Pipe sinking method for salt lake halogen extraction pipeline

Abstract

The present application relates to underwater pipeline construction technology field, concretely is a kind of salt lake takes brine pipeline sinking method, by making water head hoisting and installation work ship, after assembling pipe section on shore, pipe section is gradually installed in the rear of water head, when water head reaches the design water intake position, sinking pipe is carried out.This method can pull water head and water pipeline to specified position by the propeller driven by work ship, only need to lock down gravity anchor to lock ship when reaching specified position, it is suitable for small water depth, strong wind salt lake;Counterweight is used on pipeline to overcome salt lake buoyancy, speed up sinking pipe speed, counterweight is made of special mould, by concrete wrapping steel structure, it can effectively reduce the corrosion of steel structure, and after connecting counterweight, secondary grouting formwork can be wrapped with expansion concrete connecting bolt, further reduce corrosion.

Description

Technical Field

[0001] This invention relates to the field of underwater pipeline construction technology, specifically a method for submerging a brine extraction pipeline in a salt lake. Background Technology

[0002] Traditional inland lake water intake operations mainly involve welding the siphon pipes together on the water and then filling them with water before submerging them, or using large lifting vessels or towing ships to weld and submerge the pipes simultaneously on the water. The water-filling submerged method is heavy and difficult to adjust after the intake pipes are submerged; moreover, inland lakes lack large lifting vessels or towing ships, making the use of engineering vessels an impractical option.

[0003] Patent No. 107830244 discloses a novel method for installing water intake siphon pipes, specifically a submerged pipe method applicable to inland lakes. The above-water section construction comprises trench excavation, siphon pipe assembly, siphon head positioning and hoisting, underwater submerged pipe installation, backfilling, and the connection between the onshore and underwater pipe sections. This method solves problems related to underwater trench excavation, above-water pipe transportation, assembly of the operating platform, and submerged pipe by using self-made floating boxes. It also designs its own supports as hoisting and positioning tools for the water intake head, addressing the difficulties of above-water operations. However, salt lakes are mostly located in high-altitude plateau regions, and the salt lake water is corrosive, making pipe assembly in the water very difficult. Therefore, it is difficult to use floating boxes for pipe assembly in the water. Furthermore, due to the strong winds and high buoyancy of the salt lake water in the construction area, the existing water intake head installation vessels have poor stability, further increasing the construction difficulty. Summary of the Invention

[0004] Since existing construction methods have shortcomings, this invention proposes a method for submerging pipes for brine extraction from salt lakes.

[0005] The method for submerging brine extraction pipelines in salt lakes according to the present invention is characterized by the following steps:

[0006] 1) Construction of a workboat for lifting and installing the water intake head: The workboat consists of a hull, winch, generator, drive propeller, lifting frame, and gravity anchor; the hull consists of a floating tube, connecting plate, connecting frame, and bottom plate. One end of the connecting plate is provided with a semi-circular groove, which can be perpendicularly connected to the floating tube. A connecting plate is provided on each side of the connecting frame, and a bottom plate is provided on the connecting frame; a generator and drive propeller are provided at the stern of the hull; a winch is provided at the rear of the hull. A crane frame is installed in the middle of the hull. The crane frame consists of support columns, a crane beam, and diagonal bracing tubes. The crane beam is connected to the floating tube through the support columns. Diagonal bracing tubes are installed on both sides of the crane beam and are connected to the floating tube. Lifting lugs are installed at both ends and in the middle of the crane beam. There is a gravity anchor on each side of the hull. The gravity anchor is connected to the winch through steel cables. The steel cables are connected to the lifting lugs at both ends of the crane beam through hooks. The water intake head is suspended in the middle of the hull through the winch and steel cables in conjunction with the lifting lugs in the middle of the crane beam.

[0007] 2) Pipe section assembly: The prefabricated pipeline is assembled into several pipe sections on the shore of the salt lake, and counterweights are installed on each pipe section;

[0008] 3) Pipeline Assembly: The intake head and anchor are hoisted onto the workboat, ensuring that the intake inlet is above the water surface. One pipe section is hoisted to the water surface and connected to the intake head. Subsequent pipe sections are connected sequentially after the previous one. During the connection of each pipe section, the position of the workboat is gradually adjusted by driving the propeller, and the workboat is locked by gravity anchors to ensure that the pipeline composed of each pipe section is located at the designed pipeline coordinate position. At the end of the pipeline, a blocking plate is set on the shore, and an air vent valve is installed on the blocking plate to ensure that no water enters the pipeline section.

[0009] 4) Submerged pipe: As the water intake head is gradually moved to the designed water intake position, the water intake head and the anchor block are lowered by a winch. Water enters at one end of the water intake head of each pipe section and air is vented on the shore section. The sinking speed of the pipeline is indirectly controlled by the air venting valve, and the pipeline axis path is adjusted until the pipeline is completely located at the bottom of the designed trench on the lakebed.

[0010] After the immersed tunnel is completed, piers are set up on the shore, and the trench is backfilled according to the design and specifications.

[0011] Specifically, in step 2), the counterweight is made of a counterweight mold, including an inner mold, an outer mold, inner and outer mold clamping plates, and a secondary grouting template. The outer mold consists of an outer mold steel plate, an outer mold rib plate, and an outer mold clamping plate. The outer mold steel plate has outer mold rib plates on both sides and outer mold clamping plates at both ends. The inner mold consists of an inner mold steel plate, an inner mold rib plate, and an inner mold clamping plate. The inner mold steel plate has inner mold rib plates on both sides and inner mold clamping plates at both ends. The outer mold clamping plate, the connecting plates at both ends of the counterweight, and the inner mold clamping plate are connected by slots provided on the inner and outer mold clamping plates. The secondary grouting template consists of two secondary grouting side plates connected by a secondary grouting connecting plate. After the two counterweights are connected relative to each other, the secondary grouting template is set at the connection point.

[0012] Specifically, in step 4), the immersed tube is immersed in a distributed manner, which is as follows: slowly open the end vent valve, lower the winch, and make the water intake head sink 500mm. After the water intake head sinks into the water, water begins to enter the pipeline, and the gas pressure in the pipe gradually increases. When the gas pressure in the pipe reaches 0.2401Mpa, close the shore vent valve; slowly open the end vent valve again, and at the same time lower the winch, making the water intake head sink another 500mm, so that the pipeline slowly sinks into the water again; repeat this operation until the water intake head sinks to the bottom of the lake.

[0013] The present invention discloses a method for immersion pipe laying in salt lakes. A working vessel, driven by a propeller, can pull the intake head and intake pipe to a designated location. Once at the designated location, a gravity anchor is lowered to lock the vessel in place. This method is suitable for salt lakes with shallow water and strong winds. Counterweights are used on the pipeline to overcome buoyancy and accelerate the immersion process. These counterweights are made using special molds, and the steel structure is encased in concrete, effectively reducing corrosion. Furthermore, after the counterweights are connected, a secondary grouting template can encase the connecting bolts with expansive concrete, further reducing corrosion. This method effectively accelerates the immersion of salt lake brine extraction pipelines and ensures the quality of the immersion project, making it worthy of widespread application. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the working vessel of the present invention.

[0015] Figure 2 This is the AA cross-sectional view of the workboat.

[0016] Figure 3 This is a BB cross-sectional view of the workboat.

[0017] Figure 4 This is a CC cross-sectional view of the workboat.

[0018] Figure 5 This is a DD cross-sectional view of the workboat.

[0019] Figure 6 This is a schematic diagram of the counterweight mold of the present invention.

[0020] Figure 7 This is a schematic diagram of the outer mold structure.

[0021] Figure 8 This is a schematic diagram of the internal mold structure.

[0022] Figure 9 This is a schematic diagram of the secondary grouting template and secondary grouting structure.

[0023] Among them, 11: hull; 12: winch; 13: generator; 14: drive propeller; 15: lifting frame; 16: gravity anchor; 111: floating pipe; 112: connecting plate; 113: connecting frame; 114: bottom plate; 151: support column; 152: lifting beam; 153: diagonal brace pipe; 17: water intake head; 21: outer mold; 22: inner mold; 23: inner and outer mold clamping plate; 24: secondary grouting template; 25: PE pipe; 26: secondary grouting expansive concrete; 211: outer mold steel plate; 212: outer mold reinforcing plate; 213: outer mold clamping plate; 221: inner mold steel plate; 222: inner mold reinforcing plate; 223: inner mold clamping plate. Detailed Implementation

[0024] Example 1: This immersed tube method is used for brine extraction in a salt lake in Tibet. The implementation method is as follows: A working boat for hoisting and installing the intake head is constructed. The working boat consists of a hull, a winch, a generator, a drive propeller, a lifting frame, and a gravity anchor. The hull consists of a floating tube, connecting plates, a connecting frame, and a bottom plate. One end of the connecting plate is provided with a semi-circular groove, which allows for vertical connection to the floating tube. A connecting plate is provided on each side of the connecting frame, and a bottom plate is provided on the connecting frame. A generator and a drive propeller are provided at the stern of the hull. A winch is provided at the rear of the hull. A lifting frame is provided in the middle of the hull. The lifting frame consists of support columns, a lifting beam, and diagonal bracing tubes. The lifting beam is connected to the floating tube through the support columns. The lifting beam is equipped with diagonal bracing pipes on both sides, which are connected to the floating pipes. Lifting lugs are provided at both ends and in the middle of the lifting beam. A gravity anchor is provided on each side of the hull, and the gravity anchor is connected to the winch via steel cable. The steel cable is connected to the lifting lugs at both ends of the lifting beam via hooks. The water intake head is suspended in the middle of the hull via the winch and steel cable in conjunction with the lifting lugs in the middle of the lifting beam. The prefabricated pipes are assembled into several pipe sections on the shore of the salt lake. Each pipe section is equipped with a counterweight block. The counterweight block is made by a counterweight block mold, including an inner mold, an outer mold, inner and outer mold clamping plates, and a secondary grouting template. The outer mold consists of an outer mold steel plate, an outer mold reinforcing plate, and an outer mold clamping plate. The outer mold steel plate is provided with outer mold reinforcing plates on both sides and outer mold clamping plates at both ends. The inner mold consists of an inner mold steel plate, inner mold reinforcing plates, and inner mold clamping plates. Inner mold reinforcing plates are provided on both sides of the inner mold steel plate, and inner mold clamping plates are provided at both ends of the inner mold steel plate. The outer mold clamping plates, the connecting plates at both ends of the counterweights, and the inner mold clamping plates are connected by slots provided on the inner and outer mold clamping plates. The secondary grouting template consists of two secondary grouting side plates connected by a secondary grouting connecting plate. After the two counterweights are connected relative to each other, the secondary grouting template is placed at the connection point. The water intake head and the anchor block are installed and hoisted onto the workboat, ensuring that the water intake head inlet is above the water surface. One pipe section is hoisted to the water surface and connected to the water intake head. Subsequent pipe sections are connected sequentially after the previous pipe section. During the connection operation of each pipe section, the position of the workboat is gradually adjusted by driving the propeller. The workboat is secured using gravity anchors, ensuring that each pipeline segment is positioned at its designed coordinates. A blocking plate is placed at the pipeline's end on the shore, with an air vent valve installed on the blocking plate to prevent water from entering the pipeline segment. As the intake head gradually moves to the designed intake position, the end air vent valve is slowly opened, and the winch is lowered, causing the intake head to sink 500mm. Once submerged, water begins to enter the pipeline, and the gas pressure inside gradually increases. When the gas pressure reaches 0.2401 MPa, the shore air vent valve is closed. The end air vent valve is then slowly opened again, and the winch is lowered simultaneously, causing the intake head to sink another 500mm, allowing the pipeline to slowly sink again until it is completely submerged at the bottom of the designed trench on the lakebed. After the pipeline is submerged, piers are erected on the shore, and the trench is backfilled according to design and specification requirements. Once the entire pipeline construction is complete, all tooling and positioning equipment are removed, and the pipeline is dismantled and transported off-site.

Claims

1. A method for submerging pipelines for brine extraction from salt lakes, characterized in that... This will be implemented through the following steps: 1) Construction of a workboat for lifting and installing the water intake head: The workboat consists of a hull, winch, generator, drive propeller, lifting frame, and gravity anchor; the hull consists of a floating tube, connecting plate, connecting frame, and bottom plate. One end of the connecting plate is provided with a semi-circular groove, which allows it to be vertically connected to the floating tube. A connecting plate is provided on each side of the connecting frame, and a bottom plate is provided on the connecting frame; a generator and drive propeller are located at the stern of the hull; a winch is located at the rear of the hull. A crane frame is installed in the middle of the hull, consisting of support columns, a crane beam, and diagonal bracing tubes. The crane beam is connected to the floating tube through the support columns. Diagonal bracing tubes are installed on both sides of the crane beam and connected to the floating tube. Lifting lugs are installed at both ends and in the middle of the crane beam. A gravity anchor is installed on each side of the hull. The gravity anchor is connected to the winch through steel cables. The steel cables are connected to the lifting lugs at both ends of the crane beam through hooks. The water intake head is suspended in the middle of the hull through the winch and steel cables in conjunction with the lifting lugs in the middle of the crane beam. 2) Assemble pipe sections: Assemble the prefabricated pipes into several sections on the shore of the salt lake, with counterweights installed on each section; 3) Assemble the pipeline: Install and hoist the water intake head and anchor block onto the workboat, ensuring that the water intake head inlet is above the water surface. Hoist one pipe section to the water surface and connect it to the water intake head. Then, connect the pipe sections one after another after the previous pipe section. During the connection of each pipe section, the position of the workboat is gradually adjusted by driving the propeller, and the workboat is locked by gravity anchors to ensure that the pipeline composed of each pipe section is located at the designed pipeline coordinate position. At the end of the pipeline, a blocking plate is set on the shore, and an air vent valve is set on the blocking plate to ensure that no water enters the pipe section. 4) Submerged pipe: As the water intake head is gradually moved to the designed water intake position, the water intake head and the anchor block are lowered by a winch. Water enters at one end of the water intake head of each pipe section and air is vented on the shore section. The sinking speed of the pipeline is indirectly controlled by the air venting valve, and the pipeline axis path is adjusted until the pipeline is completely located at the bottom of the designed trench on the lakebed.

2. The method for submerging a brine extraction pipeline in a salt lake as described in claim 1, characterized in that... In step 2), the counterweight is made by a counterweight mold, including an inner mold, an outer mold, inner and outer mold clamping plates, and a secondary grouting template. The outer mold consists of an outer mold steel plate, an outer mold rib plate, and an outer mold clamping plate. The outer mold steel plate has outer mold rib plates on both sides and outer mold clamping plates at both ends. The inner mold consists of an inner mold steel plate, an inner mold rib plate, and an inner mold clamping plate. The inner mold steel plate has inner mold rib plates on both sides and inner mold clamping plates at both ends. The outer mold clamping plate, the connecting plates at both ends of the counterweight, and the inner mold clamping plate are connected by slots provided on the inner and outer mold clamping plates. The secondary grouting template consists of two secondary grouting side plates connected by a secondary grouting connecting plate. After the two counterweights are connected relative to each other, the secondary grouting template is set at the connection point.

3. The method for submerging a brine extraction pipeline in a salt lake as described in claim 1, characterized in that... In step 4), the submerged pipe adopts a distributed submerged pipe method, specifically: slowly open the end vent valve, lower the winch, and make the water intake head sink 500mm. After the water intake head sinks into the water, water begins to enter the pipeline, and the gas pressure in the pipe gradually increases. When the gas pressure in the pipe reaches 0.2401Mpa, close the shore vent valve; slowly open the end vent valve again, and at the same time lower the winch, making the water intake head sink another 500mm, so that the pipeline slowly sinks into the water again; repeat this operation until the water intake head sinks to the bottom of the lake.

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