Trenchless pipeline obstacle removal method
By setting up working wells at both ends of the scrapped steel pipe, using a traction machine, a pipe milling machine, and a pipe puller, combined with the injection of friction reducers and bentonite, the problem of high construction difficulty in cleaning ultra-long and ultra-deep pipelines under trenchless conditions was solved, achieving efficient and safe pipeline clearing.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SHANGHAI MECHANIZED CONSTR GRP
- Filing Date
- 2026-01-23
- Publication Date
- 2026-07-30
AI Technical Summary
Existing technologies are difficult to implement flexibly under trenchless conditions, are not applicable to different soil geological conditions, and are difficult to efficiently clean ultra-long and ultra-deep pipelines, resulting in high construction difficulty and long construction period.
A trenchless pipeline clearing method is adopted, which involves setting up working wells at both ends of the scrapped steel pipe, using a traction machine, a pipe milling machine, and a pipe puller, combined with the injection of friction reducing agent and bentonite, to carry out internal purging, external cleaning, and segmented pullback.
It enables trenchless operation, applicable to different soil geological conditions, shortens the cleaning period, reduces construction difficulty, ensures smooth clearance of various types of pipelines, and improves cleaning efficiency and safety.
Smart Images
Figure CN2026074533_30072026_PF_FP_ABST
Abstract
Description
Trenchless pipeline clearing methods
[0001] This application claims priority to Chinese Patent Application No. 202510114607.0, filed with the Chinese Patent Office on January 24, 2025, the entire contents of which are incorporated herein by reference. Technical Field
[0002] This application relates to the field of underground engineering technology, for example to a trenchless pipeline clearing method. Background Technology
[0003] Currently, traditional methods for clearing underground pipelines often employ open-cut excavation or conventional towing methods. However, open-cut excavation is difficult to implement when there are other pipelines above or when the pipeline network within the construction area is complex. Furthermore, pipelines buried deep in soil for extended periods exhibit high compaction, significant friction due to tight grouting, and are prone to breakage due to poor-quality joints, making conventional towing methods unsuitable for clearing. Clearing extremely long and deep pipelines presents even greater challenges. Therefore, finding a non-excavation method applicable to different soil conditions, flexibly implementing the method, shortening the clearing period, and reducing construction difficulty to ensure successful clearing of various types of pipelines is a problem that researchers in this field need to solve. Summary of the Invention
[0004] This application provides a trenchless pipeline clearing method that is applicable to different soil geological conditions without excavation, can be flexibly implemented, shortens the clearing period, reduces construction difficulty, and ensures the smooth clearing of various types of pipelines.
[0005] This application provides a trenchless pipeline clearing method, including:
[0006] A working well is set up at each end of the scrapped steel pipe, and a traction machine is set up next to one of the working wells;
[0007] Inject friction-reducing agent at intervals on the surface of the formation up to the discarded steel pipe;
[0008] Install a temporary valve at the first end of the scrapped steel pipe, purge the inside of the scrapped steel pipe, and remove the temporary valve after purging.
[0009] Connect the milling sleeve to the traction machine, and connect the milling sleeve to the scrap steel pipe through the connecting ring. Clean the outside of the scrap steel pipe, and remove the milling sleeve after cleaning.
[0010] Connect the pipe puller to the traction machine, and connect the scrap steel pipe to the pipe puller to pull back the scrap steel pipe in sections.
[0011] In some embodiments, injecting a friction-reducing agent at intervals on the formation surface to the scrapped steel pipe includes:
[0012] Multiple grouting holes are drilled at intervals and through the surface of the formation.
[0013] An observation hole is installed between two adjacent grouting holes;
[0014] The friction-reducing agent is injected into the scrapped steel pipe through the grouting hole until grout appears in the observation hole, at which point the injection is stopped.
[0015] In some embodiments, the spacing between two adjacent grouting holes is set to 10 meters.
[0016] In some embodiments, the amount of friction reducer injected ranges from 500 to 1000 kg.
[0017] In some embodiments, a temporary valve is installed at the first end of the scrap steel pipe, the interior of the scrap steel pipe is purged, and the temporary valve is removed after purging, including:
[0018] Select an open area that allows the discharge of waste and debris as the purge outlet;
[0019] Install a temporary valve at the first end of the scrapped steel pipe, and place the temporary valve near the purge port;
[0020] Use a compressed air machine to blow out the inside of the scrap steel pipe. When the pressure inside the scrap steel pipe reaches the preset pressure during blowing, quickly open the temporary valve to discharge the dirt and debris.
[0021] After completing the internal purging of the scrapped steel pipe, remove the temporary valve.
[0022] In some embodiments, the outlet centerline of the temporary valve is installed 30 degrees upwards, offset from the vertical.
[0023] In some embodiments, the preset pressure is set to 1.5 MPa.
[0024] In some embodiments, the milling sleeve includes a tube body and a milling head. The connecting ring is sleeved on the outside of the scrap steel pipe and the tube body, and there is a gap between the connecting ring and both the scrap steel pipe and the tube body. During the cleaning process, the connecting ring can move synchronously with the tube body on the outside of the scrap steel pipe. The milling head is configured to clean the outside of the scrap steel pipe.
[0025] In some embodiments, when the milling tube performs external cleaning on the scrap steel pipe, bentonite is injected into the outside of the scrap steel pipe to reinforce and lubricate it.
[0026] In some embodiments, the pipe puller is connected to the traction machine, and the scrap steel pipe is connected to the pipe puller to perform segmented back pulling of the scrap steel pipe, including:
[0027] The first end of the pipe puller is connected to the traction machine, and the second end of the pipe puller is connected to the first end of the scrap steel pipe. The second end of the scrap steel pipe is operated in conjunction with the pipe puller using a tamping hammer.
[0028] The scrapped steel pipes are pulled back in 10-meter segments. After each segment is pulled out, the pulled-out segment is cut off from the unpulled portion. Then, the pipe puller is reconnected to the unpulled portion for further pulling back.
[0029] After all the scrapped steel pipes have been pulled back, remove the pipe puller and fill the holes with cement grout. Attached Figure Description
[0030] Figure 1 is a flowchart of the trenchless pipeline clearing method according to an embodiment of this application;
[0031] Figure 2 is a schematic diagram of step S1 in the trenchless pipeline clearing method described in the embodiment of this application;
[0032] Figure 3 is a schematic diagram of step S4 of the trenchless pipeline clearing method according to an embodiment of this application;
[0033] Figure 4 is a partially enlarged schematic diagram of the connection between the milling sleeve and the scrapped steel pipe in the trenchless pipeline clearing method described in the embodiment of this application.
[0034] Figure 5 is a schematic diagram of step S5 of the trenchless pipeline clearing method described in the embodiment of this application.
[0035] In the picture:
[0036] 100. Waste steel pipe; 101. Hole; 200. Formation surface; 10. Working well; 20. Traction machine; 30. Milling sleeve; 31. Pipe body; 32. Milling head; 40. Connecting ring; 50. Pipe puller. Detailed Implementation
[0037] Embodiments of this application are described below, with examples of the embodiments shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application.
[0038] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the meaning of the above terms in this application as appropriate.
[0039] In the description of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or indicating that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or indicating that the first feature is at a lower horizontal level than the second feature.
[0040] The technical solution of this embodiment will be described below with reference to the accompanying drawings and specific implementation methods.
[0041] As shown in Figures 1-5, this embodiment provides a trenchless pipeline clearing method, including the following steps:
[0042] S1. A working well 10 is set at each end of the scrapped steel pipe 100, and a traction machine 20 is set next to one of the working wells 10;
[0043] S2. Inject friction-reducing agent at intervals on the surface of the formation up to 100 meters from the discarded steel pipe;
[0044] S3. Install a temporary valve at the first end of the scrap steel pipe 100, purge the inside of the scrap steel pipe 100, and remove the temporary valve after purging.
[0045] S4. Connect the milling sleeve 30 to the traction machine 20, and connect the milling sleeve 30 to the scrap steel pipe 100 through the connecting ring 40. Clean the outside of the scrap steel pipe 100. After cleaning, remove the milling sleeve 30.
[0046] S5. Connect the pipe puller 50 to the traction machine 20, and connect the scrap steel pipe 100 to the pipe puller 50 to pull back the scrap steel pipe 100 in sections.
[0047] For example, in this embodiment, two working wells 10 are used to facilitate the placement of subsequent milling and pipe-pulling equipment, and to facilitate the cleaning of exhaust gas inside the scrap steel pipe 100. Injecting a friction-reducing agent before internal and external cleaning can improve the subsequent pullback efficiency of the scrap steel pipe 100. In addition, by controlling the temporary valve to purge the inside of the scrap steel pipe 100 and using the milling tube 30 to clean the outside of the scrap steel pipe 100, it is possible to effectively avoid explosions caused by static electricity generated during dismantling, and to avoid interference with the pullback movement of the scrap steel pipe 100, thereby improving the pullback efficiency. Furthermore, by using the pipe puller 50 to pull back the scrap steel pipe 100 in sections, not only can a rapid pullback effect be achieved in a limited space, but it can also improve the clearance efficiency of long pipelines and reduce safety risks.
[0048] The process of the trenchless pipeline clearing method in this embodiment will be described below.
[0049] Referring to Figures 1-5, the trenchless pipeline clearing method in this embodiment includes:
[0050] S1. A working well 10 is set at each end of the scrapped steel pipe 100, and a traction machine 20 is set next to one of the working wells 10;
[0051] S2. Inject friction-reducing agent at intervals on the surface of the formation up to 100 meters from the discarded steel pipe;
[0052] S3. Install a temporary valve at the first end of the scrap steel pipe 100, purge the inside of the scrap steel pipe 100, and remove the temporary valve after purging.
[0053] S4. Connect the milling sleeve 30 to the traction machine 20, and connect the milling sleeve 30 to the scrap steel pipe 100 through the connecting ring 40. Clean the outside of the scrap steel pipe 100. After cleaning, remove the milling sleeve 30.
[0054] S5. Connect the pipe puller 50 to the traction machine 20, and connect the scrap steel pipe 100 to the pipe puller 50 to pull back the scrap steel pipe 100 in sections.
[0055] For example, in this embodiment, working wells 10 are respectively provided at both ends of the scrap steel pipe 100. The two working wells 10 ensure smooth placement of subsequent milling and pipe-pulling equipment and facilitate the removal of exhaust gas inside the scrap steel pipe 100. For example, in related technologies, well leakage often occurs during shallow soil drilling operations due to loose strata, i.e., mud leakage during drilling. If not effectively suppressed, a large amount of mud may directly enter the strata and flow through them, carrying away a large amount of stratum filling material, leading to a loss of stratum support and severe borehole collapse. Therefore, timely sealing is necessary. Referring to Figure 2, in this embodiment, a "two-high, one-appropriate" mud sealing scheme can be adopted during construction. The "two highs" refer to high viscosity and high soil content, and the "one appropriate" refers to an appropriate concentration of sealing material, which can promptly form a dense sealing layer on the well wall. For example, this type of mud can be used for sealing the well wall in the working well 10. After entering the formation, this type of mud can still effectively block the channels in the formation to prevent the mud from seeping into the formation and thus avoid the collapse caused by the mud flowing and hollowing out the formation. In this embodiment, the use of this type of mud for sealing can also ensure the stability of the subsequent cleaning of the scrapped steel pipe 100 and the smooth progress of the pipe pulling operation.
[0056] In some embodiments, step S2 includes:
[0057] S2.1. Drill multiple grouting holes at intervals and through the formation surface at a depth of 200 mm.
[0058] S2.2, An observation hole is set between two adjacent grouting holes;
[0059] S2.3 Inject the friction reducer into the scrapped steel pipe 100 through the grouting hole until grout comes out of the observation hole and stop injecting.
[0060] Optionally, in this embodiment, the spacing between two adjacent grouting holes is set to 10 meters (m), and the amount of friction-reducing agent injected ranges from 500 to 1000 kilograms (kg), thereby ensuring smooth pipe extraction and reducing friction between the scrapped steel pipe 100 and the surrounding soil. For example, in this embodiment, the friction-reducing agent can be the mud slurry from step S1, which is injected into the grouting holes to coat the outside of the scrapped steel pipe 100, reducing friction.
[0061] In some embodiments, step S3 includes:
[0062] S3.1 Select an open area where sewage and debris can be discharged as the purge outlet;
[0063] S3.2 Install a temporary valve at the first end of the scrapped steel pipe 100, and place the temporary valve near the purge port;
[0064] S3.3 Use a compressed air machine to purge the inside of the scrap steel pipe 100, and when the internal pressure of the scrap steel pipe 100 reaches the preset pressure during purging, quickly open the temporary valve to discharge dirt and debris;
[0065] S3.4 After completing the internal purging of the scrapped steel pipe 100, remove the temporary valve.
[0066] For example, in this embodiment, the outlet centerline of the temporary valve is installed upwards at a 30-degree angle off the vertical line, and the outlet of the temporary valve is higher than the top of the scrap steel pipe 100. This ensures thorough cleaning of the interior of the scrap steel pipe 100 and prevents debris from falling back. For example, the preset pressure is set to 1.5 MPa, but it can be set as needed in other embodiments. For example, in this embodiment, the purging port is located in an open area that allows the discharge of sewage and debris without threatening the safety of surrounding people and objects, thereby reducing operational risks and achieving environmental protection. For example, in this embodiment, a compressed air machine is used to provide dry, clean air to purge the interior of the scrap steel pipe 100, ensuring thorough cleaning of the interior of the scrap steel pipe 100, thereby improving dismantling efficiency, avoiding interference with subsequent pipe pulling and cutting operations, and ensuring the safety and smooth progress of the entire dismantling work, preventing static electricity from causing an explosion during the dismantling process.
[0067] Referring to Figures 3 and 4, in this embodiment, the milling sleeve 30 includes a tube body 31 and a milling head 32. Exemplarily, the first end of the tube body 31 can be connected to the traction machine 20, and the second end of the tube body 31 is connected to the milling head 32. A connecting ring 40 is sleeved on the outside of the scrap steel pipe 100 and the tube body 31, with gaps between the connecting ring 40 and both the scrap steel pipe 100 and the tube body 31. This allows the milling head 32 to move outside the scrap steel pipe 100 for cleaning under the drive of the traction machine 20 and the tube body 31. During this cleaning process, the connecting ring 40 can move synchronously with the tube body 31 outside the scrap steel pipe 100, ensuring that the milling sleeve 30 always moves outside the scrap steel pipe 100 and does not detach. For example, when the milling sleeve 30 cleans the exterior of the scrap steel pipe 100, it increases the gap between the outer side of the scrap steel pipe 100 and the soil, forming a hole 101. During cleaning, bentonite is simultaneously injected into the outer side of the scrap steel pipe 100, i.e., into the hole 101, thereby reinforcing the load-bearing soil around the scrap steel pipe 100 and lubricating the movement of the milling sleeve 30, improving cleaning efficiency. For example, in this embodiment, the bentonite can also be the slurry from step S1. Injecting slurry into the hole 101 reinforces and lubricates the inner wall of the hole 101, ensuring smooth movement of the milling sleeve 30.
[0068] In some embodiments, step S5 includes:
[0069] S5.1 Connect the first end of the pipe puller 50 to the traction machine 20, and connect the second end of the pipe puller 50 to the first end of the scrap steel pipe 100. The second end of the scrap steel pipe 100 is operated by the pipe puller 50 in conjunction with the tamping hammer.
[0070] S5.2. Pull back the scrap steel pipe 100 in 10m sections, and cut off the scrap steel pipe 100 that has been pulled out from the unpulled section after each section is pulled out. Then reconnect the pipe puller 50 to the unpulled section and pull it back.
[0071] S5.3 After all the scrapped steel pipes 100 have been pulled back, remove the pipe puller 50 and fill the hole 101 with cement grout.
[0072] For example, when using a ram in conjunction with the pipe puller 50, 2-3 workers can be stationed nearby for protection to ensure the safety of the entire pullback operation. For example, the pipe puller 50 is connected to the scrap steel pipe 100 by welding to ensure the stability of the pullback. For example, after each section of scrap steel pipe 100 is pulled back through the hole 101, a welder can directly cut off the pulled-back pipe and re-weld the pipe puller 50 to the unpulled section of pipe for the next pullback operation. For example, after all the scrap steel pipes 100 have been pulled back, the hole 101 needs to be filled with cement grout to prevent grout leakage during future tunnel boring machine (TBM) operations. For example, the cement grout requires a grout density greater than 1.8 g / cm³, a bleeding rate of less than 5%, a slump of 12-16 cm, a yield strength of greater than 800 Pascals after 20 hours, a compressive strength of R28 greater than 0.5 MPa after 28 days, and a permeability coefficient of less than 5 x 10⁻⁶. -5 Centimeters per second (cm / s).
[0073] For example, the trenchless pipeline clearing method in this embodiment can be directly applied to the treatment of medium-pressure natural gas pipelines. For example, the medium-pressure natural gas pipeline has a diameter of 300 mm, is made of steel, has a wall thickness of 1 cm, a maximum burial depth of approximately 11 m, and an actual burial depth of 10.5 m. For example, the medium-pressure natural gas pipeline's planar position is parallel to and intersects the tunnel section, with an impact range of approximately 140 m. Most of the pipeline is located in medium sand and silty clay layers. The length of the abandoned pipeline is approximately 170 m, with a burial depth ranging from 3 to 11 m. The tunnel elevation of the shield tunnel section is -6.586 to -5.45 m, and the center of gravity elevation of the shield is -7.47 m. For example, by using the trenchless pipeline clearing method in this embodiment to sequentially carry out the construction of the working well 10, injection of friction reducing agent, pipeline purging, installation of the milling pipe 30, welding of the scrap steel pipe 100 with the pipe puller 50, pipeline pullback, and filling of the hole 101, the purpose of trenchless clearing of long pipelines can be guaranteed, and the occurrence of other unexpected situations such as collapse can be avoided.
Claims
1. A trenchless pipeline clearing method, comprising: A working well (10) is set at each end of the scrapped steel pipe (100), and a traction machine (20) is set next to one of the working wells (10); Inject friction-reducing agent at intervals on the surface of the formation (200) up to the scrapped steel pipe (100); Install a temporary valve at the first end of the scrap steel pipe (100), purge the inside of the scrap steel pipe (100), and remove the temporary valve after purging. Connect the milling sleeve (30) to the traction machine (20), and connect the milling sleeve (30) to the scrap steel pipe (100) through the connecting ring (40). Clean the outside of the scrap steel pipe (100), and remove the milling sleeve (30) after cleaning. Connect the pipe puller (50) to the traction machine (20), and connect the scrap steel pipe (100) to the pipe puller (50) to pull back the scrap steel pipe (100) in sections.
2. The trenchless line clearing method of claim 1, wherein, The method of injecting friction-reducing agent at intervals on the formation surface (200) to the scrap steel pipe (100) includes: Multiple grouting holes are drilled at intervals and through the surface of the formation (200); An observation hole is installed between two adjacent grouting holes; The friction reducer is injected into the scrapped steel pipe (100) through the grouting hole until grout comes out of the observation hole, at which point the injection is stopped.
3. The trenchless line clearing method of claim 2, wherein, The spacing between two adjacent grouting holes is set to 10 meters.
4. The trenchless line clearing method of claim 2, wherein, The injection amount of the friction reducer ranges from 500 to 1000 kg.
5. The trenchless line clearing method of claim 1, wherein, The process of installing a temporary valve at the first end of the scrap steel pipe (100), purging the interior of the scrap steel pipe (100), and removing the temporary valve after purging includes: Select an open area that allows the discharge of waste and debris as the purge outlet; A temporary valve is installed at the first end of the scrapped steel pipe (100), and the temporary valve is located near the purge port; Use a compressed air machine to purge the inside of the scrap steel pipe (100), and when the pressure inside the scrap steel pipe (100) reaches the preset pressure during purging, quickly open the temporary valve to discharge dirt and debris; After completing the internal purging of the scrapped steel pipe (100), remove the temporary valve.
6. The trenchless line clearing method of claim 5, wherein, The temporary valve is installed with its outlet centerline offset from the vertical line by 30 degrees and facing upwards.
7. The trenchless line clearing method of claim 5, wherein, The preset pressure is set to 1.5 MPa.
8. The trenchless line clearing method of claim 1, wherein, The milling tube (30) includes a tube body (31) and a milling head (32). The connecting ring (40) is sleeved on the outside of the scrap steel pipe (100) and the tube body (31), and there are gaps between the connecting ring (40) and both the scrap steel pipe (100) and the tube body (31). During the cleaning process, the connecting ring (40) can move synchronously with the tube body (31) on the outside of the scrap steel pipe (100). The milling head (32) is set to clean the outside of the scrap steel pipe (100).
9. The trenchless line clearing method of claim 1, wherein, When the milling sleeve (30) cleans the scrap steel pipe (100) externally, bentonite is injected into the outside of the scrap steel pipe (100) to reinforce and lubricate it.
10. The trenchless line clearing method of claim 1, wherein, The process of connecting the pipe puller (50) to the traction machine (20) and connecting the scrap steel pipe (100) to the pipe puller (50) for segmented back-pulling of the scrap steel pipe (100) includes: The first end of the pipe puller (50) is connected to the traction machine (20), and the second end of the pipe puller (50) is connected to the first end of the scrap steel pipe (100). The second end of the scrap steel pipe (100) is operated by the pipe puller (50) in conjunction with the tamping hammer. The scrap steel pipe (100) is pulled back in 10-meter segments. After each segment is pulled out, the pulled-out segment of scrap steel pipe (100) is cut off from the unpulled part. Then the pipe puller (50) is reconnected to the unpulled part for pullback. After all the scrapped steel pipes (100) have been pulled back, remove the pipe puller (50) and fill the hole (101) with cement grout.