Suction and silt squeezing device for seabed immersed tube foundation bed silt

Abstract

The utility model discloses a suction silt squeezing device for subsea immersed tube foundation bed silt, which comprises a plurality of silt suction heads, a silt suction pump, a plurality of silt blocking partition plates and a silt conveying hose, each silt suction head comprises a suction nozzle and a mounting head used for being connected with the silt conveying hose, and the suction nozzle of each silt suction head is a conical suction nozzle. The cone angle of the conical suction nozzle is determined according to the section shape of the foundation bed furrow, so that the mud suction head can be attached to the foundation bed furrow to be supported after being placed in the foundation bed furrow; the silt blocking partition plates are thin-wall rectangles with openings in the upper portions, the silt blocking partition plates are arranged at the positions, close to the boundaries of the immersed tubes, of the two sides of the seabed immersed tubes, the adjacent silt blocking partition plates are fixedly connected, and the silt blocking partition plates are used for preventing back silt from overflowing and have the silt containing effect. According to the utility model, the back-silting objects on the surface of the foundation can be cleaned under the condition that the foundation and the back-silting objects on the surface of the foundation are not disturbed, and the back-silting objects are prevented from falling back to the foundation again after desilting.

Description

Technical Field

[0001] This utility model belongs to the field of immersed tunnel construction technology, specifically relating to a device for suction and squeezing silt from the seabed immersed tunnel foundation. Background Technology

[0002] Currently, the main construction systems for immersed tunnel foundations include the pre-laying method and the post-laying method. The pre-laying method involves laying layers of crushed stone in alternating furrows within the excavated trench to form the foundation, followed by foundation leveling. The immersed tunnel sections are then laid after the foundation leveling is completed. Due to the time lag between foundation leveling and tunnel section laying, and the high sand content in some construction areas, the foundation surface can become covered with silt during this period. If the silt is not removed before laying the tunnel sections, it can lead to a series of safety problems, such as improper placement, excessive subsequent settlement, and stress and inclination exceeding safe limits. Existing methods to prevent excessive silt on the foundation surface from affecting the tunnel section laying mainly include: covering the foundation surface with geotextile to prevent silt from falling onto the foundation surface; using a suction dredger to clean the foundation surface; or placing a suction head on the foundation surface and using the suction force of the suction head to remove the silt as the suction dredger moves. The above methods have several drawbacks, including: the foundation may be disturbed during construction, affecting its stress characteristics; the construction process is cumbersome, delaying the construction period; the silt may be stirred up and fall back onto the foundation surface, resulting in poor dredging effect; and the pipe sections cannot be laid in time after dredging, causing the foundation surface to be covered with silt again when the pipe sections are laid. Utility Model Content

[0003] This utility model patent addresses the shortcomings of existing methods for removing silt from the foundation surface of submerged tunnels by proposing a suction and squeezing device for silt removal from the submerged tunnel foundation bed. This device utilizes a suction system to assist in silt removal from the bottom of the tunnel section during its placement. The technical solution is as follows:

[0004] A device for suction and squeezing silt from the submerged tunnel foundation bed includes several suction heads, a suction pump, several silt-blocking baffles, and a silt transport hose. Each suction head includes a suction nozzle and an mounting head for connecting the silt transport hose. The suction nozzle is conical, and the cone angle is determined according to the cross-sectional shape of the foundation trench, ensuring the suction head fits snugly against the trench for support. The silt-blocking baffles are thin-walled rectangles with openings at the top. They are positioned on both sides of the submerged tunnel, close to the tunnel boundary, and adjacent baffles are fixedly connected. The baffles prevent silt from overflowing and also serve to collect silt.

[0005] Furthermore, the suction head opening is equipped with an anti-clogging filter screen, and the diameter of the filter screen mesh is no larger than the diameter of the crushed stone in the crushed stone bed.

[0006] Furthermore, the length of the silt-blocking baffle is comparable to the length of the immersed tube section, forming a continuous protective barrier.

[0007] Furthermore, the height of the silt-blocking baffle is high enough to ensure that the top of the silt-blocking baffle is higher than the thickness of the backfill material after it is placed on the side of the immersed tube foundation. The width of the silt-blocking baffle is the same as the width of the area outside the immersed tube on the surface of the crushed stone foundation.

[0008] Furthermore, the axis of the suction head is parallel to the axis of the subgrade furrow, and its front end is located at the junction of the silt-blocking baffle and the submerged pipe.

[0009] The present invention relates to a device for pumping and squeezing back silt from the submerged tube foundation bed. This device utilizes the silt-squeezing load at the bottom of the submerged tube and a silt pump to simultaneously perform silt squeezing and suction work. It can clean the back silt from the foundation surface without disturbing the foundation and the back silt on the foundation surface, thus preventing the back silt from falling back onto the foundation after dredging and improving the dredging effect. Attached Figure Description

[0010] Figure 1 Schematic diagram of suction head

[0011] Figure 2 Schematic diagram of suction head

[0012] Figure 3 Schematic diagram of silt-blocking baffle

[0013] Figure 4 System cross-sectional diagram

[0014] Figure 5 Schematic diagram showing the locations of the silt-blocking baffle, sludge suction head, and sludge transport hose.

[0015] In the diagram, 1-sludge suction head; 2-installation head; 3-sludge transport hose; 4-silt-blocking baffle; 5-sludge suction pump; 6-submerged pipe; 7-gravel bed; 8-bed furrow; 9-foundation trench; 10-backfill material. Detailed Implementation

[0016] This invention provides a device for suction and squeezing silt from the submerged tunnel foundation bed, which can efficiently remove excessively thick silt from the foundation surface while avoiding disturbance to the foundation and the silt. A specific example is provided below, using the Hong Kong-Zhuhai-Macau Bridge foundation bed as an example for calculation. The width of the submerged tunnel is 37.95m, the width of the trench is 1.05m, the width of the platform is 1.8m, and the surface of the tunnel has a relatively thick layer of 0.2m of silt.

[0017] The present invention relates to a device for suction and squeezing silt from the submerged tunnel foundation bed, which mainly includes several suction heads 1, several silt-blocking baffles 4, a suction pump 5, and a silt transport hose 3.

[0018] like Figure 1 and 2As shown, this utility model designs and manufactures a mud suction head 1 according to the cross-sectional shape of the subgrade furrow. The mud suction head 1 includes a suction nozzle and an installation head 2 for connecting the mud transport hose 3. The suction nozzle of the mud suction head 1 is a conical suction nozzle. The size of the cone angle of the conical suction nozzle is determined according to the cross-sectional shape of the subgrade furrow, so that the mud suction head 1 fits into the furrow after being placed in the furrow to obtain support. The height of the mud suction head 1 should be 5cm lower than the height of the subgrade furrow. The opening of the mud suction head 1 is provided with an anti-clogging filter screen. The diameter of the filter screen mesh is not greater than the diameter of the crushed stone in the crushed stone subgrade.

[0019] like Figure 3 and 4 As shown, the suction and silt removal device of this utility model also includes several silt-blocking baffles 4. The silt-blocking baffles 4 are thin-walled rectangles with openings at the top. The silt-blocking baffles 4 are placed on both sides of the immersed tube close to the boundary of the immersed tube. Adjacent silt-blocking baffles 4 are fixedly connected. The placement length of the silt-blocking baffles 4 is equivalent to the length of the immersed tube section, forming a continuous protective barrier. The height of the silt-blocking baffles 4 is high enough to ensure that the top of the silt-blocking baffles 4 is higher than the thickness of the silt after being placed on the side of the immersed tube foundation.

[0020] The width of the silt-retaining baffle is the same as the width of the area outside the submerged pipe on the surface of the crushed stone subgrade. The axis of the suction head is parallel to the axis of the subgrade furrow, and its front end is located at the junction of the silt-retaining baffle and the submerged pipe.

[0021] The construction method is as follows:

[0022] 1) Conduct site surveys and measurements, using ground-penetrating radar or borehole sampling to determine the depth, width, and silt thickness distribution characteristics of the foundation trenches. Based on the length and width of the submerged pipe, plan the length and installation position of the silt-blocking baffle 4 and the layout path of the suction head 1.

[0023] 2) Design and manufacture the suction head 1 according to the cross-sectional shape of the subgrade furrow. The suction head 1 includes a suction nozzle and an installation head 2 for connecting the mud transport hose 3. The suction nozzle of the suction head 1 is a conical suction nozzle, so that the suction head 1 fits into the furrow after being placed in the furrow to obtain support. The height of the suction head 1 is 5cm lower than the height of the subgrade furrow. The opening of the suction head 1 is provided with an anti-clogging filter screen. The diameter of the filter screen mesh is not greater than the diameter of the crushed stone in the crushed stone subgrade.

[0024] 3) Fabricate a silt-blocking baffle 4, wherein the silt-blocking baffle 4 is a thin-walled rectangle with an opening at the top, and is made of steel plate or polymer composite material plate;

[0025] 4) Equipment debugging and material preparation, check the water tightness of the silt-blocking baffle 4, sludge suction head 1, and sludge transport hose 3.

[0026] 5) After the gravel bed leveling is completed, install the silt-retaining baffles 4. Immediately after foundation leveling, place the silt-retaining baffles 4 symmetrically along both sides of the bed furrows, ensuring that the top of the silt-retaining baffles 4 is higher than the thickness of the backfill material. Place the silt-retaining baffles 4 on the foundation surface close to the boundary of the submerged pipe. The width of the silt-retaining baffles 4 is the same as the width of the area outside the submerged pipe on the gravel bed surface, and the length of the silt-retaining baffles 4 is equivalent to the length of the pipe section, forming a continuous retaining barrier. Connect adjacent silt-retaining baffles 4 with bolts or clips to form a continuous and closed retaining structure to prevent backfill material from overflowing. Simultaneously, during the subsequent sedimentation process, the backfill material can be deposited within the U-shaped silt-retaining baffles 4, serving as a sediment trap.

[0027] 6) Deploy the suction head 1 and place it in the furrow at the bottom of the silt-blocking baffle 4. Ensure that the bottom of the suction head 1 is in contact with the silt bed furrow to obtain support, and make the silt-blocking baffle 4, the sinking pipe, the silt bed and the suction head 1 form a closed space to efficiently carry out the silt squeezing and suction operation.

[0028] 7) Connect the mud transport hose 3 to the mud suction pump 5, ensuring that the connection between the mud transport hose 3 and the mud suction pump 5 will not detach during operation. The mud transport hose 3 should be located outside the construction area. One end of the mud transport hose 3 is connected to the mounting head 2 of the suction head 1 under the silt-blocking baffle 4, and the other end is connected to the suction pump 5 on the water surface. During the silt removal process of the submerged pipe, the returned silt is transported from underwater to the water surface. The mud transport hose 3 should be made of pressure-resistant and wear-resistant material to adapt to the bending requirements of complex terrain. The suction pump 5 is located above the water surface, providing stable negative pressure to drive the returned silt to be sucked out from the bottom of the submerged pipe and transported to the water surface through the mud transport hose 3. The mud transport hose 3 and the mounting head 2 are connected by a diver underwater installation method. Ensure that the connection between the mud transport hose 3 and the circular mounting head 2 will not detach during operation. During the silt removal process of the submerged pipe, the suction head 1 uses negative pressure to suck the returned silt into the mud transport hose 3.

[0029] 8) Begin the sinking of the tunnel sections. Ensure the accuracy of the sinking of the tunnel sections and avoid the tunnel sections squeezing against the silt-blocking baffle 4.

[0030] 9) While the immersed tube section is being lowered, start the sludge pump 5 to remove the silt from the bottom of the immersed tube. Observe the state of the material sucked out by the sludge pump 5. When there is almost no silt in the material sucked out, stop the sludge suction operation.

Claims

1. A device for suction and squeezing silt from a submerged tunnel foundation bed, comprising a plurality of suction heads (1), a suction pump (5), and a silt transport hose (3), wherein each suction head (1) includes a suction nozzle and an mounting head (2) for connecting to the silt transport hose (3), characterized in that, The suction nozzle of the suction head (1) is a conical suction nozzle. The cone angle of the conical suction nozzle is determined according to the cross-sectional shape of the ridge of the subgrade, so that the suction head (1) can fit into the ridge of the subgrade after being placed to obtain support. The suction and silt removal device also includes several silt-blocking baffles (4). The silt-blocking baffles (4) are thin-walled rectangles with openings at the top. The silt-blocking baffles (4) are placed on both sides of the submerged tube close to the boundary of the submerged tube. Adjacent silt-blocking baffles (4) are fixedly connected. The silt-blocking baffles (4) are used to prevent the backfill material from overflowing and have the function of collecting silt.

2. The suction and squeezing device for silt removal from the submerged tunnel foundation bed according to claim 1, characterized in that, The suction head opening is equipped with an anti-clogging filter screen, and the diameter of the filter screen mesh is no larger than the diameter of the crushed stone in the crushed stone bed.

3. The device for suction and squeezing silt from the submerged tunnel foundation bed according to claim 1, characterized in that, The length of the silt-blocking baffle is equivalent to the length of the immersed tube section, forming a continuous protective barrier.

4. The suction and squeezing device for silt removal from the submerged tunnel foundation bed according to claim 1, characterized in that, The height of the silt-blocking baffle is high enough to ensure that the top of the silt-blocking baffle is higher than the thickness of the backfill material after it is placed on the side of the immersed tube foundation. The width of the silt-blocking baffle is the same as the width of the area outside the immersed tube on the surface of the crushed stone foundation.

5. The suction and squeezing device for silt removal from the submerged tunnel foundation bed according to claim 1, characterized in that, The axis of the suction head is parallel to the axis of the ditch in the subgrade, and its front end is located at the junction of the silt-blocking baffle and the submerged pipe.

6. The device for suction and squeezing silt from the submerged tunnel foundation bed according to claim 1, characterized in that, The suction head is placed in the trench of the subgrade near the bottom of the silt-blocking baffle, and the silt-blocking baffle, the sinking pipe, the subgrade and the suction head form a closed space.

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