阅读说明：本技术 钢板桩围堰支撑和防撞转换结构及施工方法 (Steel sheet pile cofferdam supporting and anti-collision conversion structure and construction method ) 是由 卫康 张东山 马宏宇 王家玉 郑春雨 于 2021-09-28 设计创作，主要内容包括：本发明公开了一种钢板桩围堰支撑和防撞转换结构及施工方法,通过在第一回填砂石层、第二回填砂石层的回填砂上浇筑第一砼圈梁、第二砼圈梁及第三砼圈梁,利用回填砂和第一至第三砼圈梁的自身的强度及混凝土的微膨胀性为钢板桩围堰提供充足的支撑力,保证钢板桩围堰根据浇筑钢板桩围堰内第一、二承台及桥墩的需要依次拆除第一内支撑结构、第二内支撑结构、第三内支撑结构后仍能确保钢板桩围堰安全可靠,同时为后续浇筑的承台、桥墩施工创造了干净、平整的作业平台。且能够在主桥完工通车或拆除钢板桩围堰后,使第一砼圈梁、第二砼圈梁、第三砼圈梁形成防撞转换圈梁且在防撞转换圈梁,可有效防止船只因操作失误或水中物撞击承台和桥墩,这种良好的防撞防御措施,即没有成本投入,但能取得良的附加效果。(The invention discloses a steel sheet pile cofferdam supporting and anti-collision conversion structure and a construction method, wherein a first concrete ring beam, a second concrete ring beam and a third concrete ring beam are poured on backfill sand of a first backfill sand stone layer and a second backfill sand stone layer, sufficient supporting force is provided for a steel sheet pile cofferdam by utilizing the self strength of the backfill sand and the first to third concrete ring beams and the micro expansibility of concrete, the steel sheet pile cofferdam can be ensured to be safe and reliable after a first inner supporting structure, a second inner supporting structure and a third inner supporting structure are sequentially dismantled according to the requirements of pouring a first bearing platform, a second bearing platform and a pier in the steel sheet pile cofferdam, and meanwhile, a clean and smooth operation platform is created for the subsequent pouring of the bearing platform and the pier. And after the main bridge is finished and the vehicle is started or the steel sheet pile cofferdam is removed, the first concrete ring beam, the second concrete ring beam and the third concrete ring beam form an anti-collision conversion ring beam and are arranged on the anti-collision conversion ring beam, so that ships can be effectively prevented from colliding a bearing platform and a pier due to misoperation or underwater objects, and the good anti-collision defense measure has no cost input but can obtain good additional effects.)

1. The utility model provides a steel sheet pile cofferdam supports and crashproof transform structure, comprises a plurality of pile foundations and the first cushion cap and the second cushion cap of pouring in proper order on a plurality of pile foundations, its characterized in that:

the first concrete ring beam is used for supporting the inner wall of the steel sheet pile cofferdam on the same plane after a poured first bearing platform is formed and before the first inner support structure is removed, the first concrete ring beam is positioned on the outer side of the upper part of the poured first bearing platform, the outer end face of the first concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the first concrete ring beam is connected to the side face of the first bearing platform which is correspondingly poured; or the outer end face of the first concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the first concrete ring beam is connected to the side face of the first bearing platform which is poured correspondingly through a plurality of supporting beams which are distributed at intervals;

the second concrete ring beam is used for supporting the inner wall of the steel sheet pile cofferdam on the same plane after a poured second bearing platform is formed and before a second inner support structure is removed, the second concrete ring beam is positioned on the outer side of the upper part of the poured second bearing platform, the outer end face of the second concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the second concrete ring beam is connected to the side face of the second bearing platform which is correspondingly poured; or the outer end face of the second concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the second concrete ring beam is connected to the side face of the second bearing platform which is poured correspondingly through a plurality of supporting beams which are distributed at intervals;

the third concrete ring beam is used for dismantling the inner wall of the steel sheet pile cofferdam supporting the same plane before the third inner support structure is removed when the pier in the cofferdam is poured at the upper end of the formed second bearing platform, the third concrete ring beam is positioned at the outer side of the pier in the same plane in the poured cofferdam, the outer end surface of the third concrete ring beam is propped against the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the third concrete ring beam is connected to the outer side surface of the corresponding pier pouring layer through a plurality of supporting beams distributed at intervals;

and the first concrete ring beam, the second concrete ring beam and the third concrete ring beam form the anti-collision conversion ring beam after the steel sheet pile cofferdam is removed.

2. The steel sheet pile cofferdam supporting and anti-collision conversion structure of claim 1, wherein: and a first sand-backfilling gravel layer is arranged in a space enclosed between the lower surface of the first concrete ring beam and the side surface of the first bearing platform as well as the inner wall of the steel sheet pile cofferdam at the corresponding position, and a first sand-backfilling gravel layer is arranged in a space enclosed between the lower surface of the second concrete ring beam and the inner wall of the steel sheet pile cofferdam at the corresponding position as well as the side surface of the second bearing platform.

3. The steel sheet pile cofferdam supporting and anti-collision conversion structure of claim 1, wherein: the height of the first concrete ring beam is 40-50 cm, the height of the second concrete ring beam is 40-50 cm, and the height of the third concrete ring beam is 40-50 cm.

4. The steel sheet pile cofferdam support system conversion structure of claim 1, wherein: the first concrete ring beam and the second concrete ring beam are poured by micro-expansion concrete.

5. The steel sheet pile cofferdam supporting and anti-collision conversion structure of claim 1, wherein: and the third concrete ring beam and the support beam are poured by reinforced micro-expansion concrete or reinforced concrete.

6. The steel sheet pile cofferdam supporting and anti-collision conversion structure of claim 1, wherein: and an anti-collision tire is arranged on the outer side of the anti-collision conversion ring beam.

7. A method of constructing a steel sheet pile cofferdam support and anti-collision conversion structure as claimed in claim 1, characterized in that: the method comprises the following steps:

(1) pouring a first bearing platform: according to the design, a pile foundation is arranged in a steel plate pile cofferdam, a bearing platform is arranged at the upper end of the pile foundation, the bearing platform is cast in two layers, the casting height of a first bearing platform is 2-2.8 m, the casting height of a second bearing platform is 2.5-3.5 m, the first bearing platform is cast at the upper end of the pile foundation, a concrete butt joint opening at the inner side of a first concrete ring beam is reserved on the outer side surface of the upper part of the cast first bearing platform according to the height of the first concrete ring beam or a concrete butt joint opening of each support beam is reserved according to the position of each support beam on the inner side surface of the first concrete ring beam, and a first bearing platform is formed;

(2) constructing a first backfill sand stone layer: constructing a first sand-backfilling gravel layer in a space defined by the outer side surface of the first bearing platform and the inner wall of the corresponding steel sheet pile cofferdam, compacting the first sand-backfilling gravel layer, pressing the lower end of the first sand-backfilling gravel layer on the ground in the corresponding steel sheet pile cofferdam, and setting the height of the upper end surface of the first sand-backfilling gravel layer from the upper end surface of the first bearing platform to be the height of a first concrete ring beam;

(3) pouring a first concrete ring beam:

(a) if the distance between the outer side surface of the first bearing platform and the inner wall of the corresponding steel sheet pile cofferdam is less than 1.2m, pouring a micro-expansion concrete layer in a space enclosed by the upper end surface of the backfill gravel layer, the outer side concrete butt joint port at the upper part of the poured first bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer, and forming a first concrete ring beam after the micro-expansion concrete layer reaches the design strength, wherein the outer end surface of the first concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the first concrete ring beam is connected in the concrete butt joint port at the side surface of the first bearing platform which is correspondingly poured;

(b) if the distance between the outer side surface of the first bearing platform and the inner wall of the corresponding steel sheet pile cofferdam is more than 1.2m, an inner end surface template of the first concrete ring beam and each supporting beam side template are arranged in a space defined by the upper end surface of the backfill gravel layer, the outer side of the upper part of the poured first bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer according to the designed inner end surface of the first concrete ring beam, each supporting beam and the corresponding reserved concrete butt joint position, and the distance between the inner end surface template of the first concrete ring beam and the corresponding inner wall of the steel sheet pile cofferdam is 70-100 cm; the distance between the two side templates corresponding to the same supporting beam is 1.2-1.5 m, the distance between two adjacent supporting beams is 3-4 m, a reinforcing steel bar framework is arranged in the supporting beam side template, one end of the reinforcing steel bar framework is butted with a reserved reinforcing steel bar of a reserved concrete butt joint port, the other end of the reinforcing steel bar framework extends into the inner end face template of the first concrete ring beam, pouring a micro-expansion concrete layer in a space enclosed by the upper end surface of the first backfill gravel layer, the templates on two sides of the same supporting beam and the outer side of the upper part of the poured first bearing platform, the template on the inner end surface and the inner wall of the steel sheet pile cofferdam on the same layer, after the micro-expansion concrete layer reaches the design strength, dismantling each template to form a first concrete ring beam, wherein the outer end face of the first concrete ring beam is supported against the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the first concrete ring beam is connected in the concrete butt joint port on the side face of the first bearing platform which is poured correspondingly through a plurality of supporting beams which are distributed at intervals; filling and compacting the first sand backfill layer until the first sand backfill layer is flush with the upper end surface of the first concrete ring beam;

(4) removing the first inner support structure;

(5) pouring a second bearing platform: according to the design, a second bearing platform is cast and constructed at the upper end of the first bearing platform, and concrete butt joints at the inner side of a second concrete ring beam are reserved on the outer side surface of the upper part of the cast second bearing platform according to the height of the second concrete ring beam or concrete butt joints of support beams are reserved according to the positions of the support beams on the inner side surface of the second concrete ring beam to form the second bearing platform;

(6) constructing a second backfill sand stone layer: constructing a second backfill gravel layer in a space defined between the outer side surface of the second bearing platform and the inner wall of the steel sheet pile cofferdam at the corresponding position, compacting the second backfill gravel layer, pressing the lower end of the second backfill gravel layer on the upper end surface of the first concrete ring beam or the first backfill gravel layer, and setting the height of the upper end surface of the second backfill gravel layer from the upper end surface of the second bearing platform as the height of the second concrete ring beam;

(7) pouring a second concrete ring beam:

(a) if the distance between the outer side surface of the second bearing platform and the inner wall of the corresponding steel sheet pile cofferdam is less than 1.2m, pouring a micro-expansion concrete layer in a space enclosed by the upper end surface of the backfill gravel layer, the outer side concrete butt joint at the upper part of the poured second bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer, and forming a second concrete ring beam after the micro-expansion concrete layer reaches the design strength, wherein the outer end surface of the second concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the second concrete ring beam is connected in the concrete butt joint at the side surface of the correspondingly poured second bearing platform;

(b) if the distance between the outer side surface of the second bearing platform and the inner wall of the corresponding steel sheet pile cofferdam is more than 1.2m, an inner end surface template of the second concrete ring beam and each supporting beam side template are arranged in a space defined by the upper end surface of the backfill gravel layer, the outer side of the upper part of the poured second bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer according to the designed inner end surface of the second concrete ring beam, each supporting beam and the corresponding reserved concrete butt joint position, and the distance between the inner end surface template of the second concrete ring beam and the corresponding inner wall of the steel sheet pile cofferdam is 70-100 cm; the distance between the two side templates corresponding to the same supporting beam is 1.2-1.5 m, the distance between two adjacent supporting beams is 3-4 m, a reinforcing steel bar framework is arranged in the supporting beam side template, one end of the reinforcing steel bar framework is butted with a reserved reinforcing steel bar of a reserved concrete butt joint port, the other end of the reinforcing steel bar framework extends into the inner end face template of the second concrete ring beam, pouring a micro-expansion concrete layer in the space enclosed by the upper end surface of the second backfill gravel layer, the templates on two sides of the same supporting beam and the outer side of the upper part of the poured second bearing platform, the template on the inner end surface and the inner wall of the steel sheet pile cofferdam on the same layer, after the micro-expansion concrete layer reaches the design strength, dismantling each template to form a second concrete ring beam, wherein the outer end face of the second concrete ring beam is supported against the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the second concrete ring beam is connected in a concrete butt joint port on the side face of a second bearing platform which is poured correspondingly through a plurality of support beams which are distributed at intervals; filling and compacting the second backfill sand stone layer to be flush with the upper end surface of the second concrete ring beam;

(8) removing the second inner support structure;

(9) pouring piers: building a pier pouring template and a support in the upper end of the second bearing platform and the steel sheet pile cofferdam, and pouring piers in the pier pouring template to the lower end of a third inner support structure supporting the same-layer steel sheet pile cofferdam;

(10) and (3) pouring a third concrete ring beam and a pier on the same layer: building a third concrete ring beam pouring template, a support and a plurality of supporting beam templates butted with the same-layer bridge piers, wherein the inner end face of the third concrete ring beam is the inner wall of the steel sheet pile cofferdam, reinforcing steel frameworks are arranged in the third concrete ring beam pouring template and the plurality of supporting beam templates, one end of each reinforcing steel framework in each supporting beam is butted with the corresponding side reinforcing steel framework in the poured bridge pier, and the other end of each reinforcing steel framework is butted with the corresponding side reinforcing steel framework in the first concrete ring beam; pouring concrete or micro-expansive concrete in the third concrete ring beam pouring template and the plurality of supporting beam templates, and pouring concrete in the pier templates at the same layer; after the micro-expansive concrete or the concrete reaches the designed strength, removing the templates to form a third concrete ring beam, wherein the outer end surface of the third concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the third concrete ring beam is connected with the side surface of the pier which is poured correspondingly through a plurality of supporting beams which are distributed at intervals;

(11) removing the third inner support structure, and continuing to finish the construction of pouring the pier;

(12) and removing the steel sheet pile cofferdam, forming an anti-collision conversion ring beam by the first concrete ring beam, the second concrete ring beam and the third concrete ring beam, and binding 1-2 layers of anti-collision tires outside the anti-collision conversion ring beam.

8. The method of claim 8, wherein: per cubic meter of micro-expansive concrete: 278Kg of cement, 54 Kg of fly ash, 792 Kg of mixed sand, 1094 Kg of pebbles, 157 Kg of water, 3.21 Kg of water reducing agent and 25 Kg of cement expanding agent;

the water reducing agent is a polycarboxylic acid water reducing agent, pebbles are of 5-31.5 mm synthetic grading, wherein pebbles of 5-15 mm account for 40%, pebbles of 16-20 mm account for 40%, and pebbles of 21-31.5 mm account for 20%.

9. The method of claim 8, wherein: and anti-sticking template oil is coated on the inner wall of the steel sheet pile cofferdam on the same layer as the first concrete ring beam, the second concrete ring beam and the third concrete ring beam during pouring.

Technical Field

The invention relates to the field of cofferdam support, in particular to a steel sheet pile cofferdam support and anti-collision conversion structure and a construction method.

Background

Constructing a pier or a main bridge bearing platform in a river by adopting steel sheet pile cofferdam construction, after the steel sheet pile cofferdam is formed, arranging a plurality of layers of inner supporting structures consisting of supporting columns and I-shaped steel in the steel sheet pile cofferdam from bottom to top for the water pressure outside the steel sheet pile cofferdam to be abutted against, wherein the I-shaped steel of the inner supporting structures is usually tightly attached to the inner wall of the steel sheet pile cofferdam at the corresponding position on the same layer, and then a plurality of supporting columns are used for supporting the inner end surfaces of the I-shaped steel positioned at the two side surfaces on the same layer of the inner wall of the steel sheet pile cofferdam to form each layer of inner supporting structures; such as: the main bridge of the river valley bridge is 420m long, the main bridge span is (110 +200+ 110) m, the main bridge bearing platform is located in the Hanjiang river, the main bridge bearing platform is 24m long, 19m wide and 5.5m high, the main bridge bearing platform is constructed by adopting a steel sheet pile cofferdam, the plane size of the cofferdam is 28.8m long and 22.8m wide, the depth of water outside the steel cofferdam is 5.9m when the water level is designed, the depth of soil penetration of the steel sheet pile outside the cofferdam after the foundation pit is excavated is 11.5m, and the depth of soil penetration of the steel sheet pile inside the cofferdam is 5.3 m. And then, arranging a pile foundation below the steel sheet pile cofferdam, arranging a bearing platform at the upper end of the pile foundation, and carrying out two-layer pouring construction on the bearing platform, wherein the pouring height of the first layer is 2.5m, the pouring height of the second layer is 3m, and the pier is positioned at the upper end of the bearing platform. The steel sheet pile cofferdam has three layers of inner supporting structures, the first layer of inner supporting structure is 50cm above the top surface of the first layer of bearing platform, the first layer of inner supporting structure can affect the construction of the second layer of bearing platform, therefore, before the second layer of bearing platform is constructed, the first layer of inner supporting structure on the bottom surface needs to be dismantled, meanwhile, the safety of the cofferdam structure needs to be ensured, and because a gap of about 2m exists between the bearing platform on the same layer and the cofferdam on the same layer, the gap needs to be backfilled after the construction of the first layer of bearing platform is completed. When the steel cofferdam structure is designed, a traditional sand backfilling mode is adopted, after sand is backfilled and after a first layer of inner supporting structure is removed, the deformation of the bottom of the steel sheet pile cofferdam is found to exceed a standard allowable value, the structure safety is seriously damaged, if a layer of inner supporting structure is required to be added on the first layer of inner supporting structure, the steel consumption is increased by about 57t if a single cofferdam is adopted for supporting, or the type of the steel sheet pile is increased (the steel consumption for a single cofferdam is increased by about 118.9 t), the steel consumption required to be increased in the traditional process is too large, the labor and the labor are wasted, the construction cost is increased, and the construction period is prolonged; and the arrangement of the support structures in each layer also influences the construction space of the bearing platform. Similarly, before the pier column or the tower column is constructed after the second-layer bearing platform is constructed, the supporting structure in the second layer needs to be removed, and the same problem still exists.

On the other hand, after the main bridge is finished or the vehicle is driven, the bearing platform and the bridge pier are often damaged due to misoperation of the ship or collision of objects in water, and no good defense measures are provided for the collision at present.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a steel sheet pile cofferdam supporting and anti-collision conversion structure and a construction method, which can ensure the structural safety of a steel cofferdam after supporting in a demolished part, save the consumption of steel, create a clean and smooth operation environment for the construction of a pouring layer, and have an anti-collision function after construction.

In order to solve the technical problems, the invention provides the following technical scheme: the utility model provides a steel sheet pile cofferdam supports and crashproof transform structure, comprises a plurality of pile foundations and first cushion cap and the second cushion cap of pouring in proper order on a plurality of pile foundations, wherein:

the first concrete ring beam is used for supporting the inner wall of the steel sheet pile cofferdam on the same plane after a poured first bearing platform is formed and before the first inner support structure is removed, the first concrete ring beam is positioned on the outer side of the upper part of the poured first bearing platform, the outer end face of the first concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the first concrete ring beam is connected to the side face of the first bearing platform which is correspondingly poured; or the outer end face of the first concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the first concrete ring beam is connected to the side face of the first bearing platform which is poured correspondingly through a plurality of supporting beams which are distributed at intervals;

the second concrete ring beam is used for supporting the inner wall of the steel sheet pile cofferdam on the same plane after a poured second bearing platform is formed and before a second inner support structure is removed, the second concrete ring beam is positioned on the outer side of the upper part of the poured second bearing platform, the outer end face of the second concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the second concrete ring beam is connected to the side face of the second bearing platform which is correspondingly poured; or the outer end face of the second concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the second concrete ring beam is connected to the side face of the second bearing platform which is poured correspondingly through a plurality of supporting beams which are distributed at intervals;

the third concrete ring beam is used for dismantling the inner wall of the steel sheet pile cofferdam supporting the same plane before the third inner support structure is removed when the pier in the cofferdam is poured at the upper end of the formed second bearing platform, the third concrete ring beam is positioned at the outer side of the pier in the same plane in the poured cofferdam, the outer end surface of the third concrete ring beam is propped against the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the third concrete ring beam is connected to the outer side surface of the corresponding pier pouring layer through a plurality of supporting beams distributed at intervals;

and the first concrete ring beam, the second concrete ring beam and the third concrete ring beam form the anti-collision conversion ring beam after the steel sheet pile cofferdam is removed.

As a preferable technical scheme of the invention, a first sand backfill layer is arranged in a space enclosed between the lower surface of the first concrete ring beam and the side surface of the first bearing platform as well as the inner wall of the steel sheet pile cofferdam at the corresponding position, and a first sand backfill layer is arranged in a space enclosed between the lower surface of the second concrete ring beam and the inner wall of the steel sheet pile cofferdam at the corresponding position as well as the side surface of the second bearing platform.

As a preferable technical scheme of the invention, the height of the first concrete ring beam is 40-50 cm, the height of the second concrete ring beam is 40-50 cm, and the height of the third concrete ring beam is 40-50 cm.

As a preferable technical scheme of the invention, the first concrete ring beam and the second concrete ring beam are cast by micro-expansion concrete.

As a preferable technical solution of the present invention, the third concrete ring beam and the support beam are poured with reinforced micro-expansive concrete or reinforced concrete.

As a preferable technical scheme of the invention, the outer side of the anti-collision conversion ring beam is provided with an anti-collision tire.

A construction method of a steel sheet pile cofferdam supporting and anti-collision conversion structure comprises the following steps:

(1) pouring a first bearing platform: according to the design, a pile foundation is arranged in a steel plate pile cofferdam, a bearing platform is arranged at the upper end of the pile foundation, the bearing platform is cast in two layers, the casting height of a first bearing platform is 2-2.8 m, the casting height of a second bearing platform is 2.5-3.5 m, the first bearing platform is cast at the upper end of the pile foundation, a concrete butt joint opening at the inner side of a first concrete ring beam is reserved on the outer side surface of the upper part of the cast first bearing platform according to the height of the first concrete ring beam or a concrete butt joint opening of each support beam is reserved according to the position of each support beam on the inner side surface of the first concrete ring beam, and a first bearing platform is formed;

(2) constructing a first backfill sand stone layer: constructing a first sand-backfilling gravel layer in a space defined by the outer side surface of the first bearing platform and the inner wall of the corresponding steel sheet pile cofferdam, compacting the first sand-backfilling gravel layer, pressing the lower end of the first sand-backfilling gravel layer on the ground in the corresponding steel sheet pile cofferdam, and setting the height of the upper end surface of the first sand-backfilling gravel layer from the upper end surface of the first bearing platform to be the height of a first concrete ring beam;

(3) pouring a first concrete ring beam:

(a) if the distance between the outer side surface of the first bearing platform and the inner wall of the corresponding steel sheet pile cofferdam is less than 1.2m, pouring a micro-expansion concrete layer in a space enclosed by the upper end surface of the backfill gravel layer, the outer side concrete butt joint port at the upper part of the poured first bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer, and forming a first concrete ring beam after the micro-expansion concrete layer reaches the design strength, wherein the outer end surface of the first concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the first concrete ring beam is connected in the concrete butt joint port at the side surface of the first bearing platform which is correspondingly poured;

(b) if the distance between the outer side surface of the first bearing platform and the inner wall of the corresponding steel sheet pile cofferdam is more than 1.2m, an inner end surface template of the first concrete ring beam and each supporting beam side template are arranged in a space defined by the upper end surface of the backfill gravel layer, the outer side of the upper part of the poured first bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer according to the designed inner end surface of the first concrete ring beam, each supporting beam and the corresponding reserved concrete butt joint position, and the distance between the inner end surface template of the first concrete ring beam and the corresponding inner wall of the steel sheet pile cofferdam is 70-100 cm; the distance between the two side templates corresponding to the same supporting beam is 1.2-1.5 m, the distance between two adjacent supporting beams is 3-4 m, a reinforcing steel bar framework is arranged in the supporting beam side template, one end of the reinforcing steel bar framework is butted with a reserved reinforcing steel bar of a reserved concrete butt joint port, the other end of the reinforcing steel bar framework extends into the inner end face template of the first concrete ring beam, pouring a micro-expansion concrete layer in a space enclosed by the upper end surface of the first backfill gravel layer, the templates on two sides of the same supporting beam and the outer side of the upper part of the poured first bearing platform, the template on the inner end surface and the inner wall of the steel sheet pile cofferdam on the same layer, after the micro-expansion concrete layer reaches the design strength, dismantling each template to form a first concrete ring beam, wherein the outer end face of the first concrete ring beam is supported against the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the first concrete ring beam is connected in the concrete butt joint port on the side face of the first bearing platform which is poured correspondingly through a plurality of supporting beams which are distributed at intervals; filling and compacting the first sand backfill layer until the first sand backfill layer is flush with the upper end surface of the first concrete ring beam;

(4) removing the first inner support structure;

(5) pouring a second bearing platform: according to the design, a second bearing platform is cast and constructed at the upper end of the first bearing platform, and concrete butt joints at the inner side of a second concrete ring beam are reserved on the outer side surface of the upper part of the cast second bearing platform according to the height of the second concrete ring beam or concrete butt joints of support beams are reserved according to the positions of the support beams on the inner side surface of the second concrete ring beam to form the second bearing platform;

(6) constructing a second backfill sand stone layer: constructing a second backfill gravel layer in a space defined between the outer side surface of the second bearing platform and the inner wall of the steel sheet pile cofferdam at the corresponding position, compacting the second backfill gravel layer, pressing the lower end of the second backfill gravel layer on the upper end surface of the first concrete ring beam or the first backfill gravel layer, and setting the height of the upper end surface of the second backfill gravel layer from the upper end surface of the second bearing platform as the height of the second concrete ring beam;

(7) pouring a second concrete ring beam:

(a) if the distance between the outer side surface of the second bearing platform and the inner wall of the corresponding steel sheet pile cofferdam is less than 1.2m, pouring a micro-expansion concrete layer in a space enclosed by the upper end surface of the backfill gravel layer, the outer side concrete butt joint at the upper part of the poured second bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer, and forming a second concrete ring beam after the micro-expansion concrete layer reaches the design strength, wherein the outer end surface of the second concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the second concrete ring beam is connected in the concrete butt joint at the side surface of the correspondingly poured second bearing platform;

(b) if the distance between the outer side surface of the second bearing platform and the inner wall of the corresponding steel sheet pile cofferdam is more than 1.2m, an inner end surface template of the second concrete ring beam and each supporting beam side template are arranged in a space defined by the upper end surface of the backfill gravel layer, the outer side of the upper part of the poured second bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer according to the designed inner end surface of the second concrete ring beam, each supporting beam and the corresponding reserved concrete butt joint position, and the distance between the inner end surface template of the second concrete ring beam and the corresponding inner wall of the steel sheet pile cofferdam is 70-100 cm; the distance between the two side templates corresponding to the same supporting beam is 1.2-1.5 m, the distance between two adjacent supporting beams is 3-4 m, a reinforcing steel bar framework is arranged in the supporting beam side template, one end of the reinforcing steel bar framework is butted with a reserved reinforcing steel bar of a reserved concrete butt joint port, the other end of the reinforcing steel bar framework extends into the inner end face template of the second concrete ring beam, pouring a micro-expansion concrete layer in the space enclosed by the upper end surface of the second backfill gravel layer, the templates on two sides of the same supporting beam and the outer side of the upper part of the poured second bearing platform, the template on the inner end surface and the inner wall of the steel sheet pile cofferdam on the same layer, after the micro-expansion concrete layer reaches the design strength, dismantling each template to form a second concrete ring beam, wherein the outer end face of the second concrete ring beam is supported against the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end face of the second concrete ring beam is connected in a concrete butt joint port on the side face of a second bearing platform which is poured correspondingly through a plurality of support beams which are distributed at intervals; filling and compacting the second backfill sand stone layer to be flush with the upper end surface of the second concrete ring beam;

(8) removing the second inner support structure;

(9) pouring piers: building a pier pouring template and a support in the upper end of the second bearing platform and the steel sheet pile cofferdam, and pouring piers in the pier pouring template to the lower end of a third inner support structure supporting the same-layer steel sheet pile cofferdam;

(10) and (3) pouring a third concrete ring beam and a pier on the same layer: building a third concrete ring beam pouring template, a support and a plurality of supporting beam templates butted with the same-layer bridge piers, wherein the inner end face of the third concrete ring beam is the inner wall of the steel sheet pile cofferdam, reinforcing steel frameworks are arranged in the third concrete ring beam pouring template and the plurality of supporting beam templates, one end of each reinforcing steel framework in each supporting beam is butted with the corresponding side reinforcing steel framework in the poured bridge pier, and the other end of each reinforcing steel framework is butted with the corresponding side reinforcing steel framework in the first concrete ring beam; pouring concrete or micro-expansive concrete in the third concrete ring beam pouring template and the plurality of supporting beam templates, and pouring concrete in the pier templates at the same layer; after the micro-expansive concrete or the concrete reaches the designed strength, removing the templates to form a third concrete ring beam, wherein the outer end surface of the third concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the third concrete ring beam is connected with the side surface of the pier which is poured correspondingly through a plurality of supporting beams which are distributed at intervals;

(11) removing the third inner support structure, and continuing to finish the construction of pouring the pier;

(12) and removing the steel sheet pile cofferdam, forming an anti-collision conversion ring beam by the first concrete ring beam, the second concrete ring beam and the third concrete ring beam, and binding 1-2 layers of anti-collision tires outside the anti-collision conversion ring beam.

As a preferred technical scheme of the invention, in per cubic meter of micro-expansive concrete: 278Kg of cement, 54 Kg of fly ash, 792 Kg of mixed sand, 1094 Kg of pebbles, 157 Kg of water, 3.21 Kg of water reducing agent and 25 Kg of cement expanding agent;

the water reducing agent is a polycarboxylic acid water reducing agent, pebbles are of 5-31.5 mm synthetic grading, wherein pebbles of 5-15 mm account for 40%, pebbles of 16-20 mm account for 40%, and pebbles of 21-31.5 mm account for 20%.

As a preferred technical scheme of the invention, the inner wall of the steel sheet pile cofferdam at the same layer as the first concrete ring beam, the second concrete ring beam and the third concrete ring beam is coated with anti-sticking template oil during pouring.

Compared with the prior art, the invention can achieve the following beneficial effects:

1. according to the invention, the first concrete ring beam, the second concrete ring beam and the third concrete ring beam are poured on the backfill sand of the first backfill sand stone layer and the second backfill sand stone layer, and the strength of the backfill sand and the strength of the first to third concrete ring beams and the micro expansibility of concrete are utilized to provide sufficient supporting force for the steel sheet pile cofferdam, so that the steel sheet pile cofferdam can be ensured to be safe and reliable after the first inner supporting structure, the second inner supporting structure and the third inner supporting structure are sequentially dismantled according to the requirements of pouring the first bearing platform, the second bearing platform and the bridge pier in the steel sheet pile cofferdam, and meanwhile, a clean and smooth operation platform is created for the subsequent construction of the bearing platform and the bridge pier.

2. The invention ensures that the poured bearing platform and the combination between the pier and the steel sheet pile are tighter, provides sufficient supporting force for the steel sheet pile, ensures that the steel sheet pile does not deform after the inner support of the demolished part of the steel sheet pile cofferdam is carried out, has safe and reliable structure and cofferdam back cover water-blocking effect, can effectively prevent the water seepage under the steel sheet pile cofferdam and outside the concrete ring beam from entering the cofferdam, and simultaneously creates a clean and flat operation platform for the subsequent construction in the steel sheet pile cofferdam.

3. According to the invention, after the main bridge is completely driven or the steel sheet pile cofferdam is removed, the first concrete ring beam, the second concrete ring beam and the third concrete ring beam form the anti-collision conversion ring beam, and 1-2 layers of anti-collision tires are tied outside the anti-collision conversion ring beam, so that the accident that a bearing platform and a pier are damaged due to misoperation of a ship or impact of objects in water on the bearing platform and the pier can be effectively prevented.

Drawings

FIG. 1 is a schematic diagram of a construction structure in a conventional steel sheet pile cofferdam;

FIG. 2 is a schematic view of a first concrete collar beam structure of the present invention;

FIG. 3 is a schematic view of the cross-sectional structure A-A of FIG. 2;

FIG. 4 is a schematic structural view of the present invention;

FIG. 5 is a schematic structural view of the present invention as an anti-collision transfer ring beam

Wherein: 1. a pile foundation; 2. a first bearing platform; 3. a steel sheet pile cofferdam; 4. a first backfill gravel layer; 5. a second platform; 6. the space in the steel sheet pile cofferdam; 7. a first inner support structure; 8. a second inner support structure; 9. a third inner support structure; 10. a bridge pier; 11. a first concrete ring beam; 12. a second concrete ring beam; 13. a support beam; 14. a second backfill gravel layer; 15. pouring a template for the third concrete ring beam; 16. a third concrete ring beam; 17. pouring a template for the pier; 18. a tire; 19. and (4) a bracket.

Detailed Description

The present invention will be further described with reference to specific embodiments for the purpose of facilitating an understanding of technical means, characteristics of creation, objectives and functions realized by the present invention, but the following embodiments are only preferred embodiments of the present invention, and are not intended to be exhaustive. Based on the embodiments in the implementation, other embodiments obtained by those skilled in the art without any creative efforts belong to the protection scope of the present invention. The experimental methods in the following examples are conventional methods unless otherwise specified, and materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Example 1 as shown in fig. 1 to 5, a valley bridge is a partial cable-stayed bridge with a main bridge length of 420m and a main bridge span of (110 +200+ 110) m, an X-th bearing platform of the main bridge is positioned in a hanjiang river and has a length of 24m, a width of 19m and a height of 5.5m, the X-th bearing platform is constructed by adopting a steel sheet pile cofferdam 3, and the plane dimension of the steel sheet pile cofferdam is 28.8m in length and 22.8m in width. Three layers of inner supporting structures which are a first inner supporting structure 7, a second inner supporting structure 8 and a third inner supporting structure 9 are arranged in the space 6 in the steel sheet pile cofferdam. The first inner supporting structure 7 is 50cm above the top surface of the first bearing platform 2, and the first inner supporting structure 7 can affect the construction of the second bearing platform 5, so that the first inner supporting structure 7 positioned at the bottom surface of the steel sheet pile cofferdam needs to be dismantled before the second bearing platform is constructed.

A construction method of a steel sheet pile cofferdam supporting and anti-collision conversion structure comprises the following steps:

(1) pouring a first bearing platform 2: according to the design, a pile foundation 1 is arranged below the steel sheet pile cofferdam 3, a bearing platform is arranged at the upper end of the pile foundation, the bearing platform is constructed in a two-layer pouring mode, the pouring height of the first bearing platform 2 is 2.8m, and the pouring height of the second bearing platform 5 is 3.5 m. Designing the height of the first concrete ring beam 11 to be 50cm and the width to be 90 cm; the height of the second concrete ring beam 12 is 50cm, and the width of the second concrete ring beam is 90 cm; the height of the third concrete ring beam 16 is 45cm, and the width is 100 cm; and each concrete ring beam is butted with the corresponding side surface of each bearing platform or pier through a plurality of supporting beams 13, the height of each supporting beam is 50cm, the width of each supporting beam is 1.3m, and the distance between two adjacent supporting beams on the same layer is 3.5 m.

A first bearing platform is firstly poured at the upper end of the pile foundation, and supporting beam concrete butt joints are reserved at the positions of supporting beams 13 on the inner side surface of a first concrete ring beam 11 on the outer side surface of the upper part of the poured first bearing platform according to the height 50cm and the width 90cm of the first concrete ring beam 11, so that a first bearing platform 2 is formed.

(2) Constructing a first backfill sand stone layer 4: and backfilling gravels in a space defined between the outer side surface of the first bearing platform and the inner wall of the steel sheet pile cofferdam at the corresponding position, and compacting the gravel-filled layer to form a first backfilled gravel layer 4. The lower end of the first sand-backfilled gravel layer is pressed on the ground in the corresponding steel plate pile cofferdam, and the height of the upper end face of the first sand-backfilled gravel layer from the upper end face of the first bearing platform is 50cm higher than that of the first concrete ring beam.

(3) Pouring the first concrete ring beam 11: because the distance between the outer side surface of the first bearing platform and the inner wall of the corresponding steel sheet pile cofferdam is more than 1.2m, an inner end surface template of the first concrete ring beam is arranged in a space enclosed by the upper end surface of the first backfill sand stone layer 4, the outer side of the upper part of the poured first bearing platform and the inner wall of the steel sheet pile cofferdam at the same layer, and the distance between the inner end surface template and the inner wall of the corresponding steel sheet pile cofferdam is 90 cm; two sides of the reserved butt joint of each supporting beam are provided with templates on two sides of the same supporting beam, the distance between the templates on two sides of the same supporting beam is 1.3m, and the distance between two adjacent supporting beams is 3.5 m. And a steel bar framework is respectively arranged in each supporting beam side template, one end of the steel bar framework is butted with the reserved steel bars of the reserved concrete butt joint port, and the other end of the steel bar framework extends into the inner end face template of the first concrete ring beam 11. Obviously, the upper end face of the corresponding first sand backfill layer is used as a bottom formwork for the first concrete ring beam 11 and each support beam. Pouring a micro-expansion concrete layer in a space enclosed by the templates on two sides of the same supporting beam and the outer side of the upper part of the poured first bearing platform and the templates on the inner end surface and the inner wall of the steel sheet pile cofferdam on the same layer, wherein the proportion of the micro-expansion concrete is shown in the following table 1:

TABLE 1

The water reducing agent is a polycarboxylic acid water reducing agent, the pebbles are of 5-31.5 mm synthetic grading, wherein the pebbles of 5-15 mm account for 40%, the pebbles of 16-20 mm account for 40%, and the pebbles of 21-31.5 mm account for 20%. The cement is 425 ordinary portland cement.

And after the micro-expansion concrete layer reaches the design strength, removing the templates to form a first concrete ring beam, wherein the outer end surface of the first concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the first concrete ring beam is connected in the concrete butt joint port on the side surface of the first bearing platform which is poured correspondingly through a plurality of supporting beams which are distributed at intervals.

(4) And filling and compacting the first sand backfilling sand layer to be flush with the upper end surface of the first concrete ring beam. The upper end surfaces of the first concrete ring beam and the support beams thereof and the upper end surface of the first bearing platform are on the same plane.

(5) The first inner support structure 7 is removed. At the moment, the first concrete ring beam 11 replaces the first inner support structure 7 to effectively support the inner wall of the steel sheet pile cofferdam on the same layer; and the space for pouring construction of the second bearing platform is purified.

(6) And (3) pouring a second bearing platform 5: according to the design, a second bearing platform 5 is cast and constructed at the upper end of the first bearing platform 2, and concrete butt joints of supporting beams are reserved on the outer side surface of the upper part of the cast second bearing platform according to the positions of the supporting beams 13 on the inner side surface of the second concrete ring beam 12 to form a second bearing platform;

(7) constructing a second backfill sand stone layer 14: constructing a second backfill gravel layer in a space defined between the outer side surface of the second bearing platform 5 and the inner wall of the steel sheet pile cofferdam 3 at the corresponding position, compacting the second backfill gravel layer, pressing the lower end of the second backfill gravel layer on the upper end surface of the first concrete ring beam or the first backfill gravel layer, and enabling the height of the upper end surface of the second backfill gravel layer from the upper end surface of the second bearing platform to be 50 cm;

(8) and (3) pouring a second concrete ring beam 12: because the distance between the outer side surface of the second bearing platform 5 and the inner wall of the corresponding steel sheet pile cofferdam is more than 1.2m, an inner end surface template and each supporting beam side template of the second concrete ring beam are arranged in a space defined by the upper end surface of the backfill gravel layer, the outer side of the upper part of the poured second bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer according to the designed inner end surface of the second concrete ring beam, each supporting beam and the corresponding reserved concrete butt joint position, the distance between the inner end surface template of the second concrete ring beam and the corresponding inner wall of the steel sheet pile cofferdam is 90cm, and the height of the poured second concrete ring beam is 50 cm; two sides of the reserved butt joint of each supporting beam are provided with templates on two sides of the same supporting beam, the distance between the templates on two sides of the same supporting beam is 1.3m, and the distance between two adjacent supporting beams is 3.5 m. And a steel bar framework is respectively arranged in each supporting beam side template, one end of the steel bar framework is butted with the reserved steel bars of the reserved concrete butt joint port, and the other end of the steel bar framework extends into the inner end face template of the second concrete ring beam 12. Obviously, the upper end surface of the corresponding second backfill gravel layer 14 is used as the bottom mold for the second concrete ring beam 12 and each support beam. And pouring a micro-expansion concrete layer in the space enclosed between the templates on two sides of the same supporting beam and the outer side of the upper part of the poured second bearing platform and between the template on the inner end surface and the inner wall of the steel sheet pile cofferdam on the same layer, wherein the proportion of the micro-expansion concrete is as shown in the table 1.

And after the micro-expansion concrete layer reaches the design strength, removing the templates to form a second concrete ring beam 12, wherein the outer end surface of the second concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the second concrete ring beam is connected in the concrete butt joint port on the side surface of the second bearing platform which is poured correspondingly through a plurality of supporting beams which are distributed at intervals.

(9) Filling and compacting the second backfill sand stone layer to be flush with the upper end surface of the second concrete ring beam; the upper end surfaces of the second concrete ring beam and the support beams thereof and the upper end surface of the second bearing platform are on the same plane.

(10) Removing the second inner support structure 8;

(11) pouring the bridge pier 10: and (3) building a pier pouring template 17 and a support 19 in the upper end of the second bearing platform 5 and the steel sheet pile cofferdam, and pouring piers in the pier pouring template to the lower end of a third inner support structure for supporting the same-layer steel sheet pile cofferdam.

(12) And (3) pouring a third concrete ring beam 16 and a pier on the same layer: and building a third concrete ring beam pouring template 15 (comprising two side templates and a bottom template), a support and a plurality of supporting beam templates (comprising two side templates and a bottom template) butted with the same-layer bridge piers. The inner end face of the third concrete ring beam is the inner wall of the steel sheet pile cofferdam, the length of the third concrete ring beam pouring template 15 from the corresponding inner wall of the steel sheet pile cofferdam is 100cm, and the casting height of the third concrete ring beam pouring template is 45 cm. Two sides of the reserved butt joint position of each supporting beam are provided with templates on two sides of the same supporting beam and a bottom template, the distance between the templates on two sides of the same supporting beam is 1.3m, and the distance between two adjacent supporting beams is 3.5 m. Reinforcing steel bar frameworks are arranged in the third concrete ring beam pouring template and the support beam templates, one end of each reinforcing steel bar framework in each support beam is in butt joint with the corresponding side reinforcing steel bar framework in the pouring bridge pier, and the other end of each reinforcing steel bar framework is in butt joint with the corresponding side reinforcing steel bar framework in the third concrete ring beam; pouring concrete or micro-expansive concrete in the third concrete ring beam pouring template and the plurality of supporting beam templates, and pouring concrete in the pier templates at the same layer; and after the micro-expansive concrete or the concrete reaches the designed strength, removing the templates to form a third concrete ring beam 16, wherein the outer end surface of the third concrete ring beam is supported on the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the third concrete ring beam is connected with the side surface of the pier which is poured correspondingly through a plurality of supporting beams which are distributed at intervals.

(13) And (5) removing the third inner support structure 9, and continuously completing the construction of pouring the pier.

(14) And (3) dismantling the steel sheet pile cofferdam: because the anti-sticking template oil is coated on the inner walls of the steel sheet pile cofferdams on the same layer before the first concrete ring beam, the second concrete ring beam and the third concrete ring beam are poured, the concrete ring beams cannot be damaged when the steel sheet pile cofferdams are dismantled. After the steel sheet pile cofferdam is removed, the first concrete ring beam 11, the second concrete ring beam 12 and the third concrete ring beam 16 form an anti-collision conversion ring beam, and 1-2 layers of anti-collision tires 18 are tied on the outer side of the anti-collision conversion ring beam. The anti-collision protective device can effectively prevent the ship from damaging the bearing platform and the bridge piers due to misoperation or impact of objects in water, and has good anti-collision protective measures, namely, no cost input but good additional effects.

Example 2 As shown in FIGS. 1 to 5, it was determined that the distance between the outer side surfaces of the first and second bearing platforms 2 and 5 and the inner wall of the corresponding steel sheet pile cofferdam was less than 1.2 m.

Then, the construction method of the steel sheet pile cofferdam supporting and anti-collision conversion structure comprises the following steps: according to the design, a pile foundation 1 is arranged below the steel sheet pile cofferdam 3, a bearing platform is arranged at the upper end of the pile foundation, the bearing platform is constructed in a two-layer pouring mode, the pouring height of the first bearing platform 2 is 2.5m, and the pouring height of the second bearing platform 5 is 3.2 m. The method comprises the steps of firstly pouring a first bearing platform 2 at the upper end of a pile foundation, and reserving a butt joint on the inner side surface of a first concrete ring beam 11 on the outer side surface of the upper part of the poured first bearing platform according to the height 50cm of the first concrete ring beam 11 to form the first bearing platform 2. And backfilling gravels in a space defined between the outer side surface of the first bearing platform and the inner wall of the steel sheet pile cofferdam at the corresponding position, and compacting the gravel-filled layer to form a first backfilled gravel layer 4. The lower end of the first sand-backfilled gravel layer is pressed on the ground in the corresponding steel plate pile cofferdam, and the height of the upper end face of the first sand-backfilled gravel layer from the upper end face of the first bearing platform is 50cm higher than that of the first concrete ring beam.

And pouring a first concrete ring beam 11, pouring a micro-expansion concrete layer in a space enclosed by the upper end surface of the backfill gravel layer, the outer side concrete butt joint port at the upper part of the poured first bearing platform and the inner wall of the steel sheet pile cofferdam on the same layer, and forming the first concrete ring beam after the micro-expansion concrete layer reaches the designed strength, wherein the outer end surface of the first concrete ring beam is propped against the inner wall of the steel sheet pile cofferdam on the same layer, and the inner end surface of the first concrete ring beam is connected in the concrete butt joint port at the side surface of the first bearing platform which is correspondingly poured. The upper end surface of the first concrete ring beam and the upper end surface of the first bearing platform are on the same plane.

The first inner support structure 7 is removed. At the moment, the first concrete ring beam 11 replaces the first inner support structure 7 to effectively support the inner wall of the steel sheet pile cofferdam on the same layer; and the space for pouring construction of the second bearing platform is purified.

And (3) pouring a second bearing platform 5: and (3) pouring a second bearing platform 5 at the upper end of the first bearing platform 2 according to the design, reserving concrete butt joints of the support beams on the outer side surface of the upper part of the poured second bearing platform according to the positions of the support beams 13 on the inner side surface of the second concrete ring beam 12, and forming the second bearing platform.

And constructing a second backfill gravel layer 14, constructing the second backfill gravel layer in a space enclosed between the outer side surface of the second bearing platform 5 and the inner wall of the steel sheet pile cofferdam 3 at the corresponding position, compacting the second backfill gravel layer, pressing the lower end of the second backfill gravel layer on the upper end surface of the first concrete ring beam, and enabling the height of the upper end surface of the second backfill gravel layer from the upper end surface of the second bearing platform to be 50cm higher than that of the second concrete ring beam.

And (3) pouring a second concrete ring beam 12: and pouring the second concrete ring beam according to the step of pouring the first concrete ring beam 11. The upper end surface of the second concrete ring beam and the upper end surface of the second bearing platform are on the same plane.

The second internal support structure 8 is removed. The method comprises the following steps: the construction steps of pouring the pier 10, pouring the third concrete ring beam 16 and piers on the same layer, removing the third inner support structure 9, continuing to complete the construction of pouring the pier, removing the steel sheet pile cofferdam and the like are the same as those in the embodiment 1, so the description is omitted.

After the steel sheet pile cofferdam is removed, the first concrete ring beam 11, the second concrete ring beam 12 and the third concrete ring beam 16 form an anti-collision conversion ring beam, and 1-2 layers of anti-collision tires 18 are tied on the outer side of the anti-collision conversion ring beam. The anti-collision protective device can effectively prevent the ship from damaging the bearing platform and the bridge piers due to misoperation or impact of objects in water, and has good anti-collision protective measures, namely, no cost input but good additional effects.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and the preferred embodiments of the present invention are described in the above embodiments and the description, and are not intended to limit the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.