Tunnel vacuum-assisted void disease treatment method

Abstract

The invention discloses a tunnel vacuum-assisted void disease treatment method. The method comprises the following steps that firstly, holes are drilled in a second lining of a tunnel and located in a void area range; secondly, a grouting pipe is coaxially installed in the drill hole; the outer end of the grouting pipe is connected with a tee joint; a first valve, a third valve and a second valve are respectively mounted on a first branch pipe, a second branch pipe and a third branch pipe of the tee joint; thirdly, a grouting pipeline is connected with a third valve, the first valve is closed, and a second valve and the third valve are opened; fourthly, grouting is conducted on the grouting pipeline, and grouting flows out from a third branch and a second valve; closing the third valve; 5, connecting the second valve with a vacuum pipeline, and opening the first valve; 6, the void area is sucked to be in a vacuum state; 7, closing the second valve and the vacuum equipment; the third valve is opened, and the slurry flows into the void area. According to the method, air, water and impurities in a void area are discharged under the action of vacuum negative pressure, slurry diffusion air resistance is broken, and void gaps are densely filled.

Description

Technical Field

[0001] This invention belongs to the field of tunnel defect treatment technology, specifically relating to a method for treating tunnel vacuum-assisted de-cavitation defects. Background Technology

[0002] With the continuous expansion of tunnel construction scale and the extension of operating life, the problem of tunnel structural voids has become increasingly prominent, becoming a key hidden danger affecting tunnel operational safety and structural durability. Tunnel voids are mainly concentrated behind the lining, at the interface between the surrounding rock and the lining, and inside the lining. They are mostly caused by factors such as incomplete grouting during construction, insufficient compaction of the lining during pouring and vibration, settlement and deformation of the surrounding rock during operation, erosion by groundwater, and temperature stress. They occur frequently in both highway and railway tunnels.

[0003] The presence of voids behind and inside the lining can severely degrade the stress state of the tunnel structure. The voids reduce the effective load-bearing area of ​​the lining, leading to significant local stress concentration. Under long-term operation, this can easily cause secondary problems such as lining cracking, spalling, and water leakage, and in severe cases, it can lead to structural instability and failure. At the same time, the voids can easily accumulate groundwater and corrosive media, accelerating the corrosion of the lining steel bars and the carbonization of the concrete, significantly reducing the service life of the tunnel structure. This not only increases the cost of later maintenance but also poses a serious threat to the safety of passing vehicles and personnel, hindering the safe and efficient operation of transportation infrastructure.

[0004] Currently, the main treatment technologies for tunnel voiding in the industry include traditional pressure grouting, borehole grouting, and lining replacement. However, existing treatment technologies face numerous technical bottlenecks in practical applications, making it difficult to achieve efficient and thorough treatment of voids: First, traditional pressure grouting relies on the gravity of the grout itself and pump pressure to fill the voided area, but air easily remains inside the void, forming air resistance, leading to insufficient grout diffusion and incomplete filling, resulting in a "false filling" phenomenon and a high recurrence rate of voids after treatment; Second, borehole grouting requires opening multiple grouting holes in the lining, causing additional damage to the lining structure, and the grouting range and volume are difficult to control precisely, easily leading to excessive grout overflow and waste or localized insufficient filling; Third, for voids inside the lining and micro-crack type, existing technologies lack effective media drainage and grout guidance methods, making it difficult for the grout to penetrate into small voids, resulting in poor treatment targeting; Fourth, extensive drilling operations damage the original secondary lining structure, causing secondary defects, and the construction process is cumbersome and time-consuming, significantly impacting the normal operation of the tunnel. Summary of the Invention

[0005] The purpose of this invention is to provide a vacuum-assisted method for treating tunnel voids, which can efficiently remove air, groundwater and impurities from the voided area through vacuum negative pressure, break the air resistance of grout diffusion, and guide the grout to accurately and densely fill the voids.

[0006] This invention adopts the following technical solution: A method for treating tunnel vacuum-assisted voiding defects, comprising the following steps: Step 1: Drill holes in the secondary lining of the tunnel, within the void area, until the holes reach the void area, but do not penetrate the waterproof layer attached to the primary support. Step 2: Install the grouting pipe coaxially inside the borehole from Step 1. One end of the grouting pipe extends into the void space, while the other end protrudes from the borehole. Connect the first branch pipe of the tee to the outer end of the grouting pipe. The other two branch pipes of the tee are the second and third branch pipes, respectively. Install valve No. 1, valve No. 3, and valve No. 2 on the first branch pipe, the second branch pipe, and the third branch pipe, respectively; Step 3: Connect the grouting pipeline to valve No. 3, close valve No. 1, and open valves No. 2 and No. 3; Step 4: Inject grout into the grouting pipeline. The grout flows in through the grouting pipeline and flows out through the third branch and valve No. 2; close valve No. 3 (14). Step 5: Connect valve 2 to the vacuum line and open valve 1; Step 6: Start the vacuum equipment to evacuate the gas in the degaussing area and bring the degaussing area into a vacuum state. Step 7: Close valve 2 and shut down the vacuum equipment; open valve 3, and the grout will flow into the degaussing area through the grouting pipeline.

[0007] Furthermore, in step five, a waste collection box is connected between the vacuum equipment and the vacuum pipeline to collect groundwater and impurities extracted from the vacuum area by the vacuum equipment.

[0008] Furthermore, in step four, after closing valve number three, the grouting pressure is reduced to maintain a stable pressure in the grouting pipeline.

[0009] Furthermore, in step one, a hole is drilled near the center within the vacancy area.

[0010] The beneficial effects of this invention are: 1. By drilling a hole in the secondary lining of the tunnel within the void area and installing a T-junction inside the hole, with the two branch pipes outside the T-junction being a grouting pipeline and a vacuum pipeline respectively, air, groundwater, and impurities in the void area can be efficiently discharged through vacuum negative pressure, breaking the air resistance of grout diffusion and guiding the grout to accurately and densely fill the void gaps. 2. Opening a hole in the secondary lining of the tunnel can reduce damage to the original lining structure, achieve precise control of the grouting process, and improve the thoroughness and durability of the defect treatment. 3. Using a T-junction to connect grouting and vacuuming eliminates the need to disassemble instruments during the process, simplifying the construction process. Attached Figure Description

[0011] Figure 1A schematic diagram of a vacuum-assisted method for treating tunnel delamination defects; Figure 2 A schematic diagram illustrating the control method for treating tunnel vacuum-assisted de-cavitation defects. The components are: 1. Initial support; 2. Waterproof layer; 3. Void area; 4. Secondary lining; 5. Grouting pipe; 6. T-junction; 7. Grouting pipeline; 8. Grouting machine; 9. Vacuum pipeline; 10. Waste collection bin; 11. Vacuum equipment; 12. Valve No. 1; 13. Valve No. 2; 14. Valve No. 3. Detailed Implementation

[0012] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0013] This invention discloses a method for treating tunnel vacuum-assisted voiding defects, used to treat voiding between the secondary lining 2 and the primary support 1 of a tunnel. The method includes the following steps: Step 1: Use radar scanning to determine the tunnel void area; drill a hole on the secondary lining 2 of the tunnel, near the center of the void area, until the hole reaches the void area, but does not penetrate the waterproof layer 2 attached to the primary support 1; Figure 1 and 2 As shown.

[0014] Step 2: Install the grouting pipe 5 coaxially inside the borehole from Step 1. One end of the grouting pipe extends into the void space, and the other end protrudes from the borehole. Connect the first branch pipe of the tee 6 to the outer end of the grouting pipe 5. The other two branch pipes of the tee 6 are the second branch pipe and the third branch pipe, respectively. Install valve 12, valve 14, and valve 13 on the first branch pipe, the second branch pipe, and the third branch pipe, respectively; Step 3: Connect the grouting pipeline 7 to valve 14, close valve 12, and open valves 13 and 14. Step 4: Turn on the grouting machine 8 and inject grout into the grouting pipe 7. The grout flows into the grouting pipe 7 and flows out through the third branch and valve 13 to remove all the air from the grouting pipe 7. Close valve 14 and reduce the grouting pressure to keep the grouting pipe 7 under stable pressure. Step 5: Connect valve 13 to one end of vacuum pipeline 9, and connect the other end of vacuum pipeline 9 to waste collection box 10. Waste collection box 10 is also connected to vacuum equipment 11. Open valve 13. Waste collection box 10 is used to collect groundwater and impurities in the vacated area space extracted by vacuum equipment (11).

[0015] Step 6: Start the vacuum equipment 11. The vacuum equipment 11 draws gas from the degaussing area through the vacuum pipeline 9 to make the degaussing area reach a vacuum state. Step 7: Close valve 13 and vacuum equipment 11; open valve 14 to increase the grouting pressure to the design pressure. The grout flows into the voided area through the grouting pipeline 7 and is stabilized for 2 minutes.

[0016] After grouting in the voided area is completed, close valve 12 and shut down grouting machine 8; remove grouting machine 8, vacuum equipment 11, and waste collection box 10. After the grout in the voided area has fully set, remove tee 6 and cut off the exposed grouting pipe 5 of the secondary lining to the secondary lining plane.

[0017] In this invention, air, groundwater and impurities in the voided area are efficiently discharged through vacuum negative pressure, breaking the air resistance of grout diffusion and guiding the grout to accurately and densely fill the voided space; at the same time, it can reduce damage to the original lining structure, achieve precise control of the grouting process, and improve the thoroughness and durability of disease treatment.

Claims

1. A method for treating a tunnel of a vacuum- assisted void disease, characterized by, The method comprises the following steps: Step one, drilling a hole on the second lining (2) within the range of the void area, the depth of the hole is until the void area, but not penetrating the waterproof layer (2) attached to the primary support (1); Step two, installing a grouting pipe (5) coaxially in the hole in step one, one end of the grouting pipe extends into the void space, and the other end is exposed outside the hole; connecting a first branch pipe of a tee joint (6) to the outer end of the grouting pipe (5), the other two branch pipes of the tee joint 6 are a second branch pipe and a third branch pipe respectively; A first valve (12), a third valve (14) and a second valve (13) are respectively installed on the first branch pipe, the second branch pipe and the third branch pipe; Step three, connecting the grouting pipe (7) with the third valve (14), closing the first valve (12), and opening the second valve (13) and the third valve (14); Step four, grouting the grouting pipe (7), the slurry flows into the grouting pipe (7) and flows out through the third branch pipe and the second valve (13); closing the third valve (14); Step five, connecting the second valve (13) with the vacuum pipe (9) and opening the first valve (13); Step six, starting the vacuum equipment (11) to suck the gas in the void area, so that the void area reaches a vacuum state; Step seven, closing the second valve (13) and the vacuum equipment (11), and opening the third valve (14), the slurry flows into the void area from the grouting pipe (7).

2. The tunnel vacuum-assisted disbond treatment method of claim 1, wherein, In step five, a dirt recovery tank (10) is connected between the vacuum equipment (11) and the vacuum pipe (9) to receive the underground water and impurities in the void area space sucked by the vacuum equipment (11).

3. The tunnel vacuum-assisted disbond treatment method of claim 2, wherein, In step four, after closing the third valve (14), the grouting pressure is lowered to keep the grouting pipe (7) in a stable pressure state.

4. The tunnel vacuum-assisted disbond treatment method of claim 3, wherein, In step one, the hole is drilled near the center within the range of the void area.

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