Real-time monitoring system for filling state of tunnel secondary lining concrete

Abstract

The invention relates to a tunnel secondary lining concrete filling state real-time monitoring system which is characterized in that a secondary lining cavity is defined by a secondary lining template in a tunnel, the system comprises a sensor array located in the secondary lining cavity, the sensor array comprises a plurality of rows of optoelectronic switches distributed in the extending direction of the tunnel, and the optoelectronic switches in the same row are distributed in the circumferential direction of the tunnel; the signal processing and acquisition unit is responsible for supplying power to the photoelectric switch and converting the received signal of the photoelectric switch into a signal displayed by a display; and the data processing and displaying unit is responsible for displaying the signals transmitted by the signal processing and collecting unit on a reality device. The invention aims to provide the tunnel secondary lining concrete filling state real-time monitoring system capable of acquiring the cavity in real time, and the problem that the existing cavity can only be acquired afterwards is solved.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering construction and quality monitoring technology, and in particular to a real-time monitoring system for the filling status of secondary lining concrete in tunnels. Background Technology

[0002] In tunnels constructed using the shield tunneling method, secondary lining concrete pouring is required after the segment installation. Because the tunnel is circular and the pouring inlet is typically located on the lower side, when the concrete flows to the tunnel roof, it is prone to forming unfilled voids (commonly known as "incomplete compaction" or "inadequate filling") due to factors such as incomplete air expulsion and increased flow resistance. These voids significantly reduce the integrity, load-bearing capacity, and durability of the lining, posing a serious threat to the long-term operational safety of the tunnel.

[0003] Currently, the quality inspection of secondary lining pouring relies heavily on non-destructive testing methods such as post-construction ground-penetrating radar scanning. However, this method is a post-construction inspection and cannot provide real-time feedback during the pouring process. Once voids are discovered, complex post-construction remedial grouting is required, which is not only costly and of uncertain effectiveness but also severely restricts construction efficiency. Traditional grouting management methods rely on injection pressure and leakage from adjacent grouting holes to determine whether filling is complete. This method is extremely inaccurate and cannot ensure that voids are completely filled.

[0004] Therefore, there is an urgent need in this field for a technical solution that can monitor the filling status of secondary lining concrete in real time, accurately and at low cost, especially the filling status of the top area. Summary of the Invention

[0005] The present invention aims to provide a real-time monitoring system for the filling status of secondary lining concrete in tunnels that can detect cavities in real time, thus solving the problem that existing systems can only detect cavities after the fact.

[0006] The above technical problems are solved by the following technical solution: a real-time monitoring system for the filling status of secondary lining concrete in tunnels. The system comprises a secondary lining cavity enclosed by a secondary lining template within the tunnel. The system includes a sensor array located within the secondary lining cavity. The sensor array includes several rows of photoelectric switches distributed along the tunnel's extension direction, with each row of photoelectric switches distributed circumferentially along the tunnel. A signal processing and acquisition unit is responsible for powering the photoelectric switches and converting the received signals into signals for display. A data processing and display unit is responsible for displaying the signals transmitted from the signal processing and acquisition unit on the display. During concrete pouring, when the concrete submerges the photoelectric switches, the display shows that the area is filled with concrete. When a void occurs in the filled area, the display shows that a void exists. Voids are eliminated by increasing the grouting pressure or changing the grouting hole. This technical solution can detect voids in real-time, allowing for timely elimination. Eliminating voids is convenient; if voids are detected only after the concrete has hardened, eliminating them becomes cumbersome.

[0007] Preferably, the spacing between photoelectric switches in the fan-shaped areas at 60° to the left and right of the tunnel arch centerline is 0.5 to 1 meter; the spacing between photoelectric switches in areas outside the fan-shaped areas at 60° to the left and right of the tunnel arch centerline is 1.5 to 2 meters. The area within the 60° arc is the endpoint of concrete flow, most affected by gravity, and most prone to voids due to pumping pressure loss and air accumulation. It is the absolute core of quality control; therefore, the sensor spacing in this area should be significantly increased. Outside the 60° arc, the concrete has better fluidity and is relatively easy to fill, but its filling process still needs to be monitored to understand the overall flow pattern. Therefore, the sensor spacing in this area can be appropriately relaxed. This differentiated arrangement scheme effectively controls the total number of sensors while ensuring monitoring accuracy in key areas, achieving the best balance between cost and benefit.

[0008] Preferably, the photoelectric switch is a reflective photoelectric switch, comprising a switch body and a reflector. The connection end of the switch body is provided with a power line and a signal line. The working end of the switch body is used to emit and receive light signals. The power lines of the same row of photoelectric switches are connected in parallel to the power supply line. The power supply line and signal line are fixed on a first flexible strip. The reflector is fixed on a second flexible strip, and both the second and second flexible strips extend circumferentially along the tunnel. The photoelectric switch is prefabricated on the flexible strip, thus facilitating its fixing within the secondary lining cavity.

[0009] Preferably, the secondary lining cavity is provided with several steel arch frames distributed along the tunnel extension direction. The steel arch frames extend circumferentially along the tunnel and include an inner steel plate, an outer steel plate, and a connecting steel plate connecting the inner and outer steel plates. The inner steel plate, outer steel plate, and connecting steel plate are connected in an "I" shape. The plane of the connecting steel plate is perpendicular to the tunnel extension direction. Both the first and second flexible strips are flat strips. The first flexible strip is fixed flat to the inner circumferential surface of the outer steel plate, and the second flexible strip is fixed flat to the outer circumferential surface of the inner steel plate. This allows for easy flat fixing of the flexible strips, ensuring reliable operation of the photoelectric switch.

[0010] Preferably, the flexible strip is fixed from the tunnel arch towards both ends. When the switch body and reflector are misaligned due to the radius difference between the inner and outer steel plates, the second flexible strip is partially folded to align the switch body and reflector. This method facilitates the alignment of the switch body and reflector.

[0011] Preferably, the power cord and signal core are encased within a first flexible strip, the terminals of the switch body are embedded within the first flexible strip, the working end of the switch body is exposed on the surface of the first flexible strip, and one end of the reflector is embedded within a second flexible strip, while the other end is exposed on the surface of the second flexible strip. This design prevents the switch body and reflector from shaking, improving the anti-interference capability of the photoelectric switch.

[0012] Preferably, a comparison rod is also included. One end of the comparison rod has a connecting hole, and the working end of the switch body protrudes from the surface of the flexible strip. The connecting hole is used to fit onto the working end of the switch body. During the installation of the photoelectric switch, the connecting hole of the comparison rod is fitted onto the switch body, and the alignment of the other end of the comparison rod with the reflector is observed to determine whether the switch body is aligned with the reflector. This improves the convenience of adjusting the position of the switch body and the reflector when debugging the photoelectric switch.

[0013] Preferably, the comparison rod includes a first section with the connecting hole at one end and a second section sleeved on the other end of the first section. During use, the length of the comparison rod is adjusted by the distance between the inner and outer steel plates, ensuring that the comparison rod remains close to the reflector, avoiding judgment errors caused by a large distance. The distance between the two steel plates of the steel arch frame varies in different tunnels. It has good versatility.

[0014] Preferably, the secondary lining template has a conical hole with a larger inner end and a smaller outer end at the location corresponding to the photoelectric switch. A conical plug that seals the conical hole is inserted inside the conical hole, and a drive handle is connected to the outer end of the conical plug. When the fixed switch detects a gap, the conical plug is pushed or pulled by gripping the corresponding drive handle, allowing the air in the cavity to be discharged through the conical hole. This improves the reliability of air discharge and cavity elimination. Existing methods of eliminating cavities by increasing grouting pressure do not actually eliminate cavities by truly venting air; instead, the increased pressure compresses the cavity size and causes the air in the cavity to diffuse into the concrete, forming smaller, harder-to-detect cavities. The presence of these cavities still affects the quality of the secondary lining. Moreover, the increased pressure makes fixing the secondary lining more difficult and may damage the tunnel floor. This technical solution solves this problem.

[0015] Preferably, the diameter of the portion where the drive handle connects to the conical plug is equal to the diameter of the small-diameter section of the conical plug, and the conical plug and the conical surface of the conical hole cooperate to form a seal. This ensures reliable sealing, allowing the drive handle to easily enter the conical hole when the plug is pulled out.

[0016] The present invention has the following advantages: (1) Controllable filling process: The present invention moves the quality control node from after pouring to during pouring, realizing real-time monitoring and active control of the filling state of the tunnel top. It enables construction personnel to discover and correct defects as soon as they occur, improving the reliability of the project quality.

[0017] (2) Data-driven assisted judgment: Judgment is based on the sudden change of light intensity, an objective physical quantity, which eliminates the randomness and uncertainty of human experience, making the judgment results accurate and reliable. The monitoring data provides an important reference for the standardization and digitization of quality management.

[0018] (3) Improve overall construction efficiency: This system not only ensures quality, but also avoids excessive pumping of concrete by accurately judging the pouring endpoint, thus directly saving material costs. It optimizes the construction process, reduces the time spent waiting for testing and subsequent processing, and speeds up the turnover of the trolley, thereby improving the overall construction efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of Embodiment 1 of the present invention; Figure 2 This is a partial schematic diagram of Example 2; Figure 3 for Figure 2 A magnified view of a portion of point A.

[0020] In the diagram: 1. Secondary lining template; 2. Signal processing and acquisition unit; 3. Data processing and display unit; 4. Switch body; 5. Reflector; 6. Power cord; 7. Signal line; 8. Power supply line; 9. First flexible strip; 10. Second flexible strip; 11. Steel arch frame; 12. Inner steel plate; 13. Outer steel plate; 14. Connecting steel plate; 15. Comparison rod; 16. Connecting hole; 17. First section; 18. Second section; 19. Conical plug; 20. Drive handle; 21. Part connecting the drive handle and the conical plug; 22. Photoelectric switch; 23. Secondary lining cavity; 24. Folding protrusion; 25. Tunnel. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1, see Figure 1 A real-time monitoring system for the filling status of secondary lining concrete in a tunnel is disclosed. The tunnel 25 is enclosed by a secondary lining template 1 to form a secondary lining cavity 23. The invention includes a sensor array located within the secondary lining cavity. The sensor array comprises several rows of photoelectric switches distributed along the tunnel's extension direction, with each row of photoelectric switches 22 distributed circumferentially along the tunnel. A signal processing and acquisition unit 2 is responsible for powering the photoelectric switches and converting the received signals into signals for display. A data processing and display unit 3 is responsible for displaying the signals transmitted from the signal processing and acquisition unit on the display. During concrete pouring, if the concrete submerges the photoelectric switches, the display will show that the area is filled. If a void occurs in the filled area, the display will show that a void exists, allowing the void to be eliminated by increasing the grouting pressure or changing the grouting holes. The spacing between the photoelectric switches in the fan-shaped area 60° to the left and right of the tunnel cross-section's arch centerline is 0.5 to 1 meter; the spacing between the photoelectric switches in areas outside the fan-shaped area 60° to the left and right of the tunnel cross-section's arch centerline is 1.5 to 2 meters. The photoelectric switches are reflective photoelectric switches. The photoelectric switch includes a switch body 4 and a reflector 5.

[0023] See Figure 2 The main body of the switch has a power line 6 and a signal line 7 at its connection end, and the working end of the switch is used to transmit and receive optical signals. Example 2 differs from Example 1 in the following aspects: See Figure 2 and Figure 3The power lines of the photoelectric switches in the same row are connected in parallel on the power supply line 8. The power supply line and signal line are fixed on the first flexible strip 9, and the reflector is fixed on the second flexible strip 10. Both the first and second flexible strips extend along the circumference of the tunnel. The secondary lining cavity is provided with several steel arch frames 11 distributed along the tunnel extension direction. The steel arch frames extend along the tunnel circumference and include an inner steel plate 12, an outer steel plate 13, and a connecting steel plate 14 that connects the inner and outer steel plates together. The inner steel plate, the outer steel plate, and the connecting steel plate are connected together in an "I" shape. The plane where the connecting steel plate is located is perpendicular to the tunnel extension direction. Both the first and second flexible strips are flat strips. The first flexible strip is fixed to the inner circumference of the outer steel plate in a flat manner, and the second flexible strip is fixed to the outer circumference of the inner steel plate in a flat manner. When fixing the flexible strip, it is fixed from the tunnel arch towards both ends. When the switch body and reflector are misaligned due to the radius difference between the inner and outer steel plates, the second flexible strip is partially folded to form a folded protrusion 24 to align the switch body with the reflector. The power cord and signal core are wrapped inside the first flexible strip, the wiring terminals of the switch body are buried inside the first flexible strip, and the working end of the switch body protrudes from the surface of the first flexible strip. One end of the reflector is buried inside the second flexible strip, and the other end is exposed on the surface of the second flexible strip. It also includes a comparison rod 15, with a connecting hole 16 on one end face. The connecting hole is used to fit onto the working end of the switch body. During the installation of the photoelectric switch, the connecting hole of the comparison rod is fitted onto the switch body, and the alignment of the other end of the comparison rod with the reflector is observed to determine whether the switch body and the reflector are aligned. After installation, the comparison rod is removed. The comparison rod includes a first section 17 with a connecting hole at one end and a second section 18 fitted onto the other end of the first section. The secondary lining template has a conical hole with a larger inner end and a smaller outer end at the location corresponding to the photoelectric switch. A conical plug 19, which seals the conical hole, is inserted inside the conical hole. A drive handle 20 is connected to the outer end of the conical plug. When the fixed switch detects a gap, the air in the cavity is discharged through the conical hole by pushing or pulling the corresponding drive handle. The diameter of the part 21 where the drive handle connects to the conical plug is equal to the diameter of the small diameter section of the conical plug. The conical plug and the conical hole's conical surface fit together to form a seal.

Claims

1. A real-time monitoring system for the concrete filling status of tunnel secondary lining, wherein a secondary lining cavity is formed within the tunnel using secondary lining templates, characterized in that... It includes a sensor array located within the secondary lining cavity, the sensor array comprising several rows of photoelectric switches distributed along the tunnel extension direction, with the same row of photoelectric switches distributed circumferentially along the tunnel; a signal processing and acquisition unit responsible for powering the photoelectric switches and converting the received signals from the photoelectric switches into signals for display; and a data processing and display unit responsible for displaying the signals transmitted from the signal processing and acquisition unit on the display device.

2. The real-time monitoring system for the filling status of secondary tunnel lining concrete according to claim 1, characterized in that, The spacing between photoelectric switches in the fan-shaped area 60° to the left and right of the center line of the tunnel arch is 0.5 meters to 1 meter; the spacing between photoelectric switches in the area outside the fan-shaped area 60° to the left and right of the center line of the tunnel arch is 1.5 meters to 2 meters.

3. A real-time monitoring system for the filling status of secondary tunnel lining concrete according to claim 1 or 2, characterized in that, The photoelectric switch is a reflective photoelectric switch, which includes a switch body and a reflector. The connection end of the switch body is provided with a power line and a signal line. The working end of the switch body is used to emit and receive light signals. The power lines of the same row of photoelectric switches are connected in parallel on the power supply line. The power supply line and the signal line are fixed on the first flexible strip. The reflector is fixed on the second flexible strip. Both the first and second flexible strips extend along the circumference of the tunnel.

4. The real-time monitoring system for the filling status of secondary tunnel lining concrete according to claim 3, characterized in that, The secondary lining cavity is provided with several steel arch frames distributed along the tunnel extension direction. The steel arch frames extend circumferentially along the tunnel. Each steel arch frame includes an inner steel plate, an outer steel plate, and a connecting steel plate that connects the inner and outer steel plates together. The inner steel plate, the outer steel plate, and the connecting steel plate are connected together in an "I" shape. The plane where the connecting steel plate is located is perpendicular to the tunnel extension direction. The first flexible strip and the second flexible strip are both flat strips. The first flexible strip is fixed to the inner circumferential surface of the outer steel plate in a flat manner, and the second flexible strip is fixed to the outer circumference of the inner steel plate in a flat manner.

5. The real-time monitoring system for the filling status of secondary tunnel lining concrete according to claim 4, characterized in that, When fixing the flexible strip, it is fixed from the tunnel arch towards both ends. When the switch body and the reflector are misaligned due to the radius difference between the inner and outer steel plates, the second flexible strip is partially folded to align the switch body and the reflector.

6. The real-time monitoring system for the filling status of secondary tunnel lining concrete according to claim 3, characterized in that, The power cord and signal core are wrapped in the first flexible strip. The wiring terminals of the switch body are buried in the first flexible strip. The working end of the switch body is exposed on the surface of the first flexible strip. One end of the reflector is buried in the second flexible strip, and the other end is exposed on the surface of the second flexible strip.

7. A real-time monitoring system for the filling status of secondary tunnel lining concrete according to claim 6, characterized in that, It also includes a comparison rod, one end of which has a connecting hole. The working end of the switch body protrudes from the surface of the flexible strip, and the connecting hole is used to fit onto the working end of the switch body.

8. A real-time monitoring system for the filling status of secondary tunnel lining concrete according to claim 7, characterized in that, The comparison rod includes a first section with the connecting hole at one end and a second section sleeved on the other end of the first section.

9. A real-time monitoring system for the filling status of secondary tunnel lining concrete according to claim 1 or 2, characterized in that, The secondary lining template has a conical hole with a larger inner end and a smaller outer end at the location corresponding to the photoelectric switch. A conical plug that closes the conical hole is inserted inside the conical hole, and a drive handle is connected to the outer end of the conical plug.

10. A real-time monitoring system for the filling status of secondary tunnel lining concrete according to claim 9, characterized in that, The diameter of the part where the drive handle connects to the conical plug is equal to the diameter of the small diameter section of the conical plug, and the conical plug and the conical surface of the conical hole cooperate to seal.

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