Double-wall steel boxed cofferdam

Abstract

The utility model discloses a double-wall steel sleeve box cofferdam, which belongs to the field of civil engineering and comprises a double-wall steel sleeve box cofferdam body, an outer wall plate, an inner wall plate, a guide device, a partition plate, a compartment, a steel embedded column, a bottom compartment, diagonal bracings and a ring beam. According to the double-wall steel sleeve box cofferdam, in the water injection and mud suction sinking process, the guide device can accurately position the plane position of the cofferdam, and damage to the inner wall plate and the guide column of the cofferdam cannot be caused. The inner wall plate and the outer wall plate which are fixed through the steel embedded columns and the inner supports are stable in structure, so that the sinking operation process of the steel cofferdam is stable, convenient and easy to operate. In the sinking process of the double-wall steel cofferdam, a telescopic adjustable cofferdam guide structure is adopted, the sinking precision of the cofferdam can be effectively controlled, and plane deviation is reduced. Sludge suction sinking difficulty exists at four corners of the cofferdam in the sinking process after the double-wall steel cofferdam is implanted, and in order to guarantee straight sinking of the cofferdam, the mode that high-pressure water jet pipes are arranged at the four corners of the cofferdam to assist the cofferdam in sludge suction sinking is adopted.

Description

Technical Field

[0001] This invention relates to a construction equipment, and more particularly to a double-walled steel cofferdam. Background Technology

[0002] Depending on the construction and geological conditions, the water-retaining structures for deep-water bridge foundations come in various forms, including double-walled steel cofferdams, sheet pile cofferdams, and reinforced concrete cofferdams. A double-walled steel cofferdam serves as a water-retaining and soil-retaining structure for bridge abutment foundations, and also acts as a formwork for abutment construction. It is bottomless and open-topped, typically composed of cutting edges, inner and outer wall panels, bulkheads, vertical ribs, circumferential reinforcing plates, and reinforcing column sections. There are generally two construction methods for double-walled steel cofferdams: one is to float them to their final location as a whole, and the other is to assemble them in situ. The sinking of a double-walled steel cofferdam generally requires passing through the water flow layer and soil layer. Different sinking methods are used depending on the soil geological conditions. For sandy and gravelly strata, a suction pipe is generally used for mud suction sinking; for rock strata, blasting or impact methods are generally used. After the cofferdam sinks to the design position, underwater sealing concrete is poured to form a water-stopping and soil-retaining cofferdam. The steel sheet piles, through their own rigidity and tight interlocking, achieve water and soil retention in the deep foundation pit.

[0003] The existing double-walled steel cofferdam and its construction methods have the following disadvantages, which are particularly prominent in the construction of deep-water foundations and long-span bridge abutments: the guide wheels can cause some damage to the inner wall of the cofferdam, and the guiding effect is not ideal when the water is deep and the current is rapid; the method of using water pumps to replenish water into the cofferdam when dredging and sinking the cofferdam is cumbersome and inconvenient to control; the single-compartment pouring of counterweight concrete is cumbersome and cannot guarantee that the volume of concrete in each compartment is equal, which can easily cause the cofferdam to be unbalanced on one side. Summary of the Invention

[0004] To address the issues of sinking and positioning, and installation stability, of double-walled steel cofferdams, this invention provides a double-walled steel cofferdam.

[0005] To achieve the above technical solution, the present invention provides a double-walled steel cofferdam, comprising a double-walled steel cofferdam body composed of inner and outer wall panels and multiple guiding devices disposed on the inner side of the inner wall panel. Multiple vertical partitions are provided between the inner and outer wall panels, dividing the double-walled steel cofferdam body into multiple compartments. It also includes steel concealed columns disposed around the cofferdam, a bottom compartment disposed at the bottom of the middle of the cofferdam, and several sets of bracing in the middle of the cofferdam. The steel concealed columns connect adjacent inner and outer wall panels, and the bottom compartment and bracing connect symmetrically disposed inner wall panels. Several sets of ring beams are arranged around the inner wall panel, and inner supports are provided on the ring beams. The inner supports are fixed at both ends to the ring beams or at one end to the ring beams and at the other end to the bracing, so as to fix the inner wall panel.

[0006] Furthermore, the guiding device consists of a guiding base and a guiding mechanism mounted on the guiding base; the guiding base is fixed to the surface of the inner wall plate by a stiffening plate on the inner wall of the cofferdam.

[0007] Furthermore, the guiding mechanism includes a thrust box, a spiral telescopic rod, and a guide wheel. The thrust box has a through hole with threads on the inner wall of the through hole. The spiral telescopic rod passes through the through hole and connects to the guide wheel.

[0008] Furthermore, the inclination angle of the internal support is 45°.

[0009] Furthermore, the cross-section of the steel concealed column is rectangular.

[0010] Furthermore, several high-pressure water guns are installed on the two sides of the steel concealed column that are away from the inner and outer wall panels.

[0011] In summary, the present invention has the following advantages over the prior art:

[0012] The double-walled steel cofferdam provided by this invention allows for precise positioning of the cofferdam's planar location during the water injection and sludge suction sinking process, without damaging the inner wall panels or guide columns. The stable structure of the inner and outer wall panels, secured by concealed steel columns and internal supports, ensures a stable, convenient, and simple sinking operation for the steel cofferdam.

[0013] During the sinking process of the double-walled steel cofferdam, an adjustable cofferdam guide structure is used, which can effectively control the sinking accuracy of the cofferdam and reduce planar deviation.

[0014] During the sinking process after the double-walled steel cofferdam is placed on the bed, there will be difficulties in suctioning mud and sinking at the four corners of the cofferdam. In order to ensure that the cofferdam sinks straight, high-pressure water jet pipes are installed at the four corners of the cofferdam to assist in suctioning mud and sinking. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0016] Figure 1 This is a front view of a double-walled steel-cascade cofferdam.

[0017] Figure 2 This is a top view of a double-walled steel-cascade cofferdam;

[0018] Figure 3 This is a schematic diagram showing the use of the guide device;

[0019] Figure 4 This is a schematic diagram of the guiding device.

[0020] Figure 5This is a schematic diagram of the steel concealed column structure.

[0021] The above figures include the following reference numerals:

[0022] 1. Double-walled steel cofferdam body; 10. Outer wall panel; 11. Inner wall panel; 12. Partition plate; 13. Compartment; 14. Reinforcing plate of inner wall of cofferdam; 2. Guiding device; 20. Guiding base; 21. Guiding mechanism; 210. Thrust box; 211. Spiral telescopic rod; 212. Guide wheel; 3. Concealed steel column; 31. High-pressure water gun; 4. Ring beam; 5. Support; 6. Internal support; 7. Bottom compartment. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form may also include the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] See Figures 1 to 5 As shown, the present invention provides a double-walled steel cofferdam, including a double-walled steel cofferdam body 1 composed of an inner wall panel 11 and an outer wall panel 10, and multiple guide devices 2 disposed on the inner side of the inner wall panel 11. Multiple vertical partitions 12 are provided between the inner wall panel 11 and the outer wall panel 10, and the partitions 12 divide the double-walled steel cofferdam body 1 into multiple compartments 13. It also includes steel hidden columns disposed around the cofferdam, a bottom compartment 7 disposed at the bottom of the middle of the cofferdam, and several sets of bracing 5 disposed in the middle of the cofferdam. The steel hidden columns connect adjacent inner wall panels 11 and outer wall panels 10, and the bottom compartment 7 and bracing 5 connect symmetrically disposed inner wall panels 11. Several sets of ring beams 4 are provided around the inner wall panel 11, and inner supports 6 are provided on the ring beams 4. The inner supports 6 are fixed at both ends to the ring beams 4 or one end is fixed to the ring beams 4 and the other end is fixed to the bracing 5 to realize the fixation of the inner wall panel 11.

[0026] The actual operation process is as follows:

[0027] (1) Steel cofferdam assembly

[0028] The cofferdam is assembled in situ. After being transported to the pier location, it is assembled using a 150t crawler crane. A platform is erected for the first cofferdam section, positioned 1.5m above the water surface. Subsequent cofferdam section extensions are carried out on the first section, using a symmetrical assembly method.

[0029] Precautions for assembling cofferdams:

[0030] ① The support platform for assembling the bottom section of the cofferdam should be firm, and the top plane should be leveled; deformed steel components should be corrected before assembly;

[0031] ②Only after the trial assembly of the cofferdam side panels is qualified can the joints of the blocks be formally welded;

[0032] ③ The assembly of the cofferdam should be carried out symmetrically in different areas, and measurements should be taken and verified in a timely manner.

[0033] ④ When splicing, be sure to control the levelness of the horizontal ring plate.

[0034] ⑤ When lifting the cofferdam, it should be lifted from the designated position and should not be arbitrarily altered. Collisions should be avoided during lifting.

[0035] (2) Construction Inspection

[0036] In addition to meeting design requirements, all welds on the steel cofferdam should undergo a kerosene test after welding is completed and before launching. Apply lime water to the external welds of the shell, allow it to air dry, then apply kerosene to the corresponding internal welds. Visually inspect for seepage after 15 minutes. If seepage reaches the reverse side, remove that weld and re-weld it according to regulations.

[0037] During the placement of the double-walled steel cofferdam, the inner and outer wall panels 10, which are fixed by steel columns and inner supports 6, are structurally stable, making the sinking operation of the steel cofferdam stable, convenient, and simple.

[0038] As a preferred embodiment, the guiding device 2 consists of a guiding base 20 and a guiding mechanism 21 disposed on the guiding base 20; the guiding base 20 is fixed to the surface of the inner wall plate 11 by the inner wall stiffening plate 14 of the cofferdam.

[0039] As a preferred embodiment, the guide mechanism 21 includes a thrust box 210, a spiral telescopic rod 211, and a guide wheel 212. The thrust box 210 has a through hole, and the inner wall of the through hole is threaded. The spiral telescopic rod 211 passes through the through hole and is connected to the guide wheel 212.

[0040] In other words, during the lowering of the steel cofferdam, the guide device 2 on the steel casing is used for guidance. The guide device 2 is made of I40b I-beams and 12mm steel plates, with a 50mm rubber pad installed at its front end to increase the contact area with the steel cofferdam and ensure the wall panels are not damaged. To prevent excessive casing displacement due to pile foundation construction from hindering the lowering of the cofferdam, the displacement and inclination of the steel casing where the guide device 2 is located are measured before installation. Based on the distance, the guide device 2 is appropriately adjusted to ensure the smooth lowering of the cofferdam.

[0041] As a preferred option, the inclination angle of the inner support 6 is 45°.

[0042] As a preferred option, the cross-section of the steel concealed column is rectangular.

[0043] As a preferred option, several high-pressure water guns 31 are provided on the two sides of the steel concealed column away from the inner wall plate 11 and the outer wall plate 10 to discharge water flowing into the compartment 13. During use, after the double-walled steel cofferdam is placed on the bed, there will be difficulties in suctioning mud and sinking at the four corners of the cofferdam. In order to ensure that the cofferdam sinks straight down, high-pressure water jet pipes are set at the four corners of the cofferdam to assist in suctioning mud and sinking the cofferdam.

[0044] In other words, once the bottom sealing concrete reaches its design strength, water is pumped out of the cofferdam, and the foundation pit within the cofferdam is promptly treated. Pumping is carried out using submersible pumps evenly distributed along the cofferdam walls. During pumping, it is crucial to monitor the cofferdam's deformation to ensure safe pumping. If the water level drops slowly and deviates significantly from theoretical data, it indicates substantial seepage. Divers are then dispatched to locate the leak and take measures to plug it. If no leak is found, pumping continues. Finally, when approximately 1 meter of water remains, high-pressure water jets are used to thoroughly clean the cofferdam walls, casing walls, and the sediment from the bottom sealing concrete until all water is pumped out of the cofferdam.

[0045] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A double-walled steel cofferdam, comprising a double-walled steel cofferdam body (1) composed of an inner wall panel (11) and an outer wall panel (10) and a plurality of guiding devices (2) disposed on the inner side of the inner wall panel (11), wherein a plurality of vertical partitions (12) are provided between the outer wall panel (10) and the inner wall panel (11), and the partitions (12) divide the double-walled steel cofferdam body (1) into a plurality of compartments (13), characterized in that, It also includes steel hidden columns set around the cofferdam, bottom compartment (7) set at the bottom of the middle of the cofferdam, and several sets of bracing (5) set in the middle of the cofferdam. The steel hidden columns connect adjacent inner wall panels (11) and outer wall panels (10). The bottom compartment (7) and the bracing (5) connect symmetrically arranged inner wall panels (11). Several sets of ring beams (4) are arranged around the inner wall panels (11). The ring beams (4) are provided with inner supports (6). The inner supports (6) are fixed at both ends to the ring beams (4) or one end is fixed to the ring beams (4) and the other end is fixed to the bracing (5) to fix the inner wall panels (11).

2. The double-walled steel cofferdam according to claim 1, characterized in that, The guiding device (2) consists of a guiding base (20) and a guiding mechanism (21) disposed on the guiding base (20); the guiding base (20) is fixed to the surface of the inner wall plate (11) by a cofferdam inner wall stiffening plate (14).

3. The double-walled steel cofferdam according to claim 2, characterized in that, The guide mechanism (21) includes a thrust box (210), a spiral telescopic rod (211) and a guide wheel (212). The thrust box (210) has a through hole, and the inner wall of the through hole is threaded. The spiral telescopic rod (211) passes through the through hole and is connected to the guide wheel (212).

4. The double-walled steel cofferdam according to claim 1, characterized in that, The inclination angle of the inner support (6) is 45°.

5. The double-walled steel cofferdam according to claim 1, characterized in that, The cross-section of the steel column is rectangular.

6. The double-walled steel cofferdam according to claim 5, characterized in that, Several high-pressure water guns (31) are provided on the two sides of the steel column away from the inner wall panel (11) and the outer wall panel (10).

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