Large-size cofferdam ring beam structure and installation and construction method thereof

Abstract

The invention discloses a large-size cofferdam ring beam structure and an installation and construction method thereof. The large-size cofferdam ring beam structure comprises a first ring beam structure, a second ring beam structure, a third ring beam structure and a fourth ring beam structure which are sequentially arranged on the inner side of a cofferdam steel sheet pile from top to bottom. The ring beam structure is composed of inner ring beams, short inclined struts, long inclined struts and inner straight struts, the inner ring beams are sequentially connected end to end to form a rectangular ring beam, the short inclined struts are arranged at the four corners of the rectangular ring beam, the long inclined struts are arranged on the rear sides of the short inclined struts, and the two ends of the short inclined struts and the two ends of the long inclined struts are connected with the adjacent long edges and short edges of the rectangular ring beam respectively. The inner straight support is transversely arranged in the middle of the rectangular ring beam and connected with the long edge of the rectangular ring beam. The ring beam structure is suitable for cofferdam construction of large-size steel sheet piles under the large depth, and sufficient fixing and supporting acting force can be provided for the large-size steel sheet piles through the multiple layers of ring beam structures so as to meet the requirements for strength, rigidity and stability of the cofferdam; and the steel sheet pile inserting and driving construction quality is guaranteed through guiding of the lowered ring beam structure.

Description

Technical Field

[0001] The invention relates to the technical field of cofferdam construction, in particular to a large-size cofferdam ring beam structure and an installation construction method thereof. Background Art

[0002] With the development of society, road and bridge projects, as basic infrastructure projects, are an important part of urban transportation networks. Highway bridges and viaducts often use bridge piers as supports. Therefore, the construction of bridge piers is one of the keys to road and bridge projects. In water-related bridge projects, cofferdam construction is often required, and a certain area is built in the water-related area for the construction of pier foundations. There are many traditional cofferdam construction methods. In the actual construction process, in addition to using conventional cofferdam structures and cofferdam construction processes, it is also necessary to comprehensively consider the hydrogeological conditions of the construction area, and make targeted improvements and optimizations to the cofferdam structure and cofferdam construction process methods to ensure the smooth progress of cofferdam construction. In the construction of steel sheet pile cofferdams, since the water and soil pressure on the outside of the cofferdam is mainly borne by the steel sheet piles and the ring beam structure, in the construction of some large-scale deep-water steel sheet pile cofferdams, the existing cofferdam ring beam structure is difficult to meet the structural strength and construction requirements of the cofferdam construction. After determining the type of steel sheet pile structure, only improvements and optimizations can be made on the cofferdam ring beam structure to better meet the construction requirements of large-scale deep-water steel sheet pile cofferdams. Summary of the invention

[0003] In view of the above problems, the present invention provides a large-size cofferdam ring beam structure, comprising a first ring beam structure, a second ring beam structure, a third ring beam structure and a fourth ring beam structure which are arranged in sequence from top to bottom on the inner side of the cofferdam steel sheet piles, the first ring beam structure, the second ring beam structure, the third ring beam structure and the fourth ring beam structure are arranged at different depths and are connected and fixed to the cofferdam steel sheet piles to form an inner support; the first ring beam structure, the second ring beam structure, the third ring beam structure and the fourth ring beam structure are respectively composed of an inner ring beam, a short diagonal brace, a long diagonal brace and an inner straight brace, the inner ring beams are connected end to end in sequence to form a rectangular ring beam, the short diagonal braces are respectively arranged at the four corners of the rectangular ring beam, the long diagonal brace is arranged on the rear side of the short diagonal brace, the two ends of the short diagonal brace and the long diagonal brace are respectively connected to the adjacent long sides and short sides of the rectangular ring beam, and the inner straight brace is horizontally arranged in the middle of the rectangular ring beam to connect the long sides of the rectangular ring beam.

[0004] As a further illustration of the present invention, the inner ring beam of the first ring beam structure adopts double-pieced I45a I-beams, and the short diagonal braces adopt Diagonal tube, long diagonal brace Inclined tube, inner straight support Steel pipe.

[0005] Furthermore, the inner ring beam of the second ring beam structure adopts 2HN600×200 steel, the short diagonal brace adopts 2HN600×200 steel, and the long diagonal brace adopts Inclined tube, inner straight support Steel pipe.

[0006] Furthermore, the inner ring beam of the third ring beam structure adopts 3HN600×200 steel, the short diagonal brace adopts 3HN600×200 steel, and the long diagonal brace adopts Inclined tube, inner straight support Steel pipe, the structure and profile of the fourth ring beam structure are the same as those of the third ring beam structure.

[0007] Furthermore, the short diagonal brace also includes connecting steel sections arranged on both sides of the end portions, and the connecting steel sections are made of double-pieced I45a I-beams, which are used to increase the connecting support effect between the short diagonal brace and the inner ring beam.

[0008] Furthermore, the inner straight support further comprises connecting supports arranged on both sides of the end, and the connecting supports are The inclined tube is used to increase the connection support effect between the inner straight support and the inner ring beam.

[0009] On the other hand, the present invention also provides a large-size cofferdam ring beam structure installation construction method, which comprises the following steps:

[0010] S1, using the steel casing of the cofferdam structure to install the steel casing bracket, and installing a lowering system on the steel casing bracket;

[0011] S2, assembling the fourth ring beam structure on the operating platform, and using the lowering system to lower the assembled fourth ring beam structure to a position below the cap elevation +4.5m;

[0012] S3, assembling the third ring beam structure on the operating platform, and using the lowering system to lower the assembled third ring beam structure to a position about +6m above the cap elevation;

[0013] S4, assembling the second ring beam structure and the first ring beam structure on the operating platform, connecting the first ring beam structure and the second ring beam structure into a whole, and lowering the connected first ring beam structure and the second ring beam structure to the designed elevation position by using the lowering system;

[0014] S5, installing the first ring beam corbel to complete the sealing of the first ring beam structure; installing the second ring beam corbel to complete the sealing of the second ring beam structure;

[0015] S6, using the lowering system to continue to lower the fourth ring beam structure underwater to a position at an elevation of about +3.2m, lower the third ring beam structure underwater to its designed elevation, install the third ring beam corbel and complete the sealing of the third ring beam structure;

[0016] S7, using the lowering system to continue to lower the fourth ring beam structure underwater to its designed elevation position, installing the fourth ring beam corbel underwater, and caulking the fourth ring beam underwater.

[0017] Furthermore, the steps S5-S7 include operations such as pumping water, returning water and pumping sand.

[0018] Furthermore, in step S6, after the third ring beam structure is lowered to its designed elevation, a temporary diagonal brace is added to the second ring beam structure, and the temporary diagonal brace is removed when water returns to the second ring beam structure.

[0019] Furthermore, the fourth ring beam is sealed with concrete bags.

[0020] Beneficial effects of the present invention:

[0021] The ring beam structure of the present invention is suitable for the cofferdam construction of large-size steel sheet piles at a relatively large depth. On the one hand, the multi-layer ring beam structure can provide sufficient fixed supporting force for the large-size steel sheet piles to meet the strength, rigidity and stability requirements of the cofferdam; on the other hand, the pre-support method is adopted for construction, the ring beam structure is lowered to the designed elevation in advance, and the two ring beams above the riverbed are connected and combined into an overall frame and lowered, so as to achieve a stable installation and connection of the ring beam of the deep-water cofferdam and improve the installation and construction efficiency. At the same time, the lowered ring beam structure can be used as a guide bracket for the insertion of steel sheet piles to ensure the smooth insertion of the steel sheet piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a vertical view of a large-size cofferdam ring beam structure according to an embodiment of the present invention;

[0023] Figure 2 This is a side view of a large-size cofferdam ring beam structure according to an embodiment of the present invention;

[0024] Figure 3 It is a plan view of the large-size cofferdam ring beam structure according to an embodiment of the present invention.

[0025] Figure numerals: cofferdam steel sheet piles 1, first ring beam structure 2, second ring beam structure 3, third ring beam structure 4, fourth ring beam structure 5, inner ring beam 6, short diagonal brace 7, long diagonal brace 8, inner straight brace 9, connecting steel 10, connecting support 11, temporary diagonal brace 12, steel casing 13. DETAILED DESCRIPTION

[0026] Example:

[0027] The following is a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0028] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0029] As attached Figure 1-3 A large-size cofferdam ring beam structure shown includes a first ring beam structure 2, a second ring beam structure 3, a third ring beam structure 4 and a fourth ring beam structure 5 which are arranged on the inner side of a cofferdam steel sheet pile 1 from top to bottom, wherein the first ring beam structure, the second ring beam structure, the third ring beam structure and the fourth ring beam structure are arranged at different depths and are connected and fixed to the cofferdam steel sheet piles to form an inner support; the first ring beam structure, the second ring beam structure, the third ring beam structure and the fourth ring beam structure are respectively composed of an inner ring beam 6, a short diagonal brace 7, a long diagonal brace 8 and an inner straight brace 9, wherein the inner ring beams are connected end to end in sequence to form a rectangular ring beam, the short diagonal braces are respectively arranged at the four corners of the rectangular ring beam, the long diagonal brace is arranged on the rear side of the short diagonal brace, the two ends of the short diagonal brace and the long diagonal brace are respectively connected to the adjacent long sides and short sides of the rectangular ring beam, and the inner straight brace is horizontally arranged in the middle of the rectangular ring beam to connect the long sides of the rectangular ring beam. The ring beam structure of the present invention is suitable for the cofferdam construction of large-size steel sheet piles at a greater depth. On the one hand, the multi-layer ring beam structure can provide sufficient fixed supporting force for the large-size steel sheet piles to meet the cofferdam strength, rigidity and stability requirements.

[0030] As a specific implementation method, in this embodiment, the inner ring beam of the first ring beam structure adopts double-pieced I45a I-beams, and the short diagonal braces adopt Diagonal tube, long diagonal brace Inclined tube, inner straight support Steel pipe. As the component that directly contacts and connects the ring beam structure with the steel sheet piles, the inner ring beam specifically adopts double-piece steel. On the one hand, it meets the requirements in terms of structural strength. On the other hand, it is also convenient for the connection and fixation between the steel sheet piles and the ring beam structure, and between the inner ring beam and the short diagonal braces, the long diagonal braces and the inner straight braces. In actual applications, the first ring beam structure is at the top of the cofferdam and bears the least water and soil pressure. The double-piece I45a I-beam of the inner ring beam and the short diagonal braces are Oblique tube, long diagonal brace Diagonal tube and inner straight support The steel pipe can meet the requirements of strength, rigidity and stability of the first ring beam structure.

[0031] In this embodiment, the inner ring beam of the second ring beam structure is made of 2HN600×200 steel, the short diagonal brace is made of 2HN600×200 steel, and the long diagonal brace is made of Inclined tube, inner straight support As shown in the attached drawings, the second ring beam structure of this embodiment is deeper than the first ring beam structure, and the water and soil pressure it bears is relatively large. Compared with the first ring beam structure, it has higher strength requirements. In practical applications, the 2HN600×200 steel of the inner ring beam, the 2HN600×200 steel of the short diagonal brace, and the 2HN600×200 steel of the long diagonal brace are Diagonal tube and inner straight support The steel pipe can meet the requirements of the elevation depth shown in the embodiment for the strength, rigidity, stability and other aspects of the second ring beam structure.

[0032] In this embodiment, the inner ring beam of the third ring beam structure is made of 3HN600×200 steel, the short diagonal brace is made of 3HN600×200 steel, and the long diagonal brace is made of Inclined tube, inner straight support Steel pipe, the structure and profile of the fourth ring beam structure are the same as those of the third ring beam structure. Similarly, the elevation depth of the third ring beam structure and the fourth ring beam structure is deeper, and the water and soil pressure they bear is relatively large, and they have higher strength requirements than the second ring beam structure. In practical applications, through actual calculations and verifications, the third ring beam structure and the fourth ring beam structure of this embodiment can adopt the same structural design, specifically the 3HN600×200 steel of the inner ring beam, the 3HN600×200 steel of the short diagonal brace, and the 3HN600×200 steel of the long diagonal brace. Diagonal tube and inner straight support The steel pipes meet the requirements for strength, stiffness, stability and other aspects of the third ring beam structure and the fourth ring beam structure.

[0033] In a preferred embodiment, as shown in the accompanying drawings, the short diagonal brace in this embodiment also includes connecting steel sections 10 arranged on both sides of the end portions, and the connecting steel sections are made of double-pieced I45a I-beams, which are used to increase the connecting support effect between the short diagonal brace and the inner ring beam, and further increase the strength, rigidity and stability of the ring beam structure.

[0034] In a preferred embodiment, as shown in the accompanying drawings, the inner straight support in this embodiment further includes connecting supports 11 arranged on both sides of the end. The inclined tube is used to increase the connection support effect between the inner straight support and the inner ring beam, and further increase the strength, rigidity and stability of the ring beam structure.

[0035] Based on the specific structural design of the above-mentioned large-size cofferdam ring beam structure of the embodiment of the present invention, the present invention also provides a large-size cofferdam ring beam structure installation and construction method, which mainly includes the following steps:

[0036] S1, using the steel casing 13 of the cofferdam structure to install the steel casing bracket, and installing a lowering system on the steel casing bracket;

[0037] S2, assembling the fourth ring beam structure on the operating platform, and using the lowering system to lower the assembled fourth ring beam structure to a position below the cap elevation +4.5m;

[0038] S3, assembling the third ring beam structure on the operating platform, and using the lowering system to lower the assembled third ring beam structure to a position about +6m above the cap elevation;

[0039] S4, assembling the second ring beam structure and the first ring beam structure on the operating platform, connecting the first ring beam structure and the second ring beam structure into a whole, and lowering the connected first ring beam structure and the second ring beam structure to the designed elevation position by using the lowering system;

[0040] S5, installing the first ring beam corbel to complete the sealing of the first ring beam structure; installing the second ring beam corbel to complete the sealing of the second ring beam structure;

[0041] S6, using the lowering system to continue to lower the fourth ring beam structure underwater to a position at an elevation of about +3.2m, lower the third ring beam structure underwater to its designed elevation, install the third ring beam corbel and complete the sealing of the third ring beam structure;

[0042] S7, using the lowering system to continue to lower the fourth ring beam structure underwater to its designed elevation position, installing the fourth ring beam corbel underwater, and caulking the fourth ring beam underwater.

[0043] The present invention adopts the pre-support method for construction, lowers the ring beam structure to the designed elevation in advance, and connects and combines the two ring beams above the riverbed into an overall frame and lowers it, so as to achieve a stable installation and connection of the ring beam of the deepwater cofferdam and improve the installation and construction efficiency. At the same time, the lowered ring beam structure can be used as a guide bracket for the insertion of steel sheet piles to ensure the smooth insertion of the steel sheet piles.

[0044] It should be noted that steps S5-S7 described in this embodiment also include operations such as pumping water, returning water and pumping sand to ensure that the large-sized cofferdam ring beam structure can be installed smoothly and quickly.

[0045] In a preferred implementation manner, in the present embodiment, in the step S6, after the third ring beam structure is lowered to its design elevation, a temporary diagonal brace 12 is added to the second ring beam structure, and the temporary diagonal brace is removed when water returns to the second ring beam structure.

[0046] Specifically and feasiblely, in this embodiment, the fourth ring beam is sealed with concrete bags.

[0047] Thus, in practical applications, the main construction steps of the large-size cofferdam ring beam structure of this embodiment are as follows:

[0048] First, set up the operating platform, assemble and lower the fourth ring beam to below +4.5m → assemble and lower the third ring beam to +6m elevation (make corresponding changes according to the fourth ring beam, not higher than +6.3m) → assemble the second ring beam → assemble the first ring beam and then connect the first and second ring beams into a whole and lower them to the designed elevation → use 80-100cm diameter spiral drill to drill holes to -7.0m-insert steel sheet piles to -5.3m (control at not less than -5.3m) → install the first ring beam bracket → seal the first ring beam → pump water to +6.0m elevation → seal the second ring beam and install the second ring beam bracket → open the valve to return water to the water balance inside and outside the cofferdam → pump sand to +2.5 m (and no more than +2m) → lower the fourth ring beam underwater to an elevation of about +3.2m → lower the third ring beam underwater to an elevation of +4.5m (design elevation) → pump water to +6.5m → add temporary diagonal support to the second ring beam → continue pumping water to +4.0m → install corbels and plug the seams on the third ring beam → open the connecting valve to return water to the water balance inside and outside the cofferdam (when the water returns to the bottom of the second ring beam, the temporary support of the second ring beam needs to be removed) → pump sand to an elevation of -0.74m → lower the fourth ring beam underwater to +0.5m (design elevation), and install corbels underwater → plug the seams of the fourth ring beam with concrete bags underwater → complete the installation of the large-size cofferdam ring beam structure.

[0049] In addition, in the subsequent cofferdam construction process of the present invention, the ring beam structure of the present invention can be used as a guide bracket for the insertion of steel sheet piles to ensure the smooth progress of the insertion of steel sheet piles.

[0050] The above only describes the preferred embodiments of the present invention, but it cannot be understood as limiting the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to be changed. In short, all changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

Claims

1. A large-size cofferdam ring beam structure, characterized in that: It includes a first ring beam structure, a second ring beam structure, a third ring beam structure and a fourth ring beam structure which are arranged on the inner side of the cofferdam steel sheet piles from top to bottom, the first ring beam structure, the second ring beam structure, the third ring beam structure and the fourth ring beam structure are arranged at different depths and are connected and fixed to the cofferdam steel sheet piles to form an inner support; the first ring beam structure, the second ring beam structure, the third ring beam structure and the fourth ring beam structure are respectively composed of an inner ring beam, a short diagonal brace, a long diagonal brace and an inner straight brace, the inner ring beam is connected end to end in sequence to form a rectangular ring beam, the short diagonal braces are respectively arranged at the four corners of the rectangular ring beam, the long diagonal brace is arranged on the rear side of the short diagonal brace, the two ends of the short diagonal brace and the long diagonal brace are respectively connected to the adjacent long sides and short sides of the rectangular ring beam, and the inner straight brace is horizontally arranged in the middle of the rectangular ring beam to connect the long sides of the rectangular ring beam.

2. The large-size cofferdam ring beam structure according to claim 1 is characterized in that: The inner ring beam of the first ring beam structure adopts double-pieced I45a I-beams, the short diagonal braces adopt φ630×8mm diagonal tubes, the long diagonal braces adopt φ630×8mm diagonal tubes, and the inner straight braces adopt φ820×10mm steel tubes.

3. The large-size cofferdam ring beam structure according to claim 1 is characterized in that: The inner ring beam of the second ring beam structure adopts 2HN600×200 steel, the short diagonal brace adopts 2HN600×200 steel, the long diagonal brace adopts φ820×10mm diagonal tube, and the inner straight brace adopts φ1020×10mm steel tube.

4. The large-size cofferdam ring beam structure according to claim 1 is characterized in that: The inner ring beam of the third ring beam structure adopts 3HN600×200 steel, the short diagonal brace adopts 3HN600×200 steel, the long diagonal brace adopts φ820×10mm diagonal tube, and the inner straight brace adopts φ1020×10mm steel tube. The structure and profile of the fourth ring beam structure are the same as those of the third ring beam structure.

5. The large-size cofferdam ring beam structure according to claim 1 is characterized in that: The short diagonal brace also includes connecting steel sections arranged on both sides of the end portions, and the connecting steel sections are made of double-pieced I45a I-beams, which are used to increase the connecting support effect between the short diagonal brace and the inner ring beam.

6. The large-size cofferdam ring beam structure according to claim 1 is characterized in that: The inner straight support also includes connecting supports arranged on both sides of the end, and the connecting supports adopt φ630×8mm inclined tubes to increase the connecting support effect between the inner straight support and the inner ring beam.

7. A method for installing and constructing a large-size cofferdam ring beam structure, characterized in that: The following steps are involved: S1, using the steel casing of the cofferdam structure to install the steel casing bracket, and installing a lowering system on the steel casing bracket; S2, assembling the fourth ring beam structure on the operating platform, and using the lowering system to lower the assembled fourth ring beam structure to a position below the cap elevation +4.5m; S3, assembling the third ring beam structure on the operating platform, and using the lowering system to lower the assembled third ring beam structure to a position about +6m above the cap elevation; S4, assembling the second ring beam structure and the first ring beam structure on the operating platform, connecting the first ring beam structure and the second ring beam structure into a whole, and lowering the connected first ring beam structure and the second ring beam structure to the designed elevation position by using the lowering system; S5, installing the first ring beam corbel to complete the sealing of the first ring beam structure; installing the second ring beam corbel to complete the sealing of the second ring beam structure; S6, using the lowering system to continue to lower the fourth ring beam structure underwater to a position at an elevation of about +3.2m, lower the third ring beam structure underwater to its designed elevation, install the third ring beam corbel and complete the sealing of the third ring beam structure; S7, using the lowering system to continue to lower the fourth ring beam structure underwater to its designed elevation position, installing the fourth ring beam corbel underwater, and caulking the fourth ring beam underwater.

8. The installation construction method of the large-size cofferdam ring beam structure according to claim 7 is characterized in that: The steps S5-S7 include operations such as pumping water, returning water and pumping sand.

9. The installation construction method of the large-size cofferdam ring beam structure according to claim 7 is characterized in that: In the step S6, after the third ring beam structure is lowered to its designed elevation, a temporary diagonal brace is added to the second ring beam structure, and the temporary diagonal brace is removed when water returns to the second ring beam structure.

10. The large-size cofferdam ring beam structure installation construction method according to claim 7 is characterized in that: The fourth ring beam is sealed with concrete bags.

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