Offshore water intake head foundation

Abstract

The utility model discloses an offshore water taking head foundation which is composed of a group pile foundation and a steel mould assembly arranged from bottom to top. The group pile foundation comprises N steel pipe piles, N pile caps and a water taking device fixing frame. The N pile caps are respectively sleeved and fixed on the top sides of the N steel pipe piles, and the top sides of the pile caps are provided with lower connecting flanges. The water taking device fixing frame comprises an annular body, and N upper connecting flanges are fixed on the bottom surface of the annular body in a circumferential direction. The steel mould assembly comprises a steel mould frame, a plurality of limiting frames are arranged side by side and spaced apart, and are fixed on the inner wall of the steel mould frame. The limiting frames are provided with pile foundation limiting holes, and the number and positions of the pile foundation limiting holes on the plurality of limiting frames correspond to the underwater setting positions of the N steel pipe piles one by one. The water taking head installation construction method implemented by using the foundation can greatly reduce the earthwork amount of the open caisson sinking process, improve the pile foundation plane positioning accuracy, and shorten the time of each construction procedure by 2-3 times compared with the traditional process operation, so that the construction efficiency is high and the cost is low.

Description

Technical Field

[0001] This utility model relates to the field of underwater structure construction technology in marine engineering, and in particular to a marine water intake head foundation. Background Technology

[0002] Offshore intake head construction is a crucial step in marine engineering, primarily used in seawater desalination, power plant cooling water systems, and oil platform water supply. Currently, offshore intake head construction faces three major technical bottlenecks: 1) Traditional excavation methods are prone to slope collapse in deep-water, soft soil areas, resulting in large excavation volumes and backfilling amounts reaching 150%–200% of the design volume; 2) In pile foundation construction, the underwater planar positioning deviation of multiple steel pipe piles generally exceeds 50mm, making it impossible to assemble the superstructure; 3) Bolt holes on the prefabricated pile foundations and intake head flanges are difficult to align during underwater construction, consuming significant time and posing high risks to underwater operations. Therefore, it is necessary to further improve existing intake head installation methods to solve the technical challenges encountered in the current construction process. Utility Model Content

[0003] The purpose of this invention is to provide a marine water intake foundation that solves the problems of low construction efficiency and poor accuracy in existing marine water intake structures, especially for the precise positioning and efficient installation of water intake structures for large-scale projects such as LNG receiving terminals and nuclear power plants.

[0004] Therefore, the technical solution of this utility model is as follows:

[0005] A type of offshore water intake foundation consists of a pile group foundation and steel formwork components installed from bottom to top; wherein...

[0006] The pile foundation consists of N steel pipe piles, N pile caps, and a water intake device fixing frame. The N steel pipe piles are evenly distributed and supported at the bottom of the water intake device. The N pile caps are respectively fitted and fixed on the top side of the N steel pipe piles, and the top side of the pile caps is provided with an unperforated lower connecting flange. The water intake device fixing frame includes an annular body that conforms to the shape of the bottom surface of the water intake device. N upper connecting flanges are evenly distributed and fixed on the bottom surface of the annular body along the circumferential direction.

[0007] The steel formwork assembly includes a steel formwork frame, which is a frame that runs vertically through the body. Multiple limiting frames are arranged side by side at intervals and fixed to the inner wall of the steel formwork frame. Each limiting frame is provided with a pile foundation limiting hole that is adapted to the outer diameter of the steel pipe pile. The number and position of the pile foundation limiting holes on the multiple limiting frames correspond one-to-one with the underwater driving positions of N steel pipe piles.

[0008] Furthermore, the pile cap includes a cylindrical sleeve with a lower connecting flange horizontally fixed on the top side of the sleeve; two bolt holes are symmetrically opened on the side wall of the sleeve, and a locking bolt that can pass through the two bolt holes and a locking nut for threaded connection and fixing to both ends of the locking bolt are provided.

[0009] Furthermore, multiple reinforcing ribs are evenly distributed along the circumferential direction on the top side of the sleeve, and each reinforcing rib is connected and fixed to the bottom surface of the lower connecting flange and the outer wall of the sleeve.

[0010] Furthermore, the steel mold frame is split into a left U-shaped frame and a right U-shaped frame, and on the outer wall edges of the two U-shaped frames at the joint end, a strip connecting frame is fixed along the extension direction of the edge, so that the two U-shaped frames are connected and fixed by multiple bolts that are spaced through the two strip connecting frames on the same side.

[0011] Furthermore, at least one reinforcing brace is diagonally provided between adjacent inner walls at each corner of the steel formwork frame, and two reinforcing ribs are also provided at intervals on the circumferential outer walls of the two U-shaped frames.

[0012] Furthermore, multiple tilt sensors are evenly distributed along the circumference on the inner wall of the steel mold frame.

[0013] Furthermore, multiple lifting lugs are evenly distributed along the circumference on the inner wall of the steel mold frame, and each lifting lug group includes at least two lifting lugs.

[0014] Furthermore, the limiting frame includes two parallel support rods, the ends of which are fixed to the inner wall of the steel formwork frame; multiple limiting rod groups are arranged between the two support rods, each group consisting of two limiting rods vertically fixed between the two support rods, so that the two limiting rods and the two support rods together form a pile foundation limiting hole.

[0015] Compared with existing technologies, the use of this offshore intake head foundation for intake head construction reduces the earthwork volume in the caisson sinking process by 65% ​​or more, and the pile foundation plane positioning accuracy reaches ±35mm, far less than the national standard allowable construction mark of ±50mm. Furthermore, in the entire construction process, the sequential process of formwork sinking and pipe pile driving, the underwater connection and assembly process of pile caps and pile foundations, and the installation and fixing process of water intake device and pile group foundation all significantly shorten the operation time by 2-3 times compared with traditional construction methods, effectively improving construction efficiency and reducing construction costs. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the water intake head installation construction method using an offshore water intake head foundation according to this utility model.

[0017] Figure 2 This is a schematic diagram of the structure of the present invention for completing the construction of the water intake head using an offshore water intake head foundation;

[0018] Figure 3 This is a schematic diagram of the structure of a water-taking device with a water-taking device fixing frame installed at the bottom in an embodiment of this utility model;

[0019] Figure 4 Schematic three-dimensional structure diagram of the steel mold assembly of the offshore water intake head foundation in the embodiment of the present utility model;

[0020] Figure 5 Top view of the steel mold assembly of the offshore water intake head foundation in the embodiment of the present utility model;

[0021] Figure 6 Schematic top-side structure diagram of the group pile foundation of the offshore water intake head foundation in the embodiment of the present utility model

[0022] Figure 7 Schematic structure diagram of the docking state between the group pile foundation of the offshore water intake head foundation and the water intake device in the embodiment of the present utility model;

[0023] Figure 8 Cross-sectional view of the connection state between the steel pipe pile and the pile cap in the group pile foundation of the offshore water intake head foundation in the embodiment of the present utility model;

[0024] Figure 9 Cross-sectional view of excavating the original mud surface by using the offshore water intake head foundation to form a mud groove with an internal steel mold frame in the embodiment of the present utility model;

[0025] Figure 10 Cross-sectional view of the offshore water intake head foundation and the water intake device after completing the construction of the water intake head by using the offshore water intake head foundation in the embodiment of the present utility model. Specific embodiments

[0026] The following further describes the present utility model in conjunction with the accompanying drawings and specific embodiments, but the following embodiments are by no means any limitation to the present utility model.

[0027] See Figures 1-10 , taking the water intake head construction of a certain LNG project in Tangshan as an example, the offshore water intake head foundation of the present utility model and its construction method are described in detail as follows.

[0028] As Figure 2 shown, the offshore water intake head foundation is composed of a group pile foundation and a steel mold assembly arranged from bottom to top. Among them, the group pile foundation is used as an underwater foundation structure to support and fix the water intake device 100; the steel mold assembly is an auxiliary operation structure that combines the functions of caisson sinking excavation, pile foundation limit, and caisson template, and is used to assist the entire water intake head construction process and finally form a concrete caisson 240.

[0029] Based on the water intake head construction requirements of this embodiment, the group pile foundation includes seven steel pipe piles 220, seven pile caps 230, and a water intake device fixing frame.

[0030] Refer Figure 6 and Figure 7Seven steel pipe piles 220 are used to support the bottom center of the water intake device 100 and to support the circumferential edges of the bottom of the water intake device 100, respectively, so as to provide stable support for the water intake device 100.

[0031] See Figure 6 and Figure 8 Seven pile caps 230 are respectively installed on the top side of seven steel pipe piles 220 to form a connection at the pile top; specifically, the pile cap 230 includes a cylindrical sleeve, and a lower connecting flange without holes is horizontally fixed on the top side of the sleeve; wherein, the inner diameter of the sleeve is larger than the outer diameter of the pile top of the steel pipe pile 220, so that the pile cap 230 can be fitted on the top side of the steel pipe pile 220; two bolt holes 231 are symmetrically opened on the side wall of the sleeve, and locking bolts 232 that can pass through the two bolt holes 231 are provided, and locking nuts 233 for threaded connection and fixation at both ends of the locking bolts 232 are provided; preferably, multiple reinforcing ribs are evenly distributed along the circumferential direction on the top side of the sleeve, and each reinforcing rib is connected and fixed to the bottom surface of the lower connecting flange and the outer wall of the sleeve.

[0032] Initially, no holes are pre-drilled on the top side of the steel pipe pile 220. Then, during the water intake construction, through holes are drilled underwater in the radial direction. Specifically, when the pile cap 230 is fitted onto the top of the steel pipe pile 220, underwater workers drill holes in the top of the steel pipe pile 220 based on the two bolt holes 231 on the pile cap 230, so that the hole in the pile top is directly connected to the two bolt holes 231. Then, the pile cap 230 can be fastened to the top side of the steel pipe pile 220 by the locking bolts 232 that are sequentially inserted on the pile cap 230 and the steel pipe pile 220, and the locking nuts 233 that are threaded to both ends of the locking bolts 232.

[0033] See Figure 7 The water intake device mounting bracket is pre-welded and fixed to the bottom surface of the water intake device 100, and specifically includes a connecting bracket and seven upper connecting flanges 110; wherein,

[0034] The connecting frame includes an annular body that conforms to the shape of the bottom surface of the water intake device 100, with its top surface welded and fixed to the bottom surface of the water intake device 100. Seven upper connecting flanges 110 are evenly distributed and fixed to the bottom surface of the annular body along the circumferential direction. Each upper connecting flange 110 is a circular disc without flange bolt holes 111, which can be opened underwater during subsequent construction according to the position of the flange holes on the lower flange of each pile cap 230, so as to achieve rapid fixed connection between the water intake device 100 and the pile foundation. Preferably, in order to improve the structural strength of the connecting frame, multiple steel plates are welded and fixed on the annular body in an intersecting manner.

[0035] See Figure 4 and Figure 5The steel formwork assembly includes a steel formwork frame 210 and a limiting frame 213. The steel formwork frame 210 is a cubic steel frame with openings at the top and bottom, and its inner diameter is larger than the outer diameter of the pile foundation. Multiple limiting frames 213 are provided at intervals and side by side inside the steel formwork frame 210, which are adapted to the design number and design position of the piles 200 constituting the pile foundation.

[0036] The steel mold frame 210 is split into a left U-shaped frame 211 and a right U-shaped frame 212 to facilitate manufacturing, transportation, and hoisting. On the outer wall edges of the two U-shaped frames at their joint ends, a strip-shaped connecting frame 216 is vertically arranged along the extension direction of each edge, allowing the two U-shaped frames to be detachably connected and fixed as one unit by multiple bolts 218 that are spaced apart and pass through the two strip-shaped connecting frames 216 on the same side. In this embodiment, the two strip-shaped connecting frames 216 can specifically be C-shaped steel. The two C-shaped steels on the same side are welded and fixed to the side wall edges of the left U-shaped frame 211 and the right U-shaped frame 212 with opposite openings. When the left U-shaped frame 211 and the right U-shaped frame 212 are joined together to form a steel mold frame 210, the two C-shaped steels on the same side are also in contact with each other. Then, the connection can be achieved by opening bolt holes 217 at equal intervals on the bottom surface of the two C-shaped steels, inserting bolts 218, and setting fastening nuts.

[0037] Preferably, two reinforcing braces 219 are diagonally provided at each of the four corners on the top side of the steel mold frame 210. Specifically, the two reinforcing braces 219 at each corner are horizontally spaced apart, and the two ends of each reinforcing brace 219 are fixed to the inner walls of the frame on both sides forming the corner. At the same time, two reinforcing ribs are fixed circumferentially on the outer walls of the left U-shaped frame 211 and the right U-shaped frame 212, respectively. The two reinforcing ribs are parallel and centered on the outer wall of each U-shaped frame to increase the structural strength of the steel mold frame 210 and prevent the steel mold frame 210 from deforming during operation.

[0038] According to the actual construction design of this embodiment, a total of seven steel pipe piles 220 need to be lowered during the construction process. The design positions of the seven steel pipe piles 220 can be divided into three columns, with the number of steel pipe piles in each column being 2, 3 and 2 respectively. Based on this, three limiting frames 213 are set up, which are arranged in parallel with equal intervals on the bottom surface of the steel formwork frame 210, and the interval distance is consistent with the column width as described above.

[0039] In this embodiment, each limiting frame 213 includes two parallel support rods, the ends of which are welded and fixed to the inner wall of the steel formwork frame 210; multiple limiting rod groups are arranged between the two support rods, each limiting rod group consisting of two limiting rods vertically fixed between the two support rods, so that each limiting rod group and the two support rods together form a pile foundation limiting hole, and the diameter of each pile foundation limiting hole is adapted to the outer diameter of the corresponding pile foundation 220.

[0040] As a preferred technical solution of this embodiment, in order to ensure the horizontal installation of the steel formwork frame 210, an inclination sensor 214 is provided on each of its four side walls; the four inclination sensors 214 are used to monitor the inclination of the steel formwork frame 210 during the sinking process; specifically, when the inclination deviation of the steel formwork frame 210 exceeds 0.5% during the sinking process, dredging and correction are initiated.

[0041] As another preferred technical solution of this embodiment, two lifting lugs 215 are provided at intervals on each of the four side walls of the steel mold frame 210, which are evenly distributed on the left U-shaped frame 211 and the right U-shaped frame 212 to facilitate hoisting and assembly.

[0042] See Figure 1 , Figure 2 , Figure 7 , Figure 9 and Figure 10 The specific implementation steps of the intake head installation construction method using the above-mentioned offshore intake head foundation are as follows:

[0043] Step 1: Determine the number and specifications of steel pipe piles constituting the pile group foundation based on the size and specifications of the water intake device 100 and the geological characteristics of the construction location. Based on this, prefabricate the pile group foundation and steel formwork components, and pre-fix the water intake device fixing frame of the pile group foundation to the bottom surface of the water intake device 100. The prefabricated steel formwork frame has dimensions of 12m×8m×6m, Q355 steel plate thickness of 20mm, and H200 channel steel for the limiting frame. The center distance tolerance of the 7 pile foundation limiting holes is ±1.5mm.

[0044] Step 2: Drive auxiliary positioning piles to determine the planar setting position of the steel formwork frame 210; assemble the steel formwork frame 210 and hoist it to the designated position on the original mud surface; in this embodiment, the original mud surface is at -9m, and the design bottom elevation of the concrete foundation formed by the steel formwork frame 210 is set to -15.66m.

[0045] Step 3: Soil is removed from inside the steel formwork frame 210 using a high-pressure water gun and hydraulic dredging. Simultaneously, four tilt sensors 214 on the steel formwork frame 210 are used to monitor its verticality in real time, allowing for adjustments to the positions of the high-pressure water gun and dredging equipment as needed, until the steel formwork frame 210 is lowered to the design elevation using a caisson process. For example, if the northeast corner showed a slower sinking rate during construction, a directional high-pressure water gun (3MPa pressure) was used to flush the soil in that area. After the above correction operation, the tilt of the steel formwork frame 210 decreased from 0.8% to 0.4%. After the steel formwork frame 210 is lowered to the design position, the tilt sensors 214 are removed for reuse.

[0046] Step 4: The steel pipe piles 220 are hoisted into the steel formwork frame 210 in sequence and sent into the pile foundation limiting holes set on each limiting frame 213, thereby guiding the vibratory hammer to drive the steel pipe piles 220; the top elevation of the driven piles is not less than 1.5m above the water surface;

[0047] Step 5: Cut the steel pipe pile 220mm underwater to the design elevation;

[0048] Step 6: Install a pile cap 230 on the top side of the steel pipe pile, and according to the opening position of the bolt hole 231 on the pile cap 230, open a through bolt hole on the top of the steel pipe pile 220. Then, insert fastening bolts 232 on the pile cap 230 and the top of the steel pipe pile 220 and install fastening nuts 233 to fix the pile cap 230 on the top side of the steel pipe pile 220.

[0049] Step 7: The crane vessel lifts the water intake device 100 above the pile foundation and aligns the seven upper flanges on the water intake device mounting frame with the lower flanges on the seven pile caps 230; the underwater diver uses the flange bolt holes on each lower connecting flange to drill bolt holes 111 on the corresponding upper connecting flange, and inserts bolts 112 and tightens nuts 113, thereby completing the connection between the water intake device 100 and the pile foundation;

[0050] Step 8: Inject underwater concrete into the cavity inside the steel formwork frame 210 through the grouting pipe 120, and observe underwater until the concrete completely fills the steel formwork frame 210, so as to form a concrete foundation 240 integrally formed by the steel formwork frame 210 and the cured concrete, ensuring the stable setting of the water intake device 100 on the water.

[0051] In the specific implementation steps of this embodiment, a grouting pipe 120 is pre-set along the axial direction at the center of the water intake device 100, and the inner cavity of the pipe is not connected to the inner cavity of the water intake device 100; the concrete mixing boat of the water intake device is close to the water intake head area, and the grouting pipe 120 on the water intake head is connected to the pump pipe to inject concrete underwater. When underwater observation shows that the concrete has completely filled the steel mold frame and some has overflowed, the injection is stopped.

[0052] In the actual construction of this embodiment, the steel formwork frame sinking method of this utility model was used to achieve excavation to -15.66m without slope, which reduced the amount of excavation by approximately 7800m³ compared to traditional construction methods. 3The reduction rate was approximately 75.4%. Due to the use of a steel formwork frame 210 with an internal limiting frame 213 for driving the steel pipe piles, the maximum planar deviation of the steel pipe piles was only 3.3 cm. The method of underwater cutting of the pile head and using pile caps to drill holes in the pile top for bolt connection and fixation achieved a 100% bolt penetration success rate, with the installation time for the seven pile caps 230 being only 180 minutes. Furthermore, the use of flange connections between the water intake device 100 and each steel pipe pile, along with the construction strategy of drilling holes after connecting the upper flange, achieved a 100% bolt penetration success rate, with the entire positioning and installation construction time for the water intake device 100 being only 110 minutes.

Claims

1. A marine water intake foundation, characterized in that, It consists of a pile foundation arranged from bottom to top and steel formwork components; among which... The pile foundation includes N steel pipe piles (220), N pile caps (230), and a water intake device fixing frame; the N steel pipe piles (220) are evenly distributed and supported at the bottom of the water intake device (100), and the N pile caps (230) are respectively fitted and fixed on the top side of the N steel pipe piles (220), and the top side of the pile caps (230) is provided with an unperforated lower connecting flange; the water intake device fixing frame includes an annular body that conforms to the shape of the bottom surface of the water intake device (100), and N upper connecting flanges (110) are evenly distributed and fixed on the bottom surface of the annular body along the circumferential direction; The steel formwork assembly includes a steel formwork frame (210), which is a frame that runs vertically through the body. Multiple limiting frames (213) are arranged side by side at intervals and fixed on the inner wall of the steel formwork frame (210). Each limiting frame (213) is provided with a pile foundation limiting hole that is adapted to the outer diameter of the steel pipe pile. The number and position of the pile foundation limiting holes on the multiple limiting frames (213) correspond one-to-one with the underwater driving positions of the N steel pipe piles (220).

2. The offshore water intake foundation according to claim 1, characterized in that, The pile cap (230) includes a cylindrical sleeve with a lower connecting flange fixed horizontally on the top side of the sleeve; two bolt holes (231) are symmetrically opened on the side wall of the sleeve, and a locking bolt (232) that can pass through the two bolt holes (231) is provided, as well as a locking nut (233) for threaded connection and fixed at both ends of the locking bolt (232).

3. The offshore water intake foundation according to claim 2, characterized in that, Multiple reinforcing ribs are evenly distributed along the circumference on the top side of the sleeve, and each reinforcing rib is connected and fixed to the bottom surface of the lower connecting flange and the outer wall of the sleeve.

4. The offshore water intake foundation according to claim 1, characterized in that, The steel formwork frame (210) is split into a left U-shaped frame and a right U-shaped frame. On the outer wall edges of the two U-shaped frames at the joint end, a strip connecting frame (216) is fixed along the extension direction of the edge, so that the two U-shaped frames are connected and fixed by multiple bolts (218) that are spaced through the two strip connecting frames (216) on the same side.

5. The offshore water intake foundation according to claim 2, characterized in that, At least one reinforcing brace (219) is provided diagonally between adjacent inner walls at each apex of the steel formwork frame (210), and two reinforcing ribs are also provided at intervals on the circumferential outer walls of the two U-shaped frames.

6. The offshore water intake foundation according to claim 1, characterized in that, Multiple tilt sensors (214) are evenly distributed along the circumference on the inner wall of the steel mold frame (210).

7. The offshore water intake foundation according to claim 1, characterized in that, Multiple lifting lugs are evenly distributed along the circumference on the inner wall of the steel formwork frame (210), and each lifting lug group includes at least two lifting lugs (215).

8. The offshore water intake foundation according to claim 1, characterized in that, The limiting frame (213) includes two parallel support rods, the ends of which are fixed to the inner wall of the steel formwork frame (210); multiple limiting rod groups are provided between the two support rods, each group consisting of two limiting rods vertically fixed between the two support rods, so that the two limiting rods and the two support rods together form a pile foundation limiting hole.

Images