Construction method and structure of variable-diameter pipe shed

Abstract

The present application relates to the technical field of building construction, and provides a construction method and structure of a variable-diameter pipe shed, comprising the following steps: S1, drilling a plurality of foundation support bottom holes in a horizontal direction at a top position of a tunnel portal, the plurality of foundation support bottom holes being evenly arranged in a circumferential direction of the tunnel portal top; S2, drilling an extension support bottom hole with a smaller diameter than the foundation support bottom hole in a horizontal direction at a bottom of the foundation support bottom hole; S3, placing a foundation support steel pipe into the foundation support bottom hole; S4, placing an extension support steel pipe into the extension support bottom hole, and connecting the foundation support steel pipe and the extension support steel pipe at their heads and tails when a designed depth is reached; and S5, grouting and reinforcing the whole pipe shed support in the foundation support steel pipe and the extension support steel pipe. The diameter of the extension support steel pipe is smaller than the diameter of the foundation support steel pipe, the lengthening support of the portal top pipe shed is realized by changing the diameter of the steel pipe, and the ductility of the pipe shed support is improved.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a construction method and structure for a variable diameter pipe shed. Background Technology

[0002] Pipe roof pre-support is typically used at the tunnel entrance in weak surrounding rock or unstable strata, with a length of about 10 meters. If deeper construction is required, the difficulty of drilling increases with the horizontal depth, and borehole collapse may occur. This not only affects the construction progress but also reduces the stability and safety of the pre-support at the top of the tunnel entrance. Summary of the Invention

[0003] The purpose of this invention is to provide a construction method and structure for a variable diameter pipe roof, so as to solve at least one or more technical problems existing in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides a construction method and structure for a variable diameter pipe roof, comprising the following steps: S1. Drill several foundation support bottom holes in the horizontal direction at the top of the tunnel gate, and the several foundation support bottom holes are evenly arranged around the top of the tunnel gate. S2. Drill an extension support bottom hole with a diameter smaller than the basic support bottom hole in the horizontal direction at the bottom of the basic support bottom hole. S3. Place the foundation support steel pipe into the foundation support bottom hole; S4. Place the extended support steel pipe into the extended support bottom hole. When the extended support steel pipe reaches the design depth, connect the basic support steel pipe and the extended support steel pipe end to end. S5. Grouting is performed in the foundation support steel pipe and the extension support steel pipe to reinforce the overall pipe roof support.

[0005] The construction length of the pipe shed is increased by using a variable diameter pipe shed composed of large-diameter foundation support steel pipes and small-diameter extension support steel pipes. After the foundation support steel pipes and extension support steel pipes are installed and connected, grouting is performed in a unified manner. This not only ensures the ductility and integrity of the variable diameter pipe shed support, but also improves the stability and safety of the surrounding rock at the top of the tunnel. This avoids the occurrence of hole collapse and ensures the progress of tunnel construction.

[0006] Further, S4 includes the following steps: S41. Use a drill rod to push the extended support steel pipe into the extended support bottom hole; S42. After the extended support steel pipe reaches the designed depth, connect the basic support steel pipe and the extended support steel pipe end to end. S43, The drill rod is withdrawn from the foundation support steel pipe.

[0007] Preferably, the foundation support steel pipe is a first foundation support steel pipe, which is a seamless steel pipe with internal threads fixedly provided on the inner side wall of one end; The extended support steel pipe is the first extended support steel pipe, which is a steel pipe with a threaded joint fixed at one end and a crescent plate inside the other end of the first extended support steel pipe to prevent slurry backflow. The head of the drill pipe is provided with an external thread, and the threaded joint is provided with internal and external threads for connecting the first foundation support steel pipe and the first extension steel pipe end to end, as well as for connecting the drill pipe and the first extension support steel pipe.

[0008] Specifically, a drill rod with external threads at its head is connected to the threaded connector, and the first extended support steel pipe is pushed into the extended support bottom hole using the drill rod. The drill rod is rotated, causing the threaded connector to connect with the internal thread of the first foundation support steel pipe, completing the end-to-end connection between the first foundation support steel pipe and the first extended support steel pipe. Then, the drill rod is reversed and disengaged from the first extended support steel pipe, exiting the first foundation support steel pipe. Finally, grouting is injected into the first foundation support steel pipe and the first extended support steel pipe to reinforce the pipe roof support.

[0009] Furthermore, the foundation support steel pipe is a second foundation support steel pipe, which is a seamless steel pipe with an inwardly tapered end. The extended support steel pipe is a second extended support steel pipe, which is a steel flower pipe with prestressed steel strands inside; one end of the second extended support steel pipe is provided with an anchor head for fixing the prestressed steel strands, and the other end of the prestressed steel strands extends to the outside of the second foundation support steel pipe.

[0010] Specifically, the second extended support steel pipe is pushed into the bottom hole of the extended support using a drill rod; after the second extended support steel pipe reaches the designed position, the drill rod is withdrawn from the second basic support steel pipe; grout is injected into the second basic support steel pipe and the second extended support steel pipe; after the grout reaches the required strength, the prestressed steel strands are tensioned and anchored, so that the basic support steel pipe and the extended support steel pipe are simultaneously stressed to ensure the stability of the pre-support of the gate.

[0011] Furthermore, the foundation support steel pipe is a third foundation support steel pipe, which is a seamless steel pipe with a keyway at one end; the third foundation support steel pipe has several sliding grooves spaced apart in the inner circumference, the sliding grooves extend axially and communicate with the keyway, and the radial depth of the keyway is greater than the radial depth of the sliding groove. The extended support steel pipe is a third extended support steel pipe, which is a steel flower pipe with a locking key at one end, and the locking key is adapted to the keyway.

[0012] Specifically, the third extension support steel pipe is pushed into the extension support bottom hole along the slide groove using a drill rod; when the locking key slides into the keyway, the drill rod is rotated to engage the locking key in the keyway, completing the end-to-end connection between the third extension support steel pipe and the third foundation support steel pipe; the drill rod is then withdrawn from the third foundation support steel pipe. Finally, grouting is injected into the third foundation support steel pipe and the third extension support steel pipe to reinforce the pipe roof support.

[0013] Furthermore, the foundation support steel pipe is a fourth foundation support steel pipe, which is a seamless steel pipe with a magnetic body pipe joint fixed at one end, and the magnetic body pipe joint is wrapped with an anti-magnetic sticker. The extended support steel pipe is the fourth extended support steel pipe, which is a steel flower pipe with a magnetic pipe joint two fixed at one end. The magnetic tube connector one and the magnetic tube connector two are magnetically attracted to each other.

[0014] The magnetic tube joint is wrapped with an anti-magnetic sticker, which protects the magnetic tube joint and effectively prevents the fourth extension support steel pipe from being attracted when it is pushed in.

[0015] Specifically, the fourth extended support steel pipe is pushed into the bottom hole of the extended support using a drill rod; when the fourth basic support steel pipe and the fourth extended support steel pipe are connected end to end, the second magnetic tube joint breaks the magnetically insulating tape on the outside of the first magnetic tube joint, causing the two magnetic tube joints to attract each other magnetically, thus completing the connection between the fourth basic support steel pipe and the fourth extended support steel pipe; the drill rod is then withdrawn from the fourth basic support steel pipe. Finally, grout is injected into the fourth basic support steel pipe and the fourth extended support steel pipe to reinforce the pipe roof support.

[0016] Preferably, the foundation support steel pipe is a fifth foundation support steel pipe, which is a seamless steel pipe with a concrete tapered pipe joint fixedly installed at one end, and the large-diameter end of the concrete tapered pipe joint is fixedly connected to the seamless steel pipe of the fifth foundation support steel pipe. The extended support steel pipe is the fifth extended support steel pipe, which is a steel flower pipe with a concrete tapered pipe joint two fixed at one end. The small diameter end of the concrete tapered pipe joint two is fixedly connected to the steel flower pipe of the fifth extended support steel pipe. The inner diameter of the small-diameter end of the first concrete tapered pipe joint is smaller than the outer diameter of the large-diameter end of the second concrete tapered pipe joint, but larger than the outer diameter of the small-diameter end of the second concrete tapered pipe joint.

[0017] Specifically, the fifth extended support steel pipe is pushed into the bottom hole of the extended support using a drill rod; after the small-diameter end of the first concrete tapered pipe joint and the large-diameter end of the second concrete tapered pipe joint are engaged to complete the connection between the first and second ends of the fifth foundation support steel pipe and the fifth extended support steel pipe, the drill rod is withdrawn from the fifth foundation support steel pipe. Then, grouting is injected into the fifth foundation support steel pipe and the fifth extended support steel pipe to reinforce the pipe roof support.

[0018] Furthermore, the foundation support steel pipe is the sixth foundation support steel pipe, which is a seamless steel pipe with several round pipes spaced apart and fixedly installed at one end along the circumference. Solid metal adhesive is installed inside the round pipes, and guide grooves are provided in the sixth foundation support steel pipe along the axial direction corresponding to the round pipes. The extended support steel pipe is the sixth extended support steel pipe. The sixth extended support steel pipe is a steel flower pipe with several solid cylinders spaced apart and fixedly installed at one end along the circumference. A gap is provided between the solid cylinders and the steel flower pipe along the radial direction. The spacing between the solid cylinders is the same as the spacing between the circular tubes, and the diameter of the solid cylinders is smaller than the inner diameter of the circular tubes.

[0019] Specifically, before the solid metal adhesive reacts with the metal, the sixth extended support steel pipe is pushed into the bottom hole of the extended support along the guide groove using a drill rod; then, the solid cylinder is pushed into the round pipe, overlapping and fitting with it. The solid metal adhesive reacts with the round pipe and the solid cylinder, bonding them together, thus completing the fixed end-to-end connection between the sixth basic support steel pipe and the sixth extended support steel pipe; the drill rod is then withdrawn from the sixth basic support steel pipe. Finally, grouting is injected into the sixth basic support steel pipe and the sixth extended support steel pipe to reinforce the pipe roof support.

[0020] Furthermore, the number of the basic support steel pipes and the extended support steel pipes are arranged according to the size of the tunnel gate and the diameter of the basic support steel pipes and the extended support steel pipes, as per the design requirements.

[0021] By adopting the above technical solution, the present invention has the following beneficial effects: The present invention provides a construction method and structure for a variable diameter pipe roof, which has the following advantages: By varying the diameter of the pipe roof support steel pipes, the pipe roof at the top of the tunnel portal is extended, preventing hole collapse. This improves the ductility and integrity of the pipe roof support and enhances the stability and safety of the portal's advanced support, thereby ensuring construction safety and progress. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a front view of the first foundation support steel pipe, the first extension support steel pipe, and the drill rod in a variable diameter pipe roof construction method and structure provided in Embodiment 1 of the present invention. Figure 2 This is a front view of the first foundation support steel pipe and the first extension support steel pipe after grouting reinforcement in a variable diameter pipe roof construction method and structure provided in Embodiment 1 of the present invention. Figure 3 This is a front view of the support section of the pipe roof at the head gate in a construction method and structure for a variable diameter pipe roof provided in Embodiment 1 of the present invention. Figure 4 This is a front view of the second foundation support steel pipe and the second extension support steel pipe in a variable diameter pipe shed construction method and structure provided in Embodiment 2 of the present invention. Figure 5 This is a front view of the second foundation support steel pipe and the second extension support steel pipe after grouting reinforcement in a variable diameter pipe roof construction method and structure provided in Embodiment 2 of the present invention. Figure 6 This is a front view of the third foundation support steel pipe and the third extension support steel pipe in a variable diameter pipe shed construction method and structure provided in Embodiment 3 of the present invention; Figure 7 This is a front view of the third foundation support steel pipe and the third extension support steel pipe after grouting reinforcement in a variable diameter pipe shed construction method and structure provided in Embodiment 3 of the present invention. Figure 8 for Figure 7 Enlarged view of point A in the middle; Figure 9 This is a front view of the fourth foundation support steel pipe and the fourth extension support steel pipe in a variable diameter pipe shed construction method and structure provided in Embodiment 4 of the present invention; Figure 10 This is a front view of the fourth foundation support steel pipe and the fourth extension support steel pipe after grouting reinforcement in a variable diameter pipe shed construction method and structure provided in Embodiment 4 of the present invention. Figure 11 This is a front view of the fifth foundation support steel pipe and the fifth extension support steel pipe in a variable diameter pipe shed construction method and structure provided in Embodiment 5 of the present invention; Figure 12 This is a front view of the fifth foundation support steel pipe and the fifth extension support steel pipe after grouting reinforcement in a variable diameter pipe shed construction method and structure provided in Embodiment 5 of the present invention; Figure 13 This is a front view of the sixth foundation support steel pipe and the sixth extension support steel pipe in a variable diameter pipe shed construction method and structure provided in Embodiment 6 of the present invention; Figure 14 This is a right view of the sixth foundation support steel pipe in a variable diameter pipe shed construction method and structure provided in Embodiment 6 of the present invention; Figure 15 for Figure 13 Enlarged view of point A in the middle; Figure 16 This is a front view of the sixth foundation support steel pipe and the sixth extension support steel pipe after grouting reinforcement in a variable diameter pipe shed construction method and structure provided in Embodiment 6 of the present invention.

[0024] Figure label: 10-First foundation support steel pipe; 11-Internal thread; 20-First extension support steel pipe; 21-Threaded joint; 22-Crescent plate; 30-Drill pipe; 31-External thread; 40-Cement grout; 50-Second foundation support steel pipe; 51-Inner closing; 60-Second extension support steel pipe; 61-Prestressed steel strand; 62-Anchor head; 70-Third foundation support steel pipe; 71-Keyway; 72-Sliding groove; 80-Third extension support steel pipe; 81-Clamping key; 90-Fourth foundation support steel pipe; 91-Magnetic pipe joint one; 110-Fourth extension support steel pipe; 111-Magnetic pipe joint two; 120-Fifth foundation support steel pipe; 121-Concrete tapered pipe joint one; 122-Steel strip one; 130-Fifth extension support steel pipe; 131-Concrete tapered pipe joint two; 132-Steel strip two; 140-Sixth foundation support steel pipe; 141-Round pipe; 142-Solid metal adhesive; 143-Guide groove; 150-Sixth extension support steel pipe; 151-Solid cylinder. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] The present invention will be further explained below with reference to specific embodiments.

[0029] This embodiment provides a construction method and structure for a variable diameter pipe shed, including the following steps: S1. Drill several foundation support bottom holes horizontally at the top of the tunnel gate. The foundation support bottom holes are evenly distributed around the top of the tunnel gate. S2. Drill an extension support bottom hole with a diameter smaller than the foundation support bottom hole in the horizontal direction at the bottom of the foundation support bottom hole. S3. Place the foundation support steel pipe into the foundation support bottom hole; S4. Place the extension support steel pipe into the bottom hole of the extension support. When the extension support steel pipe reaches the design depth, connect the foundation support steel pipe and the extension support steel pipe end to end. S5. Grouting is performed in the foundation support steel pipe and the extension support steel pipe to reinforce the overall pipe roof support.

[0030] The construction length of the pipe shed is increased by using a variable diameter pipe shed composed of large-diameter foundation support steel pipes and small-diameter extension support steel pipes. After the foundation support steel pipes and extension support steel pipes are installed and connected, grouting is performed in a unified manner. This not only ensures the ductility and integrity of the variable diameter pipe shed support, but also improves the stability and safety of the surrounding rock at the top of the tunnel. This avoids the occurrence of hole collapse and ensures the progress of tunnel construction.

[0031] In addition, S4 includes the following steps: S41. Use drill rod 30 to push the extension support steel pipe into the extension support bottom hole; S42. After the extended support steel pipe reaches the design depth, connect the foundation support steel pipe and the extended support steel pipe end to end. S43, Drill rod 30 is removed from the foundation support steel pipe.

[0032] Example 1 like Figure 1-2 As shown, the foundation support steel pipe is the first foundation support steel pipe 10, which is a seamless steel pipe with an internal thread 11 fixedly installed on the inner side wall of one end. The extended support steel pipe is the first extended support steel pipe 20. The first extended support steel pipe 20 is a steel pipe with a threaded joint 21 fixed at one end. The other end of the first extended support steel pipe 20 is provided with a crescent plate 22 to prevent slurry backflow. The head of the drill pipe 30 is provided with an external thread 31, and the threaded joint 21 is provided with internal and external threads for the connection of the first foundation support steel pipe 10 and the first extension steel pipe 20, as well as the connection of the drill pipe 30 and the first extension support steel pipe 20.

[0033] Specifically, the drill rod 30, with external threads 31 at its head, is connected to the threaded connector 21. The drill rod 30 is used to push the first extended support steel pipe 20 into the bottom hole of the extended support. The drill rod 30 is rotated, causing the threaded connector 21 to connect with the internal threads 11 of the first foundation support steel pipe 10, completing the end-to-end connection between the first foundation support steel pipe 10 and the first extended support steel pipe 20. Then, the drill rod 30 is reversed to disengage from the first extended support steel pipe 20 and withdrawn from the first foundation support steel pipe 10. Finally, cement grout 40 is injected into the first foundation support steel pipe and the first extended support steel pipe to reinforce the pipe roof support.

[0034] like Figure 3 As shown, in this embodiment, the number of the first basic support steel pipe 10 and the first extension support steel pipe 20 are both 11, wherein the outer diameter of the first basic support steel pipe 10 is 70mm and the outer diameter of the first extension support steel pipe 20 is 50mm.

[0035] This embodiment uses threaded joint 21 to connect pipe roof support steel pipes of different diameters, which not only ensures the ductility and safety of the pipe roof, but also enhances the stability and safety of the advanced support of the gate.

[0036] Example 2 like Figure 4-5 As shown, the foundation support steel pipe is the second foundation support steel pipe 50, which is a seamless steel pipe with an inwardly tapered end 51 at one end. The extended support steel pipe is the second extended support steel pipe 60, which is a steel pipe with prestressed steel strands 61 inside; one end of the second extended support steel pipe 60 is provided with an anchor head 62 for fixing the prestressed steel strands 61, and the other end of the prestressed steel strands 61 extends to the outside of the second foundation support steel pipe 50.

[0037] Specifically, the second extension support steel pipe 60 is pushed into the extension support bottom hole using the drill rod 30; after the second extension support steel pipe 60 reaches the designed position, the drill rod 30 is withdrawn from the second foundation support steel pipe 50; cement grout 40 is injected into the second foundation support steel pipe 50 and the second extension support steel pipe 60; after the cement grout 40 reaches the strength requirements, the prestressed steel strands 61 are tensioned and anchored, so that the second foundation support steel pipe 50 and the second extension support steel pipe 60 are simultaneously stressed to ensure the stability and ductility of the pre-support of the gate.

[0038] Example 3 like Figure 6-8 As shown, the foundation support steel pipe is the third foundation support steel pipe 70, which is a seamless steel pipe with a keyway 71 at one end; the third foundation support steel pipe 70 is provided with several sliding grooves 72 at intervals in the inner circumference, the sliding grooves 72 extend along the axial direction and communicate with the keyway 71, and the radial depth of the keyway 71 is greater than the radial depth of the sliding groove 72. The extended support steel pipe is the third extended support steel pipe 80. The third extended support steel pipe 80 is a steel flower pipe with a locking key 81 at one end. The locking key 81 is adapted to the keyway 71.

[0039] Specifically, the third extension support steel pipe 80 is pushed into the extension support bottom hole along the sliding groove 72 using the drill rod 30; when the locking key 81 slides into the keyway 71, the drill rod 30 is rotated to lock the locking key 81 into the keyway 71, completing the end-to-end connection between the third extension support steel pipe 80 and the third foundation support steel pipe 70; the drill rod 30 is then withdrawn from the third foundation support steel pipe 70. Then, cement grout 40 is injected into the third foundation support steel pipe 70 and the third extension support steel pipe 80 to reinforce the pipe roof support.

[0040] In this embodiment, the connection of steel pipes with different diameters in the pipe shed is achieved through the connection of key 81 and keyway 71, thereby realizing the ductility of the pre-support of the gate and ensuring the stability and safety of the pre-support of the gate.

[0041] Example 4 like Figure 9-10 As shown, the foundation support steel pipe is the fourth foundation support steel pipe 90. The fourth foundation support steel pipe 90 is a seamless steel pipe with a magnetic body pipe joint 91 fixed at one end. The magnetic body pipe joint 91 is wrapped with an anti-magnetic sticker. The extended support steel pipe is the fourth extended support steel pipe 110, which is a steel flower pipe with a magnetic pipe joint 111 at one end. Magnetic tube connector 191 and magnetic tube connector 211 are magnetically attracted to each other.

[0042] The magnetic tube connector 91 is wrapped with an anti-magnetic sticker, which protects the magnetic tube connector and effectively prevents adsorption of the fourth extension support steel pipe 110 when it is pushed in.

[0043] Specifically, the fourth extension support steel pipe 110 is pushed into the extension support bottom hole using drill rod 30; when the fourth foundation support steel pipe 90 and the fourth extension support steel pipe 110 are connected end to end, the magnetic tube joint 2 111 breaks the magnetic shielding sticker outside the magnetic tube joint 1 91, causing the two magnetic tube joints to attract each other magnetically, thus completing the connection between the fourth foundation support steel pipe 90 and the fourth extension support steel pipe 110; the drill rod 30 is then withdrawn from the fourth foundation support steel pipe 90. Then, cement grout 40 is injected into the fourth foundation support steel pipe 90 and the fourth extension support steel pipe 110 to reinforce the pipe roof support.

[0044] In this embodiment, the outer diameter of the magnetic tube connector 211 is similar to the inner diameter of the magnetic tube connector 191, ensuring that the two connectors can achieve magnetic attraction after the magnetic insulation patch is broken, thereby ensuring the connection of steel pipes of different diameters in the pipe shed, so as to realize the extensibility and stability of the advanced support of the horse-head gate.

[0045] Example 5 like Figure 11-12 As shown, the foundation support steel pipe is the fifth foundation support steel pipe 120. The fifth foundation support steel pipe 120 is a seamless steel pipe with a concrete tapered pipe joint 121 fixedly installed at one end. The large-diameter end of the concrete tapered pipe joint 121 is fixedly connected to the seamless steel pipe of the fifth foundation support steel pipe 120. The extended support steel pipe is the fifth extended support steel pipe 130. The fifth extended support steel pipe 130 is a steel flower pipe with a concrete tapered pipe joint 131 fixed at one end. The small diameter end of the concrete tapered pipe joint 131 is fixedly connected to the steel flower pipe of the fifth extended support steel pipe 130. The inner diameter of the small-diameter end of the concrete tapered pipe joint 121 is smaller than the outer diameter of the large-diameter end of the concrete tapered pipe joint 131, but larger than the outer diameter of the small-diameter end of the concrete tapered pipe joint 131.

[0046] In this embodiment, the concrete tapered pipe joint 121 is welded and fixed to the seamless steel pipe of the fifth foundation support steel pipe 120 by steel strip 122; the concrete tapered pipe joint 131 is welded and fixed to the steel pipe of the fifth extension support steel pipe 130 by steel strip 132.

[0047] Specifically, the fifth extension support steel pipe 130 is pushed into the bottom hole of the extension support using drill rod 30; after the small-diameter end of concrete tapered pipe joint 121 and the large-diameter end of concrete tapered pipe joint 131 are snapped together to complete the connection between the first and last ends of the fifth foundation support steel pipe 120 and the fifth extension support steel pipe 130, drill rod 30 is withdrawn from the fifth foundation support steel pipe 120. Then, cement grout 40 is injected into the fifth foundation support steel pipe 120 and the fifth extension support steel pipe 130 to reinforce the pipe roof support.

[0048] In this embodiment, tapered pipe joints of different diameters are used to connect the foundation support steel pipe and the extension support steel pipe end to end, thereby realizing the connection of support steel pipes of different diameters and ensuring the ductility and stability of the pipe roof support.

[0049] Example 6 like Figure 13-16 As shown, the foundation support steel pipe is the sixth foundation support steel pipe 140. The sixth foundation support steel pipe 140 is a seamless steel pipe with several round pipes 141 spaced apart and fixedly installed at one end along the circumference. Solid metal adhesive 142 is installed inside the round pipes 141. Guide grooves 143 are provided in the sixth foundation support steel pipe 140 along the axial direction corresponding to the round pipes 141. The extended support steel pipe is the sixth extended support steel pipe 150. The sixth extended support steel pipe 150 is a steel flower pipe with several solid cylinders 151 spaced apart and fixedly installed at one end along the circumference. A gap is provided between the solid cylinders 151 and the steel flower pipe along the radial direction. The spacing between solid cylinders 151 is the same as the spacing between circular tubes 141, and the diameter of solid cylinders 151 is smaller than the inner diameter of circular tubes 141.

[0050] Specifically, before the solid metal adhesive 142 reacts with the metal, the sixth extension support steel pipe 150 is pushed into the extension support bottom hole along the guide groove 143 using the drill rod 30; then, the solid cylinder 151 is pushed into the round pipe 141, overlapping and fitting with the round pipe 141. After the solid metal adhesive 142 reacts with the round pipe 141 and the solid cylinder 151, they bond together, completing the end-to-end connection of the sixth foundation support steel pipe 140 and the sixth extension support steel pipe 150; the drill rod 30 is then withdrawn from the sixth foundation support steel pipe 140. Finally, cement grout 40 is injected into the sixth foundation support steel pipe 140 and the sixth extension support steel pipe 150 to reinforce the pipe roof support.

[0051] This embodiment utilizes the delayed reaction characteristics of solid metal adhesive 142 to fix and connect steel pipes of different diameters together, thereby achieving the ductility and integrity of variable diameter pipe roof support.

[0052] The quantity of basic support steel pipes and extension support steel pipes shall be arranged according to the design requirements based on the size of the tunnel gate and the diameter of the basic support steel pipes and extension support steel pipes.

[0053] The diameter, quantity, and layout of the foundation support steel pipes and extension support steel pipes in the variable diameter pipe roof support provided in Examples 2-6 are all the same as those in Example 1. Figure 3 The same as shown.

[0054] The present invention provides a construction method and structure for a variable diameter pipe roof, which has the following advantages: By varying the diameter of the pipe roof support steel pipes, the pipe roof at the top of the tunnel portal is extended, preventing hole collapse. This improves the ductility and integrity of the pipe roof support and enhances the stability and safety of the portal's advanced support, thereby ensuring construction safety and progress.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A construction method for a variable diameter pipe roof, characterized in that, Includes the following steps: S1. Drill several foundation support bottom holes in the horizontal direction at the top of the tunnel gate, and the several foundation support bottom holes are evenly arranged around the top of the tunnel gate. S2. Drill an extension support bottom hole with a diameter smaller than the basic support bottom hole in the horizontal direction at the bottom of the basic support bottom hole. S3. Place the foundation support steel pipe into the foundation support bottom hole; S4. Place the extension support steel pipe into the bottom hole of the extension support. When the extension support steel pipe reaches the design depth, connect the basic support steel pipe and the extension support steel pipe end to end. S5. Grouting is performed in the foundation support steel pipe and the extension support steel pipe to reinforce the overall pipe roof support.

2. The construction method for the variable diameter pipe shed according to claim 1, characterized in that, S4 includes the following steps: S41. Use a drill rod to push the extended support steel pipe into the extended support bottom hole; S42. After the extended support steel pipe reaches the designed depth, connect the basic support steel pipe and the extended support steel pipe end to end. S43, The drill rod is withdrawn from the foundation support steel pipe.

3. The construction method for the variable diameter pipe shed according to claim 2, characterized in that, The foundation support steel pipe is the first foundation support steel pipe, which is a seamless steel pipe with internal threads fixedly installed on the inner side wall of one end. The extended support steel pipe is the first extended support steel pipe, which is a steel flower pipe with a threaded joint fixed at one end, and a crescent plate is installed inside the other end of the first extended support steel pipe to prevent slurry backflow. The drill pipe head is provided with an external thread, and the threaded joint is provided with internal and external threads. The internal thread of the threaded joint is used for the connection between the drill pipe and the first extended support steel pipe, and the external thread of the threaded joint is used for the end connection between the first foundation support steel pipe and the first extended steel pipe.

4. The construction method for the variable diameter pipe shed according to claim 2, characterized in that, The foundation support steel pipe is the second foundation support steel pipe, which is a seamless steel pipe with an inwardly tapered end. The extended support steel pipe is a second extended support steel pipe, which is a steel flower pipe with prestressed steel strands inside; one end of the second extended support steel pipe is provided with an anchor head for fixing the prestressed steel strands, and the other end of the prestressed steel strands extends to the outside of the second foundation support steel pipe.

5. The construction method for the variable diameter pipe shed according to claim 2, characterized in that, The foundation support steel pipe is a third foundation support steel pipe, which is a seamless steel pipe with a keyway at one end; the third foundation support steel pipe has several sliding grooves spaced apart in the inner circumference, the sliding grooves extend axially and communicate with the keyway, and the radial depth of the keyway is greater than the radial depth of the sliding groove. The extended support steel pipe is a third extended support steel pipe, which is a steel flower pipe with a locking key at one end, and the locking key is adapted to the keyway.

6. The construction method for the variable diameter pipe shed according to claim 2, characterized in that, The foundation support steel pipe is the fourth foundation support steel pipe. The fourth foundation support steel pipe is a seamless steel pipe with a magnetic body pipe joint fixedly installed on the inner side wall of one end. The magnetic body pipe joint is wrapped with an anti-magnetic sticker. The extended support steel pipe is the fourth extended support steel pipe, which is a steel flower pipe with a magnetic pipe joint two fixedly installed on the inner side wall of one end. The magnetic tube connector one and the magnetic tube connector two are magnetically attracted to each other.

7. The construction method for the variable diameter pipe shed according to claim 2, characterized in that, The foundation support steel pipe is the fifth foundation support steel pipe, which is a seamless steel pipe with a concrete tapered pipe joint fixed at one end. The large-diameter end of the concrete tapered pipe joint is fixedly connected to the seamless steel pipe of the fifth foundation support steel pipe. The extended support steel pipe is the fifth extended support steel pipe, which is a steel flower pipe with a concrete tapered pipe joint two fixed at one end. The small diameter end of the concrete tapered pipe joint two is fixedly connected to the steel flower pipe of the fifth extended support steel pipe. The inner diameter of the small-diameter end of the first concrete tapered pipe joint is smaller than the outer diameter of the large-diameter end of the second concrete tapered pipe joint, but larger than the outer diameter of the small-diameter end of the second concrete tapered pipe joint.

8. The construction method for the variable diameter pipe shed according to claim 2, characterized in that, The foundation support steel pipe is the sixth foundation support steel pipe. The sixth foundation support steel pipe is a seamless steel pipe with several round pipes spaced apart and fixedly installed at one end along the circumference. Solid metal adhesive is installed inside the round pipes. A guide groove is installed in the sixth foundation support steel pipe along the axial direction corresponding to the round pipes. The extended support steel pipe is the sixth extended support steel pipe. The sixth extended support steel pipe is a steel flower pipe with several solid cylinders spaced apart and fixedly installed on the outer side wall of one end in the circumferential direction. There is a gap between the solid cylinders and the outer side wall of the steel flower pipe of the sixth extended support steel pipe. The spacing between the solid cylinders is the same as the spacing between the circular tubes, and the diameter of the solid cylinders is smaller than the inner diameter of the circular tubes.

9. The construction method for the variable diameter pipe shed according to any one of claims 3-8, characterized in that, The number of the basic support steel pipes and the extended support steel pipes are arranged according to the size of the tunnel gate and the diameter of the basic support steel pipes and the extended support steel pipes, as per the design requirements.

Images