Strengthening construction method for open caisson blade foot formwork

Abstract

The invention relates to the technical field of open caisson construction, and discloses an open caisson blade foot template reinforcing construction method which comprises the following steps: S1, construction preparation: deepening a diagonal bracing body at a chamfer on the inner side of a blade foot according to an open caisson design drawing, manufacturing according to blocks, and preparing conventional materials; the construction method comprises the following steps: firstly, positioning a side line of a cushion layer and a positioning hole of a diagonal bracing body in a construction site, and carrying out cushion layer construction after the bearing capacity and the flatness meet the requirements; S3, mounting the diagonal bracing body; S4, mounting reinforcing steel bars and a template; S5, pouring and maintaining concrete; the multiple layers of bamboo plywood are used as the formwork, the surface is smooth, the weight is light, carrying and mounting are convenient, the appearance quality can be improved, the labor intensity is reduced, meanwhile, the formwork can be matched with the shape of the open caisson through shaping machining, slurry leakage is prevented, the formworks are meshed through staggered joint splicing, cooperative stress can be achieved during pouring, the stability of a formwork system is enhanced, and deformation is reduced; and the concrete pouring quality and the construction efficiency are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of caisson construction, in particular to a caisson blade foot template reinforcement construction method. Background Art

[0002] In caisson construction, the reinforcement of the formwork at the blade foot is extremely critical. As a special underground structure, the blade foot of the caisson needs to withstand large lateral pressure and vertical loads from the soil. It is the cornerstone to ensure the stability and accuracy of the caisson structure. A stable formwork can effectively resist the huge pressure and lateral force during concrete pouring, and prevent the formwork from deforming and displacing, thereby ensuring that the blade foot of the caisson is accurate in size and regular in shape, meeting the design requirements. In the current caisson construction process, the installation of the blade foot formwork usually adopts technologies such as brick formwork masonry of the blade foot and assembly of formwork blocks.

[0003] However, in the current technology, the turnover rate of the formwork is low during the caisson construction process, and the brick formwork laying cycle and the mortar strength reaching the design requirements are long. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a caisson blade foot formwork reinforcement construction method to solve the problems of low formwork turnover utilization rate, long brick formwork laying cycle and long period for mortar strength to reach design requirements.

[0005] To achieve the above purpose, the present invention is implemented by the following technical scheme: a caisson blade foot template reinforcement construction method, comprising the following steps: S1. Construction preparation: According to the caisson design drawings, deepen the diagonal brace at the inner chamfer of the blade foot, make it in blocks and prepare conventional materials; S2. Pad construction: First, locate the pad edge line and the positioning holes of the diagonal brace at the construction site. After the bearing capacity and flatness meet the requirements, proceed with pad construction; S3. Installation of diagonal brace: locate the inner and outer edges of the caisson blade foot, and then install the diagonal brace blocks one by one according to the positioning lines, and fill the contact surface between the diagonal brace blocks and the caisson cushion layer with thick sponge double-sided tape; S4. Installation of steel bars and formwork: The formwork is made of multi-layer bamboo plywood, which is shaped according to the size and curvature of the inner and outer walls of the caisson, and the square caisson side wall formwork is assembled with staggered joints of the upper and lower layers; S5. Concrete pouring and curing: Before pouring concrete, check the centerline position of the caisson and the reserved embedded position, check the template reinforcement and joints, remove debris, and then use an inserted vibrator to assist in concrete pouring, and perform curing after pouring; S6. Removal of formwork and diagonal bracing blocks: Conduct a pressure test. When the concrete strength reaches 2.5 MPa, remove the side formwork that does not bear the weight of concrete. When the concrete reaches 75% of the design strength, remove the formwork and diagonal bracing blocks or pour the next section of concrete.

[0006] Preferably, the diagonal brace in S1 comprises an external steel plate, which is filled with a high-strength polystyrene filler and a positioning rod. The positioning rod is used to position the plain round steel bars for welding under the diagonal brace. The welding angle is consistent with the diagonal brace angle. A straight brace is used at the groove of the caisson bottom plate, which comprises an external bamboo plywood, which is filled with a high-strength polystyrene filler, and is fixed to the inner formwork with screws. The conventional materials include formwork, three-section tension bolts, plain round steel bars and steel pipes, and auxiliary materials required for construction.

[0007] Preferably, the positioning holes in S2 are reserved holes for embedded PVC pipes, and the cushion layer is constructed with a width of 50 cm on both sides of the well wall and a thickness of 25-30 cm.

[0008] Preferably, the positioning rod in the diagonal brace body of S3 is installed by fully wrapping it with double-sided sponge tape, the diagonal brace blocks 1 are filled with 1mm-2mm thick double-sided sponge tape, the thickness of the thick double-sided sponge tape between the contact surface of the diagonal brace block and the caisson cushion is 2-3mm, and the contact between the diagonal brace block and the tension bolt is made of detachable tension bolts, and the contact points are sealed with waterproof tape.

[0009] Preferably, the step of installing the steel bars and the formwork in S4 comprises: S01. Install the formwork inside the caisson and the straight support body at the groove of the bottom plate, and apply the release agent; S02, install the inclined iron at the bottom of the blade foot and the steel bar at the bottom of the blade foot; S03, the bottom inclined iron of the blade foot is welded and fixed to the bottom steel bar; S04. Continue to tie the upper reinforcement to the primary pouring height; S05. Install the outer formwork and apply the release agent, install the tension screws and protective layer pads, and the spacing specifications of the tension screws, the spacing and specifications of the primary and secondary ribs must be determined according to the design calculation; S06. Comprehensively check the template installation quality and acceptance.

[0010] Preferably, the concrete pouring in S5 is carried out according to the principle of "from low to high, symmetrical layering", the layer thickness is controlled at about 30 cm, the displacement spacing of the inserted vibrator does not exceed 1.5 times the action radius of the vibrator, and a distance of 5 to 10 cm is maintained from the side form. The depth of insertion into the lower layer of concrete is 5 to 10 cm, and the vibration duration of each vibration point is 20 to 30 seconds. The concrete pouring is completed and cured in time, and the curing adopts moisturizing curing at 15-35°C and heat preservation curing at -5-15°C.

[0011] Preferably, the concrete strength in S6 is determined by a rebound test and a test block strength test, the diagonal brace body is taken out by prying the bottom surface with a crowbar, the formwork and the straight brace body are not removed after being fixed, and the formwork, diagonal brace block and straight brace block are subsequently removed for cleaning and maintenance.

[0012] The present invention provides a method for reinforcing a caisson blade foot formwork. It has the following beneficial effects: 1. The present invention uses multi-layer bamboo plywood as a template, which has a smooth surface, light weight, is easy to carry and install, can improve the appearance quality, and reduce labor intensity. At the same time, after finalization processing, it can match the shape of the caisson to prevent leakage of slurry. The staggered splicing makes the templates bite each other, can coordinate the force during pouring, enhance the stability of the template system, reduce deformation, and ensure the quality of concrete pouring and construction efficiency.

[0013] 2. The positioning rod of the diagonal support body of the present invention is fully wrapped with double-sided sponge tape, and at the same time, the diagonal support blocks and the contact surfaces with the cushion layer are filled with double-sided sponge tape of specific thickness, which can effectively fill the gaps and prevent leakage during concrete pouring, thereby ensuring the quality of concrete pouring and structural integrity. In addition, through the disconnectable tension bolts and the waterproof tape sealing treatment at the contact points with the diagonal support blocks, effective support for the formwork is achieved, the stability and waterproofness of the connections of various components during the construction process are guaranteed, and the smooth progress of the caisson construction and the structural quality are ensured.

[0014] 3. The present invention pours concrete from low to high, in a symmetrical layered manner and by controlling the layer thickness, so that the concrete can rise evenly and be evenly stressed, thus avoiding deformation of the formwork due to uneven stress and ensuring the quality of the caisson structure. In addition, the displacement spacing of the inserted vibrator, the distance from the side formwork, the insertion depth of the lower layer and the duration of vibration can be used to fully vibrate the concrete, expel air and bubbles, make it dense and free of voids, and improve its strength and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of a caisson blade foot formwork reinforcement construction method of the present invention; Figure 2 A flow chart of the steel bar and template installation steps of a caisson blade foot template reinforcement construction method of the present invention; Figure 3 It is a schematic diagram of the installation of the diagonal bracing block of a caisson blade foot formwork reinforcement construction method of the present invention; Figure 4 A schematic diagram of template installation of a caisson blade foot template reinforcement construction method of the present invention; Figure 5 It is a schematic diagram of a caisson blade foot formwork reinforcement construction method after casting and forming according to the present invention; Figure 6It is a schematic diagram of the local structure of the diagonal bracing body of a caisson blade foot formwork reinforcement construction method of the present invention.

[0016] Among them, 1. diagonal support; 11. steel plate; 12. polystyrene filler; 13. positioning rod; 2. cushion layer; 3. formwork. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Please see attached Figure 1 - Attachment Figure 6 The embodiment of the present invention provides a method for reinforcing a caisson blade foot formwork, comprising the following steps: S1. Construction preparation: According to the caisson design drawing, deepen the diagonal brace 1 at the inner chamfer of the blade foot, make it in blocks and prepare conventional materials; S2, cushion layer 2 construction: first, locate the edge line of cushion layer 2 and the positioning holes of diagonal bracing body 1 at the construction site, and then proceed with cushion layer 2 construction after the bearing capacity and flatness meet the requirements; S3, installation of the diagonal brace body 1: locate the inner and outer edges of the caisson blade foot, and then install the diagonal brace blocks 1 one by one according to the positioning lines, and fill the contact surface between the diagonal brace blocks and the caisson cushion layer 2 with thick sponge double-sided tape; S4, installation of steel bars and formwork 3: Formwork 3 is made of multi-layer bamboo plywood, which is shaped according to the size and curvature of the inner and outer walls of the caisson, and the square caisson side wall formwork 3 is assembled according to the staggered joints of the upper and lower layers; S5, concrete pouring and curing: before pouring concrete, check the centerline position of the caisson and the reserved embedded position, check the reinforcement and joints of the template 3, remove debris, and then use the inserted vibrator to assist in concrete pouring, and perform curing after pouring; S6. Removal of formwork 3 and diagonal bracing blocks: Conduct a pressure test. When the concrete strength reaches 2.5 MPa, remove the side formwork that does not bear the weight of concrete. When the concrete reaches 75% of the design strength, remove formwork 3 and diagonal bracing blocks or pour the next section of concrete.

[0019] Specifically, through in-depth design in S1, the shape and size of the outer steel plate 11 of the diagonal support body 1 can be accurately designed according to the specific shape, size and force characteristics of the inner chamfer of the caisson blade foot, so that it fits perfectly with the chamfer, thereby achieving the best support effect, effectively preventing the blade foot template 3 from deforming during the concrete pouring process, and ensuring the structural accuracy of the caisson blade foot; The positioning edge line of the cushion layer 2 in S2 can determine the exact position of the caisson at the construction site, provide a benchmark for the subsequent construction of the caisson, ensure that the position of the caisson meets the design requirements, and avoid position deviations that affect the layout and use functions of the entire project. The accurate reservation of the positioning holes of the diagonal brace body 1 provides a guarantee for the accurate installation of the diagonal brace body 1, so that the diagonal brace body 1 can be installed according to the designed position, thereby effectively playing its supporting role on the blade foot template 3, ensuring the position accuracy of the blade foot template 3, and then ensuring that the shape and size of the blade foot of the caisson meet the design requirements; S3 accurately locates the inner and outer edge lines of the caisson blade foot, provides a precise reference for the installation of the diagonal brace block, ensures its accurate position in the caisson structure, and thus provides stable and reliable support for the entire blade foot formwork 3 reinforcement system. Installing the diagonal brace blocks one by one can more finely control the position and angle of each diagonal brace block, so that it can better adapt to the shape changes of the inner chamfer of the blade foot. Compared with the overall installation, it can effectively avoid the installation error caused by the larger overall size, further improve the support accuracy of the diagonal brace body 1 to the blade foot formwork 3, and ensure that the blade foot formwork 3 can be evenly and stably supported in all parts. At the same time, using sponge double-sided tape to fill the contact surface between them can effectively close these gaps, prevent the seepage of concrete slurry, ensure that the concrete can be evenly distributed in the formwork 3, ensure the quality of concrete pouring, and make the concrete structure of the caisson blade foot more compact and complete.

[0020] The template 3 in S4 is made of multi-layer bamboo plywood. Because of its flat and smooth surface, it can make the concrete surface smooth, reduce defects, and improve the appearance quality. At the same time, it is light in weight, easy to deform, and easy to carry and install, which can improve construction efficiency and reduce labor intensity. The inner and outer walls of the caisson usually have specific size and curvature requirements. By shaping the multi-layer bamboo plywood, it can be completely consistent with the actual shape of the caisson. In this way, when installing the template 3, it can be ensured that the template 3 is tightly fitted to the caisson structure without leaving any gaps, thereby effectively preventing concrete leakage during the pouring process, ensuring the quality of concrete pouring and the density of the caisson structure. At the same time, the staggered splicing method can make the upper and lower layers of the templates 3 bite each other to form an integral template 3 structure, and then in the subsequent concrete pouring process, the template 3 can better coordinate the force and jointly resist the lateral pressure generated by the concrete, enhance the overall stability of the template 3 system, and reduce the possibility of deformation of the template 3.

[0021] In S5, checking the centerline position of the caisson and the reserved embedded position can ensure the accuracy of the structural position and smooth subsequent connection. Checking the reinforcement and joints of formwork 3 and cleaning up debris can maintain the stability of formwork 3 and prevent leakage of slurry and mixing of debris. Using an inserted vibrator for pouring can make the concrete dense and uniform, and post-pouring maintenance can prevent cracking, improve strength and durability, thereby ensuring the pouring quality of caisson concrete, structural stability, and meeting design and use requirements from multiple aspects, thereby extending its service life.

[0022] The pressure test in S6 can detect whether the structural performance and stability of the caisson meet the standards. When the concrete strength reaches 2.5MPa, the non-weight-bearing side formwork is removed. This can not only ensure that the concrete has a certain self-stability at this time, but also facilitate subsequent construction operations and quality inspections. When the strength reaches 75%, formwork 3 and the diagonal brace blocks are removed or the second section of concrete is poured. This is because the concrete can withstand a greater load at this time. The removal operation will not affect the structural safety and can be flexibly arranged according to the progress of the project to ensure construction continuity and the overall structural quality of the caisson.

[0023] The diagonal brace body 1 in S1 includes an external steel plate 11, which is filled with a high-strength polystyrene filler 12 and a positioning rod 13. The positioning rod is used to position the plain round steel bars for welding under the diagonal brace body 1. The welding angle is consistent with the diagonal brace angle. A straight brace body is used at the groove of the caisson bottom plate, which includes an external bamboo plywood and is filled with a high-strength polystyrene filler 12. It is fixed to the inner formwork 3 with screws. Conventional materials include the formwork 3, three-section tension bolts, plain round steel bars and steel pipes, and auxiliary materials required for construction.

[0024] Specifically, the diagonal support body 1 cooperates with the straight support body and conventional materials. The external steel plate 11, the internal filling body and the positioning rod 13 of the diagonal support body 1 work together to accurately position and effectively support the blade foot template 3 to resist the pressure and deformation during concrete pouring. The bamboo plywood and the filling body of the straight support body are fixed to the inner template 3 by screws to stabilize the shape of the inner template 3. The template 3 made of conventional materials constructs the casting shape. The tension bolts, plain round steel bars and steel pipes reinforce the template 3 system. Auxiliary materials ensure the smooth progress of construction, and together provide stable and reliable structural support and construction conditions for the caisson construction, ensuring the structural accuracy and construction quality of the caisson.

[0025] Specifically, pre-buried PVC pipes are used to reserve positioning holes to provide accurate references for the precise installation of the diagonal brace 1, ensuring that its position and angle meet the design requirements and effectively play a supporting role. During the construction of the cushion layer 2, the width of both sides of the well wall is increased by 50 cm and the thickness reaches 25-30 cm. This can not only expand the bearing area and evenly distribute the caisson load to the foundation to prevent uneven settlement of the foundation, but also provide a flat, stable and sufficient operating space basic platform for the subsequent blade foot formwork 3 and related structure construction, thereby ensuring construction accuracy and structural stability.

[0026] When installing the positioning rod 13 in the diagonal brace body 1 in S3, a fully wrapped sponge double-sided tape is used, and the diagonal brace blocks 1 are filled with 1mm-2mm thick sponge double-sided tape. The thickness of the thick sponge double-sided tape between the diagonal brace block and the caisson cushion layer 2 is 2-3mm. Disconnectable tension bolts are used at the contact between the diagonal brace block and the tension bolts, and the contact points are sealed with waterproof tape.

[0027] Specifically, the positioning rod 13 of the diagonal brace body 1 is fully wrapped with sponge double-sided tape, and the diagonal brace blocks and the contact surfaces with the cushion layer 2 are respectively filled with sponge double-sided tape of specific thickness, which can effectively fill the gaps and prevent leakage during concrete pouring, which makes the subsequent diagonal brace blocks unable to be removed, thereby ensuring the quality of concrete pouring and structural integrity. The disconnectable tension bolts and the waterproof tape sealing treatment at the contact points with the diagonal brace blocks can not only achieve effective fastening and support of the formwork 3 by the tension bolts, but also facilitate the subsequent removal of the diagonal brace blocks, reduce damage to the structure and materials, and at the same time ensure the stability and waterproofness of the connections between the components during the construction process, thereby ensuring the smooth progress of the caisson construction and the structural quality.

[0028] The steps for installing the steel bars and formwork 3 in S4 include: S01, install the inner formwork 3 of the caisson and the straight support body at the groove of the bottom plate, and apply the release agent; S02, install the inclined iron at the bottom of the blade foot and the steel bar at the bottom of the blade foot; S03, the bottom inclined iron of the blade foot is welded and fixed to the bottom steel bar; S04. Continue to tie the upper reinforcement to the primary pouring height; S05. Install the outer formwork 3 and apply the release agent, install the tension screws and protective layer pads, and the spacing specifications of the tension screws, the spacing and specifications of the primary and secondary ribs shall be determined according to the design calculation; S06. Comprehensively check the installation quality and acceptance of template 3.

[0029] Specifically, the inner formwork 3 and the straight support body are installed first and the release agent is applied to facilitate the subsequent concrete demoulding and ensure the stability of the shape of the inner formwork 3. The inclined iron and the steel bar at the bottom of the blade foot are installed and welded to provide a solid foundation for the blade foot and enhance the integrity of the structure. Then, the upper steel bars are tied to the specified height to build the steel skeleton of the caisson to bear the load. Then, the outer formwork 3, tension screws and protective layer pads are installed to ensure that the position of the outer formwork 3 is accurate and stable, and the spacing and specifications of the formwork 3 are controlled to effectively resist the side pressure of the concrete, ensuring that the formwork 3 system is stable and reliable. Finally, a comprehensive inspection and acceptance can promptly discover and correct problems in the installation of the formwork 3, ensure that the installation of the caisson steel bars and formwork 3 meets the design requirements, lay a solid foundation for subsequent concrete pouring, and ensure the quality of the caisson structure and construction safety.

[0030] Concrete pouring in S5 is carried out according to the principle of "from low to high, symmetrical layering". The layer thickness is controlled at about 30cm. The displacement spacing of the inserted vibrator does not exceed 1.5 times the action radius of the vibrator. It maintains a distance of 5 to 10cm from the side formwork and is inserted into the lower layer of concrete at a depth of 5 to 10cm. The vibration duration of each vibration point is 20 to 30s. Concrete pouring is completed and cured in time. Moisture-retaining curing is used at 15-35℃ and heat-insulating curing is used at -5-15℃.

[0031] Specifically, pouring concrete according to the principle of "from low to high, symmetrical layering" and controlling the layer thickness to about 30cm can make the concrete rise evenly and the force be balanced, avoid deformation of the formwork 3 due to uneven force, ensure the quality of the caisson structure, and specify the displacement spacing of the inserted vibrator, the distance from the side form, the insertion depth of the lower layer and the vibration duration, which can fully vibrate the concrete, expel air and bubbles, make it dense and free of voids, and improve strength and durability. After that, timely maintenance is carried out after pouring. Moisturizing maintenance at 15-35℃ can prevent the surface moisture from evaporating too quickly and causing cracking. Thermal insulation maintenance at -5-15℃ can reduce temperature stress and prevent cracking, provide a suitable environment for concrete hardening, ensure its normal strength growth and structural stability, and meet the caisson design requirements and performance.

[0032] The concrete strength in S6 is determined by rebound test and test block strength test. The diagonal brace 1 is taken out by prying the bottom with a crowbar. The formwork 3 and the straight brace are not removed after being fixed. Cleaning and maintenance are carried out after the formwork 3, diagonal brace block and straight brace block are removed later.

[0033] Specifically, by jointly determining the concrete strength through rebound detection and test block strength test, the actual strength condition of the concrete can be accurately controlled, providing a scientific basis for the timing of removing the formwork 3 and the diagonal brace block, ensuring the safety of the removal operation without affecting the stability of the caisson structure, and the diagonal brace body 1 can be easily pried out from the bottom with a small crowbar after the concrete reaches the corresponding strength due to the specific design angle of the positioning rod 13, which not only reduces the difficulty of removal, but also minimizes the damage to the caisson structure and surrounding concrete to ensure the integrity of the structure. After that, the formwork 3 and the straight support body are fixed and not removed for the time being, which is beneficial to maintaining the integrity and stability of the caisson structure in subsequent construction; cleaning and maintenance are carried out after the final removal to remove debris, check the condition of components, extend the service life of the formwork 3, diagonal brace blocks and straight brace blocks, and provide reusable high-quality materials for subsequent similar projects, while ensuring that the entire caisson construction process is orderly and standardized, ensuring project quality and reducing costs.

[0034] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for reinforcing the caisson blade foot formwork, characterized in that: The following steps are involved: S1. Construction preparation: According to the caisson design drawings, deepen the diagonal brace at the inner chamfer of the blade foot, make it in blocks and prepare conventional materials; S2. Pad construction: First, locate the pad edge line and the positioning holes of the diagonal brace at the construction site. After the bearing capacity and flatness meet the requirements, proceed with pad construction; S3. Installation of diagonal brace: locate the inner and outer edges of the caisson blade foot, and then install the diagonal brace blocks one by one according to the positioning lines, and fill the contact surface between the diagonal brace blocks and the caisson cushion layer with thick sponge double-sided tape; S4. Installation of steel bars and formwork: The formwork is made of multi-layer bamboo plywood, which is shaped according to the size and curvature of the inner and outer walls of the caisson, and the square caisson side wall formwork is assembled with staggered joints of the upper and lower layers; S5. Concrete pouring and curing: Before pouring concrete, check the centerline position of the caisson and the reserved embedded position, check the template reinforcement and joints, remove debris, and then use an inserted vibrator to assist in concrete pouring, and perform curing after pouring; S6. Removal of formwork and diagonal bracing blocks: Conduct a pressure test. When the concrete strength reaches 2.5 MPa, remove the side formwork that does not bear the weight of concrete. When the concrete reaches 75% of the design strength, remove the formwork and diagonal bracing blocks or pour the next section of concrete.

2. A method for reinforcing the caisson blade foot formwork according to claim 1, characterized in that: The diagonal brace in S1 includes an external steel plate, which is filled with a high-strength polystyrene filler and a positioning rod. The positioning rod is used to position the plain round steel bars for welding under the diagonal brace. The welding angle is consistent with the diagonal brace angle. A straight brace is used at the groove of the caisson bottom plate, which includes an external bamboo plywood, which is filled with a high-strength polystyrene filler, and is fixed to the inner formwork with screws. The conventional materials include formwork, three-section tension bolts, plain round steel bars and steel pipes, and auxiliary materials required for construction.

3. A method for reinforcing the caisson blade foot formwork according to claim 1, characterized in that: The positioning holes in S2 are reserved holes for embedded PVC pipes, and the construction width of the cushion layer is 50 cm on both sides of the well wall, with a thickness of 25-30 cm.

4. A method for reinforcing the caisson blade foot formwork according to claim 1, characterized in that: When installing the positioning rod in the diagonal brace body in S3, a fully wrapped sponge double-sided tape is used. The diagonal brace blocks 1 are filled with 1mm-2mm thick sponge double-sided tape. The thickness of the thick sponge double-sided tape between the diagonal brace block and the contact surface of the caisson cushion is 2-3mm. Disconnectable tension bolts are used at the contact between the diagonal brace block and the tension bolts, and the contact points are sealed with waterproof tape.

5. A method for reinforcing the caisson blade foot formwork according to claim 1, characterized in that: The steps of installing the steel bars and the formwork in S4 include: S01. Install the formwork inside the caisson and the straight support body at the groove of the bottom plate, and apply the release agent; S02, install the inclined iron at the bottom of the blade foot and the steel bar at the bottom of the blade foot; S03, the bottom inclined iron of the blade foot is welded and fixed to the bottom steel bar; S04. Continue to tie the upper reinforcement to the primary pouring height; S05. Install the outer formwork and apply the release agent, install the tension screws and protective layer pads, and the spacing specifications of the tension screws, the spacing and specifications of the primary and secondary ribs must be determined according to the design calculation; S06. Comprehensively check the template installation quality and acceptance.

6. A method for reinforcing the caisson blade foot formwork according to claim 1, characterized in that: The concrete pouring in S5 is carried out according to the principle of "from low to high, symmetrical layering", and the layer thickness is controlled at about 30 cm. The displacement spacing of the inserted vibrator does not exceed 1.5 times the action radius of the vibrator, and it maintains a distance of 5 to 10 cm from the side form. The depth of insertion into the lower layer of concrete is 5 to 10 cm. The vibration duration of each vibration point is 20 to 30 seconds. After the concrete pouring is completed, it is promptly cured. The curing adopts moisturizing curing at 15-35°C and heat preservation curing at -5-15°C.

7. A method for reinforcing the caisson blade foot formwork according to claim 1, characterized in that: The concrete strength in S6 is determined by a rebound test and a test block strength test. The diagonal brace is taken out by prying the bottom surface with a crowbar. The formwork and the straight brace are not removed after being fixed. The formwork, diagonal brace block and straight brace block are subsequently removed for cleaning and maintenance.

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