Water-rich sand layer large-section rectangular pipe jacking machine and pipe joint coordinated back-off construction method

Abstract

The application provides a water-rich sand layer large-section rectangular pipe jacking machine and a pipe joint cooperative back-off construction method, which comprises the following steps: establishing an outer peripheral water-stopping system; controlling slurry in different regions; establishing a decision system based on back-off state judgment; selecting a natural back-off or passive back-off process path according to the actual back-off condition of the pipe jacking machine; realizing the synchronous back-off of the pipe jacking machine and the pipe joint through the cooperative matching of the counterforce support system and the jacking system; and adopting a profile steel composite support structure to complete the permanent closure of the hole. The application realizes the cooperative operation of the pipe jacking machine and the pipe joint by establishing a systematic back-off technical system, effectively controls the filling body performance by adopting a regional differential slurry proportioning strategy, improves the adaptability and reliability of the construction by establishing a multi-mode back-off working condition response system, ensures the safety and controllability of the back-off process through the counterforce cooperative system, and stabilizes the hole and ensures the post-pipe jacking machine re-pushing strength condition by adopting a combined support technology.

Description

Technical Field

[0001] This invention belongs to the field of underground engineering pipe jacking construction technology, and particularly relates to a large-section rectangular pipe jacking machine for water-rich sand layers and a method for coordinated pipe section retreat construction. Background Technology

[0002] During the construction of large-section rectangular pipe jacking projects, retreat operations of the pipe jacking machine and pipe sections are often necessary when geological conditions change or construction plans are adjusted. Especially in water-rich strata, retreat operations face numerous technical challenges: poor stratum stability leading to soil erosion; high retreat resistance causing equipment jamming; and difficulty in controlling grout properties, affecting retreat effectiveness. Traditional retreat methods typically employ uniform construction techniques and grout ratios, lacking differentiated treatment measures for different geological conditions and retreat stages, making it difficult to guarantee the safety and controllability of the retreat process. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method for the coordinated retreat of a large-section rectangular pipe jacking machine and pipe sections in water-rich sandy strata. This method is safe, reliable, and highly adaptable, and solves key technical challenges in the retreat process by establishing a systematic technical framework.

[0004] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0005] A method for the coordinated retreat of a large-section rectangular pipe jacking machine and pipe sections in water-rich sand layers includes the following steps:

[0006] Step 1: Establish an external waterproofing system;

[0007] Step 2: Differentiated slurry control by region;

[0008] Step 3: Multi-mode retraction operation to achieve synchronous retraction of the pipe jacking machine and the pipe section;

[0009] Step 4: Use combined support and sealing techniques to seal the opening.

[0010] Furthermore, in step 1, a combined water-stop curtain technology is adopted in conjunction with a dewatering system to form a stable retreat operation environment; specifically, a water-stop curtain is constructed around the reinforcement area of ​​the starting well, and after the reinforcement is completed, dewatering wells and monitoring points are drilled inside and outside the reinforced area.

[0011] Furthermore, in step 2, different grout mix ratio schemes are designed according to the geological characteristics and retreat strength requirements of the retreat section. That is, different grout mix ratios are used in the front retreat section and the rear portal section to achieve a gradient distribution of the filling strength. In actual construction, the mixed grout is put into the feeding port of the mud pump, and the mud pump pressurizes and sends the mixed grout to the breast plate grouting hole through the mud pipe and pumps it into the soil chamber. Then the main jacking cylinder is released, and it is observed whether the shield body and the pipe section of the pipe jacking machine retreat naturally.

[0012] Furthermore, in step 3, based on the actual retraction of the pipe jacking machine, a natural retraction or passive retraction process path is selected. The natural retraction mode uses a device to improve the retraction conditions, while the passive retraction mode uses a device to provide auxiliary power. Through the coordinated cooperation of the reaction support system and the jacking system, the synchronous retraction of the pipe jacking machine and the pipe section is achieved.

[0013] Furthermore, the natural rollback process path is as follows:

[0014] Stop shoveling, with the main jacking cylinder pressing against the U-shaped jacking iron. Erect steel pipe and coupler scaffolding near the tunnel entrance. Remove the water-stopping outer casing and curtain plate at the tunnel entrance ring beam. Insert steel strips between the shell and wire brush from the tunnel entrance side and weld them to the tunnel jacking machine shield. Begin shoveling into the soil chamber, with the main jacking cylinder retracting synchronously with the shoveling until sufficient space is available for the pipe section to be lifted out. Weld blocks to the pre-embedded irons on both sides of the lower part of the first and second pipe sections and at the middle position of the upper part. Use jacks to separate the first and second pipe sections, lift out the first pipe section, and then the main jacking cylinder... The U-shaped jacking iron is used to hold the second pipe section in place. Mud is then pumped into the soil chamber in coordination with the main jacking cylinder until the cutter tip retracts to the outside of the retaining structure. The jacking machine shield body is then welded to the horizontal and vertical steel sections. Anti-retraction pins are inserted into the anti-retraction holes of the pipe sections. If there is a gap between the anti-retraction pins and the anti-retraction baffle, steel wedges are inserted for fixation. Steel composite piles are constructed on the outside of the jacking machine shield cutter tip, and water-stop piles are constructed on the outside of the piles. After the strength is achieved, a water-stop curtain is constructed between the retaining structure and the steel composite piles. Once the strength meets the requirements, the jacking machine shield body is disassembled and hoisted out of the well.

[0015] Furthermore, the passive rollback process path is as follows:

[0016] Stop shoveling; the main jacking cylinder holds the U-shaped jacking iron in place. Use the pipe-removing cylinder to separate the tunnel jacking machine shield and the pipe section until a steel support is installed between the end of the pipe section and the tail of the tunnel jacking machine shield, with the main jacking cylinder supporting the U-shaped jacking iron. Erect steel pipe and coupler scaffolding near the tunnel entrance. Remove the water-stopping outer box and curtain board at the tunnel entrance ring beam. Insert steel strips between the shell and the wire brush from the tunnel entrance side and weld them to the tunnel jacking machine shield. Weld the reaction frame to the end of the tunnel jacking machine shield, and then install the jacks. Begin shoveling into the soil chamber, with the jacks extending slowly and synchronously with the shoveling to ensure consistent cylinder strokes. The pipe-removing cylinder and jacks retract in tandem until the jacks reach 80% of their stroke. Re-weld the reaction frame to the outside of the tunnel jacking machine shield and continue applying the retraction reaction force until the pipe section spigot is fully inserted. Entering the tail of the pipe jacking machine shield; when sufficient space is available for lifting pipe sections, weld stops to the pre-embedded iron on both sides of the lower part of the first and second pipe sections and at the middle position of the upper part. Use jacks to separate the first and second pipe sections, lift out the first pipe section, and push the U-shaped jacking iron with the main jacking cylinder to hold the second pipe section in place; repeat the above actions until the cutter tip retracts to the outside of the retaining structure, weld the pipe jacking machine shield to the horizontal and vertical steel sections, insert the anti-reverse pin into the anti-reverse hole of the pipe section, and if there is a gap between the anti-reverse pin and the anti-reverse baffle, insert steel wedges to fix it; construct steel composite piles on the outside of the cutter tip of the pipe jacking machine shield, and construct joint water-stop piles on the outside of the pile body. After the strength is equalized, construct a water-stop curtain between the retaining structure and the steel composite piles; after the strength meets the standard, disassemble the pipe jacking machine shield and lift it out of the well.

[0017] Furthermore, in step 4, a steel composite support structure is used to permanently seal the opening, ensuring its long-term stability and meeting the strength requirements for subsequent pipe jacking.

[0018] The present invention has the following beneficial effects:

[0019] 1. By establishing a systematic retraction technology system, the coordinated operation of the pipe jacking machine and the pipe section was realized;

[0020] 2. By adopting a regionally differentiated slurry ratio strategy, the performance of the filler was effectively controlled;

[0021] 3. A multi-mode rollback response system was established, which improved the adaptability and reliability of construction.

[0022] 4. The reaction force coordination system ensures the safety and controllability of the retraction process;

[0023] 5. Adopt combined support technology to stabilize the tunnel entrance and ensure the strength conditions for subsequent pipe jacking machine push-back.

[0024] This invention is applicable to large-section rectangular pipe jacking projects under various complex geological conditions, and has significant engineering application value and promotion prospects. Attached Figure Description

[0025] Figure 1 This is a flowchart of the construction method for the large-section rectangular pipe jacking machine and pipe section coordinated retreat in water-rich sand layers as described in this invention;

[0026] Figure 2 This is a schematic diagram showing the arrangement of the reaction frame and jacks;

[0027] Figure 3 Schematic diagram of grout injection;

[0028] Figure 4 This is a schematic diagram of the passive rollback process;

[0029] Figure 5 This is a detailed schematic diagram of the reaction frame;

[0030] Figure 6 Schematic diagram of a closed opening in a steel composite support structure;

[0031] Figure 7 A detailed schematic diagram of the stop-return mechanism.

[0032] In the diagram: 1. Reaction frame, 2. Jack, 3. Shield body of the pipe jacking machine, 4. Mud pipe, 5. Mud pump, 6. Feed port, 7. Grouting hole of the breast plate, 8. Main jacking cylinder, 9. Portal ring beam, 10. First pipe section, 11. Second pipe section, 12. Water-stopping reinforcement pile, 13. Steel composite pile, 14. Joint water-stopping pile, 15. Water-stopping curtain, 16. Horizontal steel section, 17. Vertical steel section, 18. Backlash pin, 19. Backlash baffle, 21. Pipe detachment cylinder, 22. Backlash hole of pipe section, 23. Steel support pier; 1.1. Steel triangular plate, 1.2. Steel section, 1.3. Sealing plate, 1.4. Stiffening rib. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0034] Reference Figures 1 to 7 As shown, the method for coordinated retreat construction of large-section rectangular pipe jacking machine and pipe sections in water-rich sand layers according to the present invention specifically includes the following processes:

[0035] Step 1: Establish an external waterproofing system;

[0036] A combined waterproof curtain technology, in conjunction with a dewatering system, creates a stable working environment for retreat operations. The external waterproofing system is composed of various support methods, forming a multi-layered waterproofing protection system. For example... Figure 6 As shown, in the specific construction, a water-stop curtain 15 is installed around the reinforcement area of ​​the starting well. After the reinforcement is completed, dewatering wells and monitoring points are installed inside and outside the reinforcement area, and the pipe jacking machine is ready to retreat.

[0037] Step 2: Differentiated slurry control by region;

[0038] Based on the geological characteristics and strength requirements of the retreat section, different grout mix proportions were designed, employing different component proportions in the front retreat section and the rear portal section to achieve a gradient distribution of fill strength. In actual construction, such as... Figure 3 As shown, the proportioned slurry is fed into the feed port 6 of the mud pump 5. The mud pump 5 pressurizes and sends the proportioned slurry to the grouting hole 7 of the breast plate through the mud pipe 4 and pumps it into the soil chamber. Then the main jacking cylinder 8 is released, and it is observed whether the shield body 3 and the pipe section of the pipe jacking machine retract naturally.

[0039] Step 3: Handling multi-mode rollback scenarios;

[0040] A decision-making system based on the retraction status is established to select either natural or passive retraction process paths according to the actual retraction situation of the pipe jacking machine. The natural retraction mode employs devices to improve retraction conditions, while the passive retraction mode uses devices to provide auxiliary power. Synchronous retraction of the pipe jacking machine and the pipe section is achieved through the coordinated operation of the reaction support system and the jacking system. This coordinated retraction operation is accomplished by establishing a reaction force transmission system to effectively apply and balance the retraction force.

[0041] Scenario 1: Natural retraction occurs. Stop shoveling, with the main jacking cylinder 8 holding the U-shaped jacking iron in place. Erect steel pipe and coupler scaffolding near the tunnel entrance. Remove the water-stopping outer casing and curtain plate at the tunnel entrance ring beam 9. Insert steel strips between the shell and wire brush from the tunnel entrance side and weld them to the tunnel jacking machine shield 3. Begin shoveling into the soil chamber, with the main jacking cylinder 8 retracting synchronously with the shoveling until sufficient space is available for lifting the pipe section. Weld blocks to the pre-embedded iron on both sides of the lower part of the first pipe section 10 and the middle position of the upper part of the second pipe section 11. Use jacks to separate the first pipe section 10 and the second pipe section 11, lift out the first pipe section 10, and have the main jacking cylinder 8 push the U-shaped jacking iron to hold the second pipe section 11 in place. Subsequently, mud is pumped into the soil chamber in coordination with the main jacking cylinder 8 until the cutter tip retracts to the outside of the retaining structure. The jacking machine shield body 3 is then welded to the horizontal steel section 16 and the vertical steel section 17. The anti-reverse hole 22 of the pipe section is inserted with the anti-reverse pin 18. If there is a gap between the anti-reverse pin 18 and the anti-reverse baffle 19, a steel wedge is inserted for fixation. Steel composite piles 13 are constructed on the outside of the cutter tip of the jacking machine shield body 3, and water-stop piles 14 are constructed on the outside of the pile body. After the strength is achieved, a water-stop curtain 15 is constructed between the retaining structure and the steel composite piles 13. After the strength meets the standard, the jacking machine shield body 3 is disassembled and hoisted out of the well.

[0042] Scenario 2: No natural retraction (i.e., passive retraction). Stop mud blasting, and the main jacking cylinder 8 holds the U-shaped jacking iron. Use the pipe-detaching cylinder 21 to separate the tunnel jacking machine shield 3 from the pipe section until a steel support 25 is installed at the lower part between the end of the pipe section and the tail of the tunnel jacking machine shield 3, and the main jacking cylinder 8 holds the U-shaped jacking iron. Erect steel pipe and coupler scaffolding near the tunnel entrance. Remove the water-stopping outer box and curtain board at the tunnel entrance ring beam 9. Insert steel strips between the shell and the wire brush from the tunnel entrance side and weld them to the tunnel jacking machine shield 3. Weld the reaction frame 1 to the end of the tunnel jacking machine shield 3, and then install the jack 2. Begin mud blasting into the soil chamber, with the jack 2 extending slowly in sync with the mud blasting, ensuring consistent cylinder stroke. The pipe-detaching cylinder 21 and the jack 2 retract in coordination until the jack 2 reaches 80% of its stroke, then re-weld the reaction frame 1 to the outside of the tunnel jacking machine shield 3 and continue applying the retraction reaction force. Continue until all pipe section spigots are inserted into the tail of the tunnel jacking machine shield 3. When sufficient space is available for lifting the pipe section, weld stop blocks to the pre-embedded iron on both sides of the lower part of the first pipe section 10 and the middle position of the upper part of the second pipe section 11. Use jacks to separate the first pipe section 10 and the second pipe section 11, lift out the first pipe section 10, and push the U-shaped jacking iron with the main jacking cylinder 8 to hold the second pipe section 11. Repeat the above actions until the cutter tip retracts to the outside of the retaining structure. Weld the tunnel jacking machine shield 3 to the horizontal steel 16 and the vertical steel 17. Insert the anti-retraction pin 18 into the anti-retraction hole 22 of the pipe section. If there is a gap between the anti-retraction pin 18 and the anti-retraction baffle 19, insert steel wedges to fix it. Install steel composite piles 13 on the outside of the cutter tip of the tunnel jacking machine shield 3, and install water-stop piles 14 on the outside of the pile body. After the strength is equalized, install a water-stop curtain 15 between the retaining structure and the steel composite piles 13. Once the strength meets the standard, the shield body 3 of the pipe jacking machine will be disassembled and hoisted out of the well.

[0043] Step 4: Combined support and closure techniques;

[0044] A composite steel support structure is adopted to permanently seal the opening, ensuring its long-term stability and meeting the strength requirements for subsequent pipe jacking.

[0045] The reaction frame 1 includes a steel triangular plate 1.1, a structural steel section 1.2, a sealing plate 1.3, and stiffening ribs 1.4.

[0046] On the other side of the steel composite pile 13, a water-stopping reinforcement pile 12 is also constructed.

[0047] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for constructing a large-section rectangular pipe jacking machine and a coordinated pipe section retreat method in water-rich sand layers, characterized in that... The process includes the following: Step 1: Establish an external waterproofing system; Step 2: Differentiated slurry control by region; Step 3: Multi-mode retraction operation to achieve synchronous retraction of the pipe jacking machine and the pipe section; Step 4: Use combined support and sealing techniques to seal the opening.

2. The method for co-construction of a large-section rectangular pipe jacking machine and pipe sections in water-rich sand layers according to claim 1, characterized in that, In step 1, a combined water-stop curtain technology is used in conjunction with a dewatering system to form a stable retreat operation environment; specifically, a water-stop curtain (15) is constructed around the reinforcement area of ​​the starting well, and after equal strength, dewatering wells and monitoring points are drilled inside and outside the reinforced body.

3. The method for co-construction of a large-section rectangular pipe jacking machine and pipe sections in water-rich sand layers according to claim 1, characterized in that, In step 2, different grout ratio schemes are designed according to the geological characteristics and retreat strength requirements of the retreat section. That is, different grout ratios are used in the front retreat section and the rear portal section to achieve a gradient distribution of the strength of the filling body. In actual construction, the grout ratio is put into the feed port (6) of the mud pump (5). The mud pump (5) pressurizes and sends the grout ratio to the breast plate grouting hole (7) through the mud pipe (4) and pumps it into the soil chamber. Then the main jacking cylinder (8) is released, and the shield body (3) of the pipe jacking machine and the pipe section are observed to see if they retreat naturally.

4. The method for co-construction of a large-section rectangular pipe jacking machine and pipe sections in water-rich sand layers according to claim 1, characterized in that, In step 3, the natural or passive retraction process path is selected based on the actual retraction situation of the pipe jacking machine. The natural retraction mode uses a device to improve the retraction conditions, while the passive retraction mode uses a device to provide auxiliary power. Through the coordinated cooperation of the reaction support system and the jacking system, the synchronous retraction of the pipe jacking machine and the pipe section is achieved.

5. The method for co-construction of a large-section rectangular pipe jacking machine and pipe section retraction in water-rich sand layers according to claim 4, characterized in that, The natural rollback process path is as follows: Stop shoveling, the main jacking cylinder (8) holds the U-shaped jacking iron, and a steel pipe fastener scaffold is erected near the tunnel entrance; the water-stopping outer box and curtain board at the tunnel entrance ring beam (9) are removed; steel strips are inserted between the shell and the wire brush from the tunnel entrance side and welded to the tunnel jacking machine shield body (3); start shoveling into the soil chamber, the main jacking cylinder (8) retracts synchronously with the shoveling until the space for the pipe section to be lifted out is met, and the stop blocks are welded on the pre-embedded iron on both sides of the lower part of the first pipe section (10) and the middle position of the upper part of the second pipe section (11), and the first pipe section (10) is lifted out using jacks, and the main jacking cylinder (8) pushes the U-shaped jacking iron to hold the second pipe section (11) to the ground. Section pipe section (11); subsequently, mud is pumped into the soil chamber in coordination with the main jacking cylinder (8) until the tip of the cutter retracts to the outside of the retaining structure. The shield body (3) of the jacking machine is welded to the horizontal steel (16) and the vertical steel (17). The anti-retraction hole (22) of the pipe section is inserted with the anti-retraction pin (18). If there is a gap between the anti-retraction pin (18) and the anti-retraction baffle (19), a steel wedge is inserted for fixation. Steel composite piles (13) are installed on the outside of the tip of the shield body (3) of the jacking machine. Water-stopping piles (14) are installed on the outside of the pile body. After the strength is equalized, a water-stopping curtain (15) is installed between the retaining structure and the steel composite piles (13). After the strength meets the standard, the shield body (3) of the jacking machine is disassembled and hoisted out of the well.

6. The method for co-construction of a large-section rectangular pipe jacking machine and pipe section retraction in water-rich sand layers according to claim 4, characterized in that, The passive rollback process path is as follows: Stop shoveling, and the main jacking cylinder (8) holds the U-shaped top iron; use the pipe-removing cylinder (21) to separate the pipe jacking machine shield (3) and the pipe section until a steel support (25) is installed at the bottom between the end of the pipe section and the tail of the pipe jacking machine shield (3), and the main jacking cylinder (8) holds the U-shaped top iron; erect a steel pipe fastener scaffold close to the tunnel entrance; remove the water-stopping outer box and curtain board at the tunnel entrance ring beam (9); insert steel strips between the shell and the wire brush from the tunnel entrance side and weld them to the pipe jacking machine shield (3); weld the reaction frame (1) to the end of the pipe jacking machine shield (3), and then install the jack (2); start shoveling mud into the soil chamber, and the jack (2) extends slowly in sync with the shoveling to ensure that the cylinder stroke is consistent; The pipe-removing cylinder (21) and the jack (2) retract in coordination until the jack (2) reaches 80% of its stroke. The reaction frame (1) is then re-welded to the outside of the pipe jacking machine shield (3), and the retraction reaction force continues to be applied until the pipe section spigot is fully inserted into the tail of the pipe jacking machine shield (3). When the space for lifting the pipe section is sufficient, stop blocks are welded to the pre-embedded iron on both sides of the lower part of the first pipe section (10) and the middle position of the upper part. The jack is used to separate the first pipe section (10) and the second pipe section (11), and the first pipe section (10) is lifted out. The main jacking cylinder (8) pushes the U-shaped jacking iron to hold the second pipe section (11) in place. 1) Repeat the above actions until the blade tip retracts to the outside of the retaining structure. Weld the jacking machine shield (3) to the horizontal steel (16) and vertical steel (17). Insert the anti-retraction pin (18) into the anti-retraction hole (22) of the pipe section. If there is a gap between the anti-retraction pin (18) and the anti-retraction baffle (19), insert a steel wedge to fix it. Make a steel composite pile (13) on the outside of the blade tip of the jacking machine shield (3). Make a water-stop pile (14) on the outside of the pile body. After the strength is equalized, make a water-stop curtain (15) between the retaining structure and the steel composite pile (13). After the strength meets the standard, disassemble the jacking machine shield (3) and hoist it out of the well.

7. The method for co-construction of a large-section rectangular pipe jacking machine and pipe sections in water-rich sand layers according to claim 1, characterized in that, In step 4, a steel composite support structure is used to permanently seal the opening, ensuring its long-term stability and meeting the strength requirements for subsequent pipe jacking.

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