Construction method for pipe insertion by means of buoyancy

Abstract

A construction method for pipe insertion by means of buoyancy, wherein water is used as the medium between an outer casing pipe (2) and an inner inserted pipe (1); an inlet opening water-stop device (4) and an inlet opening limiting device (5) are mounted at the end of the outer casing pipe (2) serving as an inlet opening, and an outlet opening water-stop device (6) and an outlet opening water-stop wall (8) are mounted at the end of the outer casing pipe (2) serving as an outlet opening; limiting rollers (12) are mounted on the inner wall of the outer casing pipe (2), and inner inserted pipe end anti-collision rollers (13) are mounted at the end of the inner inserted pipe (1); finally, under the action of buoyancy, the inner inserted pipe (1) is smoothly advanced into the outer casing pipe (2), thereby solving the problems of insufficient support structure strength, poor durability, and potential damage to an external anti-corrosion layer of a pipeline in conventional pipe insertion construction methods.

Description

A buoyancy-based pipe-laying construction method Technical Field

[0001] This invention relates to the field of trenchless construction technology, and in particular to a buoyancy-based pipe-laying construction method. Background Technology

[0002] Currently, trenchless pipe jacking technology has been widely applied in municipal pipeline engineering and other fields. However, during pipeline laying, areas with complex geological conditions are often encountered, especially when pipelines need to cross rivers, highways, and railways, which places higher demands on pipeline operation safety. In recent years, the application of internal pipe laying in pipeline construction has become increasingly common, serving as an important means to solve the problem of pipelines crossing important structures.

[0003] Currently, existing internal pipe penetration projects both domestically and internationally commonly employ traditional techniques such as roller launching, pipe external wall caster installation, and pulley system propulsion. These methods are primarily suitable for projects with smaller pipe diameters, shorter penetration distances, and lower requirements for finished pipe protection. However, in internal pipe penetration construction involving large diameters, long distances, and projects with high requirements for pipe corrosion protection, these traditional methods often encounter problems such as insufficient support structure strength and poor durability, and are prone to damaging the outer anti-corrosion layer of the pipe. Therefore, it is essential to propose a novel pipe penetration construction method to address these issues.

[0004] It is understood that the above statements only provide background information related to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a buoyancy-based pipe-through construction method to overcome the problems of insufficient support structure strength and poor durability in traditional pipe-through construction methods.

[0006] To achieve the above objectives, this invention provides a buoyancy-based pipe-insertion construction method, which utilizes buoyancy to insert an inner pipe into the middle portion of an outer pipe. Specifically, it includes the following steps: S1, installing an inlet water-stop device and an inlet limiting device at one end of the outer pipe serving as the inlet, and installing an outlet water-stop device and an outlet water-stop wall at the other end of the outer pipe serving as the outlet; S2, arranging precast concrete blocks at even intervals along the axial direction at the bottom of the cavity inside the outer pipe, and installing limiting rollers on the inner wall of the outer pipe; S3, using a power system to push the end of the first section of the inner pipe into the inlet water-stop device a first predetermined distance, then constructing an inner pipe end water-stop wall at the end of the inner pipe, and installing an inner pipe end anti-collision roller at the end of the inner pipe; S4, ... S5. Water is injected between the outer and inner pipes until a predetermined water level is reached. The inner pipe continues to be connected and advanced normally. S6. When the inner pipe is advanced to the second predetermined distance before the outlet water-stop device, advancement is paused. After the anti-collision roller at the end of the inner pipe is removed, advancement continues. S7. After the inner pipe pushes out of the outlet water-stop device, advancement is paused. The water source between the outlet water-stop device and the outlet water-stop wall is drained, and the outlet water-stop wall is removed. S8. Advancement continues until the inner pipe is pushed outside the outlet of the outer pipe, completing the advancement of the inner pipe. S9. The water source between the inner pipe and the outer pipe is drained, allowing the inner pipe to fall vertically onto the precast concrete pad. S10. The water-stop wall at the end of the inner pipe is removed, completing the buoyancy pipe construction.

[0007] Preferably, the inlet water-stopping device includes: an inlet flange, an inlet rubber water-stopping curtain, an inlet water-stopping baffle, and multiple inlet connectors.

[0008] The inlet flange is an annular structure with a T-shaped cross-section. Its T-shaped longitudinal beam is installed on the inner wall of the inlet of the outer sleeve. The T-shaped transverse beam is connected to the inlet water-stop baffle through multiple inlet connectors. The inlet rubber water-stop curtain is located in the middle part of the inlet flange and the inlet water-stop baffle, and is clamped and fixed by the inlet flange and the inlet water-stop baffle.

[0009] Preferably, the outer wall of the inlet of the outer sleeve is provided with an annular flange, and the inlet limiting device is welded to the outside of the flange.

[0010] Preferably, the inlet limiting device is respectively located directly above the inlet of the outer sleeve and on the corresponding sides in the horizontal direction.

[0011] Each of the inlet limiting devices includes: a first L-shaped limiting device, a first nylon roller, and a first connector, wherein the first nylon roller is disposed facing the outer wall of the inner through-pipe 1; the first L-shaped limiting device is formed by vertically welding two first H-shaped steels; the first nylon roller is connected to one of the first H-shaped steels through the first connector; the other first H-shaped steel is welded to the flange of the outer tube opening.

[0012] Preferably, a guide rail is also provided outside the inlet of the outer tube to support the inner tube.

[0013] Preferably, the outlet waterstop wall is located at the outlet of the outer sleeve pipe, and is constructed by stacking from the bottom of the inner wall of the outlet pipe upwards, with its horizontal height being higher than the predetermined water level line; the inner pipe end waterstop wall is set at the end of the first section of the inner pipe, and is constructed by stacking from the bottom of the inner wall of the end of the inner pipe upwards, with its horizontal height being higher than the predetermined water level line.

[0014] Preferably, the outlet water-stopping device includes: an outlet flange, an outlet rubber water-stopping curtain, an outlet water-stopping baffle, and multiple outlet connectors.

[0015] The outlet flange is an annular structure located inside the outlet waterstop wall, with an L-shaped cross-section. Its L-shaped longitudinal beam is installed on the inner wall of the outlet of the outer sleeve, and the L-shaped transverse beam is connected to the outlet waterstop baffle through multiple outlet connectors. The outlet rubber waterstop curtain is located in the middle part of the outlet flange and the outlet waterstop baffle, and is clamped and fixed by the outlet flange and the outlet waterstop baffle.

[0016] Preferably, the limiting rollers are installed on the inner wall of the outer sleeve, and each limiting roller includes: a second H-beam, a support plate, a fastener, a second nylon roller, and a second connector, with the second nylon roller facing the outer wall of the inner tube.

[0017] The second nylon roller is connected to the upper part of the second H-beam via a second connector; the lower part of the second H-beam is welded to the support plate; the support plate has fixing holes, and the support plate can be fixed to the inner wall of the outer sleeve by fasteners.

[0018] Preferably, the anti-collision roller at the end of the inner tube includes: a third H-beam, a third nylon roller, and a third connector, and the third nylon roller is disposed facing the inner wall of the outer tube.

[0019] The third nylon roller is connected to the upper part of the third H-beam via a third connector; the lower part of the third H-beam is welded to the outer wall of the end of the inner tube.

[0020] Preferably, the limiting rollers are symmetrically installed below the horizontal center line of the outer tube, forming a certain angle with the horizontal center line of the outer tube; the anti-collision rollers at the end of the inner tube are installed above the horizontal center line of the inner tube, forming a certain angle with the horizontal center line of the inner tube.

[0021] In summary, compared with the prior art, the buoyancy-based pipe-laying construction method provided by the present invention has at least the following beneficial effects:

[0022] (1) The present invention uses water as a carrier between the outer casing and the inner pipe, which greatly increases the bearing capacity and damage resistance of the carrier between the casings, reduces the friction of the inner pipe, improves construction efficiency, and shortens the overall construction cycle.

[0023] (2) The present invention has an inlet water-stopping device and an outlet water-stopping device at both ends of the outer tube, and both use rubber water-stopping curtains to seal the water source, which has good airtightness and can effectively prevent water from leaking out.

[0024] (3) This invention effectively solves the problems of insufficient strength of roller structure, poor durability and easy damage to the outer anti-corrosion layer of pipeline in traditional roller launching method, pipe outer wall caster installation method and pulley group propulsion method. It is especially suitable for internal pipe construction with large diameter, long distance and high requirements for finished product protection, and has good economy and implementation effect. Attached Figure Description

[0025] Figure 1 is a flowchart of the buoyancy tube insertion process according to an embodiment of the present invention;

[0026] Figure 2 is a schematic longitudinal section of the buoyancy tube provided in an embodiment of the present invention;

[0027] Figure 3 is a schematic cross-sectional view of the buoyancy pipe inlet provided in an embodiment of the present invention;

[0028] Figure 4 is a cross-sectional schematic diagram of the buoyancy-driven tube-piercing jacking process provided in an embodiment of the present invention;

[0029] Figure 5 is a schematic cross-sectional view of the buoyancy tube outlet provided in an embodiment of the present invention;

[0030] Figure 6 is a schematic diagram of a buoyancy-driven pipe-through-hole water-stopping device provided in an embodiment of the present invention;

[0031] Figure 7 is a schematic diagram of a buoyancy-driven pipe-through-hole water-stopping device provided in an embodiment of the present invention;

[0032] Figure 8 is a front view of a buoyancy-supported pipe-through-hole limiting roller provided in an embodiment of the present invention;

[0033] Figure 9 is a side view of the buoyancy pipe inlet limiting roller provided in an embodiment of the present invention;

[0034] Figure 10 is a front view of the anti-collision roller at the end of the buoyancy tube sleeve provided in an embodiment of the present invention;

[0035] Figure 11 is a side view of the anti-collision roller at the end of the buoyancy tube sleeve provided in an embodiment of the present invention;

[0036] Figure 12 is a top view of a buoyancy-guided inner limiting roller provided in an embodiment of the present invention;

[0037] Figure 13 is a front view of a buoyancy-guided inner limiting roller provided in an embodiment of the present invention;

[0038] Figure 14 is a side view of the buoyancy-through-tube inner limiting roller provided in an embodiment of the present invention;

[0039] Figure 15 is a reference diagram for buoyancy calculation through a tube according to an embodiment of the present invention.

[0040] Figure label:

[0041] Inner tube 1

[0042] Outer tube 2

[0043] Outer pipe opening flange 3

[0044] 4-way water-stopping device at the tunnel entrance

[0045] Entrance limiting device 5

[0046] Water-stopping device at the outlet 6

[0047] Internal pipe end waterstop wall 7

[0048] Waterstop wall at the outlet 8

[0049] 10 precast concrete spacers

[0050] Pre-determined water level 11

[0051] Limit roller 12

[0052] 13 anti-collision rollers at the end of the inner tube

[0053] 14-inch flange at the entrance

[0054] 15 rubber waterstop curtains at the entrance of the tunnel

[0055] 16 Water-stop baffles at the entrance of the tunnel

[0056] Entrance connector 17

[0057] 18-inch flange at the outlet

[0058] 19 rubber water-stop curtains at the outlet

[0059] 20 water-stop baffles at the outlet

[0060] Outlet connector 21

[0061] First H-beam 22

[0062] First Nylon Roller 23

[0063] First connector 24

[0064] Second H-beam 25

[0065] Support plate 26

[0066] Second nylon roller 27

[0067] Second connector 28

[0068] Fastener 29

[0069] Third H-beam 30

[0070] Third Nylon Roller 31

[0071] Third connector 32

[0072] Guide rail 33 Detailed Implementation

[0073] The present invention will be further described below with reference to Figures 1-15, by detailing a preferred embodiment.

[0074] It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions. They are only used to facilitate and clarify the purpose of illustrating the embodiments of the present invention, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationship, or adjustments to the size should still fall within the scope of the technical content disclosed in the present invention, provided that they do not affect the effects and objectives that the present invention can produce.

[0075] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only the expressly listed elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0076] As shown in Figures 1, 2, and 4, this invention provides a buoyancy-based pipe-insertion construction method, which utilizes buoyancy to insert the inner pipe 1 into the middle portion of the outer pipe 2, specifically including the following steps:

[0077] S1. Install an inlet water-stopping device 4 and an inlet limiting device 5 on one end of the outer sleeve 2 that serves as the inlet, and install an outlet water-stopping device 6 and an outlet water-stopping wall 8 on the other end of the outer sleeve 2 that serves as the outlet.

[0078] S2. Precast concrete pads 10 are evenly spaced along the axial direction at the bottom of the cavity inside the outer tube 2, and limiting rollers 12 are installed on the inner wall of the outer tube 2 (as shown in Figure 4).

[0079] S3. Using the power system, push the end of the first section of the inner pipe 1 into the inlet water-stopping device 4 a first predetermined distance. Then, construct an inner pipe end water-stopping wall 7 at the end of the inner pipe 1, and install an inner pipe end anti-collision roller 13 at the end of the inner pipe 1. It should be noted that in this embodiment, the inner pipe 1 is composed of multiple tubular structures, rather than a long, continuous pipe. Using multiple relatively short pipe sections facilitates the pushing of the inner pipe 1, making operation easier and improving efficiency. In this embodiment, the first predetermined distance is preferably 0.5m.

[0080] S4. Water is injected between the outer sleeve 2 and the inner tube 1. After reaching the predetermined water level 11, the inner tube 1 continues to be connected and advanced normally. It should be noted that the predetermined water level 11 needs to be calculated in advance based on the buoyancy of the inner tube 1. Due to factors such as the advancement of the inner tube 1, leakage of the outer sleeve 2, and water evaporation, the water level in the outer sleeve 2 will change continuously. Therefore, it is necessary to perform pumping and drainage operations in real time and monitor the water level in real time to ensure that the water level is always at the predetermined water level 11.

[0081] S5. When the inner tube 1 is advanced to the second predetermined distance in front of the water-stopping device 6 at the exit, the advancement is paused, the anti-collision roller 13 at the end of the inner tube is removed, and the advancement continues; in this embodiment, the second predetermined distance is preferably 1m;

[0082] S6. After the inner tube 1 pushes out of the opening water-stopping device 6, stop the advancement, drain the water source between the opening water-stopping device 6 and the outlet water-stopping wall 8, and remove the outlet water-stopping wall 8.

[0083] S7. Continue to push the inner tube 1 to the outside of the outer tube 2, and complete the pushing of the inner tube 1;

[0084] S8. Drain the water source between the inner pipe 1 and the outer pipe 2, so that the inner pipe 1 falls vertically onto the precast concrete pad 10.

[0085] S9. Remove the waterstop wall 7 at the end of the inner pipe to complete the buoyancy pipe construction.

[0086] In this embodiment, the outer casing 2 is a reinforced concrete jacking pipe with an inner diameter of 4000mm; the inner pipe 1 is a steel pipe with an outer diameter of 3600mm and a wall thickness of 30mm; before carrying out the buoyancy pipe installation, the following preparatory work needs to be done:

[0087] As shown in Figures 2 and 4, the entrance water-stopping device 4 and the entrance limiting device 5 need to be installed at the entrance; the exit water-stopping device 6 and the exit water-stopping wall 8 need to be installed at the exit; the precast concrete pads 10 are evenly spaced below the cavity inside the outer sleeve 2, and limiting rollers 12 are installed on the corresponding sides of the inner wall of the outer sleeve 2.

[0088] Furthermore, as shown in Figures 3 and 6, the inlet water-stopping device 4 includes: an inlet flange 14, an inlet rubber water-stopping curtain 15, an inlet water-stopping baffle 16, and multiple inlet connectors 17. The inlet flange 14 has an annular structure with a T-shaped cross-section. Its T-shaped longitudinal beam is installed on the inner wall of the inlet of the outer sleeve 2, and the T-shaped transverse beam is connected to the inlet water-stopping baffle 16 through multiple inlet connectors 17. The inlet rubber water-stopping curtain 15 is located in the middle part of the inlet flange 14 and the inlet water-stopping baffle 16, and is clamped and fixed by the inlet flange 14 and the inlet water-stopping baffle 16. In this embodiment, both the inlet water-stop baffle 16 and the inlet rubber water-stop curtain 15 are annular structures. Multiple inlet connectors 17 are distributed around the inlet flange 14, fixing the inlet water-stop baffle 16 to the inlet flange 14. Furthermore, the length of the inlet rubber water-stop curtain 15 is greater than the lengths of both the inlet flange 14 and the inlet water-stop baffle 16, ensuring that the inner pipe 1 can fit tightly against the inlet rubber water-stop curtain 15 during jacking, preventing water leakage. In this embodiment, the inlet connectors 17 are bolt assemblies, and the inlet flange 14 is a pipe flange.

[0089] Further, as shown in Figures 3, 8, and 9, the outer wall of the inlet of the outer sleeve 2 is annularly fitted with an outer sleeve inlet flange 3, and the inlet limiting device 5 is welded to the outside of the outer sleeve inlet flange 3. Specifically, three inlet limiting devices 5 are arranged, respectively positioned directly above the inlet of the outer sleeve and on corresponding sides in the horizontal direction. Each inlet limiting device 5 includes: a first L-shaped limiting device, a first nylon roller 23, and a first connecting piece 24. The first nylon roller 23 is positioned facing the outer wall of the inner tube 1. The first L-shaped limiting device is formed by vertically welding two first H-beams 22. Then, the lower rib of one of the first H-beams 22 is cut to form a groove for installing the first nylon roller 23, and the first nylon roller 23 is connected to the first H-beam 22 by the first connecting piece 24. Finally, the other first H-beam 22 is welded to the outer sleeve inlet flange 3, thereby obtaining the inlet limiting device 5. In this embodiment, the first connector 24 is a bolt assembly, and the first nylon roller 23 is spaced 20-30mm from the outer wall of the inner tube 1 to ensure that the inner tube 1 will not rub excessively due to the small distance between the first nylon roller 23 and the tube wall during jacking. This can effectively protect the outer wall of the inner tube 1, extend its service life, and reduce maintenance costs during construction.

[0090] Furthermore, as shown in Figures 2 and 3, a guide rail 33 is also provided outside the inlet of the outer sleeve 2 to support the inner tube 1 and guide the jacking direction of the inner tube 1.

[0091] It is understood that the jacking principle of the inner tube 1 of the present invention is as follows: First, the first section of the inner tube 1 is jacked into the guide rail 33. After the first section of the inner tube 1 is jacked into the guide rail 33, a connecting pipe operation is performed to weld the second section of the inner tube to the first section of the inner tube 1. Then, the jacking continues and the third section of the inner tube is welded. This process is repeated until the entire jacking process is completed.

[0092] In addition, the inlet limiting device 5, combined with the guide rail 33 that supports the inner pipe 1 at the bottom, can play a good limiting and fixing role, so that the inner pipe 1 that has been pushed in will not be displaced by water buoyancy when the pipe is connected, thus improving the efficiency of pipe connection construction.

[0093] Furthermore, as shown in Figures 2 and 5, the outlet waterstop wall 8 is located at the outlet of the outer sleeve 2, and is constructed by stacking the inner wall of the outlet pipe upwards, with its height higher than the predetermined water level line 11. In this embodiment, the outlet waterstop wall 8 is constructed of solid concrete bricks and MU10 cement mortar, with a wall thickness of 400mm and a top height 300mm to 500mm higher than the predetermined water level. The two sides of the wall are plastered with cement mortar to prevent water leakage between the sleeves.

[0094] Furthermore, as shown in Figures 2, 5, and 7, the outlet water-stopping device 6 is installed on the inner side of the outlet water-stopping wall 8, and there is a third predetermined distance between it and the inner wall of the outlet water-stopping wall 8. In this embodiment, the third predetermined distance is set to 1m.

[0095] Furthermore, the outlet water-stopping device 6 includes: an outlet flange 18, an outlet rubber water-stopping curtain 19, an outlet water-stopping baffle 20, and multiple outlet connectors 21. The outlet flange 18 is an annular structure located inside the outlet water-stopping wall 8, with an L-shaped cross-section. Its L-shaped longitudinal beam is installed on the inner wall of the outlet of the outer sleeve 2, and the L-shaped transverse beam is connected to the outlet water-stopping baffle 20 through multiple outlet connectors 21. The outlet rubber water-stopping curtain 19 is located in the middle part of the outlet flange 18 and the outlet water-stopping baffle 20, and is clamped and fixed by the outlet flange 18 and the outlet water-stopping baffle 20. In this embodiment, both the outlet water-stop baffle 20 and the outlet rubber water-stop curtain 19 are annular structures. Multiple outlet connectors 21 are distributed around the outlet flange 18, fixing the outlet water-stop baffle 20 to the outlet flange 18. Furthermore, the length of the outlet rubber water-stop curtain 19 is greater than the lengths of both the outlet flange 18 and the outlet water-stop baffle 20, ensuring that the inner pipe 1 can tightly fit against the outlet rubber water-stop curtain 19 as it continues to advance, preventing water leakage. In this embodiment, the outlet connectors 21 are bolt assemblies, and the outlet flange 18 is a pipe flange.

[0096] Furthermore, as shown in Figures 2 and 4, the height of the precast concrete pad 10 is the designed gap height between the inner tube 1 and the outer tube 2, and is designed according to requirements. These pads are evenly spaced at the bottom of the cavity inside the outer tube 2. In this embodiment, the precast concrete pad 10 is made of C30 concrete, with a height equal to the designed gap height between the inner tube 1 and the outer tube 2, a width of 1m, a length of 0.4m, and is arranged at intervals of 8-10m.

[0097] Further, as shown in Figures 4, 12, 13, and 14, the limiting roller 12 is manufactured from a second H-beam 25, a support plate 26, a fastener 29, a second nylon roller 27, and a second connector 28. The second nylon roller 27 is positioned facing the outer wall of the inner tube 1. Specifically, firstly, the upper rib of the second H-beam 25 is cut to form a groove for installing the second nylon roller 27, and the second nylon roller 27 is connected to the second H-beam 25 via the second connector 28. Secondly, the lower part of the second H-beam 25 is welded to the support plate 26. Finally, holes are made at the four corners of the support plate 26 to install the fastener 29, and the support plate 26 is fixed to the inner wall of the outer tube 2 via the fastener 29 to achieve the function of limiting and fixing. In this embodiment, the fastener 29 is an expansion bolt, and the second connector 28 is a bolt assembly. In this invention, the limiting rollers serve to fix the pipe position, limit the range of pipe movement, and guide the advancement, making this invention applicable to some internal pipe construction with large curvature radii.

[0098] Furthermore, as shown in Figures 4, 10, and 11, after the end of the first section of the inner tube 1 is pushed into the inlet water-stopping device 4, the inner tube end anti-collision roller 13 is installed. The inner tube end anti-collision roller 13 is manufactured from a third H-beam 30, a third nylon roller 31, and a third connector 32, with the third nylon roller 31 facing the inner wall of the outer tube 2. Specifically, firstly, the upper rib of the third H-beam 30 is cut to form a groove for installing the third nylon roller 31, and the third nylon roller 31 is connected to the third H-beam 30 via the third connector 32; then, the lower part of the third H-beam 30 is welded to the outer wall of the end of the inner tube 1, thereby providing anti-collision protection and preventing the inner tube 1 from being damaged by impact during the jacking process, or even damaging the outer anti-corrosion coating of the inner tube 1.

[0099] Furthermore, as shown in Figure 4, in this embodiment, the limiting rollers 12 are arranged in groups of two every 20m to 30m, symmetrically installed below the horizontal center line of the outer sleeve 2, forming a 10° angle with the horizontal center line of the outer sleeve 2; the inner pipe end anti-collision rollers 13 are installed on both sides of the outer wall of the end of the inner pipe 1, comprising two in total, respectively installed above the horizontal center line of the inner pipe 1, forming a 10° angle with the horizontal center line of the inner pipe 1. It can be understood that the limiting rollers 12 and the inner pipe end anti-collision rollers 13 are arranged alternately. In addition, the position of the limiting rollers 12 under this design is higher than the predetermined water level line 11, making it easier to observe the use of the limiting rollers 12 during pipe insertion; the inner pipe end anti-collision rollers 13 under this design can provide good anti-collision while avoiding the limiting rollers 12.

[0100] Furthermore, as shown in Figure 2, after the end of the first section of the inner pipe 1 is pushed into the inlet water-stopping device 4, an inner pipe end water-stopping wall 7 is constructed at the end of the inner pipe 1. This inner pipe end water-stopping wall 7 is built from the bottom of the inner wall of the end of the inner pipe 1 upwards, stacked together, and its height is higher than the predetermined water level line 11. In this embodiment, the inner pipe end water-stopping wall 7 is constructed of solid concrete bricks and MU10 cement mortar, with a wall thickness of 400mm. The top of the wall is 300mm to 500mm higher than the predetermined water level, and both sides of the wall are plastered with cement mortar, which can prevent water from flowing between the outer casing 2 and the inner pipe 1 into the inner pipe 1, effectively isolating the water flow.

[0101] Furthermore, as shown in Figure 2, water is injected into the outer casing 2 from the receiving well to raise the water level to the height of the predetermined water level line 11. The height of the predetermined water level line 11 is the water surface height when the buoyancy of the water causes the inner casing 1 to float above the concrete pad block 10.

[0102] As shown in Figure 15, the predetermined water level 11 is calculated using a preferred embodiment. In this embodiment, the outer casing 2 is a reinforced concrete pipe with an inner diameter of 4000 mm, the inner casing 1 has an outer diameter of 3260 mm, a wall thickness of 30 mm, and a steel density of 7.85 t / m³. Therefore, the weight of each meter of pipe is 2.3885 t. The height of the predetermined water level 11 is calculated as follows:

[0103] According to the buoyancy calculation formula: F 浮 =G 排 ;

[0104] It can be seen that when the inner pipe 1 with an outer diameter of 3260mm and a wall thickness of 34mm floats on the water surface, the volume of water that needs to be displaced per meter of pipe is 2.3885m³.

[0105] That is, the cross-sectional area of ​​the outer wall of the pipe submerged in water is S = 2.3885㎡;

[0106] Introducing the formula for the area of ​​a segment: S = 0.5r 2 (θ-sinθ);

[0107] Substituting the value 2.3885, we get 0.5 × 1.63. 2 (θ-sinθ);

[0108] Using Newton's iterative method, we can solve for θ (central angle) = 2.44195 (radians).

[0109] The distance from the predetermined water level line 11 to the center line of the inner pipe 1 is: h = r•cos(θ / 2)

[0110] The calculated value is h = 0.559 m;

[0111] During the buoyancy-assisted pipe insertion process, control the distance h between the inner pipe 1 and the precast concrete pad 10. ′ = 50mm;

[0112] The height of the predetermined water level line 11 is: H = (R + h) ′ -h;

[0113] Substituting the values, we get H = 1.491m.

[0114] After the water source is injected to the predetermined water level line 11 at 1.491m, the conventional pipe connection and advancement stage begins. However, due to factors such as water evaporation, minor leakage, and the increase in the jacking length and volume of the inner pipe 1, the water level inside the outer pipe 2 will change. Therefore, it is necessary to monitor the water level inside the outer pipe 2 during the conventional pipe connection and advancement stage, and adjust the water level height inside the pipe through measures such as pumping and drainage to keep it within the predetermined water level range of 1.491m ± 25mm. This will prevent collisions between the inner pipe 1 and the outer pipe 2 or the precast concrete pad 10 below due to excessively high or low water levels, or tearing of the rubber waterstop curtain 15 at the entrance and the rubber waterstop curtain 19 at the exit.

[0115] Furthermore, in this embodiment, the buoyancy-driven propulsion process also includes the following:

[0116] Specifically, as shown in Figures 2 and 4, the inner tube 1 stops advancing when it reaches a certain distance before the exit water-stopping device 6. In this embodiment, this distance is 50cm. At this point, the anti-collision roller 13 at the end of the inner tube is removed to prevent it from colliding with the exit water-stopping device 6. At this time, the inner tube 1 is close to the exit water-stopping device 6, and the limiting roller 12 inside the outer tube 2 can guide its continued advancement, allowing the end of the inner tube 1 to pass through the exit water-stopping device 6.

[0117] Specifically, the inner tube 1 stops advancing 50cm after passing through the outlet water-stopping device 6. At this time, the inner tube 1 is tightly fitted to the outlet rubber water-stopping curtain 19, and the water source between the outer tube 2 and the inner tube 1 changes from being blocked by the inlet water-stopping device 4 and the outlet water-stopping wall 8 to being blocked by the inlet water-stopping device 4 and the outlet water-stopping device 6. At this time, the water source between the outlet water-stopping device 6 and the outlet water-stopping wall 8 is drained, and the outlet water-stopping wall 8 is removed to allow the inner tube 1 to exit the hole.

[0118] Specifically, the advancement of the inner pipe 1 ends when the end of the inner pipe 1 protrudes beyond the end of the outer pipe 2 by a distance of 0.5m. At this point, the water source between the outer pipe 2 and the inner pipe 1 can be drained by adjusting the outlet water-stopping baffle 20 of the outlet water-stopping device 6 and loosening the outlet rubber water-stopping curtain 19. Then, the inner pipe 1 will fall vertically onto the precast concrete pad 10 under the limiting device 12 within the outer pipe 2, reaching the designed height. Finally, the water-stopping wall 7 at the end of the inner pipe is removed, completing the advancement of the inner pipe 1.

[0119] In summary, this invention provides a buoyancy-based pipe-through-the-tube construction method for casing pipes. Using a water source as a carrier between the outer casing and the inner pipe significantly increases the load-bearing capacity and damage resistance of the carrier, reduces the friction during the inner pipe's advancement, improves construction efficiency, and shortens the overall construction cycle. This invention features inlet and outlet water-stop devices at both ends of the outer casing, both using rubber water-stop curtains to seal the water source, providing excellent airtightness and preventing water leakage. Limiting rollers are installed at the inlet, the inner wall of the outer casing, and the end of the inner pipe. These limiting rollers fix the pipe position and guide its advancement, making this invention applicable to inner pipe construction with large radii of curvature. Furthermore, these limiting rollers are made of nylon, and all devices are connected to the inner pipe via flexible connections, providing excellent protection for the inner pipe's anti-corrosion coating. In addition, this invention effectively solves the problems of insufficient strength of the roller structure, poor durability, and easy damage to the outer anti-corrosion layer of the pipeline in traditional roller launching method, pipe external wall caster installation method, and pulley group propulsion method. It is especially suitable for internal pipe construction with large diameter, long distance and high requirements for finished product protection, and has good economy and implementation effect.

[0120] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A buoyancy pipe-through method of construction, using buoyancy to pass a through-pipe through an intermediate section of an outer casing, characterised in that, Specifically, it includes the following steps: S1. Install an inlet water-stop device and an inlet limiting device on one end of the outer sleeve as the inlet, and install an outlet water-stop device and an outlet water-stop wall on the other end of the outer sleeve as the outlet. S2. Precast concrete pads are evenly spaced along the axial direction at the bottom of the cavity inside the outer tube, and limiting rollers are installed on the inner wall of the outer tube. S3. Using the power system, push the end of the first section of the inner pipe into the inlet water-stopping device by a first set distance, then make an inner pipe end water-stopping wall at the end of the inner pipe, and install an inner pipe end anti-collision roller at the end of the inner pipe. S4. Water is injected between the outer tube and the inner tube until the predetermined water level is reached. Then the inner tube continues to connect and advance normally. S5. When the inner tube is advanced to the second predetermined distance in front of the water-stopping device at the exit, the advancement is paused. After the anti-collision roller at the end of the inner tube is removed, the advancement continues. S6. After the inner tube pushes out of the hole-stopping device, stop the advancement, drain the water source between the hole-stopping device and the outlet-stopping wall, and remove the outlet-stopping wall. S7. Continue pushing the inner tube to the outlet of the outer tube, completing the pushing of the inner tube; S8. Drain the water source between the inner pipe and the outer pipe, so that the inner pipe falls vertically onto the precast concrete pad block. S9. Remove the waterstop wall at the end of the inner pipe to complete the buoyancy pipe installation.

2. The buoyancy pipe ramming construction method according to claim 1, wherein The inlet water-stopping device includes: an inlet flange, an inlet rubber water-stopping curtain, an inlet water-stopping baffle, and multiple inlet connectors; The inlet flange is an annular structure with a T-shaped cross-section. Its T-shaped longitudinal beam is installed on the inner wall of the inlet of the outer sleeve, and the T-shaped transverse beam is connected to the inlet waterstop baffle through multiple inlet connectors. The rubber water-stop curtain at the entrance is located in the middle part of the entrance flange and the entrance water-stop baffle, and is clamped and fixed by the entrance flange and the entrance water-stop baffle.

3. The method of buoyancy pipe installation according to claim 1, wherein The outer wall of the inlet of the outer sleeve is fitted with an outer sleeve inlet flange in a ring shape, and the inlet limiting device is welded to the outside of the outer sleeve inlet flange.

4. The buoyancy pipe ramming method as claimed in claim 3, wherein The inlet limiting devices are respectively located directly above the inlet of the outer sleeve and on the corresponding sides in the horizontal direction; Each of the inlet limiting devices includes: a first L-shaped limiting device, a first nylon roller, and a first connector, wherein the first nylon roller is disposed facing the outer wall of the inner through-pipe 1; the first L-shaped limiting device is formed by vertically welding two first H-shaped steels; the first nylon roller is connected to one of the first H-shaped steels through the first connector; the other first H-shaped steel is welded to the flange of the outer tube opening.

5. The method of buoyancy pipe installation according to claim 1, wherein The outer casing is also equipped with a guide rail outside the inlet to support the inner casing.

6. The method of buoyancy pipe installation according to claim 1, wherein The outlet waterstop wall is located at the outlet of the outer sleeve. It is built up from the bottom of the inner wall of the outlet pipe and stacked upwards. Its horizontal height is higher than the predetermined water level line. The waterstop wall at the end of the inner pipe is set at the end of the first section of the inner pipe. It is built up from the bottom of the inner wall of the end of the inner pipe and stacked, and its horizontal height is higher than the predetermined water level line.

7. The method of buoyancy pipe installation of claim 1 wherein, The outlet water-stopping device includes: an outlet flange, an outlet rubber water-stopping curtain, an outlet water-stopping baffle, and multiple outlet connectors; wherein, the outlet flange is a ring structure, located on the inner side of the outlet water-stopping wall, with an L-shaped cross section, and its L-shaped longitudinal beam is installed on the inner wall of the outlet of the outer sleeve, and the L-shaped transverse beam is connected to the outlet water-stopping baffle through multiple outlet connectors; The rubber water-stop curtain at the outlet is located in the middle part of the outlet flange and the outlet water-stop baffle, and is clamped and fixed by the outlet flange and the outlet water-stop baffle.

8. The method of buoyancy pipe installation of claim 1 wherein, The limiting rollers are installed on the inner wall of the outer sleeve. Each limiting roller includes: a second H-beam, a support plate, a fastener, a second nylon roller, and a second connector, with the second nylon roller facing the outer wall of the inner tube. The second nylon roller is connected to the upper part of the second H-beam via a second connector; the lower part of the second H-beam is welded to the support plate; the support plate has fixing holes, and the support plate can be fixed to the inner wall of the outer sleeve by fasteners.

9. The buoyancy pipe ramming method as claimed in claim 8, wherein The inner tube end anti-collision roller includes: a third H-beam, a third nylon roller and a third connector, and the third nylon roller is arranged facing the inner wall of the outer tube; The third nylon roller is connected to the upper part of the third H-beam via a third connector; the lower part of the third H-beam is welded to the outer wall of the end of the inner tube.

10. The buoyancy pipe ramming method as claimed in claim 9, wherein The limiting rollers are symmetrically installed below the horizontal center line of the outer tube, forming a certain angle with the horizontal center line of the outer tube; The anti-collision roller at the end of the inner tube is installed above the horizontal center line of the inner tube, forming a certain angle with the horizontal center line of the inner tube.

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