Fabricated steel platform under deepwater bare rock condition and construction method thereof

Abstract

The invention discloses a fabricated steel platform under a deepwater bare rock condition and a construction method of the fabricated steel platform. The fabricated steel platform comprises a gravel throwing and filling layer, counterweight concrete, a jacket, a top support and a steel truss. According to the platform, the weight of the jacket is increased by arranging the counterweight concrete, the stability problem of the platform in the marine environment is solved, the working procedure of constructing concrete anchor piles through a traditional jacket is avoided, meanwhile, the whole platform adopts the factory prefabrication concept, the lower structure and the upper structure are both machined and manufactured in a factory, and cost is reduced. The steel platform is transported to a construction site and assembled construction is adopted to form a formal steel platform, the offshore operation time is shortened, and the safety risk is reduced; the platform is high in construction efficiency, short in construction period and high in adaptability in deepwater sea areas with complex environments; the platform can be repeatedly used, can be used as various underwater foundation construction platforms after being simply modified, and is high in economical efficiency, wide in applicability and reliable in safety.

Description

Technical Field

[0001] This invention relates to the field of offshore construction technology, and in particular to a prefabricated steel platform and its construction method under deep-water bare rock conditions. Background Technology

[0002] As bridges develop towards longer spans, lighter weight, higher strength, and more integrated designs, the forms of bridge foundation structures are undergoing rapid changes. Bridge construction is also expanding from major rivers to sea-crossing bridges. The construction of sea-crossing bridges can not only significantly promote the development of the coastal economy but also meet the needs of national maritime strategic security. With the explosive growth of sea-crossing bridge construction, bridge sites are gradually shifting from nearshore to deep-sea areas.

[0003] Currently, offshore construction in China mainly uses steel trestle bridges as construction platforms and passageways. In nearshore areas with thick overburden, steel pipe pile driving is relatively easy, and the side friction resistance of steel pipe piles is relatively large, so the support capacity meets the requirements. However, in deep water and bare rock areas without overburden, steel pipe pile driving is extremely difficult, and is greatly affected by factors such as water depth, wind, waves, currents and tides, resulting in short effective working time and high safety risks. Summary of the Invention

[0004] The first objective of this invention is to provide a prefabricated steel platform that is low in cost, highly efficient in construction, has good stress distribution, and is suitable for deep-water bare rock conditions, which can solve the problem of rapid construction in complex deep-water bare rock conditions.

[0005] The second objective of this invention is to provide a construction method for prefabricated steel platforms under deep-water bare rock conditions.

[0006] The object of the present invention is achieved like this: A prefabricated steel platform for deep-water bare rock conditions is characterized by comprising a gravel fill layer, counterweight concrete, a jacket, a top support, and a steel truss. The jacket includes steel pipe piles, a connecting system, and a delivery pipe. The bottom of the steel pipe piles is vertically fixed in the rock layer below the seabed. A gravel fill layer for leveling the seabed surface of the jacket is provided at the bottom of the steel pipe piles. Counterweight concrete is provided at the bottom of the steel pipe piles and in the gravel fill layer to increase the weight of the jacket and thus its stability. The delivery pipe is installed inside the steel pipe piles for pumping concrete and pouring the counterweight concrete at the bottom of the jacket. The steel truss is the superstructure, and a top support is provided between the top of the jacket and the bottom of the steel truss as a force transmission structure. A single jacket consists of three steel pipe piles connected by a connecting system to form a triangular frame structure.

[0007] Furthermore, the counterweight concrete at the bottom of the jacket is graded C30 and is a cuboid structure with dimensions of 9000*3000*9000mm.

[0008] Furthermore, the steel truss is welded from HN900*300 and HM588*300 steel sections.

[0009] Furthermore, the steel pipe pile has a diameter of 2400mm and a wall thickness of 28mm, while the connecting system has a diameter of 800mm and a wall thickness of 12mm.

[0010] Furthermore, the top support is made of spliced ​​steel plates of material Q235B.

[0011] The second objective of this invention is achieved as follows: A construction method for prefabricated steel platforms in deep-water bare rock conditions, characterized by the following specific steps: Step 1: Fill the seabed with gravel to level the surface and obtain a gravel fill layer: A. Use GPS positioning to determine the leveling range of the guide frame; B. Within the leveling area, crushed stones are dumped to treat the uneven original seabed surface so that the leveled seabed surface reaches the design elevation. Step 2: Fabrication and transportation of the jacket structure to the pier location for placement. A. Assemble and process three steel pipe piles and multiple sets of connecting ropes into a complete guide frame in the factory; B. The top support of the guide frame is processed and installed in the factory, and the top support together with the guide frame is hoisted and lowered as a whole; C. After passing the inspection, the processed jacket structure will be stored as a whole on a transport ship using a large floating crane and transported to the construction area. Step 3: Precise positioning and lowering of the catheter stent A. Use a large floating crane to lift a single set of jackets from the transport ship and lower them to the pier location. Use GPS for precise positioning to assist in lowering the jackets to the designed position on the seabed. Step 4: Pouring counterweight concrete A. Install the formwork at the bottom of the guide frame in advance, and pump concrete into the formwork through the delivery pipe inside the steel pipe pile to complete the pouring of the counterweight concrete at the bottom of the guide frame. Step 5: Installation of remaining guide frames and pouring of counterweight concrete. A. Repeat steps two and three to complete the installation of the remaining duct supports; B. Repeat step four to complete the pouring of the remaining counterweight concrete; Step Six: Installation and Lowering of the Truss Platform A. The steel truss is processed in the processing plant, and after processing, it is transported to the construction area by a large transport ship and anchored for positioning. B. Use a large floating crane to lift and install the steel truss onto the top support of the jacket frame, and adjust the elevation; C. Connect the steel truss with the top support to form an integrated platform, and then proceed with the main construction.

[0012] Advantages of the present invention: 1. By setting counterweight concrete at the bottom of the jacket, the stability problem of the jacket in deep-sea marine environment can be solved, avoiding the concrete anchor pile process of traditional jacket construction, reducing offshore operation time and lowering safety risks. 2. The steel platform adopts a prefabrication concept, with a jacket structure for the substructure and a steel truss structure for the superstructure. Both the substructure and superstructure are manufactured in the factory, and can be fabricated as a whole or in sections depending on the lifting and processing capabilities. The substructure and superstructure are transported to the construction site by ship for overall installation. The superstructure is also fabricated as a whole or in sections according to the lifting and processing capabilities, and then transported to the site for installation. The assembly-based construction of the substructure and superstructure forms the final steel platform, thereby reducing offshore operation time and lowering safety risks. 3. The steel platform has high construction efficiency and short construction period, and is highly adaptable to complex deep-sea environments. 4. This steel platform is reusable, economical, widely applicable, and safe.

[0013] This invention can be easily modified to be applied to the construction of various underwater foundations. Attached Figure Description

[0014] Figure 1 This is a plan view of the present invention; Figure 2 This is an elevation layout diagram of the present invention; Figure 3 This is a side view of the present invention; Figure 4 This is an elevation view of the catheter holder of the present invention. Detailed Implementation

[0015] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0016] A prefabricated steel platform for deep-water bare rock conditions includes a gravel fill layer 1, counterweight concrete 2, a jacket 3, a top support 4, and a steel truss 5. The jacket 3 includes steel pipe piles 6, a connecting system 7, and a delivery pipe 8. The bottom of the steel pipe piles 6 is vertically fixed in the rock layer below the seabed. A gravel fill layer 1 for leveling the seabed surface of the jacket 3 is provided at the bottom of the steel pipe piles 6. Counterweight concrete 2 for increasing the weight and stability of the jacket 3 is provided at the bottom of the steel pipe piles 6 and the gravel fill layer 1. The delivery pipe 8 is installed inside the steel pipe piles 6 for pumping concrete and pouring the counterweight concrete 2 at the bottom of the jacket 3. The steel truss 5 is the superstructure, and a top support 4 is provided between the top of the jacket 3 and the bottom of the steel truss 5 as a force transmission structure. A single set of jacket 3 consists of three steel pipe piles 6 connected by the connecting system 7 to form a triangular frame structure.

[0017] The counterweight concrete 2 at the bottom of the jacket 3 is grade C30 and is a cuboid structure with dimensions of 9000*3000*9000mm.

[0018] Steel truss 5 is welded from HN900*300 and HM588*300 steel sections.

[0019] The diameter of the steel pipe pile 6 is 2400mm and the wall thickness is 28mm, and the diameter of the connecting system 7 is 800mm and the wall thickness is 12mm.

[0020] The top support 4 is made of steel plates of Q235B material spliced ​​together.

[0021] A construction method for a prefabricated steel platform under deep-water bare rock conditions, the specific steps of which are as follows: Step 1: Fill the seabed with gravel to level the surface, obtaining gravel fill layer 1: A. Use GPS positioning to determine the leveling range of the guide frame 3; B. Within the leveling area, crushed stones are dumped to treat the uneven original seabed surface so that the leveled seabed surface reaches the design elevation. Step 2: Fabrication and transportation of the jacket structure 3 to the pier location for placement. A. Assemble and process the three steel pipe piles 6 and multiple sets of connecting systems 7 into a whole guide frame 3 in the factory; B. The top support 4 of the guide frame 3 is processed and installed in the factory, and the top support 4 together with the guide frame 3 is hoisted and lowered as a whole. C. After passing the inspection, the processed jacket structure 3 will be stored as a whole on a transport ship using a large floating crane and transported to the construction area. Step 3: Precisely position and lower the catheter stent 3. A. Use a large floating crane to lift a single set of jacket structure 3 from the transport ship and lower it to the pier location. Use GPS for precise positioning to assist in lowering the jacket structure 3 to the designed position on the seabed. Step 4: Pouring counterweight concrete 2 A. Install a template at the bottom of the jacket 3 in advance, and pump concrete into the template through the delivery pipe 8 inside the steel pipe pile 6 to complete the pouring of the counterweight concrete 2 at the bottom of the jacket 3. Step 5: Installation of remaining guide frame 3 and pouring of counterweight concrete 2 A. Repeat steps two and three to complete the installation of the remaining duct frame 3; B. Repeat step four to complete the pouring of the remaining counterweight concrete 2; Step Six: Installation and Lowering of the Truss Platform A. Steel truss 5 is processed in the processing plant. After processing, it is transported to the construction area by a large transport ship and anchored for positioning. B. Use a large floating crane to lift and install the steel truss 5 onto the top support 4 of the jacket frame 3, and adjust the elevation; C. Connect the steel truss 5 with the top support 4 to form an integrated platform, and then proceed with the main construction project.

[0022] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A prefabricated steel platform under deepwater bare rock conditions, characterized by: It includes a gravel filling layer, counterweight concrete, a conductor frame, a top support, and a steel truss, wherein the conductor frame includes a steel pipe pile, a connection system, and a delivery pipe; the bottom of the steel pipe pile is vertically fixed in the rock layer below the seabed, and a gravel filling layer for leveling the seabed surface of the conductor frame is provided at the bottom of the steel pipe pile; counterweight concrete for increasing the weight of the conductor frame and thus increasing the stability of the conductor frame is provided at the bottom of the steel pipe pile and the gravel filling layer; the delivery pipe is arranged in the steel pipe pile for pumping concrete and pouring the counterweight concrete at the bottom of the conductor frame; the steel truss is the upper structure, and a top support is provided between the top of the conductor frame and the bottom of the steel truss as a force transmission structure; a single set of conductor frames is connected into a tripod structure by three steel pipe piles through a connection system.

2. The deepwater bare rock fabricated steel platform according to claim 1, characterized in that: The counterweight concrete at the bottom of the conductor rack is graded C30 and is a rectangular structure with dimensions of 9000*3000*9000mm.

3. The deepwater bare rock fabricated steel platform according to claim 1, characterized in that: The steel truss is welded from HN900*300 and HM588*300 steel.

4. The deepwater bare rock fabricated steel platform according to claim 1, characterized in that: The diameter of the steel pipe pile is 2400mm and the wall thickness is 28mm, the diameter of the connecting system is 800mm and the wall thickness is 12mm.

5. The deepwater bare rock fabricated steel platform according to claim 1, characterized in that: The top support is made of Q235B steel plates.

6. A construction method for an assembled steel platform under deepwater bare rock conditions, characterized in that: The specific steps are as follows: Step 1: Fill the seabed with gravel to level the seabed surface and obtain a gravel filling layer: A. Use GPS positioning to determine the leveling range of the conductor frame; B. Within the leveling range, fill the uneven seabed with gravel to make the seabed reach the designed elevation after leveling; Step 2: Processing and transporting the jacket to the pier for implantation A. Assemble three steel pipe piles and multiple sets of connecting ties in the factory to form a jacket frame; B. The top support of the conductor rack is processed and installed in the factory, and the top support and the conductor rack are hoisted and lowered as a whole; C. After passing the inspection, a large floating crane is used to store the processed jacket as a whole on a transport ship and transport it to the construction area; Step 3: Precise positioning and lowering of the catheter rack A. Use a large floating crane to hoist a single set of jackets from the transport ship and lower them to the pier. Use GPS for precise positioning to assist the jackets in lowering to the designed position on the seabed. Step 4: Pouring counterweight concrete A. Pre-install the template at the bottom of the jacket, pump concrete into the template through the delivery pipe in the steel pipe pile, and complete the pouring of the counterweight concrete at the bottom of the jacket; Step 5: Installation of the remaining conductor racks and pouring of counterweight concrete A. Repeat steps 2 and 3 to complete the installation of the remaining conductor racks; B. Repeat step 4 to complete the pouring of the remaining counterweight concrete; Step 6: Install and lower the truss platform A. The steel trusses are processed in the processing plant. After processing, they are transported to the construction area by large transport ships and anchored; B. Use a large floating crane to hoist the steel truss and install it on the top support of the conductor rack, and adjust the elevation; C. Connect the steel trusses and the top support to form an overall platform and then start the main construction.

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