouting pressure is 0.3 to 0.5 MPa. Grouting of the grouting hole can be stopped when grout comes out of the adjacent grouting hole. After the pipe is closed and allowed to solidify for 8 to 12 hours, check the pipe at the opening. If the pipe at the opening is not full, perform a second or more grouting.

9. The method for sealing grouting holes in tunnel lining segments according to claim 1, characterized in that: After acceptance, the reserved grouting needles are removed, and then epoxy mortar is used to seal the area after the reserved grouting needles are removed; sandpaper is used to polish the contaminants on the inner arc surface of the pipe segment, and then concrete surface color difference repair agent is applied to restore the treated area to its original appearance.

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