Tunnel pipe shed and rapid connection construction method based on pipe expansion method

Abstract

The application discloses a tunnel pipe shed based on an expanding pipe method and a quick connection construction method, which comprises multiple groups of pipe shed connecting bodies, each group of pipe shed connecting bodies comprises standard pipe sections connected in front and back directions in an axial direction and inner sleeve pipes, wherein the standard pipe section is a pipe body with open ends in front and back directions, the pipe body is provided with expanding sections at the front and back ends, annular grooves are formed in the inner walls of the expanding sections in the front and back directions, the inner sleeve pipe is a steel pipe with open ends, an annular convex rib is formed on the outer wall of the pipe body of the inner sleeve pipe and close to the front and back ends and surrounds the pipe body, the rear end of the inner sleeve pipe is coaxially sleeved with the expanding section at the front end of the standard pipe section, and the annular convex rib at the rear end is matched with the annular groove in the expanding section. When the tunnel pipe shed is used, the on-site positioning is performed, the mechanical interlocking and interference fit composite connection structure of the annular convex rib and the annular groove is used, there is no cross-section weakening problem, there is no welding residual stress and base material damage, and the connection performance is stable and reliable.

Description

Technical Field

[0001] This invention belongs to the field of tunnel and underground engineering construction technology, specifically relating to a tunnel pipe roof and rapid connection construction method based on the expansion pipe method. Background Technology

[0002] Pipe roof support is the most crucial and commonly used advanced support method when tunnels traverse fault fracture zones, shallow buried sections, and water-rich soft strata, among other adverse geological formations. It effectively constrains surrounding rock deformation, prevents face collapse and water / mud inrush disasters, and ensures tunnel construction safety. Due to the limited construction space within the tunnel, single pipe roof steel pipes cannot be prefabricated and installed as a single unit. Typically, standard pipe sections of 3-6m are spliced ​​together to form the designed length of the pipe roof steel pipe. The quality of the pipe section connections and the construction efficiency directly determine the overall performance and construction period of the pipe roof support.

[0003] Currently, pipe roof sections are mainly connected using two methods: threaded connections and welding connections. Both methods have intractable technical drawbacks in engineering practice. Threaded connections require precision machining of internal and external threads at both ends of the steel pipe, making on-site alignment and tightening difficult and slow. Threading weakens the steel pipe cross-section, reducing the overall bending stiffness and load-bearing capacity of the pipe roof. During the pipe roof jacking process, the impact and vibration loads from large-tonnage drilling rigs can easily cause thread stripping and failure, leading to pipe section connection failure and engineering accidents. Welding connections place extremely high demands on the workspace and the skill level of the workers. The welding time for a single pipe section can be as long as 20-30 minutes, resulting in very low construction efficiency. The high temperature of welding can cause changes in the metallographic structure of the steel pipe base material, generating residual welding stress, which increases the brittleness of the steel pipe and makes it prone to cracking. High-temperature welding operations in water-rich and confined spaces inside tunnels pose serious safety hazards such as electric shock and fire. Welding fumes can also cause occupational health hazards in confined spaces. At the same time, the on-site welding quality is greatly affected by the environment, making it impossible to achieve comprehensive non-destructive testing. Welding defects are difficult to detect, resulting in large quality dispersion and easily leading to structural safety hazards in the pipe roof support system.

[0004] Expansion joint technology, as a mature mechanical connection process, has been widely used in the manufacturing of boilers and heat exchangers. It utilizes the difference between the plastic deformation and elastic deformation of metals to achieve a tight fit and reliable connection between pipe fittings. However, the construction conditions of tunnel pipe roofs are fundamentally different from those of industrial equipment manufacturing. The steel pipes in the pipe roof need to withstand the axial load of long-distance jacking and the radial bending load of the surrounding rock. Moreover, the on-site connection work needs to be completed in the complex environment of the tunnel, which is confined, humid, and dusty. Existing expansion joint technology lacks an adaptation design for the construction conditions of pipe roofs. The industry has not yet formed a systematic construction method and supporting equipment that can be directly applied to the connection of long-distance, multi-segment steel pipes in tunnel pipe roofs. The related technical field is still in a blank state. Summary of the Invention

[0005] The purpose of this invention is to provide a tunnel pipe roof and a rapid connection construction method based on the expansion pipe method. The method involves on-site positioning and a composite connection structure with mechanical interlocking and interference fit of annular ribs and annular grooves. This eliminates the cross-sectional weakening problem caused by thread processing, and avoids residual stress and base material damage caused by welding operations, resulting in stable and reliable connection performance.

[0006] The present invention adopts the following technical solution: a tunnel pipe roof based on the expansion pipe method, comprising multiple sets of pipe roof connectors, each set of pipe roof connectors comprising a standard pipe section and an inner sleeve connected axially front and rear, wherein the standard pipe section is a pipe body with open front and rear ends, and expansion joint sections are provided at both front and rear ends of the pipe body; annular grooves are provided on the inner walls of the front and rear expansion joint sections. The inner sleeve is a steel pipe with open ends. On the inner sleeve, near the front and rear ends of the outer wall, there is a ring-shaped rib machined around the pipe body. The rear end of the inner sleeve is coaxially fitted into the expansion joint section at the front end of the standard pipe section. The ring-shaped rib at this end matches the ring-shaped groove in the expansion joint section. Multiple sets of pipe roof connectors are connected sequentially upwards along the axis. Between two adjacent sets of pipe roof connectors, the inner sleeve of the first set of pipe roof connectors is coaxially fitted into the standard pipe section of the second set of pipe roof connectors, and the corresponding annular ribs are nested in the annular grooves. In the last set of pipe roof connectors, the rear end of its inner sleeve is coaxially fitted into a standard pipe section, which is the end connector.

[0007] Furthermore, the length of the inner sleeve fitted in the standard pipe section is consistent with the length of the expansion joint section in which it is located, and the ends of the two standard pipe sections fitted on the same inner sleeve are fitted together.

[0008] Furthermore, a flange is installed at the rear end of the end connector.

[0009] This invention also discloses a rapid connection construction method for tunnel pipe roofs based on the expansion tube method. The connection method for a tunnel pipe roof based on the expansion tube method described above is as follows: Step 1: Drill holes for pipe roof in the surrounding rock and fix the standard pipe sections of the first set of pipe roof connectors behind the surrounding rock. The fixing height is consistent with the height of the pipe roof drilling, and the horizontal axis of the standard pipe section is coaxial with the horizontal axis of the pipe roof drilling. Step 2: Insert the front end of the inner sleeve of the first set of pipe roof connectors coaxially into the rear expansion section of the standard pipe section, with the position of the annular rib corresponding to the position of the annular groove, so that the annular rib is embedded in the annular groove. Step 3: Coaxially fit the standard pipe section in the next set of pipe roof connectors onto the rear end of the inner sleeve in the first set of pipe roof connectors until the annular groove in the standard pipe section and the annular rib at the rear end of the inner sleeve are aligned axially. Step 4: Repeat steps 1 to 3, and in the last set of pipe roof connectors, coaxially fit the rear end of its inner sleeve into a standard pipe section, and sequentially complete the connection between multiple sets of pipe roof connectors to obtain a tunnel pipe roof. Step 5: Push the tunnel pipe roof from Step 4 axially forward into the pipe roof borehole until the front end of the tunnel pipe roof reaches the bottom of the pipe roof borehole. Step 6: Install the grouting flange at the rear end of the end connector and connect the grouting system; inject grout into the end connector, the grout flows forward sequentially and overflows from the side walls of each standard pipe section, and inject grout into the tunnel pipe roof and the gap between the borehole and the surrounding rock of the tunnel pipe roof.

[0010] Further, in step two, the specific steps are as follows: a single-head hydraulic tube expander is selected, and the expansion rod of the expander is extended into the inner sleeve from the rear end of the inner sleeve, so that the expansion head is located in the cross section where the annular rib is located in the axial direction, and the circumferential center line of the expansion head is the same as the circumferential center line of the annular rib. The expansion force is applied to the expansion head in stages. After reaching the design pressure, the pressure is maintained, causing the inner sleeve wall to undergo radial outward plastic expansion. This also causes the expansion section wall of the standard pipe section to undergo radial outward plastic deformation, resulting in a tight fit between the inner wall of the standard pipe section and the outer wall of the inner sleeve. After the pressure is maintained, the expansion force is removed in stages. Both the inner sleeve and the standard pipe section undergo elastic retraction and tightening. The annular rib has undergone plastic deformation and is embedded in the annular groove, forming a mechanical interlock and interference fit.

[0011] Furthermore, in step two, expansion force is applied to the expansion head in stages, and pressure is maintained after the design pressure is reached; after the pressure is maintained, the expansion force is removed in stages.

[0012] Furthermore, standard pipe sections and inner sleeves are prefabricated before drilling for the pipe roof.

[0013] The beneficial effects of this invention are: 1. Prefabrication reduces the construction period of tunnel pipe roofs to only two core processes—positioning and expansion—on-site, significantly improving efficiency and making it particularly suitable for projects with extremely tight deadlines, such as disaster relief. 2. The composite connection structure, achieved through mechanical interlocking and interference fit between the annular ribs and annular grooves, eliminates the cross-sectional weakening caused by threading, and avoids residual stress and base material damage from welding. This results in stable and reliable connection performance and a comprehensive improvement in support quality. 3. No high-temperature welding is required throughout the construction process, completely avoiding the safety hazards of electric shock and fire in water-rich strata. Furthermore, the absence of welding fume pollution significantly reduces occupational health risks in the confined space of the tunnel. The construction requires only a small hydraulic pipe expander, making it suitable for the limited construction space within tunnels. It requires minimal technical skills from workers, eliminating the need for certified welders and significantly reducing on-site workload and labor costs. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a component structure in a tunnel pipe roof based on the tube expansion method; Figure 2 This is a schematic diagram of a tunnel pipe roof based on the expansion tube method; Among them: 1. Standard pipe section; 2. Inner sleeve; 3. Annular groove; 4. Annular rib. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0016] This invention discloses a tunnel pipe roof based on the expansion method, such as... Figure 1 As shown, the system includes multiple sets of pipe roof connectors. Each set of pipe roof connectors includes a standard pipe section 1 and an inner sleeve 2. The standard pipe section 1 is a pipe body with open ends, and expansion joint sections are provided at both ends of the pipe body. In each expansion joint section, an annular groove 3 is formed around the inner wall of the pipe body. The length of the expansion joint section is 200mm~400mm, preferably 300mm.

[0017] The aforementioned inner sleeve 2 is a seamless steel pipe with open ends. On the outer wall of the inner sleeve 2, near both ends, a ring-shaped rib 4 is machined around the circumference of the pipe body. One end of the inner sleeve 2 is coaxially fitted into the expansion joint section within the standard pipe section 1. The ring-shaped rib 4 at this end matches the ring-shaped groove 3 within the standard pipe section 1. The height of the ring-shaped rib 4 matches the depth of the ring-shaped groove 3; the width of the ring-shaped rib 4 matches the width of the ring-shaped groove 3. The edges of the ring-shaped rib 4 are rounded.

[0018] like Figure 2 As shown, multiple sets of pipe roof connectors are connected sequentially to form a tunnel pipe roof; between two adjacent sets of pipe roof connectors, the inner sleeve 2 in the first set of pipe roof connectors is coaxially fitted into the standard pipe section 1 of the second set of pipe roof connectors, and the corresponding annular rib 4 is nested in the annular groove 3.

[0019] The length of the inner sleeve 2 fitted in the standard pipe section 1 is consistent with the length of the expansion joint section in which it is located, and the ends of the two inner sleeves 2 fitted in the same standard pipe section 1 are fitted together.

[0020] The inner sleeve 2 can be 500mm or 600mm long, with a wall thickness of not less than 8mm; its material hardness is HBW30~HBW50 higher than that of the standard pipe section 1. The outer diameter of the inner sleeve 2 is 0.5mm~1mm smaller than the inner diameter of the standard pipe section 1 to ensure smooth on-site connection. The length of a single standard pipe section 1 is 3m~6m, suitable for the construction space inside the tunnel, and multiple grouting holes are arranged on the pipe body.

[0021] This invention also discloses a rapid connection construction method for tunnel pipe roofs based on the expansion tube method. The construction method for a tunnel pipe roof based on the expansion tube method described above is as follows: Step 1: Advanced drilling construction: Pipe roof drilling rigs are used to drill pipe roof holes in the surrounding rock. The hole diameter is 20mm~30mm larger than the outer diameter of the pipe roof connector, and the drilling depth meets the design requirements. After the hole is formed, high-pressure air is used to clean the hole to ensure that there is no sediment in the hole, the hole wall is straight, and there is no obvious diameter reduction or hole collapse.

[0022] The first set of pipe roof connectors is aligned, and the standard pipe section 1 of the first set of pipe roof connectors is fixed behind the surrounding rock. The fixing height is consistent with the height of the pipe roof borehole, and the horizontal axis of the standard pipe section 1 is coaxial with the horizontal axis of the pipe roof borehole, thus completing the initial fixing of the standard pipe section 1.

[0023] Specifically, a support plate can be set on the pipe roof construction platform behind the surrounding rock, and an upward-facing V-shaped bracket can be erected on the plate. The V-shaped bracket is set along the front and back direction, and the standard pipe section 1 is placed and fixed inside the V-shaped bracket to achieve its positioning and fixation.

[0024] Step 2: Insert the front end of the inner sleeve 2 of the first set of pipe roof connectors coaxially into the rear expansion joint section of the standard pipe section 1, ensuring that the annular rib 4 and the annular groove 3 are aligned, so that the annular rib 4 is embedded in the annular groove 3. The insertion depth of the inner sleeve 2 is consistent with the length of the expansion joint section, so that one section of the inner sleeve 2 is located in the expansion joint section, and the annular rib 4 and the annular groove 3 are aligned. Use an inside micrometer and a coaxiality calibration piece to verify the coaxiality of the standard pipe section 1 and the inner sleeve 2, ensuring that the coaxiality deviation is no greater than 0.2 mm.

[0025] The aforementioned standard pipe section 1 and inner sleeve 2 are prefabricated as follows: Based on the tunnel pipe roof design parameters, standard pipe section 1 is fabricated using seamless steel pipe conforming to GB / T8163, with a single section length of 3m~6m, suitable for the construction space inside the tunnel. Expansion joint sections are pre-installed at both ends of each standard pipe section 1, with a length of not less than 200mm.

[0026] The inner sleeve 2 is prefabricated synchronously. The inner sleeve 2 is made of seamless steel with a wall thickness of not less than 8mm. The material hardness is HBW30~HBW50 higher than the standard pipe section. The outer diameter of the inner sleeve 2 is 0.5mm~1mm smaller than the inner diameter of the standard pipe section 1 to ensure smooth on-site connection. Annular ribs 4 are machined on the outer walls of both ends of the inner sleeve 2, corresponding to the positions of the annular grooves 3 in the standard pipe section 1. The height and width of the annular ribs 4 match the depth and width of the annular grooves 3. The difference between the outer diameter of the inner sleeve 2 and the inner diameter of the standard pipe section 1 is the height of the annular ribs 4. The number of annular ribs 4 at each end is consistent with the number of annular grooves 3 in the standard pipe section 1 at that end. The edges of the annular ribs 4 are rounded.

[0027] Step 3: Coaxially fit the standard pipe section 1 in the next set of pipe roof connectors onto the rear end of the inner sleeve 2 in the first set of pipe roof connectors until the annular groove 3 in the standard pipe section 1 and the annular rib 4 at the rear end of the inner sleeve 2 are aligned axially. The assembly process of inner sleeve 2 and standard pipe section 1 is as follows: A single-head hydraulic tube expander is selected, and the expansion rod of the expander is inserted into the inner sleeve 2 from the rear end. The position of the expansion rod is adjusted so that the expansion head is located axially at the section where the annular rib 4 is located, and the circumferential centerline of the expansion head coincides with the circumferential centerline of the annular rib 4. The hydraulic pump station is started, and the expansion head is pressurized in stages with an initial pressure of 10MPa, gradually increasing to the design pressure of 60MPa, and then holding the pressure for 30s after reaching the design pressure. The expansion head is driven by hydraulic pressure to expand radially outward uniformly, causing the inner sleeve 2 pipe wall to undergo radial outward plastic expansion, which in turn causes the expansion section of the standard pipe section 1 to undergo radial outward plastic deformation, resulting in a tight fit between the inner wall of the standard pipe section 1 and the outer wall of the inner sleeve 2. After the pressure holding is completed, the expansion force is released in stages, with each pressure reduction of 10MPa and an interval of 5s. Both the inner sleeve 2 and the standard pipe section 1 undergo elastic retraction, and the annular rib 4 has undergone plastic deformation, firmly embedded in the annular groove 3, forming a mechanical interlock and interference fit, thus completing the expansion connection of the first set of pipe roof connectors.

[0028] Step 4: Repeat steps 1 to 3, and in the last set of pipe roof connectors, coaxially fit the rear end of the inner sleeve 2 into a standard pipe section 1, and sequentially complete the connection between multiple sets of pipe roof connectors to obtain a tunnel pipe roof. Step 5: Push the tunnel pipe roof from Step 4 axially forward into the pipe roof borehole until the front end of the tunnel pipe roof reaches the bottom of the pipe roof borehole. Step 6: Install the grouting flange and the high-pressure ball valve at the end of the end connector and connect the grouting system; inject grout into the end connector, the grout flows forward sequentially and overflows from the side wall of each standard pipe section 1, and inject grout into the tunnel pipe roof and the gap between the borehole and the tunnel pipe roof.

[0029] The grouting material used is P.O42.5 grade ordinary Portland cement, with a water-cement ratio controlled at 0.8:1 to 1:1. The final grouting pressure is controlled at 2MPa to 3MPa, and the pressure holding time is not less than 10 minutes. When the grouting pressure of a single hole stably reaches the design final pressure and the grouting volume reaches more than 80% of the design calculation value, the grouting operation of that tunnel pipe roof can be ended, completing all construction procedures for a single tunnel pipe roof.

Claims

1. A tunnel pipe roof based on the expansion method, characterized in that, It includes multiple sets of pipe roof connectors. Each set of pipe roof connectors includes a standard pipe section (1) and an inner sleeve (2) that are connected axially from front to back. The standard pipe section (1) is a pipe body with open ends at both the front and back. Both ends of the pipe body are provided with expansion joint sections. An annular groove (3) is provided on the inner wall of each expansion joint section. The inner sleeve (2) is a steel pipe with open ends. On the outer wall of the inner sleeve (2) near the front and rear ends, there is an annular rib (4) machined around the pipe body. The rear end of the inner sleeve (2) is coaxially sleeved in the expansion joint section at the front end of the standard pipe section (1). The annular rib (4) at this end matches the annular groove (3) in the expansion joint section. Multiple sets of pipe roof connectors are connected axially in sequence. Between two adjacent sets of pipe roof connectors, the inner sleeve (2) of the first set of pipe roof connectors is coaxially fitted into the standard pipe section (1) of the second set of pipe roof connectors, and the corresponding annular rib (4) is nested in the annular groove (3). In the last set of pipe roof connectors, the rear end of its inner sleeve (2) is coaxially fitted into a standard pipe section (1), which is the end connector.

2. The special device for rapid connection of tunnel pipe roof based on the expansion tube method as described in claim 1, characterized in that, The length of the inner sleeve (2) fitted into the standard pipe section (1) is consistent with the length of the expansion joint section in which it is located, and the ends of the two standard pipe sections (1) fitted onto the same inner sleeve (2) are attached to each other.

3. A special device for rapid connection of tunnel pipe roofs based on the expansion pipe method as described in claim 2, characterized in that, A flange is installed at the rear end of the end connector.

4. The method for rapid connection construction of tunnel pipe roof based on the expansion method as described in claim 1, wherein the tunnel pipe roof is based on the expansion method as described in any one of claims 1-3, characterized in that, The connection method is as follows: Step 1: Drill holes for pipe roofs on the surrounding rock and fix the standard pipe section (1) of the first set of pipe roof connectors behind the surrounding rock. The fixing height is consistent with the height of the pipe roof drilling, and the horizontal axis of the standard pipe section (1) is coaxial with the horizontal axis of the pipe roof drilling. Step 2: Insert the front end of the inner sleeve (2) of the first set of pipe roof connectors coaxially into the rear expansion section of the standard pipe section (1), and make the position of the annular rib (4) correspond to the position of the annular groove (3), so that the annular rib (4) is embedded in the annular groove (3). Step 3: Coaxially sleeve the standard pipe section (1) in the next set of pipe roof connectors onto the rear end of the inner sleeve (2) in the first set of pipe roof connectors until the annular groove (3) in the standard pipe section (1) and the annular rib (4) at the rear end of the inner sleeve (2) are aligned axially. Step 4: Repeat steps 1 to 3, and in the last set of pipe roof connectors, coaxially fit the rear end of the inner sleeve (2) into a standard pipe section (1), and sequentially complete the connection between multiple sets of pipe roof connectors to obtain a tunnel pipe roof. Step 5: Push the tunnel pipe roof from Step 4 axially forward into the pipe roof borehole until the front end of the tunnel pipe roof reaches the bottom of the pipe roof borehole; Step 6: Install the grouting flange at the rear end of the end connector and connect the grouting system; inject grout into the end connector, the grout flows forward in sequence and overflows from the side wall of each of the standard pipe sections (1), and inject grout into the tunnel pipe roof and the gap between the borehole and the surrounding rock of the tunnel pipe roof.

5. The method for rapid connection construction of tunnel pipe roofs based on the expansion pipe method as described in claim 4, characterized in that, In step two, the specific steps are as follows: a single-head hydraulic tube expander is selected, and the expansion rod of the expander is inserted into the inner sleeve (2) from the rear end of the inner sleeve (2), and the expansion head is located in the axial direction at the cross section where the annular rib (4) is located, and the circumferential center line of the expansion head is the same as the circumferential center line of the annular rib (4). The expansion force is applied to the expansion head in stages. After reaching the design pressure, the pressure is maintained, causing the inner sleeve (2) wall to undergo radial outward plastic expansion, and causing the expansion section wall of the standard pipe section (1) to undergo radial outward plastic deformation. The inner wall of the standard pipe section (1) is tightly fitted with the outer wall of the inner sleeve (2). After the pressure is maintained, the expansion force is removed in stages. Both the inner sleeve (2) and the standard pipe section (1) undergo elastic retraction and clamping. The annular rib (4) has undergone plastic deformation and is embedded in the annular groove (3), forming a mechanical interlock and interference fit.

6. The method for rapid connection construction of tunnel pipe roofs based on the expansion pipe method as described in claim 5, characterized in that, In step two, expansion force is applied to the expansion head in stages, and pressure is maintained after the design pressure is reached; after the pressure is maintained, the expansion force is removed in stages.

7. The method for rapid connection construction of tunnel pipe roofs based on the expansion pipe method as described in claim 6, characterized in that, Before drilling for the pipe roof, prefabricate standard pipe sections (1) and inner sleeves (2).

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