A rapid bottom sealing construction method for steel box cofferdam in strong wave sea areas

Abstract

The present invention is a method for rapidly sealing the bottom of a steel box cofferdam in strong-wave sea areas. The specific steps are as follows: after the steel casing of the pile foundation is installed, the construction drawings of the steel box cofferdam are measured and adjusted; the steel box cofferdam is assembled on the steel brackets of the steel casing, and after the cofferdam bottom plate is assembled, it is measured again. Based on the measured data, the bucket-shaped constriction structure corresponding to each steel casing is processed; after the steel box cofferdam is assembled, the entire cofferdam is lifted, and the bucket-shaped constriction structure is installed at the bottom of the cofferdam bottom keel; the steel brackets are cut off, and the steel box cofferdam is lowered as a whole to a height where the bucket-shaped constriction structure is close to the height affected by the waves. The bucket-shaped constriction structure is filled with sandbags and further secured with annular plates and stiffening ribs; the connecting holes of the steel box cofferdam are opened and the cofferdam is continued to be lowered to the designed position; and the bottom sealing concrete is poured to complete the bottom sealing operation. The present invention innovatively solves the problem that the bottom sealing operation of steel box cofferdams in strong-wave areas can only be carried out during low tide or slack tide, thereby greatly improving the construction speed.

Description

Technical Field

[0001] The invention relates to the technical field of foundation cofferdam construction, and in particular to a rapid bottom sealing construction method for a steel hanging box cofferdam in a strong wave sea area. Background Art

[0002] Sealing the bottom of a cofferdam in areas with strong waves is difficult. Waves impacting the cofferdam floor cause significant vibration, and the poured bottom concrete is easily eroded by waves, leading to bottom sealing failure. Therefore, steel box cofferdams in areas with strong waves are often used for plugging and bottom sealing during low tide. Even then, strong waves can overturn the plugging materials and bottom concrete. For long-distance bridges in areas with strong waves, construction deadlines are tight. Waiting until low tide to lower the steel boxes and seal the bottom can delay construction and cause significant losses.

[0003] Therefore, how to safely and efficiently seal the bottom of the steel box cofferdam at high tide is crucial for the construction of long-line bridge cofferdams in strong wave areas. Summary of the Invention

[0004] The present invention aims to solve the deficiencies of the prior art and provides a method for quickly sealing the bottom of a steel box cofferdam in strong wave sea areas.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0006] A method for rapid bottom sealing of a steel box cofferdam in a strong wave sea area, comprising the following specific steps:

[0007] S1. After the steel casing of the pile foundation is installed, the plane position and inclination of the steel casing are measured. Based on the measurement results, the construction drawings of the steel hanging box cofferdam are readjusted to ensure that the minimum distance between the outer wall of each steel casing and the inner edge of the surrounding cofferdam bottom keel is controlled at 20-25 cm;

[0008] S2. Assemble the steel box cofferdam on the steel bracket of the steel casing. After the cofferdam bottom plate is assembled, measure the distance between each steel casing and the inner edge of the surrounding cofferdam bottom keel again. According to the measured data, process the bucket-shaped necking structure corresponding to each steel casing;

[0009] The barrel-shaped necking structure includes a necking bottom ring plate, a necking side wall ring plate, and a necking top plate; the distance between the inner wall of the necking bottom ring plate and the outer wall of the steel casing is 5-8 cm; the necking side wall ring plate is vertical, and the bottom of the necking side wall ring plate is fixed to the necking bottom ring plate, the top of the necking side wall ring plate is welded to the bottom of the cofferdam bottom keel, and the inner wall of the necking side wall ring plate and the inner edge of the cofferdam bottom keel are arranged in an inscribed circle state, and the gap between the top of the necking side wall ring plate and the cofferdam bottom keel is filled with the necking top plate;

[0010] S3. After the steel box cofferdam is assembled, it is hoisted as a whole, and a bucket-shaped shrinkage structure is installed at the bottom of the cofferdam bottom keel of the steel box cofferdam;

[0011] S4. Cut off the steel brackets on the outer wall of the steel casing, lower the steel box cofferdam as a whole to the height of the bucket-shaped necking structure close to the maximum wave height, fill the bucket-shaped necking structure with several sandbags, and further secure the sandbags with annular plates and several stiffening ribs;

[0012] S5. Open the connecting hole of the steel box cofferdam and continue to lower the steel box cofferdam below the sea surface until it reaches the designed position;

[0013] S6. Pour the bottom seal concrete to complete the bottom seal operation;

[0014] The bottom concrete of the steel box cofferdam is poured in compartments. The area of ​​a single compartment shall not exceed six steel casings, and an experimental compartment covering only a single steel casing shall be set up. When the pouring effect of the bottom concrete in the experimental compartment is good, the bottom concrete of the remaining compartments shall be poured simultaneously.

[0015] In step S2, a plurality of shrinkage stiffening plates are evenly distributed on the circumference of the side of the shrinkage side wall ring plate facing away from the steel casing, and the shrinkage stiffening plates are connected to the shrinkage bottom ring plate, the shrinkage side wall ring plate, and the shrinkage top plate.

[0016] In step S2, the elevation of the steel corbels is ensured not to be submerged by the high tide level.

[0017] In step S4, the sandbags are made of polypropylene or polyester fiber woven bags with a diameter of 15-20 cm. The sandbags are densely filled in the barrel-shaped necking structure.

[0018] In step S4, the outer side of the annular plate is fixedly connected to the inner side of the necked top plate, and the distance between the inner side of the annular plate and the outer wall of the steel casing is 2-3 cm. The annular plate is manufactured and installed in blocks on site and finally forms a ring shape.

[0019] In step S4, the stiffening ribs are uniformly welded around the circumference between the top of the annular plate and the top of the necked top plate.

[0020] In step S5, during the lowering of the steel box cofferdam, attention is paid to the impact of the sand bags at the bucket-shaped necking structure. If damage or displacement occurs, the lowering is stopped, the position of the sand bags is readjusted, and the number of stiffening ribs is further increased. The sand bags are reinforced and compacted, and the lowering is continued until the design elevation position.

[0021] In step S6, check whether there are sand bags in the steel box cofferdam that have been eroded and displaced. If not, weld tension and compression rods. The bottom of the tension and compression rods is welded to the bottom keel of the cofferdam and the top is welded obliquely to the outer wall of the steel casing. After the tension and compression rods are successfully connected to the steel casing, remove the suspension rods on the top of the steel casing. The steel box cofferdam is transformed from a multi-point suspended state to a welded support state of multiple tension and compression rods and steel casing, completing the system conversion.

[0022] In step S6, the bottom seal concrete is quick-setting concrete.

[0023] The beneficial effects of the present invention are as follows: the present invention innovatively solves the difficult problem that the bottom sealing operation of the steel box cofferdam in strong wave areas can only be carried out during low tide and slack tide. For projects with a large number of offshore platforms and tight construction schedules, the construction speed can be greatly improved; while reducing a large amount of waiting time for high-altitude operations, the construction safety is also improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of step S3 in a specific embodiment of the present invention;

[0025] Figure 2 This is a detailed diagram of the bucket-shaped necking structure of the present invention;

[0026] Figure 3 for Figure 2 Middle AA section;

[0027] Figure 4 for Figure 2 Middle BB cross section;

[0028] Figure 5 It is a three-dimensional diagram of the bucket-shaped necking structure of the present invention;

[0029] Figure 6 This is a schematic diagram of step S4 in a specific embodiment of the present invention;

[0030] Figure 7 A three-dimensional diagram of the annular plate and the stiffening rib plate of the present invention;

[0031] Figure 8 This is a diagram of the back cover compartments in step S6 in a specific embodiment of the present invention;

[0032] In the figure: 1- steel casing; 2- cofferdam bottom keel; 3- steel corbel; 4- cofferdam bottom plate; 5- bucket-shaped necking structure; 6- sandbag; 7- annular plate; 8- tension and compression rods; 9- stiffening ribs; 10- experimental chamber;

[0033] 51-shrinking bottom ring plate; 52-shrinking side wall ring plate; 53-shrinking top plate; 54-shrinking stiffening plate;

[0034] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings. DETAILED DESCRIPTION

[0035] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention. The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are all in a very simplified form and are not in exact proportions, and are only used to facilitate and clearly illustrate the purpose of the embodiments of the present invention.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] The present invention will be further described below with reference to the accompanying drawings and examples:

[0038] A method for rapid bottom sealing of a steel box cofferdam in a strong wave sea area, comprising the following specific steps:

[0039] S1. After the steel casing 1 of the pile foundation is installed, the plane position and inclination of the steel casing 1 are measured. According to the measurement results, the construction drawing of the steel hanging box cofferdam is readjusted so that the minimum distance between the outer wall of each steel casing 1 and the inner edge of the surrounding cofferdam bottom keel 2 is controlled at 20-25 cm.

[0040] S2. Assemble the steel box cofferdam on the steel bracket 3 of the steel casing 1. After the cofferdam bottom plate 4 is assembled, measure the distance between each steel casing 1 and the inner edge of the surrounding cofferdam bottom keel 2 again. According to the measured data, process the bucket-shaped necking structure 5 corresponding to each steel casing 1.

[0041] The bucket-shaped necking structure 5 should completely cover the cofferdam bottom keel 2 and leave a gap between it and the corresponding steel casing 1. The specific structure is as follows:

[0042] Bucket-shaped necking structure 5 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 As shown, it includes a necked bottom ring plate 51 , a necked side wall ring plate 52 and a necked top plate 53 .

[0043] The distance between the inner wall of the necked bottom ring plate 51 and the outer wall of the steel casing 1 is 5-8 cm, for example, 7 cm, which is convenient for later sealing.

[0044] The necking side wall ring plate 52 is vertical, which is convenient for cutting and processing and on-site installation; the bottom of the necking side wall ring plate 52 is fixed on the necking bottom ring plate 51, and the top of the necking side wall ring plate 52 is welded to the bottom of the cofferdam bottom keel 2, and the inner wall of the necking side wall ring plate 52 and the inner edge of the cofferdam bottom keel 2 are arranged in an inscribed circle state, which is convenient for the smooth pouring of sealing concrete.

[0045] The gap between the top of the necked side wall ring plate 52 and the cofferdam bottom keel 2 is filled and welded with a necked top plate 53 , and the edge of the necked top plate 53 is fixedly connected to the cofferdam bottom keel 2 by a weld.

[0046] Several shrinking stiffeners 54 are evenly distributed around the circumference of the sidewall ring plate 52 facing away from the steel casing 1. The shrinking stiffeners 54 connect the shrinking bottom ring plate 51, the shrinking sidewall ring plate 52, and the shrinking top plate 53. The shrinking stiffeners 54 strengthen the connection between the shrinking bottom ring plate 51, the shrinking sidewall ring plate 52, and the shrinking top plate 53 and increase the overall rigidity of the bucket-shaped shrinking structure 5.

[0047] The steel corbel elevation 3 ensures that it will not be submerged by high tide and will not be disturbed by waves during high tide.

[0048] S3. After the steel box cofferdam is assembled, the PLC control system is used to synchronously lift the steel box cofferdam on top of multiple steel casings 1. Figure 1 As shown, a bucket-shaped necking structure 5 is installed at the bottom of the cofferdam bottom keel 2 of the steel hanging box cofferdam.

[0049] S4, cut off the steel bracket 3 on the outer wall of the steel casing 1, lower the steel box cofferdam as a whole to the bucket-shaped necking structure 5 close to the height affected by the maximum wave height, use several sand bags 6 to fill the bucket-shaped necking structure 5, and use the annular plate 7 and several stiffening ribs 9 to further fix the sand bags 6, as shown in the figure. Figure 6 、 Figure 7 As shown, this is to prevent the sandbags 6 from being washed away and displaced by waves after the steel box cofferdam is lowered into place.

[0050] The sandbags 6 are made of polypropylene or polyester fiber woven bags to prevent the sandbags 6 from being eroded and damaged by waves, thereby causing sealing failure; the diameter of the sandbags 6 is 15-20 cm; the sandbags 6 are densely filled in the bucket-shaped necking structure 5.

[0051] For the convenience of installation, the annular plate 7 is processed on site, manufactured and installed in blocks, and finally forms a ring shape. Specifically, the annular plate 7 corresponding to a single steel casing 1 is manufactured in four blocks on site, and the blocks are installed to form a ring shape.

[0052] The outer side of the annular plate 7 is fixedly connected to the inner side of the necked top plate 53, and the inner side of the annular plate 7 retains a certain distance from the outer wall of the steel casing 1; the reserved distance between the inner side of the annular plate 7 and the outer wall of the steel casing 1 should be determined according to the residual welding material on the outer wall of the steel casing 1. Preferably, the inner side of the annular plate 7 is 2-3 cm away from the outer wall of the steel casing 1, so that the reserved distance can smoothly pass through the welding residue on the outer wall of the steel casing 1 during the lowering of the steel box cofferdam, thereby ensuring the smooth lowering of the steel box cofferdam.

[0053] The stiffening ribs 9 are evenly welded around the circumference between the top of the annular plate 7 and the top of the necked top plate 53. The stiffening ribs 9 serve to increase the rigidity of the annular plate 7 and thereby resist the impact of waves, thereby preventing the sandbags 6 from being destroyed or displaced by the surge of waves.

[0054] S5. Open the connecting hole of the steel box cofferdam and continue to lower the steel box cofferdam below the sea surface until it reaches the designed position;

[0055] During the lowering of the steel box cofferdam, always pay attention to the impact of the sand bags 6 at the bucket-shaped necking structure 5. If they are destroyed or shifted, stop lowering, readjust the position of the sand bags 6, and further increase the number of stiffening ribs 9 to reinforce and compact the sand bags 6. Continue lowering until they reach the designed elevation.

[0056] The impact of the sandbags 6 at the bucket-shaped necking structure 5 is monitored by visual observation, specifically:

[0057] If the sandbags 6 are eroded and broken by the waves, the sand filled inside will overflow. Under the upward impact of the waves, sand can be observed surging in the water inside the steel box cofferdam. In addition, the sandbags 6 may also be broken into rags by the waves, or even washed into the steel box cofferdam from the bucket-shaped necking structure 5. In both cases, it is possible to observe with the naked eye whether the sandbags 6 are eroded and damaged.

[0058] Of course, it is allowed that the sand bags 6 have only slight displacement in the bucket-shaped necking structure 5, and the sand bags 6 are flushed out of small holes and sand leaks slightly. As long as multiple sand bags 6 can fill the space of the bucket-shaped necking structure 5 and there is no large-scale loss of sand in the bucket-shaped necking structure 5 causing voids, it can alleviate the impact of waves and help the smooth casting of the bottom seal.

[0059] S6. Pour the bottom seal concrete to complete the bottom seal operation;

[0060] Check whether there are sand bags 6 in the steel box cofferdam that have been eroded and displaced. If not, weld the tension and compression rods 8. The bottom of the tension and compression rods 8 is welded to the bottom keel 2 of the cofferdam and the top is welded obliquely to the outer wall of the steel casing 1. After the tension and compression rods 8 are successfully connected to the steel casing 1, remove the suspension rods on the top of the steel casing 1. The steel box cofferdam is transformed from a multi-point suspended state to a welded support state of multiple tension and compression rods 8 and the steel casing 1, completing the system conversion.

[0061] The bottom concrete of the steel box cofferdam is poured in each compartment. The bottom concrete is quick-setting concrete. The area of ​​a single compartment does not exceed six steel casings 1. A test compartment 10 covering only a single steel casing 1 is set. Figure 8 As shown, when the pouring effect of the bottom concrete of the experimental chamber 10 is good, the bottom concrete of the remaining chambers will be poured simultaneously.

[0062] The working principle of the present invention is:

[0063] First, a bucket-shaped necking structure 5 is used to reduce the distance between the steel casing 1 and the cofferdam bottom keel 2, thereby reducing the difficulty of necking processing, on-site installation, and bottom sealing;

[0064] Secondly, at a height not affected by waves, the gap between the bucket-shaped constricted structure 5 and the steel casing 1 is filled with a number of sandbags 6, and an annular plate 7 is covered on top of the sandbags 6. The annular plate 7 further reduces the gap between the steel casing 1 and the steel hanging box cofferdam; the multi-layer sandbags 6 directly bear the impact of the waves, playing a role in buffering and absorbing energy;

[0065] Finally, after the steel box cofferdam is lowered into place, the space between the bucket-shaped necking structure 5, the annular plate 7 and the steel casing 1 is filled with dense sandbags 6. Only a small amount of concrete enters the space when pouring the bottom concrete. Under the support and wave-breaking effect of the sandbags 6, the bottom concrete is not easily dispersed, which can provide a certain amount of time for the concrete to solidify and harden, thereby greatly improving the probability of successful bottom sealing.

[0066] At the same time, when calculating the anti-floating stability of the steel box cofferdam, the horizontal bond force between the small amount of concrete poured in the indentation and the steel casing 1 is ignored, and more use is made of the anti-floating force provided by the tension and compression rods 8 and the shear connection keys.

[0067] The present invention innovatively solves the problem that the bottom sealing operation of the steel box cofferdam in strong wave areas can only be carried out during low tide and slack tide. It can greatly improve the construction speed for projects with a large number of offshore platforms and tight construction schedules; while reducing a large amount of waiting time for high-altitude operations, it also improves construction safety.

[0068] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or they are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A method for rapid bottom sealing of a steel box cofferdam in a strong wave sea area, characterized in that: The specific steps are: S1. After the steel casing (1) of the pile foundation is driven, the plane position and inclination of the steel casing (1) are measured. Based on the measurement results, the construction drawing of the steel hanging box cofferdam is readjusted so that the minimum distance between the outer wall of each steel casing (1) and the inner side of the surrounding cofferdam bottom keel (2) is controlled at 20-25 cm; S2. Assemble the steel box cofferdam on the steel bracket (3) of the steel casing (1). After the cofferdam bottom plate (4) is assembled, measure the distance between each steel casing (1) and the inner edge of the surrounding cofferdam bottom keel (2) again. According to the measured data, process the bucket-shaped shrinkage structure (5) corresponding to each steel casing (1); The barrel-shaped necking structure (5) includes a necking bottom ring plate (51), a necking side wall ring plate (52) and a necking top plate (53); the distance between the inner wall of the necking bottom ring plate (51) and the outer wall of the steel casing (1) is 5-8 cm; the necking side wall ring plate (52) is vertical and the bottom of the necking side wall ring plate (52) is fixed on the necking bottom ring plate (51), the top of the necking side wall ring plate (52) is welded to the bottom of the cofferdam bottom keel (2) and the necking side wall ring plate The inner wall (52) and the inner edge of the cofferdam bottom keel (2) are arranged in an inscribed circle state, the gap between the top of the shrinking side wall ring plate (52) and the cofferdam bottom keel (2) is filled and welded with a shrinking top plate (53), and a plurality of shrinking stiffening plates (54) are evenly distributed on the circumference of the side of the shrinking side wall ring plate (52) facing away from the steel casing (1), and the shrinking stiffening plates (54) are connected to the shrinking bottom ring plate (51), the shrinking side wall ring plate (52), and the shrinking top plate (53); S3. After the steel box cofferdam is assembled, it is hoisted as a whole, and a bucket-shaped shrinkage structure (5) is installed at the bottom of the cofferdam bottom keel (2) of the steel box cofferdam; S4, cutting off the steel bracket (3) on the outer wall of the steel casing (1), lowering the steel box cofferdam as a whole to the height close to the maximum wave height of the bucket-shaped constriction structure (5), using a plurality of sand bags (6) to fill the bucket-shaped constriction structure (5), and further fixing the sand bags (6) with an annular plate (7) and a plurality of stiffening ribs (9), the outer side of the annular plate (7) is fixedly connected to the inner side of the constriction top plate (53), and the distance between the inner side of the annular plate (7) and the outer wall of the steel casing (1) is 2-3 cm. The annular plate (7) is manufactured and installed in blocks on site, and finally forms a ring shape; S5. Open the connecting hole of the steel box cofferdam and continue to lower the steel box cofferdam below the sea surface until it reaches the designed position; S6. Pour the bottom seal concrete to complete the bottom seal operation; The bottom concrete of the steel box cofferdam is poured in each compartment, and the area of ​​a single compartment does not exceed six steel casings (1). A test compartment (10) covering only a single steel casing (1) is set up. When the pouring effect of the bottom concrete of the test compartment (10) is good, the bottom concrete of the remaining compartments is poured synchronously.

2. The method for rapid bottom sealing of a steel box cofferdam in a strong wave sea area according to claim 1 is characterized in that: In step S2, the elevation of the steel corbel (3) is ensured not to be submerged by the high tide level.

3. The method for rapid bottom sealing of a steel box cofferdam in a strong wave sea area according to claim 2 is characterized in that: In step S4, the sandbag (6) is a polypropylene or polyester fiber woven bag, the diameter of the sandbag (6) is 15-20 cm, and the sandbag (6) is densely filled in the bucket-shaped necking structure (5).

4. The method for rapid bottom sealing of a steel box cofferdam in a strong wave sea area according to claim 3 is characterized in that: In step S4, the stiffening rib plate (9) is uniformly welded around the circumference between the top of the annular plate (7) and the top of the necked top plate (53).

5. The method for rapid bottom sealing of a steel box cofferdam in a strong wave sea area according to claim 4 is characterized in that: In step S5, during the lowering of the steel box cofferdam, attention is paid to the impact of the sandbags (6) at the bucket-shaped necking structure (5). If the sandbags (6) are damaged or displaced, the lowering is stopped, the positions of the sandbags (6) are readjusted, and the number of stiffening ribs (9) is further increased to reinforce and compact the sandbags (6). The sandbags (6) are then continued to be lowered until they reach the designed elevation.

6. The method for rapid bottom sealing of a steel box cofferdam in a strong wave sea area according to claim 5 is characterized in that: In step S6, it is checked whether there are sand bags (6) in the steel box cofferdam that are eroded and displaced. If not, the tension and compression rods (8) are welded. The bottom of the tension and compression rods (8) is welded to the bottom keel (2) of the cofferdam and the top is welded obliquely to the outer wall of the steel casing (1). After the tension and compression rods (8) are successfully connected to the steel casing (1), the suspension rods on the top of the steel casing (1) are removed. The steel box cofferdam is transformed from a state of being suspended at multiple points to being supported by welding multiple tension and compression rods (8) and the steel casing (1), completing the system conversion.

7. The method for rapid bottom sealing of a steel box cofferdam in a strong wave sea area according to claim 6 is characterized in that: In step S6, the bottom seal concrete is quick-setting concrete.

Images