A long-distance underwater transportation method for immersed tubes

Abstract

A long-distance underwater transportation method for immersed tubes, the steps of which are as follows: S1. After the prefabrication of the immersed tube segments is completed, preparations before launching are carried out; S2. Water is injected into the dry dock, and the immersed tube floats under the action of buoyancy to complete the launching of the immersed tube from the dock; S3. The towing barge tows the immersed tube and floats it along the waterway in the shallow sea area; S4. After the towing barge tows the immersed tube into the deep sea area, the immersed tube is towed to the installation position; S5. Before the immersed tube enters the installation position, the immersed tube floats up, and after floating up, the freeboard height is adjusted and the towing cable is adjusted; S6. The towing barge tows the immersed tube and floats it along the waterway to the designated installation position, and after basic positioning, mooring is carried out. By submerging the immersed tube segments for underwater transportation, the present invention avoids the damage to the structure caused by the extreme deep-sea environmental loads during the transportation process, realizes the long-distance transportation of the immersed tube across the deep sea area, and the present invention realizes the reuse of the existing immersed tube tunnel prefabrication factory, saving the investment in new projects and the construction period of the prefabrication yard.

Description

Technical Field

[0001] The present invention relates to the technical field of immersed tube transportation, and particularly to a long-distance underwater transportation method for immersed tubes. Background Art

[0002] With the successful construction of the immersed tube tunnel of the Hong Kong-Zhuhai-Macao Bridge, China has successively carried out the construction of immersed tube tunnels for the Dalian Bay Passage, the Shenzhen-Zhongshan Passage, and the Hanjiang Passage. Immersed tube tunnels have become one of the important channel forms for crossing deep water areas. The immersed tube segments of immersed tube tunnels are prefabricated in factories, which have the characteristics of high product quality, green economy, etc. However, it is difficult to select the location of the immersed tube prefabrication factory, and the one-time investment in site facilities construction and equipment purchase and installation is huge. It is unrealistic and uneconomical to configure a prefabrication factory for each immersed tube tunnel nearby. The site selection, dock construction, and configuration of automated production equipment all determine that the immersed tube tunnel prefabrication factory cannot be relocated or the relocation cost is huge. Reusing the existing immersed tube tunnel prefabrication factory to continue the production of immersed tube segments is beneficial to saving investment and construction period. However, the distance between the prefabrication factory and the location of the newly built immersed tube tunnel is often very far, reaching hundreds of kilometers. The transportation route will pass through deep sea areas, and the sea conditions in deep sea areas are more complex, with extreme waves, high winds and fast currents and other harsh conditions. There is an urgent need for a method that can transport immersed tubes over long distances under the complex sea conditions in the open sea. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a long-distance underwater transportation method for immersed tubes that can be applied to deep sea conditions.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A long-distance underwater transportation method for immersed tubes, the steps of which are as follows:

[0006] S1. After the prefabrication of the immersed tube segment is completed, preparations before launching are carried out. The end sealing doors are installed for watertightness tests to ensure that the immersed tube segment itself and the two end sealing doors are impermeable. Mooring posts and lifting points are installed on the top of the immersed tube. An attitude monitoring system is installed on the top of the immersed tube in a distributed manner. A buoyancy adjustment system is installed inside the immersed tube. An immersed tube tunnel docking and pulling device is installed for pulling and docking with the previous segment after the immersed tube sinks into place. After the tugboat has been overhauled, it is formed into a formation outside the dock and waits at anchor.

[0007] S2. Fill the dock with water. The immersed tube floats under the action of buoyancy. Adjust the freeboard height of the immersed tube through the buoyancy adjustment system to meet the requirements for leaving the dock and transportation in the shallow water channel. On both sides outside the dock entrance, set a turning column for guiding the towing cable to change direction. The towing cable is divided into two groups. One end of one group of towing cables is tied to the mooring post, and the other end is tied to the tugboat. One end of the other group of towing cables is tied to the mooring post, and the other end is tied to the winch on the shore after passing around the turning column. The winch and the tugboat jointly tow the immersed tube out of the dock. The tugboat is connected to the immersed tube in sequence according to the formation plan to complete the immersion tube leaving the dock;

[0008] S3. The tugboat tows the immersed tube and floats it along the channel in the shallow sea area. The maritime department's perimeter guard boats escort it in the front, back, and on both sides. The floating route is controlled by the maritime department according to the pre-approved channel to ensure the safety of the transportation line;

[0009] S4. After the tugboat tows the immersed tube into the deep sea area, to facilitate controlling the transportation attitude of the immersed tube and avoid damage to the immersed tube structure caused by extreme wave environmental loads, make the immersed tube submerge through the buoyancy adjustment system. The top surface of the immersed tube is below the sea level. After the immersed tube submerges in place, start deep-sea underwater towing and tow the immersed tube to the installation position;

[0010] S5. Before the immersed tube enters the installation position, the water depth gradually becomes shallower, and the sea surface wind and wave conditions meet the conditions for water towing. The immersed tube floats up. Control the floating attitude of the immersed tube through the buoyancy adjustment system and the tugboat. After the immersed tube floats up, adjust the freeboard height and the towing cable. The freeboard height is.m-.m, and the towing cable is adjusted to a position suitable for water towing;

[0011] S6. The tugboat tows the immersed tube and floats it along the channel to the designated installation position. After basic positioning, moor it. Submarine anchor posts for temporarily mooring the immersed tube and the transportation ship are pre-driven around the installation position, and wait for the window period to carry out the lowering operation of the immersed tube.

[0012] In the S1 step, the mooring post is the connection point between the tugboat and the immersed tube, and the lifting point is used for the installation ship to connect to the lifting point after the immersed tube is in place to lower the immersed tube.

[0013] The buoyancy adjustment system includes a ballast water tank and a pumping and drainage device. The buoyancy adjustment system adjusts the buoyancy of the immersed tube segment by injecting and draining water into the ballast water tank through the pumping and drainage device.

[0014] The attitude monitoring system consists of more than groups of liquid surface pressure gauges and a calculation and analysis system. By measuring the pressure at multiple points on the top of the immersed tube, calculate the water surface height at each point, the transverse inclination angle and the longitudinal inclination angle of the immersed tube, and monitor the transverse and longitudinal inclination postures of the immersed tube segment underwater to prevent the immersed tube from capsizing underwater.

[0015] In the S3 step, when floating and transporting in shallow waters, it is necessary to ensure that there is a sufficient safety distance between the bottom of the immersed tube and the seabed ground line to prevent bottom contact and reef hitting incidents.

[0016] In the S4 step, during the sinking process of the immersed tube, the buoyancy adjustment system gradually sinks by injecting seawater. Eventually, the total weight of the immersed tube is greater than the weight of the seawater it displaces, and the towing barge connected by the towing cable provides an upward pulling force to ensure that the immersed tube remains suspended in the water.

[0017] In the S4 step, during the sinking process of the immersed tube, the buoyancy adjustment system ensures that seawater is injected into each ballast tank synchronously, so that the immersed tube is evenly stressed in the horizontal plane, maintains a horizontal state, does not roll or tilt laterally, and at the same time uses the winch to release the cable of the towing barge, always keeping the cable in a taut state.

[0018] In the S4 step, the diving depth of the immersed tube is determined according to the water depth and wind and wave conditions of the transportation route. The depth of the top surface of the immersed tube below the sea level is greater than half of the extreme wave height to reduce the impact of waves on the attitude and structure of the immersed tube during deep-sea floating transportation. The bottom surface of the immersed tube is not less than one times the height of the immersed tube from the seabed bottom to prevent the immersed tube from touching the seabed and ensure transportation safety.

[0019] In the S5 step, the floating process of the immersed tube is the reverse process of diving. The buoyancy adjustment system evenly discharges the seawater in the ballast tank to make the immersed tube float horizontally. At the same time, the winch on the towing barge tightens the towing cable to keep the towing cable in a taut state to control the floating attitude of the immersed tube.

[0020] The beneficial effects of the present invention: The present invention avoids the damage to the structure caused by extreme deep-sea environmental loads during transportation by the method of submerging the immersed tube segments underwater for transportation, and realizes the long-distance transportation of the immersed tube across deep-sea areas. Compared with the method of transporting the immersed tube by a semi-submersible ship, the transportation method provided by the present invention can directly use the shipyard to float the immersed tube for launching, without the need to build a special semi-submersible ship outfitting deep-water area. The present invention realizes the reuse of the existing immersed tube tunnel prefabrication factory, saves the investment in new projects and the construction period of the prefabrication yard, conforms to the development concept of the national unified large market, avoids the repeated construction of prefabrication factories, and realizes the development of green economy. Brief Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the immersed tube leaving the dock and launching for the present invention.

[0022] Figure 2 It is a front view of the shallow-water floating transportation of the immersed tube for the present invention.

[0023] Figure 3 It is a top view of the shallow-water floating transportation of the immersed tube for the present invention.

[0024] Figure 4 It is a front view of the underwater towing of the immersed tube for the present invention.

[0025] Figure 5 This is the top view of the immersed tube during underwater towing for the present invention.

[0026] Figure 6 This is the front view of the immersed tube in place and moored for the present invention.

[0027] Figure 7 This is the top view of the immersed tube in place and moored for the present invention.

[0028] Wherein: 1 - immersed tube; 2 - docking and pulling device for immersed tube tunnel; 3 - attitude monitoring system; 4 - mooring post; 5 - towing cable; 6 - towing barge; 7 - steering post; 8 - dock; 9 - winch; 10 - seabed ground line; 11 - sea level line; 12 - buoyancy adjustment system; 13 - seabed anchor post. Specific implementation manner

[0029] A long - distance underwater transportation method for an immersed tube, the steps of which are as follows:

[0030] S1. After the pre - casting of one section of the immersed tube 1 is completed, preparations before launching are carried out. The end sealing doors are installed and a watertightness test is conducted to ensure that the immersed tube 1 section itself and the two end sealing doors are waterproof. Mooring posts 4 and lifting points are installed on the top of the immersed tube 1. The mooring post 4 is used as the connection point between the towing barge 6 and the immersed tube 1, and the lifting points are used for installing the ship connection lifting points after the immersed tube 1 is in place to lower the immersed tube 1. The attitude monitoring system 3 is distributed and installed on the top of the immersed tube 1. The attitude monitoring system 3 is composed of 4 or more groups of liquid - level pressure gauges and a calculation and analysis system. By measuring the pressure at multiple points on the top of the immersed tube 1, the water surface height at each point, the transverse tilt angle and the longitudinal tilt angle of the immersed tube 1 are calculated to monitor the transverse and longitudinal tilt postures of the immersed tube 1 section underwater and prevent the immersed tube 1 from capsizing underwater. The buoyancy adjustment system 12 is installed inside the immersed tube 1. The buoyancy adjustment system includes ballast tanks and a pumping and drainage device. The buoyancy adjustment system adjusts the buoyancy of the immersed tube 1 section by injecting and draining water into the ballast tanks through the pumping and drainage device. The docking and pulling device 2 for the immersed tube tunnel is installed, which is used for pulling and docking with the previous section after the immersed tube 1 sinks in place. After the towing barge 6 is overhauled, it is formed into a formation and in place outside the dock 8, and anchors are dropped and waiting;

[0031] S2. Water is injected into the dock 8, and the immersed tube 1 floats due to the buoyancy force. The freeboard height of the immersed tube 1 is adjusted through the buoyancy adjustment system 12 to meet the requirements for leaving the dock and transportation in the shallow water channel. On both sides outside the dock 8, a turning column 7 for guiding the towing cable 5 is provided at each side of the entrance. The towing cable 5 is divided into two groups. One end of one group of towing cables 5 is tied to the mooring post 4, and the other end is tied to the tow barge 6. The other group of towing cables 5 has one end tied to the mooring post 4 and the other end bypasses the turning column 7 and is tied to the winch 9 on the shore. One end of the towing cable 5 is tied to the mooring post 4, the other end is tied to the tow barge 6, and the other end bypasses the turning column 7 and is tied to the winch 9 on the shore. The winch 9 and the tow barge 6 jointly tow the immersed tube out of the dock 8. The tow barge 6 is connected to the immersed tube 1 in sequence according to the formation plan to complete the exit of the immersed tube 1 from the dock;

[0032] S3. The tow barge 6 tows the immersed tube 1 for floating transportation along the channel in the shallow sea area. The maritime department's outlying warning vessels provide escort in the front, rear, and on both sides. The floating transportation route is controlled by the maritime department according to the channel approved in advance to ensure the safety of the transportation line. When floating in the shallow sea area, it is necessary to ensure that there is enough safety distance between the bottom of the immersed tube 1 and the seabed ground line 10 to prevent grounding and reef hitting incidents;

[0033] S4. After the tow barge 6 tows the immersed tube 1 into the deep sea area, to facilitate controlling the transportation attitude of the immersed tube 1 and avoid damage to the structure of the immersed tube 1 caused by extreme wave environmental loads, the immersed tube 1 is submerged through the buoyancy adjustment system 12, and the top surface of the immersed tube 1 is below the sea level line 11. During the sinking process of the immersed tube 1, the buoyancy adjustment system 12 gradually sinks by injecting seawater. Eventually, the total weight of the immersed tube 1 is greater than the weight of the seawater it displaces, and the towing cable 5 connected to the tow barge 6 provides an upward pulling force to ensure that the immersed tube 1 remains suspended in the water. During the sinking process of the immersed tube 1, the buoyancy adjustment system 12 ensures that seawater is injected into each ballast tank synchronously, and the immersed tube 1 is evenly stressed in the horizontal plane, maintaining a horizontal state without rolling or tilting. At the same time, the towing cable 5 of the tow barge 6 is released using a winch, and the towing cable 5 is always kept in a tensioned state. The depth of the immersion of the immersed tube 1 is determined according to the water depth and wind and wave conditions of the transportation route. The depth of the top surface of the immersed tube 1 below the sea level line 12 is greater than half of the extreme wave height to reduce the influence of waves on the attitude and structure of the immersed tube 1 during deep sea floating transportation. The bottom surface of the immersed tube 1 is not less than one times the height of the immersed tube from the seabed bottom to prevent the immersed tube 1 from touching the seabed and ensure transportation safety. After the immersed tube 1 is submerged in place, deep sea underwater towing begins, and the immersed tube 1 is towed to the installation position;

[0034] S5. Before the immersed tube 1 enters the installation position, the water depth gradually becomes shallower, and the wind and wave conditions on the sea surface meet the conditions for water towing. The immersed tube floats up. The floating process of the immersed tube 1 is the reverse process of the submerged tube 1 diving. The seawater in the ballast water tank is evenly discharged through the buoyancy adjustment system 12 to make the immersed tube 1 float horizontally. At the same time, the winch on the towing barge 6 tightens the towing cable 5 to keep the towing cable 5 in a tensioned state to control the floating posture of the immersed tube 1. The floating posture of the immersed tube 1 is controlled by the buoyancy adjustment system 12 and the towing barge 6. After the immersed tube 1 floats up, the freeboard height and the towing cable are adjusted. The freeboard height is 0.15m-0.25m, and the towing cable is adjusted to a position suitable for water towing;

[0035] S6. The towing barge 6 tows the immersed tube 1 along the channel to the designated installation location, and mooring is performed after basic positioning. Seabed anchor columns 13 for temporary mooring of the immersed tube 1 and the transport vessel are pre-installed around the installation location, waiting for the window period for lowering the immersed tube 1.

[0036] Compared with semi-submersible vessels for transporting immersed tubes, the construction method provided by the present invention is not limited by the capacity of large-scale construction equipment. Existing tugboats can meet the towing requirements. The standard segment of the immersed tube tunnel weighs about 80,000 tons, and the existing largest semi-submersible vessel in the world has a weight of only 75,000 tons, which cannot meet the transportation needs of immersed tube segments, and the transportation cost is extremely high.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] In the present invention, unless otherwise clearly defined and limited, terms such as "installed", "connected", "linked", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The above has described the embodiments of the present invention in detail, but the above content is only the preferred embodiments of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the present invention application shall still fall within the scope covered by the patent of the present invention.

Claims

1. A long-distance underwater transportation method for immersed tubes, characterized in that, The steps are: S1. After the prefabrication of the immersed tube (1) segment is completed, the pre-launch preparation work is carried out. The end sealing doors are installed to conduct a watertightness test to ensure that the immersed tube (1) segment itself and the end sealing doors are watertight. The mooring posts (4) and the lifting points are installed on the top of the immersed tube (1). The attitude monitoring system (3) is installed on the top of the immersed tube (1). The buoyancy adjustment system (12) is installed inside the immersed tube (1). The immersed tube tunnel docking and pulling device (2) is installed to be used for pulling and docking the immersed tube (1) with the previous segment after it is sunk into place. After the towing barge (6) is inspected and repaired, it is positioned outside the dock (8) and anchored and waits. S2. The dock (8) is filled with water, and the submerged tube (1) floats due to the buoyancy. The freeboard height of the submerged tube (1) is adjusted by the buoyancy adjustment system (12) to meet the requirements of undocking and shallow waterway transportation. A steering column (7) for steering the towing cable (5) is provided on both sides of the doorway outside the dock (8). The towing cable (5) is divided into two groups. One end of the towing cable (5) of one group is tied to the mooring column (4) and the other end is tied to the towing barge (6). The other end of the towing cable (5) of the other group is tied to the mooring column (4) and the other end is tied to the winch (9) on the shore. The winch (9) and the towing barge (6) together tow the submerged tube out of the dock (8). The towing barge (6) is connected to the submerged tube (1) in sequence according to the formation plan, and the submerged tube (1) is undocking. S3. Towing barge (6) towing the submerged tube (1) in shallow waters along the waterway, escorted by maritime security vessels in front, behind and on both sides. The floating route is controlled by the maritime department in accordance with the waterway approved in advance to ensure the safety of the transportation route; S4. After the towing barge (6) tows the immersed tube (1) into the deep sea area, in order to facilitate the control of the transportation posture of the immersed tube (1) and to prevent the extreme wave environment load from causing damage to the structure of the immersed tube (1), the immersed tube (1) is submerged through the buoyancy adjustment system (12), and the top surface of the immersed tube (1) is submerged below the sea level (11). After the immersed tube (1) is submerged in place, deep-sea underwater towing begins to tow the immersed tube (1) to the installation position; S5. Before the submerged tube (1) enters the installation position, the water depth gradually becomes shallower, and the wind and wave conditions on the sea surface meet the conditions for water towing. The submerged tube floats up, and the floating posture of the submerged tube (1) is controlled by the buoyancy adjustment system (12) and the towing barge (6). After the submerged tube (1) floats up, the freeboard height and the towing cable are adjusted. The freeboard height is 0.15m-0.25m, and the towing cable is adjusted to a position suitable for water towing; S6. The towing barge (6) tows the immersed tube (1) along the waterway and floats it to the designated installation location. After basic positioning, it is moored. Seabed anchor posts (13) for temporary mooring of the immersed tube (1) and the transport vessel are pre-installed around the installation location, waiting for the window period to carry out the lowering operation of the immersed tube (1).

2. The long-distance underwater transportation method of the immersed tube according to claim 1, wherein In the step S1, the mooring bit (4) is used as the connection point between the towing barge (6) and the immersed tube (1), and the lifting point is used for the installation vessel to connect to the lifting point after the immersed tube (1) is in place to lower the immersed tube (1).

3. The long-distance underwater transportation method of the immersed tube according to claim 1, characterized in that, The described buoyancy adjustment system includes a ballast water tank and a pumping and drainage device. The buoyancy adjustment system adjusts the buoyancy of the immersed tube (1) segment by injecting and draining water from the ballast water tank through the pumping and drainage device.

4. The long-distance underwater transportation method of the immersed tube according to claim 1, characterized in that, The described attitude monitoring system (3) consists of 4 or more liquid surface pressure gauges and a calculation and analysis system. By measuring the pressure at multiple points on the top of the immersed tube (1), the water surface height at each point, the transverse inclination angle and longitudinal inclination angle of the immersed tube (1) are calculated to monitor the transverse and longitudinal inclination attitudes of the immersed tube (1) segment underwater and prevent the immersed tube (1) from capsizing underwater.

5. The long-distance underwater transportation method of the immersed tube according to claim 1, characterized in that, In the S3 step, when floating in shallow waters, it is necessary to ensure that there is a sufficient safety distance between the bottom of the immersed tube (1) and the seabed ground line (10) to prevent grounding and reef hitting incidents.

6. The long-distance underwater transportation method of the immersed tube according to claim 1, characterized in that, In the S4 step, during the sinking process of the immersed tube (1), the buoyancy adjustment system (12) gradually sinks by injecting seawater. Eventually, the total weight of the immersed tube (1) is greater than the weight of the seawater it displaces, and the towing barge (6) connected by the towing cable (5) provides an upward pulling force to ensure that the immersed tube (1) remains suspended in water.

7. The long-distance underwater transportation method of the immersed tube according to claim 6, characterized in that In the S4 step, during the sinking process of the immersed tube (1), the buoyancy adjustment system (12) ensures that seawater is injected into each ballast water tank synchronously, so that the immersed tube (1) is evenly stressed in the horizontal plane, remains in a horizontal state, does not undergo transverse inclination or side inclination. At the same time, the towing cable (5) of the towing barge (6) is released by the winch, and the towing cable (5) is always kept in a tensioned state.

8. The long-distance underwater transportation method of the immersed tube according to claim 7, characterized in that, In the S4 step, the diving depth of the immersed tube (1) is determined according to the water depth and wave and wind conditions of the transportation route. The top surface of the immersed tube (1) is submerged below the sea level line (11) by a depth greater than half of the extreme wave height to reduce the influence of waves on the attitude and structure of the immersed tube (1) during deep-sea floating transportation. The bottom surface of the immersed tube (1) is not less than one times the height of the immersed tube (1) from the seabed bottom to prevent the immersed tube (1) from touching the seabed and ensure transportation safety.

9. The long-distance underwater transportation method of the immersed tube according to claim 7, characterized in that, In the S5 step, the floating process of the immersed tube (1) is the reverse process of the diving process of the immersed tube (1). By evenly discharging the seawater in the ballast water tank through the buoyancy adjustment system (12), the immersed tube (1) floats horizontally. At the same time, the winch on the towing barge (6) tightens the towing cable (5) to keep the towing cable (5) in a tensioned state to control the floating attitude of the immersed tube (1).

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