An underwater immersed tube system and method of construction thereof

Abstract

The application discloses an underwater immersed tube system, which comprises an assembled immersed tube, an adjusting pipe base, a water intake head, a cross beam, a vertical pile and a half, the base of the water intake head is fixed by pouring underwater concrete with a steel mold frame, the cross beam is arranged on the vertical pile through a pile cap, a pair of adjusting pipe bases are arranged on the cross beam, the top surface of the adjusting pipe base is an arc surface, the immersed tube is arranged on the pair of adjusting pipe bases, a clamp is arranged on the immersed tube, the two ends of the clamp are connected to the cross beam to fix the immersed tube, the immersed tubes are connected through the half, the middle part of the half is arched upwards to form a drum-shaped half, and the half is divided into an upper half and a lower half. The underwater immersed tube system changes the integral pile cap and cross beam structure into assembled components, reduces the labor intensity of the underwater operation of divers, improves the butt joint precision, and guarantees the installation quality of the pile cap and the cross beam.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of immersed tube, in particular to an underwater immersed tube system and a construction method thereof. BACKGROUND

[0002] The water intake system of power plants, waterworks and the like usually adopts a self-flowing water intake mode, and the water intake enters through the upper inlet window of the water intake head, and then flows out from the bottom outlet pipe, passes through the immersed tube section and the top pipe section, and enters the front pool of the pump house.

[0003] With the continuous increase of the water intake scale, the diameters and single-piece weights of the top pipe, the water intake head and the immersed tube are becoming larger and larger. During underwater operation, due to the action of water buoyancy and resistance, the diver's operation is clumsy, the labor intensity is high, the action is slow, the positioning control difficulty increases sharply, and it becomes a major technical problem. SUMMARY

[0004] In view of the above technical deficiencies, the purpose of the present application is to provide an underwater immersed tube system and a construction method thereof, which solves the problem of high labor intensity and difficult installation of the existing immersed tube as a whole.

[0005] To solve the above technical problems, the present application adopts the following technical scheme:

[0006] The present application provides an underwater immersed tube system, which comprises an assembled immersed tube, an adjusting pipe seat, a water intake head, a cross beam, a standing pile and a haf. The base of the water intake head is fixed by pouring underwater concrete with a steel mold frame. The cross beam is arranged on the standing pile through a pile cap. A pair of adjusting pipe seats are arranged on the cross beam. The top surface of the adjusting pipe seat is arc-shaped. The immersed tube is placed on the pair of adjusting pipe seats. A clamp is arranged on the immersed tube. The two ends of the clamp are connected to the cross beam to fix the immersed tube. The immersed tubes are connected through the haf. The middle part of the haf is arched upward to form a drum-shaped haf. The haf is divided into an upper haf and a lower haf. The upper haf and the lower haf are connected through bolts.

[0007] Preferably, a pipe-shaped rubber ring is arranged between the haf and the immersed tube.

[0008] Preferably, the pipe-shaped rubber ring is fixed by steel bars.

[0009] Preferably, a plurality of bolt holes are arranged on the haf.

[0010] Preferably, the haf is wrapped with a mold bag cloth.

[0011] The present application also relates to a construction method of an underwater immersed tube system, which comprises the following specific steps:

[0012] S1, making three-dimensional simulation model of immersed tube According to the same scale, make the three-dimensional simulation model of immersed tube, use the model pipe segment to arrange the lifting point for trial lifting, review and determine the balance posture of immersed tube after lifting, so that the immersed tube does not twist after lifting;

[0013] According to the model, the sequence of underwater operation of divers, the operation space, the installation alignment control, the fastening requirement of fixed parts, and the safety protection measures are explained and introduced intuitively;

[0014] S2, excavation of immersed tube foundation trench: import the foundation trench plan into the GPS satellite positioning system software of the grab bucket dredger, excavate the soil with the grab bucket dredger, and throw the soil to the specified deep region of the maritime department by the open type barge;

[0015] According to the design safety and stable slope ratio, correct the deviation at any time to avoid over-excavation and under-excavation, and appropriately leave a margin during the excavation process to meet the space requirement of underwater operation of divers;

[0016] S3, steel pipe pile setting: the GPS of the pile driver first preliminarily positions, then feeds the pile, checks the perpendicularity, simultaneously measures the accurate position by intersection of the total station and the theodolite, sets the steel pipe pile after the positioning is completed, and finally controls the elevation of the top of the steel pipe pile by the level;

[0017] S4, installation of water head: install the lower half of the connecting pipe on the ground, set the mark rod on the top of the water head higher than the water surface, adjust the water head to be flat after lifting, self-propel the floating crane, preliminarily position by the GPS, accurately control the axis of the mark rod by the total station and the theodolite, check and compare by the divers underwater, and the position deviation of the two-way axis is not more than ±50mm;

[0018] S5, installation of pile cap, cross beam and adjusting pipe base: when installing the two pile caps of the cross beam, the direction of the top connecting steel plate needs to be controlled on a straight line and perpendicular to the axis of the immersed tube; temporarily fix the left and right adjusting pipe bases on the cross beam before lifting the cross beam, and the size between the left and right adjusting pipe bases is 200mm-300mm larger than the size on the installation drawing;

[0019] When lifting the cross beam, set up the theodolite on the ground to control the position of the axis, and command the divers to move the cross beam underwater so that the cross hair of the theodolite and the lifting hook plumb line of the cross beam coincide; after the cross beam is in place, the pile cap and the cross beam are connected and fixed by bolts, and the double nuts are tightened;

[0020] S7, installation of immersed tube, half and clamp:

[0021] 1) calibrate the screw hole of the half by trial assembly, install the pipe type rubber ring, and mark the assembled upper half and lower half clearly with paint;

[0022] 2) when connecting and fixing the lower half with the end of the immersed tube, the bolt hole position should be set to prevent water seepage;

[0023] 3) The sinking pipe is hoisted by a 500-ton floating crane, and three independent hooks are needed;

[0024] 4) The three lifting points on the sinking pipe should use separate hooks to facilitate adjustment of the sinking pipe posture;

[0025] 5) After lifting off the ground, adjust the pipe axis, height difference and three-dimensional model posture to keep consistent;

[0026] 6) The floating crane is self-propelled, and GPS is used for preliminary positioning;

[0027] 7) Two theodolites are installed on the ground to control the two-axis lines;

[0028] 8) Pulling ropes are arranged at both ends of the sinking pipe to pull and adjust the pipe to match the axis direction;

[0029] 9) When the sinking pipe is sunk to a distance of 500mm from the designed elevation, the diver checks the pipe port connection, confirms the correctness, and then places the sinking pipe on the cross beam;

[0030] 10) The diver moves left and right to adjust the pipe seat one by one, so that it is completely attached to the pipe body and the bolts are tightened, and then the lifting steel cable is removed;

[0031] 11) Install the upper half and the clamp;

[0032] S7, the length and width of the mold bag cloth are greater than the size of the half; the four edges of the mold bag cloth are provided with nylon ropes in advance, two steel pipes with a diameter of 50mm are used to guide the sinking of the mold bag cloth into the water and hang on both sides of the half, the diver removes the steel management along the mold bag cloth, and then tightens all the nylon ropes;

[0033] S8, when pouring underwater concrete in the steel mold frame of the water intake base, the concrete guide pipe should always be inserted into the concrete, the guide pipe should be continuously and slowly moved, the insertion and pouring elevation of the guide pipe is controlled by the diver; after the underwater construction work is completed, the water intake head, sinking pipe and shore slope are backfilled for protection.

[0034] Preferably, in S8, the protective measures usually taken include laying geotextile soft body, throwing and filling gravel, throwing and filling bagged soil, and throwing and filling block stone.

[0035] The beneficial effects of the present application are:

[0036] 1. Establish a visual information model

[0037] According to the construction drawings, a three-dimensional sinking pipe visual information model is drawn by using BIM technology, the number and size of parts are accurately calculated, and the safety technology disclosure of part processing and underwater operation essentials is intuitively made to the operating personnel, so that the pre-planning and preparation are more intuitive and close to the actual situation, and the safety and quality assurance capability is improved.

[0038] 2. Underwater trench excavation

[0039] The grab dredger with GPS positioning system is accurate, convenient, effectively prevents under-digging and over-digging, greatly improves work efficiency and reduces cost.

[0040] 3. Measurement control

[0041] The plane control adopts the ground intersection method of total station and theodolite to accurately control the positioning of pile sinking, pipe sinking and water intake head, and the elevation control adopts the leveling instrument to control the pile top elevation, so as to ensure the underwater installation accuracy of the parts.

[0042] 4. Optimization of pile cap and cross beam

[0043] The integral pile cap and cross beam structure is changed into an assembled part, which reduces the labor intensity of the diver's underwater operation, improves the butt joint accuracy, and effectively ensures the installation quality of the pile cap and cross beam.

[0044] 5. Optimization of adjusting pipe seat and clamp

[0045] The adjusting pipe seat and the sinking pipe are separately manufactured, and an independent clamp is added, which solves the problems of large splicing site, high platform erection requirement and difficult pipe opening space butt joint of the integral manufacturing of the adjusting pipe seat and the sinking pipe.

[0046] 6. Optimization of half

[0047] The drum-type half is used to replace the original design paper flat half, which eliminates the difficulty of pipe connection caused by the small gap and axis deviation between the pipes, and improves the quality of the pipe butt joint.

[0048] 7. Increase of anti-seepage of the mold bag cloth

[0049] The mold bag cloth completely wraps the half, which further improves the tightness of the half joint to prevent seepage.

[0050] 8. Wide application range

[0051] It is suitable for underwater sinking pipe construction of all water intake projects of power plants, waterworks and the like, including straight sinking pipe, inclined sinking pipe and underwater butt joint installation of three-dimensional space change sinking pipe. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0053] Figure 1 A structure schematic diagram of an underwater sinking pipe system provided by the embodiment of the present application.

[0054] Figure 2 This is a schematic diagram of the structure of an adjustment pipe seat for an underwater submerged pipe system provided in an embodiment of the present invention;

[0055] Figure 3 A schematic diagram of the structure of a half-submerged pipe system provided in an embodiment of the present invention;

[0056] Figure 4 A flowchart illustrating a construction method for an underwater immersed pipe system provided in an embodiment of the present invention.

[0057] Explanation of reference numerals in the attached diagram: 1. No. 1 immersed tube; 2. No. 2 immersed tube; 3. No. 3 immersed tube; 4. No. 4 immersed tube; 5. No. 5 immersed tube; 6. No. 6 immersed tube; 7. No. 7 immersed tube; 8. Lower half-frame; 9. Upper half-frame; 10. Underwater concrete; 11. Clamp; 12. Crossbeam; 13. Pile cap; 14. Adjusting pipe seat; 15. Tubular rubber ring; 16. Reinforcing steel. Implementation

[0058] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] Example 1, such as Figures 1 to 2 As shown, an underwater immersed tube system includes an assembled immersed tube, adjusting pipe seats, a water intake head, a crossbeam 12, a vertical pile, and a splitter. The base of the water intake head is fixed by underwater concrete 10 poured into a steel formwork frame. The crossbeam 12 is set on the vertical pile through a pile cap 13. A pair of adjusting pipe seats 14 are set on the crossbeam 12. The top surface of the adjusting pipe seat 14 is an arc-shaped surface. The immersed tube is placed on the pair of adjusting pipe seats 14. A clamp 11 is fitted on the immersed tube. The two ends of the clamp 11 are connected to the crossbeam 12 to fix the immersed tube. The immersed tubes are connected by splitters. The middle of the splitter arches upward to form a drum-shaped splitter. The splitter is divided into an upper splitter 9 and a lower splitter 8. The upper splitter 9 and the lower splitter 8 are connected by bolts.

[0060] Furthermore, a tubular rubber ring is provided between the half and the submerged tube.

[0061] Furthermore, the tubular rubber ring is fixed with steel bars 16.

[0062] Furthermore, the half is provided with several bolt holes.

[0063] Furthermore, the haf is wrapped with a plastic bag.

[0064] The construction method of the underwater immersed tube system is:

[0065] S1, making a three-dimensional immersed tube simulation model: making a three-dimensional simulation model of the immersed tube according to the same scaling, using the model pipe segment to arrange the lifting point for trial lifting, checking and determining the balanced posture of the immersed tube after lifting, so that the immersed tube is not twisted and displaced after lifting;

[0066] According to the model, the sequence of underwater operations of divers, the operation space, the installation alignment control, the fastening requirements of the fixing parts, the safety protection measures, etc. are explained and briefed;

[0067] S2, excavation of the immersed tube foundation trench: importing the foundation trench plan into the GPS satellite positioning system software of the excavator, excavating soil with the grab bucket excavator, and throwing soil to the designated thalweg area by the open-type barge;

[0068] Excavating according to the safe and stable slope ratio, correcting deviation at any time to avoid over-excavation and under-excavation, and appropriately leaving a margin during the excavation process to meet the space requirements for underwater operations of divers;

[0069] S3, steel pipe pile setting: the GPS of the pile driver first preliminarily positions, then feeds the pile, checks the perpendicularity, simultaneously measures the accurate position by intersection of the total station and the theodolite, sets the steel pipe pile after positioning is completed, and finally controls the elevation of the top of the steel pipe pile by the level;

[0070] S4, installation of the water head: installing the lower half 8 at the end of the connecting pipe on the ground, setting the mark rod on the top of the water head higher than the water surface, adjusting the water head to be flat after lifting, positioning by the GPS, accurately controlling the axis of the mark rod by the total station and the theodolite, checking and verifying by the divers underwater, and the position deviation of the two-way axis is not more than ±50mm;

[0071] S5, installation of the pile cap 13, cross beam 12 and adjusting pipe seat: when the two pile caps 13 supporting the cross beam 12 are installed, the direction of the top connecting steel plate needs to be controlled on a straight line and perpendicular to the axis of the immersed tube; temporarily fixing the left and right adjusting pipe seats on the cross beam 12 before lifting the cross beam 12, and the size between the left and right adjusting pipe seats should be 200mm-300mm larger than the size on the installation drawing;

[0072] When lifting the cross beam 12, the theodolite is set up on the ground to control the position of the axis, and the diver is instructed to move the cross beam 12 underwater, so that the crosshairs of the theodolite and the plumb line of the lifting hook of the cross beam 12 coincide; after the cross beam 12 is in place, the pile cap 13 and the cross beam 12 are connected and fixed by bolts, and the double nuts are tightened;

[0073] S7, installation of the immersed tube, half and clamp 11:

[0074] 1) calibrating the screw hole by trial assembly of the half, installing the fixed pipe type rubber ring, and marking the assembled upper half 9 and lower half 8 clearly with paint;

[0075] 2) When the lower half 8 is connected and fixed to the end of the submerged tube, a water-stopping and leak-proof device should be installed at the bolt hole position;

[0076] 3) The immersed tunnel section is installed using a 500-ton floating crane, which requires three independent hooks;

[0077] 4) Each of the three lifting points on the immersed tube should use a separate hook to facilitate adjustment of the tube's attitude;

[0078] 5) After lifting off the ground, adjust the pipeline axis, height difference, and 3D model posture to maintain consistency;

[0079] 6) The floating crane is self-propelled, with initial GPS positioning;

[0080] 7) Two theodolites are installed on the ground to control the axis at both ends respectively;

[0081] 8) Pull ropes are installed at both ends of the immersed tube to pull and adjust the tube so that it is aligned with the axis direction;

[0082] 9) When the immersed tube sinks 500mm from the design elevation, the diver checks the tube connection and, after confirming that it is correct, places the immersed tube on the crossbeam 12.

[0083] 10) The divers moved the left and right adjustment tube seats one by one until they were completely flush with the tube body and tightened the bolts. After fixing, the lifting steel cable was removed.

[0084] 11) Finally, install the half-clamp 9 and the clamp 11;

[0085] S7. The length and width of the fabric of the molded bag are greater than the size of the half; nylon ropes are threaded through the four sides of the fabric of the molded bag beforehand, and the fabric of the molded bag is guided into the water and hung on both sides of the half by two steel pipes with a diameter of 50mm. After the diver removes the steel pipes underwater and straightens the fabric of the molded bag, all the nylon ropes are fastened.

[0086] S8. When pouring underwater concrete inside the steel formwork frame of the water intake base, the concrete guide pipe should always be inserted into the concrete. The guide pipe should be moved continuously and slowly. The insertion and pouring elevation of the guide pipe should be controlled by the diver.

[0087] After the underwater construction is completed, the water intake head, immersed pipe, and bank slope need to be backfilled and protected. Common protection measures include: laying geotextile soft pads, filling with crushed stone, filling with bagged soil, and filling with boulders.

[0088] The construction principle of the underwater immersed tube system is as follows:

[0089] 1. Use GPS positioning system for initial positioning of the floating crane vessel on the water, and establish a ground measurement and control network for precise control;

[0090] 2. The intersection method using a total station and a theodolite is employed to control the plane deviation of the steel pipe piles;

[0091] 3. Pile marker scale, using a level to read the shore elevation control pipe pile top elevation;

[0092] 4. According to the visual three-dimensional model and simulation model, calculate the pipe processing size, lifting point position and installation sequence;

[0093] 5. Optimize the design to make the assembled fixed parts light in weight, facilitating the diver to operate, move, adjust and install the position;

[0094] 6. The drum-type half makes the pipe connection adjustment more smooth and convenient, and the overall installation quality is controlled;

[0095] 7. Increase the woven bag cloth to wrap the half joint around tightly to prevent leakage;

[0096] 8. Underwater concrete pouring, throwing and filling of gravel and block stones ensure the water intake head and pipe stability against undercurrent scouring.

[0097] Labor organization

[0098] Table 1 Labor organization

[0099] No. Workforce Required number Remarks 1 Management personnel 8 2 Divers 6 3 Steel structure fabrication 25 4 Ship work 15 5 General labor 15 Total 69

[0100] Quality control

[0101] 1. Each sub-item operation error

[0102] 2. Establish a water intake measurement elevation and axis control network, which is used after inspection and acceptance, and the measurement work is assigned to professional personnel;

[0103] 3. After the underwater foundation trench is excavated, three-level inspection and acceptance should be organized to ensure that divers have enough underwater operation space;

[0104] 4. After the pipe and water intake head installation is completed, the axis and elevation error review should be carried out to finally determine the pipe elevation, axis, pipe length and other parameters;

[0105] 5. Steel pipe pile setting and beam installation use two instrument intersection method control, try to reduce the error of each sub-item operation, ensure that the pipe joint error at each half joint is not more than 50mm;

[0106] 6. When steel beams and half are made, they should be numbered in groups and tested on the shore. All connecting bolt holes are checked in advance for completeness and accuracy;

[0107] 7. During the pipe and water intake head lifting operation, a special person is designated to command, and the shore instrument control is combined with the diver's underwater inspection to complete the work together.

[0108] Benefit analysis

[0109] 1. Cost (take the sentence container power plant as an example)

[0110] After adopting separate construction, labor is saved (170 workdays * 220 yuan / workday = 37400 yuan), 25t crane use shifts are saved (21 shifts * 2600 yuan / shift = 54600 yuan), 500-ton ship use shifts are saved (7 shifts * 40000 yuan / shift = 280000 yuan), production site is saved (1500m2*180 yuan / m2=270000 yuan), steel structure production platform is saved (14t*8000 yuan / t=112000 yuan), and the total cost saving is 754000 yuan.

[0111] 2. Shorten construction period

[0112] Adjusting pipe seat and sinking pipe are separately produced, saving 9 days of construction period, and installation saves 14 days of construction period, and the total construction period is shortened by 23 days.

[0113] 3. Save circulating pump house operation and maintenance cost

[0114] On the basis of pipe type rubber ring sealing between sinking pipe and half, bag wrapping is added to prevent the common problem of large amount of sediment deposition in circulating pump house in the future. Usually, circulating pump house needs to be dredged once every one to two years during the operation stage, and the cost of each dredging is about 200,000 yuan.

[0115] Application example

[0116] 1. Huaneng Nanjing Jinling gas turbine power plant 3*350MW

[0117] Circulating water intake head 1 (including 9 underwater steel pipe piles Φ600x12 pile foundation); Φ4.0m water intake pipe 1 (including 12 underwater steel pipe piles Φ600x12 pile foundation), of which the total length of the pipe jacking is 90m (slope 7%), and the underwater sinking pipe is 60m. Our company prepared the "Three-dimensional sinking pipe underwater installation construction method", which optimizes the structure details on the basis of the original construction drawing. The underwater operation of the diver is fast and convenient, and the underwater installation quality is improved.

[0118] 2. Huanrui Nanjing power plant 2*600MW

[0119] Steel water intake head 2 (including 18 underwater steel pipe piles Φ609x14 pile foundation), total length of water intake pipe is 596.17 meters, specification is Φ3240*36mm steel pipe, two underwater sinking pipes (including 8 underwater steel pipe piles Φ609x14 pile foundation), single length is 40 meters. The underwater sinking pipe is constructed according to the "Three-dimensional sinking pipe underwater installation construction method". This construction method has been applied in the water intake construction of Huaneng Nanjing Jinling gas turbine power plant, and after further improvement and perfection, the process is more mature and reliable, the labor efficiency is improved, the construction cost is saved, and the underwater engineering construction quality is improved.

[0120] 3. Huadian Jucong Power Plant Phase 1 Project 2*1000MW

[0121] Three water intake heads (including 27 underwater steel pipe piles Φ914x14 pile foundations); three water intake steel pipes, outer diameter 3440mm, wall thickness 36mm, single length 250 meters; underwater steel pipe connection between water intake head and pipe, total length 188 meters (including 68 underwater steel pipe piles Φ609x14 pile foundations), divided into seven sections for production and installation; pipe diameter 3440mm, pipe length 55.74m (divided into two sections for sinking), 61.13m (divided into two sections for sinking), 70.24m (divided into three sections for sinking). The underwater pipe is constructed according to the "Three-dimensional pipe sinking underwater installation construction method", which has been continuously applied and improved in the water intake construction of Huaneng Nanjing Jinling Gas Turbine Power Plant and Huarun Nanjing Thermal Power Plant. The process flow is reasonable, the installation speed is fast and the precision is high. In the process of water intake pipe sinking construction of Huadian Jucong Power Plant, the construction quality of underwater pipe sinking can be fully improved, and the requirements of power plant trial operation debugging are guaranteed. The method has been mature.

[0122] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application also intends to include these modifications and variations.

Claims

1. A construction method of an underwater immersed tube system, the underwater immersed tube system comprising an assembled immersed tube, an adjusting pipe base, a water intake head, a crossbeam, a standing pile, a half, a base of the water intake head is fixed by pouring underwater concrete with a steel mold frame, the crossbeam is arranged on the standing pile through a pile cap, a pair of adjusting pipe bases are arranged on the crossbeam, a top surface of the adjusting pipe base is an arc surface, the immersed tube is placed on the pair of adjusting pipe bases, a clamp is sleeved on the immersed tube, two ends of the clamp are connected to the crossbeam to fix the immersed tube, the immersed tubes are connected through the half, a middle part of the half is arched upward to form a drum half, the half is divided into an upper half and a lower half, the upper half and the lower half are connected through bolts; characterized in that The method comprises the following specific steps: S1, a three-dimensional immersed tube simulation model is made according to the same scaling, the model pipe section is used to arrange a lifting point to perform a trial lifting, and the balance posture of the immersed tube after being lifted is checked and determined, so that the immersed tube is not twisted and displaced after being lifted; the underwater operation sequence of a diver, an operation space, installation alignment control, installation and fastening requirements of a fixing part, and safety protection measures are explained and briefed according to the model; S2, immersed tube foundation trench excavation: a foundation trench excavation plan is introduced into a GPS satellite positioning system software of a grab bucket dredger, the grab bucket dredger excavates soil, and an open type barge throws soil to a specified thalweg region of a maritime department; the excavation is performed according to a designed safe and stable slope ratio, deviation is corrected in time to avoid overexcavation and underexcavation, and a rich degree is appropriately left during the excavation process to meet the space requirements of the underwater operation of the diver; S3, steel pipe pile setting: A GPS of a pile driver is preliminarily positioned, then a pile is fed, perpendicularity inspection is performed, a total station instrument and a theodolite are intersected to measure and accurately position, the steel pipe pile is set after positioning is completed, and finally, the elevation of the top of the steel pipe pile is controlled by a level instrument; S4, water intake head installation: a lower half of a connecting pipe end is installed on the ground, a marker rod is arranged on the top of the water intake head and is higher than the water surface; the water intake head is adjusted to be flat after being lifted; the floating crane is self-propelled, the GPS is preliminarily positioned, the marker rod axis is accurately controlled by the total station instrument and the theodolite; the underwater inspection and checking of the diver are performed, and the position deviation of the bidirectional axis is not greater than ±50 mm; S5, pile cap, crossbeam and adjusting pipe base installation: when the two pile caps of the crossbeam are placed, the direction of the top connecting steel plate needs to be controlled on a straight line and perpendicular to the axis of the immersed tube; the left and right adjusting pipe bases are temporarily fixed on the crossbeam before the crossbeam is lifted, the size between the left and right adjusting pipe bases is 200 mm to 300 mm larger than the size on the installation drawing; the theodolite is arranged on the ground to control the position of the axis during the lifting of the crossbeam, and the diver is instructed to move the crossbeam underwater to make the cross of the theodolite and the lifting hook plumb line of the crossbeam coincide; after the crossbeam is positioned, the pile cap and the crossbeam are fixed and connected through bolts, and the double nuts are tightened; S6, immersed tube, half and clamp installation: 1) the half is tried to assemble and calibrated, a pipe type rubber ring is installed, and the upper half and the lower half are clearly marked with paint after being assembled; 2) when the lower half is connected and fixed with the end of the immersed tube, the bolt hole position should be set to prevent water seepage; 3) the immersed tube is lifted by a 500-ton floating crane, and three independent lifting hooks are needed; 4) three lifting points of the immersed tube should use separate lifting hooks to facilitate adjustment of the posture of the immersed tube; 5) Adjust the pipeline axis, height difference and three-dimensional model posture after lifting off the ground to keep consistent; 6) Float the crane, and preliminarily position by GPS; 7) Set up two theodolites on the ground to control the two ends of the axis; 8) Set up a pull rope at the two ends of the immersed tube to pull and adjust the pipeline to make it consistent with the axis direction; 9) When the immersed tube is sunk to 500mm from the design elevation, the diver checks the pipe joint and confirms the correctness, and then places the immersed tube on the cross beam; 10) The diver moves left and right to adjust the pipe seat one by one, so that it is completely attached to the pipe body and the bolts are tightened, and then the lifting steel cable is removed; 11) Install the upper half and the clamp; S7, the processing length and width of the mold bag cloth is greater than the size of the half; the four edges of the mold bag cloth are provided with nylon ropes in advance, two steel pipes with a diameter of 50mm are used to guide the mold bag cloth to sink into the water and hang on the two sides of the half, the diver removes the steel pipes along the mold bag cloth under water, and then all the nylon ropes are buckled; S8, when pouring the underwater concrete in the steel mold frame of the water intake base, the concrete guide pipe should be always inserted into the concrete, the guide pipe should be continuously and slowly moved, and the insertion and pouring elevation of the guide pipe is controlled by the diver; After the underwater construction work is completed, the water intake head, the immersed tube and the bank slope are backfilled and protected; In S8, the protective measures include laying a soft soil cloth, throwing and filling gravel, throwing and filling bagged soil, and throwing and filling block stones.

2. A method of construction of an underwater immersed tube system according to claim 1, characterised in that, A pipe-shaped rubber ring is arranged between the half and the immersed tube.

3. A method of construction of an undersea immersed tube system as claimed in claim 1, wherein, The pipe-shaped rubber ring is fixed by steel bars.

4. A method of construction of an underwater immersed tube system according to claim 1, wherein, A plurality of bolt holes are formed in the half.

5. A method of construction of an underwater immersed tube system according to claim 1, wherein, The half is wrapped with a mold bag cloth.

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