A method for combined dredging and gas lifting in a shield tunnel repair project

Abstract

The application relates to a kind of gas lift combined dredging methods of shield tunnel repair engineering, at least two through holes communicated with shield tunnel are punched and set on shield tunnel, water and airflow are injected into the inside of shield tunnel at one of the through hole positions, water and airflow impact the deposited silt in the inside of shield tunnel and form a slurry mixture, gas lift reverse circulation dredging equipment is lowered at another through hole position, a large amount of high-speed gas is injected into the slurry discharge pipeline of gas lift reverse circulation dredging equipment, the slurry mixture is discharged through the slurry discharge pipeline by using the density difference between the gas-liquid mixture in the pipeline and the slurry mixture in the shield tunnel, clean water is injected into the shield tunnel through the water injection pipe, the dynamic balance of water intake and discharge is realized, and the silt replacement in the shield tunnel is carried out. The application has the advantages that: a large range of dredging can be realized in the deep buried space in the bottom of shield tunnel by adjusting the middle high-pressure jet grouting and the parameters of gas lift at both ends under the limited equipment lowering and walking space.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel repair engineering technology, and in particular to a method for air-lift combined dredging in shield tunnel repair engineering, especially a method for dredging mud and sand inside shield tunnels with large burial depths and different clearance opening intervals. Background Technology

[0002] Water seepage and collapse accidents occasionally occur during shield tunnel construction. Currently, the commonly used repair method requires filling and sealing specific tunnel sections. However, before filling, a large amount of silt may accumulate inside the tunnel, which greatly affects the quality of the filling.

[0003] After an accident, the existing tunnel will be connected to an external aquifer, and the entire section will typically be filled with water, making dredging work difficult. Currently, there is no mature dredging method specifically for the repair of shield tunnel sections.

[0004] Existing air-lift lifting devices are mostly used for resource extraction at the bottom of rivers, lakes and seas or for hole cleaning construction of cast-in-place piles and diaphragm walls. In these operation scenarios, the underground space and the surface are completely connected, and the movement of the dredging device is unrestricted.

[0005] For underground shield tunnels, it is obviously impossible to achieve full coverage of the dredging area by using the limited number of boreholes to lower traditional air-lift dredging devices. In other words, existing dredging devices cannot achieve large-scale dredging effects within the limited space available for equipment placement. However, the residual silt will bring uncontrollable risks to the subsequent construction of the shield tunnel section repair. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art by providing a combined air-lift dredging method for shield tunnel repair projects. By adjusting the water and air pressure of the high-pressure jet dredging system and the position and orientation of the hose below the air-lift reverse circulation dredging equipment according to the hole spacing above the tunnel, the dredging requirements under conditions of large hole spacing can be met, enabling large-scale dredging of underground spaces under the condition of fixed-point equipment placement.

[0007] The objective of this invention is achieved through the following technical solutions:

[0008] A method for combined air-lift and dredging in shield tunnel repair projects, characterized by the following steps:

[0009] At least two through holes are drilled in the shield tunnel to connect with its interior;

[0010] Water and airflow are injected into the shield tunnel at one of the through-hole locations, causing the water and airflow to impact the deposited silt inside the shield tunnel and form a mud-water mixture;

[0011] A gas-lift reverse circulation sludge removal device is placed at another through-hole location. A large amount of high-speed gas is injected into the mud discharge pipe of the gas-lift reverse circulation sludge removal device. The density difference between the gas-liquid mixture in the pipe and the mud-water mixture in the shield tunnel is used to discharge the mud-water mixture from the shield tunnel through the mud discharge pipe.

[0012] Clean water is injected into the shield tunnel through a water injection pipe to achieve a dynamic balance between water intake and drainage, thereby replacing the silt inside the shield tunnel.

[0013] By adjusting the pressure of the water and airflow, a larger area of ​​silt can be agitated.

[0014] The injection of water and air is achieved by arranging a high-pressure jet grouting machine at the through hole location. The water and air jetting machine agitates the sediment at the bottom of the shield tunnel, causing the sediment to mix with the water and become suspended.

[0015] The air-lift reverse circulation dredging equipment includes a mud discharge pipe and a retractable hose installed at the bottom of the mud discharge pipe. The retractable hose is connected to the mud discharge pipe, and its bottom end is a mud inlet. The dredging range can be adjusted by adjusting the position and orientation of the mud inlet at the bottom end of the retractable hose.

[0016] An upper sliding limit box and a lower sliding limit box are installed on the mud discharge pipe. A linkage mechanism is provided between the upper sliding limit box and the lower sliding limit box. One end of the linkage mechanism extends out of the ground and the other end is connected to the retractable hose. The lower sliding limit box is connected to a wire. By stretching the wire, the lower sliding limit box is driven to rotate relative to the upper sliding limit box, and the retractable hose is driven to extend and rotate through the linkage mechanism.

[0017] The upper sliding limit box is provided with an upper sliding module, which can slide on the upper limit box shell of the upper sliding limit box; the lower sliding limit box is provided with a lower sliding module, which can slide on the lower limit box shell of the lower sliding limit box.

[0018] The linkage mechanism includes an upper linkage, a first lower linkage, and a second lower linkage. One end of the upper linkage extends out of the ground, and the other end is connected to the upper sliding module. One end of the first lower linkage is connected to the upper sliding module, and the other end is connected to the lower sliding module. One end of the second lower linkage is connected to the lower sliding module, and the other end is connected to the retractable hose.

[0019] An air supply elbow is welded onto the mud discharge pipe. One end of the air supply elbow is connected to the interior of the mud discharge pipe, and the other end of the air supply elbow is connected to a high-pressure air supply hose.

[0020] The water injection pipe is positioned at the through-hole where the water and air are injected.

[0021] The sludge discharge pipe of the air-lift reverse circulation sludge removal equipment discharges the sludge-water mixture into a three-stage sedimentation tank located on the ground.

[0022] Through holes are drilled on both sides of the through holes for water and air injection, and the air-lift reverse circulation sludge removal equipment is lowered down.

[0023] The advantages of this invention are: it can achieve large-scale dredging of the deep buried space at the bottom of the shield tunnel by adjusting the parameters of the high-pressure jet grouting in the middle and the air lift at both ends, even with limited equipment placement and travel space; it can achieve large-scale dredging of underground spaces with different burial depths and different equipment placement distances; it is convenient to construct and suitable for widespread application. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the arrangement structure of the present invention;

[0025] Figure 2 This is a diagram showing the initial state construction of the present invention;

[0026] Figure 3 This is a structural diagram of the present invention in the case of large-scale dredging.

[0027] Figure 4 This is a plan view and a side view of the upper sliding limiting box in this invention;

[0028] Figure 5 This is a three-dimensional structural diagram of the lower sliding limiting box in this invention. Detailed Implementation

[0029] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art:

[0030] like Figure 1-5 As shown in the figure, each of the markings represents: 1. High-pressure jet grouting machine, 2. Water injection pipe, 3. Air-lift sludge removal device, 4. High-pressure airflow delivery hose, 5. High-pressure air pump, and 6. Three-stage sedimentation tank.

[0031] 31. Mud discharge pipe; 32. Air supply elbow; 33. Wire; 34. Wire limit ring; 35. Upper sliding limit box; 36. Lower sliding limit box; 37. Connecting rod limit ring; 38. Telescopic hose.

[0032] Upper limit box housing 351, upper sliding module 352, upper connecting rod 353, first lower connecting rod 354;

[0033] The components include: lower limit box housing 361, lower sliding module 362, second lower connecting rod 364, sliding bearing 365, fixing nut 366, sliding bearing 367, fixing nut 368, and protruding rod 312.

[0034] Example: The air-lift combined dredging method for shield tunnel repair engineering in this example is used to dredge the mud and water (silt) that have flowed into the shield tunnel after a water seepage accident.

[0035] like Figure 1 As shown, the dredging method in this embodiment includes the following steps:

[0036] 1) Holes are drilled from the ground towards the shield tunnel, creating through-holes that connect the ground to the interior of the shield tunnel. The spacing of the holes is generally determined based on the dredging area. In this embodiment... Figure 1 In the shield tunnel, three through holes are opened.

[0037] 2) A high-pressure rotary jet grouting machine 1 is installed at the middle through hole position. The nozzle of the high-pressure rotary jet grouting machine 1 is located in the shield tunnel. It stirs up the silt in the shield tunnel, especially the sediment at the bottom of the shield tunnel, by spraying high-pressure water and air. This causes the silt and water in a large area at the bottom to mix and become suspended.

[0038] 2) Air-lift sludge removal devices 3 are installed at the two through-hole positions on both sides. These air-lift sludge removal devices 3 are used to remove the mud-water mixture. Specifically, a high-pressure air pump 5 injects a large amount of high-speed gas into the pipeline through a high-pressure airflow delivery hose 4. The density difference between the gas-liquid mixture in the pipeline and the mud-water mixture in the tunnel is used to carry the mud-water mixture out of the shield tunnel.

[0039] 3) Simultaneously, clean water is supplied into the tunnel through water injection pipe 2 to achieve a dynamic balance between water intake and drainage, displacing the silt and sand within the tunnel, thereby achieving the purpose of dredging. The function of balancing water intake and drainage is as follows: if the drainage volume exceeds the jet grouting water intake volume, silt from both sides of the shield tunnel may continuously flow into the dredging area. In this case, a fixed amount of clean water can be injected into the tunnel through water injection pipe 2 to maintain the balance between water intake and drainage. At the same time, when the injected clean water has a certain pressure, it will also agitate the silt in the shield tunnel to a certain extent. In conjunction with the high-pressure jet grouting pile machine 1, it can achieve silt agitation over a large area.

[0040] 4) The discharged mud-water mixture is transported to the three-stage sedimentation tank 6 for sedimentation and separation, and then further treatment is carried out.

[0041] like Figure 1As shown, conventional air-lift dredging devices are lowered from fixed-point holes drilled in the shield tunnel. Therefore, the dredging effect is limited to the projection range of the fixed-point holes. When the spacing between the holes in the upper part of the shield tunnel is large (i.e., the horizontal distance between the high-pressure jet grouting machine 1 and the air-lift dredging device 3 is large), due to the limited range of conventional air-lift dredging, some silt cannot be completely removed. Therefore, it cannot meet the requirements for large-scale dredging, often resulting in silt remaining inside the shield tunnel, which brings uncontrollable risks to the subsequent construction of the shield section repair.

[0042] To address the problem of incomplete sludge removal, this embodiment provides two measures that can be used alone or in combination to expand the impact range of air-lift dredging, thereby achieving adaptive dredging for different opening spacings in deeply buried tunnels. Specifically:

[0043] 1) By increasing the pressure of water and air in the high-pressure jet grouting machine 1, a larger area of ​​silt can be agitated. The principle is that as the pressure of water and air is increased, the spraying range is correspondingly increased, and the agitation force on the thicker silt is also relatively greater, so that it can be agitated from its original viscous state to a suspended state to increase its fluidity, which is convenient for cooperation with the air-lift dredging device 3 to achieve dredging.

[0044] 2) By setting an adjustable telescopic hose at the bottom of the air-lift dredging device 3, the mud inlet of the air-lift dredging device 3 can be adjusted, thereby expanding the range of air-lift dredging and improving the dredging effect.

[0045] Both of the above methods can improve the dredging effect when used alone; however, when the two are used in combination, the water and air pressure injected by the high-pressure jet grouting machine 1 is greater, which will cause a directional flow with a certain flow velocity to form in the mud-water mixture. This directional flow is also directed towards both sides of the air-lift dredging device 3, thus significantly improving the mud discharge effect and efficiency.

[0046] In this embodiment, the air-lift sludge removal device 3 can be used through... Figures 2 to 5 The structure shown is implemented. The main body of the air-lift dredging device 3 is a mud discharge pipe 31, which is hollow inside as a discharge channel for mud and sand. An air supply elbow 32 is welded to the mud discharge pipe 31. One end of the air supply elbow 32 extends into the interior of the mud discharge pipe 31 to form a communication with it, and the other end is connected to a high-pressure air supply hose 4 to supply air to the high-pressure air pump 5.

[0047] An upper sliding limit box 35 and a lower sliding limit box 36 are fixedly installed along the height direction on the surface of the mud discharge pipe 31, while a retractable hose 38 is installed at the bottom of the mud discharge pipe 31. The retractable hose 38 is hollow inside and communicates with the mud discharge pipe 31, with its bottom opening serving as a mud inlet. In this embodiment, the retractable hose 38 is retractable and rotatable. Figures 2 to 3 The shape transformation shown allows for adjustment of the mud inlet position at the bottom of the retractable hose 38, thereby expanding the airlift dredging range and improving the dredging effect. In this embodiment, the upper sliding limit box 35 and the lower sliding limit box 36 are mainly used to control the extension and rotation of the retractable hose 38.

[0048] Specifically, combined Figures 3 to 5 As shown, the upper sliding limit box 35 includes an upper limit box housing 351, which is fixed to the surface of the mud discharge pipe 31 and has a slide rail inside that matches the upper sliding module 352. The lower part of the upper sliding module 352 is embedded in the upper limit box housing 351 and can slide along the slide rail provided inside it. Figure 4 In the indicated direction, the upper sliding module 352 slides up and down along the slide rail of the upper limit box housing 351. The upper sliding module 352 connects the bottom end of the upper connecting rod 353 and the top end of the first lower connecting rod 354. The upper connecting rod 353 and the first lower connecting rod 354 are respectively sleeved on the surface protrusion of the upper sliding module 352 by sliding bearings and fixed by fixing nuts. The top end of the upper connecting rod 353 extends out of the ground. When the upper connecting rod 353 is pushed downward, it can drive the upper sliding module 352 and the first lower connecting rod 354 to move downward.

[0049] The lower sliding limit box 36 includes a lower limit box housing 361. The top of the lower limit box housing 361 is connected to a protruding rod 312 welded to the outer surface of the mud discharge pipe 31 via a sliding bearing 365 and a fixing nut 366. The sliding bearing 365 is installed between the lower limit box housing 361 and the protruding rod 312 to facilitate the rotation of the lower sliding limit box 36 around the protruding rod 312, while the fixing nut 366 is used to prevent the lower sliding limit box 36 from coming out. A slidable lower sliding module 362 is also provided on the lower limit box housing 361. The lower sliding module 362 connects the bottom end of the first lower connecting rod 354 and the top end of the second lower connecting rod 364. The first and second lower connecting rods 354 and 364 are also connected to the lower sliding module 362 using sliding bearings 367 and fixing nuts 368. The sliding bearings 367 facilitate rotation of the first and second lower connecting rods 354 and 364 around the lower sliding module 362, while the fixing nuts 368 prevent the first and second lower connecting rods 354 and 364 from disengaging. The bottom end of the second lower connecting rod 364 is fixedly connected to the retractable hose 38.

[0050] like Figure 2 and Figure 3 As shown, a wire 33 is also installed on the mud discharge pipe 31. The top end of the wire 33 is above the ground, and its bottom end is connected to the protruding rods extending from both sides of the bottom of the lower sliding limit box 36. Thus, the rotation of the lower sliding limit box 36 can be adjusted by pulling the wire 33 on the ground, and its rotation direction can be further controlled.

[0051] Combination Figures 2 to 5 As shown, when using the air-lift combined dredging device in this embodiment, the upper connecting rod 353 is pushed downwards, and the wire 33 is pulled. At this time, the upper sliding module 352 slides downwards and simultaneously drives the first lower connecting rod 354 connected to it to move downwards. During the downward movement, the first lower connecting rod 354 is affected by the rotation pair between it and the second lower connecting rod 364, causing the lower sliding module 362 to slide downwards and drive the lower sliding limit box 36 to rotate around the protruding rod 312. At the same time, the second lower connecting rod 364 itself also rotates to a certain extent. Since the retractable hose 38 is connected to the second lower connecting rod 364, the retractable hose 38 is stretched and rotated under the drive of the second lower connecting rod 364, thereby adjusting the position of its end opening, i.e., the position of the mud inlet, and thus achieving the effect of expanding the air-lift dredging influence range.

[0052] contrast Figure 2 and Figure 3 As shown, when in Figure 2 In the state shown, the impact range of airlift dredging is limited to the vertical range of the mud discharge pipe 31; however, when in the state shown... Figure 3 In the state shown, because the telescopic hose 38 has extended and rotated, its orientation after rotation exceeds the vertical range of the mud discharge pipe 31. This extended range is the expanded airlift dredging influence range.

[0053] like Figure 2 and Figure 3 As shown in the illustration, the retractable hose 38 in this embodiment is intended to rotate clockwise. In this case, sufficient force should be applied to the rightmost wire of the two wires 33 to cause the lower sliding limit box 36 to rotate counter-clockwise from its vertical position. Conversely, if it is necessary to rotate the retractable hose 38 counter-clockwise, sufficient force should be applied to the leftmost wire to cause the lower sliding limit box 36 to rotate clockwise from its vertical position, thereby causing the retractable hose 38 to rotate counter-clockwise.

[0054] In the specific implementation of this embodiment: as follows Figure 2As shown, multiple wire limiting rings 34 are welded at intervals on the outer surface of the mud discharge pipe 31 corresponding to the extension direction of the wire 33 to limit the wire 33 and ensure the pulling effect. The wire 33 is connected to the protruding rods extending from the bottom of the lower sliding limiting box 36 after passing through the corresponding wire limiting rings 34 on the side.

[0055] A connecting rod limiting ring 37 is welded at the bottom of the mud discharge pipe 31. The position of the connecting rod limiting ring 37 corresponds to the position of the second lower connecting rod 364 and covers the rotation range of the second lower connecting rod 364. That is, the rotation range of the second lower connecting rod 364 is limited by the connecting rod limiting ring 37 to ensure rotation accuracy.

[0056] Although the above embodiments have described the concept and embodiments of the present invention in detail with reference to the accompanying drawings, those skilled in the art will recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, and therefore will not be elaborated here.

Claims

1. A method for combined air-lift and dredging in shield tunnel repair projects, characterized in that: Includes the following steps: At least two through holes are drilled in the shield tunnel to connect with its interior; Water and airflow are injected into the shield tunnel at one of the through-hole locations, causing the water and airflow to impact the deposited silt inside the shield tunnel and form a mud-water mixture; A gas-lift reverse circulation sludge removal device is placed at another through-hole location. A large amount of high-speed gas is injected into the mud discharge pipe of the gas-lift reverse circulation sludge removal device. The density difference between the gas-liquid mixture in the pipe and the mud-water mixture in the shield tunnel is used to discharge the mud-water mixture from the shield tunnel through the mud discharge pipe. Clean water is injected into the shield tunnel through a water injection pipe to achieve a dynamic balance between water intake and drainage, thereby replacing the silt inside the shield tunnel.

2. The air-lift combined dredging method for shield tunnel repair engineering according to claim 1, characterized in that: By adjusting the pressure of the water and airflow, a larger area of ​​silt can be agitated.

3. A method for combined air-lift and dredging in shield tunnel repair engineering according to claim 1 or 2, characterized in that: The injection of water and air is achieved by arranging a high-pressure jet grouting machine at the through hole location. The water and air jetting machine agitates the sediment at the bottom of the shield tunnel, causing the sediment to mix with the water and become suspended.

4. The air-lift combined dredging method for shield tunnel repair engineering according to claim 1, characterized in that: The air-lift reverse circulation dredging equipment includes a mud discharge pipe and a retractable hose installed at the bottom of the mud discharge pipe. The retractable hose is connected to the mud discharge pipe, and its bottom end is a mud inlet. The dredging range can be adjusted by adjusting the position and orientation of the mud inlet at the bottom end of the retractable hose.

5. The air-lift combined dredging method for shield tunnel repair engineering according to claim 4, characterized in that: An upper sliding limit box and a lower sliding limit box are installed on the mud discharge pipe. A linkage mechanism is provided between the upper sliding limit box and the lower sliding limit box. One end of the linkage mechanism extends out of the ground and the other end is connected to the retractable hose. The lower sliding limit box is connected to a wire. By stretching the wire, the lower sliding limit box is driven to rotate relative to the upper sliding limit box, and the retractable hose is driven to extend and rotate through the linkage mechanism.

6. The air-lift combined dredging method for shield tunnel repair engineering according to claim 5, characterized in that: The upper sliding limit box is provided with an upper sliding module, which can slide on the upper limit box shell of the upper sliding limit box; the lower sliding limit box is provided with a lower sliding module, which can slide on the lower limit box shell of the lower sliding limit box. The linkage mechanism includes an upper linkage, a first lower linkage, and a second lower linkage. One end of the upper linkage extends out of the ground, and the other end is connected to the upper sliding module. One end of the first lower linkage is connected to the upper sliding module, and the other end is connected to the lower sliding module. One end of the second lower linkage is connected to the lower sliding module, and the other end is connected to the retractable hose.

7. The air-lift combined dredging method for shield tunnel repair engineering according to claim 4, characterized in that: An air supply elbow is welded onto the mud discharge pipe. One end of the air supply elbow is connected to the interior of the mud discharge pipe, and the other end of the air supply elbow is connected to a high-pressure air supply hose.

8. The air-lift combined dredging method for shield tunnel repair engineering according to claim 1, characterized in that: The water injection pipe is positioned at the through-hole where the water and air are injected.

9. The air-lift combined dredging method for shield tunnel repair engineering according to claim 1, characterized in that: The sludge discharge pipe of the air-lift reverse circulation sludge removal equipment discharges the sludge-water mixture into a three-stage sedimentation tank located on the ground.

10. The air-lift combined dredging method for shield tunnel repair engineering according to claim 1, characterized in that: Through holes are drilled on both sides of the through holes for water and air injection, and the air-lift reverse circulation sludge removal equipment is lowered down.

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