A method for underwater bottom sealing construction of super-large and super-deep caisson

Abstract

The invention discloses an underwater bottom sealing construction method for a super-large and super-deep caisson. During the first pouring of concrete, the bottom of the caisson is not completely formed, the water body in the caisson is connected to the water body of the Yangtze River through the soil body, the water level in the caisson is kept stable, and the elevation of the steel conduit remains unchanged. In the concrete pouring stage after the first pouring is completed, the caisson wall and the bottom concrete form a complete whole that can maintain the volume of the water body in the caisson unchanged. The buoyancy of the steel pontoon during the rising water level is used to automatically lift the steel conduit erected on the steel pontoon water construction platform, without the need for manual cooperation with a car crane to lift the conduit, and without the need for manual removal of the conduit. The number of steel pontoon water construction platforms and the funnel volume of the steel conduit are consistent with the total volume of concrete, and the total volume of the funnel is equal to the volume of concrete in the first pouring. During the placement process, the steel pontoon water construction platform is evenly placed on the water surface of the caisson, and the buried depth of the conduit in the concrete is easy to control, which is particularly suitable for the field of undrained caisson construction.

Description

Technical Field

[0001] The invention belongs to the technical field of caisson construction, and in particular relates to an underwater bottom sealing construction method for an ultra-large and ultra-deep caisson. Background Art

[0002] At present, in the construction of caisson bottom sealing, the traditional construction method is to use a large steel truss to erect on the top of the caisson, and insert the steel conduit vertically into the bottom of the well for bottom sealing. During the concrete pouring process, lifting machinery is required to manually lift the conduit. The insertion depth of the conduit in the concrete during the pouring process requires special attention from on-site construction operators, and the control of this data directly affects the construction quality. When the steel truss has reached the maximum height but the caisson bottom sealing has not yet been completed, in order to further lift the steel conduit and avoid various problems caused by stopping the lifting of the steel conduit, the staff needs to suspend the pouring operation, shorten the length of the steel conduit by disassembly in a short time, and then lower the steel truss to the height at which the steel truss was when the lifting began, so as to continue to lift the conduit. The conduit lifting process is complicated and has high requirements for operation, which directly affects the quality of concrete pouring. Summary of the invention

[0003] In order to overcome the technical defects in the prior art that manual cooperation with a car crane is required to lift the guide tube, the operation requirements are high, water easily enters the pipeline due to the guide tube being pulled out of the concrete, and the concrete pouring is interrupted for too long during the removal of the guide tube, causing pipe blockage and other problems, the present invention provides an underwater bottom sealing construction method for an ultra-large and ultra-deep caisson, which maintains the volume of the water body in the well unchanged by forming a complete whole with the caisson wall and the bottom of the well, and automatically lifts the steel guide tube by the buoyancy of the steel pontoon during the rising water level. The buried depth of the guide tube is easy to control, avoiding manual cooperation with a car crane to lift the steel guide tube and manual removal of the steel guide tube, thereby solving the above-mentioned technical problems.

[0004] A method for underwater bottom sealing of an ultra-large and ultra-deep caisson, the method comprising the following construction steps:

[0005] S1: The steel pontoon water construction platform is made by on-site welding or prefabrication by the manufacturer. After the on-site caisson bottom sealing construction preparation work is completed, the steel pontoon water construction platform is hoisted into the caisson in sequence by lifting equipment and moved to the designated position. The steel pontoon water construction platform is fixed by steel wire rope and embedded parts. The funnel bracket is welded on the steel pontoon water construction platform, and the steel conduit is placed. The bottom of the steel conduit is straightened to the inside of the caisson progress soil surface, with a distance of 300mm-400mm, and the construction equipment is arranged;

[0006] S2: Before pouring concrete, the steel conduit is blocked with a ball plug. The ball plug is tied with a steel rope or thick iron wire and fixed to the funnel neck of the steel conduit. At the same time, the height of the ball plug is controlled so that the center elevation of the ball plug is higher than the water surface elevation in the well.

[0007] S3: During pouring, cement mortar is injected into the steel conduit feeding funnel to wet the ball plug, so that the ball plug can slide smoothly during the concrete pouring process. The steel conduit feeding funnel is filled with concrete, and the steel wire rope or thick iron wire is slowly lowered to reduce the elevation of the ball plug. During concrete pouring, each steel pontoon water construction platform is constructed at the same time. The rope or thick iron wire is disconnected and concrete is continuously injected into the steel conduit feeding funnel. Under the action of gravity, the ball plug pushes the air and water in the steel conduit to be discharged from the bottom of the steel conduit. Then the gushing concrete gathers at the bottom of the steel conduit at the bottom of the well to form a conical concrete pile, and quickly wraps the bottom of the steel conduit;

[0008] S4: Before the concrete pouring is completed, concrete with high fluidity is used for pouring. At the end of the concrete pouring, the concrete surface elevation needs to be 100mm-200mm higher than the design elevation. After the concrete pouring is completed, the steel pipe is pulled out of the concrete, rinsed clean, and the caisson bottom sealing construction is completed.

[0009] The above-mentioned method for underwater bottom sealing construction of an extra-large and extra-deep caisson, the steel pontoon water construction platform in step S3 is formed by welding together two steel pontoons, two arc-shaped I-beams and a steel plate, the arc-shaped I-beam and the steel plate are welded between the two steel pontoons to form the two steel pontoons as a whole, a funnel bracket is welded on the upper part of the steel plate, the central hole of the funnel bracket is coaxial with the central circular hole of the steel plate, the feeding funnel of the steel conduit is placed on the funnel bracket, the lower end of the steel conduit passes through the central circular hole of the funnel bracket and the steel plate, the bottom of the steel conduit is straightened to the vicinity of the soil surface of the caisson progress, and the distance is 300mm-400mm.

[0010] The above-mentioned method for underwater bottom sealing construction of an extra-large and extra-deep caisson is characterized in that circular rings are welded at the four corners of the steel pontoon water construction platform, one end of the steel wire rope is connected and fixed to the circular ring, and the other end is tied to the embedded parts in the caisson wall, so as to keep the horizontal position of the steel pontoon water construction platform relatively stable during the pouring of the bottom sealing concrete, and prevent the steel conduit from moving around during the concrete pouring process and causing displacement in the horizontal direction.

[0011] In the above-mentioned method for underwater bottom sealing construction of an extra-large and extra-deep caisson, the number of the steel pontoon water construction platforms and the funnel volume of the steel conduit are consistent with the total volume of concrete, so that the total volume with the funnel is equal to the volume of concrete in the first pouring, and the steel pontoon water construction platforms are evenly placed on the water surface in the caisson during the placement process.

[0012] In general, compared with the prior art, the above technical scheme conceived by the present invention can achieve the following beneficial effects: the present invention provides an underwater bottom sealing construction method for an ultra-large and ultra-deep caisson. During the first pouring of concrete, the bottom of the caisson is not completely formed, and the water body in the caisson is connected to the water body of the Yangtze River through the soil. The water level in the caisson remains stable, and the elevation of the steel conduit remains unchanged. In the concrete pouring stage after the first pouring is completed, a complete whole that can maintain the volume of the water body in the caisson is formed by the caisson wall and the bottom concrete. The buoyancy of the steel pontoon during the rising water level is utilized to automatically lift the steel conduit erected on the steel pontoon water construction platform. There is no need for manual cooperation with a car crane to lift the conduit, and there is no need for manual disassembly of the conduit. The buried depth of the conduit in the concrete is easy to control, which can significantly reduce the cost of engineering equipment and improve the quality of the caisson bottom sealing. It is particularly suitable for the field of undrained caisson construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein:

[0014] Figure 1 It is a schematic diagram of the planar layout of the construction device of the underwater bottom sealing construction method of a super-large and super-deep caisson of the present invention;

[0015] Figure 2 It is a top view of the steel pontoon water construction platform of the present invention;

[0016] Figure 3 It is a cross-sectional view of the steel pontoon water construction platform of the present invention;

[0017] Figure 4 This is a cross-sectional view of the caisson when the first pouring of concrete is completed in the present invention;

[0018] Figure 5 This is a cross-sectional view of the caisson in the concrete pouring stage after the first pouring of the present invention is completed;

[0019] In the figure: 1- steel pontoon water construction platform, 2- steel pontoon, 3- arc I-beam, 4- steel plate, 5- steel wire rope, 6- embedded parts, 7- well wall, 8- funnel bracket, 9- steel conduit. DETAILED DESCRIPTION

[0020] like Figure 1 As shown, it is a schematic diagram of the planar layout of the construction device adopted in the underwater bottom sealing construction method of an ultra-large and ultra-deep caisson of the present invention. Circular rings are welded at the four corners of the steel pontoon water construction platform 1, one end of the steel wire rope 5 is connected and fixed to the circular ring, and the other end is tied to the embedded part 6 in the wall of the caisson, so as to keep the horizontal position of the steel pontoon water construction platform 1 relatively stable during the pouring of the bottom sealing concrete, and prevent the steel conduit 9 from moving around during the concrete pouring process and causing displacement in the horizontal direction.

[0021] like Figure 2and Figure 3 As shown, it is a top view and a cross-sectional view of a single steel pontoon water construction platform 1 of the present invention. The steel pontoon water construction platform 1 is welded by two steel pontoons 2, two arc-shaped I-beams 3 and a steel plate 4. The arc-shaped I-beam 3 and the steel plate 4 are welded between the two steel pontoons 2 to form the two steel pontoons 2 as a whole. A funnel bracket 8 is welded on the upper part of the steel plate 4. The central hole of the funnel bracket 8 is coaxial with the central circular hole of the steel plate 4. The feeding funnel of the steel conduit 9 is placed on the funnel bracket 8. The lower end of the steel conduit 9 passes through the central circular holes of the funnel bracket 8 and the steel plate 4. The bottom of the steel conduit 9 is straightened near the soil surface of the caisson progress, and the distance is 300mm-400mm.

[0022] When the present invention is used to carry out the bottom sealing construction of an ultra-large and ultra-deep caisson, the following construction steps are included:

[0023] Step 1: Make the steel pontoon water construction platform by on-site welding or prefabrication. After the on-site caisson bottom sealing construction preparation work is completed, the steel pontoon water construction platform 1 is hoisted into the caisson in sequence by lifting equipment and moved to the designated position. The steel pontoon water construction platform 1 is fixed by steel wire rope 5 and embedded parts 6. The funnel bracket 8 is welded on the steel pontoon water construction platform 1, and the steel conduit 9 is placed. The bottom of the steel conduit 9 is straightened to the inside of the caisson progress soil surface, and the distance is 300mm-400mm. The construction equipment is arranged;

[0024] Step 2: Before pouring concrete, the steel conduit 9 is blocked with a ball plug, which is tied with a steel rope or thick iron wire and fixed to the funnel neck of the steel conduit 9. At the same time, the elevation of the ball plug is controlled so that the center elevation of the ball plug is higher than the water surface elevation in the well;

[0025] Step 3: During pouring, cement mortar is injected into the feeding funnel of the steel conduit 9 to wet the ball plug, so that the ball plug can slide smoothly during the concrete pouring process. The feeding funnel of the steel conduit 9 is filled with concrete, and the steel wire rope or thick iron wire is slowly lowered to reduce the elevation of the ball plug. During concrete pouring, each steel pontoon water construction platform 1 is constructed at the same time. The rope or thick iron wire is disconnected and concrete is continuously injected into the feeding funnel of the steel conduit 9. Under the action of gravity, the ball plug pushes the air and water in the steel conduit 9 to be discharged from the bottom of the steel conduit 9. Then the gushing concrete gathers at the bottom of the steel conduit 9 at the bottom of the well to form a conical concrete pile, and quickly wraps the bottom of the steel conduit 9;

[0026] Step 4: Before the concrete pouring is completed, concrete with greater fluidity is used for pouring. At the end of the concrete pouring, the concrete surface elevation needs to be 100mm-200mm higher than the design elevation. After the concrete pouring is completed, the steel conduit 9 is pulled out of the concrete, rinsed clean, and the caisson bottom sealing construction is completed.

[0027] The number of steel pontoon water construction platforms 1 and the funnel volume of the steel conduit 9 are consistent with the total volume of concrete, so that the total volume of the funnel is equal to the volume of concrete in the first pouring. The steel pontoon water construction platform 1 is evenly placed on the water surface in the caisson during the placement process.

[0028] During the first pouring of concrete, the bottom of the caisson has not been completely formed, the water in the caisson is connected to the water of the Yangtze River through the soil, the water level in the well remains stable, and the elevation of the steel guide tube 9 remains unchanged. When the first pouring of concrete is completed, the elevation of the concrete surface is equal to the elevation of the blade foot, the end of the steel guide tube 9 is buried in the concrete, the caisson wall and the concrete at the bottom of the well form a complete whole, and the water in the well is cut off from the outside world.

[0029] During the concrete pouring phase after the first pouring, the volume of water in the well remains unchanged. Figure 4 and Figure 5 As shown, with the increase of the volume of poured concrete in the well, the water level in the well gradually rises, and the steel pontoon water construction platform 1 rises within a certain range by utilizing the buoyancy of the water body, driving the steel conduit 9 placed thereon to rise, thereby realizing automatic lifting of the steel conduit 9. There is no need for manual cooperation with a car crane to lift the conduit, and there is no need for manual disassembly of the conduit. The buried depth of the conduit in the concrete is easy to control, which can significantly reduce the cost of engineering equipment and improve the quality of the bottom sealing of the caisson, and is particularly suitable for the field of undrained caisson construction.

[0030] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for underwater bottom sealing of an ultra-large and ultra-deep caisson, the method comprising the following construction steps: S1: The steel pontoon water construction platform (1) is manufactured by on-site welding or prefabrication by a manufacturer. After the on-site preparation work for the bottom sealing of the caisson is completed, the steel pontoon water construction platform (1) is hoisted into the caisson in sequence by a lifting device and moved to a designated position. The steel pontoon water construction platform (1) is fixed by a steel wire rope (5) and an embedded part (6). A funnel bracket (8) is welded on the steel pontoon water construction platform (1), and a steel guide tube (9) is placed. The construction equipment is arranged. S2: Before pouring concrete, the steel conduit (9) is sealed with a ball plug, which is tied with a steel wire rope or a thick iron wire and fixed to the funnel neck of the steel conduit (9). At the same time, the height of the ball plug is controlled so that the center elevation of the ball plug is higher than the water surface elevation in the well; S3: During pouring, cement mortar is injected into the feeding funnel of the steel conduit (9) to wet the ball plug so that the ball plug can slide smoothly during the concrete pouring process. The feeding funnel of the steel conduit (9) is filled with concrete, and the steel wire rope or thick iron wire is slowly lowered to reduce the height of the ball plug. During concrete pouring, each steel pontoon water construction platform (1) is constructed simultaneously. The steel wire rope or thick iron wire is disconnected while continuously injecting concrete into the feeding funnel of the steel conduit (9). Under the action of gravity, the ball plug pushes the air and water in the steel conduit (9) to be discharged from the bottom of the steel conduit (9). Subsequently, the gushing concrete gathers at the bottom of the steel conduit (9) at the bottom of the well to form a conical concrete pile, and quickly wraps the bottom of the steel conduit (9). The steel pontoon water construction platform (1) is welded together by two steel pontoons (2), two arc-shaped I-beams (3) and a steel plate (4). The arc-shaped I-beam (3) and the steel plate (4) are welded together. ) are welded between the two steel pontoons (2) so that the two steel pontoons (2) form a whole, a funnel bracket (8) is welded on the upper part of the steel plate (4), the central hole of the funnel bracket (8) is coaxial with the central circular hole of the steel plate (4), the feeding funnel of the steel conduit (9) is placed on the funnel bracket (8), the lower end of the steel conduit (9) passes through the central circular holes of the funnel bracket (8) and the steel plate (4), and the bottom of the steel conduit (9) extends into the vicinity of the soil surface in the caisson, with a distance of 300mm-400mm; circular rings are welded at the four corners of the steel pontoon water construction platform (1), one end of the steel wire rope (5) is connected and fixed to the circular ring, and the other end is tied to the embedded part (6) in the wall of the caisson, so as to keep the horizontal position of the steel pontoon water construction platform (1) relatively stable during the pouring of the bottom concrete, and prevent the steel conduit (9) from moving around during the concrete pouring process and causing displacement in the horizontal direction; S4: Before the concrete pouring is completed, concrete with high fluidity is used for pouring. At the end of the concrete pouring, the concrete surface elevation needs to be 100 mm to 200 mm higher than the design elevation. After the concrete pouring is completed, the steel conduit (9) is pulled out of the concrete and rinsed clean. The bottom sealing construction of the caisson is completed.

2. The underwater bottom sealing construction method of a super-large and super-deep caisson according to claim 1 is characterized in that: The number of the steel pontoon water construction platforms (1) and the funnel volume of the steel conduit (9) are consistent with the total volume of concrete, so that the total volume of all the funnels is equal to the volume of concrete in the first pouring. The steel pontoon water construction platforms (1) are evenly placed on the water surface in the caisson during the placement process.

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