Pipe jacking underwater counterweight device and construction method

Abstract

This invention discloses an underwater counterweight device and construction method for pipe jacking, comprising the following steps: S1: Calculate the counterweight weight and select the size of the airbag; S2: Place the airbag inside the pipe jacking machine head behind it; S3: Fill the airbag with gas to maintain air pressure so that the airbag is pressed tightly against the inner wall of the pipe jacking machine; S4: Jacking the pipe until the pipe jacking machine head emerges from the soil, and simultaneously inject ballast water into the airbag to replace the gas, maintaining stable air pressure, and the airbag begins to balance buoyancy; S5: The pipe jacking continues to advance to the designed position; S6: Begin retrieving the pipe jacking machine head, cutting the pipe behind the machine head, and simultaneously inflating the airbag to replace the ballast water, maintaining stable air pressure, and balancing the gradually decreasing buoyancy; S7: After the pipe jacking machine head detaches, release the air pressure in the airbag, causing the airbag to detach from the inner wall of the pipe jacking machine; S8: The airbag naturally floats out of the pipe jacking machine under the buoyancy of the water, and the airbag is retrieved. This method is simple and effective, ensuring smooth increases and decreases in the counterweight of the pipe jacking system, precise control, and guaranteeing the anti-buoyancy effect of the counterweight installed inside the pipe.

Description

Technical Field

[0001] This invention belongs to the field of pipe jacking construction technology, specifically relating to an underwater counterweight device and construction method for pipe jacking. Background Technology

[0002] Pipe jacking construction has been widely adopted in the construction and renovation of urban pipelines due to its advantages such as no excavation required and minimal impact on the surrounding environment. However, when pipe jacking approaches or crosses complex terrains such as rivers, lakes, and seas, resisting the buoyancy of high-level groundwater is one of the technical challenges that needs to be addressed during pipe jacking construction. Using counterweights within the pipe is one method to solve the problem of pipe buoyancy. This typically involves placing counterweights inside the pipe and moving them to suitable positions according to the actual anti-buoyancy requirements during construction. However, this method may have certain problems: generally, the counterweights are quite heavy, making it difficult to move them to suitable points within the pipe. Furthermore, as the pipe jacks deeper into the soil, it is difficult to keep the counterweights stably at the points when the pipe encounters the risk of buoyancy, as they are prone to slippage, threatening the safety of on-site construction personnel and damaging equipment inside the pipe. Additionally, the weight of the counterweights cannot be dynamically adjusted in a timely manner, resulting in poor anti-buoyancy performance. Summary of the Invention

[0003] To overcome the technical defects in existing pipe jacking construction that make it difficult to ensure the relative stability of the counterweight, posing a threat to personnel safety and damaging equipment inside the pipe, this invention provides an underwater counterweight device and construction method for pipe jacking. While ensuring the anti-buoyancy requirements of pipe jacking construction, it avoids slippage during counterweight anti-buoyancy. The counterweight weight can be adjusted at different stages of pipe jacking construction to meet different counterweight requirements. The operation is safe, and the above-mentioned technical problems are solved.

[0004] An underwater counterweight device for pipe jacking includes an airbag, airbag protrusions, and airbag grooves. The airbag has protrusions and grooves evenly and alternately distributed along its circumference. Anti-slip rubber is provided on the protrusions. The upper part of the airbag has inflation and deflation holes and pipes, through which compressed gas can be filled and released. The lower part of the airbag has water inlet and outlet holes and pipes, through which water can be filled and drained. When inflated, the airbag has a cylindrical structure with both ends bulging. When inflated, the airbag can fit tightly against the inner wall of the pipe jacking, and the anti-slip rubber on the protrusions ensures that the airbag's position in the pipe jacking is relatively fixed.

[0005] A construction method for an underwater counterweight device for pipe jacking includes the following construction steps:

[0006] S1: Calculate the required airbag size based on the cross-section, dimensions, weight, hydrogeological conditions, length submerged in water flow, and weight of the pipe jacking machine head;

[0007] The volume of the airbag satisfies the following formula:

[0008]

[0009] S2: The airbag is placed inside the jacking pipe behind the jacking machine head by manual installation. The inflation and deflation pipes are connected to the inflation and deflation holes, and the injection and drainage pipes are connected to the injection and drainage holes.

[0010] S3:

[0011] ① After confirming that the inflation function of the inflation and deflation pipes is normal and the water injection function of the water injection and drainage pipes is normal, the operator should leave the jacking pipe to avoid danger during the pressurization of the airbag;

[0012] ② Inflate the airbag with gas through the inflation / deflation pipe, maintain the air pressure so that the airbag bulges up and presses tightly against the inner wall of the top tube, ensuring that the anti-slip rubber is in close contact with the inner wall of the top tube. The air pressure inside the airbag satisfies the following formula:

[0013]

[0014] This pressure should be maintained as the working pressure until S6;

[0015] S4:

[0016] ① The pipe jacking is advanced until the pipe jacking machine head emerges from the soil;

[0017] ② Begin injecting ballast water into the airbag to replace the gas and maintain stable air pressure. The airbag then begins to balance buoyancy.

[0018] S5: The jacking pipe continues to advance to the design position. During the process, the rate at which ballast water is injected into the airbag to replace the gas is controlled according to the exposed length of the jacking pipe, so as to maintain stable air pressure and balance the gradually increasing buoyancy.

[0019] The amount of water injected into the airbag satisfies the following formula:

[0020]

[0021] V 水 ≥0;

[0022] S6:

[0023] ① The jacking machine head is retrieved, and the jacking pipe behind the jacking machine head is cut, allowing ambient water to enter the jacking pipe;

[0024] ② Ambient water enters the space behind the airbag through the airbag groove, reducing the buoyancy of the jacking pipe;

[0025] ③ Inflate the airbag to replace the ballast water in the airbag, maintain stable air pressure, and balance the gradually decreasing buoyancy;

[0026] The amount of water in the airbag satisfies the following formula:

[0027]

[0028] S7: After the jacking machine head is disengaged, release the air pressure of the airbag to allow the airbag to detach from the inner wall of the jacking pipe.

[0029] S8: The airbag floats out of the top tube naturally under the buoyancy of the water, and the airbag is recovered.

[0030] In the above-mentioned underwater counterweight device and construction method for pipe jacking, in step S1, the airbag is provided with an airbag protrusion, an airbag groove, an inflation / extension hole, an inflation / extension pipe, an injection / drainage hole, an injection / drainage pipe, and anti-slip rubber.

[0031] In the above-mentioned underwater counterweight device and construction method for pipe jacking, the volume V of the airbag in step S1 should not be less than the calculated volume, and the ratio u2 of the area of ​​the anti-slip rubber to the contact area of ​​the airbag surface on the inner wall of the pipe jacking should be ≥0.8.

[0032] In the above-mentioned underwater counterweight device and construction method for pipe jacking, in step S2, the airbag should be placed in the pipe jacking machine head behind the pipe jacking machine in a non-inflated state. The axis of the airbag should be parallel to the axis of the pipe jacking machine, and the airbag should not be folded or twisted.

[0033] In the aforementioned device and construction method for underwater counterweight for pipe jacking, in step S3, anti-slip rubber is fully distributed on the protrusions of the airbag. To ensure that the airbag and the pipe do not slip relative to each other, the airbag pressure P should be such that the airbag can still press tightly against the inner wall of the pipe while resisting strong ambient water pressure, and generate sufficient friction to resist the ambient water pressure from in front of the airbag.

[0034] In the above-mentioned device and construction method for underwater counterweight for pipe jacking, in step S6, the pipe behind the pipe jacking machine head is cut, and ambient water enters the internal space of the pipe jacking machine head and the airbag.

[0035] In the aforementioned underwater counterweight device and construction method for pipe jacking, in step S6, ambient water enters the rear pipe jacking space of the airbag through the groove between the pipe jacking head and the airbag, from the internal space of the pipe jacking machine and the airbag. During this process:

[0036] The pressure exerted by the surrounding water on the airbag is:

[0037] F 水 =ρ 水 ×g×underwater depth at the center of the pipe jacking section h;

[0038] The airbag is subjected to pressure from the surrounding water.

[0039] F 水 =(ρ 水 ×g×underwater depth at the center of the jacking pipe (h)×π×radius of the jacking pipe (r^2).

[0040] In the above-mentioned underwater counterweight device and construction method for pipe jacking, in step S6, the maximum static friction force between the airbag and the inner wall of the pipe jacking is:

[0041] f = (Airbag pressure P - Ambient water pressure P) 水 )×π×jacking pipe diameter d×airbag length L×μ1×μ2;

[0042] Where μ1 is the friction coefficient between the anti-slip rubber and the jacking pipe ≥ 0.8, and μ2 is the ratio of the anti-slip rubber area to the contact area of ​​the airbag surface on the inner wall of the jacking pipe ≥ 0.8;

[0043] The maximum static friction between the airbag and the inner wall of the jacking pipe is:

[0044] f ≥ (airbag pressure P - ambient water pressure P) 水 )×π×jacking pipe diameter d×airbag length L×0.64>(airbag pressure P - ambient water pressure P) 水 )×π×jacking pipe half r×airbag length L.

[0045] In step S6 of the above-mentioned underwater counterweight device and construction method for pipe jacking, the airbag and the inner wall of the pipe jacking should meet the maximum static friction force:

[0046] f > (airbag pressure P - ambient water pressure P) 水 )×π×jacking pipe half r×airbag length L>pressure F of ambient water in front of the airbag 水 ;

[0047] F 水 = (Airbag pressure P - Ambient water pressure P) 水 )×π×jacking pipe half r×airbag length L>(ρ 水 ×g×underwater depth at the center of the jacking pipe h)×π×radius of the jacking pipe r^2;

[0048] Airbag pressure P ≥ (ρ 水 ×g×underwater depth at the center of the pipe jacking (h)×(airbag length L+pipe radius r) / airbag length L, the airbag pressure P should be increased by one atmosphere as a safety reserve, therefore, during the airbag operation phase,

[0049]

[0050] In the above-mentioned underwater counterweight device and construction method for pipe jacking, in step S6, ambient water enters the internal space of the pipe jacking behind the airbag, the buoyancy of the pipe jacking decreases until it becomes 0, and the airbag discharges part of the ballast water to provide buoyancy to balance part of the weight of the pipe jacking, preventing the pipe jacking from floating due to excessive buoyancy of the airbag.

[0051] In the above-mentioned underwater counterweight device and construction method for pipe jacking, in step S6, the buoyancy of the airbag F1 = the air volume of the airbag V 气×ρ 水 ×g=(airbag volume V - airbag water volume V) 水 )×ρ 水 ×g;

[0052] In the above-mentioned underwater counterweight device and construction method for pipe jacking, in step S6, the buoyancy of the airbag F1 ≤ the designed exposed section weight of the pipe jacking G1 - the buoyancy of the pipe body F2;

[0053] Buoyancy of the jacking pipe body F2 = Design weight of the exposed section of the jacking pipe G1 × (ρ 钢 -ρ 水 ) / ρsteel = Design exposed section weight of jacking pipe G1 × 0.87;

[0054] In the above-mentioned underwater counterweight device and construction method for pipe jacking, the buoyancy of the airbag in step S6 is:

[0055] F1 = (Airbag volume V - Airbag water volume V) 水 )×ρwater×g<Design weight of exposed section of jacking pipe G1×0.87;

[0056] Airbag water volume V 水 > Airbag volume V - Weight of exposed section of jacking pipe design G1 × 0.87 / (ρ 水 ×g);

[0057] As a safety reserve;

[0058] In the above-mentioned underwater counterweight device and construction method for pipe jacking, in step S7, after the pipe jacking machine head is detached, the air pressure of the airbag is released, and some gas is discharged, so that the cross-section of the airbag is smaller than that of the pipe jacking, causing the airbag to bulge and the anti-slip rubber to detach from the inner wall of the pipe jacking.

[0059] In summary, the technical solution conceived by this invention, compared with the prior art, can achieve the following beneficial effects:

[0060] 1. The construction method of the underwater counterweight device for pipe jacking of the present invention is simple and reasonable, without complicated and redundant procedures, ensuring the anti-buoyancy requirements of pipe jacking construction, avoiding slippage during counterweight anti-buoyancy, dynamic operation, the counterweight weight can be adjusted at different stages of pipe jacking construction to meet the counterweight requirements of different weights, safe operation, after the airbag is installed, no personnel need to enter the pipe jacking to work, and it can be remotely controlled throughout the process.

[0061] 2. The present invention provides an underwater counterweight device for pipe jacking, which uses an inflation and deflation pipe and an injection and drainage pipe to dynamically adjust the water volume of the airbag while maintaining stable air pressure, thereby meeting the counterweight requirements. Attached Figure Description

[0062] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0063] Figure 1 This is an overall structural diagram of the airbag in the underwater counterweight device for pipe jacking according to the present invention;

[0064] Figure 2 This is a cross-sectional view of the airbag in an underwater counterweight device for pipe jacking according to the present invention.

[0065] Figure 3 This is a front view of the airbag in the jacking pipe of the underwater counterweight device of the present invention;

[0066] Figure 4 This is a side view of the airbag in the jacking pipe of the underwater counterweight device of the present invention;

[0067] Figure 5 This is a construction flowchart of a construction method for an underwater counterweight device for pipe jacking according to the present invention;

[0068] Figure 6 This is a schematic diagram of the force on the airbag in construction step S1 of the underwater counterweight device for pipe jacking according to the present invention.

[0069] Figure 7 This is a construction diagram of step S2 in the construction method of an underwater counterweight device for pipe jacking according to the present invention;

[0070] Figure 8 This is a construction diagram of step S3 in the construction method of an underwater counterweight device for pipe jacking according to the present invention.

[0071] Figure 9 This is a construction diagram of step S4 in the construction method of an underwater counterweight device for pipe jacking according to the present invention.

[0072] Figure 10 This is a construction diagram of step S5 in the construction method of an underwater counterweight device for pipe jacking according to the present invention.

[0073] Figure 11 This is a construction diagram of step S6 in the construction method of an underwater counterweight device for pipe jacking according to the present invention.

[0074] Figure 12 This is a construction diagram of step S7 in the construction method of an underwater counterweight device for pipe jacking according to the present invention;

[0075] Figure 13 This is a construction diagram of step S8 in the construction method of an underwater counterweight device for pipe jacking according to the present invention.

[0076] In the diagram: 1-jacking pipe, 2-airbag, 3-airbag protrusion, 4-airbag groove, 5-inflation and exhaust hole, 6-inflation and exhaust pipe, 7-injection and drainage hole, 8-injection and drainage pipe, 9-anti-slip rubber. Detailed Implementation

[0077] like Figure 1 and Figure 2 The diagram shows the overall structure and cross-sectional view of an underwater counterweight device for pipe jacking according to the present invention. It includes an airbag 2, an airbag protrusion 3, and an airbag groove 4. The airbag 2 has the airbag protrusion 3 and the airbag groove 4 evenly and alternately distributed along the circumference. The airbag protrusion 3 is provided with anti-slip rubber 9. The upper part of the airbag 2 is provided with inflation and deflation holes 5 and inflation and deflation pipes 6. Compressed gas can be filled into and released into the airbag through the inflation and deflation holes 5 and the inflation and deflation pipes 6. The lower part of the airbag 2 is provided with injection and drainage holes 7 and injection and drainage pipes 8. Water can be injected into and drained into the airbag through the injection and drainage holes 7 and the injection and drainage pipes 8.

[0078] like Figure 3 and Figure 4 The image shows a front view and a side view of the airbag in the jacking pipe of an underwater counterweight device. The airbag 2 has a cylindrical structure when inflated, with both ends bulging. When inflated, the airbag 2 can fit tightly against the inner wall of the jacking pipe 1, and the anti-slip rubber 9 on the airbag protrusion 3 ensures that the position of the airbag 2 in the jacking pipe 1 is relatively fixed.

[0079] A construction method for an underwater counterweight device for pipe jacking, the overall construction process is as follows: Figure 5 As shown, the construction method includes the following steps:

[0080] S1: Calculate the required size of airbag 2 based on the cross-section, dimensions, weight, hydrogeological conditions, length submerged in water, and weight of the pipe jacking machine head;

[0081] The volume of airbag 2 satisfies the following formula:

[0082] airbag 2 volume The force diagram of airbag 2 in water is shown below. Figure 6 As shown.

[0083] S2: Using manual installation, the airbag 2 is placed inside the jacking pipe 1 behind the jacking machine head, connecting the inflation / exhaust pipe 6 and the injection / drainage pipe 8. A construction diagram for this step is shown below. Figure 7 As shown.

[0084] S3: The inflation and water filling functions are normal. After the personnel evacuate the jacking pipe 1, the airbag 2 is filled with gas. The air pressure is maintained so that the airbag bulge 3 presses tightly against the inner wall of the jacking pipe 1, so that the anti-slip rubber 9 is in close contact with the inner wall of the jacking pipe 1.

[0085] The internal air pressure of airbag 2 satisfies the following formula:

[0086] air pressure The construction diagram for this step is as follows: Figure 8 As shown.

[0087] S4: Pipe jacking 1 is advanced until the jacking machine head emerges from the soil. Simultaneously, ballast water is injected into airbag 2 to displace the gas and maintain stable air pressure. Airbag 2 then begins to balance buoyancy. A construction diagram for this step is shown below. Figure 9 As shown.

[0088] S5: The jacking pipe 1 continues to advance to the designed position. During this process, the rate at which ballast water is injected into the airbag 2 to replace the gas is controlled according to the exposed length of the jacking pipe 1, maintaining stable air pressure and balancing the gradually increasing buoyancy. A construction diagram for this step is shown below. Figure 10 As shown.

[0089] The amount of water injected into airbag 2 satisfies the following formula:

[0090]

[0091] V 水 ≥0;

[0092] S6: Begin jacking head recovery, cutting the jacking pipe 1 behind the jacking head. Ambient water enters the interior of jacking pipe 1, reducing its buoyancy. Simultaneously, inflate airbag 2 to replace the ballast water, maintaining stable air pressure and balancing the gradually decreasing buoyancy. A construction diagram for this step is shown below. Figure 11 As shown.

[0093] The amount of water in airbag 2 satisfies the following formula:

[0094]

[0095] S7: After the pipe jacking machine head detaches, release the air pressure of airbag 2 to detach airbag 2 from the inner wall of pipe jacking 1. The construction diagram for this step is shown below. Figure 12 As shown.

[0096] S8: Airbag 2 floats naturally out of the jacking pipe 1 under the buoyancy of water, and airbag 2 is recovered. A construction diagram for this step is shown below. Figure 13 As shown.

[0097] During operation, the airbag 2 maintains stable internal pressure, and the air pressure can resist strong ambient water pressure. At the same time, it presses against the inner wall of the top pipe 1 to generate sufficient friction to resist ambient water pressure. Using the inflation and deflation pipe 6 and the injection and drainage pipe 8, the water volume of the airbag 2 is dynamically adjusted to meet the counterweight requirements while maintaining stable air pressure.

[0098] When cutting behind the jacking machine head, the buoyancy of the jacking pipe 1 decreases, and air is inflated into the airbag 2 to replace the ballast water in the airbag, maintaining stable air pressure and ensuring that the anti-slip rubber 9 is in close contact with the inner wall of the jacking pipe 1 to prevent the airbag 2 from sliding inside the jacking pipe 1.

[0099] After the airbag 2 has finished working, the air pressure can be released to allow the airbag 2 to detach from the inner wall of the jacking pipe 1, and it will naturally float out of the jacking pipe 1 under the buoyancy of the water, and the airbag 2 can be recovered.

[0100] In practical use, the invention ensures the anti-buoyancy requirements of the jacking pipe 1 construction while preventing slippage during counterweight anti-buoyancy. It allows for dynamic operation, and the counterweight weight can be adjusted at different stages of the jacking pipe 1 construction to meet different counterweight requirements. The operation is safe, and after the airbag 2 is installed, no personnel need to enter the jacking pipe to work, and it can be remotely controlled throughout the process.

Claims

1. A construction method for an underwater counterweight device for pipe jacking, the underwater counterweight device for pipe jacking includes an airbag (2), an airbag protrusion (3), and an airbag groove (4), the airbag (2) having the airbag protrusion (3) and the airbag groove (4) evenly and alternately distributed along the circumference, the airbag protrusion (3) being provided with anti-slip rubber (9), the upper part of the airbag (2) having an inflation / exhaust hole (5) and an inflation / exhaust pipe (6), through which the airbag can be filled, The compressed gas is released. The lower part of the airbag (2) is provided with injection and drainage holes (7) and injection and drainage pipes (8). Water can be injected and drained into the airbag through the injection and drainage holes (7) and injection and drainage pipes (8). The airbag (2) has a cylindrical structure when inflated, with both the front and rear ends bulging. The airbag (2) can fit tightly against the inner wall of the top tube (1) when inflated, and the anti-slip rubber (9) on the airbag protrusion (3) ensures that the position of the airbag (2) in the top tube (1) is relatively fixed. The characteristic is that... The construction method includes the following steps: S1: Calculate the required size of the airbag (2) based on the cross-section, size, weight, hydrogeological conditions, length submerged in water, and weight of the pipe jacking machine head; The volume of the airbag (2) satisfies the following formula: S2: The airbag (2) is placed in the jacking pipe (1) behind the jacking machine head by manual installation, and the inflation and deflation pipe (6) and the injection and drainage pipe (8) are connected. S3: Test the inflation and water filling functions to be normal. After the personnel leave the jacking pipe (1), fill the airbag (2) with gas and maintain the air pressure so that the airbag bulges (3) and presses against the inner wall of the jacking pipe (1) so that the anti-slip rubber (9) is in close contact with the inner wall of the jacking pipe (1). The internal air pressure of the airbag (2) satisfies the following formula: S4: The jacking pipe (1) is jacked until the jacking machine head is exposed from the soil. At the same time, ballast water is injected into the air bag (2) to replace the gas and maintain stable air pressure. The air bag (2) begins to balance the buoyancy. S5: The jacking pipe (1) is continuously jacked to the design position. During the process, the rate of ballast water injection into the airbag (2) to replace the gas is controlled according to the exposed length of the jacking pipe (1), so as to maintain stable air pressure and balance the gradually increasing buoyancy. The amount of water injected into the airbag (2) satisfies the following formula: V 水 ≥0； S6: Start the jacking head recovery, cut the jacking pipe (1) behind the jacking head, ambient water enters the jacking pipe (1), the buoyancy of the jacking pipe (1) decreases, at the same time, air is inflated into the airbag (2) to replace the ballast water in the airbag, maintain stable air pressure, and balance the gradually decreasing buoyancy; The amount of water in the airbag (2) satisfies the following formula: S7: After the jacking machine head is disengaged, release the air pressure of the airbag (2) so that the airbag (2) is disengaged from the inner wall of the jacking pipe (1); S8: The airbag (2) floats out of the top tube (1) naturally under the buoyancy of the water, and the airbag (2) is recovered.

2. The construction method of an underwater counterweight device for pipe jacking according to claim 1, characterized in that: During operation, the airbag (2) maintains stable internal pressure, and the air pressure can resist strong environmental water pressure. At the same time, it presses against the inner wall of the top tube (1) to generate sufficient friction to resist environmental water pressure.

3. The construction method of an underwater counterweight device for pipe jacking according to claim 1, characterized in that: During operation, the airbag (2) uses an inflation and deflation pipe (6) and an injection and drainage pipe (8) to dynamically adjust the water volume of the airbag (2) while maintaining stable air pressure, so as to meet the counterweight requirements.

4. The construction method of an underwater counterweight device for pipe jacking according to claim 1, characterized in that: When the jacking machine head is cut behind the jacking pipe, the buoyancy of the jacking pipe (1) is reduced, and air is injected into the airbag (2) to replace the ballast water in the airbag, maintain stable air pressure, and ensure that the anti-slip rubber (9) is in close contact with the inner wall of the jacking pipe (1) to prevent the airbag (2) from sliding inside the jacking pipe (1).

5. The construction method of an underwater counterweight device for pipe jacking according to claim 1, characterized in that: After the airbag (2) has finished working, the air pressure can be released to make the airbag (2) detach from the inner wall of the jacking pipe (1) and float out of the jacking pipe (1) naturally under the buoyancy of water, and the airbag (2) can be recovered.

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