Active supporting and leveling construction method for pipe joints of ultra-deep water immersed tunnel

Abstract

The invention discloses an ultra-deep water immersed tube tunnel tube joint active supporting and leveling construction method which comprises the following steps: before an immersed tube joint sinks, active supporting and leveling systems are symmetrically arranged at the vertex angle of the inner side of the immersed tube joint, a reserved pit hole is dug in a dry dock in advance to serve as an operation space for mounting a cushion block, and the immersed tube joint sinks after the cushion block is mounted; an active supporting and leveling system is used for automatically adjusting the posture of the immersed tube joint to a design value, mechanical operation and automatic control of the whole immersed tube installation process are achieved, manual diving operation is not needed, the construction efficiency and the installation precision are remarkably improved, meanwhile, cost and labor intensity are reduced, and then a permanent foundation is backfilled and constructed. The part, exceeding the bottom plate of the immersed tube section, of the active supporting and leveling system is removed, waterproof grease is replaced with waterproof mortar, and finally pressure bin concrete is laid on the bottom plate in the immersed tube tunnel, so that immersed tube installation is completed, the method is suitable for the water depth of more than 100 m, and the application range of post-laying method construction is expanded.

Description

Technical Field

[0001] This invention relates to the field of immersed tunnel installation and construction technology. More specifically, this invention relates to a method for active support and leveling of tunnel segments in ultra-deep water immersed tunnels. Background Technology

[0002] Immersed tunnels are an important method for constructing underwater passages across rivers and straits. The overall construction process involves prefabricating reinforced concrete sections in a dry dock on shore, then floating them to a designated area, immersing and docking them underwater to form a continuous underwater tunnel. This method offers significant advantages such as minimal impact on waterways, shallow burial depth, flexible cross-sectional layout, and short on-site operation time, making it one of the mainstream choices for constructing large underwater tunnels.

[0003] The installation of immersed tunnel sections is the most critical and technically complex part of the entire project, its core being to provide a uniform and reliable foundation support for the immersed tunnel segments. Depending on the construction sequence of the foundation treatment, there are two main construction techniques: the "pre-laying method" and the "post-laying method." The pre-laying method involves laying a carefully leveled layer of gravel or crushed stone at the bottom of the excavated trench before the tunnel segments are immersed, allowing them to rest directly on the foundation bed. The post-laying method uses the reverse process. Temporary supports (usually concrete blocks or small piles) are first installed at the four corners of the tunnel segments within the trench. Divers then install jacks above these temporary supports. After the tunnel segments are floated to their installation positions, they are immersed onto the jacks. The final elevation and longitudinal slope of the tunnel segments are precisely leveled by adjusting the jacks at the four corners. Finally, sand or mortar is filled into the gap between the bottom plate of the tunnel segment and the bottom of the trench, forming a permanent foundation. At this point, the jacks and temporary supports can be removed. The post-laying method has lower requirements for the absolute flatness of the bottom surface of the foundation trench compared to the pre-laying method, making it more adaptable and especially suitable for engineering scenarios with complex hydrogeological conditions or where large special-purpose vessels cannot be used.

[0004] In recent years, the number of long and deep immersed tunnels has gradually increased, greatly increasing the difficulty of immersed tunnel construction. The conventional diving operation limit is about 60m. For immersed tunnels with water depths exceeding 60m, the post-laying method will face the problem of underwater leveling being impossible. Therefore, there is an urgent need to develop a construction method for immersed tunnels under ultra-deep water conditions. Summary of the Invention

[0005] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0006] Another objective of this invention is to provide a method for active support and leveling of immersed tunnel segments in ultra-deep water, so as to solve the technical problem of difficulty in sinking and leveling of immersed tunnel segments under ultra-deep water conditions in the prior art.

[0007] To achieve these objectives and other advantages according to the present invention, a method for active support and leveling of ultra-deep water immersed tunnel segments is provided, comprising the following steps: S1. Before the prefabrication of the immersed tunnel segment, in the dry dock, according to the size of the immersed tunnel segment, pre-reserved pits are dug directly below the bottom of the four corners of the inner side of the immersed tunnel segment. The pre-reserved pits are backfilled with fine sand and compacted. During the prefabrication of the immersed tunnel, active support and leveling systems that can be vertically extended and retracted are arranged downward at the four corners of the inner side of the immersed tunnel segment. The active support and leveling systems pass downward through the corresponding position of the bottom plate of the immersed tunnel segment and form a section of annular cavity with vertical sealing between the bottom plate and the bottom plate. During this stage, the active support and leveling systems are kept in a retracted state and do not exceed the bottom of the immersed tunnel segment. S2. After the prefabrication of the immersed tube section is completed, the reserved pit is dug and the lower end of the active support leveling system extends into the reserved pit to install pads. S3. The immersed tunnel foundation trench is excavated to the predetermined depth; S4. Waterproof grease is injected into the annular cavity through a high-pressure injection pump until it is full. Then, the immersed tube section is floated to the top of the foundation trench to complete the outfitting. S5. Sink the pipe section. During the sinking process, continuously increase the grease injection pressure in the annular chamber and make the grease injection pressure slightly greater than the water pressure at the bottom of the pipe section to ensure the pipe section is sealed. Before the pipe section lands on the bed, reduce the sinking speed and accurately lower it until the pad falls on the foundation bed. S6. Measure the current elevation and longitudinal slope data of the immersed tunnel segment, compare them with the design values, automatically control each active support leveling system to adjust the extension length until the elevation and longitudinal slope data of the immersed tunnel segment reach the design values, and then lock the active support leveling system. S7. Lock backfilling is carried out on both sides of the width direction of the immersed tunnel section, and then non-segregating grout is filled into the gap between the bottom plate of the immersed tunnel section and the bottom surface of the foundation trench using grouting equipment to form a permanent foundation. S8. Remove the active support leveling system located above the bottom plate of the immersed tube section, inject waterproof mortar into the annular cavity under high pressure, squeeze out the waterproof grease in the annular cavity, and cut off the injection pipe after the waterproof mortar has solidified. S9. Pour ballast concrete inside the immersed tunnel section to complete the installation of the immersed tunnel section.

[0008] Preferably, in step S2, after the active support and leveling system extends downward to below the bottom of the immersed tunnel section, a lifting device is used to connect a pad block to the bottom of the active support and leveling system in a reserved pit, and the active support and leveling system is driven to retract, so that the pad block is close to the bottom plate of the immersed tunnel section, thus completing the pad block installation.

[0009] Preferably, the active support leveling system includes: Support brackets are fixed to the top of the four inner corners of the immersed tunnel section, with the lower end horizontal; The hydraulic jack has its base fixed to the bottom of the supporting bracket, and the piston rod of the hydraulic jack is set vertically downward. The outer sleeve is vertically embedded and fixed to the bottom plate of the immersed tube section. The bottom plate of the immersed tube section is vertically connected through the inner side of the outer sleeve. The inner side of the outer sleeve is vertically downward connected with rubber sealing rings and multiple layers of annular steel wire brushes, and the annular cavity is formed between adjacent layers of steel wire brushes. The upper end of the support rod is coaxially connected to the bottom of the piston rod via a flange, and the lower end is pressed downward along the coaxial direction and passes through multiple layers of steel wire brushes. The hydraulic jack can drive the support rod to move upward to the bottom plate position without exceeding the sinking pipe section. The injection pipe is fixed to the bottom plate of the submerged pipe section. One end of the injection pipe extends upwards out of the top of the bottom plate of the submerged pipe section to connect to the high-pressure injection pump, and the other end is connected to the annular chamber.

[0010] Preferably, the wire brush has four layers, forming three annular chambers between adjacent wire brushes, namely an upper chamber, a middle chamber, and a lower chamber. The injection pipe includes a first pipe, a second pipe, and a third pipe that are respectively fixed to the bottom plate of the submerged pipe section. The first pipe is connected to the upper chamber, the second pipe is connected to the middle chamber, and the third pipe is connected to the lower chamber.

[0011] Preferably, the system also includes an automated control system, which includes a remote control terminal that is interconnected with each other and a measuring tower arranged on top of the immersed tunnel segment. The measuring tower is used to acquire the elevation and longitudinal slope data of the immersed tunnel segment. The remote control terminal is interconnected with each of the active support and leveling systems and is used to store and set the design values ​​of the elevation and longitudinal slope data of the immersed tunnel segment and remotely control the automatic extension and retraction process of each of the active support and leveling systems.

[0012] Preferably, the reserved pit is 3-5m long and 1-2m wide.

[0013] Preferably, the pad is a reinforced concrete structure with a length and width ranging from 1 to 2 meters. The thickness of the pad is half the size of the reserved pit. A pre-embedded flange is provided on the top of the pad for connection with the lower end of the support rod.

[0014] The present invention has at least the following beneficial effects: (1) The active support and leveling construction method of the ultra-deep water immersed tunnel segment of the present invention adopts an active support and leveling system designed and developed independently. It is symmetrically arranged at the inner top corner of the immersed tunnel segment. When the immersed tunnel segment sinks and lands, the active support and leveling system is used to perform underwater leveling construction of the immersed tunnel segment, automatically adjusting the posture of the immersed tunnel segment to the design value, realizing mechanized operation and automated control of the entire process of immersed tunnel installation, significantly improving construction efficiency and installation accuracy. At the same time, there is no manual underwater diving operation, which improves the safety of immersed tunnel installation construction and reduces construction costs and labor intensity.

[0015] (2) The active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention involves installing an active support and leveling system at the inner top corner of the immersed tunnel section and passing through the bottom plate of the immersed tunnel section. Waterproof grease is injected between the active support and leveling system and the bottom plate of the immersed tunnel section for pressure control and sealing. After backfilling the permanent foundation, the part of the active support and leveling system above the bottom plate of the immersed tunnel section is removed, leaving the lower side and pad block part. Waterproof grease is replaced with waterproof mortar. Finally, pressure concrete is laid on the bottom plate inside the immersed tunnel to complete the installation of the immersed tunnel. This method significantly reduces the construction steps of installing and removing jacks in the existing technology, reduces the construction difficulty, and makes it easier to control pressure. It has low requirements for the flatness of the foundation bed and is applicable to water depths exceeding 100m, thus expanding the application scope of the post-laying method.

[0016] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0017] Figure 1 This is a structural schematic diagram of step S1 in the active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention. Figure 2 This is a structural schematic diagram of step S2 in the active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention. Figure 3 This is a schematic diagram of the active support and leveling system of the present invention installed on the bottom plate of the immersed tube section; Figure 4 This is a structural schematic diagram of step S5, sinking the immersed tunnel section, in the active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention. Figure 5 This is a schematic diagram of the structure of the extended pad block corresponding to step S5 in the active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention. Figure 6 This is a structural schematic diagram of step S6 in the active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention. Figure 7This is a structural schematic diagram of step S7, lateral backfilling, in the active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention. Figure 8 This is a structural schematic diagram of step S7, filling with non-segregating grout, in the active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention. Figure 9 This is a structural schematic diagram of step S8 in the active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention. Figure 10 This is a structural schematic diagram of step S9 in the active support and leveling construction method for ultra-deep water immersed tunnel sections of the present invention. Instruction manual drawing reference numerals: 1. Support bracket, 2. Hydraulic jack, 3. Flange, 4. Outer sleeve, 5. Rubber sealing ring, 6. First pipe, 7. Second pipe, 8. Third pipe, 9. Wire brush, 10. Upper chamber, 11. Middle chamber, 12. Lower chamber, 13. Support rod, 14. Embedded flange, 15. Pad, 16. Submerged pipe section, 17. Reserved pit, 18. Active support and leveling system, 19. Annular chamber, 20. Ballast concrete, 21. Permanent foundation, 22. Subgrade bed. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0019] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] like Figure 1-10 As shown, the present invention provides a method for active support and leveling construction of ultra-deep water immersed tunnel segments, comprising the following steps: S1. Before the prefabrication of the immersed tunnel section 16, in the dry dock, according to the size of the immersed tunnel section 16, pre-reserved pits 17 are dug directly below the bottom of the four inner corners of the immersed tunnel section 16. The pre-reserved pits 17 are backfilled with fine sand and compacted. During the prefabrication process, active support and leveling systems 18 that can extend and retract vertically are arranged downward at the four inner corners of the immersed tunnel section 16. The active support and leveling systems 18 pass downward through the corresponding position of the bottom plate of the immersed tunnel section 16 and are vertically sealed with the bottom plate to form a section of annular cavity 19. During this stage, the active support and leveling systems 18 are kept in a retracted state and do not exceed the bottom of the immersed tunnel section 16, so that the bottom of the immersed tunnel section 16 remains flat.

[0021] Each of the four corners is a set of active support leveling system 18, with a total of four active support leveling systems 18. Correspondingly, four reserved pits 17 are excavated. The main body of the active support leveling system 18 is a hydraulic leveler. Specifically, a reserved pit 17 with a length of 3-5m, a width of 1-2m, and a height of 1m is excavated in advance below the active support leveling system 18.

[0022] S2. After the prefabrication of the immersed tunnel section 16, the reserved pit 17 is excavated, and the lower end of the active support and leveling system 18 extends into the reserved pit 17. The pad block 15 is connected and installed at the lower end of the active support and leveling system 18. Then the lower end of the active support and leveling system 18 is pulled back a certain distance, and the pad block 15 is close to the bottom plate of the immersed tunnel section 16. The size of the pad block 15 is larger than the transverse cross-sectional size of the active support and leveling system 18.

[0023] Specifically, after the active support and leveling system 18 extends downward to below the bottom of the immersed tunnel section 16, a lifting device is used to connect the pad block 15 to the bottom of the active support and leveling system 18 in the reserved pit 17, and drive the active support and leveling system 18 to retract, so that the pad block 15 is close to the bottom plate of the immersed tunnel section 16, thus completing the installation of the pad block 15.

[0024] S3. The immersed tube foundation trench is excavated to the predetermined depth.

[0025] S4. Before the immersed tube is floated, waterproof grease is injected into the annular chamber 19 through a high-pressure injection pump and the chamber is filled. Waterproof grease is a paste-like sealing material with both lubricating and waterproofing functions. Then, the prefabricated immersed tube section 16 is floated to the top of the foundation trench, and equipment such as the measuring tower is installed to complete the secondary outfitting.

[0026] S5. By adjusting the ballast water system and cooperating with the sinking barge to sink the sinking pipe section 16, during the sinking process, the grease injection pressure of the annular chamber 19 is continuously increased and made slightly greater than the water pressure at the bottom of the sinking pipe section 16 to ensure the sealing of the sinking pipe section 16. Before the sinking pipe section 16 lands on the foundation bed, the sinking speed is reduced. When the bottom of the sinking pipe section 16 is 2m away from the foundation trench, the active support and leveling system 18 extends the pad 15 downwards at 0.5m, and the sinking pipe section 16 is then accurately and slowly lowered until the pad 15 lands on the foundation bed 22.

[0027] S6. Measure the current elevation and longitudinal slope data of the immersed tunnel section 16, compare it with the design value, and automatically control each active support leveling system 18 to adjust the extension length until the elevation and longitudinal slope data of the immersed tunnel section 16 reach the design value, and then lock the active support leveling system 18.

[0028] S7. Lock backfilling is carried out on both sides of the width direction of the immersed tube section 16. Then, non-segregating grout is filled into the gap between the bottom plate of the immersed tube section 16 and the bottom surface of the foundation trench using grouting equipment to form a permanent foundation 21. Then, other backfilling operations are carried out.

[0029] S8. Remove the active support leveling system 18 located above the bottom plate of the immersed tube section 16, inject waterproof mortar into the annular chamber 19 under high pressure, squeeze out the waterproof grease in the annular chamber 19, and cut off the injection pipe after the waterproof mortar solidifies.

[0030] S9. Pour 20 of ballast concrete into the immersed tunnel section 16 to complete the installation of the immersed tunnel section 16.

[0031] In this embodiment, the active support and leveling construction method for ultra-deep water immersed tunnel segments involves symmetrically arranging an active support and leveling system 18 at the inner apex corner of the immersed tunnel segment 16 before its sinking. The system passes through the bottom plate of the immersed tunnel segment 16. Waterproof grease is pressurized and injected between the active support and leveling system 18 and the bottom plate of the immersed tunnel segment 16 for pressure control and sealing. A pre-existing pit 17 is excavated in the dry dock to serve as the working space for installing the pads 15. After installing the pads 15, the immersed tunnel segment 16 is sunk. Upon landing, the active support and leveling system 18 automatically adjusts... The entire immersed tunnel segment 16 is aligned to the design value, achieving mechanized and automated operation and control of the entire immersed tunnel installation process. This eliminates the need for manual diving operations, significantly improving construction efficiency and installation accuracy while reducing costs and labor intensity. Afterward, the permanent foundation 21 is backfilled, and the active support and leveling system 18 is removed from the portion above the bottom plate of the immersed tunnel segment 16. Waterproof mortar is used to replace the waterproof grease, and finally, ballast concrete 20 is laid on the bottom plate inside the immersed tunnel to complete the immersed tunnel installation. This method is applicable to water depths exceeding 100m, expanding the application scope of the post-laying method.

[0032] In another technical solution, such as Figure 1-10As shown, the active support leveling system 18 includes: Support bracket 1 is fixed to the top of the four inner corners of the immersed tunnel section 16, that is, the top of the side wall of the immersed tunnel section 16, to ensure that the lower end is horizontal. The hydraulic jack 2 has its base fixed to the bottom of the supporting bracket 1, and the piston rod of the hydraulic jack 2 is set vertically downward. The outer sleeve 4 is vertically embedded and fixed on the bottom plate of the immersed tube section 16. The bottom plate of the immersed tube section 16 is vertically connected along the inner side of the outer sleeve 4. The inner side of the outer sleeve 4 is vertically fixed and connected with rubber sealing rings 5 ​​and multiple layers of annular steel wire brushes 9 in sequence. The annular chamber 19 is formed between adjacent layers of steel wire brushes 9. The upper end of the support rod 13 is coaxially connected to the bottom of the piston rod via the flange 3, and the lower end is pressed downward along the coaxial direction and passes through the multi-layer steel wire brush 9. The hydraulic jack 2 can drive the support rod 13 to move upward to the bottom plate position without exceeding the sinking pipe section 16. The injection pipe is fixed to the bottom plate of the submerged pipe section 16. One end of the injection pipe extends upwards out of the top of the bottom plate of the submerged pipe section 16 to connect to the high-pressure injection pump, and the other end is connected to the annular chamber 19.

[0033] The supporting bracket 1 is connected to the side wall of the immersed tube section 16, providing a support point for the hydraulic jack 2. The support rod 13 is a steel pipe about 1m long. The piston rod of the hydraulic jack 2 is connected to the support rod 13 through the flange 3. The outer sleeve 4 is a stainless steel cylinder, which is embedded in the bottom plate of the pipe section. The inner wall of the outer sleeve 4 is evenly distributed with multiple layers of annular steel wire brushes 9. The support rod 13 passes through the multiple layers of steel wire brushes 9, forming several annular chambers 19 between the support rod 13 and the outer sleeve 4. The annular chambers 19 are connected to the injection pipe. Waterproof grease or mortar is injected into the annular chambers 19 through a high-pressure injection pump. An annular rubber sealing ring 5 is set at the top of the outer sleeve 4 to further seal the gap between the support rod 13 and the outer sleeve 4. When the hydraulic jack 2 is working, the support rod 13 extends downward by 0.3~0.5m, and then the pad block 15 is installed. When the distance between the bottom of the pipe section and the foundation trench is 2m, the piston of the hydraulic jack 2 extends by 0.5m. By remotely driving the hydraulic jack 2 to extend and retract, the underwater submerged pipe section 16 is automatically leveled.

[0034] In another technical solution, such as Figure 1-10As shown, the wire brush 9 is provided with four layers, forming three annular chambers 19 between adjacent wire brushes 9, namely the upper chamber 10, the middle chamber 11, and the lower chamber 12. The injection pipe includes a first pipe 6, a second pipe 7, and a third pipe 8, which are respectively fixed to the bottom plate of the immersed tube section 16. The first pipe 6 is connected to the upper chamber 10, the second pipe 7 is connected to the middle chamber 11, and the third pipe 8 is connected to the lower chamber 12. Waterproof grease required for the sinking of the immersed tube section 16 or mortar required before pouring the pressure slab concrete 20 is injected into each chamber by a high-pressure injection pump. After the mortar solidifies, the first pipe 6, the second pipe 7, and the third pipe 8 are cut off.

[0035] In another technical solution, such as Figure 1-10 As shown, the system also includes an automated control system as a centralized control component. The automated control system includes a remote control terminal that is interconnected with each other and a measuring tower arranged on the top of the immersed tunnel section 16. The measuring tower is used to acquire the elevation and longitudinal slope data of the immersed tunnel section 16. The remote control terminal is connected to each of the active support and leveling systems 18 via wired or wireless communication. It is used to store and set the design values ​​of the elevation and longitudinal slope data of the immersed tunnel section 16 and remotely control the automatic extension and retraction process of each of the active support and leveling systems 18, adjusting the extension and retraction length of the support rod 13 respectively until the elevation and longitudinal slope data of the immersed tunnel reach the design values, and then locking the hydraulic jack 2.

[0036] In another technical solution, such as Figure 1-10 As shown, the pad 15 is a reinforced concrete structure with a length and width ranging from 1 to 2 meters. The thickness of the pad 15 is half that of the reserved pit 17. An embedded flange 14 is provided on the top of the pad 15 for connecting to the lower end of the support rod 13. In the horizontal direction, the reserved pit 17 is larger than twice the size of the pad 15, which facilitates the installation of the pad 15 outside the embedded pit on the outside of the submerged pipe section 16.

[0037] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for active support and leveling construction of ultra-deep water immersed tunnel segments, characterized in that, Includes the following steps: S1. Before the prefabrication of the immersed tunnel segment, in the dry dock, according to the size of the immersed tunnel segment, pre-reserved pits are dug directly below the bottom of the four corners of the inner side of the immersed tunnel segment. The pre-reserved pits are backfilled with fine sand and compacted. During the prefabrication of the immersed tunnel, active support and leveling systems that can be vertically extended and retracted are arranged downward at the four corners of the inner side of the immersed tunnel segment. The active support and leveling systems pass downward through the corresponding position of the bottom plate of the immersed tunnel segment and form a section of annular cavity with vertical sealing between the bottom plate and the bottom plate. During this stage, the active support and leveling systems are kept in a retracted state and do not exceed the bottom of the immersed tunnel segment. S2. After the prefabrication of the immersed tube section is completed, the reserved pit is dug and the lower end of the active support leveling system extends into the reserved pit to install pads. S3. The immersed tunnel foundation trench is excavated to the predetermined depth; S4. Waterproof grease is injected into the annular cavity through a high-pressure injection pump until it is full. Then, the immersed tube section is floated to the top of the foundation trench to complete the outfitting. S5. Sink the pipe section. During the sinking process, continuously increase the grease injection pressure in the annular chamber and make the grease injection pressure slightly greater than the water pressure at the bottom of the pipe section to ensure the pipe section is sealed. Before the pipe section lands on the bed, reduce the sinking speed and accurately lower it until the pad falls on the foundation bed. S6. Measure the current elevation and longitudinal slope data of the immersed tunnel segment, compare them with the design values, automatically control each active support leveling system to adjust the extension length until the elevation and longitudinal slope data of the immersed tunnel segment reach the design values, and then lock the active support leveling system. S7. Lock backfilling is carried out on both sides of the width direction of the immersed tunnel section, and then non-segregating grout is filled into the gap between the bottom plate of the immersed tunnel section and the bottom surface of the foundation trench using grouting equipment to form a permanent foundation. S8. Remove the active support leveling system located above the bottom plate of the immersed tube section, inject waterproof mortar into the annular cavity under high pressure, squeeze out the waterproof grease in the annular cavity, and cut off the injection pipe after the waterproof mortar has solidified. S9. Pour ballast concrete inside the immersed tunnel section to complete the installation of the immersed tunnel section.

2. The active support and leveling construction method for ultra-deep water immersed tunnel segments as described in claim 1, characterized in that, In step S2, after the active support and leveling system extends downward to below the bottom of the immersed tunnel section, a lifting device is used to connect a pad block to the bottom of the active support and leveling system in a reserved pit, and the active support and leveling system is driven to retract, so that the pad block is close to the bottom plate of the immersed tunnel section, thus completing the pad block installation.

3. The active support and leveling construction method for ultra-deep water immersed tunnel segments as described in claim 2, characterized in that, The active support leveling system includes: Support brackets are fixed to the top of the four inner corners of the immersed tunnel section, with the lower end horizontal; The hydraulic jack has its base fixed to the bottom of the supporting bracket, and the piston rod of the hydraulic jack is set vertically downward. The outer sleeve is vertically embedded and fixed to the bottom plate of the immersed tube section. The bottom plate of the immersed tube section is vertically connected through the inner side of the outer sleeve. The inner side of the outer sleeve is vertically downward connected with rubber sealing rings and multiple layers of annular steel wire brushes, and the annular cavity is formed between adjacent layers of steel wire brushes. The upper end of the support rod is coaxially connected to the bottom of the piston rod via a flange, and the lower end is pressed downward along the coaxial direction and passes through multiple layers of steel wire brushes. The hydraulic jack can drive the support rod to move upward to the bottom plate position without exceeding the sinking pipe section. The injection pipe is fixed to the bottom plate of the submerged pipe section. One end of the injection pipe extends upwards out of the top of the bottom plate of the submerged pipe section to connect to the high-pressure injection pump, and the other end is connected to the annular chamber.

4. The active support and leveling construction method for ultra-deep water immersed tunnel segments as described in claim 3, characterized in that, The wire brush has four layers, forming three annular chambers between adjacent wire brushes, namely an upper chamber, a middle chamber, and a lower chamber. The injection pipe includes a first pipe, a second pipe, and a third pipe that are respectively fixed to the bottom plate of the submerged pipe section. The first pipe is connected to the upper chamber, the second pipe is connected to the middle chamber, and the third pipe is connected to the lower chamber.

5. The active support and leveling construction method for ultra-deep water immersed tunnel segments as described in claim 3, characterized in that, The pad is a reinforced concrete structure with a length and width ranging from 1 to 2 meters. The thickness of the pad is half the size of the reserved pit. A pre-embedded flange is provided on the top of the pad for connection to the lower end of the support rod.

6. The active support and leveling construction method for ultra-deep water immersed tunnel segments as described in claim 1, characterized in that, It also includes setting up an automated control system, which includes a remote control terminal that is interconnected with each other and a measuring tower arranged on the top of the immersed tunnel segment. The measuring tower is used to acquire the elevation and longitudinal slope data of the immersed tunnel segment. The remote control terminal is interconnected with each of the active support and leveling systems and is used to store and set the design values ​​of the elevation and longitudinal slope data of the immersed tunnel segment and remotely control the automatic extension and retraction process of each of the active support and leveling systems.

7. The active support and leveling construction method for ultra-deep water immersed tunnel segments as described in claim 1, characterized in that, The reserved pit is 3-5m long and 1-2m wide.

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