Large cantilever cofferdam anti-floating device

Abstract

According to the anti-floating device for the large cantilever cofferdam in water, the construction difficulty of the large cantilever cofferdam can be reduced when a bearing platform is constructed, the efficiency is improved, and the period is shortened. The device comprises steel pipe piles, main cross beams, anti-floating tie bars, bottom sealing concrete and the like. A pile casing is arranged on the peripheral surface of the pile foundation; each side mold comprises a bottom sealing side plate, angle steel, a bearing platform side plate and a bearing platform bottom plate; the bottom sealing side plate is vertically arranged on the upper surface of the bearing platform bottom plate and forms the outline of a cofferdam in a surrounding mode. The angle steel is connected to the inner side face of the bottom sealing side plate in the horizontal direction. The bearing platform side plate is detachably connected to the upper surface of the bottom sealing side plate; a plurality of horizontal tie bars are connected between the bottom sealing side plate and the circumferential face of the pile casing, and the steel pipe piles are arranged on the two sides of the large cantilever in a driving mode and fixedly welded to the main cross beam. The main cross beams are welded on the steel pipe piles, and the anti-floating tie bars are arranged on the main cross beams on the inner sides of the steel pipe piles.

Description

Technical Field

[0001] The utility model relates to the technical field of cofferdam construction, in particular to an anti-floating device for a large cantilever cofferdam. Background Technique

[0002] A cofferdam is a temporary enclosure structure built for the construction of permanent water conservancy facilities in water conservancy project construction. The function of the cofferdam is to prevent water and soil from entering the construction location of the building, so as to drain water, excavate the foundation pit, build the building, etc. inside the cofferdam. Generally, it is mainly used in hydraulic engineering. When the cantilever of the cofferdam bottom seal is small, the conventional construction can be adopted for the bottom seal floor slab.

[0003] With the continuous and rapid development of China's highway and bridge industry over the years, more and more bridges are built across large rivers, seas and other waters. In the related existing technologies, the bridge span form in the non-navigable hole area of the sea bridge is usually designed as a whole-hole precast box girder, with engineering characteristics such as large caisson size, large cantilever, and deep water at the pier position. If the ordinary lifting caisson cofferdam construction is adopted, when the cantilever distance of the caisson is large, the conventional concrete bottom seal cannot resist the buoyancy of water on the bottom of the cofferdam during the high water level period of construction, resulting in the damage of the cofferdam structure and the inability to complete the caisson construction. Content of the Utility Model

[0004] (1) Technical Problems to be Solved

[0005] To solve the above problems of the existing technology, the utility model provides.

[0006] (2) Technical Solutions

[0007] To achieve the above purpose, the main technical solutions adopted by the utility model include:

[0008] An anti-floating device for a large cantilever cofferdam, including pile foundations, a bottom plate and side forms;

[0009] The pile foundations are vertically arranged, and casings are sleeved on the pile foundations;

[0010] The bottom plate is laid within the range of the cofferdam caisson, a crushed stone layer is laid on the surface of the bottom plate, and reserved holes corresponding to the pile foundations are opened on the bottom plate,

[0011] The side forms include bottom seal side plates, angle steels and caisson side plates. A plurality of the bottom seal side plates are vertically arranged on the upper surface of the crushed stone layer and enclose the outline of the cofferdam. The angle steels are horizontally connected to the inner side surfaces of the bottom seal side plates, and the caisson side plates are detachably connected to the upper surfaces of the bottom seal side plates.

[0012] Preferably, it further includes a bottom seal concrete layer, which is laid on the bottom plate and is located within the cofferdam outline formed by the bottom seal side plates.

[0013] Preferably, it further includes steel pipe piles, main cross beams and anti-floating tie bars;

[0014] There are two steel pipe piles, which are symmetrically arranged front and back under the cantilever of the cofferdam;

[0015] The main cross beam is welded on the top of the steel pipe pile. A number of anti-floating tie bars are arranged on one side of the main cross beam close to the steel pipe pile. The anti-floating tie bars are connected to the main cross beam and penetrate into the bottom-sealing concrete layer, and are cast integrally with the bottom-sealing concrete layer.

[0016] Preferably, it further includes horizontal tie bars. There are multiple horizontal tie bars, and the multiple horizontal tie bars are arranged between the circumferential surfaces of the bottom-sealing side plate and the casing.

[0017] Preferably, sponge rubber is pasted between the joints of the bottom-sealing side plate and the pile cap side plate.

[0018] Preferably, the bottom-sealing concrete layer includes a bottom-sealing steel bar mesh and bottom-sealing shear bars.

[0019] (III) Beneficial effects

[0020] The beneficial effects of the present utility model are as follows:

[0021] 1. By designing the side formwork of the cofferdam into segmented sections and the cofferdam as a prefabricated type as a whole, the transportation cost and time cost during the installation of the side formwork can be reduced. Moreover, the side formwork can be reused repeatedly, which can greatly reduce the input cost of the formwork, achieving the purpose of simplifying the process and saving costs;

[0022] 2. Using precision-rolled steel to lift the bottom and laying a steel bottom formwork facilitates the rapid assembly of the bottom-sealing side plate. And when assembling the pile cap side plate subsequently, the bottom-sealing concrete has hardened and the working surface is fixed. Assembling large pieces of the pile cap side plate will be safer and the construction risk will be reduced. Moreover, the pile cap side plate can also be customized with different heights according to different engineering requirements;

[0023] 3. The unique angle steel design on the inner side of the bottom-sealing side plate can achieve the vertical limit of the bottom-sealing side plate and the bottom-sealing concrete, improve the connection strength of the bottom-sealing side plate, and further ensure construction safety;

[0024] 4. To resist the buoyancy of seawater after the installation of the large cantilever part of the cofferdam, steel pipe piles are driven outside the cantilever section and welded and fixed to the main cross beam. Anti-floating tie bars are used to connect the main cross beam and penetrate into the bottom-sealing concrete. The part extending into the framework is cast integrally with the bottom-sealing concrete. The seawater buoyancy is conducted to the anti-floating tie bars, cross beam and steel pipe piles through the bottom framework concrete, and the anti-pulling force of the steel pipe piles is used to resist the buoyancy of the large cantilever section, so as to achieve the purpose of safely constructing the pile cap.

[0025] 5. The structure of the present utility model can enable continuous and rapid operation, reduce safety risks, shorten the total construction period, and can significantly reduce the investment, management fees and other fixed expenses of the bottom-sealing reinforced concrete, creating greater economic benefits for the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural view of a large cantilever cofferdam anti-floating device Figure 1 ;

[0027] Figure 2 is a schematic structural view of a large cantilever cofferdam anti-floating device Figure 2 ;

[0028] Figure 3 is a schematic structural view of a large cantilever cofferdam anti-floating device Figure 3 ;

[0029] Figure 4 is a schematic structural view of a large cantilever cofferdam anti-floating device Figure 4 ;

[0030] Figure 5 is a schematic structural view of a large cantilever cofferdam anti-floating device Figure 5 ;

[0031] Figure 6 is a schematic structural view of a large cantilever cofferdam anti-floating device Figure 6 。

[0032] DESCRIPTION OF THE REFERENCE NUMERALS:

[0033] 1. Pile foundation;

[0034] 2. Bottom slab;

[0035] 3. Side formwork; 31. Bottom-sealing side plate; 32. Angle steel; 33. Cap side plate; 34. Sponge rubber;

[0036] 4. Horizontal tie bar;

[0037] 5. Steel pipe pile;

[0038] 6. Main cross beam;

[0039] 7. Anti-floating tie bar;

[0040] 8. Bottom-sealing concrete layer;

[0041] 9. Casing. DETAILED IMPLEMENTATION MANNER

[0042] In order to better explain the present utility model for easy understanding, the present utility model will be described in detail below with reference to the accompanying drawings through specific implementation manners.

[0043] Please refer to Figures 1 to 6, the present utility model provides a large cantilever cofferdam anti-floating device, which includes pile foundations, a bottom plate and side forms;

[0044] The pile foundations are vertically arranged, and casing pipes are sleeved on the pile foundations;

[0045] The bottom plate is laid within the range of the cofferdam bearing platform. A layer of crushed stones is laid on the surface of the bottom plate, and reserved holes corresponding to the pile foundations are opened on the bottom plate.

[0046] The side forms include bottom-sealing side plates, angle steels and bearing platform side plates. There are multiple bottom-sealing side plates, and the multiple bottom-sealing side plates are vertically arranged on the upper surface of the crushed stone layer and enclose the contour of the cofferdam. The angle steels are horizontally connected to the inner side surfaces of the bottom-sealing side plates, and the bearing platform side plates are detachably connected to the upper surfaces of the bottom-sealing side plates;

[0047] In this embodiment, it further includes a bottom-sealing concrete layer, which is laid on the bottom plate and is located within the cofferdam contour formed by the bottom-sealing side plates.

[0048] In this embodiment, it further includes steel pipe piles, main cross beams and anti-floating tie bars;

[0049] There are two steel pipe piles, which are symmetrically arranged front and back under the cofferdam cantilever;

[0050] The main cross beam is welded on the top of the steel pipe piles. A number of anti-floating tie bars are arranged on the side of the main cross beam close to the steel pipe piles. The anti-floating tie bars are connected to the main cross beam and penetrate into the bottom-sealing concrete layer, and are cast integrally with the bottom-sealing concrete layer.

[0051] In this embodiment, it further includes horizontal tie bars. There are multiple horizontal tie bars, and the multiple horizontal tie bars are arranged between the circumferential surfaces of the bottom-sealing side plates and the casing pipes.

[0052] In this embodiment, sponge rubbers are pasted between the joints of the bottom-sealing side plates and the bearing platform side plates.

[0053] In this embodiment, the bottom-sealing concrete layer includes a bottom-sealing steel bar mesh and bottom-sealing shear bars;

[0054] Both sides of the angle steel are welded and fixed to the inner side surface of the bottom-sealing side plate, and its corners point away from the bottom-sealing side plate. When the bottom-sealing concrete layer is poured, the angle steel plays a role of vertical limit between the bottom-sealing side plate and the bottom-sealing concrete layer, so that the bottom-sealing side plate can support the bearing platform side plate more stably;

[0055] The bearing platform side plates are all large integral steel forms, and the side forms composed of the bottom-sealing side plates and the bearing platform side plates can be recycled;

[0056] Sponge rubber is installed between the bottom plate and the bottom sealing side plates, between the bottom sealing side plates themselves, and between the bottom sealing side plates and the bearing platform side plates. After being compressed, the sponge rubber is about 2 mm thick, playing a strong sealing role to prevent the cofferdam from leaking.

[0057] The horizontal tie bars penetrate through to the outer side of the bottom sealing side plates and are locked with nuts, so that it is easy to remove the bottom sealing side plates after the construction of the bearing platform is completed.

[0058] The bottom sealing concrete is composed of a bottom sealing steel bar mesh and bottom sealing shear bars, which are used to improve the strength of the poured bottom sealing concrete;

[0059] The buoyancy of the seawater is conducted through the bottom sealing concrete to the anti-floating tie bars, cross beams, and steel pipe piles, and the uplift force of the steel pipe piles is used to resist the buoyancy of the large cantilever section.

[0060] Reference Figures 1 to 2 As shown, the construction process of the present utility model is as follows:

[0061] Step 1, refer to Figure 2 , drive the pile foundations; after the construction of the pile foundations is completed, remove the construction operation platform, drive steel pipe piles outside the large cantilever, weld temporary bottom plate installation brackets on the steel casing at low water level, lay the bottom main cross beams and the hanging bottom system, cut a notch at the top of the driven steel pipe piles to install the main cross beams and weld the main cross beams to the top of the steel pipe piles, and install anti-floating tie bars on the main cross beams within the range of the bottom plate;

[0062] Step 2, refer to Figure 3 , at low water level, weld bottom sealing shear bars on the circumferential surface of the casing of the pile foundation, install the bottom sealing steel bar mesh and bottom sealing side plates, and weld horizontal tie bars on the outside of the casing to connect with the bottom sealing side plates, and weld angle steels on the inner side surface of the bottom sealing side plates; when installing the bottom sealing side plates, assemble each bottom sealing side plate in the order of short sides first and then long sides, and pass the horizontal tie bars through the designed hole positions on the bottom sealing side plates and tighten them;

[0063] Step 3, refer to Figure 4 , at low water level, pump out the accumulated water between the bottom sealing side plates and the bottom plate, and pour the bottom sealing concrete;

[0064] Step 4, refer to Figure 5 , when the strength of the bottom sealing concrete meets the requirements, at low water level, remove the hanging system and the bottom plate, cut off the excess casing to the design elevation, and break the pile head manually with the assistance of a pneumatic pick;

[0065] Step 5, refer to Figure 6 , at low water level, assemble the bearing platform side plates on each bottom sealing side plate in the order of short sides first and then long sides. After the assembly of the bearing platform side plates is completed, install the internal supports and cross braces inside the cofferdam; after the assembly of the bearing platform side plates is completed, carry out the construction of the bearing platform: clean the base surface, pump out the water, carry out the construction of the embedded bearing platform steel bars and the steel bars of the first section of the pier shaft, and pour the bearing platform concrete.

[0066] In addition, sponge rubber can be added at each joint position when assembling the bottom sealing side plate and the bearing platform side plate to improve the sealing effect.

[0067] When the construction of the first pier body is completed and the bearing platform concrete reaches more than 70% of the design strength, the side formwork can be removed. First, release the internal support inside the cofferdam, and then remove the bearing platform side plate and the bottom sealing side plate in sequence. After the side formwork is removed, it can be reused for the cofferdam construction at other positions.

[0068] Through the above solution, in the utility model, the side formwork of the cofferdam is designed in segmented sections, and the cofferdam is designed as an assembled type as a whole, which can reduce the transportation cost and time cost when installing the side formwork. Moreover, the side formwork can be reused repeatedly, which can greatly reduce the input cost of the formwork, achieving the purpose of simplifying the process and saving costs. Using the rolled steel for hoisting the bottom plate as the bottom formwork for construction is convenient for the rapid assembly of the bottom sealing side plate. And when assembling the bearing platform side plate subsequently, the bottom sealing concrete has hardened and the working surface is fixed, so the assembly of large-sized bearing platform side plates will be safer and the construction risk will be reduced. Also, the bearing platform side plates can be customized with different heights according to different engineering requirements. The unique angle steel design on the inner side of the bottom sealing side plate can realize the vertical limit of the bottom sealing side plate and the bottom sealing concrete, improve the connection strength of the bottom sealing side plate, and further ensure the construction safety. The buoyancy of seawater is conducted to the anti-floating tension bars, cross beams, and steel pipe piles through the bottom framework concrete, and the buoyancy of the large cantilever section is resisted by the uplift force of the steel pipe piles. Using the structure of the utility model can form continuous and rapid operation, reduce the construction cost, shorten the total construction period, can greatly reduce the mechanical cost, management cost and other fixed expenditures of the project, and can create greater economic benefits for the project.

[0069] The circuits, electronic components and modules involved are all prior arts, which can be fully realized by those skilled in the art without further elaboration. The content protected by the utility model does not involve the improvement of software and methods either.

[0070] The above are only the embodiments of the utility model, and do not limit the patent scope of the utility model accordingly. All equivalent transformations made by using the content of the specification and drawings of the utility model, or directly or indirectly applied in the relevant technical fields, are equally included in the patent protection scope of the utility model.

[0071] In addition, it should be understood that although this specification is described according to the implementation manners, not every implementation manner only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation manners that can be understood by those skilled in the art.

Claims

1. A large cantilever cofferdam anti-floating device, characterized in that, It includes pile foundations, a bottom slab, a concrete sealing layer, side formworks, steel pipe piles, main cross beams and anti-floating tension bars; The pile foundations are vertically arranged, and casing pipes are sleeved on the pile foundations; The bottom slab is laid within the cofferdam bearing platform range. A layer of crushed stones is laid on the surface of the bottom slab, and reserved holes corresponding to the pile foundations are formed in the bottom slab. The side formworks include bottom sealing side plates, angle steels and bearing platform side plates. A plurality of the bottom sealing side plates are provided, and the plurality of bottom sealing side plates are vertically arranged on the upper surface of the crushed stone layer and enclose the contour of the cofferdam. The angle steels are horizontally connected to the inner side surfaces of the bottom sealing side plates, and the bearing platform side plates are detachably connected to the upper surfaces of the bottom sealing side plates; The concrete sealing layer is laid on the bottom slab and is located within the cofferdam contour formed by the bottom sealing side plates; Two steel pipe piles are provided and are symmetrically arranged front and back under the cantilever of the cofferdam; The main cross beam is welded to the top of the steel pipe pile. A number of anti-floating tension bars are arranged on the side of the main cross beam close to the steel pipe pile. The anti-floating tension bars are connected to the main cross beam and penetrate into the concrete sealing layer to be integrally cast with the concrete sealing layer.

2. The anti-floating device for a large cantilever cofferdam according to claim 1, wherein It further includes horizontal tension bars. A plurality of the horizontal tension bars are provided, and the plurality of horizontal tension bars are arranged between the circumferential surfaces of the bottom sealing side plates and the casing pipes.

3. The anti-floating device for a large cantilever cofferdam according to claim 1, characterized in that, Sponge rubbers are pasted between the joints of the bottom sealing side plates and the bearing platform side plates.

4. The anti-floating device for a large cantilever cofferdam according to claim 1, characterized in that, The concrete sealing layer includes a bottom sealing steel bar mesh and bottom sealing shear bars.

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