Plug-in combined type liquid collecting and distributing ring for freezing connection channel of super-large-diameter shield tunnel

Abstract

The invention provides a super-large-diameter shield tunnel freezing connection channel inserting combined type liquid collecting and distributing ring which comprises a top cover, one or more liquid collecting and distributing ring assembly sections and a support which are fixedly connected in sequence from top to bottom. Connecting flanges are fixedly arranged at the lower end of the top cover, the upper and lower ends of the liquid collecting and distributing ring assembly section and the upper end of the bracket and are fixedly combined and connected through bolts; and sealing rings are arranged between adjacent flanges. The assembly made of stainless steel is adopted, and a high-precision flange is matched with a sealing ring, a modular hydraulic locking structure or a standard prefabricated pipe joint rapid inserting system, so that the field welding link is thoroughly eliminated, the reliability and the sealing performance of liquid collecting and distributing ring connection are greatly improved, it is ensured that refrigerants are efficiently circulated without leakage, the working environment is remarkably improved, and the working efficiency is improved. Welding fume can be completely eradicated, ventilation pressure is reduced, construction safety is improved, rapid lossless disassembly and assembly and efficient turnover and reuse of the whole set of liquid collecting and distributing ring device are further achieved, and material consumption of a single project and engineering construction cost are greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of shield tunnels, in particular to a plug-in combined liquid distribution ring for freezing communication channels in super-large diameter shield tunnels. Background Art

[0002] With the sustained and rapid development of my country's national economy and the accelerating pace of urbanization, transportation demand in major cities is growing annually. Underground transportation is being developed on a large scale to alleviate road congestion and improve the urban environment. Underground tunnel construction is booming, and the number of ultra-large-diameter shield tunnel projects (Shield tunnels with a diameter of 14 meters or greater, which can accommodate traffic needs of two-deck four-lane or single-deck three-lane tunnels, are referred to as ultra-large-diameter shield tunnels) is increasing year by year. Connecting passages, constructed between ultra-large-diameter twin tunnels, serve purposes such as connectivity, drainage, emergency evacuation, and fire prevention, and are a crucial component of tunnel construction. Currently, the vast majority of connecting passages in my country are still excavated using the mining method. In ultra-large-diameter tunnel projects in water-rich strata, the intersection between the tunnel and connecting passage and the surrounding strata are disturbed by construction, resulting in complex stress conditions. Excavating connecting passages underground presents significant risks, and even the slightest carelessness can lead to construction accidents such as water and sand inrush.

[0003] To reduce the construction risks of ultra-large-diameter shield tunnels, the vast majority of connecting passageways in my country are constructed using a combination of freeze reinforcement and underground excavation. The freeze method is a crucial construction method for traversing complex strata and water-rich soft soil. It utilizes artificial refrigeration to freeze water in the soil, forming a solid, closed permafrost ring that resists water and soil pressure and isolates groundwater. Excavation and construction proceed under the protection of the frozen wall.

[0004] Before freezing operations begin, freezing pipes must be drilled into the ground. -28°C low-temperature brine circulates through the pipes, freezing the moisture inside the soil to form frozen ground. The brine in the freezing pipes needs to be distributed and collected using a distribution ring. Currently, existing distribution rings are welded on-site, which presents the following problems: (1) The welding quality of on-site welding pipelines is poor, and problems such as water leakage and seepage at the joints often occur; (2) On-site welding produces a lot of welding smoke, and the toxic gas is slowly dissipated in the confined space of the tunnel, which poses a great threat to the health of welders; (3) The welded liquid distribution ring is mostly made of low-carbon steel pipes. Salt water is highly corrosive to the liquid distribution ring, making it difficult to reuse and resulting in a certain amount of waste. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a plug-in combined liquid distribution ring for the freezing communication channel of an ultra-large diameter shield tunnel, including a top cover, one or more liquid distribution ring segments and a bracket fixedly connected in sequence from top to bottom. The lower end of the top cover, the upper and lower ends of the liquid distribution ring segment and the upper end of the bracket are all fixedly provided with connecting flanges and are fixedly connected by bolts, and a sealing ring is provided between adjacent flanges.

[0006] As a preferred solution, an outer sleeve connecting pipe is provided at the lower end of the top cover and the liquid collecting and distributing ring assembly, and an inner sleeve connecting pipe is provided at the upper end of the liquid collecting and distributing ring assembly and the bracket, and the outer sleeve connecting pipe and the inner sleeve connecting pipe are nested inside and outside.

[0007] As a preferred solution, an air release valve is provided at the upper end of the top cover to release the air accumulated during the freezing process.

[0008] As a preferred solution, the liquid collecting and distributing ring assembly includes a vertical connecting pipe and a plurality of horizontal hose connectors connected to the freezing pipes. The hose connectors are arranged on the side walls of the connecting pipe and can be connected in multiple directions.

[0009] As a preferred solution, the outer wall of the hose connector is provided with anti-falling threads.

[0010] As a preferred solution, the bracket includes a vertical main pipe connector and a plurality of supporting legs, and the supporting legs are fixedly arranged on the outside of the main pipe connector and the number of the supporting legs is not less than 3.

[0011] As a preferred solution, the top cover, the liquid collecting and distributing ring assembly and the bracket are made of stainless steel.

[0012] The beneficial effects of the present invention are: This invention proposes an efficient, safe, and green solution to address the problems of poor welding quality stability (prone to defects such as incomplete fusion and slag inclusions) caused by extensive on-site welding work in traditional liquid distribution rings during the construction of freezing communication channels in ultra-large diameter shield tunnels; severe welding fume pollution in the working environment (affecting the health of construction workers and posing a risk of explosion); and the difficulty of disassembling the liquid distribution ring and freezing pipes after welding, resulting in an inability to reuse them (resulting in high-cost materials and wasted resources). By utilizing stainless steel components and using high-precision flanges with sealing rings, a modular hydraulic locking structure, or a standard prefabricated pipe joint quick-connect system, on-site welding is completely eliminated. This not only significantly improves the reliability and sealing of the liquid distribution ring connection, ensuring efficient and leak-free refrigerant circulation, significantly improves the working environment, eliminates welding fume generation, reduces ventilation pressure, and enhances construction safety, but also enables rapid, non-destructive disassembly and efficient turnover and reuse of the entire liquid distribution ring assembly, significantly reducing material consumption and construction costs for individual projects. This device solves the bottleneck of traditional processes, comprehensively guarantees the uniformity, integrity and controllability of the formation of the freezing curtain, and provides core technical support for the safe, green, economical and high-quality construction of freezing communication channels in ultra-large diameter shield tunnels under complex geological conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings, wherein Figure 1 It is a structural schematic diagram of the present invention.

[0014] Figure 2 It is a structural schematic diagram of the top cover of the present invention.

[0015] Figure 3 It is a structural schematic diagram of the liquid distribution ring assembly section of the present invention.

[0016] Figure 4 Schematic diagram of the structure of the support of the present invention.

[0017] The numbers in the figure are: 1. Top cover; 2. Liquid distribution ring assembly; 21. Connecting pipe; 22. Hose connector; 23. Anti-drop thread; 3. Bracket; 31. Main pipe connector; 32. Support leg; 4. Connecting flange; 5. Outer sleeve connecting pipe; 6. Inner sleeve connecting pipe; 7. Air release valve. DETAILED DESCRIPTION

[0018] To illustrate the features of the present invention, the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Example: See also Figures 1 to 4An embodiment of the present invention provides a plug-in modular distribution ring specifically designed for freezing communication channels in ultra-large diameter shield tunnels. Its core lies in its modular stainless steel flange connection and nested sleeve structure, completely eliminating on-site welding. The device primarily comprises three functional modules: a top cover 1, three flexibly stackable distribution ring segments 2 (arranged longitudinally to accommodate varying freezing depths), and a load-bearing and positioning base support 3. These three main components are rigidly connected in series, axially from top to bottom.

[0020] To achieve efficient and highly reliable non-welded connections, connection flanges 4 with standardized dimensions and high-precision mating surfaces are pre-fabricated and fixed to the lower outer edge of the top cover 1, the upper and lower end faces of each liquid distribution ring segment 2, and the upper end face of the bracket 3. These flange structures provide the physical basis for the modular assembly, disassembly, and reuse of the entire device. Adjacent components (such as the top cover and the first segment, between each layer of segments, and between the end segment and the bracket) are connected via matching flanges 4 and fastened together using high-strength bolts inserted through pre-planned flange holes. To ensure the absolute sealing of the refrigerant circulation system under high pressure and prevent leakage of brine or freezing liquid from contaminating the tunnel environment and affecting the freezing effect, a low-temperature and corrosion-resistant nitrile rubber elastic sealing ring is embedded between the sealing mating surfaces of each pair of adjacent flanges 4, forming a reliable static sealing structure.

[0021] To further enhance the convenience, guidance, and structural rigidity of the connection, this embodiment employs an innovative nested combination: an outer sleeve connecting pipe 5 is provided at the lower center of the top cover 1 and the lower center of each liquid collecting and distributing ring segment 2; correspondingly, an inner sleeve connecting pipe 6, whose inner diameter precisely matches that of the outer sleeve connecting pipe 5, is provided at the upper center of each liquid collecting and distributing ring segment 2 and the upper center of the bracket 3. During installation, the outer sleeve connecting pipe 5 of the upper component (such as the top cover or upper segment) is precisely sleeved onto the outside of the inner sleeve connecting pipe 6 of the lower component (such as the lower segment or bracket), achieving an inside-outside nested combination, providing quick initial guidance and positioning for installation, and ensuring that the components are quickly put into place. After the flange bolts are tightened, the sleeve fit further eliminates the potential risk of loosening at the connection.

[0022] Taking into account that during the freezing process, the gas dissolved in the low-temperature circulating fluid may precipitate due to the decrease in temperature and accumulate at the top cover to form air blockage, affecting the freezing efficiency and even causing the risk of local overheating, this embodiment specially provides an air release valve 7 at the top center or edge of the top cover 1 to safely discharge the non-condensable gas accumulated in the top cover chamber, thereby ensuring the smooth circulation of the refrigerant in the entire circuit and efficient heat exchange, and ensuring that the freezing curtain is formed evenly.

[0023] The core functional piping of the distribution ring is carried by the distribution ring segments 2. Each segment consists of a vertical main channel—a connecting pipe 21—which serves as the main channel for the upward and downward flow of refrigerant. Two horizontal hose connectors 22, arranged perpendicularly around the circumferential sidewalls of the connecting pipe 21, connect the freezing pipes. To prevent the hoses from loosening due to fluid pressure fluctuations or accidental pulling, each hose connector 22 is machined with a captive thread 23 on the outer wall of the pipe. This ensures that the flexible hose connector has excellent pull-out resistance, significantly improving the safety and reliability of the connection.

[0024] The bottom bracket 3 plays the role of the installation and fixing basis of the liquid collecting and distributing ring device. Its main body is a vertical main pipe connector 31. In order to ensure the stability and verticality of the device when installed at any angle, on uneven ground or curved surface in the tunnel, three outward obliquely extending legs 32 are fixedly set on the outer side of the circumference of the main pipe connector 31, so that it can be firmly supported on the surface of the tunnel pipe segment or the preset platform, providing strong anti-overturning support and vibration attenuation capabilities for the entire towering liquid collecting and distributing ring device, ensuring its long-term operation stability in the complex operating environment of the tunnel.

[0025] This embodiment addresses the problems of poor welding quality stability (prone to defects such as incomplete fusion and slag inclusions) caused by extensive on-site welding in traditional manifolds for freezing communication channels in ultra-large-diameter shield tunnels; severe welding fume pollution in the work environment (affecting the health of construction workers and posing explosion hazards); and the difficulty of disassembling the manifold and freezing pipes after welding, resulting in their inability to be reused (resulting in high material costs and wasted resources). By utilizing stainless steel components and employing high-precision flanges with sealing rings, a modular hydraulic locking structure, or a standard prefabricated pipe joint quick-connect system, on-site welding is completely eliminated. This significantly improves the reliability and sealing of the manifold connections, ensuring efficient and leak-free refrigerant circulation, and significantly improves the work environment, eliminating welding fume, reducing ventilation pressure, and enhancing construction safety. Furthermore, it enables rapid, non-destructive disassembly and efficient reuse of the entire manifold assembly, significantly reducing material consumption and construction costs for individual projects. This device solves the bottleneck of traditional processes, comprehensively guarantees the uniformity, integrity and controllability of the formation of the freezing curtain, and provides core technical support for the safe, green, economical and high-quality construction of freezing communication channels in ultra-large diameter shield tunnels under complex geological conditions.

[0026] The above embodiments and accompanying drawings are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. The present invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions, or substitutions made by those skilled in the art within the spirit and scope of the present invention do not depart from the spirit of the present invention and are intended to fall within the scope of the claims. Other related technical structures not fully disclosed in the present invention constitute prior art in the art.

Claims

1. A plug-in combined liquid distribution ring for freezing communication channels in ultra-large diameter shield tunnels, characterized by: The invention comprises a top cover (1), one or more liquid collecting and distributing ring segments (2) and a bracket (3) which are fixedly connected in sequence from top to bottom. The lower end of the top cover (1), the upper and lower ends of the liquid collecting and distributing ring segment (2) and the upper end of the bracket (3) are all fixedly provided with connecting flanges (4) and are fixedly connected by bolts. A sealing ring is provided between adjacent flanges.

2. The plug-in combined liquid distribution ring for freezing communication channel of ultra-large diameter shield tunnel according to claim 1 is characterized by: An outer sleeve connecting pipe (5) is provided at the lower ends of the top cover (1) and the liquid collecting and distributing ring assembly (2), and an inner sleeve connecting pipe (6) is provided at the upper ends of the liquid collecting and distributing ring assembly (2) and the bracket (3). The outer sleeve connecting pipe (5) and the inner sleeve connecting pipe (6) are nested in combination.

3. The plug-in combined liquid distribution ring for freezing communication channel of ultra-large diameter shield tunnel according to claim 1 is characterized by: An air release valve (7) is provided at the upper end of the top cover (1) for releasing air accumulated during the freezing process.

4. The plug-in combined liquid distribution ring for freezing communication channel of ultra-large diameter shield tunnel according to claim 1 is characterized by: The liquid collecting and distributing ring assembly (2) comprises a vertical connecting pipe (21) and a plurality of horizontal hose connectors (22) connected to freezing pipes. The hose connectors (22) are arranged on the side wall of the connecting pipe (21) and can be connected in multiple directions.

5. The plug-in combined liquid distribution ring for freezing communication channel of ultra-large diameter shield tunnel according to claim 4 is characterized in that: The outer wall of the hose connector (22) is provided with an anti-falling thread (23).

6. The plug-in combined liquid distribution ring for freezing communication channel of ultra-large diameter shield tunnel according to claim 1 is characterized by: The bracket (3) comprises a vertical main pipe connector (31) and a plurality of supporting legs (32), wherein the supporting legs (32) are fixedly arranged outside the main pipe connector (31) and the number of the supporting legs (32) is not less than three.

7. The plug-in combined type liquid distribution ring for freezing communication channel of ultra-large diameter shield tunnel according to claim 1 is characterized by: The top cover (1), the liquid collecting and distributing ring assembly (2) and the bracket (3) are made of stainless steel.

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